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		<title>网络中心性</title>
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		<updated>2020-12-10T07:32:16Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* 网络流特征Characterization by network flows */&lt;/p&gt;
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&lt;div&gt;此词条暂由水流心不竞初译，未经审校，带来阅读不便，请见谅。&lt;br /&gt;
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{{for|the statistical concept|Central tendency}}&lt;br /&gt;
{{Network Science}}&lt;br /&gt;
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In [[graph theory]] and [[network theory|network analysis]], indicators of '''centrality''' identify the most important [[vertex (graph theory)|vertices]] within a graph. Applications include identifying the most influential person(s) in a [[social network]], key infrastructure nodes in the [[Internet]] or [[urban network]]s, and [[super-spreader]]s of disease. Centrality concepts were first developed in [[social network analysis]], and many of the terms used to measure centrality reflect their [[sociology|sociological]] origin.&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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In graph theory and network analysis, indicators of centrality identify the most important vertices within a graph. Applications include identifying the most influential person(s) in a social network, key infrastructure nodes in the Internet or urban networks, and super-spreaders of disease. Centrality concepts were first developed in , and many of the terms used to measure centrality reflect their sociological origin.&lt;br /&gt;
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They should not be confused with [[node influence metric]]s, which seek to quantify the influence of every node in the network.&lt;br /&gt;
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They should not be confused with node influence metrics, which seek to quantify the influence of every node in the network.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;图论 graph theory &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络分析 network analysis &amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性 centrality &amp;lt;/font&amp;gt;'''指标用于识别图中最重要的顶点。其应用包括在社会网络中识别出最有影响力的个人，在因特网或城市网络中识别出最为关键的基础设施节点，以及识别疾病的超级传播者。中心性的概念最初由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;社会网络分析 social network analysis&amp;lt;/font&amp;gt;'''所发展，因此许多用于衡量中心性的术语都反映出了它们的社会学出身。&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;中心性不应与节点影响度相混淆，后者意在量化网络中每个节点的影响。&lt;br /&gt;
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==中心性指数的定义与特性Definition and characterization of centrality indices==&lt;br /&gt;
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Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性指数 centrality indices&amp;lt;/font&amp;gt;'''旨在探寻如何描绘重要节点这一问题。这一问题的答案通常实值函数的形式给出，可根据函数值将图中各节点进行排序，进而确定最为重要的节点。&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
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The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
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“重要性”的含义十分广泛，因此导致了许多不同的中心性定义方式，我们可以将各种不同的定义方式划分为如下两类。&lt;br /&gt;
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&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important.&amp;lt;ref name=Borgatti2005/&amp;gt; &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt; Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important. &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&lt;br /&gt;
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“重要性”可以被设想为与网络中的某种流动或传输有关。&amp;lt;ref name=Borgatti2005/&amp;gt; “重要性”也可以被设想为与网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;内聚力 cohesiveness&amp;lt;/font&amp;gt;'''有关。这允许我们根据内聚力的不同测量方式对中心性予以分类。&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;这些方法将中心性划分于完全不同的类别中，也就是在一种类别中的中心性往往无法适用于其他类别。&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one ([[Centrality#Degree centrality|degree centrality]]) to infinite walks ([[Centrality#Eigenvector centrality|eigenvalue centrality]]).&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=&amp;quot;Benzi2013&amp;quot;&amp;gt;{{cite journal | last1=Benzi | first1=Michele | last2=Klymko| first2=Christine | year=2013 |title= A matrix analysis of different centrality measures |arxiv=1312.6722 | doi=10.1137/130950550 | volume=36 | issue=2 | journal=SIAM Journal on Matrix Analysis and Applications | pages=686–706}}&amp;lt;/ref&amp;gt; The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one (degree centrality) to infinite walks (eigenvalue centrality). The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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当根据内聚力方法对中心性进行分类时，很明显大多数中心性都将被划分于同一类别。起始于给定顶点的步数总和仅取决于步数的定义以及计数方式。这种分类方式的不足表现为它仅能较弱的描绘中心性特征，即按照一步步度（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;度中心性 degree centrality&amp;lt;/font&amp;gt;'''）到无穷步步长（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 eigenvalue centrality&amp;lt;/font&amp;gt;'''）的方式将中心性置于一种光谱状的分类中。&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=&amp;quot;Benzi2013&amp;quot;&amp;gt;{{cite journal | last1=Benzi | first1=Michele | last2=Klymko| first2=Christine | year=2013 |title= A matrix analysis of different centrality measures |arxiv=1312.6722 | doi=10.1137/130950550 | volume=36 | issue=2 | journal=SIAM Journal on Matrix Analysis and Applications | pages=686–706}}&amp;lt;/ref&amp;gt; 对于采用类似方式定义的各种中心性的观察也表明了这些指数之间的高阶相关性。&lt;br /&gt;
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===网络流特征Characterization by network flows===&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at once.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at oe.&lt;br /&gt;
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一个网络可以被看成是对某种物体流动的路径描述。使基于流的类型和由中心性编码的路径类型（同时）得到表征。一个流可以基于传输，每个不可分割的项目从一个节点到另一个节点，就像一个包裹从配送站送到客户的房子。第二种情况是串行复制，在这种情况下，一个项从源节点被复制到达目标节点。例如通过流言传播信息，以私有方式传播信息，并在流程结束时通知源节点和目标节点。最后一种情况是并行复制，即同时将项目复制到多个链接，就像无线电广播一次性向多个听众提供相同的信息。&lt;br /&gt;
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Likewise, the type of path can be constrained to [[Distance (graph theory)|geodesics]] (shortest paths), [[Glossary of graph theory terms#path|paths]]  (no vertex is visited more than once), [[Glossary of graph theory terms#trail|trails]] (vertices can be visited multiple times, no edge is traversed more than once), or [[Glossary of graph theory terms#walk|walks]] (vertices and edges can be visited/traversed multiple times).&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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Likewise, the type of path can be constrained to geodesics (shortest paths), paths  (no vertex is visited more than once), trails (vertices can be visited multiple times, no edge is traversed more than once), or walks (vertices and edges can be visited/traversed multiple times).&lt;br /&gt;
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同样，路径类型可以被限定为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Distance &amp;lt;/font&amp;gt;'''(最短路径)、路径(对顶点的访问不超过一次)、小径(可以访问多次顶点，没有边被访问超过一次)或者步子(可以访问/遍历多次顶点和边)。&lt;br /&gt;
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===行走结构特征Characterization by walk structure===&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either ''radial'' or ''medial.'' Radial centralities count walks which start/end from the given vertex. The [[Centrality#Degree centrality|degree]] and [[Centrality#Eigenvector centrality|eigenvalue]] centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's [[Centrality#Betweenness centrality|betweenness]] centrality, the number of shortest paths which pass through the given vertex.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either radial or medial. Radial centralities count walks which start/end from the given vertex. The degree and eigenvalue centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's betweenness centrality, the number of shortest paths which pass through the given vertex.&lt;br /&gt;
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可以从中心性的构造方式推导出另一种分类方法。这又分成了两个类。中心点可以是放射状的，也可以是内侧的。从给定顶点开始/结束的径向中心点数。度和特征值中心是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 径向中心Radial centralities&amp;lt;/font&amp;gt;'''的例子，计算长度为一或无穷大的行走的个数。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中间中心性Medial centralities&amp;lt;/font&amp;gt;'''计算通过给定顶点的步数。典型的例子是 弗里曼的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality,&amp;lt;/font&amp;gt;'''，即穿过给定顶点的最短路径的数量。&lt;br /&gt;
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Likewise, the counting can capture either the ''volume'' or the ''length'' of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's [[Centrality#Closeness centrality|closeness]] centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example.&amp;lt;ref name=Borgatti2006/&amp;gt; Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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Likewise, the counting can capture either the volume or the length of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's closeness centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example. Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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同样地，计数可以抓住行走的体积或长度。体积是给定类型的行走的总数。上一段的三个例子就属于这一类。长度则给出从给定顶点到图中其余顶点的距离。弗里曼 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，即从一个给定顶点到所有其他顶点的测地距离，是最著名的例子。请注意，这种分类独立于步行计数的类型(即：步行，小道，路径，测地线)。&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&lt;br /&gt;
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博尔加蒂和埃弗雷特提出，这种类型学为如何最好地比较中心性度量提出了建议。在这个22分类中，放在同一盒子中的中心点足够相似，可以做出合理的选择; 人们可以合理地比较哪个对于给定的应用更好。然而，不同盒子中的度量方法是截然不同的。只有在预先确定哪个类别更适用的情况下，对相对适应性的评估才会发生，这使得比较变得毫无意义。&lt;br /&gt;
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===光谱上存在的径向体积中心Radial-volume centralities exist on a spectrum===&lt;br /&gt;
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The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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步行结构的特征表明，几乎所有广泛使用的中心性都是径向体积的衡量。这得出结论顶点的中心性是与之相关联的顶点中心性的函数。中心性根据如何定义关联而不同。&lt;br /&gt;
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Bonacich showed that if association is defined in terms of [[Glossary of graph theory terms#walk|walks]], then a family of centralities can be defined based on the length of walk considered.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;/&amp;gt; [[Centrality#Degree centrality|Degree centrality]] counts walks of length one, while [[Centrality#Eigenvector centrality|eigenvalue centrality]] counts walks of length infinity. Alternative definitions of association are also reasonable. [[Alpha centrality]] allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich showed that if association is defined in terms of walks, then a family of centralities can be defined based on the length of walk considered. Degree centrality counts walks of length one, while eigenvalue centrality counts walks of length infinity. Alternative definitions of association are also reasonable. Alpha centrality allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich 指出，如果联想是根据行走来定义的，那么可以根据考虑的行走长度来定义一个中心性家族。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''计算长度为1的行走，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征值中心性Eigenvalue centrality  &amp;lt;/font&amp;gt;'''计算长度为无穷大的行走。关联的其他定义也是合理的。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 阿尔法中心性Alpha centrality&amp;lt;/font&amp;gt;'''允许顶点有一个外部影响源。埃斯特拉达的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图中心性Subgraph centrality &amp;lt;/font&amp;gt;'''提出只计算封闭路径(三角形、正方形等)。).&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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这些测量方法的核心是这种现象：图中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵&amp;lt;/font&amp;gt;'''的幂给出了由该幂给出的散步长度的数目。同样，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 矩阵指数Matrix exponential&amp;lt;/font&amp;gt;'''也与给定长度的行走次数密切相关。邻接矩阵的初始转换允许对步行计数的类型进行不同的定义。无论采用哪种方法，顶点的中心性都可以表示为无穷和&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum _ { k = 0} ^ infty a _ { r } ^ { k } beta ^ k &amp;lt;/math &amp;gt; &lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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矩阵能量或者&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum { k = 0} ^ infty frac {(a _ r beta) ^ k }{ k！{/math &amp;gt; &lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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对于矩阵指数函数，其中&lt;br /&gt;
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* &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; is walk length,&lt;br /&gt;
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* &amp;lt;math&amp;gt;A_R&amp;lt;/math&amp;gt; is the transformed adjacency matrix, and&lt;br /&gt;
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* &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; is a discount parameter which ensures convergence of the sum.&lt;br /&gt;
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K为步长，A_R是邻接矩阵的转秩，贝达是保证收敛的折扣参数。&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. [[Alpha centrality]] replaces the adjacency matrix with its [[resolvent formalism|resolvent]]. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to [[Centrality#Degree centrality|degree centrality]]. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to [[Centrality#Eigenvector centrality|eigenvalue centrality]].&amp;lt;ref name=Benzi2013/&amp;gt;&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. Alpha centrality replaces the adjacency matrix with its resolvent. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to degree centrality. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to eigenvalue centrality.&lt;br /&gt;
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博纳奇的一系列措施并没有改变邻接矩阵。阿尔法集中性用它的解决方案替代了邻接矩阵。子图集中性用它的踪迹取代了邻接矩阵。一个令人吃惊的结论是，不管邻接矩阵最初的转变是什么，所有这些方法都有共同的限制行为。随着贝塔系数趋近于零，指数收敛到度中心性。随着贝塔系数接近其最大值，指数收敛到特征值的中心性。&lt;br /&gt;
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===博弈论中心性Game-theoretic centrality===&lt;br /&gt;
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The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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上述大多数标准措施的共同特点是，它们通过只关注一个节点本身所扮演的角色来评估确定节点的重要性。然而, 在许多应用中，这种方法是不充分的，因为可能会发生协同作用&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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如果将节点的功能分组考虑。&lt;br /&gt;
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[[File:Game-theoretic centrality.png|Example of game-theoretic centrality]]&lt;br /&gt;
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Example of game-theoretic centrality&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''的例子&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in &amp;lt;ref&amp;gt;Michalak, Aadithya, Szczepański, Ravindran, &amp;amp; Jennings {{ArXiv|1402.0567}}&amp;lt;/ref&amp;gt; uses the [[Shapley value]]. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in  uses the Shapley value. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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例如，考虑阻止流行病的问题。看看上面的网络图像，我们应该给哪些节点接种疫苗？基于前面描述的措施，我们希望识别在疾病传播中最重要的节点。仅仅基于中心的方法，即关注节点的个别特性，可能不是一个好主意。红色方块中的节点，单独不能阻止疾病的传播，但把它们作为一个群体来考虑，我们清楚地看到，如果疾病在节点 &amp;lt; math &amp;gt; v _ 1 &amp;lt;/math &amp;gt; 、 &amp;lt; math &amp;gt; v _ 4 &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; v _ 5 &amp;lt;/math &amp;gt; 中开始，它们就能阻止疾病的传播。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''试图利用博弈论中的工具来研究所描述的问题和机会。本文提出的方法使用了 Shapley 值。由于 Shapley 值计算的时间复杂性，这一领域的大部分工作都集中在实现新的算法和方法，这些算法和方法依赖于网络的特殊拓扑结构或问题的特殊性质。这种方法可以将时间复杂度从指数级降低到多项式级。&lt;br /&gt;
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Similarly, the solution concept [[authority distribution]] (&amp;lt;ref&amp;gt;{{cite journal |last=Hu |first=Xingwei |first2=Lloyd |last2=Shapley |title=On Authority Distributions in Organizations |journal=Games and Economic Behavior |volume=45 |pages=132–170 |year=2003 | doi = 10.1016/s0899-8256(03)00130-1 }}&amp;lt;/ref&amp;gt;) applies the [[Shapley-Shubik power index]], rather than the [[Shapley value]], to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020)&amp;lt;ref&amp;gt;{{cite journal|last=Hu|first=Xingwei|year=2020|volume=7|title=Sorting big data by revealed preference with application to college ranking |journal=Journal of Big Data|doi=10.1186/s40537-020-00300-1|doi-access=free}}&amp;lt;/ref&amp;gt;, such as ranking U.S. colleges.&lt;br /&gt;
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Similarly, the solution concept authority distribution () applies the Shapley-Shubik power index, rather than the Shapley value, to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020), such as ranking U.S. colleges.&lt;br /&gt;
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同样，'''&amp;lt;font color=&amp;quot;#CD32CD&amp;quot;&amp;gt; 加权分布概念的解()The solution concept authority distribution () &amp;lt;/font&amp;gt;'''采用 Shapley-Shubik 幂指数，而不是 Shapley 值来衡量双方之间的直接影响。这种分布确实是一种产生'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征向量中心性Engenvector centrality&amp;lt;/font&amp;gt;'''的类型。它用于对 Hu (2020)中的大数据对象进行排序，比如美国大学排名。&lt;br /&gt;
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== 重要限制Important limitations ==&lt;br /&gt;
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Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the [[Krackhardt kite graph]], for which three different notions of centrality give three different choices of the most central vertex.&amp;lt;ref&amp;gt;{{cite journal|title=Assessing the Political Landscape: Structure, Cognition, and Power in Organizations|first=David|last=Krackhardt|authorlink=David Krackhardt|journal=Administrative Science Quarterly|volume=35|issue=2|date=June 1990|pages=342–369|doi=10.2307/2393394|jstor=2393394}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the Krackhardt kite graph, for which three different notions of centrality give three different choices of the most central vertex.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中心性Centrality&amp;lt;/font&amp;gt;'''指标有两个重要的局限性，一个显而易见，另一个则不易察觉。显而易见的局限性是，对于一个应用最优的中心性对于另一个应用常常是次优的。事实上，如果不是这样，我们就不需要这么多不同的中心性。克拉克哈特风筝图为这一现象提供了一个例证，对于这个图，三个不同的中心性概念给出了三个最中心顶点的不同选择。&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices.&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=Borgatti2005/&amp;gt; This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  [[node influence metric]]s to address this problem.&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices. This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  node influence metrics to address this problem.&lt;br /&gt;
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更不易察觉的限制是通常会错误地认为顶点中心性表示顶点的相对重要性。中心性指数被明确地设计来产生一个指出最重要顶点的排名。在刚才提到的限制下，他们做得很好。它们通常不用来测量节点的影响力。最近，网络物理学家开始开发'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;节点影响度量Node influence metrics &amp;lt;/font&amp;gt;'''来解决这个问题。&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying [[Centrality#Freeman centralization|Freeman centralization]] to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt; This approach, however, is seldom seen in practice.{{citation needed|reason=I've come across quite some theoretical studies that indicate otherwise. My suggestion is to remove this sentence, if reasonable citation is not provided.|date=September 2015}}&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying Freeman centralization to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores. This approach, however, is seldom seen in practice.&lt;br /&gt;
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错误有两方面。首先，一个排名只根据顶点的重要性排序，它并不对节点重要性的不同水平进行量化区分。这可以通过将 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;'''应用到中心性度量来缓解，这种度量可以根据节点的不同中心性得分来判断节点的重要性。此外， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;''使人们能够通过比较几个网络的最高中心性得分来比较它们。然而，这种方法在实践中很少见到。&lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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其次，用以(正确地)识别给定网络/应用中最重要顶点的特征并不一定可推广到其余顶点。&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot; /&amp;gt;&amp;lt;ref name=&amp;quot;daSilva2012&amp;quot;&amp;gt;{{cite journal | last1=da Silva|first1=Renato |last2=Viana|first2=Matheus|last3=da F. Costa |first3=Luciano| title=Predicting epidemic outbreak from individual features of the spreaders| journal=J. Stat. Mech.: Theory Exp. | year=2012|volume=2012|pages=P07005|number=7 | doi=10.1088/1742-5468/2012/07/p07005|arxiv=1202.0024|bibcode=2012JSMTE..07..005A}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Bauer2012&amp;quot;&amp;gt;{{cite journal | last1=Bauer|first1=Frank | last2=Lizier|first2=Joseph|title=Identifying influential spreaders and efficiently estimating infection numbers in epidemic models: A walk counting approach| journal=Europhys Lett | year=2012| volume=99| pages=68007|number=6 | doi=10.1209/0295-5075/99/68007|arxiv=1203.0502|bibcode=2012EL.....9968007B}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Sikic2013&amp;quot;&amp;gt;{{ cite journal| last1= Sikic| first1=Mile|last2=Lancic|first2=Alen|last3=Antulov-Fantulin|first3=Nino|last4=Stefanic|first4=Hrvoje| title = Epidemic centrality -- is there an underestimated epidemic impact of network peripheral nodes? |journal = The European Physical Journal B |volume=86 |number=10 |pages=1–13 |year=2013 | doi=10.1140/epjb/e2013-31025-5|arxiv=1110.2558 | bibcode=2013EPJB...86..440S}}&amp;lt;/ref&amp;gt; This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&amp;lt;ref name=&amp;quot;Ghoshal2011&amp;quot;&amp;gt;{{cite journal | last1=Ghoshal | first1= G. | last2= Barabsi |first2= A L | title = Ranking stability and super-stable nodes in complex networks. | journal = Nat Commun | volume =2 | page = 394| year= 2011 | doi=10.1038/ncomms1396 | pmid= 21772265 | bibcode=2011NatCo...2..394G | doi-access= free }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless. This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&lt;br /&gt;
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对于大多数其他网络节点，排名可能是没有意义的。这就解释了为什么，例如，只有谷歌图片搜索的前几个结果以合理的顺序出现。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页排名Pagerank&amp;lt;/font&amp;gt;'''是一个非常不稳定的度量，显示了在跳转参数小的调整之后频繁的秩逆转。&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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虽然中心性指数未能推广到网络的其他部分，乍看起来似乎是违反直觉的，但它直接遵循上述定义。&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot;&amp;gt;{{cite journal |last1= Lawyer |first1= Glenn |year= 2015 |title= Understanding the spreading power of all nodes in a network: a continuous-time perspective |journal=Sci Rep |volume=5|pages=8665|doi=10.1038/srep08665 |pmid=25727453 |pmc=4345333|arxiv=1405.6707|bibcode=2015NatSR...5E8665L}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&lt;br /&gt;
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复杂网络具有异构的拓扑结构。由于最佳度量取决于最重要顶点的网络结构，对于这些顶点最优的度量对于网络的其余部分是次优的。&lt;br /&gt;
&lt;br /&gt;
==Degree centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Degree (graph theory)}} &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:6 centrality measures.png|thumb|right|300px|Examples of A) [[Betweenness centrality]], B) [[Closeness centrality]], C) [[Eigenvector centrality]], D) [[Degree centrality]], E) [[Centrality#Harmonic centrality|Harmonic centrality]] and F) [[Katz centrality]] of the same graph.]]&lt;br /&gt;
&lt;br /&gt;
Examples of A) [[Betweenness centrality, B) Closeness centrality, C) Eigenvector centrality, D) Degree centrality, E) Harmonic centrality and F) Katz centrality of the same graph.]]&lt;br /&gt;
&lt;br /&gt;
实例 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; a)[中介中心性A) [[Betweenness centrality,b)紧密中心性，B) Closeness centrality, c)特征向量中心性，C) Eigenvector centrality, d)度中心性，D) Degree centrality, e)调和中心性，E) Harmonic centrality andf) 卡兹Katz 中心性]F) Katz centrality .]]&amp;lt;/font&amp;gt;'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Historically first and conceptually simplest is '''degree centrality''', which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely [[indegree]] and [[outdegree]]. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
&lt;br /&gt;
Historically first and conceptually simplest is degree centrality, which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely indegree and outdegree. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
&lt;br /&gt;
历史上最简单的概念是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''，它定义为一个节点上发生的链接数量(即一个节点拥有的关系数量)。度可以根据节点捕获流经网络的任何东西(例如病毒或某些信息)的直接风险来解释。在有向网络的情况下(其中联系有方向) ，我们通常定义两个独立的度量，即 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度 Outdegree&amp;lt;/font&amp;gt;'''。因此，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度indegree&amp;lt;/font&amp;gt;'''是指向该节点的关系数，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度outdegree&amp;lt;/font&amp;gt;'''是指该节点指向其他节点的关系数。当关系与一些积极的方面如友谊或合作有关时， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''通常被解释为一种形式的受欢迎，而 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度Indegree&amp;lt;/font&amp;gt;'''则被解释为合群。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
&lt;br /&gt;
The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
&lt;br /&gt;
对于给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边，度的中心性定义为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Calculating degree centrality for all the nodes in a graph takes [[big theta|&amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt;]] in a [[dense matrix|dense]] [[adjacency matrix]] representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a [[sparse matrix]] representation.&lt;br /&gt;
&lt;br /&gt;
Calculating degree centrality for all the nodes in a graph takes &amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt; in a dense adjacency matrix representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a sparse matrix representation.&lt;br /&gt;
&lt;br /&gt;
计算一个图中所有节点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''需要在图的稠密'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵Adjacency matrix &amp;lt;/font&amp;gt;'''表示中使用 Theta (v ^ 2) &amp;lt;/math &amp;gt; ，而在稀疏矩阵表示中使用 Theta (e) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of ''graph centralization''.&amp;lt;ref&amp;gt;Freeman, Linton C. &amp;quot;Centrality in social networks conceptual clarification.&amp;quot; Social networks 1.3 (1979): 215–239.&amp;lt;/ref&amp;gt; Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
&lt;br /&gt;
The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of graph centralization. Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
&lt;br /&gt;
节点级中心性的定义可以扩展到整个图，在这种情况下，我们指的是图的集中性。设 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 为 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''最高的节点。让 &amp;lt; math &amp;gt; x: = (y，z) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; | y | &amp;lt;/math &amp;gt; 节点连接图，最大化下列数量(&amp;lt; math &amp;gt; y * &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 中度最高的节点) :&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h = sum ^ { | y | }{ j = 1}[ c _ d (y *)-c _ d (y _ j)] &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
&lt;br /&gt;
Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
&lt;br /&gt;
相应地，图形 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''如下:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ h } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a [[star graph]]), and in this case&lt;br /&gt;
&lt;br /&gt;
The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a star graph), and in this case&lt;br /&gt;
&lt;br /&gt;
当图形 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 包含一个所有其他节点都连接的中心节点(一个星形图)时，&amp;lt; math &amp;gt; h &amp;lt;/math &amp;gt; 的值最大化，在这种情况下&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
(n-1)-1) = n ^ 2-3n + 2&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
所以，对于任意的图 &amp;lt; math &amp;gt; g: = (v，e) ，&amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ | v | ^ 2-3 | v | + 2} &amp;lt;/math &amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Closeness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Closeness centrality}}In a [[Connected component (graph theory)|connected]] [[Graph (discrete mathematics)|graph]], the [[Normalization (statistics)|normalized]] '''closeness centrality''' (or '''closeness''') of a node is the average length of the [[Shortest path problem|shortest path]] between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
&lt;br /&gt;
In a connected graph, the normalized closeness centrality (or closeness) of a node is the average length of the shortest path between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
&lt;br /&gt;
在连通图中，节点的标准'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''(或贴近性)是节点与图中所有其他节点之间最短路径的平均长度。因此，一个节点越是中心，它就越接近所有其他节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Closeness was defined by [[Alex Bavelas]] (1950) as the [[Multiplicative inverse|reciprocal]] of the '''farness''',&amp;lt;ref&amp;gt;Alex Bavelas. Communication patterns in task-oriented groups. ''J. Acoust. Soc. Am'', '''22'''(6):725–730, 1950.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;{{cite journal|year=1966|title=The centrality index of a graph|url=|journal=Psychometrika|volume=31|issue=4|pages=581–603|doi=10.1007/bf02289527|pmid=5232444|hdl=10338.dmlcz/101401|last1=Sabidussi|first1=G|hdl-access=free}}&amp;lt;/ref&amp;gt; that is:&lt;br /&gt;
&lt;br /&gt;
Closeness was defined by Alex Bavelas (1950) as the reciprocal of the farness, that is:&lt;br /&gt;
&lt;br /&gt;
亚历克斯 · 巴维拉斯(1950)将亲密度定义为相对于距离的倒数，即:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
C (x) = frac {1}{ sum _ y d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the [[Distance (graph theory)|distance]] between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the distance between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; d (y，x) &amp;lt;/math &amp;gt; 是顶点 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; 之间的距离。然而，当谈到'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''时，人们通常会提到它的标准化形式，一般是以前的公式乘以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; ，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。这种调整允许比较不同大小图形的节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Taking distances ''from'' or ''to'' all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in [[directed graph]]s (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
&lt;br /&gt;
Taking distances from or to all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in directed graphs (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
&lt;br /&gt;
从所有其他节点或到所有其他节点的距离在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 无向图Undirected graphs&amp;lt;/font&amp;gt;'''中是不相关的，但是在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 有向图Directed graphs&amp;lt;/font&amp;gt;'''中可能产生完全不同的结果(例如:一个网站可以从传出链接获得高的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，而从传入链接获得低的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''）。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
===Harmonic centrality===&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the '''harmonic centrality''' reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the harmonic centrality reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
在一个(不一定是连通的)图中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''反转了'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''定义中的和互反运算:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h (x) = sum { y neq x } frac {1}{ d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; 1/d (y，x) = 0 &amp;lt;/math &amp;gt; if there is no path from &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; to &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 。调和中心性可以通过除以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; 来标准化，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。&lt;br /&gt;
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Harmonic centrality was proposed by [[Massimo Marchiori|Marchiori]] and [[Vito Latora|Latora]] (2000)&amp;lt;ref name=&amp;quot;marchiorilatora2000&amp;quot;&amp;gt;{{citation| journal = Physica A: Statistical Mechanics and Its Applications  | last1 = Marchiori | first1 = Massimo | last2 = Latora | first2 = Vito | year = 2000 | volume = 285 | issue = 3–4 | pages = 539–546 | title = Harmony in the small-world | doi=10.1016/s0378-4371(00)00311-3| arxiv = cond-mat/0008357 | bibcode = 2000PhyA..285..539M }}&amp;lt;/ref&amp;gt; and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot;&amp;lt;ref&amp;gt;{{cite journal|first1=Anthony|last1=Dekker|title=Conceptual Distance in Social Network Analysis|journal=Journal of Social Structure|volume=6|issue=3|year=2005|url=http://www.cmu.edu/joss/content/articles/volume6/dekker/index.html}}&amp;lt;/ref&amp;gt; and by Rochat (2009).&amp;lt;ref&amp;gt;{{cite conference  | author = Yannick Rochat  | title = Closeness centrality extended to unconnected graphs: The harmonic centrality index | conference = Applications of Social Network Analysis, ASNA 2009 | url = http://infoscience.epfl.ch/record/200525/files/%5bEN%5dASNA09.pdf }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Harmonic centrality was proposed by Marchiori and Latora (2000) and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot; and by Rochat (2009).&lt;br /&gt;
&lt;br /&gt;
调和中心性是由 Marchiori 和 Latora (2000)提出的，然后是 Dekker (2005)独立提出的，使用的名称是“有价值的中心性” ，Rochat (2009)。&lt;br /&gt;
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==Betweenness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Betweenness centrality}}&lt;br /&gt;
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[[File:Graph betweenness.svg|240px|right|thumb|Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.]]&lt;br /&gt;
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Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.&lt;br /&gt;
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色调(从红色 = 0到蓝色 = max)表示节点之间的距离。&lt;br /&gt;
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'''Betweenness''' is a centrality measure of a [[vertex (graph theory)|vertex]] within a [[Graph (discrete mathematics)|graph]] (there is also [[edge (graph theory)|edge]] betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by [[Linton Freeman]]&amp;lt;ref name=&amp;quot;freeman1977&amp;quot;&amp;gt;{{cite journal |last1 = Freeman |first1 = Linton | year=1977| title = A set of measures of centrality based upon betweenness | journal = Sociometry| volume=40|issue = 1 | pages=35–41 | doi=10.2307/3033543|jstor = 3033543 }}&amp;lt;/ref&amp;gt; In his conception, vertices that have a high probability to occur on a randomly chosen [[shortest path problem|shortest path]] between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
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Betweenness is a centrality measure of a vertex within a graph (there is also edge betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by Linton Freeman In his conception, vertices that have a high probability to occur on a randomly chosen shortest path between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
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中介性是图中顶点的中心性度量(也有边中介性，这里没有讨论)。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''量化了一个节点沿着其他两个节点之间的最短路径充当桥梁的次数。在林顿 · 弗里曼的概念中，在两个随机选择的顶点之间随机选择的最短路径上出现概率高的顶点具有很高的中介性。&lt;br /&gt;
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The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
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The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
&lt;br /&gt;
在一个图 &amp;lt; math &amp;gt; g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的顶点之间的距离计算如下:&lt;br /&gt;
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# For each pair of vertices (''s'',''t''), compute the [[Shortest path problem|shortest paths]] between them.&lt;br /&gt;
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 For each pair of vertices (s,t), compute the shortest paths between them.&lt;br /&gt;
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对于每一对顶点(s，t) ，计算它们之间的最短路径。&lt;br /&gt;
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# For each pair of vertices (''s'',''t''), determine the fraction of shortest paths that pass through the vertex in question (here, vertex ''v'').&lt;br /&gt;
&lt;br /&gt;
 For each pair of vertices (s,t), determine the fraction of shortest paths that pass through the vertex in question (here, vertex v).&lt;br /&gt;
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对于每对顶点(s，t) ，确定通过该顶点(这里是顶点 v)的最短路径的分数。&lt;br /&gt;
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# Sum this fraction over all pairs of vertices (''s'',''t'').&lt;br /&gt;
&lt;br /&gt;
 Sum this fraction over all pairs of vertices (s,t).&lt;br /&gt;
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对所有顶点对(s，t)求这个分数的和。&lt;br /&gt;
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More compactly the betweenness can be represented as:&amp;lt;ref name=&amp;quot;brandes&amp;quot;&amp;gt;{{cite journal |last1 = Brandes |first1 = Ulrik | year=2001 |title = A faster algorithm for betweenness centrality  | journal = Journal of Mathematical Sociology| volume=25|issue = 2 | pages=163–177| url = http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.11.2024 | accessdate = October 11, 2011| format = PDF | doi=10.1080/0022250x.2001.9990249|citeseerx = 10.1.1.11.2024 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
More compactly the betweenness can be represented as:&lt;br /&gt;
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更确切地说，两者之间的关系可以表示为:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
{ math &amp;gt; c _ b (v) = sum _ { s neq v neq t in v } frac { sigma _ st }(v)}{ sigma _ st } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including ''v'', which for [[Digraph (mathematics)|directed graphs]] is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected [[Star (graph theory)|star graph]], the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including v, which for directed graphs is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected star graph, the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; sigma { st } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { st }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径数。有向图是 &amp;lt; math &amp;gt; (n-1)(n-2) &amp;lt;/math &amp;gt; ，无向图是 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; 。例如，在一个无向星图中，中心顶点(包含在每个可能的最短路径中)的中介性为 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; (1，如果标准化) ，而叶子(包含在没有最短路径中)的中介性为0。&lt;br /&gt;
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From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires [[Big O notation|&amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt;]] time with the [[Floyd–Warshall algorithm]]. However, on sparse graphs, [[Johnson's algorithm]] may be more efficient, taking [[Big O notation|&amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt;]] time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm&amp;lt;ref name=brandes/&amp;gt; which takes [[Big O notation|&amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt;]] time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&amp;lt;ref name=&amp;quot;brandes&amp;quot; /&amp;gt;&lt;br /&gt;
&lt;br /&gt;
From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires &amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt; time with the Floyd–Warshall algorithm. However, on sparse graphs, Johnson's algorithm may be more efficient, taking &amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt; time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm which takes &amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt; time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&lt;br /&gt;
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从计算的角度来看，图中所有顶点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介和紧密中心性Betweenness and Closeness centralities&amp;lt;/font&amp;gt;'''都涉及到计算图中所有顶点对之间的最短路径，这就需要用 Floyd-Warshall 算法计算时间。然而，对于稀疏图，约翰逊算法的效率可能更高，采用 &amp;lt; math &amp;gt; o (v ^ 2 log v + v e) &amp;lt;/math &amp;gt; 时间。在不加权图的情况下，可以用 Brandes 的算法进行计算，该算法需要 &amp;lt; math &amp;gt; o (v e) &amp;lt;/math &amp;gt; 时间。一般情况下，这些算法假定图是无向的，并且连通图中允许有圈和多条边。当专门处理网络图时，图通常没有环或多条边来维持简单的关系(其中的边表示两个人或顶点之间的联系)。在这种情况下，使用 Brandes 的算法将最终的中心性分数除以2来计算每条被重复计算的最短路径。&lt;br /&gt;
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==Eigenvector centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Eigenvector centrality}}&lt;br /&gt;
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'''Eigenvector centrality''' (also called '''eigencentrality''') is a measure of the influence of a [[node (networking)|node]] in a [[network (mathematics)|network]]. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&amp;lt;ref&amp;gt;{{cite journal|title = The mathematics of networks|url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf|author = M. E. J. Newman|accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;/&amp;gt; [[Google]]'s [[PageRank]] and the [[Katz centrality]] are variants of the eigenvector centrality.&amp;lt;ref name=&amp;quot;ams&amp;quot;&amp;gt;{{Cite web | url=http://www.ams.org/samplings/feature-column/fcarc-pagerank | title=American Mathematical Society}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Eigenvector centrality (also called eigencentrality) is a measure of the influence of a node in a network. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''(也称为特征中心性)是衡量网络中节点影响的一个指标。它将相对得分分配给网络中的所有节点，这是基于这样一个概念: 与得分较高的节点相比，与得分较低的节点相同的连接对所涉及的节点的得分贡献更大。&lt;br /&gt;
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=== Using the adjacency matrix to find eigenvector centrality ==&lt;br /&gt;
==使用'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''发现'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the [[adjacency matrix]], i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
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For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the adjacency matrix, i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
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对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 让 &amp;lt; math &amp;gt; a = (a { v，t }) &amp;lt;/math &amp;gt; 成为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''，即。如果顶点 &amp;lt; math &amp;gt; &amp;gt; v &amp;lt;/math &amp;gt; 与 math &amp;gt; t &amp;lt;/math &amp;gt; 相连，而 &amp;lt; math &amp;gt; a { v，t } = 0 &amp;lt;/math &amp;gt; 否则。顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分可以定义为:&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
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在 m (v)} x _ t = frac {1}{ lambda } sum { t in g } a { v，t } x _ t &amp;lt;/math &amp;gt; &lt;br /&gt;
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where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the [[eigenvector]] equation&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the eigenvector equation&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; m (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 和 &amp;lt; math &amp;gt; &amp;gt; lambda &amp;lt;/math &amp;gt; 的邻居集合。通过一个小的重新排列，这可以被重写成向量符号，作为特征向量方程&lt;br /&gt;
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:&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
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[ math &amp;gt; mathbf { Ax } = { lambda } mathbf { x } &amp;lt;/math &amp;gt; &lt;br /&gt;
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In general, there will be many different [[eigenvalue]]s &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the [[Perron–Frobenius theorem]]. This greatest eigenvalue results in the desired centrality measure.&amp;lt;ref&amp;gt;{{cite journal  | author = M. E. J. Newman  | title = The mathematics of networks  | url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf  | accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt; The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices ''n''. [[Power iteration]] is one of many [[eigenvalue algorithm]]s that may be used to find this dominant eigenvector.&amp;lt;ref name=&amp;quot;ams&amp;quot; /&amp;gt; Furthermore, this can be generalized so that the entries in ''A'' can be real numbers representing connection strengths, as in a [[stochastic matrix]].&lt;br /&gt;
&lt;br /&gt;
In general, there will be many different eigenvalues &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the Perron–Frobenius theorem. This greatest eigenvalue results in the desired centrality measure. The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices n. Power iteration is one of many eigenvalue algorithms that may be used to find this dominant eigenvector. Furthermore, this can be generalized so that the entries in A can be real numbers representing connection strengths, as in a stochastic matrix.&lt;br /&gt;
&lt;br /&gt;
一般情况下，存在许多不同的特征值，对于这些特征值存在一个非零特征向量解。由于邻接矩阵中的条目是非负的，所以由 Perron-弗罗贝尼乌斯定理得出，它有一个实的和正的唯一最大特征值。由这个最大的特征值得出期望的中心性度量。相关特征向量的 &amp;lt; math &amp;gt; v ^ { th } &amp;lt;/math &amp;gt; 分量给出了网络中顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分。特征向量只定义了一个公共因子，所以只有顶点中心的比例是明确定义的。要定义一个绝对分数，必须对特征向量进行标准化，例如，使所有顶点的和为1或顶点的总数n。此外，这可以通用，使得 a 中的条目可以是表示连接强度的真实数字，就像'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 随机矩阵Stochastic matrix&amp;lt;/font&amp;gt;'''中一样。&lt;br /&gt;
&lt;br /&gt;
==Katz centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Katz centrality}}&lt;br /&gt;
&lt;br /&gt;
'''Katz centrality'''&amp;lt;ref&amp;gt;Katz, L. 1953. A New Status Index Derived from Sociometric Index. Psychometrika, 39–43.&amp;lt;/ref&amp;gt; is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
Katz centrality is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''是度中心性的推广。度中心性度量的是直接邻居的数量，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''度量的是通过一条路径可以连接的所有节点的数量，而远处节点的贡献会受到'''&amp;lt;font color=&amp;quot;#32CD32&amp;quot;&amp;gt; '削弱（惩罚？）Penalized&amp;lt;/font&amp;gt;''。在数学上，它被定义为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[数学][数学]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; (0,1) &amp;lt;/math &amp;gt; 中的衰减因子。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
&lt;br /&gt;
Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''可以看作是特征向量中心性的变体。Katz 中心性的另一种形式是&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
(x _ j + 1) &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
与特征向量中心性的表达式相比，&amp;lt; math &amp;gt; x _ j &amp;lt;/math &amp;gt; 被 &amp;lt; math &amp;gt; x _ j + 1所代替&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
It is shown that&amp;lt;ref&amp;gt;{{cite journal | last1 = Bonacich | first1 = P | year = 1991 | title = Simultaneous group and individual centralities | url = | journal = Social Networks | volume = 13 | issue = 2| pages = 155–168 | doi=10.1016/0378-8733(91)90018-o}}&amp;lt;/ref&amp;gt; the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
&lt;br /&gt;
It is shown that the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
&lt;br /&gt;
结果表明，主特征向量(与 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; ，邻接矩阵的最大特征值相关)是 Katz 中心性的极限，因为 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 接近 &amp;lt; math &amp;gt; tfrac {1}{ lambda } &amp;lt;/math &amp;gt; 。&lt;br /&gt;
&lt;br /&gt;
== PageRank centrality ==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页分布中心性PageRank&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
{{main|PageRank}}'''[[PageRank]]''' satisfies the following equation&lt;br /&gt;
&lt;br /&gt;
PageRank satisfies the following equation&lt;br /&gt;
&lt;br /&gt;
PageRank满足下面的等式&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1-alpha { n } ，&amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
其中&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[ math &amp;gt; l (j) = sum { i } a { ji } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&amp;lt;ref&amp;gt;[http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf How does Google rank webpages?] {{webarchive | url= https://web.archive.org/web/20120131083328/http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf |date=January 31, 2012 }} 20Q: About Networked Life&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&lt;br /&gt;
&lt;br /&gt;
是节点 &amp;lt; math &amp;gt; j &amp;lt;/math &amp;gt; (或有向图中出站链接的数量)的邻居数量。与特征向量中心性和 Katz 中心性相比，尺度因子 &amp;lt; math &amp;gt; l (j) &amp;lt;/math &amp;gt; 是一个主要的区别。PageRank 和特征向量中心性的另一个区别是 PageRank 向量是一个左手特征向量(注意因子 &amp;lt; math &amp;gt; a _ { ji } &amp;lt;/math &amp;gt; 具有相反的索引)。&lt;br /&gt;
&lt;br /&gt;
==Percolation centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&amp;lt;ref name=&amp;quot;piraveenan2013&amp;quot;&amp;gt;{{cite journal |last1 = Piraveenan |first1 = M. |last2 = Prokopenko |first2 = M.|last3 = Hossain|first3 = L. |year=2013| title = Percolation Centrality: Quantifying Graph-Theoretic Impact of Nodes during Percolation in Networks | journal = PLOS One | volume=8 | issue=1 | doi=10.1371/journal.pone.0053095 | pages=e53095 | pmid=23349699 | pmc=3551907| bibcode=2013PLoSO...853095P }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&lt;br /&gt;
&lt;br /&gt;
在复杂网络中，存在大量的中心性度量来确定单个节点的“重要性”。然而，这些度量单纯从拓扑学的角度来量化节点的重要性，节点的值并不以任何方式依赖于节点的状态。不管网络动态如何，它都保持不变。即使对于加权的两者之间的度量也是如此。然而，一个节点可能很好地位于'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''或其他中心性度量的中心位置，但可能不是位于有过滤的网络的上下文中的中心位置。在许多情况下，复杂网络中都会出现“传染”现象。例如，病毒或细菌感染可以通过人们的社交网络传播，也就是所谓的接触网络。还可以在更高的抽象层次上考虑疾病的传播问题，设想通过公路、铁路或空中连接起来的城镇或人口中心网络。计算机病毒可以通过计算机网络传播。关于商业活动和交易的谣言或新闻也可以通过人们的社交网络传播。在所有这些情况下，一种“传染病”在一个复杂网络的链接上传播，随着它的传播，无论是可恢复的还是不可恢复的，都会改变节点的“状态”。例如，在流行病学方案中，随着感染扩散，个人从”易感”状态转变为”受感染”状态。在上面的例子中，随着传染的扩散，每个节点可以采取的状态可以是二进制的(例如接收/没有接收到一条新闻)、离散的(易感/受感染/康复) ，甚至是连续的(例如一个城镇中受感染的人的比例) 。这些情景的共同特点是，传染的扩散导致网络中节点状态的改变。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''（PC)就是基于这个思想而提出的，它特别地衡量了节点在协助网络渗滤方面的重要性。这项措施是由 piraveanan 等人提出的。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
'''Percolation centrality''' is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
&lt;br /&gt;
Percolation centrality is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''定义为在给定时间内一个给定节点的过滤路径的比例。“渗滤路径”是一对节点之间的最短路径，其中源节点被渗滤(例如，被感染)。目标节点可以是过滤的或非过滤的，或处于部分过滤状态。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; PC ^ t (v) = frac {1}{ N-2} sum { s neq v neq r } frac { sigma { sr }(v)}{ sigma { sr }} frac { x ^ t }{ sum {[{ x ^ t } i }}}]}}-{ x ^ t }{ v } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; σ { sr } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; r &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { sr }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径的总数。在时间 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 时，节点的过滤状态用 &amp;lt; math &amp;gt; { x ^ t } _ i &amp;lt;/math &amp;gt; 表示，两个特殊情况是当 &amp;lt; math &amp;gt; { x ^ t } _ i = 0 &amp;lt;/math &amp;gt; 表示在时间上是非过滤状态，而当 &amp;lt; math &amp;gt; &amp;lt; x ^ t &amp;lt;/math &amp;gt; i = 1 &amp;lt;/math &amp;gt; 表示在时间上是完全过滤状态。两者之间的值表示部分过滤状态(例如，在一个城镇网络中，这是该城镇感染者的百分比)。&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in [[Big O notation|&amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt;]] time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is [[Big O notation|&amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;]].&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in &amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt; time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is &amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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渗流路径的权重取决于分配给源节点的渗流水平，前提是源节点的渗流水平越高，源节点的路径就越重要。因此，位于源自高渗滤节点的最短路径上的节点可能对渗滤更为重要。PC 的定义也可以扩展到包括目标节点的权重。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''计算运行在 &amp;lt; math &amp;gt; o (NM) &amp;lt;/math &amp;gt; 时间，采用了 Brandes 快速算法的有效实现，如果计算需要考虑目标节点的权重，最坏情况下时间为 &amp;lt; math &amp;gt; o (n ^ 3) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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==Cross-clique centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 交叉团中心性Cross-clique centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
'''Cross-clique centrality''' of a single node in a complex graph determines the connectivity of a node to different [[clique (graph theory)|clique]]s. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in &amp;lt;ref name=&amp;quot;xssworms&amp;quot;&amp;gt;{{cite journal |last1 = Faghani|first1 = Mohamamd Reza| year=2013| title = A Study of XSS Worm Propagation and Detection Mechanisms in Online Social Networks | journal = IEEE Transactions on Information Forensics and Security|volume = 8|issue = 11|pages = 1815–1826|doi = 10.1109/TIFS.2013.2280884}}&amp;lt;/ref&amp;gt; but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
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Cross-clique centrality of a single node in a complex graph determines the connectivity of a node to different cliques. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in  but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
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复杂图中单个节点的跨团中心性决定了一个节点与不同团的连通性。具有高度跨团连通性的节点有利于信息或疾病在图中的传播。团是一种'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图Subgraphs&amp;lt;/font&amp;gt;'''，团中的每个节点都与团中的其他节点相连。对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边的交叉团连通性，定义为 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; x (v) &amp;lt;/math &amp;gt; 其中 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 所属的顶点团数。这个测度应用日久，但是在1998年由 Everett 和 Borgatti 首次提出，他们称之为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 派系重叠中心性Clique-overlap centrality&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Freeman centralization==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心度Freeman centralization&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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The '''centralization''' of any network is a measure of how central its most central node is in relation to how central all the other nodes are.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;&amp;gt;{{citation | journal = Social Networks | last1 = Freeman | first1 = Linton C. | year = 1979 | volume = 1 | issue = 3 | pages = 215–239 | title = centrality in social networks: Conceptual clarification | url = http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | doi = 10.1016/0378-8733(78)90021-7 | citeseerx = 10.1.1.227.9549 | access-date = 2014-07-31 | archive-url = https://web.archive.org/web/20160222033108/http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | archive-date = 2016-02-22 | url-status = dead }}&amp;lt;/ref&amp;gt; Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
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The centralization of any network is a measure of how central its most central node is in relation to how central all the other nodes are. Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
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任何网络的集中度都是衡量其最核心的节点相对于其他所有节点的集聚程度的标准。集中度的度量方法是: (a)计算网络中最中心的节点与所有其他节点之间的中心性差异之和; (b)将这个数量除以理论上相同规模的任何网络中这种差异之和的最大值。因此，每个中心性度量都可以有自己的集中性度量。正式定义，如果 &amp;lt; math &amp;gt; c _ x (p _ i) &amp;lt;/math &amp;gt; 是点 &amp;lt; math &amp;gt; i &amp;lt;/math &amp;gt; 的中心性度量，如果 &amp;lt; math &amp;gt; c _ x (p _ *) &amp;lt;/math &amp;gt; 是网络中最大的中心性度量，如果:&lt;br /&gt;
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:&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; max sum { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i) &amp;lt;/math &amp;gt; &lt;br /&gt;
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is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;&lt;br /&gt;
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is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&lt;br /&gt;
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对于任何具有相同节点数的图来说，点中心性的最大差异是:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; c _ x = frac { sum _ { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i)}{ max sum _ { i = 1 ^ { n } c _ x (p _ *)-c _ x (p _ i)} . &amp;lt;/math &amp;gt;&lt;br /&gt;
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== Dissimilarity based centrality measures ==&lt;br /&gt;
==基于相异性的中心性度量==&lt;br /&gt;
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[[File:Srep17095-f1.jpg|thumbnail|In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.]]&lt;br /&gt;
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In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.&lt;br /&gt;
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在图示的网络中，绿色节点和红色节点最不相似，因为它们之间不共享相邻节点。因此，绿色的节点比灰色的节点对中心性的贡献更大，因为红色的节点只能通过绿色访问蓝色的节点，而灰色的节点对于红色的节点是多余的，因为它可以直接访问每个灰色的节点，而不需要任何中介。&lt;br /&gt;
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In order to obtain better results in the ranking of the nodes of a given network,  in &amp;lt;ref&amp;gt;{{Cite journal|title = Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|journal = Scientific Reports|date = 2015-11-25|pmc = 4658528|pmid = 26603652|volume = 5|doi = 10.1038/srep17095|first = A. J.|last = Alvarez-Socorro|first2 = G. C.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz|pages=17095|bibcode = 2015NatSR...517095A}}&amp;lt;/ref&amp;gt; are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with [[eigenvector centrality]], calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
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In order to obtain better results in the ranking of the nodes of a given network,  in  are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with eigenvector centrality, calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
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为了在给定网络节点的排序中获得更好的结果，在复杂网络中使用了相异性度量(特定于分类和数据挖掘理论)来丰富中心性度量。特征向量中心性通过求解特征值问题来计算每个节点的中心性&lt;br /&gt;
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:&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
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数学，数学&lt;br /&gt;
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where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary [[Matrix similarity|dissimilarity]] matrix, defined through a dissimilitary measure, e.g., [[Jaccard index|Jaccard]] dissimilarity given by&lt;br /&gt;
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where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary dissimilarity matrix, defined through a dissimilitary measure, e.g., Jaccard dissimilarity given by&lt;br /&gt;
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这里 &amp;lt; math &amp;gt; w { ij } = a { ij } d { ij } &amp;lt;/math &amp;gt; (coordinate-to-coordinate product)和 &amp;lt; math &amp;gt; d { ij } &amp;lt;/math &amp;gt; 是一个任意的不相似矩阵，通过一个双重军事度量来定义，例如，Jaccard 由&lt;br /&gt;
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:&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
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1-dfrac { | v ^ { + }(i) cap v ^ { + }(j) | }{ | v ^ { + }(i) cup v ^ { + }(j) | } &amp;lt;/math &amp;gt; &lt;br /&gt;
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Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
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Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
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这种度量允许我们量化每个节点对给定节点中心性的拓扑贡献(这就是为什么我们称之为贡献中心性) ，对那些相异性较大的节点有更多的权重/相关性，因为这些节点允许给定的节点访问那些它们自己不能直接访问的节点。&lt;br /&gt;
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Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the [[Perron–Frobenius theorem]] to ensure that the above problem has a unique solution for ''λ'' = ''λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt;'' with '''c''' non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
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Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the Perron–Frobenius theorem to ensure that the above problem has a unique solution for λ = λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt; with c non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
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值得注意的是，&amp;lt; math &amp;gt; w &amp;lt;/math &amp;gt; 是非负的，因为 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; d &amp;lt;/math &amp;gt; 都是非负矩阵，所以我们可以使用 Perron 弗罗贝尼乌斯定理来确保上述问题对于 c 非负的 = &amp;lt; sub &amp;gt; max &amp;lt;/sub &amp;gt; 有唯一的解，这样我们就可以推断出网络中每个节点的中心性。因此，i-th 节点的中心性为&lt;br /&gt;
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:&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
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1{ n } sum { j = 1} ^ { n } w { ij } c { j } ，，，，，j = 1，cdots，n &amp;lt;/math &amp;gt; &lt;br /&gt;
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&lt;br /&gt;
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where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in &amp;lt;ref&amp;gt;{{Cite web|url = http://www.nature.com/article-assets/npg/srep/2015/151125/srep17095/extref/srep17095-s1.pdf|title = Supplementary Information for Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|date = |website = |publisher = Nature Publishing Group|last = Alvarez-Socorro|first = A.J.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz}}&amp;lt;/ref&amp;gt; obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in  obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是网络中的节点数。几个不同的措施和网络进行了测试，以获得在研究案例的改善的结果。&lt;br /&gt;
&lt;br /&gt;
==Extensions==&lt;br /&gt;
==扩展==&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality&amp;lt;ref&amp;gt;{{cite journal | last1 = Braha | first1 = D. | last2 = Bar-Yam | first2 = Y. | year = 2006 | title = From Centrality to Temporary Fame: Dynamic Centrality in Complex Networks | url = | journal = Complexity | volume = 12 | issue = 2| pages = 59–63 | doi=10.1002/cplx.20156| arxiv = physics/0611295 | bibcode = 2006Cmplx..12b..59B }}&amp;lt;/ref&amp;gt; in the context of time-dependent and temporal networks.&amp;lt;ref&amp;gt;{{cite journal | last1 = Hill | first1 = S.A. | last2 = Braha | first2 = D. | year = 2010 | title = Dynamic Model of Time-Dependent Complex Networks | url = | journal = Physical Review E | volume = 82 | issue = 4| page = 046105 | doi=10.1103/physreve.82.046105| pmid = 21230343 | arxiv = 0901.4407 | bibcode = 2010PhRvE..82d6105H }}&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Gross, T. and Sayama, H. (Eds.). 2009. ''Adaptive Networks: Theory, Models and Applications.'' Springer.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Holme, P. and Saramäki, J. 2013. ''Temporal Networks.'' Springer.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality in the context of time-dependent and temporal networks.&lt;br /&gt;
&lt;br /&gt;
经验和理论研究已经将静态网络中的中心性概念扩展到时间依赖网络和时间网络中的动态中心性。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&amp;lt;ref&amp;gt;{{cite journal | last1 = Opsahl | first1 = Tore | last2 = Agneessens | first2 = Filip | last3 = Skvoretz | first3 = John | title = Node centrality in weighted networks: Generalizing degree and shortest paths | doi = 10.1016/j.socnet.2010.03.006 | year = 2010 | pages = 245–251 | volume = 32 | journal = Social Networks | url = http://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | issue = 3 | access-date = 2010-04-23 | archive-url = https://web.archive.org/web/20180226080331/https://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | archive-date = 2018-02-26 | url-status = dead }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&lt;br /&gt;
&lt;br /&gt;
对加权网络的推广，见 Opsahl 等人。(2010).&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, '''group betweenness''' centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&amp;lt;ref name=&amp;quot;group1&amp;quot;&amp;gt;Everett, M. G. and Borgatti, S. P. (2005). Extending centrality. In P. J. Carrington, J. Scott and S. Wasserman (Eds.), ''Models and methods in social network analysis'' (pp. 57–76). New York: Cambridge University Press.&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;group2&amp;quot;&amp;gt;Puzis, R., Yagil, D., Elovici, Y., Braha, D. (2009).[http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf Collaborative attack on Internet users’ anonymity] {{Webarchive|url=https://web.archive.org/web/20131207133417/http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf |date=2013-12-07 }}, ''Internet Research'' '''19'''(1)&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, group betweenness centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&lt;br /&gt;
&lt;br /&gt;
中心性的概念也扩展到了群体层次。例如，组间的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''显示了连接穿过组的成对非组成员的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Geodesics &amp;lt;/font&amp;gt;'''的比例。&lt;br /&gt;
&lt;br /&gt;
==See also==&lt;br /&gt;
==又及==&lt;br /&gt;
* [[Alpha centrality]]&lt;br /&gt;
&lt;br /&gt;
* [[Core–periphery structure]]&lt;br /&gt;
&lt;br /&gt;
* [[Distance (graph theory)|Distance in graphs]]&lt;br /&gt;
&lt;br /&gt;
*阿尔法中心性&lt;br /&gt;
&lt;br /&gt;
*核心—外围结构&lt;br /&gt;
&lt;br /&gt;
*距离（图理论）图中的距离&lt;br /&gt;
&lt;br /&gt;
==Notes and references==&lt;br /&gt;
&lt;br /&gt;
{{Reflist}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Further reading==&lt;br /&gt;
拓展阅读&lt;br /&gt;
* Koschützki, D.; Lehmann, K. A.; Peeters, L.; Richter, S.; Tenfelde-Podehl, D. and Zlotowski, O. (2005) Centrality Indices. In Brandes, U. and Erlebach, T. (Eds.)  ''Network Analysis: Methodological Foundations'', pp.&amp;amp;nbsp;16–61, LNCS 3418, Springer-Verlag.&lt;br /&gt;
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[[Category:Graph theory]]&lt;br /&gt;
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Category:Graph theory&lt;br /&gt;
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分类: 图论&lt;br /&gt;
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[[Category:Graph algorithms]]&lt;br /&gt;
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Category:Graph algorithms&lt;br /&gt;
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分类: 图形算法&lt;br /&gt;
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[[Category:Algebraic graph theory]]&lt;br /&gt;
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Category:Algebraic graph theory&lt;br /&gt;
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分类: 代数图论&lt;br /&gt;
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[[Category:Networks]]&lt;br /&gt;
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Category:Networks&lt;br /&gt;
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分类: 网络&lt;br /&gt;
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[[Category:Network analysis]]&lt;br /&gt;
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Category:Network analysis&lt;br /&gt;
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分类: 网络分析&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Centrality]]. Its edit history can be viewed at [[网络中心性/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E7%BD%91%E7%BB%9C%E4%B8%AD%E5%BF%83%E6%80%A7&amp;diff=19881</id>
		<title>网络中心性</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E7%BD%91%E7%BB%9C%E4%B8%AD%E5%BF%83%E6%80%A7&amp;diff=19881"/>
		<updated>2020-12-10T07:28:48Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* =网络流特征Characterization by network flows */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;此词条暂由水流心不竞初译，未经审校，带来阅读不便，请见谅。&lt;br /&gt;
&lt;br /&gt;
{{for|the statistical concept|Central tendency}}&lt;br /&gt;
{{Network Science}}&lt;br /&gt;
&lt;br /&gt;
In [[graph theory]] and [[network theory|network analysis]], indicators of '''centrality''' identify the most important [[vertex (graph theory)|vertices]] within a graph. Applications include identifying the most influential person(s) in a [[social network]], key infrastructure nodes in the [[Internet]] or [[urban network]]s, and [[super-spreader]]s of disease. Centrality concepts were first developed in [[social network analysis]], and many of the terms used to measure centrality reflect their [[sociology|sociological]] origin.&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
In graph theory and network analysis, indicators of centrality identify the most important vertices within a graph. Applications include identifying the most influential person(s) in a social network, key infrastructure nodes in the Internet or urban networks, and super-spreaders of disease. Centrality concepts were first developed in , and many of the terms used to measure centrality reflect their sociological origin.&lt;br /&gt;
&lt;br /&gt;
They should not be confused with [[node influence metric]]s, which seek to quantify the influence of every node in the network.&lt;br /&gt;
&lt;br /&gt;
They should not be confused with node influence metrics, which seek to quantify the influence of every node in the network.&lt;br /&gt;
&lt;br /&gt;
在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;图论 graph theory &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络分析 network analysis &amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性 centrality &amp;lt;/font&amp;gt;'''指标用于识别图中最重要的顶点。其应用包括在社会网络中识别出最有影响力的个人，在因特网或城市网络中识别出最为关键的基础设施节点，以及识别疾病的超级传播者。中心性的概念最初由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;社会网络分析 social network analysis&amp;lt;/font&amp;gt;'''所发展，因此许多用于衡量中心性的术语都反映出了它们的社会学出身。&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;中心性不应与节点影响度相混淆，后者意在量化网络中每个节点的影响。&lt;br /&gt;
&lt;br /&gt;
==中心性指数的定义与特性Definition and characterization of centrality indices==&lt;br /&gt;
&lt;br /&gt;
Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性指数 centrality indices&amp;lt;/font&amp;gt;'''旨在探寻如何描绘重要节点这一问题。这一问题的答案通常实值函数的形式给出，可根据函数值将图中各节点进行排序，进而确定最为重要的节点。&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
&lt;br /&gt;
The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
&lt;br /&gt;
“重要性”的含义十分广泛，因此导致了许多不同的中心性定义方式，我们可以将各种不同的定义方式划分为如下两类。&lt;br /&gt;
&lt;br /&gt;
&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important.&amp;lt;ref name=Borgatti2005/&amp;gt; &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt; Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important. &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&lt;br /&gt;
&lt;br /&gt;
“重要性”可以被设想为与网络中的某种流动或传输有关。&amp;lt;ref name=Borgatti2005/&amp;gt; “重要性”也可以被设想为与网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;内聚力 cohesiveness&amp;lt;/font&amp;gt;'''有关。这允许我们根据内聚力的不同测量方式对中心性予以分类。&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;这些方法将中心性划分于完全不同的类别中，也就是在一种类别中的中心性往往无法适用于其他类别。&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one ([[Centrality#Degree centrality|degree centrality]]) to infinite walks ([[Centrality#Eigenvector centrality|eigenvalue centrality]]).&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=&amp;quot;Benzi2013&amp;quot;&amp;gt;{{cite journal | last1=Benzi | first1=Michele | last2=Klymko| first2=Christine | year=2013 |title= A matrix analysis of different centrality measures |arxiv=1312.6722 | doi=10.1137/130950550 | volume=36 | issue=2 | journal=SIAM Journal on Matrix Analysis and Applications | pages=686–706}}&amp;lt;/ref&amp;gt; The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
&lt;br /&gt;
When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one (degree centrality) to infinite walks (eigenvalue centrality). The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
&lt;br /&gt;
当根据内聚力方法对中心性进行分类时，很明显大多数中心性都将被划分于同一类别。起始于给定顶点的步数总和仅取决于步数的定义以及计数方式。这种分类方式的不足表现为它仅能较弱的描绘中心性特征，即按照一步步度（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;度中心性 degree centrality&amp;lt;/font&amp;gt;'''）到无穷步步长（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 eigenvalue centrality&amp;lt;/font&amp;gt;'''）的方式将中心性置于一种光谱状的分类中。&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=&amp;quot;Benzi2013&amp;quot;&amp;gt;{{cite journal | last1=Benzi | first1=Michele | last2=Klymko| first2=Christine | year=2013 |title= A matrix analysis of different centrality measures |arxiv=1312.6722 | doi=10.1137/130950550 | volume=36 | issue=2 | journal=SIAM Journal on Matrix Analysis and Applications | pages=686–706}}&amp;lt;/ref&amp;gt; 对于采用类似方式定义的各种中心性的观察也表明了这些指数之间的高阶相关性。&lt;br /&gt;
&lt;br /&gt;
==网络流特征Characterization by network flows==&lt;br /&gt;
&lt;br /&gt;
A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at once.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at oe.&lt;br /&gt;
&lt;br /&gt;
一个网络可以被看成是对某种物体流动的路径描述。使基于流的类型和由中心性编码的路径类型（同时）得到表征。一个流可以基于传输，每个不可分割的项目从一个节点到另一个节点，就像一个包裹从配送站送到客户的房子。第二种情况是串行复制，在这种情况下，一个项从源节点被复制到达目标节点。例如通过流言传播信息，以私有方式传播信息，并在流程结束时通知源节点和目标节点。最后一种情况是并行复制，即同时将项目复制到多个链接，就像无线电广播一次性向多个听众提供相同的信息。&lt;br /&gt;
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Likewise, the type of path can be constrained to [[Distance (graph theory)|geodesics]] (shortest paths), [[Glossary of graph theory terms#path|paths]]  (no vertex is visited more than once), [[Glossary of graph theory terms#trail|trails]] (vertices can be visited multiple times, no edge is traversed more than once), or [[Glossary of graph theory terms#walk|walks]] (vertices and edges can be visited/traversed multiple times).&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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Likewise, the type of path can be constrained to geodesics (shortest paths), paths  (no vertex is visited more than once), trails (vertices can be visited multiple times, no edge is traversed more than once), or walks (vertices and edges can be visited/traversed multiple times).&lt;br /&gt;
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同样，路径类型可以被限定为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Distance &amp;lt;/font&amp;gt;'''(最短路径)、路径(对顶点的访问不超过一次)、小径(可以访问多次顶点，没有边被访问超过一次)或者步子(可以访问/遍历多次顶点和边)。&lt;br /&gt;
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===行走结构特征Characterization by walk structure===&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either ''radial'' or ''medial.'' Radial centralities count walks which start/end from the given vertex. The [[Centrality#Degree centrality|degree]] and [[Centrality#Eigenvector centrality|eigenvalue]] centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's [[Centrality#Betweenness centrality|betweenness]] centrality, the number of shortest paths which pass through the given vertex.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either radial or medial. Radial centralities count walks which start/end from the given vertex. The degree and eigenvalue centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's betweenness centrality, the number of shortest paths which pass through the given vertex.&lt;br /&gt;
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可以从中心性的构造方式推导出另一种分类方法。这又分成了两个类。中心点可以是放射状的，也可以是内侧的。从给定顶点开始/结束的径向中心点数。度和特征值中心是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 径向中心Radial centralities&amp;lt;/font&amp;gt;'''的例子，计算长度为一或无穷大的行走的个数。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中间中心性Medial centralities&amp;lt;/font&amp;gt;'''计算通过给定顶点的步数。典型的例子是 弗里曼的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality,&amp;lt;/font&amp;gt;'''，即穿过给定顶点的最短路径的数量。&lt;br /&gt;
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Likewise, the counting can capture either the ''volume'' or the ''length'' of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's [[Centrality#Closeness centrality|closeness]] centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example.&amp;lt;ref name=Borgatti2006/&amp;gt; Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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Likewise, the counting can capture either the volume or the length of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's closeness centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example. Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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同样地，计数可以抓住行走的体积或长度。体积是给定类型的行走的总数。上一段的三个例子就属于这一类。长度则给出从给定顶点到图中其余顶点的距离。弗里曼 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，即从一个给定顶点到所有其他顶点的测地距离，是最著名的例子。请注意，这种分类独立于步行计数的类型(即：步行，小道，路径，测地线)。&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&lt;br /&gt;
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博尔加蒂和埃弗雷特提出，这种类型学为如何最好地比较中心性度量提出了建议。在这个22分类中，放在同一盒子中的中心点足够相似，可以做出合理的选择; 人们可以合理地比较哪个对于给定的应用更好。然而，不同盒子中的度量方法是截然不同的。只有在预先确定哪个类别更适用的情况下，对相对适应性的评估才会发生，这使得比较变得毫无意义。&lt;br /&gt;
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===光谱上存在的径向体积中心Radial-volume centralities exist on a spectrum===&lt;br /&gt;
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The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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步行结构的特征表明，几乎所有广泛使用的中心性都是径向体积的衡量。这得出结论顶点的中心性是与之相关联的顶点中心性的函数。中心性根据如何定义关联而不同。&lt;br /&gt;
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Bonacich showed that if association is defined in terms of [[Glossary of graph theory terms#walk|walks]], then a family of centralities can be defined based on the length of walk considered.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;/&amp;gt; [[Centrality#Degree centrality|Degree centrality]] counts walks of length one, while [[Centrality#Eigenvector centrality|eigenvalue centrality]] counts walks of length infinity. Alternative definitions of association are also reasonable. [[Alpha centrality]] allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich showed that if association is defined in terms of walks, then a family of centralities can be defined based on the length of walk considered. Degree centrality counts walks of length one, while eigenvalue centrality counts walks of length infinity. Alternative definitions of association are also reasonable. Alpha centrality allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich 指出，如果联想是根据行走来定义的，那么可以根据考虑的行走长度来定义一个中心性家族。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''计算长度为1的行走，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征值中心性Eigenvalue centrality  &amp;lt;/font&amp;gt;'''计算长度为无穷大的行走。关联的其他定义也是合理的。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 阿尔法中心性Alpha centrality&amp;lt;/font&amp;gt;'''允许顶点有一个外部影响源。埃斯特拉达的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图中心性Subgraph centrality &amp;lt;/font&amp;gt;'''提出只计算封闭路径(三角形、正方形等)。).&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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这些测量方法的核心是这种现象：图中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵&amp;lt;/font&amp;gt;'''的幂给出了由该幂给出的散步长度的数目。同样，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 矩阵指数Matrix exponential&amp;lt;/font&amp;gt;'''也与给定长度的行走次数密切相关。邻接矩阵的初始转换允许对步行计数的类型进行不同的定义。无论采用哪种方法，顶点的中心性都可以表示为无穷和&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum _ { k = 0} ^ infty a _ { r } ^ { k } beta ^ k &amp;lt;/math &amp;gt; &lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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矩阵能量或者&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum { k = 0} ^ infty frac {(a _ r beta) ^ k }{ k！{/math &amp;gt; &lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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对于矩阵指数函数，其中&lt;br /&gt;
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* &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; is walk length,&lt;br /&gt;
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* &amp;lt;math&amp;gt;A_R&amp;lt;/math&amp;gt; is the transformed adjacency matrix, and&lt;br /&gt;
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* &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; is a discount parameter which ensures convergence of the sum.&lt;br /&gt;
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K为步长，A_R是邻接矩阵的转秩，贝达是保证收敛的折扣参数。&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. [[Alpha centrality]] replaces the adjacency matrix with its [[resolvent formalism|resolvent]]. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to [[Centrality#Degree centrality|degree centrality]]. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to [[Centrality#Eigenvector centrality|eigenvalue centrality]].&amp;lt;ref name=Benzi2013/&amp;gt;&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. Alpha centrality replaces the adjacency matrix with its resolvent. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to degree centrality. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to eigenvalue centrality.&lt;br /&gt;
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博纳奇的一系列措施并没有改变邻接矩阵。阿尔法集中性用它的解决方案替代了邻接矩阵。子图集中性用它的踪迹取代了邻接矩阵。一个令人吃惊的结论是，不管邻接矩阵最初的转变是什么，所有这些方法都有共同的限制行为。随着贝塔系数趋近于零，指数收敛到度中心性。随着贝塔系数接近其最大值，指数收敛到特征值的中心性。&lt;br /&gt;
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===博弈论中心性Game-theoretic centrality===&lt;br /&gt;
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The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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上述大多数标准措施的共同特点是，它们通过只关注一个节点本身所扮演的角色来评估确定节点的重要性。然而, 在许多应用中，这种方法是不充分的，因为可能会发生协同作用&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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如果将节点的功能分组考虑。&lt;br /&gt;
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[[File:Game-theoretic centrality.png|Example of game-theoretic centrality]]&lt;br /&gt;
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Example of game-theoretic centrality&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''的例子&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in &amp;lt;ref&amp;gt;Michalak, Aadithya, Szczepański, Ravindran, &amp;amp; Jennings {{ArXiv|1402.0567}}&amp;lt;/ref&amp;gt; uses the [[Shapley value]]. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in  uses the Shapley value. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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例如，考虑阻止流行病的问题。看看上面的网络图像，我们应该给哪些节点接种疫苗？基于前面描述的措施，我们希望识别在疾病传播中最重要的节点。仅仅基于中心的方法，即关注节点的个别特性，可能不是一个好主意。红色方块中的节点，单独不能阻止疾病的传播，但把它们作为一个群体来考虑，我们清楚地看到，如果疾病在节点 &amp;lt; math &amp;gt; v _ 1 &amp;lt;/math &amp;gt; 、 &amp;lt; math &amp;gt; v _ 4 &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; v _ 5 &amp;lt;/math &amp;gt; 中开始，它们就能阻止疾病的传播。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''试图利用博弈论中的工具来研究所描述的问题和机会。本文提出的方法使用了 Shapley 值。由于 Shapley 值计算的时间复杂性，这一领域的大部分工作都集中在实现新的算法和方法，这些算法和方法依赖于网络的特殊拓扑结构或问题的特殊性质。这种方法可以将时间复杂度从指数级降低到多项式级。&lt;br /&gt;
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Similarly, the solution concept [[authority distribution]] (&amp;lt;ref&amp;gt;{{cite journal |last=Hu |first=Xingwei |first2=Lloyd |last2=Shapley |title=On Authority Distributions in Organizations |journal=Games and Economic Behavior |volume=45 |pages=132–170 |year=2003 | doi = 10.1016/s0899-8256(03)00130-1 }}&amp;lt;/ref&amp;gt;) applies the [[Shapley-Shubik power index]], rather than the [[Shapley value]], to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020)&amp;lt;ref&amp;gt;{{cite journal|last=Hu|first=Xingwei|year=2020|volume=7|title=Sorting big data by revealed preference with application to college ranking |journal=Journal of Big Data|doi=10.1186/s40537-020-00300-1|doi-access=free}}&amp;lt;/ref&amp;gt;, such as ranking U.S. colleges.&lt;br /&gt;
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Similarly, the solution concept authority distribution () applies the Shapley-Shubik power index, rather than the Shapley value, to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020), such as ranking U.S. colleges.&lt;br /&gt;
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同样，'''&amp;lt;font color=&amp;quot;#CD32CD&amp;quot;&amp;gt; 加权分布概念的解()The solution concept authority distribution () &amp;lt;/font&amp;gt;'''采用 Shapley-Shubik 幂指数，而不是 Shapley 值来衡量双方之间的直接影响。这种分布确实是一种产生'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征向量中心性Engenvector centrality&amp;lt;/font&amp;gt;'''的类型。它用于对 Hu (2020)中的大数据对象进行排序，比如美国大学排名。&lt;br /&gt;
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== 重要限制Important limitations ==&lt;br /&gt;
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Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the [[Krackhardt kite graph]], for which three different notions of centrality give three different choices of the most central vertex.&amp;lt;ref&amp;gt;{{cite journal|title=Assessing the Political Landscape: Structure, Cognition, and Power in Organizations|first=David|last=Krackhardt|authorlink=David Krackhardt|journal=Administrative Science Quarterly|volume=35|issue=2|date=June 1990|pages=342–369|doi=10.2307/2393394|jstor=2393394}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the Krackhardt kite graph, for which three different notions of centrality give three different choices of the most central vertex.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中心性Centrality&amp;lt;/font&amp;gt;'''指标有两个重要的局限性，一个显而易见，另一个则不易察觉。显而易见的局限性是，对于一个应用最优的中心性对于另一个应用常常是次优的。事实上，如果不是这样，我们就不需要这么多不同的中心性。克拉克哈特风筝图为这一现象提供了一个例证，对于这个图，三个不同的中心性概念给出了三个最中心顶点的不同选择。&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices.&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=Borgatti2005/&amp;gt; This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  [[node influence metric]]s to address this problem.&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices. This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  node influence metrics to address this problem.&lt;br /&gt;
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更不易察觉的限制是通常会错误地认为顶点中心性表示顶点的相对重要性。中心性指数被明确地设计来产生一个指出最重要顶点的排名。在刚才提到的限制下，他们做得很好。它们通常不用来测量节点的影响力。最近，网络物理学家开始开发'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;节点影响度量Node influence metrics &amp;lt;/font&amp;gt;'''来解决这个问题。&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying [[Centrality#Freeman centralization|Freeman centralization]] to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt; This approach, however, is seldom seen in practice.{{citation needed|reason=I've come across quite some theoretical studies that indicate otherwise. My suggestion is to remove this sentence, if reasonable citation is not provided.|date=September 2015}}&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying Freeman centralization to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores. This approach, however, is seldom seen in practice.&lt;br /&gt;
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错误有两方面。首先，一个排名只根据顶点的重要性排序，它并不对节点重要性的不同水平进行量化区分。这可以通过将 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;'''应用到中心性度量来缓解，这种度量可以根据节点的不同中心性得分来判断节点的重要性。此外， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;''使人们能够通过比较几个网络的最高中心性得分来比较它们。然而，这种方法在实践中很少见到。&lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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其次，用以(正确地)识别给定网络/应用中最重要顶点的特征并不一定可推广到其余顶点。&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot; /&amp;gt;&amp;lt;ref name=&amp;quot;daSilva2012&amp;quot;&amp;gt;{{cite journal | last1=da Silva|first1=Renato |last2=Viana|first2=Matheus|last3=da F. Costa |first3=Luciano| title=Predicting epidemic outbreak from individual features of the spreaders| journal=J. Stat. Mech.: Theory Exp. | year=2012|volume=2012|pages=P07005|number=7 | doi=10.1088/1742-5468/2012/07/p07005|arxiv=1202.0024|bibcode=2012JSMTE..07..005A}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Bauer2012&amp;quot;&amp;gt;{{cite journal | last1=Bauer|first1=Frank | last2=Lizier|first2=Joseph|title=Identifying influential spreaders and efficiently estimating infection numbers in epidemic models: A walk counting approach| journal=Europhys Lett | year=2012| volume=99| pages=68007|number=6 | doi=10.1209/0295-5075/99/68007|arxiv=1203.0502|bibcode=2012EL.....9968007B}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Sikic2013&amp;quot;&amp;gt;{{ cite journal| last1= Sikic| first1=Mile|last2=Lancic|first2=Alen|last3=Antulov-Fantulin|first3=Nino|last4=Stefanic|first4=Hrvoje| title = Epidemic centrality -- is there an underestimated epidemic impact of network peripheral nodes? |journal = The European Physical Journal B |volume=86 |number=10 |pages=1–13 |year=2013 | doi=10.1140/epjb/e2013-31025-5|arxiv=1110.2558 | bibcode=2013EPJB...86..440S}}&amp;lt;/ref&amp;gt; This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&amp;lt;ref name=&amp;quot;Ghoshal2011&amp;quot;&amp;gt;{{cite journal | last1=Ghoshal | first1= G. | last2= Barabsi |first2= A L | title = Ranking stability and super-stable nodes in complex networks. | journal = Nat Commun | volume =2 | page = 394| year= 2011 | doi=10.1038/ncomms1396 | pmid= 21772265 | bibcode=2011NatCo...2..394G | doi-access= free }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless. This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&lt;br /&gt;
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对于大多数其他网络节点，排名可能是没有意义的。这就解释了为什么，例如，只有谷歌图片搜索的前几个结果以合理的顺序出现。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页排名Pagerank&amp;lt;/font&amp;gt;'''是一个非常不稳定的度量，显示了在跳转参数小的调整之后频繁的秩逆转。&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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虽然中心性指数未能推广到网络的其他部分，乍看起来似乎是违反直觉的，但它直接遵循上述定义。&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot;&amp;gt;{{cite journal |last1= Lawyer |first1= Glenn |year= 2015 |title= Understanding the spreading power of all nodes in a network: a continuous-time perspective |journal=Sci Rep |volume=5|pages=8665|doi=10.1038/srep08665 |pmid=25727453 |pmc=4345333|arxiv=1405.6707|bibcode=2015NatSR...5E8665L}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&lt;br /&gt;
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复杂网络具有异构的拓扑结构。由于最佳度量取决于最重要顶点的网络结构，对于这些顶点最优的度量对于网络的其余部分是次优的。&lt;br /&gt;
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==Degree centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Degree (graph theory)}} &lt;br /&gt;
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[[File:6 centrality measures.png|thumb|right|300px|Examples of A) [[Betweenness centrality]], B) [[Closeness centrality]], C) [[Eigenvector centrality]], D) [[Degree centrality]], E) [[Centrality#Harmonic centrality|Harmonic centrality]] and F) [[Katz centrality]] of the same graph.]]&lt;br /&gt;
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Examples of A) [[Betweenness centrality, B) Closeness centrality, C) Eigenvector centrality, D) Degree centrality, E) Harmonic centrality and F) Katz centrality of the same graph.]]&lt;br /&gt;
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实例 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; a)[中介中心性A) [[Betweenness centrality,b)紧密中心性，B) Closeness centrality, c)特征向量中心性，C) Eigenvector centrality, d)度中心性，D) Degree centrality, e)调和中心性，E) Harmonic centrality andf) 卡兹Katz 中心性]F) Katz centrality .]]&amp;lt;/font&amp;gt;'''&lt;br /&gt;
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Historically first and conceptually simplest is '''degree centrality''', which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely [[indegree]] and [[outdegree]]. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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Historically first and conceptually simplest is degree centrality, which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely indegree and outdegree. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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历史上最简单的概念是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''，它定义为一个节点上发生的链接数量(即一个节点拥有的关系数量)。度可以根据节点捕获流经网络的任何东西(例如病毒或某些信息)的直接风险来解释。在有向网络的情况下(其中联系有方向) ，我们通常定义两个独立的度量，即 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度 Outdegree&amp;lt;/font&amp;gt;'''。因此，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度indegree&amp;lt;/font&amp;gt;'''是指向该节点的关系数，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度outdegree&amp;lt;/font&amp;gt;'''是指该节点指向其他节点的关系数。当关系与一些积极的方面如友谊或合作有关时， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''通常被解释为一种形式的受欢迎，而 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度Indegree&amp;lt;/font&amp;gt;'''则被解释为合群。&lt;br /&gt;
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The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
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The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
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对于给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边，度的中心性定义为&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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Calculating degree centrality for all the nodes in a graph takes [[big theta|&amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt;]] in a [[dense matrix|dense]] [[adjacency matrix]] representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a [[sparse matrix]] representation.&lt;br /&gt;
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Calculating degree centrality for all the nodes in a graph takes &amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt; in a dense adjacency matrix representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a sparse matrix representation.&lt;br /&gt;
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计算一个图中所有节点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''需要在图的稠密'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵Adjacency matrix &amp;lt;/font&amp;gt;'''表示中使用 Theta (v ^ 2) &amp;lt;/math &amp;gt; ，而在稀疏矩阵表示中使用 Theta (e) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of ''graph centralization''.&amp;lt;ref&amp;gt;Freeman, Linton C. &amp;quot;Centrality in social networks conceptual clarification.&amp;quot; Social networks 1.3 (1979): 215–239.&amp;lt;/ref&amp;gt; Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
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The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of graph centralization. Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
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节点级中心性的定义可以扩展到整个图，在这种情况下，我们指的是图的集中性。设 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 为 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''最高的节点。让 &amp;lt; math &amp;gt; x: = (y，z) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; | y | &amp;lt;/math &amp;gt; 节点连接图，最大化下列数量(&amp;lt; math &amp;gt; y * &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 中度最高的节点) :&lt;br /&gt;
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:&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; h = sum ^ { | y | }{ j = 1}[ c _ d (y *)-c _ d (y _ j)] &amp;lt;/math &amp;gt; &lt;br /&gt;
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Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
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Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
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相应地，图形 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''如下:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ h } &amp;lt;/math &amp;gt; &lt;br /&gt;
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The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a [[star graph]]), and in this case&lt;br /&gt;
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The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a star graph), and in this case&lt;br /&gt;
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当图形 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 包含一个所有其他节点都连接的中心节点(一个星形图)时，&amp;lt; math &amp;gt; h &amp;lt;/math &amp;gt; 的值最大化，在这种情况下&lt;br /&gt;
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:&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
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(n-1)-1) = n ^ 2-3n + 2&lt;br /&gt;
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So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
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So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
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所以，对于任意的图 &amp;lt; math &amp;gt; g: = (v，e) ，&amp;lt;/math &amp;gt; &lt;br /&gt;
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:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ | v | ^ 2-3 | v | + 2} &amp;lt;/math &amp;gt;&lt;br /&gt;
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==Closeness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Closeness centrality}}In a [[Connected component (graph theory)|connected]] [[Graph (discrete mathematics)|graph]], the [[Normalization (statistics)|normalized]] '''closeness centrality''' (or '''closeness''') of a node is the average length of the [[Shortest path problem|shortest path]] between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
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In a connected graph, the normalized closeness centrality (or closeness) of a node is the average length of the shortest path between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
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在连通图中，节点的标准'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''(或贴近性)是节点与图中所有其他节点之间最短路径的平均长度。因此，一个节点越是中心，它就越接近所有其他节点。&lt;br /&gt;
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Closeness was defined by [[Alex Bavelas]] (1950) as the [[Multiplicative inverse|reciprocal]] of the '''farness''',&amp;lt;ref&amp;gt;Alex Bavelas. Communication patterns in task-oriented groups. ''J. Acoust. Soc. Am'', '''22'''(6):725–730, 1950.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;{{cite journal|year=1966|title=The centrality index of a graph|url=|journal=Psychometrika|volume=31|issue=4|pages=581–603|doi=10.1007/bf02289527|pmid=5232444|hdl=10338.dmlcz/101401|last1=Sabidussi|first1=G|hdl-access=free}}&amp;lt;/ref&amp;gt; that is:&lt;br /&gt;
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Closeness was defined by Alex Bavelas (1950) as the reciprocal of the farness, that is:&lt;br /&gt;
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亚历克斯 · 巴维拉斯(1950)将亲密度定义为相对于距离的倒数，即:&lt;br /&gt;
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: &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
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 &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
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C (x) = frac {1}{ sum _ y d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the [[Distance (graph theory)|distance]] between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
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where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the distance between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; d (y，x) &amp;lt;/math &amp;gt; 是顶点 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; 之间的距离。然而，当谈到'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''时，人们通常会提到它的标准化形式，一般是以前的公式乘以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; ，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。这种调整允许比较不同大小图形的节点。&lt;br /&gt;
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Taking distances ''from'' or ''to'' all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in [[directed graph]]s (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
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Taking distances from or to all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in directed graphs (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
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从所有其他节点或到所有其他节点的距离在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 无向图Undirected graphs&amp;lt;/font&amp;gt;'''中是不相关的，但是在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 有向图Directed graphs&amp;lt;/font&amp;gt;'''中可能产生完全不同的结果(例如:一个网站可以从传出链接获得高的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，而从传入链接获得低的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''）。&lt;br /&gt;
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===Harmonic centrality===&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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In a (not necessarily connected) graph, the '''harmonic centrality''' reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
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In a (not necessarily connected) graph, the harmonic centrality reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
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在一个(不一定是连通的)图中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''反转了'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''定义中的和互反运算:&lt;br /&gt;
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: &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
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 &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; h (x) = sum { y neq x } frac {1}{ d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
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where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
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where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; 1/d (y，x) = 0 &amp;lt;/math &amp;gt; if there is no path from &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; to &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 。调和中心性可以通过除以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; 来标准化，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。&lt;br /&gt;
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Harmonic centrality was proposed by [[Massimo Marchiori|Marchiori]] and [[Vito Latora|Latora]] (2000)&amp;lt;ref name=&amp;quot;marchiorilatora2000&amp;quot;&amp;gt;{{citation| journal = Physica A: Statistical Mechanics and Its Applications  | last1 = Marchiori | first1 = Massimo | last2 = Latora | first2 = Vito | year = 2000 | volume = 285 | issue = 3–4 | pages = 539–546 | title = Harmony in the small-world | doi=10.1016/s0378-4371(00)00311-3| arxiv = cond-mat/0008357 | bibcode = 2000PhyA..285..539M }}&amp;lt;/ref&amp;gt; and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot;&amp;lt;ref&amp;gt;{{cite journal|first1=Anthony|last1=Dekker|title=Conceptual Distance in Social Network Analysis|journal=Journal of Social Structure|volume=6|issue=3|year=2005|url=http://www.cmu.edu/joss/content/articles/volume6/dekker/index.html}}&amp;lt;/ref&amp;gt; and by Rochat (2009).&amp;lt;ref&amp;gt;{{cite conference  | author = Yannick Rochat  | title = Closeness centrality extended to unconnected graphs: The harmonic centrality index | conference = Applications of Social Network Analysis, ASNA 2009 | url = http://infoscience.epfl.ch/record/200525/files/%5bEN%5dASNA09.pdf }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Harmonic centrality was proposed by Marchiori and Latora (2000) and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot; and by Rochat (2009).&lt;br /&gt;
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调和中心性是由 Marchiori 和 Latora (2000)提出的，然后是 Dekker (2005)独立提出的，使用的名称是“有价值的中心性” ，Rochat (2009)。&lt;br /&gt;
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==Betweenness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Betweenness centrality}}&lt;br /&gt;
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[[File:Graph betweenness.svg|240px|right|thumb|Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.]]&lt;br /&gt;
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Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.&lt;br /&gt;
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色调(从红色 = 0到蓝色 = max)表示节点之间的距离。&lt;br /&gt;
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'''Betweenness''' is a centrality measure of a [[vertex (graph theory)|vertex]] within a [[Graph (discrete mathematics)|graph]] (there is also [[edge (graph theory)|edge]] betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by [[Linton Freeman]]&amp;lt;ref name=&amp;quot;freeman1977&amp;quot;&amp;gt;{{cite journal |last1 = Freeman |first1 = Linton | year=1977| title = A set of measures of centrality based upon betweenness | journal = Sociometry| volume=40|issue = 1 | pages=35–41 | doi=10.2307/3033543|jstor = 3033543 }}&amp;lt;/ref&amp;gt; In his conception, vertices that have a high probability to occur on a randomly chosen [[shortest path problem|shortest path]] between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
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Betweenness is a centrality measure of a vertex within a graph (there is also edge betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by Linton Freeman In his conception, vertices that have a high probability to occur on a randomly chosen shortest path between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
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中介性是图中顶点的中心性度量(也有边中介性，这里没有讨论)。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''量化了一个节点沿着其他两个节点之间的最短路径充当桥梁的次数。在林顿 · 弗里曼的概念中，在两个随机选择的顶点之间随机选择的最短路径上出现概率高的顶点具有很高的中介性。&lt;br /&gt;
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The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
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The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
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在一个图 &amp;lt; math &amp;gt; g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的顶点之间的距离计算如下:&lt;br /&gt;
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# For each pair of vertices (''s'',''t''), compute the [[Shortest path problem|shortest paths]] between them.&lt;br /&gt;
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 For each pair of vertices (s,t), compute the shortest paths between them.&lt;br /&gt;
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对于每一对顶点(s，t) ，计算它们之间的最短路径。&lt;br /&gt;
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# For each pair of vertices (''s'',''t''), determine the fraction of shortest paths that pass through the vertex in question (here, vertex ''v'').&lt;br /&gt;
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 For each pair of vertices (s,t), determine the fraction of shortest paths that pass through the vertex in question (here, vertex v).&lt;br /&gt;
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对于每对顶点(s，t) ，确定通过该顶点(这里是顶点 v)的最短路径的分数。&lt;br /&gt;
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# Sum this fraction over all pairs of vertices (''s'',''t'').&lt;br /&gt;
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 Sum this fraction over all pairs of vertices (s,t).&lt;br /&gt;
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对所有顶点对(s，t)求这个分数的和。&lt;br /&gt;
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More compactly the betweenness can be represented as:&amp;lt;ref name=&amp;quot;brandes&amp;quot;&amp;gt;{{cite journal |last1 = Brandes |first1 = Ulrik | year=2001 |title = A faster algorithm for betweenness centrality  | journal = Journal of Mathematical Sociology| volume=25|issue = 2 | pages=163–177| url = http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.11.2024 | accessdate = October 11, 2011| format = PDF | doi=10.1080/0022250x.2001.9990249|citeseerx = 10.1.1.11.2024 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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More compactly the betweenness can be represented as:&lt;br /&gt;
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更确切地说，两者之间的关系可以表示为:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
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{ math &amp;gt; c _ b (v) = sum _ { s neq v neq t in v } frac { sigma _ st }(v)}{ sigma _ st } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including ''v'', which for [[Digraph (mathematics)|directed graphs]] is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected [[Star (graph theory)|star graph]], the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including v, which for directed graphs is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected star graph, the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; sigma { st } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { st }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径数。有向图是 &amp;lt; math &amp;gt; (n-1)(n-2) &amp;lt;/math &amp;gt; ，无向图是 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; 。例如，在一个无向星图中，中心顶点(包含在每个可能的最短路径中)的中介性为 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; (1，如果标准化) ，而叶子(包含在没有最短路径中)的中介性为0。&lt;br /&gt;
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From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires [[Big O notation|&amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt;]] time with the [[Floyd–Warshall algorithm]]. However, on sparse graphs, [[Johnson's algorithm]] may be more efficient, taking [[Big O notation|&amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt;]] time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm&amp;lt;ref name=brandes/&amp;gt; which takes [[Big O notation|&amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt;]] time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&amp;lt;ref name=&amp;quot;brandes&amp;quot; /&amp;gt;&lt;br /&gt;
&lt;br /&gt;
From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires &amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt; time with the Floyd–Warshall algorithm. However, on sparse graphs, Johnson's algorithm may be more efficient, taking &amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt; time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm which takes &amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt; time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&lt;br /&gt;
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从计算的角度来看，图中所有顶点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介和紧密中心性Betweenness and Closeness centralities&amp;lt;/font&amp;gt;'''都涉及到计算图中所有顶点对之间的最短路径，这就需要用 Floyd-Warshall 算法计算时间。然而，对于稀疏图，约翰逊算法的效率可能更高，采用 &amp;lt; math &amp;gt; o (v ^ 2 log v + v e) &amp;lt;/math &amp;gt; 时间。在不加权图的情况下，可以用 Brandes 的算法进行计算，该算法需要 &amp;lt; math &amp;gt; o (v e) &amp;lt;/math &amp;gt; 时间。一般情况下，这些算法假定图是无向的，并且连通图中允许有圈和多条边。当专门处理网络图时，图通常没有环或多条边来维持简单的关系(其中的边表示两个人或顶点之间的联系)。在这种情况下，使用 Brandes 的算法将最终的中心性分数除以2来计算每条被重复计算的最短路径。&lt;br /&gt;
&lt;br /&gt;
==Eigenvector centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Eigenvector centrality}}&lt;br /&gt;
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'''Eigenvector centrality''' (also called '''eigencentrality''') is a measure of the influence of a [[node (networking)|node]] in a [[network (mathematics)|network]]. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&amp;lt;ref&amp;gt;{{cite journal|title = The mathematics of networks|url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf|author = M. E. J. Newman|accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;/&amp;gt; [[Google]]'s [[PageRank]] and the [[Katz centrality]] are variants of the eigenvector centrality.&amp;lt;ref name=&amp;quot;ams&amp;quot;&amp;gt;{{Cite web | url=http://www.ams.org/samplings/feature-column/fcarc-pagerank | title=American Mathematical Society}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Eigenvector centrality (also called eigencentrality) is a measure of the influence of a node in a network. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''(也称为特征中心性)是衡量网络中节点影响的一个指标。它将相对得分分配给网络中的所有节点，这是基于这样一个概念: 与得分较高的节点相比，与得分较低的节点相同的连接对所涉及的节点的得分贡献更大。&lt;br /&gt;
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=== Using the adjacency matrix to find eigenvector centrality ==&lt;br /&gt;
==使用'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''发现'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the [[adjacency matrix]], i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
&lt;br /&gt;
For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the adjacency matrix, i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
&lt;br /&gt;
对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 让 &amp;lt; math &amp;gt; a = (a { v，t }) &amp;lt;/math &amp;gt; 成为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''，即。如果顶点 &amp;lt; math &amp;gt; &amp;gt; v &amp;lt;/math &amp;gt; 与 math &amp;gt; t &amp;lt;/math &amp;gt; 相连，而 &amp;lt; math &amp;gt; a { v，t } = 0 &amp;lt;/math &amp;gt; 否则。顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分可以定义为:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
在 m (v)} x _ t = frac {1}{ lambda } sum { t in g } a { v，t } x _ t &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the [[eigenvector]] equation&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the eigenvector equation&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; m (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 和 &amp;lt; math &amp;gt; &amp;gt; lambda &amp;lt;/math &amp;gt; 的邻居集合。通过一个小的重新排列，这可以被重写成向量符号，作为特征向量方程&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[ math &amp;gt; mathbf { Ax } = { lambda } mathbf { x } &amp;lt;/math &amp;gt; &lt;br /&gt;
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In general, there will be many different [[eigenvalue]]s &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the [[Perron–Frobenius theorem]]. This greatest eigenvalue results in the desired centrality measure.&amp;lt;ref&amp;gt;{{cite journal  | author = M. E. J. Newman  | title = The mathematics of networks  | url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf  | accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt; The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices ''n''. [[Power iteration]] is one of many [[eigenvalue algorithm]]s that may be used to find this dominant eigenvector.&amp;lt;ref name=&amp;quot;ams&amp;quot; /&amp;gt; Furthermore, this can be generalized so that the entries in ''A'' can be real numbers representing connection strengths, as in a [[stochastic matrix]].&lt;br /&gt;
&lt;br /&gt;
In general, there will be many different eigenvalues &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the Perron–Frobenius theorem. This greatest eigenvalue results in the desired centrality measure. The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices n. Power iteration is one of many eigenvalue algorithms that may be used to find this dominant eigenvector. Furthermore, this can be generalized so that the entries in A can be real numbers representing connection strengths, as in a stochastic matrix.&lt;br /&gt;
&lt;br /&gt;
一般情况下，存在许多不同的特征值，对于这些特征值存在一个非零特征向量解。由于邻接矩阵中的条目是非负的，所以由 Perron-弗罗贝尼乌斯定理得出，它有一个实的和正的唯一最大特征值。由这个最大的特征值得出期望的中心性度量。相关特征向量的 &amp;lt; math &amp;gt; v ^ { th } &amp;lt;/math &amp;gt; 分量给出了网络中顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分。特征向量只定义了一个公共因子，所以只有顶点中心的比例是明确定义的。要定义一个绝对分数，必须对特征向量进行标准化，例如，使所有顶点的和为1或顶点的总数n。此外，这可以通用，使得 a 中的条目可以是表示连接强度的真实数字，就像'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 随机矩阵Stochastic matrix&amp;lt;/font&amp;gt;'''中一样。&lt;br /&gt;
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==Katz centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Katz centrality}}&lt;br /&gt;
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'''Katz centrality'''&amp;lt;ref&amp;gt;Katz, L. 1953. A New Status Index Derived from Sociometric Index. Psychometrika, 39–43.&amp;lt;/ref&amp;gt; is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
Katz centrality is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''是度中心性的推广。度中心性度量的是直接邻居的数量，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''度量的是通过一条路径可以连接的所有节点的数量，而远处节点的贡献会受到'''&amp;lt;font color=&amp;quot;#32CD32&amp;quot;&amp;gt; '削弱（惩罚？）Penalized&amp;lt;/font&amp;gt;''。在数学上，它被定义为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[数学][数学]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; (0,1) &amp;lt;/math &amp;gt; 中的衰减因子。&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
&lt;br /&gt;
Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''可以看作是特征向量中心性的变体。Katz 中心性的另一种形式是&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
(x _ j + 1) &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
与特征向量中心性的表达式相比，&amp;lt; math &amp;gt; x _ j &amp;lt;/math &amp;gt; 被 &amp;lt; math &amp;gt; x _ j + 1所代替&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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It is shown that&amp;lt;ref&amp;gt;{{cite journal | last1 = Bonacich | first1 = P | year = 1991 | title = Simultaneous group and individual centralities | url = | journal = Social Networks | volume = 13 | issue = 2| pages = 155–168 | doi=10.1016/0378-8733(91)90018-o}}&amp;lt;/ref&amp;gt; the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
&lt;br /&gt;
It is shown that the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
&lt;br /&gt;
结果表明，主特征向量(与 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; ，邻接矩阵的最大特征值相关)是 Katz 中心性的极限，因为 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 接近 &amp;lt; math &amp;gt; tfrac {1}{ lambda } &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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== PageRank centrality ==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页分布中心性PageRank&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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{{main|PageRank}}'''[[PageRank]]''' satisfies the following equation&lt;br /&gt;
&lt;br /&gt;
PageRank satisfies the following equation&lt;br /&gt;
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PageRank满足下面的等式&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1-alpha { n } ，&amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
其中&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[ math &amp;gt; l (j) = sum { i } a { ji } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&amp;lt;ref&amp;gt;[http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf How does Google rank webpages?] {{webarchive | url= https://web.archive.org/web/20120131083328/http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf |date=January 31, 2012 }} 20Q: About Networked Life&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&lt;br /&gt;
&lt;br /&gt;
是节点 &amp;lt; math &amp;gt; j &amp;lt;/math &amp;gt; (或有向图中出站链接的数量)的邻居数量。与特征向量中心性和 Katz 中心性相比，尺度因子 &amp;lt; math &amp;gt; l (j) &amp;lt;/math &amp;gt; 是一个主要的区别。PageRank 和特征向量中心性的另一个区别是 PageRank 向量是一个左手特征向量(注意因子 &amp;lt; math &amp;gt; a _ { ji } &amp;lt;/math &amp;gt; 具有相反的索引)。&lt;br /&gt;
&lt;br /&gt;
==Percolation centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&amp;lt;ref name=&amp;quot;piraveenan2013&amp;quot;&amp;gt;{{cite journal |last1 = Piraveenan |first1 = M. |last2 = Prokopenko |first2 = M.|last3 = Hossain|first3 = L. |year=2013| title = Percolation Centrality: Quantifying Graph-Theoretic Impact of Nodes during Percolation in Networks | journal = PLOS One | volume=8 | issue=1 | doi=10.1371/journal.pone.0053095 | pages=e53095 | pmid=23349699 | pmc=3551907| bibcode=2013PLoSO...853095P }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&lt;br /&gt;
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在复杂网络中，存在大量的中心性度量来确定单个节点的“重要性”。然而，这些度量单纯从拓扑学的角度来量化节点的重要性，节点的值并不以任何方式依赖于节点的状态。不管网络动态如何，它都保持不变。即使对于加权的两者之间的度量也是如此。然而，一个节点可能很好地位于'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''或其他中心性度量的中心位置，但可能不是位于有过滤的网络的上下文中的中心位置。在许多情况下，复杂网络中都会出现“传染”现象。例如，病毒或细菌感染可以通过人们的社交网络传播，也就是所谓的接触网络。还可以在更高的抽象层次上考虑疾病的传播问题，设想通过公路、铁路或空中连接起来的城镇或人口中心网络。计算机病毒可以通过计算机网络传播。关于商业活动和交易的谣言或新闻也可以通过人们的社交网络传播。在所有这些情况下，一种“传染病”在一个复杂网络的链接上传播，随着它的传播，无论是可恢复的还是不可恢复的，都会改变节点的“状态”。例如，在流行病学方案中，随着感染扩散，个人从”易感”状态转变为”受感染”状态。在上面的例子中，随着传染的扩散，每个节点可以采取的状态可以是二进制的(例如接收/没有接收到一条新闻)、离散的(易感/受感染/康复) ，甚至是连续的(例如一个城镇中受感染的人的比例) 。这些情景的共同特点是，传染的扩散导致网络中节点状态的改变。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''（PC)就是基于这个思想而提出的，它特别地衡量了节点在协助网络渗滤方面的重要性。这项措施是由 piraveanan 等人提出的。&lt;br /&gt;
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'''Percolation centrality''' is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
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Percolation centrality is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''定义为在给定时间内一个给定节点的过滤路径的比例。“渗滤路径”是一对节点之间的最短路径，其中源节点被渗滤(例如，被感染)。目标节点可以是过滤的或非过滤的，或处于部分过滤状态。&lt;br /&gt;
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:&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; PC ^ t (v) = frac {1}{ N-2} sum { s neq v neq r } frac { sigma { sr }(v)}{ sigma { sr }} frac { x ^ t }{ sum {[{ x ^ t } i }}}]}}-{ x ^ t }{ v } &amp;lt;/math &amp;gt; &lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; σ { sr } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; r &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { sr }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径的总数。在时间 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 时，节点的过滤状态用 &amp;lt; math &amp;gt; { x ^ t } _ i &amp;lt;/math &amp;gt; 表示，两个特殊情况是当 &amp;lt; math &amp;gt; { x ^ t } _ i = 0 &amp;lt;/math &amp;gt; 表示在时间上是非过滤状态，而当 &amp;lt; math &amp;gt; &amp;lt; x ^ t &amp;lt;/math &amp;gt; i = 1 &amp;lt;/math &amp;gt; 表示在时间上是完全过滤状态。两者之间的值表示部分过滤状态(例如，在一个城镇网络中，这是该城镇感染者的百分比)。&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in [[Big O notation|&amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt;]] time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is [[Big O notation|&amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;]].&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in &amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt; time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is &amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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渗流路径的权重取决于分配给源节点的渗流水平，前提是源节点的渗流水平越高，源节点的路径就越重要。因此，位于源自高渗滤节点的最短路径上的节点可能对渗滤更为重要。PC 的定义也可以扩展到包括目标节点的权重。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''计算运行在 &amp;lt; math &amp;gt; o (NM) &amp;lt;/math &amp;gt; 时间，采用了 Brandes 快速算法的有效实现，如果计算需要考虑目标节点的权重，最坏情况下时间为 &amp;lt; math &amp;gt; o (n ^ 3) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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==Cross-clique centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 交叉团中心性Cross-clique centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
'''Cross-clique centrality''' of a single node in a complex graph determines the connectivity of a node to different [[clique (graph theory)|clique]]s. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in &amp;lt;ref name=&amp;quot;xssworms&amp;quot;&amp;gt;{{cite journal |last1 = Faghani|first1 = Mohamamd Reza| year=2013| title = A Study of XSS Worm Propagation and Detection Mechanisms in Online Social Networks | journal = IEEE Transactions on Information Forensics and Security|volume = 8|issue = 11|pages = 1815–1826|doi = 10.1109/TIFS.2013.2280884}}&amp;lt;/ref&amp;gt; but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
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Cross-clique centrality of a single node in a complex graph determines the connectivity of a node to different cliques. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in  but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
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复杂图中单个节点的跨团中心性决定了一个节点与不同团的连通性。具有高度跨团连通性的节点有利于信息或疾病在图中的传播。团是一种'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图Subgraphs&amp;lt;/font&amp;gt;'''，团中的每个节点都与团中的其他节点相连。对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边的交叉团连通性，定义为 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; x (v) &amp;lt;/math &amp;gt; 其中 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 所属的顶点团数。这个测度应用日久，但是在1998年由 Everett 和 Borgatti 首次提出，他们称之为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 派系重叠中心性Clique-overlap centrality&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Freeman centralization==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心度Freeman centralization&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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The '''centralization''' of any network is a measure of how central its most central node is in relation to how central all the other nodes are.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;&amp;gt;{{citation | journal = Social Networks | last1 = Freeman | first1 = Linton C. | year = 1979 | volume = 1 | issue = 3 | pages = 215–239 | title = centrality in social networks: Conceptual clarification | url = http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | doi = 10.1016/0378-8733(78)90021-7 | citeseerx = 10.1.1.227.9549 | access-date = 2014-07-31 | archive-url = https://web.archive.org/web/20160222033108/http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | archive-date = 2016-02-22 | url-status = dead }}&amp;lt;/ref&amp;gt; Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
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The centralization of any network is a measure of how central its most central node is in relation to how central all the other nodes are. Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
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任何网络的集中度都是衡量其最核心的节点相对于其他所有节点的集聚程度的标准。集中度的度量方法是: (a)计算网络中最中心的节点与所有其他节点之间的中心性差异之和; (b)将这个数量除以理论上相同规模的任何网络中这种差异之和的最大值。因此，每个中心性度量都可以有自己的集中性度量。正式定义，如果 &amp;lt; math &amp;gt; c _ x (p _ i) &amp;lt;/math &amp;gt; 是点 &amp;lt; math &amp;gt; i &amp;lt;/math &amp;gt; 的中心性度量，如果 &amp;lt; math &amp;gt; c _ x (p _ *) &amp;lt;/math &amp;gt; 是网络中最大的中心性度量，如果:&lt;br /&gt;
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:&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; max sum { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i) &amp;lt;/math &amp;gt; &lt;br /&gt;
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is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;&lt;br /&gt;
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is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&lt;br /&gt;
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对于任何具有相同节点数的图来说，点中心性的最大差异是:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; c _ x = frac { sum _ { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i)}{ max sum _ { i = 1 ^ { n } c _ x (p _ *)-c _ x (p _ i)} . &amp;lt;/math &amp;gt;&lt;br /&gt;
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== Dissimilarity based centrality measures ==&lt;br /&gt;
==基于相异性的中心性度量==&lt;br /&gt;
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[[File:Srep17095-f1.jpg|thumbnail|In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.]]&lt;br /&gt;
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In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.&lt;br /&gt;
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在图示的网络中，绿色节点和红色节点最不相似，因为它们之间不共享相邻节点。因此，绿色的节点比灰色的节点对中心性的贡献更大，因为红色的节点只能通过绿色访问蓝色的节点，而灰色的节点对于红色的节点是多余的，因为它可以直接访问每个灰色的节点，而不需要任何中介。&lt;br /&gt;
&lt;br /&gt;
In order to obtain better results in the ranking of the nodes of a given network,  in &amp;lt;ref&amp;gt;{{Cite journal|title = Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|journal = Scientific Reports|date = 2015-11-25|pmc = 4658528|pmid = 26603652|volume = 5|doi = 10.1038/srep17095|first = A. J.|last = Alvarez-Socorro|first2 = G. C.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz|pages=17095|bibcode = 2015NatSR...517095A}}&amp;lt;/ref&amp;gt; are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with [[eigenvector centrality]], calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
&lt;br /&gt;
In order to obtain better results in the ranking of the nodes of a given network,  in  are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with eigenvector centrality, calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
&lt;br /&gt;
为了在给定网络节点的排序中获得更好的结果，在复杂网络中使用了相异性度量(特定于分类和数据挖掘理论)来丰富中心性度量。特征向量中心性通过求解特征值问题来计算每个节点的中心性&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
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数学，数学&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary [[Matrix similarity|dissimilarity]] matrix, defined through a dissimilitary measure, e.g., [[Jaccard index|Jaccard]] dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary dissimilarity matrix, defined through a dissimilitary measure, e.g., Jaccard dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
这里 &amp;lt; math &amp;gt; w { ij } = a { ij } d { ij } &amp;lt;/math &amp;gt; (coordinate-to-coordinate product)和 &amp;lt; math &amp;gt; d { ij } &amp;lt;/math &amp;gt; 是一个任意的不相似矩阵，通过一个双重军事度量来定义，例如，Jaccard 由&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1-dfrac { | v ^ { + }(i) cap v ^ { + }(j) | }{ | v ^ { + }(i) cup v ^ { + }(j) | } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
&lt;br /&gt;
Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
&lt;br /&gt;
这种度量允许我们量化每个节点对给定节点中心性的拓扑贡献(这就是为什么我们称之为贡献中心性) ，对那些相异性较大的节点有更多的权重/相关性，因为这些节点允许给定的节点访问那些它们自己不能直接访问的节点。&lt;br /&gt;
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&lt;br /&gt;
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Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the [[Perron–Frobenius theorem]] to ensure that the above problem has a unique solution for ''λ'' = ''λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt;'' with '''c''' non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
&lt;br /&gt;
Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the Perron–Frobenius theorem to ensure that the above problem has a unique solution for λ = λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt; with c non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
&lt;br /&gt;
值得注意的是，&amp;lt; math &amp;gt; w &amp;lt;/math &amp;gt; 是非负的，因为 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; d &amp;lt;/math &amp;gt; 都是非负矩阵，所以我们可以使用 Perron 弗罗贝尼乌斯定理来确保上述问题对于 c 非负的 = &amp;lt; sub &amp;gt; max &amp;lt;/sub &amp;gt; 有唯一的解，这样我们就可以推断出网络中每个节点的中心性。因此，i-th 节点的中心性为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1{ n } sum { j = 1} ^ { n } w { ij } c { j } ，，，，，j = 1，cdots，n &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in &amp;lt;ref&amp;gt;{{Cite web|url = http://www.nature.com/article-assets/npg/srep/2015/151125/srep17095/extref/srep17095-s1.pdf|title = Supplementary Information for Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|date = |website = |publisher = Nature Publishing Group|last = Alvarez-Socorro|first = A.J.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz}}&amp;lt;/ref&amp;gt; obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in  obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是网络中的节点数。几个不同的措施和网络进行了测试，以获得在研究案例的改善的结果。&lt;br /&gt;
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==Extensions==&lt;br /&gt;
==扩展==&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality&amp;lt;ref&amp;gt;{{cite journal | last1 = Braha | first1 = D. | last2 = Bar-Yam | first2 = Y. | year = 2006 | title = From Centrality to Temporary Fame: Dynamic Centrality in Complex Networks | url = | journal = Complexity | volume = 12 | issue = 2| pages = 59–63 | doi=10.1002/cplx.20156| arxiv = physics/0611295 | bibcode = 2006Cmplx..12b..59B }}&amp;lt;/ref&amp;gt; in the context of time-dependent and temporal networks.&amp;lt;ref&amp;gt;{{cite journal | last1 = Hill | first1 = S.A. | last2 = Braha | first2 = D. | year = 2010 | title = Dynamic Model of Time-Dependent Complex Networks | url = | journal = Physical Review E | volume = 82 | issue = 4| page = 046105 | doi=10.1103/physreve.82.046105| pmid = 21230343 | arxiv = 0901.4407 | bibcode = 2010PhRvE..82d6105H }}&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Gross, T. and Sayama, H. (Eds.). 2009. ''Adaptive Networks: Theory, Models and Applications.'' Springer.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Holme, P. and Saramäki, J. 2013. ''Temporal Networks.'' Springer.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality in the context of time-dependent and temporal networks.&lt;br /&gt;
&lt;br /&gt;
经验和理论研究已经将静态网络中的中心性概念扩展到时间依赖网络和时间网络中的动态中心性。&lt;br /&gt;
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For generalizations to weighted networks, see Opsahl et al. (2010).&amp;lt;ref&amp;gt;{{cite journal | last1 = Opsahl | first1 = Tore | last2 = Agneessens | first2 = Filip | last3 = Skvoretz | first3 = John | title = Node centrality in weighted networks: Generalizing degree and shortest paths | doi = 10.1016/j.socnet.2010.03.006 | year = 2010 | pages = 245–251 | volume = 32 | journal = Social Networks | url = http://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | issue = 3 | access-date = 2010-04-23 | archive-url = https://web.archive.org/web/20180226080331/https://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | archive-date = 2018-02-26 | url-status = dead }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&lt;br /&gt;
&lt;br /&gt;
对加权网络的推广，见 Opsahl 等人。(2010).&lt;br /&gt;
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The concept of centrality was extended to a group level as well. For example, '''group betweenness''' centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&amp;lt;ref name=&amp;quot;group1&amp;quot;&amp;gt;Everett, M. G. and Borgatti, S. P. (2005). Extending centrality. In P. J. Carrington, J. Scott and S. Wasserman (Eds.), ''Models and methods in social network analysis'' (pp. 57–76). New York: Cambridge University Press.&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;group2&amp;quot;&amp;gt;Puzis, R., Yagil, D., Elovici, Y., Braha, D. (2009).[http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf Collaborative attack on Internet users’ anonymity] {{Webarchive|url=https://web.archive.org/web/20131207133417/http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf |date=2013-12-07 }}, ''Internet Research'' '''19'''(1)&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, group betweenness centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&lt;br /&gt;
&lt;br /&gt;
中心性的概念也扩展到了群体层次。例如，组间的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''显示了连接穿过组的成对非组成员的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Geodesics &amp;lt;/font&amp;gt;'''的比例。&lt;br /&gt;
&lt;br /&gt;
==See also==&lt;br /&gt;
==又及==&lt;br /&gt;
* [[Alpha centrality]]&lt;br /&gt;
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* [[Core–periphery structure]]&lt;br /&gt;
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* [[Distance (graph theory)|Distance in graphs]]&lt;br /&gt;
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*阿尔法中心性&lt;br /&gt;
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*核心—外围结构&lt;br /&gt;
&lt;br /&gt;
*距离（图理论）图中的距离&lt;br /&gt;
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==Notes and references==&lt;br /&gt;
&lt;br /&gt;
{{Reflist}}&lt;br /&gt;
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==Further reading==&lt;br /&gt;
拓展阅读&lt;br /&gt;
* Koschützki, D.; Lehmann, K. A.; Peeters, L.; Richter, S.; Tenfelde-Podehl, D. and Zlotowski, O. (2005) Centrality Indices. In Brandes, U. and Erlebach, T. (Eds.)  ''Network Analysis: Methodological Foundations'', pp.&amp;amp;nbsp;16–61, LNCS 3418, Springer-Verlag.&lt;br /&gt;
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[[Category:Graph theory]]&lt;br /&gt;
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Category:Graph theory&lt;br /&gt;
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分类: 图论&lt;br /&gt;
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[[Category:Graph algorithms]]&lt;br /&gt;
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Category:Graph algorithms&lt;br /&gt;
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分类: 图形算法&lt;br /&gt;
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[[Category:Algebraic graph theory]]&lt;br /&gt;
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Category:Algebraic graph theory&lt;br /&gt;
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分类: 代数图论&lt;br /&gt;
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[[Category:Networks]]&lt;br /&gt;
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Category:Networks&lt;br /&gt;
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分类: 网络&lt;br /&gt;
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[[Category:Network analysis]]&lt;br /&gt;
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Category:Network analysis&lt;br /&gt;
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分类: 网络分析&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Centrality]]. Its edit history can be viewed at [[网络中心性/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
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		<title>网络中心性</title>
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		<updated>2020-12-10T07:26:45Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：&lt;/p&gt;
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&lt;div&gt;此词条暂由水流心不竞初译，未经审校，带来阅读不便，请见谅。&lt;br /&gt;
&lt;br /&gt;
{{for|the statistical concept|Central tendency}}&lt;br /&gt;
{{Network Science}}&lt;br /&gt;
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In [[graph theory]] and [[network theory|network analysis]], indicators of '''centrality''' identify the most important [[vertex (graph theory)|vertices]] within a graph. Applications include identifying the most influential person(s) in a [[social network]], key infrastructure nodes in the [[Internet]] or [[urban network]]s, and [[super-spreader]]s of disease. Centrality concepts were first developed in [[social network analysis]], and many of the terms used to measure centrality reflect their [[sociology|sociological]] origin.&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
In graph theory and network analysis, indicators of centrality identify the most important vertices within a graph. Applications include identifying the most influential person(s) in a social network, key infrastructure nodes in the Internet or urban networks, and super-spreaders of disease. Centrality concepts were first developed in , and many of the terms used to measure centrality reflect their sociological origin.&lt;br /&gt;
&lt;br /&gt;
They should not be confused with [[node influence metric]]s, which seek to quantify the influence of every node in the network.&lt;br /&gt;
&lt;br /&gt;
They should not be confused with node influence metrics, which seek to quantify the influence of every node in the network.&lt;br /&gt;
&lt;br /&gt;
在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;图论 graph theory &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络分析 network analysis &amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性 centrality &amp;lt;/font&amp;gt;'''指标用于识别图中最重要的顶点。其应用包括在社会网络中识别出最有影响力的个人，在因特网或城市网络中识别出最为关键的基础设施节点，以及识别疾病的超级传播者。中心性的概念最初由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;社会网络分析 social network analysis&amp;lt;/font&amp;gt;'''所发展，因此许多用于衡量中心性的术语都反映出了它们的社会学出身。&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;中心性不应与节点影响度相混淆，后者意在量化网络中每个节点的影响。&lt;br /&gt;
&lt;br /&gt;
==中心性指数的定义与特性Definition and characterization of centrality indices==&lt;br /&gt;
&lt;br /&gt;
Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性指数 centrality indices&amp;lt;/font&amp;gt;'''旨在探寻如何描绘重要节点这一问题。这一问题的答案通常实值函数的形式给出，可根据函数值将图中各节点进行排序，进而确定最为重要的节点。&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
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The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
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“重要性”的含义十分广泛，因此导致了许多不同的中心性定义方式，我们可以将各种不同的定义方式划分为如下两类。&lt;br /&gt;
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&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important.&amp;lt;ref name=Borgatti2005/&amp;gt; &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt; Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important. &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&lt;br /&gt;
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“重要性”可以被设想为与网络中的某种流动或传输有关。&amp;lt;ref name=Borgatti2005/&amp;gt; “重要性”也可以被设想为与网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;内聚力 cohesiveness&amp;lt;/font&amp;gt;'''有关。这允许我们根据内聚力的不同测量方式对中心性予以分类。&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;这些方法将中心性划分于完全不同的类别中，也就是在一种类别中的中心性往往无法适用于其他类别。&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one ([[Centrality#Degree centrality|degree centrality]]) to infinite walks ([[Centrality#Eigenvector centrality|eigenvalue centrality]]).&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=&amp;quot;Benzi2013&amp;quot;&amp;gt;{{cite journal | last1=Benzi | first1=Michele | last2=Klymko| first2=Christine | year=2013 |title= A matrix analysis of different centrality measures |arxiv=1312.6722 | doi=10.1137/130950550 | volume=36 | issue=2 | journal=SIAM Journal on Matrix Analysis and Applications | pages=686–706}}&amp;lt;/ref&amp;gt; The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one (degree centrality) to infinite walks (eigenvalue centrality). The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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当根据内聚力方法对中心性进行分类时，很明显大多数中心性都将被划分于同一类别。起始于给定顶点的步数总和仅取决于步数的定义以及计数方式。这种分类方式的不足表现为它仅能较弱的描绘中心性特征，即按照一步步度（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;度中心性 degree centrality&amp;lt;/font&amp;gt;'''）到无穷步步长（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 eigenvalue centrality&amp;lt;/font&amp;gt;'''）的方式将中心性置于一种光谱状的分类中。&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=&amp;quot;Benzi2013&amp;quot;&amp;gt;{{cite journal | last1=Benzi | first1=Michele | last2=Klymko| first2=Christine | year=2013 |title= A matrix analysis of different centrality measures |arxiv=1312.6722 | doi=10.1137/130950550 | volume=36 | issue=2 | journal=SIAM Journal on Matrix Analysis and Applications | pages=686–706}}&amp;lt;/ref&amp;gt; 对于采用类似方式定义的各种中心性的观察也表明了这些指数之间的高阶相关性。&lt;br /&gt;
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===网络流特征Characterization by network flows==&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at once.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at oe.&lt;br /&gt;
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一个网络可以被看成是对某种物体流动的路径描述。使基于流的类型和由中心性编码的路径类型（同时）得到表征。一个流可以基于传输，每个不可分割的项目从一个节点到另一个节点，就像一个包裹从配送站送到客户的房子。第二种情况是串行复制，在这种情况下，一个项从源节点被复制到达目标节点。例如通过流言传播信息，以私有方式传播信息，并在流程结束时通知源节点和目标节点。最后一种情况是并行复制，即同时将项目复制到多个链接，就像无线电广播一次性向多个听众提供相同的信息。&lt;br /&gt;
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Likewise, the type of path can be constrained to [[Distance (graph theory)|geodesics]] (shortest paths), [[Glossary of graph theory terms#path|paths]]  (no vertex is visited more than once), [[Glossary of graph theory terms#trail|trails]] (vertices can be visited multiple times, no edge is traversed more than once), or [[Glossary of graph theory terms#walk|walks]] (vertices and edges can be visited/traversed multiple times).&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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Likewise, the type of path can be constrained to geodesics (shortest paths), paths  (no vertex is visited more than once), trails (vertices can be visited multiple times, no edge is traversed more than once), or walks (vertices and edges can be visited/traversed multiple times).&lt;br /&gt;
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同样，路径类型可以被限定为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Distance &amp;lt;/font&amp;gt;'''(最短路径)、路径(对顶点的访问不超过一次)、小径(可以访问多次顶点，没有边被访问超过一次)或者步子(可以访问/遍历多次顶点和边)。&lt;br /&gt;
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===行走结构特征Characterization by walk structure===&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either ''radial'' or ''medial.'' Radial centralities count walks which start/end from the given vertex. The [[Centrality#Degree centrality|degree]] and [[Centrality#Eigenvector centrality|eigenvalue]] centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's [[Centrality#Betweenness centrality|betweenness]] centrality, the number of shortest paths which pass through the given vertex.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either radial or medial. Radial centralities count walks which start/end from the given vertex. The degree and eigenvalue centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's betweenness centrality, the number of shortest paths which pass through the given vertex.&lt;br /&gt;
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可以从中心性的构造方式推导出另一种分类方法。这又分成了两个类。中心点可以是放射状的，也可以是内侧的。从给定顶点开始/结束的径向中心点数。度和特征值中心是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 径向中心Radial centralities&amp;lt;/font&amp;gt;'''的例子，计算长度为一或无穷大的行走的个数。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中间中心性Medial centralities&amp;lt;/font&amp;gt;'''计算通过给定顶点的步数。典型的例子是 弗里曼的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality,&amp;lt;/font&amp;gt;'''，即穿过给定顶点的最短路径的数量。&lt;br /&gt;
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Likewise, the counting can capture either the ''volume'' or the ''length'' of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's [[Centrality#Closeness centrality|closeness]] centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example.&amp;lt;ref name=Borgatti2006/&amp;gt; Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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Likewise, the counting can capture either the volume or the length of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's closeness centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example. Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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同样地，计数可以抓住行走的体积或长度。体积是给定类型的行走的总数。上一段的三个例子就属于这一类。长度则给出从给定顶点到图中其余顶点的距离。弗里曼 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，即从一个给定顶点到所有其他顶点的测地距离，是最著名的例子。请注意，这种分类独立于步行计数的类型(即：步行，小道，路径，测地线)。&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&lt;br /&gt;
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博尔加蒂和埃弗雷特提出，这种类型学为如何最好地比较中心性度量提出了建议。在这个22分类中，放在同一盒子中的中心点足够相似，可以做出合理的选择; 人们可以合理地比较哪个对于给定的应用更好。然而，不同盒子中的度量方法是截然不同的。只有在预先确定哪个类别更适用的情况下，对相对适应性的评估才会发生，这使得比较变得毫无意义。&lt;br /&gt;
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===光谱上存在的径向体积中心Radial-volume centralities exist on a spectrum===&lt;br /&gt;
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The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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步行结构的特征表明，几乎所有广泛使用的中心性都是径向体积的衡量。这得出结论顶点的中心性是与之相关联的顶点中心性的函数。中心性根据如何定义关联而不同。&lt;br /&gt;
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Bonacich showed that if association is defined in terms of [[Glossary of graph theory terms#walk|walks]], then a family of centralities can be defined based on the length of walk considered.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;/&amp;gt; [[Centrality#Degree centrality|Degree centrality]] counts walks of length one, while [[Centrality#Eigenvector centrality|eigenvalue centrality]] counts walks of length infinity. Alternative definitions of association are also reasonable. [[Alpha centrality]] allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich showed that if association is defined in terms of walks, then a family of centralities can be defined based on the length of walk considered. Degree centrality counts walks of length one, while eigenvalue centrality counts walks of length infinity. Alternative definitions of association are also reasonable. Alpha centrality allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich 指出，如果联想是根据行走来定义的，那么可以根据考虑的行走长度来定义一个中心性家族。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''计算长度为1的行走，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征值中心性Eigenvalue centrality  &amp;lt;/font&amp;gt;'''计算长度为无穷大的行走。关联的其他定义也是合理的。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 阿尔法中心性Alpha centrality&amp;lt;/font&amp;gt;'''允许顶点有一个外部影响源。埃斯特拉达的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图中心性Subgraph centrality &amp;lt;/font&amp;gt;'''提出只计算封闭路径(三角形、正方形等)。).&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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这些测量方法的核心是这种现象：图中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵&amp;lt;/font&amp;gt;'''的幂给出了由该幂给出的散步长度的数目。同样，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 矩阵指数Matrix exponential&amp;lt;/font&amp;gt;'''也与给定长度的行走次数密切相关。邻接矩阵的初始转换允许对步行计数的类型进行不同的定义。无论采用哪种方法，顶点的中心性都可以表示为无穷和&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum _ { k = 0} ^ infty a _ { r } ^ { k } beta ^ k &amp;lt;/math &amp;gt; &lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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矩阵能量或者&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum { k = 0} ^ infty frac {(a _ r beta) ^ k }{ k！{/math &amp;gt; &lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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对于矩阵指数函数，其中&lt;br /&gt;
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* &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; is walk length,&lt;br /&gt;
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* &amp;lt;math&amp;gt;A_R&amp;lt;/math&amp;gt; is the transformed adjacency matrix, and&lt;br /&gt;
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* &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; is a discount parameter which ensures convergence of the sum.&lt;br /&gt;
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K为步长，A_R是邻接矩阵的转秩，贝达是保证收敛的折扣参数。&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. [[Alpha centrality]] replaces the adjacency matrix with its [[resolvent formalism|resolvent]]. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to [[Centrality#Degree centrality|degree centrality]]. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to [[Centrality#Eigenvector centrality|eigenvalue centrality]].&amp;lt;ref name=Benzi2013/&amp;gt;&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. Alpha centrality replaces the adjacency matrix with its resolvent. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to degree centrality. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to eigenvalue centrality.&lt;br /&gt;
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博纳奇的一系列措施并没有改变邻接矩阵。阿尔法集中性用它的解决方案替代了邻接矩阵。子图集中性用它的踪迹取代了邻接矩阵。一个令人吃惊的结论是，不管邻接矩阵最初的转变是什么，所有这些方法都有共同的限制行为。随着贝塔系数趋近于零，指数收敛到度中心性。随着贝塔系数接近其最大值，指数收敛到特征值的中心性。&lt;br /&gt;
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===博弈论中心性Game-theoretic centrality===&lt;br /&gt;
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The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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上述大多数标准措施的共同特点是，它们通过只关注一个节点本身所扮演的角色来评估确定节点的重要性。然而, 在许多应用中，这种方法是不充分的，因为可能会发生协同作用&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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如果将节点的功能分组考虑。&lt;br /&gt;
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[[File:Game-theoretic centrality.png|Example of game-theoretic centrality]]&lt;br /&gt;
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Example of game-theoretic centrality&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''的例子&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in &amp;lt;ref&amp;gt;Michalak, Aadithya, Szczepański, Ravindran, &amp;amp; Jennings {{ArXiv|1402.0567}}&amp;lt;/ref&amp;gt; uses the [[Shapley value]]. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in  uses the Shapley value. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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例如，考虑阻止流行病的问题。看看上面的网络图像，我们应该给哪些节点接种疫苗？基于前面描述的措施，我们希望识别在疾病传播中最重要的节点。仅仅基于中心的方法，即关注节点的个别特性，可能不是一个好主意。红色方块中的节点，单独不能阻止疾病的传播，但把它们作为一个群体来考虑，我们清楚地看到，如果疾病在节点 &amp;lt; math &amp;gt; v _ 1 &amp;lt;/math &amp;gt; 、 &amp;lt; math &amp;gt; v _ 4 &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; v _ 5 &amp;lt;/math &amp;gt; 中开始，它们就能阻止疾病的传播。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''试图利用博弈论中的工具来研究所描述的问题和机会。本文提出的方法使用了 Shapley 值。由于 Shapley 值计算的时间复杂性，这一领域的大部分工作都集中在实现新的算法和方法，这些算法和方法依赖于网络的特殊拓扑结构或问题的特殊性质。这种方法可以将时间复杂度从指数级降低到多项式级。&lt;br /&gt;
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Similarly, the solution concept [[authority distribution]] (&amp;lt;ref&amp;gt;{{cite journal |last=Hu |first=Xingwei |first2=Lloyd |last2=Shapley |title=On Authority Distributions in Organizations |journal=Games and Economic Behavior |volume=45 |pages=132–170 |year=2003 | doi = 10.1016/s0899-8256(03)00130-1 }}&amp;lt;/ref&amp;gt;) applies the [[Shapley-Shubik power index]], rather than the [[Shapley value]], to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020)&amp;lt;ref&amp;gt;{{cite journal|last=Hu|first=Xingwei|year=2020|volume=7|title=Sorting big data by revealed preference with application to college ranking |journal=Journal of Big Data|doi=10.1186/s40537-020-00300-1|doi-access=free}}&amp;lt;/ref&amp;gt;, such as ranking U.S. colleges.&lt;br /&gt;
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Similarly, the solution concept authority distribution () applies the Shapley-Shubik power index, rather than the Shapley value, to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020), such as ranking U.S. colleges.&lt;br /&gt;
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同样，'''&amp;lt;font color=&amp;quot;#CD32CD&amp;quot;&amp;gt; 加权分布概念的解()The solution concept authority distribution () &amp;lt;/font&amp;gt;'''采用 Shapley-Shubik 幂指数，而不是 Shapley 值来衡量双方之间的直接影响。这种分布确实是一种产生'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征向量中心性Engenvector centrality&amp;lt;/font&amp;gt;'''的类型。它用于对 Hu (2020)中的大数据对象进行排序，比如美国大学排名。&lt;br /&gt;
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== 重要限制Important limitations ==&lt;br /&gt;
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Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the [[Krackhardt kite graph]], for which three different notions of centrality give three different choices of the most central vertex.&amp;lt;ref&amp;gt;{{cite journal|title=Assessing the Political Landscape: Structure, Cognition, and Power in Organizations|first=David|last=Krackhardt|authorlink=David Krackhardt|journal=Administrative Science Quarterly|volume=35|issue=2|date=June 1990|pages=342–369|doi=10.2307/2393394|jstor=2393394}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the Krackhardt kite graph, for which three different notions of centrality give three different choices of the most central vertex.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中心性Centrality&amp;lt;/font&amp;gt;'''指标有两个重要的局限性，一个显而易见，另一个则不易察觉。显而易见的局限性是，对于一个应用最优的中心性对于另一个应用常常是次优的。事实上，如果不是这样，我们就不需要这么多不同的中心性。克拉克哈特风筝图为这一现象提供了一个例证，对于这个图，三个不同的中心性概念给出了三个最中心顶点的不同选择。&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices.&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=Borgatti2005/&amp;gt; This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  [[node influence metric]]s to address this problem.&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices. This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  node influence metrics to address this problem.&lt;br /&gt;
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更不易察觉的限制是通常会错误地认为顶点中心性表示顶点的相对重要性。中心性指数被明确地设计来产生一个指出最重要顶点的排名。在刚才提到的限制下，他们做得很好。它们通常不用来测量节点的影响力。最近，网络物理学家开始开发'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;节点影响度量Node influence metrics &amp;lt;/font&amp;gt;'''来解决这个问题。&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying [[Centrality#Freeman centralization|Freeman centralization]] to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt; This approach, however, is seldom seen in practice.{{citation needed|reason=I've come across quite some theoretical studies that indicate otherwise. My suggestion is to remove this sentence, if reasonable citation is not provided.|date=September 2015}}&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying Freeman centralization to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores. This approach, however, is seldom seen in practice.&lt;br /&gt;
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错误有两方面。首先，一个排名只根据顶点的重要性排序，它并不对节点重要性的不同水平进行量化区分。这可以通过将 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;'''应用到中心性度量来缓解，这种度量可以根据节点的不同中心性得分来判断节点的重要性。此外， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;''使人们能够通过比较几个网络的最高中心性得分来比较它们。然而，这种方法在实践中很少见到。&lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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其次，用以(正确地)识别给定网络/应用中最重要顶点的特征并不一定可推广到其余顶点。&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot; /&amp;gt;&amp;lt;ref name=&amp;quot;daSilva2012&amp;quot;&amp;gt;{{cite journal | last1=da Silva|first1=Renato |last2=Viana|first2=Matheus|last3=da F. Costa |first3=Luciano| title=Predicting epidemic outbreak from individual features of the spreaders| journal=J. Stat. Mech.: Theory Exp. | year=2012|volume=2012|pages=P07005|number=7 | doi=10.1088/1742-5468/2012/07/p07005|arxiv=1202.0024|bibcode=2012JSMTE..07..005A}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Bauer2012&amp;quot;&amp;gt;{{cite journal | last1=Bauer|first1=Frank | last2=Lizier|first2=Joseph|title=Identifying influential spreaders and efficiently estimating infection numbers in epidemic models: A walk counting approach| journal=Europhys Lett | year=2012| volume=99| pages=68007|number=6 | doi=10.1209/0295-5075/99/68007|arxiv=1203.0502|bibcode=2012EL.....9968007B}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Sikic2013&amp;quot;&amp;gt;{{ cite journal| last1= Sikic| first1=Mile|last2=Lancic|first2=Alen|last3=Antulov-Fantulin|first3=Nino|last4=Stefanic|first4=Hrvoje| title = Epidemic centrality -- is there an underestimated epidemic impact of network peripheral nodes? |journal = The European Physical Journal B |volume=86 |number=10 |pages=1–13 |year=2013 | doi=10.1140/epjb/e2013-31025-5|arxiv=1110.2558 | bibcode=2013EPJB...86..440S}}&amp;lt;/ref&amp;gt; This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&amp;lt;ref name=&amp;quot;Ghoshal2011&amp;quot;&amp;gt;{{cite journal | last1=Ghoshal | first1= G. | last2= Barabsi |first2= A L | title = Ranking stability and super-stable nodes in complex networks. | journal = Nat Commun | volume =2 | page = 394| year= 2011 | doi=10.1038/ncomms1396 | pmid= 21772265 | bibcode=2011NatCo...2..394G | doi-access= free }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless. This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&lt;br /&gt;
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对于大多数其他网络节点，排名可能是没有意义的。这就解释了为什么，例如，只有谷歌图片搜索的前几个结果以合理的顺序出现。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页排名Pagerank&amp;lt;/font&amp;gt;'''是一个非常不稳定的度量，显示了在跳转参数小的调整之后频繁的秩逆转。&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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虽然中心性指数未能推广到网络的其他部分，乍看起来似乎是违反直觉的，但它直接遵循上述定义。&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot;&amp;gt;{{cite journal |last1= Lawyer |first1= Glenn |year= 2015 |title= Understanding the spreading power of all nodes in a network: a continuous-time perspective |journal=Sci Rep |volume=5|pages=8665|doi=10.1038/srep08665 |pmid=25727453 |pmc=4345333|arxiv=1405.6707|bibcode=2015NatSR...5E8665L}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&lt;br /&gt;
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复杂网络具有异构的拓扑结构。由于最佳度量取决于最重要顶点的网络结构，对于这些顶点最优的度量对于网络的其余部分是次优的。&lt;br /&gt;
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==Degree centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Degree (graph theory)}} &lt;br /&gt;
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[[File:6 centrality measures.png|thumb|right|300px|Examples of A) [[Betweenness centrality]], B) [[Closeness centrality]], C) [[Eigenvector centrality]], D) [[Degree centrality]], E) [[Centrality#Harmonic centrality|Harmonic centrality]] and F) [[Katz centrality]] of the same graph.]]&lt;br /&gt;
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Examples of A) [[Betweenness centrality, B) Closeness centrality, C) Eigenvector centrality, D) Degree centrality, E) Harmonic centrality and F) Katz centrality of the same graph.]]&lt;br /&gt;
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实例 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; a)[中介中心性A) [[Betweenness centrality,b)紧密中心性，B) Closeness centrality, c)特征向量中心性，C) Eigenvector centrality, d)度中心性，D) Degree centrality, e)调和中心性，E) Harmonic centrality andf) 卡兹Katz 中心性]F) Katz centrality .]]&amp;lt;/font&amp;gt;'''&lt;br /&gt;
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Historically first and conceptually simplest is '''degree centrality''', which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely [[indegree]] and [[outdegree]]. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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Historically first and conceptually simplest is degree centrality, which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely indegree and outdegree. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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历史上最简单的概念是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''，它定义为一个节点上发生的链接数量(即一个节点拥有的关系数量)。度可以根据节点捕获流经网络的任何东西(例如病毒或某些信息)的直接风险来解释。在有向网络的情况下(其中联系有方向) ，我们通常定义两个独立的度量，即 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度 Outdegree&amp;lt;/font&amp;gt;'''。因此，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度indegree&amp;lt;/font&amp;gt;'''是指向该节点的关系数，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度outdegree&amp;lt;/font&amp;gt;'''是指该节点指向其他节点的关系数。当关系与一些积极的方面如友谊或合作有关时， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''通常被解释为一种形式的受欢迎，而 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度Indegree&amp;lt;/font&amp;gt;'''则被解释为合群。&lt;br /&gt;
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The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
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The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
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对于给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边，度的中心性定义为&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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Calculating degree centrality for all the nodes in a graph takes [[big theta|&amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt;]] in a [[dense matrix|dense]] [[adjacency matrix]] representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a [[sparse matrix]] representation.&lt;br /&gt;
&lt;br /&gt;
Calculating degree centrality for all the nodes in a graph takes &amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt; in a dense adjacency matrix representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a sparse matrix representation.&lt;br /&gt;
&lt;br /&gt;
计算一个图中所有节点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''需要在图的稠密'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵Adjacency matrix &amp;lt;/font&amp;gt;'''表示中使用 Theta (v ^ 2) &amp;lt;/math &amp;gt; ，而在稀疏矩阵表示中使用 Theta (e) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of ''graph centralization''.&amp;lt;ref&amp;gt;Freeman, Linton C. &amp;quot;Centrality in social networks conceptual clarification.&amp;quot; Social networks 1.3 (1979): 215–239.&amp;lt;/ref&amp;gt; Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
&lt;br /&gt;
The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of graph centralization. Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
&lt;br /&gt;
节点级中心性的定义可以扩展到整个图，在这种情况下，我们指的是图的集中性。设 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 为 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''最高的节点。让 &amp;lt; math &amp;gt; x: = (y，z) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; | y | &amp;lt;/math &amp;gt; 节点连接图，最大化下列数量(&amp;lt; math &amp;gt; y * &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 中度最高的节点) :&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h = sum ^ { | y | }{ j = 1}[ c _ d (y *)-c _ d (y _ j)] &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
&lt;br /&gt;
Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
&lt;br /&gt;
相应地，图形 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''如下:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ h } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a [[star graph]]), and in this case&lt;br /&gt;
&lt;br /&gt;
The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a star graph), and in this case&lt;br /&gt;
&lt;br /&gt;
当图形 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 包含一个所有其他节点都连接的中心节点(一个星形图)时，&amp;lt; math &amp;gt; h &amp;lt;/math &amp;gt; 的值最大化，在这种情况下&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
(n-1)-1) = n ^ 2-3n + 2&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
所以，对于任意的图 &amp;lt; math &amp;gt; g: = (v，e) ，&amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ | v | ^ 2-3 | v | + 2} &amp;lt;/math &amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Closeness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Closeness centrality}}In a [[Connected component (graph theory)|connected]] [[Graph (discrete mathematics)|graph]], the [[Normalization (statistics)|normalized]] '''closeness centrality''' (or '''closeness''') of a node is the average length of the [[Shortest path problem|shortest path]] between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
&lt;br /&gt;
In a connected graph, the normalized closeness centrality (or closeness) of a node is the average length of the shortest path between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
&lt;br /&gt;
在连通图中，节点的标准'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''(或贴近性)是节点与图中所有其他节点之间最短路径的平均长度。因此，一个节点越是中心，它就越接近所有其他节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Closeness was defined by [[Alex Bavelas]] (1950) as the [[Multiplicative inverse|reciprocal]] of the '''farness''',&amp;lt;ref&amp;gt;Alex Bavelas. Communication patterns in task-oriented groups. ''J. Acoust. Soc. Am'', '''22'''(6):725–730, 1950.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;{{cite journal|year=1966|title=The centrality index of a graph|url=|journal=Psychometrika|volume=31|issue=4|pages=581–603|doi=10.1007/bf02289527|pmid=5232444|hdl=10338.dmlcz/101401|last1=Sabidussi|first1=G|hdl-access=free}}&amp;lt;/ref&amp;gt; that is:&lt;br /&gt;
&lt;br /&gt;
Closeness was defined by Alex Bavelas (1950) as the reciprocal of the farness, that is:&lt;br /&gt;
&lt;br /&gt;
亚历克斯 · 巴维拉斯(1950)将亲密度定义为相对于距离的倒数，即:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
C (x) = frac {1}{ sum _ y d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the [[Distance (graph theory)|distance]] between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the distance between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; d (y，x) &amp;lt;/math &amp;gt; 是顶点 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; 之间的距离。然而，当谈到'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''时，人们通常会提到它的标准化形式，一般是以前的公式乘以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; ，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。这种调整允许比较不同大小图形的节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Taking distances ''from'' or ''to'' all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in [[directed graph]]s (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
&lt;br /&gt;
Taking distances from or to all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in directed graphs (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
&lt;br /&gt;
从所有其他节点或到所有其他节点的距离在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 无向图Undirected graphs&amp;lt;/font&amp;gt;'''中是不相关的，但是在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 有向图Directed graphs&amp;lt;/font&amp;gt;'''中可能产生完全不同的结果(例如:一个网站可以从传出链接获得高的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，而从传入链接获得低的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''）。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
===Harmonic centrality===&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the '''harmonic centrality''' reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the harmonic centrality reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
在一个(不一定是连通的)图中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''反转了'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''定义中的和互反运算:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h (x) = sum { y neq x } frac {1}{ d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; 1/d (y，x) = 0 &amp;lt;/math &amp;gt; if there is no path from &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; to &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 。调和中心性可以通过除以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; 来标准化，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Harmonic centrality was proposed by [[Massimo Marchiori|Marchiori]] and [[Vito Latora|Latora]] (2000)&amp;lt;ref name=&amp;quot;marchiorilatora2000&amp;quot;&amp;gt;{{citation| journal = Physica A: Statistical Mechanics and Its Applications  | last1 = Marchiori | first1 = Massimo | last2 = Latora | first2 = Vito | year = 2000 | volume = 285 | issue = 3–4 | pages = 539–546 | title = Harmony in the small-world | doi=10.1016/s0378-4371(00)00311-3| arxiv = cond-mat/0008357 | bibcode = 2000PhyA..285..539M }}&amp;lt;/ref&amp;gt; and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot;&amp;lt;ref&amp;gt;{{cite journal|first1=Anthony|last1=Dekker|title=Conceptual Distance in Social Network Analysis|journal=Journal of Social Structure|volume=6|issue=3|year=2005|url=http://www.cmu.edu/joss/content/articles/volume6/dekker/index.html}}&amp;lt;/ref&amp;gt; and by Rochat (2009).&amp;lt;ref&amp;gt;{{cite conference  | author = Yannick Rochat  | title = Closeness centrality extended to unconnected graphs: The harmonic centrality index | conference = Applications of Social Network Analysis, ASNA 2009 | url = http://infoscience.epfl.ch/record/200525/files/%5bEN%5dASNA09.pdf }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Harmonic centrality was proposed by Marchiori and Latora (2000) and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot; and by Rochat (2009).&lt;br /&gt;
&lt;br /&gt;
调和中心性是由 Marchiori 和 Latora (2000)提出的，然后是 Dekker (2005)独立提出的，使用的名称是“有价值的中心性” ，Rochat (2009)。&lt;br /&gt;
&lt;br /&gt;
==Betweenness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Betweenness centrality}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Graph betweenness.svg|240px|right|thumb|Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.]]&lt;br /&gt;
&lt;br /&gt;
Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.&lt;br /&gt;
&lt;br /&gt;
色调(从红色 = 0到蓝色 = max)表示节点之间的距离。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
'''Betweenness''' is a centrality measure of a [[vertex (graph theory)|vertex]] within a [[Graph (discrete mathematics)|graph]] (there is also [[edge (graph theory)|edge]] betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by [[Linton Freeman]]&amp;lt;ref name=&amp;quot;freeman1977&amp;quot;&amp;gt;{{cite journal |last1 = Freeman |first1 = Linton | year=1977| title = A set of measures of centrality based upon betweenness | journal = Sociometry| volume=40|issue = 1 | pages=35–41 | doi=10.2307/3033543|jstor = 3033543 }}&amp;lt;/ref&amp;gt; In his conception, vertices that have a high probability to occur on a randomly chosen [[shortest path problem|shortest path]] between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
&lt;br /&gt;
Betweenness is a centrality measure of a vertex within a graph (there is also edge betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by Linton Freeman In his conception, vertices that have a high probability to occur on a randomly chosen shortest path between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
&lt;br /&gt;
中介性是图中顶点的中心性度量(也有边中介性，这里没有讨论)。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''量化了一个节点沿着其他两个节点之间的最短路径充当桥梁的次数。在林顿 · 弗里曼的概念中，在两个随机选择的顶点之间随机选择的最短路径上出现概率高的顶点具有很高的中介性。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
&lt;br /&gt;
The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
&lt;br /&gt;
在一个图 &amp;lt; math &amp;gt; g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的顶点之间的距离计算如下:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
# For each pair of vertices (''s'',''t''), compute the [[Shortest path problem|shortest paths]] between them.&lt;br /&gt;
&lt;br /&gt;
 For each pair of vertices (s,t), compute the shortest paths between them.&lt;br /&gt;
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对于每一对顶点(s，t) ，计算它们之间的最短路径。&lt;br /&gt;
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# For each pair of vertices (''s'',''t''), determine the fraction of shortest paths that pass through the vertex in question (here, vertex ''v'').&lt;br /&gt;
&lt;br /&gt;
 For each pair of vertices (s,t), determine the fraction of shortest paths that pass through the vertex in question (here, vertex v).&lt;br /&gt;
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对于每对顶点(s，t) ，确定通过该顶点(这里是顶点 v)的最短路径的分数。&lt;br /&gt;
&lt;br /&gt;
# Sum this fraction over all pairs of vertices (''s'',''t'').&lt;br /&gt;
&lt;br /&gt;
 Sum this fraction over all pairs of vertices (s,t).&lt;br /&gt;
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对所有顶点对(s，t)求这个分数的和。&lt;br /&gt;
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More compactly the betweenness can be represented as:&amp;lt;ref name=&amp;quot;brandes&amp;quot;&amp;gt;{{cite journal |last1 = Brandes |first1 = Ulrik | year=2001 |title = A faster algorithm for betweenness centrality  | journal = Journal of Mathematical Sociology| volume=25|issue = 2 | pages=163–177| url = http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.11.2024 | accessdate = October 11, 2011| format = PDF | doi=10.1080/0022250x.2001.9990249|citeseerx = 10.1.1.11.2024 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
More compactly the betweenness can be represented as:&lt;br /&gt;
&lt;br /&gt;
更确切地说，两者之间的关系可以表示为:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
{ math &amp;gt; c _ b (v) = sum _ { s neq v neq t in v } frac { sigma _ st }(v)}{ sigma _ st } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including ''v'', which for [[Digraph (mathematics)|directed graphs]] is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected [[Star (graph theory)|star graph]], the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including v, which for directed graphs is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected star graph, the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; sigma { st } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { st }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径数。有向图是 &amp;lt; math &amp;gt; (n-1)(n-2) &amp;lt;/math &amp;gt; ，无向图是 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; 。例如，在一个无向星图中，中心顶点(包含在每个可能的最短路径中)的中介性为 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; (1，如果标准化) ，而叶子(包含在没有最短路径中)的中介性为0。&lt;br /&gt;
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&lt;br /&gt;
&lt;br /&gt;
From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires [[Big O notation|&amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt;]] time with the [[Floyd–Warshall algorithm]]. However, on sparse graphs, [[Johnson's algorithm]] may be more efficient, taking [[Big O notation|&amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt;]] time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm&amp;lt;ref name=brandes/&amp;gt; which takes [[Big O notation|&amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt;]] time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&amp;lt;ref name=&amp;quot;brandes&amp;quot; /&amp;gt;&lt;br /&gt;
&lt;br /&gt;
From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires &amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt; time with the Floyd–Warshall algorithm. However, on sparse graphs, Johnson's algorithm may be more efficient, taking &amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt; time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm which takes &amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt; time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&lt;br /&gt;
&lt;br /&gt;
从计算的角度来看，图中所有顶点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介和紧密中心性Betweenness and Closeness centralities&amp;lt;/font&amp;gt;'''都涉及到计算图中所有顶点对之间的最短路径，这就需要用 Floyd-Warshall 算法计算时间。然而，对于稀疏图，约翰逊算法的效率可能更高，采用 &amp;lt; math &amp;gt; o (v ^ 2 log v + v e) &amp;lt;/math &amp;gt; 时间。在不加权图的情况下，可以用 Brandes 的算法进行计算，该算法需要 &amp;lt; math &amp;gt; o (v e) &amp;lt;/math &amp;gt; 时间。一般情况下，这些算法假定图是无向的，并且连通图中允许有圈和多条边。当专门处理网络图时，图通常没有环或多条边来维持简单的关系(其中的边表示两个人或顶点之间的联系)。在这种情况下，使用 Brandes 的算法将最终的中心性分数除以2来计算每条被重复计算的最短路径。&lt;br /&gt;
&lt;br /&gt;
==Eigenvector centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Eigenvector centrality}}&lt;br /&gt;
&lt;br /&gt;
'''Eigenvector centrality''' (also called '''eigencentrality''') is a measure of the influence of a [[node (networking)|node]] in a [[network (mathematics)|network]]. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&amp;lt;ref&amp;gt;{{cite journal|title = The mathematics of networks|url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf|author = M. E. J. Newman|accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;/&amp;gt; [[Google]]'s [[PageRank]] and the [[Katz centrality]] are variants of the eigenvector centrality.&amp;lt;ref name=&amp;quot;ams&amp;quot;&amp;gt;{{Cite web | url=http://www.ams.org/samplings/feature-column/fcarc-pagerank | title=American Mathematical Society}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Eigenvector centrality (also called eigencentrality) is a measure of the influence of a node in a network. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''(也称为特征中心性)是衡量网络中节点影响的一个指标。它将相对得分分配给网络中的所有节点，这是基于这样一个概念: 与得分较高的节点相比，与得分较低的节点相同的连接对所涉及的节点的得分贡献更大。&lt;br /&gt;
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=== Using the adjacency matrix to find eigenvector centrality ==&lt;br /&gt;
==使用'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''发现'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the [[adjacency matrix]], i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
&lt;br /&gt;
For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the adjacency matrix, i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
&lt;br /&gt;
对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 让 &amp;lt; math &amp;gt; a = (a { v，t }) &amp;lt;/math &amp;gt; 成为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''，即。如果顶点 &amp;lt; math &amp;gt; &amp;gt; v &amp;lt;/math &amp;gt; 与 math &amp;gt; t &amp;lt;/math &amp;gt; 相连，而 &amp;lt; math &amp;gt; a { v，t } = 0 &amp;lt;/math &amp;gt; 否则。顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分可以定义为:&lt;br /&gt;
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&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
在 m (v)} x _ t = frac {1}{ lambda } sum { t in g } a { v，t } x _ t &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the [[eigenvector]] equation&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the eigenvector equation&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; m (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 和 &amp;lt; math &amp;gt; &amp;gt; lambda &amp;lt;/math &amp;gt; 的邻居集合。通过一个小的重新排列，这可以被重写成向量符号，作为特征向量方程&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[ math &amp;gt; mathbf { Ax } = { lambda } mathbf { x } &amp;lt;/math &amp;gt; &lt;br /&gt;
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In general, there will be many different [[eigenvalue]]s &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the [[Perron–Frobenius theorem]]. This greatest eigenvalue results in the desired centrality measure.&amp;lt;ref&amp;gt;{{cite journal  | author = M. E. J. Newman  | title = The mathematics of networks  | url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf  | accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt; The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices ''n''. [[Power iteration]] is one of many [[eigenvalue algorithm]]s that may be used to find this dominant eigenvector.&amp;lt;ref name=&amp;quot;ams&amp;quot; /&amp;gt; Furthermore, this can be generalized so that the entries in ''A'' can be real numbers representing connection strengths, as in a [[stochastic matrix]].&lt;br /&gt;
&lt;br /&gt;
In general, there will be many different eigenvalues &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the Perron–Frobenius theorem. This greatest eigenvalue results in the desired centrality measure. The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices n. Power iteration is one of many eigenvalue algorithms that may be used to find this dominant eigenvector. Furthermore, this can be generalized so that the entries in A can be real numbers representing connection strengths, as in a stochastic matrix.&lt;br /&gt;
&lt;br /&gt;
一般情况下，存在许多不同的特征值，对于这些特征值存在一个非零特征向量解。由于邻接矩阵中的条目是非负的，所以由 Perron-弗罗贝尼乌斯定理得出，它有一个实的和正的唯一最大特征值。由这个最大的特征值得出期望的中心性度量。相关特征向量的 &amp;lt; math &amp;gt; v ^ { th } &amp;lt;/math &amp;gt; 分量给出了网络中顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分。特征向量只定义了一个公共因子，所以只有顶点中心的比例是明确定义的。要定义一个绝对分数，必须对特征向量进行标准化，例如，使所有顶点的和为1或顶点的总数n。此外，这可以通用，使得 a 中的条目可以是表示连接强度的真实数字，就像'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 随机矩阵Stochastic matrix&amp;lt;/font&amp;gt;'''中一样。&lt;br /&gt;
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==Katz centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Katz centrality}}&lt;br /&gt;
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'''Katz centrality'''&amp;lt;ref&amp;gt;Katz, L. 1953. A New Status Index Derived from Sociometric Index. Psychometrika, 39–43.&amp;lt;/ref&amp;gt; is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
Katz centrality is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''是度中心性的推广。度中心性度量的是直接邻居的数量，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''度量的是通过一条路径可以连接的所有节点的数量，而远处节点的贡献会受到'''&amp;lt;font color=&amp;quot;#32CD32&amp;quot;&amp;gt; '削弱（惩罚？）Penalized&amp;lt;/font&amp;gt;''。在数学上，它被定义为&lt;br /&gt;
&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[数学][数学]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; (0,1) &amp;lt;/math &amp;gt; 中的衰减因子。&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''可以看作是特征向量中心性的变体。Katz 中心性的另一种形式是&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
(x _ j + 1) &lt;br /&gt;
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Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
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Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
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与特征向量中心性的表达式相比，&amp;lt; math &amp;gt; x _ j &amp;lt;/math &amp;gt; 被 &amp;lt; math &amp;gt; x _ j + 1所代替&lt;br /&gt;
&lt;br /&gt;
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It is shown that&amp;lt;ref&amp;gt;{{cite journal | last1 = Bonacich | first1 = P | year = 1991 | title = Simultaneous group and individual centralities | url = | journal = Social Networks | volume = 13 | issue = 2| pages = 155–168 | doi=10.1016/0378-8733(91)90018-o}}&amp;lt;/ref&amp;gt; the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
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It is shown that the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
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结果表明，主特征向量(与 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; ，邻接矩阵的最大特征值相关)是 Katz 中心性的极限，因为 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 接近 &amp;lt; math &amp;gt; tfrac {1}{ lambda } &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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== PageRank centrality ==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页分布中心性PageRank&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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{{main|PageRank}}'''[[PageRank]]''' satisfies the following equation&lt;br /&gt;
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PageRank satisfies the following equation&lt;br /&gt;
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PageRank满足下面的等式&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
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1-alpha { n } ，&amp;lt;/math &amp;gt; &lt;br /&gt;
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&lt;br /&gt;
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where&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
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其中&lt;br /&gt;
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&lt;br /&gt;
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:&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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[ math &amp;gt; l (j) = sum { i } a { ji } &amp;lt;/math &amp;gt; &lt;br /&gt;
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is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&amp;lt;ref&amp;gt;[http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf How does Google rank webpages?] {{webarchive | url= https://web.archive.org/web/20120131083328/http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf |date=January 31, 2012 }} 20Q: About Networked Life&amp;lt;/ref&amp;gt;&lt;br /&gt;
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is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&lt;br /&gt;
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是节点 &amp;lt; math &amp;gt; j &amp;lt;/math &amp;gt; (或有向图中出站链接的数量)的邻居数量。与特征向量中心性和 Katz 中心性相比，尺度因子 &amp;lt; math &amp;gt; l (j) &amp;lt;/math &amp;gt; 是一个主要的区别。PageRank 和特征向量中心性的另一个区别是 PageRank 向量是一个左手特征向量(注意因子 &amp;lt; math &amp;gt; a _ { ji } &amp;lt;/math &amp;gt; 具有相反的索引)。&lt;br /&gt;
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==Percolation centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&amp;lt;ref name=&amp;quot;piraveenan2013&amp;quot;&amp;gt;{{cite journal |last1 = Piraveenan |first1 = M. |last2 = Prokopenko |first2 = M.|last3 = Hossain|first3 = L. |year=2013| title = Percolation Centrality: Quantifying Graph-Theoretic Impact of Nodes during Percolation in Networks | journal = PLOS One | volume=8 | issue=1 | doi=10.1371/journal.pone.0053095 | pages=e53095 | pmid=23349699 | pmc=3551907| bibcode=2013PLoSO...853095P }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&lt;br /&gt;
&lt;br /&gt;
在复杂网络中，存在大量的中心性度量来确定单个节点的“重要性”。然而，这些度量单纯从拓扑学的角度来量化节点的重要性，节点的值并不以任何方式依赖于节点的状态。不管网络动态如何，它都保持不变。即使对于加权的两者之间的度量也是如此。然而，一个节点可能很好地位于'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''或其他中心性度量的中心位置，但可能不是位于有过滤的网络的上下文中的中心位置。在许多情况下，复杂网络中都会出现“传染”现象。例如，病毒或细菌感染可以通过人们的社交网络传播，也就是所谓的接触网络。还可以在更高的抽象层次上考虑疾病的传播问题，设想通过公路、铁路或空中连接起来的城镇或人口中心网络。计算机病毒可以通过计算机网络传播。关于商业活动和交易的谣言或新闻也可以通过人们的社交网络传播。在所有这些情况下，一种“传染病”在一个复杂网络的链接上传播，随着它的传播，无论是可恢复的还是不可恢复的，都会改变节点的“状态”。例如，在流行病学方案中，随着感染扩散，个人从”易感”状态转变为”受感染”状态。在上面的例子中，随着传染的扩散，每个节点可以采取的状态可以是二进制的(例如接收/没有接收到一条新闻)、离散的(易感/受感染/康复) ，甚至是连续的(例如一个城镇中受感染的人的比例) 。这些情景的共同特点是，传染的扩散导致网络中节点状态的改变。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''（PC)就是基于这个思想而提出的，它特别地衡量了节点在协助网络渗滤方面的重要性。这项措施是由 piraveanan 等人提出的。&lt;br /&gt;
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'''Percolation centrality''' is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
&lt;br /&gt;
Percolation centrality is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''定义为在给定时间内一个给定节点的过滤路径的比例。“渗滤路径”是一对节点之间的最短路径，其中源节点被渗滤(例如，被感染)。目标节点可以是过滤的或非过滤的，或处于部分过滤状态。&lt;br /&gt;
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&lt;br /&gt;
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:&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; PC ^ t (v) = frac {1}{ N-2} sum { s neq v neq r } frac { sigma { sr }(v)}{ sigma { sr }} frac { x ^ t }{ sum {[{ x ^ t } i }}}]}}-{ x ^ t }{ v } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; σ { sr } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; r &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { sr }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径的总数。在时间 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 时，节点的过滤状态用 &amp;lt; math &amp;gt; { x ^ t } _ i &amp;lt;/math &amp;gt; 表示，两个特殊情况是当 &amp;lt; math &amp;gt; { x ^ t } _ i = 0 &amp;lt;/math &amp;gt; 表示在时间上是非过滤状态，而当 &amp;lt; math &amp;gt; &amp;lt; x ^ t &amp;lt;/math &amp;gt; i = 1 &amp;lt;/math &amp;gt; 表示在时间上是完全过滤状态。两者之间的值表示部分过滤状态(例如，在一个城镇网络中，这是该城镇感染者的百分比)。&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in [[Big O notation|&amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt;]] time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is [[Big O notation|&amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;]].&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in &amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt; time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is &amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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渗流路径的权重取决于分配给源节点的渗流水平，前提是源节点的渗流水平越高，源节点的路径就越重要。因此，位于源自高渗滤节点的最短路径上的节点可能对渗滤更为重要。PC 的定义也可以扩展到包括目标节点的权重。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''计算运行在 &amp;lt; math &amp;gt; o (NM) &amp;lt;/math &amp;gt; 时间，采用了 Brandes 快速算法的有效实现，如果计算需要考虑目标节点的权重，最坏情况下时间为 &amp;lt; math &amp;gt; o (n ^ 3) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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==Cross-clique centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 交叉团中心性Cross-clique centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
'''Cross-clique centrality''' of a single node in a complex graph determines the connectivity of a node to different [[clique (graph theory)|clique]]s. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in &amp;lt;ref name=&amp;quot;xssworms&amp;quot;&amp;gt;{{cite journal |last1 = Faghani|first1 = Mohamamd Reza| year=2013| title = A Study of XSS Worm Propagation and Detection Mechanisms in Online Social Networks | journal = IEEE Transactions on Information Forensics and Security|volume = 8|issue = 11|pages = 1815–1826|doi = 10.1109/TIFS.2013.2280884}}&amp;lt;/ref&amp;gt; but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
&lt;br /&gt;
Cross-clique centrality of a single node in a complex graph determines the connectivity of a node to different cliques. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in  but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
&lt;br /&gt;
复杂图中单个节点的跨团中心性决定了一个节点与不同团的连通性。具有高度跨团连通性的节点有利于信息或疾病在图中的传播。团是一种'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图Subgraphs&amp;lt;/font&amp;gt;'''，团中的每个节点都与团中的其他节点相连。对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边的交叉团连通性，定义为 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; x (v) &amp;lt;/math &amp;gt; 其中 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 所属的顶点团数。这个测度应用日久，但是在1998年由 Everett 和 Borgatti 首次提出，他们称之为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 派系重叠中心性Clique-overlap centrality&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
&lt;br /&gt;
==Freeman centralization==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心度Freeman centralization&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
The '''centralization''' of any network is a measure of how central its most central node is in relation to how central all the other nodes are.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;&amp;gt;{{citation | journal = Social Networks | last1 = Freeman | first1 = Linton C. | year = 1979 | volume = 1 | issue = 3 | pages = 215–239 | title = centrality in social networks: Conceptual clarification | url = http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | doi = 10.1016/0378-8733(78)90021-7 | citeseerx = 10.1.1.227.9549 | access-date = 2014-07-31 | archive-url = https://web.archive.org/web/20160222033108/http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | archive-date = 2016-02-22 | url-status = dead }}&amp;lt;/ref&amp;gt; Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
&lt;br /&gt;
The centralization of any network is a measure of how central its most central node is in relation to how central all the other nodes are. Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
&lt;br /&gt;
任何网络的集中度都是衡量其最核心的节点相对于其他所有节点的集聚程度的标准。集中度的度量方法是: (a)计算网络中最中心的节点与所有其他节点之间的中心性差异之和; (b)将这个数量除以理论上相同规模的任何网络中这种差异之和的最大值。因此，每个中心性度量都可以有自己的集中性度量。正式定义，如果 &amp;lt; math &amp;gt; c _ x (p _ i) &amp;lt;/math &amp;gt; 是点 &amp;lt; math &amp;gt; i &amp;lt;/math &amp;gt; 的中心性度量，如果 &amp;lt; math &amp;gt; c _ x (p _ *) &amp;lt;/math &amp;gt; 是网络中最大的中心性度量，如果:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; max sum { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i) &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&lt;br /&gt;
&lt;br /&gt;
对于任何具有相同节点数的图来说，点中心性的最大差异是:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ x = frac { sum _ { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i)}{ max sum _ { i = 1 ^ { n } c _ x (p _ *)-c _ x (p _ i)} . &amp;lt;/math &amp;gt;&lt;br /&gt;
&lt;br /&gt;
== Dissimilarity based centrality measures ==&lt;br /&gt;
==基于相异性的中心性度量==&lt;br /&gt;
&lt;br /&gt;
[[File:Srep17095-f1.jpg|thumbnail|In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.]]&lt;br /&gt;
&lt;br /&gt;
In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.&lt;br /&gt;
&lt;br /&gt;
在图示的网络中，绿色节点和红色节点最不相似，因为它们之间不共享相邻节点。因此，绿色的节点比灰色的节点对中心性的贡献更大，因为红色的节点只能通过绿色访问蓝色的节点，而灰色的节点对于红色的节点是多余的，因为它可以直接访问每个灰色的节点，而不需要任何中介。&lt;br /&gt;
&lt;br /&gt;
In order to obtain better results in the ranking of the nodes of a given network,  in &amp;lt;ref&amp;gt;{{Cite journal|title = Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|journal = Scientific Reports|date = 2015-11-25|pmc = 4658528|pmid = 26603652|volume = 5|doi = 10.1038/srep17095|first = A. J.|last = Alvarez-Socorro|first2 = G. C.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz|pages=17095|bibcode = 2015NatSR...517095A}}&amp;lt;/ref&amp;gt; are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with [[eigenvector centrality]], calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
&lt;br /&gt;
In order to obtain better results in the ranking of the nodes of a given network,  in  are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with eigenvector centrality, calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
&lt;br /&gt;
为了在给定网络节点的排序中获得更好的结果，在复杂网络中使用了相异性度量(特定于分类和数据挖掘理论)来丰富中心性度量。特征向量中心性通过求解特征值问题来计算每个节点的中心性&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
数学，数学&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary [[Matrix similarity|dissimilarity]] matrix, defined through a dissimilitary measure, e.g., [[Jaccard index|Jaccard]] dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary dissimilarity matrix, defined through a dissimilitary measure, e.g., Jaccard dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
这里 &amp;lt; math &amp;gt; w { ij } = a { ij } d { ij } &amp;lt;/math &amp;gt; (coordinate-to-coordinate product)和 &amp;lt; math &amp;gt; d { ij } &amp;lt;/math &amp;gt; 是一个任意的不相似矩阵，通过一个双重军事度量来定义，例如，Jaccard 由&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1-dfrac { | v ^ { + }(i) cap v ^ { + }(j) | }{ | v ^ { + }(i) cup v ^ { + }(j) | } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
&lt;br /&gt;
Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
&lt;br /&gt;
这种度量允许我们量化每个节点对给定节点中心性的拓扑贡献(这就是为什么我们称之为贡献中心性) ，对那些相异性较大的节点有更多的权重/相关性，因为这些节点允许给定的节点访问那些它们自己不能直接访问的节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the [[Perron–Frobenius theorem]] to ensure that the above problem has a unique solution for ''λ'' = ''λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt;'' with '''c''' non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
&lt;br /&gt;
Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the Perron–Frobenius theorem to ensure that the above problem has a unique solution for λ = λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt; with c non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
&lt;br /&gt;
值得注意的是，&amp;lt; math &amp;gt; w &amp;lt;/math &amp;gt; 是非负的，因为 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; d &amp;lt;/math &amp;gt; 都是非负矩阵，所以我们可以使用 Perron 弗罗贝尼乌斯定理来确保上述问题对于 c 非负的 = &amp;lt; sub &amp;gt; max &amp;lt;/sub &amp;gt; 有唯一的解，这样我们就可以推断出网络中每个节点的中心性。因此，i-th 节点的中心性为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1{ n } sum { j = 1} ^ { n } w { ij } c { j } ，，，，，j = 1，cdots，n &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in &amp;lt;ref&amp;gt;{{Cite web|url = http://www.nature.com/article-assets/npg/srep/2015/151125/srep17095/extref/srep17095-s1.pdf|title = Supplementary Information for Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|date = |website = |publisher = Nature Publishing Group|last = Alvarez-Socorro|first = A.J.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz}}&amp;lt;/ref&amp;gt; obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in  obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是网络中的节点数。几个不同的措施和网络进行了测试，以获得在研究案例的改善的结果。&lt;br /&gt;
&lt;br /&gt;
==Extensions==&lt;br /&gt;
==扩展==&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality&amp;lt;ref&amp;gt;{{cite journal | last1 = Braha | first1 = D. | last2 = Bar-Yam | first2 = Y. | year = 2006 | title = From Centrality to Temporary Fame: Dynamic Centrality in Complex Networks | url = | journal = Complexity | volume = 12 | issue = 2| pages = 59–63 | doi=10.1002/cplx.20156| arxiv = physics/0611295 | bibcode = 2006Cmplx..12b..59B }}&amp;lt;/ref&amp;gt; in the context of time-dependent and temporal networks.&amp;lt;ref&amp;gt;{{cite journal | last1 = Hill | first1 = S.A. | last2 = Braha | first2 = D. | year = 2010 | title = Dynamic Model of Time-Dependent Complex Networks | url = | journal = Physical Review E | volume = 82 | issue = 4| page = 046105 | doi=10.1103/physreve.82.046105| pmid = 21230343 | arxiv = 0901.4407 | bibcode = 2010PhRvE..82d6105H }}&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Gross, T. and Sayama, H. (Eds.). 2009. ''Adaptive Networks: Theory, Models and Applications.'' Springer.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Holme, P. and Saramäki, J. 2013. ''Temporal Networks.'' Springer.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality in the context of time-dependent and temporal networks.&lt;br /&gt;
&lt;br /&gt;
经验和理论研究已经将静态网络中的中心性概念扩展到时间依赖网络和时间网络中的动态中心性。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&amp;lt;ref&amp;gt;{{cite journal | last1 = Opsahl | first1 = Tore | last2 = Agneessens | first2 = Filip | last3 = Skvoretz | first3 = John | title = Node centrality in weighted networks: Generalizing degree and shortest paths | doi = 10.1016/j.socnet.2010.03.006 | year = 2010 | pages = 245–251 | volume = 32 | journal = Social Networks | url = http://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | issue = 3 | access-date = 2010-04-23 | archive-url = https://web.archive.org/web/20180226080331/https://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | archive-date = 2018-02-26 | url-status = dead }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&lt;br /&gt;
&lt;br /&gt;
对加权网络的推广，见 Opsahl 等人。(2010).&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, '''group betweenness''' centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&amp;lt;ref name=&amp;quot;group1&amp;quot;&amp;gt;Everett, M. G. and Borgatti, S. P. (2005). Extending centrality. In P. J. Carrington, J. Scott and S. Wasserman (Eds.), ''Models and methods in social network analysis'' (pp. 57–76). New York: Cambridge University Press.&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;group2&amp;quot;&amp;gt;Puzis, R., Yagil, D., Elovici, Y., Braha, D. (2009).[http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf Collaborative attack on Internet users’ anonymity] {{Webarchive|url=https://web.archive.org/web/20131207133417/http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf |date=2013-12-07 }}, ''Internet Research'' '''19'''(1)&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, group betweenness centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&lt;br /&gt;
&lt;br /&gt;
中心性的概念也扩展到了群体层次。例如，组间的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''显示了连接穿过组的成对非组成员的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Geodesics &amp;lt;/font&amp;gt;'''的比例。&lt;br /&gt;
&lt;br /&gt;
==See also==&lt;br /&gt;
==又及==&lt;br /&gt;
* [[Alpha centrality]]&lt;br /&gt;
&lt;br /&gt;
* [[Core–periphery structure]]&lt;br /&gt;
&lt;br /&gt;
* [[Distance (graph theory)|Distance in graphs]]&lt;br /&gt;
&lt;br /&gt;
*阿尔法中心性&lt;br /&gt;
&lt;br /&gt;
*核心—外围结构&lt;br /&gt;
&lt;br /&gt;
*距离（图理论）图中的距离&lt;br /&gt;
&lt;br /&gt;
==Notes and references==&lt;br /&gt;
&lt;br /&gt;
{{Reflist}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Further reading==&lt;br /&gt;
拓展阅读&lt;br /&gt;
* Koschützki, D.; Lehmann, K. A.; Peeters, L.; Richter, S.; Tenfelde-Podehl, D. and Zlotowski, O. (2005) Centrality Indices. In Brandes, U. and Erlebach, T. (Eds.)  ''Network Analysis: Methodological Foundations'', pp.&amp;amp;nbsp;16–61, LNCS 3418, Springer-Verlag.&lt;br /&gt;
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[[Category:Graph theory]]&lt;br /&gt;
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Category:Graph theory&lt;br /&gt;
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分类: 图论&lt;br /&gt;
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[[Category:Graph algorithms]]&lt;br /&gt;
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Category:Graph algorithms&lt;br /&gt;
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分类: 图形算法&lt;br /&gt;
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[[Category:Algebraic graph theory]]&lt;br /&gt;
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Category:Algebraic graph theory&lt;br /&gt;
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分类: 代数图论&lt;br /&gt;
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[[Category:Networks]]&lt;br /&gt;
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Category:Networks&lt;br /&gt;
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分类: 网络&lt;br /&gt;
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[[Category:Network analysis]]&lt;br /&gt;
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Category:Network analysis&lt;br /&gt;
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分类: 网络分析&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Centrality]]. Its edit history can be viewed at [[网络中心性/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
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	<entry>
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		<title>网络中心性</title>
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		<updated>2020-12-10T07:13:21Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* 中心性指数的定义与特性Definition and characterization of centrality indices */&lt;/p&gt;
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&lt;div&gt;此词条暂由水流心不竞初译，未经审校，带来阅读不便，请见谅。&lt;br /&gt;
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{{for|the statistical concept|Central tendency}}&lt;br /&gt;
{{Network Science}}&lt;br /&gt;
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In [[graph theory]] and [[network theory|network analysis]], indicators of '''centrality''' identify the most important [[vertex (graph theory)|vertices]] within a graph. Applications include identifying the most influential person(s) in a [[social network]], key infrastructure nodes in the [[Internet]] or [[urban network]]s, and [[super-spreader]]s of disease. Centrality concepts were first developed in [[social network analysis]], and many of the terms used to measure centrality reflect their [[sociology|sociological]] origin.&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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In graph theory and network analysis, indicators of centrality identify the most important vertices within a graph. Applications include identifying the most influential person(s) in a social network, key infrastructure nodes in the Internet or urban networks, and super-spreaders of disease. Centrality concepts were first developed in , and many of the terms used to measure centrality reflect their sociological origin.&lt;br /&gt;
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They should not be confused with [[node influence metric]]s, which seek to quantify the influence of every node in the network.&lt;br /&gt;
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They should not be confused with node influence metrics, which seek to quantify the influence of every node in the network.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;图论 graph theory &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络分析 network analysis &amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性 centrality &amp;lt;/font&amp;gt;'''指标用于识别图中最重要的顶点。其应用包括在社会网络中识别出最有影响力的个人，在因特网或城市网络中识别出最为关键的基础设施节点，以及识别疾病的超级传播者。中心性的概念最初由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;社会网络分析 social network analysis&amp;lt;/font&amp;gt;'''所发展，因此许多用于衡量中心性的术语都反映出了它们的社会学出身。&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;中心性不应与节点影响度相混淆，后者意在量化网络中每个节点的影响。&lt;br /&gt;
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==中心性指数的定义与特性Definition and characterization of centrality indices==&lt;br /&gt;
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Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性指数 centrality indices&amp;lt;/font&amp;gt;'''旨在探寻如何描绘重要节点这一问题。这一问题的答案通常实值函数的形式给出，可根据函数值将图中各节点进行排序，进而确定最为重要的节点。&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
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The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
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“重要性”的含义十分广泛，因此导致了许多不同的中心性定义方式，我们可以将各种不同的定义方式划分为如下两类。&lt;br /&gt;
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&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important.&amp;lt;ref name=Borgatti2005/&amp;gt; &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt; Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important. &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&lt;br /&gt;
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“重要性”可以被设想为与网络中的某种流动或传输有关。&amp;lt;ref name=Borgatti2005/&amp;gt; “重要性”也可以被设想为与网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;内聚力 cohesiveness&amp;lt;/font&amp;gt;'''有关。这允许我们根据内聚力的不同测量方式对中心性予以分类。&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;这些方法将中心性划分于完全不同的类别中，也就是在一种类别中的中心性往往无法适用于其他类别。&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one ([[Centrality#Degree centrality|degree centrality]]) to infinite walks ([[Centrality#Eigenvector centrality|eigenvalue centrality]]).&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=&amp;quot;Benzi2013&amp;quot;&amp;gt;{{cite journal | last1=Benzi | first1=Michele | last2=Klymko| first2=Christine | year=2013 |title= A matrix analysis of different centrality measures |arxiv=1312.6722 | doi=10.1137/130950550 | volume=36 | issue=2 | journal=SIAM Journal on Matrix Analysis and Applications | pages=686–706}}&amp;lt;/ref&amp;gt; The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one (degree centrality) to infinite walks (eigenvalue centrality). The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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当根据内聚力方法对中心性进行分类时，很明显大多数中心性都将被划分于同一类别。起始于给定顶点的步数总和仅取决于步数的定义以及计数方式。这种分类方式的不足表现为它仅能较弱的描绘中心性特征，即按照一步步度（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;度中心性 degree centrality&amp;lt;/font&amp;gt;'''）到无穷步步长（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 eigenvalue centrality&amp;lt;/font&amp;gt;'''）的方式将中心性置于一种光谱状的分类中。&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=&amp;quot;Benzi2013&amp;quot;&amp;gt;{{cite journal | last1=Benzi | first1=Michele | last2=Klymko| first2=Christine | year=2013 |title= A matrix analysis of different centrality measures |arxiv=1312.6722 | doi=10.1137/130950550 | volume=36 | issue=2 | journal=SIAM Journal on Matrix Analysis and Applications | pages=686–706}}&amp;lt;/ref&amp;gt; 对于采用类似方式定义的各种中心性的观察也表明了这些指数之间的高阶相关性。&lt;br /&gt;
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===Characterization by network flows==&lt;br /&gt;
==网络流特征==&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at once.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at oe.&lt;br /&gt;
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一个网络可以被看成是对某种物体流动的路径描述。使基于流的类型和由中心性编码的路径类型（同时）得到表征。一个流可以基于传输，每个不可分割的项目从一个节点到另一个节点，就像一个包裹从配送站送到客户的房子。第二种情况是串行复制，在这种情况下，一个项从源节点被复制到达目标节点。例如通过流言传播信息，以私有方式传播信息，并在流程结束时通知源节点和目标节点。最后一种情况是并行复制，即同时将项目复制到多个链接，就像无线电广播一次性向多个听众提供相同的信息。&lt;br /&gt;
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Likewise, the type of path can be constrained to [[Distance (graph theory)|geodesics]] (shortest paths), [[Glossary of graph theory terms#path|paths]]  (no vertex is visited more than once), [[Glossary of graph theory terms#trail|trails]] (vertices can be visited multiple times, no edge is traversed more than once), or [[Glossary of graph theory terms#walk|walks]] (vertices and edges can be visited/traversed multiple times).&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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Likewise, the type of path can be constrained to geodesics (shortest paths), paths  (no vertex is visited more than once), trails (vertices can be visited multiple times, no edge is traversed more than once), or walks (vertices and edges can be visited/traversed multiple times).&lt;br /&gt;
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同样，路径类型可以被限定为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Distance &amp;lt;/font&amp;gt;'''(最短路径)、路径(对顶点的访问不超过一次)、小径(可以访问多次顶点，没有边被访问超过一次)或者步子(可以访问/遍历多次顶点和边)。&lt;br /&gt;
===Characterization by walk structure===&lt;br /&gt;
==行走结构特征==&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either ''radial'' or ''medial.'' Radial centralities count walks which start/end from the given vertex. The [[Centrality#Degree centrality|degree]] and [[Centrality#Eigenvector centrality|eigenvalue]] centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's [[Centrality#Betweenness centrality|betweenness]] centrality, the number of shortest paths which pass through the given vertex.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either radial or medial. Radial centralities count walks which start/end from the given vertex. The degree and eigenvalue centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's betweenness centrality, the number of shortest paths which pass through the given vertex.&lt;br /&gt;
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可以从中心性的构造方式推导出另一种分类方法。这又分成了两个类。中心点可以是放射状的，也可以是内侧的。从给定顶点开始/结束的径向中心点数。度和特征值中心是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 径向中心Radial centralities&amp;lt;/font&amp;gt;'''的例子，计算长度为一或无穷大的行走的个数。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中间中心性Medial centralities&amp;lt;/font&amp;gt;'''计算通过给定顶点的步数。典型的例子是 弗里曼的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality,&amp;lt;/font&amp;gt;'''，即穿过给定顶点的最短路径的数量。&lt;br /&gt;
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Likewise, the counting can capture either the ''volume'' or the ''length'' of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's [[Centrality#Closeness centrality|closeness]] centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example.&amp;lt;ref name=Borgatti2006/&amp;gt; Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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Likewise, the counting can capture either the volume or the length of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's closeness centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example. Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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同样地，计数可以抓住行走的体积或长度。体积是给定类型的行走的总数。上一段的三个例子就属于这一类。长度则给出从给定顶点到图中其余顶点的距离。弗里曼 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，即从一个给定顶点到所有其他顶点的测地距离，是最著名的例子。请注意，这种分类独立于步行计数的类型(即：步行，小道，路径，测地线)。&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&lt;br /&gt;
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博尔加蒂和埃弗雷特提出，这种类型学为如何最好地比较中心性度量提出了建议。在这个22分类中，放在同一盒子中的中心点足够相似，可以做出合理的选择; 人们可以合理地比较哪个对于给定的应用更好。然而，不同盒子中的度量方法是截然不同的。只有在预先确定哪个类别更适用的情况下，对相对适应性的评估才会发生，这使得比较变得毫无意义。&lt;br /&gt;
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===Radial-volume centralities exist on a spectrum===&lt;br /&gt;
==光谱上存在的径向体积中心==&lt;br /&gt;
The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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步行结构的特征表明，几乎所有广泛使用的中心性都是径向体积的衡量。这得出结论顶点的中心性是与之相关联的顶点中心性的函数。中心性根据如何定义关联而不同。&lt;br /&gt;
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Bonacich showed that if association is defined in terms of [[Glossary of graph theory terms#walk|walks]], then a family of centralities can be defined based on the length of walk considered.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;/&amp;gt; [[Centrality#Degree centrality|Degree centrality]] counts walks of length one, while [[Centrality#Eigenvector centrality|eigenvalue centrality]] counts walks of length infinity. Alternative definitions of association are also reasonable. [[Alpha centrality]] allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich showed that if association is defined in terms of walks, then a family of centralities can be defined based on the length of walk considered. Degree centrality counts walks of length one, while eigenvalue centrality counts walks of length infinity. Alternative definitions of association are also reasonable. Alpha centrality allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich 指出，如果联想是根据行走来定义的，那么可以根据考虑的行走长度来定义一个中心性家族。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''计算长度为1的行走，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征值中心性Eigenvalue centrality  &amp;lt;/font&amp;gt;'''计算长度为无穷大的行走。关联的其他定义也是合理的。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 阿尔法中心性Alpha centrality&amp;lt;/font&amp;gt;'''允许顶点有一个外部影响源。埃斯特拉达的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图中心性Subgraph centrality &amp;lt;/font&amp;gt;'''提出只计算封闭路径(三角形、正方形等)。).&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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这些测量方法的核心是这种现象：图中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵&amp;lt;/font&amp;gt;'''的幂给出了由该幂给出的散步长度的数目。同样，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 矩阵指数Matrix exponential&amp;lt;/font&amp;gt;'''也与给定长度的行走次数密切相关。邻接矩阵的初始转换允许对步行计数的类型进行不同的定义。无论采用哪种方法，顶点的中心性都可以表示为无穷和&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum _ { k = 0} ^ infty a _ { r } ^ { k } beta ^ k &amp;lt;/math &amp;gt; &lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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矩阵能量或者&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum { k = 0} ^ infty frac {(a _ r beta) ^ k }{ k！{/math &amp;gt; &lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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对于矩阵指数函数，其中&lt;br /&gt;
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* &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; is walk length,&lt;br /&gt;
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* &amp;lt;math&amp;gt;A_R&amp;lt;/math&amp;gt; is the transformed adjacency matrix, and&lt;br /&gt;
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* &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; is a discount parameter which ensures convergence of the sum.&lt;br /&gt;
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K为步长，A_R是邻接矩阵的转秩，贝达是保证收敛的折扣参数。&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. [[Alpha centrality]] replaces the adjacency matrix with its [[resolvent formalism|resolvent]]. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to [[Centrality#Degree centrality|degree centrality]]. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to [[Centrality#Eigenvector centrality|eigenvalue centrality]].&amp;lt;ref name=Benzi2013/&amp;gt;&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. Alpha centrality replaces the adjacency matrix with its resolvent. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to degree centrality. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to eigenvalue centrality.&lt;br /&gt;
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博纳奇的一系列措施并没有改变邻接矩阵。阿尔法集中性用它的解决方案替代了邻接矩阵。子图集中性用它的踪迹取代了邻接矩阵。一个令人吃惊的结论是，不管邻接矩阵最初的转变是什么，所有这些方法都有共同的限制行为。随着贝塔系数趋近于零，指数收敛到度中心性。随着贝塔系数接近其最大值，指数收敛到特征值的中心性。&lt;br /&gt;
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===Game-theoretic centrality===&lt;br /&gt;
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=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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上述大多数标准措施的共同特点是，它们通过只关注一个节点本身所扮演的角色来评估确定节点的重要性。然而, 在许多应用中，这种方法是不充分的，因为可能会发生协同作用&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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如果将节点的功能分组考虑。&lt;br /&gt;
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[[File:Game-theoretic centrality.png|Example of game-theoretic centrality]]&lt;br /&gt;
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Example of game-theoretic centrality&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''的例子&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in &amp;lt;ref&amp;gt;Michalak, Aadithya, Szczepański, Ravindran, &amp;amp; Jennings {{ArXiv|1402.0567}}&amp;lt;/ref&amp;gt; uses the [[Shapley value]]. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in  uses the Shapley value. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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例如，考虑阻止流行病的问题。看看上面的网络图像，我们应该给哪些节点接种疫苗？基于前面描述的措施，我们希望识别在疾病传播中最重要的节点。仅仅基于中心的方法，即关注节点的个别特性，可能不是一个好主意。红色方块中的节点，单独不能阻止疾病的传播，但把它们作为一个群体来考虑，我们清楚地看到，如果疾病在节点 &amp;lt; math &amp;gt; v _ 1 &amp;lt;/math &amp;gt; 、 &amp;lt; math &amp;gt; v _ 4 &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; v _ 5 &amp;lt;/math &amp;gt; 中开始，它们就能阻止疾病的传播。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''试图利用博弈论中的工具来研究所描述的问题和机会。本文提出的方法使用了 Shapley 值。由于 Shapley 值计算的时间复杂性，这一领域的大部分工作都集中在实现新的算法和方法，这些算法和方法依赖于网络的特殊拓扑结构或问题的特殊性质。这种方法可以将时间复杂度从指数级降低到多项式级。&lt;br /&gt;
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Similarly, the solution concept [[authority distribution]] (&amp;lt;ref&amp;gt;{{cite journal |last=Hu |first=Xingwei |first2=Lloyd |last2=Shapley |title=On Authority Distributions in Organizations |journal=Games and Economic Behavior |volume=45 |pages=132–170 |year=2003 | doi = 10.1016/s0899-8256(03)00130-1 }}&amp;lt;/ref&amp;gt;) applies the [[Shapley-Shubik power index]], rather than the [[Shapley value]], to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020)&amp;lt;ref&amp;gt;{{cite journal|last=Hu|first=Xingwei|year=2020|volume=7|title=Sorting big data by revealed preference with application to college ranking |journal=Journal of Big Data|doi=10.1186/s40537-020-00300-1|doi-access=free}}&amp;lt;/ref&amp;gt;, such as ranking U.S. colleges.&lt;br /&gt;
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Similarly, the solution concept authority distribution () applies the Shapley-Shubik power index, rather than the Shapley value, to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020), such as ranking U.S. colleges.&lt;br /&gt;
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同样，'''&amp;lt;font color=&amp;quot;#CD32CD&amp;quot;&amp;gt; 加权分布概念的解()The solution concept authority distribution () &amp;lt;/font&amp;gt;'''采用 Shapley-Shubik 幂指数，而不是 Shapley 值来衡量双方之间的直接影响。这种分布确实是一种产生'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征向量中心性Engenvector centrality&amp;lt;/font&amp;gt;'''的类型。它用于对 Hu (2020)中的大数据对象进行排序，比如美国大学排名。&lt;br /&gt;
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== Important limitations ==&lt;br /&gt;
==重要限制==&lt;br /&gt;
Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the [[Krackhardt kite graph]], for which three different notions of centrality give three different choices of the most central vertex.&amp;lt;ref&amp;gt;{{cite journal|title=Assessing the Political Landscape: Structure, Cognition, and Power in Organizations|first=David|last=Krackhardt|authorlink=David Krackhardt|journal=Administrative Science Quarterly|volume=35|issue=2|date=June 1990|pages=342–369|doi=10.2307/2393394|jstor=2393394}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the Krackhardt kite graph, for which three different notions of centrality give three different choices of the most central vertex.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中心性Centrality&amp;lt;/font&amp;gt;'''指标有两个重要的局限性，一个显而易见，另一个则不易察觉。显而易见的局限性是，对于一个应用最优的中心性对于另一个应用常常是次优的。事实上，如果不是这样，我们就不需要这么多不同的中心性。克拉克哈特风筝图为这一现象提供了一个例证，对于这个图，三个不同的中心性概念给出了三个最中心顶点的不同选择。&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices.&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=Borgatti2005/&amp;gt; This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  [[node influence metric]]s to address this problem.&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices. This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  node influence metrics to address this problem.&lt;br /&gt;
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更不易察觉的限制是通常会错误地认为顶点中心性表示顶点的相对重要性。中心性指数被明确地设计来产生一个指出最重要顶点的排名。在刚才提到的限制下，他们做得很好。它们通常不用来测量节点的影响力。最近，网络物理学家开始开发'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;节点影响度量Node influence metrics &amp;lt;/font&amp;gt;'''来解决这个问题。&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying [[Centrality#Freeman centralization|Freeman centralization]] to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt; This approach, however, is seldom seen in practice.{{citation needed|reason=I've come across quite some theoretical studies that indicate otherwise. My suggestion is to remove this sentence, if reasonable citation is not provided.|date=September 2015}}&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying Freeman centralization to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores. This approach, however, is seldom seen in practice.&lt;br /&gt;
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错误有两方面。首先，一个排名只根据顶点的重要性排序，它并不对节点重要性的不同水平进行量化区分。这可以通过将 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;'''应用到中心性度量来缓解，这种度量可以根据节点的不同中心性得分来判断节点的重要性。此外， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;''使人们能够通过比较几个网络的最高中心性得分来比较它们。然而，这种方法在实践中很少见到。&lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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其次，用以(正确地)识别给定网络/应用中最重要顶点的特征并不一定可推广到其余顶点。&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot; /&amp;gt;&amp;lt;ref name=&amp;quot;daSilva2012&amp;quot;&amp;gt;{{cite journal | last1=da Silva|first1=Renato |last2=Viana|first2=Matheus|last3=da F. Costa |first3=Luciano| title=Predicting epidemic outbreak from individual features of the spreaders| journal=J. Stat. Mech.: Theory Exp. | year=2012|volume=2012|pages=P07005|number=7 | doi=10.1088/1742-5468/2012/07/p07005|arxiv=1202.0024|bibcode=2012JSMTE..07..005A}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Bauer2012&amp;quot;&amp;gt;{{cite journal | last1=Bauer|first1=Frank | last2=Lizier|first2=Joseph|title=Identifying influential spreaders and efficiently estimating infection numbers in epidemic models: A walk counting approach| journal=Europhys Lett | year=2012| volume=99| pages=68007|number=6 | doi=10.1209/0295-5075/99/68007|arxiv=1203.0502|bibcode=2012EL.....9968007B}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Sikic2013&amp;quot;&amp;gt;{{ cite journal| last1= Sikic| first1=Mile|last2=Lancic|first2=Alen|last3=Antulov-Fantulin|first3=Nino|last4=Stefanic|first4=Hrvoje| title = Epidemic centrality -- is there an underestimated epidemic impact of network peripheral nodes? |journal = The European Physical Journal B |volume=86 |number=10 |pages=1–13 |year=2013 | doi=10.1140/epjb/e2013-31025-5|arxiv=1110.2558 | bibcode=2013EPJB...86..440S}}&amp;lt;/ref&amp;gt; This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&amp;lt;ref name=&amp;quot;Ghoshal2011&amp;quot;&amp;gt;{{cite journal | last1=Ghoshal | first1= G. | last2= Barabsi |first2= A L | title = Ranking stability and super-stable nodes in complex networks. | journal = Nat Commun | volume =2 | page = 394| year= 2011 | doi=10.1038/ncomms1396 | pmid= 21772265 | bibcode=2011NatCo...2..394G | doi-access= free }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless. This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&lt;br /&gt;
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对于大多数其他网络节点，排名可能是没有意义的。这就解释了为什么，例如，只有谷歌图片搜索的前几个结果以合理的顺序出现。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页排名Pagerank&amp;lt;/font&amp;gt;'''是一个非常不稳定的度量，显示了在跳转参数小的调整之后频繁的秩逆转。&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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虽然中心性指数未能推广到网络的其他部分，乍看起来似乎是违反直觉的，但它直接遵循上述定义。&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot;&amp;gt;{{cite journal |last1= Lawyer |first1= Glenn |year= 2015 |title= Understanding the spreading power of all nodes in a network: a continuous-time perspective |journal=Sci Rep |volume=5|pages=8665|doi=10.1038/srep08665 |pmid=25727453 |pmc=4345333|arxiv=1405.6707|bibcode=2015NatSR...5E8665L}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&lt;br /&gt;
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复杂网络具有异构的拓扑结构。由于最佳度量取决于最重要顶点的网络结构，对于这些顶点最优的度量对于网络的其余部分是次优的。&lt;br /&gt;
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==Degree centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Degree (graph theory)}} &lt;br /&gt;
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&lt;br /&gt;
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[[File:6 centrality measures.png|thumb|right|300px|Examples of A) [[Betweenness centrality]], B) [[Closeness centrality]], C) [[Eigenvector centrality]], D) [[Degree centrality]], E) [[Centrality#Harmonic centrality|Harmonic centrality]] and F) [[Katz centrality]] of the same graph.]]&lt;br /&gt;
&lt;br /&gt;
Examples of A) [[Betweenness centrality, B) Closeness centrality, C) Eigenvector centrality, D) Degree centrality, E) Harmonic centrality and F) Katz centrality of the same graph.]]&lt;br /&gt;
&lt;br /&gt;
实例 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; a)[中介中心性A) [[Betweenness centrality,b)紧密中心性，B) Closeness centrality, c)特征向量中心性，C) Eigenvector centrality, d)度中心性，D) Degree centrality, e)调和中心性，E) Harmonic centrality andf) 卡兹Katz 中心性]F) Katz centrality .]]&amp;lt;/font&amp;gt;'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Historically first and conceptually simplest is '''degree centrality''', which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely [[indegree]] and [[outdegree]]. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
&lt;br /&gt;
Historically first and conceptually simplest is degree centrality, which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely indegree and outdegree. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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历史上最简单的概念是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''，它定义为一个节点上发生的链接数量(即一个节点拥有的关系数量)。度可以根据节点捕获流经网络的任何东西(例如病毒或某些信息)的直接风险来解释。在有向网络的情况下(其中联系有方向) ，我们通常定义两个独立的度量，即 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度 Outdegree&amp;lt;/font&amp;gt;'''。因此，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度indegree&amp;lt;/font&amp;gt;'''是指向该节点的关系数，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度outdegree&amp;lt;/font&amp;gt;'''是指该节点指向其他节点的关系数。当关系与一些积极的方面如友谊或合作有关时， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''通常被解释为一种形式的受欢迎，而 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度Indegree&amp;lt;/font&amp;gt;'''则被解释为合群。&lt;br /&gt;
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The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
&lt;br /&gt;
The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
&lt;br /&gt;
对于给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边，度的中心性定义为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Calculating degree centrality for all the nodes in a graph takes [[big theta|&amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt;]] in a [[dense matrix|dense]] [[adjacency matrix]] representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a [[sparse matrix]] representation.&lt;br /&gt;
&lt;br /&gt;
Calculating degree centrality for all the nodes in a graph takes &amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt; in a dense adjacency matrix representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a sparse matrix representation.&lt;br /&gt;
&lt;br /&gt;
计算一个图中所有节点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''需要在图的稠密'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵Adjacency matrix &amp;lt;/font&amp;gt;'''表示中使用 Theta (v ^ 2) &amp;lt;/math &amp;gt; ，而在稀疏矩阵表示中使用 Theta (e) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of ''graph centralization''.&amp;lt;ref&amp;gt;Freeman, Linton C. &amp;quot;Centrality in social networks conceptual clarification.&amp;quot; Social networks 1.3 (1979): 215–239.&amp;lt;/ref&amp;gt; Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
&lt;br /&gt;
The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of graph centralization. Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
&lt;br /&gt;
节点级中心性的定义可以扩展到整个图，在这种情况下，我们指的是图的集中性。设 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 为 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''最高的节点。让 &amp;lt; math &amp;gt; x: = (y，z) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; | y | &amp;lt;/math &amp;gt; 节点连接图，最大化下列数量(&amp;lt; math &amp;gt; y * &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 中度最高的节点) :&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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:&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h = sum ^ { | y | }{ j = 1}[ c _ d (y *)-c _ d (y _ j)] &amp;lt;/math &amp;gt; &lt;br /&gt;
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Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
&lt;br /&gt;
Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
&lt;br /&gt;
相应地，图形 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''如下:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ h } &amp;lt;/math &amp;gt; &lt;br /&gt;
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The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a [[star graph]]), and in this case&lt;br /&gt;
&lt;br /&gt;
The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a star graph), and in this case&lt;br /&gt;
&lt;br /&gt;
当图形 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 包含一个所有其他节点都连接的中心节点(一个星形图)时，&amp;lt; math &amp;gt; h &amp;lt;/math &amp;gt; 的值最大化，在这种情况下&lt;br /&gt;
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:&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
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(n-1)-1) = n ^ 2-3n + 2&lt;br /&gt;
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So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
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So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
所以，对于任意的图 &amp;lt; math &amp;gt; g: = (v，e) ，&amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ | v | ^ 2-3 | v | + 2} &amp;lt;/math &amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Closeness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Closeness centrality}}In a [[Connected component (graph theory)|connected]] [[Graph (discrete mathematics)|graph]], the [[Normalization (statistics)|normalized]] '''closeness centrality''' (or '''closeness''') of a node is the average length of the [[Shortest path problem|shortest path]] between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
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In a connected graph, the normalized closeness centrality (or closeness) of a node is the average length of the shortest path between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
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在连通图中，节点的标准'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''(或贴近性)是节点与图中所有其他节点之间最短路径的平均长度。因此，一个节点越是中心，它就越接近所有其他节点。&lt;br /&gt;
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Closeness was defined by [[Alex Bavelas]] (1950) as the [[Multiplicative inverse|reciprocal]] of the '''farness''',&amp;lt;ref&amp;gt;Alex Bavelas. Communication patterns in task-oriented groups. ''J. Acoust. Soc. Am'', '''22'''(6):725–730, 1950.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;{{cite journal|year=1966|title=The centrality index of a graph|url=|journal=Psychometrika|volume=31|issue=4|pages=581–603|doi=10.1007/bf02289527|pmid=5232444|hdl=10338.dmlcz/101401|last1=Sabidussi|first1=G|hdl-access=free}}&amp;lt;/ref&amp;gt; that is:&lt;br /&gt;
&lt;br /&gt;
Closeness was defined by Alex Bavelas (1950) as the reciprocal of the farness, that is:&lt;br /&gt;
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亚历克斯 · 巴维拉斯(1950)将亲密度定义为相对于距离的倒数，即:&lt;br /&gt;
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&lt;br /&gt;
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: &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
C (x) = frac {1}{ sum _ y d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the [[Distance (graph theory)|distance]] between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the distance between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; d (y，x) &amp;lt;/math &amp;gt; 是顶点 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; 之间的距离。然而，当谈到'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''时，人们通常会提到它的标准化形式，一般是以前的公式乘以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; ，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。这种调整允许比较不同大小图形的节点。&lt;br /&gt;
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Taking distances ''from'' or ''to'' all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in [[directed graph]]s (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
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Taking distances from or to all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in directed graphs (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
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从所有其他节点或到所有其他节点的距离在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 无向图Undirected graphs&amp;lt;/font&amp;gt;'''中是不相关的，但是在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 有向图Directed graphs&amp;lt;/font&amp;gt;'''中可能产生完全不同的结果(例如:一个网站可以从传出链接获得高的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，而从传入链接获得低的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''）。&lt;br /&gt;
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===Harmonic centrality===&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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In a (not necessarily connected) graph, the '''harmonic centrality''' reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the harmonic centrality reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
在一个(不一定是连通的)图中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''反转了'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''定义中的和互反运算:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h (x) = sum { y neq x } frac {1}{ d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; 1/d (y，x) = 0 &amp;lt;/math &amp;gt; if there is no path from &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; to &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 。调和中心性可以通过除以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; 来标准化，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。&lt;br /&gt;
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Harmonic centrality was proposed by [[Massimo Marchiori|Marchiori]] and [[Vito Latora|Latora]] (2000)&amp;lt;ref name=&amp;quot;marchiorilatora2000&amp;quot;&amp;gt;{{citation| journal = Physica A: Statistical Mechanics and Its Applications  | last1 = Marchiori | first1 = Massimo | last2 = Latora | first2 = Vito | year = 2000 | volume = 285 | issue = 3–4 | pages = 539–546 | title = Harmony in the small-world | doi=10.1016/s0378-4371(00)00311-3| arxiv = cond-mat/0008357 | bibcode = 2000PhyA..285..539M }}&amp;lt;/ref&amp;gt; and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot;&amp;lt;ref&amp;gt;{{cite journal|first1=Anthony|last1=Dekker|title=Conceptual Distance in Social Network Analysis|journal=Journal of Social Structure|volume=6|issue=3|year=2005|url=http://www.cmu.edu/joss/content/articles/volume6/dekker/index.html}}&amp;lt;/ref&amp;gt; and by Rochat (2009).&amp;lt;ref&amp;gt;{{cite conference  | author = Yannick Rochat  | title = Closeness centrality extended to unconnected graphs: The harmonic centrality index | conference = Applications of Social Network Analysis, ASNA 2009 | url = http://infoscience.epfl.ch/record/200525/files/%5bEN%5dASNA09.pdf }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Harmonic centrality was proposed by Marchiori and Latora (2000) and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot; and by Rochat (2009).&lt;br /&gt;
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调和中心性是由 Marchiori 和 Latora (2000)提出的，然后是 Dekker (2005)独立提出的，使用的名称是“有价值的中心性” ，Rochat (2009)。&lt;br /&gt;
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==Betweenness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Betweenness centrality}}&lt;br /&gt;
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[[File:Graph betweenness.svg|240px|right|thumb|Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.]]&lt;br /&gt;
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Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.&lt;br /&gt;
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色调(从红色 = 0到蓝色 = max)表示节点之间的距离。&lt;br /&gt;
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'''Betweenness''' is a centrality measure of a [[vertex (graph theory)|vertex]] within a [[Graph (discrete mathematics)|graph]] (there is also [[edge (graph theory)|edge]] betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by [[Linton Freeman]]&amp;lt;ref name=&amp;quot;freeman1977&amp;quot;&amp;gt;{{cite journal |last1 = Freeman |first1 = Linton | year=1977| title = A set of measures of centrality based upon betweenness | journal = Sociometry| volume=40|issue = 1 | pages=35–41 | doi=10.2307/3033543|jstor = 3033543 }}&amp;lt;/ref&amp;gt; In his conception, vertices that have a high probability to occur on a randomly chosen [[shortest path problem|shortest path]] between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
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Betweenness is a centrality measure of a vertex within a graph (there is also edge betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by Linton Freeman In his conception, vertices that have a high probability to occur on a randomly chosen shortest path between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
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中介性是图中顶点的中心性度量(也有边中介性，这里没有讨论)。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''量化了一个节点沿着其他两个节点之间的最短路径充当桥梁的次数。在林顿 · 弗里曼的概念中，在两个随机选择的顶点之间随机选择的最短路径上出现概率高的顶点具有很高的中介性。&lt;br /&gt;
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The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
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The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
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在一个图 &amp;lt; math &amp;gt; g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的顶点之间的距离计算如下:&lt;br /&gt;
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# For each pair of vertices (''s'',''t''), compute the [[Shortest path problem|shortest paths]] between them.&lt;br /&gt;
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 For each pair of vertices (s,t), compute the shortest paths between them.&lt;br /&gt;
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对于每一对顶点(s，t) ，计算它们之间的最短路径。&lt;br /&gt;
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# For each pair of vertices (''s'',''t''), determine the fraction of shortest paths that pass through the vertex in question (here, vertex ''v'').&lt;br /&gt;
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 For each pair of vertices (s,t), determine the fraction of shortest paths that pass through the vertex in question (here, vertex v).&lt;br /&gt;
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对于每对顶点(s，t) ，确定通过该顶点(这里是顶点 v)的最短路径的分数。&lt;br /&gt;
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# Sum this fraction over all pairs of vertices (''s'',''t'').&lt;br /&gt;
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 Sum this fraction over all pairs of vertices (s,t).&lt;br /&gt;
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对所有顶点对(s，t)求这个分数的和。&lt;br /&gt;
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More compactly the betweenness can be represented as:&amp;lt;ref name=&amp;quot;brandes&amp;quot;&amp;gt;{{cite journal |last1 = Brandes |first1 = Ulrik | year=2001 |title = A faster algorithm for betweenness centrality  | journal = Journal of Mathematical Sociology| volume=25|issue = 2 | pages=163–177| url = http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.11.2024 | accessdate = October 11, 2011| format = PDF | doi=10.1080/0022250x.2001.9990249|citeseerx = 10.1.1.11.2024 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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More compactly the betweenness can be represented as:&lt;br /&gt;
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更确切地说，两者之间的关系可以表示为:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
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{ math &amp;gt; c _ b (v) = sum _ { s neq v neq t in v } frac { sigma _ st }(v)}{ sigma _ st } &amp;lt;/math &amp;gt; &lt;br /&gt;
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&lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including ''v'', which for [[Digraph (mathematics)|directed graphs]] is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected [[Star (graph theory)|star graph]], the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including v, which for directed graphs is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected star graph, the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; sigma { st } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { st }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径数。有向图是 &amp;lt; math &amp;gt; (n-1)(n-2) &amp;lt;/math &amp;gt; ，无向图是 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; 。例如，在一个无向星图中，中心顶点(包含在每个可能的最短路径中)的中介性为 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; (1，如果标准化) ，而叶子(包含在没有最短路径中)的中介性为0。&lt;br /&gt;
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From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires [[Big O notation|&amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt;]] time with the [[Floyd–Warshall algorithm]]. However, on sparse graphs, [[Johnson's algorithm]] may be more efficient, taking [[Big O notation|&amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt;]] time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm&amp;lt;ref name=brandes/&amp;gt; which takes [[Big O notation|&amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt;]] time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&amp;lt;ref name=&amp;quot;brandes&amp;quot; /&amp;gt;&lt;br /&gt;
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From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires &amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt; time with the Floyd–Warshall algorithm. However, on sparse graphs, Johnson's algorithm may be more efficient, taking &amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt; time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm which takes &amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt; time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&lt;br /&gt;
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从计算的角度来看，图中所有顶点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介和紧密中心性Betweenness and Closeness centralities&amp;lt;/font&amp;gt;'''都涉及到计算图中所有顶点对之间的最短路径，这就需要用 Floyd-Warshall 算法计算时间。然而，对于稀疏图，约翰逊算法的效率可能更高，采用 &amp;lt; math &amp;gt; o (v ^ 2 log v + v e) &amp;lt;/math &amp;gt; 时间。在不加权图的情况下，可以用 Brandes 的算法进行计算，该算法需要 &amp;lt; math &amp;gt; o (v e) &amp;lt;/math &amp;gt; 时间。一般情况下，这些算法假定图是无向的，并且连通图中允许有圈和多条边。当专门处理网络图时，图通常没有环或多条边来维持简单的关系(其中的边表示两个人或顶点之间的联系)。在这种情况下，使用 Brandes 的算法将最终的中心性分数除以2来计算每条被重复计算的最短路径。&lt;br /&gt;
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==Eigenvector centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Eigenvector centrality}}&lt;br /&gt;
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'''Eigenvector centrality''' (also called '''eigencentrality''') is a measure of the influence of a [[node (networking)|node]] in a [[network (mathematics)|network]]. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&amp;lt;ref&amp;gt;{{cite journal|title = The mathematics of networks|url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf|author = M. E. J. Newman|accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;/&amp;gt; [[Google]]'s [[PageRank]] and the [[Katz centrality]] are variants of the eigenvector centrality.&amp;lt;ref name=&amp;quot;ams&amp;quot;&amp;gt;{{Cite web | url=http://www.ams.org/samplings/feature-column/fcarc-pagerank | title=American Mathematical Society}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Eigenvector centrality (also called eigencentrality) is a measure of the influence of a node in a network. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''(也称为特征中心性)是衡量网络中节点影响的一个指标。它将相对得分分配给网络中的所有节点，这是基于这样一个概念: 与得分较高的节点相比，与得分较低的节点相同的连接对所涉及的节点的得分贡献更大。&lt;br /&gt;
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=== Using the adjacency matrix to find eigenvector centrality ==&lt;br /&gt;
==使用'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''发现'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the [[adjacency matrix]], i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
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For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the adjacency matrix, i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
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对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 让 &amp;lt; math &amp;gt; a = (a { v，t }) &amp;lt;/math &amp;gt; 成为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''，即。如果顶点 &amp;lt; math &amp;gt; &amp;gt; v &amp;lt;/math &amp;gt; 与 math &amp;gt; t &amp;lt;/math &amp;gt; 相连，而 &amp;lt; math &amp;gt; a { v，t } = 0 &amp;lt;/math &amp;gt; 否则。顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分可以定义为:&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
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在 m (v)} x _ t = frac {1}{ lambda } sum { t in g } a { v，t } x _ t &amp;lt;/math &amp;gt; &lt;br /&gt;
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where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the [[eigenvector]] equation&lt;br /&gt;
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where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the eigenvector equation&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; m (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 和 &amp;lt; math &amp;gt; &amp;gt; lambda &amp;lt;/math &amp;gt; 的邻居集合。通过一个小的重新排列，这可以被重写成向量符号，作为特征向量方程&lt;br /&gt;
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:&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
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[ math &amp;gt; mathbf { Ax } = { lambda } mathbf { x } &amp;lt;/math &amp;gt; &lt;br /&gt;
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In general, there will be many different [[eigenvalue]]s &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the [[Perron–Frobenius theorem]]. This greatest eigenvalue results in the desired centrality measure.&amp;lt;ref&amp;gt;{{cite journal  | author = M. E. J. Newman  | title = The mathematics of networks  | url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf  | accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt; The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices ''n''. [[Power iteration]] is one of many [[eigenvalue algorithm]]s that may be used to find this dominant eigenvector.&amp;lt;ref name=&amp;quot;ams&amp;quot; /&amp;gt; Furthermore, this can be generalized so that the entries in ''A'' can be real numbers representing connection strengths, as in a [[stochastic matrix]].&lt;br /&gt;
&lt;br /&gt;
In general, there will be many different eigenvalues &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the Perron–Frobenius theorem. This greatest eigenvalue results in the desired centrality measure. The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices n. Power iteration is one of many eigenvalue algorithms that may be used to find this dominant eigenvector. Furthermore, this can be generalized so that the entries in A can be real numbers representing connection strengths, as in a stochastic matrix.&lt;br /&gt;
&lt;br /&gt;
一般情况下，存在许多不同的特征值，对于这些特征值存在一个非零特征向量解。由于邻接矩阵中的条目是非负的，所以由 Perron-弗罗贝尼乌斯定理得出，它有一个实的和正的唯一最大特征值。由这个最大的特征值得出期望的中心性度量。相关特征向量的 &amp;lt; math &amp;gt; v ^ { th } &amp;lt;/math &amp;gt; 分量给出了网络中顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分。特征向量只定义了一个公共因子，所以只有顶点中心的比例是明确定义的。要定义一个绝对分数，必须对特征向量进行标准化，例如，使所有顶点的和为1或顶点的总数n。此外，这可以通用，使得 a 中的条目可以是表示连接强度的真实数字，就像'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 随机矩阵Stochastic matrix&amp;lt;/font&amp;gt;'''中一样。&lt;br /&gt;
&lt;br /&gt;
==Katz centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Katz centrality}}&lt;br /&gt;
&lt;br /&gt;
'''Katz centrality'''&amp;lt;ref&amp;gt;Katz, L. 1953. A New Status Index Derived from Sociometric Index. Psychometrika, 39–43.&amp;lt;/ref&amp;gt; is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
Katz centrality is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''是度中心性的推广。度中心性度量的是直接邻居的数量，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''度量的是通过一条路径可以连接的所有节点的数量，而远处节点的贡献会受到'''&amp;lt;font color=&amp;quot;#32CD32&amp;quot;&amp;gt; '削弱（惩罚？）Penalized&amp;lt;/font&amp;gt;''。在数学上，它被定义为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[数学][数学]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; (0,1) &amp;lt;/math &amp;gt; 中的衰减因子。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
&lt;br /&gt;
Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''可以看作是特征向量中心性的变体。Katz 中心性的另一种形式是&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
(x _ j + 1) &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
与特征向量中心性的表达式相比，&amp;lt; math &amp;gt; x _ j &amp;lt;/math &amp;gt; 被 &amp;lt; math &amp;gt; x _ j + 1所代替&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
It is shown that&amp;lt;ref&amp;gt;{{cite journal | last1 = Bonacich | first1 = P | year = 1991 | title = Simultaneous group and individual centralities | url = | journal = Social Networks | volume = 13 | issue = 2| pages = 155–168 | doi=10.1016/0378-8733(91)90018-o}}&amp;lt;/ref&amp;gt; the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
&lt;br /&gt;
It is shown that the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
&lt;br /&gt;
结果表明，主特征向量(与 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; ，邻接矩阵的最大特征值相关)是 Katz 中心性的极限，因为 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 接近 &amp;lt; math &amp;gt; tfrac {1}{ lambda } &amp;lt;/math &amp;gt; 。&lt;br /&gt;
&lt;br /&gt;
== PageRank centrality ==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页分布中心性PageRank&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
{{main|PageRank}}'''[[PageRank]]''' satisfies the following equation&lt;br /&gt;
&lt;br /&gt;
PageRank satisfies the following equation&lt;br /&gt;
&lt;br /&gt;
PageRank满足下面的等式&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1-alpha { n } ，&amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
其中&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[ math &amp;gt; l (j) = sum { i } a { ji } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&amp;lt;ref&amp;gt;[http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf How does Google rank webpages?] {{webarchive | url= https://web.archive.org/web/20120131083328/http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf |date=January 31, 2012 }} 20Q: About Networked Life&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&lt;br /&gt;
&lt;br /&gt;
是节点 &amp;lt; math &amp;gt; j &amp;lt;/math &amp;gt; (或有向图中出站链接的数量)的邻居数量。与特征向量中心性和 Katz 中心性相比，尺度因子 &amp;lt; math &amp;gt; l (j) &amp;lt;/math &amp;gt; 是一个主要的区别。PageRank 和特征向量中心性的另一个区别是 PageRank 向量是一个左手特征向量(注意因子 &amp;lt; math &amp;gt; a _ { ji } &amp;lt;/math &amp;gt; 具有相反的索引)。&lt;br /&gt;
&lt;br /&gt;
==Percolation centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&amp;lt;ref name=&amp;quot;piraveenan2013&amp;quot;&amp;gt;{{cite journal |last1 = Piraveenan |first1 = M. |last2 = Prokopenko |first2 = M.|last3 = Hossain|first3 = L. |year=2013| title = Percolation Centrality: Quantifying Graph-Theoretic Impact of Nodes during Percolation in Networks | journal = PLOS One | volume=8 | issue=1 | doi=10.1371/journal.pone.0053095 | pages=e53095 | pmid=23349699 | pmc=3551907| bibcode=2013PLoSO...853095P }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&lt;br /&gt;
&lt;br /&gt;
在复杂网络中，存在大量的中心性度量来确定单个节点的“重要性”。然而，这些度量单纯从拓扑学的角度来量化节点的重要性，节点的值并不以任何方式依赖于节点的状态。不管网络动态如何，它都保持不变。即使对于加权的两者之间的度量也是如此。然而，一个节点可能很好地位于'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''或其他中心性度量的中心位置，但可能不是位于有过滤的网络的上下文中的中心位置。在许多情况下，复杂网络中都会出现“传染”现象。例如，病毒或细菌感染可以通过人们的社交网络传播，也就是所谓的接触网络。还可以在更高的抽象层次上考虑疾病的传播问题，设想通过公路、铁路或空中连接起来的城镇或人口中心网络。计算机病毒可以通过计算机网络传播。关于商业活动和交易的谣言或新闻也可以通过人们的社交网络传播。在所有这些情况下，一种“传染病”在一个复杂网络的链接上传播，随着它的传播，无论是可恢复的还是不可恢复的，都会改变节点的“状态”。例如，在流行病学方案中，随着感染扩散，个人从”易感”状态转变为”受感染”状态。在上面的例子中，随着传染的扩散，每个节点可以采取的状态可以是二进制的(例如接收/没有接收到一条新闻)、离散的(易感/受感染/康复) ，甚至是连续的(例如一个城镇中受感染的人的比例) 。这些情景的共同特点是，传染的扩散导致网络中节点状态的改变。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''（PC)就是基于这个思想而提出的，它特别地衡量了节点在协助网络渗滤方面的重要性。这项措施是由 piraveanan 等人提出的。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
'''Percolation centrality''' is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
&lt;br /&gt;
Percolation centrality is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''定义为在给定时间内一个给定节点的过滤路径的比例。“渗滤路径”是一对节点之间的最短路径，其中源节点被渗滤(例如，被感染)。目标节点可以是过滤的或非过滤的，或处于部分过滤状态。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; PC ^ t (v) = frac {1}{ N-2} sum { s neq v neq r } frac { sigma { sr }(v)}{ sigma { sr }} frac { x ^ t }{ sum {[{ x ^ t } i }}}]}}-{ x ^ t }{ v } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; σ { sr } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; r &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { sr }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径的总数。在时间 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 时，节点的过滤状态用 &amp;lt; math &amp;gt; { x ^ t } _ i &amp;lt;/math &amp;gt; 表示，两个特殊情况是当 &amp;lt; math &amp;gt; { x ^ t } _ i = 0 &amp;lt;/math &amp;gt; 表示在时间上是非过滤状态，而当 &amp;lt; math &amp;gt; &amp;lt; x ^ t &amp;lt;/math &amp;gt; i = 1 &amp;lt;/math &amp;gt; 表示在时间上是完全过滤状态。两者之间的值表示部分过滤状态(例如，在一个城镇网络中，这是该城镇感染者的百分比)。&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in [[Big O notation|&amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt;]] time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is [[Big O notation|&amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;]].&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in &amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt; time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is &amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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渗流路径的权重取决于分配给源节点的渗流水平，前提是源节点的渗流水平越高，源节点的路径就越重要。因此，位于源自高渗滤节点的最短路径上的节点可能对渗滤更为重要。PC 的定义也可以扩展到包括目标节点的权重。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''计算运行在 &amp;lt; math &amp;gt; o (NM) &amp;lt;/math &amp;gt; 时间，采用了 Brandes 快速算法的有效实现，如果计算需要考虑目标节点的权重，最坏情况下时间为 &amp;lt; math &amp;gt; o (n ^ 3) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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==Cross-clique centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 交叉团中心性Cross-clique centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
'''Cross-clique centrality''' of a single node in a complex graph determines the connectivity of a node to different [[clique (graph theory)|clique]]s. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in &amp;lt;ref name=&amp;quot;xssworms&amp;quot;&amp;gt;{{cite journal |last1 = Faghani|first1 = Mohamamd Reza| year=2013| title = A Study of XSS Worm Propagation and Detection Mechanisms in Online Social Networks | journal = IEEE Transactions on Information Forensics and Security|volume = 8|issue = 11|pages = 1815–1826|doi = 10.1109/TIFS.2013.2280884}}&amp;lt;/ref&amp;gt; but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
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Cross-clique centrality of a single node in a complex graph determines the connectivity of a node to different cliques. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in  but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
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复杂图中单个节点的跨团中心性决定了一个节点与不同团的连通性。具有高度跨团连通性的节点有利于信息或疾病在图中的传播。团是一种'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图Subgraphs&amp;lt;/font&amp;gt;'''，团中的每个节点都与团中的其他节点相连。对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边的交叉团连通性，定义为 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; x (v) &amp;lt;/math &amp;gt; 其中 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 所属的顶点团数。这个测度应用日久，但是在1998年由 Everett 和 Borgatti 首次提出，他们称之为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 派系重叠中心性Clique-overlap centrality&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Freeman centralization==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心度Freeman centralization&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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The '''centralization''' of any network is a measure of how central its most central node is in relation to how central all the other nodes are.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;&amp;gt;{{citation | journal = Social Networks | last1 = Freeman | first1 = Linton C. | year = 1979 | volume = 1 | issue = 3 | pages = 215–239 | title = centrality in social networks: Conceptual clarification | url = http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | doi = 10.1016/0378-8733(78)90021-7 | citeseerx = 10.1.1.227.9549 | access-date = 2014-07-31 | archive-url = https://web.archive.org/web/20160222033108/http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | archive-date = 2016-02-22 | url-status = dead }}&amp;lt;/ref&amp;gt; Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
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The centralization of any network is a measure of how central its most central node is in relation to how central all the other nodes are. Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
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任何网络的集中度都是衡量其最核心的节点相对于其他所有节点的集聚程度的标准。集中度的度量方法是: (a)计算网络中最中心的节点与所有其他节点之间的中心性差异之和; (b)将这个数量除以理论上相同规模的任何网络中这种差异之和的最大值。因此，每个中心性度量都可以有自己的集中性度量。正式定义，如果 &amp;lt; math &amp;gt; c _ x (p _ i) &amp;lt;/math &amp;gt; 是点 &amp;lt; math &amp;gt; i &amp;lt;/math &amp;gt; 的中心性度量，如果 &amp;lt; math &amp;gt; c _ x (p _ *) &amp;lt;/math &amp;gt; 是网络中最大的中心性度量，如果:&lt;br /&gt;
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:&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; max sum { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i) &amp;lt;/math &amp;gt; &lt;br /&gt;
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is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;&lt;br /&gt;
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is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&lt;br /&gt;
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对于任何具有相同节点数的图来说，点中心性的最大差异是:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; c _ x = frac { sum _ { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i)}{ max sum _ { i = 1 ^ { n } c _ x (p _ *)-c _ x (p _ i)} . &amp;lt;/math &amp;gt;&lt;br /&gt;
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== Dissimilarity based centrality measures ==&lt;br /&gt;
==基于相异性的中心性度量==&lt;br /&gt;
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[[File:Srep17095-f1.jpg|thumbnail|In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.]]&lt;br /&gt;
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In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.&lt;br /&gt;
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在图示的网络中，绿色节点和红色节点最不相似，因为它们之间不共享相邻节点。因此，绿色的节点比灰色的节点对中心性的贡献更大，因为红色的节点只能通过绿色访问蓝色的节点，而灰色的节点对于红色的节点是多余的，因为它可以直接访问每个灰色的节点，而不需要任何中介。&lt;br /&gt;
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In order to obtain better results in the ranking of the nodes of a given network,  in &amp;lt;ref&amp;gt;{{Cite journal|title = Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|journal = Scientific Reports|date = 2015-11-25|pmc = 4658528|pmid = 26603652|volume = 5|doi = 10.1038/srep17095|first = A. J.|last = Alvarez-Socorro|first2 = G. C.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz|pages=17095|bibcode = 2015NatSR...517095A}}&amp;lt;/ref&amp;gt; are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with [[eigenvector centrality]], calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
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In order to obtain better results in the ranking of the nodes of a given network,  in  are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with eigenvector centrality, calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
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为了在给定网络节点的排序中获得更好的结果，在复杂网络中使用了相异性度量(特定于分类和数据挖掘理论)来丰富中心性度量。特征向量中心性通过求解特征值问题来计算每个节点的中心性&lt;br /&gt;
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:&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
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数学，数学&lt;br /&gt;
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where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary [[Matrix similarity|dissimilarity]] matrix, defined through a dissimilitary measure, e.g., [[Jaccard index|Jaccard]] dissimilarity given by&lt;br /&gt;
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where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary dissimilarity matrix, defined through a dissimilitary measure, e.g., Jaccard dissimilarity given by&lt;br /&gt;
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这里 &amp;lt; math &amp;gt; w { ij } = a { ij } d { ij } &amp;lt;/math &amp;gt; (coordinate-to-coordinate product)和 &amp;lt; math &amp;gt; d { ij } &amp;lt;/math &amp;gt; 是一个任意的不相似矩阵，通过一个双重军事度量来定义，例如，Jaccard 由&lt;br /&gt;
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:&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
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1-dfrac { | v ^ { + }(i) cap v ^ { + }(j) | }{ | v ^ { + }(i) cup v ^ { + }(j) | } &amp;lt;/math &amp;gt; &lt;br /&gt;
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Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
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Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
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这种度量允许我们量化每个节点对给定节点中心性的拓扑贡献(这就是为什么我们称之为贡献中心性) ，对那些相异性较大的节点有更多的权重/相关性，因为这些节点允许给定的节点访问那些它们自己不能直接访问的节点。&lt;br /&gt;
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Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the [[Perron–Frobenius theorem]] to ensure that the above problem has a unique solution for ''λ'' = ''λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt;'' with '''c''' non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
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Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the Perron–Frobenius theorem to ensure that the above problem has a unique solution for λ = λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt; with c non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
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值得注意的是，&amp;lt; math &amp;gt; w &amp;lt;/math &amp;gt; 是非负的，因为 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; d &amp;lt;/math &amp;gt; 都是非负矩阵，所以我们可以使用 Perron 弗罗贝尼乌斯定理来确保上述问题对于 c 非负的 = &amp;lt; sub &amp;gt; max &amp;lt;/sub &amp;gt; 有唯一的解，这样我们就可以推断出网络中每个节点的中心性。因此，i-th 节点的中心性为&lt;br /&gt;
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:&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
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1{ n } sum { j = 1} ^ { n } w { ij } c { j } ，，，，，j = 1，cdots，n &amp;lt;/math &amp;gt; &lt;br /&gt;
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&lt;br /&gt;
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where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in &amp;lt;ref&amp;gt;{{Cite web|url = http://www.nature.com/article-assets/npg/srep/2015/151125/srep17095/extref/srep17095-s1.pdf|title = Supplementary Information for Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|date = |website = |publisher = Nature Publishing Group|last = Alvarez-Socorro|first = A.J.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz}}&amp;lt;/ref&amp;gt; obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in  obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是网络中的节点数。几个不同的措施和网络进行了测试，以获得在研究案例的改善的结果。&lt;br /&gt;
&lt;br /&gt;
==Extensions==&lt;br /&gt;
==扩展==&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality&amp;lt;ref&amp;gt;{{cite journal | last1 = Braha | first1 = D. | last2 = Bar-Yam | first2 = Y. | year = 2006 | title = From Centrality to Temporary Fame: Dynamic Centrality in Complex Networks | url = | journal = Complexity | volume = 12 | issue = 2| pages = 59–63 | doi=10.1002/cplx.20156| arxiv = physics/0611295 | bibcode = 2006Cmplx..12b..59B }}&amp;lt;/ref&amp;gt; in the context of time-dependent and temporal networks.&amp;lt;ref&amp;gt;{{cite journal | last1 = Hill | first1 = S.A. | last2 = Braha | first2 = D. | year = 2010 | title = Dynamic Model of Time-Dependent Complex Networks | url = | journal = Physical Review E | volume = 82 | issue = 4| page = 046105 | doi=10.1103/physreve.82.046105| pmid = 21230343 | arxiv = 0901.4407 | bibcode = 2010PhRvE..82d6105H }}&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Gross, T. and Sayama, H. (Eds.). 2009. ''Adaptive Networks: Theory, Models and Applications.'' Springer.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Holme, P. and Saramäki, J. 2013. ''Temporal Networks.'' Springer.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality in the context of time-dependent and temporal networks.&lt;br /&gt;
&lt;br /&gt;
经验和理论研究已经将静态网络中的中心性概念扩展到时间依赖网络和时间网络中的动态中心性。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&amp;lt;ref&amp;gt;{{cite journal | last1 = Opsahl | first1 = Tore | last2 = Agneessens | first2 = Filip | last3 = Skvoretz | first3 = John | title = Node centrality in weighted networks: Generalizing degree and shortest paths | doi = 10.1016/j.socnet.2010.03.006 | year = 2010 | pages = 245–251 | volume = 32 | journal = Social Networks | url = http://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | issue = 3 | access-date = 2010-04-23 | archive-url = https://web.archive.org/web/20180226080331/https://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | archive-date = 2018-02-26 | url-status = dead }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&lt;br /&gt;
&lt;br /&gt;
对加权网络的推广，见 Opsahl 等人。(2010).&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, '''group betweenness''' centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&amp;lt;ref name=&amp;quot;group1&amp;quot;&amp;gt;Everett, M. G. and Borgatti, S. P. (2005). Extending centrality. In P. J. Carrington, J. Scott and S. Wasserman (Eds.), ''Models and methods in social network analysis'' (pp. 57–76). New York: Cambridge University Press.&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;group2&amp;quot;&amp;gt;Puzis, R., Yagil, D., Elovici, Y., Braha, D. (2009).[http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf Collaborative attack on Internet users’ anonymity] {{Webarchive|url=https://web.archive.org/web/20131207133417/http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf |date=2013-12-07 }}, ''Internet Research'' '''19'''(1)&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, group betweenness centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&lt;br /&gt;
&lt;br /&gt;
中心性的概念也扩展到了群体层次。例如，组间的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''显示了连接穿过组的成对非组成员的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Geodesics &amp;lt;/font&amp;gt;'''的比例。&lt;br /&gt;
&lt;br /&gt;
==See also==&lt;br /&gt;
==又及==&lt;br /&gt;
* [[Alpha centrality]]&lt;br /&gt;
&lt;br /&gt;
* [[Core–periphery structure]]&lt;br /&gt;
&lt;br /&gt;
* [[Distance (graph theory)|Distance in graphs]]&lt;br /&gt;
&lt;br /&gt;
*阿尔法中心性&lt;br /&gt;
&lt;br /&gt;
*核心—外围结构&lt;br /&gt;
&lt;br /&gt;
*距离（图理论）图中的距离&lt;br /&gt;
&lt;br /&gt;
==Notes and references==&lt;br /&gt;
&lt;br /&gt;
{{Reflist}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Further reading==&lt;br /&gt;
拓展阅读&lt;br /&gt;
* Koschützki, D.; Lehmann, K. A.; Peeters, L.; Richter, S.; Tenfelde-Podehl, D. and Zlotowski, O. (2005) Centrality Indices. In Brandes, U. and Erlebach, T. (Eds.)  ''Network Analysis: Methodological Foundations'', pp.&amp;amp;nbsp;16–61, LNCS 3418, Springer-Verlag.&lt;br /&gt;
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[[Category:Graph theory]]&lt;br /&gt;
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Category:Graph theory&lt;br /&gt;
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分类: 图论&lt;br /&gt;
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[[Category:Graph algorithms]]&lt;br /&gt;
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Category:Graph algorithms&lt;br /&gt;
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分类: 图形算法&lt;br /&gt;
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[[Category:Algebraic graph theory]]&lt;br /&gt;
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Category:Algebraic graph theory&lt;br /&gt;
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分类: 代数图论&lt;br /&gt;
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[[Category:Networks]]&lt;br /&gt;
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Category:Networks&lt;br /&gt;
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分类: 网络&lt;br /&gt;
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[[Category:Network analysis]]&lt;br /&gt;
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Category:Network analysis&lt;br /&gt;
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分类: 网络分析&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Centrality]]. Its edit history can be viewed at [[网络中心性/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E7%BD%91%E7%BB%9C%E4%B8%AD%E5%BF%83%E6%80%A7&amp;diff=19878</id>
		<title>网络中心性</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E7%BD%91%E7%BB%9C%E4%B8%AD%E5%BF%83%E6%80%A7&amp;diff=19878"/>
		<updated>2020-12-10T07:12:04Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* 中心性指数的定义与特性Definition and characterization of centrality indices */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;此词条暂由水流心不竞初译，未经审校，带来阅读不便，请见谅。&lt;br /&gt;
&lt;br /&gt;
{{for|the statistical concept|Central tendency}}&lt;br /&gt;
{{Network Science}}&lt;br /&gt;
&lt;br /&gt;
In [[graph theory]] and [[network theory|network analysis]], indicators of '''centrality''' identify the most important [[vertex (graph theory)|vertices]] within a graph. Applications include identifying the most influential person(s) in a [[social network]], key infrastructure nodes in the [[Internet]] or [[urban network]]s, and [[super-spreader]]s of disease. Centrality concepts were first developed in [[social network analysis]], and many of the terms used to measure centrality reflect their [[sociology|sociological]] origin.&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
In graph theory and network analysis, indicators of centrality identify the most important vertices within a graph. Applications include identifying the most influential person(s) in a social network, key infrastructure nodes in the Internet or urban networks, and super-spreaders of disease. Centrality concepts were first developed in , and many of the terms used to measure centrality reflect their sociological origin.&lt;br /&gt;
&lt;br /&gt;
They should not be confused with [[node influence metric]]s, which seek to quantify the influence of every node in the network.&lt;br /&gt;
&lt;br /&gt;
They should not be confused with node influence metrics, which seek to quantify the influence of every node in the network.&lt;br /&gt;
&lt;br /&gt;
在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;图论 graph theory &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络分析 network analysis &amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性 centrality &amp;lt;/font&amp;gt;'''指标用于识别图中最重要的顶点。其应用包括在社会网络中识别出最有影响力的个人，在因特网或城市网络中识别出最为关键的基础设施节点，以及识别疾病的超级传播者。中心性的概念最初由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;社会网络分析 social network analysis&amp;lt;/font&amp;gt;'''所发展，因此许多用于衡量中心性的术语都反映出了它们的社会学出身。&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;中心性不应与节点影响度相混淆，后者意在量化网络中每个节点的影响。&lt;br /&gt;
&lt;br /&gt;
==中心性指数的定义与特性Definition and characterization of centrality indices==&lt;br /&gt;
&lt;br /&gt;
Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性指数 centrality indices&amp;lt;/font&amp;gt;'''旨在探寻如何描绘重要节点这一问题。这一问题的答案通常实值函数的形式给出，可根据函数值将图中各节点进行排序，进而确定最为重要的节点。&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
&lt;br /&gt;
The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
&lt;br /&gt;
“重要性”的含义十分广泛，因此导致了许多不同的中心性定义方式，我们可以将各种不同的定义方式划分为如下两类。&lt;br /&gt;
&lt;br /&gt;
&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important.&amp;lt;ref name=Borgatti2005/&amp;gt; &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt; Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important. &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&lt;br /&gt;
&lt;br /&gt;
“重要性”可以被设想为与网络中的某种流动或传输有关。&amp;lt;ref name=Borgatti2005/&amp;gt; “重要性”也可以被设想为与网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;内聚力 cohesiveness&amp;lt;/font&amp;gt;'''有关。这允许我们根据内聚力的不同测量方式对中心性予以分类。&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;这些方法将中心性划分于完全不同的类别中，也就是在一种类别中的中心性往往无法适用于其他类别。&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one ([[Centrality#Degree centrality|degree centrality]]) to infinite walks ([[Centrality#Eigenvector centrality|eigenvalue centrality]]).&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=&amp;quot;Benzi2013&amp;quot;&amp;gt;{{cite journal | last1=Benzi | first1=Michele | last2=Klymko| first2=Christine | year=2013 |title= A matrix analysis of different centrality measures |arxiv=1312.6722 | doi=10.1137/130950550 | volume=36 | issue=2 | journal=SIAM Journal on Matrix Analysis and Applications | pages=686–706}}&amp;lt;/ref&amp;gt; The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
&lt;br /&gt;
When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one (degree centrality) to infinite walks (eigenvalue centrality). The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
&lt;br /&gt;
当根据内聚力方法对中心性进行分类时，很明显大多数中心性都将被划分于同一类别。起始于给定顶点的步数总和仅取决于步数的定义以及计数方式。这种分类方式的不足表现为它仅能较弱的描绘中心性特征，即按照一步步度（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;度中心性 degree centrality&amp;lt;/font&amp;gt;'''）到无穷步步长（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 eigenvalue centrality&amp;lt;/font&amp;gt;'''）的方式将中心性置于一种光谱状的分类中。对于采用类似方式定义的各种中心性的观察也表明了这些指数之间的高阶相关性。&lt;br /&gt;
&lt;br /&gt;
===Characterization by network flows==&lt;br /&gt;
==网络流特征==&lt;br /&gt;
&lt;br /&gt;
A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at once.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at oe.&lt;br /&gt;
&lt;br /&gt;
一个网络可以被看成是对某种物体流动的路径描述。使基于流的类型和由中心性编码的路径类型（同时）得到表征。一个流可以基于传输，每个不可分割的项目从一个节点到另一个节点，就像一个包裹从配送站送到客户的房子。第二种情况是串行复制，在这种情况下，一个项从源节点被复制到达目标节点。例如通过流言传播信息，以私有方式传播信息，并在流程结束时通知源节点和目标节点。最后一种情况是并行复制，即同时将项目复制到多个链接，就像无线电广播一次性向多个听众提供相同的信息。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Likewise, the type of path can be constrained to [[Distance (graph theory)|geodesics]] (shortest paths), [[Glossary of graph theory terms#path|paths]]  (no vertex is visited more than once), [[Glossary of graph theory terms#trail|trails]] (vertices can be visited multiple times, no edge is traversed more than once), or [[Glossary of graph theory terms#walk|walks]] (vertices and edges can be visited/traversed multiple times).&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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Likewise, the type of path can be constrained to geodesics (shortest paths), paths  (no vertex is visited more than once), trails (vertices can be visited multiple times, no edge is traversed more than once), or walks (vertices and edges can be visited/traversed multiple times).&lt;br /&gt;
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同样，路径类型可以被限定为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Distance &amp;lt;/font&amp;gt;'''(最短路径)、路径(对顶点的访问不超过一次)、小径(可以访问多次顶点，没有边被访问超过一次)或者步子(可以访问/遍历多次顶点和边)。&lt;br /&gt;
===Characterization by walk structure===&lt;br /&gt;
==行走结构特征==&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either ''radial'' or ''medial.'' Radial centralities count walks which start/end from the given vertex. The [[Centrality#Degree centrality|degree]] and [[Centrality#Eigenvector centrality|eigenvalue]] centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's [[Centrality#Betweenness centrality|betweenness]] centrality, the number of shortest paths which pass through the given vertex.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either radial or medial. Radial centralities count walks which start/end from the given vertex. The degree and eigenvalue centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's betweenness centrality, the number of shortest paths which pass through the given vertex.&lt;br /&gt;
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可以从中心性的构造方式推导出另一种分类方法。这又分成了两个类。中心点可以是放射状的，也可以是内侧的。从给定顶点开始/结束的径向中心点数。度和特征值中心是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 径向中心Radial centralities&amp;lt;/font&amp;gt;'''的例子，计算长度为一或无穷大的行走的个数。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中间中心性Medial centralities&amp;lt;/font&amp;gt;'''计算通过给定顶点的步数。典型的例子是 弗里曼的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality,&amp;lt;/font&amp;gt;'''，即穿过给定顶点的最短路径的数量。&lt;br /&gt;
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Likewise, the counting can capture either the ''volume'' or the ''length'' of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's [[Centrality#Closeness centrality|closeness]] centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example.&amp;lt;ref name=Borgatti2006/&amp;gt; Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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Likewise, the counting can capture either the volume or the length of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's closeness centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example. Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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同样地，计数可以抓住行走的体积或长度。体积是给定类型的行走的总数。上一段的三个例子就属于这一类。长度则给出从给定顶点到图中其余顶点的距离。弗里曼 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，即从一个给定顶点到所有其他顶点的测地距离，是最著名的例子。请注意，这种分类独立于步行计数的类型(即：步行，小道，路径，测地线)。&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&lt;br /&gt;
&lt;br /&gt;
博尔加蒂和埃弗雷特提出，这种类型学为如何最好地比较中心性度量提出了建议。在这个22分类中，放在同一盒子中的中心点足够相似，可以做出合理的选择; 人们可以合理地比较哪个对于给定的应用更好。然而，不同盒子中的度量方法是截然不同的。只有在预先确定哪个类别更适用的情况下，对相对适应性的评估才会发生，这使得比较变得毫无意义。&lt;br /&gt;
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===Radial-volume centralities exist on a spectrum===&lt;br /&gt;
==光谱上存在的径向体积中心==&lt;br /&gt;
The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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步行结构的特征表明，几乎所有广泛使用的中心性都是径向体积的衡量。这得出结论顶点的中心性是与之相关联的顶点中心性的函数。中心性根据如何定义关联而不同。&lt;br /&gt;
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Bonacich showed that if association is defined in terms of [[Glossary of graph theory terms#walk|walks]], then a family of centralities can be defined based on the length of walk considered.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;/&amp;gt; [[Centrality#Degree centrality|Degree centrality]] counts walks of length one, while [[Centrality#Eigenvector centrality|eigenvalue centrality]] counts walks of length infinity. Alternative definitions of association are also reasonable. [[Alpha centrality]] allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich showed that if association is defined in terms of walks, then a family of centralities can be defined based on the length of walk considered. Degree centrality counts walks of length one, while eigenvalue centrality counts walks of length infinity. Alternative definitions of association are also reasonable. Alpha centrality allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich 指出，如果联想是根据行走来定义的，那么可以根据考虑的行走长度来定义一个中心性家族。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''计算长度为1的行走，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征值中心性Eigenvalue centrality  &amp;lt;/font&amp;gt;'''计算长度为无穷大的行走。关联的其他定义也是合理的。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 阿尔法中心性Alpha centrality&amp;lt;/font&amp;gt;'''允许顶点有一个外部影响源。埃斯特拉达的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图中心性Subgraph centrality &amp;lt;/font&amp;gt;'''提出只计算封闭路径(三角形、正方形等)。).&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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这些测量方法的核心是这种现象：图中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵&amp;lt;/font&amp;gt;'''的幂给出了由该幂给出的散步长度的数目。同样，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 矩阵指数Matrix exponential&amp;lt;/font&amp;gt;'''也与给定长度的行走次数密切相关。邻接矩阵的初始转换允许对步行计数的类型进行不同的定义。无论采用哪种方法，顶点的中心性都可以表示为无穷和&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum _ { k = 0} ^ infty a _ { r } ^ { k } beta ^ k &amp;lt;/math &amp;gt; &lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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矩阵能量或者&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum { k = 0} ^ infty frac {(a _ r beta) ^ k }{ k！{/math &amp;gt; &lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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对于矩阵指数函数，其中&lt;br /&gt;
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* &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; is walk length,&lt;br /&gt;
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* &amp;lt;math&amp;gt;A_R&amp;lt;/math&amp;gt; is the transformed adjacency matrix, and&lt;br /&gt;
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* &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; is a discount parameter which ensures convergence of the sum.&lt;br /&gt;
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K为步长，A_R是邻接矩阵的转秩，贝达是保证收敛的折扣参数。&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. [[Alpha centrality]] replaces the adjacency matrix with its [[resolvent formalism|resolvent]]. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to [[Centrality#Degree centrality|degree centrality]]. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to [[Centrality#Eigenvector centrality|eigenvalue centrality]].&amp;lt;ref name=Benzi2013/&amp;gt;&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. Alpha centrality replaces the adjacency matrix with its resolvent. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to degree centrality. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to eigenvalue centrality.&lt;br /&gt;
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博纳奇的一系列措施并没有改变邻接矩阵。阿尔法集中性用它的解决方案替代了邻接矩阵。子图集中性用它的踪迹取代了邻接矩阵。一个令人吃惊的结论是，不管邻接矩阵最初的转变是什么，所有这些方法都有共同的限制行为。随着贝塔系数趋近于零，指数收敛到度中心性。随着贝塔系数接近其最大值，指数收敛到特征值的中心性。&lt;br /&gt;
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===Game-theoretic centrality===&lt;br /&gt;
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=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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上述大多数标准措施的共同特点是，它们通过只关注一个节点本身所扮演的角色来评估确定节点的重要性。然而, 在许多应用中，这种方法是不充分的，因为可能会发生协同作用&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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如果将节点的功能分组考虑。&lt;br /&gt;
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[[File:Game-theoretic centrality.png|Example of game-theoretic centrality]]&lt;br /&gt;
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Example of game-theoretic centrality&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''的例子&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in &amp;lt;ref&amp;gt;Michalak, Aadithya, Szczepański, Ravindran, &amp;amp; Jennings {{ArXiv|1402.0567}}&amp;lt;/ref&amp;gt; uses the [[Shapley value]]. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
&lt;br /&gt;
For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in  uses the Shapley value. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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例如，考虑阻止流行病的问题。看看上面的网络图像，我们应该给哪些节点接种疫苗？基于前面描述的措施，我们希望识别在疾病传播中最重要的节点。仅仅基于中心的方法，即关注节点的个别特性，可能不是一个好主意。红色方块中的节点，单独不能阻止疾病的传播，但把它们作为一个群体来考虑，我们清楚地看到，如果疾病在节点 &amp;lt; math &amp;gt; v _ 1 &amp;lt;/math &amp;gt; 、 &amp;lt; math &amp;gt; v _ 4 &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; v _ 5 &amp;lt;/math &amp;gt; 中开始，它们就能阻止疾病的传播。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''试图利用博弈论中的工具来研究所描述的问题和机会。本文提出的方法使用了 Shapley 值。由于 Shapley 值计算的时间复杂性，这一领域的大部分工作都集中在实现新的算法和方法，这些算法和方法依赖于网络的特殊拓扑结构或问题的特殊性质。这种方法可以将时间复杂度从指数级降低到多项式级。&lt;br /&gt;
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Similarly, the solution concept [[authority distribution]] (&amp;lt;ref&amp;gt;{{cite journal |last=Hu |first=Xingwei |first2=Lloyd |last2=Shapley |title=On Authority Distributions in Organizations |journal=Games and Economic Behavior |volume=45 |pages=132–170 |year=2003 | doi = 10.1016/s0899-8256(03)00130-1 }}&amp;lt;/ref&amp;gt;) applies the [[Shapley-Shubik power index]], rather than the [[Shapley value]], to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020)&amp;lt;ref&amp;gt;{{cite journal|last=Hu|first=Xingwei|year=2020|volume=7|title=Sorting big data by revealed preference with application to college ranking |journal=Journal of Big Data|doi=10.1186/s40537-020-00300-1|doi-access=free}}&amp;lt;/ref&amp;gt;, such as ranking U.S. colleges.&lt;br /&gt;
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Similarly, the solution concept authority distribution () applies the Shapley-Shubik power index, rather than the Shapley value, to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020), such as ranking U.S. colleges.&lt;br /&gt;
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同样，'''&amp;lt;font color=&amp;quot;#CD32CD&amp;quot;&amp;gt; 加权分布概念的解()The solution concept authority distribution () &amp;lt;/font&amp;gt;'''采用 Shapley-Shubik 幂指数，而不是 Shapley 值来衡量双方之间的直接影响。这种分布确实是一种产生'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征向量中心性Engenvector centrality&amp;lt;/font&amp;gt;'''的类型。它用于对 Hu (2020)中的大数据对象进行排序，比如美国大学排名。&lt;br /&gt;
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== Important limitations ==&lt;br /&gt;
==重要限制==&lt;br /&gt;
Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the [[Krackhardt kite graph]], for which three different notions of centrality give three different choices of the most central vertex.&amp;lt;ref&amp;gt;{{cite journal|title=Assessing the Political Landscape: Structure, Cognition, and Power in Organizations|first=David|last=Krackhardt|authorlink=David Krackhardt|journal=Administrative Science Quarterly|volume=35|issue=2|date=June 1990|pages=342–369|doi=10.2307/2393394|jstor=2393394}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the Krackhardt kite graph, for which three different notions of centrality give three different choices of the most central vertex.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中心性Centrality&amp;lt;/font&amp;gt;'''指标有两个重要的局限性，一个显而易见，另一个则不易察觉。显而易见的局限性是，对于一个应用最优的中心性对于另一个应用常常是次优的。事实上，如果不是这样，我们就不需要这么多不同的中心性。克拉克哈特风筝图为这一现象提供了一个例证，对于这个图，三个不同的中心性概念给出了三个最中心顶点的不同选择。&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices.&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=Borgatti2005/&amp;gt; This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  [[node influence metric]]s to address this problem.&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices. This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  node influence metrics to address this problem.&lt;br /&gt;
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更不易察觉的限制是通常会错误地认为顶点中心性表示顶点的相对重要性。中心性指数被明确地设计来产生一个指出最重要顶点的排名。在刚才提到的限制下，他们做得很好。它们通常不用来测量节点的影响力。最近，网络物理学家开始开发'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;节点影响度量Node influence metrics &amp;lt;/font&amp;gt;'''来解决这个问题。&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying [[Centrality#Freeman centralization|Freeman centralization]] to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt; This approach, however, is seldom seen in practice.{{citation needed|reason=I've come across quite some theoretical studies that indicate otherwise. My suggestion is to remove this sentence, if reasonable citation is not provided.|date=September 2015}}&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying Freeman centralization to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores. This approach, however, is seldom seen in practice.&lt;br /&gt;
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错误有两方面。首先，一个排名只根据顶点的重要性排序，它并不对节点重要性的不同水平进行量化区分。这可以通过将 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;'''应用到中心性度量来缓解，这种度量可以根据节点的不同中心性得分来判断节点的重要性。此外， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;''使人们能够通过比较几个网络的最高中心性得分来比较它们。然而，这种方法在实践中很少见到。&lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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其次，用以(正确地)识别给定网络/应用中最重要顶点的特征并不一定可推广到其余顶点。&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot; /&amp;gt;&amp;lt;ref name=&amp;quot;daSilva2012&amp;quot;&amp;gt;{{cite journal | last1=da Silva|first1=Renato |last2=Viana|first2=Matheus|last3=da F. Costa |first3=Luciano| title=Predicting epidemic outbreak from individual features of the spreaders| journal=J. Stat. Mech.: Theory Exp. | year=2012|volume=2012|pages=P07005|number=7 | doi=10.1088/1742-5468/2012/07/p07005|arxiv=1202.0024|bibcode=2012JSMTE..07..005A}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Bauer2012&amp;quot;&amp;gt;{{cite journal | last1=Bauer|first1=Frank | last2=Lizier|first2=Joseph|title=Identifying influential spreaders and efficiently estimating infection numbers in epidemic models: A walk counting approach| journal=Europhys Lett | year=2012| volume=99| pages=68007|number=6 | doi=10.1209/0295-5075/99/68007|arxiv=1203.0502|bibcode=2012EL.....9968007B}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Sikic2013&amp;quot;&amp;gt;{{ cite journal| last1= Sikic| first1=Mile|last2=Lancic|first2=Alen|last3=Antulov-Fantulin|first3=Nino|last4=Stefanic|first4=Hrvoje| title = Epidemic centrality -- is there an underestimated epidemic impact of network peripheral nodes? |journal = The European Physical Journal B |volume=86 |number=10 |pages=1–13 |year=2013 | doi=10.1140/epjb/e2013-31025-5|arxiv=1110.2558 | bibcode=2013EPJB...86..440S}}&amp;lt;/ref&amp;gt; This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&amp;lt;ref name=&amp;quot;Ghoshal2011&amp;quot;&amp;gt;{{cite journal | last1=Ghoshal | first1= G. | last2= Barabsi |first2= A L | title = Ranking stability and super-stable nodes in complex networks. | journal = Nat Commun | volume =2 | page = 394| year= 2011 | doi=10.1038/ncomms1396 | pmid= 21772265 | bibcode=2011NatCo...2..394G | doi-access= free }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless. This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&lt;br /&gt;
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对于大多数其他网络节点，排名可能是没有意义的。这就解释了为什么，例如，只有谷歌图片搜索的前几个结果以合理的顺序出现。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页排名Pagerank&amp;lt;/font&amp;gt;'''是一个非常不稳定的度量，显示了在跳转参数小的调整之后频繁的秩逆转。&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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虽然中心性指数未能推广到网络的其他部分，乍看起来似乎是违反直觉的，但它直接遵循上述定义。&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot;&amp;gt;{{cite journal |last1= Lawyer |first1= Glenn |year= 2015 |title= Understanding the spreading power of all nodes in a network: a continuous-time perspective |journal=Sci Rep |volume=5|pages=8665|doi=10.1038/srep08665 |pmid=25727453 |pmc=4345333|arxiv=1405.6707|bibcode=2015NatSR...5E8665L}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&lt;br /&gt;
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复杂网络具有异构的拓扑结构。由于最佳度量取决于最重要顶点的网络结构，对于这些顶点最优的度量对于网络的其余部分是次优的。&lt;br /&gt;
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==Degree centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Degree (graph theory)}} &lt;br /&gt;
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[[File:6 centrality measures.png|thumb|right|300px|Examples of A) [[Betweenness centrality]], B) [[Closeness centrality]], C) [[Eigenvector centrality]], D) [[Degree centrality]], E) [[Centrality#Harmonic centrality|Harmonic centrality]] and F) [[Katz centrality]] of the same graph.]]&lt;br /&gt;
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Examples of A) [[Betweenness centrality, B) Closeness centrality, C) Eigenvector centrality, D) Degree centrality, E) Harmonic centrality and F) Katz centrality of the same graph.]]&lt;br /&gt;
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实例 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; a)[中介中心性A) [[Betweenness centrality,b)紧密中心性，B) Closeness centrality, c)特征向量中心性，C) Eigenvector centrality, d)度中心性，D) Degree centrality, e)调和中心性，E) Harmonic centrality andf) 卡兹Katz 中心性]F) Katz centrality .]]&amp;lt;/font&amp;gt;'''&lt;br /&gt;
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Historically first and conceptually simplest is '''degree centrality''', which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely [[indegree]] and [[outdegree]]. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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Historically first and conceptually simplest is degree centrality, which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely indegree and outdegree. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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历史上最简单的概念是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''，它定义为一个节点上发生的链接数量(即一个节点拥有的关系数量)。度可以根据节点捕获流经网络的任何东西(例如病毒或某些信息)的直接风险来解释。在有向网络的情况下(其中联系有方向) ，我们通常定义两个独立的度量，即 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度 Outdegree&amp;lt;/font&amp;gt;'''。因此，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度indegree&amp;lt;/font&amp;gt;'''是指向该节点的关系数，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度outdegree&amp;lt;/font&amp;gt;'''是指该节点指向其他节点的关系数。当关系与一些积极的方面如友谊或合作有关时， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''通常被解释为一种形式的受欢迎，而 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度Indegree&amp;lt;/font&amp;gt;'''则被解释为合群。&lt;br /&gt;
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The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
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The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
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对于给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边，度的中心性定义为&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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Calculating degree centrality for all the nodes in a graph takes [[big theta|&amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt;]] in a [[dense matrix|dense]] [[adjacency matrix]] representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a [[sparse matrix]] representation.&lt;br /&gt;
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Calculating degree centrality for all the nodes in a graph takes &amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt; in a dense adjacency matrix representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a sparse matrix representation.&lt;br /&gt;
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计算一个图中所有节点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''需要在图的稠密'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵Adjacency matrix &amp;lt;/font&amp;gt;'''表示中使用 Theta (v ^ 2) &amp;lt;/math &amp;gt; ，而在稀疏矩阵表示中使用 Theta (e) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of ''graph centralization''.&amp;lt;ref&amp;gt;Freeman, Linton C. &amp;quot;Centrality in social networks conceptual clarification.&amp;quot; Social networks 1.3 (1979): 215–239.&amp;lt;/ref&amp;gt; Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
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The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of graph centralization. Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
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节点级中心性的定义可以扩展到整个图，在这种情况下，我们指的是图的集中性。设 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 为 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''最高的节点。让 &amp;lt; math &amp;gt; x: = (y，z) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; | y | &amp;lt;/math &amp;gt; 节点连接图，最大化下列数量(&amp;lt; math &amp;gt; y * &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 中度最高的节点) :&lt;br /&gt;
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:&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; h = sum ^ { | y | }{ j = 1}[ c _ d (y *)-c _ d (y _ j)] &amp;lt;/math &amp;gt; &lt;br /&gt;
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Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
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Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
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相应地，图形 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''如下:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ h } &amp;lt;/math &amp;gt; &lt;br /&gt;
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The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a [[star graph]]), and in this case&lt;br /&gt;
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The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a star graph), and in this case&lt;br /&gt;
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当图形 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 包含一个所有其他节点都连接的中心节点(一个星形图)时，&amp;lt; math &amp;gt; h &amp;lt;/math &amp;gt; 的值最大化，在这种情况下&lt;br /&gt;
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:&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
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(n-1)-1) = n ^ 2-3n + 2&lt;br /&gt;
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So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
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So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
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所以，对于任意的图 &amp;lt; math &amp;gt; g: = (v，e) ，&amp;lt;/math &amp;gt; &lt;br /&gt;
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:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ | v | ^ 2-3 | v | + 2} &amp;lt;/math &amp;gt;&lt;br /&gt;
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==Closeness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Closeness centrality}}In a [[Connected component (graph theory)|connected]] [[Graph (discrete mathematics)|graph]], the [[Normalization (statistics)|normalized]] '''closeness centrality''' (or '''closeness''') of a node is the average length of the [[Shortest path problem|shortest path]] between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
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In a connected graph, the normalized closeness centrality (or closeness) of a node is the average length of the shortest path between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
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在连通图中，节点的标准'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''(或贴近性)是节点与图中所有其他节点之间最短路径的平均长度。因此，一个节点越是中心，它就越接近所有其他节点。&lt;br /&gt;
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Closeness was defined by [[Alex Bavelas]] (1950) as the [[Multiplicative inverse|reciprocal]] of the '''farness''',&amp;lt;ref&amp;gt;Alex Bavelas. Communication patterns in task-oriented groups. ''J. Acoust. Soc. Am'', '''22'''(6):725–730, 1950.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;{{cite journal|year=1966|title=The centrality index of a graph|url=|journal=Psychometrika|volume=31|issue=4|pages=581–603|doi=10.1007/bf02289527|pmid=5232444|hdl=10338.dmlcz/101401|last1=Sabidussi|first1=G|hdl-access=free}}&amp;lt;/ref&amp;gt; that is:&lt;br /&gt;
&lt;br /&gt;
Closeness was defined by Alex Bavelas (1950) as the reciprocal of the farness, that is:&lt;br /&gt;
&lt;br /&gt;
亚历克斯 · 巴维拉斯(1950)将亲密度定义为相对于距离的倒数，即:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
C (x) = frac {1}{ sum _ y d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the [[Distance (graph theory)|distance]] between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the distance between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; d (y，x) &amp;lt;/math &amp;gt; 是顶点 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; 之间的距离。然而，当谈到'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''时，人们通常会提到它的标准化形式，一般是以前的公式乘以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; ，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。这种调整允许比较不同大小图形的节点。&lt;br /&gt;
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Taking distances ''from'' or ''to'' all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in [[directed graph]]s (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
&lt;br /&gt;
Taking distances from or to all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in directed graphs (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
&lt;br /&gt;
从所有其他节点或到所有其他节点的距离在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 无向图Undirected graphs&amp;lt;/font&amp;gt;'''中是不相关的，但是在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 有向图Directed graphs&amp;lt;/font&amp;gt;'''中可能产生完全不同的结果(例如:一个网站可以从传出链接获得高的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，而从传入链接获得低的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''）。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
===Harmonic centrality===&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the '''harmonic centrality''' reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the harmonic centrality reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
在一个(不一定是连通的)图中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''反转了'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''定义中的和互反运算:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h (x) = sum { y neq x } frac {1}{ d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; 1/d (y，x) = 0 &amp;lt;/math &amp;gt; if there is no path from &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; to &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 。调和中心性可以通过除以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; 来标准化，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。&lt;br /&gt;
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&lt;br /&gt;
&lt;br /&gt;
Harmonic centrality was proposed by [[Massimo Marchiori|Marchiori]] and [[Vito Latora|Latora]] (2000)&amp;lt;ref name=&amp;quot;marchiorilatora2000&amp;quot;&amp;gt;{{citation| journal = Physica A: Statistical Mechanics and Its Applications  | last1 = Marchiori | first1 = Massimo | last2 = Latora | first2 = Vito | year = 2000 | volume = 285 | issue = 3–4 | pages = 539–546 | title = Harmony in the small-world | doi=10.1016/s0378-4371(00)00311-3| arxiv = cond-mat/0008357 | bibcode = 2000PhyA..285..539M }}&amp;lt;/ref&amp;gt; and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot;&amp;lt;ref&amp;gt;{{cite journal|first1=Anthony|last1=Dekker|title=Conceptual Distance in Social Network Analysis|journal=Journal of Social Structure|volume=6|issue=3|year=2005|url=http://www.cmu.edu/joss/content/articles/volume6/dekker/index.html}}&amp;lt;/ref&amp;gt; and by Rochat (2009).&amp;lt;ref&amp;gt;{{cite conference  | author = Yannick Rochat  | title = Closeness centrality extended to unconnected graphs: The harmonic centrality index | conference = Applications of Social Network Analysis, ASNA 2009 | url = http://infoscience.epfl.ch/record/200525/files/%5bEN%5dASNA09.pdf }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Harmonic centrality was proposed by Marchiori and Latora (2000) and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot; and by Rochat (2009).&lt;br /&gt;
&lt;br /&gt;
调和中心性是由 Marchiori 和 Latora (2000)提出的，然后是 Dekker (2005)独立提出的，使用的名称是“有价值的中心性” ，Rochat (2009)。&lt;br /&gt;
&lt;br /&gt;
==Betweenness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Betweenness centrality}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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[[File:Graph betweenness.svg|240px|right|thumb|Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.]]&lt;br /&gt;
&lt;br /&gt;
Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.&lt;br /&gt;
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色调(从红色 = 0到蓝色 = max)表示节点之间的距离。&lt;br /&gt;
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&lt;br /&gt;
'''Betweenness''' is a centrality measure of a [[vertex (graph theory)|vertex]] within a [[Graph (discrete mathematics)|graph]] (there is also [[edge (graph theory)|edge]] betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by [[Linton Freeman]]&amp;lt;ref name=&amp;quot;freeman1977&amp;quot;&amp;gt;{{cite journal |last1 = Freeman |first1 = Linton | year=1977| title = A set of measures of centrality based upon betweenness | journal = Sociometry| volume=40|issue = 1 | pages=35–41 | doi=10.2307/3033543|jstor = 3033543 }}&amp;lt;/ref&amp;gt; In his conception, vertices that have a high probability to occur on a randomly chosen [[shortest path problem|shortest path]] between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
&lt;br /&gt;
Betweenness is a centrality measure of a vertex within a graph (there is also edge betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by Linton Freeman In his conception, vertices that have a high probability to occur on a randomly chosen shortest path between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
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中介性是图中顶点的中心性度量(也有边中介性，这里没有讨论)。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''量化了一个节点沿着其他两个节点之间的最短路径充当桥梁的次数。在林顿 · 弗里曼的概念中，在两个随机选择的顶点之间随机选择的最短路径上出现概率高的顶点具有很高的中介性。&lt;br /&gt;
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The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
&lt;br /&gt;
The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
&lt;br /&gt;
在一个图 &amp;lt; math &amp;gt; g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的顶点之间的距离计算如下:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
# For each pair of vertices (''s'',''t''), compute the [[Shortest path problem|shortest paths]] between them.&lt;br /&gt;
&lt;br /&gt;
 For each pair of vertices (s,t), compute the shortest paths between them.&lt;br /&gt;
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对于每一对顶点(s，t) ，计算它们之间的最短路径。&lt;br /&gt;
&lt;br /&gt;
# For each pair of vertices (''s'',''t''), determine the fraction of shortest paths that pass through the vertex in question (here, vertex ''v'').&lt;br /&gt;
&lt;br /&gt;
 For each pair of vertices (s,t), determine the fraction of shortest paths that pass through the vertex in question (here, vertex v).&lt;br /&gt;
&lt;br /&gt;
对于每对顶点(s，t) ，确定通过该顶点(这里是顶点 v)的最短路径的分数。&lt;br /&gt;
&lt;br /&gt;
# Sum this fraction over all pairs of vertices (''s'',''t'').&lt;br /&gt;
&lt;br /&gt;
 Sum this fraction over all pairs of vertices (s,t).&lt;br /&gt;
&lt;br /&gt;
对所有顶点对(s，t)求这个分数的和。&lt;br /&gt;
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More compactly the betweenness can be represented as:&amp;lt;ref name=&amp;quot;brandes&amp;quot;&amp;gt;{{cite journal |last1 = Brandes |first1 = Ulrik | year=2001 |title = A faster algorithm for betweenness centrality  | journal = Journal of Mathematical Sociology| volume=25|issue = 2 | pages=163–177| url = http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.11.2024 | accessdate = October 11, 2011| format = PDF | doi=10.1080/0022250x.2001.9990249|citeseerx = 10.1.1.11.2024 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
More compactly the betweenness can be represented as:&lt;br /&gt;
&lt;br /&gt;
更确切地说，两者之间的关系可以表示为:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
{ math &amp;gt; c _ b (v) = sum _ { s neq v neq t in v } frac { sigma _ st }(v)}{ sigma _ st } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including ''v'', which for [[Digraph (mathematics)|directed graphs]] is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected [[Star (graph theory)|star graph]], the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including v, which for directed graphs is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected star graph, the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; sigma { st } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { st }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径数。有向图是 &amp;lt; math &amp;gt; (n-1)(n-2) &amp;lt;/math &amp;gt; ，无向图是 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; 。例如，在一个无向星图中，中心顶点(包含在每个可能的最短路径中)的中介性为 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; (1，如果标准化) ，而叶子(包含在没有最短路径中)的中介性为0。&lt;br /&gt;
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&lt;br /&gt;
&lt;br /&gt;
From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires [[Big O notation|&amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt;]] time with the [[Floyd–Warshall algorithm]]. However, on sparse graphs, [[Johnson's algorithm]] may be more efficient, taking [[Big O notation|&amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt;]] time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm&amp;lt;ref name=brandes/&amp;gt; which takes [[Big O notation|&amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt;]] time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&amp;lt;ref name=&amp;quot;brandes&amp;quot; /&amp;gt;&lt;br /&gt;
&lt;br /&gt;
From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires &amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt; time with the Floyd–Warshall algorithm. However, on sparse graphs, Johnson's algorithm may be more efficient, taking &amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt; time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm which takes &amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt; time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&lt;br /&gt;
&lt;br /&gt;
从计算的角度来看，图中所有顶点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介和紧密中心性Betweenness and Closeness centralities&amp;lt;/font&amp;gt;'''都涉及到计算图中所有顶点对之间的最短路径，这就需要用 Floyd-Warshall 算法计算时间。然而，对于稀疏图，约翰逊算法的效率可能更高，采用 &amp;lt; math &amp;gt; o (v ^ 2 log v + v e) &amp;lt;/math &amp;gt; 时间。在不加权图的情况下，可以用 Brandes 的算法进行计算，该算法需要 &amp;lt; math &amp;gt; o (v e) &amp;lt;/math &amp;gt; 时间。一般情况下，这些算法假定图是无向的，并且连通图中允许有圈和多条边。当专门处理网络图时，图通常没有环或多条边来维持简单的关系(其中的边表示两个人或顶点之间的联系)。在这种情况下，使用 Brandes 的算法将最终的中心性分数除以2来计算每条被重复计算的最短路径。&lt;br /&gt;
&lt;br /&gt;
==Eigenvector centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Eigenvector centrality}}&lt;br /&gt;
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'''Eigenvector centrality''' (also called '''eigencentrality''') is a measure of the influence of a [[node (networking)|node]] in a [[network (mathematics)|network]]. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&amp;lt;ref&amp;gt;{{cite journal|title = The mathematics of networks|url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf|author = M. E. J. Newman|accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;/&amp;gt; [[Google]]'s [[PageRank]] and the [[Katz centrality]] are variants of the eigenvector centrality.&amp;lt;ref name=&amp;quot;ams&amp;quot;&amp;gt;{{Cite web | url=http://www.ams.org/samplings/feature-column/fcarc-pagerank | title=American Mathematical Society}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Eigenvector centrality (also called eigencentrality) is a measure of the influence of a node in a network. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''(也称为特征中心性)是衡量网络中节点影响的一个指标。它将相对得分分配给网络中的所有节点，这是基于这样一个概念: 与得分较高的节点相比，与得分较低的节点相同的连接对所涉及的节点的得分贡献更大。&lt;br /&gt;
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=== Using the adjacency matrix to find eigenvector centrality ==&lt;br /&gt;
==使用'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''发现'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the [[adjacency matrix]], i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
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For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the adjacency matrix, i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
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对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 让 &amp;lt; math &amp;gt; a = (a { v，t }) &amp;lt;/math &amp;gt; 成为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''，即。如果顶点 &amp;lt; math &amp;gt; &amp;gt; v &amp;lt;/math &amp;gt; 与 math &amp;gt; t &amp;lt;/math &amp;gt; 相连，而 &amp;lt; math &amp;gt; a { v，t } = 0 &amp;lt;/math &amp;gt; 否则。顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分可以定义为:&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
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在 m (v)} x _ t = frac {1}{ lambda } sum { t in g } a { v，t } x _ t &amp;lt;/math &amp;gt; &lt;br /&gt;
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where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the [[eigenvector]] equation&lt;br /&gt;
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where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the eigenvector equation&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; m (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 和 &amp;lt; math &amp;gt; &amp;gt; lambda &amp;lt;/math &amp;gt; 的邻居集合。通过一个小的重新排列，这可以被重写成向量符号，作为特征向量方程&lt;br /&gt;
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:&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
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[ math &amp;gt; mathbf { Ax } = { lambda } mathbf { x } &amp;lt;/math &amp;gt; &lt;br /&gt;
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In general, there will be many different [[eigenvalue]]s &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the [[Perron–Frobenius theorem]]. This greatest eigenvalue results in the desired centrality measure.&amp;lt;ref&amp;gt;{{cite journal  | author = M. E. J. Newman  | title = The mathematics of networks  | url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf  | accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt; The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices ''n''. [[Power iteration]] is one of many [[eigenvalue algorithm]]s that may be used to find this dominant eigenvector.&amp;lt;ref name=&amp;quot;ams&amp;quot; /&amp;gt; Furthermore, this can be generalized so that the entries in ''A'' can be real numbers representing connection strengths, as in a [[stochastic matrix]].&lt;br /&gt;
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In general, there will be many different eigenvalues &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the Perron–Frobenius theorem. This greatest eigenvalue results in the desired centrality measure. The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices n. Power iteration is one of many eigenvalue algorithms that may be used to find this dominant eigenvector. Furthermore, this can be generalized so that the entries in A can be real numbers representing connection strengths, as in a stochastic matrix.&lt;br /&gt;
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一般情况下，存在许多不同的特征值，对于这些特征值存在一个非零特征向量解。由于邻接矩阵中的条目是非负的，所以由 Perron-弗罗贝尼乌斯定理得出，它有一个实的和正的唯一最大特征值。由这个最大的特征值得出期望的中心性度量。相关特征向量的 &amp;lt; math &amp;gt; v ^ { th } &amp;lt;/math &amp;gt; 分量给出了网络中顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分。特征向量只定义了一个公共因子，所以只有顶点中心的比例是明确定义的。要定义一个绝对分数，必须对特征向量进行标准化，例如，使所有顶点的和为1或顶点的总数n。此外，这可以通用，使得 a 中的条目可以是表示连接强度的真实数字，就像'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 随机矩阵Stochastic matrix&amp;lt;/font&amp;gt;'''中一样。&lt;br /&gt;
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==Katz centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Katz centrality}}&lt;br /&gt;
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'''Katz centrality'''&amp;lt;ref&amp;gt;Katz, L. 1953. A New Status Index Derived from Sociometric Index. Psychometrika, 39–43.&amp;lt;/ref&amp;gt; is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
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Katz centrality is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''是度中心性的推广。度中心性度量的是直接邻居的数量，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''度量的是通过一条路径可以连接的所有节点的数量，而远处节点的贡献会受到'''&amp;lt;font color=&amp;quot;#32CD32&amp;quot;&amp;gt; '削弱（惩罚？）Penalized&amp;lt;/font&amp;gt;''。在数学上，它被定义为&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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[数学][数学]&lt;br /&gt;
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where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; (0,1) &amp;lt;/math &amp;gt; 中的衰减因子。&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''可以看作是特征向量中心性的变体。Katz 中心性的另一种形式是&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
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(x _ j + 1) &lt;br /&gt;
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Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
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Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
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与特征向量中心性的表达式相比，&amp;lt; math &amp;gt; x _ j &amp;lt;/math &amp;gt; 被 &amp;lt; math &amp;gt; x _ j + 1所代替&lt;br /&gt;
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It is shown that&amp;lt;ref&amp;gt;{{cite journal | last1 = Bonacich | first1 = P | year = 1991 | title = Simultaneous group and individual centralities | url = | journal = Social Networks | volume = 13 | issue = 2| pages = 155–168 | doi=10.1016/0378-8733(91)90018-o}}&amp;lt;/ref&amp;gt; the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
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It is shown that the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
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结果表明，主特征向量(与 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; ，邻接矩阵的最大特征值相关)是 Katz 中心性的极限，因为 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 接近 &amp;lt; math &amp;gt; tfrac {1}{ lambda } &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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== PageRank centrality ==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页分布中心性PageRank&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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{{main|PageRank}}'''[[PageRank]]''' satisfies the following equation&lt;br /&gt;
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PageRank satisfies the following equation&lt;br /&gt;
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PageRank满足下面的等式&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
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1-alpha { n } ，&amp;lt;/math &amp;gt; &lt;br /&gt;
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where&lt;br /&gt;
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where&lt;br /&gt;
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其中&lt;br /&gt;
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:&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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[ math &amp;gt; l (j) = sum { i } a { ji } &amp;lt;/math &amp;gt; &lt;br /&gt;
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is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&amp;lt;ref&amp;gt;[http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf How does Google rank webpages?] {{webarchive | url= https://web.archive.org/web/20120131083328/http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf |date=January 31, 2012 }} 20Q: About Networked Life&amp;lt;/ref&amp;gt;&lt;br /&gt;
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is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&lt;br /&gt;
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是节点 &amp;lt; math &amp;gt; j &amp;lt;/math &amp;gt; (或有向图中出站链接的数量)的邻居数量。与特征向量中心性和 Katz 中心性相比，尺度因子 &amp;lt; math &amp;gt; l (j) &amp;lt;/math &amp;gt; 是一个主要的区别。PageRank 和特征向量中心性的另一个区别是 PageRank 向量是一个左手特征向量(注意因子 &amp;lt; math &amp;gt; a _ { ji } &amp;lt;/math &amp;gt; 具有相反的索引)。&lt;br /&gt;
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==Percolation centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&amp;lt;ref name=&amp;quot;piraveenan2013&amp;quot;&amp;gt;{{cite journal |last1 = Piraveenan |first1 = M. |last2 = Prokopenko |first2 = M.|last3 = Hossain|first3 = L. |year=2013| title = Percolation Centrality: Quantifying Graph-Theoretic Impact of Nodes during Percolation in Networks | journal = PLOS One | volume=8 | issue=1 | doi=10.1371/journal.pone.0053095 | pages=e53095 | pmid=23349699 | pmc=3551907| bibcode=2013PLoSO...853095P }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&lt;br /&gt;
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在复杂网络中，存在大量的中心性度量来确定单个节点的“重要性”。然而，这些度量单纯从拓扑学的角度来量化节点的重要性，节点的值并不以任何方式依赖于节点的状态。不管网络动态如何，它都保持不变。即使对于加权的两者之间的度量也是如此。然而，一个节点可能很好地位于'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''或其他中心性度量的中心位置，但可能不是位于有过滤的网络的上下文中的中心位置。在许多情况下，复杂网络中都会出现“传染”现象。例如，病毒或细菌感染可以通过人们的社交网络传播，也就是所谓的接触网络。还可以在更高的抽象层次上考虑疾病的传播问题，设想通过公路、铁路或空中连接起来的城镇或人口中心网络。计算机病毒可以通过计算机网络传播。关于商业活动和交易的谣言或新闻也可以通过人们的社交网络传播。在所有这些情况下，一种“传染病”在一个复杂网络的链接上传播，随着它的传播，无论是可恢复的还是不可恢复的，都会改变节点的“状态”。例如，在流行病学方案中，随着感染扩散，个人从”易感”状态转变为”受感染”状态。在上面的例子中，随着传染的扩散，每个节点可以采取的状态可以是二进制的(例如接收/没有接收到一条新闻)、离散的(易感/受感染/康复) ，甚至是连续的(例如一个城镇中受感染的人的比例) 。这些情景的共同特点是，传染的扩散导致网络中节点状态的改变。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''（PC)就是基于这个思想而提出的，它特别地衡量了节点在协助网络渗滤方面的重要性。这项措施是由 piraveanan 等人提出的。&lt;br /&gt;
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'''Percolation centrality''' is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
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Percolation centrality is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''定义为在给定时间内一个给定节点的过滤路径的比例。“渗滤路径”是一对节点之间的最短路径，其中源节点被渗滤(例如，被感染)。目标节点可以是过滤的或非过滤的，或处于部分过滤状态。&lt;br /&gt;
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:&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; PC ^ t (v) = frac {1}{ N-2} sum { s neq v neq r } frac { sigma { sr }(v)}{ sigma { sr }} frac { x ^ t }{ sum {[{ x ^ t } i }}}]}}-{ x ^ t }{ v } &amp;lt;/math &amp;gt; &lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; σ { sr } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; r &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { sr }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径的总数。在时间 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 时，节点的过滤状态用 &amp;lt; math &amp;gt; { x ^ t } _ i &amp;lt;/math &amp;gt; 表示，两个特殊情况是当 &amp;lt; math &amp;gt; { x ^ t } _ i = 0 &amp;lt;/math &amp;gt; 表示在时间上是非过滤状态，而当 &amp;lt; math &amp;gt; &amp;lt; x ^ t &amp;lt;/math &amp;gt; i = 1 &amp;lt;/math &amp;gt; 表示在时间上是完全过滤状态。两者之间的值表示部分过滤状态(例如，在一个城镇网络中，这是该城镇感染者的百分比)。&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in [[Big O notation|&amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt;]] time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is [[Big O notation|&amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;]].&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in &amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt; time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is &amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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渗流路径的权重取决于分配给源节点的渗流水平，前提是源节点的渗流水平越高，源节点的路径就越重要。因此，位于源自高渗滤节点的最短路径上的节点可能对渗滤更为重要。PC 的定义也可以扩展到包括目标节点的权重。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''计算运行在 &amp;lt; math &amp;gt; o (NM) &amp;lt;/math &amp;gt; 时间，采用了 Brandes 快速算法的有效实现，如果计算需要考虑目标节点的权重，最坏情况下时间为 &amp;lt; math &amp;gt; o (n ^ 3) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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==Cross-clique centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 交叉团中心性Cross-clique centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
'''Cross-clique centrality''' of a single node in a complex graph determines the connectivity of a node to different [[clique (graph theory)|clique]]s. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in &amp;lt;ref name=&amp;quot;xssworms&amp;quot;&amp;gt;{{cite journal |last1 = Faghani|first1 = Mohamamd Reza| year=2013| title = A Study of XSS Worm Propagation and Detection Mechanisms in Online Social Networks | journal = IEEE Transactions on Information Forensics and Security|volume = 8|issue = 11|pages = 1815–1826|doi = 10.1109/TIFS.2013.2280884}}&amp;lt;/ref&amp;gt; but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
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Cross-clique centrality of a single node in a complex graph determines the connectivity of a node to different cliques. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in  but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
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复杂图中单个节点的跨团中心性决定了一个节点与不同团的连通性。具有高度跨团连通性的节点有利于信息或疾病在图中的传播。团是一种'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图Subgraphs&amp;lt;/font&amp;gt;'''，团中的每个节点都与团中的其他节点相连。对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边的交叉团连通性，定义为 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; x (v) &amp;lt;/math &amp;gt; 其中 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 所属的顶点团数。这个测度应用日久，但是在1998年由 Everett 和 Borgatti 首次提出，他们称之为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 派系重叠中心性Clique-overlap centrality&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Freeman centralization==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心度Freeman centralization&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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The '''centralization''' of any network is a measure of how central its most central node is in relation to how central all the other nodes are.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;&amp;gt;{{citation | journal = Social Networks | last1 = Freeman | first1 = Linton C. | year = 1979 | volume = 1 | issue = 3 | pages = 215–239 | title = centrality in social networks: Conceptual clarification | url = http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | doi = 10.1016/0378-8733(78)90021-7 | citeseerx = 10.1.1.227.9549 | access-date = 2014-07-31 | archive-url = https://web.archive.org/web/20160222033108/http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | archive-date = 2016-02-22 | url-status = dead }}&amp;lt;/ref&amp;gt; Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
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The centralization of any network is a measure of how central its most central node is in relation to how central all the other nodes are. Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
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任何网络的集中度都是衡量其最核心的节点相对于其他所有节点的集聚程度的标准。集中度的度量方法是: (a)计算网络中最中心的节点与所有其他节点之间的中心性差异之和; (b)将这个数量除以理论上相同规模的任何网络中这种差异之和的最大值。因此，每个中心性度量都可以有自己的集中性度量。正式定义，如果 &amp;lt; math &amp;gt; c _ x (p _ i) &amp;lt;/math &amp;gt; 是点 &amp;lt; math &amp;gt; i &amp;lt;/math &amp;gt; 的中心性度量，如果 &amp;lt; math &amp;gt; c _ x (p _ *) &amp;lt;/math &amp;gt; 是网络中最大的中心性度量，如果:&lt;br /&gt;
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:&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; max sum { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i) &amp;lt;/math &amp;gt; &lt;br /&gt;
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is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;&lt;br /&gt;
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is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&lt;br /&gt;
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对于任何具有相同节点数的图来说，点中心性的最大差异是:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; c _ x = frac { sum _ { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i)}{ max sum _ { i = 1 ^ { n } c _ x (p _ *)-c _ x (p _ i)} . &amp;lt;/math &amp;gt;&lt;br /&gt;
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== Dissimilarity based centrality measures ==&lt;br /&gt;
==基于相异性的中心性度量==&lt;br /&gt;
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[[File:Srep17095-f1.jpg|thumbnail|In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.]]&lt;br /&gt;
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In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.&lt;br /&gt;
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在图示的网络中，绿色节点和红色节点最不相似，因为它们之间不共享相邻节点。因此，绿色的节点比灰色的节点对中心性的贡献更大，因为红色的节点只能通过绿色访问蓝色的节点，而灰色的节点对于红色的节点是多余的，因为它可以直接访问每个灰色的节点，而不需要任何中介。&lt;br /&gt;
&lt;br /&gt;
In order to obtain better results in the ranking of the nodes of a given network,  in &amp;lt;ref&amp;gt;{{Cite journal|title = Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|journal = Scientific Reports|date = 2015-11-25|pmc = 4658528|pmid = 26603652|volume = 5|doi = 10.1038/srep17095|first = A. J.|last = Alvarez-Socorro|first2 = G. C.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz|pages=17095|bibcode = 2015NatSR...517095A}}&amp;lt;/ref&amp;gt; are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with [[eigenvector centrality]], calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
&lt;br /&gt;
In order to obtain better results in the ranking of the nodes of a given network,  in  are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with eigenvector centrality, calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
&lt;br /&gt;
为了在给定网络节点的排序中获得更好的结果，在复杂网络中使用了相异性度量(特定于分类和数据挖掘理论)来丰富中心性度量。特征向量中心性通过求解特征值问题来计算每个节点的中心性&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
数学，数学&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary [[Matrix similarity|dissimilarity]] matrix, defined through a dissimilitary measure, e.g., [[Jaccard index|Jaccard]] dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary dissimilarity matrix, defined through a dissimilitary measure, e.g., Jaccard dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
这里 &amp;lt; math &amp;gt; w { ij } = a { ij } d { ij } &amp;lt;/math &amp;gt; (coordinate-to-coordinate product)和 &amp;lt; math &amp;gt; d { ij } &amp;lt;/math &amp;gt; 是一个任意的不相似矩阵，通过一个双重军事度量来定义，例如，Jaccard 由&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1-dfrac { | v ^ { + }(i) cap v ^ { + }(j) | }{ | v ^ { + }(i) cup v ^ { + }(j) | } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
&lt;br /&gt;
Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
&lt;br /&gt;
这种度量允许我们量化每个节点对给定节点中心性的拓扑贡献(这就是为什么我们称之为贡献中心性) ，对那些相异性较大的节点有更多的权重/相关性，因为这些节点允许给定的节点访问那些它们自己不能直接访问的节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the [[Perron–Frobenius theorem]] to ensure that the above problem has a unique solution for ''λ'' = ''λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt;'' with '''c''' non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
&lt;br /&gt;
Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the Perron–Frobenius theorem to ensure that the above problem has a unique solution for λ = λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt; with c non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
&lt;br /&gt;
值得注意的是，&amp;lt; math &amp;gt; w &amp;lt;/math &amp;gt; 是非负的，因为 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; d &amp;lt;/math &amp;gt; 都是非负矩阵，所以我们可以使用 Perron 弗罗贝尼乌斯定理来确保上述问题对于 c 非负的 = &amp;lt; sub &amp;gt; max &amp;lt;/sub &amp;gt; 有唯一的解，这样我们就可以推断出网络中每个节点的中心性。因此，i-th 节点的中心性为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1{ n } sum { j = 1} ^ { n } w { ij } c { j } ，，，，，j = 1，cdots，n &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in &amp;lt;ref&amp;gt;{{Cite web|url = http://www.nature.com/article-assets/npg/srep/2015/151125/srep17095/extref/srep17095-s1.pdf|title = Supplementary Information for Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|date = |website = |publisher = Nature Publishing Group|last = Alvarez-Socorro|first = A.J.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz}}&amp;lt;/ref&amp;gt; obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in  obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是网络中的节点数。几个不同的措施和网络进行了测试，以获得在研究案例的改善的结果。&lt;br /&gt;
&lt;br /&gt;
==Extensions==&lt;br /&gt;
==扩展==&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality&amp;lt;ref&amp;gt;{{cite journal | last1 = Braha | first1 = D. | last2 = Bar-Yam | first2 = Y. | year = 2006 | title = From Centrality to Temporary Fame: Dynamic Centrality in Complex Networks | url = | journal = Complexity | volume = 12 | issue = 2| pages = 59–63 | doi=10.1002/cplx.20156| arxiv = physics/0611295 | bibcode = 2006Cmplx..12b..59B }}&amp;lt;/ref&amp;gt; in the context of time-dependent and temporal networks.&amp;lt;ref&amp;gt;{{cite journal | last1 = Hill | first1 = S.A. | last2 = Braha | first2 = D. | year = 2010 | title = Dynamic Model of Time-Dependent Complex Networks | url = | journal = Physical Review E | volume = 82 | issue = 4| page = 046105 | doi=10.1103/physreve.82.046105| pmid = 21230343 | arxiv = 0901.4407 | bibcode = 2010PhRvE..82d6105H }}&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Gross, T. and Sayama, H. (Eds.). 2009. ''Adaptive Networks: Theory, Models and Applications.'' Springer.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Holme, P. and Saramäki, J. 2013. ''Temporal Networks.'' Springer.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality in the context of time-dependent and temporal networks.&lt;br /&gt;
&lt;br /&gt;
经验和理论研究已经将静态网络中的中心性概念扩展到时间依赖网络和时间网络中的动态中心性。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&amp;lt;ref&amp;gt;{{cite journal | last1 = Opsahl | first1 = Tore | last2 = Agneessens | first2 = Filip | last3 = Skvoretz | first3 = John | title = Node centrality in weighted networks: Generalizing degree and shortest paths | doi = 10.1016/j.socnet.2010.03.006 | year = 2010 | pages = 245–251 | volume = 32 | journal = Social Networks | url = http://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | issue = 3 | access-date = 2010-04-23 | archive-url = https://web.archive.org/web/20180226080331/https://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | archive-date = 2018-02-26 | url-status = dead }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&lt;br /&gt;
&lt;br /&gt;
对加权网络的推广，见 Opsahl 等人。(2010).&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, '''group betweenness''' centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&amp;lt;ref name=&amp;quot;group1&amp;quot;&amp;gt;Everett, M. G. and Borgatti, S. P. (2005). Extending centrality. In P. J. Carrington, J. Scott and S. Wasserman (Eds.), ''Models and methods in social network analysis'' (pp. 57–76). New York: Cambridge University Press.&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;group2&amp;quot;&amp;gt;Puzis, R., Yagil, D., Elovici, Y., Braha, D. (2009).[http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf Collaborative attack on Internet users’ anonymity] {{Webarchive|url=https://web.archive.org/web/20131207133417/http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf |date=2013-12-07 }}, ''Internet Research'' '''19'''(1)&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, group betweenness centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&lt;br /&gt;
&lt;br /&gt;
中心性的概念也扩展到了群体层次。例如，组间的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''显示了连接穿过组的成对非组成员的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Geodesics &amp;lt;/font&amp;gt;'''的比例。&lt;br /&gt;
&lt;br /&gt;
==See also==&lt;br /&gt;
==又及==&lt;br /&gt;
* [[Alpha centrality]]&lt;br /&gt;
&lt;br /&gt;
* [[Core–periphery structure]]&lt;br /&gt;
&lt;br /&gt;
* [[Distance (graph theory)|Distance in graphs]]&lt;br /&gt;
&lt;br /&gt;
*阿尔法中心性&lt;br /&gt;
&lt;br /&gt;
*核心—外围结构&lt;br /&gt;
&lt;br /&gt;
*距离（图理论）图中的距离&lt;br /&gt;
&lt;br /&gt;
==Notes and references==&lt;br /&gt;
&lt;br /&gt;
{{Reflist}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Further reading==&lt;br /&gt;
拓展阅读&lt;br /&gt;
* Koschützki, D.; Lehmann, K. A.; Peeters, L.; Richter, S.; Tenfelde-Podehl, D. and Zlotowski, O. (2005) Centrality Indices. In Brandes, U. and Erlebach, T. (Eds.)  ''Network Analysis: Methodological Foundations'', pp.&amp;amp;nbsp;16–61, LNCS 3418, Springer-Verlag.&lt;br /&gt;
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[[Category:Graph theory]]&lt;br /&gt;
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Category:Graph theory&lt;br /&gt;
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分类: 图论&lt;br /&gt;
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[[Category:Graph algorithms]]&lt;br /&gt;
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Category:Graph algorithms&lt;br /&gt;
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分类: 图形算法&lt;br /&gt;
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[[Category:Algebraic graph theory]]&lt;br /&gt;
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Category:Algebraic graph theory&lt;br /&gt;
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分类: 代数图论&lt;br /&gt;
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[[Category:Networks]]&lt;br /&gt;
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Category:Networks&lt;br /&gt;
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分类: 网络&lt;br /&gt;
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[[Category:Network analysis]]&lt;br /&gt;
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Category:Network analysis&lt;br /&gt;
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分类: 网络分析&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Centrality]]. Its edit history can be viewed at [[网络中心性/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
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		<title>网络中心性</title>
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		<updated>2020-12-10T07:10:00Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* 中心性指数的定义与特性Definition and characterization of centrality indices */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;此词条暂由水流心不竞初译，未经审校，带来阅读不便，请见谅。&lt;br /&gt;
&lt;br /&gt;
{{for|the statistical concept|Central tendency}}&lt;br /&gt;
{{Network Science}}&lt;br /&gt;
&lt;br /&gt;
In [[graph theory]] and [[network theory|network analysis]], indicators of '''centrality''' identify the most important [[vertex (graph theory)|vertices]] within a graph. Applications include identifying the most influential person(s) in a [[social network]], key infrastructure nodes in the [[Internet]] or [[urban network]]s, and [[super-spreader]]s of disease. Centrality concepts were first developed in [[social network analysis]], and many of the terms used to measure centrality reflect their [[sociology|sociological]] origin.&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
In graph theory and network analysis, indicators of centrality identify the most important vertices within a graph. Applications include identifying the most influential person(s) in a social network, key infrastructure nodes in the Internet or urban networks, and super-spreaders of disease. Centrality concepts were first developed in , and many of the terms used to measure centrality reflect their sociological origin.&lt;br /&gt;
&lt;br /&gt;
They should not be confused with [[node influence metric]]s, which seek to quantify the influence of every node in the network.&lt;br /&gt;
&lt;br /&gt;
They should not be confused with node influence metrics, which seek to quantify the influence of every node in the network.&lt;br /&gt;
&lt;br /&gt;
在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;图论 graph theory &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络分析 network analysis &amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性 centrality &amp;lt;/font&amp;gt;'''指标用于识别图中最重要的顶点。其应用包括在社会网络中识别出最有影响力的个人，在因特网或城市网络中识别出最为关键的基础设施节点，以及识别疾病的超级传播者。中心性的概念最初由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;社会网络分析 social network analysis&amp;lt;/font&amp;gt;'''所发展，因此许多用于衡量中心性的术语都反映出了它们的社会学出身。&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;中心性不应与节点影响度相混淆，后者意在量化网络中每个节点的影响。&lt;br /&gt;
&lt;br /&gt;
==中心性指数的定义与特性Definition and characterization of centrality indices==&lt;br /&gt;
&lt;br /&gt;
Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性指数 centrality indices&amp;lt;/font&amp;gt;'''旨在探寻如何描绘重要节点这一问题。这一问题的答案通常实值函数的形式给出，可根据函数值将图中各节点进行排序，进而确定最为重要的节点。&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
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The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
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“重要性”的含义十分广泛，因此导致了许多不同的中心性定义方式，我们可以将各种不同的定义方式划分为如下两类。&lt;br /&gt;
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&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important.&amp;lt;ref name=Borgatti2005/&amp;gt; &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt; Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important. &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&lt;br /&gt;
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“重要性”可以被设想为与网络中的某种流动或传输有关。&amp;lt;ref name=Borgatti2005/&amp;gt; “重要性”也可以被设想为与网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 内聚力 cohesiveness&amp;lt;/font&amp;gt;'''有关。这允许我们根据内聚力的不同测量方式对中心性予以分类。&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;这些方法将中心性划分于完全不同的类别中，也就是在一种类别中的中心性往往无法适用于其他类别。&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt; Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one ([[Centrality#Degree centrality|degree centrality]]) to infinite walks ([[Centrality#Eigenvector centrality|eigenvalue centrality]]).&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=&amp;quot;Benzi2013&amp;quot;&amp;gt;{{cite journal | last1=Benzi | first1=Michele | last2=Klymko| first2=Christine | year=2013 |title= A matrix analysis of different centrality measures |arxiv=1312.6722 | doi=10.1137/130950550 | volume=36 | issue=2 | journal=SIAM Journal on Matrix Analysis and Applications | pages=686–706}}&amp;lt;/ref&amp;gt; The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one (degree centrality) to infinite walks (eigenvalue centrality). The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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当根据内聚力方法对中心性进行分类时，很明显大多数中心性都将被划分于同一类别。起始于给定顶点的步数总和仅取决于步数的定义以及计数方式。这种分类方式的不足表现为它仅能较弱的描绘中心性特征，即按照一步步度（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性 degree centrality&amp;lt;/font&amp;gt;'''）到无穷步步长（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征向量中心性 eigenvalue centrality&amp;lt;/font&amp;gt;'''）的方式将中心性置于一种光谱状的分类中。对于采用类似方式定义的各种中心性的观察也表明了这些指数之间的高阶相关性。&lt;br /&gt;
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===Characterization by network flows==&lt;br /&gt;
==网络流特征==&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at once.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at oe.&lt;br /&gt;
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一个网络可以被看成是对某种物体流动的路径描述。使基于流的类型和由中心性编码的路径类型（同时）得到表征。一个流可以基于传输，每个不可分割的项目从一个节点到另一个节点，就像一个包裹从配送站送到客户的房子。第二种情况是串行复制，在这种情况下，一个项从源节点被复制到达目标节点。例如通过流言传播信息，以私有方式传播信息，并在流程结束时通知源节点和目标节点。最后一种情况是并行复制，即同时将项目复制到多个链接，就像无线电广播一次性向多个听众提供相同的信息。&lt;br /&gt;
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Likewise, the type of path can be constrained to [[Distance (graph theory)|geodesics]] (shortest paths), [[Glossary of graph theory terms#path|paths]]  (no vertex is visited more than once), [[Glossary of graph theory terms#trail|trails]] (vertices can be visited multiple times, no edge is traversed more than once), or [[Glossary of graph theory terms#walk|walks]] (vertices and edges can be visited/traversed multiple times).&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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Likewise, the type of path can be constrained to geodesics (shortest paths), paths  (no vertex is visited more than once), trails (vertices can be visited multiple times, no edge is traversed more than once), or walks (vertices and edges can be visited/traversed multiple times).&lt;br /&gt;
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同样，路径类型可以被限定为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Distance &amp;lt;/font&amp;gt;'''(最短路径)、路径(对顶点的访问不超过一次)、小径(可以访问多次顶点，没有边被访问超过一次)或者步子(可以访问/遍历多次顶点和边)。&lt;br /&gt;
===Characterization by walk structure===&lt;br /&gt;
==行走结构特征==&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either ''radial'' or ''medial.'' Radial centralities count walks which start/end from the given vertex. The [[Centrality#Degree centrality|degree]] and [[Centrality#Eigenvector centrality|eigenvalue]] centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's [[Centrality#Betweenness centrality|betweenness]] centrality, the number of shortest paths which pass through the given vertex.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either radial or medial. Radial centralities count walks which start/end from the given vertex. The degree and eigenvalue centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's betweenness centrality, the number of shortest paths which pass through the given vertex.&lt;br /&gt;
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可以从中心性的构造方式推导出另一种分类方法。这又分成了两个类。中心点可以是放射状的，也可以是内侧的。从给定顶点开始/结束的径向中心点数。度和特征值中心是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 径向中心Radial centralities&amp;lt;/font&amp;gt;'''的例子，计算长度为一或无穷大的行走的个数。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中间中心性Medial centralities&amp;lt;/font&amp;gt;'''计算通过给定顶点的步数。典型的例子是 弗里曼的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality,&amp;lt;/font&amp;gt;'''，即穿过给定顶点的最短路径的数量。&lt;br /&gt;
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Likewise, the counting can capture either the ''volume'' or the ''length'' of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's [[Centrality#Closeness centrality|closeness]] centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example.&amp;lt;ref name=Borgatti2006/&amp;gt; Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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Likewise, the counting can capture either the volume or the length of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's closeness centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example. Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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同样地，计数可以抓住行走的体积或长度。体积是给定类型的行走的总数。上一段的三个例子就属于这一类。长度则给出从给定顶点到图中其余顶点的距离。弗里曼 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，即从一个给定顶点到所有其他顶点的测地距离，是最著名的例子。请注意，这种分类独立于步行计数的类型(即：步行，小道，路径，测地线)。&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&lt;br /&gt;
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博尔加蒂和埃弗雷特提出，这种类型学为如何最好地比较中心性度量提出了建议。在这个22分类中，放在同一盒子中的中心点足够相似，可以做出合理的选择; 人们可以合理地比较哪个对于给定的应用更好。然而，不同盒子中的度量方法是截然不同的。只有在预先确定哪个类别更适用的情况下，对相对适应性的评估才会发生，这使得比较变得毫无意义。&lt;br /&gt;
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===Radial-volume centralities exist on a spectrum===&lt;br /&gt;
==光谱上存在的径向体积中心==&lt;br /&gt;
The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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步行结构的特征表明，几乎所有广泛使用的中心性都是径向体积的衡量。这得出结论顶点的中心性是与之相关联的顶点中心性的函数。中心性根据如何定义关联而不同。&lt;br /&gt;
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Bonacich showed that if association is defined in terms of [[Glossary of graph theory terms#walk|walks]], then a family of centralities can be defined based on the length of walk considered.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;/&amp;gt; [[Centrality#Degree centrality|Degree centrality]] counts walks of length one, while [[Centrality#Eigenvector centrality|eigenvalue centrality]] counts walks of length infinity. Alternative definitions of association are also reasonable. [[Alpha centrality]] allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich showed that if association is defined in terms of walks, then a family of centralities can be defined based on the length of walk considered. Degree centrality counts walks of length one, while eigenvalue centrality counts walks of length infinity. Alternative definitions of association are also reasonable. Alpha centrality allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich 指出，如果联想是根据行走来定义的，那么可以根据考虑的行走长度来定义一个中心性家族。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''计算长度为1的行走，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征值中心性Eigenvalue centrality  &amp;lt;/font&amp;gt;'''计算长度为无穷大的行走。关联的其他定义也是合理的。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 阿尔法中心性Alpha centrality&amp;lt;/font&amp;gt;'''允许顶点有一个外部影响源。埃斯特拉达的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图中心性Subgraph centrality &amp;lt;/font&amp;gt;'''提出只计算封闭路径(三角形、正方形等)。).&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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这些测量方法的核心是这种现象：图中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵&amp;lt;/font&amp;gt;'''的幂给出了由该幂给出的散步长度的数目。同样，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 矩阵指数Matrix exponential&amp;lt;/font&amp;gt;'''也与给定长度的行走次数密切相关。邻接矩阵的初始转换允许对步行计数的类型进行不同的定义。无论采用哪种方法，顶点的中心性都可以表示为无穷和&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum _ { k = 0} ^ infty a _ { r } ^ { k } beta ^ k &amp;lt;/math &amp;gt; &lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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矩阵能量或者&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum { k = 0} ^ infty frac {(a _ r beta) ^ k }{ k！{/math &amp;gt; &lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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对于矩阵指数函数，其中&lt;br /&gt;
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* &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; is walk length,&lt;br /&gt;
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* &amp;lt;math&amp;gt;A_R&amp;lt;/math&amp;gt; is the transformed adjacency matrix, and&lt;br /&gt;
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* &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; is a discount parameter which ensures convergence of the sum.&lt;br /&gt;
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K为步长，A_R是邻接矩阵的转秩，贝达是保证收敛的折扣参数。&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. [[Alpha centrality]] replaces the adjacency matrix with its [[resolvent formalism|resolvent]]. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to [[Centrality#Degree centrality|degree centrality]]. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to [[Centrality#Eigenvector centrality|eigenvalue centrality]].&amp;lt;ref name=Benzi2013/&amp;gt;&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. Alpha centrality replaces the adjacency matrix with its resolvent. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to degree centrality. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to eigenvalue centrality.&lt;br /&gt;
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博纳奇的一系列措施并没有改变邻接矩阵。阿尔法集中性用它的解决方案替代了邻接矩阵。子图集中性用它的踪迹取代了邻接矩阵。一个令人吃惊的结论是，不管邻接矩阵最初的转变是什么，所有这些方法都有共同的限制行为。随着贝塔系数趋近于零，指数收敛到度中心性。随着贝塔系数接近其最大值，指数收敛到特征值的中心性。&lt;br /&gt;
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===Game-theoretic centrality===&lt;br /&gt;
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=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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上述大多数标准措施的共同特点是，它们通过只关注一个节点本身所扮演的角色来评估确定节点的重要性。然而, 在许多应用中，这种方法是不充分的，因为可能会发生协同作用&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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如果将节点的功能分组考虑。&lt;br /&gt;
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[[File:Game-theoretic centrality.png|Example of game-theoretic centrality]]&lt;br /&gt;
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Example of game-theoretic centrality&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''的例子&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in &amp;lt;ref&amp;gt;Michalak, Aadithya, Szczepański, Ravindran, &amp;amp; Jennings {{ArXiv|1402.0567}}&amp;lt;/ref&amp;gt; uses the [[Shapley value]]. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in  uses the Shapley value. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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例如，考虑阻止流行病的问题。看看上面的网络图像，我们应该给哪些节点接种疫苗？基于前面描述的措施，我们希望识别在疾病传播中最重要的节点。仅仅基于中心的方法，即关注节点的个别特性，可能不是一个好主意。红色方块中的节点，单独不能阻止疾病的传播，但把它们作为一个群体来考虑，我们清楚地看到，如果疾病在节点 &amp;lt; math &amp;gt; v _ 1 &amp;lt;/math &amp;gt; 、 &amp;lt; math &amp;gt; v _ 4 &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; v _ 5 &amp;lt;/math &amp;gt; 中开始，它们就能阻止疾病的传播。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''试图利用博弈论中的工具来研究所描述的问题和机会。本文提出的方法使用了 Shapley 值。由于 Shapley 值计算的时间复杂性，这一领域的大部分工作都集中在实现新的算法和方法，这些算法和方法依赖于网络的特殊拓扑结构或问题的特殊性质。这种方法可以将时间复杂度从指数级降低到多项式级。&lt;br /&gt;
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Similarly, the solution concept [[authority distribution]] (&amp;lt;ref&amp;gt;{{cite journal |last=Hu |first=Xingwei |first2=Lloyd |last2=Shapley |title=On Authority Distributions in Organizations |journal=Games and Economic Behavior |volume=45 |pages=132–170 |year=2003 | doi = 10.1016/s0899-8256(03)00130-1 }}&amp;lt;/ref&amp;gt;) applies the [[Shapley-Shubik power index]], rather than the [[Shapley value]], to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020)&amp;lt;ref&amp;gt;{{cite journal|last=Hu|first=Xingwei|year=2020|volume=7|title=Sorting big data by revealed preference with application to college ranking |journal=Journal of Big Data|doi=10.1186/s40537-020-00300-1|doi-access=free}}&amp;lt;/ref&amp;gt;, such as ranking U.S. colleges.&lt;br /&gt;
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Similarly, the solution concept authority distribution () applies the Shapley-Shubik power index, rather than the Shapley value, to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020), such as ranking U.S. colleges.&lt;br /&gt;
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同样，'''&amp;lt;font color=&amp;quot;#CD32CD&amp;quot;&amp;gt; 加权分布概念的解()The solution concept authority distribution () &amp;lt;/font&amp;gt;'''采用 Shapley-Shubik 幂指数，而不是 Shapley 值来衡量双方之间的直接影响。这种分布确实是一种产生'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征向量中心性Engenvector centrality&amp;lt;/font&amp;gt;'''的类型。它用于对 Hu (2020)中的大数据对象进行排序，比如美国大学排名。&lt;br /&gt;
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== Important limitations ==&lt;br /&gt;
==重要限制==&lt;br /&gt;
Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the [[Krackhardt kite graph]], for which three different notions of centrality give three different choices of the most central vertex.&amp;lt;ref&amp;gt;{{cite journal|title=Assessing the Political Landscape: Structure, Cognition, and Power in Organizations|first=David|last=Krackhardt|authorlink=David Krackhardt|journal=Administrative Science Quarterly|volume=35|issue=2|date=June 1990|pages=342–369|doi=10.2307/2393394|jstor=2393394}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the Krackhardt kite graph, for which three different notions of centrality give three different choices of the most central vertex.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中心性Centrality&amp;lt;/font&amp;gt;'''指标有两个重要的局限性，一个显而易见，另一个则不易察觉。显而易见的局限性是，对于一个应用最优的中心性对于另一个应用常常是次优的。事实上，如果不是这样，我们就不需要这么多不同的中心性。克拉克哈特风筝图为这一现象提供了一个例证，对于这个图，三个不同的中心性概念给出了三个最中心顶点的不同选择。&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices.&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=Borgatti2005/&amp;gt; This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  [[node influence metric]]s to address this problem.&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices. This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  node influence metrics to address this problem.&lt;br /&gt;
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更不易察觉的限制是通常会错误地认为顶点中心性表示顶点的相对重要性。中心性指数被明确地设计来产生一个指出最重要顶点的排名。在刚才提到的限制下，他们做得很好。它们通常不用来测量节点的影响力。最近，网络物理学家开始开发'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;节点影响度量Node influence metrics &amp;lt;/font&amp;gt;'''来解决这个问题。&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying [[Centrality#Freeman centralization|Freeman centralization]] to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt; This approach, however, is seldom seen in practice.{{citation needed|reason=I've come across quite some theoretical studies that indicate otherwise. My suggestion is to remove this sentence, if reasonable citation is not provided.|date=September 2015}}&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying Freeman centralization to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores. This approach, however, is seldom seen in practice.&lt;br /&gt;
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错误有两方面。首先，一个排名只根据顶点的重要性排序，它并不对节点重要性的不同水平进行量化区分。这可以通过将 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;'''应用到中心性度量来缓解，这种度量可以根据节点的不同中心性得分来判断节点的重要性。此外， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;''使人们能够通过比较几个网络的最高中心性得分来比较它们。然而，这种方法在实践中很少见到。&lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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其次，用以(正确地)识别给定网络/应用中最重要顶点的特征并不一定可推广到其余顶点。&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot; /&amp;gt;&amp;lt;ref name=&amp;quot;daSilva2012&amp;quot;&amp;gt;{{cite journal | last1=da Silva|first1=Renato |last2=Viana|first2=Matheus|last3=da F. Costa |first3=Luciano| title=Predicting epidemic outbreak from individual features of the spreaders| journal=J. Stat. Mech.: Theory Exp. | year=2012|volume=2012|pages=P07005|number=7 | doi=10.1088/1742-5468/2012/07/p07005|arxiv=1202.0024|bibcode=2012JSMTE..07..005A}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Bauer2012&amp;quot;&amp;gt;{{cite journal | last1=Bauer|first1=Frank | last2=Lizier|first2=Joseph|title=Identifying influential spreaders and efficiently estimating infection numbers in epidemic models: A walk counting approach| journal=Europhys Lett | year=2012| volume=99| pages=68007|number=6 | doi=10.1209/0295-5075/99/68007|arxiv=1203.0502|bibcode=2012EL.....9968007B}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Sikic2013&amp;quot;&amp;gt;{{ cite journal| last1= Sikic| first1=Mile|last2=Lancic|first2=Alen|last3=Antulov-Fantulin|first3=Nino|last4=Stefanic|first4=Hrvoje| title = Epidemic centrality -- is there an underestimated epidemic impact of network peripheral nodes? |journal = The European Physical Journal B |volume=86 |number=10 |pages=1–13 |year=2013 | doi=10.1140/epjb/e2013-31025-5|arxiv=1110.2558 | bibcode=2013EPJB...86..440S}}&amp;lt;/ref&amp;gt; This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&amp;lt;ref name=&amp;quot;Ghoshal2011&amp;quot;&amp;gt;{{cite journal | last1=Ghoshal | first1= G. | last2= Barabsi |first2= A L | title = Ranking stability and super-stable nodes in complex networks. | journal = Nat Commun | volume =2 | page = 394| year= 2011 | doi=10.1038/ncomms1396 | pmid= 21772265 | bibcode=2011NatCo...2..394G | doi-access= free }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless. This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&lt;br /&gt;
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对于大多数其他网络节点，排名可能是没有意义的。这就解释了为什么，例如，只有谷歌图片搜索的前几个结果以合理的顺序出现。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页排名Pagerank&amp;lt;/font&amp;gt;'''是一个非常不稳定的度量，显示了在跳转参数小的调整之后频繁的秩逆转。&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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虽然中心性指数未能推广到网络的其他部分，乍看起来似乎是违反直觉的，但它直接遵循上述定义。&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot;&amp;gt;{{cite journal |last1= Lawyer |first1= Glenn |year= 2015 |title= Understanding the spreading power of all nodes in a network: a continuous-time perspective |journal=Sci Rep |volume=5|pages=8665|doi=10.1038/srep08665 |pmid=25727453 |pmc=4345333|arxiv=1405.6707|bibcode=2015NatSR...5E8665L}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&lt;br /&gt;
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复杂网络具有异构的拓扑结构。由于最佳度量取决于最重要顶点的网络结构，对于这些顶点最优的度量对于网络的其余部分是次优的。&lt;br /&gt;
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==Degree centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Degree (graph theory)}} &lt;br /&gt;
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[[File:6 centrality measures.png|thumb|right|300px|Examples of A) [[Betweenness centrality]], B) [[Closeness centrality]], C) [[Eigenvector centrality]], D) [[Degree centrality]], E) [[Centrality#Harmonic centrality|Harmonic centrality]] and F) [[Katz centrality]] of the same graph.]]&lt;br /&gt;
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Examples of A) [[Betweenness centrality, B) Closeness centrality, C) Eigenvector centrality, D) Degree centrality, E) Harmonic centrality and F) Katz centrality of the same graph.]]&lt;br /&gt;
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实例 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; a)[中介中心性A) [[Betweenness centrality,b)紧密中心性，B) Closeness centrality, c)特征向量中心性，C) Eigenvector centrality, d)度中心性，D) Degree centrality, e)调和中心性，E) Harmonic centrality andf) 卡兹Katz 中心性]F) Katz centrality .]]&amp;lt;/font&amp;gt;'''&lt;br /&gt;
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Historically first and conceptually simplest is '''degree centrality''', which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely [[indegree]] and [[outdegree]]. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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Historically first and conceptually simplest is degree centrality, which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely indegree and outdegree. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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历史上最简单的概念是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''，它定义为一个节点上发生的链接数量(即一个节点拥有的关系数量)。度可以根据节点捕获流经网络的任何东西(例如病毒或某些信息)的直接风险来解释。在有向网络的情况下(其中联系有方向) ，我们通常定义两个独立的度量，即 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度 Outdegree&amp;lt;/font&amp;gt;'''。因此，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度indegree&amp;lt;/font&amp;gt;'''是指向该节点的关系数，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度outdegree&amp;lt;/font&amp;gt;'''是指该节点指向其他节点的关系数。当关系与一些积极的方面如友谊或合作有关时， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''通常被解释为一种形式的受欢迎，而 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度Indegree&amp;lt;/font&amp;gt;'''则被解释为合群。&lt;br /&gt;
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The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
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The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
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对于给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边，度的中心性定义为&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&lt;br /&gt;
Calculating degree centrality for all the nodes in a graph takes [[big theta|&amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt;]] in a [[dense matrix|dense]] [[adjacency matrix]] representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a [[sparse matrix]] representation.&lt;br /&gt;
&lt;br /&gt;
Calculating degree centrality for all the nodes in a graph takes &amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt; in a dense adjacency matrix representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a sparse matrix representation.&lt;br /&gt;
&lt;br /&gt;
计算一个图中所有节点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''需要在图的稠密'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵Adjacency matrix &amp;lt;/font&amp;gt;'''表示中使用 Theta (v ^ 2) &amp;lt;/math &amp;gt; ，而在稀疏矩阵表示中使用 Theta (e) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of ''graph centralization''.&amp;lt;ref&amp;gt;Freeman, Linton C. &amp;quot;Centrality in social networks conceptual clarification.&amp;quot; Social networks 1.3 (1979): 215–239.&amp;lt;/ref&amp;gt; Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
&lt;br /&gt;
The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of graph centralization. Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
&lt;br /&gt;
节点级中心性的定义可以扩展到整个图，在这种情况下，我们指的是图的集中性。设 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 为 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''最高的节点。让 &amp;lt; math &amp;gt; x: = (y，z) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; | y | &amp;lt;/math &amp;gt; 节点连接图，最大化下列数量(&amp;lt; math &amp;gt; y * &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 中度最高的节点) :&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h = sum ^ { | y | }{ j = 1}[ c _ d (y *)-c _ d (y _ j)] &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
&lt;br /&gt;
Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
&lt;br /&gt;
相应地，图形 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''如下:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ h } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a [[star graph]]), and in this case&lt;br /&gt;
&lt;br /&gt;
The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a star graph), and in this case&lt;br /&gt;
&lt;br /&gt;
当图形 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 包含一个所有其他节点都连接的中心节点(一个星形图)时，&amp;lt; math &amp;gt; h &amp;lt;/math &amp;gt; 的值最大化，在这种情况下&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
(n-1)-1) = n ^ 2-3n + 2&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
所以，对于任意的图 &amp;lt; math &amp;gt; g: = (v，e) ，&amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ | v | ^ 2-3 | v | + 2} &amp;lt;/math &amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Closeness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Closeness centrality}}In a [[Connected component (graph theory)|connected]] [[Graph (discrete mathematics)|graph]], the [[Normalization (statistics)|normalized]] '''closeness centrality''' (or '''closeness''') of a node is the average length of the [[Shortest path problem|shortest path]] between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
&lt;br /&gt;
In a connected graph, the normalized closeness centrality (or closeness) of a node is the average length of the shortest path between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
&lt;br /&gt;
在连通图中，节点的标准'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''(或贴近性)是节点与图中所有其他节点之间最短路径的平均长度。因此，一个节点越是中心，它就越接近所有其他节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Closeness was defined by [[Alex Bavelas]] (1950) as the [[Multiplicative inverse|reciprocal]] of the '''farness''',&amp;lt;ref&amp;gt;Alex Bavelas. Communication patterns in task-oriented groups. ''J. Acoust. Soc. Am'', '''22'''(6):725–730, 1950.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;{{cite journal|year=1966|title=The centrality index of a graph|url=|journal=Psychometrika|volume=31|issue=4|pages=581–603|doi=10.1007/bf02289527|pmid=5232444|hdl=10338.dmlcz/101401|last1=Sabidussi|first1=G|hdl-access=free}}&amp;lt;/ref&amp;gt; that is:&lt;br /&gt;
&lt;br /&gt;
Closeness was defined by Alex Bavelas (1950) as the reciprocal of the farness, that is:&lt;br /&gt;
&lt;br /&gt;
亚历克斯 · 巴维拉斯(1950)将亲密度定义为相对于距离的倒数，即:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
C (x) = frac {1}{ sum _ y d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the [[Distance (graph theory)|distance]] between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the distance between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; d (y，x) &amp;lt;/math &amp;gt; 是顶点 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; 之间的距离。然而，当谈到'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''时，人们通常会提到它的标准化形式，一般是以前的公式乘以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; ，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。这种调整允许比较不同大小图形的节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Taking distances ''from'' or ''to'' all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in [[directed graph]]s (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
&lt;br /&gt;
Taking distances from or to all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in directed graphs (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
&lt;br /&gt;
从所有其他节点或到所有其他节点的距离在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 无向图Undirected graphs&amp;lt;/font&amp;gt;'''中是不相关的，但是在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 有向图Directed graphs&amp;lt;/font&amp;gt;'''中可能产生完全不同的结果(例如:一个网站可以从传出链接获得高的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，而从传入链接获得低的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''）。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
===Harmonic centrality===&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the '''harmonic centrality''' reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the harmonic centrality reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
在一个(不一定是连通的)图中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''反转了'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''定义中的和互反运算:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h (x) = sum { y neq x } frac {1}{ d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; 1/d (y，x) = 0 &amp;lt;/math &amp;gt; if there is no path from &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; to &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 。调和中心性可以通过除以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; 来标准化，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Harmonic centrality was proposed by [[Massimo Marchiori|Marchiori]] and [[Vito Latora|Latora]] (2000)&amp;lt;ref name=&amp;quot;marchiorilatora2000&amp;quot;&amp;gt;{{citation| journal = Physica A: Statistical Mechanics and Its Applications  | last1 = Marchiori | first1 = Massimo | last2 = Latora | first2 = Vito | year = 2000 | volume = 285 | issue = 3–4 | pages = 539–546 | title = Harmony in the small-world | doi=10.1016/s0378-4371(00)00311-3| arxiv = cond-mat/0008357 | bibcode = 2000PhyA..285..539M }}&amp;lt;/ref&amp;gt; and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot;&amp;lt;ref&amp;gt;{{cite journal|first1=Anthony|last1=Dekker|title=Conceptual Distance in Social Network Analysis|journal=Journal of Social Structure|volume=6|issue=3|year=2005|url=http://www.cmu.edu/joss/content/articles/volume6/dekker/index.html}}&amp;lt;/ref&amp;gt; and by Rochat (2009).&amp;lt;ref&amp;gt;{{cite conference  | author = Yannick Rochat  | title = Closeness centrality extended to unconnected graphs: The harmonic centrality index | conference = Applications of Social Network Analysis, ASNA 2009 | url = http://infoscience.epfl.ch/record/200525/files/%5bEN%5dASNA09.pdf }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Harmonic centrality was proposed by Marchiori and Latora (2000) and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot; and by Rochat (2009).&lt;br /&gt;
&lt;br /&gt;
调和中心性是由 Marchiori 和 Latora (2000)提出的，然后是 Dekker (2005)独立提出的，使用的名称是“有价值的中心性” ，Rochat (2009)。&lt;br /&gt;
&lt;br /&gt;
==Betweenness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Betweenness centrality}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Graph betweenness.svg|240px|right|thumb|Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.]]&lt;br /&gt;
&lt;br /&gt;
Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.&lt;br /&gt;
&lt;br /&gt;
色调(从红色 = 0到蓝色 = max)表示节点之间的距离。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
'''Betweenness''' is a centrality measure of a [[vertex (graph theory)|vertex]] within a [[Graph (discrete mathematics)|graph]] (there is also [[edge (graph theory)|edge]] betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by [[Linton Freeman]]&amp;lt;ref name=&amp;quot;freeman1977&amp;quot;&amp;gt;{{cite journal |last1 = Freeman |first1 = Linton | year=1977| title = A set of measures of centrality based upon betweenness | journal = Sociometry| volume=40|issue = 1 | pages=35–41 | doi=10.2307/3033543|jstor = 3033543 }}&amp;lt;/ref&amp;gt; In his conception, vertices that have a high probability to occur on a randomly chosen [[shortest path problem|shortest path]] between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
&lt;br /&gt;
Betweenness is a centrality measure of a vertex within a graph (there is also edge betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by Linton Freeman In his conception, vertices that have a high probability to occur on a randomly chosen shortest path between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
&lt;br /&gt;
中介性是图中顶点的中心性度量(也有边中介性，这里没有讨论)。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''量化了一个节点沿着其他两个节点之间的最短路径充当桥梁的次数。在林顿 · 弗里曼的概念中，在两个随机选择的顶点之间随机选择的最短路径上出现概率高的顶点具有很高的中介性。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
&lt;br /&gt;
The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
&lt;br /&gt;
在一个图 &amp;lt; math &amp;gt; g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的顶点之间的距离计算如下:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
# For each pair of vertices (''s'',''t''), compute the [[Shortest path problem|shortest paths]] between them.&lt;br /&gt;
&lt;br /&gt;
 For each pair of vertices (s,t), compute the shortest paths between them.&lt;br /&gt;
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对于每一对顶点(s，t) ，计算它们之间的最短路径。&lt;br /&gt;
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# For each pair of vertices (''s'',''t''), determine the fraction of shortest paths that pass through the vertex in question (here, vertex ''v'').&lt;br /&gt;
&lt;br /&gt;
 For each pair of vertices (s,t), determine the fraction of shortest paths that pass through the vertex in question (here, vertex v).&lt;br /&gt;
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对于每对顶点(s，t) ，确定通过该顶点(这里是顶点 v)的最短路径的分数。&lt;br /&gt;
&lt;br /&gt;
# Sum this fraction over all pairs of vertices (''s'',''t'').&lt;br /&gt;
&lt;br /&gt;
 Sum this fraction over all pairs of vertices (s,t).&lt;br /&gt;
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对所有顶点对(s，t)求这个分数的和。&lt;br /&gt;
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More compactly the betweenness can be represented as:&amp;lt;ref name=&amp;quot;brandes&amp;quot;&amp;gt;{{cite journal |last1 = Brandes |first1 = Ulrik | year=2001 |title = A faster algorithm for betweenness centrality  | journal = Journal of Mathematical Sociology| volume=25|issue = 2 | pages=163–177| url = http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.11.2024 | accessdate = October 11, 2011| format = PDF | doi=10.1080/0022250x.2001.9990249|citeseerx = 10.1.1.11.2024 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
More compactly the betweenness can be represented as:&lt;br /&gt;
&lt;br /&gt;
更确切地说，两者之间的关系可以表示为:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
{ math &amp;gt; c _ b (v) = sum _ { s neq v neq t in v } frac { sigma _ st }(v)}{ sigma _ st } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including ''v'', which for [[Digraph (mathematics)|directed graphs]] is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected [[Star (graph theory)|star graph]], the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including v, which for directed graphs is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected star graph, the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; sigma { st } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { st }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径数。有向图是 &amp;lt; math &amp;gt; (n-1)(n-2) &amp;lt;/math &amp;gt; ，无向图是 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; 。例如，在一个无向星图中，中心顶点(包含在每个可能的最短路径中)的中介性为 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; (1，如果标准化) ，而叶子(包含在没有最短路径中)的中介性为0。&lt;br /&gt;
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&lt;br /&gt;
&lt;br /&gt;
From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires [[Big O notation|&amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt;]] time with the [[Floyd–Warshall algorithm]]. However, on sparse graphs, [[Johnson's algorithm]] may be more efficient, taking [[Big O notation|&amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt;]] time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm&amp;lt;ref name=brandes/&amp;gt; which takes [[Big O notation|&amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt;]] time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&amp;lt;ref name=&amp;quot;brandes&amp;quot; /&amp;gt;&lt;br /&gt;
&lt;br /&gt;
From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires &amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt; time with the Floyd–Warshall algorithm. However, on sparse graphs, Johnson's algorithm may be more efficient, taking &amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt; time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm which takes &amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt; time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&lt;br /&gt;
&lt;br /&gt;
从计算的角度来看，图中所有顶点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介和紧密中心性Betweenness and Closeness centralities&amp;lt;/font&amp;gt;'''都涉及到计算图中所有顶点对之间的最短路径，这就需要用 Floyd-Warshall 算法计算时间。然而，对于稀疏图，约翰逊算法的效率可能更高，采用 &amp;lt; math &amp;gt; o (v ^ 2 log v + v e) &amp;lt;/math &amp;gt; 时间。在不加权图的情况下，可以用 Brandes 的算法进行计算，该算法需要 &amp;lt; math &amp;gt; o (v e) &amp;lt;/math &amp;gt; 时间。一般情况下，这些算法假定图是无向的，并且连通图中允许有圈和多条边。当专门处理网络图时，图通常没有环或多条边来维持简单的关系(其中的边表示两个人或顶点之间的联系)。在这种情况下，使用 Brandes 的算法将最终的中心性分数除以2来计算每条被重复计算的最短路径。&lt;br /&gt;
&lt;br /&gt;
==Eigenvector centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Eigenvector centrality}}&lt;br /&gt;
&lt;br /&gt;
'''Eigenvector centrality''' (also called '''eigencentrality''') is a measure of the influence of a [[node (networking)|node]] in a [[network (mathematics)|network]]. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&amp;lt;ref&amp;gt;{{cite journal|title = The mathematics of networks|url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf|author = M. E. J. Newman|accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;/&amp;gt; [[Google]]'s [[PageRank]] and the [[Katz centrality]] are variants of the eigenvector centrality.&amp;lt;ref name=&amp;quot;ams&amp;quot;&amp;gt;{{Cite web | url=http://www.ams.org/samplings/feature-column/fcarc-pagerank | title=American Mathematical Society}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Eigenvector centrality (also called eigencentrality) is a measure of the influence of a node in a network. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''(也称为特征中心性)是衡量网络中节点影响的一个指标。它将相对得分分配给网络中的所有节点，这是基于这样一个概念: 与得分较高的节点相比，与得分较低的节点相同的连接对所涉及的节点的得分贡献更大。&lt;br /&gt;
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=== Using the adjacency matrix to find eigenvector centrality ==&lt;br /&gt;
==使用'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''发现'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the [[adjacency matrix]], i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
&lt;br /&gt;
For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the adjacency matrix, i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
&lt;br /&gt;
对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 让 &amp;lt; math &amp;gt; a = (a { v，t }) &amp;lt;/math &amp;gt; 成为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''，即。如果顶点 &amp;lt; math &amp;gt; &amp;gt; v &amp;lt;/math &amp;gt; 与 math &amp;gt; t &amp;lt;/math &amp;gt; 相连，而 &amp;lt; math &amp;gt; a { v，t } = 0 &amp;lt;/math &amp;gt; 否则。顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分可以定义为:&lt;br /&gt;
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&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
在 m (v)} x _ t = frac {1}{ lambda } sum { t in g } a { v，t } x _ t &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the [[eigenvector]] equation&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the eigenvector equation&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; m (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 和 &amp;lt; math &amp;gt; &amp;gt; lambda &amp;lt;/math &amp;gt; 的邻居集合。通过一个小的重新排列，这可以被重写成向量符号，作为特征向量方程&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[ math &amp;gt; mathbf { Ax } = { lambda } mathbf { x } &amp;lt;/math &amp;gt; &lt;br /&gt;
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In general, there will be many different [[eigenvalue]]s &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the [[Perron–Frobenius theorem]]. This greatest eigenvalue results in the desired centrality measure.&amp;lt;ref&amp;gt;{{cite journal  | author = M. E. J. Newman  | title = The mathematics of networks  | url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf  | accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt; The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices ''n''. [[Power iteration]] is one of many [[eigenvalue algorithm]]s that may be used to find this dominant eigenvector.&amp;lt;ref name=&amp;quot;ams&amp;quot; /&amp;gt; Furthermore, this can be generalized so that the entries in ''A'' can be real numbers representing connection strengths, as in a [[stochastic matrix]].&lt;br /&gt;
&lt;br /&gt;
In general, there will be many different eigenvalues &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the Perron–Frobenius theorem. This greatest eigenvalue results in the desired centrality measure. The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices n. Power iteration is one of many eigenvalue algorithms that may be used to find this dominant eigenvector. Furthermore, this can be generalized so that the entries in A can be real numbers representing connection strengths, as in a stochastic matrix.&lt;br /&gt;
&lt;br /&gt;
一般情况下，存在许多不同的特征值，对于这些特征值存在一个非零特征向量解。由于邻接矩阵中的条目是非负的，所以由 Perron-弗罗贝尼乌斯定理得出，它有一个实的和正的唯一最大特征值。由这个最大的特征值得出期望的中心性度量。相关特征向量的 &amp;lt; math &amp;gt; v ^ { th } &amp;lt;/math &amp;gt; 分量给出了网络中顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分。特征向量只定义了一个公共因子，所以只有顶点中心的比例是明确定义的。要定义一个绝对分数，必须对特征向量进行标准化，例如，使所有顶点的和为1或顶点的总数n。此外，这可以通用，使得 a 中的条目可以是表示连接强度的真实数字，就像'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 随机矩阵Stochastic matrix&amp;lt;/font&amp;gt;'''中一样。&lt;br /&gt;
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==Katz centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Katz centrality}}&lt;br /&gt;
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'''Katz centrality'''&amp;lt;ref&amp;gt;Katz, L. 1953. A New Status Index Derived from Sociometric Index. Psychometrika, 39–43.&amp;lt;/ref&amp;gt; is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
Katz centrality is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''是度中心性的推广。度中心性度量的是直接邻居的数量，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''度量的是通过一条路径可以连接的所有节点的数量，而远处节点的贡献会受到'''&amp;lt;font color=&amp;quot;#32CD32&amp;quot;&amp;gt; '削弱（惩罚？）Penalized&amp;lt;/font&amp;gt;''。在数学上，它被定义为&lt;br /&gt;
&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[数学][数学]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; (0,1) &amp;lt;/math &amp;gt; 中的衰减因子。&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''可以看作是特征向量中心性的变体。Katz 中心性的另一种形式是&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
(x _ j + 1) &lt;br /&gt;
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Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
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Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
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与特征向量中心性的表达式相比，&amp;lt; math &amp;gt; x _ j &amp;lt;/math &amp;gt; 被 &amp;lt; math &amp;gt; x _ j + 1所代替&lt;br /&gt;
&lt;br /&gt;
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It is shown that&amp;lt;ref&amp;gt;{{cite journal | last1 = Bonacich | first1 = P | year = 1991 | title = Simultaneous group and individual centralities | url = | journal = Social Networks | volume = 13 | issue = 2| pages = 155–168 | doi=10.1016/0378-8733(91)90018-o}}&amp;lt;/ref&amp;gt; the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
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It is shown that the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
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结果表明，主特征向量(与 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; ，邻接矩阵的最大特征值相关)是 Katz 中心性的极限，因为 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 接近 &amp;lt; math &amp;gt; tfrac {1}{ lambda } &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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== PageRank centrality ==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页分布中心性PageRank&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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{{main|PageRank}}'''[[PageRank]]''' satisfies the following equation&lt;br /&gt;
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PageRank satisfies the following equation&lt;br /&gt;
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PageRank满足下面的等式&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
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1-alpha { n } ，&amp;lt;/math &amp;gt; &lt;br /&gt;
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&lt;br /&gt;
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where&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
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其中&lt;br /&gt;
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&lt;br /&gt;
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:&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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[ math &amp;gt; l (j) = sum { i } a { ji } &amp;lt;/math &amp;gt; &lt;br /&gt;
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is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&amp;lt;ref&amp;gt;[http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf How does Google rank webpages?] {{webarchive | url= https://web.archive.org/web/20120131083328/http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf |date=January 31, 2012 }} 20Q: About Networked Life&amp;lt;/ref&amp;gt;&lt;br /&gt;
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is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&lt;br /&gt;
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是节点 &amp;lt; math &amp;gt; j &amp;lt;/math &amp;gt; (或有向图中出站链接的数量)的邻居数量。与特征向量中心性和 Katz 中心性相比，尺度因子 &amp;lt; math &amp;gt; l (j) &amp;lt;/math &amp;gt; 是一个主要的区别。PageRank 和特征向量中心性的另一个区别是 PageRank 向量是一个左手特征向量(注意因子 &amp;lt; math &amp;gt; a _ { ji } &amp;lt;/math &amp;gt; 具有相反的索引)。&lt;br /&gt;
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==Percolation centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&amp;lt;ref name=&amp;quot;piraveenan2013&amp;quot;&amp;gt;{{cite journal |last1 = Piraveenan |first1 = M. |last2 = Prokopenko |first2 = M.|last3 = Hossain|first3 = L. |year=2013| title = Percolation Centrality: Quantifying Graph-Theoretic Impact of Nodes during Percolation in Networks | journal = PLOS One | volume=8 | issue=1 | doi=10.1371/journal.pone.0053095 | pages=e53095 | pmid=23349699 | pmc=3551907| bibcode=2013PLoSO...853095P }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&lt;br /&gt;
&lt;br /&gt;
在复杂网络中，存在大量的中心性度量来确定单个节点的“重要性”。然而，这些度量单纯从拓扑学的角度来量化节点的重要性，节点的值并不以任何方式依赖于节点的状态。不管网络动态如何，它都保持不变。即使对于加权的两者之间的度量也是如此。然而，一个节点可能很好地位于'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''或其他中心性度量的中心位置，但可能不是位于有过滤的网络的上下文中的中心位置。在许多情况下，复杂网络中都会出现“传染”现象。例如，病毒或细菌感染可以通过人们的社交网络传播，也就是所谓的接触网络。还可以在更高的抽象层次上考虑疾病的传播问题，设想通过公路、铁路或空中连接起来的城镇或人口中心网络。计算机病毒可以通过计算机网络传播。关于商业活动和交易的谣言或新闻也可以通过人们的社交网络传播。在所有这些情况下，一种“传染病”在一个复杂网络的链接上传播，随着它的传播，无论是可恢复的还是不可恢复的，都会改变节点的“状态”。例如，在流行病学方案中，随着感染扩散，个人从”易感”状态转变为”受感染”状态。在上面的例子中，随着传染的扩散，每个节点可以采取的状态可以是二进制的(例如接收/没有接收到一条新闻)、离散的(易感/受感染/康复) ，甚至是连续的(例如一个城镇中受感染的人的比例) 。这些情景的共同特点是，传染的扩散导致网络中节点状态的改变。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''（PC)就是基于这个思想而提出的，它特别地衡量了节点在协助网络渗滤方面的重要性。这项措施是由 piraveanan 等人提出的。&lt;br /&gt;
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'''Percolation centrality''' is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
&lt;br /&gt;
Percolation centrality is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''定义为在给定时间内一个给定节点的过滤路径的比例。“渗滤路径”是一对节点之间的最短路径，其中源节点被渗滤(例如，被感染)。目标节点可以是过滤的或非过滤的，或处于部分过滤状态。&lt;br /&gt;
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&lt;br /&gt;
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:&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; PC ^ t (v) = frac {1}{ N-2} sum { s neq v neq r } frac { sigma { sr }(v)}{ sigma { sr }} frac { x ^ t }{ sum {[{ x ^ t } i }}}]}}-{ x ^ t }{ v } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; σ { sr } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; r &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { sr }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径的总数。在时间 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 时，节点的过滤状态用 &amp;lt; math &amp;gt; { x ^ t } _ i &amp;lt;/math &amp;gt; 表示，两个特殊情况是当 &amp;lt; math &amp;gt; { x ^ t } _ i = 0 &amp;lt;/math &amp;gt; 表示在时间上是非过滤状态，而当 &amp;lt; math &amp;gt; &amp;lt; x ^ t &amp;lt;/math &amp;gt; i = 1 &amp;lt;/math &amp;gt; 表示在时间上是完全过滤状态。两者之间的值表示部分过滤状态(例如，在一个城镇网络中，这是该城镇感染者的百分比)。&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in [[Big O notation|&amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt;]] time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is [[Big O notation|&amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;]].&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in &amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt; time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is &amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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渗流路径的权重取决于分配给源节点的渗流水平，前提是源节点的渗流水平越高，源节点的路径就越重要。因此，位于源自高渗滤节点的最短路径上的节点可能对渗滤更为重要。PC 的定义也可以扩展到包括目标节点的权重。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''计算运行在 &amp;lt; math &amp;gt; o (NM) &amp;lt;/math &amp;gt; 时间，采用了 Brandes 快速算法的有效实现，如果计算需要考虑目标节点的权重，最坏情况下时间为 &amp;lt; math &amp;gt; o (n ^ 3) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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==Cross-clique centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 交叉团中心性Cross-clique centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
'''Cross-clique centrality''' of a single node in a complex graph determines the connectivity of a node to different [[clique (graph theory)|clique]]s. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in &amp;lt;ref name=&amp;quot;xssworms&amp;quot;&amp;gt;{{cite journal |last1 = Faghani|first1 = Mohamamd Reza| year=2013| title = A Study of XSS Worm Propagation and Detection Mechanisms in Online Social Networks | journal = IEEE Transactions on Information Forensics and Security|volume = 8|issue = 11|pages = 1815–1826|doi = 10.1109/TIFS.2013.2280884}}&amp;lt;/ref&amp;gt; but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
&lt;br /&gt;
Cross-clique centrality of a single node in a complex graph determines the connectivity of a node to different cliques. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in  but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
&lt;br /&gt;
复杂图中单个节点的跨团中心性决定了一个节点与不同团的连通性。具有高度跨团连通性的节点有利于信息或疾病在图中的传播。团是一种'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图Subgraphs&amp;lt;/font&amp;gt;'''，团中的每个节点都与团中的其他节点相连。对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边的交叉团连通性，定义为 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; x (v) &amp;lt;/math &amp;gt; 其中 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 所属的顶点团数。这个测度应用日久，但是在1998年由 Everett 和 Borgatti 首次提出，他们称之为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 派系重叠中心性Clique-overlap centrality&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
&lt;br /&gt;
==Freeman centralization==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心度Freeman centralization&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
The '''centralization''' of any network is a measure of how central its most central node is in relation to how central all the other nodes are.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;&amp;gt;{{citation | journal = Social Networks | last1 = Freeman | first1 = Linton C. | year = 1979 | volume = 1 | issue = 3 | pages = 215–239 | title = centrality in social networks: Conceptual clarification | url = http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | doi = 10.1016/0378-8733(78)90021-7 | citeseerx = 10.1.1.227.9549 | access-date = 2014-07-31 | archive-url = https://web.archive.org/web/20160222033108/http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | archive-date = 2016-02-22 | url-status = dead }}&amp;lt;/ref&amp;gt; Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
&lt;br /&gt;
The centralization of any network is a measure of how central its most central node is in relation to how central all the other nodes are. Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
&lt;br /&gt;
任何网络的集中度都是衡量其最核心的节点相对于其他所有节点的集聚程度的标准。集中度的度量方法是: (a)计算网络中最中心的节点与所有其他节点之间的中心性差异之和; (b)将这个数量除以理论上相同规模的任何网络中这种差异之和的最大值。因此，每个中心性度量都可以有自己的集中性度量。正式定义，如果 &amp;lt; math &amp;gt; c _ x (p _ i) &amp;lt;/math &amp;gt; 是点 &amp;lt; math &amp;gt; i &amp;lt;/math &amp;gt; 的中心性度量，如果 &amp;lt; math &amp;gt; c _ x (p _ *) &amp;lt;/math &amp;gt; 是网络中最大的中心性度量，如果:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; max sum { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i) &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&lt;br /&gt;
&lt;br /&gt;
对于任何具有相同节点数的图来说，点中心性的最大差异是:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ x = frac { sum _ { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i)}{ max sum _ { i = 1 ^ { n } c _ x (p _ *)-c _ x (p _ i)} . &amp;lt;/math &amp;gt;&lt;br /&gt;
&lt;br /&gt;
== Dissimilarity based centrality measures ==&lt;br /&gt;
==基于相异性的中心性度量==&lt;br /&gt;
&lt;br /&gt;
[[File:Srep17095-f1.jpg|thumbnail|In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.]]&lt;br /&gt;
&lt;br /&gt;
In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.&lt;br /&gt;
&lt;br /&gt;
在图示的网络中，绿色节点和红色节点最不相似，因为它们之间不共享相邻节点。因此，绿色的节点比灰色的节点对中心性的贡献更大，因为红色的节点只能通过绿色访问蓝色的节点，而灰色的节点对于红色的节点是多余的，因为它可以直接访问每个灰色的节点，而不需要任何中介。&lt;br /&gt;
&lt;br /&gt;
In order to obtain better results in the ranking of the nodes of a given network,  in &amp;lt;ref&amp;gt;{{Cite journal|title = Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|journal = Scientific Reports|date = 2015-11-25|pmc = 4658528|pmid = 26603652|volume = 5|doi = 10.1038/srep17095|first = A. J.|last = Alvarez-Socorro|first2 = G. C.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz|pages=17095|bibcode = 2015NatSR...517095A}}&amp;lt;/ref&amp;gt; are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with [[eigenvector centrality]], calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
&lt;br /&gt;
In order to obtain better results in the ranking of the nodes of a given network,  in  are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with eigenvector centrality, calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
&lt;br /&gt;
为了在给定网络节点的排序中获得更好的结果，在复杂网络中使用了相异性度量(特定于分类和数据挖掘理论)来丰富中心性度量。特征向量中心性通过求解特征值问题来计算每个节点的中心性&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
数学，数学&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary [[Matrix similarity|dissimilarity]] matrix, defined through a dissimilitary measure, e.g., [[Jaccard index|Jaccard]] dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary dissimilarity matrix, defined through a dissimilitary measure, e.g., Jaccard dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
这里 &amp;lt; math &amp;gt; w { ij } = a { ij } d { ij } &amp;lt;/math &amp;gt; (coordinate-to-coordinate product)和 &amp;lt; math &amp;gt; d { ij } &amp;lt;/math &amp;gt; 是一个任意的不相似矩阵，通过一个双重军事度量来定义，例如，Jaccard 由&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1-dfrac { | v ^ { + }(i) cap v ^ { + }(j) | }{ | v ^ { + }(i) cup v ^ { + }(j) | } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
&lt;br /&gt;
Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
&lt;br /&gt;
这种度量允许我们量化每个节点对给定节点中心性的拓扑贡献(这就是为什么我们称之为贡献中心性) ，对那些相异性较大的节点有更多的权重/相关性，因为这些节点允许给定的节点访问那些它们自己不能直接访问的节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the [[Perron–Frobenius theorem]] to ensure that the above problem has a unique solution for ''λ'' = ''λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt;'' with '''c''' non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
&lt;br /&gt;
Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the Perron–Frobenius theorem to ensure that the above problem has a unique solution for λ = λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt; with c non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
&lt;br /&gt;
值得注意的是，&amp;lt; math &amp;gt; w &amp;lt;/math &amp;gt; 是非负的，因为 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; d &amp;lt;/math &amp;gt; 都是非负矩阵，所以我们可以使用 Perron 弗罗贝尼乌斯定理来确保上述问题对于 c 非负的 = &amp;lt; sub &amp;gt; max &amp;lt;/sub &amp;gt; 有唯一的解，这样我们就可以推断出网络中每个节点的中心性。因此，i-th 节点的中心性为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1{ n } sum { j = 1} ^ { n } w { ij } c { j } ，，，，，j = 1，cdots，n &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in &amp;lt;ref&amp;gt;{{Cite web|url = http://www.nature.com/article-assets/npg/srep/2015/151125/srep17095/extref/srep17095-s1.pdf|title = Supplementary Information for Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|date = |website = |publisher = Nature Publishing Group|last = Alvarez-Socorro|first = A.J.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz}}&amp;lt;/ref&amp;gt; obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in  obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是网络中的节点数。几个不同的措施和网络进行了测试，以获得在研究案例的改善的结果。&lt;br /&gt;
&lt;br /&gt;
==Extensions==&lt;br /&gt;
==扩展==&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality&amp;lt;ref&amp;gt;{{cite journal | last1 = Braha | first1 = D. | last2 = Bar-Yam | first2 = Y. | year = 2006 | title = From Centrality to Temporary Fame: Dynamic Centrality in Complex Networks | url = | journal = Complexity | volume = 12 | issue = 2| pages = 59–63 | doi=10.1002/cplx.20156| arxiv = physics/0611295 | bibcode = 2006Cmplx..12b..59B }}&amp;lt;/ref&amp;gt; in the context of time-dependent and temporal networks.&amp;lt;ref&amp;gt;{{cite journal | last1 = Hill | first1 = S.A. | last2 = Braha | first2 = D. | year = 2010 | title = Dynamic Model of Time-Dependent Complex Networks | url = | journal = Physical Review E | volume = 82 | issue = 4| page = 046105 | doi=10.1103/physreve.82.046105| pmid = 21230343 | arxiv = 0901.4407 | bibcode = 2010PhRvE..82d6105H }}&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Gross, T. and Sayama, H. (Eds.). 2009. ''Adaptive Networks: Theory, Models and Applications.'' Springer.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Holme, P. and Saramäki, J. 2013. ''Temporal Networks.'' Springer.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality in the context of time-dependent and temporal networks.&lt;br /&gt;
&lt;br /&gt;
经验和理论研究已经将静态网络中的中心性概念扩展到时间依赖网络和时间网络中的动态中心性。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&amp;lt;ref&amp;gt;{{cite journal | last1 = Opsahl | first1 = Tore | last2 = Agneessens | first2 = Filip | last3 = Skvoretz | first3 = John | title = Node centrality in weighted networks: Generalizing degree and shortest paths | doi = 10.1016/j.socnet.2010.03.006 | year = 2010 | pages = 245–251 | volume = 32 | journal = Social Networks | url = http://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | issue = 3 | access-date = 2010-04-23 | archive-url = https://web.archive.org/web/20180226080331/https://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | archive-date = 2018-02-26 | url-status = dead }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&lt;br /&gt;
&lt;br /&gt;
对加权网络的推广，见 Opsahl 等人。(2010).&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, '''group betweenness''' centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&amp;lt;ref name=&amp;quot;group1&amp;quot;&amp;gt;Everett, M. G. and Borgatti, S. P. (2005). Extending centrality. In P. J. Carrington, J. Scott and S. Wasserman (Eds.), ''Models and methods in social network analysis'' (pp. 57–76). New York: Cambridge University Press.&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;group2&amp;quot;&amp;gt;Puzis, R., Yagil, D., Elovici, Y., Braha, D. (2009).[http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf Collaborative attack on Internet users’ anonymity] {{Webarchive|url=https://web.archive.org/web/20131207133417/http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf |date=2013-12-07 }}, ''Internet Research'' '''19'''(1)&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, group betweenness centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&lt;br /&gt;
&lt;br /&gt;
中心性的概念也扩展到了群体层次。例如，组间的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''显示了连接穿过组的成对非组成员的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Geodesics &amp;lt;/font&amp;gt;'''的比例。&lt;br /&gt;
&lt;br /&gt;
==See also==&lt;br /&gt;
==又及==&lt;br /&gt;
* [[Alpha centrality]]&lt;br /&gt;
&lt;br /&gt;
* [[Core–periphery structure]]&lt;br /&gt;
&lt;br /&gt;
* [[Distance (graph theory)|Distance in graphs]]&lt;br /&gt;
&lt;br /&gt;
*阿尔法中心性&lt;br /&gt;
&lt;br /&gt;
*核心—外围结构&lt;br /&gt;
&lt;br /&gt;
*距离（图理论）图中的距离&lt;br /&gt;
&lt;br /&gt;
==Notes and references==&lt;br /&gt;
&lt;br /&gt;
{{Reflist}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Further reading==&lt;br /&gt;
拓展阅读&lt;br /&gt;
* Koschützki, D.; Lehmann, K. A.; Peeters, L.; Richter, S.; Tenfelde-Podehl, D. and Zlotowski, O. (2005) Centrality Indices. In Brandes, U. and Erlebach, T. (Eds.)  ''Network Analysis: Methodological Foundations'', pp.&amp;amp;nbsp;16–61, LNCS 3418, Springer-Verlag.&lt;br /&gt;
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[[Category:Graph theory]]&lt;br /&gt;
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Category:Graph theory&lt;br /&gt;
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分类: 图论&lt;br /&gt;
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[[Category:Graph algorithms]]&lt;br /&gt;
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Category:Graph algorithms&lt;br /&gt;
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分类: 图形算法&lt;br /&gt;
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[[Category:Algebraic graph theory]]&lt;br /&gt;
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Category:Algebraic graph theory&lt;br /&gt;
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分类: 代数图论&lt;br /&gt;
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[[Category:Networks]]&lt;br /&gt;
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Category:Networks&lt;br /&gt;
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分类: 网络&lt;br /&gt;
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[[Category:Network analysis]]&lt;br /&gt;
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Category:Network analysis&lt;br /&gt;
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分类: 网络分析&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Centrality]]. Its edit history can be viewed at [[网络中心性/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
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		<title>网络中心性</title>
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		<updated>2020-12-10T06:46:22Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：&lt;/p&gt;
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&lt;div&gt;此词条暂由水流心不竞初译，未经审校，带来阅读不便，请见谅。&lt;br /&gt;
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{{for|the statistical concept|Central tendency}}&lt;br /&gt;
{{Network Science}}&lt;br /&gt;
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In [[graph theory]] and [[network theory|network analysis]], indicators of '''centrality''' identify the most important [[vertex (graph theory)|vertices]] within a graph. Applications include identifying the most influential person(s) in a [[social network]], key infrastructure nodes in the [[Internet]] or [[urban network]]s, and [[super-spreader]]s of disease. Centrality concepts were first developed in [[social network analysis]], and many of the terms used to measure centrality reflect their [[sociology|sociological]] origin.&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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In graph theory and network analysis, indicators of centrality identify the most important vertices within a graph. Applications include identifying the most influential person(s) in a social network, key infrastructure nodes in the Internet or urban networks, and super-spreaders of disease. Centrality concepts were first developed in , and many of the terms used to measure centrality reflect their sociological origin.&lt;br /&gt;
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They should not be confused with [[node influence metric]]s, which seek to quantify the influence of every node in the network.&lt;br /&gt;
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They should not be confused with node influence metrics, which seek to quantify the influence of every node in the network.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;图论 graph theory &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络分析 network analysis &amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性 centrality &amp;lt;/font&amp;gt;'''指标用于识别图中最重要的顶点。其应用包括在社会网络中识别出最有影响力的个人，在因特网或城市网络中识别出最为关键的基础设施节点，以及识别疾病的超级传播者。中心性的概念最初由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;社会网络分析 social network analysis&amp;lt;/font&amp;gt;'''所发展，因此许多用于衡量中心性的术语都反映出了它们的社会学出身。&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;中心性不应与节点影响度相混淆，后者意在量化网络中每个节点的影响。&lt;br /&gt;
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==中心性指数的定义与特性Definition and characterization of centrality indices==&lt;br /&gt;
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Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性指数 centrality indices&amp;lt;/font&amp;gt;'''旨在探寻如何描绘重要节点这一问题。这一问题的答案通常实值函数的形式给出，可根据函数值将图中各节点进行排序，进而确定最为重要的节点。&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
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The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
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“重要性”的含义十分广泛，因此导致了许多不同的中心性定义方式。通常可以使用二分法将这些方式予以分类。&lt;br /&gt;
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&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important.&amp;lt;ref name=Borgatti2005/&amp;gt; &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt; Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important. Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&lt;br /&gt;
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“重要性”可以被设想为与网络中的某种流动或传输有关。这使得我们可以根据重要流动或传输的类型，对中心性予以分类。这些方法将中心性划分于完全不同的类别中，也就是说适用于一种类别中的中心性往往无法适用于其他类别。&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt; Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one ([[Centrality#Degree centrality|degree centrality]]) to infinite walks ([[Centrality#Eigenvector centrality|eigenvalue centrality]]).&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=&amp;quot;Benzi2013&amp;quot;&amp;gt;{{cite journal | last1=Benzi | first1=Michele | last2=Klymko| first2=Christine | year=2013 |title= A matrix analysis of different centrality measures |arxiv=1312.6722 | doi=10.1137/130950550 | volume=36 | issue=2 | journal=SIAM Journal on Matrix Analysis and Applications | pages=686–706}}&amp;lt;/ref&amp;gt; The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one (degree centrality) to infinite walks (eigenvalue centrality). The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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当中心性按照它们对'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 内聚性Cohesiveness&amp;lt;/font&amp;gt;'''的趋近程度来分类时，很明显，大多数中心性都集中在一个类别中。从一个给定顶点开始对步数计数，不同之处只在于行走的定义和计数方式。对该组描述的约束限制，从位置中心（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心度Degree centrality&amp;lt;/font&amp;gt;'''）到单元域（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征中心度Eigenvalue centrality&amp;lt;/font&amp;gt;'''），观察到许多中心性都有这种相似关系，这也许可以解释这些指数之间的高阶相关性。&lt;br /&gt;
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===Characterization by network flows==&lt;br /&gt;
==网络流特征==&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at once.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at oe.&lt;br /&gt;
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一个网络可以被看成是对某种物体流动的路径描述。使基于流的类型和由中心性编码的路径类型（同时）得到表征。一个流可以基于传输，每个不可分割的项目从一个节点到另一个节点，就像一个包裹从配送站送到客户的房子。第二种情况是串行复制，在这种情况下，一个项从源节点被复制到达目标节点。例如通过流言传播信息，以私有方式传播信息，并在流程结束时通知源节点和目标节点。最后一种情况是并行复制，即同时将项目复制到多个链接，就像无线电广播一次性向多个听众提供相同的信息。&lt;br /&gt;
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Likewise, the type of path can be constrained to [[Distance (graph theory)|geodesics]] (shortest paths), [[Glossary of graph theory terms#path|paths]]  (no vertex is visited more than once), [[Glossary of graph theory terms#trail|trails]] (vertices can be visited multiple times, no edge is traversed more than once), or [[Glossary of graph theory terms#walk|walks]] (vertices and edges can be visited/traversed multiple times).&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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Likewise, the type of path can be constrained to geodesics (shortest paths), paths  (no vertex is visited more than once), trails (vertices can be visited multiple times, no edge is traversed more than once), or walks (vertices and edges can be visited/traversed multiple times).&lt;br /&gt;
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同样，路径类型可以被限定为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Distance &amp;lt;/font&amp;gt;'''(最短路径)、路径(对顶点的访问不超过一次)、小径(可以访问多次顶点，没有边被访问超过一次)或者步子(可以访问/遍历多次顶点和边)。&lt;br /&gt;
===Characterization by walk structure===&lt;br /&gt;
==行走结构特征==&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either ''radial'' or ''medial.'' Radial centralities count walks which start/end from the given vertex. The [[Centrality#Degree centrality|degree]] and [[Centrality#Eigenvector centrality|eigenvalue]] centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's [[Centrality#Betweenness centrality|betweenness]] centrality, the number of shortest paths which pass through the given vertex.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either radial or medial. Radial centralities count walks which start/end from the given vertex. The degree and eigenvalue centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's betweenness centrality, the number of shortest paths which pass through the given vertex.&lt;br /&gt;
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可以从中心性的构造方式推导出另一种分类方法。这又分成了两个类。中心点可以是放射状的，也可以是内侧的。从给定顶点开始/结束的径向中心点数。度和特征值中心是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 径向中心Radial centralities&amp;lt;/font&amp;gt;'''的例子，计算长度为一或无穷大的行走的个数。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中间中心性Medial centralities&amp;lt;/font&amp;gt;'''计算通过给定顶点的步数。典型的例子是 弗里曼的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality,&amp;lt;/font&amp;gt;'''，即穿过给定顶点的最短路径的数量。&lt;br /&gt;
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Likewise, the counting can capture either the ''volume'' or the ''length'' of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's [[Centrality#Closeness centrality|closeness]] centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example.&amp;lt;ref name=Borgatti2006/&amp;gt; Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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Likewise, the counting can capture either the volume or the length of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's closeness centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example. Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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同样地，计数可以抓住行走的体积或长度。体积是给定类型的行走的总数。上一段的三个例子就属于这一类。长度则给出从给定顶点到图中其余顶点的距离。弗里曼 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，即从一个给定顶点到所有其他顶点的测地距离，是最著名的例子。请注意，这种分类独立于步行计数的类型(即：步行，小道，路径，测地线)。&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&lt;br /&gt;
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博尔加蒂和埃弗雷特提出，这种类型学为如何最好地比较中心性度量提出了建议。在这个22分类中，放在同一盒子中的中心点足够相似，可以做出合理的选择; 人们可以合理地比较哪个对于给定的应用更好。然而，不同盒子中的度量方法是截然不同的。只有在预先确定哪个类别更适用的情况下，对相对适应性的评估才会发生，这使得比较变得毫无意义。&lt;br /&gt;
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===Radial-volume centralities exist on a spectrum===&lt;br /&gt;
==光谱上存在的径向体积中心==&lt;br /&gt;
The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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步行结构的特征表明，几乎所有广泛使用的中心性都是径向体积的衡量。这得出结论顶点的中心性是与之相关联的顶点中心性的函数。中心性根据如何定义关联而不同。&lt;br /&gt;
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Bonacich showed that if association is defined in terms of [[Glossary of graph theory terms#walk|walks]], then a family of centralities can be defined based on the length of walk considered.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;/&amp;gt; [[Centrality#Degree centrality|Degree centrality]] counts walks of length one, while [[Centrality#Eigenvector centrality|eigenvalue centrality]] counts walks of length infinity. Alternative definitions of association are also reasonable. [[Alpha centrality]] allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich showed that if association is defined in terms of walks, then a family of centralities can be defined based on the length of walk considered. Degree centrality counts walks of length one, while eigenvalue centrality counts walks of length infinity. Alternative definitions of association are also reasonable. Alpha centrality allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich 指出，如果联想是根据行走来定义的，那么可以根据考虑的行走长度来定义一个中心性家族。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''计算长度为1的行走，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征值中心性Eigenvalue centrality  &amp;lt;/font&amp;gt;'''计算长度为无穷大的行走。关联的其他定义也是合理的。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 阿尔法中心性Alpha centrality&amp;lt;/font&amp;gt;'''允许顶点有一个外部影响源。埃斯特拉达的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图中心性Subgraph centrality &amp;lt;/font&amp;gt;'''提出只计算封闭路径(三角形、正方形等)。).&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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这些测量方法的核心是这种现象：图中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵&amp;lt;/font&amp;gt;'''的幂给出了由该幂给出的散步长度的数目。同样，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 矩阵指数Matrix exponential&amp;lt;/font&amp;gt;'''也与给定长度的行走次数密切相关。邻接矩阵的初始转换允许对步行计数的类型进行不同的定义。无论采用哪种方法，顶点的中心性都可以表示为无穷和&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum _ { k = 0} ^ infty a _ { r } ^ { k } beta ^ k &amp;lt;/math &amp;gt; &lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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矩阵能量或者&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum { k = 0} ^ infty frac {(a _ r beta) ^ k }{ k！{/math &amp;gt; &lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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对于矩阵指数函数，其中&lt;br /&gt;
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* &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; is walk length,&lt;br /&gt;
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* &amp;lt;math&amp;gt;A_R&amp;lt;/math&amp;gt; is the transformed adjacency matrix, and&lt;br /&gt;
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* &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; is a discount parameter which ensures convergence of the sum.&lt;br /&gt;
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K为步长，A_R是邻接矩阵的转秩，贝达是保证收敛的折扣参数。&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. [[Alpha centrality]] replaces the adjacency matrix with its [[resolvent formalism|resolvent]]. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to [[Centrality#Degree centrality|degree centrality]]. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to [[Centrality#Eigenvector centrality|eigenvalue centrality]].&amp;lt;ref name=Benzi2013/&amp;gt;&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. Alpha centrality replaces the adjacency matrix with its resolvent. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to degree centrality. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to eigenvalue centrality.&lt;br /&gt;
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博纳奇的一系列措施并没有改变邻接矩阵。阿尔法集中性用它的解决方案替代了邻接矩阵。子图集中性用它的踪迹取代了邻接矩阵。一个令人吃惊的结论是，不管邻接矩阵最初的转变是什么，所有这些方法都有共同的限制行为。随着贝塔系数趋近于零，指数收敛到度中心性。随着贝塔系数接近其最大值，指数收敛到特征值的中心性。&lt;br /&gt;
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===Game-theoretic centrality===&lt;br /&gt;
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=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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上述大多数标准措施的共同特点是，它们通过只关注一个节点本身所扮演的角色来评估确定节点的重要性。然而, 在许多应用中，这种方法是不充分的，因为可能会发生协同作用&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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如果将节点的功能分组考虑。&lt;br /&gt;
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[[File:Game-theoretic centrality.png|Example of game-theoretic centrality]]&lt;br /&gt;
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Example of game-theoretic centrality&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''的例子&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in &amp;lt;ref&amp;gt;Michalak, Aadithya, Szczepański, Ravindran, &amp;amp; Jennings {{ArXiv|1402.0567}}&amp;lt;/ref&amp;gt; uses the [[Shapley value]]. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in  uses the Shapley value. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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例如，考虑阻止流行病的问题。看看上面的网络图像，我们应该给哪些节点接种疫苗？基于前面描述的措施，我们希望识别在疾病传播中最重要的节点。仅仅基于中心的方法，即关注节点的个别特性，可能不是一个好主意。红色方块中的节点，单独不能阻止疾病的传播，但把它们作为一个群体来考虑，我们清楚地看到，如果疾病在节点 &amp;lt; math &amp;gt; v _ 1 &amp;lt;/math &amp;gt; 、 &amp;lt; math &amp;gt; v _ 4 &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; v _ 5 &amp;lt;/math &amp;gt; 中开始，它们就能阻止疾病的传播。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''试图利用博弈论中的工具来研究所描述的问题和机会。本文提出的方法使用了 Shapley 值。由于 Shapley 值计算的时间复杂性，这一领域的大部分工作都集中在实现新的算法和方法，这些算法和方法依赖于网络的特殊拓扑结构或问题的特殊性质。这种方法可以将时间复杂度从指数级降低到多项式级。&lt;br /&gt;
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Similarly, the solution concept [[authority distribution]] (&amp;lt;ref&amp;gt;{{cite journal |last=Hu |first=Xingwei |first2=Lloyd |last2=Shapley |title=On Authority Distributions in Organizations |journal=Games and Economic Behavior |volume=45 |pages=132–170 |year=2003 | doi = 10.1016/s0899-8256(03)00130-1 }}&amp;lt;/ref&amp;gt;) applies the [[Shapley-Shubik power index]], rather than the [[Shapley value]], to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020)&amp;lt;ref&amp;gt;{{cite journal|last=Hu|first=Xingwei|year=2020|volume=7|title=Sorting big data by revealed preference with application to college ranking |journal=Journal of Big Data|doi=10.1186/s40537-020-00300-1|doi-access=free}}&amp;lt;/ref&amp;gt;, such as ranking U.S. colleges.&lt;br /&gt;
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Similarly, the solution concept authority distribution () applies the Shapley-Shubik power index, rather than the Shapley value, to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020), such as ranking U.S. colleges.&lt;br /&gt;
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同样，'''&amp;lt;font color=&amp;quot;#CD32CD&amp;quot;&amp;gt; 加权分布概念的解()The solution concept authority distribution () &amp;lt;/font&amp;gt;'''采用 Shapley-Shubik 幂指数，而不是 Shapley 值来衡量双方之间的直接影响。这种分布确实是一种产生'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征向量中心性Engenvector centrality&amp;lt;/font&amp;gt;'''的类型。它用于对 Hu (2020)中的大数据对象进行排序，比如美国大学排名。&lt;br /&gt;
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== Important limitations ==&lt;br /&gt;
==重要限制==&lt;br /&gt;
Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the [[Krackhardt kite graph]], for which three different notions of centrality give three different choices of the most central vertex.&amp;lt;ref&amp;gt;{{cite journal|title=Assessing the Political Landscape: Structure, Cognition, and Power in Organizations|first=David|last=Krackhardt|authorlink=David Krackhardt|journal=Administrative Science Quarterly|volume=35|issue=2|date=June 1990|pages=342–369|doi=10.2307/2393394|jstor=2393394}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the Krackhardt kite graph, for which three different notions of centrality give three different choices of the most central vertex.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中心性Centrality&amp;lt;/font&amp;gt;'''指标有两个重要的局限性，一个显而易见，另一个则不易察觉。显而易见的局限性是，对于一个应用最优的中心性对于另一个应用常常是次优的。事实上，如果不是这样，我们就不需要这么多不同的中心性。克拉克哈特风筝图为这一现象提供了一个例证，对于这个图，三个不同的中心性概念给出了三个最中心顶点的不同选择。&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices.&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=Borgatti2005/&amp;gt; This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  [[node influence metric]]s to address this problem.&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices. This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  node influence metrics to address this problem.&lt;br /&gt;
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更不易察觉的限制是通常会错误地认为顶点中心性表示顶点的相对重要性。中心性指数被明确地设计来产生一个指出最重要顶点的排名。在刚才提到的限制下，他们做得很好。它们通常不用来测量节点的影响力。最近，网络物理学家开始开发'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;节点影响度量Node influence metrics &amp;lt;/font&amp;gt;'''来解决这个问题。&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying [[Centrality#Freeman centralization|Freeman centralization]] to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt; This approach, however, is seldom seen in practice.{{citation needed|reason=I've come across quite some theoretical studies that indicate otherwise. My suggestion is to remove this sentence, if reasonable citation is not provided.|date=September 2015}}&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying Freeman centralization to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores. This approach, however, is seldom seen in practice.&lt;br /&gt;
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错误有两方面。首先，一个排名只根据顶点的重要性排序，它并不对节点重要性的不同水平进行量化区分。这可以通过将 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;'''应用到中心性度量来缓解，这种度量可以根据节点的不同中心性得分来判断节点的重要性。此外， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;''使人们能够通过比较几个网络的最高中心性得分来比较它们。然而，这种方法在实践中很少见到。&lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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其次，用以(正确地)识别给定网络/应用中最重要顶点的特征并不一定可推广到其余顶点。&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot; /&amp;gt;&amp;lt;ref name=&amp;quot;daSilva2012&amp;quot;&amp;gt;{{cite journal | last1=da Silva|first1=Renato |last2=Viana|first2=Matheus|last3=da F. Costa |first3=Luciano| title=Predicting epidemic outbreak from individual features of the spreaders| journal=J. Stat. Mech.: Theory Exp. | year=2012|volume=2012|pages=P07005|number=7 | doi=10.1088/1742-5468/2012/07/p07005|arxiv=1202.0024|bibcode=2012JSMTE..07..005A}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Bauer2012&amp;quot;&amp;gt;{{cite journal | last1=Bauer|first1=Frank | last2=Lizier|first2=Joseph|title=Identifying influential spreaders and efficiently estimating infection numbers in epidemic models: A walk counting approach| journal=Europhys Lett | year=2012| volume=99| pages=68007|number=6 | doi=10.1209/0295-5075/99/68007|arxiv=1203.0502|bibcode=2012EL.....9968007B}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Sikic2013&amp;quot;&amp;gt;{{ cite journal| last1= Sikic| first1=Mile|last2=Lancic|first2=Alen|last3=Antulov-Fantulin|first3=Nino|last4=Stefanic|first4=Hrvoje| title = Epidemic centrality -- is there an underestimated epidemic impact of network peripheral nodes? |journal = The European Physical Journal B |volume=86 |number=10 |pages=1–13 |year=2013 | doi=10.1140/epjb/e2013-31025-5|arxiv=1110.2558 | bibcode=2013EPJB...86..440S}}&amp;lt;/ref&amp;gt; This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&amp;lt;ref name=&amp;quot;Ghoshal2011&amp;quot;&amp;gt;{{cite journal | last1=Ghoshal | first1= G. | last2= Barabsi |first2= A L | title = Ranking stability and super-stable nodes in complex networks. | journal = Nat Commun | volume =2 | page = 394| year= 2011 | doi=10.1038/ncomms1396 | pmid= 21772265 | bibcode=2011NatCo...2..394G | doi-access= free }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless. This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&lt;br /&gt;
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对于大多数其他网络节点，排名可能是没有意义的。这就解释了为什么，例如，只有谷歌图片搜索的前几个结果以合理的顺序出现。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页排名Pagerank&amp;lt;/font&amp;gt;'''是一个非常不稳定的度量，显示了在跳转参数小的调整之后频繁的秩逆转。&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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虽然中心性指数未能推广到网络的其他部分，乍看起来似乎是违反直觉的，但它直接遵循上述定义。&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot;&amp;gt;{{cite journal |last1= Lawyer |first1= Glenn |year= 2015 |title= Understanding the spreading power of all nodes in a network: a continuous-time perspective |journal=Sci Rep |volume=5|pages=8665|doi=10.1038/srep08665 |pmid=25727453 |pmc=4345333|arxiv=1405.6707|bibcode=2015NatSR...5E8665L}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&lt;br /&gt;
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复杂网络具有异构的拓扑结构。由于最佳度量取决于最重要顶点的网络结构，对于这些顶点最优的度量对于网络的其余部分是次优的。&lt;br /&gt;
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==Degree centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Degree (graph theory)}} &lt;br /&gt;
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&lt;br /&gt;
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[[File:6 centrality measures.png|thumb|right|300px|Examples of A) [[Betweenness centrality]], B) [[Closeness centrality]], C) [[Eigenvector centrality]], D) [[Degree centrality]], E) [[Centrality#Harmonic centrality|Harmonic centrality]] and F) [[Katz centrality]] of the same graph.]]&lt;br /&gt;
&lt;br /&gt;
Examples of A) [[Betweenness centrality, B) Closeness centrality, C) Eigenvector centrality, D) Degree centrality, E) Harmonic centrality and F) Katz centrality of the same graph.]]&lt;br /&gt;
&lt;br /&gt;
实例 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; a)[中介中心性A) [[Betweenness centrality,b)紧密中心性，B) Closeness centrality, c)特征向量中心性，C) Eigenvector centrality, d)度中心性，D) Degree centrality, e)调和中心性，E) Harmonic centrality andf) 卡兹Katz 中心性]F) Katz centrality .]]&amp;lt;/font&amp;gt;'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Historically first and conceptually simplest is '''degree centrality''', which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely [[indegree]] and [[outdegree]]. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
&lt;br /&gt;
Historically first and conceptually simplest is degree centrality, which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely indegree and outdegree. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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历史上最简单的概念是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''，它定义为一个节点上发生的链接数量(即一个节点拥有的关系数量)。度可以根据节点捕获流经网络的任何东西(例如病毒或某些信息)的直接风险来解释。在有向网络的情况下(其中联系有方向) ，我们通常定义两个独立的度量，即 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度 Outdegree&amp;lt;/font&amp;gt;'''。因此，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度indegree&amp;lt;/font&amp;gt;'''是指向该节点的关系数，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度outdegree&amp;lt;/font&amp;gt;'''是指该节点指向其他节点的关系数。当关系与一些积极的方面如友谊或合作有关时， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''通常被解释为一种形式的受欢迎，而 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度Indegree&amp;lt;/font&amp;gt;'''则被解释为合群。&lt;br /&gt;
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The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
&lt;br /&gt;
The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
&lt;br /&gt;
对于给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边，度的中心性定义为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Calculating degree centrality for all the nodes in a graph takes [[big theta|&amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt;]] in a [[dense matrix|dense]] [[adjacency matrix]] representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a [[sparse matrix]] representation.&lt;br /&gt;
&lt;br /&gt;
Calculating degree centrality for all the nodes in a graph takes &amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt; in a dense adjacency matrix representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a sparse matrix representation.&lt;br /&gt;
&lt;br /&gt;
计算一个图中所有节点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''需要在图的稠密'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵Adjacency matrix &amp;lt;/font&amp;gt;'''表示中使用 Theta (v ^ 2) &amp;lt;/math &amp;gt; ，而在稀疏矩阵表示中使用 Theta (e) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of ''graph centralization''.&amp;lt;ref&amp;gt;Freeman, Linton C. &amp;quot;Centrality in social networks conceptual clarification.&amp;quot; Social networks 1.3 (1979): 215–239.&amp;lt;/ref&amp;gt; Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
&lt;br /&gt;
The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of graph centralization. Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
&lt;br /&gt;
节点级中心性的定义可以扩展到整个图，在这种情况下，我们指的是图的集中性。设 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 为 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''最高的节点。让 &amp;lt; math &amp;gt; x: = (y，z) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; | y | &amp;lt;/math &amp;gt; 节点连接图，最大化下列数量(&amp;lt; math &amp;gt; y * &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 中度最高的节点) :&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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:&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h = sum ^ { | y | }{ j = 1}[ c _ d (y *)-c _ d (y _ j)] &amp;lt;/math &amp;gt; &lt;br /&gt;
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Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
&lt;br /&gt;
Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
&lt;br /&gt;
相应地，图形 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''如下:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ h } &amp;lt;/math &amp;gt; &lt;br /&gt;
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The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a [[star graph]]), and in this case&lt;br /&gt;
&lt;br /&gt;
The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a star graph), and in this case&lt;br /&gt;
&lt;br /&gt;
当图形 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 包含一个所有其他节点都连接的中心节点(一个星形图)时，&amp;lt; math &amp;gt; h &amp;lt;/math &amp;gt; 的值最大化，在这种情况下&lt;br /&gt;
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:&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
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(n-1)-1) = n ^ 2-3n + 2&lt;br /&gt;
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So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
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So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
所以，对于任意的图 &amp;lt; math &amp;gt; g: = (v，e) ，&amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ | v | ^ 2-3 | v | + 2} &amp;lt;/math &amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Closeness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Closeness centrality}}In a [[Connected component (graph theory)|connected]] [[Graph (discrete mathematics)|graph]], the [[Normalization (statistics)|normalized]] '''closeness centrality''' (or '''closeness''') of a node is the average length of the [[Shortest path problem|shortest path]] between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
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In a connected graph, the normalized closeness centrality (or closeness) of a node is the average length of the shortest path between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
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在连通图中，节点的标准'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''(或贴近性)是节点与图中所有其他节点之间最短路径的平均长度。因此，一个节点越是中心，它就越接近所有其他节点。&lt;br /&gt;
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Closeness was defined by [[Alex Bavelas]] (1950) as the [[Multiplicative inverse|reciprocal]] of the '''farness''',&amp;lt;ref&amp;gt;Alex Bavelas. Communication patterns in task-oriented groups. ''J. Acoust. Soc. Am'', '''22'''(6):725–730, 1950.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;{{cite journal|year=1966|title=The centrality index of a graph|url=|journal=Psychometrika|volume=31|issue=4|pages=581–603|doi=10.1007/bf02289527|pmid=5232444|hdl=10338.dmlcz/101401|last1=Sabidussi|first1=G|hdl-access=free}}&amp;lt;/ref&amp;gt; that is:&lt;br /&gt;
&lt;br /&gt;
Closeness was defined by Alex Bavelas (1950) as the reciprocal of the farness, that is:&lt;br /&gt;
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亚历克斯 · 巴维拉斯(1950)将亲密度定义为相对于距离的倒数，即:&lt;br /&gt;
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&lt;br /&gt;
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: &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
C (x) = frac {1}{ sum _ y d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the [[Distance (graph theory)|distance]] between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the distance between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; d (y，x) &amp;lt;/math &amp;gt; 是顶点 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; 之间的距离。然而，当谈到'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''时，人们通常会提到它的标准化形式，一般是以前的公式乘以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; ，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。这种调整允许比较不同大小图形的节点。&lt;br /&gt;
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Taking distances ''from'' or ''to'' all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in [[directed graph]]s (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
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Taking distances from or to all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in directed graphs (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
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从所有其他节点或到所有其他节点的距离在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 无向图Undirected graphs&amp;lt;/font&amp;gt;'''中是不相关的，但是在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 有向图Directed graphs&amp;lt;/font&amp;gt;'''中可能产生完全不同的结果(例如:一个网站可以从传出链接获得高的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，而从传入链接获得低的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''）。&lt;br /&gt;
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===Harmonic centrality===&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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In a (not necessarily connected) graph, the '''harmonic centrality''' reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the harmonic centrality reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
在一个(不一定是连通的)图中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''反转了'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''定义中的和互反运算:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h (x) = sum { y neq x } frac {1}{ d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; 1/d (y，x) = 0 &amp;lt;/math &amp;gt; if there is no path from &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; to &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 。调和中心性可以通过除以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; 来标准化，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。&lt;br /&gt;
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Harmonic centrality was proposed by [[Massimo Marchiori|Marchiori]] and [[Vito Latora|Latora]] (2000)&amp;lt;ref name=&amp;quot;marchiorilatora2000&amp;quot;&amp;gt;{{citation| journal = Physica A: Statistical Mechanics and Its Applications  | last1 = Marchiori | first1 = Massimo | last2 = Latora | first2 = Vito | year = 2000 | volume = 285 | issue = 3–4 | pages = 539–546 | title = Harmony in the small-world | doi=10.1016/s0378-4371(00)00311-3| arxiv = cond-mat/0008357 | bibcode = 2000PhyA..285..539M }}&amp;lt;/ref&amp;gt; and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot;&amp;lt;ref&amp;gt;{{cite journal|first1=Anthony|last1=Dekker|title=Conceptual Distance in Social Network Analysis|journal=Journal of Social Structure|volume=6|issue=3|year=2005|url=http://www.cmu.edu/joss/content/articles/volume6/dekker/index.html}}&amp;lt;/ref&amp;gt; and by Rochat (2009).&amp;lt;ref&amp;gt;{{cite conference  | author = Yannick Rochat  | title = Closeness centrality extended to unconnected graphs: The harmonic centrality index | conference = Applications of Social Network Analysis, ASNA 2009 | url = http://infoscience.epfl.ch/record/200525/files/%5bEN%5dASNA09.pdf }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Harmonic centrality was proposed by Marchiori and Latora (2000) and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot; and by Rochat (2009).&lt;br /&gt;
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调和中心性是由 Marchiori 和 Latora (2000)提出的，然后是 Dekker (2005)独立提出的，使用的名称是“有价值的中心性” ，Rochat (2009)。&lt;br /&gt;
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==Betweenness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Betweenness centrality}}&lt;br /&gt;
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[[File:Graph betweenness.svg|240px|right|thumb|Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.]]&lt;br /&gt;
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Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.&lt;br /&gt;
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色调(从红色 = 0到蓝色 = max)表示节点之间的距离。&lt;br /&gt;
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'''Betweenness''' is a centrality measure of a [[vertex (graph theory)|vertex]] within a [[Graph (discrete mathematics)|graph]] (there is also [[edge (graph theory)|edge]] betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by [[Linton Freeman]]&amp;lt;ref name=&amp;quot;freeman1977&amp;quot;&amp;gt;{{cite journal |last1 = Freeman |first1 = Linton | year=1977| title = A set of measures of centrality based upon betweenness | journal = Sociometry| volume=40|issue = 1 | pages=35–41 | doi=10.2307/3033543|jstor = 3033543 }}&amp;lt;/ref&amp;gt; In his conception, vertices that have a high probability to occur on a randomly chosen [[shortest path problem|shortest path]] between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
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Betweenness is a centrality measure of a vertex within a graph (there is also edge betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by Linton Freeman In his conception, vertices that have a high probability to occur on a randomly chosen shortest path between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
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中介性是图中顶点的中心性度量(也有边中介性，这里没有讨论)。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''量化了一个节点沿着其他两个节点之间的最短路径充当桥梁的次数。在林顿 · 弗里曼的概念中，在两个随机选择的顶点之间随机选择的最短路径上出现概率高的顶点具有很高的中介性。&lt;br /&gt;
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The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
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The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
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在一个图 &amp;lt; math &amp;gt; g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的顶点之间的距离计算如下:&lt;br /&gt;
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# For each pair of vertices (''s'',''t''), compute the [[Shortest path problem|shortest paths]] between them.&lt;br /&gt;
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 For each pair of vertices (s,t), compute the shortest paths between them.&lt;br /&gt;
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对于每一对顶点(s，t) ，计算它们之间的最短路径。&lt;br /&gt;
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# For each pair of vertices (''s'',''t''), determine the fraction of shortest paths that pass through the vertex in question (here, vertex ''v'').&lt;br /&gt;
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 For each pair of vertices (s,t), determine the fraction of shortest paths that pass through the vertex in question (here, vertex v).&lt;br /&gt;
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对于每对顶点(s，t) ，确定通过该顶点(这里是顶点 v)的最短路径的分数。&lt;br /&gt;
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# Sum this fraction over all pairs of vertices (''s'',''t'').&lt;br /&gt;
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 Sum this fraction over all pairs of vertices (s,t).&lt;br /&gt;
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对所有顶点对(s，t)求这个分数的和。&lt;br /&gt;
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More compactly the betweenness can be represented as:&amp;lt;ref name=&amp;quot;brandes&amp;quot;&amp;gt;{{cite journal |last1 = Brandes |first1 = Ulrik | year=2001 |title = A faster algorithm for betweenness centrality  | journal = Journal of Mathematical Sociology| volume=25|issue = 2 | pages=163–177| url = http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.11.2024 | accessdate = October 11, 2011| format = PDF | doi=10.1080/0022250x.2001.9990249|citeseerx = 10.1.1.11.2024 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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More compactly the betweenness can be represented as:&lt;br /&gt;
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更确切地说，两者之间的关系可以表示为:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
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{ math &amp;gt; c _ b (v) = sum _ { s neq v neq t in v } frac { sigma _ st }(v)}{ sigma _ st } &amp;lt;/math &amp;gt; &lt;br /&gt;
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&lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including ''v'', which for [[Digraph (mathematics)|directed graphs]] is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected [[Star (graph theory)|star graph]], the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including v, which for directed graphs is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected star graph, the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; sigma { st } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { st }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径数。有向图是 &amp;lt; math &amp;gt; (n-1)(n-2) &amp;lt;/math &amp;gt; ，无向图是 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; 。例如，在一个无向星图中，中心顶点(包含在每个可能的最短路径中)的中介性为 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; (1，如果标准化) ，而叶子(包含在没有最短路径中)的中介性为0。&lt;br /&gt;
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From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires [[Big O notation|&amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt;]] time with the [[Floyd–Warshall algorithm]]. However, on sparse graphs, [[Johnson's algorithm]] may be more efficient, taking [[Big O notation|&amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt;]] time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm&amp;lt;ref name=brandes/&amp;gt; which takes [[Big O notation|&amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt;]] time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&amp;lt;ref name=&amp;quot;brandes&amp;quot; /&amp;gt;&lt;br /&gt;
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From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires &amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt; time with the Floyd–Warshall algorithm. However, on sparse graphs, Johnson's algorithm may be more efficient, taking &amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt; time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm which takes &amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt; time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&lt;br /&gt;
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从计算的角度来看，图中所有顶点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介和紧密中心性Betweenness and Closeness centralities&amp;lt;/font&amp;gt;'''都涉及到计算图中所有顶点对之间的最短路径，这就需要用 Floyd-Warshall 算法计算时间。然而，对于稀疏图，约翰逊算法的效率可能更高，采用 &amp;lt; math &amp;gt; o (v ^ 2 log v + v e) &amp;lt;/math &amp;gt; 时间。在不加权图的情况下，可以用 Brandes 的算法进行计算，该算法需要 &amp;lt; math &amp;gt; o (v e) &amp;lt;/math &amp;gt; 时间。一般情况下，这些算法假定图是无向的，并且连通图中允许有圈和多条边。当专门处理网络图时，图通常没有环或多条边来维持简单的关系(其中的边表示两个人或顶点之间的联系)。在这种情况下，使用 Brandes 的算法将最终的中心性分数除以2来计算每条被重复计算的最短路径。&lt;br /&gt;
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==Eigenvector centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Eigenvector centrality}}&lt;br /&gt;
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'''Eigenvector centrality''' (also called '''eigencentrality''') is a measure of the influence of a [[node (networking)|node]] in a [[network (mathematics)|network]]. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&amp;lt;ref&amp;gt;{{cite journal|title = The mathematics of networks|url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf|author = M. E. J. Newman|accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;/&amp;gt; [[Google]]'s [[PageRank]] and the [[Katz centrality]] are variants of the eigenvector centrality.&amp;lt;ref name=&amp;quot;ams&amp;quot;&amp;gt;{{Cite web | url=http://www.ams.org/samplings/feature-column/fcarc-pagerank | title=American Mathematical Society}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Eigenvector centrality (also called eigencentrality) is a measure of the influence of a node in a network. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''(也称为特征中心性)是衡量网络中节点影响的一个指标。它将相对得分分配给网络中的所有节点，这是基于这样一个概念: 与得分较高的节点相比，与得分较低的节点相同的连接对所涉及的节点的得分贡献更大。&lt;br /&gt;
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=== Using the adjacency matrix to find eigenvector centrality ==&lt;br /&gt;
==使用'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''发现'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the [[adjacency matrix]], i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
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For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the adjacency matrix, i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
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对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 让 &amp;lt; math &amp;gt; a = (a { v，t }) &amp;lt;/math &amp;gt; 成为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''，即。如果顶点 &amp;lt; math &amp;gt; &amp;gt; v &amp;lt;/math &amp;gt; 与 math &amp;gt; t &amp;lt;/math &amp;gt; 相连，而 &amp;lt; math &amp;gt; a { v，t } = 0 &amp;lt;/math &amp;gt; 否则。顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分可以定义为:&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
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在 m (v)} x _ t = frac {1}{ lambda } sum { t in g } a { v，t } x _ t &amp;lt;/math &amp;gt; &lt;br /&gt;
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where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the [[eigenvector]] equation&lt;br /&gt;
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where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the eigenvector equation&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; m (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 和 &amp;lt; math &amp;gt; &amp;gt; lambda &amp;lt;/math &amp;gt; 的邻居集合。通过一个小的重新排列，这可以被重写成向量符号，作为特征向量方程&lt;br /&gt;
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:&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
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[ math &amp;gt; mathbf { Ax } = { lambda } mathbf { x } &amp;lt;/math &amp;gt; &lt;br /&gt;
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In general, there will be many different [[eigenvalue]]s &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the [[Perron–Frobenius theorem]]. This greatest eigenvalue results in the desired centrality measure.&amp;lt;ref&amp;gt;{{cite journal  | author = M. E. J. Newman  | title = The mathematics of networks  | url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf  | accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt; The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices ''n''. [[Power iteration]] is one of many [[eigenvalue algorithm]]s that may be used to find this dominant eigenvector.&amp;lt;ref name=&amp;quot;ams&amp;quot; /&amp;gt; Furthermore, this can be generalized so that the entries in ''A'' can be real numbers representing connection strengths, as in a [[stochastic matrix]].&lt;br /&gt;
&lt;br /&gt;
In general, there will be many different eigenvalues &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the Perron–Frobenius theorem. This greatest eigenvalue results in the desired centrality measure. The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices n. Power iteration is one of many eigenvalue algorithms that may be used to find this dominant eigenvector. Furthermore, this can be generalized so that the entries in A can be real numbers representing connection strengths, as in a stochastic matrix.&lt;br /&gt;
&lt;br /&gt;
一般情况下，存在许多不同的特征值，对于这些特征值存在一个非零特征向量解。由于邻接矩阵中的条目是非负的，所以由 Perron-弗罗贝尼乌斯定理得出，它有一个实的和正的唯一最大特征值。由这个最大的特征值得出期望的中心性度量。相关特征向量的 &amp;lt; math &amp;gt; v ^ { th } &amp;lt;/math &amp;gt; 分量给出了网络中顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分。特征向量只定义了一个公共因子，所以只有顶点中心的比例是明确定义的。要定义一个绝对分数，必须对特征向量进行标准化，例如，使所有顶点的和为1或顶点的总数n。此外，这可以通用，使得 a 中的条目可以是表示连接强度的真实数字，就像'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 随机矩阵Stochastic matrix&amp;lt;/font&amp;gt;'''中一样。&lt;br /&gt;
&lt;br /&gt;
==Katz centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Katz centrality}}&lt;br /&gt;
&lt;br /&gt;
'''Katz centrality'''&amp;lt;ref&amp;gt;Katz, L. 1953. A New Status Index Derived from Sociometric Index. Psychometrika, 39–43.&amp;lt;/ref&amp;gt; is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
Katz centrality is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''是度中心性的推广。度中心性度量的是直接邻居的数量，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''度量的是通过一条路径可以连接的所有节点的数量，而远处节点的贡献会受到'''&amp;lt;font color=&amp;quot;#32CD32&amp;quot;&amp;gt; '削弱（惩罚？）Penalized&amp;lt;/font&amp;gt;''。在数学上，它被定义为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[数学][数学]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; (0,1) &amp;lt;/math &amp;gt; 中的衰减因子。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
&lt;br /&gt;
Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''可以看作是特征向量中心性的变体。Katz 中心性的另一种形式是&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
(x _ j + 1) &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
与特征向量中心性的表达式相比，&amp;lt; math &amp;gt; x _ j &amp;lt;/math &amp;gt; 被 &amp;lt; math &amp;gt; x _ j + 1所代替&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
It is shown that&amp;lt;ref&amp;gt;{{cite journal | last1 = Bonacich | first1 = P | year = 1991 | title = Simultaneous group and individual centralities | url = | journal = Social Networks | volume = 13 | issue = 2| pages = 155–168 | doi=10.1016/0378-8733(91)90018-o}}&amp;lt;/ref&amp;gt; the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
&lt;br /&gt;
It is shown that the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
&lt;br /&gt;
结果表明，主特征向量(与 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; ，邻接矩阵的最大特征值相关)是 Katz 中心性的极限，因为 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 接近 &amp;lt; math &amp;gt; tfrac {1}{ lambda } &amp;lt;/math &amp;gt; 。&lt;br /&gt;
&lt;br /&gt;
== PageRank centrality ==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页分布中心性PageRank&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
{{main|PageRank}}'''[[PageRank]]''' satisfies the following equation&lt;br /&gt;
&lt;br /&gt;
PageRank satisfies the following equation&lt;br /&gt;
&lt;br /&gt;
PageRank满足下面的等式&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1-alpha { n } ，&amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
其中&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[ math &amp;gt; l (j) = sum { i } a { ji } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&amp;lt;ref&amp;gt;[http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf How does Google rank webpages?] {{webarchive | url= https://web.archive.org/web/20120131083328/http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf |date=January 31, 2012 }} 20Q: About Networked Life&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&lt;br /&gt;
&lt;br /&gt;
是节点 &amp;lt; math &amp;gt; j &amp;lt;/math &amp;gt; (或有向图中出站链接的数量)的邻居数量。与特征向量中心性和 Katz 中心性相比，尺度因子 &amp;lt; math &amp;gt; l (j) &amp;lt;/math &amp;gt; 是一个主要的区别。PageRank 和特征向量中心性的另一个区别是 PageRank 向量是一个左手特征向量(注意因子 &amp;lt; math &amp;gt; a _ { ji } &amp;lt;/math &amp;gt; 具有相反的索引)。&lt;br /&gt;
&lt;br /&gt;
==Percolation centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&amp;lt;ref name=&amp;quot;piraveenan2013&amp;quot;&amp;gt;{{cite journal |last1 = Piraveenan |first1 = M. |last2 = Prokopenko |first2 = M.|last3 = Hossain|first3 = L. |year=2013| title = Percolation Centrality: Quantifying Graph-Theoretic Impact of Nodes during Percolation in Networks | journal = PLOS One | volume=8 | issue=1 | doi=10.1371/journal.pone.0053095 | pages=e53095 | pmid=23349699 | pmc=3551907| bibcode=2013PLoSO...853095P }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&lt;br /&gt;
&lt;br /&gt;
在复杂网络中，存在大量的中心性度量来确定单个节点的“重要性”。然而，这些度量单纯从拓扑学的角度来量化节点的重要性，节点的值并不以任何方式依赖于节点的状态。不管网络动态如何，它都保持不变。即使对于加权的两者之间的度量也是如此。然而，一个节点可能很好地位于'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''或其他中心性度量的中心位置，但可能不是位于有过滤的网络的上下文中的中心位置。在许多情况下，复杂网络中都会出现“传染”现象。例如，病毒或细菌感染可以通过人们的社交网络传播，也就是所谓的接触网络。还可以在更高的抽象层次上考虑疾病的传播问题，设想通过公路、铁路或空中连接起来的城镇或人口中心网络。计算机病毒可以通过计算机网络传播。关于商业活动和交易的谣言或新闻也可以通过人们的社交网络传播。在所有这些情况下，一种“传染病”在一个复杂网络的链接上传播，随着它的传播，无论是可恢复的还是不可恢复的，都会改变节点的“状态”。例如，在流行病学方案中，随着感染扩散，个人从”易感”状态转变为”受感染”状态。在上面的例子中，随着传染的扩散，每个节点可以采取的状态可以是二进制的(例如接收/没有接收到一条新闻)、离散的(易感/受感染/康复) ，甚至是连续的(例如一个城镇中受感染的人的比例) 。这些情景的共同特点是，传染的扩散导致网络中节点状态的改变。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''（PC)就是基于这个思想而提出的，它特别地衡量了节点在协助网络渗滤方面的重要性。这项措施是由 piraveanan 等人提出的。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
'''Percolation centrality''' is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
&lt;br /&gt;
Percolation centrality is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''定义为在给定时间内一个给定节点的过滤路径的比例。“渗滤路径”是一对节点之间的最短路径，其中源节点被渗滤(例如，被感染)。目标节点可以是过滤的或非过滤的，或处于部分过滤状态。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; PC ^ t (v) = frac {1}{ N-2} sum { s neq v neq r } frac { sigma { sr }(v)}{ sigma { sr }} frac { x ^ t }{ sum {[{ x ^ t } i }}}]}}-{ x ^ t }{ v } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; σ { sr } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; r &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { sr }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径的总数。在时间 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 时，节点的过滤状态用 &amp;lt; math &amp;gt; { x ^ t } _ i &amp;lt;/math &amp;gt; 表示，两个特殊情况是当 &amp;lt; math &amp;gt; { x ^ t } _ i = 0 &amp;lt;/math &amp;gt; 表示在时间上是非过滤状态，而当 &amp;lt; math &amp;gt; &amp;lt; x ^ t &amp;lt;/math &amp;gt; i = 1 &amp;lt;/math &amp;gt; 表示在时间上是完全过滤状态。两者之间的值表示部分过滤状态(例如，在一个城镇网络中，这是该城镇感染者的百分比)。&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in [[Big O notation|&amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt;]] time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is [[Big O notation|&amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;]].&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in &amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt; time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is &amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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渗流路径的权重取决于分配给源节点的渗流水平，前提是源节点的渗流水平越高，源节点的路径就越重要。因此，位于源自高渗滤节点的最短路径上的节点可能对渗滤更为重要。PC 的定义也可以扩展到包括目标节点的权重。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''计算运行在 &amp;lt; math &amp;gt; o (NM) &amp;lt;/math &amp;gt; 时间，采用了 Brandes 快速算法的有效实现，如果计算需要考虑目标节点的权重，最坏情况下时间为 &amp;lt; math &amp;gt; o (n ^ 3) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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==Cross-clique centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 交叉团中心性Cross-clique centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
'''Cross-clique centrality''' of a single node in a complex graph determines the connectivity of a node to different [[clique (graph theory)|clique]]s. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in &amp;lt;ref name=&amp;quot;xssworms&amp;quot;&amp;gt;{{cite journal |last1 = Faghani|first1 = Mohamamd Reza| year=2013| title = A Study of XSS Worm Propagation and Detection Mechanisms in Online Social Networks | journal = IEEE Transactions on Information Forensics and Security|volume = 8|issue = 11|pages = 1815–1826|doi = 10.1109/TIFS.2013.2280884}}&amp;lt;/ref&amp;gt; but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
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Cross-clique centrality of a single node in a complex graph determines the connectivity of a node to different cliques. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in  but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
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复杂图中单个节点的跨团中心性决定了一个节点与不同团的连通性。具有高度跨团连通性的节点有利于信息或疾病在图中的传播。团是一种'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图Subgraphs&amp;lt;/font&amp;gt;'''，团中的每个节点都与团中的其他节点相连。对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边的交叉团连通性，定义为 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; x (v) &amp;lt;/math &amp;gt; 其中 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 所属的顶点团数。这个测度应用日久，但是在1998年由 Everett 和 Borgatti 首次提出，他们称之为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 派系重叠中心性Clique-overlap centrality&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Freeman centralization==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心度Freeman centralization&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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The '''centralization''' of any network is a measure of how central its most central node is in relation to how central all the other nodes are.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;&amp;gt;{{citation | journal = Social Networks | last1 = Freeman | first1 = Linton C. | year = 1979 | volume = 1 | issue = 3 | pages = 215–239 | title = centrality in social networks: Conceptual clarification | url = http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | doi = 10.1016/0378-8733(78)90021-7 | citeseerx = 10.1.1.227.9549 | access-date = 2014-07-31 | archive-url = https://web.archive.org/web/20160222033108/http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | archive-date = 2016-02-22 | url-status = dead }}&amp;lt;/ref&amp;gt; Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
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The centralization of any network is a measure of how central its most central node is in relation to how central all the other nodes are. Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
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任何网络的集中度都是衡量其最核心的节点相对于其他所有节点的集聚程度的标准。集中度的度量方法是: (a)计算网络中最中心的节点与所有其他节点之间的中心性差异之和; (b)将这个数量除以理论上相同规模的任何网络中这种差异之和的最大值。因此，每个中心性度量都可以有自己的集中性度量。正式定义，如果 &amp;lt; math &amp;gt; c _ x (p _ i) &amp;lt;/math &amp;gt; 是点 &amp;lt; math &amp;gt; i &amp;lt;/math &amp;gt; 的中心性度量，如果 &amp;lt; math &amp;gt; c _ x (p _ *) &amp;lt;/math &amp;gt; 是网络中最大的中心性度量，如果:&lt;br /&gt;
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:&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; max sum { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i) &amp;lt;/math &amp;gt; &lt;br /&gt;
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is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;&lt;br /&gt;
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is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&lt;br /&gt;
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对于任何具有相同节点数的图来说，点中心性的最大差异是:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; c _ x = frac { sum _ { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i)}{ max sum _ { i = 1 ^ { n } c _ x (p _ *)-c _ x (p _ i)} . &amp;lt;/math &amp;gt;&lt;br /&gt;
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== Dissimilarity based centrality measures ==&lt;br /&gt;
==基于相异性的中心性度量==&lt;br /&gt;
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[[File:Srep17095-f1.jpg|thumbnail|In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.]]&lt;br /&gt;
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In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.&lt;br /&gt;
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在图示的网络中，绿色节点和红色节点最不相似，因为它们之间不共享相邻节点。因此，绿色的节点比灰色的节点对中心性的贡献更大，因为红色的节点只能通过绿色访问蓝色的节点，而灰色的节点对于红色的节点是多余的，因为它可以直接访问每个灰色的节点，而不需要任何中介。&lt;br /&gt;
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In order to obtain better results in the ranking of the nodes of a given network,  in &amp;lt;ref&amp;gt;{{Cite journal|title = Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|journal = Scientific Reports|date = 2015-11-25|pmc = 4658528|pmid = 26603652|volume = 5|doi = 10.1038/srep17095|first = A. J.|last = Alvarez-Socorro|first2 = G. C.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz|pages=17095|bibcode = 2015NatSR...517095A}}&amp;lt;/ref&amp;gt; are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with [[eigenvector centrality]], calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
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In order to obtain better results in the ranking of the nodes of a given network,  in  are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with eigenvector centrality, calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
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为了在给定网络节点的排序中获得更好的结果，在复杂网络中使用了相异性度量(特定于分类和数据挖掘理论)来丰富中心性度量。特征向量中心性通过求解特征值问题来计算每个节点的中心性&lt;br /&gt;
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:&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
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数学，数学&lt;br /&gt;
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where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary [[Matrix similarity|dissimilarity]] matrix, defined through a dissimilitary measure, e.g., [[Jaccard index|Jaccard]] dissimilarity given by&lt;br /&gt;
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where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary dissimilarity matrix, defined through a dissimilitary measure, e.g., Jaccard dissimilarity given by&lt;br /&gt;
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这里 &amp;lt; math &amp;gt; w { ij } = a { ij } d { ij } &amp;lt;/math &amp;gt; (coordinate-to-coordinate product)和 &amp;lt; math &amp;gt; d { ij } &amp;lt;/math &amp;gt; 是一个任意的不相似矩阵，通过一个双重军事度量来定义，例如，Jaccard 由&lt;br /&gt;
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:&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
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1-dfrac { | v ^ { + }(i) cap v ^ { + }(j) | }{ | v ^ { + }(i) cup v ^ { + }(j) | } &amp;lt;/math &amp;gt; &lt;br /&gt;
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Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
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Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
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这种度量允许我们量化每个节点对给定节点中心性的拓扑贡献(这就是为什么我们称之为贡献中心性) ，对那些相异性较大的节点有更多的权重/相关性，因为这些节点允许给定的节点访问那些它们自己不能直接访问的节点。&lt;br /&gt;
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Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the [[Perron–Frobenius theorem]] to ensure that the above problem has a unique solution for ''λ'' = ''λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt;'' with '''c''' non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
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Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the Perron–Frobenius theorem to ensure that the above problem has a unique solution for λ = λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt; with c non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
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值得注意的是，&amp;lt; math &amp;gt; w &amp;lt;/math &amp;gt; 是非负的，因为 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; d &amp;lt;/math &amp;gt; 都是非负矩阵，所以我们可以使用 Perron 弗罗贝尼乌斯定理来确保上述问题对于 c 非负的 = &amp;lt; sub &amp;gt; max &amp;lt;/sub &amp;gt; 有唯一的解，这样我们就可以推断出网络中每个节点的中心性。因此，i-th 节点的中心性为&lt;br /&gt;
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:&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
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1{ n } sum { j = 1} ^ { n } w { ij } c { j } ，，，，，j = 1，cdots，n &amp;lt;/math &amp;gt; &lt;br /&gt;
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where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in &amp;lt;ref&amp;gt;{{Cite web|url = http://www.nature.com/article-assets/npg/srep/2015/151125/srep17095/extref/srep17095-s1.pdf|title = Supplementary Information for Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|date = |website = |publisher = Nature Publishing Group|last = Alvarez-Socorro|first = A.J.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz}}&amp;lt;/ref&amp;gt; obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in  obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是网络中的节点数。几个不同的措施和网络进行了测试，以获得在研究案例的改善的结果。&lt;br /&gt;
&lt;br /&gt;
==Extensions==&lt;br /&gt;
==扩展==&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality&amp;lt;ref&amp;gt;{{cite journal | last1 = Braha | first1 = D. | last2 = Bar-Yam | first2 = Y. | year = 2006 | title = From Centrality to Temporary Fame: Dynamic Centrality in Complex Networks | url = | journal = Complexity | volume = 12 | issue = 2| pages = 59–63 | doi=10.1002/cplx.20156| arxiv = physics/0611295 | bibcode = 2006Cmplx..12b..59B }}&amp;lt;/ref&amp;gt; in the context of time-dependent and temporal networks.&amp;lt;ref&amp;gt;{{cite journal | last1 = Hill | first1 = S.A. | last2 = Braha | first2 = D. | year = 2010 | title = Dynamic Model of Time-Dependent Complex Networks | url = | journal = Physical Review E | volume = 82 | issue = 4| page = 046105 | doi=10.1103/physreve.82.046105| pmid = 21230343 | arxiv = 0901.4407 | bibcode = 2010PhRvE..82d6105H }}&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Gross, T. and Sayama, H. (Eds.). 2009. ''Adaptive Networks: Theory, Models and Applications.'' Springer.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Holme, P. and Saramäki, J. 2013. ''Temporal Networks.'' Springer.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality in the context of time-dependent and temporal networks.&lt;br /&gt;
&lt;br /&gt;
经验和理论研究已经将静态网络中的中心性概念扩展到时间依赖网络和时间网络中的动态中心性。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&amp;lt;ref&amp;gt;{{cite journal | last1 = Opsahl | first1 = Tore | last2 = Agneessens | first2 = Filip | last3 = Skvoretz | first3 = John | title = Node centrality in weighted networks: Generalizing degree and shortest paths | doi = 10.1016/j.socnet.2010.03.006 | year = 2010 | pages = 245–251 | volume = 32 | journal = Social Networks | url = http://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | issue = 3 | access-date = 2010-04-23 | archive-url = https://web.archive.org/web/20180226080331/https://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | archive-date = 2018-02-26 | url-status = dead }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&lt;br /&gt;
&lt;br /&gt;
对加权网络的推广，见 Opsahl 等人。(2010).&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, '''group betweenness''' centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&amp;lt;ref name=&amp;quot;group1&amp;quot;&amp;gt;Everett, M. G. and Borgatti, S. P. (2005). Extending centrality. In P. J. Carrington, J. Scott and S. Wasserman (Eds.), ''Models and methods in social network analysis'' (pp. 57–76). New York: Cambridge University Press.&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;group2&amp;quot;&amp;gt;Puzis, R., Yagil, D., Elovici, Y., Braha, D. (2009).[http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf Collaborative attack on Internet users’ anonymity] {{Webarchive|url=https://web.archive.org/web/20131207133417/http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf |date=2013-12-07 }}, ''Internet Research'' '''19'''(1)&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, group betweenness centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&lt;br /&gt;
&lt;br /&gt;
中心性的概念也扩展到了群体层次。例如，组间的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''显示了连接穿过组的成对非组成员的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Geodesics &amp;lt;/font&amp;gt;'''的比例。&lt;br /&gt;
&lt;br /&gt;
==See also==&lt;br /&gt;
==又及==&lt;br /&gt;
* [[Alpha centrality]]&lt;br /&gt;
&lt;br /&gt;
* [[Core–periphery structure]]&lt;br /&gt;
&lt;br /&gt;
* [[Distance (graph theory)|Distance in graphs]]&lt;br /&gt;
&lt;br /&gt;
*阿尔法中心性&lt;br /&gt;
&lt;br /&gt;
*核心—外围结构&lt;br /&gt;
&lt;br /&gt;
*距离（图理论）图中的距离&lt;br /&gt;
&lt;br /&gt;
==Notes and references==&lt;br /&gt;
&lt;br /&gt;
{{Reflist}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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==Further reading==&lt;br /&gt;
拓展阅读&lt;br /&gt;
* Koschützki, D.; Lehmann, K. A.; Peeters, L.; Richter, S.; Tenfelde-Podehl, D. and Zlotowski, O. (2005) Centrality Indices. In Brandes, U. and Erlebach, T. (Eds.)  ''Network Analysis: Methodological Foundations'', pp.&amp;amp;nbsp;16–61, LNCS 3418, Springer-Verlag.&lt;br /&gt;
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[[Category:Graph theory]]&lt;br /&gt;
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Category:Graph theory&lt;br /&gt;
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分类: 图论&lt;br /&gt;
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[[Category:Graph algorithms]]&lt;br /&gt;
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Category:Graph algorithms&lt;br /&gt;
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分类: 图形算法&lt;br /&gt;
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[[Category:Algebraic graph theory]]&lt;br /&gt;
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Category:Algebraic graph theory&lt;br /&gt;
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分类: 代数图论&lt;br /&gt;
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[[Category:Networks]]&lt;br /&gt;
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Category:Networks&lt;br /&gt;
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分类: 网络&lt;br /&gt;
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[[Category:Network analysis]]&lt;br /&gt;
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Category:Network analysis&lt;br /&gt;
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分类: 网络分析&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Centrality]]. Its edit history can be viewed at [[网络中心性/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E7%BD%91%E7%BB%9C%E4%B8%AD%E5%BF%83%E6%80%A7&amp;diff=19829</id>
		<title>网络中心性</title>
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		<updated>2020-12-09T02:26:04Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* 中心性指数的定义与特性Definition and characterization of centrality indices */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;此词条暂由水流心不竞初译，未经审校，带来阅读不便，请见谅。&lt;br /&gt;
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{{for|the statistical concept|Central tendency}}&lt;br /&gt;
{{Network Science}}&lt;br /&gt;
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In [[graph theory]] and [[network theory|network analysis]], indicators of '''centrality''' identify the most important [[vertex (graph theory)|vertices]] within a graph. Applications include identifying the most influential person(s) in a [[social network]], key infrastructure nodes in the [[Internet]] or [[urban network]]s, and [[super-spreader]]s of disease. Centrality concepts were first developed in [[social network analysis]], and many of the terms used to measure centrality reflect their [[sociology|sociological]] origin.&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
In graph theory and network analysis, indicators of centrality identify the most important vertices within a graph. Applications include identifying the most influential person(s) in a social network, key infrastructure nodes in the Internet or urban networks, and super-spreaders of disease. Centrality concepts were first developed in , and many of the terms used to measure centrality reflect their sociological origin.&lt;br /&gt;
&lt;br /&gt;
They should not be confused with [[node influence metric]]s, which seek to quantify the influence of every node in the network.&lt;br /&gt;
&lt;br /&gt;
They should not be confused with node influence metrics, which seek to quantify the influence of every node in the network.&lt;br /&gt;
&lt;br /&gt;
在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;图论 graph theory &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络分析 network analysis &amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性 centrality &amp;lt;/font&amp;gt;'''指标用于识别图中最重要的顶点。其应用包括在社会网络中识别出最有影响力的个人，在因特网或城市网络中识别出最为关键的基础设施节点，以及识别疾病的超级传播者。中心性的概念最初由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;社会网络分析 social network analysis&amp;lt;/font&amp;gt;'''所发展，因此许多用于衡量中心性的术语都反映出了它们的社会学出身。&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;中心性不应与节点影响度相混淆，后者意在量化网络中每个节点的影响。&lt;br /&gt;
&lt;br /&gt;
==中心性指数的定义与特性Definition and characterization of centrality indices==&lt;br /&gt;
&lt;br /&gt;
Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性指数 centrality indices&amp;lt;/font&amp;gt;'''旨在探寻如何描绘重要节点这一问题。这一问题的答案通常实值函数的形式给出，可根据函数值将图中各节点进行排序，进而确定最为重要的节点。&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
&lt;br /&gt;
The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
&lt;br /&gt;
“重要性”的含义十分广泛，因此导致了许多不同的中心性定义方式。这些不同的定义方式大致可分为两类。&lt;br /&gt;
&lt;br /&gt;
&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important.&amp;lt;ref name=Borgatti2005/&amp;gt; &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt; Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important. Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&lt;br /&gt;
&lt;br /&gt;
“重要性”可以被认为与一种跨网络的流动或传输有关。这允许根据它们认为重要的流类型对中心性进行分类。这两种方法都将中心性划分为不同的类别。进一步的推论是，适用于一个类别的中心性在（推广）应用于另一个类别时往往会“出错”。&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one ([[Centrality#Degree centrality|degree centrality]]) to infinite walks ([[Centrality#Eigenvector centrality|eigenvalue centrality]]).&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=&amp;quot;Benzi2013&amp;quot;&amp;gt;{{cite journal | last1=Benzi | first1=Michele | last2=Klymko| first2=Christine | year=2013 |title= A matrix analysis of different centrality measures |arxiv=1312.6722 | doi=10.1137/130950550 | volume=36 | issue=2 | journal=SIAM Journal on Matrix Analysis and Applications | pages=686–706}}&amp;lt;/ref&amp;gt; The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
&lt;br /&gt;
When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one (degree centrality) to infinite walks (eigenvalue centrality). The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
&lt;br /&gt;
当中心性按照它们对'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 内聚性Cohesiveness&amp;lt;/font&amp;gt;'''的趋近程度来分类时，很明显，大多数中心性都集中在一个类别中。从一个给定顶点开始对步数计数，不同之处只在于行走的定义和计数方式。对该组描述的约束限制，从位置中心（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心度Degree centrality&amp;lt;/font&amp;gt;'''）到单元域（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征中心度Eigenvalue centrality&amp;lt;/font&amp;gt;'''），观察到许多中心性都有这种相似关系，这也许可以解释这些指数之间的高阶相关性。&lt;br /&gt;
&lt;br /&gt;
===Characterization by network flows==&lt;br /&gt;
==网络流特征==&lt;br /&gt;
&lt;br /&gt;
A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at once.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at oe.&lt;br /&gt;
&lt;br /&gt;
一个网络可以被看成是对某种物体流动的路径描述。使基于流的类型和由中心性编码的路径类型（同时）得到表征。一个流可以基于传输，每个不可分割的项目从一个节点到另一个节点，就像一个包裹从配送站送到客户的房子。第二种情况是串行复制，在这种情况下，一个项从源节点被复制到达目标节点。例如通过流言传播信息，以私有方式传播信息，并在流程结束时通知源节点和目标节点。最后一种情况是并行复制，即同时将项目复制到多个链接，就像无线电广播一次性向多个听众提供相同的信息。&lt;br /&gt;
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Likewise, the type of path can be constrained to [[Distance (graph theory)|geodesics]] (shortest paths), [[Glossary of graph theory terms#path|paths]]  (no vertex is visited more than once), [[Glossary of graph theory terms#trail|trails]] (vertices can be visited multiple times, no edge is traversed more than once), or [[Glossary of graph theory terms#walk|walks]] (vertices and edges can be visited/traversed multiple times).&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Likewise, the type of path can be constrained to geodesics (shortest paths), paths  (no vertex is visited more than once), trails (vertices can be visited multiple times, no edge is traversed more than once), or walks (vertices and edges can be visited/traversed multiple times).&lt;br /&gt;
&lt;br /&gt;
同样，路径类型可以被限定为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Distance &amp;lt;/font&amp;gt;'''(最短路径)、路径(对顶点的访问不超过一次)、小径(可以访问多次顶点，没有边被访问超过一次)或者步子(可以访问/遍历多次顶点和边)。&lt;br /&gt;
===Characterization by walk structure===&lt;br /&gt;
==行走结构特征==&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either ''radial'' or ''medial.'' Radial centralities count walks which start/end from the given vertex. The [[Centrality#Degree centrality|degree]] and [[Centrality#Eigenvector centrality|eigenvalue]] centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's [[Centrality#Betweenness centrality|betweenness]] centrality, the number of shortest paths which pass through the given vertex.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either radial or medial. Radial centralities count walks which start/end from the given vertex. The degree and eigenvalue centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's betweenness centrality, the number of shortest paths which pass through the given vertex.&lt;br /&gt;
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可以从中心性的构造方式推导出另一种分类方法。这又分成了两个类。中心点可以是放射状的，也可以是内侧的。从给定顶点开始/结束的径向中心点数。度和特征值中心是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 径向中心Radial centralities&amp;lt;/font&amp;gt;'''的例子，计算长度为一或无穷大的行走的个数。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中间中心性Medial centralities&amp;lt;/font&amp;gt;'''计算通过给定顶点的步数。典型的例子是 弗里曼的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality,&amp;lt;/font&amp;gt;'''，即穿过给定顶点的最短路径的数量。&lt;br /&gt;
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Likewise, the counting can capture either the ''volume'' or the ''length'' of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's [[Centrality#Closeness centrality|closeness]] centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example.&amp;lt;ref name=Borgatti2006/&amp;gt; Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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Likewise, the counting can capture either the volume or the length of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's closeness centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example. Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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同样地，计数可以抓住行走的体积或长度。体积是给定类型的行走的总数。上一段的三个例子就属于这一类。长度则给出从给定顶点到图中其余顶点的距离。弗里曼 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，即从一个给定顶点到所有其他顶点的测地距离，是最著名的例子。请注意，这种分类独立于步行计数的类型(即：步行，小道，路径，测地线)。&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&lt;br /&gt;
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博尔加蒂和埃弗雷特提出，这种类型学为如何最好地比较中心性度量提出了建议。在这个22分类中，放在同一盒子中的中心点足够相似，可以做出合理的选择; 人们可以合理地比较哪个对于给定的应用更好。然而，不同盒子中的度量方法是截然不同的。只有在预先确定哪个类别更适用的情况下，对相对适应性的评估才会发生，这使得比较变得毫无意义。&lt;br /&gt;
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===Radial-volume centralities exist on a spectrum===&lt;br /&gt;
==光谱上存在的径向体积中心==&lt;br /&gt;
The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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步行结构的特征表明，几乎所有广泛使用的中心性都是径向体积的衡量。这得出结论顶点的中心性是与之相关联的顶点中心性的函数。中心性根据如何定义关联而不同。&lt;br /&gt;
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Bonacich showed that if association is defined in terms of [[Glossary of graph theory terms#walk|walks]], then a family of centralities can be defined based on the length of walk considered.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;/&amp;gt; [[Centrality#Degree centrality|Degree centrality]] counts walks of length one, while [[Centrality#Eigenvector centrality|eigenvalue centrality]] counts walks of length infinity. Alternative definitions of association are also reasonable. [[Alpha centrality]] allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich showed that if association is defined in terms of walks, then a family of centralities can be defined based on the length of walk considered. Degree centrality counts walks of length one, while eigenvalue centrality counts walks of length infinity. Alternative definitions of association are also reasonable. Alpha centrality allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich 指出，如果联想是根据行走来定义的，那么可以根据考虑的行走长度来定义一个中心性家族。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''计算长度为1的行走，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征值中心性Eigenvalue centrality  &amp;lt;/font&amp;gt;'''计算长度为无穷大的行走。关联的其他定义也是合理的。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 阿尔法中心性Alpha centrality&amp;lt;/font&amp;gt;'''允许顶点有一个外部影响源。埃斯特拉达的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图中心性Subgraph centrality &amp;lt;/font&amp;gt;'''提出只计算封闭路径(三角形、正方形等)。).&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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这些测量方法的核心是这种现象：图中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵&amp;lt;/font&amp;gt;'''的幂给出了由该幂给出的散步长度的数目。同样，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 矩阵指数Matrix exponential&amp;lt;/font&amp;gt;'''也与给定长度的行走次数密切相关。邻接矩阵的初始转换允许对步行计数的类型进行不同的定义。无论采用哪种方法，顶点的中心性都可以表示为无穷和&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum _ { k = 0} ^ infty a _ { r } ^ { k } beta ^ k &amp;lt;/math &amp;gt; &lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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矩阵能量或者&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum { k = 0} ^ infty frac {(a _ r beta) ^ k }{ k！{/math &amp;gt; &lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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对于矩阵指数函数，其中&lt;br /&gt;
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* &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; is walk length,&lt;br /&gt;
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* &amp;lt;math&amp;gt;A_R&amp;lt;/math&amp;gt; is the transformed adjacency matrix, and&lt;br /&gt;
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* &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; is a discount parameter which ensures convergence of the sum.&lt;br /&gt;
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K为步长，A_R是邻接矩阵的转秩，贝达是保证收敛的折扣参数。&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. [[Alpha centrality]] replaces the adjacency matrix with its [[resolvent formalism|resolvent]]. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to [[Centrality#Degree centrality|degree centrality]]. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to [[Centrality#Eigenvector centrality|eigenvalue centrality]].&amp;lt;ref name=Benzi2013/&amp;gt;&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. Alpha centrality replaces the adjacency matrix with its resolvent. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to degree centrality. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to eigenvalue centrality.&lt;br /&gt;
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博纳奇的一系列措施并没有改变邻接矩阵。阿尔法集中性用它的解决方案替代了邻接矩阵。子图集中性用它的踪迹取代了邻接矩阵。一个令人吃惊的结论是，不管邻接矩阵最初的转变是什么，所有这些方法都有共同的限制行为。随着贝塔系数趋近于零，指数收敛到度中心性。随着贝塔系数接近其最大值，指数收敛到特征值的中心性。&lt;br /&gt;
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===Game-theoretic centrality===&lt;br /&gt;
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=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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上述大多数标准措施的共同特点是，它们通过只关注一个节点本身所扮演的角色来评估确定节点的重要性。然而, 在许多应用中，这种方法是不充分的，因为可能会发生协同作用&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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如果将节点的功能分组考虑。&lt;br /&gt;
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[[File:Game-theoretic centrality.png|Example of game-theoretic centrality]]&lt;br /&gt;
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Example of game-theoretic centrality&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''的例子&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in &amp;lt;ref&amp;gt;Michalak, Aadithya, Szczepański, Ravindran, &amp;amp; Jennings {{ArXiv|1402.0567}}&amp;lt;/ref&amp;gt; uses the [[Shapley value]]. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in  uses the Shapley value. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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例如，考虑阻止流行病的问题。看看上面的网络图像，我们应该给哪些节点接种疫苗？基于前面描述的措施，我们希望识别在疾病传播中最重要的节点。仅仅基于中心的方法，即关注节点的个别特性，可能不是一个好主意。红色方块中的节点，单独不能阻止疾病的传播，但把它们作为一个群体来考虑，我们清楚地看到，如果疾病在节点 &amp;lt; math &amp;gt; v _ 1 &amp;lt;/math &amp;gt; 、 &amp;lt; math &amp;gt; v _ 4 &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; v _ 5 &amp;lt;/math &amp;gt; 中开始，它们就能阻止疾病的传播。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''试图利用博弈论中的工具来研究所描述的问题和机会。本文提出的方法使用了 Shapley 值。由于 Shapley 值计算的时间复杂性，这一领域的大部分工作都集中在实现新的算法和方法，这些算法和方法依赖于网络的特殊拓扑结构或问题的特殊性质。这种方法可以将时间复杂度从指数级降低到多项式级。&lt;br /&gt;
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Similarly, the solution concept [[authority distribution]] (&amp;lt;ref&amp;gt;{{cite journal |last=Hu |first=Xingwei |first2=Lloyd |last2=Shapley |title=On Authority Distributions in Organizations |journal=Games and Economic Behavior |volume=45 |pages=132–170 |year=2003 | doi = 10.1016/s0899-8256(03)00130-1 }}&amp;lt;/ref&amp;gt;) applies the [[Shapley-Shubik power index]], rather than the [[Shapley value]], to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020)&amp;lt;ref&amp;gt;{{cite journal|last=Hu|first=Xingwei|year=2020|volume=7|title=Sorting big data by revealed preference with application to college ranking |journal=Journal of Big Data|doi=10.1186/s40537-020-00300-1|doi-access=free}}&amp;lt;/ref&amp;gt;, such as ranking U.S. colleges.&lt;br /&gt;
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Similarly, the solution concept authority distribution () applies the Shapley-Shubik power index, rather than the Shapley value, to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020), such as ranking U.S. colleges.&lt;br /&gt;
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同样，'''&amp;lt;font color=&amp;quot;#CD32CD&amp;quot;&amp;gt; 加权分布概念的解()The solution concept authority distribution () &amp;lt;/font&amp;gt;'''采用 Shapley-Shubik 幂指数，而不是 Shapley 值来衡量双方之间的直接影响。这种分布确实是一种产生'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征向量中心性Engenvector centrality&amp;lt;/font&amp;gt;'''的类型。它用于对 Hu (2020)中的大数据对象进行排序，比如美国大学排名。&lt;br /&gt;
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== Important limitations ==&lt;br /&gt;
==重要限制==&lt;br /&gt;
Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the [[Krackhardt kite graph]], for which three different notions of centrality give three different choices of the most central vertex.&amp;lt;ref&amp;gt;{{cite journal|title=Assessing the Political Landscape: Structure, Cognition, and Power in Organizations|first=David|last=Krackhardt|authorlink=David Krackhardt|journal=Administrative Science Quarterly|volume=35|issue=2|date=June 1990|pages=342–369|doi=10.2307/2393394|jstor=2393394}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the Krackhardt kite graph, for which three different notions of centrality give three different choices of the most central vertex.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中心性Centrality&amp;lt;/font&amp;gt;'''指标有两个重要的局限性，一个显而易见，另一个则不易察觉。显而易见的局限性是，对于一个应用最优的中心性对于另一个应用常常是次优的。事实上，如果不是这样，我们就不需要这么多不同的中心性。克拉克哈特风筝图为这一现象提供了一个例证，对于这个图，三个不同的中心性概念给出了三个最中心顶点的不同选择。&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices.&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=Borgatti2005/&amp;gt; This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  [[node influence metric]]s to address this problem.&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices. This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  node influence metrics to address this problem.&lt;br /&gt;
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更不易察觉的限制是通常会错误地认为顶点中心性表示顶点的相对重要性。中心性指数被明确地设计来产生一个指出最重要顶点的排名。在刚才提到的限制下，他们做得很好。它们通常不用来测量节点的影响力。最近，网络物理学家开始开发'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;节点影响度量Node influence metrics &amp;lt;/font&amp;gt;'''来解决这个问题。&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying [[Centrality#Freeman centralization|Freeman centralization]] to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt; This approach, however, is seldom seen in practice.{{citation needed|reason=I've come across quite some theoretical studies that indicate otherwise. My suggestion is to remove this sentence, if reasonable citation is not provided.|date=September 2015}}&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying Freeman centralization to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores. This approach, however, is seldom seen in practice.&lt;br /&gt;
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错误有两方面。首先，一个排名只根据顶点的重要性排序，它并不对节点重要性的不同水平进行量化区分。这可以通过将 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;'''应用到中心性度量来缓解，这种度量可以根据节点的不同中心性得分来判断节点的重要性。此外， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;''使人们能够通过比较几个网络的最高中心性得分来比较它们。然而，这种方法在实践中很少见到。&lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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其次，用以(正确地)识别给定网络/应用中最重要顶点的特征并不一定可推广到其余顶点。&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot; /&amp;gt;&amp;lt;ref name=&amp;quot;daSilva2012&amp;quot;&amp;gt;{{cite journal | last1=da Silva|first1=Renato |last2=Viana|first2=Matheus|last3=da F. Costa |first3=Luciano| title=Predicting epidemic outbreak from individual features of the spreaders| journal=J. Stat. Mech.: Theory Exp. | year=2012|volume=2012|pages=P07005|number=7 | doi=10.1088/1742-5468/2012/07/p07005|arxiv=1202.0024|bibcode=2012JSMTE..07..005A}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Bauer2012&amp;quot;&amp;gt;{{cite journal | last1=Bauer|first1=Frank | last2=Lizier|first2=Joseph|title=Identifying influential spreaders and efficiently estimating infection numbers in epidemic models: A walk counting approach| journal=Europhys Lett | year=2012| volume=99| pages=68007|number=6 | doi=10.1209/0295-5075/99/68007|arxiv=1203.0502|bibcode=2012EL.....9968007B}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Sikic2013&amp;quot;&amp;gt;{{ cite journal| last1= Sikic| first1=Mile|last2=Lancic|first2=Alen|last3=Antulov-Fantulin|first3=Nino|last4=Stefanic|first4=Hrvoje| title = Epidemic centrality -- is there an underestimated epidemic impact of network peripheral nodes? |journal = The European Physical Journal B |volume=86 |number=10 |pages=1–13 |year=2013 | doi=10.1140/epjb/e2013-31025-5|arxiv=1110.2558 | bibcode=2013EPJB...86..440S}}&amp;lt;/ref&amp;gt; This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&amp;lt;ref name=&amp;quot;Ghoshal2011&amp;quot;&amp;gt;{{cite journal | last1=Ghoshal | first1= G. | last2= Barabsi |first2= A L | title = Ranking stability and super-stable nodes in complex networks. | journal = Nat Commun | volume =2 | page = 394| year= 2011 | doi=10.1038/ncomms1396 | pmid= 21772265 | bibcode=2011NatCo...2..394G | doi-access= free }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless. This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&lt;br /&gt;
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对于大多数其他网络节点，排名可能是没有意义的。这就解释了为什么，例如，只有谷歌图片搜索的前几个结果以合理的顺序出现。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页排名Pagerank&amp;lt;/font&amp;gt;'''是一个非常不稳定的度量，显示了在跳转参数小的调整之后频繁的秩逆转。&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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虽然中心性指数未能推广到网络的其他部分，乍看起来似乎是违反直觉的，但它直接遵循上述定义。&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot;&amp;gt;{{cite journal |last1= Lawyer |first1= Glenn |year= 2015 |title= Understanding the spreading power of all nodes in a network: a continuous-time perspective |journal=Sci Rep |volume=5|pages=8665|doi=10.1038/srep08665 |pmid=25727453 |pmc=4345333|arxiv=1405.6707|bibcode=2015NatSR...5E8665L}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&lt;br /&gt;
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复杂网络具有异构的拓扑结构。由于最佳度量取决于最重要顶点的网络结构，对于这些顶点最优的度量对于网络的其余部分是次优的。&lt;br /&gt;
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==Degree centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Degree (graph theory)}} &lt;br /&gt;
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[[File:6 centrality measures.png|thumb|right|300px|Examples of A) [[Betweenness centrality]], B) [[Closeness centrality]], C) [[Eigenvector centrality]], D) [[Degree centrality]], E) [[Centrality#Harmonic centrality|Harmonic centrality]] and F) [[Katz centrality]] of the same graph.]]&lt;br /&gt;
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Examples of A) [[Betweenness centrality, B) Closeness centrality, C) Eigenvector centrality, D) Degree centrality, E) Harmonic centrality and F) Katz centrality of the same graph.]]&lt;br /&gt;
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实例 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; a)[中介中心性A) [[Betweenness centrality,b)紧密中心性，B) Closeness centrality, c)特征向量中心性，C) Eigenvector centrality, d)度中心性，D) Degree centrality, e)调和中心性，E) Harmonic centrality andf) 卡兹Katz 中心性]F) Katz centrality .]]&amp;lt;/font&amp;gt;'''&lt;br /&gt;
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Historically first and conceptually simplest is '''degree centrality''', which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely [[indegree]] and [[outdegree]]. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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Historically first and conceptually simplest is degree centrality, which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely indegree and outdegree. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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历史上最简单的概念是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''，它定义为一个节点上发生的链接数量(即一个节点拥有的关系数量)。度可以根据节点捕获流经网络的任何东西(例如病毒或某些信息)的直接风险来解释。在有向网络的情况下(其中联系有方向) ，我们通常定义两个独立的度量，即 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度 Outdegree&amp;lt;/font&amp;gt;'''。因此，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度indegree&amp;lt;/font&amp;gt;'''是指向该节点的关系数，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度outdegree&amp;lt;/font&amp;gt;'''是指该节点指向其他节点的关系数。当关系与一些积极的方面如友谊或合作有关时， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''通常被解释为一种形式的受欢迎，而 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度Indegree&amp;lt;/font&amp;gt;'''则被解释为合群。&lt;br /&gt;
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The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
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The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
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对于给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边，度的中心性定义为&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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Calculating degree centrality for all the nodes in a graph takes [[big theta|&amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt;]] in a [[dense matrix|dense]] [[adjacency matrix]] representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a [[sparse matrix]] representation.&lt;br /&gt;
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Calculating degree centrality for all the nodes in a graph takes &amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt; in a dense adjacency matrix representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a sparse matrix representation.&lt;br /&gt;
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计算一个图中所有节点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''需要在图的稠密'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵Adjacency matrix &amp;lt;/font&amp;gt;'''表示中使用 Theta (v ^ 2) &amp;lt;/math &amp;gt; ，而在稀疏矩阵表示中使用 Theta (e) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of ''graph centralization''.&amp;lt;ref&amp;gt;Freeman, Linton C. &amp;quot;Centrality in social networks conceptual clarification.&amp;quot; Social networks 1.3 (1979): 215–239.&amp;lt;/ref&amp;gt; Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
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The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of graph centralization. Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
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节点级中心性的定义可以扩展到整个图，在这种情况下，我们指的是图的集中性。设 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 为 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''最高的节点。让 &amp;lt; math &amp;gt; x: = (y，z) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; | y | &amp;lt;/math &amp;gt; 节点连接图，最大化下列数量(&amp;lt; math &amp;gt; y * &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 中度最高的节点) :&lt;br /&gt;
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:&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; h = sum ^ { | y | }{ j = 1}[ c _ d (y *)-c _ d (y _ j)] &amp;lt;/math &amp;gt; &lt;br /&gt;
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Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
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Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
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相应地，图形 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''如下:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ h } &amp;lt;/math &amp;gt; &lt;br /&gt;
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The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a [[star graph]]), and in this case&lt;br /&gt;
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The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a star graph), and in this case&lt;br /&gt;
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当图形 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 包含一个所有其他节点都连接的中心节点(一个星形图)时，&amp;lt; math &amp;gt; h &amp;lt;/math &amp;gt; 的值最大化，在这种情况下&lt;br /&gt;
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:&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
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(n-1)-1) = n ^ 2-3n + 2&lt;br /&gt;
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So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
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So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
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所以，对于任意的图 &amp;lt; math &amp;gt; g: = (v，e) ，&amp;lt;/math &amp;gt; &lt;br /&gt;
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:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ | v | ^ 2-3 | v | + 2} &amp;lt;/math &amp;gt;&lt;br /&gt;
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==Closeness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Closeness centrality}}In a [[Connected component (graph theory)|connected]] [[Graph (discrete mathematics)|graph]], the [[Normalization (statistics)|normalized]] '''closeness centrality''' (or '''closeness''') of a node is the average length of the [[Shortest path problem|shortest path]] between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
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In a connected graph, the normalized closeness centrality (or closeness) of a node is the average length of the shortest path between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
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在连通图中，节点的标准'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''(或贴近性)是节点与图中所有其他节点之间最短路径的平均长度。因此，一个节点越是中心，它就越接近所有其他节点。&lt;br /&gt;
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Closeness was defined by [[Alex Bavelas]] (1950) as the [[Multiplicative inverse|reciprocal]] of the '''farness''',&amp;lt;ref&amp;gt;Alex Bavelas. Communication patterns in task-oriented groups. ''J. Acoust. Soc. Am'', '''22'''(6):725–730, 1950.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;{{cite journal|year=1966|title=The centrality index of a graph|url=|journal=Psychometrika|volume=31|issue=4|pages=581–603|doi=10.1007/bf02289527|pmid=5232444|hdl=10338.dmlcz/101401|last1=Sabidussi|first1=G|hdl-access=free}}&amp;lt;/ref&amp;gt; that is:&lt;br /&gt;
&lt;br /&gt;
Closeness was defined by Alex Bavelas (1950) as the reciprocal of the farness, that is:&lt;br /&gt;
&lt;br /&gt;
亚历克斯 · 巴维拉斯(1950)将亲密度定义为相对于距离的倒数，即:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
C (x) = frac {1}{ sum _ y d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the [[Distance (graph theory)|distance]] between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the distance between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; d (y，x) &amp;lt;/math &amp;gt; 是顶点 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; 之间的距离。然而，当谈到'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''时，人们通常会提到它的标准化形式，一般是以前的公式乘以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; ，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。这种调整允许比较不同大小图形的节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Taking distances ''from'' or ''to'' all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in [[directed graph]]s (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
&lt;br /&gt;
Taking distances from or to all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in directed graphs (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
&lt;br /&gt;
从所有其他节点或到所有其他节点的距离在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 无向图Undirected graphs&amp;lt;/font&amp;gt;'''中是不相关的，但是在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 有向图Directed graphs&amp;lt;/font&amp;gt;'''中可能产生完全不同的结果(例如:一个网站可以从传出链接获得高的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，而从传入链接获得低的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''）。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
===Harmonic centrality===&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the '''harmonic centrality''' reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the harmonic centrality reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
在一个(不一定是连通的)图中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''反转了'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''定义中的和互反运算:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h (x) = sum { y neq x } frac {1}{ d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; 1/d (y，x) = 0 &amp;lt;/math &amp;gt; if there is no path from &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; to &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 。调和中心性可以通过除以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; 来标准化，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Harmonic centrality was proposed by [[Massimo Marchiori|Marchiori]] and [[Vito Latora|Latora]] (2000)&amp;lt;ref name=&amp;quot;marchiorilatora2000&amp;quot;&amp;gt;{{citation| journal = Physica A: Statistical Mechanics and Its Applications  | last1 = Marchiori | first1 = Massimo | last2 = Latora | first2 = Vito | year = 2000 | volume = 285 | issue = 3–4 | pages = 539–546 | title = Harmony in the small-world | doi=10.1016/s0378-4371(00)00311-3| arxiv = cond-mat/0008357 | bibcode = 2000PhyA..285..539M }}&amp;lt;/ref&amp;gt; and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot;&amp;lt;ref&amp;gt;{{cite journal|first1=Anthony|last1=Dekker|title=Conceptual Distance in Social Network Analysis|journal=Journal of Social Structure|volume=6|issue=3|year=2005|url=http://www.cmu.edu/joss/content/articles/volume6/dekker/index.html}}&amp;lt;/ref&amp;gt; and by Rochat (2009).&amp;lt;ref&amp;gt;{{cite conference  | author = Yannick Rochat  | title = Closeness centrality extended to unconnected graphs: The harmonic centrality index | conference = Applications of Social Network Analysis, ASNA 2009 | url = http://infoscience.epfl.ch/record/200525/files/%5bEN%5dASNA09.pdf }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Harmonic centrality was proposed by Marchiori and Latora (2000) and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot; and by Rochat (2009).&lt;br /&gt;
&lt;br /&gt;
调和中心性是由 Marchiori 和 Latora (2000)提出的，然后是 Dekker (2005)独立提出的，使用的名称是“有价值的中心性” ，Rochat (2009)。&lt;br /&gt;
&lt;br /&gt;
==Betweenness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Betweenness centrality}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Graph betweenness.svg|240px|right|thumb|Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.]]&lt;br /&gt;
&lt;br /&gt;
Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.&lt;br /&gt;
&lt;br /&gt;
色调(从红色 = 0到蓝色 = max)表示节点之间的距离。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
'''Betweenness''' is a centrality measure of a [[vertex (graph theory)|vertex]] within a [[Graph (discrete mathematics)|graph]] (there is also [[edge (graph theory)|edge]] betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by [[Linton Freeman]]&amp;lt;ref name=&amp;quot;freeman1977&amp;quot;&amp;gt;{{cite journal |last1 = Freeman |first1 = Linton | year=1977| title = A set of measures of centrality based upon betweenness | journal = Sociometry| volume=40|issue = 1 | pages=35–41 | doi=10.2307/3033543|jstor = 3033543 }}&amp;lt;/ref&amp;gt; In his conception, vertices that have a high probability to occur on a randomly chosen [[shortest path problem|shortest path]] between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
&lt;br /&gt;
Betweenness is a centrality measure of a vertex within a graph (there is also edge betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by Linton Freeman In his conception, vertices that have a high probability to occur on a randomly chosen shortest path between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
&lt;br /&gt;
中介性是图中顶点的中心性度量(也有边中介性，这里没有讨论)。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''量化了一个节点沿着其他两个节点之间的最短路径充当桥梁的次数。在林顿 · 弗里曼的概念中，在两个随机选择的顶点之间随机选择的最短路径上出现概率高的顶点具有很高的中介性。&lt;br /&gt;
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&lt;br /&gt;
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The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
&lt;br /&gt;
The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
&lt;br /&gt;
在一个图 &amp;lt; math &amp;gt; g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的顶点之间的距离计算如下:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
# For each pair of vertices (''s'',''t''), compute the [[Shortest path problem|shortest paths]] between them.&lt;br /&gt;
&lt;br /&gt;
 For each pair of vertices (s,t), compute the shortest paths between them.&lt;br /&gt;
&lt;br /&gt;
对于每一对顶点(s，t) ，计算它们之间的最短路径。&lt;br /&gt;
&lt;br /&gt;
# For each pair of vertices (''s'',''t''), determine the fraction of shortest paths that pass through the vertex in question (here, vertex ''v'').&lt;br /&gt;
&lt;br /&gt;
 For each pair of vertices (s,t), determine the fraction of shortest paths that pass through the vertex in question (here, vertex v).&lt;br /&gt;
&lt;br /&gt;
对于每对顶点(s，t) ，确定通过该顶点(这里是顶点 v)的最短路径的分数。&lt;br /&gt;
&lt;br /&gt;
# Sum this fraction over all pairs of vertices (''s'',''t'').&lt;br /&gt;
&lt;br /&gt;
 Sum this fraction over all pairs of vertices (s,t).&lt;br /&gt;
&lt;br /&gt;
对所有顶点对(s，t)求这个分数的和。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
More compactly the betweenness can be represented as:&amp;lt;ref name=&amp;quot;brandes&amp;quot;&amp;gt;{{cite journal |last1 = Brandes |first1 = Ulrik | year=2001 |title = A faster algorithm for betweenness centrality  | journal = Journal of Mathematical Sociology| volume=25|issue = 2 | pages=163–177| url = http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.11.2024 | accessdate = October 11, 2011| format = PDF | doi=10.1080/0022250x.2001.9990249|citeseerx = 10.1.1.11.2024 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
More compactly the betweenness can be represented as:&lt;br /&gt;
&lt;br /&gt;
更确切地说，两者之间的关系可以表示为:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
{ math &amp;gt; c _ b (v) = sum _ { s neq v neq t in v } frac { sigma _ st }(v)}{ sigma _ st } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including ''v'', which for [[Digraph (mathematics)|directed graphs]] is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected [[Star (graph theory)|star graph]], the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including v, which for directed graphs is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected star graph, the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; sigma { st } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { st }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径数。有向图是 &amp;lt; math &amp;gt; (n-1)(n-2) &amp;lt;/math &amp;gt; ，无向图是 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; 。例如，在一个无向星图中，中心顶点(包含在每个可能的最短路径中)的中介性为 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; (1，如果标准化) ，而叶子(包含在没有最短路径中)的中介性为0。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires [[Big O notation|&amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt;]] time with the [[Floyd–Warshall algorithm]]. However, on sparse graphs, [[Johnson's algorithm]] may be more efficient, taking [[Big O notation|&amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt;]] time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm&amp;lt;ref name=brandes/&amp;gt; which takes [[Big O notation|&amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt;]] time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&amp;lt;ref name=&amp;quot;brandes&amp;quot; /&amp;gt;&lt;br /&gt;
&lt;br /&gt;
From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires &amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt; time with the Floyd–Warshall algorithm. However, on sparse graphs, Johnson's algorithm may be more efficient, taking &amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt; time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm which takes &amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt; time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&lt;br /&gt;
&lt;br /&gt;
从计算的角度来看，图中所有顶点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介和紧密中心性Betweenness and Closeness centralities&amp;lt;/font&amp;gt;'''都涉及到计算图中所有顶点对之间的最短路径，这就需要用 Floyd-Warshall 算法计算时间。然而，对于稀疏图，约翰逊算法的效率可能更高，采用 &amp;lt; math &amp;gt; o (v ^ 2 log v + v e) &amp;lt;/math &amp;gt; 时间。在不加权图的情况下，可以用 Brandes 的算法进行计算，该算法需要 &amp;lt; math &amp;gt; o (v e) &amp;lt;/math &amp;gt; 时间。一般情况下，这些算法假定图是无向的，并且连通图中允许有圈和多条边。当专门处理网络图时，图通常没有环或多条边来维持简单的关系(其中的边表示两个人或顶点之间的联系)。在这种情况下，使用 Brandes 的算法将最终的中心性分数除以2来计算每条被重复计算的最短路径。&lt;br /&gt;
&lt;br /&gt;
==Eigenvector centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Eigenvector centrality}}&lt;br /&gt;
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'''Eigenvector centrality''' (also called '''eigencentrality''') is a measure of the influence of a [[node (networking)|node]] in a [[network (mathematics)|network]]. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&amp;lt;ref&amp;gt;{{cite journal|title = The mathematics of networks|url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf|author = M. E. J. Newman|accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;/&amp;gt; [[Google]]'s [[PageRank]] and the [[Katz centrality]] are variants of the eigenvector centrality.&amp;lt;ref name=&amp;quot;ams&amp;quot;&amp;gt;{{Cite web | url=http://www.ams.org/samplings/feature-column/fcarc-pagerank | title=American Mathematical Society}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Eigenvector centrality (also called eigencentrality) is a measure of the influence of a node in a network. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''(也称为特征中心性)是衡量网络中节点影响的一个指标。它将相对得分分配给网络中的所有节点，这是基于这样一个概念: 与得分较高的节点相比，与得分较低的节点相同的连接对所涉及的节点的得分贡献更大。&lt;br /&gt;
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=== Using the adjacency matrix to find eigenvector centrality ==&lt;br /&gt;
==使用'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''发现'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the [[adjacency matrix]], i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
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For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the adjacency matrix, i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
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对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 让 &amp;lt; math &amp;gt; a = (a { v，t }) &amp;lt;/math &amp;gt; 成为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''，即。如果顶点 &amp;lt; math &amp;gt; &amp;gt; v &amp;lt;/math &amp;gt; 与 math &amp;gt; t &amp;lt;/math &amp;gt; 相连，而 &amp;lt; math &amp;gt; a { v，t } = 0 &amp;lt;/math &amp;gt; 否则。顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分可以定义为:&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
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在 m (v)} x _ t = frac {1}{ lambda } sum { t in g } a { v，t } x _ t &amp;lt;/math &amp;gt; &lt;br /&gt;
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where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the [[eigenvector]] equation&lt;br /&gt;
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where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the eigenvector equation&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; m (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 和 &amp;lt; math &amp;gt; &amp;gt; lambda &amp;lt;/math &amp;gt; 的邻居集合。通过一个小的重新排列，这可以被重写成向量符号，作为特征向量方程&lt;br /&gt;
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:&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
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[ math &amp;gt; mathbf { Ax } = { lambda } mathbf { x } &amp;lt;/math &amp;gt; &lt;br /&gt;
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In general, there will be many different [[eigenvalue]]s &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the [[Perron–Frobenius theorem]]. This greatest eigenvalue results in the desired centrality measure.&amp;lt;ref&amp;gt;{{cite journal  | author = M. E. J. Newman  | title = The mathematics of networks  | url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf  | accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt; The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices ''n''. [[Power iteration]] is one of many [[eigenvalue algorithm]]s that may be used to find this dominant eigenvector.&amp;lt;ref name=&amp;quot;ams&amp;quot; /&amp;gt; Furthermore, this can be generalized so that the entries in ''A'' can be real numbers representing connection strengths, as in a [[stochastic matrix]].&lt;br /&gt;
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In general, there will be many different eigenvalues &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the Perron–Frobenius theorem. This greatest eigenvalue results in the desired centrality measure. The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices n. Power iteration is one of many eigenvalue algorithms that may be used to find this dominant eigenvector. Furthermore, this can be generalized so that the entries in A can be real numbers representing connection strengths, as in a stochastic matrix.&lt;br /&gt;
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一般情况下，存在许多不同的特征值，对于这些特征值存在一个非零特征向量解。由于邻接矩阵中的条目是非负的，所以由 Perron-弗罗贝尼乌斯定理得出，它有一个实的和正的唯一最大特征值。由这个最大的特征值得出期望的中心性度量。相关特征向量的 &amp;lt; math &amp;gt; v ^ { th } &amp;lt;/math &amp;gt; 分量给出了网络中顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分。特征向量只定义了一个公共因子，所以只有顶点中心的比例是明确定义的。要定义一个绝对分数，必须对特征向量进行标准化，例如，使所有顶点的和为1或顶点的总数n。此外，这可以通用，使得 a 中的条目可以是表示连接强度的真实数字，就像'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 随机矩阵Stochastic matrix&amp;lt;/font&amp;gt;'''中一样。&lt;br /&gt;
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==Katz centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Katz centrality}}&lt;br /&gt;
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'''Katz centrality'''&amp;lt;ref&amp;gt;Katz, L. 1953. A New Status Index Derived from Sociometric Index. Psychometrika, 39–43.&amp;lt;/ref&amp;gt; is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
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Katz centrality is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''是度中心性的推广。度中心性度量的是直接邻居的数量，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''度量的是通过一条路径可以连接的所有节点的数量，而远处节点的贡献会受到'''&amp;lt;font color=&amp;quot;#32CD32&amp;quot;&amp;gt; '削弱（惩罚？）Penalized&amp;lt;/font&amp;gt;''。在数学上，它被定义为&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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[数学][数学]&lt;br /&gt;
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where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; (0,1) &amp;lt;/math &amp;gt; 中的衰减因子。&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''可以看作是特征向量中心性的变体。Katz 中心性的另一种形式是&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
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(x _ j + 1) &lt;br /&gt;
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Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
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Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
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与特征向量中心性的表达式相比，&amp;lt; math &amp;gt; x _ j &amp;lt;/math &amp;gt; 被 &amp;lt; math &amp;gt; x _ j + 1所代替&lt;br /&gt;
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It is shown that&amp;lt;ref&amp;gt;{{cite journal | last1 = Bonacich | first1 = P | year = 1991 | title = Simultaneous group and individual centralities | url = | journal = Social Networks | volume = 13 | issue = 2| pages = 155–168 | doi=10.1016/0378-8733(91)90018-o}}&amp;lt;/ref&amp;gt; the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
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It is shown that the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
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结果表明，主特征向量(与 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; ，邻接矩阵的最大特征值相关)是 Katz 中心性的极限，因为 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 接近 &amp;lt; math &amp;gt; tfrac {1}{ lambda } &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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== PageRank centrality ==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页分布中心性PageRank&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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{{main|PageRank}}'''[[PageRank]]''' satisfies the following equation&lt;br /&gt;
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PageRank satisfies the following equation&lt;br /&gt;
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PageRank满足下面的等式&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
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1-alpha { n } ，&amp;lt;/math &amp;gt; &lt;br /&gt;
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where&lt;br /&gt;
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where&lt;br /&gt;
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其中&lt;br /&gt;
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:&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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[ math &amp;gt; l (j) = sum { i } a { ji } &amp;lt;/math &amp;gt; &lt;br /&gt;
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is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&amp;lt;ref&amp;gt;[http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf How does Google rank webpages?] {{webarchive | url= https://web.archive.org/web/20120131083328/http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf |date=January 31, 2012 }} 20Q: About Networked Life&amp;lt;/ref&amp;gt;&lt;br /&gt;
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is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&lt;br /&gt;
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是节点 &amp;lt; math &amp;gt; j &amp;lt;/math &amp;gt; (或有向图中出站链接的数量)的邻居数量。与特征向量中心性和 Katz 中心性相比，尺度因子 &amp;lt; math &amp;gt; l (j) &amp;lt;/math &amp;gt; 是一个主要的区别。PageRank 和特征向量中心性的另一个区别是 PageRank 向量是一个左手特征向量(注意因子 &amp;lt; math &amp;gt; a _ { ji } &amp;lt;/math &amp;gt; 具有相反的索引)。&lt;br /&gt;
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==Percolation centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&amp;lt;ref name=&amp;quot;piraveenan2013&amp;quot;&amp;gt;{{cite journal |last1 = Piraveenan |first1 = M. |last2 = Prokopenko |first2 = M.|last3 = Hossain|first3 = L. |year=2013| title = Percolation Centrality: Quantifying Graph-Theoretic Impact of Nodes during Percolation in Networks | journal = PLOS One | volume=8 | issue=1 | doi=10.1371/journal.pone.0053095 | pages=e53095 | pmid=23349699 | pmc=3551907| bibcode=2013PLoSO...853095P }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&lt;br /&gt;
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在复杂网络中，存在大量的中心性度量来确定单个节点的“重要性”。然而，这些度量单纯从拓扑学的角度来量化节点的重要性，节点的值并不以任何方式依赖于节点的状态。不管网络动态如何，它都保持不变。即使对于加权的两者之间的度量也是如此。然而，一个节点可能很好地位于'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''或其他中心性度量的中心位置，但可能不是位于有过滤的网络的上下文中的中心位置。在许多情况下，复杂网络中都会出现“传染”现象。例如，病毒或细菌感染可以通过人们的社交网络传播，也就是所谓的接触网络。还可以在更高的抽象层次上考虑疾病的传播问题，设想通过公路、铁路或空中连接起来的城镇或人口中心网络。计算机病毒可以通过计算机网络传播。关于商业活动和交易的谣言或新闻也可以通过人们的社交网络传播。在所有这些情况下，一种“传染病”在一个复杂网络的链接上传播，随着它的传播，无论是可恢复的还是不可恢复的，都会改变节点的“状态”。例如，在流行病学方案中，随着感染扩散，个人从”易感”状态转变为”受感染”状态。在上面的例子中，随着传染的扩散，每个节点可以采取的状态可以是二进制的(例如接收/没有接收到一条新闻)、离散的(易感/受感染/康复) ，甚至是连续的(例如一个城镇中受感染的人的比例) 。这些情景的共同特点是，传染的扩散导致网络中节点状态的改变。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''（PC)就是基于这个思想而提出的，它特别地衡量了节点在协助网络渗滤方面的重要性。这项措施是由 piraveanan 等人提出的。&lt;br /&gt;
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'''Percolation centrality''' is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
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Percolation centrality is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''定义为在给定时间内一个给定节点的过滤路径的比例。“渗滤路径”是一对节点之间的最短路径，其中源节点被渗滤(例如，被感染)。目标节点可以是过滤的或非过滤的，或处于部分过滤状态。&lt;br /&gt;
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:&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; PC ^ t (v) = frac {1}{ N-2} sum { s neq v neq r } frac { sigma { sr }(v)}{ sigma { sr }} frac { x ^ t }{ sum {[{ x ^ t } i }}}]}}-{ x ^ t }{ v } &amp;lt;/math &amp;gt; &lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; σ { sr } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; r &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { sr }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径的总数。在时间 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 时，节点的过滤状态用 &amp;lt; math &amp;gt; { x ^ t } _ i &amp;lt;/math &amp;gt; 表示，两个特殊情况是当 &amp;lt; math &amp;gt; { x ^ t } _ i = 0 &amp;lt;/math &amp;gt; 表示在时间上是非过滤状态，而当 &amp;lt; math &amp;gt; &amp;lt; x ^ t &amp;lt;/math &amp;gt; i = 1 &amp;lt;/math &amp;gt; 表示在时间上是完全过滤状态。两者之间的值表示部分过滤状态(例如，在一个城镇网络中，这是该城镇感染者的百分比)。&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in [[Big O notation|&amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt;]] time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is [[Big O notation|&amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;]].&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in &amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt; time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is &amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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渗流路径的权重取决于分配给源节点的渗流水平，前提是源节点的渗流水平越高，源节点的路径就越重要。因此，位于源自高渗滤节点的最短路径上的节点可能对渗滤更为重要。PC 的定义也可以扩展到包括目标节点的权重。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''计算运行在 &amp;lt; math &amp;gt; o (NM) &amp;lt;/math &amp;gt; 时间，采用了 Brandes 快速算法的有效实现，如果计算需要考虑目标节点的权重，最坏情况下时间为 &amp;lt; math &amp;gt; o (n ^ 3) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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==Cross-clique centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 交叉团中心性Cross-clique centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
'''Cross-clique centrality''' of a single node in a complex graph determines the connectivity of a node to different [[clique (graph theory)|clique]]s. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in &amp;lt;ref name=&amp;quot;xssworms&amp;quot;&amp;gt;{{cite journal |last1 = Faghani|first1 = Mohamamd Reza| year=2013| title = A Study of XSS Worm Propagation and Detection Mechanisms in Online Social Networks | journal = IEEE Transactions on Information Forensics and Security|volume = 8|issue = 11|pages = 1815–1826|doi = 10.1109/TIFS.2013.2280884}}&amp;lt;/ref&amp;gt; but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
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Cross-clique centrality of a single node in a complex graph determines the connectivity of a node to different cliques. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in  but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
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复杂图中单个节点的跨团中心性决定了一个节点与不同团的连通性。具有高度跨团连通性的节点有利于信息或疾病在图中的传播。团是一种'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图Subgraphs&amp;lt;/font&amp;gt;'''，团中的每个节点都与团中的其他节点相连。对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边的交叉团连通性，定义为 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; x (v) &amp;lt;/math &amp;gt; 其中 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 所属的顶点团数。这个测度应用日久，但是在1998年由 Everett 和 Borgatti 首次提出，他们称之为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 派系重叠中心性Clique-overlap centrality&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Freeman centralization==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心度Freeman centralization&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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The '''centralization''' of any network is a measure of how central its most central node is in relation to how central all the other nodes are.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;&amp;gt;{{citation | journal = Social Networks | last1 = Freeman | first1 = Linton C. | year = 1979 | volume = 1 | issue = 3 | pages = 215–239 | title = centrality in social networks: Conceptual clarification | url = http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | doi = 10.1016/0378-8733(78)90021-7 | citeseerx = 10.1.1.227.9549 | access-date = 2014-07-31 | archive-url = https://web.archive.org/web/20160222033108/http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | archive-date = 2016-02-22 | url-status = dead }}&amp;lt;/ref&amp;gt; Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
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The centralization of any network is a measure of how central its most central node is in relation to how central all the other nodes are. Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
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任何网络的集中度都是衡量其最核心的节点相对于其他所有节点的集聚程度的标准。集中度的度量方法是: (a)计算网络中最中心的节点与所有其他节点之间的中心性差异之和; (b)将这个数量除以理论上相同规模的任何网络中这种差异之和的最大值。因此，每个中心性度量都可以有自己的集中性度量。正式定义，如果 &amp;lt; math &amp;gt; c _ x (p _ i) &amp;lt;/math &amp;gt; 是点 &amp;lt; math &amp;gt; i &amp;lt;/math &amp;gt; 的中心性度量，如果 &amp;lt; math &amp;gt; c _ x (p _ *) &amp;lt;/math &amp;gt; 是网络中最大的中心性度量，如果:&lt;br /&gt;
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:&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; max sum { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i) &amp;lt;/math &amp;gt; &lt;br /&gt;
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is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;&lt;br /&gt;
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is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&lt;br /&gt;
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对于任何具有相同节点数的图来说，点中心性的最大差异是:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; c _ x = frac { sum _ { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i)}{ max sum _ { i = 1 ^ { n } c _ x (p _ *)-c _ x (p _ i)} . &amp;lt;/math &amp;gt;&lt;br /&gt;
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== Dissimilarity based centrality measures ==&lt;br /&gt;
==基于相异性的中心性度量==&lt;br /&gt;
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[[File:Srep17095-f1.jpg|thumbnail|In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.]]&lt;br /&gt;
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In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.&lt;br /&gt;
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在图示的网络中，绿色节点和红色节点最不相似，因为它们之间不共享相邻节点。因此，绿色的节点比灰色的节点对中心性的贡献更大，因为红色的节点只能通过绿色访问蓝色的节点，而灰色的节点对于红色的节点是多余的，因为它可以直接访问每个灰色的节点，而不需要任何中介。&lt;br /&gt;
&lt;br /&gt;
In order to obtain better results in the ranking of the nodes of a given network,  in &amp;lt;ref&amp;gt;{{Cite journal|title = Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|journal = Scientific Reports|date = 2015-11-25|pmc = 4658528|pmid = 26603652|volume = 5|doi = 10.1038/srep17095|first = A. J.|last = Alvarez-Socorro|first2 = G. C.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz|pages=17095|bibcode = 2015NatSR...517095A}}&amp;lt;/ref&amp;gt; are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with [[eigenvector centrality]], calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
&lt;br /&gt;
In order to obtain better results in the ranking of the nodes of a given network,  in  are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with eigenvector centrality, calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
&lt;br /&gt;
为了在给定网络节点的排序中获得更好的结果，在复杂网络中使用了相异性度量(特定于分类和数据挖掘理论)来丰富中心性度量。特征向量中心性通过求解特征值问题来计算每个节点的中心性&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
数学，数学&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary [[Matrix similarity|dissimilarity]] matrix, defined through a dissimilitary measure, e.g., [[Jaccard index|Jaccard]] dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary dissimilarity matrix, defined through a dissimilitary measure, e.g., Jaccard dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
这里 &amp;lt; math &amp;gt; w { ij } = a { ij } d { ij } &amp;lt;/math &amp;gt; (coordinate-to-coordinate product)和 &amp;lt; math &amp;gt; d { ij } &amp;lt;/math &amp;gt; 是一个任意的不相似矩阵，通过一个双重军事度量来定义，例如，Jaccard 由&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1-dfrac { | v ^ { + }(i) cap v ^ { + }(j) | }{ | v ^ { + }(i) cup v ^ { + }(j) | } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
&lt;br /&gt;
Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
&lt;br /&gt;
这种度量允许我们量化每个节点对给定节点中心性的拓扑贡献(这就是为什么我们称之为贡献中心性) ，对那些相异性较大的节点有更多的权重/相关性，因为这些节点允许给定的节点访问那些它们自己不能直接访问的节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the [[Perron–Frobenius theorem]] to ensure that the above problem has a unique solution for ''λ'' = ''λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt;'' with '''c''' non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
&lt;br /&gt;
Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the Perron–Frobenius theorem to ensure that the above problem has a unique solution for λ = λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt; with c non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
&lt;br /&gt;
值得注意的是，&amp;lt; math &amp;gt; w &amp;lt;/math &amp;gt; 是非负的，因为 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; d &amp;lt;/math &amp;gt; 都是非负矩阵，所以我们可以使用 Perron 弗罗贝尼乌斯定理来确保上述问题对于 c 非负的 = &amp;lt; sub &amp;gt; max &amp;lt;/sub &amp;gt; 有唯一的解，这样我们就可以推断出网络中每个节点的中心性。因此，i-th 节点的中心性为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1{ n } sum { j = 1} ^ { n } w { ij } c { j } ，，，，，j = 1，cdots，n &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in &amp;lt;ref&amp;gt;{{Cite web|url = http://www.nature.com/article-assets/npg/srep/2015/151125/srep17095/extref/srep17095-s1.pdf|title = Supplementary Information for Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|date = |website = |publisher = Nature Publishing Group|last = Alvarez-Socorro|first = A.J.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz}}&amp;lt;/ref&amp;gt; obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in  obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是网络中的节点数。几个不同的措施和网络进行了测试，以获得在研究案例的改善的结果。&lt;br /&gt;
&lt;br /&gt;
==Extensions==&lt;br /&gt;
==扩展==&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality&amp;lt;ref&amp;gt;{{cite journal | last1 = Braha | first1 = D. | last2 = Bar-Yam | first2 = Y. | year = 2006 | title = From Centrality to Temporary Fame: Dynamic Centrality in Complex Networks | url = | journal = Complexity | volume = 12 | issue = 2| pages = 59–63 | doi=10.1002/cplx.20156| arxiv = physics/0611295 | bibcode = 2006Cmplx..12b..59B }}&amp;lt;/ref&amp;gt; in the context of time-dependent and temporal networks.&amp;lt;ref&amp;gt;{{cite journal | last1 = Hill | first1 = S.A. | last2 = Braha | first2 = D. | year = 2010 | title = Dynamic Model of Time-Dependent Complex Networks | url = | journal = Physical Review E | volume = 82 | issue = 4| page = 046105 | doi=10.1103/physreve.82.046105| pmid = 21230343 | arxiv = 0901.4407 | bibcode = 2010PhRvE..82d6105H }}&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Gross, T. and Sayama, H. (Eds.). 2009. ''Adaptive Networks: Theory, Models and Applications.'' Springer.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Holme, P. and Saramäki, J. 2013. ''Temporal Networks.'' Springer.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality in the context of time-dependent and temporal networks.&lt;br /&gt;
&lt;br /&gt;
经验和理论研究已经将静态网络中的中心性概念扩展到时间依赖网络和时间网络中的动态中心性。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&amp;lt;ref&amp;gt;{{cite journal | last1 = Opsahl | first1 = Tore | last2 = Agneessens | first2 = Filip | last3 = Skvoretz | first3 = John | title = Node centrality in weighted networks: Generalizing degree and shortest paths | doi = 10.1016/j.socnet.2010.03.006 | year = 2010 | pages = 245–251 | volume = 32 | journal = Social Networks | url = http://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | issue = 3 | access-date = 2010-04-23 | archive-url = https://web.archive.org/web/20180226080331/https://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | archive-date = 2018-02-26 | url-status = dead }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&lt;br /&gt;
&lt;br /&gt;
对加权网络的推广，见 Opsahl 等人。(2010).&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, '''group betweenness''' centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&amp;lt;ref name=&amp;quot;group1&amp;quot;&amp;gt;Everett, M. G. and Borgatti, S. P. (2005). Extending centrality. In P. J. Carrington, J. Scott and S. Wasserman (Eds.), ''Models and methods in social network analysis'' (pp. 57–76). New York: Cambridge University Press.&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;group2&amp;quot;&amp;gt;Puzis, R., Yagil, D., Elovici, Y., Braha, D. (2009).[http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf Collaborative attack on Internet users’ anonymity] {{Webarchive|url=https://web.archive.org/web/20131207133417/http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf |date=2013-12-07 }}, ''Internet Research'' '''19'''(1)&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, group betweenness centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&lt;br /&gt;
&lt;br /&gt;
中心性的概念也扩展到了群体层次。例如，组间的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''显示了连接穿过组的成对非组成员的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Geodesics &amp;lt;/font&amp;gt;'''的比例。&lt;br /&gt;
&lt;br /&gt;
==See also==&lt;br /&gt;
==又及==&lt;br /&gt;
* [[Alpha centrality]]&lt;br /&gt;
&lt;br /&gt;
* [[Core–periphery structure]]&lt;br /&gt;
&lt;br /&gt;
* [[Distance (graph theory)|Distance in graphs]]&lt;br /&gt;
&lt;br /&gt;
*阿尔法中心性&lt;br /&gt;
&lt;br /&gt;
*核心—外围结构&lt;br /&gt;
&lt;br /&gt;
*距离（图理论）图中的距离&lt;br /&gt;
&lt;br /&gt;
==Notes and references==&lt;br /&gt;
&lt;br /&gt;
{{Reflist}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Further reading==&lt;br /&gt;
拓展阅读&lt;br /&gt;
* Koschützki, D.; Lehmann, K. A.; Peeters, L.; Richter, S.; Tenfelde-Podehl, D. and Zlotowski, O. (2005) Centrality Indices. In Brandes, U. and Erlebach, T. (Eds.)  ''Network Analysis: Methodological Foundations'', pp.&amp;amp;nbsp;16–61, LNCS 3418, Springer-Verlag.&lt;br /&gt;
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[[Category:Graph theory]]&lt;br /&gt;
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Category:Graph theory&lt;br /&gt;
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分类: 图论&lt;br /&gt;
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[[Category:Graph algorithms]]&lt;br /&gt;
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Category:Graph algorithms&lt;br /&gt;
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分类: 图形算法&lt;br /&gt;
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[[Category:Algebraic graph theory]]&lt;br /&gt;
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Category:Algebraic graph theory&lt;br /&gt;
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分类: 代数图论&lt;br /&gt;
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[[Category:Networks]]&lt;br /&gt;
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Category:Networks&lt;br /&gt;
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分类: 网络&lt;br /&gt;
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[[Category:Network analysis]]&lt;br /&gt;
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Category:Network analysis&lt;br /&gt;
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分类: 网络分析&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Centrality]]. Its edit history can be viewed at [[网络中心性/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
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		<title>网络中心性</title>
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		<updated>2020-12-05T03:13:46Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* 中心性指数的定义与特性Definition and characterization of centrality indices */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;此词条暂由水流心不竞初译，未经审校，带来阅读不便，请见谅。&lt;br /&gt;
&lt;br /&gt;
{{for|the statistical concept|Central tendency}}&lt;br /&gt;
{{Network Science}}&lt;br /&gt;
&lt;br /&gt;
In [[graph theory]] and [[network theory|network analysis]], indicators of '''centrality''' identify the most important [[vertex (graph theory)|vertices]] within a graph. Applications include identifying the most influential person(s) in a [[social network]], key infrastructure nodes in the [[Internet]] or [[urban network]]s, and [[super-spreader]]s of disease. Centrality concepts were first developed in [[social network analysis]], and many of the terms used to measure centrality reflect their [[sociology|sociological]] origin.&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
In graph theory and network analysis, indicators of centrality identify the most important vertices within a graph. Applications include identifying the most influential person(s) in a social network, key infrastructure nodes in the Internet or urban networks, and super-spreaders of disease. Centrality concepts were first developed in , and many of the terms used to measure centrality reflect their sociological origin.&lt;br /&gt;
&lt;br /&gt;
They should not be confused with [[node influence metric]]s, which seek to quantify the influence of every node in the network.&lt;br /&gt;
&lt;br /&gt;
They should not be confused with node influence metrics, which seek to quantify the influence of every node in the network.&lt;br /&gt;
&lt;br /&gt;
在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;图论 graph theory &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络分析 network analysis &amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性 centrality &amp;lt;/font&amp;gt;'''指标用于识别图中最重要的顶点。其应用包括在社会网络中识别出最有影响力的个人，在因特网或城市网络中识别出最为关键的基础设施节点，以及识别疾病的超级传播者。中心性的概念最初由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;社会网络分析 social network analysis&amp;lt;/font&amp;gt;'''所发展，因此许多用于衡量中心性的术语都反映出了它们的社会学出身。&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;中心性不应与节点影响度相混淆，后者意在量化网络中每个节点的影响。&lt;br /&gt;
&lt;br /&gt;
==中心性指数的定义与特性Definition and characterization of centrality indices==&lt;br /&gt;
&lt;br /&gt;
Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性指数 centrality indices&amp;lt;/font&amp;gt;'''是对“重要顶点的特征是什么”这一问题的回答，答案以图顶点的实值函数的方式给出，在这些顶点上的取值的排序标识出最重要的节点。&lt;br /&gt;
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The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
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The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
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“重要性”这个词有许多含义，导致了许多不同的中心性定义。分为两类。&lt;br /&gt;
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&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important.&amp;lt;ref name=Borgatti2005/&amp;gt; &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt; Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important. Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&lt;br /&gt;
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“重要性”可以被认为与一种跨网络的流动或传输有关。这允许根据它们认为重要的流类型对中心性进行分类。这两种方法都将中心性划分为不同的类别。进一步的推论是，适用于一个类别的中心性在（推广）应用于另一个类别时往往会“出错”。&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one ([[Centrality#Degree centrality|degree centrality]]) to infinite walks ([[Centrality#Eigenvector centrality|eigenvalue centrality]]).&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=&amp;quot;Benzi2013&amp;quot;&amp;gt;{{cite journal | last1=Benzi | first1=Michele | last2=Klymko| first2=Christine | year=2013 |title= A matrix analysis of different centrality measures |arxiv=1312.6722 | doi=10.1137/130950550 | volume=36 | issue=2 | journal=SIAM Journal on Matrix Analysis and Applications | pages=686–706}}&amp;lt;/ref&amp;gt; The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one (degree centrality) to infinite walks (eigenvalue centrality). The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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当中心性按照它们对'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 内聚性Cohesiveness&amp;lt;/font&amp;gt;'''的趋近程度来分类时，很明显，大多数中心性都集中在一个类别中。从一个给定顶点开始对步数计数，不同之处只在于行走的定义和计数方式。对该组描述的约束限制，从位置中心（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心度Degree centrality&amp;lt;/font&amp;gt;'''）到单元域（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征中心度Eigenvalue centrality&amp;lt;/font&amp;gt;'''），观察到许多中心性都有这种相似关系，这也许可以解释这些指数之间的高阶相关性。&lt;br /&gt;
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===Characterization by network flows==&lt;br /&gt;
==网络流特征==&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at once.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at oe.&lt;br /&gt;
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一个网络可以被看成是对某种物体流动的路径描述。使基于流的类型和由中心性编码的路径类型（同时）得到表征。一个流可以基于传输，每个不可分割的项目从一个节点到另一个节点，就像一个包裹从配送站送到客户的房子。第二种情况是串行复制，在这种情况下，一个项从源节点被复制到达目标节点。例如通过流言传播信息，以私有方式传播信息，并在流程结束时通知源节点和目标节点。最后一种情况是并行复制，即同时将项目复制到多个链接，就像无线电广播一次性向多个听众提供相同的信息。&lt;br /&gt;
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Likewise, the type of path can be constrained to [[Distance (graph theory)|geodesics]] (shortest paths), [[Glossary of graph theory terms#path|paths]]  (no vertex is visited more than once), [[Glossary of graph theory terms#trail|trails]] (vertices can be visited multiple times, no edge is traversed more than once), or [[Glossary of graph theory terms#walk|walks]] (vertices and edges can be visited/traversed multiple times).&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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Likewise, the type of path can be constrained to geodesics (shortest paths), paths  (no vertex is visited more than once), trails (vertices can be visited multiple times, no edge is traversed more than once), or walks (vertices and edges can be visited/traversed multiple times).&lt;br /&gt;
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同样，路径类型可以被限定为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Distance &amp;lt;/font&amp;gt;'''(最短路径)、路径(对顶点的访问不超过一次)、小径(可以访问多次顶点，没有边被访问超过一次)或者步子(可以访问/遍历多次顶点和边)。&lt;br /&gt;
===Characterization by walk structure===&lt;br /&gt;
==行走结构特征==&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either ''radial'' or ''medial.'' Radial centralities count walks which start/end from the given vertex. The [[Centrality#Degree centrality|degree]] and [[Centrality#Eigenvector centrality|eigenvalue]] centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's [[Centrality#Betweenness centrality|betweenness]] centrality, the number of shortest paths which pass through the given vertex.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either radial or medial. Radial centralities count walks which start/end from the given vertex. The degree and eigenvalue centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's betweenness centrality, the number of shortest paths which pass through the given vertex.&lt;br /&gt;
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可以从中心性的构造方式推导出另一种分类方法。这又分成了两个类。中心点可以是放射状的，也可以是内侧的。从给定顶点开始/结束的径向中心点数。度和特征值中心是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 径向中心Radial centralities&amp;lt;/font&amp;gt;'''的例子，计算长度为一或无穷大的行走的个数。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中间中心性Medial centralities&amp;lt;/font&amp;gt;'''计算通过给定顶点的步数。典型的例子是 弗里曼的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality,&amp;lt;/font&amp;gt;'''，即穿过给定顶点的最短路径的数量。&lt;br /&gt;
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Likewise, the counting can capture either the ''volume'' or the ''length'' of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's [[Centrality#Closeness centrality|closeness]] centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example.&amp;lt;ref name=Borgatti2006/&amp;gt; Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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Likewise, the counting can capture either the volume or the length of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's closeness centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example. Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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同样地，计数可以抓住行走的体积或长度。体积是给定类型的行走的总数。上一段的三个例子就属于这一类。长度则给出从给定顶点到图中其余顶点的距离。弗里曼 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，即从一个给定顶点到所有其他顶点的测地距离，是最著名的例子。请注意，这种分类独立于步行计数的类型(即：步行，小道，路径，测地线)。&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&lt;br /&gt;
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博尔加蒂和埃弗雷特提出，这种类型学为如何最好地比较中心性度量提出了建议。在这个22分类中，放在同一盒子中的中心点足够相似，可以做出合理的选择; 人们可以合理地比较哪个对于给定的应用更好。然而，不同盒子中的度量方法是截然不同的。只有在预先确定哪个类别更适用的情况下，对相对适应性的评估才会发生，这使得比较变得毫无意义。&lt;br /&gt;
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===Radial-volume centralities exist on a spectrum===&lt;br /&gt;
==光谱上存在的径向体积中心==&lt;br /&gt;
The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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步行结构的特征表明，几乎所有广泛使用的中心性都是径向体积的衡量。这得出结论顶点的中心性是与之相关联的顶点中心性的函数。中心性根据如何定义关联而不同。&lt;br /&gt;
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Bonacich showed that if association is defined in terms of [[Glossary of graph theory terms#walk|walks]], then a family of centralities can be defined based on the length of walk considered.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;/&amp;gt; [[Centrality#Degree centrality|Degree centrality]] counts walks of length one, while [[Centrality#Eigenvector centrality|eigenvalue centrality]] counts walks of length infinity. Alternative definitions of association are also reasonable. [[Alpha centrality]] allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich showed that if association is defined in terms of walks, then a family of centralities can be defined based on the length of walk considered. Degree centrality counts walks of length one, while eigenvalue centrality counts walks of length infinity. Alternative definitions of association are also reasonable. Alpha centrality allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich 指出，如果联想是根据行走来定义的，那么可以根据考虑的行走长度来定义一个中心性家族。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''计算长度为1的行走，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征值中心性Eigenvalue centrality  &amp;lt;/font&amp;gt;'''计算长度为无穷大的行走。关联的其他定义也是合理的。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 阿尔法中心性Alpha centrality&amp;lt;/font&amp;gt;'''允许顶点有一个外部影响源。埃斯特拉达的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图中心性Subgraph centrality &amp;lt;/font&amp;gt;'''提出只计算封闭路径(三角形、正方形等)。).&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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这些测量方法的核心是这种现象：图中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵&amp;lt;/font&amp;gt;'''的幂给出了由该幂给出的散步长度的数目。同样，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 矩阵指数Matrix exponential&amp;lt;/font&amp;gt;'''也与给定长度的行走次数密切相关。邻接矩阵的初始转换允许对步行计数的类型进行不同的定义。无论采用哪种方法，顶点的中心性都可以表示为无穷和&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum _ { k = 0} ^ infty a _ { r } ^ { k } beta ^ k &amp;lt;/math &amp;gt; &lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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矩阵能量或者&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum { k = 0} ^ infty frac {(a _ r beta) ^ k }{ k！{/math &amp;gt; &lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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对于矩阵指数函数，其中&lt;br /&gt;
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* &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; is walk length,&lt;br /&gt;
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* &amp;lt;math&amp;gt;A_R&amp;lt;/math&amp;gt; is the transformed adjacency matrix, and&lt;br /&gt;
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* &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; is a discount parameter which ensures convergence of the sum.&lt;br /&gt;
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K为步长，A_R是邻接矩阵的转秩，贝达是保证收敛的折扣参数。&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. [[Alpha centrality]] replaces the adjacency matrix with its [[resolvent formalism|resolvent]]. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to [[Centrality#Degree centrality|degree centrality]]. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to [[Centrality#Eigenvector centrality|eigenvalue centrality]].&amp;lt;ref name=Benzi2013/&amp;gt;&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. Alpha centrality replaces the adjacency matrix with its resolvent. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to degree centrality. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to eigenvalue centrality.&lt;br /&gt;
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博纳奇的一系列措施并没有改变邻接矩阵。阿尔法集中性用它的解决方案替代了邻接矩阵。子图集中性用它的踪迹取代了邻接矩阵。一个令人吃惊的结论是，不管邻接矩阵最初的转变是什么，所有这些方法都有共同的限制行为。随着贝塔系数趋近于零，指数收敛到度中心性。随着贝塔系数接近其最大值，指数收敛到特征值的中心性。&lt;br /&gt;
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===Game-theoretic centrality===&lt;br /&gt;
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=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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上述大多数标准措施的共同特点是，它们通过只关注一个节点本身所扮演的角色来评估确定节点的重要性。然而, 在许多应用中，这种方法是不充分的，因为可能会发生协同作用&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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如果将节点的功能分组考虑。&lt;br /&gt;
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[[File:Game-theoretic centrality.png|Example of game-theoretic centrality]]&lt;br /&gt;
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Example of game-theoretic centrality&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''的例子&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in &amp;lt;ref&amp;gt;Michalak, Aadithya, Szczepański, Ravindran, &amp;amp; Jennings {{ArXiv|1402.0567}}&amp;lt;/ref&amp;gt; uses the [[Shapley value]]. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in  uses the Shapley value. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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例如，考虑阻止流行病的问题。看看上面的网络图像，我们应该给哪些节点接种疫苗？基于前面描述的措施，我们希望识别在疾病传播中最重要的节点。仅仅基于中心的方法，即关注节点的个别特性，可能不是一个好主意。红色方块中的节点，单独不能阻止疾病的传播，但把它们作为一个群体来考虑，我们清楚地看到，如果疾病在节点 &amp;lt; math &amp;gt; v _ 1 &amp;lt;/math &amp;gt; 、 &amp;lt; math &amp;gt; v _ 4 &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; v _ 5 &amp;lt;/math &amp;gt; 中开始，它们就能阻止疾病的传播。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''试图利用博弈论中的工具来研究所描述的问题和机会。本文提出的方法使用了 Shapley 值。由于 Shapley 值计算的时间复杂性，这一领域的大部分工作都集中在实现新的算法和方法，这些算法和方法依赖于网络的特殊拓扑结构或问题的特殊性质。这种方法可以将时间复杂度从指数级降低到多项式级。&lt;br /&gt;
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Similarly, the solution concept [[authority distribution]] (&amp;lt;ref&amp;gt;{{cite journal |last=Hu |first=Xingwei |first2=Lloyd |last2=Shapley |title=On Authority Distributions in Organizations |journal=Games and Economic Behavior |volume=45 |pages=132–170 |year=2003 | doi = 10.1016/s0899-8256(03)00130-1 }}&amp;lt;/ref&amp;gt;) applies the [[Shapley-Shubik power index]], rather than the [[Shapley value]], to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020)&amp;lt;ref&amp;gt;{{cite journal|last=Hu|first=Xingwei|year=2020|volume=7|title=Sorting big data by revealed preference with application to college ranking |journal=Journal of Big Data|doi=10.1186/s40537-020-00300-1|doi-access=free}}&amp;lt;/ref&amp;gt;, such as ranking U.S. colleges.&lt;br /&gt;
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Similarly, the solution concept authority distribution () applies the Shapley-Shubik power index, rather than the Shapley value, to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020), such as ranking U.S. colleges.&lt;br /&gt;
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同样，'''&amp;lt;font color=&amp;quot;#CD32CD&amp;quot;&amp;gt; 加权分布概念的解()The solution concept authority distribution () &amp;lt;/font&amp;gt;'''采用 Shapley-Shubik 幂指数，而不是 Shapley 值来衡量双方之间的直接影响。这种分布确实是一种产生'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征向量中心性Engenvector centrality&amp;lt;/font&amp;gt;'''的类型。它用于对 Hu (2020)中的大数据对象进行排序，比如美国大学排名。&lt;br /&gt;
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== Important limitations ==&lt;br /&gt;
==重要限制==&lt;br /&gt;
Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the [[Krackhardt kite graph]], for which three different notions of centrality give three different choices of the most central vertex.&amp;lt;ref&amp;gt;{{cite journal|title=Assessing the Political Landscape: Structure, Cognition, and Power in Organizations|first=David|last=Krackhardt|authorlink=David Krackhardt|journal=Administrative Science Quarterly|volume=35|issue=2|date=June 1990|pages=342–369|doi=10.2307/2393394|jstor=2393394}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the Krackhardt kite graph, for which three different notions of centrality give three different choices of the most central vertex.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中心性Centrality&amp;lt;/font&amp;gt;'''指标有两个重要的局限性，一个显而易见，另一个则不易察觉。显而易见的局限性是，对于一个应用最优的中心性对于另一个应用常常是次优的。事实上，如果不是这样，我们就不需要这么多不同的中心性。克拉克哈特风筝图为这一现象提供了一个例证，对于这个图，三个不同的中心性概念给出了三个最中心顶点的不同选择。&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices.&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=Borgatti2005/&amp;gt; This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  [[node influence metric]]s to address this problem.&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices. This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  node influence metrics to address this problem.&lt;br /&gt;
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更不易察觉的限制是通常会错误地认为顶点中心性表示顶点的相对重要性。中心性指数被明确地设计来产生一个指出最重要顶点的排名。在刚才提到的限制下，他们做得很好。它们通常不用来测量节点的影响力。最近，网络物理学家开始开发'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;节点影响度量Node influence metrics &amp;lt;/font&amp;gt;'''来解决这个问题。&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying [[Centrality#Freeman centralization|Freeman centralization]] to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt; This approach, however, is seldom seen in practice.{{citation needed|reason=I've come across quite some theoretical studies that indicate otherwise. My suggestion is to remove this sentence, if reasonable citation is not provided.|date=September 2015}}&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying Freeman centralization to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores. This approach, however, is seldom seen in practice.&lt;br /&gt;
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错误有两方面。首先，一个排名只根据顶点的重要性排序，它并不对节点重要性的不同水平进行量化区分。这可以通过将 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;'''应用到中心性度量来缓解，这种度量可以根据节点的不同中心性得分来判断节点的重要性。此外， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;''使人们能够通过比较几个网络的最高中心性得分来比较它们。然而，这种方法在实践中很少见到。&lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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其次，用以(正确地)识别给定网络/应用中最重要顶点的特征并不一定可推广到其余顶点。&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot; /&amp;gt;&amp;lt;ref name=&amp;quot;daSilva2012&amp;quot;&amp;gt;{{cite journal | last1=da Silva|first1=Renato |last2=Viana|first2=Matheus|last3=da F. Costa |first3=Luciano| title=Predicting epidemic outbreak from individual features of the spreaders| journal=J. Stat. Mech.: Theory Exp. | year=2012|volume=2012|pages=P07005|number=7 | doi=10.1088/1742-5468/2012/07/p07005|arxiv=1202.0024|bibcode=2012JSMTE..07..005A}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Bauer2012&amp;quot;&amp;gt;{{cite journal | last1=Bauer|first1=Frank | last2=Lizier|first2=Joseph|title=Identifying influential spreaders and efficiently estimating infection numbers in epidemic models: A walk counting approach| journal=Europhys Lett | year=2012| volume=99| pages=68007|number=6 | doi=10.1209/0295-5075/99/68007|arxiv=1203.0502|bibcode=2012EL.....9968007B}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Sikic2013&amp;quot;&amp;gt;{{ cite journal| last1= Sikic| first1=Mile|last2=Lancic|first2=Alen|last3=Antulov-Fantulin|first3=Nino|last4=Stefanic|first4=Hrvoje| title = Epidemic centrality -- is there an underestimated epidemic impact of network peripheral nodes? |journal = The European Physical Journal B |volume=86 |number=10 |pages=1–13 |year=2013 | doi=10.1140/epjb/e2013-31025-5|arxiv=1110.2558 | bibcode=2013EPJB...86..440S}}&amp;lt;/ref&amp;gt; This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&amp;lt;ref name=&amp;quot;Ghoshal2011&amp;quot;&amp;gt;{{cite journal | last1=Ghoshal | first1= G. | last2= Barabsi |first2= A L | title = Ranking stability and super-stable nodes in complex networks. | journal = Nat Commun | volume =2 | page = 394| year= 2011 | doi=10.1038/ncomms1396 | pmid= 21772265 | bibcode=2011NatCo...2..394G | doi-access= free }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless. This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&lt;br /&gt;
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对于大多数其他网络节点，排名可能是没有意义的。这就解释了为什么，例如，只有谷歌图片搜索的前几个结果以合理的顺序出现。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页排名Pagerank&amp;lt;/font&amp;gt;'''是一个非常不稳定的度量，显示了在跳转参数小的调整之后频繁的秩逆转。&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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虽然中心性指数未能推广到网络的其他部分，乍看起来似乎是违反直觉的，但它直接遵循上述定义。&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot;&amp;gt;{{cite journal |last1= Lawyer |first1= Glenn |year= 2015 |title= Understanding the spreading power of all nodes in a network: a continuous-time perspective |journal=Sci Rep |volume=5|pages=8665|doi=10.1038/srep08665 |pmid=25727453 |pmc=4345333|arxiv=1405.6707|bibcode=2015NatSR...5E8665L}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&lt;br /&gt;
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复杂网络具有异构的拓扑结构。由于最佳度量取决于最重要顶点的网络结构，对于这些顶点最优的度量对于网络的其余部分是次优的。&lt;br /&gt;
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==Degree centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Degree (graph theory)}} &lt;br /&gt;
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[[File:6 centrality measures.png|thumb|right|300px|Examples of A) [[Betweenness centrality]], B) [[Closeness centrality]], C) [[Eigenvector centrality]], D) [[Degree centrality]], E) [[Centrality#Harmonic centrality|Harmonic centrality]] and F) [[Katz centrality]] of the same graph.]]&lt;br /&gt;
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Examples of A) [[Betweenness centrality, B) Closeness centrality, C) Eigenvector centrality, D) Degree centrality, E) Harmonic centrality and F) Katz centrality of the same graph.]]&lt;br /&gt;
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实例 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; a)[中介中心性A) [[Betweenness centrality,b)紧密中心性，B) Closeness centrality, c)特征向量中心性，C) Eigenvector centrality, d)度中心性，D) Degree centrality, e)调和中心性，E) Harmonic centrality andf) 卡兹Katz 中心性]F) Katz centrality .]]&amp;lt;/font&amp;gt;'''&lt;br /&gt;
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Historically first and conceptually simplest is '''degree centrality''', which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely [[indegree]] and [[outdegree]]. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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Historically first and conceptually simplest is degree centrality, which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely indegree and outdegree. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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历史上最简单的概念是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''，它定义为一个节点上发生的链接数量(即一个节点拥有的关系数量)。度可以根据节点捕获流经网络的任何东西(例如病毒或某些信息)的直接风险来解释。在有向网络的情况下(其中联系有方向) ，我们通常定义两个独立的度量，即 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度 Outdegree&amp;lt;/font&amp;gt;'''。因此，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度indegree&amp;lt;/font&amp;gt;'''是指向该节点的关系数，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度outdegree&amp;lt;/font&amp;gt;'''是指该节点指向其他节点的关系数。当关系与一些积极的方面如友谊或合作有关时， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''通常被解释为一种形式的受欢迎，而 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度Indegree&amp;lt;/font&amp;gt;'''则被解释为合群。&lt;br /&gt;
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The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
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The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
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对于给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边，度的中心性定义为&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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Calculating degree centrality for all the nodes in a graph takes [[big theta|&amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt;]] in a [[dense matrix|dense]] [[adjacency matrix]] representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a [[sparse matrix]] representation.&lt;br /&gt;
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Calculating degree centrality for all the nodes in a graph takes &amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt; in a dense adjacency matrix representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a sparse matrix representation.&lt;br /&gt;
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计算一个图中所有节点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''需要在图的稠密'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵Adjacency matrix &amp;lt;/font&amp;gt;'''表示中使用 Theta (v ^ 2) &amp;lt;/math &amp;gt; ，而在稀疏矩阵表示中使用 Theta (e) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of ''graph centralization''.&amp;lt;ref&amp;gt;Freeman, Linton C. &amp;quot;Centrality in social networks conceptual clarification.&amp;quot; Social networks 1.3 (1979): 215–239.&amp;lt;/ref&amp;gt; Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
&lt;br /&gt;
The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of graph centralization. Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
&lt;br /&gt;
节点级中心性的定义可以扩展到整个图，在这种情况下，我们指的是图的集中性。设 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 为 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''最高的节点。让 &amp;lt; math &amp;gt; x: = (y，z) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; | y | &amp;lt;/math &amp;gt; 节点连接图，最大化下列数量(&amp;lt; math &amp;gt; y * &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 中度最高的节点) :&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h = sum ^ { | y | }{ j = 1}[ c _ d (y *)-c _ d (y _ j)] &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
&lt;br /&gt;
Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
&lt;br /&gt;
相应地，图形 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''如下:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ h } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a [[star graph]]), and in this case&lt;br /&gt;
&lt;br /&gt;
The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a star graph), and in this case&lt;br /&gt;
&lt;br /&gt;
当图形 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 包含一个所有其他节点都连接的中心节点(一个星形图)时，&amp;lt; math &amp;gt; h &amp;lt;/math &amp;gt; 的值最大化，在这种情况下&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
(n-1)-1) = n ^ 2-3n + 2&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
所以，对于任意的图 &amp;lt; math &amp;gt; g: = (v，e) ，&amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ | v | ^ 2-3 | v | + 2} &amp;lt;/math &amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Closeness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Closeness centrality}}In a [[Connected component (graph theory)|connected]] [[Graph (discrete mathematics)|graph]], the [[Normalization (statistics)|normalized]] '''closeness centrality''' (or '''closeness''') of a node is the average length of the [[Shortest path problem|shortest path]] between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
&lt;br /&gt;
In a connected graph, the normalized closeness centrality (or closeness) of a node is the average length of the shortest path between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
&lt;br /&gt;
在连通图中，节点的标准'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''(或贴近性)是节点与图中所有其他节点之间最短路径的平均长度。因此，一个节点越是中心，它就越接近所有其他节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Closeness was defined by [[Alex Bavelas]] (1950) as the [[Multiplicative inverse|reciprocal]] of the '''farness''',&amp;lt;ref&amp;gt;Alex Bavelas. Communication patterns in task-oriented groups. ''J. Acoust. Soc. Am'', '''22'''(6):725–730, 1950.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;{{cite journal|year=1966|title=The centrality index of a graph|url=|journal=Psychometrika|volume=31|issue=4|pages=581–603|doi=10.1007/bf02289527|pmid=5232444|hdl=10338.dmlcz/101401|last1=Sabidussi|first1=G|hdl-access=free}}&amp;lt;/ref&amp;gt; that is:&lt;br /&gt;
&lt;br /&gt;
Closeness was defined by Alex Bavelas (1950) as the reciprocal of the farness, that is:&lt;br /&gt;
&lt;br /&gt;
亚历克斯 · 巴维拉斯(1950)将亲密度定义为相对于距离的倒数，即:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
C (x) = frac {1}{ sum _ y d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the [[Distance (graph theory)|distance]] between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the distance between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; d (y，x) &amp;lt;/math &amp;gt; 是顶点 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; 之间的距离。然而，当谈到'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''时，人们通常会提到它的标准化形式，一般是以前的公式乘以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; ，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。这种调整允许比较不同大小图形的节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Taking distances ''from'' or ''to'' all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in [[directed graph]]s (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
&lt;br /&gt;
Taking distances from or to all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in directed graphs (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
&lt;br /&gt;
从所有其他节点或到所有其他节点的距离在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 无向图Undirected graphs&amp;lt;/font&amp;gt;'''中是不相关的，但是在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 有向图Directed graphs&amp;lt;/font&amp;gt;'''中可能产生完全不同的结果(例如:一个网站可以从传出链接获得高的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，而从传入链接获得低的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''）。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
===Harmonic centrality===&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the '''harmonic centrality''' reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the harmonic centrality reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
在一个(不一定是连通的)图中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''反转了'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''定义中的和互反运算:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h (x) = sum { y neq x } frac {1}{ d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; 1/d (y，x) = 0 &amp;lt;/math &amp;gt; if there is no path from &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; to &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 。调和中心性可以通过除以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; 来标准化，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Harmonic centrality was proposed by [[Massimo Marchiori|Marchiori]] and [[Vito Latora|Latora]] (2000)&amp;lt;ref name=&amp;quot;marchiorilatora2000&amp;quot;&amp;gt;{{citation| journal = Physica A: Statistical Mechanics and Its Applications  | last1 = Marchiori | first1 = Massimo | last2 = Latora | first2 = Vito | year = 2000 | volume = 285 | issue = 3–4 | pages = 539–546 | title = Harmony in the small-world | doi=10.1016/s0378-4371(00)00311-3| arxiv = cond-mat/0008357 | bibcode = 2000PhyA..285..539M }}&amp;lt;/ref&amp;gt; and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot;&amp;lt;ref&amp;gt;{{cite journal|first1=Anthony|last1=Dekker|title=Conceptual Distance in Social Network Analysis|journal=Journal of Social Structure|volume=6|issue=3|year=2005|url=http://www.cmu.edu/joss/content/articles/volume6/dekker/index.html}}&amp;lt;/ref&amp;gt; and by Rochat (2009).&amp;lt;ref&amp;gt;{{cite conference  | author = Yannick Rochat  | title = Closeness centrality extended to unconnected graphs: The harmonic centrality index | conference = Applications of Social Network Analysis, ASNA 2009 | url = http://infoscience.epfl.ch/record/200525/files/%5bEN%5dASNA09.pdf }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Harmonic centrality was proposed by Marchiori and Latora (2000) and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot; and by Rochat (2009).&lt;br /&gt;
&lt;br /&gt;
调和中心性是由 Marchiori 和 Latora (2000)提出的，然后是 Dekker (2005)独立提出的，使用的名称是“有价值的中心性” ，Rochat (2009)。&lt;br /&gt;
&lt;br /&gt;
==Betweenness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Betweenness centrality}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Graph betweenness.svg|240px|right|thumb|Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.]]&lt;br /&gt;
&lt;br /&gt;
Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.&lt;br /&gt;
&lt;br /&gt;
色调(从红色 = 0到蓝色 = max)表示节点之间的距离。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
'''Betweenness''' is a centrality measure of a [[vertex (graph theory)|vertex]] within a [[Graph (discrete mathematics)|graph]] (there is also [[edge (graph theory)|edge]] betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by [[Linton Freeman]]&amp;lt;ref name=&amp;quot;freeman1977&amp;quot;&amp;gt;{{cite journal |last1 = Freeman |first1 = Linton | year=1977| title = A set of measures of centrality based upon betweenness | journal = Sociometry| volume=40|issue = 1 | pages=35–41 | doi=10.2307/3033543|jstor = 3033543 }}&amp;lt;/ref&amp;gt; In his conception, vertices that have a high probability to occur on a randomly chosen [[shortest path problem|shortest path]] between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
&lt;br /&gt;
Betweenness is a centrality measure of a vertex within a graph (there is also edge betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by Linton Freeman In his conception, vertices that have a high probability to occur on a randomly chosen shortest path between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
&lt;br /&gt;
中介性是图中顶点的中心性度量(也有边中介性，这里没有讨论)。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''量化了一个节点沿着其他两个节点之间的最短路径充当桥梁的次数。在林顿 · 弗里曼的概念中，在两个随机选择的顶点之间随机选择的最短路径上出现概率高的顶点具有很高的中介性。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
&lt;br /&gt;
The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
&lt;br /&gt;
在一个图 &amp;lt; math &amp;gt; g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的顶点之间的距离计算如下:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
# For each pair of vertices (''s'',''t''), compute the [[Shortest path problem|shortest paths]] between them.&lt;br /&gt;
&lt;br /&gt;
 For each pair of vertices (s,t), compute the shortest paths between them.&lt;br /&gt;
&lt;br /&gt;
对于每一对顶点(s，t) ，计算它们之间的最短路径。&lt;br /&gt;
&lt;br /&gt;
# For each pair of vertices (''s'',''t''), determine the fraction of shortest paths that pass through the vertex in question (here, vertex ''v'').&lt;br /&gt;
&lt;br /&gt;
 For each pair of vertices (s,t), determine the fraction of shortest paths that pass through the vertex in question (here, vertex v).&lt;br /&gt;
&lt;br /&gt;
对于每对顶点(s，t) ，确定通过该顶点(这里是顶点 v)的最短路径的分数。&lt;br /&gt;
&lt;br /&gt;
# Sum this fraction over all pairs of vertices (''s'',''t'').&lt;br /&gt;
&lt;br /&gt;
 Sum this fraction over all pairs of vertices (s,t).&lt;br /&gt;
&lt;br /&gt;
对所有顶点对(s，t)求这个分数的和。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
More compactly the betweenness can be represented as:&amp;lt;ref name=&amp;quot;brandes&amp;quot;&amp;gt;{{cite journal |last1 = Brandes |first1 = Ulrik | year=2001 |title = A faster algorithm for betweenness centrality  | journal = Journal of Mathematical Sociology| volume=25|issue = 2 | pages=163–177| url = http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.11.2024 | accessdate = October 11, 2011| format = PDF | doi=10.1080/0022250x.2001.9990249|citeseerx = 10.1.1.11.2024 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
More compactly the betweenness can be represented as:&lt;br /&gt;
&lt;br /&gt;
更确切地说，两者之间的关系可以表示为:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
{ math &amp;gt; c _ b (v) = sum _ { s neq v neq t in v } frac { sigma _ st }(v)}{ sigma _ st } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including ''v'', which for [[Digraph (mathematics)|directed graphs]] is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected [[Star (graph theory)|star graph]], the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including v, which for directed graphs is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected star graph, the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; sigma { st } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { st }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径数。有向图是 &amp;lt; math &amp;gt; (n-1)(n-2) &amp;lt;/math &amp;gt; ，无向图是 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; 。例如，在一个无向星图中，中心顶点(包含在每个可能的最短路径中)的中介性为 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; (1，如果标准化) ，而叶子(包含在没有最短路径中)的中介性为0。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires [[Big O notation|&amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt;]] time with the [[Floyd–Warshall algorithm]]. However, on sparse graphs, [[Johnson's algorithm]] may be more efficient, taking [[Big O notation|&amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt;]] time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm&amp;lt;ref name=brandes/&amp;gt; which takes [[Big O notation|&amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt;]] time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&amp;lt;ref name=&amp;quot;brandes&amp;quot; /&amp;gt;&lt;br /&gt;
&lt;br /&gt;
From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires &amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt; time with the Floyd–Warshall algorithm. However, on sparse graphs, Johnson's algorithm may be more efficient, taking &amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt; time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm which takes &amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt; time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&lt;br /&gt;
&lt;br /&gt;
从计算的角度来看，图中所有顶点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介和紧密中心性Betweenness and Closeness centralities&amp;lt;/font&amp;gt;'''都涉及到计算图中所有顶点对之间的最短路径，这就需要用 Floyd-Warshall 算法计算时间。然而，对于稀疏图，约翰逊算法的效率可能更高，采用 &amp;lt; math &amp;gt; o (v ^ 2 log v + v e) &amp;lt;/math &amp;gt; 时间。在不加权图的情况下，可以用 Brandes 的算法进行计算，该算法需要 &amp;lt; math &amp;gt; o (v e) &amp;lt;/math &amp;gt; 时间。一般情况下，这些算法假定图是无向的，并且连通图中允许有圈和多条边。当专门处理网络图时，图通常没有环或多条边来维持简单的关系(其中的边表示两个人或顶点之间的联系)。在这种情况下，使用 Brandes 的算法将最终的中心性分数除以2来计算每条被重复计算的最短路径。&lt;br /&gt;
&lt;br /&gt;
==Eigenvector centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Eigenvector centrality}}&lt;br /&gt;
&lt;br /&gt;
'''Eigenvector centrality''' (also called '''eigencentrality''') is a measure of the influence of a [[node (networking)|node]] in a [[network (mathematics)|network]]. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&amp;lt;ref&amp;gt;{{cite journal|title = The mathematics of networks|url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf|author = M. E. J. Newman|accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;/&amp;gt; [[Google]]'s [[PageRank]] and the [[Katz centrality]] are variants of the eigenvector centrality.&amp;lt;ref name=&amp;quot;ams&amp;quot;&amp;gt;{{Cite web | url=http://www.ams.org/samplings/feature-column/fcarc-pagerank | title=American Mathematical Society}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Eigenvector centrality (also called eigencentrality) is a measure of the influence of a node in a network. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''(也称为特征中心性)是衡量网络中节点影响的一个指标。它将相对得分分配给网络中的所有节点，这是基于这样一个概念: 与得分较高的节点相比，与得分较低的节点相同的连接对所涉及的节点的得分贡献更大。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=== Using the adjacency matrix to find eigenvector centrality ==&lt;br /&gt;
==使用'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''发现'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the [[adjacency matrix]], i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
&lt;br /&gt;
For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the adjacency matrix, i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
&lt;br /&gt;
对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 让 &amp;lt; math &amp;gt; a = (a { v，t }) &amp;lt;/math &amp;gt; 成为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''，即。如果顶点 &amp;lt; math &amp;gt; &amp;gt; v &amp;lt;/math &amp;gt; 与 math &amp;gt; t &amp;lt;/math &amp;gt; 相连，而 &amp;lt; math &amp;gt; a { v，t } = 0 &amp;lt;/math &amp;gt; 否则。顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分可以定义为:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
在 m (v)} x _ t = frac {1}{ lambda } sum { t in g } a { v，t } x _ t &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the [[eigenvector]] equation&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the eigenvector equation&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; m (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 和 &amp;lt; math &amp;gt; &amp;gt; lambda &amp;lt;/math &amp;gt; 的邻居集合。通过一个小的重新排列，这可以被重写成向量符号，作为特征向量方程&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[ math &amp;gt; mathbf { Ax } = { lambda } mathbf { x } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
In general, there will be many different [[eigenvalue]]s &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the [[Perron–Frobenius theorem]]. This greatest eigenvalue results in the desired centrality measure.&amp;lt;ref&amp;gt;{{cite journal  | author = M. E. J. Newman  | title = The mathematics of networks  | url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf  | accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt; The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices ''n''. [[Power iteration]] is one of many [[eigenvalue algorithm]]s that may be used to find this dominant eigenvector.&amp;lt;ref name=&amp;quot;ams&amp;quot; /&amp;gt; Furthermore, this can be generalized so that the entries in ''A'' can be real numbers representing connection strengths, as in a [[stochastic matrix]].&lt;br /&gt;
&lt;br /&gt;
In general, there will be many different eigenvalues &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the Perron–Frobenius theorem. This greatest eigenvalue results in the desired centrality measure. The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices n. Power iteration is one of many eigenvalue algorithms that may be used to find this dominant eigenvector. Furthermore, this can be generalized so that the entries in A can be real numbers representing connection strengths, as in a stochastic matrix.&lt;br /&gt;
&lt;br /&gt;
一般情况下，存在许多不同的特征值，对于这些特征值存在一个非零特征向量解。由于邻接矩阵中的条目是非负的，所以由 Perron-弗罗贝尼乌斯定理得出，它有一个实的和正的唯一最大特征值。由这个最大的特征值得出期望的中心性度量。相关特征向量的 &amp;lt; math &amp;gt; v ^ { th } &amp;lt;/math &amp;gt; 分量给出了网络中顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分。特征向量只定义了一个公共因子，所以只有顶点中心的比例是明确定义的。要定义一个绝对分数，必须对特征向量进行标准化，例如，使所有顶点的和为1或顶点的总数n。此外，这可以通用，使得 a 中的条目可以是表示连接强度的真实数字，就像'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 随机矩阵Stochastic matrix&amp;lt;/font&amp;gt;'''中一样。&lt;br /&gt;
&lt;br /&gt;
==Katz centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Katz centrality}}&lt;br /&gt;
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'''Katz centrality'''&amp;lt;ref&amp;gt;Katz, L. 1953. A New Status Index Derived from Sociometric Index. Psychometrika, 39–43.&amp;lt;/ref&amp;gt; is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
Katz centrality is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''是度中心性的推广。度中心性度量的是直接邻居的数量，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''度量的是通过一条路径可以连接的所有节点的数量，而远处节点的贡献会受到'''&amp;lt;font color=&amp;quot;#32CD32&amp;quot;&amp;gt; '削弱（惩罚？）Penalized&amp;lt;/font&amp;gt;''。在数学上，它被定义为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[数学][数学]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; (0,1) &amp;lt;/math &amp;gt; 中的衰减因子。&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
&lt;br /&gt;
Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''可以看作是特征向量中心性的变体。Katz 中心性的另一种形式是&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
(x _ j + 1) &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
与特征向量中心性的表达式相比，&amp;lt; math &amp;gt; x _ j &amp;lt;/math &amp;gt; 被 &amp;lt; math &amp;gt; x _ j + 1所代替&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
It is shown that&amp;lt;ref&amp;gt;{{cite journal | last1 = Bonacich | first1 = P | year = 1991 | title = Simultaneous group and individual centralities | url = | journal = Social Networks | volume = 13 | issue = 2| pages = 155–168 | doi=10.1016/0378-8733(91)90018-o}}&amp;lt;/ref&amp;gt; the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
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It is shown that the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
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结果表明，主特征向量(与 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; ，邻接矩阵的最大特征值相关)是 Katz 中心性的极限，因为 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 接近 &amp;lt; math &amp;gt; tfrac {1}{ lambda } &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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== PageRank centrality ==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页分布中心性PageRank&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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{{main|PageRank}}'''[[PageRank]]''' satisfies the following equation&lt;br /&gt;
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PageRank satisfies the following equation&lt;br /&gt;
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PageRank满足下面的等式&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
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1-alpha { n } ，&amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
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其中&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[ math &amp;gt; l (j) = sum { i } a { ji } &amp;lt;/math &amp;gt; &lt;br /&gt;
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&lt;br /&gt;
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is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&amp;lt;ref&amp;gt;[http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf How does Google rank webpages?] {{webarchive | url= https://web.archive.org/web/20120131083328/http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf |date=January 31, 2012 }} 20Q: About Networked Life&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&lt;br /&gt;
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是节点 &amp;lt; math &amp;gt; j &amp;lt;/math &amp;gt; (或有向图中出站链接的数量)的邻居数量。与特征向量中心性和 Katz 中心性相比，尺度因子 &amp;lt; math &amp;gt; l (j) &amp;lt;/math &amp;gt; 是一个主要的区别。PageRank 和特征向量中心性的另一个区别是 PageRank 向量是一个左手特征向量(注意因子 &amp;lt; math &amp;gt; a _ { ji } &amp;lt;/math &amp;gt; 具有相反的索引)。&lt;br /&gt;
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==Percolation centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&amp;lt;ref name=&amp;quot;piraveenan2013&amp;quot;&amp;gt;{{cite journal |last1 = Piraveenan |first1 = M. |last2 = Prokopenko |first2 = M.|last3 = Hossain|first3 = L. |year=2013| title = Percolation Centrality: Quantifying Graph-Theoretic Impact of Nodes during Percolation in Networks | journal = PLOS One | volume=8 | issue=1 | doi=10.1371/journal.pone.0053095 | pages=e53095 | pmid=23349699 | pmc=3551907| bibcode=2013PLoSO...853095P }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&lt;br /&gt;
&lt;br /&gt;
在复杂网络中，存在大量的中心性度量来确定单个节点的“重要性”。然而，这些度量单纯从拓扑学的角度来量化节点的重要性，节点的值并不以任何方式依赖于节点的状态。不管网络动态如何，它都保持不变。即使对于加权的两者之间的度量也是如此。然而，一个节点可能很好地位于'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''或其他中心性度量的中心位置，但可能不是位于有过滤的网络的上下文中的中心位置。在许多情况下，复杂网络中都会出现“传染”现象。例如，病毒或细菌感染可以通过人们的社交网络传播，也就是所谓的接触网络。还可以在更高的抽象层次上考虑疾病的传播问题，设想通过公路、铁路或空中连接起来的城镇或人口中心网络。计算机病毒可以通过计算机网络传播。关于商业活动和交易的谣言或新闻也可以通过人们的社交网络传播。在所有这些情况下，一种“传染病”在一个复杂网络的链接上传播，随着它的传播，无论是可恢复的还是不可恢复的，都会改变节点的“状态”。例如，在流行病学方案中，随着感染扩散，个人从”易感”状态转变为”受感染”状态。在上面的例子中，随着传染的扩散，每个节点可以采取的状态可以是二进制的(例如接收/没有接收到一条新闻)、离散的(易感/受感染/康复) ，甚至是连续的(例如一个城镇中受感染的人的比例) 。这些情景的共同特点是，传染的扩散导致网络中节点状态的改变。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''（PC)就是基于这个思想而提出的，它特别地衡量了节点在协助网络渗滤方面的重要性。这项措施是由 piraveanan 等人提出的。&lt;br /&gt;
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'''Percolation centrality''' is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
&lt;br /&gt;
Percolation centrality is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''定义为在给定时间内一个给定节点的过滤路径的比例。“渗滤路径”是一对节点之间的最短路径，其中源节点被渗滤(例如，被感染)。目标节点可以是过滤的或非过滤的，或处于部分过滤状态。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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:&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; PC ^ t (v) = frac {1}{ N-2} sum { s neq v neq r } frac { sigma { sr }(v)}{ sigma { sr }} frac { x ^ t }{ sum {[{ x ^ t } i }}}]}}-{ x ^ t }{ v } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; σ { sr } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; r &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { sr }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径的总数。在时间 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 时，节点的过滤状态用 &amp;lt; math &amp;gt; { x ^ t } _ i &amp;lt;/math &amp;gt; 表示，两个特殊情况是当 &amp;lt; math &amp;gt; { x ^ t } _ i = 0 &amp;lt;/math &amp;gt; 表示在时间上是非过滤状态，而当 &amp;lt; math &amp;gt; &amp;lt; x ^ t &amp;lt;/math &amp;gt; i = 1 &amp;lt;/math &amp;gt; 表示在时间上是完全过滤状态。两者之间的值表示部分过滤状态(例如，在一个城镇网络中，这是该城镇感染者的百分比)。&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in [[Big O notation|&amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt;]] time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is [[Big O notation|&amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;]].&lt;br /&gt;
&lt;br /&gt;
The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in &amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt; time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is &amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
渗流路径的权重取决于分配给源节点的渗流水平，前提是源节点的渗流水平越高，源节点的路径就越重要。因此，位于源自高渗滤节点的最短路径上的节点可能对渗滤更为重要。PC 的定义也可以扩展到包括目标节点的权重。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''计算运行在 &amp;lt; math &amp;gt; o (NM) &amp;lt;/math &amp;gt; 时间，采用了 Brandes 快速算法的有效实现，如果计算需要考虑目标节点的权重，最坏情况下时间为 &amp;lt; math &amp;gt; o (n ^ 3) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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==Cross-clique centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 交叉团中心性Cross-clique centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
'''Cross-clique centrality''' of a single node in a complex graph determines the connectivity of a node to different [[clique (graph theory)|clique]]s. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in &amp;lt;ref name=&amp;quot;xssworms&amp;quot;&amp;gt;{{cite journal |last1 = Faghani|first1 = Mohamamd Reza| year=2013| title = A Study of XSS Worm Propagation and Detection Mechanisms in Online Social Networks | journal = IEEE Transactions on Information Forensics and Security|volume = 8|issue = 11|pages = 1815–1826|doi = 10.1109/TIFS.2013.2280884}}&amp;lt;/ref&amp;gt; but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
&lt;br /&gt;
Cross-clique centrality of a single node in a complex graph determines the connectivity of a node to different cliques. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in  but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
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复杂图中单个节点的跨团中心性决定了一个节点与不同团的连通性。具有高度跨团连通性的节点有利于信息或疾病在图中的传播。团是一种'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图Subgraphs&amp;lt;/font&amp;gt;'''，团中的每个节点都与团中的其他节点相连。对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边的交叉团连通性，定义为 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; x (v) &amp;lt;/math &amp;gt; 其中 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 所属的顶点团数。这个测度应用日久，但是在1998年由 Everett 和 Borgatti 首次提出，他们称之为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 派系重叠中心性Clique-overlap centrality&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Freeman centralization==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心度Freeman centralization&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
The '''centralization''' of any network is a measure of how central its most central node is in relation to how central all the other nodes are.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;&amp;gt;{{citation | journal = Social Networks | last1 = Freeman | first1 = Linton C. | year = 1979 | volume = 1 | issue = 3 | pages = 215–239 | title = centrality in social networks: Conceptual clarification | url = http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | doi = 10.1016/0378-8733(78)90021-7 | citeseerx = 10.1.1.227.9549 | access-date = 2014-07-31 | archive-url = https://web.archive.org/web/20160222033108/http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | archive-date = 2016-02-22 | url-status = dead }}&amp;lt;/ref&amp;gt; Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
&lt;br /&gt;
The centralization of any network is a measure of how central its most central node is in relation to how central all the other nodes are. Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
&lt;br /&gt;
任何网络的集中度都是衡量其最核心的节点相对于其他所有节点的集聚程度的标准。集中度的度量方法是: (a)计算网络中最中心的节点与所有其他节点之间的中心性差异之和; (b)将这个数量除以理论上相同规模的任何网络中这种差异之和的最大值。因此，每个中心性度量都可以有自己的集中性度量。正式定义，如果 &amp;lt; math &amp;gt; c _ x (p _ i) &amp;lt;/math &amp;gt; 是点 &amp;lt; math &amp;gt; i &amp;lt;/math &amp;gt; 的中心性度量，如果 &amp;lt; math &amp;gt; c _ x (p _ *) &amp;lt;/math &amp;gt; 是网络中最大的中心性度量，如果:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; max sum { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i) &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&lt;br /&gt;
&lt;br /&gt;
对于任何具有相同节点数的图来说，点中心性的最大差异是:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ x = frac { sum _ { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i)}{ max sum _ { i = 1 ^ { n } c _ x (p _ *)-c _ x (p _ i)} . &amp;lt;/math &amp;gt;&lt;br /&gt;
&lt;br /&gt;
== Dissimilarity based centrality measures ==&lt;br /&gt;
==基于相异性的中心性度量==&lt;br /&gt;
&lt;br /&gt;
[[File:Srep17095-f1.jpg|thumbnail|In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.]]&lt;br /&gt;
&lt;br /&gt;
In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.&lt;br /&gt;
&lt;br /&gt;
在图示的网络中，绿色节点和红色节点最不相似，因为它们之间不共享相邻节点。因此，绿色的节点比灰色的节点对中心性的贡献更大，因为红色的节点只能通过绿色访问蓝色的节点，而灰色的节点对于红色的节点是多余的，因为它可以直接访问每个灰色的节点，而不需要任何中介。&lt;br /&gt;
&lt;br /&gt;
In order to obtain better results in the ranking of the nodes of a given network,  in &amp;lt;ref&amp;gt;{{Cite journal|title = Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|journal = Scientific Reports|date = 2015-11-25|pmc = 4658528|pmid = 26603652|volume = 5|doi = 10.1038/srep17095|first = A. J.|last = Alvarez-Socorro|first2 = G. C.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz|pages=17095|bibcode = 2015NatSR...517095A}}&amp;lt;/ref&amp;gt; are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with [[eigenvector centrality]], calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
&lt;br /&gt;
In order to obtain better results in the ranking of the nodes of a given network,  in  are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with eigenvector centrality, calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
&lt;br /&gt;
为了在给定网络节点的排序中获得更好的结果，在复杂网络中使用了相异性度量(特定于分类和数据挖掘理论)来丰富中心性度量。特征向量中心性通过求解特征值问题来计算每个节点的中心性&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
数学，数学&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary [[Matrix similarity|dissimilarity]] matrix, defined through a dissimilitary measure, e.g., [[Jaccard index|Jaccard]] dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary dissimilarity matrix, defined through a dissimilitary measure, e.g., Jaccard dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
这里 &amp;lt; math &amp;gt; w { ij } = a { ij } d { ij } &amp;lt;/math &amp;gt; (coordinate-to-coordinate product)和 &amp;lt; math &amp;gt; d { ij } &amp;lt;/math &amp;gt; 是一个任意的不相似矩阵，通过一个双重军事度量来定义，例如，Jaccard 由&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1-dfrac { | v ^ { + }(i) cap v ^ { + }(j) | }{ | v ^ { + }(i) cup v ^ { + }(j) | } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
&lt;br /&gt;
Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
&lt;br /&gt;
这种度量允许我们量化每个节点对给定节点中心性的拓扑贡献(这就是为什么我们称之为贡献中心性) ，对那些相异性较大的节点有更多的权重/相关性，因为这些节点允许给定的节点访问那些它们自己不能直接访问的节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the [[Perron–Frobenius theorem]] to ensure that the above problem has a unique solution for ''λ'' = ''λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt;'' with '''c''' non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
&lt;br /&gt;
Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the Perron–Frobenius theorem to ensure that the above problem has a unique solution for λ = λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt; with c non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
&lt;br /&gt;
值得注意的是，&amp;lt; math &amp;gt; w &amp;lt;/math &amp;gt; 是非负的，因为 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; d &amp;lt;/math &amp;gt; 都是非负矩阵，所以我们可以使用 Perron 弗罗贝尼乌斯定理来确保上述问题对于 c 非负的 = &amp;lt; sub &amp;gt; max &amp;lt;/sub &amp;gt; 有唯一的解，这样我们就可以推断出网络中每个节点的中心性。因此，i-th 节点的中心性为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1{ n } sum { j = 1} ^ { n } w { ij } c { j } ，，，，，j = 1，cdots，n &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in &amp;lt;ref&amp;gt;{{Cite web|url = http://www.nature.com/article-assets/npg/srep/2015/151125/srep17095/extref/srep17095-s1.pdf|title = Supplementary Information for Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|date = |website = |publisher = Nature Publishing Group|last = Alvarez-Socorro|first = A.J.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz}}&amp;lt;/ref&amp;gt; obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in  obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是网络中的节点数。几个不同的措施和网络进行了测试，以获得在研究案例的改善的结果。&lt;br /&gt;
&lt;br /&gt;
==Extensions==&lt;br /&gt;
==扩展==&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality&amp;lt;ref&amp;gt;{{cite journal | last1 = Braha | first1 = D. | last2 = Bar-Yam | first2 = Y. | year = 2006 | title = From Centrality to Temporary Fame: Dynamic Centrality in Complex Networks | url = | journal = Complexity | volume = 12 | issue = 2| pages = 59–63 | doi=10.1002/cplx.20156| arxiv = physics/0611295 | bibcode = 2006Cmplx..12b..59B }}&amp;lt;/ref&amp;gt; in the context of time-dependent and temporal networks.&amp;lt;ref&amp;gt;{{cite journal | last1 = Hill | first1 = S.A. | last2 = Braha | first2 = D. | year = 2010 | title = Dynamic Model of Time-Dependent Complex Networks | url = | journal = Physical Review E | volume = 82 | issue = 4| page = 046105 | doi=10.1103/physreve.82.046105| pmid = 21230343 | arxiv = 0901.4407 | bibcode = 2010PhRvE..82d6105H }}&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Gross, T. and Sayama, H. (Eds.). 2009. ''Adaptive Networks: Theory, Models and Applications.'' Springer.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Holme, P. and Saramäki, J. 2013. ''Temporal Networks.'' Springer.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality in the context of time-dependent and temporal networks.&lt;br /&gt;
&lt;br /&gt;
经验和理论研究已经将静态网络中的中心性概念扩展到时间依赖网络和时间网络中的动态中心性。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&amp;lt;ref&amp;gt;{{cite journal | last1 = Opsahl | first1 = Tore | last2 = Agneessens | first2 = Filip | last3 = Skvoretz | first3 = John | title = Node centrality in weighted networks: Generalizing degree and shortest paths | doi = 10.1016/j.socnet.2010.03.006 | year = 2010 | pages = 245–251 | volume = 32 | journal = Social Networks | url = http://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | issue = 3 | access-date = 2010-04-23 | archive-url = https://web.archive.org/web/20180226080331/https://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | archive-date = 2018-02-26 | url-status = dead }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&lt;br /&gt;
&lt;br /&gt;
对加权网络的推广，见 Opsahl 等人。(2010).&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, '''group betweenness''' centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&amp;lt;ref name=&amp;quot;group1&amp;quot;&amp;gt;Everett, M. G. and Borgatti, S. P. (2005). Extending centrality. In P. J. Carrington, J. Scott and S. Wasserman (Eds.), ''Models and methods in social network analysis'' (pp. 57–76). New York: Cambridge University Press.&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;group2&amp;quot;&amp;gt;Puzis, R., Yagil, D., Elovici, Y., Braha, D. (2009).[http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf Collaborative attack on Internet users’ anonymity] {{Webarchive|url=https://web.archive.org/web/20131207133417/http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf |date=2013-12-07 }}, ''Internet Research'' '''19'''(1)&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, group betweenness centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&lt;br /&gt;
&lt;br /&gt;
中心性的概念也扩展到了群体层次。例如，组间的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''显示了连接穿过组的成对非组成员的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Geodesics &amp;lt;/font&amp;gt;'''的比例。&lt;br /&gt;
&lt;br /&gt;
==See also==&lt;br /&gt;
==又及==&lt;br /&gt;
* [[Alpha centrality]]&lt;br /&gt;
&lt;br /&gt;
* [[Core–periphery structure]]&lt;br /&gt;
&lt;br /&gt;
* [[Distance (graph theory)|Distance in graphs]]&lt;br /&gt;
&lt;br /&gt;
*阿尔法中心性&lt;br /&gt;
&lt;br /&gt;
*核心—外围结构&lt;br /&gt;
&lt;br /&gt;
*距离（图理论）图中的距离&lt;br /&gt;
&lt;br /&gt;
==Notes and references==&lt;br /&gt;
&lt;br /&gt;
{{Reflist}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Further reading==&lt;br /&gt;
拓展阅读&lt;br /&gt;
* Koschützki, D.; Lehmann, K. A.; Peeters, L.; Richter, S.; Tenfelde-Podehl, D. and Zlotowski, O. (2005) Centrality Indices. In Brandes, U. and Erlebach, T. (Eds.)  ''Network Analysis: Methodological Foundations'', pp.&amp;amp;nbsp;16–61, LNCS 3418, Springer-Verlag.&lt;br /&gt;
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[[Category:Graph theory]]&lt;br /&gt;
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Category:Graph theory&lt;br /&gt;
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分类: 图论&lt;br /&gt;
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[[Category:Graph algorithms]]&lt;br /&gt;
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Category:Graph algorithms&lt;br /&gt;
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分类: 图形算法&lt;br /&gt;
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[[Category:Algebraic graph theory]]&lt;br /&gt;
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Category:Algebraic graph theory&lt;br /&gt;
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分类: 代数图论&lt;br /&gt;
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[[Category:Networks]]&lt;br /&gt;
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Category:Networks&lt;br /&gt;
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分类: 网络&lt;br /&gt;
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Category:Network analysis&lt;br /&gt;
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分类: 网络分析&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Centrality]]. Its edit history can be viewed at [[网络中心性/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
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		<title>网络中心性</title>
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		<updated>2020-12-05T03:01:46Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：&lt;/p&gt;
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&lt;div&gt;此词条暂由水流心不竞初译，未经审校，带来阅读不便，请见谅。&lt;br /&gt;
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{{for|the statistical concept|Central tendency}}&lt;br /&gt;
{{Network Science}}&lt;br /&gt;
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In [[graph theory]] and [[network theory|network analysis]], indicators of '''centrality''' identify the most important [[vertex (graph theory)|vertices]] within a graph. Applications include identifying the most influential person(s) in a [[social network]], key infrastructure nodes in the [[Internet]] or [[urban network]]s, and [[super-spreader]]s of disease. Centrality concepts were first developed in [[social network analysis]], and many of the terms used to measure centrality reflect their [[sociology|sociological]] origin.&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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In graph theory and network analysis, indicators of centrality identify the most important vertices within a graph. Applications include identifying the most influential person(s) in a social network, key infrastructure nodes in the Internet or urban networks, and super-spreaders of disease. Centrality concepts were first developed in , and many of the terms used to measure centrality reflect their sociological origin.&lt;br /&gt;
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They should not be confused with [[node influence metric]]s, which seek to quantify the influence of every node in the network.&lt;br /&gt;
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They should not be confused with node influence metrics, which seek to quantify the influence of every node in the network.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;图论 graph theory &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络分析 network analysis &amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性 centrality &amp;lt;/font&amp;gt;'''指标用于识别图中最重要的顶点。其应用包括在社会网络中识别出最有影响力的个人，在因特网或城市网络中识别出最为关键的基础设施节点，以及识别疾病的超级传播者。中心性的概念最初由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;社会网络分析 social network analysis&amp;lt;/font&amp;gt;'''所发展，因此许多用于衡量中心性的术语都反映出了它们的社会学出身。&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;中心性不应与节点影响度相混淆，后者意在量化网络中每个节点的影响。&lt;br /&gt;
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==中心性指数的定义与特性Definition and characterization of centrality indices==&lt;br /&gt;
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Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性指数Centrality indices &amp;lt;/font&amp;gt;'''是对“重要顶点的特征是什么”这一问题的回答，答案以图顶点的实值函数的方式给出，在这些顶点上的取值的排序标识出最重要的节点。&lt;br /&gt;
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The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
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The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
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“重要性”这个词有许多含义，导致了许多不同的中心性定义。分为两类。&lt;br /&gt;
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&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important.&amp;lt;ref name=Borgatti2005/&amp;gt; &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt; Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important. Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&lt;br /&gt;
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“重要性”可以被认为与一种跨网络的流动或传输有关。这允许根据它们认为重要的流类型对中心性进行分类。这两种方法都将中心性划分为不同的类别。进一步的推论是，适用于一个类别的中心性在（推广）应用于另一个类别时往往会“出错”。&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one ([[Centrality#Degree centrality|degree centrality]]) to infinite walks ([[Centrality#Eigenvector centrality|eigenvalue centrality]]).&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=&amp;quot;Benzi2013&amp;quot;&amp;gt;{{cite journal | last1=Benzi | first1=Michele | last2=Klymko| first2=Christine | year=2013 |title= A matrix analysis of different centrality measures |arxiv=1312.6722 | doi=10.1137/130950550 | volume=36 | issue=2 | journal=SIAM Journal on Matrix Analysis and Applications | pages=686–706}}&amp;lt;/ref&amp;gt; The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one (degree centrality) to infinite walks (eigenvalue centrality). The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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当中心性按照它们对'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 内聚性Cohesiveness&amp;lt;/font&amp;gt;'''的趋近程度来分类时，很明显，大多数中心性都集中在一个类别中。从一个给定顶点开始对步数计数，不同之处只在于行走的定义和计数方式。对该组描述的约束限制，从位置中心（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心度Degree centrality&amp;lt;/font&amp;gt;'''）到单元域（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征中心度Eigenvalue centrality&amp;lt;/font&amp;gt;'''），观察到许多中心性都有这种相似关系，这也许可以解释这些指数之间的高阶相关性。&lt;br /&gt;
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===Characterization by network flows==&lt;br /&gt;
==网络流特征==&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at once.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at oe.&lt;br /&gt;
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一个网络可以被看成是对某种物体流动的路径描述。使基于流的类型和由中心性编码的路径类型（同时）得到表征。一个流可以基于传输，每个不可分割的项目从一个节点到另一个节点，就像一个包裹从配送站送到客户的房子。第二种情况是串行复制，在这种情况下，一个项从源节点被复制到达目标节点。例如通过流言传播信息，以私有方式传播信息，并在流程结束时通知源节点和目标节点。最后一种情况是并行复制，即同时将项目复制到多个链接，就像无线电广播一次性向多个听众提供相同的信息。&lt;br /&gt;
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Likewise, the type of path can be constrained to [[Distance (graph theory)|geodesics]] (shortest paths), [[Glossary of graph theory terms#path|paths]]  (no vertex is visited more than once), [[Glossary of graph theory terms#trail|trails]] (vertices can be visited multiple times, no edge is traversed more than once), or [[Glossary of graph theory terms#walk|walks]] (vertices and edges can be visited/traversed multiple times).&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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Likewise, the type of path can be constrained to geodesics (shortest paths), paths  (no vertex is visited more than once), trails (vertices can be visited multiple times, no edge is traversed more than once), or walks (vertices and edges can be visited/traversed multiple times).&lt;br /&gt;
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同样，路径类型可以被限定为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Distance &amp;lt;/font&amp;gt;'''(最短路径)、路径(对顶点的访问不超过一次)、小径(可以访问多次顶点，没有边被访问超过一次)或者步子(可以访问/遍历多次顶点和边)。&lt;br /&gt;
===Characterization by walk structure===&lt;br /&gt;
==行走结构特征==&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either ''radial'' or ''medial.'' Radial centralities count walks which start/end from the given vertex. The [[Centrality#Degree centrality|degree]] and [[Centrality#Eigenvector centrality|eigenvalue]] centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's [[Centrality#Betweenness centrality|betweenness]] centrality, the number of shortest paths which pass through the given vertex.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either radial or medial. Radial centralities count walks which start/end from the given vertex. The degree and eigenvalue centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's betweenness centrality, the number of shortest paths which pass through the given vertex.&lt;br /&gt;
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可以从中心性的构造方式推导出另一种分类方法。这又分成了两个类。中心点可以是放射状的，也可以是内侧的。从给定顶点开始/结束的径向中心点数。度和特征值中心是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 径向中心Radial centralities&amp;lt;/font&amp;gt;'''的例子，计算长度为一或无穷大的行走的个数。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中间中心性Medial centralities&amp;lt;/font&amp;gt;'''计算通过给定顶点的步数。典型的例子是 弗里曼的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality,&amp;lt;/font&amp;gt;'''，即穿过给定顶点的最短路径的数量。&lt;br /&gt;
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Likewise, the counting can capture either the ''volume'' or the ''length'' of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's [[Centrality#Closeness centrality|closeness]] centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example.&amp;lt;ref name=Borgatti2006/&amp;gt; Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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Likewise, the counting can capture either the volume or the length of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's closeness centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example. Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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同样地，计数可以抓住行走的体积或长度。体积是给定类型的行走的总数。上一段的三个例子就属于这一类。长度则给出从给定顶点到图中其余顶点的距离。弗里曼 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，即从一个给定顶点到所有其他顶点的测地距离，是最著名的例子。请注意，这种分类独立于步行计数的类型(即：步行，小道，路径，测地线)。&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&lt;br /&gt;
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博尔加蒂和埃弗雷特提出，这种类型学为如何最好地比较中心性度量提出了建议。在这个22分类中，放在同一盒子中的中心点足够相似，可以做出合理的选择; 人们可以合理地比较哪个对于给定的应用更好。然而，不同盒子中的度量方法是截然不同的。只有在预先确定哪个类别更适用的情况下，对相对适应性的评估才会发生，这使得比较变得毫无意义。&lt;br /&gt;
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===Radial-volume centralities exist on a spectrum===&lt;br /&gt;
==光谱上存在的径向体积中心==&lt;br /&gt;
The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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步行结构的特征表明，几乎所有广泛使用的中心性都是径向体积的衡量。这得出结论顶点的中心性是与之相关联的顶点中心性的函数。中心性根据如何定义关联而不同。&lt;br /&gt;
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Bonacich showed that if association is defined in terms of [[Glossary of graph theory terms#walk|walks]], then a family of centralities can be defined based on the length of walk considered.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;/&amp;gt; [[Centrality#Degree centrality|Degree centrality]] counts walks of length one, while [[Centrality#Eigenvector centrality|eigenvalue centrality]] counts walks of length infinity. Alternative definitions of association are also reasonable. [[Alpha centrality]] allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich showed that if association is defined in terms of walks, then a family of centralities can be defined based on the length of walk considered. Degree centrality counts walks of length one, while eigenvalue centrality counts walks of length infinity. Alternative definitions of association are also reasonable. Alpha centrality allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich 指出，如果联想是根据行走来定义的，那么可以根据考虑的行走长度来定义一个中心性家族。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''计算长度为1的行走，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征值中心性Eigenvalue centrality  &amp;lt;/font&amp;gt;'''计算长度为无穷大的行走。关联的其他定义也是合理的。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 阿尔法中心性Alpha centrality&amp;lt;/font&amp;gt;'''允许顶点有一个外部影响源。埃斯特拉达的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图中心性Subgraph centrality &amp;lt;/font&amp;gt;'''提出只计算封闭路径(三角形、正方形等)。).&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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这些测量方法的核心是这种现象：图中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵&amp;lt;/font&amp;gt;'''的幂给出了由该幂给出的散步长度的数目。同样，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 矩阵指数Matrix exponential&amp;lt;/font&amp;gt;'''也与给定长度的行走次数密切相关。邻接矩阵的初始转换允许对步行计数的类型进行不同的定义。无论采用哪种方法，顶点的中心性都可以表示为无穷和&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum _ { k = 0} ^ infty a _ { r } ^ { k } beta ^ k &amp;lt;/math &amp;gt; &lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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矩阵能量或者&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; sum { k = 0} ^ infty frac {(a _ r beta) ^ k }{ k！{/math &amp;gt; &lt;br /&gt;
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&lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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对于矩阵指数函数，其中&lt;br /&gt;
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* &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; is walk length,&lt;br /&gt;
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* &amp;lt;math&amp;gt;A_R&amp;lt;/math&amp;gt; is the transformed adjacency matrix, and&lt;br /&gt;
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* &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; is a discount parameter which ensures convergence of the sum.&lt;br /&gt;
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K为步长，A_R是邻接矩阵的转秩，贝达是保证收敛的折扣参数。&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. [[Alpha centrality]] replaces the adjacency matrix with its [[resolvent formalism|resolvent]]. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to [[Centrality#Degree centrality|degree centrality]]. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to [[Centrality#Eigenvector centrality|eigenvalue centrality]].&amp;lt;ref name=Benzi2013/&amp;gt;&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. Alpha centrality replaces the adjacency matrix with its resolvent. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to degree centrality. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to eigenvalue centrality.&lt;br /&gt;
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博纳奇的一系列措施并没有改变邻接矩阵。阿尔法集中性用它的解决方案替代了邻接矩阵。子图集中性用它的踪迹取代了邻接矩阵。一个令人吃惊的结论是，不管邻接矩阵最初的转变是什么，所有这些方法都有共同的限制行为。随着贝塔系数趋近于零，指数收敛到度中心性。随着贝塔系数接近其最大值，指数收敛到特征值的中心性。&lt;br /&gt;
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===Game-theoretic centrality===&lt;br /&gt;
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=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
&lt;br /&gt;
The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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上述大多数标准措施的共同特点是，它们通过只关注一个节点本身所扮演的角色来评估确定节点的重要性。然而, 在许多应用中，这种方法是不充分的，因为可能会发生协同作用&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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如果将节点的功能分组考虑。&lt;br /&gt;
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[[File:Game-theoretic centrality.png|Example of game-theoretic centrality]]&lt;br /&gt;
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Example of game-theoretic centrality&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''的例子&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in &amp;lt;ref&amp;gt;Michalak, Aadithya, Szczepański, Ravindran, &amp;amp; Jennings {{ArXiv|1402.0567}}&amp;lt;/ref&amp;gt; uses the [[Shapley value]]. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
&lt;br /&gt;
For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in  uses the Shapley value. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
&lt;br /&gt;
例如，考虑阻止流行病的问题。看看上面的网络图像，我们应该给哪些节点接种疫苗？基于前面描述的措施，我们希望识别在疾病传播中最重要的节点。仅仅基于中心的方法，即关注节点的个别特性，可能不是一个好主意。红色方块中的节点，单独不能阻止疾病的传播，但把它们作为一个群体来考虑，我们清楚地看到，如果疾病在节点 &amp;lt; math &amp;gt; v _ 1 &amp;lt;/math &amp;gt; 、 &amp;lt; math &amp;gt; v _ 4 &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; v _ 5 &amp;lt;/math &amp;gt; 中开始，它们就能阻止疾病的传播。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''试图利用博弈论中的工具来研究所描述的问题和机会。本文提出的方法使用了 Shapley 值。由于 Shapley 值计算的时间复杂性，这一领域的大部分工作都集中在实现新的算法和方法，这些算法和方法依赖于网络的特殊拓扑结构或问题的特殊性质。这种方法可以将时间复杂度从指数级降低到多项式级。&lt;br /&gt;
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Similarly, the solution concept [[authority distribution]] (&amp;lt;ref&amp;gt;{{cite journal |last=Hu |first=Xingwei |first2=Lloyd |last2=Shapley |title=On Authority Distributions in Organizations |journal=Games and Economic Behavior |volume=45 |pages=132–170 |year=2003 | doi = 10.1016/s0899-8256(03)00130-1 }}&amp;lt;/ref&amp;gt;) applies the [[Shapley-Shubik power index]], rather than the [[Shapley value]], to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020)&amp;lt;ref&amp;gt;{{cite journal|last=Hu|first=Xingwei|year=2020|volume=7|title=Sorting big data by revealed preference with application to college ranking |journal=Journal of Big Data|doi=10.1186/s40537-020-00300-1|doi-access=free}}&amp;lt;/ref&amp;gt;, such as ranking U.S. colleges.&lt;br /&gt;
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Similarly, the solution concept authority distribution () applies the Shapley-Shubik power index, rather than the Shapley value, to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020), such as ranking U.S. colleges.&lt;br /&gt;
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同样，'''&amp;lt;font color=&amp;quot;#CD32CD&amp;quot;&amp;gt; 加权分布概念的解()The solution concept authority distribution () &amp;lt;/font&amp;gt;'''采用 Shapley-Shubik 幂指数，而不是 Shapley 值来衡量双方之间的直接影响。这种分布确实是一种产生'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征向量中心性Engenvector centrality&amp;lt;/font&amp;gt;'''的类型。它用于对 Hu (2020)中的大数据对象进行排序，比如美国大学排名。&lt;br /&gt;
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== Important limitations ==&lt;br /&gt;
==重要限制==&lt;br /&gt;
Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the [[Krackhardt kite graph]], for which three different notions of centrality give three different choices of the most central vertex.&amp;lt;ref&amp;gt;{{cite journal|title=Assessing the Political Landscape: Structure, Cognition, and Power in Organizations|first=David|last=Krackhardt|authorlink=David Krackhardt|journal=Administrative Science Quarterly|volume=35|issue=2|date=June 1990|pages=342–369|doi=10.2307/2393394|jstor=2393394}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the Krackhardt kite graph, for which three different notions of centrality give three different choices of the most central vertex.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中心性Centrality&amp;lt;/font&amp;gt;'''指标有两个重要的局限性，一个显而易见，另一个则不易察觉。显而易见的局限性是，对于一个应用最优的中心性对于另一个应用常常是次优的。事实上，如果不是这样，我们就不需要这么多不同的中心性。克拉克哈特风筝图为这一现象提供了一个例证，对于这个图，三个不同的中心性概念给出了三个最中心顶点的不同选择。&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices.&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=Borgatti2005/&amp;gt; This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  [[node influence metric]]s to address this problem.&lt;br /&gt;
&lt;br /&gt;
The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices. This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  node influence metrics to address this problem.&lt;br /&gt;
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更不易察觉的限制是通常会错误地认为顶点中心性表示顶点的相对重要性。中心性指数被明确地设计来产生一个指出最重要顶点的排名。在刚才提到的限制下，他们做得很好。它们通常不用来测量节点的影响力。最近，网络物理学家开始开发'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;节点影响度量Node influence metrics &amp;lt;/font&amp;gt;'''来解决这个问题。&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying [[Centrality#Freeman centralization|Freeman centralization]] to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt; This approach, however, is seldom seen in practice.{{citation needed|reason=I've come across quite some theoretical studies that indicate otherwise. My suggestion is to remove this sentence, if reasonable citation is not provided.|date=September 2015}}&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying Freeman centralization to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores. This approach, however, is seldom seen in practice.&lt;br /&gt;
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错误有两方面。首先，一个排名只根据顶点的重要性排序，它并不对节点重要性的不同水平进行量化区分。这可以通过将 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;'''应用到中心性度量来缓解，这种度量可以根据节点的不同中心性得分来判断节点的重要性。此外， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;''使人们能够通过比较几个网络的最高中心性得分来比较它们。然而，这种方法在实践中很少见到。&lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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其次，用以(正确地)识别给定网络/应用中最重要顶点的特征并不一定可推广到其余顶点。&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot; /&amp;gt;&amp;lt;ref name=&amp;quot;daSilva2012&amp;quot;&amp;gt;{{cite journal | last1=da Silva|first1=Renato |last2=Viana|first2=Matheus|last3=da F. Costa |first3=Luciano| title=Predicting epidemic outbreak from individual features of the spreaders| journal=J. Stat. Mech.: Theory Exp. | year=2012|volume=2012|pages=P07005|number=7 | doi=10.1088/1742-5468/2012/07/p07005|arxiv=1202.0024|bibcode=2012JSMTE..07..005A}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Bauer2012&amp;quot;&amp;gt;{{cite journal | last1=Bauer|first1=Frank | last2=Lizier|first2=Joseph|title=Identifying influential spreaders and efficiently estimating infection numbers in epidemic models: A walk counting approach| journal=Europhys Lett | year=2012| volume=99| pages=68007|number=6 | doi=10.1209/0295-5075/99/68007|arxiv=1203.0502|bibcode=2012EL.....9968007B}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Sikic2013&amp;quot;&amp;gt;{{ cite journal| last1= Sikic| first1=Mile|last2=Lancic|first2=Alen|last3=Antulov-Fantulin|first3=Nino|last4=Stefanic|first4=Hrvoje| title = Epidemic centrality -- is there an underestimated epidemic impact of network peripheral nodes? |journal = The European Physical Journal B |volume=86 |number=10 |pages=1–13 |year=2013 | doi=10.1140/epjb/e2013-31025-5|arxiv=1110.2558 | bibcode=2013EPJB...86..440S}}&amp;lt;/ref&amp;gt; This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&amp;lt;ref name=&amp;quot;Ghoshal2011&amp;quot;&amp;gt;{{cite journal | last1=Ghoshal | first1= G. | last2= Barabsi |first2= A L | title = Ranking stability and super-stable nodes in complex networks. | journal = Nat Commun | volume =2 | page = 394| year= 2011 | doi=10.1038/ncomms1396 | pmid= 21772265 | bibcode=2011NatCo...2..394G | doi-access= free }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless. This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&lt;br /&gt;
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对于大多数其他网络节点，排名可能是没有意义的。这就解释了为什么，例如，只有谷歌图片搜索的前几个结果以合理的顺序出现。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页排名Pagerank&amp;lt;/font&amp;gt;'''是一个非常不稳定的度量，显示了在跳转参数小的调整之后频繁的秩逆转。&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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虽然中心性指数未能推广到网络的其他部分，乍看起来似乎是违反直觉的，但它直接遵循上述定义。&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot;&amp;gt;{{cite journal |last1= Lawyer |first1= Glenn |year= 2015 |title= Understanding the spreading power of all nodes in a network: a continuous-time perspective |journal=Sci Rep |volume=5|pages=8665|doi=10.1038/srep08665 |pmid=25727453 |pmc=4345333|arxiv=1405.6707|bibcode=2015NatSR...5E8665L}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&lt;br /&gt;
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复杂网络具有异构的拓扑结构。由于最佳度量取决于最重要顶点的网络结构，对于这些顶点最优的度量对于网络的其余部分是次优的。&lt;br /&gt;
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==Degree centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Degree (graph theory)}} &lt;br /&gt;
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[[File:6 centrality measures.png|thumb|right|300px|Examples of A) [[Betweenness centrality]], B) [[Closeness centrality]], C) [[Eigenvector centrality]], D) [[Degree centrality]], E) [[Centrality#Harmonic centrality|Harmonic centrality]] and F) [[Katz centrality]] of the same graph.]]&lt;br /&gt;
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Examples of A) [[Betweenness centrality, B) Closeness centrality, C) Eigenvector centrality, D) Degree centrality, E) Harmonic centrality and F) Katz centrality of the same graph.]]&lt;br /&gt;
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实例 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; a)[中介中心性A) [[Betweenness centrality,b)紧密中心性，B) Closeness centrality, c)特征向量中心性，C) Eigenvector centrality, d)度中心性，D) Degree centrality, e)调和中心性，E) Harmonic centrality andf) 卡兹Katz 中心性]F) Katz centrality .]]&amp;lt;/font&amp;gt;'''&lt;br /&gt;
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Historically first and conceptually simplest is '''degree centrality''', which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely [[indegree]] and [[outdegree]]. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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Historically first and conceptually simplest is degree centrality, which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely indegree and outdegree. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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历史上最简单的概念是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''，它定义为一个节点上发生的链接数量(即一个节点拥有的关系数量)。度可以根据节点捕获流经网络的任何东西(例如病毒或某些信息)的直接风险来解释。在有向网络的情况下(其中联系有方向) ，我们通常定义两个独立的度量，即 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度 Outdegree&amp;lt;/font&amp;gt;'''。因此，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度indegree&amp;lt;/font&amp;gt;'''是指向该节点的关系数，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度outdegree&amp;lt;/font&amp;gt;'''是指该节点指向其他节点的关系数。当关系与一些积极的方面如友谊或合作有关时， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''通常被解释为一种形式的受欢迎，而 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度Indegree&amp;lt;/font&amp;gt;'''则被解释为合群。&lt;br /&gt;
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&lt;br /&gt;
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The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
&lt;br /&gt;
The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
&lt;br /&gt;
对于给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边，度的中心性定义为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Calculating degree centrality for all the nodes in a graph takes [[big theta|&amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt;]] in a [[dense matrix|dense]] [[adjacency matrix]] representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a [[sparse matrix]] representation.&lt;br /&gt;
&lt;br /&gt;
Calculating degree centrality for all the nodes in a graph takes &amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt; in a dense adjacency matrix representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a sparse matrix representation.&lt;br /&gt;
&lt;br /&gt;
计算一个图中所有节点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''需要在图的稠密'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵Adjacency matrix &amp;lt;/font&amp;gt;'''表示中使用 Theta (v ^ 2) &amp;lt;/math &amp;gt; ，而在稀疏矩阵表示中使用 Theta (e) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of ''graph centralization''.&amp;lt;ref&amp;gt;Freeman, Linton C. &amp;quot;Centrality in social networks conceptual clarification.&amp;quot; Social networks 1.3 (1979): 215–239.&amp;lt;/ref&amp;gt; Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
&lt;br /&gt;
The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of graph centralization. Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
&lt;br /&gt;
节点级中心性的定义可以扩展到整个图，在这种情况下，我们指的是图的集中性。设 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 为 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''最高的节点。让 &amp;lt; math &amp;gt; x: = (y，z) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; | y | &amp;lt;/math &amp;gt; 节点连接图，最大化下列数量(&amp;lt; math &amp;gt; y * &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 中度最高的节点) :&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h = sum ^ { | y | }{ j = 1}[ c _ d (y *)-c _ d (y _ j)] &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
&lt;br /&gt;
Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
&lt;br /&gt;
相应地，图形 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''如下:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ h } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a [[star graph]]), and in this case&lt;br /&gt;
&lt;br /&gt;
The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a star graph), and in this case&lt;br /&gt;
&lt;br /&gt;
当图形 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 包含一个所有其他节点都连接的中心节点(一个星形图)时，&amp;lt; math &amp;gt; h &amp;lt;/math &amp;gt; 的值最大化，在这种情况下&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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:&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
(n-1)-1) = n ^ 2-3n + 2&lt;br /&gt;
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So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
所以，对于任意的图 &amp;lt; math &amp;gt; g: = (v，e) ，&amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ | v | ^ 2-3 | v | + 2} &amp;lt;/math &amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Closeness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Closeness centrality}}In a [[Connected component (graph theory)|connected]] [[Graph (discrete mathematics)|graph]], the [[Normalization (statistics)|normalized]] '''closeness centrality''' (or '''closeness''') of a node is the average length of the [[Shortest path problem|shortest path]] between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
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In a connected graph, the normalized closeness centrality (or closeness) of a node is the average length of the shortest path between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
&lt;br /&gt;
在连通图中，节点的标准'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''(或贴近性)是节点与图中所有其他节点之间最短路径的平均长度。因此，一个节点越是中心，它就越接近所有其他节点。&lt;br /&gt;
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Closeness was defined by [[Alex Bavelas]] (1950) as the [[Multiplicative inverse|reciprocal]] of the '''farness''',&amp;lt;ref&amp;gt;Alex Bavelas. Communication patterns in task-oriented groups. ''J. Acoust. Soc. Am'', '''22'''(6):725–730, 1950.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;{{cite journal|year=1966|title=The centrality index of a graph|url=|journal=Psychometrika|volume=31|issue=4|pages=581–603|doi=10.1007/bf02289527|pmid=5232444|hdl=10338.dmlcz/101401|last1=Sabidussi|first1=G|hdl-access=free}}&amp;lt;/ref&amp;gt; that is:&lt;br /&gt;
&lt;br /&gt;
Closeness was defined by Alex Bavelas (1950) as the reciprocal of the farness, that is:&lt;br /&gt;
&lt;br /&gt;
亚历克斯 · 巴维拉斯(1950)将亲密度定义为相对于距离的倒数，即:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
C (x) = frac {1}{ sum _ y d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the [[Distance (graph theory)|distance]] between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the distance between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; d (y，x) &amp;lt;/math &amp;gt; 是顶点 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; 之间的距离。然而，当谈到'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''时，人们通常会提到它的标准化形式，一般是以前的公式乘以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; ，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。这种调整允许比较不同大小图形的节点。&lt;br /&gt;
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&lt;br /&gt;
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Taking distances ''from'' or ''to'' all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in [[directed graph]]s (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
&lt;br /&gt;
Taking distances from or to all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in directed graphs (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
&lt;br /&gt;
从所有其他节点或到所有其他节点的距离在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 无向图Undirected graphs&amp;lt;/font&amp;gt;'''中是不相关的，但是在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 有向图Directed graphs&amp;lt;/font&amp;gt;'''中可能产生完全不同的结果(例如:一个网站可以从传出链接获得高的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，而从传入链接获得低的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''）。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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===Harmonic centrality===&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the '''harmonic centrality''' reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the harmonic centrality reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
在一个(不一定是连通的)图中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''反转了'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''定义中的和互反运算:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h (x) = sum { y neq x } frac {1}{ d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; 1/d (y，x) = 0 &amp;lt;/math &amp;gt; if there is no path from &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; to &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 。调和中心性可以通过除以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; 来标准化，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Harmonic centrality was proposed by [[Massimo Marchiori|Marchiori]] and [[Vito Latora|Latora]] (2000)&amp;lt;ref name=&amp;quot;marchiorilatora2000&amp;quot;&amp;gt;{{citation| journal = Physica A: Statistical Mechanics and Its Applications  | last1 = Marchiori | first1 = Massimo | last2 = Latora | first2 = Vito | year = 2000 | volume = 285 | issue = 3–4 | pages = 539–546 | title = Harmony in the small-world | doi=10.1016/s0378-4371(00)00311-3| arxiv = cond-mat/0008357 | bibcode = 2000PhyA..285..539M }}&amp;lt;/ref&amp;gt; and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot;&amp;lt;ref&amp;gt;{{cite journal|first1=Anthony|last1=Dekker|title=Conceptual Distance in Social Network Analysis|journal=Journal of Social Structure|volume=6|issue=3|year=2005|url=http://www.cmu.edu/joss/content/articles/volume6/dekker/index.html}}&amp;lt;/ref&amp;gt; and by Rochat (2009).&amp;lt;ref&amp;gt;{{cite conference  | author = Yannick Rochat  | title = Closeness centrality extended to unconnected graphs: The harmonic centrality index | conference = Applications of Social Network Analysis, ASNA 2009 | url = http://infoscience.epfl.ch/record/200525/files/%5bEN%5dASNA09.pdf }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Harmonic centrality was proposed by Marchiori and Latora (2000) and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot; and by Rochat (2009).&lt;br /&gt;
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调和中心性是由 Marchiori 和 Latora (2000)提出的，然后是 Dekker (2005)独立提出的，使用的名称是“有价值的中心性” ，Rochat (2009)。&lt;br /&gt;
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==Betweenness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Betweenness centrality}}&lt;br /&gt;
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[[File:Graph betweenness.svg|240px|right|thumb|Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.]]&lt;br /&gt;
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Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.&lt;br /&gt;
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色调(从红色 = 0到蓝色 = max)表示节点之间的距离。&lt;br /&gt;
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'''Betweenness''' is a centrality measure of a [[vertex (graph theory)|vertex]] within a [[Graph (discrete mathematics)|graph]] (there is also [[edge (graph theory)|edge]] betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by [[Linton Freeman]]&amp;lt;ref name=&amp;quot;freeman1977&amp;quot;&amp;gt;{{cite journal |last1 = Freeman |first1 = Linton | year=1977| title = A set of measures of centrality based upon betweenness | journal = Sociometry| volume=40|issue = 1 | pages=35–41 | doi=10.2307/3033543|jstor = 3033543 }}&amp;lt;/ref&amp;gt; In his conception, vertices that have a high probability to occur on a randomly chosen [[shortest path problem|shortest path]] between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
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Betweenness is a centrality measure of a vertex within a graph (there is also edge betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by Linton Freeman In his conception, vertices that have a high probability to occur on a randomly chosen shortest path between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
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中介性是图中顶点的中心性度量(也有边中介性，这里没有讨论)。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''量化了一个节点沿着其他两个节点之间的最短路径充当桥梁的次数。在林顿 · 弗里曼的概念中，在两个随机选择的顶点之间随机选择的最短路径上出现概率高的顶点具有很高的中介性。&lt;br /&gt;
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The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
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The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
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在一个图 &amp;lt; math &amp;gt; g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的顶点之间的距离计算如下:&lt;br /&gt;
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# For each pair of vertices (''s'',''t''), compute the [[Shortest path problem|shortest paths]] between them.&lt;br /&gt;
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 For each pair of vertices (s,t), compute the shortest paths between them.&lt;br /&gt;
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对于每一对顶点(s，t) ，计算它们之间的最短路径。&lt;br /&gt;
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# For each pair of vertices (''s'',''t''), determine the fraction of shortest paths that pass through the vertex in question (here, vertex ''v'').&lt;br /&gt;
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 For each pair of vertices (s,t), determine the fraction of shortest paths that pass through the vertex in question (here, vertex v).&lt;br /&gt;
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对于每对顶点(s，t) ，确定通过该顶点(这里是顶点 v)的最短路径的分数。&lt;br /&gt;
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# Sum this fraction over all pairs of vertices (''s'',''t'').&lt;br /&gt;
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 Sum this fraction over all pairs of vertices (s,t).&lt;br /&gt;
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对所有顶点对(s，t)求这个分数的和。&lt;br /&gt;
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More compactly the betweenness can be represented as:&amp;lt;ref name=&amp;quot;brandes&amp;quot;&amp;gt;{{cite journal |last1 = Brandes |first1 = Ulrik | year=2001 |title = A faster algorithm for betweenness centrality  | journal = Journal of Mathematical Sociology| volume=25|issue = 2 | pages=163–177| url = http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.11.2024 | accessdate = October 11, 2011| format = PDF | doi=10.1080/0022250x.2001.9990249|citeseerx = 10.1.1.11.2024 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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More compactly the betweenness can be represented as:&lt;br /&gt;
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更确切地说，两者之间的关系可以表示为:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
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{ math &amp;gt; c _ b (v) = sum _ { s neq v neq t in v } frac { sigma _ st }(v)}{ sigma _ st } &amp;lt;/math &amp;gt; &lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including ''v'', which for [[Digraph (mathematics)|directed graphs]] is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected [[Star (graph theory)|star graph]], the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including v, which for directed graphs is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected star graph, the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; sigma { st } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { st }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径数。有向图是 &amp;lt; math &amp;gt; (n-1)(n-2) &amp;lt;/math &amp;gt; ，无向图是 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; 。例如，在一个无向星图中，中心顶点(包含在每个可能的最短路径中)的中介性为 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; (1，如果标准化) ，而叶子(包含在没有最短路径中)的中介性为0。&lt;br /&gt;
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From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires [[Big O notation|&amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt;]] time with the [[Floyd–Warshall algorithm]]. However, on sparse graphs, [[Johnson's algorithm]] may be more efficient, taking [[Big O notation|&amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt;]] time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm&amp;lt;ref name=brandes/&amp;gt; which takes [[Big O notation|&amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt;]] time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&amp;lt;ref name=&amp;quot;brandes&amp;quot; /&amp;gt;&lt;br /&gt;
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From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires &amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt; time with the Floyd–Warshall algorithm. However, on sparse graphs, Johnson's algorithm may be more efficient, taking &amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt; time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm which takes &amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt; time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&lt;br /&gt;
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从计算的角度来看，图中所有顶点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介和紧密中心性Betweenness and Closeness centralities&amp;lt;/font&amp;gt;'''都涉及到计算图中所有顶点对之间的最短路径，这就需要用 Floyd-Warshall 算法计算时间。然而，对于稀疏图，约翰逊算法的效率可能更高，采用 &amp;lt; math &amp;gt; o (v ^ 2 log v + v e) &amp;lt;/math &amp;gt; 时间。在不加权图的情况下，可以用 Brandes 的算法进行计算，该算法需要 &amp;lt; math &amp;gt; o (v e) &amp;lt;/math &amp;gt; 时间。一般情况下，这些算法假定图是无向的，并且连通图中允许有圈和多条边。当专门处理网络图时，图通常没有环或多条边来维持简单的关系(其中的边表示两个人或顶点之间的联系)。在这种情况下，使用 Brandes 的算法将最终的中心性分数除以2来计算每条被重复计算的最短路径。&lt;br /&gt;
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==Eigenvector centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Eigenvector centrality}}&lt;br /&gt;
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'''Eigenvector centrality''' (also called '''eigencentrality''') is a measure of the influence of a [[node (networking)|node]] in a [[network (mathematics)|network]]. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&amp;lt;ref&amp;gt;{{cite journal|title = The mathematics of networks|url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf|author = M. E. J. Newman|accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;/&amp;gt; [[Google]]'s [[PageRank]] and the [[Katz centrality]] are variants of the eigenvector centrality.&amp;lt;ref name=&amp;quot;ams&amp;quot;&amp;gt;{{Cite web | url=http://www.ams.org/samplings/feature-column/fcarc-pagerank | title=American Mathematical Society}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Eigenvector centrality (also called eigencentrality) is a measure of the influence of a node in a network. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''(也称为特征中心性)是衡量网络中节点影响的一个指标。它将相对得分分配给网络中的所有节点，这是基于这样一个概念: 与得分较高的节点相比，与得分较低的节点相同的连接对所涉及的节点的得分贡献更大。&lt;br /&gt;
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=== Using the adjacency matrix to find eigenvector centrality ==&lt;br /&gt;
==使用'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''发现'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the [[adjacency matrix]], i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
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For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the adjacency matrix, i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
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对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 让 &amp;lt; math &amp;gt; a = (a { v，t }) &amp;lt;/math &amp;gt; 成为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''，即。如果顶点 &amp;lt; math &amp;gt; &amp;gt; v &amp;lt;/math &amp;gt; 与 math &amp;gt; t &amp;lt;/math &amp;gt; 相连，而 &amp;lt; math &amp;gt; a { v，t } = 0 &amp;lt;/math &amp;gt; 否则。顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分可以定义为:&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
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在 m (v)} x _ t = frac {1}{ lambda } sum { t in g } a { v，t } x _ t &amp;lt;/math &amp;gt; &lt;br /&gt;
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where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the [[eigenvector]] equation&lt;br /&gt;
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where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the eigenvector equation&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; m (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 和 &amp;lt; math &amp;gt; &amp;gt; lambda &amp;lt;/math &amp;gt; 的邻居集合。通过一个小的重新排列，这可以被重写成向量符号，作为特征向量方程&lt;br /&gt;
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:&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
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[ math &amp;gt; mathbf { Ax } = { lambda } mathbf { x } &amp;lt;/math &amp;gt; &lt;br /&gt;
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In general, there will be many different [[eigenvalue]]s &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the [[Perron–Frobenius theorem]]. This greatest eigenvalue results in the desired centrality measure.&amp;lt;ref&amp;gt;{{cite journal  | author = M. E. J. Newman  | title = The mathematics of networks  | url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf  | accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt; The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices ''n''. [[Power iteration]] is one of many [[eigenvalue algorithm]]s that may be used to find this dominant eigenvector.&amp;lt;ref name=&amp;quot;ams&amp;quot; /&amp;gt; Furthermore, this can be generalized so that the entries in ''A'' can be real numbers representing connection strengths, as in a [[stochastic matrix]].&lt;br /&gt;
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In general, there will be many different eigenvalues &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the Perron–Frobenius theorem. This greatest eigenvalue results in the desired centrality measure. The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices n. Power iteration is one of many eigenvalue algorithms that may be used to find this dominant eigenvector. Furthermore, this can be generalized so that the entries in A can be real numbers representing connection strengths, as in a stochastic matrix.&lt;br /&gt;
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一般情况下，存在许多不同的特征值，对于这些特征值存在一个非零特征向量解。由于邻接矩阵中的条目是非负的，所以由 Perron-弗罗贝尼乌斯定理得出，它有一个实的和正的唯一最大特征值。由这个最大的特征值得出期望的中心性度量。相关特征向量的 &amp;lt; math &amp;gt; v ^ { th } &amp;lt;/math &amp;gt; 分量给出了网络中顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分。特征向量只定义了一个公共因子，所以只有顶点中心的比例是明确定义的。要定义一个绝对分数，必须对特征向量进行标准化，例如，使所有顶点的和为1或顶点的总数n。此外，这可以通用，使得 a 中的条目可以是表示连接强度的真实数字，就像'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 随机矩阵Stochastic matrix&amp;lt;/font&amp;gt;'''中一样。&lt;br /&gt;
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==Katz centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Katz centrality}}&lt;br /&gt;
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'''Katz centrality'''&amp;lt;ref&amp;gt;Katz, L. 1953. A New Status Index Derived from Sociometric Index. Psychometrika, 39–43.&amp;lt;/ref&amp;gt; is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
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Katz centrality is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''是度中心性的推广。度中心性度量的是直接邻居的数量，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''度量的是通过一条路径可以连接的所有节点的数量，而远处节点的贡献会受到'''&amp;lt;font color=&amp;quot;#32CD32&amp;quot;&amp;gt; '削弱（惩罚？）Penalized&amp;lt;/font&amp;gt;''。在数学上，它被定义为&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[数学][数学]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; (0,1) &amp;lt;/math &amp;gt; 中的衰减因子。&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''可以看作是特征向量中心性的变体。Katz 中心性的另一种形式是&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
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(x _ j + 1) &lt;br /&gt;
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Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
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Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
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与特征向量中心性的表达式相比，&amp;lt; math &amp;gt; x _ j &amp;lt;/math &amp;gt; 被 &amp;lt; math &amp;gt; x _ j + 1所代替&lt;br /&gt;
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It is shown that&amp;lt;ref&amp;gt;{{cite journal | last1 = Bonacich | first1 = P | year = 1991 | title = Simultaneous group and individual centralities | url = | journal = Social Networks | volume = 13 | issue = 2| pages = 155–168 | doi=10.1016/0378-8733(91)90018-o}}&amp;lt;/ref&amp;gt; the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
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It is shown that the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
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结果表明，主特征向量(与 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; ，邻接矩阵的最大特征值相关)是 Katz 中心性的极限，因为 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 接近 &amp;lt; math &amp;gt; tfrac {1}{ lambda } &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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== PageRank centrality ==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页分布中心性PageRank&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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{{main|PageRank}}'''[[PageRank]]''' satisfies the following equation&lt;br /&gt;
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PageRank satisfies the following equation&lt;br /&gt;
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PageRank满足下面的等式&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
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1-alpha { n } ，&amp;lt;/math &amp;gt; &lt;br /&gt;
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where&lt;br /&gt;
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where&lt;br /&gt;
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其中&lt;br /&gt;
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:&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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[ math &amp;gt; l (j) = sum { i } a { ji } &amp;lt;/math &amp;gt; &lt;br /&gt;
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is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&amp;lt;ref&amp;gt;[http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf How does Google rank webpages?] {{webarchive | url= https://web.archive.org/web/20120131083328/http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf |date=January 31, 2012 }} 20Q: About Networked Life&amp;lt;/ref&amp;gt;&lt;br /&gt;
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is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&lt;br /&gt;
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是节点 &amp;lt; math &amp;gt; j &amp;lt;/math &amp;gt; (或有向图中出站链接的数量)的邻居数量。与特征向量中心性和 Katz 中心性相比，尺度因子 &amp;lt; math &amp;gt; l (j) &amp;lt;/math &amp;gt; 是一个主要的区别。PageRank 和特征向量中心性的另一个区别是 PageRank 向量是一个左手特征向量(注意因子 &amp;lt; math &amp;gt; a _ { ji } &amp;lt;/math &amp;gt; 具有相反的索引)。&lt;br /&gt;
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==Percolation centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&amp;lt;ref name=&amp;quot;piraveenan2013&amp;quot;&amp;gt;{{cite journal |last1 = Piraveenan |first1 = M. |last2 = Prokopenko |first2 = M.|last3 = Hossain|first3 = L. |year=2013| title = Percolation Centrality: Quantifying Graph-Theoretic Impact of Nodes during Percolation in Networks | journal = PLOS One | volume=8 | issue=1 | doi=10.1371/journal.pone.0053095 | pages=e53095 | pmid=23349699 | pmc=3551907| bibcode=2013PLoSO...853095P }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&lt;br /&gt;
&lt;br /&gt;
在复杂网络中，存在大量的中心性度量来确定单个节点的“重要性”。然而，这些度量单纯从拓扑学的角度来量化节点的重要性，节点的值并不以任何方式依赖于节点的状态。不管网络动态如何，它都保持不变。即使对于加权的两者之间的度量也是如此。然而，一个节点可能很好地位于'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''或其他中心性度量的中心位置，但可能不是位于有过滤的网络的上下文中的中心位置。在许多情况下，复杂网络中都会出现“传染”现象。例如，病毒或细菌感染可以通过人们的社交网络传播，也就是所谓的接触网络。还可以在更高的抽象层次上考虑疾病的传播问题，设想通过公路、铁路或空中连接起来的城镇或人口中心网络。计算机病毒可以通过计算机网络传播。关于商业活动和交易的谣言或新闻也可以通过人们的社交网络传播。在所有这些情况下，一种“传染病”在一个复杂网络的链接上传播，随着它的传播，无论是可恢复的还是不可恢复的，都会改变节点的“状态”。例如，在流行病学方案中，随着感染扩散，个人从”易感”状态转变为”受感染”状态。在上面的例子中，随着传染的扩散，每个节点可以采取的状态可以是二进制的(例如接收/没有接收到一条新闻)、离散的(易感/受感染/康复) ，甚至是连续的(例如一个城镇中受感染的人的比例) 。这些情景的共同特点是，传染的扩散导致网络中节点状态的改变。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''（PC)就是基于这个思想而提出的，它特别地衡量了节点在协助网络渗滤方面的重要性。这项措施是由 piraveanan 等人提出的。&lt;br /&gt;
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'''Percolation centrality''' is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
&lt;br /&gt;
Percolation centrality is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''定义为在给定时间内一个给定节点的过滤路径的比例。“渗滤路径”是一对节点之间的最短路径，其中源节点被渗滤(例如，被感染)。目标节点可以是过滤的或非过滤的，或处于部分过滤状态。&lt;br /&gt;
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:&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; PC ^ t (v) = frac {1}{ N-2} sum { s neq v neq r } frac { sigma { sr }(v)}{ sigma { sr }} frac { x ^ t }{ sum {[{ x ^ t } i }}}]}}-{ x ^ t }{ v } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; σ { sr } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; r &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { sr }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径的总数。在时间 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 时，节点的过滤状态用 &amp;lt; math &amp;gt; { x ^ t } _ i &amp;lt;/math &amp;gt; 表示，两个特殊情况是当 &amp;lt; math &amp;gt; { x ^ t } _ i = 0 &amp;lt;/math &amp;gt; 表示在时间上是非过滤状态，而当 &amp;lt; math &amp;gt; &amp;lt; x ^ t &amp;lt;/math &amp;gt; i = 1 &amp;lt;/math &amp;gt; 表示在时间上是完全过滤状态。两者之间的值表示部分过滤状态(例如，在一个城镇网络中，这是该城镇感染者的百分比)。&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in [[Big O notation|&amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt;]] time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is [[Big O notation|&amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;]].&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in &amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt; time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is &amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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渗流路径的权重取决于分配给源节点的渗流水平，前提是源节点的渗流水平越高，源节点的路径就越重要。因此，位于源自高渗滤节点的最短路径上的节点可能对渗滤更为重要。PC 的定义也可以扩展到包括目标节点的权重。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''计算运行在 &amp;lt; math &amp;gt; o (NM) &amp;lt;/math &amp;gt; 时间，采用了 Brandes 快速算法的有效实现，如果计算需要考虑目标节点的权重，最坏情况下时间为 &amp;lt; math &amp;gt; o (n ^ 3) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
&lt;br /&gt;
==Cross-clique centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 交叉团中心性Cross-clique centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
'''Cross-clique centrality''' of a single node in a complex graph determines the connectivity of a node to different [[clique (graph theory)|clique]]s. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in &amp;lt;ref name=&amp;quot;xssworms&amp;quot;&amp;gt;{{cite journal |last1 = Faghani|first1 = Mohamamd Reza| year=2013| title = A Study of XSS Worm Propagation and Detection Mechanisms in Online Social Networks | journal = IEEE Transactions on Information Forensics and Security|volume = 8|issue = 11|pages = 1815–1826|doi = 10.1109/TIFS.2013.2280884}}&amp;lt;/ref&amp;gt; but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
&lt;br /&gt;
Cross-clique centrality of a single node in a complex graph determines the connectivity of a node to different cliques. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in  but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
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复杂图中单个节点的跨团中心性决定了一个节点与不同团的连通性。具有高度跨团连通性的节点有利于信息或疾病在图中的传播。团是一种'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图Subgraphs&amp;lt;/font&amp;gt;'''，团中的每个节点都与团中的其他节点相连。对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边的交叉团连通性，定义为 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; x (v) &amp;lt;/math &amp;gt; 其中 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 所属的顶点团数。这个测度应用日久，但是在1998年由 Everett 和 Borgatti 首次提出，他们称之为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 派系重叠中心性Clique-overlap centrality&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
&lt;br /&gt;
==Freeman centralization==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心度Freeman centralization&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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The '''centralization''' of any network is a measure of how central its most central node is in relation to how central all the other nodes are.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;&amp;gt;{{citation | journal = Social Networks | last1 = Freeman | first1 = Linton C. | year = 1979 | volume = 1 | issue = 3 | pages = 215–239 | title = centrality in social networks: Conceptual clarification | url = http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | doi = 10.1016/0378-8733(78)90021-7 | citeseerx = 10.1.1.227.9549 | access-date = 2014-07-31 | archive-url = https://web.archive.org/web/20160222033108/http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | archive-date = 2016-02-22 | url-status = dead }}&amp;lt;/ref&amp;gt; Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
&lt;br /&gt;
The centralization of any network is a measure of how central its most central node is in relation to how central all the other nodes are. Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
&lt;br /&gt;
任何网络的集中度都是衡量其最核心的节点相对于其他所有节点的集聚程度的标准。集中度的度量方法是: (a)计算网络中最中心的节点与所有其他节点之间的中心性差异之和; (b)将这个数量除以理论上相同规模的任何网络中这种差异之和的最大值。因此，每个中心性度量都可以有自己的集中性度量。正式定义，如果 &amp;lt; math &amp;gt; c _ x (p _ i) &amp;lt;/math &amp;gt; 是点 &amp;lt; math &amp;gt; i &amp;lt;/math &amp;gt; 的中心性度量，如果 &amp;lt; math &amp;gt; c _ x (p _ *) &amp;lt;/math &amp;gt; 是网络中最大的中心性度量，如果:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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:&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; max sum { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i) &amp;lt;/math &amp;gt; &lt;br /&gt;
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is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&lt;br /&gt;
&lt;br /&gt;
对于任何具有相同节点数的图来说，点中心性的最大差异是:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; c _ x = frac { sum _ { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i)}{ max sum _ { i = 1 ^ { n } c _ x (p _ *)-c _ x (p _ i)} . &amp;lt;/math &amp;gt;&lt;br /&gt;
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== Dissimilarity based centrality measures ==&lt;br /&gt;
==基于相异性的中心性度量==&lt;br /&gt;
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[[File:Srep17095-f1.jpg|thumbnail|In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.]]&lt;br /&gt;
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In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.&lt;br /&gt;
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在图示的网络中，绿色节点和红色节点最不相似，因为它们之间不共享相邻节点。因此，绿色的节点比灰色的节点对中心性的贡献更大，因为红色的节点只能通过绿色访问蓝色的节点，而灰色的节点对于红色的节点是多余的，因为它可以直接访问每个灰色的节点，而不需要任何中介。&lt;br /&gt;
&lt;br /&gt;
In order to obtain better results in the ranking of the nodes of a given network,  in &amp;lt;ref&amp;gt;{{Cite journal|title = Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|journal = Scientific Reports|date = 2015-11-25|pmc = 4658528|pmid = 26603652|volume = 5|doi = 10.1038/srep17095|first = A. J.|last = Alvarez-Socorro|first2 = G. C.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz|pages=17095|bibcode = 2015NatSR...517095A}}&amp;lt;/ref&amp;gt; are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with [[eigenvector centrality]], calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
&lt;br /&gt;
In order to obtain better results in the ranking of the nodes of a given network,  in  are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with eigenvector centrality, calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
&lt;br /&gt;
为了在给定网络节点的排序中获得更好的结果，在复杂网络中使用了相异性度量(特定于分类和数据挖掘理论)来丰富中心性度量。特征向量中心性通过求解特征值问题来计算每个节点的中心性&lt;br /&gt;
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:&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
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数学，数学&lt;br /&gt;
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where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary [[Matrix similarity|dissimilarity]] matrix, defined through a dissimilitary measure, e.g., [[Jaccard index|Jaccard]] dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary dissimilarity matrix, defined through a dissimilitary measure, e.g., Jaccard dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
这里 &amp;lt; math &amp;gt; w { ij } = a { ij } d { ij } &amp;lt;/math &amp;gt; (coordinate-to-coordinate product)和 &amp;lt; math &amp;gt; d { ij } &amp;lt;/math &amp;gt; 是一个任意的不相似矩阵，通过一个双重军事度量来定义，例如，Jaccard 由&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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:&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
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1-dfrac { | v ^ { + }(i) cap v ^ { + }(j) | }{ | v ^ { + }(i) cup v ^ { + }(j) | } &amp;lt;/math &amp;gt; &lt;br /&gt;
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Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
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Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
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这种度量允许我们量化每个节点对给定节点中心性的拓扑贡献(这就是为什么我们称之为贡献中心性) ，对那些相异性较大的节点有更多的权重/相关性，因为这些节点允许给定的节点访问那些它们自己不能直接访问的节点。&lt;br /&gt;
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Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the [[Perron–Frobenius theorem]] to ensure that the above problem has a unique solution for ''λ'' = ''λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt;'' with '''c''' non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
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Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the Perron–Frobenius theorem to ensure that the above problem has a unique solution for λ = λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt; with c non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
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值得注意的是，&amp;lt; math &amp;gt; w &amp;lt;/math &amp;gt; 是非负的，因为 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; d &amp;lt;/math &amp;gt; 都是非负矩阵，所以我们可以使用 Perron 弗罗贝尼乌斯定理来确保上述问题对于 c 非负的 = &amp;lt; sub &amp;gt; max &amp;lt;/sub &amp;gt; 有唯一的解，这样我们就可以推断出网络中每个节点的中心性。因此，i-th 节点的中心性为&lt;br /&gt;
&lt;br /&gt;
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:&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
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1{ n } sum { j = 1} ^ { n } w { ij } c { j } ，，，，，j = 1，cdots，n &amp;lt;/math &amp;gt; &lt;br /&gt;
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&lt;br /&gt;
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where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in &amp;lt;ref&amp;gt;{{Cite web|url = http://www.nature.com/article-assets/npg/srep/2015/151125/srep17095/extref/srep17095-s1.pdf|title = Supplementary Information for Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|date = |website = |publisher = Nature Publishing Group|last = Alvarez-Socorro|first = A.J.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz}}&amp;lt;/ref&amp;gt; obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in  obtaining improved results in the studied cases.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是网络中的节点数。几个不同的措施和网络进行了测试，以获得在研究案例的改善的结果。&lt;br /&gt;
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==Extensions==&lt;br /&gt;
==扩展==&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality&amp;lt;ref&amp;gt;{{cite journal | last1 = Braha | first1 = D. | last2 = Bar-Yam | first2 = Y. | year = 2006 | title = From Centrality to Temporary Fame: Dynamic Centrality in Complex Networks | url = | journal = Complexity | volume = 12 | issue = 2| pages = 59–63 | doi=10.1002/cplx.20156| arxiv = physics/0611295 | bibcode = 2006Cmplx..12b..59B }}&amp;lt;/ref&amp;gt; in the context of time-dependent and temporal networks.&amp;lt;ref&amp;gt;{{cite journal | last1 = Hill | first1 = S.A. | last2 = Braha | first2 = D. | year = 2010 | title = Dynamic Model of Time-Dependent Complex Networks | url = | journal = Physical Review E | volume = 82 | issue = 4| page = 046105 | doi=10.1103/physreve.82.046105| pmid = 21230343 | arxiv = 0901.4407 | bibcode = 2010PhRvE..82d6105H }}&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Gross, T. and Sayama, H. (Eds.). 2009. ''Adaptive Networks: Theory, Models and Applications.'' Springer.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Holme, P. and Saramäki, J. 2013. ''Temporal Networks.'' Springer.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality in the context of time-dependent and temporal networks.&lt;br /&gt;
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经验和理论研究已经将静态网络中的中心性概念扩展到时间依赖网络和时间网络中的动态中心性。&lt;br /&gt;
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For generalizations to weighted networks, see Opsahl et al. (2010).&amp;lt;ref&amp;gt;{{cite journal | last1 = Opsahl | first1 = Tore | last2 = Agneessens | first2 = Filip | last3 = Skvoretz | first3 = John | title = Node centrality in weighted networks: Generalizing degree and shortest paths | doi = 10.1016/j.socnet.2010.03.006 | year = 2010 | pages = 245–251 | volume = 32 | journal = Social Networks | url = http://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | issue = 3 | access-date = 2010-04-23 | archive-url = https://web.archive.org/web/20180226080331/https://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | archive-date = 2018-02-26 | url-status = dead }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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For generalizations to weighted networks, see Opsahl et al. (2010).&lt;br /&gt;
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对加权网络的推广，见 Opsahl 等人。(2010).&lt;br /&gt;
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The concept of centrality was extended to a group level as well. For example, '''group betweenness''' centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&amp;lt;ref name=&amp;quot;group1&amp;quot;&amp;gt;Everett, M. G. and Borgatti, S. P. (2005). Extending centrality. In P. J. Carrington, J. Scott and S. Wasserman (Eds.), ''Models and methods in social network analysis'' (pp. 57–76). New York: Cambridge University Press.&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;group2&amp;quot;&amp;gt;Puzis, R., Yagil, D., Elovici, Y., Braha, D. (2009).[http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf Collaborative attack on Internet users’ anonymity] {{Webarchive|url=https://web.archive.org/web/20131207133417/http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf |date=2013-12-07 }}, ''Internet Research'' '''19'''(1)&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, group betweenness centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&lt;br /&gt;
&lt;br /&gt;
中心性的概念也扩展到了群体层次。例如，组间的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''显示了连接穿过组的成对非组成员的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Geodesics &amp;lt;/font&amp;gt;'''的比例。&lt;br /&gt;
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==See also==&lt;br /&gt;
==又及==&lt;br /&gt;
* [[Alpha centrality]]&lt;br /&gt;
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* [[Core–periphery structure]]&lt;br /&gt;
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* [[Distance (graph theory)|Distance in graphs]]&lt;br /&gt;
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*阿尔法中心性&lt;br /&gt;
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*核心—外围结构&lt;br /&gt;
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*距离（图理论）图中的距离&lt;br /&gt;
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==Notes and references==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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==Further reading==&lt;br /&gt;
拓展阅读&lt;br /&gt;
* Koschützki, D.; Lehmann, K. A.; Peeters, L.; Richter, S.; Tenfelde-Podehl, D. and Zlotowski, O. (2005) Centrality Indices. In Brandes, U. and Erlebach, T. (Eds.)  ''Network Analysis: Methodological Foundations'', pp.&amp;amp;nbsp;16–61, LNCS 3418, Springer-Verlag.&lt;br /&gt;
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[[Category:Graph theory]]&lt;br /&gt;
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Category:Graph theory&lt;br /&gt;
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分类: 图论&lt;br /&gt;
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[[Category:Graph algorithms]]&lt;br /&gt;
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Category:Graph algorithms&lt;br /&gt;
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分类: 图形算法&lt;br /&gt;
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[[Category:Algebraic graph theory]]&lt;br /&gt;
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Category:Algebraic graph theory&lt;br /&gt;
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分类: 代数图论&lt;br /&gt;
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[[Category:Networks]]&lt;br /&gt;
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Category:Networks&lt;br /&gt;
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分类: 网络&lt;br /&gt;
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[[Category:Network analysis]]&lt;br /&gt;
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Category:Network analysis&lt;br /&gt;
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分类: 网络分析&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Centrality]]. Its edit history can be viewed at [[网络中心性/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
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		<title>网络中心性</title>
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		<updated>2020-12-05T03:00:21Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* 中心性指数的定义与特性Definition and characterization of centrality indices */&lt;/p&gt;
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&lt;div&gt;此词条暂由水流心不竞初译，未经审校，带来阅读不便，请见谅。&lt;br /&gt;
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{{for|the statistical concept|Central tendency}}&lt;br /&gt;
{{Network Science}}&lt;br /&gt;
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In [[graph theory]] and [[network theory|network analysis]], indicators of '''centrality''' identify the most important [[vertex (graph theory)|vertices]] within a graph. Applications include identifying the most influential person(s) in a [[social network]], key infrastructure nodes in the [[Internet]] or [[urban network]]s, and [[super-spreader]]s of disease. Centrality concepts were first developed in [[social network analysis]], and many of the terms used to measure centrality reflect their [[sociology|sociological]] origin.&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;&lt;br /&gt;
In graph theory and network analysis, indicators of centrality identify the most important vertices within a graph. Applications include identifying the most influential person(s) in a social network, key infrastructure nodes in the Internet or urban networks, and super-spreaders of disease. Centrality concepts were first developed in , and many of the terms used to measure centrality reflect their sociological origin.&lt;br /&gt;
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They should not be confused with [[node influence metric]]s, which seek to quantify the influence of every node in the network.&lt;br /&gt;
They should not be confused with node influence metrics, which seek to quantify the influence of every node in the network.&lt;br /&gt;
&lt;br /&gt;
在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;图论 graph theory &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络分析 network analysis &amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性 centrality &amp;lt;/font&amp;gt;'''指标用于识别图中最重要的顶点。其应用包括在社会网络中识别出最有影响力的个人，在因特网或城市网络中识别出最为关键的基础设施节点，以及识别疾病的超级传播者。中心性的概念最初由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;社会网络分析 social network analysis&amp;lt;/font&amp;gt;'''所发展，因此许多用于衡量中心性的术语都反映出了它们的社会学出身。中心性不应与节点影响度相混淆，后者意在量化网络中每个节点的影响。&lt;br /&gt;
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==中心性指数的定义与特性Definition and characterization of centrality indices==&lt;br /&gt;
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Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性指数Centrality indices &amp;lt;/font&amp;gt;'''是对“重要顶点的特征是什么”这一问题的回答，答案以图顶点的实值函数的方式给出，在这些顶点上的取值的排序标识出最重要的节点。&lt;br /&gt;
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The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
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The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
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“重要性”这个词有许多含义，导致了许多不同的中心性定义。分为两类。&lt;br /&gt;
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&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important.&amp;lt;ref name=Borgatti2005/&amp;gt; &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt; Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important. Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&lt;br /&gt;
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“重要性”可以被认为与一种跨网络的流动或传输有关。这允许根据它们认为重要的流类型对中心性进行分类。这两种方法都将中心性划分为不同的类别。进一步的推论是，适用于一个类别的中心性在（推广）应用于另一个类别时往往会“出错”。&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one ([[Centrality#Degree centrality|degree centrality]]) to infinite walks ([[Centrality#Eigenvector centrality|eigenvalue centrality]]).&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=&amp;quot;Benzi2013&amp;quot;&amp;gt;{{cite journal | last1=Benzi | first1=Michele | last2=Klymko| first2=Christine | year=2013 |title= A matrix analysis of different centrality measures |arxiv=1312.6722 | doi=10.1137/130950550 | volume=36 | issue=2 | journal=SIAM Journal on Matrix Analysis and Applications | pages=686–706}}&amp;lt;/ref&amp;gt; The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one (degree centrality) to infinite walks (eigenvalue centrality). The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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当中心性按照它们对'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 内聚性Cohesiveness&amp;lt;/font&amp;gt;'''的趋近程度来分类时，很明显，大多数中心性都集中在一个类别中。从一个给定顶点开始对步数计数，不同之处只在于行走的定义和计数方式。对该组描述的约束限制，从位置中心（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心度Degree centrality&amp;lt;/font&amp;gt;'''）到单元域（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征中心度Eigenvalue centrality&amp;lt;/font&amp;gt;'''），观察到许多中心性都有这种相似关系，这也许可以解释这些指数之间的高阶相关性。&lt;br /&gt;
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===Characterization by network flows==&lt;br /&gt;
==网络流特征==&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at once.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at oe.&lt;br /&gt;
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一个网络可以被看成是对某种物体流动的路径描述。使基于流的类型和由中心性编码的路径类型（同时）得到表征。一个流可以基于传输，每个不可分割的项目从一个节点到另一个节点，就像一个包裹从配送站送到客户的房子。第二种情况是串行复制，在这种情况下，一个项从源节点被复制到达目标节点。例如通过流言传播信息，以私有方式传播信息，并在流程结束时通知源节点和目标节点。最后一种情况是并行复制，即同时将项目复制到多个链接，就像无线电广播一次性向多个听众提供相同的信息。&lt;br /&gt;
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Likewise, the type of path can be constrained to [[Distance (graph theory)|geodesics]] (shortest paths), [[Glossary of graph theory terms#path|paths]]  (no vertex is visited more than once), [[Glossary of graph theory terms#trail|trails]] (vertices can be visited multiple times, no edge is traversed more than once), or [[Glossary of graph theory terms#walk|walks]] (vertices and edges can be visited/traversed multiple times).&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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Likewise, the type of path can be constrained to geodesics (shortest paths), paths  (no vertex is visited more than once), trails (vertices can be visited multiple times, no edge is traversed more than once), or walks (vertices and edges can be visited/traversed multiple times).&lt;br /&gt;
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同样，路径类型可以被限定为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Distance &amp;lt;/font&amp;gt;'''(最短路径)、路径(对顶点的访问不超过一次)、小径(可以访问多次顶点，没有边被访问超过一次)或者步子(可以访问/遍历多次顶点和边)。&lt;br /&gt;
===Characterization by walk structure===&lt;br /&gt;
==行走结构特征==&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either ''radial'' or ''medial.'' Radial centralities count walks which start/end from the given vertex. The [[Centrality#Degree centrality|degree]] and [[Centrality#Eigenvector centrality|eigenvalue]] centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's [[Centrality#Betweenness centrality|betweenness]] centrality, the number of shortest paths which pass through the given vertex.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either radial or medial. Radial centralities count walks which start/end from the given vertex. The degree and eigenvalue centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's betweenness centrality, the number of shortest paths which pass through the given vertex.&lt;br /&gt;
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可以从中心性的构造方式推导出另一种分类方法。这又分成了两个类。中心点可以是放射状的，也可以是内侧的。从给定顶点开始/结束的径向中心点数。度和特征值中心是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 径向中心Radial centralities&amp;lt;/font&amp;gt;'''的例子，计算长度为一或无穷大的行走的个数。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中间中心性Medial centralities&amp;lt;/font&amp;gt;'''计算通过给定顶点的步数。典型的例子是 弗里曼的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality,&amp;lt;/font&amp;gt;'''，即穿过给定顶点的最短路径的数量。&lt;br /&gt;
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Likewise, the counting can capture either the ''volume'' or the ''length'' of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's [[Centrality#Closeness centrality|closeness]] centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example.&amp;lt;ref name=Borgatti2006/&amp;gt; Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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Likewise, the counting can capture either the volume or the length of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's closeness centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example. Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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同样地，计数可以抓住行走的体积或长度。体积是给定类型的行走的总数。上一段的三个例子就属于这一类。长度则给出从给定顶点到图中其余顶点的距离。弗里曼 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，即从一个给定顶点到所有其他顶点的测地距离，是最著名的例子。请注意，这种分类独立于步行计数的类型(即：步行，小道，路径，测地线)。&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&lt;br /&gt;
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博尔加蒂和埃弗雷特提出，这种类型学为如何最好地比较中心性度量提出了建议。在这个22分类中，放在同一盒子中的中心点足够相似，可以做出合理的选择; 人们可以合理地比较哪个对于给定的应用更好。然而，不同盒子中的度量方法是截然不同的。只有在预先确定哪个类别更适用的情况下，对相对适应性的评估才会发生，这使得比较变得毫无意义。&lt;br /&gt;
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===Radial-volume centralities exist on a spectrum===&lt;br /&gt;
==光谱上存在的径向体积中心==&lt;br /&gt;
The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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步行结构的特征表明，几乎所有广泛使用的中心性都是径向体积的衡量。这得出结论顶点的中心性是与之相关联的顶点中心性的函数。中心性根据如何定义关联而不同。&lt;br /&gt;
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Bonacich showed that if association is defined in terms of [[Glossary of graph theory terms#walk|walks]], then a family of centralities can be defined based on the length of walk considered.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;/&amp;gt; [[Centrality#Degree centrality|Degree centrality]] counts walks of length one, while [[Centrality#Eigenvector centrality|eigenvalue centrality]] counts walks of length infinity. Alternative definitions of association are also reasonable. [[Alpha centrality]] allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich showed that if association is defined in terms of walks, then a family of centralities can be defined based on the length of walk considered. Degree centrality counts walks of length one, while eigenvalue centrality counts walks of length infinity. Alternative definitions of association are also reasonable. Alpha centrality allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich 指出，如果联想是根据行走来定义的，那么可以根据考虑的行走长度来定义一个中心性家族。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''计算长度为1的行走，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征值中心性Eigenvalue centrality  &amp;lt;/font&amp;gt;'''计算长度为无穷大的行走。关联的其他定义也是合理的。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 阿尔法中心性Alpha centrality&amp;lt;/font&amp;gt;'''允许顶点有一个外部影响源。埃斯特拉达的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图中心性Subgraph centrality &amp;lt;/font&amp;gt;'''提出只计算封闭路径(三角形、正方形等)。).&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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这些测量方法的核心是这种现象：图中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵&amp;lt;/font&amp;gt;'''的幂给出了由该幂给出的散步长度的数目。同样，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 矩阵指数Matrix exponential&amp;lt;/font&amp;gt;'''也与给定长度的行走次数密切相关。邻接矩阵的初始转换允许对步行计数的类型进行不同的定义。无论采用哪种方法，顶点的中心性都可以表示为无穷和&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum _ { k = 0} ^ infty a _ { r } ^ { k } beta ^ k &amp;lt;/math &amp;gt; &lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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矩阵能量或者&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum { k = 0} ^ infty frac {(a _ r beta) ^ k }{ k！{/math &amp;gt; &lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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对于矩阵指数函数，其中&lt;br /&gt;
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* &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; is walk length,&lt;br /&gt;
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* &amp;lt;math&amp;gt;A_R&amp;lt;/math&amp;gt; is the transformed adjacency matrix, and&lt;br /&gt;
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* &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; is a discount parameter which ensures convergence of the sum.&lt;br /&gt;
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K为步长，A_R是邻接矩阵的转秩，贝达是保证收敛的折扣参数。&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. [[Alpha centrality]] replaces the adjacency matrix with its [[resolvent formalism|resolvent]]. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to [[Centrality#Degree centrality|degree centrality]]. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to [[Centrality#Eigenvector centrality|eigenvalue centrality]].&amp;lt;ref name=Benzi2013/&amp;gt;&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. Alpha centrality replaces the adjacency matrix with its resolvent. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to degree centrality. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to eigenvalue centrality.&lt;br /&gt;
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博纳奇的一系列措施并没有改变邻接矩阵。阿尔法集中性用它的解决方案替代了邻接矩阵。子图集中性用它的踪迹取代了邻接矩阵。一个令人吃惊的结论是，不管邻接矩阵最初的转变是什么，所有这些方法都有共同的限制行为。随着贝塔系数趋近于零，指数收敛到度中心性。随着贝塔系数接近其最大值，指数收敛到特征值的中心性。&lt;br /&gt;
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===Game-theoretic centrality===&lt;br /&gt;
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=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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上述大多数标准措施的共同特点是，它们通过只关注一个节点本身所扮演的角色来评估确定节点的重要性。然而, 在许多应用中，这种方法是不充分的，因为可能会发生协同作用&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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如果将节点的功能分组考虑。&lt;br /&gt;
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[[File:Game-theoretic centrality.png|Example of game-theoretic centrality]]&lt;br /&gt;
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Example of game-theoretic centrality&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''的例子&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in &amp;lt;ref&amp;gt;Michalak, Aadithya, Szczepański, Ravindran, &amp;amp; Jennings {{ArXiv|1402.0567}}&amp;lt;/ref&amp;gt; uses the [[Shapley value]]. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in  uses the Shapley value. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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例如，考虑阻止流行病的问题。看看上面的网络图像，我们应该给哪些节点接种疫苗？基于前面描述的措施，我们希望识别在疾病传播中最重要的节点。仅仅基于中心的方法，即关注节点的个别特性，可能不是一个好主意。红色方块中的节点，单独不能阻止疾病的传播，但把它们作为一个群体来考虑，我们清楚地看到，如果疾病在节点 &amp;lt; math &amp;gt; v _ 1 &amp;lt;/math &amp;gt; 、 &amp;lt; math &amp;gt; v _ 4 &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; v _ 5 &amp;lt;/math &amp;gt; 中开始，它们就能阻止疾病的传播。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''试图利用博弈论中的工具来研究所描述的问题和机会。本文提出的方法使用了 Shapley 值。由于 Shapley 值计算的时间复杂性，这一领域的大部分工作都集中在实现新的算法和方法，这些算法和方法依赖于网络的特殊拓扑结构或问题的特殊性质。这种方法可以将时间复杂度从指数级降低到多项式级。&lt;br /&gt;
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Similarly, the solution concept [[authority distribution]] (&amp;lt;ref&amp;gt;{{cite journal |last=Hu |first=Xingwei |first2=Lloyd |last2=Shapley |title=On Authority Distributions in Organizations |journal=Games and Economic Behavior |volume=45 |pages=132–170 |year=2003 | doi = 10.1016/s0899-8256(03)00130-1 }}&amp;lt;/ref&amp;gt;) applies the [[Shapley-Shubik power index]], rather than the [[Shapley value]], to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020)&amp;lt;ref&amp;gt;{{cite journal|last=Hu|first=Xingwei|year=2020|volume=7|title=Sorting big data by revealed preference with application to college ranking |journal=Journal of Big Data|doi=10.1186/s40537-020-00300-1|doi-access=free}}&amp;lt;/ref&amp;gt;, such as ranking U.S. colleges.&lt;br /&gt;
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Similarly, the solution concept authority distribution () applies the Shapley-Shubik power index, rather than the Shapley value, to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020), such as ranking U.S. colleges.&lt;br /&gt;
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同样，'''&amp;lt;font color=&amp;quot;#CD32CD&amp;quot;&amp;gt; 加权分布概念的解()The solution concept authority distribution () &amp;lt;/font&amp;gt;'''采用 Shapley-Shubik 幂指数，而不是 Shapley 值来衡量双方之间的直接影响。这种分布确实是一种产生'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征向量中心性Engenvector centrality&amp;lt;/font&amp;gt;'''的类型。它用于对 Hu (2020)中的大数据对象进行排序，比如美国大学排名。&lt;br /&gt;
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== Important limitations ==&lt;br /&gt;
==重要限制==&lt;br /&gt;
Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the [[Krackhardt kite graph]], for which three different notions of centrality give three different choices of the most central vertex.&amp;lt;ref&amp;gt;{{cite journal|title=Assessing the Political Landscape: Structure, Cognition, and Power in Organizations|first=David|last=Krackhardt|authorlink=David Krackhardt|journal=Administrative Science Quarterly|volume=35|issue=2|date=June 1990|pages=342–369|doi=10.2307/2393394|jstor=2393394}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the Krackhardt kite graph, for which three different notions of centrality give three different choices of the most central vertex.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中心性Centrality&amp;lt;/font&amp;gt;'''指标有两个重要的局限性，一个显而易见，另一个则不易察觉。显而易见的局限性是，对于一个应用最优的中心性对于另一个应用常常是次优的。事实上，如果不是这样，我们就不需要这么多不同的中心性。克拉克哈特风筝图为这一现象提供了一个例证，对于这个图，三个不同的中心性概念给出了三个最中心顶点的不同选择。&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices.&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=Borgatti2005/&amp;gt; This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  [[node influence metric]]s to address this problem.&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices. This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  node influence metrics to address this problem.&lt;br /&gt;
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更不易察觉的限制是通常会错误地认为顶点中心性表示顶点的相对重要性。中心性指数被明确地设计来产生一个指出最重要顶点的排名。在刚才提到的限制下，他们做得很好。它们通常不用来测量节点的影响力。最近，网络物理学家开始开发'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;节点影响度量Node influence metrics &amp;lt;/font&amp;gt;'''来解决这个问题。&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying [[Centrality#Freeman centralization|Freeman centralization]] to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt; This approach, however, is seldom seen in practice.{{citation needed|reason=I've come across quite some theoretical studies that indicate otherwise. My suggestion is to remove this sentence, if reasonable citation is not provided.|date=September 2015}}&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying Freeman centralization to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores. This approach, however, is seldom seen in practice.&lt;br /&gt;
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错误有两方面。首先，一个排名只根据顶点的重要性排序，它并不对节点重要性的不同水平进行量化区分。这可以通过将 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;'''应用到中心性度量来缓解，这种度量可以根据节点的不同中心性得分来判断节点的重要性。此外， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;''使人们能够通过比较几个网络的最高中心性得分来比较它们。然而，这种方法在实践中很少见到。&lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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其次，用以(正确地)识别给定网络/应用中最重要顶点的特征并不一定可推广到其余顶点。&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot; /&amp;gt;&amp;lt;ref name=&amp;quot;daSilva2012&amp;quot;&amp;gt;{{cite journal | last1=da Silva|first1=Renato |last2=Viana|first2=Matheus|last3=da F. Costa |first3=Luciano| title=Predicting epidemic outbreak from individual features of the spreaders| journal=J. Stat. Mech.: Theory Exp. | year=2012|volume=2012|pages=P07005|number=7 | doi=10.1088/1742-5468/2012/07/p07005|arxiv=1202.0024|bibcode=2012JSMTE..07..005A}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Bauer2012&amp;quot;&amp;gt;{{cite journal | last1=Bauer|first1=Frank | last2=Lizier|first2=Joseph|title=Identifying influential spreaders and efficiently estimating infection numbers in epidemic models: A walk counting approach| journal=Europhys Lett | year=2012| volume=99| pages=68007|number=6 | doi=10.1209/0295-5075/99/68007|arxiv=1203.0502|bibcode=2012EL.....9968007B}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Sikic2013&amp;quot;&amp;gt;{{ cite journal| last1= Sikic| first1=Mile|last2=Lancic|first2=Alen|last3=Antulov-Fantulin|first3=Nino|last4=Stefanic|first4=Hrvoje| title = Epidemic centrality -- is there an underestimated epidemic impact of network peripheral nodes? |journal = The European Physical Journal B |volume=86 |number=10 |pages=1–13 |year=2013 | doi=10.1140/epjb/e2013-31025-5|arxiv=1110.2558 | bibcode=2013EPJB...86..440S}}&amp;lt;/ref&amp;gt; This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&amp;lt;ref name=&amp;quot;Ghoshal2011&amp;quot;&amp;gt;{{cite journal | last1=Ghoshal | first1= G. | last2= Barabsi |first2= A L | title = Ranking stability and super-stable nodes in complex networks. | journal = Nat Commun | volume =2 | page = 394| year= 2011 | doi=10.1038/ncomms1396 | pmid= 21772265 | bibcode=2011NatCo...2..394G | doi-access= free }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless. This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&lt;br /&gt;
&lt;br /&gt;
对于大多数其他网络节点，排名可能是没有意义的。这就解释了为什么，例如，只有谷歌图片搜索的前几个结果以合理的顺序出现。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页排名Pagerank&amp;lt;/font&amp;gt;'''是一个非常不稳定的度量，显示了在跳转参数小的调整之后频繁的秩逆转。&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
&lt;br /&gt;
While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
&lt;br /&gt;
虽然中心性指数未能推广到网络的其他部分，乍看起来似乎是违反直觉的，但它直接遵循上述定义。&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot;&amp;gt;{{cite journal |last1= Lawyer |first1= Glenn |year= 2015 |title= Understanding the spreading power of all nodes in a network: a continuous-time perspective |journal=Sci Rep |volume=5|pages=8665|doi=10.1038/srep08665 |pmid=25727453 |pmc=4345333|arxiv=1405.6707|bibcode=2015NatSR...5E8665L}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&lt;br /&gt;
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复杂网络具有异构的拓扑结构。由于最佳度量取决于最重要顶点的网络结构，对于这些顶点最优的度量对于网络的其余部分是次优的。&lt;br /&gt;
&lt;br /&gt;
==Degree centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Degree (graph theory)}} &lt;br /&gt;
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[[File:6 centrality measures.png|thumb|right|300px|Examples of A) [[Betweenness centrality]], B) [[Closeness centrality]], C) [[Eigenvector centrality]], D) [[Degree centrality]], E) [[Centrality#Harmonic centrality|Harmonic centrality]] and F) [[Katz centrality]] of the same graph.]]&lt;br /&gt;
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Examples of A) [[Betweenness centrality, B) Closeness centrality, C) Eigenvector centrality, D) Degree centrality, E) Harmonic centrality and F) Katz centrality of the same graph.]]&lt;br /&gt;
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实例 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; a)[中介中心性A) [[Betweenness centrality,b)紧密中心性，B) Closeness centrality, c)特征向量中心性，C) Eigenvector centrality, d)度中心性，D) Degree centrality, e)调和中心性，E) Harmonic centrality andf) 卡兹Katz 中心性]F) Katz centrality .]]&amp;lt;/font&amp;gt;'''&lt;br /&gt;
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Historically first and conceptually simplest is '''degree centrality''', which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely [[indegree]] and [[outdegree]]. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
&lt;br /&gt;
Historically first and conceptually simplest is degree centrality, which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely indegree and outdegree. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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历史上最简单的概念是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''，它定义为一个节点上发生的链接数量(即一个节点拥有的关系数量)。度可以根据节点捕获流经网络的任何东西(例如病毒或某些信息)的直接风险来解释。在有向网络的情况下(其中联系有方向) ，我们通常定义两个独立的度量，即 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度 Outdegree&amp;lt;/font&amp;gt;'''。因此，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度indegree&amp;lt;/font&amp;gt;'''是指向该节点的关系数，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度outdegree&amp;lt;/font&amp;gt;'''是指该节点指向其他节点的关系数。当关系与一些积极的方面如友谊或合作有关时， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''通常被解释为一种形式的受欢迎，而 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度Indegree&amp;lt;/font&amp;gt;'''则被解释为合群。&lt;br /&gt;
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The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
&lt;br /&gt;
The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
&lt;br /&gt;
对于给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边，度的中心性定义为&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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Calculating degree centrality for all the nodes in a graph takes [[big theta|&amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt;]] in a [[dense matrix|dense]] [[adjacency matrix]] representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a [[sparse matrix]] representation.&lt;br /&gt;
&lt;br /&gt;
Calculating degree centrality for all the nodes in a graph takes &amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt; in a dense adjacency matrix representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a sparse matrix representation.&lt;br /&gt;
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计算一个图中所有节点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''需要在图的稠密'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵Adjacency matrix &amp;lt;/font&amp;gt;'''表示中使用 Theta (v ^ 2) &amp;lt;/math &amp;gt; ，而在稀疏矩阵表示中使用 Theta (e) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of ''graph centralization''.&amp;lt;ref&amp;gt;Freeman, Linton C. &amp;quot;Centrality in social networks conceptual clarification.&amp;quot; Social networks 1.3 (1979): 215–239.&amp;lt;/ref&amp;gt; Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
&lt;br /&gt;
The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of graph centralization. Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
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节点级中心性的定义可以扩展到整个图，在这种情况下，我们指的是图的集中性。设 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 为 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''最高的节点。让 &amp;lt; math &amp;gt; x: = (y，z) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; | y | &amp;lt;/math &amp;gt; 节点连接图，最大化下列数量(&amp;lt; math &amp;gt; y * &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 中度最高的节点) :&lt;br /&gt;
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:&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; h = sum ^ { | y | }{ j = 1}[ c _ d (y *)-c _ d (y _ j)] &amp;lt;/math &amp;gt; &lt;br /&gt;
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Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
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Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
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相应地，图形 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''如下:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ h } &amp;lt;/math &amp;gt; &lt;br /&gt;
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The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a [[star graph]]), and in this case&lt;br /&gt;
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The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a star graph), and in this case&lt;br /&gt;
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当图形 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 包含一个所有其他节点都连接的中心节点(一个星形图)时，&amp;lt; math &amp;gt; h &amp;lt;/math &amp;gt; 的值最大化，在这种情况下&lt;br /&gt;
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:&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
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(n-1)-1) = n ^ 2-3n + 2&lt;br /&gt;
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So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
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So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
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所以，对于任意的图 &amp;lt; math &amp;gt; g: = (v，e) ，&amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ | v | ^ 2-3 | v | + 2} &amp;lt;/math &amp;gt;&lt;br /&gt;
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==Closeness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Closeness centrality}}In a [[Connected component (graph theory)|connected]] [[Graph (discrete mathematics)|graph]], the [[Normalization (statistics)|normalized]] '''closeness centrality''' (or '''closeness''') of a node is the average length of the [[Shortest path problem|shortest path]] between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
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In a connected graph, the normalized closeness centrality (or closeness) of a node is the average length of the shortest path between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
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在连通图中，节点的标准'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''(或贴近性)是节点与图中所有其他节点之间最短路径的平均长度。因此，一个节点越是中心，它就越接近所有其他节点。&lt;br /&gt;
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Closeness was defined by [[Alex Bavelas]] (1950) as the [[Multiplicative inverse|reciprocal]] of the '''farness''',&amp;lt;ref&amp;gt;Alex Bavelas. Communication patterns in task-oriented groups. ''J. Acoust. Soc. Am'', '''22'''(6):725–730, 1950.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;{{cite journal|year=1966|title=The centrality index of a graph|url=|journal=Psychometrika|volume=31|issue=4|pages=581–603|doi=10.1007/bf02289527|pmid=5232444|hdl=10338.dmlcz/101401|last1=Sabidussi|first1=G|hdl-access=free}}&amp;lt;/ref&amp;gt; that is:&lt;br /&gt;
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Closeness was defined by Alex Bavelas (1950) as the reciprocal of the farness, that is:&lt;br /&gt;
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亚历克斯 · 巴维拉斯(1950)将亲密度定义为相对于距离的倒数，即:&lt;br /&gt;
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&lt;br /&gt;
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: &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
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 &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
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C (x) = frac {1}{ sum _ y d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the [[Distance (graph theory)|distance]] between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the distance between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; d (y，x) &amp;lt;/math &amp;gt; 是顶点 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; 之间的距离。然而，当谈到'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''时，人们通常会提到它的标准化形式，一般是以前的公式乘以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; ，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。这种调整允许比较不同大小图形的节点。&lt;br /&gt;
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Taking distances ''from'' or ''to'' all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in [[directed graph]]s (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
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Taking distances from or to all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in directed graphs (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
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从所有其他节点或到所有其他节点的距离在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 无向图Undirected graphs&amp;lt;/font&amp;gt;'''中是不相关的，但是在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 有向图Directed graphs&amp;lt;/font&amp;gt;'''中可能产生完全不同的结果(例如:一个网站可以从传出链接获得高的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，而从传入链接获得低的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''）。&lt;br /&gt;
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===Harmonic centrality===&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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In a (not necessarily connected) graph, the '''harmonic centrality''' reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
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In a (not necessarily connected) graph, the harmonic centrality reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
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在一个(不一定是连通的)图中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''反转了'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''定义中的和互反运算:&lt;br /&gt;
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: &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
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 &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; h (x) = sum { y neq x } frac {1}{ d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
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where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
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where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; 1/d (y，x) = 0 &amp;lt;/math &amp;gt; if there is no path from &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; to &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 。调和中心性可以通过除以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; 来标准化，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。&lt;br /&gt;
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Harmonic centrality was proposed by [[Massimo Marchiori|Marchiori]] and [[Vito Latora|Latora]] (2000)&amp;lt;ref name=&amp;quot;marchiorilatora2000&amp;quot;&amp;gt;{{citation| journal = Physica A: Statistical Mechanics and Its Applications  | last1 = Marchiori | first1 = Massimo | last2 = Latora | first2 = Vito | year = 2000 | volume = 285 | issue = 3–4 | pages = 539–546 | title = Harmony in the small-world | doi=10.1016/s0378-4371(00)00311-3| arxiv = cond-mat/0008357 | bibcode = 2000PhyA..285..539M }}&amp;lt;/ref&amp;gt; and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot;&amp;lt;ref&amp;gt;{{cite journal|first1=Anthony|last1=Dekker|title=Conceptual Distance in Social Network Analysis|journal=Journal of Social Structure|volume=6|issue=3|year=2005|url=http://www.cmu.edu/joss/content/articles/volume6/dekker/index.html}}&amp;lt;/ref&amp;gt; and by Rochat (2009).&amp;lt;ref&amp;gt;{{cite conference  | author = Yannick Rochat  | title = Closeness centrality extended to unconnected graphs: The harmonic centrality index | conference = Applications of Social Network Analysis, ASNA 2009 | url = http://infoscience.epfl.ch/record/200525/files/%5bEN%5dASNA09.pdf }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Harmonic centrality was proposed by Marchiori and Latora (2000) and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot; and by Rochat (2009).&lt;br /&gt;
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调和中心性是由 Marchiori 和 Latora (2000)提出的，然后是 Dekker (2005)独立提出的，使用的名称是“有价值的中心性” ，Rochat (2009)。&lt;br /&gt;
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==Betweenness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Betweenness centrality}}&lt;br /&gt;
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[[File:Graph betweenness.svg|240px|right|thumb|Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.]]&lt;br /&gt;
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Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.&lt;br /&gt;
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色调(从红色 = 0到蓝色 = max)表示节点之间的距离。&lt;br /&gt;
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'''Betweenness''' is a centrality measure of a [[vertex (graph theory)|vertex]] within a [[Graph (discrete mathematics)|graph]] (there is also [[edge (graph theory)|edge]] betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by [[Linton Freeman]]&amp;lt;ref name=&amp;quot;freeman1977&amp;quot;&amp;gt;{{cite journal |last1 = Freeman |first1 = Linton | year=1977| title = A set of measures of centrality based upon betweenness | journal = Sociometry| volume=40|issue = 1 | pages=35–41 | doi=10.2307/3033543|jstor = 3033543 }}&amp;lt;/ref&amp;gt; In his conception, vertices that have a high probability to occur on a randomly chosen [[shortest path problem|shortest path]] between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
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Betweenness is a centrality measure of a vertex within a graph (there is also edge betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by Linton Freeman In his conception, vertices that have a high probability to occur on a randomly chosen shortest path between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
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中介性是图中顶点的中心性度量(也有边中介性，这里没有讨论)。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''量化了一个节点沿着其他两个节点之间的最短路径充当桥梁的次数。在林顿 · 弗里曼的概念中，在两个随机选择的顶点之间随机选择的最短路径上出现概率高的顶点具有很高的中介性。&lt;br /&gt;
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The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
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The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
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在一个图 &amp;lt; math &amp;gt; g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的顶点之间的距离计算如下:&lt;br /&gt;
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# For each pair of vertices (''s'',''t''), compute the [[Shortest path problem|shortest paths]] between them.&lt;br /&gt;
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 For each pair of vertices (s,t), compute the shortest paths between them.&lt;br /&gt;
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对于每一对顶点(s，t) ，计算它们之间的最短路径。&lt;br /&gt;
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# For each pair of vertices (''s'',''t''), determine the fraction of shortest paths that pass through the vertex in question (here, vertex ''v'').&lt;br /&gt;
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 For each pair of vertices (s,t), determine the fraction of shortest paths that pass through the vertex in question (here, vertex v).&lt;br /&gt;
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对于每对顶点(s，t) ，确定通过该顶点(这里是顶点 v)的最短路径的分数。&lt;br /&gt;
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# Sum this fraction over all pairs of vertices (''s'',''t'').&lt;br /&gt;
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 Sum this fraction over all pairs of vertices (s,t).&lt;br /&gt;
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对所有顶点对(s，t)求这个分数的和。&lt;br /&gt;
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More compactly the betweenness can be represented as:&amp;lt;ref name=&amp;quot;brandes&amp;quot;&amp;gt;{{cite journal |last1 = Brandes |first1 = Ulrik | year=2001 |title = A faster algorithm for betweenness centrality  | journal = Journal of Mathematical Sociology| volume=25|issue = 2 | pages=163–177| url = http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.11.2024 | accessdate = October 11, 2011| format = PDF | doi=10.1080/0022250x.2001.9990249|citeseerx = 10.1.1.11.2024 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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More compactly the betweenness can be represented as:&lt;br /&gt;
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更确切地说，两者之间的关系可以表示为:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
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{ math &amp;gt; c _ b (v) = sum _ { s neq v neq t in v } frac { sigma _ st }(v)}{ sigma _ st } &amp;lt;/math &amp;gt; &lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including ''v'', which for [[Digraph (mathematics)|directed graphs]] is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected [[Star (graph theory)|star graph]], the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including v, which for directed graphs is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected star graph, the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; sigma { st } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { st }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径数。有向图是 &amp;lt; math &amp;gt; (n-1)(n-2) &amp;lt;/math &amp;gt; ，无向图是 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; 。例如，在一个无向星图中，中心顶点(包含在每个可能的最短路径中)的中介性为 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; (1，如果标准化) ，而叶子(包含在没有最短路径中)的中介性为0。&lt;br /&gt;
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From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires [[Big O notation|&amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt;]] time with the [[Floyd–Warshall algorithm]]. However, on sparse graphs, [[Johnson's algorithm]] may be more efficient, taking [[Big O notation|&amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt;]] time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm&amp;lt;ref name=brandes/&amp;gt; which takes [[Big O notation|&amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt;]] time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&amp;lt;ref name=&amp;quot;brandes&amp;quot; /&amp;gt;&lt;br /&gt;
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From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires &amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt; time with the Floyd–Warshall algorithm. However, on sparse graphs, Johnson's algorithm may be more efficient, taking &amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt; time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm which takes &amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt; time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&lt;br /&gt;
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从计算的角度来看，图中所有顶点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介和紧密中心性Betweenness and Closeness centralities&amp;lt;/font&amp;gt;'''都涉及到计算图中所有顶点对之间的最短路径，这就需要用 Floyd-Warshall 算法计算时间。然而，对于稀疏图，约翰逊算法的效率可能更高，采用 &amp;lt; math &amp;gt; o (v ^ 2 log v + v e) &amp;lt;/math &amp;gt; 时间。在不加权图的情况下，可以用 Brandes 的算法进行计算，该算法需要 &amp;lt; math &amp;gt; o (v e) &amp;lt;/math &amp;gt; 时间。一般情况下，这些算法假定图是无向的，并且连通图中允许有圈和多条边。当专门处理网络图时，图通常没有环或多条边来维持简单的关系(其中的边表示两个人或顶点之间的联系)。在这种情况下，使用 Brandes 的算法将最终的中心性分数除以2来计算每条被重复计算的最短路径。&lt;br /&gt;
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==Eigenvector centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Eigenvector centrality}}&lt;br /&gt;
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'''Eigenvector centrality''' (also called '''eigencentrality''') is a measure of the influence of a [[node (networking)|node]] in a [[network (mathematics)|network]]. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&amp;lt;ref&amp;gt;{{cite journal|title = The mathematics of networks|url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf|author = M. E. J. Newman|accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;/&amp;gt; [[Google]]'s [[PageRank]] and the [[Katz centrality]] are variants of the eigenvector centrality.&amp;lt;ref name=&amp;quot;ams&amp;quot;&amp;gt;{{Cite web | url=http://www.ams.org/samplings/feature-column/fcarc-pagerank | title=American Mathematical Society}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Eigenvector centrality (also called eigencentrality) is a measure of the influence of a node in a network. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''(也称为特征中心性)是衡量网络中节点影响的一个指标。它将相对得分分配给网络中的所有节点，这是基于这样一个概念: 与得分较高的节点相比，与得分较低的节点相同的连接对所涉及的节点的得分贡献更大。&lt;br /&gt;
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=== Using the adjacency matrix to find eigenvector centrality ==&lt;br /&gt;
==使用'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''发现'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the [[adjacency matrix]], i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
&lt;br /&gt;
For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the adjacency matrix, i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
&lt;br /&gt;
对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 让 &amp;lt; math &amp;gt; a = (a { v，t }) &amp;lt;/math &amp;gt; 成为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''，即。如果顶点 &amp;lt; math &amp;gt; &amp;gt; v &amp;lt;/math &amp;gt; 与 math &amp;gt; t &amp;lt;/math &amp;gt; 相连，而 &amp;lt; math &amp;gt; a { v，t } = 0 &amp;lt;/math &amp;gt; 否则。顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分可以定义为:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
在 m (v)} x _ t = frac {1}{ lambda } sum { t in g } a { v，t } x _ t &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the [[eigenvector]] equation&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the eigenvector equation&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; m (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 和 &amp;lt; math &amp;gt; &amp;gt; lambda &amp;lt;/math &amp;gt; 的邻居集合。通过一个小的重新排列，这可以被重写成向量符号，作为特征向量方程&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[ math &amp;gt; mathbf { Ax } = { lambda } mathbf { x } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
In general, there will be many different [[eigenvalue]]s &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the [[Perron–Frobenius theorem]]. This greatest eigenvalue results in the desired centrality measure.&amp;lt;ref&amp;gt;{{cite journal  | author = M. E. J. Newman  | title = The mathematics of networks  | url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf  | accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt; The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices ''n''. [[Power iteration]] is one of many [[eigenvalue algorithm]]s that may be used to find this dominant eigenvector.&amp;lt;ref name=&amp;quot;ams&amp;quot; /&amp;gt; Furthermore, this can be generalized so that the entries in ''A'' can be real numbers representing connection strengths, as in a [[stochastic matrix]].&lt;br /&gt;
&lt;br /&gt;
In general, there will be many different eigenvalues &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the Perron–Frobenius theorem. This greatest eigenvalue results in the desired centrality measure. The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices n. Power iteration is one of many eigenvalue algorithms that may be used to find this dominant eigenvector. Furthermore, this can be generalized so that the entries in A can be real numbers representing connection strengths, as in a stochastic matrix.&lt;br /&gt;
&lt;br /&gt;
一般情况下，存在许多不同的特征值，对于这些特征值存在一个非零特征向量解。由于邻接矩阵中的条目是非负的，所以由 Perron-弗罗贝尼乌斯定理得出，它有一个实的和正的唯一最大特征值。由这个最大的特征值得出期望的中心性度量。相关特征向量的 &amp;lt; math &amp;gt; v ^ { th } &amp;lt;/math &amp;gt; 分量给出了网络中顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分。特征向量只定义了一个公共因子，所以只有顶点中心的比例是明确定义的。要定义一个绝对分数，必须对特征向量进行标准化，例如，使所有顶点的和为1或顶点的总数n。此外，这可以通用，使得 a 中的条目可以是表示连接强度的真实数字，就像'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 随机矩阵Stochastic matrix&amp;lt;/font&amp;gt;'''中一样。&lt;br /&gt;
&lt;br /&gt;
==Katz centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Katz centrality}}&lt;br /&gt;
&lt;br /&gt;
'''Katz centrality'''&amp;lt;ref&amp;gt;Katz, L. 1953. A New Status Index Derived from Sociometric Index. Psychometrika, 39–43.&amp;lt;/ref&amp;gt; is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
Katz centrality is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''是度中心性的推广。度中心性度量的是直接邻居的数量，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''度量的是通过一条路径可以连接的所有节点的数量，而远处节点的贡献会受到'''&amp;lt;font color=&amp;quot;#32CD32&amp;quot;&amp;gt; '削弱（惩罚？）Penalized&amp;lt;/font&amp;gt;''。在数学上，它被定义为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[数学][数学]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; (0,1) &amp;lt;/math &amp;gt; 中的衰减因子。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
&lt;br /&gt;
Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''可以看作是特征向量中心性的变体。Katz 中心性的另一种形式是&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
(x _ j + 1) &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
与特征向量中心性的表达式相比，&amp;lt; math &amp;gt; x _ j &amp;lt;/math &amp;gt; 被 &amp;lt; math &amp;gt; x _ j + 1所代替&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
It is shown that&amp;lt;ref&amp;gt;{{cite journal | last1 = Bonacich | first1 = P | year = 1991 | title = Simultaneous group and individual centralities | url = | journal = Social Networks | volume = 13 | issue = 2| pages = 155–168 | doi=10.1016/0378-8733(91)90018-o}}&amp;lt;/ref&amp;gt; the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
&lt;br /&gt;
It is shown that the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
&lt;br /&gt;
结果表明，主特征向量(与 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; ，邻接矩阵的最大特征值相关)是 Katz 中心性的极限，因为 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 接近 &amp;lt; math &amp;gt; tfrac {1}{ lambda } &amp;lt;/math &amp;gt; 。&lt;br /&gt;
&lt;br /&gt;
== PageRank centrality ==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页分布中心性PageRank&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
{{main|PageRank}}'''[[PageRank]]''' satisfies the following equation&lt;br /&gt;
&lt;br /&gt;
PageRank satisfies the following equation&lt;br /&gt;
&lt;br /&gt;
PageRank满足下面的等式&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1-alpha { n } ，&amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
其中&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[ math &amp;gt; l (j) = sum { i } a { ji } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&amp;lt;ref&amp;gt;[http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf How does Google rank webpages?] {{webarchive | url= https://web.archive.org/web/20120131083328/http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf |date=January 31, 2012 }} 20Q: About Networked Life&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&lt;br /&gt;
&lt;br /&gt;
是节点 &amp;lt; math &amp;gt; j &amp;lt;/math &amp;gt; (或有向图中出站链接的数量)的邻居数量。与特征向量中心性和 Katz 中心性相比，尺度因子 &amp;lt; math &amp;gt; l (j) &amp;lt;/math &amp;gt; 是一个主要的区别。PageRank 和特征向量中心性的另一个区别是 PageRank 向量是一个左手特征向量(注意因子 &amp;lt; math &amp;gt; a _ { ji } &amp;lt;/math &amp;gt; 具有相反的索引)。&lt;br /&gt;
&lt;br /&gt;
==Percolation centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&amp;lt;ref name=&amp;quot;piraveenan2013&amp;quot;&amp;gt;{{cite journal |last1 = Piraveenan |first1 = M. |last2 = Prokopenko |first2 = M.|last3 = Hossain|first3 = L. |year=2013| title = Percolation Centrality: Quantifying Graph-Theoretic Impact of Nodes during Percolation in Networks | journal = PLOS One | volume=8 | issue=1 | doi=10.1371/journal.pone.0053095 | pages=e53095 | pmid=23349699 | pmc=3551907| bibcode=2013PLoSO...853095P }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&lt;br /&gt;
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在复杂网络中，存在大量的中心性度量来确定单个节点的“重要性”。然而，这些度量单纯从拓扑学的角度来量化节点的重要性，节点的值并不以任何方式依赖于节点的状态。不管网络动态如何，它都保持不变。即使对于加权的两者之间的度量也是如此。然而，一个节点可能很好地位于'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''或其他中心性度量的中心位置，但可能不是位于有过滤的网络的上下文中的中心位置。在许多情况下，复杂网络中都会出现“传染”现象。例如，病毒或细菌感染可以通过人们的社交网络传播，也就是所谓的接触网络。还可以在更高的抽象层次上考虑疾病的传播问题，设想通过公路、铁路或空中连接起来的城镇或人口中心网络。计算机病毒可以通过计算机网络传播。关于商业活动和交易的谣言或新闻也可以通过人们的社交网络传播。在所有这些情况下，一种“传染病”在一个复杂网络的链接上传播，随着它的传播，无论是可恢复的还是不可恢复的，都会改变节点的“状态”。例如，在流行病学方案中，随着感染扩散，个人从”易感”状态转变为”受感染”状态。在上面的例子中，随着传染的扩散，每个节点可以采取的状态可以是二进制的(例如接收/没有接收到一条新闻)、离散的(易感/受感染/康复) ，甚至是连续的(例如一个城镇中受感染的人的比例) 。这些情景的共同特点是，传染的扩散导致网络中节点状态的改变。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''（PC)就是基于这个思想而提出的，它特别地衡量了节点在协助网络渗滤方面的重要性。这项措施是由 piraveanan 等人提出的。&lt;br /&gt;
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'''Percolation centrality''' is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
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Percolation centrality is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''定义为在给定时间内一个给定节点的过滤路径的比例。“渗滤路径”是一对节点之间的最短路径，其中源节点被渗滤(例如，被感染)。目标节点可以是过滤的或非过滤的，或处于部分过滤状态。&lt;br /&gt;
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:&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; PC ^ t (v) = frac {1}{ N-2} sum { s neq v neq r } frac { sigma { sr }(v)}{ sigma { sr }} frac { x ^ t }{ sum {[{ x ^ t } i }}}]}}-{ x ^ t }{ v } &amp;lt;/math &amp;gt; &lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; σ { sr } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; r &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { sr }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径的总数。在时间 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 时，节点的过滤状态用 &amp;lt; math &amp;gt; { x ^ t } _ i &amp;lt;/math &amp;gt; 表示，两个特殊情况是当 &amp;lt; math &amp;gt; { x ^ t } _ i = 0 &amp;lt;/math &amp;gt; 表示在时间上是非过滤状态，而当 &amp;lt; math &amp;gt; &amp;lt; x ^ t &amp;lt;/math &amp;gt; i = 1 &amp;lt;/math &amp;gt; 表示在时间上是完全过滤状态。两者之间的值表示部分过滤状态(例如，在一个城镇网络中，这是该城镇感染者的百分比)。&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in [[Big O notation|&amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt;]] time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is [[Big O notation|&amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;]].&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in &amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt; time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is &amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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渗流路径的权重取决于分配给源节点的渗流水平，前提是源节点的渗流水平越高，源节点的路径就越重要。因此，位于源自高渗滤节点的最短路径上的节点可能对渗滤更为重要。PC 的定义也可以扩展到包括目标节点的权重。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''计算运行在 &amp;lt; math &amp;gt; o (NM) &amp;lt;/math &amp;gt; 时间，采用了 Brandes 快速算法的有效实现，如果计算需要考虑目标节点的权重，最坏情况下时间为 &amp;lt; math &amp;gt; o (n ^ 3) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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==Cross-clique centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 交叉团中心性Cross-clique centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
'''Cross-clique centrality''' of a single node in a complex graph determines the connectivity of a node to different [[clique (graph theory)|clique]]s. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in &amp;lt;ref name=&amp;quot;xssworms&amp;quot;&amp;gt;{{cite journal |last1 = Faghani|first1 = Mohamamd Reza| year=2013| title = A Study of XSS Worm Propagation and Detection Mechanisms in Online Social Networks | journal = IEEE Transactions on Information Forensics and Security|volume = 8|issue = 11|pages = 1815–1826|doi = 10.1109/TIFS.2013.2280884}}&amp;lt;/ref&amp;gt; but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
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Cross-clique centrality of a single node in a complex graph determines the connectivity of a node to different cliques. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in  but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
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复杂图中单个节点的跨团中心性决定了一个节点与不同团的连通性。具有高度跨团连通性的节点有利于信息或疾病在图中的传播。团是一种'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图Subgraphs&amp;lt;/font&amp;gt;'''，团中的每个节点都与团中的其他节点相连。对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边的交叉团连通性，定义为 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; x (v) &amp;lt;/math &amp;gt; 其中 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 所属的顶点团数。这个测度应用日久，但是在1998年由 Everett 和 Borgatti 首次提出，他们称之为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 派系重叠中心性Clique-overlap centrality&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Freeman centralization==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心度Freeman centralization&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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The '''centralization''' of any network is a measure of how central its most central node is in relation to how central all the other nodes are.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;&amp;gt;{{citation | journal = Social Networks | last1 = Freeman | first1 = Linton C. | year = 1979 | volume = 1 | issue = 3 | pages = 215–239 | title = centrality in social networks: Conceptual clarification | url = http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | doi = 10.1016/0378-8733(78)90021-7 | citeseerx = 10.1.1.227.9549 | access-date = 2014-07-31 | archive-url = https://web.archive.org/web/20160222033108/http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | archive-date = 2016-02-22 | url-status = dead }}&amp;lt;/ref&amp;gt; Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
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The centralization of any network is a measure of how central its most central node is in relation to how central all the other nodes are. Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
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任何网络的集中度都是衡量其最核心的节点相对于其他所有节点的集聚程度的标准。集中度的度量方法是: (a)计算网络中最中心的节点与所有其他节点之间的中心性差异之和; (b)将这个数量除以理论上相同规模的任何网络中这种差异之和的最大值。因此，每个中心性度量都可以有自己的集中性度量。正式定义，如果 &amp;lt; math &amp;gt; c _ x (p _ i) &amp;lt;/math &amp;gt; 是点 &amp;lt; math &amp;gt; i &amp;lt;/math &amp;gt; 的中心性度量，如果 &amp;lt; math &amp;gt; c _ x (p _ *) &amp;lt;/math &amp;gt; 是网络中最大的中心性度量，如果:&lt;br /&gt;
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:&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; max sum { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i) &amp;lt;/math &amp;gt; &lt;br /&gt;
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is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;&lt;br /&gt;
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is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&lt;br /&gt;
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对于任何具有相同节点数的图来说，点中心性的最大差异是:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; c _ x = frac { sum _ { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i)}{ max sum _ { i = 1 ^ { n } c _ x (p _ *)-c _ x (p _ i)} . &amp;lt;/math &amp;gt;&lt;br /&gt;
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== Dissimilarity based centrality measures ==&lt;br /&gt;
==基于相异性的中心性度量==&lt;br /&gt;
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[[File:Srep17095-f1.jpg|thumbnail|In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.]]&lt;br /&gt;
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In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.&lt;br /&gt;
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在图示的网络中，绿色节点和红色节点最不相似，因为它们之间不共享相邻节点。因此，绿色的节点比灰色的节点对中心性的贡献更大，因为红色的节点只能通过绿色访问蓝色的节点，而灰色的节点对于红色的节点是多余的，因为它可以直接访问每个灰色的节点，而不需要任何中介。&lt;br /&gt;
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In order to obtain better results in the ranking of the nodes of a given network,  in &amp;lt;ref&amp;gt;{{Cite journal|title = Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|journal = Scientific Reports|date = 2015-11-25|pmc = 4658528|pmid = 26603652|volume = 5|doi = 10.1038/srep17095|first = A. J.|last = Alvarez-Socorro|first2 = G. C.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz|pages=17095|bibcode = 2015NatSR...517095A}}&amp;lt;/ref&amp;gt; are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with [[eigenvector centrality]], calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
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In order to obtain better results in the ranking of the nodes of a given network,  in  are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with eigenvector centrality, calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
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为了在给定网络节点的排序中获得更好的结果，在复杂网络中使用了相异性度量(特定于分类和数据挖掘理论)来丰富中心性度量。特征向量中心性通过求解特征值问题来计算每个节点的中心性&lt;br /&gt;
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:&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
数学，数学&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary [[Matrix similarity|dissimilarity]] matrix, defined through a dissimilitary measure, e.g., [[Jaccard index|Jaccard]] dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary dissimilarity matrix, defined through a dissimilitary measure, e.g., Jaccard dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
这里 &amp;lt; math &amp;gt; w { ij } = a { ij } d { ij } &amp;lt;/math &amp;gt; (coordinate-to-coordinate product)和 &amp;lt; math &amp;gt; d { ij } &amp;lt;/math &amp;gt; 是一个任意的不相似矩阵，通过一个双重军事度量来定义，例如，Jaccard 由&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1-dfrac { | v ^ { + }(i) cap v ^ { + }(j) | }{ | v ^ { + }(i) cup v ^ { + }(j) | } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
&lt;br /&gt;
Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
&lt;br /&gt;
这种度量允许我们量化每个节点对给定节点中心性的拓扑贡献(这就是为什么我们称之为贡献中心性) ，对那些相异性较大的节点有更多的权重/相关性，因为这些节点允许给定的节点访问那些它们自己不能直接访问的节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the [[Perron–Frobenius theorem]] to ensure that the above problem has a unique solution for ''λ'' = ''λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt;'' with '''c''' non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
&lt;br /&gt;
Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the Perron–Frobenius theorem to ensure that the above problem has a unique solution for λ = λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt; with c non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
&lt;br /&gt;
值得注意的是，&amp;lt; math &amp;gt; w &amp;lt;/math &amp;gt; 是非负的，因为 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; d &amp;lt;/math &amp;gt; 都是非负矩阵，所以我们可以使用 Perron 弗罗贝尼乌斯定理来确保上述问题对于 c 非负的 = &amp;lt; sub &amp;gt; max &amp;lt;/sub &amp;gt; 有唯一的解，这样我们就可以推断出网络中每个节点的中心性。因此，i-th 节点的中心性为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1{ n } sum { j = 1} ^ { n } w { ij } c { j } ，，，，，j = 1，cdots，n &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in &amp;lt;ref&amp;gt;{{Cite web|url = http://www.nature.com/article-assets/npg/srep/2015/151125/srep17095/extref/srep17095-s1.pdf|title = Supplementary Information for Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|date = |website = |publisher = Nature Publishing Group|last = Alvarez-Socorro|first = A.J.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz}}&amp;lt;/ref&amp;gt; obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in  obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是网络中的节点数。几个不同的措施和网络进行了测试，以获得在研究案例的改善的结果。&lt;br /&gt;
&lt;br /&gt;
==Extensions==&lt;br /&gt;
==扩展==&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality&amp;lt;ref&amp;gt;{{cite journal | last1 = Braha | first1 = D. | last2 = Bar-Yam | first2 = Y. | year = 2006 | title = From Centrality to Temporary Fame: Dynamic Centrality in Complex Networks | url = | journal = Complexity | volume = 12 | issue = 2| pages = 59–63 | doi=10.1002/cplx.20156| arxiv = physics/0611295 | bibcode = 2006Cmplx..12b..59B }}&amp;lt;/ref&amp;gt; in the context of time-dependent and temporal networks.&amp;lt;ref&amp;gt;{{cite journal | last1 = Hill | first1 = S.A. | last2 = Braha | first2 = D. | year = 2010 | title = Dynamic Model of Time-Dependent Complex Networks | url = | journal = Physical Review E | volume = 82 | issue = 4| page = 046105 | doi=10.1103/physreve.82.046105| pmid = 21230343 | arxiv = 0901.4407 | bibcode = 2010PhRvE..82d6105H }}&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Gross, T. and Sayama, H. (Eds.). 2009. ''Adaptive Networks: Theory, Models and Applications.'' Springer.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Holme, P. and Saramäki, J. 2013. ''Temporal Networks.'' Springer.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality in the context of time-dependent and temporal networks.&lt;br /&gt;
&lt;br /&gt;
经验和理论研究已经将静态网络中的中心性概念扩展到时间依赖网络和时间网络中的动态中心性。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&amp;lt;ref&amp;gt;{{cite journal | last1 = Opsahl | first1 = Tore | last2 = Agneessens | first2 = Filip | last3 = Skvoretz | first3 = John | title = Node centrality in weighted networks: Generalizing degree and shortest paths | doi = 10.1016/j.socnet.2010.03.006 | year = 2010 | pages = 245–251 | volume = 32 | journal = Social Networks | url = http://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | issue = 3 | access-date = 2010-04-23 | archive-url = https://web.archive.org/web/20180226080331/https://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | archive-date = 2018-02-26 | url-status = dead }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&lt;br /&gt;
&lt;br /&gt;
对加权网络的推广，见 Opsahl 等人。(2010).&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, '''group betweenness''' centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&amp;lt;ref name=&amp;quot;group1&amp;quot;&amp;gt;Everett, M. G. and Borgatti, S. P. (2005). Extending centrality. In P. J. Carrington, J. Scott and S. Wasserman (Eds.), ''Models and methods in social network analysis'' (pp. 57–76). New York: Cambridge University Press.&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;group2&amp;quot;&amp;gt;Puzis, R., Yagil, D., Elovici, Y., Braha, D. (2009).[http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf Collaborative attack on Internet users’ anonymity] {{Webarchive|url=https://web.archive.org/web/20131207133417/http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf |date=2013-12-07 }}, ''Internet Research'' '''19'''(1)&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, group betweenness centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&lt;br /&gt;
&lt;br /&gt;
中心性的概念也扩展到了群体层次。例如，组间的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''显示了连接穿过组的成对非组成员的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Geodesics &amp;lt;/font&amp;gt;'''的比例。&lt;br /&gt;
&lt;br /&gt;
==See also==&lt;br /&gt;
==又及==&lt;br /&gt;
* [[Alpha centrality]]&lt;br /&gt;
&lt;br /&gt;
* [[Core–periphery structure]]&lt;br /&gt;
&lt;br /&gt;
* [[Distance (graph theory)|Distance in graphs]]&lt;br /&gt;
&lt;br /&gt;
*阿尔法中心性&lt;br /&gt;
&lt;br /&gt;
*核心—外围结构&lt;br /&gt;
&lt;br /&gt;
*距离（图理论）图中的距离&lt;br /&gt;
&lt;br /&gt;
==Notes and references==&lt;br /&gt;
&lt;br /&gt;
{{Reflist}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Further reading==&lt;br /&gt;
拓展阅读&lt;br /&gt;
* Koschützki, D.; Lehmann, K. A.; Peeters, L.; Richter, S.; Tenfelde-Podehl, D. and Zlotowski, O. (2005) Centrality Indices. In Brandes, U. and Erlebach, T. (Eds.)  ''Network Analysis: Methodological Foundations'', pp.&amp;amp;nbsp;16–61, LNCS 3418, Springer-Verlag.&lt;br /&gt;
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[[Category:Graph theory]]&lt;br /&gt;
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Category:Graph theory&lt;br /&gt;
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分类: 图论&lt;br /&gt;
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[[Category:Graph algorithms]]&lt;br /&gt;
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Category:Graph algorithms&lt;br /&gt;
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分类: 图形算法&lt;br /&gt;
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[[Category:Algebraic graph theory]]&lt;br /&gt;
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Category:Algebraic graph theory&lt;br /&gt;
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分类: 代数图论&lt;br /&gt;
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[[Category:Networks]]&lt;br /&gt;
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Category:Networks&lt;br /&gt;
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分类: 网络&lt;br /&gt;
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[[Category:Network analysis]]&lt;br /&gt;
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Category:Network analysis&lt;br /&gt;
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分类: 网络分析&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Centrality]]. Its edit history can be viewed at [[网络中心性/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E7%BD%91%E7%BB%9C%E4%B8%AD%E5%BF%83%E6%80%A7&amp;diff=19673</id>
		<title>网络中心性</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E7%BD%91%E7%BB%9C%E4%B8%AD%E5%BF%83%E6%80%A7&amp;diff=19673"/>
		<updated>2020-12-05T02:59:16Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;此词条暂由水流心不竞初译，未经审校，带来阅读不便，请见谅。&lt;br /&gt;
&lt;br /&gt;
{{for|the statistical concept|Central tendency}}&lt;br /&gt;
{{Network Science}}&lt;br /&gt;
&lt;br /&gt;
In [[graph theory]] and [[network theory|network analysis]], indicators of '''centrality''' identify the most important [[vertex (graph theory)|vertices]] within a graph. Applications include identifying the most influential person(s) in a [[social network]], key infrastructure nodes in the [[Internet]] or [[urban network]]s, and [[super-spreader]]s of disease. Centrality concepts were first developed in [[social network analysis]], and many of the terms used to measure centrality reflect their [[sociology|sociological]] origin.&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;&lt;br /&gt;
In graph theory and network analysis, indicators of centrality identify the most important vertices within a graph. Applications include identifying the most influential person(s) in a social network, key infrastructure nodes in the Internet or urban networks, and super-spreaders of disease. Centrality concepts were first developed in , and many of the terms used to measure centrality reflect their sociological origin.&lt;br /&gt;
&lt;br /&gt;
They should not be confused with [[node influence metric]]s, which seek to quantify the influence of every node in the network.&lt;br /&gt;
They should not be confused with node influence metrics, which seek to quantify the influence of every node in the network.&lt;br /&gt;
&lt;br /&gt;
在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;图论 graph theory &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络分析 network analysis &amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性 centrality &amp;lt;/font&amp;gt;'''指标用于识别图中最重要的顶点。其应用包括在社会网络中识别出最有影响力的个人，在因特网或城市网络中识别出最为关键的基础设施节点，以及识别疾病的超级传播者。中心性的概念最初由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;社会网络分析 social network analysis&amp;lt;/font&amp;gt;'''所发展，因此许多用于衡量中心性的术语都反映出了它们的社会学出身。中心性不应与节点影响度相混淆，后者意在量化网络中每个节点的影响。&lt;br /&gt;
&lt;br /&gt;
==中心性指数的定义与特性Definition and characterization of centrality indices==&lt;br /&gt;
&lt;br /&gt;
Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|title = Eigenvector centrality for characterization of protein allosteric pathways|journal = Proceedings of the National Academy of Sciences|volume = 115|number = 52|pages = E12201–E12208|year = 2018|doi = 10.1073/pnas.1810452115|pmid = 30530700|pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性指数Centrality indices &amp;lt;/font&amp;gt;'''是对“重要顶点的特征是什么”这一问题的回答，答案以图顶点的实值函数的方式给出，在这些顶点上的取值的排序标识出最重要的节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
&lt;br /&gt;
The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
&lt;br /&gt;
“重要性”这个词有许多含义，导致了许多不同的中心性定义。分为两类。&lt;br /&gt;
&lt;br /&gt;
&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important.&amp;lt;ref name=Borgatti2005/&amp;gt; &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt; Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important. Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&lt;br /&gt;
&lt;br /&gt;
“重要性”可以被认为与一种跨网络的流动或传输有关。这允许根据它们认为重要的流类型对中心性进行分类。这两种方法都将中心性划分为不同的类别。进一步的推论是，适用于一个类别的中心性在（推广）应用于另一个类别时往往会“出错”。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one ([[Centrality#Degree centrality|degree centrality]]) to infinite walks ([[Centrality#Eigenvector centrality|eigenvalue centrality]]).&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=&amp;quot;Benzi2013&amp;quot;&amp;gt;{{cite journal | last1=Benzi | first1=Michele | last2=Klymko| first2=Christine | year=2013 |title= A matrix analysis of different centrality measures |arxiv=1312.6722 | doi=10.1137/130950550 | volume=36 | issue=2 | journal=SIAM Journal on Matrix Analysis and Applications | pages=686–706}}&amp;lt;/ref&amp;gt; The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
&lt;br /&gt;
When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one (degree centrality) to infinite walks (eigenvalue centrality). The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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当中心性按照它们对'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 内聚性Cohesiveness&amp;lt;/font&amp;gt;'''的趋近程度来分类时，很明显，大多数中心性都集中在一个类别中。从一个给定顶点开始对步数计数，不同之处只在于行走的定义和计数方式。对该组描述的约束限制，从位置中心（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心度Degree centrality&amp;lt;/font&amp;gt;'''）到单元域（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征中心度Eigenvalue centrality&amp;lt;/font&amp;gt;'''），观察到许多中心性都有这种相似关系，这也许可以解释这些指数之间的高阶相关性。&lt;br /&gt;
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===Characterization by network flows==&lt;br /&gt;
==网络流特征==&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at once.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at oe.&lt;br /&gt;
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一个网络可以被看成是对某种物体流动的路径描述。使基于流的类型和由中心性编码的路径类型（同时）得到表征。一个流可以基于传输，每个不可分割的项目从一个节点到另一个节点，就像一个包裹从配送站送到客户的房子。第二种情况是串行复制，在这种情况下，一个项从源节点被复制到达目标节点。例如通过流言传播信息，以私有方式传播信息，并在流程结束时通知源节点和目标节点。最后一种情况是并行复制，即同时将项目复制到多个链接，就像无线电广播一次性向多个听众提供相同的信息。&lt;br /&gt;
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Likewise, the type of path can be constrained to [[Distance (graph theory)|geodesics]] (shortest paths), [[Glossary of graph theory terms#path|paths]]  (no vertex is visited more than once), [[Glossary of graph theory terms#trail|trails]] (vertices can be visited multiple times, no edge is traversed more than once), or [[Glossary of graph theory terms#walk|walks]] (vertices and edges can be visited/traversed multiple times).&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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Likewise, the type of path can be constrained to geodesics (shortest paths), paths  (no vertex is visited more than once), trails (vertices can be visited multiple times, no edge is traversed more than once), or walks (vertices and edges can be visited/traversed multiple times).&lt;br /&gt;
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同样，路径类型可以被限定为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Distance &amp;lt;/font&amp;gt;'''(最短路径)、路径(对顶点的访问不超过一次)、小径(可以访问多次顶点，没有边被访问超过一次)或者步子(可以访问/遍历多次顶点和边)。&lt;br /&gt;
===Characterization by walk structure===&lt;br /&gt;
==行走结构特征==&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either ''radial'' or ''medial.'' Radial centralities count walks which start/end from the given vertex. The [[Centrality#Degree centrality|degree]] and [[Centrality#Eigenvector centrality|eigenvalue]] centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's [[Centrality#Betweenness centrality|betweenness]] centrality, the number of shortest paths which pass through the given vertex.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either radial or medial. Radial centralities count walks which start/end from the given vertex. The degree and eigenvalue centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's betweenness centrality, the number of shortest paths which pass through the given vertex.&lt;br /&gt;
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可以从中心性的构造方式推导出另一种分类方法。这又分成了两个类。中心点可以是放射状的，也可以是内侧的。从给定顶点开始/结束的径向中心点数。度和特征值中心是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 径向中心Radial centralities&amp;lt;/font&amp;gt;'''的例子，计算长度为一或无穷大的行走的个数。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中间中心性Medial centralities&amp;lt;/font&amp;gt;'''计算通过给定顶点的步数。典型的例子是 弗里曼的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality,&amp;lt;/font&amp;gt;'''，即穿过给定顶点的最短路径的数量。&lt;br /&gt;
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Likewise, the counting can capture either the ''volume'' or the ''length'' of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's [[Centrality#Closeness centrality|closeness]] centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example.&amp;lt;ref name=Borgatti2006/&amp;gt; Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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Likewise, the counting can capture either the volume or the length of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's closeness centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example. Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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同样地，计数可以抓住行走的体积或长度。体积是给定类型的行走的总数。上一段的三个例子就属于这一类。长度则给出从给定顶点到图中其余顶点的距离。弗里曼 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，即从一个给定顶点到所有其他顶点的测地距离，是最著名的例子。请注意，这种分类独立于步行计数的类型(即：步行，小道，路径，测地线)。&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&lt;br /&gt;
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博尔加蒂和埃弗雷特提出，这种类型学为如何最好地比较中心性度量提出了建议。在这个22分类中，放在同一盒子中的中心点足够相似，可以做出合理的选择; 人们可以合理地比较哪个对于给定的应用更好。然而，不同盒子中的度量方法是截然不同的。只有在预先确定哪个类别更适用的情况下，对相对适应性的评估才会发生，这使得比较变得毫无意义。&lt;br /&gt;
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===Radial-volume centralities exist on a spectrum===&lt;br /&gt;
==光谱上存在的径向体积中心==&lt;br /&gt;
The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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步行结构的特征表明，几乎所有广泛使用的中心性都是径向体积的衡量。这得出结论顶点的中心性是与之相关联的顶点中心性的函数。中心性根据如何定义关联而不同。&lt;br /&gt;
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Bonacich showed that if association is defined in terms of [[Glossary of graph theory terms#walk|walks]], then a family of centralities can be defined based on the length of walk considered.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;/&amp;gt; [[Centrality#Degree centrality|Degree centrality]] counts walks of length one, while [[Centrality#Eigenvector centrality|eigenvalue centrality]] counts walks of length infinity. Alternative definitions of association are also reasonable. [[Alpha centrality]] allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich showed that if association is defined in terms of walks, then a family of centralities can be defined based on the length of walk considered. Degree centrality counts walks of length one, while eigenvalue centrality counts walks of length infinity. Alternative definitions of association are also reasonable. Alpha centrality allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich 指出，如果联想是根据行走来定义的，那么可以根据考虑的行走长度来定义一个中心性家族。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''计算长度为1的行走，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征值中心性Eigenvalue centrality  &amp;lt;/font&amp;gt;'''计算长度为无穷大的行走。关联的其他定义也是合理的。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 阿尔法中心性Alpha centrality&amp;lt;/font&amp;gt;'''允许顶点有一个外部影响源。埃斯特拉达的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图中心性Subgraph centrality &amp;lt;/font&amp;gt;'''提出只计算封闭路径(三角形、正方形等)。).&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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这些测量方法的核心是这种现象：图中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵&amp;lt;/font&amp;gt;'''的幂给出了由该幂给出的散步长度的数目。同样，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 矩阵指数Matrix exponential&amp;lt;/font&amp;gt;'''也与给定长度的行走次数密切相关。邻接矩阵的初始转换允许对步行计数的类型进行不同的定义。无论采用哪种方法，顶点的中心性都可以表示为无穷和&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum _ { k = 0} ^ infty a _ { r } ^ { k } beta ^ k &amp;lt;/math &amp;gt; &lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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矩阵能量或者&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum { k = 0} ^ infty frac {(a _ r beta) ^ k }{ k！{/math &amp;gt; &lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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对于矩阵指数函数，其中&lt;br /&gt;
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* &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; is walk length,&lt;br /&gt;
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* &amp;lt;math&amp;gt;A_R&amp;lt;/math&amp;gt; is the transformed adjacency matrix, and&lt;br /&gt;
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* &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; is a discount parameter which ensures convergence of the sum.&lt;br /&gt;
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K为步长，A_R是邻接矩阵的转秩，贝达是保证收敛的折扣参数。&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. [[Alpha centrality]] replaces the adjacency matrix with its [[resolvent formalism|resolvent]]. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to [[Centrality#Degree centrality|degree centrality]]. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to [[Centrality#Eigenvector centrality|eigenvalue centrality]].&amp;lt;ref name=Benzi2013/&amp;gt;&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. Alpha centrality replaces the adjacency matrix with its resolvent. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to degree centrality. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to eigenvalue centrality.&lt;br /&gt;
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博纳奇的一系列措施并没有改变邻接矩阵。阿尔法集中性用它的解决方案替代了邻接矩阵。子图集中性用它的踪迹取代了邻接矩阵。一个令人吃惊的结论是，不管邻接矩阵最初的转变是什么，所有这些方法都有共同的限制行为。随着贝塔系数趋近于零，指数收敛到度中心性。随着贝塔系数接近其最大值，指数收敛到特征值的中心性。&lt;br /&gt;
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===Game-theoretic centrality===&lt;br /&gt;
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=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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上述大多数标准措施的共同特点是，它们通过只关注一个节点本身所扮演的角色来评估确定节点的重要性。然而, 在许多应用中，这种方法是不充分的，因为可能会发生协同作用&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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如果将节点的功能分组考虑。&lt;br /&gt;
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[[File:Game-theoretic centrality.png|Example of game-theoretic centrality]]&lt;br /&gt;
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Example of game-theoretic centrality&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''的例子&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in &amp;lt;ref&amp;gt;Michalak, Aadithya, Szczepański, Ravindran, &amp;amp; Jennings {{ArXiv|1402.0567}}&amp;lt;/ref&amp;gt; uses the [[Shapley value]]. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
&lt;br /&gt;
For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in  uses the Shapley value. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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例如，考虑阻止流行病的问题。看看上面的网络图像，我们应该给哪些节点接种疫苗？基于前面描述的措施，我们希望识别在疾病传播中最重要的节点。仅仅基于中心的方法，即关注节点的个别特性，可能不是一个好主意。红色方块中的节点，单独不能阻止疾病的传播，但把它们作为一个群体来考虑，我们清楚地看到，如果疾病在节点 &amp;lt; math &amp;gt; v _ 1 &amp;lt;/math &amp;gt; 、 &amp;lt; math &amp;gt; v _ 4 &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; v _ 5 &amp;lt;/math &amp;gt; 中开始，它们就能阻止疾病的传播。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''试图利用博弈论中的工具来研究所描述的问题和机会。本文提出的方法使用了 Shapley 值。由于 Shapley 值计算的时间复杂性，这一领域的大部分工作都集中在实现新的算法和方法，这些算法和方法依赖于网络的特殊拓扑结构或问题的特殊性质。这种方法可以将时间复杂度从指数级降低到多项式级。&lt;br /&gt;
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Similarly, the solution concept [[authority distribution]] (&amp;lt;ref&amp;gt;{{cite journal |last=Hu |first=Xingwei |first2=Lloyd |last2=Shapley |title=On Authority Distributions in Organizations |journal=Games and Economic Behavior |volume=45 |pages=132–170 |year=2003 | doi = 10.1016/s0899-8256(03)00130-1 }}&amp;lt;/ref&amp;gt;) applies the [[Shapley-Shubik power index]], rather than the [[Shapley value]], to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020)&amp;lt;ref&amp;gt;{{cite journal|last=Hu|first=Xingwei|year=2020|volume=7|title=Sorting big data by revealed preference with application to college ranking |journal=Journal of Big Data|doi=10.1186/s40537-020-00300-1|doi-access=free}}&amp;lt;/ref&amp;gt;, such as ranking U.S. colleges.&lt;br /&gt;
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Similarly, the solution concept authority distribution () applies the Shapley-Shubik power index, rather than the Shapley value, to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020), such as ranking U.S. colleges.&lt;br /&gt;
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同样，'''&amp;lt;font color=&amp;quot;#CD32CD&amp;quot;&amp;gt; 加权分布概念的解()The solution concept authority distribution () &amp;lt;/font&amp;gt;'''采用 Shapley-Shubik 幂指数，而不是 Shapley 值来衡量双方之间的直接影响。这种分布确实是一种产生'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征向量中心性Engenvector centrality&amp;lt;/font&amp;gt;'''的类型。它用于对 Hu (2020)中的大数据对象进行排序，比如美国大学排名。&lt;br /&gt;
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== Important limitations ==&lt;br /&gt;
==重要限制==&lt;br /&gt;
Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the [[Krackhardt kite graph]], for which three different notions of centrality give three different choices of the most central vertex.&amp;lt;ref&amp;gt;{{cite journal|title=Assessing the Political Landscape: Structure, Cognition, and Power in Organizations|first=David|last=Krackhardt|authorlink=David Krackhardt|journal=Administrative Science Quarterly|volume=35|issue=2|date=June 1990|pages=342–369|doi=10.2307/2393394|jstor=2393394}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the Krackhardt kite graph, for which three different notions of centrality give three different choices of the most central vertex.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中心性Centrality&amp;lt;/font&amp;gt;'''指标有两个重要的局限性，一个显而易见，另一个则不易察觉。显而易见的局限性是，对于一个应用最优的中心性对于另一个应用常常是次优的。事实上，如果不是这样，我们就不需要这么多不同的中心性。克拉克哈特风筝图为这一现象提供了一个例证，对于这个图，三个不同的中心性概念给出了三个最中心顶点的不同选择。&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices.&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=Borgatti2005/&amp;gt; This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  [[node influence metric]]s to address this problem.&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices. This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  node influence metrics to address this problem.&lt;br /&gt;
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更不易察觉的限制是通常会错误地认为顶点中心性表示顶点的相对重要性。中心性指数被明确地设计来产生一个指出最重要顶点的排名。在刚才提到的限制下，他们做得很好。它们通常不用来测量节点的影响力。最近，网络物理学家开始开发'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;节点影响度量Node influence metrics &amp;lt;/font&amp;gt;'''来解决这个问题。&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying [[Centrality#Freeman centralization|Freeman centralization]] to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt; This approach, however, is seldom seen in practice.{{citation needed|reason=I've come across quite some theoretical studies that indicate otherwise. My suggestion is to remove this sentence, if reasonable citation is not provided.|date=September 2015}}&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying Freeman centralization to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores. This approach, however, is seldom seen in practice.&lt;br /&gt;
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错误有两方面。首先，一个排名只根据顶点的重要性排序，它并不对节点重要性的不同水平进行量化区分。这可以通过将 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;'''应用到中心性度量来缓解，这种度量可以根据节点的不同中心性得分来判断节点的重要性。此外， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;''使人们能够通过比较几个网络的最高中心性得分来比较它们。然而，这种方法在实践中很少见到。&lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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其次，用以(正确地)识别给定网络/应用中最重要顶点的特征并不一定可推广到其余顶点。&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot; /&amp;gt;&amp;lt;ref name=&amp;quot;daSilva2012&amp;quot;&amp;gt;{{cite journal | last1=da Silva|first1=Renato |last2=Viana|first2=Matheus|last3=da F. Costa |first3=Luciano| title=Predicting epidemic outbreak from individual features of the spreaders| journal=J. Stat. Mech.: Theory Exp. | year=2012|volume=2012|pages=P07005|number=7 | doi=10.1088/1742-5468/2012/07/p07005|arxiv=1202.0024|bibcode=2012JSMTE..07..005A}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Bauer2012&amp;quot;&amp;gt;{{cite journal | last1=Bauer|first1=Frank | last2=Lizier|first2=Joseph|title=Identifying influential spreaders and efficiently estimating infection numbers in epidemic models: A walk counting approach| journal=Europhys Lett | year=2012| volume=99| pages=68007|number=6 | doi=10.1209/0295-5075/99/68007|arxiv=1203.0502|bibcode=2012EL.....9968007B}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Sikic2013&amp;quot;&amp;gt;{{ cite journal| last1= Sikic| first1=Mile|last2=Lancic|first2=Alen|last3=Antulov-Fantulin|first3=Nino|last4=Stefanic|first4=Hrvoje| title = Epidemic centrality -- is there an underestimated epidemic impact of network peripheral nodes? |journal = The European Physical Journal B |volume=86 |number=10 |pages=1–13 |year=2013 | doi=10.1140/epjb/e2013-31025-5|arxiv=1110.2558 | bibcode=2013EPJB...86..440S}}&amp;lt;/ref&amp;gt; This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&amp;lt;ref name=&amp;quot;Ghoshal2011&amp;quot;&amp;gt;{{cite journal | last1=Ghoshal | first1= G. | last2= Barabsi |first2= A L | title = Ranking stability and super-stable nodes in complex networks. | journal = Nat Commun | volume =2 | page = 394| year= 2011 | doi=10.1038/ncomms1396 | pmid= 21772265 | bibcode=2011NatCo...2..394G | doi-access= free }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless. This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&lt;br /&gt;
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对于大多数其他网络节点，排名可能是没有意义的。这就解释了为什么，例如，只有谷歌图片搜索的前几个结果以合理的顺序出现。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页排名Pagerank&amp;lt;/font&amp;gt;'''是一个非常不稳定的度量，显示了在跳转参数小的调整之后频繁的秩逆转。&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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虽然中心性指数未能推广到网络的其他部分，乍看起来似乎是违反直觉的，但它直接遵循上述定义。&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot;&amp;gt;{{cite journal |last1= Lawyer |first1= Glenn |year= 2015 |title= Understanding the spreading power of all nodes in a network: a continuous-time perspective |journal=Sci Rep |volume=5|pages=8665|doi=10.1038/srep08665 |pmid=25727453 |pmc=4345333|arxiv=1405.6707|bibcode=2015NatSR...5E8665L}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&lt;br /&gt;
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复杂网络具有异构的拓扑结构。由于最佳度量取决于最重要顶点的网络结构，对于这些顶点最优的度量对于网络的其余部分是次优的。&lt;br /&gt;
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==Degree centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Degree (graph theory)}} &lt;br /&gt;
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[[File:6 centrality measures.png|thumb|right|300px|Examples of A) [[Betweenness centrality]], B) [[Closeness centrality]], C) [[Eigenvector centrality]], D) [[Degree centrality]], E) [[Centrality#Harmonic centrality|Harmonic centrality]] and F) [[Katz centrality]] of the same graph.]]&lt;br /&gt;
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Examples of A) [[Betweenness centrality, B) Closeness centrality, C) Eigenvector centrality, D) Degree centrality, E) Harmonic centrality and F) Katz centrality of the same graph.]]&lt;br /&gt;
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实例 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; a)[中介中心性A) [[Betweenness centrality,b)紧密中心性，B) Closeness centrality, c)特征向量中心性，C) Eigenvector centrality, d)度中心性，D) Degree centrality, e)调和中心性，E) Harmonic centrality andf) 卡兹Katz 中心性]F) Katz centrality .]]&amp;lt;/font&amp;gt;'''&lt;br /&gt;
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Historically first and conceptually simplest is '''degree centrality''', which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely [[indegree]] and [[outdegree]]. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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Historically first and conceptually simplest is degree centrality, which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely indegree and outdegree. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
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历史上最简单的概念是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''，它定义为一个节点上发生的链接数量(即一个节点拥有的关系数量)。度可以根据节点捕获流经网络的任何东西(例如病毒或某些信息)的直接风险来解释。在有向网络的情况下(其中联系有方向) ，我们通常定义两个独立的度量，即 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度 Outdegree&amp;lt;/font&amp;gt;'''。因此，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度indegree&amp;lt;/font&amp;gt;'''是指向该节点的关系数，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度outdegree&amp;lt;/font&amp;gt;'''是指该节点指向其他节点的关系数。当关系与一些积极的方面如友谊或合作有关时， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''通常被解释为一种形式的受欢迎，而 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度Indegree&amp;lt;/font&amp;gt;'''则被解释为合群。&lt;br /&gt;
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The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
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The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
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对于给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边，度的中心性定义为&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
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Calculating degree centrality for all the nodes in a graph takes [[big theta|&amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt;]] in a [[dense matrix|dense]] [[adjacency matrix]] representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a [[sparse matrix]] representation.&lt;br /&gt;
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Calculating degree centrality for all the nodes in a graph takes &amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt; in a dense adjacency matrix representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a sparse matrix representation.&lt;br /&gt;
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计算一个图中所有节点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''需要在图的稠密'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵Adjacency matrix &amp;lt;/font&amp;gt;'''表示中使用 Theta (v ^ 2) &amp;lt;/math &amp;gt; ，而在稀疏矩阵表示中使用 Theta (e) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of ''graph centralization''.&amp;lt;ref&amp;gt;Freeman, Linton C. &amp;quot;Centrality in social networks conceptual clarification.&amp;quot; Social networks 1.3 (1979): 215–239.&amp;lt;/ref&amp;gt; Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
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The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of graph centralization. Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
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节点级中心性的定义可以扩展到整个图，在这种情况下，我们指的是图的集中性。设 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 为 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''最高的节点。让 &amp;lt; math &amp;gt; x: = (y，z) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; | y | &amp;lt;/math &amp;gt; 节点连接图，最大化下列数量(&amp;lt; math &amp;gt; y * &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 中度最高的节点) :&lt;br /&gt;
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:&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h = sum ^ { | y | }{ j = 1}[ c _ d (y *)-c _ d (y _ j)] &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
&lt;br /&gt;
Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
&lt;br /&gt;
相应地，图形 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''如下:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ h } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a [[star graph]]), and in this case&lt;br /&gt;
&lt;br /&gt;
The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a star graph), and in this case&lt;br /&gt;
&lt;br /&gt;
当图形 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 包含一个所有其他节点都连接的中心节点(一个星形图)时，&amp;lt; math &amp;gt; h &amp;lt;/math &amp;gt; 的值最大化，在这种情况下&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
(n-1)-1) = n ^ 2-3n + 2&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
所以，对于任意的图 &amp;lt; math &amp;gt; g: = (v，e) ，&amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ | v | ^ 2-3 | v | + 2} &amp;lt;/math &amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Closeness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Closeness centrality}}In a [[Connected component (graph theory)|connected]] [[Graph (discrete mathematics)|graph]], the [[Normalization (statistics)|normalized]] '''closeness centrality''' (or '''closeness''') of a node is the average length of the [[Shortest path problem|shortest path]] between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
&lt;br /&gt;
In a connected graph, the normalized closeness centrality (or closeness) of a node is the average length of the shortest path between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
&lt;br /&gt;
在连通图中，节点的标准'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''(或贴近性)是节点与图中所有其他节点之间最短路径的平均长度。因此，一个节点越是中心，它就越接近所有其他节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Closeness was defined by [[Alex Bavelas]] (1950) as the [[Multiplicative inverse|reciprocal]] of the '''farness''',&amp;lt;ref&amp;gt;Alex Bavelas. Communication patterns in task-oriented groups. ''J. Acoust. Soc. Am'', '''22'''(6):725–730, 1950.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;{{cite journal|year=1966|title=The centrality index of a graph|url=|journal=Psychometrika|volume=31|issue=4|pages=581–603|doi=10.1007/bf02289527|pmid=5232444|hdl=10338.dmlcz/101401|last1=Sabidussi|first1=G|hdl-access=free}}&amp;lt;/ref&amp;gt; that is:&lt;br /&gt;
&lt;br /&gt;
Closeness was defined by Alex Bavelas (1950) as the reciprocal of the farness, that is:&lt;br /&gt;
&lt;br /&gt;
亚历克斯 · 巴维拉斯(1950)将亲密度定义为相对于距离的倒数，即:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
C (x) = frac {1}{ sum _ y d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the [[Distance (graph theory)|distance]] between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the distance between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; d (y，x) &amp;lt;/math &amp;gt; 是顶点 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; 之间的距离。然而，当谈到'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''时，人们通常会提到它的标准化形式，一般是以前的公式乘以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; ，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。这种调整允许比较不同大小图形的节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Taking distances ''from'' or ''to'' all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in [[directed graph]]s (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
&lt;br /&gt;
Taking distances from or to all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in directed graphs (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
&lt;br /&gt;
从所有其他节点或到所有其他节点的距离在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 无向图Undirected graphs&amp;lt;/font&amp;gt;'''中是不相关的，但是在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 有向图Directed graphs&amp;lt;/font&amp;gt;'''中可能产生完全不同的结果(例如:一个网站可以从传出链接获得高的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，而从传入链接获得低的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''）。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
===Harmonic centrality===&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the '''harmonic centrality''' reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the harmonic centrality reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
在一个(不一定是连通的)图中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''反转了'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''定义中的和互反运算:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h (x) = sum { y neq x } frac {1}{ d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; 1/d (y，x) = 0 &amp;lt;/math &amp;gt; if there is no path from &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; to &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 。调和中心性可以通过除以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; 来标准化，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Harmonic centrality was proposed by [[Massimo Marchiori|Marchiori]] and [[Vito Latora|Latora]] (2000)&amp;lt;ref name=&amp;quot;marchiorilatora2000&amp;quot;&amp;gt;{{citation| journal = Physica A: Statistical Mechanics and Its Applications  | last1 = Marchiori | first1 = Massimo | last2 = Latora | first2 = Vito | year = 2000 | volume = 285 | issue = 3–4 | pages = 539–546 | title = Harmony in the small-world | doi=10.1016/s0378-4371(00)00311-3| arxiv = cond-mat/0008357 | bibcode = 2000PhyA..285..539M }}&amp;lt;/ref&amp;gt; and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot;&amp;lt;ref&amp;gt;{{cite journal|first1=Anthony|last1=Dekker|title=Conceptual Distance in Social Network Analysis|journal=Journal of Social Structure|volume=6|issue=3|year=2005|url=http://www.cmu.edu/joss/content/articles/volume6/dekker/index.html}}&amp;lt;/ref&amp;gt; and by Rochat (2009).&amp;lt;ref&amp;gt;{{cite conference  | author = Yannick Rochat  | title = Closeness centrality extended to unconnected graphs: The harmonic centrality index | conference = Applications of Social Network Analysis, ASNA 2009 | url = http://infoscience.epfl.ch/record/200525/files/%5bEN%5dASNA09.pdf }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Harmonic centrality was proposed by Marchiori and Latora (2000) and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot; and by Rochat (2009).&lt;br /&gt;
&lt;br /&gt;
调和中心性是由 Marchiori 和 Latora (2000)提出的，然后是 Dekker (2005)独立提出的，使用的名称是“有价值的中心性” ，Rochat (2009)。&lt;br /&gt;
&lt;br /&gt;
==Betweenness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Betweenness centrality}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Graph betweenness.svg|240px|right|thumb|Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.]]&lt;br /&gt;
&lt;br /&gt;
Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.&lt;br /&gt;
&lt;br /&gt;
色调(从红色 = 0到蓝色 = max)表示节点之间的距离。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
'''Betweenness''' is a centrality measure of a [[vertex (graph theory)|vertex]] within a [[Graph (discrete mathematics)|graph]] (there is also [[edge (graph theory)|edge]] betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by [[Linton Freeman]]&amp;lt;ref name=&amp;quot;freeman1977&amp;quot;&amp;gt;{{cite journal |last1 = Freeman |first1 = Linton | year=1977| title = A set of measures of centrality based upon betweenness | journal = Sociometry| volume=40|issue = 1 | pages=35–41 | doi=10.2307/3033543|jstor = 3033543 }}&amp;lt;/ref&amp;gt; In his conception, vertices that have a high probability to occur on a randomly chosen [[shortest path problem|shortest path]] between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
&lt;br /&gt;
Betweenness is a centrality measure of a vertex within a graph (there is also edge betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by Linton Freeman In his conception, vertices that have a high probability to occur on a randomly chosen shortest path between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
&lt;br /&gt;
中介性是图中顶点的中心性度量(也有边中介性，这里没有讨论)。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''量化了一个节点沿着其他两个节点之间的最短路径充当桥梁的次数。在林顿 · 弗里曼的概念中，在两个随机选择的顶点之间随机选择的最短路径上出现概率高的顶点具有很高的中介性。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
&lt;br /&gt;
The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
&lt;br /&gt;
在一个图 &amp;lt; math &amp;gt; g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的顶点之间的距离计算如下:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
# For each pair of vertices (''s'',''t''), compute the [[Shortest path problem|shortest paths]] between them.&lt;br /&gt;
&lt;br /&gt;
 For each pair of vertices (s,t), compute the shortest paths between them.&lt;br /&gt;
&lt;br /&gt;
对于每一对顶点(s，t) ，计算它们之间的最短路径。&lt;br /&gt;
&lt;br /&gt;
# For each pair of vertices (''s'',''t''), determine the fraction of shortest paths that pass through the vertex in question (here, vertex ''v'').&lt;br /&gt;
&lt;br /&gt;
 For each pair of vertices (s,t), determine the fraction of shortest paths that pass through the vertex in question (here, vertex v).&lt;br /&gt;
&lt;br /&gt;
对于每对顶点(s，t) ，确定通过该顶点(这里是顶点 v)的最短路径的分数。&lt;br /&gt;
&lt;br /&gt;
# Sum this fraction over all pairs of vertices (''s'',''t'').&lt;br /&gt;
&lt;br /&gt;
 Sum this fraction over all pairs of vertices (s,t).&lt;br /&gt;
&lt;br /&gt;
对所有顶点对(s，t)求这个分数的和。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
More compactly the betweenness can be represented as:&amp;lt;ref name=&amp;quot;brandes&amp;quot;&amp;gt;{{cite journal |last1 = Brandes |first1 = Ulrik | year=2001 |title = A faster algorithm for betweenness centrality  | journal = Journal of Mathematical Sociology| volume=25|issue = 2 | pages=163–177| url = http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.11.2024 | accessdate = October 11, 2011| format = PDF | doi=10.1080/0022250x.2001.9990249|citeseerx = 10.1.1.11.2024 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
More compactly the betweenness can be represented as:&lt;br /&gt;
&lt;br /&gt;
更确切地说，两者之间的关系可以表示为:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
{ math &amp;gt; c _ b (v) = sum _ { s neq v neq t in v } frac { sigma _ st }(v)}{ sigma _ st } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including ''v'', which for [[Digraph (mathematics)|directed graphs]] is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected [[Star (graph theory)|star graph]], the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including v, which for directed graphs is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected star graph, the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; sigma { st } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { st }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径数。有向图是 &amp;lt; math &amp;gt; (n-1)(n-2) &amp;lt;/math &amp;gt; ，无向图是 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; 。例如，在一个无向星图中，中心顶点(包含在每个可能的最短路径中)的中介性为 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; (1，如果标准化) ，而叶子(包含在没有最短路径中)的中介性为0。&lt;br /&gt;
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From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires [[Big O notation|&amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt;]] time with the [[Floyd–Warshall algorithm]]. However, on sparse graphs, [[Johnson's algorithm]] may be more efficient, taking [[Big O notation|&amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt;]] time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm&amp;lt;ref name=brandes/&amp;gt; which takes [[Big O notation|&amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt;]] time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&amp;lt;ref name=&amp;quot;brandes&amp;quot; /&amp;gt;&lt;br /&gt;
&lt;br /&gt;
From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires &amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt; time with the Floyd–Warshall algorithm. However, on sparse graphs, Johnson's algorithm may be more efficient, taking &amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt; time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm which takes &amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt; time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&lt;br /&gt;
&lt;br /&gt;
从计算的角度来看，图中所有顶点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介和紧密中心性Betweenness and Closeness centralities&amp;lt;/font&amp;gt;'''都涉及到计算图中所有顶点对之间的最短路径，这就需要用 Floyd-Warshall 算法计算时间。然而，对于稀疏图，约翰逊算法的效率可能更高，采用 &amp;lt; math &amp;gt; o (v ^ 2 log v + v e) &amp;lt;/math &amp;gt; 时间。在不加权图的情况下，可以用 Brandes 的算法进行计算，该算法需要 &amp;lt; math &amp;gt; o (v e) &amp;lt;/math &amp;gt; 时间。一般情况下，这些算法假定图是无向的，并且连通图中允许有圈和多条边。当专门处理网络图时，图通常没有环或多条边来维持简单的关系(其中的边表示两个人或顶点之间的联系)。在这种情况下，使用 Brandes 的算法将最终的中心性分数除以2来计算每条被重复计算的最短路径。&lt;br /&gt;
&lt;br /&gt;
==Eigenvector centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Eigenvector centrality}}&lt;br /&gt;
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'''Eigenvector centrality''' (also called '''eigencentrality''') is a measure of the influence of a [[node (networking)|node]] in a [[network (mathematics)|network]]. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&amp;lt;ref&amp;gt;{{cite journal|title = The mathematics of networks|url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf|author = M. E. J. Newman|accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;/&amp;gt; [[Google]]'s [[PageRank]] and the [[Katz centrality]] are variants of the eigenvector centrality.&amp;lt;ref name=&amp;quot;ams&amp;quot;&amp;gt;{{Cite web | url=http://www.ams.org/samplings/feature-column/fcarc-pagerank | title=American Mathematical Society}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Eigenvector centrality (also called eigencentrality) is a measure of the influence of a node in a network. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''(也称为特征中心性)是衡量网络中节点影响的一个指标。它将相对得分分配给网络中的所有节点，这是基于这样一个概念: 与得分较高的节点相比，与得分较低的节点相同的连接对所涉及的节点的得分贡献更大。&lt;br /&gt;
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=== Using the adjacency matrix to find eigenvector centrality ==&lt;br /&gt;
==使用'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''发现'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the [[adjacency matrix]], i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
&lt;br /&gt;
For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the adjacency matrix, i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
&lt;br /&gt;
对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 让 &amp;lt; math &amp;gt; a = (a { v，t }) &amp;lt;/math &amp;gt; 成为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''，即。如果顶点 &amp;lt; math &amp;gt; &amp;gt; v &amp;lt;/math &amp;gt; 与 math &amp;gt; t &amp;lt;/math &amp;gt; 相连，而 &amp;lt; math &amp;gt; a { v，t } = 0 &amp;lt;/math &amp;gt; 否则。顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分可以定义为:&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
在 m (v)} x _ t = frac {1}{ lambda } sum { t in g } a { v，t } x _ t &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the [[eigenvector]] equation&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the eigenvector equation&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; m (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 和 &amp;lt; math &amp;gt; &amp;gt; lambda &amp;lt;/math &amp;gt; 的邻居集合。通过一个小的重新排列，这可以被重写成向量符号，作为特征向量方程&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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:&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
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[ math &amp;gt; mathbf { Ax } = { lambda } mathbf { x } &amp;lt;/math &amp;gt; &lt;br /&gt;
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In general, there will be many different [[eigenvalue]]s &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the [[Perron–Frobenius theorem]]. This greatest eigenvalue results in the desired centrality measure.&amp;lt;ref&amp;gt;{{cite journal  | author = M. E. J. Newman  | title = The mathematics of networks  | url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf  | accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt; The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices ''n''. [[Power iteration]] is one of many [[eigenvalue algorithm]]s that may be used to find this dominant eigenvector.&amp;lt;ref name=&amp;quot;ams&amp;quot; /&amp;gt; Furthermore, this can be generalized so that the entries in ''A'' can be real numbers representing connection strengths, as in a [[stochastic matrix]].&lt;br /&gt;
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In general, there will be many different eigenvalues &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the Perron–Frobenius theorem. This greatest eigenvalue results in the desired centrality measure. The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices n. Power iteration is one of many eigenvalue algorithms that may be used to find this dominant eigenvector. Furthermore, this can be generalized so that the entries in A can be real numbers representing connection strengths, as in a stochastic matrix.&lt;br /&gt;
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一般情况下，存在许多不同的特征值，对于这些特征值存在一个非零特征向量解。由于邻接矩阵中的条目是非负的，所以由 Perron-弗罗贝尼乌斯定理得出，它有一个实的和正的唯一最大特征值。由这个最大的特征值得出期望的中心性度量。相关特征向量的 &amp;lt; math &amp;gt; v ^ { th } &amp;lt;/math &amp;gt; 分量给出了网络中顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分。特征向量只定义了一个公共因子，所以只有顶点中心的比例是明确定义的。要定义一个绝对分数，必须对特征向量进行标准化，例如，使所有顶点的和为1或顶点的总数n。此外，这可以通用，使得 a 中的条目可以是表示连接强度的真实数字，就像'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 随机矩阵Stochastic matrix&amp;lt;/font&amp;gt;'''中一样。&lt;br /&gt;
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==Katz centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Katz centrality}}&lt;br /&gt;
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'''Katz centrality'''&amp;lt;ref&amp;gt;Katz, L. 1953. A New Status Index Derived from Sociometric Index. Psychometrika, 39–43.&amp;lt;/ref&amp;gt; is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
Katz centrality is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''是度中心性的推广。度中心性度量的是直接邻居的数量，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''度量的是通过一条路径可以连接的所有节点的数量，而远处节点的贡献会受到'''&amp;lt;font color=&amp;quot;#32CD32&amp;quot;&amp;gt; '削弱（惩罚？）Penalized&amp;lt;/font&amp;gt;''。在数学上，它被定义为&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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[数学][数学]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; (0,1) &amp;lt;/math &amp;gt; 中的衰减因子。&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''可以看作是特征向量中心性的变体。Katz 中心性的另一种形式是&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
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(x _ j + 1) &lt;br /&gt;
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Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
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Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
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与特征向量中心性的表达式相比，&amp;lt; math &amp;gt; x _ j &amp;lt;/math &amp;gt; 被 &amp;lt; math &amp;gt; x _ j + 1所代替&lt;br /&gt;
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It is shown that&amp;lt;ref&amp;gt;{{cite journal | last1 = Bonacich | first1 = P | year = 1991 | title = Simultaneous group and individual centralities | url = | journal = Social Networks | volume = 13 | issue = 2| pages = 155–168 | doi=10.1016/0378-8733(91)90018-o}}&amp;lt;/ref&amp;gt; the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
&lt;br /&gt;
It is shown that the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
&lt;br /&gt;
结果表明，主特征向量(与 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; ，邻接矩阵的最大特征值相关)是 Katz 中心性的极限，因为 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 接近 &amp;lt; math &amp;gt; tfrac {1}{ lambda } &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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== PageRank centrality ==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页分布中心性PageRank&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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{{main|PageRank}}'''[[PageRank]]''' satisfies the following equation&lt;br /&gt;
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PageRank satisfies the following equation&lt;br /&gt;
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PageRank满足下面的等式&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
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1-alpha { n } ，&amp;lt;/math &amp;gt; &lt;br /&gt;
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where&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
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其中&lt;br /&gt;
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:&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
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[ math &amp;gt; l (j) = sum { i } a { ji } &amp;lt;/math &amp;gt; &lt;br /&gt;
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is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&amp;lt;ref&amp;gt;[http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf How does Google rank webpages?] {{webarchive | url= https://web.archive.org/web/20120131083328/http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf |date=January 31, 2012 }} 20Q: About Networked Life&amp;lt;/ref&amp;gt;&lt;br /&gt;
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is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&lt;br /&gt;
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是节点 &amp;lt; math &amp;gt; j &amp;lt;/math &amp;gt; (或有向图中出站链接的数量)的邻居数量。与特征向量中心性和 Katz 中心性相比，尺度因子 &amp;lt; math &amp;gt; l (j) &amp;lt;/math &amp;gt; 是一个主要的区别。PageRank 和特征向量中心性的另一个区别是 PageRank 向量是一个左手特征向量(注意因子 &amp;lt; math &amp;gt; a _ { ji } &amp;lt;/math &amp;gt; 具有相反的索引)。&lt;br /&gt;
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==Percolation centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&amp;lt;ref name=&amp;quot;piraveenan2013&amp;quot;&amp;gt;{{cite journal |last1 = Piraveenan |first1 = M. |last2 = Prokopenko |first2 = M.|last3 = Hossain|first3 = L. |year=2013| title = Percolation Centrality: Quantifying Graph-Theoretic Impact of Nodes during Percolation in Networks | journal = PLOS One | volume=8 | issue=1 | doi=10.1371/journal.pone.0053095 | pages=e53095 | pmid=23349699 | pmc=3551907| bibcode=2013PLoSO...853095P }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&lt;br /&gt;
&lt;br /&gt;
在复杂网络中，存在大量的中心性度量来确定单个节点的“重要性”。然而，这些度量单纯从拓扑学的角度来量化节点的重要性，节点的值并不以任何方式依赖于节点的状态。不管网络动态如何，它都保持不变。即使对于加权的两者之间的度量也是如此。然而，一个节点可能很好地位于'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''或其他中心性度量的中心位置，但可能不是位于有过滤的网络的上下文中的中心位置。在许多情况下，复杂网络中都会出现“传染”现象。例如，病毒或细菌感染可以通过人们的社交网络传播，也就是所谓的接触网络。还可以在更高的抽象层次上考虑疾病的传播问题，设想通过公路、铁路或空中连接起来的城镇或人口中心网络。计算机病毒可以通过计算机网络传播。关于商业活动和交易的谣言或新闻也可以通过人们的社交网络传播。在所有这些情况下，一种“传染病”在一个复杂网络的链接上传播，随着它的传播，无论是可恢复的还是不可恢复的，都会改变节点的“状态”。例如，在流行病学方案中，随着感染扩散，个人从”易感”状态转变为”受感染”状态。在上面的例子中，随着传染的扩散，每个节点可以采取的状态可以是二进制的(例如接收/没有接收到一条新闻)、离散的(易感/受感染/康复) ，甚至是连续的(例如一个城镇中受感染的人的比例) 。这些情景的共同特点是，传染的扩散导致网络中节点状态的改变。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''（PC)就是基于这个思想而提出的，它特别地衡量了节点在协助网络渗滤方面的重要性。这项措施是由 piraveanan 等人提出的。&lt;br /&gt;
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'''Percolation centrality''' is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
&lt;br /&gt;
Percolation centrality is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''定义为在给定时间内一个给定节点的过滤路径的比例。“渗滤路径”是一对节点之间的最短路径，其中源节点被渗滤(例如，被感染)。目标节点可以是过滤的或非过滤的，或处于部分过滤状态。&lt;br /&gt;
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:&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; PC ^ t (v) = frac {1}{ N-2} sum { s neq v neq r } frac { sigma { sr }(v)}{ sigma { sr }} frac { x ^ t }{ sum {[{ x ^ t } i }}}]}}-{ x ^ t }{ v } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; σ { sr } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; r &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { sr }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径的总数。在时间 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 时，节点的过滤状态用 &amp;lt; math &amp;gt; { x ^ t } _ i &amp;lt;/math &amp;gt; 表示，两个特殊情况是当 &amp;lt; math &amp;gt; { x ^ t } _ i = 0 &amp;lt;/math &amp;gt; 表示在时间上是非过滤状态，而当 &amp;lt; math &amp;gt; &amp;lt; x ^ t &amp;lt;/math &amp;gt; i = 1 &amp;lt;/math &amp;gt; 表示在时间上是完全过滤状态。两者之间的值表示部分过滤状态(例如，在一个城镇网络中，这是该城镇感染者的百分比)。&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in [[Big O notation|&amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt;]] time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is [[Big O notation|&amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;]].&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in &amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt; time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is &amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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渗流路径的权重取决于分配给源节点的渗流水平，前提是源节点的渗流水平越高，源节点的路径就越重要。因此，位于源自高渗滤节点的最短路径上的节点可能对渗滤更为重要。PC 的定义也可以扩展到包括目标节点的权重。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''计算运行在 &amp;lt; math &amp;gt; o (NM) &amp;lt;/math &amp;gt; 时间，采用了 Brandes 快速算法的有效实现，如果计算需要考虑目标节点的权重，最坏情况下时间为 &amp;lt; math &amp;gt; o (n ^ 3) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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==Cross-clique centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 交叉团中心性Cross-clique centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
'''Cross-clique centrality''' of a single node in a complex graph determines the connectivity of a node to different [[clique (graph theory)|clique]]s. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in &amp;lt;ref name=&amp;quot;xssworms&amp;quot;&amp;gt;{{cite journal |last1 = Faghani|first1 = Mohamamd Reza| year=2013| title = A Study of XSS Worm Propagation and Detection Mechanisms in Online Social Networks | journal = IEEE Transactions on Information Forensics and Security|volume = 8|issue = 11|pages = 1815–1826|doi = 10.1109/TIFS.2013.2280884}}&amp;lt;/ref&amp;gt; but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
&lt;br /&gt;
Cross-clique centrality of a single node in a complex graph determines the connectivity of a node to different cliques. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in  but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
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复杂图中单个节点的跨团中心性决定了一个节点与不同团的连通性。具有高度跨团连通性的节点有利于信息或疾病在图中的传播。团是一种'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图Subgraphs&amp;lt;/font&amp;gt;'''，团中的每个节点都与团中的其他节点相连。对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边的交叉团连通性，定义为 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; x (v) &amp;lt;/math &amp;gt; 其中 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 所属的顶点团数。这个测度应用日久，但是在1998年由 Everett 和 Borgatti 首次提出，他们称之为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 派系重叠中心性Clique-overlap centrality&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Freeman centralization==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心度Freeman centralization&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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The '''centralization''' of any network is a measure of how central its most central node is in relation to how central all the other nodes are.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;&amp;gt;{{citation | journal = Social Networks | last1 = Freeman | first1 = Linton C. | year = 1979 | volume = 1 | issue = 3 | pages = 215–239 | title = centrality in social networks: Conceptual clarification | url = http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | doi = 10.1016/0378-8733(78)90021-7 | citeseerx = 10.1.1.227.9549 | access-date = 2014-07-31 | archive-url = https://web.archive.org/web/20160222033108/http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | archive-date = 2016-02-22 | url-status = dead }}&amp;lt;/ref&amp;gt; Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
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The centralization of any network is a measure of how central its most central node is in relation to how central all the other nodes are. Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
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任何网络的集中度都是衡量其最核心的节点相对于其他所有节点的集聚程度的标准。集中度的度量方法是: (a)计算网络中最中心的节点与所有其他节点之间的中心性差异之和; (b)将这个数量除以理论上相同规模的任何网络中这种差异之和的最大值。因此，每个中心性度量都可以有自己的集中性度量。正式定义，如果 &amp;lt; math &amp;gt; c _ x (p _ i) &amp;lt;/math &amp;gt; 是点 &amp;lt; math &amp;gt; i &amp;lt;/math &amp;gt; 的中心性度量，如果 &amp;lt; math &amp;gt; c _ x (p _ *) &amp;lt;/math &amp;gt; 是网络中最大的中心性度量，如果:&lt;br /&gt;
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:&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; max sum { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i) &amp;lt;/math &amp;gt; &lt;br /&gt;
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is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&lt;br /&gt;
&lt;br /&gt;
对于任何具有相同节点数的图来说，点中心性的最大差异是:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; c _ x = frac { sum _ { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i)}{ max sum _ { i = 1 ^ { n } c _ x (p _ *)-c _ x (p _ i)} . &amp;lt;/math &amp;gt;&lt;br /&gt;
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== Dissimilarity based centrality measures ==&lt;br /&gt;
==基于相异性的中心性度量==&lt;br /&gt;
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[[File:Srep17095-f1.jpg|thumbnail|In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.]]&lt;br /&gt;
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In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.&lt;br /&gt;
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在图示的网络中，绿色节点和红色节点最不相似，因为它们之间不共享相邻节点。因此，绿色的节点比灰色的节点对中心性的贡献更大，因为红色的节点只能通过绿色访问蓝色的节点，而灰色的节点对于红色的节点是多余的，因为它可以直接访问每个灰色的节点，而不需要任何中介。&lt;br /&gt;
&lt;br /&gt;
In order to obtain better results in the ranking of the nodes of a given network,  in &amp;lt;ref&amp;gt;{{Cite journal|title = Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|journal = Scientific Reports|date = 2015-11-25|pmc = 4658528|pmid = 26603652|volume = 5|doi = 10.1038/srep17095|first = A. J.|last = Alvarez-Socorro|first2 = G. C.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz|pages=17095|bibcode = 2015NatSR...517095A}}&amp;lt;/ref&amp;gt; are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with [[eigenvector centrality]], calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
&lt;br /&gt;
In order to obtain better results in the ranking of the nodes of a given network,  in  are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with eigenvector centrality, calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
&lt;br /&gt;
为了在给定网络节点的排序中获得更好的结果，在复杂网络中使用了相异性度量(特定于分类和数据挖掘理论)来丰富中心性度量。特征向量中心性通过求解特征值问题来计算每个节点的中心性&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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:&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
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数学，数学&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary [[Matrix similarity|dissimilarity]] matrix, defined through a dissimilitary measure, e.g., [[Jaccard index|Jaccard]] dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary dissimilarity matrix, defined through a dissimilitary measure, e.g., Jaccard dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
这里 &amp;lt; math &amp;gt; w { ij } = a { ij } d { ij } &amp;lt;/math &amp;gt; (coordinate-to-coordinate product)和 &amp;lt; math &amp;gt; d { ij } &amp;lt;/math &amp;gt; 是一个任意的不相似矩阵，通过一个双重军事度量来定义，例如，Jaccard 由&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1-dfrac { | v ^ { + }(i) cap v ^ { + }(j) | }{ | v ^ { + }(i) cup v ^ { + }(j) | } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
&lt;br /&gt;
Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
&lt;br /&gt;
这种度量允许我们量化每个节点对给定节点中心性的拓扑贡献(这就是为什么我们称之为贡献中心性) ，对那些相异性较大的节点有更多的权重/相关性，因为这些节点允许给定的节点访问那些它们自己不能直接访问的节点。&lt;br /&gt;
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Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the [[Perron–Frobenius theorem]] to ensure that the above problem has a unique solution for ''λ'' = ''λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt;'' with '''c''' non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
&lt;br /&gt;
Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the Perron–Frobenius theorem to ensure that the above problem has a unique solution for λ = λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt; with c non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
&lt;br /&gt;
值得注意的是，&amp;lt; math &amp;gt; w &amp;lt;/math &amp;gt; 是非负的，因为 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; d &amp;lt;/math &amp;gt; 都是非负矩阵，所以我们可以使用 Perron 弗罗贝尼乌斯定理来确保上述问题对于 c 非负的 = &amp;lt; sub &amp;gt; max &amp;lt;/sub &amp;gt; 有唯一的解，这样我们就可以推断出网络中每个节点的中心性。因此，i-th 节点的中心性为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1{ n } sum { j = 1} ^ { n } w { ij } c { j } ，，，，，j = 1，cdots，n &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in &amp;lt;ref&amp;gt;{{Cite web|url = http://www.nature.com/article-assets/npg/srep/2015/151125/srep17095/extref/srep17095-s1.pdf|title = Supplementary Information for Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|date = |website = |publisher = Nature Publishing Group|last = Alvarez-Socorro|first = A.J.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz}}&amp;lt;/ref&amp;gt; obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in  obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是网络中的节点数。几个不同的措施和网络进行了测试，以获得在研究案例的改善的结果。&lt;br /&gt;
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==Extensions==&lt;br /&gt;
==扩展==&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality&amp;lt;ref&amp;gt;{{cite journal | last1 = Braha | first1 = D. | last2 = Bar-Yam | first2 = Y. | year = 2006 | title = From Centrality to Temporary Fame: Dynamic Centrality in Complex Networks | url = | journal = Complexity | volume = 12 | issue = 2| pages = 59–63 | doi=10.1002/cplx.20156| arxiv = physics/0611295 | bibcode = 2006Cmplx..12b..59B }}&amp;lt;/ref&amp;gt; in the context of time-dependent and temporal networks.&amp;lt;ref&amp;gt;{{cite journal | last1 = Hill | first1 = S.A. | last2 = Braha | first2 = D. | year = 2010 | title = Dynamic Model of Time-Dependent Complex Networks | url = | journal = Physical Review E | volume = 82 | issue = 4| page = 046105 | doi=10.1103/physreve.82.046105| pmid = 21230343 | arxiv = 0901.4407 | bibcode = 2010PhRvE..82d6105H }}&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Gross, T. and Sayama, H. (Eds.). 2009. ''Adaptive Networks: Theory, Models and Applications.'' Springer.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Holme, P. and Saramäki, J. 2013. ''Temporal Networks.'' Springer.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality in the context of time-dependent and temporal networks.&lt;br /&gt;
&lt;br /&gt;
经验和理论研究已经将静态网络中的中心性概念扩展到时间依赖网络和时间网络中的动态中心性。&lt;br /&gt;
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For generalizations to weighted networks, see Opsahl et al. (2010).&amp;lt;ref&amp;gt;{{cite journal | last1 = Opsahl | first1 = Tore | last2 = Agneessens | first2 = Filip | last3 = Skvoretz | first3 = John | title = Node centrality in weighted networks: Generalizing degree and shortest paths | doi = 10.1016/j.socnet.2010.03.006 | year = 2010 | pages = 245–251 | volume = 32 | journal = Social Networks | url = http://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | issue = 3 | access-date = 2010-04-23 | archive-url = https://web.archive.org/web/20180226080331/https://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | archive-date = 2018-02-26 | url-status = dead }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
For generalizations to weighted networks, see Opsahl et al. (2010).&lt;br /&gt;
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对加权网络的推广，见 Opsahl 等人。(2010).&lt;br /&gt;
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The concept of centrality was extended to a group level as well. For example, '''group betweenness''' centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&amp;lt;ref name=&amp;quot;group1&amp;quot;&amp;gt;Everett, M. G. and Borgatti, S. P. (2005). Extending centrality. In P. J. Carrington, J. Scott and S. Wasserman (Eds.), ''Models and methods in social network analysis'' (pp. 57–76). New York: Cambridge University Press.&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;group2&amp;quot;&amp;gt;Puzis, R., Yagil, D., Elovici, Y., Braha, D. (2009).[http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf Collaborative attack on Internet users’ anonymity] {{Webarchive|url=https://web.archive.org/web/20131207133417/http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf |date=2013-12-07 }}, ''Internet Research'' '''19'''(1)&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, group betweenness centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&lt;br /&gt;
&lt;br /&gt;
中心性的概念也扩展到了群体层次。例如，组间的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''显示了连接穿过组的成对非组成员的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Geodesics &amp;lt;/font&amp;gt;'''的比例。&lt;br /&gt;
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==See also==&lt;br /&gt;
==又及==&lt;br /&gt;
* [[Alpha centrality]]&lt;br /&gt;
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* [[Core–periphery structure]]&lt;br /&gt;
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* [[Distance (graph theory)|Distance in graphs]]&lt;br /&gt;
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*阿尔法中心性&lt;br /&gt;
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*核心—外围结构&lt;br /&gt;
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*距离（图理论）图中的距离&lt;br /&gt;
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==Notes and references==&lt;br /&gt;
&lt;br /&gt;
{{Reflist}}&lt;br /&gt;
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==Further reading==&lt;br /&gt;
拓展阅读&lt;br /&gt;
* Koschützki, D.; Lehmann, K. A.; Peeters, L.; Richter, S.; Tenfelde-Podehl, D. and Zlotowski, O. (2005) Centrality Indices. In Brandes, U. and Erlebach, T. (Eds.)  ''Network Analysis: Methodological Foundations'', pp.&amp;amp;nbsp;16–61, LNCS 3418, Springer-Verlag.&lt;br /&gt;
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[[Category:Graph theory]]&lt;br /&gt;
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Category:Graph theory&lt;br /&gt;
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分类: 图论&lt;br /&gt;
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[[Category:Graph algorithms]]&lt;br /&gt;
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Category:Graph algorithms&lt;br /&gt;
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分类: 图形算法&lt;br /&gt;
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Category:Algebraic graph theory&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Centrality]]. Its edit history can be viewed at [[网络中心性/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
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		<title>网络中心性</title>
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		<updated>2020-12-04T13:17:17Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：&lt;/p&gt;
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&lt;div&gt;此词条暂由水流心不竞初译，未经审校，带来阅读不便，请见谅。&lt;br /&gt;
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{{for|the statistical concept|Central tendency}}&lt;br /&gt;
{{Network Science}}&lt;br /&gt;
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In [[graph theory]] and [[network theory|network analysis]], indicators of '''centrality''' identify the most important [[vertex (graph theory)|vertices]] within a graph. Applications include identifying the most influential person(s) in a [[social network]], key infrastructure nodes in the [[Internet]] or [[urban network]]s, and [[super-spreader]]s of disease. Centrality concepts were first developed in [[social network analysis]], and many of the terms used to measure centrality reflect their [[sociology|sociological]] origin.&amp;lt;ref name=&amp;quot;NewmanNetworks&amp;quot;&amp;gt;Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press.&amp;lt;/ref&amp;gt;&lt;br /&gt;
In graph theory and network analysis, indicators of centrality identify the most important vertices within a graph. Applications include identifying the most influential person(s) in a social network, key infrastructure nodes in the Internet or urban networks, and super-spreaders of disease. Centrality concepts were first developed in , and many of the terms used to measure centrality reflect their sociological origin.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;图论 graph theory &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络分析 network analysis &amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性 centrality &amp;lt;/font&amp;gt;'''指标用于识别图中最重要的顶点。其应用包括在社会网络中识别出最有影响力的个人，在因特网或城市网络中识别出最为关键的基础设施节点，以及识别疾病的超级传播者。中心性的概念最初由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;社会网络分析 social network analysis&amp;lt;/font&amp;gt;'''所发展，因此许多用于衡量中心性的术语都反映出了它们的社会学出身。&lt;br /&gt;
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They should not be confused with [[node influence metric]]s, which seek to quantify the influence of every node in the network.&lt;br /&gt;
They should not be confused with node influence metrics, which seek to quantify the influence of every node in the network.&lt;br /&gt;
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中心性不应与节点影响度相混淆，后者意在量化网络中每个节点的影响。&lt;br /&gt;
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==中心性指标的定义与特性Definition and characterization of centrality indices==&lt;br /&gt;
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Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;&amp;gt;{{cite journal |last1= Bonacich |first1= Phillip|year= 1987 |title= Power and Centrality: A Family of Measures | journal=American Journal of Sociology |volume= 92|issue= 5|pages= 1170–1182|doi=10.1086/228631 |url= }}&amp;lt;!--|accessdate=July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Borgatti2005&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|year= 2005 |title= Centrality and Network Flow |journal=Social Networks |volume= 27|issue= |pages= 55–71|doi=10.1016/j.socnet.2004.11.008 |url= |citeseerx= 10.1.1.387.419}}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |&lt;br /&gt;
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Centrality indices are answers to the question &amp;quot;What characterizes an important vertex?&amp;quot; The answer is given in terms of a real-valued function on the vertices of a graph, where the values produced are expected to provide a ranking which identifies the most important nodes.&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;&amp;gt;{{cite journal |&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心性指数Centrality indices &amp;lt;/font&amp;gt;'''是对“重要顶点的特征是什么”这一问题的回答，答案以图顶点的实值函数的方式给出，在这些顶点上的取值的排序标识出最重要的节点。&lt;br /&gt;
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&amp;lt; ref name = “ Christian f. a. Negre，Uriel n. Morzan，Heidi p. Hendrickson，Rhitankar Pal，George p. Lisi，j. Patrick Loria，Ivan Rivalta，Junming Ho，Victor s. Batista。2018 E12201-- E12208” &amp;gt; { cite journal | &lt;br /&gt;
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author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|&lt;br /&gt;
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author = Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista.|&lt;br /&gt;
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作者: Christian f. a. Negre，Uriel n. Morzan，Heidi p. Hendrickson，Rhitankar Pal，George p. Lisi，j. Patrick Loria，Ivan Rivalta，Junming Ho，Victor s. Batista。|&lt;br /&gt;
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title = Eigenvector centrality for characterization of protein allosteric pathways|&lt;br /&gt;
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title = Eigenvector centrality for characterization of protein allosteric pathways|&lt;br /&gt;
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蛋白质变构角色塑造的特征向量中心性&lt;br /&gt;
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journal = Proceedings of the National Academy of Sciences|&lt;br /&gt;
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journal = Proceedings of the National Academy of Sciences|&lt;br /&gt;
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日记 = 美国国家科学院院刊 | &lt;br /&gt;
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volume = 115|&lt;br /&gt;
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volume = 115|&lt;br /&gt;
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115 | &lt;br /&gt;
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number = 52|&lt;br /&gt;
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number = 52|&lt;br /&gt;
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52 | &lt;br /&gt;
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pages = E12201–E12208|&lt;br /&gt;
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pages = E12201–E12208|&lt;br /&gt;
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Pages = E12201-E12208 | &lt;br /&gt;
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year = 2018|&lt;br /&gt;
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year = 2018|&lt;br /&gt;
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2018年&lt;br /&gt;
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doi = 10.1073/pnas.1810452115|&lt;br /&gt;
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doi = 10.1073/pnas.1810452115|&lt;br /&gt;
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Doi = 10.1073/pnas. 1810452115 | &lt;br /&gt;
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pmid = 30530700|&lt;br /&gt;
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pmid = 30530700|&lt;br /&gt;
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30530700 | &lt;br /&gt;
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pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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pmc = 6310864}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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6310864} &amp;lt;/ref &amp;gt; &lt;br /&gt;
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The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
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The word &amp;quot;importance&amp;quot; has a wide number of meanings, leading to many different definitions of centrality. Two categorization schemes have been proposed.&lt;br /&gt;
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“重要性”这个词有许多含义，导致了许多不同的中心性定义。分为两类。&lt;br /&gt;
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&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important.&amp;lt;ref name=Borgatti2005/&amp;gt; &amp;quot;Importance&amp;quot; can alternatively be conceived as involvement in the cohesiveness of the network. This allows centralities to be classified based on how they measure cohesiveness.&amp;lt;ref name=&amp;quot;Borgatti2006&amp;quot;&amp;gt;{{cite journal |last1= Borgatti |first1= Stephen P.|last2= Everett |first2= Martin G.|year= 2006 |title= A Graph-Theoretic Perspective on Centrality |journal=Social Networks |volume= 28|issue= 4|pages= 466–484|doi=10.1016/j.socnet.2005.11.005 |url= }}&amp;lt;!--|accessdate= July 11, 2014--&amp;gt;&amp;lt;/ref&amp;gt; Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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&amp;quot;Importance&amp;quot; can be conceived in relation to a type of flow or transfer across the network. This allows centralities to be classified by the type of flow they consider important. Both of these approaches divide centralities in distinct categories. A further conclusion is that a centrality which is appropriate for one category will often &amp;quot;get it wrong&amp;quot; when applied to a different category.&lt;br /&gt;
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“重要性”可以被认为与一种跨网络的流动或传输有关。这允许根据它们认为重要的流类型对中心性进行分类。这两种方法都将中心性划分为不同的类别。进一步的推论是，适用于一个类别的中心性在（推广）应用于另一个类别时往往会“出错”。&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one ([[Centrality#Degree centrality|degree centrality]]) to infinite walks ([[Centrality#Eigenvector centrality|eigenvalue centrality]]).&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=&amp;quot;Benzi2013&amp;quot;&amp;gt;{{cite journal | last1=Benzi | first1=Michele | last2=Klymko| first2=Christine | year=2013 |title= A matrix analysis of different centrality measures |arxiv=1312.6722 | doi=10.1137/130950550 | volume=36 | issue=2 | journal=SIAM Journal on Matrix Analysis and Applications | pages=686–706}}&amp;lt;/ref&amp;gt; The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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When centralities are categorized by their approach to cohesiveness, it becomes apparent that the majority of centralities inhabit one category. The count of the number of walks starting from a given vertex differs only in how walks are defined and counted. Restricting consideration to this group allows for a soft characterization which places centralities on a spectrum from walks of length one (degree centrality) to infinite walks (eigenvalue centrality). The observation that many centralities share this familial relationships perhaps explains the high rank correlations between these indices.&lt;br /&gt;
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当中心性按照它们对'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 内聚性Cohesiveness&amp;lt;/font&amp;gt;'''的趋近程度来分类时，很明显，大多数中心性都集中在一个类别中。从一个给定顶点开始对步数计数，不同之处只在于行走的定义和计数方式。对该组描述的约束限制，从位置中心（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心度Degree centrality&amp;lt;/font&amp;gt;'''）到单元域（'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征中心度Eigenvalue centrality&amp;lt;/font&amp;gt;'''），观察到许多中心性都有这种相似关系，这也许可以解释这些指数之间的高阶相关性。&lt;br /&gt;
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===Characterization by network flows==&lt;br /&gt;
==网络流特征==&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at once.&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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A network can be considered a description of the paths along which something flows. This allows a characterization based on the type of flow and the type of path encoded by the centrality. A flow can be based on transfers, where each indivisible item goes from one node to another, like a package delivery going from the delivery site to the client's house. A second case is serial duplication, in which an item is replicated so that both the source and the target have it. An example is the propagation of information through gossip, with the information being propagated in a private way and with both the source and the target nodes being informed at the end of the process. The last case is parallel duplication, with the item being duplicated to several links at the same time, like a radio broadcast which provides the same information to many listeners at oe.&lt;br /&gt;
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一个网络可以被看成是对某种物体流动的路径描述。使基于流的类型和由中心性编码的路径类型（同时）得到表征。一个流可以基于传输，每个不可分割的项目从一个节点到另一个节点，就像一个包裹从配送站送到客户的房子。第二种情况是串行复制，在这种情况下，一个项从源节点被复制到达目标节点。例如通过流言传播信息，以私有方式传播信息，并在流程结束时通知源节点和目标节点。最后一种情况是并行复制，即同时将项目复制到多个链接，就像无线电广播一次性向多个听众提供相同的信息。&lt;br /&gt;
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Likewise, the type of path can be constrained to [[Distance (graph theory)|geodesics]] (shortest paths), [[Glossary of graph theory terms#path|paths]]  (no vertex is visited more than once), [[Glossary of graph theory terms#trail|trails]] (vertices can be visited multiple times, no edge is traversed more than once), or [[Glossary of graph theory terms#walk|walks]] (vertices and edges can be visited/traversed multiple times).&amp;lt;ref name=Borgatti2005/&amp;gt;&lt;br /&gt;
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Likewise, the type of path can be constrained to geodesics (shortest paths), paths  (no vertex is visited more than once), trails (vertices can be visited multiple times, no edge is traversed more than once), or walks (vertices and edges can be visited/traversed multiple times).&lt;br /&gt;
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同样，路径类型可以被限定为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Distance &amp;lt;/font&amp;gt;'''(最短路径)、路径(对顶点的访问不超过一次)、小径(可以访问多次顶点，没有边被访问超过一次)或者步子(可以访问/遍历多次顶点和边)。&lt;br /&gt;
===Characterization by walk structure===&lt;br /&gt;
==行走结构特征==&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either ''radial'' or ''medial.'' Radial centralities count walks which start/end from the given vertex. The [[Centrality#Degree centrality|degree]] and [[Centrality#Eigenvector centrality|eigenvalue]] centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's [[Centrality#Betweenness centrality|betweenness]] centrality, the number of shortest paths which pass through the given vertex.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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An alternative classification can be derived from how the centrality is constructed. This again splits into two classes. Centralities are either radial or medial. Radial centralities count walks which start/end from the given vertex. The degree and eigenvalue centralities are examples of radial centralities, counting the number of walks of length one or length infinity. Medial centralities count walks which pass through the given vertex. The canonical example is Freeman's betweenness centrality, the number of shortest paths which pass through the given vertex.&lt;br /&gt;
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可以从中心性的构造方式推导出另一种分类方法。这又分成了两个类。中心点可以是放射状的，也可以是内侧的。从给定顶点开始/结束的径向中心点数。度和特征值中心是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 径向中心Radial centralities&amp;lt;/font&amp;gt;'''的例子，计算长度为一或无穷大的行走的个数。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中间中心性Medial centralities&amp;lt;/font&amp;gt;'''计算通过给定顶点的步数。典型的例子是 弗里曼的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality,&amp;lt;/font&amp;gt;'''，即穿过给定顶点的最短路径的数量。&lt;br /&gt;
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Likewise, the counting can capture either the ''volume'' or the ''length'' of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's [[Centrality#Closeness centrality|closeness]] centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example.&amp;lt;ref name=Borgatti2006/&amp;gt; Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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Likewise, the counting can capture either the volume or the length of walks. Volume is the total number of walks of the given type. The three examples from the previous paragraph fall into this category. Length captures the distance from the given vertex to the remaining vertices in the graph. Freeman's closeness centrality, the total geodesic distance from a given vertex to all other vertices, is the best known example. Note that this classification is independent of the type of walk counted (i.e. walk, trail, path, geodesic).&lt;br /&gt;
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同样地，计数可以抓住行走的体积或长度。体积是给定类型的行走的总数。上一段的三个例子就属于这一类。长度则给出从给定顶点到图中其余顶点的距离。弗里曼 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，即从一个给定顶点到所有其他顶点的测地距离，是最著名的例子。请注意，这种分类独立于步行计数的类型(即：步行，小道，路径，测地线)。&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&amp;lt;ref name=Borgatti2006/&amp;gt;&lt;br /&gt;
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Borgatti and Everett propose that this typology provides insight into how best to compare centrality measures. Centralities placed in the same box in this 2×2  classification are similar enough to make plausible alternatives; one can reasonably compare which is better for a given application. Measures from different boxes, however, are categorically distinct. Any evaluation of relative fitness can only occur within the context of predetermining which category is more applicable, rendering the comparison moot.&lt;br /&gt;
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博尔加蒂和埃弗雷特提出，这种类型学为如何最好地比较中心性度量提出了建议。在这个22分类中，放在同一盒子中的中心点足够相似，可以做出合理的选择; 人们可以合理地比较哪个对于给定的应用更好。然而，不同盒子中的度量方法是截然不同的。只有在预先确定哪个类别更适用的情况下，对相对适应性的评估才会发生，这使得比较变得毫无意义。&lt;br /&gt;
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===Radial-volume centralities exist on a spectrum===&lt;br /&gt;
==光谱上存在的径向体积中心==&lt;br /&gt;
The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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The characterization by walk structure shows that almost all centralities in wide use are radial-volume measures. These encode the belief that a vertex's centrality is a function of the centrality of the vertices it is associated with. Centralities distinguish themselves on how association is defined.&lt;br /&gt;
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步行结构的特征表明，几乎所有广泛使用的中心性都是径向体积的衡量。这得出结论顶点的中心性是与之相关联的顶点中心性的函数。中心性根据如何定义关联而不同。&lt;br /&gt;
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Bonacich showed that if association is defined in terms of [[Glossary of graph theory terms#walk|walks]], then a family of centralities can be defined based on the length of walk considered.&amp;lt;ref name=&amp;quot;Bonacich1987&amp;quot;/&amp;gt; [[Centrality#Degree centrality|Degree centrality]] counts walks of length one, while [[Centrality#Eigenvector centrality|eigenvalue centrality]] counts walks of length infinity. Alternative definitions of association are also reasonable. [[Alpha centrality]] allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich showed that if association is defined in terms of walks, then a family of centralities can be defined based on the length of walk considered. Degree centrality counts walks of length one, while eigenvalue centrality counts walks of length infinity. Alternative definitions of association are also reasonable. Alpha centrality allows vertices to have an external source of influence. Estrada's subgraph centrality proposes only counting closed paths (triangles, squares, etc.).&lt;br /&gt;
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Bonacich 指出，如果联想是根据行走来定义的，那么可以根据考虑的行走长度来定义一个中心性家族。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''计算长度为1的行走，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征值中心性Eigenvalue centrality  &amp;lt;/font&amp;gt;'''计算长度为无穷大的行走。关联的其他定义也是合理的。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 阿尔法中心性Alpha centrality&amp;lt;/font&amp;gt;'''允许顶点有一个外部影响源。埃斯特拉达的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图中心性Subgraph centrality &amp;lt;/font&amp;gt;'''提出只计算封闭路径(三角形、正方形等)。).&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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The heart of such measures is the observation that powers of the graph's adjacency matrix gives the number of walks of length given by that power.  Similarly, the matrix exponential is also closely related to the number of walks of a given length. An initial transformation of the adjacency matrix allows a different definition of the type of walk counted. Under either approach, the centrality of a vertex can be expressed as an infinite sum, either&lt;br /&gt;
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这些测量方法的核心是这种现象：图中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵&amp;lt;/font&amp;gt;'''的幂给出了由该幂给出的散步长度的数目。同样，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 矩阵指数Matrix exponential&amp;lt;/font&amp;gt;'''也与给定长度的行走次数密切相关。邻接矩阵的初始转换允许对步行计数的类型进行不同的定义。无论采用哪种方法，顶点的中心性都可以表示为无穷和&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty A_{R}^{k} \beta^k &amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum _ { k = 0} ^ infty a _ { r } ^ { k } beta ^ k &amp;lt;/math &amp;gt; &lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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for matrix powers or&lt;br /&gt;
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矩阵能量或者&lt;br /&gt;
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:&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\sum_{k=0}^\infty \frac{(A_R \beta)^k}{k!}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; sum { k = 0} ^ infty frac {(a _ r beta) ^ k }{ k！{/math &amp;gt; &lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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for matrix exponentials, where&lt;br /&gt;
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对于矩阵指数函数，其中&lt;br /&gt;
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* &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; is walk length,&lt;br /&gt;
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* &amp;lt;math&amp;gt;A_R&amp;lt;/math&amp;gt; is the transformed adjacency matrix, and&lt;br /&gt;
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* &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; is a discount parameter which ensures convergence of the sum.&lt;br /&gt;
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K为步长，A_R是邻接矩阵的转秩，贝达是保证收敛的折扣参数。&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. [[Alpha centrality]] replaces the adjacency matrix with its [[resolvent formalism|resolvent]]. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to [[Centrality#Degree centrality|degree centrality]]. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to [[Centrality#Eigenvector centrality|eigenvalue centrality]].&amp;lt;ref name=Benzi2013/&amp;gt;&lt;br /&gt;
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Bonacich's family of measures does not transform the adjacency matrix. Alpha centrality replaces the adjacency matrix with its resolvent. Subgraph centrality replaces the adjacency matrix with its trace. A startling conclusion is that regardless of the initial transformation of the adjacency matrix, all such approaches have common limiting behavior. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches zero, the indices converge to degree centrality. As &amp;lt;math&amp;gt;\beta&amp;lt;/math&amp;gt; approaches its maximal value, the indices converge to eigenvalue centrality.&lt;br /&gt;
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博纳奇的一系列措施并没有改变邻接矩阵。阿尔法集中性用它的解决方案替代了邻接矩阵。子图集中性用它的踪迹取代了邻接矩阵。一个令人吃惊的结论是，不管邻接矩阵最初的转变是什么，所有这些方法都有共同的限制行为。随着贝塔系数趋近于零，指数收敛到度中心性。随着贝塔系数接近其最大值，指数收敛到特征值的中心性。&lt;br /&gt;
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===Game-theoretic centrality===&lt;br /&gt;
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=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
&lt;br /&gt;
The common feature of most of the aforementioned standard measures is that they assess the importance of a node by focusing only on the role that a node plays by itself. However, in many applications such an approach is inadequate because of synergies that may occur&lt;br /&gt;
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上述大多数标准措施的共同特点是，它们通过只关注一个节点本身所扮演的角色来评估确定节点的重要性。然而, 在许多应用中，这种方法是不充分的，因为可能会发生协同作用&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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if the functioning of nodes is considered in groups.&lt;br /&gt;
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如果将节点的功能分组考虑。&lt;br /&gt;
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[[File:Game-theoretic centrality.png|Example of game-theoretic centrality]]&lt;br /&gt;
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Example of game-theoretic centrality&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''的例子&lt;br /&gt;
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For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in &amp;lt;ref&amp;gt;Michalak, Aadithya, Szczepański, Ravindran, &amp;amp; Jennings {{ArXiv|1402.0567}}&amp;lt;/ref&amp;gt; uses the [[Shapley value]]. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
&lt;br /&gt;
For example, consider the problem of stopping an epidemic. Looking at above image of network, which nodes should we vaccinate? Based on previously described measures, we want to recognize nodes that are the most important in disease spreading. Approaches based only on centralities, that focus on individual features of nodes, may not be good idea. Nodes in the red square, individually cannot stop disease spreading, but considering them as a group, we clearly see that they can stop disease if it has started in nodes &amp;lt;math&amp;gt;v_1&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;v_4&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;v_5&amp;lt;/math&amp;gt;. Game-theoretic centralities try to consult described problems and opportunities, using tools from game-theory. The approach proposed in  uses the Shapley value. Because of the time-complexity hardness of the Shapley value calculation, most efforts in this domain are driven into implementing new algorithms and methods which rely on a peculiar topology of the network or a special character of the problem. Such an approach may lead to reducing time-complexity from exponential to polynomial.&lt;br /&gt;
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例如，考虑阻止流行病的问题。看看上面的网络图像，我们应该给哪些节点接种疫苗？基于前面描述的措施，我们希望识别在疾病传播中最重要的节点。仅仅基于中心的方法，即关注节点的个别特性，可能不是一个好主意。红色方块中的节点，单独不能阻止疾病的传播，但把它们作为一个群体来考虑，我们清楚地看到，如果疾病在节点 &amp;lt; math &amp;gt; v _ 1 &amp;lt;/math &amp;gt; 、 &amp;lt; math &amp;gt; v _ 4 &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; v _ 5 &amp;lt;/math &amp;gt; 中开始，它们就能阻止疾病的传播。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 博弈论中心性Game-theoretic centrality&amp;lt;/font&amp;gt;'''试图利用博弈论中的工具来研究所描述的问题和机会。本文提出的方法使用了 Shapley 值。由于 Shapley 值计算的时间复杂性，这一领域的大部分工作都集中在实现新的算法和方法，这些算法和方法依赖于网络的特殊拓扑结构或问题的特殊性质。这种方法可以将时间复杂度从指数级降低到多项式级。&lt;br /&gt;
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Similarly, the solution concept [[authority distribution]] (&amp;lt;ref&amp;gt;{{cite journal |last=Hu |first=Xingwei |first2=Lloyd |last2=Shapley |title=On Authority Distributions in Organizations |journal=Games and Economic Behavior |volume=45 |pages=132–170 |year=2003 | doi = 10.1016/s0899-8256(03)00130-1 }}&amp;lt;/ref&amp;gt;) applies the [[Shapley-Shubik power index]], rather than the [[Shapley value]], to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020)&amp;lt;ref&amp;gt;{{cite journal|last=Hu|first=Xingwei|year=2020|volume=7|title=Sorting big data by revealed preference with application to college ranking |journal=Journal of Big Data|doi=10.1186/s40537-020-00300-1|doi-access=free}}&amp;lt;/ref&amp;gt;, such as ranking U.S. colleges.&lt;br /&gt;
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Similarly, the solution concept authority distribution () applies the Shapley-Shubik power index, rather than the Shapley value, to measure the bilateral direct influence between the players. The distribution is indeed a type of engenvector centrality. It is used to sort big data objects in Hu (2020), such as ranking U.S. colleges.&lt;br /&gt;
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同样，'''&amp;lt;font color=&amp;quot;#CD32CD&amp;quot;&amp;gt; 加权分布概念的解()The solution concept authority distribution () &amp;lt;/font&amp;gt;'''采用 Shapley-Shubik 幂指数，而不是 Shapley 值来衡量双方之间的直接影响。这种分布确实是一种产生'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 特征向量中心性Engenvector centrality&amp;lt;/font&amp;gt;'''的类型。它用于对 Hu (2020)中的大数据对象进行排序，比如美国大学排名。&lt;br /&gt;
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== Important limitations ==&lt;br /&gt;
==重要限制==&lt;br /&gt;
Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the [[Krackhardt kite graph]], for which three different notions of centrality give three different choices of the most central vertex.&amp;lt;ref&amp;gt;{{cite journal|title=Assessing the Political Landscape: Structure, Cognition, and Power in Organizations|first=David|last=Krackhardt|authorlink=David Krackhardt|journal=Administrative Science Quarterly|volume=35|issue=2|date=June 1990|pages=342–369|doi=10.2307/2393394|jstor=2393394}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Centrality indices have two important limitations, one obvious and the other subtle. The obvious limitation is that a centrality which is optimal for one application is often sub-optimal for a different application. Indeed, if this were not so, we would not need so many different centralities. An illustration of this phenomenon is provided by the Krackhardt kite graph, for which three different notions of centrality give three different choices of the most central vertex.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中心性Centrality&amp;lt;/font&amp;gt;'''指标有两个重要的局限性，一个显而易见，另一个则不易察觉。显而易见的局限性是，对于一个应用最优的中心性对于另一个应用常常是次优的。事实上，如果不是这样，我们就不需要这么多不同的中心性。克拉克哈特风筝图为这一现象提供了一个例证，对于这个图，三个不同的中心性概念给出了三个最中心顶点的不同选择。&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices.&amp;lt;ref name=Bonacich1987/&amp;gt;&amp;lt;ref name=Borgatti2005/&amp;gt; This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  [[node influence metric]]s to address this problem.&lt;br /&gt;
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The more subtle limitation is the commonly held fallacy that vertex centrality indicates the relative importance of vertices. Centrality indices are explicitly designed to produce a ranking which allows indication of the most important vertices. This they do well, under the limitation just noted. They are not designed to measure the influence of nodes in general. Recently, network physicists have begun developing  node influence metrics to address this problem.&lt;br /&gt;
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更不易察觉的限制是通常会错误地认为顶点中心性表示顶点的相对重要性。中心性指数被明确地设计来产生一个指出最重要顶点的排名。在刚才提到的限制下，他们做得很好。它们通常不用来测量节点的影响力。最近，网络物理学家开始开发'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;节点影响度量Node influence metrics &amp;lt;/font&amp;gt;'''来解决这个问题。&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying [[Centrality#Freeman centralization|Freeman centralization]] to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt; This approach, however, is seldom seen in practice.{{citation needed|reason=I've come across quite some theoretical studies that indicate otherwise. My suggestion is to remove this sentence, if reasonable citation is not provided.|date=September 2015}}&lt;br /&gt;
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The error is two-fold. Firstly, a ranking only orders vertices by importance, it does not quantify the difference in importance between different levels of the ranking. This may be mitigated by applying Freeman centralization to the centrality measure in question, which provide some insight to the importance of nodes depending on the differences of their centralization scores. Furthermore, Freeman centralization enables one to compare several networks by comparing their highest centralization scores. This approach, however, is seldom seen in practice.&lt;br /&gt;
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错误有两方面。首先，一个排名只根据顶点的重要性排序，它并不对节点重要性的不同水平进行量化区分。这可以通过将 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;'''应用到中心性度量来缓解，这种度量可以根据节点的不同中心性得分来判断节点的重要性。此外， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心性Freeman centralization&amp;lt;/font&amp;gt;''使人们能够通过比较几个网络的最高中心性得分来比较它们。然而，这种方法在实践中很少见到。&lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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Secondly, the features which (correctly) identify the most important vertices in a given network/application do not necessarily generalize to the remaining vertices. &lt;br /&gt;
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其次，用以(正确地)识别给定网络/应用中最重要顶点的特征并不一定可推广到其余顶点。&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot; /&amp;gt;&amp;lt;ref name=&amp;quot;daSilva2012&amp;quot;&amp;gt;{{cite journal | last1=da Silva|first1=Renato |last2=Viana|first2=Matheus|last3=da F. Costa |first3=Luciano| title=Predicting epidemic outbreak from individual features of the spreaders| journal=J. Stat. Mech.: Theory Exp. | year=2012|volume=2012|pages=P07005|number=7 | doi=10.1088/1742-5468/2012/07/p07005|arxiv=1202.0024|bibcode=2012JSMTE..07..005A}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Bauer2012&amp;quot;&amp;gt;{{cite journal | last1=Bauer|first1=Frank | last2=Lizier|first2=Joseph|title=Identifying influential spreaders and efficiently estimating infection numbers in epidemic models: A walk counting approach| journal=Europhys Lett | year=2012| volume=99| pages=68007|number=6 | doi=10.1209/0295-5075/99/68007|arxiv=1203.0502|bibcode=2012EL.....9968007B}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Sikic2013&amp;quot;&amp;gt;{{ cite journal| last1= Sikic| first1=Mile|last2=Lancic|first2=Alen|last3=Antulov-Fantulin|first3=Nino|last4=Stefanic|first4=Hrvoje| title = Epidemic centrality -- is there an underestimated epidemic impact of network peripheral nodes? |journal = The European Physical Journal B |volume=86 |number=10 |pages=1–13 |year=2013 | doi=10.1140/epjb/e2013-31025-5|arxiv=1110.2558 | bibcode=2013EPJB...86..440S}}&amp;lt;/ref&amp;gt; This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&amp;lt;ref name=&amp;quot;Ghoshal2011&amp;quot;&amp;gt;{{cite journal | last1=Ghoshal | first1= G. | last2= Barabsi |first2= A L | title = Ranking stability and super-stable nodes in complex networks. | journal = Nat Commun | volume =2 | page = 394| year= 2011 | doi=10.1038/ncomms1396 | pmid= 21772265 | bibcode=2011NatCo...2..394G | doi-access= free }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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For the majority of other network nodes the rankings may be meaningless. This explains why, for example, only the first few results of a Google image search appear in a reasonable order. The pagerank is a highly unstable measure, showing frequent rank reversals after small adjustments of the jump parameter.&lt;br /&gt;
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对于大多数其他网络节点，排名可能是没有意义的。这就解释了为什么，例如，只有谷歌图片搜索的前几个结果以合理的顺序出现。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页排名Pagerank&amp;lt;/font&amp;gt;'''是一个非常不稳定的度量，显示了在跳转参数小的调整之后频繁的秩逆转。&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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While the failure of centrality indices to generalize to the rest of the network may at first seem counter-intuitive, it follows directly from the above definitions.&lt;br /&gt;
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虽然中心性指数未能推广到网络的其他部分，乍看起来似乎是违反直觉的，但它直接遵循上述定义。&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&amp;lt;ref name=&amp;quot;Lawyer2015&amp;quot;&amp;gt;{{cite journal |last1= Lawyer |first1= Glenn |year= 2015 |title= Understanding the spreading power of all nodes in a network: a continuous-time perspective |journal=Sci Rep |volume=5|pages=8665|doi=10.1038/srep08665 |pmid=25727453 |pmc=4345333|arxiv=1405.6707|bibcode=2015NatSR...5E8665L}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Complex networks have heterogeneous topology. To the extent that the optimal measure depends on the network structure of the most important vertices, a measure which is optimal for such vertices is sub-optimal for the remainder of the network.&lt;br /&gt;
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复杂网络具有异构的拓扑结构。由于最佳度量取决于最重要顶点的网络结构，对于这些顶点最优的度量对于网络的其余部分是次优的。&lt;br /&gt;
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==Degree centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Degree (graph theory)}} &lt;br /&gt;
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[[File:6 centrality measures.png|thumb|right|300px|Examples of A) [[Betweenness centrality]], B) [[Closeness centrality]], C) [[Eigenvector centrality]], D) [[Degree centrality]], E) [[Centrality#Harmonic centrality|Harmonic centrality]] and F) [[Katz centrality]] of the same graph.]]&lt;br /&gt;
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Examples of A) [[Betweenness centrality, B) Closeness centrality, C) Eigenvector centrality, D) Degree centrality, E) Harmonic centrality and F) Katz centrality of the same graph.]]&lt;br /&gt;
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实例 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; a)[中介中心性A) [[Betweenness centrality,b)紧密中心性，B) Closeness centrality, c)特征向量中心性，C) Eigenvector centrality, d)度中心性，D) Degree centrality, e)调和中心性，E) Harmonic centrality andf) 卡兹Katz 中心性]F) Katz centrality .]]&amp;lt;/font&amp;gt;'''&lt;br /&gt;
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Historically first and conceptually simplest is '''degree centrality''', which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely [[indegree]] and [[outdegree]]. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
&lt;br /&gt;
Historically first and conceptually simplest is degree centrality, which is defined as the number of links incident upon a node (i.e., the number of ties that a node has). The degree can be interpreted in terms of the immediate risk of a node for catching whatever is flowing through the network (such as a virus, or some information). In the case of a directed network (where ties have direction), we usually define two separate measures of degree centrality, namely indegree and outdegree. Accordingly, indegree is a count of the number of ties directed to the node and outdegree is the number of ties that the node directs to others. When ties are associated to some positive aspects such as friendship or collaboration, indegree is often interpreted as a form of popularity, and outdegree as gregariousness.&lt;br /&gt;
&lt;br /&gt;
历史上最简单的概念是'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''，它定义为一个节点上发生的链接数量(即一个节点拥有的关系数量)。度可以根据节点捕获流经网络的任何东西(例如病毒或某些信息)的直接风险来解释。在有向网络的情况下(其中联系有方向) ，我们通常定义两个独立的度量，即 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度 Outdegree&amp;lt;/font&amp;gt;'''。因此，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度indegree&amp;lt;/font&amp;gt;'''是指向该节点的关系数，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度outdegree&amp;lt;/font&amp;gt;'''是指该节点指向其他节点的关系数。当关系与一些积极的方面如友谊或合作有关时， '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 入度Indegree&amp;lt;/font&amp;gt;'''通常被解释为一种形式的受欢迎，而 '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 出度Indegree&amp;lt;/font&amp;gt;'''则被解释为合群。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
&lt;br /&gt;
The degree centrality of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;, for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as&lt;br /&gt;
&lt;br /&gt;
对于给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边，度的中心性定义为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(v)= \deg(v)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Calculating degree centrality for all the nodes in a graph takes [[big theta|&amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt;]] in a [[dense matrix|dense]] [[adjacency matrix]] representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a [[sparse matrix]] representation.&lt;br /&gt;
&lt;br /&gt;
Calculating degree centrality for all the nodes in a graph takes &amp;lt;math&amp;gt;\Theta(V^2)&amp;lt;/math&amp;gt; in a dense adjacency matrix representation of the graph, and for edges takes &amp;lt;math&amp;gt;\Theta(E)&amp;lt;/math&amp;gt; in a sparse matrix representation.&lt;br /&gt;
&lt;br /&gt;
计算一个图中所有节点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''需要在图的稠密'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵Adjacency matrix &amp;lt;/font&amp;gt;'''表示中使用 Theta (v ^ 2) &amp;lt;/math &amp;gt; ，而在稀疏矩阵表示中使用 Theta (e) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of ''graph centralization''.&amp;lt;ref&amp;gt;Freeman, Linton C. &amp;quot;Centrality in social networks conceptual clarification.&amp;quot; Social networks 1.3 (1979): 215–239.&amp;lt;/ref&amp;gt; Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
&lt;br /&gt;
The definition of centrality on the node level can be extended to the whole graph, in which case we are speaking of graph centralization. Let &amp;lt;math&amp;gt;v*&amp;lt;/math&amp;gt; be the node with highest degree centrality in &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;X:=(Y,Z)&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;|Y|&amp;lt;/math&amp;gt;-node connected graph that maximizes the following quantity (with &amp;lt;math&amp;gt;y*&amp;lt;/math&amp;gt; being the node with highest degree centrality in &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt;):&lt;br /&gt;
&lt;br /&gt;
节点级中心性的定义可以扩展到整个图，在这种情况下，我们指的是图的集中性。设 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 为 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 中'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''最高的节点。让 &amp;lt; math &amp;gt; x: = (y，z) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; | y | &amp;lt;/math &amp;gt; 节点连接图，最大化下列数量(&amp;lt; math &amp;gt; y * &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 中度最高的节点) :&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;H= \sum^{|Y|}_{j=1} [C_D(y*)-C_D(y_j)]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h = sum ^ { | y | }{ j = 1}[ c _ d (y *)-c _ d (y _ j)] &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
&lt;br /&gt;
Correspondingly, the degree centralization of the graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is as follows:&lt;br /&gt;
&lt;br /&gt;
相应地，图形 &amp;lt; math &amp;gt; g &amp;lt;/math &amp;gt; 的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 度中心性Degree centrality&amp;lt;/font&amp;gt;'''如下:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)]}{H}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ h } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a [[star graph]]), and in this case&lt;br /&gt;
&lt;br /&gt;
The value of &amp;lt;math&amp;gt;H&amp;lt;/math&amp;gt; is maximized when the graph &amp;lt;math&amp;gt;X&amp;lt;/math&amp;gt; contains one central node to which all other nodes are connected (a star graph), and in this case&lt;br /&gt;
&lt;br /&gt;
当图形 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 包含一个所有其他节点都连接的中心节点(一个星形图)时，&amp;lt; math &amp;gt; h &amp;lt;/math &amp;gt; 的值最大化，在这种情况下&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;H=(n-1)\cdot((n-1)-1)=n^2-3n+2.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
(n-1)-1) = n ^ 2-3n + 2&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
So, for any graph &amp;lt;math&amp;gt;G:=(V,E),&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
所以，对于任意的图 &amp;lt; math &amp;gt; g: = (v，e) ，&amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;C_D(G)= \frac{\sum^{|V|}_{i=1} [C_D(v*)-C_D(v_i)] }{|V|^2-3|V|+2}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; c _ d (g) = frac { sum ^ { | v | } _ { i = 1}[ c _ d (v *)-c _ d (v _ i)]}{ | v | ^ 2-3 | v | + 2} &amp;lt;/math &amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Closeness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Closeness centrality}}In a [[Connected component (graph theory)|connected]] [[Graph (discrete mathematics)|graph]], the [[Normalization (statistics)|normalized]] '''closeness centrality''' (or '''closeness''') of a node is the average length of the [[Shortest path problem|shortest path]] between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
&lt;br /&gt;
In a connected graph, the normalized closeness centrality (or closeness) of a node is the average length of the shortest path between the node and all other nodes in the graph. Thus the more central a node is, the closer it is to all other nodes.&lt;br /&gt;
&lt;br /&gt;
在连通图中，节点的标准'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''(或贴近性)是节点与图中所有其他节点之间最短路径的平均长度。因此，一个节点越是中心，它就越接近所有其他节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Closeness was defined by [[Alex Bavelas]] (1950) as the [[Multiplicative inverse|reciprocal]] of the '''farness''',&amp;lt;ref&amp;gt;Alex Bavelas. Communication patterns in task-oriented groups. ''J. Acoust. Soc. Am'', '''22'''(6):725–730, 1950.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;{{cite journal|year=1966|title=The centrality index of a graph|url=|journal=Psychometrika|volume=31|issue=4|pages=581–603|doi=10.1007/bf02289527|pmid=5232444|hdl=10338.dmlcz/101401|last1=Sabidussi|first1=G|hdl-access=free}}&amp;lt;/ref&amp;gt; that is:&lt;br /&gt;
&lt;br /&gt;
Closeness was defined by Alex Bavelas (1950) as the reciprocal of the farness, that is:&lt;br /&gt;
&lt;br /&gt;
亚历克斯 · 巴维拉斯(1950)将亲密度定义为相对于距离的倒数，即:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;C(x)= \frac{1}{\sum_y d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
C (x) = frac {1}{ sum _ y d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the [[Distance (graph theory)|distance]] between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;d(y,x)&amp;lt;/math&amp;gt; is the distance between vertices &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt;. However, when speaking of closeness centrality, people usually refer to its normalized form, generally given by the previous formula multiplied by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph. This adjustment allows comparisons between nodes of graphs of different sizes.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; d (y，x) &amp;lt;/math &amp;gt; 是顶点 &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; 之间的距离。然而，当谈到'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''时，人们通常会提到它的标准化形式，一般是以前的公式乘以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; ，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。这种调整允许比较不同大小图形的节点。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Taking distances ''from'' or ''to'' all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in [[directed graph]]s (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
&lt;br /&gt;
Taking distances from or to all other nodes is irrelevant in undirected graphs, whereas it can produce totally different results in directed graphs (e.g. a website can have a high closeness centrality from outgoing link, but low closeness centrality from incoming links).&lt;br /&gt;
&lt;br /&gt;
从所有其他节点或到所有其他节点的距离在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 无向图Undirected graphs&amp;lt;/font&amp;gt;'''中是不相关的，但是在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 有向图Directed graphs&amp;lt;/font&amp;gt;'''中可能产生完全不同的结果(例如:一个网站可以从传出链接获得高的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''，而从传入链接获得低的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''）。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
===Harmonic centrality===&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the '''harmonic centrality''' reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
In a (not necessarily connected) graph, the harmonic centrality reverses the sum and reciprocal operations in the definition of closeness centrality:&lt;br /&gt;
&lt;br /&gt;
在一个(不一定是连通的)图中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 调和中心性Harmonic centrality&amp;lt;/font&amp;gt;'''反转了'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 紧密中心性Closeness centrality&amp;lt;/font&amp;gt;'''定义中的和互反运算:&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
: &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
 &amp;lt;math&amp;gt;H(x)= \sum_{y \neq x} \frac{1}{d(y,x)}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; h (x) = sum { y neq x } frac {1}{ d (y，x)} &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;1 / d(y,x) = 0&amp;lt;/math&amp;gt; if there is no path from &amp;lt;math&amp;gt;y&amp;lt;/math&amp;gt; to &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt;. Harmonic centrality can be normalized by dividing by &amp;lt;math&amp;gt;N-1&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N&amp;lt;/math&amp;gt; is the number of nodes in the graph.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; 1/d (y，x) = 0 &amp;lt;/math &amp;gt; if there is no path from &amp;lt; math &amp;gt; y &amp;lt;/math &amp;gt; to &amp;lt; math &amp;gt; x &amp;lt;/math &amp;gt; 。调和中心性可以通过除以 &amp;lt; math &amp;gt; N-1 &amp;lt;/math &amp;gt; 来标准化，其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是图中的节点数。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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Harmonic centrality was proposed by [[Massimo Marchiori|Marchiori]] and [[Vito Latora|Latora]] (2000)&amp;lt;ref name=&amp;quot;marchiorilatora2000&amp;quot;&amp;gt;{{citation| journal = Physica A: Statistical Mechanics and Its Applications  | last1 = Marchiori | first1 = Massimo | last2 = Latora | first2 = Vito | year = 2000 | volume = 285 | issue = 3–4 | pages = 539–546 | title = Harmony in the small-world | doi=10.1016/s0378-4371(00)00311-3| arxiv = cond-mat/0008357 | bibcode = 2000PhyA..285..539M }}&amp;lt;/ref&amp;gt; and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot;&amp;lt;ref&amp;gt;{{cite journal|first1=Anthony|last1=Dekker|title=Conceptual Distance in Social Network Analysis|journal=Journal of Social Structure|volume=6|issue=3|year=2005|url=http://www.cmu.edu/joss/content/articles/volume6/dekker/index.html}}&amp;lt;/ref&amp;gt; and by Rochat (2009).&amp;lt;ref&amp;gt;{{cite conference  | author = Yannick Rochat  | title = Closeness centrality extended to unconnected graphs: The harmonic centrality index | conference = Applications of Social Network Analysis, ASNA 2009 | url = http://infoscience.epfl.ch/record/200525/files/%5bEN%5dASNA09.pdf }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Harmonic centrality was proposed by Marchiori and Latora (2000) and then independently by Dekker (2005), using the name &amp;quot;valued centrality,&amp;quot; and by Rochat (2009).&lt;br /&gt;
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调和中心性是由 Marchiori 和 Latora (2000)提出的，然后是 Dekker (2005)独立提出的，使用的名称是“有价值的中心性” ，Rochat (2009)。&lt;br /&gt;
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==Betweenness centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{Main|Betweenness centrality}}&lt;br /&gt;
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[[File:Graph betweenness.svg|240px|right|thumb|Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.]]&lt;br /&gt;
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Hue (from red&amp;amp;nbsp;=&amp;amp;nbsp;0 to blue&amp;amp;nbsp;=&amp;amp;nbsp;max) shows the node betweenness.&lt;br /&gt;
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色调(从红色 = 0到蓝色 = max)表示节点之间的距离。&lt;br /&gt;
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'''Betweenness''' is a centrality measure of a [[vertex (graph theory)|vertex]] within a [[Graph (discrete mathematics)|graph]] (there is also [[edge (graph theory)|edge]] betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by [[Linton Freeman]]&amp;lt;ref name=&amp;quot;freeman1977&amp;quot;&amp;gt;{{cite journal |last1 = Freeman |first1 = Linton | year=1977| title = A set of measures of centrality based upon betweenness | journal = Sociometry| volume=40|issue = 1 | pages=35–41 | doi=10.2307/3033543|jstor = 3033543 }}&amp;lt;/ref&amp;gt; In his conception, vertices that have a high probability to occur on a randomly chosen [[shortest path problem|shortest path]] between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
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Betweenness is a centrality measure of a vertex within a graph (there is also edge betweenness, which is not discussed here). Betweenness centrality quantifies the number of times a node acts as a bridge along the shortest path between two other nodes. It was introduced as a measure for quantifying the control of a human on the communication between other humans in a social network by Linton Freeman In his conception, vertices that have a high probability to occur on a randomly chosen shortest path between two randomly chosen vertices have a high betweenness.&lt;br /&gt;
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中介性是图中顶点的中心性度量(也有边中介性，这里没有讨论)。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''量化了一个节点沿着其他两个节点之间的最短路径充当桥梁的次数。在林顿 · 弗里曼的概念中，在两个随机选择的顶点之间随机选择的最短路径上出现概率高的顶点具有很高的中介性。&lt;br /&gt;
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The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
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The betweenness of a vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in a graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt; vertices is computed as follows:&lt;br /&gt;
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在一个图 &amp;lt; math &amp;gt; g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的顶点之间的距离计算如下:&lt;br /&gt;
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# For each pair of vertices (''s'',''t''), compute the [[Shortest path problem|shortest paths]] between them.&lt;br /&gt;
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 For each pair of vertices (s,t), compute the shortest paths between them.&lt;br /&gt;
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对于每一对顶点(s，t) ，计算它们之间的最短路径。&lt;br /&gt;
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# For each pair of vertices (''s'',''t''), determine the fraction of shortest paths that pass through the vertex in question (here, vertex ''v'').&lt;br /&gt;
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 For each pair of vertices (s,t), determine the fraction of shortest paths that pass through the vertex in question (here, vertex v).&lt;br /&gt;
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对于每对顶点(s，t) ，确定通过该顶点(这里是顶点 v)的最短路径的分数。&lt;br /&gt;
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# Sum this fraction over all pairs of vertices (''s'',''t'').&lt;br /&gt;
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 Sum this fraction over all pairs of vertices (s,t).&lt;br /&gt;
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对所有顶点对(s，t)求这个分数的和。&lt;br /&gt;
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More compactly the betweenness can be represented as:&amp;lt;ref name=&amp;quot;brandes&amp;quot;&amp;gt;{{cite journal |last1 = Brandes |first1 = Ulrik | year=2001 |title = A faster algorithm for betweenness centrality  | journal = Journal of Mathematical Sociology| volume=25|issue = 2 | pages=163–177| url = http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.11.2024 | accessdate = October 11, 2011| format = PDF | doi=10.1080/0022250x.2001.9990249|citeseerx = 10.1.1.11.2024 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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More compactly the betweenness can be represented as:&lt;br /&gt;
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更确切地说，两者之间的关系可以表示为:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_B(v)= \sum_{s \neq v \neq t \in V}\frac{\sigma_{st}(v)}{\sigma_{st}}&amp;lt;/math&amp;gt;&lt;br /&gt;
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{ math &amp;gt; c _ b (v) = sum _ { s neq v neq t in v } frac { sigma _ st }(v)}{ sigma _ st } &amp;lt;/math &amp;gt; &lt;br /&gt;
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&lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including ''v'', which for [[Digraph (mathematics)|directed graphs]] is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected [[Star (graph theory)|star graph]], the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
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where &amp;lt;math&amp;gt;\sigma_{st}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{st}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;.  The betweenness may be normalised by dividing through the number of pairs of vertices not including v, which for directed graphs is &amp;lt;math&amp;gt;(n-1)(n-2)&amp;lt;/math&amp;gt; and for undirected graphs is &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt;.  For example, in an undirected star graph, the center vertex (which is contained in every possible shortest path) would have a betweenness of &amp;lt;math&amp;gt;(n-1)(n-2)/2&amp;lt;/math&amp;gt; (1, if normalised) while the leaves (which are contained in no shortest paths) would have a betweenness of 0.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; sigma { st } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { st }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径数。有向图是 &amp;lt; math &amp;gt; (n-1)(n-2) &amp;lt;/math &amp;gt; ，无向图是 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; 。例如，在一个无向星图中，中心顶点(包含在每个可能的最短路径中)的中介性为 &amp;lt; math &amp;gt; (n-1)(n-2)/2 &amp;lt;/math &amp;gt; (1，如果标准化) ，而叶子(包含在没有最短路径中)的中介性为0。&lt;br /&gt;
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From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires [[Big O notation|&amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt;]] time with the [[Floyd–Warshall algorithm]]. However, on sparse graphs, [[Johnson's algorithm]] may be more efficient, taking [[Big O notation|&amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt;]] time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm&amp;lt;ref name=brandes/&amp;gt; which takes [[Big O notation|&amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt;]] time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&amp;lt;ref name=&amp;quot;brandes&amp;quot; /&amp;gt;&lt;br /&gt;
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From a calculation aspect, both betweenness and closeness centralities of all vertices in a graph involve calculating the shortest paths between all pairs of vertices on a graph, which requires &amp;lt;math&amp;gt;O(V^3)&amp;lt;/math&amp;gt; time with the Floyd–Warshall algorithm. However, on sparse graphs, Johnson's algorithm may be more efficient, taking &amp;lt;math&amp;gt;O(V^2 \log V + V E)&amp;lt;/math&amp;gt; time. In the case of unweighted graphs the calculations can be done with Brandes' algorithm which takes &amp;lt;math&amp;gt;O(V E)&amp;lt;/math&amp;gt; time. Normally, these algorithms assume that graphs are undirected and connected with the allowance of loops and multiple edges. When specifically dealing with network graphs, often graphs are without loops or multiple edges to maintain simple relationships (where edges represent connections between two people or vertices). In this case, using Brandes' algorithm will divide final centrality scores by 2 to account for each shortest path being counted twice.&lt;br /&gt;
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从计算的角度来看，图中所有顶点的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介和紧密中心性Betweenness and Closeness centralities&amp;lt;/font&amp;gt;'''都涉及到计算图中所有顶点对之间的最短路径，这就需要用 Floyd-Warshall 算法计算时间。然而，对于稀疏图，约翰逊算法的效率可能更高，采用 &amp;lt; math &amp;gt; o (v ^ 2 log v + v e) &amp;lt;/math &amp;gt; 时间。在不加权图的情况下，可以用 Brandes 的算法进行计算，该算法需要 &amp;lt; math &amp;gt; o (v e) &amp;lt;/math &amp;gt; 时间。一般情况下，这些算法假定图是无向的，并且连通图中允许有圈和多条边。当专门处理网络图时，图通常没有环或多条边来维持简单的关系(其中的边表示两个人或顶点之间的联系)。在这种情况下，使用 Brandes 的算法将最终的中心性分数除以2来计算每条被重复计算的最短路径。&lt;br /&gt;
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==Eigenvector centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Eigenvector centrality}}&lt;br /&gt;
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'''Eigenvector centrality''' (also called '''eigencentrality''') is a measure of the influence of a [[node (networking)|node]] in a [[network (mathematics)|network]]. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&amp;lt;ref&amp;gt;{{cite journal|title = The mathematics of networks|url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf|author = M. E. J. Newman|accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;Christian F. A. Negre, Uriel N. Morzan, Heidi P. Hendrickson, Rhitankar Pal, George P. Lisi, J. Patrick Loria, Ivan Rivalta, Junming Ho, Victor S. Batista. 2018 E12201--E12208&amp;quot;/&amp;gt; [[Google]]'s [[PageRank]] and the [[Katz centrality]] are variants of the eigenvector centrality.&amp;lt;ref name=&amp;quot;ams&amp;quot;&amp;gt;{{Cite web | url=http://www.ams.org/samplings/feature-column/fcarc-pagerank | title=American Mathematical Society}}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Eigenvector centrality (also called eigencentrality) is a measure of the influence of a node in a network. It assigns relative scores to all nodes in the network based on the concept that connections to high-scoring nodes contribute more to the score of the node in question than equal connections to low-scoring nodes.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征向量中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''(也称为特征中心性)是衡量网络中节点影响的一个指标。它将相对得分分配给网络中的所有节点，这是基于这样一个概念: 与得分较高的节点相比，与得分较低的节点相同的连接对所涉及的节点的得分贡献更大。&lt;br /&gt;
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=== Using the adjacency matrix to find eigenvector centrality ==&lt;br /&gt;
==使用'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''发现'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;特征中心性 Eigenvector centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the [[adjacency matrix]], i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
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For a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; number of vertices let &amp;lt;math&amp;gt;A = (a_{v,t})&amp;lt;/math&amp;gt; be the adjacency matrix, i.e. &amp;lt;math&amp;gt;a_{v,t} = 1&amp;lt;/math&amp;gt; if vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; is linked to vertex &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;a_{v,t} = 0&amp;lt;/math&amp;gt; otherwise. The relative centrality score of vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; can be defined as:&lt;br /&gt;
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对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 让 &amp;lt; math &amp;gt; a = (a { v，t }) &amp;lt;/math &amp;gt; 成为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 邻接矩阵The adjacency matrix&amp;lt;/font&amp;gt;'''，即。如果顶点 &amp;lt; math &amp;gt; &amp;gt; v &amp;lt;/math &amp;gt; 与 math &amp;gt; t &amp;lt;/math &amp;gt; 相连，而 &amp;lt; math &amp;gt; a { v，t } = 0 &amp;lt;/math &amp;gt; 否则。顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分可以定义为:&lt;br /&gt;
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:&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;x_v = \frac{1}{\lambda} \sum_{t \in M(v)}x_t = \frac{1}{\lambda} \sum_{t \in G} a_{v,t}x_t&amp;lt;/math&amp;gt;&lt;br /&gt;
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在 m (v)} x _ t = frac {1}{ lambda } sum { t in g } a { v，t } x _ t &amp;lt;/math &amp;gt; &lt;br /&gt;
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where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the [[eigenvector]] equation&lt;br /&gt;
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where &amp;lt;math&amp;gt;M(v)&amp;lt;/math&amp;gt; is a set of the neighbors of &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; is a constant. With a small rearrangement this can be rewritten in vector notation as the eigenvector equation&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; m (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; 和 &amp;lt; math &amp;gt; &amp;gt; lambda &amp;lt;/math &amp;gt; 的邻居集合。通过一个小的重新排列，这可以被重写成向量符号，作为特征向量方程&lt;br /&gt;
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:&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\mathbf{Ax} = {\lambda}\mathbf{x}&amp;lt;/math&amp;gt;&lt;br /&gt;
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[ math &amp;gt; mathbf { Ax } = { lambda } mathbf { x } &amp;lt;/math &amp;gt; &lt;br /&gt;
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In general, there will be many different [[eigenvalue]]s &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the [[Perron–Frobenius theorem]]. This greatest eigenvalue results in the desired centrality measure.&amp;lt;ref&amp;gt;{{cite journal  | author = M. E. J. Newman  | title = The mathematics of networks  | url = http://www-personal.umich.edu/~mejn/papers/palgrave.pdf  | accessdate = 2006-11-09}}&amp;lt;/ref&amp;gt; The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices ''n''. [[Power iteration]] is one of many [[eigenvalue algorithm]]s that may be used to find this dominant eigenvector.&amp;lt;ref name=&amp;quot;ams&amp;quot; /&amp;gt; Furthermore, this can be generalized so that the entries in ''A'' can be real numbers representing connection strengths, as in a [[stochastic matrix]].&lt;br /&gt;
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In general, there will be many different eigenvalues &amp;lt;math&amp;gt;\lambda&amp;lt;/math&amp;gt; for which a non-zero eigenvector solution exists. Since the entries in the adjacency matrix are non-negative, there is a unique largest eigenvalue, which is real and positive, by the Perron–Frobenius theorem. This greatest eigenvalue results in the desired centrality measure. The &amp;lt;math&amp;gt;v^{th}&amp;lt;/math&amp;gt; component of the related eigenvector then gives the relative centrality score of the vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; in the network. The eigenvector is only defined up to a common factor, so only the ratios of the centralities of the vertices are well defined. To define an absolute score one must normalise the eigenvector, e.g., such that the sum over all vertices is 1 or the total number of vertices n. Power iteration is one of many eigenvalue algorithms that may be used to find this dominant eigenvector. Furthermore, this can be generalized so that the entries in A can be real numbers representing connection strengths, as in a stochastic matrix.&lt;br /&gt;
&lt;br /&gt;
一般情况下，存在许多不同的特征值，对于这些特征值存在一个非零特征向量解。由于邻接矩阵中的条目是非负的，所以由 Perron-弗罗贝尼乌斯定理得出，它有一个实的和正的唯一最大特征值。由这个最大的特征值得出期望的中心性度量。相关特征向量的 &amp;lt; math &amp;gt; v ^ { th } &amp;lt;/math &amp;gt; 分量给出了网络中顶点 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的相对中心性评分。特征向量只定义了一个公共因子，所以只有顶点中心的比例是明确定义的。要定义一个绝对分数，必须对特征向量进行标准化，例如，使所有顶点的和为1或顶点的总数n。此外，这可以通用，使得 a 中的条目可以是表示连接强度的真实数字，就像'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 随机矩阵Stochastic matrix&amp;lt;/font&amp;gt;'''中一样。&lt;br /&gt;
&lt;br /&gt;
==Katz centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
{{main|Katz centrality}}&lt;br /&gt;
&lt;br /&gt;
'''Katz centrality'''&amp;lt;ref&amp;gt;Katz, L. 1953. A New Status Index Derived from Sociometric Index. Psychometrika, 39–43.&amp;lt;/ref&amp;gt; is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
Katz centrality is a generalization of degree centrality. Degree centrality measures the number of direct neighbors, and Katz centrality measures the number of all nodes that can be connected through a path, while the contributions of distant nodes are penalized. Mathematically, it is defined as&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''是度中心性的推广。度中心性度量的是直接邻居的数量，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''度量的是通过一条路径可以连接的所有节点的数量，而远处节点的贡献会受到'''&amp;lt;font color=&amp;quot;#32CD32&amp;quot;&amp;gt; '削弱（惩罚？）Penalized&amp;lt;/font&amp;gt;''。在数学上，它被定义为&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \sum_{k=1}^{\infin}\sum_{j=1}^N \alpha^k (A^k)_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[数学][数学]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; is an attenuation factor in  &amp;lt;math&amp;gt;(0,1)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; (0,1) &amp;lt;/math &amp;gt; 中的衰减因子。&lt;br /&gt;
&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
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Katz centrality can be viewed as a variant of eigenvector centrality. Another form of Katz centrality is&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 卡兹中心性Katz centrality&amp;lt;/font&amp;gt;'''可以看作是特征向量中心性的变体。Katz 中心性的另一种形式是&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j =1}^N a_{ij}(x_j+1).&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
(x _ j + 1) &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Compared to the expression of eigenvector centrality, &amp;lt;math&amp;gt;x_j&amp;lt;/math&amp;gt; is replaced by  &amp;lt;math&amp;gt;x_j+1.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
与特征向量中心性的表达式相比，&amp;lt; math &amp;gt; x _ j &amp;lt;/math &amp;gt; 被 &amp;lt; math &amp;gt; x _ j + 1所代替&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
It is shown that&amp;lt;ref&amp;gt;{{cite journal | last1 = Bonacich | first1 = P | year = 1991 | title = Simultaneous group and individual centralities | url = | journal = Social Networks | volume = 13 | issue = 2| pages = 155–168 | doi=10.1016/0378-8733(91)90018-o}}&amp;lt;/ref&amp;gt; the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
&lt;br /&gt;
It is shown that the principal eigenvector (associated with the largest eigenvalue of &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt;, the adjacency matrix) is the limit of Katz centrality as &amp;lt;math&amp;gt;\alpha&amp;lt;/math&amp;gt; approaches &amp;lt;math&amp;gt;\tfrac{1}{\lambda}&amp;lt;/math&amp;gt; from below.&lt;br /&gt;
&lt;br /&gt;
结果表明，主特征向量(与 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; ，邻接矩阵的最大特征值相关)是 Katz 中心性的极限，因为 &amp;lt; math &amp;gt; alpha &amp;lt;/math &amp;gt; 接近 &amp;lt; math &amp;gt; tfrac {1}{ lambda } &amp;lt;/math &amp;gt; 。&lt;br /&gt;
&lt;br /&gt;
== PageRank centrality ==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 网页分布中心性PageRank&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
{{main|PageRank}}'''[[PageRank]]''' satisfies the following equation&lt;br /&gt;
&lt;br /&gt;
PageRank satisfies the following equation&lt;br /&gt;
&lt;br /&gt;
PageRank满足下面的等式&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;x_i = \alpha \sum_{j } a_{ji}\frac{x_j}{L(j)} + \frac{1-\alpha}{N},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
1-alpha { n } ，&amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
where&lt;br /&gt;
&lt;br /&gt;
其中&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;L(j) = \sum_{i} a_{ji}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[ math &amp;gt; l (j) = sum { i } a { ji } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&amp;lt;ref&amp;gt;[http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf How does Google rank webpages?] {{webarchive | url= https://web.archive.org/web/20120131083328/http://scenic.princeton.edu/network20q/lectures/Q3_notes.pdf |date=January 31, 2012 }} 20Q: About Networked Life&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
is the number of neighbors of node &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (or number of outbound links in a directed graph). Compared to eigenvector centrality and Katz centrality, one major difference is the scaling factor &amp;lt;math&amp;gt;L(j)&amp;lt;/math&amp;gt;. Another difference between PageRank and eigenvector centrality is that the PageRank vector is a left hand eigenvector (note the factor &amp;lt;math&amp;gt;a_{ji}&amp;lt;/math&amp;gt; has indices reversed).&lt;br /&gt;
&lt;br /&gt;
是节点 &amp;lt; math &amp;gt; j &amp;lt;/math &amp;gt; (或有向图中出站链接的数量)的邻居数量。与特征向量中心性和 Katz 中心性相比，尺度因子 &amp;lt; math &amp;gt; l (j) &amp;lt;/math &amp;gt; 是一个主要的区别。PageRank 和特征向量中心性的另一个区别是 PageRank 向量是一个左手特征向量(注意因子 &amp;lt; math &amp;gt; a _ { ji } &amp;lt;/math &amp;gt; 具有相反的索引)。&lt;br /&gt;
&lt;br /&gt;
==Percolation centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&amp;lt;ref name=&amp;quot;piraveenan2013&amp;quot;&amp;gt;{{cite journal |last1 = Piraveenan |first1 = M. |last2 = Prokopenko |first2 = M.|last3 = Hossain|first3 = L. |year=2013| title = Percolation Centrality: Quantifying Graph-Theoretic Impact of Nodes during Percolation in Networks | journal = PLOS One | volume=8 | issue=1 | doi=10.1371/journal.pone.0053095 | pages=e53095 | pmid=23349699 | pmc=3551907| bibcode=2013PLoSO...853095P }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
A slew of centrality measures exist to determine the ‘importance’ of a single node in a complex network. However, these measures quantify the importance of a node in purely topological terms, and the value of the node does not depend on the ‘state’ of the node in any way. It remains constant regardless of network dynamics. This is true even for the weighted betweenness measures. However, a node may very well be centrally located in terms of betweenness centrality or another centrality measure, but may not be ‘centrally’ located in the context of a network in which there is percolation. Percolation of a ‘contagion’ occurs in complex networks in a number of scenarios. For example, viral or bacterial infection can spread over social networks of people, known as contact networks. The spread of disease can also be considered at a higher level of abstraction, by contemplating a network of towns or population centres, connected by road, rail or air links. Computer viruses can spread over computer networks. Rumours or news about business offers and deals can also spread via social networks of people. In all of these scenarios, a ‘contagion’ spreads over the links of a complex network, altering the ‘states’ of the nodes as it spreads, either recoverably or otherwise. For example, in an epidemiological scenario, individuals go from ‘susceptible’ to ‘infected’ state as the infection spreads. The states the individual nodes can take in the above examples could be binary (such as received/not received a piece of news), discrete (susceptible/infected/recovered), or even continuous (such as the proportion of infected people in a town), as the contagion spreads. The common feature in all these scenarios is that the spread of contagion results in the change of node states in networks. Percolation centrality (PC) was proposed with this in mind, which specifically measures the importance of nodes in terms of aiding the percolation through the network. This measure was proposed by Piraveenan et al.&lt;br /&gt;
&lt;br /&gt;
在复杂网络中，存在大量的中心性度量来确定单个节点的“重要性”。然而，这些度量单纯从拓扑学的角度来量化节点的重要性，节点的值并不以任何方式依赖于节点的状态。不管网络动态如何，它都保持不变。即使对于加权的两者之间的度量也是如此。然而，一个节点可能很好地位于'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''或其他中心性度量的中心位置，但可能不是位于有过滤的网络的上下文中的中心位置。在许多情况下，复杂网络中都会出现“传染”现象。例如，病毒或细菌感染可以通过人们的社交网络传播，也就是所谓的接触网络。还可以在更高的抽象层次上考虑疾病的传播问题，设想通过公路、铁路或空中连接起来的城镇或人口中心网络。计算机病毒可以通过计算机网络传播。关于商业活动和交易的谣言或新闻也可以通过人们的社交网络传播。在所有这些情况下，一种“传染病”在一个复杂网络的链接上传播，随着它的传播，无论是可恢复的还是不可恢复的，都会改变节点的“状态”。例如，在流行病学方案中，随着感染扩散，个人从”易感”状态转变为”受感染”状态。在上面的例子中，随着传染的扩散，每个节点可以采取的状态可以是二进制的(例如接收/没有接收到一条新闻)、离散的(易感/受感染/康复) ，甚至是连续的(例如一个城镇中受感染的人的比例) 。这些情景的共同特点是，传染的扩散导致网络中节点状态的改变。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''（PC)就是基于这个思想而提出的，它特别地衡量了节点在协助网络渗滤方面的重要性。这项措施是由 piraveanan 等人提出的。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
'''Percolation centrality''' is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
&lt;br /&gt;
Percolation centrality is defined for a given node, at a given time, as the proportion of ‘percolated paths’ that go through that node. A ‘percolated path’ is a shortest path between a pair of nodes, where the source node is percolated (e.g., infected). The target node can be percolated or non-percolated, or in a partially percolated state.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''定义为在给定时间内一个给定节点的过滤路径的比例。“渗滤路径”是一对节点之间的最短路径，其中源节点被渗滤(例如，被感染)。目标节点可以是过滤的或非过滤的，或处于部分过滤状态。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
:&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;PC^t(v)= \frac{1}{N-2}\sum_{s \neq v \neq r}\frac{\sigma_{sr}(v)}{\sigma_{sr}}\frac{{x^t}_s}{{\sum {[{x^t}_i}]}-{x^t}_v}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; PC ^ t (v) = frac {1}{ N-2} sum { s neq v neq r } frac { sigma { sr }(v)}{ sigma { sr }} frac { x ^ t }{ sum {[{ x ^ t } i }}}]}}-{ x ^ t }{ v } &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;\sigma_{sr}&amp;lt;/math&amp;gt; is total number of shortest paths from node &amp;lt;math&amp;gt;s&amp;lt;/math&amp;gt; to node &amp;lt;math&amp;gt;r&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;\sigma_{sr}(v)&amp;lt;/math&amp;gt; is the number of those paths that pass through &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt;. The percolation state of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; is denoted by &amp;lt;math&amp;gt;{x^t}_i&amp;lt;/math&amp;gt; and two special cases are when &amp;lt;math&amp;gt;{x^t}_i=0&amp;lt;/math&amp;gt; which indicates a non-percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt; whereas when &amp;lt;math&amp;gt;{x^t}_i=1&amp;lt;/math&amp;gt; which indicates a fully percolated state at time &amp;lt;math&amp;gt;t&amp;lt;/math&amp;gt;. The values in between indicate partially percolated states ( e.g., in a network of townships, this would be the percentage of people infected in that town).&lt;br /&gt;
&lt;br /&gt;
其中 &amp;lt; math &amp;gt; σ { sr } &amp;lt;/math &amp;gt; 是从节点 &amp;lt; math &amp;gt; s &amp;lt;/math &amp;gt; 到节点 &amp;lt; math &amp;gt; r &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; sigma { sr }(v) &amp;lt;/math &amp;gt; 是通过 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 的路径的总数。在时间 &amp;lt; math &amp;gt; t &amp;lt;/math &amp;gt; 时，节点的过滤状态用 &amp;lt; math &amp;gt; { x ^ t } _ i &amp;lt;/math &amp;gt; 表示，两个特殊情况是当 &amp;lt; math &amp;gt; { x ^ t } _ i = 0 &amp;lt;/math &amp;gt; 表示在时间上是非过滤状态，而当 &amp;lt; math &amp;gt; &amp;lt; x ^ t &amp;lt;/math &amp;gt; i = 1 &amp;lt;/math &amp;gt; 表示在时间上是完全过滤状态。两者之间的值表示部分过滤状态(例如，在一个城镇网络中，这是该城镇感染者的百分比)。&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in [[Big O notation|&amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt;]] time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is [[Big O notation|&amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;]].&lt;br /&gt;
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The attached weights to the percolation paths depend on the percolation levels assigned to the source nodes, based on the premise that the higher the percolation level of a source node is, the more important are the paths that originate from that node. Nodes which lie on shortest paths originating from highly percolated nodes are therefore potentially more important to the percolation. The definition of PC may also be extended to include target node weights as well. Percolation centrality calculations run in &amp;lt;math&amp;gt;O(NM)&amp;lt;/math&amp;gt; time with an efficient implementation adopted from Brandes' fast algorithm and if the calculation needs to consider target nodes weights, the worst case time is &amp;lt;math&amp;gt;O(N^3)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
渗流路径的权重取决于分配给源节点的渗流水平，前提是源节点的渗流水平越高，源节点的路径就越重要。因此，位于源自高渗滤节点的最短路径上的节点可能对渗滤更为重要。PC 的定义也可以扩展到包括目标节点的权重。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 渗滤中心性Percolation centrality&amp;lt;/font&amp;gt;'''计算运行在 &amp;lt; math &amp;gt; o (NM) &amp;lt;/math &amp;gt; 时间，采用了 Brandes 快速算法的有效实现，如果计算需要考虑目标节点的权重，最坏情况下时间为 &amp;lt; math &amp;gt; o (n ^ 3) &amp;lt;/math &amp;gt; 。&lt;br /&gt;
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==Cross-clique centrality==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 交叉团中心性Cross-clique centrality&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
'''Cross-clique centrality''' of a single node in a complex graph determines the connectivity of a node to different [[clique (graph theory)|clique]]s. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in &amp;lt;ref name=&amp;quot;xssworms&amp;quot;&amp;gt;{{cite journal |last1 = Faghani|first1 = Mohamamd Reza| year=2013| title = A Study of XSS Worm Propagation and Detection Mechanisms in Online Social Networks | journal = IEEE Transactions on Information Forensics and Security|volume = 8|issue = 11|pages = 1815–1826|doi = 10.1109/TIFS.2013.2280884}}&amp;lt;/ref&amp;gt; but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
&lt;br /&gt;
Cross-clique centrality of a single node in a complex graph determines the connectivity of a node to different cliques. A node with high cross-clique connectivity facilitates the propagation of information or disease in a graph. Cliques are subgraphs in which every node is connected to every other node in the clique. The cross-clique connectivity of a node &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; for a given graph &amp;lt;math&amp;gt;G:=(V,E)&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;|V|&amp;lt;/math&amp;gt; vertices and &amp;lt;math&amp;gt;|E|&amp;lt;/math&amp;gt; edges, is defined as &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; where &amp;lt;math&amp;gt;X(v)&amp;lt;/math&amp;gt; is the number of cliques to which vertex &amp;lt;math&amp;gt;v&amp;lt;/math&amp;gt; belongs.  This measure was used in  but was first proposed by Everett and Borgatti in 1998 where they called it clique-overlap centrality.&lt;br /&gt;
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复杂图中单个节点的跨团中心性决定了一个节点与不同团的连通性。具有高度跨团连通性的节点有利于信息或疾病在图中的传播。团是一种'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 子图Subgraphs&amp;lt;/font&amp;gt;'''，团中的每个节点都与团中的其他节点相连。对于一个给定的图 g: = (v，e) &amp;lt;/math &amp;gt; 与 &amp;lt; math &amp;gt; | v | &amp;lt;/math &amp;gt; 顶点和 &amp;lt; math &amp;gt; | e | &amp;lt;/math &amp;gt; 边的交叉团连通性，定义为 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; x (v) &amp;lt;/math &amp;gt; 其中 &amp;lt; math &amp;gt; x (v) &amp;lt;/math &amp;gt; 是 &amp;lt; math &amp;gt; v &amp;lt;/math &amp;gt; 所属的顶点团数。这个测度应用日久，但是在1998年由 Everett 和 Borgatti 首次提出，他们称之为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 派系重叠中心性Clique-overlap centrality&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
&lt;br /&gt;
==Freeman centralization==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 弗里曼中心度Freeman centralization&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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The '''centralization''' of any network is a measure of how central its most central node is in relation to how central all the other nodes are.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;&amp;gt;{{citation | journal = Social Networks | last1 = Freeman | first1 = Linton C. | year = 1979 | volume = 1 | issue = 3 | pages = 215–239 | title = centrality in social networks: Conceptual clarification | url = http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | doi = 10.1016/0378-8733(78)90021-7 | citeseerx = 10.1.1.227.9549 | access-date = 2014-07-31 | archive-url = https://web.archive.org/web/20160222033108/http://leonidzhukov.ru/hse/2013/socialnetworks/papers/freeman79-centrality.pdf | archive-date = 2016-02-22 | url-status = dead }}&amp;lt;/ref&amp;gt; Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
&lt;br /&gt;
The centralization of any network is a measure of how central its most central node is in relation to how central all the other nodes are. Centralization measures then (a) calculate the sum in differences in centrality between the most central node in a network and all other nodes; and (b) divide this quantity by the theoretically largest such sum of differences in any network of the same size.  Thus, every centrality measure can have its own centralization measure.  Defined formally, if &amp;lt;math&amp;gt;C_x(p_i)&amp;lt;/math&amp;gt; is any centrality measure of point &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;C_x(p_*)&amp;lt;/math&amp;gt; is the largest such measure in the network, and if:&lt;br /&gt;
&lt;br /&gt;
任何网络的集中度都是衡量其最核心的节点相对于其他所有节点的集聚程度的标准。集中度的度量方法是: (a)计算网络中最中心的节点与所有其他节点之间的中心性差异之和; (b)将这个数量除以理论上相同规模的任何网络中这种差异之和的最大值。因此，每个中心性度量都可以有自己的集中性度量。正式定义，如果 &amp;lt; math &amp;gt; c _ x (p _ i) &amp;lt;/math &amp;gt; 是点 &amp;lt; math &amp;gt; i &amp;lt;/math &amp;gt; 的中心性度量，如果 &amp;lt; math &amp;gt; c _ x (p _ *) &amp;lt;/math &amp;gt; 是网络中最大的中心性度量，如果:&lt;br /&gt;
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:&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt; math &amp;gt; max sum { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i) &amp;lt;/math &amp;gt; &lt;br /&gt;
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is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&amp;lt;ref name=&amp;quot;Freeman1979&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
is the largest sum of differences in point centrality &amp;lt;math&amp;gt;C_x&amp;lt;/math&amp;gt; for any graph with the same number of nodes, then the centralization of the network is:&lt;br /&gt;
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对于任何具有相同节点数的图来说，点中心性的最大差异是:&lt;br /&gt;
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:&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;C_x=\frac{\sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}{\max \sum_{i=1}^{N} C_x(p_*)-C_x(p_i)}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt; math &amp;gt; c _ x = frac { sum _ { i = 1} ^ { n } c _ x (p _ *)-c _ x (p _ i)}{ max sum _ { i = 1 ^ { n } c _ x (p _ *)-c _ x (p _ i)} . &amp;lt;/math &amp;gt;&lt;br /&gt;
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== Dissimilarity based centrality measures ==&lt;br /&gt;
==基于相异性的中心性度量==&lt;br /&gt;
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[[File:Srep17095-f1.jpg|thumbnail|In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.]]&lt;br /&gt;
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In the illustrated network, green and red nodes are the most dissimilar because they do not share neighbors between them. So, the green one contributes more to the centrality of the red one than the gray ones, because the red one can access to the blue ones only through the green, and the gray nodes are redundant for the red one, because it can access directly to each gray node without any intermediary.&lt;br /&gt;
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在图示的网络中，绿色节点和红色节点最不相似，因为它们之间不共享相邻节点。因此，绿色的节点比灰色的节点对中心性的贡献更大，因为红色的节点只能通过绿色访问蓝色的节点，而灰色的节点对于红色的节点是多余的，因为它可以直接访问每个灰色的节点，而不需要任何中介。&lt;br /&gt;
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In order to obtain better results in the ranking of the nodes of a given network,  in &amp;lt;ref&amp;gt;{{Cite journal|title = Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|journal = Scientific Reports|date = 2015-11-25|pmc = 4658528|pmid = 26603652|volume = 5|doi = 10.1038/srep17095|first = A. J.|last = Alvarez-Socorro|first2 = G. C.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz|pages=17095|bibcode = 2015NatSR...517095A}}&amp;lt;/ref&amp;gt; are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with [[eigenvector centrality]], calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
&lt;br /&gt;
In order to obtain better results in the ranking of the nodes of a given network,  in  are used dissimilarity measures (specific to the theory of classification and data mining) to enrich the centrality measures in complex networks. This is illustrated with eigenvector centrality, calculating the centrality of each node through the solution of the eigenvalue problem&lt;br /&gt;
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为了在给定网络节点的排序中获得更好的结果，在复杂网络中使用了相异性度量(特定于分类和数据挖掘理论)来丰富中心性度量。特征向量中心性通过求解特征值问题来计算每个节点的中心性&lt;br /&gt;
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:&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;W\mathbf{c}=\lambda \mathbf{c}&amp;lt;/math&amp;gt;&lt;br /&gt;
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数学，数学&lt;br /&gt;
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where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary [[Matrix similarity|dissimilarity]] matrix, defined through a dissimilitary measure, e.g., [[Jaccard index|Jaccard]] dissimilarity given by&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;W_{ij}=A_{ij}D_{ij}&amp;lt;/math&amp;gt; (coordinate-to-coordinate product) and &amp;lt;math&amp;gt;D_{ij}&amp;lt;/math&amp;gt; is an arbitrary dissimilarity matrix, defined through a dissimilitary measure, e.g., Jaccard dissimilarity given by&lt;br /&gt;
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这里 &amp;lt; math &amp;gt; w { ij } = a { ij } d { ij } &amp;lt;/math &amp;gt; (coordinate-to-coordinate product)和 &amp;lt; math &amp;gt; d { ij } &amp;lt;/math &amp;gt; 是一个任意的不相似矩阵，通过一个双重军事度量来定义，例如，Jaccard 由&lt;br /&gt;
&lt;br /&gt;
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:&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;D_{ij}=1-\dfrac{|V^{+}(i)\cap V^{+}(j)|}{|V^{+}(i)\cup V^{+}(j)|}&amp;lt;/math&amp;gt;&lt;br /&gt;
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1-dfrac { | v ^ { + }(i) cap v ^ { + }(j) | }{ | v ^ { + }(i) cup v ^ { + }(j) | } &amp;lt;/math &amp;gt; &lt;br /&gt;
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Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
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Where this measure permits us to quantify the topological contribution (which is why is called contribution centrality) of each node to the centrality of a given node, having more weight/relevance those nodes with greater dissimilarity, since these allow to the given node access to nodes that which themselves can not access directly.&lt;br /&gt;
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这种度量允许我们量化每个节点对给定节点中心性的拓扑贡献(这就是为什么我们称之为贡献中心性) ，对那些相异性较大的节点有更多的权重/相关性，因为这些节点允许给定的节点访问那些它们自己不能直接访问的节点。&lt;br /&gt;
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Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the [[Perron–Frobenius theorem]] to ensure that the above problem has a unique solution for ''λ'' = ''λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt;'' with '''c''' non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
&lt;br /&gt;
Is noteworthy that &amp;lt;math&amp;gt;W&amp;lt;/math&amp;gt; is non-negative because &amp;lt;math&amp;gt;A&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; are non-negative matrices, so we can use the Perron–Frobenius theorem to ensure that the above problem has a unique solution for λ = λ&amp;lt;sub&amp;gt;max&amp;lt;/sub&amp;gt; with c non-negative, allowing us to infer the centrality of each node in the network. Therefore, the centrality of the i-th node is&lt;br /&gt;
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值得注意的是，&amp;lt; math &amp;gt; w &amp;lt;/math &amp;gt; 是非负的，因为 &amp;lt; math &amp;gt; a &amp;lt;/math &amp;gt; 和 &amp;lt; math &amp;gt; d &amp;lt;/math &amp;gt; 都是非负矩阵，所以我们可以使用 Perron 弗罗贝尼乌斯定理来确保上述问题对于 c 非负的 = &amp;lt; sub &amp;gt; max &amp;lt;/sub &amp;gt; 有唯一的解，这样我们就可以推断出网络中每个节点的中心性。因此，i-th 节点的中心性为&lt;br /&gt;
&lt;br /&gt;
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:&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;c_i=\dfrac{1}{n}\sum_{j=1}^{n}W_{ij}c_{j}, \,\,\,\,\,\, j=1,\cdots,n&amp;lt;/math&amp;gt;&lt;br /&gt;
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1{ n } sum { j = 1} ^ { n } w { ij } c { j } ，，，，，j = 1，cdots，n &amp;lt;/math &amp;gt; &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
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where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in &amp;lt;ref&amp;gt;{{Cite web|url = http://www.nature.com/article-assets/npg/srep/2015/151125/srep17095/extref/srep17095-s1.pdf|title = Supplementary Information for Eigencentrality based on dissimilarity measures reveals central nodes in complex networks|date = |website = |publisher = Nature Publishing Group|last = Alvarez-Socorro|first = A.J.|last2 = Herrera-Almarza|first3 = L. A.|last3 = González-Díaz}}&amp;lt;/ref&amp;gt; obtaining improved results in the studied cases.&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; is the number of the nodes in the network. Several dissimilarity measures and networks were tested in  obtaining improved results in the studied cases.&lt;br /&gt;
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其中 &amp;lt; math &amp;gt; n &amp;lt;/math &amp;gt; 是网络中的节点数。几个不同的措施和网络进行了测试，以获得在研究案例的改善的结果。&lt;br /&gt;
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==Extensions==&lt;br /&gt;
==扩展==&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality&amp;lt;ref&amp;gt;{{cite journal | last1 = Braha | first1 = D. | last2 = Bar-Yam | first2 = Y. | year = 2006 | title = From Centrality to Temporary Fame: Dynamic Centrality in Complex Networks | url = | journal = Complexity | volume = 12 | issue = 2| pages = 59–63 | doi=10.1002/cplx.20156| arxiv = physics/0611295 | bibcode = 2006Cmplx..12b..59B }}&amp;lt;/ref&amp;gt; in the context of time-dependent and temporal networks.&amp;lt;ref&amp;gt;{{cite journal | last1 = Hill | first1 = S.A. | last2 = Braha | first2 = D. | year = 2010 | title = Dynamic Model of Time-Dependent Complex Networks | url = | journal = Physical Review E | volume = 82 | issue = 4| page = 046105 | doi=10.1103/physreve.82.046105| pmid = 21230343 | arxiv = 0901.4407 | bibcode = 2010PhRvE..82d6105H }}&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Gross, T. and Sayama, H. (Eds.). 2009. ''Adaptive Networks: Theory, Models and Applications.'' Springer.&amp;lt;/ref&amp;gt;&amp;lt;ref&amp;gt;Holme, P. and Saramäki, J. 2013. ''Temporal Networks.'' Springer.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Empirical and theoretical research have extended the concept of centrality in the context of static networks to dynamic centrality in the context of time-dependent and temporal networks.&lt;br /&gt;
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经验和理论研究已经将静态网络中的中心性概念扩展到时间依赖网络和时间网络中的动态中心性。&lt;br /&gt;
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For generalizations to weighted networks, see Opsahl et al. (2010).&amp;lt;ref&amp;gt;{{cite journal | last1 = Opsahl | first1 = Tore | last2 = Agneessens | first2 = Filip | last3 = Skvoretz | first3 = John | title = Node centrality in weighted networks: Generalizing degree and shortest paths | doi = 10.1016/j.socnet.2010.03.006 | year = 2010 | pages = 245–251 | volume = 32 | journal = Social Networks | url = http://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | issue = 3 | access-date = 2010-04-23 | archive-url = https://web.archive.org/web/20180226080331/https://toreopsahl.com/2010/04/21/article-node-centrality-in-weighted-networks-generalizing-degree-and-shortest-paths/ | archive-date = 2018-02-26 | url-status = dead }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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For generalizations to weighted networks, see Opsahl et al. (2010).&lt;br /&gt;
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对加权网络的推广，见 Opsahl 等人。(2010).&lt;br /&gt;
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The concept of centrality was extended to a group level as well. For example, '''group betweenness''' centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&amp;lt;ref name=&amp;quot;group1&amp;quot;&amp;gt;Everett, M. G. and Borgatti, S. P. (2005). Extending centrality. In P. J. Carrington, J. Scott and S. Wasserman (Eds.), ''Models and methods in social network analysis'' (pp. 57–76). New York: Cambridge University Press.&amp;lt;/ref&amp;gt;&amp;lt;ref name=&amp;quot;group2&amp;quot;&amp;gt;Puzis, R., Yagil, D., Elovici, Y., Braha, D. (2009).[http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf Collaborative attack on Internet users’ anonymity] {{Webarchive|url=https://web.archive.org/web/20131207133417/http://necsi.edu/affiliates/braha/Internet_Research_Anonimity.pdf |date=2013-12-07 }}, ''Internet Research'' '''19'''(1)&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The concept of centrality was extended to a group level as well. For example, group betweenness centrality shows the proportion of geodesics connecting pairs of non-group members that pass through the group.&lt;br /&gt;
&lt;br /&gt;
中心性的概念也扩展到了群体层次。例如，组间的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 中介中心性Betweenness centrality&amp;lt;/font&amp;gt;'''显示了连接穿过组的成对非组成员的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt; 测地线Geodesics &amp;lt;/font&amp;gt;'''的比例。&lt;br /&gt;
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==See also==&lt;br /&gt;
==又及==&lt;br /&gt;
* [[Alpha centrality]]&lt;br /&gt;
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* [[Core–periphery structure]]&lt;br /&gt;
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* [[Distance (graph theory)|Distance in graphs]]&lt;br /&gt;
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*阿尔法中心性&lt;br /&gt;
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*核心—外围结构&lt;br /&gt;
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*距离（图理论）图中的距离&lt;br /&gt;
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==Notes and references==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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==Further reading==&lt;br /&gt;
拓展阅读&lt;br /&gt;
* Koschützki, D.; Lehmann, K. A.; Peeters, L.; Richter, S.; Tenfelde-Podehl, D. and Zlotowski, O. (2005) Centrality Indices. In Brandes, U. and Erlebach, T. (Eds.)  ''Network Analysis: Methodological Foundations'', pp.&amp;amp;nbsp;16–61, LNCS 3418, Springer-Verlag.&lt;br /&gt;
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[[Category:Graph theory]]&lt;br /&gt;
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Category:Graph theory&lt;br /&gt;
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分类: 图论&lt;br /&gt;
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[[Category:Graph algorithms]]&lt;br /&gt;
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Category:Graph algorithms&lt;br /&gt;
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分类: 图形算法&lt;br /&gt;
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[[Category:Algebraic graph theory]]&lt;br /&gt;
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Category:Algebraic graph theory&lt;br /&gt;
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分类: 代数图论&lt;br /&gt;
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[[Category:Networks]]&lt;br /&gt;
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Category:Networks&lt;br /&gt;
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分类: 网络&lt;br /&gt;
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[[Category:Network analysis]]&lt;br /&gt;
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Category:Network analysis&lt;br /&gt;
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分类: 网络分析&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Centrality]]. Its edit history can be viewed at [[网络中心性/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17795</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17795"/>
		<updated>2020-11-03T07:27:29Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Degree correlation 度相关 */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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枢纽的涌现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
图4：基于Barabasi-Albert模型的网络增长（&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;）]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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网络起始于由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点组成的初始联通网络。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被链接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;个现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与现有节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;相连的概率&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;为&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;：&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度，求和则是针对所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;进行的。（分母的数值是网络边数的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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网络中枢纽的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，涌现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大互联网枢纽的8年后，Facebook出现了，并于2011年成为了全球最大的互联网枢纽。因此，在实际网络中，枢纽的增长和规模也取决于各种各样的其他属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽有诸多属性：&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络路径长度===&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽越多，节点之间的距离就越短。在无标度网络中，枢纽是连接小度节点的桥梁。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt;由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径长度的差异可能并不明显，但是在大型随机网络和无标度网络中，路径长度的差异是显著的。&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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无标度网络中的平均路径长度:&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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===Aging of hubs (nodes) 枢纽（节点）的老化===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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当旧的枢纽被隐藏在网络中时，这种现象便在真实网络中出现。这种现象导致了网络演化和拓扑结构的变化。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; 老化现象的例子可参照 Facebook 超越了网络中最大的枢纽 Google (自2000年以来最大的节点)。&lt;br /&gt;
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===Robustness and Attack Tolerance 鲁棒性和抗毁性===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&lt;br /&gt;
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当节点发生随机故障或特定攻击时，枢纽是网络的重要构件。当网络中的节点发生随机故障时，枢纽影响网络的鲁棒性。&lt;br /&gt;
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The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除枢纽的几率很小。而去除小度节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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在对枢纽进行特定的攻击时，网络的完整性会相对较快地被破坏。由于小度节点大量的链接到枢纽，因此对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时头号玩家（枢纽）的破产导致了整个系统的持续崩溃。&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt;另一方面，去除恐怖主义网络中的枢纽可能会产生积极的影响，特定节点的消失可能会摧毁整个恐怖组织。网络的抗毁性可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只链接到相同度值的节点。节点之间的这种链接决定了网络的拓扑结构，从而影响了上文所讨论的网络鲁棒性。如果枢纽之间的链接数量与随机模式下的期望值相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽倾向于相互连接，同时避免链接到小度节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;同配网络 Assortative Network&amp;lt;/font&amp;gt;'''。这种网络的抗毁性相对较强，因为枢纽形成了一个核心团体，这对枢纽的移除来说是更加冗余的。如果枢纽避免相互链接，同时链接到小度节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;异配网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这种网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽，可能会破坏或摧毁整个网络。&lt;br /&gt;
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===Spreading phenomenon 传播现象===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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枢纽还负责要素在网络上的有效传播。在疾病传播或信息流动的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。如H1H1流行病预测等数学模型，可以基于人类流动网络，传染性，或人与人之间的社会互动，让我们预测疾病的传播。在消灭疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的链接。在枢纽被感染后，它将将疾病传播到它所链接的节点。因此，选择性免疫那些枢纽可能是消灭传播性疾病的成本效率最高的策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17793</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17793"/>
		<updated>2020-11-03T07:25:50Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Robustness and Attack Tolerance 鲁棒性和抗毁性 */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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枢纽的涌现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
图4：基于Barabasi-Albert模型的网络增长（&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;）]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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网络起始于由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点组成的初始联通网络。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被链接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;个现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与现有节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;相连的概率&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;为&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;：&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度，求和则是针对所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;进行的。（分母的数值是网络边数的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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网络中枢纽的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，涌现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大互联网枢纽的8年后，Facebook出现了，并于2011年成为了全球最大的互联网枢纽。因此，在实际网络中，枢纽的增长和规模也取决于各种各样的其他属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽有诸多属性：&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络路径长度===&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽越多，节点之间的距离就越短。在无标度网络中，枢纽是连接小度节点的桥梁。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt;由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径长度的差异可能并不明显，但是在大型随机网络和无标度网络中，路径长度的差异是显著的。&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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无标度网络中的平均路径长度:&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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===Aging of hubs (nodes) 枢纽（节点）的老化===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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当旧的枢纽被隐藏在网络中时，这种现象便在真实网络中出现。这种现象导致了网络演化和拓扑结构的变化。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; 老化现象的例子可参照 Facebook 超越了网络中最大的枢纽 Google (自2000年以来最大的节点)。&lt;br /&gt;
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===Robustness and Attack Tolerance 鲁棒性和抗毁性===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&lt;br /&gt;
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当节点发生随机故障或特定攻击时，枢纽是网络的重要构件。当网络中的节点发生随机故障时，枢纽影响网络的鲁棒性。&lt;br /&gt;
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The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除枢纽的几率很小。而去除小度节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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在对枢纽进行特定的攻击时，网络的完整性会相对较快地被破坏。由于小度节点大量的链接到枢纽，因此对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时头号玩家（枢纽）的破产导致了整个系统的持续崩溃。&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt;另一方面，去除恐怖主义网络中的枢纽可能会产生积极的影响，特定节点的消失可能会摧毁整个恐怖组织。网络的抗毁性可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种链接决定了网络的拓扑结构，从而影响了上文所讨论的网络鲁棒性。如果枢纽之间的链接数量与随机模式下的期望值相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽倾向于相互连接，同时避免链接到小度节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;同配网络 Assortative Network&amp;lt;/font&amp;gt;'''。这种网络的抗毁性相对较强，因为枢纽形成了一个核心团体，这对枢纽的移除来说是更加冗余的。如果枢纽避免相互链接，同时链接到小度节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;异配网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这种网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽，可能会破坏或摧毁整个网络。&lt;br /&gt;
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===Spreading phenomenon 传播现象===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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枢纽还负责要素在网络上的有效传播。在疾病传播或信息流动的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。如H1H1流行病预测等数学模型，可以基于人类流动网络，传染性，或人与人之间的社会互动，让我们预测疾病的传播。在消灭疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的链接。在枢纽被感染后，它将将疾病传播到它所链接的节点。因此，选择性免疫那些枢纽可能是消灭传播性疾病的成本效率最高的策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17792</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17792"/>
		<updated>2020-11-03T07:25:21Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Robustness and Attack Tolerance 鲁棒性和抗毁性 */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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枢纽的涌现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
图4：基于Barabasi-Albert模型的网络增长（&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;）]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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网络起始于由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点组成的初始联通网络。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被链接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;个现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与现有节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;相连的概率&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;为&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;：&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度，求和则是针对所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;进行的。（分母的数值是网络边数的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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网络中枢纽的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，涌现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大互联网枢纽的8年后，Facebook出现了，并于2011年成为了全球最大的互联网枢纽。因此，在实际网络中，枢纽的增长和规模也取决于各种各样的其他属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
&lt;br /&gt;
There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽有诸多属性：&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络路径长度===&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽越多，节点之间的距离就越短。在无标度网络中，枢纽是连接小度节点的桥梁。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt;由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径长度的差异可能并不明显，但是在大型随机网络和无标度网络中，路径长度的差异是显著的。&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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无标度网络中的平均路径长度:&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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===Aging of hubs (nodes) 枢纽（节点）的老化===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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当旧的枢纽被隐藏在网络中时，这种现象便在真实网络中出现。这种现象导致了网络演化和拓扑结构的变化。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; 老化现象的例子可参照 Facebook 超越了网络中最大的枢纽 Google (自2000年以来最大的节点)。&lt;br /&gt;
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===Robustness and Attack Tolerance 鲁棒性和抗毁性===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&lt;br /&gt;
当节点发生随机故障或特定攻击时，枢纽是网络的重要构件。当网络中的节点发生随机故障时，枢纽影响网络的鲁棒性。&lt;br /&gt;
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The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除枢纽的几率很小。而去除小度节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
在对枢纽进行特定的攻击时，网络的完整性会相对较快地被破坏。由于小度节点大量的链接到枢纽，因此对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时头号玩家（枢纽）的破产导致了整个系统的持续崩溃。&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt;另一方面，去除恐怖主义网络中的枢纽可能会产生积极的影响，特定节点的消失可能会摧毁整个恐怖组织。网络的抗毁性可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
&lt;br /&gt;
=== Degree correlation 度相关===&lt;br /&gt;
&lt;br /&gt;
The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
&lt;br /&gt;
The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种链接决定了网络的拓扑结构，从而影响了上文所讨论的网络鲁棒性。如果枢纽之间的链接数量与随机模式下的期望值相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽倾向于相互连接，同时避免链接到小度节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;同配网络 Assortative Network&amp;lt;/font&amp;gt;'''。这种网络的抗毁性相对较强，因为枢纽形成了一个核心团体，这对枢纽的移除来说是更加冗余的。如果枢纽避免相互链接，同时链接到小度节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;异配网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这种网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽，可能会破坏或摧毁整个网络。&lt;br /&gt;
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===Spreading phenomenon 传播现象===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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枢纽还负责要素在网络上的有效传播。在疾病传播或信息流动的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。如H1H1流行病预测等数学模型，可以基于人类流动网络，传染性，或人与人之间的社会互动，让我们预测疾病的传播。在消灭疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的链接。在枢纽被感染后，它将将疾病传播到它所链接的节点。因此，选择性免疫那些枢纽可能是消灭传播性疾病的成本效率最高的策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17789</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17789"/>
		<updated>2020-11-03T07:20:47Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Emergence 涌现 */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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枢纽的涌现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
图4：基于Barabasi-Albert模型的网络增长（&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;）]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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网络起始于由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点组成的初始联通网络。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被链接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;个现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与现有节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;相连的概率&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;为&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;：&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度，求和则是针对所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;进行的。（分母的数值是网络边数的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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网络中枢纽的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，涌现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大互联网枢纽的8年后，Facebook出现了，并于2011年成为了全球最大的互联网枢纽。因此，在实际网络中，枢纽的增长和规模也取决于各种各样的其他属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽有诸多属性：&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络路径长度===&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽越多，节点之间的距离就越短。在无标度网络中，枢纽是连接小度节点的桥梁。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt;由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径长度的差异可能并不明显，但是在大型随机网络和无标度网络中，路径长度的差异是显著的。&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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无标度网络中的平均路径长度:&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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===Aging of hubs (nodes) 枢纽（节点）的老化===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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当旧的枢纽被隐藏在网络中时，这种现象便在真实网络中出现。这种现象导致了网络演化和拓扑结构的变化。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; 老化现象的例子可参照 Facebook 超越了网络中最大的枢纽 Google (自2000年以来最大的节点)。&lt;br /&gt;
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===Robustness and Attack Tolerance 鲁棒性和抗毁性===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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当节点发生随机故障或特定攻击时，枢纽是网络的重要构件。当网络中的节点发生随机故障时，枢纽影响网络的鲁棒性。&lt;br /&gt;
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The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除枢纽的几率很小。而去除小度节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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在对枢纽进行特定的攻击时，网络的完整性会相对较快地被破坏。由于小度节点大量的链接到枢纽，因此对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时头号玩家（枢纽）的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽可能会产生积极的影响，特定节点的消失可能会摧毁整个恐怖组织。网络的抗毁性可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种链接决定了网络的拓扑结构，从而影响了上文所讨论的网络鲁棒性。如果枢纽之间的链接数量与随机模式下的期望值相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽倾向于相互连接，同时避免链接到小度节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;同配网络 Assortative Network&amp;lt;/font&amp;gt;'''。这种网络的抗毁性相对较强，因为枢纽形成了一个核心团体，这对枢纽的移除来说是更加冗余的。如果枢纽避免相互链接，同时链接到小度节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;异配网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这种网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽，可能会破坏或摧毁整个网络。&lt;br /&gt;
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===Spreading phenomenon 传播现象===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
枢纽还负责要素在网络上的有效传播。在疾病传播或信息流动的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。如H1H1流行病预测等数学模型，可以基于人类流动网络，传染性，或人与人之间的社会互动，让我们预测疾病的传播。在消灭疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的链接。在枢纽被感染后，它将将疾病传播到它所链接的节点。因此，选择性免疫那些枢纽可能是消灭传播性疾病的成本效率最高的策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17788</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17788"/>
		<updated>2020-11-03T07:18:47Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Emergence 涌现 */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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枢纽的涌现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
&lt;br /&gt;
* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
&lt;br /&gt;
The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
图4：基于Barabasi-Albert模型的网络增长（&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;）]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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网络起始于由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点组成的初始联通网络。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被链接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;个现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与现有节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率为&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;：&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度，求和则是针对所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;进行的。（分母的数值是网络边数的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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网络中枢纽的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，涌现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大互联网枢纽的8年后，Facebook出现了，并于2011年成为了全球最大的互联网枢纽。因此，在实际网络中，枢纽的增长和规模也取决于各种各样的其他属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽有诸多属性：&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络路径长度===&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
&lt;br /&gt;
The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽越多，节点之间的距离就越短。在无标度网络中，枢纽是连接小度节点的桥梁。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt;由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径长度的差异可能并不明显，但是在大型随机网络和无标度网络中，路径长度的差异是显著的。&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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无标度网络中的平均路径长度:&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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===Aging of hubs (nodes) 枢纽（节点）的老化===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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当旧的枢纽被隐藏在网络中时，这种现象便在真实网络中出现。这种现象导致了网络演化和拓扑结构的变化。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; 老化现象的例子可参照 Facebook 超越了网络中最大的枢纽 Google (自2000年以来最大的节点)。&lt;br /&gt;
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===Robustness and Attack Tolerance 鲁棒性和抗毁性===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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当节点发生随机故障或特定攻击时，枢纽是网络的重要构件。当网络中的节点发生随机故障时，枢纽影响网络的鲁棒性。&lt;br /&gt;
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The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除枢纽的几率很小。而去除小度节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
在对枢纽进行特定的攻击时，网络的完整性会相对较快地被破坏。由于小度节点大量的链接到枢纽，因此对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时头号玩家（枢纽）的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽可能会产生积极的影响，特定节点的消失可能会摧毁整个恐怖组织。网络的抗毁性可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种链接决定了网络的拓扑结构，从而影响了上文所讨论的网络鲁棒性。如果枢纽之间的链接数量与随机模式下的期望值相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽倾向于相互连接，同时避免链接到小度节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;同配网络 Assortative Network&amp;lt;/font&amp;gt;'''。这种网络的抗毁性相对较强，因为枢纽形成了一个核心团体，这对枢纽的移除来说是更加冗余的。如果枢纽避免相互链接，同时链接到小度节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;异配网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这种网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽，可能会破坏或摧毁整个网络。&lt;br /&gt;
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===Spreading phenomenon 传播现象===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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枢纽还负责要素在网络上的有效传播。在疾病传播或信息流动的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。如H1H1流行病预测等数学模型，可以基于人类流动网络，传染性，或人与人之间的社会互动，让我们预测疾病的传播。在消灭疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的链接。在枢纽被感染后，它将将疾病传播到它所链接的节点。因此，选择性免疫那些枢纽可能是消灭传播性疾病的成本效率最高的策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17785</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17785"/>
		<updated>2020-11-03T06:36:21Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* 传播效应 Spreading phenomenon */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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枢纽的涌现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
&lt;br /&gt;
The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
&lt;br /&gt;
The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
&lt;br /&gt;
Barabási-Albert模型的数学解释:&lt;br /&gt;
&lt;br /&gt;
[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
图4：基于Barabasi-Albert模型的网络增长（&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;）]]&lt;br /&gt;
&lt;br /&gt;
The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
&lt;br /&gt;
The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
&lt;br /&gt;
网络起始于由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点组成的初始联通网络。&lt;br /&gt;
&lt;br /&gt;
New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
&lt;br /&gt;
每次向网络添加一个新节点。每个新的节点都被链接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;个现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与现有节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率为&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;：&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
&lt;br /&gt;
其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度，求和则是针对所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;进行的。（分母的数值是网络边数的两倍）。&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
&lt;br /&gt;
网络中枢纽的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，涌现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大互联网枢纽的8年后，Facebook出现了，并于2011年成为了全球最大的互联网枢纽。因此，在实际网络中，枢纽的增长和规模也取决于各种各样的其他属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
&lt;br /&gt;
== Attributes 属性==&lt;br /&gt;
&lt;br /&gt;
There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
&lt;br /&gt;
There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
&lt;br /&gt;
无标度网络中的枢纽有诸多属性：&lt;br /&gt;
&lt;br /&gt;
=== Shortening the path lengths in a network 缩短网络路径长度===&lt;br /&gt;
&lt;br /&gt;
The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
&lt;br /&gt;
The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
&lt;br /&gt;
网络中可观察到的枢纽越多，节点之间的距离就越短。在无标度网络中，枢纽是连接小度节点的桥梁。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt;由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径长度的差异可能并不明显，但是在大型随机网络和无标度网络中，路径长度的差异是显著的。&lt;br /&gt;
&lt;br /&gt;
Average path length in scale-free networks:&lt;br /&gt;
&lt;br /&gt;
Average path length in scale-free networks:&lt;br /&gt;
&lt;br /&gt;
无标度网络中的平均路径长度:&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Aging of hubs (nodes) 枢纽（节点）的老化===&lt;br /&gt;
&lt;br /&gt;
The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
&lt;br /&gt;
The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
&lt;br /&gt;
当旧的枢纽被隐藏在网络中时，这种现象便在真实网络中出现。这种现象导致了网络演化和拓扑结构的变化。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; 老化现象的例子可参照 Facebook 超越了网络中最大的枢纽 Google (自2000年以来最大的节点)。&lt;br /&gt;
&lt;br /&gt;
===Robustness and Attack Tolerance 鲁棒性和抗毁性===&lt;br /&gt;
&lt;br /&gt;
During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
&lt;br /&gt;
During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
&lt;br /&gt;
当节点发生随机故障或特定攻击时，枢纽是网络的重要构件。当网络中的节点发生随机故障时，枢纽影响网络的鲁棒性。&lt;br /&gt;
&lt;br /&gt;
The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
&lt;br /&gt;
The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
&lt;br /&gt;
由于枢纽与大量小度节点共存，随机故障删除枢纽的几率很小。而去除小度节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
在对枢纽进行特定的攻击时，网络的完整性会相对较快地被破坏。由于小度节点大量的链接到枢纽，因此对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时头号玩家（枢纽）的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽可能会产生积极的影响，特定节点的消失可能会摧毁整个恐怖组织。网络的抗毁性可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
&lt;br /&gt;
=== Degree correlation 度相关===&lt;br /&gt;
&lt;br /&gt;
The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
&lt;br /&gt;
The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种链接决定了网络的拓扑结构，从而影响了上文所讨论的网络鲁棒性。如果枢纽之间的链接数量与随机模式下的期望值相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽倾向于相互连接，同时避免链接到小度节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;同配网络 Assortative Network&amp;lt;/font&amp;gt;'''。这种网络的抗毁性相对较强，因为枢纽形成了一个核心团体，这对枢纽的移除来说是更加冗余的。如果枢纽避免相互链接，同时链接到小度节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;异配网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这种网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽，可能会破坏或摧毁整个网络。&lt;br /&gt;
&lt;br /&gt;
===Spreading phenomenon 传播现象===&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
枢纽还负责要素在网络上的有效传播。在疾病传播或信息流动的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。如H1H1流行病预测等数学模型，可以基于人类流动网络，传染性，或人与人之间的社会互动，让我们预测疾病的传播。在消灭疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的链接。在枢纽被感染后，它将将疾病传播到它所链接的节点。因此，选择性免疫那些枢纽可能是消灭传播性疾病的成本效率最高的策略。&lt;br /&gt;
&lt;br /&gt;
== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17783</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17783"/>
		<updated>2020-11-03T06:20:21Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Degree correlation 度相关 */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
&lt;br /&gt;
在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
&lt;br /&gt;
A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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枢纽的涌现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
&lt;br /&gt;
* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
&lt;br /&gt;
The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
图4：基于Barabasi-Albert模型的网络增长（&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;）]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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网络起始于由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点组成的初始联通网络。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被链接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;个现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与现有节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率为&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;：&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度，求和则是针对所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;进行的。（分母的数值是网络边数的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
&lt;br /&gt;
网络中枢纽的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，涌现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大互联网枢纽的8年后，Facebook出现了，并于2011年成为了全球最大的互联网枢纽。因此，在实际网络中，枢纽的增长和规模也取决于各种各样的其他属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽有诸多属性：&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络路径长度===&lt;br /&gt;
&lt;br /&gt;
The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
&lt;br /&gt;
The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽越多，节点之间的距离就越短。在无标度网络中，枢纽是连接小度节点的桥梁。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt;由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径长度的差异可能并不明显，但是在大型随机网络和无标度网络中，路径长度的差异是显著的。&lt;br /&gt;
&lt;br /&gt;
Average path length in scale-free networks:&lt;br /&gt;
&lt;br /&gt;
Average path length in scale-free networks:&lt;br /&gt;
&lt;br /&gt;
无标度网络中的平均路径长度:&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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===Aging of hubs (nodes) 枢纽（节点）的老化===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
&lt;br /&gt;
The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
&lt;br /&gt;
当旧的枢纽被隐藏在网络中时，这种现象便在真实网络中出现。这种现象导致了网络演化和拓扑结构的变化。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; 老化现象的例子可参照 Facebook 超越了网络中最大的枢纽 Google (自2000年以来最大的节点)。&lt;br /&gt;
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===Robustness and Attack Tolerance 鲁棒性和抗毁性===&lt;br /&gt;
&lt;br /&gt;
During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
&lt;br /&gt;
During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
&lt;br /&gt;
当节点发生随机故障或特定攻击时，枢纽是网络的重要构件。当网络中的节点发生随机故障时，枢纽影响网络的鲁棒性。&lt;br /&gt;
&lt;br /&gt;
The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
&lt;br /&gt;
The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除枢纽的几率很小。而去除小度节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
在对枢纽进行特定的攻击时，网络的完整性会相对较快地被破坏。由于小度节点大量的链接到枢纽，因此对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时头号玩家（枢纽）的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽可能会产生积极的影响，特定节点的消失可能会摧毁整个恐怖组织。网络的抗毁性可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种链接决定了网络的拓扑结构，从而影响了上文所讨论的网络鲁棒性。如果枢纽之间的链接数量与随机模式下的期望值相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽倾向于相互连接，同时避免链接到小度节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;同配网络 Assortative Network&amp;lt;/font&amp;gt;'''。这种网络的抗毁性相对较强，因为枢纽形成了一个核心团体，这对枢纽的移除来说是更加冗余的。如果枢纽避免相互链接，同时链接到小度节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;异配网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这种网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽，可能会破坏或摧毁整个网络。&lt;br /&gt;
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==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17770</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17770"/>
		<updated>2020-11-02T09:25:16Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Aging of hubs (nodes)枢纽（节点）的老化 */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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枢纽的涌现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
图4：基于Barabasi-Albert模型的网络增长（&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;）]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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网络起始于由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点组成的初始联通网络。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
&lt;br /&gt;
每次向网络添加一个新节点。每个新的节点都被链接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;个现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与现有节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率为&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;：&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
&lt;br /&gt;
其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度，求和则是针对所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;进行的。（分母的数值是网络边数的两倍）。&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
&lt;br /&gt;
网络中枢纽的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，涌现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大互联网枢纽的8年后，Facebook出现了，并于2011年成为了全球最大的互联网枢纽。因此，在实际网络中，枢纽的增长和规模也取决于各种各样的其他属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
&lt;br /&gt;
== Attributes 属性==&lt;br /&gt;
&lt;br /&gt;
There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
&lt;br /&gt;
There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
&lt;br /&gt;
无标度网络中的枢纽有诸多属性：&lt;br /&gt;
&lt;br /&gt;
=== Shortening the path lengths in a network 缩短网络路径长度===&lt;br /&gt;
&lt;br /&gt;
The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
&lt;br /&gt;
The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
&lt;br /&gt;
网络中可观察到的枢纽越多，节点之间的距离就越短。在无标度网络中，枢纽是连接小度节点的桥梁。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt;由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径长度的差异可能并不明显，但是在大型随机网络和无标度网络中，路径长度的差异是显著的。&lt;br /&gt;
&lt;br /&gt;
Average path length in scale-free networks:&lt;br /&gt;
&lt;br /&gt;
Average path length in scale-free networks:&lt;br /&gt;
&lt;br /&gt;
无标度网络中的平均路径长度:&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Aging of hubs (nodes) 枢纽（节点）的老化===&lt;br /&gt;
&lt;br /&gt;
The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
&lt;br /&gt;
The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
&lt;br /&gt;
当旧的枢纽被隐藏在网络中时，这种现象便在真实网络中出现。这种现象导致了网络演化和拓扑结构的变化。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; 老化现象的例子可参照 Facebook 超越了网络中最大的枢纽 Google (自2000年以来最大的节点)。&lt;br /&gt;
&lt;br /&gt;
===Robustness and Attack Tolerance 鲁棒性和抗毁性===&lt;br /&gt;
&lt;br /&gt;
During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
&lt;br /&gt;
During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
&lt;br /&gt;
当节点发生随机故障或特定攻击时，枢纽是网络的重要构件。当网络中的节点发生随机故障时，枢纽影响网络的鲁棒性。&lt;br /&gt;
&lt;br /&gt;
The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
&lt;br /&gt;
The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
&lt;br /&gt;
由于枢纽与大量小度节点共存，随机故障删除枢纽的几率很小。而去除小度节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
在对枢纽进行特定的攻击时，网络的完整性会相对较快地被破坏。由于小度节点大量的链接到枢纽，因此对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时头号玩家（枢纽）的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽可能会产生积极的影响，特定节点的消失可能会摧毁整个恐怖组织。网络的抗毁性可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
&lt;br /&gt;
=== Degree correlation 度相关===&lt;br /&gt;
&lt;br /&gt;
The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
&lt;br /&gt;
The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
&lt;br /&gt;
== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17769</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17769"/>
		<updated>2020-11-02T09:24:41Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* 鲁棒性和攻击容忍度 Robustness and Attack Tolerance */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
&lt;br /&gt;
In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
&lt;br /&gt;
In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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枢纽的涌现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
图4：基于Barabasi-Albert模型的网络增长（&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;）]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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网络起始于由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点组成的初始联通网络。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被链接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;个现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与现有节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率为&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;：&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度，求和则是针对所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;进行的。（分母的数值是网络边数的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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网络中枢纽的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，涌现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大互联网枢纽的8年后，Facebook出现了，并于2011年成为了全球最大的互联网枢纽。因此，在实际网络中，枢纽的增长和规模也取决于各种各样的其他属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽有诸多属性：&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络路径长度===&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽越多，节点之间的距离就越短。在无标度网络中，枢纽是连接小度节点的桥梁。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt;由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径长度的差异可能并不明显，但是在大型随机网络和无标度网络中，路径长度的差异是显著的。&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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无标度网络中的平均路径长度:&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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===Aging of hubs (nodes)枢纽（节点）的老化===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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当旧的枢纽被隐藏在网络中时，这种现象便在真实网络中出现。这种现象导致了网络演化和拓扑结构的变化。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; 老化现象的例子可参照 Facebook 超越了网络中最大的枢纽 Google (自2000年以来最大的节点)。&lt;br /&gt;
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===Robustness and Attack Tolerance 鲁棒性和抗毁性===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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当节点发生随机故障或特定攻击时，枢纽是网络的重要构件。当网络中的节点发生随机故障时，枢纽影响网络的鲁棒性。&lt;br /&gt;
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The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除枢纽的几率很小。而去除小度节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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在对枢纽进行特定的攻击时，网络的完整性会相对较快地被破坏。由于小度节点大量的链接到枢纽，因此对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时头号玩家（枢纽）的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽可能会产生积极的影响，特定节点的消失可能会摧毁整个恐怖组织。网络的抗毁性可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
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==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17768</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17768"/>
		<updated>2020-11-02T09:13:24Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Aging of hubs (nodes)枢纽（节点）的老化 */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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枢纽的涌现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
图4：基于Barabasi-Albert模型的网络增长（&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;）]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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网络起始于由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点组成的初始联通网络。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被链接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;个现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与现有节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率为&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;：&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
&lt;br /&gt;
其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度，求和则是针对所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;进行的。（分母的数值是网络边数的两倍）。&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
&lt;br /&gt;
网络中枢纽的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，涌现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大互联网枢纽的8年后，Facebook出现了，并于2011年成为了全球最大的互联网枢纽。因此，在实际网络中，枢纽的增长和规模也取决于各种各样的其他属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
&lt;br /&gt;
== Attributes 属性==&lt;br /&gt;
&lt;br /&gt;
There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
&lt;br /&gt;
There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
&lt;br /&gt;
无标度网络中的枢纽有诸多属性：&lt;br /&gt;
&lt;br /&gt;
=== Shortening the path lengths in a network 缩短网络路径长度===&lt;br /&gt;
&lt;br /&gt;
The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
&lt;br /&gt;
The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
&lt;br /&gt;
网络中可观察到的枢纽越多，节点之间的距离就越短。在无标度网络中，枢纽是连接小度节点的桥梁。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt;由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径长度的差异可能并不明显，但是在大型随机网络和无标度网络中，路径长度的差异是显著的。&lt;br /&gt;
&lt;br /&gt;
Average path length in scale-free networks:&lt;br /&gt;
&lt;br /&gt;
Average path length in scale-free networks:&lt;br /&gt;
&lt;br /&gt;
无标度网络中的平均路径长度:&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Aging of hubs (nodes)枢纽（节点）的老化===&lt;br /&gt;
&lt;br /&gt;
The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
&lt;br /&gt;
The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
&lt;br /&gt;
当旧的枢纽被隐藏在网络中时，这种现象便在真实网络中出现。这种现象导致了网络演化和拓扑结构的变化。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; 老化现象的例子可参照 Facebook 超越了网络中最大的枢纽 Google (自2000年以来最大的节点)。&lt;br /&gt;
&lt;br /&gt;
=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;鲁棒性和攻击容忍度 Robustness and Attack Tolerance&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
&lt;br /&gt;
During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
&lt;br /&gt;
During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
&lt;br /&gt;
随机故障的节点或定向攻击网络关键组成部分的枢纽。在网络枢纽节点的随机失效过程中，网络的鲁棒性是由节点的随机失效决定的。&amp;lt; ref &amp;gt; { cite journal | title = Resilience of the Internet to Random breaks | &lt;br /&gt;
&lt;br /&gt;
journal=Phys. Rev. Lett.|&lt;br /&gt;
&lt;br /&gt;
journal=Phys. Rev. Lett.|&lt;br /&gt;
&lt;br /&gt;
日记 = 体育。牧师。李特 | &lt;br /&gt;
&lt;br /&gt;
year=2000|&lt;br /&gt;
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year=2000|&lt;br /&gt;
&lt;br /&gt;
2000年&lt;br /&gt;
&lt;br /&gt;
first=Reoven|&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
&lt;br /&gt;
1 = Reoven | &lt;br /&gt;
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last=Cohen|&lt;br /&gt;
&lt;br /&gt;
last=Cohen|&lt;br /&gt;
&lt;br /&gt;
最后 = Cohen | &lt;br /&gt;
&lt;br /&gt;
first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
&lt;br /&gt;
first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
&lt;br /&gt;
首先2 = k。2 = Erez | first3 = d.3 = ben-Avraham | first4 = s | last4 = Havlin | authorlink4 = Shlomo Havlin | &lt;br /&gt;
&lt;br /&gt;
volume=85|&lt;br /&gt;
&lt;br /&gt;
volume=85|&lt;br /&gt;
&lt;br /&gt;
85 | &lt;br /&gt;
&lt;br /&gt;
pages=4626–8|&lt;br /&gt;
&lt;br /&gt;
pages=4626–8|&lt;br /&gt;
&lt;br /&gt;
页数 = 4626-8&lt;br /&gt;
&lt;br /&gt;
doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
&lt;br /&gt;
doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
&lt;br /&gt;
Doi = 10.1103/physrvlett. 85.4626 | &lt;br /&gt;
&lt;br /&gt;
url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
&lt;br /&gt;
url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
&lt;br /&gt;
Http://link.aps.org/doi/10.1103/physrevlett.85.4626&lt;br /&gt;
&lt;br /&gt;
|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
&lt;br /&gt;
|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
&lt;br /&gt;
| bibcode = 2000PhRvL. . 85.4626 c | arxiv = cond-mat/0007048 | pmid = 11082612}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
&lt;br /&gt;
&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
&lt;br /&gt;
由于枢纽与大量小度节点共存，随机故障删除它的几率很小。而去除小节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
在对枢纽进行有针对性的攻击时，网络的完整性会相对较快地崩溃。由于小节点主要连接到枢纽节点，对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时最大的参与者(枢纽)的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽节点可能会产生积极的影响，目标节点的消失可能会摧毁整个恐怖组织。网络的攻击容忍度可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=== Degree correlation 度相关===&lt;br /&gt;
&lt;br /&gt;
The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
&lt;br /&gt;
The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
&lt;br /&gt;
== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17767</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17767"/>
		<updated>2020-11-02T09:12:50Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* 枢纽节点的老化 Aging of hubs (nodes) */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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枢纽的涌现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
图4：基于Barabasi-Albert模型的网络增长（&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;）]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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网络起始于由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点组成的初始联通网络。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被链接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;个现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与现有节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率为&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;：&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度，求和则是针对所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;进行的。（分母的数值是网络边数的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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网络中枢纽的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，涌现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大互联网枢纽的8年后，Facebook出现了，并于2011年成为了全球最大的互联网枢纽。因此，在实际网络中，枢纽的增长和规模也取决于各种各样的其他属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽有诸多属性：&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络路径长度===&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽越多，节点之间的距离就越短。在无标度网络中，枢纽是连接小度节点的桥梁。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt;由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径长度的差异可能并不明显，但是在大型随机网络和无标度网络中，路径长度的差异是显著的。&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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无标度网络中的平均路径长度:&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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===Aging of hubs (nodes)枢纽（节点）的老化===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).{{Citation needed|date=May 2016}}&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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当旧的枢纽被隐藏在网络中时，这种现象便在真实网络中出现。这种现象导致了网络演化和拓扑结构的变化。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; 老化现象的例子可参照 Facebook 超越了网络中最大的枢纽 Google (自2000年以来最大的节点)。{{Citation needed|date=May 2016}}&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;鲁棒性和攻击容忍度 Robustness and Attack Tolerance&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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随机故障的节点或定向攻击网络关键组成部分的枢纽。在网络枢纽节点的随机失效过程中，网络的鲁棒性是由节点的随机失效决定的。&amp;lt; ref &amp;gt; { cite journal | title = Resilience of the Internet to Random breaks | &lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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日记 = 体育。牧师。李特 | &lt;br /&gt;
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year=2000|&lt;br /&gt;
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year=2000|&lt;br /&gt;
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2000年&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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1 = Reoven | &lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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最后 = Cohen | &lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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首先2 = k。2 = Erez | first3 = d.3 = ben-Avraham | first4 = s | last4 = Havlin | authorlink4 = Shlomo Havlin | &lt;br /&gt;
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volume=85|&lt;br /&gt;
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volume=85|&lt;br /&gt;
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85 | &lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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页数 = 4626-8&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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Doi = 10.1103/physrvlett. 85.4626 | &lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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Http://link.aps.org/doi/10.1103/physrevlett.85.4626&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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| bibcode = 2000PhRvL. . 85.4626 c | arxiv = cond-mat/0007048 | pmid = 11082612}&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除它的几率很小。而去除小节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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在对枢纽进行有针对性的攻击时，网络的完整性会相对较快地崩溃。由于小节点主要连接到枢纽节点，对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时最大的参与者(枢纽)的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽节点可能会产生积极的影响，目标节点的消失可能会摧毁整个恐怖组织。网络的攻击容忍度可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
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==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17766</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17766"/>
		<updated>2020-11-02T09:09:53Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Shortening the path lengths in a network 缩短网络路径长度 */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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枢纽的涌现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
图4：基于Barabasi-Albert模型的网络增长（&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;）]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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网络起始于由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点组成的初始联通网络。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被链接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;个现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与现有节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率为&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;：&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度，求和则是针对所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;进行的。（分母的数值是网络边数的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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网络中枢纽的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，涌现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大互联网枢纽的8年后，Facebook出现了，并于2011年成为了全球最大的互联网枢纽。因此，在实际网络中，枢纽的增长和规模也取决于各种各样的其他属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽有诸多属性：&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络路径长度===&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽越多，节点之间的距离就越短。在无标度网络中，枢纽是连接小度节点的桥梁。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt;由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径长度的差异可能并不明显，但是在大型随机网络和无标度网络中，路径长度的差异是显著的。&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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无标度网络中的平均路径长度:&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽节点的老化 Aging of hubs (nodes)&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).{{Citation needed|date=May 2016}}&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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这种现象在真实网络中有所出现，当旧的枢纽被隐藏在网络中时。这种现象导致了网络演化和拓扑结构的变化。老化现象的例子可参照 Facebook 超越了网络中最大的中心 Google (自2000年以来最大的节点)。&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;鲁棒性和攻击容忍度 Robustness and Attack Tolerance&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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随机故障的节点或定向攻击网络关键组成部分的枢纽。在网络枢纽节点的随机失效过程中，网络的鲁棒性是由节点的随机失效决定的。&amp;lt; ref &amp;gt; { cite journal | title = Resilience of the Internet to Random breaks | &lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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日记 = 体育。牧师。李特 | &lt;br /&gt;
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year=2000|&lt;br /&gt;
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year=2000|&lt;br /&gt;
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2000年&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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1 = Reoven | &lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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最后 = Cohen | &lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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首先2 = k。2 = Erez | first3 = d.3 = ben-Avraham | first4 = s | last4 = Havlin | authorlink4 = Shlomo Havlin | &lt;br /&gt;
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volume=85|&lt;br /&gt;
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volume=85|&lt;br /&gt;
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85 | &lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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页数 = 4626-8&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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Doi = 10.1103/physrvlett. 85.4626 | &lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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Http://link.aps.org/doi/10.1103/physrevlett.85.4626&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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| bibcode = 2000PhRvL. . 85.4626 c | arxiv = cond-mat/0007048 | pmid = 11082612}&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除它的几率很小。而去除小节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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在对枢纽进行有针对性的攻击时，网络的完整性会相对较快地崩溃。由于小节点主要连接到枢纽节点，对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时最大的参与者(枢纽)的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽节点可能会产生积极的影响，目标节点的消失可能会摧毁整个恐怖组织。网络的攻击容忍度可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
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==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17758</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17758"/>
		<updated>2020-11-02T08:14:40Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Attributes 属性 */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
&lt;br /&gt;
In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
&lt;br /&gt;
In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
&lt;br /&gt;
在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
&lt;br /&gt;
[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
&lt;br /&gt;
[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
&lt;br /&gt;
A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
&lt;br /&gt;
A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
&lt;br /&gt;
[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
&lt;br /&gt;
枢纽的涌现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
&lt;br /&gt;
* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
&lt;br /&gt;
*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
&lt;br /&gt;
* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
&lt;br /&gt;
*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
&lt;br /&gt;
The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
&lt;br /&gt;
The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
&lt;br /&gt;
Barabási-Albert模型的数学解释:&lt;br /&gt;
&lt;br /&gt;
[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
图4：基于Barabasi-Albert模型的网络增长（&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;）]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
&lt;br /&gt;
The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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网络起始于由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点组成的初始联通网络。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
&lt;br /&gt;
每次向网络添加一个新节点。每个新的节点都被链接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;个现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与现有节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率为&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;：&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度，求和则是针对所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;进行的。（分母的数值是网络边数的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
&lt;br /&gt;
网络中枢纽的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，涌现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大互联网枢纽的8年后，Facebook出现了，并于2011年成为了全球最大的互联网枢纽。因此，在实际网络中，枢纽的增长和规模也取决于各种各样的其他属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
&lt;br /&gt;
There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽有诸多属性：&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络路径长度===&lt;br /&gt;
&lt;br /&gt;
The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
&lt;br /&gt;
The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
&lt;br /&gt;
网络中可观察到的枢纽越多，节点之间的距离就越短。在无标度网络中，枢纽是连接度小的节点的桥梁。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt;由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径距离的差异可能并不明显，但是在大型随机网络和无标度网络中，路径距离的差异是显著的。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Average path length in scale-free networks:&lt;br /&gt;
&lt;br /&gt;
Average path length in scale-free networks:&lt;br /&gt;
&lt;br /&gt;
无标度网络中的平均路径长度:&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽节点的老化 Aging of hubs (nodes)&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
&lt;br /&gt;
The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).{{Citation needed|date=May 2016}}&lt;br /&gt;
&lt;br /&gt;
The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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这种现象在真实网络中有所出现，当旧的枢纽被隐藏在网络中时。这种现象导致了网络演化和拓扑结构的变化。老化现象的例子可参照 Facebook 超越了网络中最大的中心 Google (自2000年以来最大的节点)。&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;鲁棒性和攻击容忍度 Robustness and Attack Tolerance&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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随机故障的节点或定向攻击网络关键组成部分的枢纽。在网络枢纽节点的随机失效过程中，网络的鲁棒性是由节点的随机失效决定的。&amp;lt; ref &amp;gt; { cite journal | title = Resilience of the Internet to Random breaks | &lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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日记 = 体育。牧师。李特 | &lt;br /&gt;
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year=2000|&lt;br /&gt;
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year=2000|&lt;br /&gt;
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2000年&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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1 = Reoven | &lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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最后 = Cohen | &lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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首先2 = k。2 = Erez | first3 = d.3 = ben-Avraham | first4 = s | last4 = Havlin | authorlink4 = Shlomo Havlin | &lt;br /&gt;
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volume=85|&lt;br /&gt;
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volume=85|&lt;br /&gt;
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85 | &lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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页数 = 4626-8&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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Doi = 10.1103/physrvlett. 85.4626 | &lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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Http://link.aps.org/doi/10.1103/physrevlett.85.4626&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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| bibcode = 2000PhRvL. . 85.4626 c | arxiv = cond-mat/0007048 | pmid = 11082612}&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除它的几率很小。而去除小节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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在对枢纽进行有针对性的攻击时，网络的完整性会相对较快地崩溃。由于小节点主要连接到枢纽节点，对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时最大的参与者(枢纽)的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽节点可能会产生积极的影响，目标节点的消失可能会摧毁整个恐怖组织。网络的攻击容忍度可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
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==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17757</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17757"/>
		<updated>2020-11-02T07:04:48Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Emergence 涌现 */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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枢纽的涌现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
图4：基于Barabasi-Albert模型的网络增长（&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;）]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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网络起始于由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点组成的初始联通网络。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被链接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;个现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与现有节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率为&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;：&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度，求和则是针对所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;进行的。（分母的数值是网络边数的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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网络中枢纽的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，涌现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大互联网枢纽的8年后，Facebook出现了，并于2011年成为了全球最大的互联网枢纽。因此，在实际网络中，枢纽的增长和规模也取决于各种各样的其他属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽节点有几个属性&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络中的路径距离===&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽节点越多，节点之间的距离就越小。在无标度网络中，枢纽是连接度小的节点的桥梁。由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径距离的差异可能并不明显，但是在大型随机网络和无标度网络中，路径距离的差异是显著的。&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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无标度网络中的平均路径长度:&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽节点的老化 Aging of hubs (nodes)&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).{{Citation needed|date=May 2016}}&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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这种现象在真实网络中有所出现，当旧的枢纽被隐藏在网络中时。这种现象导致了网络演化和拓扑结构的变化。老化现象的例子可参照 Facebook 超越了网络中最大的中心 Google (自2000年以来最大的节点)。&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;鲁棒性和攻击容忍度 Robustness and Attack Tolerance&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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随机故障的节点或定向攻击网络关键组成部分的枢纽。在网络枢纽节点的随机失效过程中，网络的鲁棒性是由节点的随机失效决定的。&amp;lt; ref &amp;gt; { cite journal | title = Resilience of the Internet to Random breaks | &lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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日记 = 体育。牧师。李特 | &lt;br /&gt;
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year=2000|&lt;br /&gt;
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year=2000|&lt;br /&gt;
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2000年&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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1 = Reoven | &lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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最后 = Cohen | &lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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首先2 = k。2 = Erez | first3 = d.3 = ben-Avraham | first4 = s | last4 = Havlin | authorlink4 = Shlomo Havlin | &lt;br /&gt;
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volume=85|&lt;br /&gt;
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volume=85|&lt;br /&gt;
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85 | &lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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页数 = 4626-8&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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Doi = 10.1103/physrvlett. 85.4626 | &lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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Http://link.aps.org/doi/10.1103/physrevlett.85.4626&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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| bibcode = 2000PhRvL. . 85.4626 c | arxiv = cond-mat/0007048 | pmid = 11082612}&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除它的几率很小。而去除小节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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在对枢纽进行有针对性的攻击时，网络的完整性会相对较快地崩溃。由于小节点主要连接到枢纽节点，对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时最大的参与者(枢纽)的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽节点可能会产生积极的影响，目标节点的消失可能会摧毁整个恐怖组织。网络的攻击容忍度可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
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==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17756</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17756"/>
		<updated>2020-11-02T07:03:43Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Emergence 涌现 */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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枢纽的涌现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
图4：基于Barabasi-Albert模型的网络增长（&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;）]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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网络起始于由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点组成的初始联通网络。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被链接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;个现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与现有节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率为&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;：&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度，求和则是针对所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;进行的。（分母的数值是网络边数的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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网络中枢纽的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，涌现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大互联网枢纽的8年后，Facebook出现了，并于2011年成为了全球最大的互联网枢纽。因此，在实际网络中，枢纽的增长和规模也取决于各种各样的其他特性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽节点有几个属性&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络中的路径距离===&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽节点越多，节点之间的距离就越小。在无标度网络中，枢纽是连接度小的节点的桥梁。由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径距离的差异可能并不明显，但是在大型随机网络和无标度网络中，路径距离的差异是显著的。&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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无标度网络中的平均路径长度:&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽节点的老化 Aging of hubs (nodes)&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).{{Citation needed|date=May 2016}}&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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这种现象在真实网络中有所出现，当旧的枢纽被隐藏在网络中时。这种现象导致了网络演化和拓扑结构的变化。老化现象的例子可参照 Facebook 超越了网络中最大的中心 Google (自2000年以来最大的节点)。&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;鲁棒性和攻击容忍度 Robustness and Attack Tolerance&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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随机故障的节点或定向攻击网络关键组成部分的枢纽。在网络枢纽节点的随机失效过程中，网络的鲁棒性是由节点的随机失效决定的。&amp;lt; ref &amp;gt; { cite journal | title = Resilience of the Internet to Random breaks | &lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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日记 = 体育。牧师。李特 | &lt;br /&gt;
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year=2000|&lt;br /&gt;
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year=2000|&lt;br /&gt;
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2000年&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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1 = Reoven | &lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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最后 = Cohen | &lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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首先2 = k。2 = Erez | first3 = d.3 = ben-Avraham | first4 = s | last4 = Havlin | authorlink4 = Shlomo Havlin | &lt;br /&gt;
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volume=85|&lt;br /&gt;
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volume=85|&lt;br /&gt;
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85 | &lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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页数 = 4626-8&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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Doi = 10.1103/physrvlett. 85.4626 | &lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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Http://link.aps.org/doi/10.1103/physrevlett.85.4626&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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| bibcode = 2000PhRvL. . 85.4626 c | arxiv = cond-mat/0007048 | pmid = 11082612}&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除它的几率很小。而去除小节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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在对枢纽进行有针对性的攻击时，网络的完整性会相对较快地崩溃。由于小节点主要连接到枢纽节点，对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时最大的参与者(枢纽)的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽节点可能会产生积极的影响，目标节点的消失可能会摧毁整个恐怖组织。网络的攻击容忍度可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
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==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17755</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17755"/>
		<updated>2020-11-02T07:01:55Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Emergence 出现 */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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枢纽的涌现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
图4：基于Barabasi-Albert模型的网络增长（&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;）]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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网络起始于由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点组成的初始联通网络。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被链接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;个现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与现有节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率为&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度，求和则是针对所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;进行的。（分母的数值是网络边数的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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网络中枢纽的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，涌现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大互联网枢纽的8年后，Facebook出现了，并于2011年成为了全球最大的互联网枢纽。因此，在实际网络中，枢纽的增长和规模也取决于各种各样的其他特性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽节点有几个属性&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络中的路径距离===&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽节点越多，节点之间的距离就越小。在无标度网络中，枢纽是连接度小的节点的桥梁。由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径距离的差异可能并不明显，但是在大型随机网络和无标度网络中，路径距离的差异是显著的。&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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无标度网络中的平均路径长度:&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽节点的老化 Aging of hubs (nodes)&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).{{Citation needed|date=May 2016}}&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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这种现象在真实网络中有所出现，当旧的枢纽被隐藏在网络中时。这种现象导致了网络演化和拓扑结构的变化。老化现象的例子可参照 Facebook 超越了网络中最大的中心 Google (自2000年以来最大的节点)。&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;鲁棒性和攻击容忍度 Robustness and Attack Tolerance&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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随机故障的节点或定向攻击网络关键组成部分的枢纽。在网络枢纽节点的随机失效过程中，网络的鲁棒性是由节点的随机失效决定的。&amp;lt; ref &amp;gt; { cite journal | title = Resilience of the Internet to Random breaks | &lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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日记 = 体育。牧师。李特 | &lt;br /&gt;
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year=2000|&lt;br /&gt;
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year=2000|&lt;br /&gt;
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2000年&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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1 = Reoven | &lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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最后 = Cohen | &lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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首先2 = k。2 = Erez | first3 = d.3 = ben-Avraham | first4 = s | last4 = Havlin | authorlink4 = Shlomo Havlin | &lt;br /&gt;
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volume=85|&lt;br /&gt;
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volume=85|&lt;br /&gt;
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85 | &lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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页数 = 4626-8&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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Doi = 10.1103/physrvlett. 85.4626 | &lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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Http://link.aps.org/doi/10.1103/physrevlett.85.4626&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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| bibcode = 2000PhRvL. . 85.4626 c | arxiv = cond-mat/0007048 | pmid = 11082612}&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除它的几率很小。而去除小节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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在对枢纽进行有针对性的攻击时，网络的完整性会相对较快地崩溃。由于小节点主要连接到枢纽节点，对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时最大的参与者(枢纽)的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽节点可能会产生积极的影响，目标节点的消失可能会摧毁整个恐怖组织。网络的攻击容忍度可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
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==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17578</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17578"/>
		<updated>2020-10-31T11:14:21Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Emergence 出现 */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 出现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&lt;br /&gt;
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枢纽的成因可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
图4：基于Barabasi-Albert模型的网络增长（&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;）]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
&lt;br /&gt;
网络起始于由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点组成的初始联通网络。&lt;br /&gt;
&lt;br /&gt;
New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
&lt;br /&gt;
每次向网络添加一个新节点。每个新的节点都被连接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率是&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
&lt;br /&gt;
其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度数，这个和取自所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;。（分母的结果是当前网络中边的两倍）。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
&lt;br /&gt;
网络中枢纽节点的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，出现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大的互联网中心8年后，Facebook 出现了，然而在2011年，Facebook 成为了全球最大的互联网中心。因此，在实际网络中，枢纽的增长和规模也取决于各种属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
&lt;br /&gt;
== Attributes 属性==&lt;br /&gt;
&lt;br /&gt;
There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
&lt;br /&gt;
There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
&lt;br /&gt;
无标度网络中的枢纽节点有几个属性&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=== Shortening the path lengths in a network 缩短网络中的路径距离===&lt;br /&gt;
&lt;br /&gt;
The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
&lt;br /&gt;
The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
&lt;br /&gt;
网络中可观察到的枢纽节点越多，节点之间的距离就越小。在无标度网络中，枢纽是连接度小的节点的桥梁。由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径距离的差异可能并不明显，但是在大型随机网络和无标度网络中，路径距离的差异是显著的。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Average path length in scale-free networks:&lt;br /&gt;
&lt;br /&gt;
Average path length in scale-free networks:&lt;br /&gt;
&lt;br /&gt;
无标度网络中的平均路径长度:&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽节点的老化 Aging of hubs (nodes)&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
&lt;br /&gt;
The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).{{Citation needed|date=May 2016}}&lt;br /&gt;
&lt;br /&gt;
The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
&lt;br /&gt;
这种现象在真实网络中有所出现，当旧的枢纽被隐藏在网络中时。这种现象导致了网络演化和拓扑结构的变化。老化现象的例子可参照 Facebook 超越了网络中最大的中心 Google (自2000年以来最大的节点)。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;鲁棒性和攻击容忍度 Robustness and Attack Tolerance&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
&lt;br /&gt;
During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
&lt;br /&gt;
During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
&lt;br /&gt;
随机故障的节点或定向攻击网络关键组成部分的枢纽。在网络枢纽节点的随机失效过程中，网络的鲁棒性是由节点的随机失效决定的。&amp;lt; ref &amp;gt; { cite journal | title = Resilience of the Internet to Random breaks | &lt;br /&gt;
&lt;br /&gt;
journal=Phys. Rev. Lett.|&lt;br /&gt;
&lt;br /&gt;
journal=Phys. Rev. Lett.|&lt;br /&gt;
&lt;br /&gt;
日记 = 体育。牧师。李特 | &lt;br /&gt;
&lt;br /&gt;
year=2000|&lt;br /&gt;
&lt;br /&gt;
year=2000|&lt;br /&gt;
&lt;br /&gt;
2000年&lt;br /&gt;
&lt;br /&gt;
first=Reoven|&lt;br /&gt;
&lt;br /&gt;
first=Reoven|&lt;br /&gt;
&lt;br /&gt;
1 = Reoven | &lt;br /&gt;
&lt;br /&gt;
last=Cohen|&lt;br /&gt;
&lt;br /&gt;
last=Cohen|&lt;br /&gt;
&lt;br /&gt;
最后 = Cohen | &lt;br /&gt;
&lt;br /&gt;
first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
&lt;br /&gt;
first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
&lt;br /&gt;
首先2 = k。2 = Erez | first3 = d.3 = ben-Avraham | first4 = s | last4 = Havlin | authorlink4 = Shlomo Havlin | &lt;br /&gt;
&lt;br /&gt;
volume=85|&lt;br /&gt;
&lt;br /&gt;
volume=85|&lt;br /&gt;
&lt;br /&gt;
85 | &lt;br /&gt;
&lt;br /&gt;
pages=4626–8|&lt;br /&gt;
&lt;br /&gt;
pages=4626–8|&lt;br /&gt;
&lt;br /&gt;
页数 = 4626-8&lt;br /&gt;
&lt;br /&gt;
doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
&lt;br /&gt;
doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
&lt;br /&gt;
Doi = 10.1103/physrvlett. 85.4626 | &lt;br /&gt;
&lt;br /&gt;
url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
&lt;br /&gt;
url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
&lt;br /&gt;
Http://link.aps.org/doi/10.1103/physrevlett.85.4626&lt;br /&gt;
&lt;br /&gt;
|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
&lt;br /&gt;
|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
&lt;br /&gt;
| bibcode = 2000PhRvL. . 85.4626 c | arxiv = cond-mat/0007048 | pmid = 11082612}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
&lt;br /&gt;
&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
&lt;br /&gt;
由于枢纽与大量小度节点共存，随机故障删除它的几率很小。而去除小节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
在对枢纽进行有针对性的攻击时，网络的完整性会相对较快地崩溃。由于小节点主要连接到枢纽节点，对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时最大的参与者(枢纽)的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽节点可能会产生积极的影响，目标节点的消失可能会摧毁整个恐怖组织。网络的攻击容忍度可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=== Degree correlation 度相关===&lt;br /&gt;
&lt;br /&gt;
The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
&lt;br /&gt;
The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17577</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17577"/>
		<updated>2020-10-31T11:10:21Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Emergence 出现 */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 出现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&amp;lt;ref name=RMP&amp;gt;{{Cite journal&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&amp;lt;ref name=RMP&amp;gt;{{Cite journal&lt;br /&gt;
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枢纽的成因可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
根据 Barabasi-Albert 模型 &amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt; 分析了网络生长的步骤]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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这个网络从一个初始的由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点构成的连接网络开始。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被连接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率是&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度数，这个和取自所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;。（分母的结果是当前网络中边的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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网络中枢纽节点的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，出现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大的互联网中心8年后，Facebook 出现了，然而在2011年，Facebook 成为了全球最大的互联网中心。因此，在实际网络中，枢纽的增长和规模也取决于各种属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽节点有几个属性&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络中的路径距离===&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽节点越多，节点之间的距离就越小。在无标度网络中，枢纽是连接度小的节点的桥梁。由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径距离的差异可能并不明显，但是在大型随机网络和无标度网络中，路径距离的差异是显著的。&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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无标度网络中的平均路径长度:&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽节点的老化 Aging of hubs (nodes)&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).{{Citation needed|date=May 2016}}&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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这种现象在真实网络中有所出现，当旧的枢纽被隐藏在网络中时。这种现象导致了网络演化和拓扑结构的变化。老化现象的例子可参照 Facebook 超越了网络中最大的中心 Google (自2000年以来最大的节点)。&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;鲁棒性和攻击容忍度 Robustness and Attack Tolerance&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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随机故障的节点或定向攻击网络关键组成部分的枢纽。在网络枢纽节点的随机失效过程中，网络的鲁棒性是由节点的随机失效决定的。&amp;lt; ref &amp;gt; { cite journal | title = Resilience of the Internet to Random breaks | &lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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日记 = 体育。牧师。李特 | &lt;br /&gt;
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year=2000|&lt;br /&gt;
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year=2000|&lt;br /&gt;
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2000年&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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1 = Reoven | &lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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最后 = Cohen | &lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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首先2 = k。2 = Erez | first3 = d.3 = ben-Avraham | first4 = s | last4 = Havlin | authorlink4 = Shlomo Havlin | &lt;br /&gt;
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volume=85|&lt;br /&gt;
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volume=85|&lt;br /&gt;
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85 | &lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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页数 = 4626-8&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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Doi = 10.1103/physrvlett. 85.4626 | &lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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Http://link.aps.org/doi/10.1103/physrevlett.85.4626&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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| bibcode = 2000PhRvL. . 85.4626 c | arxiv = cond-mat/0007048 | pmid = 11082612}&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除它的几率很小。而去除小节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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在对枢纽进行有针对性的攻击时，网络的完整性会相对较快地崩溃。由于小节点主要连接到枢纽节点，对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时最大的参与者(枢纽)的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽节点可能会产生积极的影响，目标节点的消失可能会摧毁整个恐怖组织。网络的攻击容忍度可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
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==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17576</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17576"/>
		<updated>2020-10-31T11:08:54Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Emergence 出现 */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 出现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&amp;lt;ref name=RMP&amp;gt;{{Cite journal&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&amp;lt;ref name=RMP&amp;gt;{{Cite journal&lt;br /&gt;
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枢纽的成因可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。{ Cite journal&lt;br /&gt;
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 | url = http://www.nd.edu/~networks/Publication%20Categories/03%20Journal%20Articles/Physics/StatisticalMechanics_Rev%20of%20Modern%20Physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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 | url = http://www.nd.edu/~networks/Publication%20Categories/03%20Journal%20Articles/Physics/StatisticalMechanics_Rev%20of%20Modern%20Physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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Http://www.nd.edu/~networks/publication%20categories/03%20journal%20articles/physics/statisticalmechanics_rev%20of%20modern%20physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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 | authorlink1 = Réka Albert | first1 = Réka | last1 = Albert&lt;br /&gt;
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 | authorlink1 = Réka Albert | first1 = Réka | last1 = Albert&lt;br /&gt;
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1 = r é ka Albert | first1 = r é ka | last1 = Albert&lt;br /&gt;
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 | authorlink2 = Albert-László Barabási | first2 = Albert-László | last2 = Barabási&lt;br /&gt;
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 | authorlink2 = Albert-László Barabási | first2 = Albert-László | last2 = Barabási&lt;br /&gt;
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2 = albert-lászló Barabási | first2 = albert-lászló | last2 = Barabási&lt;br /&gt;
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 | title = Statistical mechanics of complex networks&lt;br /&gt;
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 | title = Statistical mechanics of complex networks&lt;br /&gt;
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| title = 复杂网络的统计力学&lt;br /&gt;
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 | journal = [[Reviews of Modern Physics]]&lt;br /&gt;
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 | journal = Reviews of Modern Physics&lt;br /&gt;
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| 杂志 = 现代物理学评论&lt;br /&gt;
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 | volume = 74&lt;br /&gt;
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 | volume = 74&lt;br /&gt;
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74&lt;br /&gt;
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 | pages = 47–97&lt;br /&gt;
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 | pages = 47–97&lt;br /&gt;
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| 页数 = 47-97&lt;br /&gt;
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 | year = 2002&lt;br /&gt;
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 | year = 2002&lt;br /&gt;
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2002年&lt;br /&gt;
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 | doi = 10.1103/RevModPhys.74.47&lt;br /&gt;
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 | doi = 10.1103/RevModPhys.74.47&lt;br /&gt;
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10.1103/RevModPhys. 74.47&lt;br /&gt;
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 | bibcode=2002RvMP...74...47A&lt;br /&gt;
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 | bibcode=2002RvMP...74...47A&lt;br /&gt;
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2002RvMP... 74... 47A&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的上升。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
根据 Barabasi-Albert 模型 &amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt; 分析了网络生长的步骤]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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这个网络从一个初始的由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点构成的连接网络开始。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被连接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率是&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度数，这个和取自所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;。（分母的结果是当前网络中边的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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网络中枢纽节点的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，出现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大的互联网中心8年后，Facebook 出现了，然而在2011年，Facebook 成为了全球最大的互联网中心。因此，在实际网络中，枢纽的增长和规模也取决于各种属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽节点有几个属性&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络中的路径距离===&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽节点越多，节点之间的距离就越小。在无标度网络中，枢纽是连接度小的节点的桥梁。由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径距离的差异可能并不明显，但是在大型随机网络和无标度网络中，路径距离的差异是显著的。&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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无标度网络中的平均路径长度:&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽节点的老化 Aging of hubs (nodes)&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).{{Citation needed|date=May 2016}}&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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这种现象在真实网络中有所出现，当旧的枢纽被隐藏在网络中时。这种现象导致了网络演化和拓扑结构的变化。老化现象的例子可参照 Facebook 超越了网络中最大的中心 Google (自2000年以来最大的节点)。&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;鲁棒性和攻击容忍度 Robustness and Attack Tolerance&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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随机故障的节点或定向攻击网络关键组成部分的枢纽。在网络枢纽节点的随机失效过程中，网络的鲁棒性是由节点的随机失效决定的。&amp;lt; ref &amp;gt; { cite journal | title = Resilience of the Internet to Random breaks | &lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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日记 = 体育。牧师。李特 | &lt;br /&gt;
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year=2000|&lt;br /&gt;
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year=2000|&lt;br /&gt;
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2000年&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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1 = Reoven | &lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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最后 = Cohen | &lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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首先2 = k。2 = Erez | first3 = d.3 = ben-Avraham | first4 = s | last4 = Havlin | authorlink4 = Shlomo Havlin | &lt;br /&gt;
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volume=85|&lt;br /&gt;
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85 | &lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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页数 = 4626-8&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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Doi = 10.1103/physrvlett. 85.4626 | &lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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Http://link.aps.org/doi/10.1103/physrevlett.85.4626&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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| bibcode = 2000PhRvL. . 85.4626 c | arxiv = cond-mat/0007048 | pmid = 11082612}&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除它的几率很小。而去除小节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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在对枢纽进行有针对性的攻击时，网络的完整性会相对较快地崩溃。由于小节点主要连接到枢纽节点，对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时最大的参与者(枢纽)的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽节点可能会产生积极的影响，目标节点的消失可能会摧毁整个恐怖组织。网络的攻击容忍度可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
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==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17575</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17575"/>
		<updated>2020-10-31T11:07:17Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Emergence 成因 */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 出现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&amp;lt;ref name=RMP&amp;gt;{{Cite journal&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&amp;lt;ref name=RMP&amp;gt;{{Cite journal&lt;br /&gt;
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枢纽的成因可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。{ Cite journal&lt;br /&gt;
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 | url = http://www.nd.edu/~networks/Publication%20Categories/03%20Journal%20Articles/Physics/StatisticalMechanics_Rev%20of%20Modern%20Physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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 | url = http://www.nd.edu/~networks/Publication%20Categories/03%20Journal%20Articles/Physics/StatisticalMechanics_Rev%20of%20Modern%20Physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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Http://www.nd.edu/~networks/publication%20categories/03%20journal%20articles/physics/statisticalmechanics_rev%20of%20modern%20physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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 | authorlink1 = Réka Albert | first1 = Réka | last1 = Albert&lt;br /&gt;
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 | authorlink1 = Réka Albert | first1 = Réka | last1 = Albert&lt;br /&gt;
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1 = r é ka Albert | first1 = r é ka | last1 = Albert&lt;br /&gt;
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 | authorlink2 = Albert-László Barabási | first2 = Albert-László | last2 = Barabási&lt;br /&gt;
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 | authorlink2 = Albert-László Barabási | first2 = Albert-László | last2 = Barabási&lt;br /&gt;
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2 = albert-lászló Barabási | first2 = albert-lászló | last2 = Barabási&lt;br /&gt;
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 | title = Statistical mechanics of complex networks&lt;br /&gt;
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 | title = Statistical mechanics of complex networks&lt;br /&gt;
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| title = 复杂网络的统计力学&lt;br /&gt;
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 | journal = [[Reviews of Modern Physics]]&lt;br /&gt;
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 | journal = Reviews of Modern Physics&lt;br /&gt;
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| 杂志 = 现代物理学评论&lt;br /&gt;
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 | pages = 47–97&lt;br /&gt;
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| 页数 = 47-97&lt;br /&gt;
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 | year = 2002&lt;br /&gt;
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2002年&lt;br /&gt;
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 | doi = 10.1103/RevModPhys.74.47&lt;br /&gt;
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 | doi = 10.1103/RevModPhys.74.47&lt;br /&gt;
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10.1103/RevModPhys. 74.47&lt;br /&gt;
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 | bibcode=2002RvMP...74...47A&lt;br /&gt;
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2002RvMP... 74... 47A&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的增大。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
根据 Barabasi-Albert 模型 &amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt; 分析了网络生长的步骤]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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这个网络从一个初始的由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点构成的连接网络开始。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被连接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率是&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度数，这个和取自所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;。（分母的结果是当前网络中边的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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网络中枢纽节点的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，出现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大的互联网中心8年后，Facebook 出现了，然而在2011年，Facebook 成为了全球最大的互联网中心。因此，在实际网络中，枢纽的增长和规模也取决于各种属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽节点有几个属性&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络中的路径距离===&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽节点越多，节点之间的距离就越小。在无标度网络中，枢纽是连接度小的节点的桥梁。由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径距离的差异可能并不明显，但是在大型随机网络和无标度网络中，路径距离的差异是显著的。&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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无标度网络中的平均路径长度:&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽节点的老化 Aging of hubs (nodes)&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).{{Citation needed|date=May 2016}}&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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这种现象在真实网络中有所出现，当旧的枢纽被隐藏在网络中时。这种现象导致了网络演化和拓扑结构的变化。老化现象的例子可参照 Facebook 超越了网络中最大的中心 Google (自2000年以来最大的节点)。&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;鲁棒性和攻击容忍度 Robustness and Attack Tolerance&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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随机故障的节点或定向攻击网络关键组成部分的枢纽。在网络枢纽节点的随机失效过程中，网络的鲁棒性是由节点的随机失效决定的。&amp;lt; ref &amp;gt; { cite journal | title = Resilience of the Internet to Random breaks | &lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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日记 = 体育。牧师。李特 | &lt;br /&gt;
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year=2000|&lt;br /&gt;
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year=2000|&lt;br /&gt;
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2000年&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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1 = Reoven | &lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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最后 = Cohen | &lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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首先2 = k。2 = Erez | first3 = d.3 = ben-Avraham | first4 = s | last4 = Havlin | authorlink4 = Shlomo Havlin | &lt;br /&gt;
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volume=85|&lt;br /&gt;
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volume=85|&lt;br /&gt;
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85 | &lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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页数 = 4626-8&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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Doi = 10.1103/physrvlett. 85.4626 | &lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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Http://link.aps.org/doi/10.1103/physrevlett.85.4626&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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| bibcode = 2000PhRvL. . 85.4626 c | arxiv = cond-mat/0007048 | pmid = 11082612}&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除它的几率很小。而去除小节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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在对枢纽进行有针对性的攻击时，网络的完整性会相对较快地崩溃。由于小节点主要连接到枢纽节点，对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时最大的参与者(枢纽)的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽节点可能会产生积极的影响，目标节点的消失可能会摧毁整个恐怖组织。网络的攻击容忍度可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
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==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17574</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17574"/>
		<updated>2020-10-31T11:06:09Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点（即枢纽）具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 成因==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&amp;lt;ref name=RMP&amp;gt;{{Cite journal&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&amp;lt;ref name=RMP&amp;gt;{{Cite journal&lt;br /&gt;
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枢纽的成因可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的区别主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先链接 Preferential Attachment&amp;lt;/font&amp;gt;'''。{ Cite journal&lt;br /&gt;
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 | url = http://www.nd.edu/~networks/Publication%20Categories/03%20Journal%20Articles/Physics/StatisticalMechanics_Rev%20of%20Modern%20Physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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 | url = http://www.nd.edu/~networks/Publication%20Categories/03%20Journal%20Articles/Physics/StatisticalMechanics_Rev%20of%20Modern%20Physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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Http://www.nd.edu/~networks/publication%20categories/03%20journal%20articles/physics/statisticalmechanics_rev%20of%20modern%20physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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 | authorlink1 = Réka Albert | first1 = Réka | last1 = Albert&lt;br /&gt;
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 | authorlink1 = Réka Albert | first1 = Réka | last1 = Albert&lt;br /&gt;
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1 = r é ka Albert | first1 = r é ka | last1 = Albert&lt;br /&gt;
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 | authorlink2 = Albert-László Barabási | first2 = Albert-László | last2 = Barabási&lt;br /&gt;
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 | authorlink2 = Albert-László Barabási | first2 = Albert-László | last2 = Barabási&lt;br /&gt;
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2 = albert-lászló Barabási | first2 = albert-lászló | last2 = Barabási&lt;br /&gt;
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 | title = Statistical mechanics of complex networks&lt;br /&gt;
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 | title = Statistical mechanics of complex networks&lt;br /&gt;
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| title = 复杂网络的统计力学&lt;br /&gt;
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 | journal = [[Reviews of Modern Physics]]&lt;br /&gt;
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 | journal = Reviews of Modern Physics&lt;br /&gt;
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| 杂志 = 现代物理学评论&lt;br /&gt;
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 | volume = 74&lt;br /&gt;
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74&lt;br /&gt;
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 | pages = 47–97&lt;br /&gt;
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 | pages = 47–97&lt;br /&gt;
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| 页数 = 47-97&lt;br /&gt;
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 | year = 2002&lt;br /&gt;
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 | year = 2002&lt;br /&gt;
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2002年&lt;br /&gt;
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 | doi = 10.1103/RevModPhys.74.47&lt;br /&gt;
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 | doi = 10.1103/RevModPhys.74.47&lt;br /&gt;
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10.1103/RevModPhys. 74.47&lt;br /&gt;
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 | bibcode=2002RvMP...74...47A&lt;br /&gt;
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 | bibcode=2002RvMP...74...47A&lt;br /&gt;
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2002RvMP... 74... 47A&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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*（a）无标度网络假设节点数量''N''保持持续的增长，而随机网络则假设节点数量是固定的。在无标度网络中，最大枢纽的度随着网络规模的增大，呈多项式地上升。因此，在无标度网络中，枢纽的度可以很高。而在随机网络中，最大节点的度随''N''的增大而呈对数式（或更慢）的增大。因此即使在一个非常大的随机网络中，枢纽的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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*（b）无标度网络中的新节点倾向于链接到度较高的节点，而随机网络中的新节点则与其他节点随机相连。这一过程称为优先链接。新节点链接到度''k''较高节点的倾向可可以用幂律分布来刻画(即，富者越富)。这一想法由'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;维尔弗雷多·帕累托 Vilfredo Pareto&amp;lt;/font&amp;gt;'''提出，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的出现并不仅仅是人类行为所创造的网络的典型现象，在新陈代谢网络或疾病网络中这一现象也十分常见。&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; 这种现象可以由像Facebook或谷歌这样的万维网枢纽的来解释。这些网页是非常有名的，因此相较于指向随机的小网页，其他网页指向他们的倾向要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
根据 Barabasi-Albert 模型 &amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt; 分析了网络生长的步骤]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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这个网络从一个初始的由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点构成的连接网络开始。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
&lt;br /&gt;
每次向网络添加一个新节点。每个新的节点都被连接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率是&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
&lt;br /&gt;
其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度数，这个和取自所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;。（分母的结果是当前网络中边的两倍）。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
&lt;br /&gt;
网络中枢纽节点的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，出现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大的互联网中心8年后，Facebook 出现了，然而在2011年，Facebook 成为了全球最大的互联网中心。因此，在实际网络中，枢纽的增长和规模也取决于各种属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
&lt;br /&gt;
== Attributes 属性==&lt;br /&gt;
&lt;br /&gt;
There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
&lt;br /&gt;
There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
&lt;br /&gt;
无标度网络中的枢纽节点有几个属性&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=== Shortening the path lengths in a network 缩短网络中的路径距离===&lt;br /&gt;
&lt;br /&gt;
The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
&lt;br /&gt;
The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
&lt;br /&gt;
网络中可观察到的枢纽节点越多，节点之间的距离就越小。在无标度网络中，枢纽是连接度小的节点的桥梁。由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径距离的差异可能并不明显，但是在大型随机网络和无标度网络中，路径距离的差异是显著的。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Average path length in scale-free networks:&lt;br /&gt;
&lt;br /&gt;
Average path length in scale-free networks:&lt;br /&gt;
&lt;br /&gt;
无标度网络中的平均路径长度:&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽节点的老化 Aging of hubs (nodes)&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
&lt;br /&gt;
The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).{{Citation needed|date=May 2016}}&lt;br /&gt;
&lt;br /&gt;
The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
&lt;br /&gt;
这种现象在真实网络中有所出现，当旧的枢纽被隐藏在网络中时。这种现象导致了网络演化和拓扑结构的变化。老化现象的例子可参照 Facebook 超越了网络中最大的中心 Google (自2000年以来最大的节点)。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;鲁棒性和攻击容忍度 Robustness and Attack Tolerance&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
&lt;br /&gt;
During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
&lt;br /&gt;
During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
&lt;br /&gt;
随机故障的节点或定向攻击网络关键组成部分的枢纽。在网络枢纽节点的随机失效过程中，网络的鲁棒性是由节点的随机失效决定的。&amp;lt; ref &amp;gt; { cite journal | title = Resilience of the Internet to Random breaks | &lt;br /&gt;
&lt;br /&gt;
journal=Phys. Rev. Lett.|&lt;br /&gt;
&lt;br /&gt;
journal=Phys. Rev. Lett.|&lt;br /&gt;
&lt;br /&gt;
日记 = 体育。牧师。李特 | &lt;br /&gt;
&lt;br /&gt;
year=2000|&lt;br /&gt;
&lt;br /&gt;
year=2000|&lt;br /&gt;
&lt;br /&gt;
2000年&lt;br /&gt;
&lt;br /&gt;
first=Reoven|&lt;br /&gt;
&lt;br /&gt;
first=Reoven|&lt;br /&gt;
&lt;br /&gt;
1 = Reoven | &lt;br /&gt;
&lt;br /&gt;
last=Cohen|&lt;br /&gt;
&lt;br /&gt;
last=Cohen|&lt;br /&gt;
&lt;br /&gt;
最后 = Cohen | &lt;br /&gt;
&lt;br /&gt;
first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
&lt;br /&gt;
first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
&lt;br /&gt;
首先2 = k。2 = Erez | first3 = d.3 = ben-Avraham | first4 = s | last4 = Havlin | authorlink4 = Shlomo Havlin | &lt;br /&gt;
&lt;br /&gt;
volume=85|&lt;br /&gt;
&lt;br /&gt;
volume=85|&lt;br /&gt;
&lt;br /&gt;
85 | &lt;br /&gt;
&lt;br /&gt;
pages=4626–8|&lt;br /&gt;
&lt;br /&gt;
pages=4626–8|&lt;br /&gt;
&lt;br /&gt;
页数 = 4626-8&lt;br /&gt;
&lt;br /&gt;
doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
&lt;br /&gt;
doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
&lt;br /&gt;
Doi = 10.1103/physrvlett. 85.4626 | &lt;br /&gt;
&lt;br /&gt;
url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
&lt;br /&gt;
url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
&lt;br /&gt;
Http://link.aps.org/doi/10.1103/physrevlett.85.4626&lt;br /&gt;
&lt;br /&gt;
|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
&lt;br /&gt;
|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
&lt;br /&gt;
| bibcode = 2000PhRvL. . 85.4626 c | arxiv = cond-mat/0007048 | pmid = 11082612}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
&lt;br /&gt;
&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
&lt;br /&gt;
由于枢纽与大量小度节点共存，随机故障删除它的几率很小。而去除小节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
在对枢纽进行有针对性的攻击时，网络的完整性会相对较快地崩溃。由于小节点主要连接到枢纽节点，对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时最大的参与者(枢纽)的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽节点可能会产生积极的影响，目标节点的消失可能会摧毁整个恐怖组织。网络的攻击容忍度可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=== Degree correlation 度相关===&lt;br /&gt;
&lt;br /&gt;
The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
&lt;br /&gt;
The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
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	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17572</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17572"/>
		<updated>2020-10-31T10:43:34Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，其中枢纽被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的重要构件。与网络中的其他节点相比，枢纽拥有的链接数量明显更多。在保持网络规模''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下，无标度网络中枢纽拥有的链接数（度）远远高于随机网络中链接数最大的节点。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，对于每个节点而言，度''k''是相当的，因此不可能出现枢纽节点。而在无标度网络中，少数节点(即枢纽)具有较高的度值 ''k''，而其他节点则只拥有少量的链接。&lt;br /&gt;
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== Emergence 出现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
图3：随机网络（a），无标度网络（b）。在无标度网络中，大型枢纽被突出显示。]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&amp;lt;ref name=RMP&amp;gt;{{Cite journal&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&amp;lt;ref name=RMP&amp;gt;{{Cite journal&lt;br /&gt;
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枢纽的出现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks&amp;lt;/font&amp;gt;'''（Barabási-Albert模型）与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks&amp;lt;/font&amp;gt;'''（Erdős–Rényi model）的不同主要存在于如下两个方面: （a）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，（b）'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先连接 Preferential Attachment&amp;lt;/font&amp;gt;'''。{ Cite journal&lt;br /&gt;
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 | url = http://www.nd.edu/~networks/Publication%20Categories/03%20Journal%20Articles/Physics/StatisticalMechanics_Rev%20of%20Modern%20Physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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 | url = http://www.nd.edu/~networks/Publication%20Categories/03%20Journal%20Articles/Physics/StatisticalMechanics_Rev%20of%20Modern%20Physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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Http://www.nd.edu/~networks/publication%20categories/03%20journal%20articles/physics/statisticalmechanics_rev%20of%20modern%20physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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 | authorlink1 = Réka Albert | first1 = Réka | last1 = Albert&lt;br /&gt;
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 | authorlink1 = Réka Albert | first1 = Réka | last1 = Albert&lt;br /&gt;
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1 = r é ka Albert | first1 = r é ka | last1 = Albert&lt;br /&gt;
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 | authorlink2 = Albert-László Barabási | first2 = Albert-László | last2 = Barabási&lt;br /&gt;
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 | authorlink2 = Albert-László Barabási | first2 = Albert-László | last2 = Barabási&lt;br /&gt;
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2 = albert-lászló Barabási | first2 = albert-lászló | last2 = Barabási&lt;br /&gt;
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 | title = Statistical mechanics of complex networks&lt;br /&gt;
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 | title = Statistical mechanics of complex networks&lt;br /&gt;
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| title = 复杂网络的统计力学&lt;br /&gt;
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 | journal = [[Reviews of Modern Physics]]&lt;br /&gt;
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 | journal = Reviews of Modern Physics&lt;br /&gt;
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| 杂志 = 现代物理学评论&lt;br /&gt;
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 | volume = 74&lt;br /&gt;
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 | volume = 74&lt;br /&gt;
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74&lt;br /&gt;
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 | pages = 47–97&lt;br /&gt;
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 | pages = 47–97&lt;br /&gt;
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| 页数 = 47-97&lt;br /&gt;
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 | year = 2002&lt;br /&gt;
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 | year = 2002&lt;br /&gt;
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2002年&lt;br /&gt;
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 | doi = 10.1103/RevModPhys.74.47&lt;br /&gt;
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 | doi = 10.1103/RevModPhys.74.47&lt;br /&gt;
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10.1103/RevModPhys. 74.47&lt;br /&gt;
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 | bibcode=2002RvMP...74...47A&lt;br /&gt;
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 | bibcode=2002RvMP...74...47A&lt;br /&gt;
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2002RvMP... 74... 47A&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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无标度网络假设节点数“N”持续增长，而随机网络假设节点数为固定数目。在无标度网络中，最大枢纽节点的度数随着网络的大小而多项式地上升。因此，在无标度网络中，枢纽节点的度数可以很高。在随机网络中，最大节点的度数随着N的增大而呈线性增大(或变慢)，因此即使在一个非常大的随机网络中，枢纽节点的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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无标度网络中的新节点，与随机网络中的新节点相比，更倾向于连接到具有更高度的节点。这个过程称为优先依附。新节点连接到高度值''k''节点的趋势可被看做幂律分布(也被称作，越富有就越富有的过程)。这个想法是由Vilfredo Pareto提出的，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的不仅是符合的人类活动网络，也可以拟合包括代谢网络或疾病网络。这种现象可以用像Facebook或谷歌这样的万维网中心的例子来解释。这些网页是非常有名的，因此其他网页指向他们的倾向比指向到随机的小网页要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert 模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
根据 Barabasi-Albert 模型 &amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt; 分析了网络生长的步骤]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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这个网络从一个初始的由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点构成的连接网络开始。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被连接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率是&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度数，这个和取自所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;。（分母的结果是当前网络中边的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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网络中枢纽节点的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，出现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大的互联网中心8年后，Facebook 出现了，然而在2011年，Facebook 成为了全球最大的互联网中心。因此，在实际网络中，枢纽的增长和规模也取决于各种属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽节点有几个属性&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络中的路径距离===&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽节点越多，节点之间的距离就越小。在无标度网络中，枢纽是连接度小的节点的桥梁。由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径距离的差异可能并不明显，但是在大型随机网络和无标度网络中，路径距离的差异是显著的。&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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无标度网络中的平均路径长度:&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽节点的老化 Aging of hubs (nodes)&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).{{Citation needed|date=May 2016}}&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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这种现象在真实网络中有所出现，当旧的枢纽被隐藏在网络中时。这种现象导致了网络演化和拓扑结构的变化。老化现象的例子可参照 Facebook 超越了网络中最大的中心 Google (自2000年以来最大的节点)。&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;鲁棒性和攻击容忍度 Robustness and Attack Tolerance&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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随机故障的节点或定向攻击网络关键组成部分的枢纽。在网络枢纽节点的随机失效过程中，网络的鲁棒性是由节点的随机失效决定的。&amp;lt; ref &amp;gt; { cite journal | title = Resilience of the Internet to Random breaks | &lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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日记 = 体育。牧师。李特 | &lt;br /&gt;
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year=2000|&lt;br /&gt;
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year=2000|&lt;br /&gt;
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2000年&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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1 = Reoven | &lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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最后 = Cohen | &lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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首先2 = k。2 = Erez | first3 = d.3 = ben-Avraham | first4 = s | last4 = Havlin | authorlink4 = Shlomo Havlin | &lt;br /&gt;
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volume=85|&lt;br /&gt;
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volume=85|&lt;br /&gt;
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85 | &lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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页数 = 4626-8&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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Doi = 10.1103/physrvlett. 85.4626 | &lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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Http://link.aps.org/doi/10.1103/physrevlett.85.4626&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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| bibcode = 2000PhRvL. . 85.4626 c | arxiv = cond-mat/0007048 | pmid = 11082612}&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除它的几率很小。而去除小节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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在对枢纽进行有针对性的攻击时，网络的完整性会相对较快地崩溃。由于小节点主要连接到枢纽节点，对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时最大的参与者(枢纽)的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽节点可能会产生积极的影响，目标节点的消失可能会摧毁整个恐怖组织。网络的攻击容忍度可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
&lt;br /&gt;
The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
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==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17433</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17433"/>
		<updated>2020-10-30T06:38:38Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
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{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
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图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
图1：大脑连接性的网络表示，其中枢纽节点被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
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图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
图2：2005年1月15日的因特网局部图，枢纽节点被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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枢纽是拥有大度节点网络的一个组成部分。与网络中的其他节点相比，枢纽的链接数要大得多。无标度网络中枢纽的链接数（度）远远高于随机网络中链接数最大的节点，在保持网络的大小''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，每个节点的度''k''是可比的，因此不可能出现枢纽节点。在无标度网络中，少数节点(即枢纽节点)具有高度值 ''k''，而其他节点只有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
随机网络（a）和无标度网络（b），在无标度网络中，大型枢纽被突出显示]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&amp;lt;ref name=RMP&amp;gt;{{Cite journal&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&amp;lt;ref name=RMP&amp;gt;{{Cite journal&lt;br /&gt;
&lt;br /&gt;
枢纽节点的出现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks Barabási-Albert model&amp;lt;/font&amp;gt;'''与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks Erdős–Rényi model&amp;lt;/font&amp;gt;'''在两个方面有所不同: (a)'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，(b)'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先连接 Preferential Attachment&amp;lt;/font&amp;gt;'''。{ Cite journal&lt;br /&gt;
&lt;br /&gt;
 | url = http://www.nd.edu/~networks/Publication%20Categories/03%20Journal%20Articles/Physics/StatisticalMechanics_Rev%20of%20Modern%20Physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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 | url = http://www.nd.edu/~networks/Publication%20Categories/03%20Journal%20Articles/Physics/StatisticalMechanics_Rev%20of%20Modern%20Physics%2074,%2047%20(2002).pdf&lt;br /&gt;
&lt;br /&gt;
Http://www.nd.edu/~networks/publication%20categories/03%20journal%20articles/physics/statisticalmechanics_rev%20of%20modern%20physics%2074,%2047%20(2002).pdf&lt;br /&gt;
&lt;br /&gt;
 | authorlink1 = Réka Albert | first1 = Réka | last1 = Albert&lt;br /&gt;
&lt;br /&gt;
 | authorlink1 = Réka Albert | first1 = Réka | last1 = Albert&lt;br /&gt;
&lt;br /&gt;
1 = r é ka Albert | first1 = r é ka | last1 = Albert&lt;br /&gt;
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 | authorlink2 = Albert-László Barabási | first2 = Albert-László | last2 = Barabási&lt;br /&gt;
&lt;br /&gt;
 | authorlink2 = Albert-László Barabási | first2 = Albert-László | last2 = Barabási&lt;br /&gt;
&lt;br /&gt;
2 = albert-lászló Barabási | first2 = albert-lászló | last2 = Barabási&lt;br /&gt;
&lt;br /&gt;
 | title = Statistical mechanics of complex networks&lt;br /&gt;
&lt;br /&gt;
 | title = Statistical mechanics of complex networks&lt;br /&gt;
&lt;br /&gt;
| title = 复杂网络的统计力学&lt;br /&gt;
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 | journal = [[Reviews of Modern Physics]]&lt;br /&gt;
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 | journal = Reviews of Modern Physics&lt;br /&gt;
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| 杂志 = 现代物理学评论&lt;br /&gt;
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 | volume = 74&lt;br /&gt;
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 | volume = 74&lt;br /&gt;
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74&lt;br /&gt;
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 | pages = 47–97&lt;br /&gt;
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 | pages = 47–97&lt;br /&gt;
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| 页数 = 47-97&lt;br /&gt;
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 | year = 2002&lt;br /&gt;
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 | year = 2002&lt;br /&gt;
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2002年&lt;br /&gt;
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 | doi = 10.1103/RevModPhys.74.47&lt;br /&gt;
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 | doi = 10.1103/RevModPhys.74.47&lt;br /&gt;
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10.1103/RevModPhys. 74.47&lt;br /&gt;
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 | bibcode=2002RvMP...74...47A&lt;br /&gt;
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 | bibcode=2002RvMP...74...47A&lt;br /&gt;
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2002RvMP... 74... 47A&lt;br /&gt;
&lt;br /&gt;
|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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无标度网络假设节点数“N”持续增长，而随机网络假设节点数为固定数目。在无标度网络中，最大枢纽节点的度数随着网络的大小而多项式地上升。因此，在无标度网络中，枢纽节点的度数可以很高。在随机网络中，最大节点的度数随着N的增大而呈线性增大(或变慢)，因此即使在一个非常大的随机网络中，枢纽节点的数量也会很小。&lt;br /&gt;
&lt;br /&gt;
* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
&lt;br /&gt;
无标度网络中的新节点，与随机网络中的新节点相比，更倾向于连接到具有更高度的节点。这个过程称为优先依附。新节点连接到高度值''k''节点的趋势可被看做幂律分布(也被称作，越富有就越富有的过程)。这个想法是由Vilfredo Pareto提出的，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的不仅是符合的人类活动网络，也可以拟合包括代谢网络或疾病网络。这种现象可以用像Facebook或谷歌这样的万维网中心的例子来解释。这些网页是非常有名的，因此其他网页指向他们的倾向比指向到随机的小网页要高得多。&lt;br /&gt;
&lt;br /&gt;
The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
&lt;br /&gt;
The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
&lt;br /&gt;
Barabási-Albert 模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
根据 Barabasi-Albert 模型 &amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt; 分析了网络生长的步骤]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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这个网络从一个初始的由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点构成的连接网络开始。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被连接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率是&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度数，这个和取自所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;。（分母的结果是当前网络中边的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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网络中枢纽节点的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，出现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大的互联网中心8年后，Facebook 出现了，然而在2011年，Facebook 成为了全球最大的互联网中心。因此，在实际网络中，枢纽的增长和规模也取决于各种属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽节点有几个属性&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络中的路径距离===&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
&lt;br /&gt;
The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽节点越多，节点之间的距离就越小。在无标度网络中，枢纽是连接度小的节点的桥梁。由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径距离的差异可能并不明显，但是在大型随机网络和无标度网络中，路径距离的差异是显著的。&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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无标度网络中的平均路径长度:&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽节点的老化 Aging of hubs (nodes)&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).{{Citation needed|date=May 2016}}&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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这种现象在真实网络中有所出现，当旧的枢纽被隐藏在网络中时。这种现象导致了网络演化和拓扑结构的变化。老化现象的例子可参照 Facebook 超越了网络中最大的中心 Google (自2000年以来最大的节点)。&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;鲁棒性和攻击容忍度 Robustness and Attack Tolerance&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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随机故障的节点或定向攻击网络关键组成部分的枢纽。在网络枢纽节点的随机失效过程中，网络的鲁棒性是由节点的随机失效决定的。&amp;lt; ref &amp;gt; { cite journal | title = Resilience of the Internet to Random breaks | &lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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日记 = 体育。牧师。李特 | &lt;br /&gt;
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year=2000|&lt;br /&gt;
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year=2000|&lt;br /&gt;
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2000年&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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1 = Reoven | &lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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最后 = Cohen | &lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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首先2 = k。2 = Erez | first3 = d.3 = ben-Avraham | first4 = s | last4 = Havlin | authorlink4 = Shlomo Havlin | &lt;br /&gt;
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volume=85|&lt;br /&gt;
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volume=85|&lt;br /&gt;
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85 | &lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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页数 = 4626-8&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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Doi = 10.1103/physrvlett. 85.4626 | &lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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Http://link.aps.org/doi/10.1103/physrevlett.85.4626&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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| bibcode = 2000PhRvL. . 85.4626 c | arxiv = cond-mat/0007048 | pmid = 11082612}&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除它的几率很小。而去除小节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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在对枢纽进行有针对性的攻击时，网络的完整性会相对较快地崩溃。由于小节点主要连接到枢纽节点，对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时最大的参与者(枢纽)的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽节点可能会产生积极的影响，目标节点的消失可能会摧毁整个恐怖组织。网络的攻击容忍度可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
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==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17432</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17432"/>
		<updated>2020-10-30T06:31:30Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* References */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
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{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
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图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
表示大脑连接性的网络，其中枢纽节点被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
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图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
2005年1月15日的因特网局部图，枢纽节点被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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一个枢纽节点是网络中具有高度值的组件。与网络中的其他节点相比，枢纽节点的链接数要大得多。无尺度网络中枢纽的链接数(度)远远高于随机网络中链接数最大的节点，在保持网络的大小''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，每个节点的度''k''是可比的，因此不可能出现枢纽节点。在无标度网络中，少数节点(即枢纽节点)具有高度值 ''k''，而其他节点只有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
随机网络（a）和无标度网络（b），在无标度网络中，大型枢纽被突出显示]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&amp;lt;ref name=RMP&amp;gt;{{Cite journal&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&amp;lt;ref name=RMP&amp;gt;{{Cite journal&lt;br /&gt;
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枢纽节点的出现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks Barabási-Albert model&amp;lt;/font&amp;gt;'''与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks Erdős–Rényi model&amp;lt;/font&amp;gt;'''在两个方面有所不同: (a)'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，(b)'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先连接 Preferential Attachment&amp;lt;/font&amp;gt;'''。{ Cite journal&lt;br /&gt;
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 | url = http://www.nd.edu/~networks/Publication%20Categories/03%20Journal%20Articles/Physics/StatisticalMechanics_Rev%20of%20Modern%20Physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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 | url = http://www.nd.edu/~networks/Publication%20Categories/03%20Journal%20Articles/Physics/StatisticalMechanics_Rev%20of%20Modern%20Physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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Http://www.nd.edu/~networks/publication%20categories/03%20journal%20articles/physics/statisticalmechanics_rev%20of%20modern%20physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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 | authorlink1 = Réka Albert | first1 = Réka | last1 = Albert&lt;br /&gt;
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 | authorlink1 = Réka Albert | first1 = Réka | last1 = Albert&lt;br /&gt;
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1 = r é ka Albert | first1 = r é ka | last1 = Albert&lt;br /&gt;
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 | authorlink2 = Albert-László Barabási | first2 = Albert-László | last2 = Barabási&lt;br /&gt;
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 | authorlink2 = Albert-László Barabási | first2 = Albert-László | last2 = Barabási&lt;br /&gt;
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2 = albert-lászló Barabási | first2 = albert-lászló | last2 = Barabási&lt;br /&gt;
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 | title = Statistical mechanics of complex networks&lt;br /&gt;
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 | title = Statistical mechanics of complex networks&lt;br /&gt;
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| title = 复杂网络的统计力学&lt;br /&gt;
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 | journal = [[Reviews of Modern Physics]]&lt;br /&gt;
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 | journal = Reviews of Modern Physics&lt;br /&gt;
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| 杂志 = 现代物理学评论&lt;br /&gt;
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 | volume = 74&lt;br /&gt;
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| 页数 = 47-97&lt;br /&gt;
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2002年&lt;br /&gt;
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 | doi = 10.1103/RevModPhys.74.47&lt;br /&gt;
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 | doi = 10.1103/RevModPhys.74.47&lt;br /&gt;
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10.1103/RevModPhys. 74.47&lt;br /&gt;
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 | bibcode=2002RvMP...74...47A&lt;br /&gt;
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2002RvMP... 74... 47A&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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无标度网络假设节点数“N”持续增长，而随机网络假设节点数为固定数目。在无标度网络中，最大枢纽节点的度数随着网络的大小而多项式地上升。因此，在无标度网络中，枢纽节点的度数可以很高。在随机网络中，最大节点的度数随着N的增大而呈线性增大(或变慢)，因此即使在一个非常大的随机网络中，枢纽节点的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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无标度网络中的新节点，与随机网络中的新节点相比，更倾向于连接到具有更高度的节点。这个过程称为优先依附。新节点连接到高度值''k''节点的趋势可被看做幂律分布(也被称作，越富有就越富有的过程)。这个想法是由Vilfredo Pareto提出的，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的不仅是符合的人类活动网络，也可以拟合包括代谢网络或疾病网络。这种现象可以用像Facebook或谷歌这样的万维网中心的例子来解释。这些网页是非常有名的，因此其他网页指向他们的倾向比指向到随机的小网页要高得多。&lt;br /&gt;
&lt;br /&gt;
The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
&lt;br /&gt;
The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert 模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
根据 Barabasi-Albert 模型 &amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt; 分析了网络生长的步骤]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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这个网络从一个初始的由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点构成的连接网络开始。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被连接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率是&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度数，这个和取自所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;。（分母的结果是当前网络中边的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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网络中枢纽节点的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，出现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大的互联网中心8年后，Facebook 出现了，然而在2011年，Facebook 成为了全球最大的互联网中心。因此，在实际网络中，枢纽的增长和规模也取决于各种属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽节点有几个属性&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络中的路径距离===&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽节点越多，节点之间的距离就越小。在无标度网络中，枢纽是连接度小的节点的桥梁。由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径距离的差异可能并不明显，但是在大型随机网络和无标度网络中，路径距离的差异是显著的。&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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无标度网络中的平均路径长度:&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽节点的老化 Aging of hubs (nodes)&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).{{Citation needed|date=May 2016}}&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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这种现象在真实网络中有所出现，当旧的枢纽被隐藏在网络中时。这种现象导致了网络演化和拓扑结构的变化。老化现象的例子可参照 Facebook 超越了网络中最大的中心 Google (自2000年以来最大的节点)。&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;鲁棒性和攻击容忍度 Robustness and Attack Tolerance&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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随机故障的节点或定向攻击网络关键组成部分的枢纽。在网络枢纽节点的随机失效过程中，网络的鲁棒性是由节点的随机失效决定的。&amp;lt; ref &amp;gt; { cite journal | title = Resilience of the Internet to Random breaks | &lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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日记 = 体育。牧师。李特 | &lt;br /&gt;
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year=2000|&lt;br /&gt;
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year=2000|&lt;br /&gt;
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2000年&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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1 = Reoven | &lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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最后 = Cohen | &lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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首先2 = k。2 = Erez | first3 = d.3 = ben-Avraham | first4 = s | last4 = Havlin | authorlink4 = Shlomo Havlin | &lt;br /&gt;
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volume=85|&lt;br /&gt;
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volume=85|&lt;br /&gt;
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85 | &lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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页数 = 4626-8&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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Doi = 10.1103/physrvlett. 85.4626 | &lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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Http://link.aps.org/doi/10.1103/physrevlett.85.4626&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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| bibcode = 2000PhRvL. . 85.4626 c | arxiv = cond-mat/0007048 | pmid = 11082612}&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除它的几率很小。而去除小节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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在对枢纽进行有针对性的攻击时，网络的完整性会相对较快地崩溃。由于小节点主要连接到枢纽节点，对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时最大的参与者(枢纽)的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽节点可能会产生积极的影响，目标节点的消失可能会摧毁整个恐怖组织。网络的攻击容忍度可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
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==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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分类: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17431</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17431"/>
		<updated>2020-10-30T06:30:12Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Emergence 涌现 */&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
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{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
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图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
表示大脑连接性的网络，其中枢纽节点被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
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图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
2005年1月15日的因特网局部图，枢纽节点被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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一个枢纽节点是网络中具有高度值的组件。与网络中的其他节点相比，枢纽节点的链接数要大得多。无尺度网络中枢纽的链接数(度)远远高于随机网络中链接数最大的节点，在保持网络的大小''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，每个节点的度''k''是可比的，因此不可能出现枢纽节点。在无标度网络中，少数节点(即枢纽节点)具有高度值 ''k''，而其他节点只有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
随机网络（a）和无标度网络（b），在无标度网络中，大型枢纽被突出显示]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&amp;lt;ref name=RMP&amp;gt;{{Cite journal&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&amp;lt;ref name=RMP&amp;gt;{{Cite journal&lt;br /&gt;
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枢纽节点的出现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks Barabási-Albert model&amp;lt;/font&amp;gt;'''与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks Erdős–Rényi model&amp;lt;/font&amp;gt;'''在两个方面有所不同: (a)'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，(b)'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先连接 Preferential Attachment&amp;lt;/font&amp;gt;'''。{ Cite journal&lt;br /&gt;
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 | url = http://www.nd.edu/~networks/Publication%20Categories/03%20Journal%20Articles/Physics/StatisticalMechanics_Rev%20of%20Modern%20Physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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 | url = http://www.nd.edu/~networks/Publication%20Categories/03%20Journal%20Articles/Physics/StatisticalMechanics_Rev%20of%20Modern%20Physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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Http://www.nd.edu/~networks/publication%20categories/03%20journal%20articles/physics/statisticalmechanics_rev%20of%20modern%20physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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 | authorlink1 = Réka Albert | first1 = Réka | last1 = Albert&lt;br /&gt;
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 | authorlink1 = Réka Albert | first1 = Réka | last1 = Albert&lt;br /&gt;
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1 = r é ka Albert | first1 = r é ka | last1 = Albert&lt;br /&gt;
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 | authorlink2 = Albert-László Barabási | first2 = Albert-László | last2 = Barabási&lt;br /&gt;
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 | authorlink2 = Albert-László Barabási | first2 = Albert-László | last2 = Barabási&lt;br /&gt;
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2 = albert-lászló Barabási | first2 = albert-lászló | last2 = Barabási&lt;br /&gt;
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 | title = Statistical mechanics of complex networks&lt;br /&gt;
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 | title = Statistical mechanics of complex networks&lt;br /&gt;
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| title = 复杂网络的统计力学&lt;br /&gt;
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 | journal = [[Reviews of Modern Physics]]&lt;br /&gt;
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 | journal = Reviews of Modern Physics&lt;br /&gt;
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| 杂志 = 现代物理学评论&lt;br /&gt;
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 | volume = 74&lt;br /&gt;
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 | pages = 47–97&lt;br /&gt;
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 | pages = 47–97&lt;br /&gt;
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| 页数 = 47-97&lt;br /&gt;
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 | year = 2002&lt;br /&gt;
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2002年&lt;br /&gt;
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 | doi = 10.1103/RevModPhys.74.47&lt;br /&gt;
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 | doi = 10.1103/RevModPhys.74.47&lt;br /&gt;
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10.1103/RevModPhys. 74.47&lt;br /&gt;
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 | bibcode=2002RvMP...74...47A&lt;br /&gt;
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2002RvMP... 74... 47A&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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无标度网络假设节点数“N”持续增长，而随机网络假设节点数为固定数目。在无标度网络中，最大枢纽节点的度数随着网络的大小而多项式地上升。因此，在无标度网络中，枢纽节点的度数可以很高。在随机网络中，最大节点的度数随着N的增大而呈线性增大(或变慢)，因此即使在一个非常大的随机网络中，枢纽节点的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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无标度网络中的新节点，与随机网络中的新节点相比，更倾向于连接到具有更高度的节点。这个过程称为优先依附。新节点连接到高度值''k''节点的趋势可被看做幂律分布(也被称作，越富有就越富有的过程)。这个想法是由Vilfredo Pareto提出的，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的不仅是符合的人类活动网络，也可以拟合包括代谢网络或疾病网络。这种现象可以用像Facebook或谷歌这样的万维网中心的例子来解释。这些网页是非常有名的，因此其他网页指向他们的倾向比指向到随机的小网页要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert 模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
根据 Barabasi-Albert 模型 &amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt; 分析了网络生长的步骤]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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这个网络从一个初始的由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点构成的连接网络开始。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被连接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率是&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
&lt;br /&gt;
where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
&lt;br /&gt;
其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度数，这个和取自所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;。（分母的结果是当前网络中边的两倍）。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
&lt;br /&gt;
Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
&lt;br /&gt;
网络中枢纽节点的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，出现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大的互联网中心8年后，Facebook 出现了，然而在2011年，Facebook 成为了全球最大的互联网中心。因此，在实际网络中，枢纽的增长和规模也取决于各种属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
&lt;br /&gt;
== Attributes 属性==&lt;br /&gt;
&lt;br /&gt;
There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
&lt;br /&gt;
There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
&lt;br /&gt;
无标度网络中的枢纽节点有几个属性&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=== Shortening the path lengths in a network 缩短网络中的路径距离===&lt;br /&gt;
&lt;br /&gt;
The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
&lt;br /&gt;
The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
&lt;br /&gt;
网络中可观察到的枢纽节点越多，节点之间的距离就越小。在无标度网络中，枢纽是连接度小的节点的桥梁。由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径距离的差异可能并不明显，但是在大型随机网络和无标度网络中，路径距离的差异是显著的。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Average path length in scale-free networks:&lt;br /&gt;
&lt;br /&gt;
Average path length in scale-free networks:&lt;br /&gt;
&lt;br /&gt;
无标度网络中的平均路径长度:&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽节点的老化 Aging of hubs (nodes)&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
&lt;br /&gt;
The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).{{Citation needed|date=May 2016}}&lt;br /&gt;
&lt;br /&gt;
The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
&lt;br /&gt;
这种现象在真实网络中有所出现，当旧的枢纽被隐藏在网络中时。这种现象导致了网络演化和拓扑结构的变化。老化现象的例子可参照 Facebook 超越了网络中最大的中心 Google (自2000年以来最大的节点)。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;鲁棒性和攻击容忍度 Robustness and Attack Tolerance&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
&lt;br /&gt;
During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
&lt;br /&gt;
During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
&lt;br /&gt;
随机故障的节点或定向攻击网络关键组成部分的枢纽。在网络枢纽节点的随机失效过程中，网络的鲁棒性是由节点的随机失效决定的。&amp;lt; ref &amp;gt; { cite journal | title = Resilience of the Internet to Random breaks | &lt;br /&gt;
&lt;br /&gt;
journal=Phys. Rev. Lett.|&lt;br /&gt;
&lt;br /&gt;
journal=Phys. Rev. Lett.|&lt;br /&gt;
&lt;br /&gt;
日记 = 体育。牧师。李特 | &lt;br /&gt;
&lt;br /&gt;
year=2000|&lt;br /&gt;
&lt;br /&gt;
year=2000|&lt;br /&gt;
&lt;br /&gt;
2000年&lt;br /&gt;
&lt;br /&gt;
first=Reoven|&lt;br /&gt;
&lt;br /&gt;
first=Reoven|&lt;br /&gt;
&lt;br /&gt;
1 = Reoven | &lt;br /&gt;
&lt;br /&gt;
last=Cohen|&lt;br /&gt;
&lt;br /&gt;
last=Cohen|&lt;br /&gt;
&lt;br /&gt;
最后 = Cohen | &lt;br /&gt;
&lt;br /&gt;
first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
&lt;br /&gt;
first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
&lt;br /&gt;
首先2 = k。2 = Erez | first3 = d.3 = ben-Avraham | first4 = s | last4 = Havlin | authorlink4 = Shlomo Havlin | &lt;br /&gt;
&lt;br /&gt;
volume=85|&lt;br /&gt;
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volume=85|&lt;br /&gt;
&lt;br /&gt;
85 | &lt;br /&gt;
&lt;br /&gt;
pages=4626–8|&lt;br /&gt;
&lt;br /&gt;
pages=4626–8|&lt;br /&gt;
&lt;br /&gt;
页数 = 4626-8&lt;br /&gt;
&lt;br /&gt;
doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
&lt;br /&gt;
doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
&lt;br /&gt;
Doi = 10.1103/physrvlett. 85.4626 | &lt;br /&gt;
&lt;br /&gt;
url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
&lt;br /&gt;
url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
&lt;br /&gt;
Http://link.aps.org/doi/10.1103/physrevlett.85.4626&lt;br /&gt;
&lt;br /&gt;
|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
&lt;br /&gt;
|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
&lt;br /&gt;
| bibcode = 2000PhRvL. . 85.4626 c | arxiv = cond-mat/0007048 | pmid = 11082612}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
&lt;br /&gt;
&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
&lt;br /&gt;
由于枢纽与大量小度节点共存，随机故障删除它的几率很小。而去除小节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
在对枢纽进行有针对性的攻击时，网络的完整性会相对较快地崩溃。由于小节点主要连接到枢纽节点，对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时最大的参与者(枢纽)的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽节点可能会产生积极的影响，目标节点的消失可能会摧毁整个恐怖组织。网络的攻击容忍度可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=== Degree correlation 度相关===&lt;br /&gt;
&lt;br /&gt;
The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
&lt;br /&gt;
The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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范畴: 网络理论&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17430</id>
		<title>枢纽</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E6%9E%A2%E7%BA%BD&amp;diff=17430"/>
		<updated>2020-10-30T06:25:25Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：&lt;/p&gt;
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&lt;div&gt;本词条由Ryan初步翻译，已由Alienxj审校。&lt;br /&gt;
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{{redirect|Network hub|the Ethernet technology|Ethernet hub}}&lt;br /&gt;
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In [[network science]], a '''hub''' is a [[Node (networking)|node]] with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; While hubs cannot be observed in a random network, they are expected to emerge in [[scale-free network]]s. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the [[network topology]]. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as Brain Network or Internet.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络科学 Network Science&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽 Hub&amp;lt;/font&amp;gt;'''指的是其链接数远超过平均值的节点。网络的'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度性质 Scale-Free Property&amp;lt;/font&amp;gt;'''是枢纽出现的主要原因。&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf Barabási, Albert-László. ''Network Science: Graph Theory''., p. 27]&amp;lt;/ref&amp;gt; 虽然在随机网络中难以观察到枢纽，但它们却有望出现于无标度网络中。无标度网络中枢纽的出现与其'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;幂律分布 Power-Law Distribution&amp;lt;/font&amp;gt;'''的性质有关。枢纽对网络的拓扑结构有着重要的影响。我们可以在很多真实的网络中发现枢纽，比如大脑网络或者因特网。&lt;br /&gt;
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[[File:Network representation of brain connectivity.JPG|thumb|right|&lt;br /&gt;
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图1：Network representation of brain connectivity. Hubs are highlighted &lt;br /&gt;
表示大脑连接性的网络，其中枢纽节点被突出显示]]&lt;br /&gt;
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[[File:Internet map 4096.png|thumb|150px|right|&lt;br /&gt;
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图2:Partial map of the Internet based on the January 15, 2005. Hubs are highlighted &lt;br /&gt;
2005年1月15日的因特网局部图，枢纽节点被突出显示]]&lt;br /&gt;
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A hub is a component of a network with a high-degree [[Vertex (graph theory)|node]]. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links ([[Degree (graph theory)|degrees]]) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size ''N'' of the network and average degree ''&amp;lt;k&amp;gt;'' constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree ''k'' is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree ''k'' while the other nodes have a small number of links.&lt;br /&gt;
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A hub is a component of a network with a high-degree node. Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree &amp;lt;k&amp;gt; constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links.&lt;br /&gt;
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一个枢纽节点是网络中具有高度值的组件。与网络中的其他节点相比，枢纽节点的链接数要大得多。无尺度网络中枢纽的链接数(度)远远高于随机网络中链接数最大的节点，在保持网络的大小''N''和平均度 ''&amp;lt;k&amp;gt;''不变的情况下。枢纽的存在是随机网络和无标度网络的最大区别。在随机网络中，每个节点的度''k''是可比的，因此不可能出现枢纽节点。在无标度网络中，少数节点(即枢纽节点)具有高度值 ''k''，而其他节点只有少量的链接。&lt;br /&gt;
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== Emergence 涌现==&lt;br /&gt;
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[[Image:Scale-free network sample.png|thumb|Example of a random network and a scale-free network|400px|right|&lt;br /&gt;
图3：Random network (a) and scale-free network (b). In the scale-free network, the larger hubs are highlighted. &lt;br /&gt;
随机网络（a）和无标度网络（b），在无标度网络中，大型枢纽被突出显示]]&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks ([[Barabási–Albert model]]) are different from random networks ([[Erdős–Rényi model]]) in two aspects: (a) growth, (b) preferential attachment.&amp;lt;ref name=RMP&amp;gt;{{Cite journal&lt;br /&gt;
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Emergence of hubs can be explained by the difference between scale-free networks and random networks. Scale-free networks (Barabási–Albert model) are different from random networks (Erdős–Rényi model) in two aspects: (a) growth, (b) preferential attachment.&amp;lt;ref name=RMP&amp;gt;{{Cite journal&lt;br /&gt;
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枢纽节点的出现可以用无标度网络和随机网络的区别来解释。'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;无标度网络 Scale-Free Networks Barabási-Albert model&amp;lt;/font&amp;gt;'''与'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;随机网络 Random Networks Erdős–Rényi model&amp;lt;/font&amp;gt;'''在两个方面有所不同: (a)'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;增长 Growth&amp;lt;/font&amp;gt;'''，(b)'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;优先连接 Preferential Attachment&amp;lt;/font&amp;gt;'''。{ Cite journal&lt;br /&gt;
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 | url = http://www.nd.edu/~networks/Publication%20Categories/03%20Journal%20Articles/Physics/StatisticalMechanics_Rev%20of%20Modern%20Physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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 | url = http://www.nd.edu/~networks/Publication%20Categories/03%20Journal%20Articles/Physics/StatisticalMechanics_Rev%20of%20Modern%20Physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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Http://www.nd.edu/~networks/publication%20categories/03%20journal%20articles/physics/statisticalmechanics_rev%20of%20modern%20physics%2074,%2047%20(2002).pdf&lt;br /&gt;
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 | authorlink1 = Réka Albert | first1 = Réka | last1 = Albert&lt;br /&gt;
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 | authorlink1 = Réka Albert | first1 = Réka | last1 = Albert&lt;br /&gt;
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1 = r é ka Albert | first1 = r é ka | last1 = Albert&lt;br /&gt;
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 | authorlink2 = Albert-László Barabási | first2 = Albert-László | last2 = Barabási&lt;br /&gt;
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 | authorlink2 = Albert-László Barabási | first2 = Albert-László | last2 = Barabási&lt;br /&gt;
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2 = albert-lászló Barabási | first2 = albert-lászló | last2 = Barabási&lt;br /&gt;
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 | title = Statistical mechanics of complex networks&lt;br /&gt;
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 | title = Statistical mechanics of complex networks&lt;br /&gt;
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| title = 复杂网络的统计力学&lt;br /&gt;
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 | journal = [[Reviews of Modern Physics]]&lt;br /&gt;
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 | journal = Reviews of Modern Physics&lt;br /&gt;
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| 杂志 = 现代物理学评论&lt;br /&gt;
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 | volume = 74&lt;br /&gt;
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 | volume = 74&lt;br /&gt;
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74&lt;br /&gt;
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 | pages = 47–97&lt;br /&gt;
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 | pages = 47–97&lt;br /&gt;
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| 页数 = 47-97&lt;br /&gt;
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 | year = 2002&lt;br /&gt;
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 | year = 2002&lt;br /&gt;
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2002年&lt;br /&gt;
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 | doi = 10.1103/RevModPhys.74.47&lt;br /&gt;
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 | doi = 10.1103/RevModPhys.74.47&lt;br /&gt;
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10.1103/RevModPhys. 74.47&lt;br /&gt;
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 | bibcode=2002RvMP...74...47A&lt;br /&gt;
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 | bibcode=2002RvMP...74...47A&lt;br /&gt;
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2002RvMP... 74... 47A&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|arxiv = cond-mat/0106096 }}&amp;lt;/ref&amp;gt;&lt;br /&gt;
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* (a) Scale-free networks assume a continuous growth of the number of nodes ''N'', compared to random networks which assume a fixed number of nodes. In scale-free networks the degree of the largest hub rises polynomially with the size of the network. Therefore, the degree of a hub can be high in a scale-free network. In random networks the degree of the largest node rises logaritmically (or slower) with N, thus the hub number will be small even in a very large network.&lt;br /&gt;
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无标度网络假设节点数“N”持续增长，而随机网络假设节点数为固定数目。在无标度网络中，最大枢纽节点的度数随着网络的大小而多项式地上升。因此，在无标度网络中，枢纽节点的度数可以很高。在随机网络中，最大节点的度数随着N的增大而呈线性增大(或变慢)，因此即使在一个非常大的随机网络中，枢纽节点的数量也会很小。&lt;br /&gt;
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* (b) A new node in a scale-free network has a tendency to link to a node with a higher degree, compared to a new node in a random network which links itself to a random node. This process is called [[preferential attachment]]. The tendency of a new node to link to a node with a high degree ''k'' is characterized by [[Power law|power-law distribution]] (also known as rich-gets-richer process). This idea was introduced by [[Vilfredo Pareto]] and it explained why a small percentage of the population earns most of the money. This process is present in networks as well, for example 80 percent of web links point to 15 percent of webpages. The emergence of scale-free networks is not typical only of networks created by human action, but also of such networks as metabolic networks or illness networks.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 8.[http://barabasi.com/networksciencebook/content/book_chapter_2.pdf]&amp;lt;/ref&amp;gt; This phenomenon may be explained by the example of hubs on the World Wide Web such as Facebook or Google. These webpages are very well known and therefore the tendency of other webpages pointing to them is much higher than linking to random small webpages.&lt;br /&gt;
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无标度网络中的新节点，与随机网络中的新节点相比，更倾向于连接到具有更高度的节点。这个过程称为优先依附。新节点连接到高度值''k''节点的趋势可被看做幂律分布(也被称作，越富有就越富有的过程)。这个想法是由Vilfredo Pareto提出的，它解释了为什么一小部分人赚了大部分的钱。这个过程也存在于网络中，例如80%的网络链接指向15%的网页。无标度网络的不仅是符合的人类活动网络，也可以拟合包括代谢网络或疾病网络。这种现象可以用像Facebook或谷歌这样的万维网中心的例子来解释。这些网页是非常有名的，因此其他网页指向他们的倾向比指向到随机的小网页要高得多。&lt;br /&gt;
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The mathematical explanation for [[Barabási–Albert model]]:&lt;br /&gt;
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The mathematical explanation for Barabási–Albert model:&lt;br /&gt;
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Barabási-Albert 模型的数学解释:&lt;br /&gt;
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[[File:Barabasi Albert model.gif|thumb|300px|&lt;br /&gt;
图4：The steps of the growth of the network according to the Barabasi–Albert model (&amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt;) &lt;br /&gt;
根据 Barabasi-Albert 模型 &amp;lt;math&amp;gt;m_0=m=2&amp;lt;/math&amp;gt; 分析了网络生长的步骤]]&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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The network begins with an initial connected network of &amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt; nodes.&lt;br /&gt;
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这个网络从一个初始的由&amp;lt;math&amp;gt;m_0&amp;lt;/math&amp;gt;个节点构成的连接网络开始。&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&amp;lt;ref name=&amp;quot;RMP&amp;quot;/&amp;gt;&lt;br /&gt;
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New nodes are added to the network one at a time. Each new node is connected to &amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt; existing nodes with a probability that is proportional to the number of links that the existing nodes already have. Formally, the probability &amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt; that the new node is connected to node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is&lt;br /&gt;
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每次向网络添加一个新节点。每个新的节点都被连接到&amp;lt;math&amp;gt;m \le m_0&amp;lt;/math&amp;gt;现有的节点，其概率与现有节点已经拥有的链接数量成正比。形式上，新节点与节点&amp;lt;math&amp;gt;p_i&amp;lt;/math&amp;gt;相连的概率是&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;p_i = \frac{k_i}{\sum_j k_j},&amp;lt;/math&amp;gt;&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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where &amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt; is the degree of the node &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; and the sum is taken over all pre-existing nodes &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt; (i.e. the denominator results in twice the current number of edges in the network).&lt;br /&gt;
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其中&amp;lt;math&amp;gt;k_i&amp;lt;/math&amp;gt;是节点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的度数，这个和取自所有预先存在的节点&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;。（分母的结果是当前网络中边的两倍）。&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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Emergence of hubs in networks is also related to time. In scale-free networks, nodes which emerged earlier have a higher chance of becoming a hub than latecomers. This phenomenon is called first-mover advantage and it explains why some nodes become hubs and some do not. However, in a real network, the time of emergence is not the only factor that influences the size of the hub. For example, Facebook emerged 8 years later after Google became the largest hub on the World Wide Web and yet in 2011 Facebook became the largest hub of WWW. Therefore, in real networks the growth and the size of a hub depends also on various attributes such as popularity, quality or the aging of a node.&lt;br /&gt;
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网络中枢纽节点的涌现也与时间有关。在无标度网络中，较早出现的节点比后来者更有可能成为枢纽。这种现象被称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;先发优势 First-Mover Advantage&amp;lt;/font&amp;gt;'''，它解释了为什么一些节点成为枢纽，而一些没有。然而，在一个真实的网络中，出现的时间并不是影响枢纽规模的唯一因素。例如，在谷歌成为全球最大的互联网中心8年后，Facebook 出现了，然而在2011年，Facebook 成为了全球最大的互联网中心。因此，在实际网络中，枢纽的增长和规模也取决于各种属性，如节点的流行程度、质量或老化程度。&lt;br /&gt;
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== Attributes 属性==&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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There are several attributes of Hubs in a Scale-Free Network&lt;br /&gt;
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无标度网络中的枢纽节点有几个属性&lt;br /&gt;
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=== Shortening the path lengths in a network 缩短网络中的路径距离===&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes.&amp;lt;ref&amp;gt;Barabási, Albert-László. ''Network Science: The Scale-Free Property''., p. 23.[http://barabasi.com/networksciencebook/content/book_chapter_4.pdf]&amp;lt;/ref&amp;gt; Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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The more observable hubs are in a network, the more they shrink distances between nodes. In a scale-free network, hubs serve as bridges between the small degree nodes. Since the distance of two random nodes in a scale-free network is small, we refer to scale-free networks as &amp;quot;small&amp;quot; or &amp;quot;ultra small&amp;quot;. While the difference between path distance in a very small network may not be noticeable, the difference in the path distance between a large random network and a scale-free network is remarkable.&lt;br /&gt;
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网络中可观察到的枢纽节点越多，节点之间的距离就越小。在无标度网络中，枢纽是连接度小的节点的桥梁。由于无标度网络中随机节点间的距离很小，我们称无标度网络为“小”或“超小”网络。虽然在一个非常小的网络中，路径距离的差异可能并不明显，但是在大型随机网络和无标度网络中，路径距离的差异是显著的。&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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Average path length in scale-free networks:&lt;br /&gt;
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无标度网络中的平均路径长度:&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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&amp;lt;math&amp;gt;\ell\sim\frac{\ln N}{\ln \ln N}.&amp;lt;/math&amp;gt;&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;枢纽节点的老化 Aging of hubs (nodes)&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks.&amp;lt;ref&amp;gt;[http://barabasi.com/networksciencebook/content/book_chapter_6.pdf Barabási, Albert-László. ''Network Science: Evolving Networks''., p. 3]&amp;lt;/ref&amp;gt; The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).{{Citation needed|date=May 2016}}&lt;br /&gt;
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The phenomenon present in real networks, when older hubs are shadowed in a network. This phenomenon is responsible for changes in evolution and topology of networks. The example of aging phenomenon may be the case of Facebook overtaking the position of the largest hub on the Web, Google(which was the largest node since 2000).&lt;br /&gt;
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这种现象在真实网络中有所出现，当旧的枢纽被隐藏在网络中时。这种现象导致了网络演化和拓扑结构的变化。老化现象的例子可参照 Facebook 超越了网络中最大的中心 Google (自2000年以来最大的节点)。&lt;br /&gt;
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=== '''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;鲁棒性和攻击容忍度 Robustness and Attack Tolerance&amp;lt;/font&amp;gt;''' ===&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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During the random failure of nodes or targeted attack hubs are key components of the network. During the random failure of nodes in network hubs are responsible for exceptional robustness of network.&amp;lt;ref&amp;gt;{{cite journal|title=Resilience of the Internet to Random Breakdowns|&lt;br /&gt;
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随机故障的节点或定向攻击网络关键组成部分的枢纽。在网络枢纽节点的随机失效过程中，网络的鲁棒性是由节点的随机失效决定的。&amp;lt; ref &amp;gt; { cite journal | title = Resilience of the Internet to Random breaks | &lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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journal=Phys. Rev. Lett.|&lt;br /&gt;
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日记 = 体育。牧师。李特 | &lt;br /&gt;
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year=2000|&lt;br /&gt;
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year=2000|&lt;br /&gt;
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2000年&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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first=Reoven|&lt;br /&gt;
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1 = Reoven | &lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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last=Cohen|&lt;br /&gt;
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最后 = Cohen | &lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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first2=K. |last2=Erez |first3=D. |last3=ben-Avraham |first4=S.|last4=Havlin|authorlink4=Shlomo Havlin|&lt;br /&gt;
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首先2 = k。2 = Erez | first3 = d.3 = ben-Avraham | first4 = s | last4 = Havlin | authorlink4 = Shlomo Havlin | &lt;br /&gt;
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volume=85|&lt;br /&gt;
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volume=85|&lt;br /&gt;
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85 | &lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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pages=4626–8|&lt;br /&gt;
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页数 = 4626-8&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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doi= 10.1103/PhysRevLett.85.4626|&lt;br /&gt;
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Doi = 10.1103/physrvlett. 85.4626 | &lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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url=http://link.aps.org/doi/10.1103/PhysRevLett.85.4626&lt;br /&gt;
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Http://link.aps.org/doi/10.1103/physrevlett.85.4626&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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|bibcode=2000PhRvL..85.4626C|arxiv = cond-mat/0007048 |pmid=11082612}}&lt;br /&gt;
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| bibcode = 2000PhRvL. . 85.4626 c | arxiv = cond-mat/0007048 | pmid = 11082612}&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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&amp;lt;/ref&amp;gt; The chance that a random failure would delete the hub is very small, because hubs coexists with a large number of small degree nodes. The removal of small degree nodes does not have a large effect on integrity of network. Even though the random removal would hit the hub, the chance of fragmantation of network is very small because the remaining hubs would hold the network together. In this case, hubs are the strength of a scale-free networks.&lt;br /&gt;
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由于枢纽与大量小度节点共存，随机故障删除它的几率很小。而去除小节点对网络的完整性影响不大。即使随机删除会作用到上枢纽，'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;网络碎片化 Fragmantation of Network&amp;lt;/font&amp;gt;'''的可能性也非常小，因为剩余的枢纽仍能将网络连接在一起。在这种情况下，枢纽就是无标度网络的中坚力量。&lt;br /&gt;
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During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system.&amp;lt;ref&amp;gt;{{Cite journal|author1=S. V. Buldyrev |author2=R. Parshani |author3=G. Paul |author4=H. E. Stanley |author5=S. Havlin |title = Catastrophic cascade of failures in interdependent networks|journal = Nature |volume = 464 |pages = 1025–28 |year = 2010 | doi=10.1038/nature08932 |issue=7291|url=http://havlin.biu.ac.il/Publications.php?keyword=Catastrophic+cascade+of+failures+in+interdependent+networks&amp;amp;year=*&amp;amp;match=all |pmid=20393559|arxiv=1012.0206 |bibcode=2010Natur.464.1025B }}&amp;lt;/ref&amp;gt; On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
&lt;br /&gt;
During a targeted attack on hubs, the integrity of a network will fall apart relatively fast. Since small nodes are predominantly linked to hubs, the targeted attack on the largest hubs results in destroys the network in a short period of time. The financial market meltdown in 2008 is an example of such a network failure, when bankruptcy of the largest players (hubs) led to a continuous breakdown of the whole system. On the other hand, it may have a positive effect when removing hubs in a terrorist network; targeted node deletion may destroy the whole terrorist group. The attack tolerance of a network may be increased by connecting its peripheral nodes, however it requires to double the number of links.&lt;br /&gt;
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在对枢纽进行有针对性的攻击时，网络的完整性会相对较快地崩溃。由于小节点主要连接到枢纽节点，对最大枢纽的攻击会在短时间内破坏网络。2008年的金融市场崩溃就是这种网络失灵的一个例子，当时最大的参与者(枢纽)的破产导致了整个系统的持续崩溃。另一方面，去除恐怖主义网络中的枢纽节点可能会产生积极的影响，目标节点的消失可能会摧毁整个恐怖组织。网络的攻击容忍度可以通过连接其外围节点来提高，但是它需要加倍的链接数量。&lt;br /&gt;
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=== Degree correlation 度相关===&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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The perfect degree correlation means that each degree-k node is connected only to the same degree-k nodes. Such connectivity of nodes decide the topology of networks, which has an effect on robustness of network, the attribute discussed above. If the number of links between the hubs is the same as would be expected by chance, we refer to this network as Neutral Network. If hubs tend to connected to each other while avoiding linking to small-degree nodes we refer to this network as Assortative Network. This network is relatively resistant against attacks, because hubs form a core group, which is more reduntant against hub removal. If hubs avoid connecting to each other while linking to small-degree nodes, we refer to this network as Disassortative Network. This network has a hub-and-spoke character. Therefore, if we remove the hub in this type of network, it may damage or destroy the whole network.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;完全度相关 Perfect Degree Correlation&amp;lt;/font&amp;gt;'''意味着每个度值为k的节点只连接到相同度值的节点。节点之间的这种连通性决定了网络的拓扑结构，从而影响了网络的鲁棒性。如果枢纽节点之间的链接数量与偶然预期的相同，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中性网络 Neutral Network&amp;lt;/font&amp;gt;'''。如果枢纽节点倾向于相互连接，同时避免链接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;选型网络 Assortative Network&amp;lt;/font&amp;gt;'''。这个网络抵抗攻击的能力相对较强，因为枢纽节点形成了一个核心组，这对枢纽节点的移除来说是更加冗余的。如果枢纽节点避免相互连接，同时连接到小度的节点，我们将这个网络称为'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;非选型网络 Disassortative Network&amp;lt;/font&amp;gt;'''。这个网络具有'''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;中心辐射特征 Hub-and-Spoke Character&amp;lt;/font&amp;gt;'''。因此，如果我们删除这种类型网络中的枢纽节点，可能会破坏或摧毁整个网络。&lt;br /&gt;
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==='''&amp;lt;font color=&amp;quot;#ff8000&amp;quot;&amp;gt;传播效应 Spreading phenomenon&amp;lt;/font&amp;gt;'''  ===&lt;br /&gt;
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The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction &amp;lt;ref&amp;gt;{{Cite journal|first1=Duygu |last1=Balcan |first2=Hao |last2=Hu |first3=Bruno |last3=Goncalves |first4=Paolo |last4=Bajardi |first5=Chiara |last5=Poletto |first6=Jose J.|last6=Ramasco|first7=Daniela|last7=Paolotti|first8=Nicola|last8=Perra |first9=Michele |last9=Tizzoni |first10=Wouter |last10=Van den Broeck|first11=Vittoria |last11=Colizza|first12=Alessandro |last12=Vespignani|date=14 September 2009|title=Seasonal transmission potential and activity peaks of the new influenza A(H1N1): a Monte Carlo likelihood analysis based on human mobility|journal=BMC Medicine |volume=7 |issue=45 |page=29 |doi=10.1186/1741-7015-7-45 |id= |pmid=19744314 |pmc=2755471 |arxiv=0909.2417}}&amp;lt;/ref&amp;gt; may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
&lt;br /&gt;
The hubs are also responsible for effective spreading of material on network. In an analysis of disease spreading or information flow, hubs are referred to as super-spreaders. Super-spreaders may have a positive impact, such as effective information flow, but also devastating in a case of epidemic spreading such as H1N1 or AIDS. The mathematical models such as model of H1H1 Epidemic prediction  may allow us to predict the spread of diseases based on human mobility networks, infectiousness, or social interactions among humans. Hubs are also important in the eradication of disease. In a scale-free network hubs are most likely to be infected, because of the large number of connections they have. After the hub is infected, it broadcasts the disease to the nodes it is linked to. Therefore, the selective immunization of hubs may be the cost-effective strategy in eradication of spreading disease.&lt;br /&gt;
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这些枢纽节点还负责有效地在网络上传播材料。在疾病传播或信息流的分析中，枢纽被称为超级传播者。超级传播者可能会产生积极的影响，如有效的信息流动，但在 H1N1或艾滋病等流行病传播的情况下也会产生毁灭性的影响。数学模型，如 H1H1流行病预测模型，基于人类流动网络，传染性，或人与人之间的社会互动，可以让我们预测疾病的传播。在根除疾病方面，枢纽也很重要。在无标度网络中，枢纽是最有可能被感染的，因为他们有大量的连接。在枢纽被感染后，它将疾病广播到它所链接的节点。因此，选择性免疫那些枢纽节点可能是消灭传播性疾病的成本效益策略。&lt;br /&gt;
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== References ==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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[[Category:Network theory]]&lt;br /&gt;
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Category:Network theory&lt;br /&gt;
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范畴: 网络理论&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Hub (network science)]]. Its edit history can be viewed at [[枢纽节点/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E4%B8%89%E5%85%83%E9%97%AD%E5%8C%85&amp;diff=16566</id>
		<title>三元闭包</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E4%B8%89%E5%85%83%E9%97%AD%E5%8C%85&amp;diff=16566"/>
		<updated>2020-10-22T12:20:48Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* 强三元闭包性质和局部桥 Local Bridges  */&lt;/p&gt;
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&lt;div&gt;本词条由信白初步翻译，已由Alienxj审校&lt;br /&gt;
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'''Triadic closure''' is a concept in [[social network]] theory, first suggested by [[Germany|German]] [[sociology|sociologist]] [[Georg Simmel]] in his 1908 book ''Soziologie'' [''Sociology: Investigations on the Forms of Sociation''].&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C.&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Triadic closure is a concept in social network theory, first suggested by German sociologist Georg Simmel in his 1908 book Soziologie [Sociology: Investigations on the Forms of Sociation]. Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C. This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包 Triadic Closure &amp;lt;/font&amp;gt;'''是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;社会网络 Social Network&amp;lt;/font&amp;gt;'''理论中的一个概念，最早由德国社会学家格奥尔格·西梅尔 Georg Simmel在其1908年的著作《社会学：社会形式的调查》 Sociology: Investigations on the Forms of Sociation中提出。&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt;三元闭包指的是由A，B，C三个'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点 Node&amp;lt;/font&amp;gt;'''所组成的三元组的一种性质，即如果A-B和A-C之间存在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强联系 Strong Tie &amp;lt;/font&amp;gt;'''，则B-C之间也仅存在强联系。&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; 这一性质过于极端，以至于它难以在规模较大、结构复杂的网络中被满足，然而在理解网络与网络预测等方面，它却是一种十分有用的对现实的简化。&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==History==&lt;br /&gt;
Triadic closure was made popular by [[Mark Granovetter]] in his 1973 article ''The Strength of Weak Ties''.&amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; There he synthesized the theory of [[cognitive balance]] first introduced by [[Fritz Heider]] in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
&lt;br /&gt;
Triadic closure was made popular by Mark Granovetter in his 1973 article The Strength of Weak Ties. There he synthesized the theory of cognitive balance first introduced by Fritz Heider in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
&lt;br /&gt;
==历史==&lt;br /&gt;
马克·格兰诺维特 Mark Granovetter在1973年发表的《弱链接的力量》 The Strength of Weak Ties一文使得三元闭包性质变得流行。 &amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; 在这一文章中，他综合了弗里茨·海德 Fritz Heider于1946年提出的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;认知平衡 Cognitive Balance &amp;lt;/font&amp;gt;'''理论以及Georg Simmel对社会网络的理解。 一般而言，认知平衡是指两个个体对同一事物具有产生相同感觉的倾向。 如果三个个体所组成的三元组没有闭合，那么与同一个体联系的其余两个个体均将想要闭合这一三元组，进而在关系网络中形成闭包。&lt;br /&gt;
&lt;br /&gt;
==Measurements==&lt;br /&gt;
{{Unreferenced section|date=September 2009}}&lt;br /&gt;
The two most common measures of triadic closure for a graph are (in no particular order) the [[clustering coefficient]] and transitivity for that graph.&lt;br /&gt;
&lt;br /&gt;
The two most common measures of triadic closure for a graph are (in no particular order) the clustering coefficient and transitivity for that graph.&lt;br /&gt;
&lt;br /&gt;
==测量==&lt;br /&gt;
最常见的测量一张'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;图 Graph&amp;lt;/font&amp;gt;'''的三元闭包性质的两种方法（排名不分先后）是采用该图的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;聚集系数 Clustering Coefficient &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;传递性 Transitivity&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Clustering coefficient==&lt;br /&gt;
==聚集系数==&lt;br /&gt;
&lt;br /&gt;
One measure for the presence of triadic closure is [[clustering coefficient]], as follows:&lt;br /&gt;
&lt;br /&gt;
One measure for the presence of triadic closure is clustering coefficient, as follows:&lt;br /&gt;
&lt;br /&gt;
测量三元闭包是否出现的方法之一是聚集系数，如下所示：&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the [[degree (graph theory)|degree]] of vertex i.&lt;br /&gt;
&lt;br /&gt;
Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the degree of vertex i.&lt;br /&gt;
&lt;br /&gt;
令&amp;lt;math&amp;gt;G =(V，E)&amp;lt;/math&amp;gt;是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;无向简单图 Undirected Simple Graph&amp;lt;/font&amp;gt;'''（即，没有'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;自环 Self-loops&amp;lt;/font&amp;gt;'''或'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;多重边 Multiple Edges&amp;lt;/font&amp;gt;'''的图），其中&amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点 Vertice&amp;lt;/font&amp;gt;'''集，&amp;lt;math&amp;gt;E&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;边 Edge&amp;lt;/font&amp;gt;'''集。 另外，令&amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt;分别表示图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中顶点和边的数量，并令&amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; 表示顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;度 Degree&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
&lt;br /&gt;
We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
&lt;br /&gt;
我们可以通过边集&amp;lt;math&amp;gt;((i,j),(j,k),(i,k))&amp;lt;/math&amp;gt;，将由顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;,&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt;组成的三元组定义为一个三角形。&lt;br /&gt;
&lt;br /&gt;
We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
我们也可以将顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量定义为&amp;lt;math&amp;gt;\delta(i)&amp;lt;/math&amp;gt;，并且由于每个三角形都被计数了三次，我们可以将图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中三角形的个数表达为&amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
&lt;br /&gt;
Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
假设三元闭包性质成立，则一个三元组仅需要两条强联系便可形成三角形。 因此，在三元闭包性质成立的前提下，顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的理论三角形的数量为&amp;lt;math&amp;gt;\tau(i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;，假设&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;。我们可以表示&amp;lt;math&amp;gt;\tau(G) = \frac{1}{3} \sum_{i\in V} \ \tau(i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
&lt;br /&gt;
Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the [[clustering coefficient]] &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the [[clustering coefficient]] &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
&lt;br /&gt;
Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the clustering coefficient &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the clustering coefficient &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
&lt;br /&gt;
现在，对于具有&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;的顶点，顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的聚集系数是其拥有的三角形的占比，即&amp;lt;math&amp;gt;\frac{\delta(i)}{\tau(i)}&amp;lt;/math&amp;gt;。 因此，图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;的聚集系数&amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt;由&amp;lt;math&amp;gt; C(G)=\frac {1}{N_2} \sum_{i \in V,d_i \ge 2}c(i)&amp;lt;/math&amp;gt;给出，其中&amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt;是度至少为2的顶点数量。&lt;br /&gt;
&lt;br /&gt;
==Transitivity==&lt;br /&gt;
==传递性==&lt;br /&gt;
&lt;br /&gt;
Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
测量三元闭包是否出现的另一方法是传递性，定义为&amp;lt;math&amp;gt;T(G)= \frac{3\delta(G)}{\tau(G)}&amp;lt;/math&amp;gt;。&lt;br /&gt;
&lt;br /&gt;
==Causes and effects==&lt;br /&gt;
==形成及其影响==&lt;br /&gt;
&lt;br /&gt;
In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&lt;br /&gt;
&lt;br /&gt;
在一个信任网络中，三元闭包性质的出现往往是由于传递性。如果节点A信任节点B，并且节点B信任节点C，则节点A将具有信任节点C的基础。在社会网络中，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强三元闭包 Strong Triadic Closure&amp;lt;/font&amp;gt;'''性质的出现往往是由于节点A与节点C拥有共同邻居节点B，在此情况下，节点A与节点C相遇的机会将会增加，进而至少产生一条'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;弱联系 Weak Tie&amp;lt;/font&amp;gt;'''。此外，由于两段分离的关系所带来的潜在压力，节点B也具有将节点A和节点C聚在一起的动机。&lt;br /&gt;
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Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
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Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
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遵循此原理的网络将高度互连且具有极高的聚集系数。 与此相反，不遵循该原理的网络的连通性则较差，且一旦包含负面关系，网络则可能会变得较不稳定。&lt;br /&gt;
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Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&lt;br /&gt;
&lt;br /&gt;
三元闭包是分析网络如何随时间演变的一个良好模型。 '''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;简单图论 Simple Graph Theory&amp;lt;/font&amp;gt;'''倾向于在某个时点分析网络，而应用三元闭包原理则可以预测网络中联系的形成，以及网络连通性的发展。&lt;br /&gt;
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In [[social networks]], triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
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In social networks, triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
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在社会网络中，三元闭包将促进合作行为，但是在新联系是通过现存联系而产生的情况下，平均而言个体所拥有的合作伙伴相对数量将小于个体在总体中随机选择合作伙伴时所拥有的合作伙伴相对数量。这一现象的产生可以从结构与信息两个角度进行解释。基于结构角度而言，网络具有高度聚集性的倾向。基于信息角度而言，我们通常假设，相较于随机的陌生人，个体对朋友的朋友有所了解。&lt;br /&gt;
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==Strong Triadic Closure Property and local bridges==&lt;br /&gt;
==强三元闭包性质和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;局部桥 Local Bridges &amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A [[local bridge]] occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
&lt;br /&gt;
Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A local bridge occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
&lt;br /&gt;
强三元闭包性质指，如果一个节点与两个邻居具有强联系，则这些邻居之间必须至少有一条弱联系。另一方面，当某节点在两个互不相连的邻居间充当'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;中间人 Gatekeeper&amp;lt;/font&amp;gt;'''时，则将产生局部桥。在遵循强三元闭包性质的网络中，局部桥涉及的节点之间的联系必然至少包括一条弱联系。&lt;br /&gt;
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==Proof by contradiction==&lt;br /&gt;
==反证法==&lt;br /&gt;
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Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&lt;br /&gt;
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假设节点B是节点A和C之间的局部桥，则所涉及的节点之间没有弱联系。 如果B与A和C之间均具有强联系，则根据强三元闭包性质的定义，节点A和C之间将形成弱联系。但是，这与B是局部桥的事实相矛盾。 因此，局部桥涉及的至少一个节点需要是弱联系，以防止三元闭包的产生。&lt;br /&gt;
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==References==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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{{Social networking}}&lt;br /&gt;
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{{DEFAULTSORT:Triadic Closure}}&lt;br /&gt;
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[[Category:Social systems]]&lt;br /&gt;
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Category:Social systems&lt;br /&gt;
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类别: 社会系统&lt;br /&gt;
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[[Category:Sociological terminology]]&lt;br /&gt;
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类别: 社会学术语&lt;br /&gt;
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		<author><name>Alienxj</name></author>
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		<title>三元闭包</title>
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		<summary type="html">&lt;p&gt;Alienxj：/* 强三元闭包性和局部桥 Local Bridges  */&lt;/p&gt;
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&lt;div&gt;本词条由信白初步翻译，已由Alienxj审校&lt;br /&gt;
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'''Triadic closure''' is a concept in [[social network]] theory, first suggested by [[Germany|German]] [[sociology|sociologist]] [[Georg Simmel]] in his 1908 book ''Soziologie'' [''Sociology: Investigations on the Forms of Sociation''].&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C.&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Triadic closure is a concept in social network theory, first suggested by German sociologist Georg Simmel in his 1908 book Soziologie [Sociology: Investigations on the Forms of Sociation]. Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C. This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包 Triadic Closure &amp;lt;/font&amp;gt;'''是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;社会网络 Social Network&amp;lt;/font&amp;gt;'''理论中的一个概念，最早由德国社会学家格奥尔格·西梅尔 Georg Simmel在其1908年的著作《社会学：社会形式的调查》 Sociology: Investigations on the Forms of Sociation中提出。&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt;三元闭包指的是由A，B，C三个'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点 Node&amp;lt;/font&amp;gt;'''所组成的三元组的一种性质，即如果A-B和A-C之间存在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强联系 Strong Tie &amp;lt;/font&amp;gt;'''，则B-C之间也仅存在强联系。&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; 这一性质过于极端，以至于它难以在规模较大、结构复杂的网络中被满足，然而在理解网络与网络预测等方面，它却是一种十分有用的对现实的简化。&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==History==&lt;br /&gt;
Triadic closure was made popular by [[Mark Granovetter]] in his 1973 article ''The Strength of Weak Ties''.&amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; There he synthesized the theory of [[cognitive balance]] first introduced by [[Fritz Heider]] in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
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Triadic closure was made popular by Mark Granovetter in his 1973 article The Strength of Weak Ties. There he synthesized the theory of cognitive balance first introduced by Fritz Heider in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
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==历史==&lt;br /&gt;
马克·格兰诺维特 Mark Granovetter在1973年发表的《弱链接的力量》 The Strength of Weak Ties一文使得三元闭包性质变得流行。 &amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; 在这一文章中，他综合了弗里茨·海德 Fritz Heider于1946年提出的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;认知平衡 Cognitive Balance &amp;lt;/font&amp;gt;'''理论以及Georg Simmel对社会网络的理解。 一般而言，认知平衡是指两个个体对同一事物具有产生相同感觉的倾向。 如果三个个体所组成的三元组没有闭合，那么与同一个体联系的其余两个个体均将想要闭合这一三元组，进而在关系网络中形成闭包。&lt;br /&gt;
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==Measurements==&lt;br /&gt;
{{Unreferenced section|date=September 2009}}&lt;br /&gt;
The two most common measures of triadic closure for a graph are (in no particular order) the [[clustering coefficient]] and transitivity for that graph.&lt;br /&gt;
&lt;br /&gt;
The two most common measures of triadic closure for a graph are (in no particular order) the clustering coefficient and transitivity for that graph.&lt;br /&gt;
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==测量==&lt;br /&gt;
最常见的测量一张'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;图 Graph&amp;lt;/font&amp;gt;'''的三元闭包性质的两种方法（排名不分先后）是采用该图的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;聚集系数 Clustering Coefficient &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;传递性 Transitivity&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Clustering coefficient==&lt;br /&gt;
==聚集系数==&lt;br /&gt;
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One measure for the presence of triadic closure is [[clustering coefficient]], as follows:&lt;br /&gt;
&lt;br /&gt;
One measure for the presence of triadic closure is clustering coefficient, as follows:&lt;br /&gt;
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测量三元闭包是否出现的方法之一是聚集系数，如下所示：&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the [[degree (graph theory)|degree]] of vertex i.&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the degree of vertex i.&lt;br /&gt;
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令&amp;lt;math&amp;gt;G =(V，E)&amp;lt;/math&amp;gt;是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;无向简单图 Undirected Simple Graph&amp;lt;/font&amp;gt;'''（即，没有'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;自环 Self-loops&amp;lt;/font&amp;gt;'''或'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;多重边 Multiple Edges&amp;lt;/font&amp;gt;'''的图），其中&amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点 Vertice&amp;lt;/font&amp;gt;'''集，&amp;lt;math&amp;gt;E&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;边 Edge&amp;lt;/font&amp;gt;'''集。 另外，令&amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt;分别表示图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中顶点和边的数量，并令&amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; 表示顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;度 Degree&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
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我们可以通过边集&amp;lt;math&amp;gt;((i,j),(j,k),(i,k))&amp;lt;/math&amp;gt;，将由顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;,&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt;组成的三元组定义为一个三角形。&lt;br /&gt;
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We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
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We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
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我们也可以将顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量定义为&amp;lt;math&amp;gt;\delta(i)&amp;lt;/math&amp;gt;，并且由于每个三角形都被计数了三次，我们可以将图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中三角形的个数表达为&amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
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Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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假设三元闭包性质成立，则一个三元组仅需要两条强联系便可形成三角形。 因此，在三元闭包性质成立的前提下，顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的理论三角形的数量为&amp;lt;math&amp;gt;\tau(i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;，假设&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;。我们可以表示&amp;lt;math&amp;gt;\tau(G) = \frac{1}{3} \sum_{i\in V} \ \tau(i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
&lt;br /&gt;
Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the [[clustering coefficient]] &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the [[clustering coefficient]] &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
&lt;br /&gt;
Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the clustering coefficient &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the clustering coefficient &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
&lt;br /&gt;
现在，对于具有&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;的顶点，顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的聚集系数是其拥有的三角形的占比，即&amp;lt;math&amp;gt;\frac{\delta(i)}{\tau(i)}&amp;lt;/math&amp;gt;。 因此，图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;的聚集系数&amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt;由&amp;lt;math&amp;gt; C(G)=\frac {1}{N_2} \sum_{i \in V,d_i \ge 2}c(i)&amp;lt;/math&amp;gt;给出，其中&amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt;是度至少为2的顶点数量。&lt;br /&gt;
&lt;br /&gt;
==Transitivity==&lt;br /&gt;
==传递性==&lt;br /&gt;
&lt;br /&gt;
Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
测量三元闭包是否出现的另一方法是传递性，定义为&amp;lt;math&amp;gt;T(G)= \frac{3\delta(G)}{\tau(G)}&amp;lt;/math&amp;gt;。&lt;br /&gt;
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==Causes and effects==&lt;br /&gt;
==形成及其影响==&lt;br /&gt;
&lt;br /&gt;
In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&lt;br /&gt;
&lt;br /&gt;
在一个信任网络中，三元闭包性质的出现往往是由于传递性。如果节点A信任节点B，并且节点B信任节点C，则节点A将具有信任节点C的基础。在社会网络中，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强三元闭包 Strong Triadic Closure&amp;lt;/font&amp;gt;'''性质的出现往往是由于节点A与节点C拥有共同邻居节点B，在此情况下，节点A与节点C相遇的机会将会增加，进而至少产生一条'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;弱联系 Weak Tie&amp;lt;/font&amp;gt;'''。此外，由于两段分离的关系所带来的潜在压力，节点B也具有将节点A和节点C聚在一起的动机。&lt;br /&gt;
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&lt;br /&gt;
Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
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Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
&lt;br /&gt;
遵循此原理的网络将高度互连且具有极高的聚集系数。 与此相反，不遵循该原理的网络的连通性则较差，且一旦包含负面关系，网络则可能会变得较不稳定。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&lt;br /&gt;
&lt;br /&gt;
三元闭包是分析网络如何随时间演变的一个良好模型。 '''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;简单图论 Simple Graph Theory&amp;lt;/font&amp;gt;'''倾向于在某个时点分析网络，而应用三元闭包原理则可以预测网络中联系的形成，以及网络连通性的发展。&lt;br /&gt;
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In [[social networks]], triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
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In social networks, triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
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在社会网络中，三元闭包将促进合作行为，但是在新联系是通过现存联系而产生的情况下，平均而言个体所拥有的合作伙伴相对数量将小于个体在总体中随机选择合作伙伴时所拥有的合作伙伴相对数量。这一现象的产生可以从结构与信息两个角度进行解释。基于结构角度而言，网络具有高度聚集性的倾向。基于信息角度而言，我们通常假设，相较于随机的陌生人，个体对朋友的朋友有所了解。&lt;br /&gt;
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==Strong Triadic Closure Property and local bridges==&lt;br /&gt;
==强三元闭包性质和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;局部桥 Local Bridges &amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A [[local bridge]] occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
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Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A local bridge occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
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强三元闭包性指，如果一个节点与两个邻居具有强联系，则这些邻居之间必须至少有一条弱联系。另一方面，当某节点在两个互不相连的邻居间充当'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;中间人 Gatekeeper&amp;lt;/font&amp;gt;'''时，则将产生局部桥。在遵循强三元闭包性质的网络中，局部桥涉及的节点之间的联系必然至少包括一条弱联系。&lt;br /&gt;
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==Proof by contradiction==&lt;br /&gt;
==反证法==&lt;br /&gt;
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Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&lt;br /&gt;
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假设节点B是节点A和C之间的局部桥，则所涉及的节点之间没有弱联系。 如果B与A和C之间均具有强联系，则根据强三元闭包性质的定义，节点A和C之间将形成弱联系。但是，这与B是局部桥的事实相矛盾。 因此，局部桥涉及的至少一个节点需要是弱联系，以防止三元闭包的产生。&lt;br /&gt;
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==References==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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{{Social networking}}&lt;br /&gt;
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{{DEFAULTSORT:Triadic Closure}}&lt;br /&gt;
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[[Category:Social systems]]&lt;br /&gt;
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Category:Social systems&lt;br /&gt;
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类别: 社会系统&lt;br /&gt;
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[[Category:Sociological terminology]]&lt;br /&gt;
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Category:Sociological terminology&lt;br /&gt;
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类别: 社会学术语&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Triadic closure]]. Its edit history can be viewed at [[三元闭包/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
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	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E4%B8%89%E5%85%83%E9%97%AD%E5%8C%85&amp;diff=16564</id>
		<title>三元闭包</title>
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		<updated>2020-10-22T12:17:16Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* 聚集系数 */&lt;/p&gt;
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&lt;div&gt;本词条由信白初步翻译，已由Alienxj审校&lt;br /&gt;
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'''Triadic closure''' is a concept in [[social network]] theory, first suggested by [[Germany|German]] [[sociology|sociologist]] [[Georg Simmel]] in his 1908 book ''Soziologie'' [''Sociology: Investigations on the Forms of Sociation''].&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C.&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Triadic closure is a concept in social network theory, first suggested by German sociologist Georg Simmel in his 1908 book Soziologie [Sociology: Investigations on the Forms of Sociation]. Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C. This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包 Triadic Closure &amp;lt;/font&amp;gt;'''是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;社会网络 Social Network&amp;lt;/font&amp;gt;'''理论中的一个概念，最早由德国社会学家格奥尔格·西梅尔 Georg Simmel在其1908年的著作《社会学：社会形式的调查》 Sociology: Investigations on the Forms of Sociation中提出。&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt;三元闭包指的是由A，B，C三个'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点 Node&amp;lt;/font&amp;gt;'''所组成的三元组的一种性质，即如果A-B和A-C之间存在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强联系 Strong Tie &amp;lt;/font&amp;gt;'''，则B-C之间也仅存在强联系。&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; 这一性质过于极端，以至于它难以在规模较大、结构复杂的网络中被满足，然而在理解网络与网络预测等方面，它却是一种十分有用的对现实的简化。&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==History==&lt;br /&gt;
Triadic closure was made popular by [[Mark Granovetter]] in his 1973 article ''The Strength of Weak Ties''.&amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; There he synthesized the theory of [[cognitive balance]] first introduced by [[Fritz Heider]] in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
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Triadic closure was made popular by Mark Granovetter in his 1973 article The Strength of Weak Ties. There he synthesized the theory of cognitive balance first introduced by Fritz Heider in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
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==历史==&lt;br /&gt;
马克·格兰诺维特 Mark Granovetter在1973年发表的《弱链接的力量》 The Strength of Weak Ties一文使得三元闭包性质变得流行。 &amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; 在这一文章中，他综合了弗里茨·海德 Fritz Heider于1946年提出的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;认知平衡 Cognitive Balance &amp;lt;/font&amp;gt;'''理论以及Georg Simmel对社会网络的理解。 一般而言，认知平衡是指两个个体对同一事物具有产生相同感觉的倾向。 如果三个个体所组成的三元组没有闭合，那么与同一个体联系的其余两个个体均将想要闭合这一三元组，进而在关系网络中形成闭包。&lt;br /&gt;
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==Measurements==&lt;br /&gt;
{{Unreferenced section|date=September 2009}}&lt;br /&gt;
The two most common measures of triadic closure for a graph are (in no particular order) the [[clustering coefficient]] and transitivity for that graph.&lt;br /&gt;
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The two most common measures of triadic closure for a graph are (in no particular order) the clustering coefficient and transitivity for that graph.&lt;br /&gt;
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==测量==&lt;br /&gt;
最常见的测量一张'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;图 Graph&amp;lt;/font&amp;gt;'''的三元闭包性质的两种方法（排名不分先后）是采用该图的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;聚集系数 Clustering Coefficient &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;传递性 Transitivity&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Clustering coefficient==&lt;br /&gt;
==聚集系数==&lt;br /&gt;
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One measure for the presence of triadic closure is [[clustering coefficient]], as follows:&lt;br /&gt;
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One measure for the presence of triadic closure is clustering coefficient, as follows:&lt;br /&gt;
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测量三元闭包是否出现的方法之一是聚集系数，如下所示：&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the [[degree (graph theory)|degree]] of vertex i.&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the degree of vertex i.&lt;br /&gt;
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令&amp;lt;math&amp;gt;G =(V，E)&amp;lt;/math&amp;gt;是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;无向简单图 Undirected Simple Graph&amp;lt;/font&amp;gt;'''（即，没有'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;自环 Self-loops&amp;lt;/font&amp;gt;'''或'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;多重边 Multiple Edges&amp;lt;/font&amp;gt;'''的图），其中&amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点 Vertice&amp;lt;/font&amp;gt;'''集，&amp;lt;math&amp;gt;E&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;边 Edge&amp;lt;/font&amp;gt;'''集。 另外，令&amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt;分别表示图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中顶点和边的数量，并令&amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; 表示顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;度 Degree&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
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我们可以通过边集&amp;lt;math&amp;gt;((i,j),(j,k),(i,k))&amp;lt;/math&amp;gt;，将由顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;,&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt;组成的三元组定义为一个三角形。&lt;br /&gt;
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We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
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We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
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我们也可以将顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量定义为&amp;lt;math&amp;gt;\delta(i)&amp;lt;/math&amp;gt;，并且由于每个三角形都被计数了三次，我们可以将图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中三角形的个数表达为&amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
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Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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假设三元闭包性质成立，则一个三元组仅需要两条强联系便可形成三角形。 因此，在三元闭包性质成立的前提下，顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的理论三角形的数量为&amp;lt;math&amp;gt;\tau(i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;，假设&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;。我们可以表示&amp;lt;math&amp;gt;\tau(G) = \frac{1}{3} \sum_{i\in V} \ \tau(i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
&lt;br /&gt;
Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the [[clustering coefficient]] &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the [[clustering coefficient]] &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
&lt;br /&gt;
Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the clustering coefficient &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the clustering coefficient &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
&lt;br /&gt;
现在，对于具有&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;的顶点，顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的聚集系数是其拥有的三角形的占比，即&amp;lt;math&amp;gt;\frac{\delta(i)}{\tau(i)}&amp;lt;/math&amp;gt;。 因此，图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;的聚集系数&amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt;由&amp;lt;math&amp;gt; C(G)=\frac {1}{N_2} \sum_{i \in V,d_i \ge 2}c(i)&amp;lt;/math&amp;gt;给出，其中&amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt;是度至少为2的顶点数量。&lt;br /&gt;
&lt;br /&gt;
==Transitivity==&lt;br /&gt;
==传递性==&lt;br /&gt;
&lt;br /&gt;
Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
测量三元闭包是否出现的另一方法是传递性，定义为&amp;lt;math&amp;gt;T(G)= \frac{3\delta(G)}{\tau(G)}&amp;lt;/math&amp;gt;。&lt;br /&gt;
&lt;br /&gt;
==Causes and effects==&lt;br /&gt;
==形成及其影响==&lt;br /&gt;
&lt;br /&gt;
In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&lt;br /&gt;
&lt;br /&gt;
在一个信任网络中，三元闭包性质的出现往往是由于传递性。如果节点A信任节点B，并且节点B信任节点C，则节点A将具有信任节点C的基础。在社会网络中，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强三元闭包 Strong Triadic Closure&amp;lt;/font&amp;gt;'''性质的出现往往是由于节点A与节点C拥有共同邻居节点B，在此情况下，节点A与节点C相遇的机会将会增加，进而至少产生一条'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;弱联系 Weak Tie&amp;lt;/font&amp;gt;'''。此外，由于两段分离的关系所带来的潜在压力，节点B也具有将节点A和节点C聚在一起的动机。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
&lt;br /&gt;
Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
&lt;br /&gt;
遵循此原理的网络将高度互连且具有极高的聚集系数。 与此相反，不遵循该原理的网络的连通性则较差，且一旦包含负面关系，网络则可能会变得较不稳定。&lt;br /&gt;
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Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&lt;br /&gt;
&lt;br /&gt;
三元闭包是分析网络如何随时间演变的一个良好模型。 '''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;简单图论 Simple Graph Theory&amp;lt;/font&amp;gt;'''倾向于在某个时点分析网络，而应用三元闭包原理则可以预测网络中联系的形成，以及网络连通性的发展。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
In [[social networks]], triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
&lt;br /&gt;
In social networks, triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
&lt;br /&gt;
在社会网络中，三元闭包将促进合作行为，但是在新联系是通过现存联系而产生的情况下，平均而言个体所拥有的合作伙伴相对数量将小于个体在总体中随机选择合作伙伴时所拥有的合作伙伴相对数量。这一现象的产生可以从结构与信息两个角度进行解释。基于结构角度而言，网络具有高度聚集性的倾向。基于信息角度而言，我们通常假设，相较于随机的陌生人，个体对朋友的朋友有所了解。&lt;br /&gt;
&lt;br /&gt;
==Strong Triadic Closure Property and local bridges==&lt;br /&gt;
==强三元闭包性和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;局部桥 Local Bridges &amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A [[local bridge]] occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
&lt;br /&gt;
Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A local bridge occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
&lt;br /&gt;
强三元闭包性指，如果一个节点与两个邻居具有强联系，则这些邻居之间必须至少有一条弱联系。另一方面，当某节点在两个互不相连的邻居间充当'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;中间人 Gatekeeper&amp;lt;/font&amp;gt;'''时，则将产生局部桥。在遵循强三元闭包性质的网络中，局部桥涉及的节点之间的联系必然至少包括一条弱联系。&lt;br /&gt;
&lt;br /&gt;
==Proof by contradiction==&lt;br /&gt;
==反证法==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&lt;br /&gt;
&lt;br /&gt;
假设节点B是节点A和C之间的局部桥，则所涉及的节点之间没有弱联系。 如果B与A和C之间均具有强联系，则根据强三元闭包性质的定义，节点A和C之间将形成弱联系。但是，这与B是局部桥的事实相矛盾。 因此，局部桥涉及的至少一个节点需要是弱联系，以防止三元闭包的产生。&lt;br /&gt;
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==References==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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{{Social networking}}&lt;br /&gt;
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{{DEFAULTSORT:Triadic Closure}}&lt;br /&gt;
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[[Category:Social systems]]&lt;br /&gt;
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Category:Social systems&lt;br /&gt;
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类别: 社会系统&lt;br /&gt;
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[[Category:Sociological terminology]]&lt;br /&gt;
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Category:Sociological terminology&lt;br /&gt;
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类别: 社会学术语&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Triadic closure]]. Its edit history can be viewed at [[三元闭包/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
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	<entry>
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		<title>三元闭包</title>
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		<updated>2020-10-22T12:13:44Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：&lt;/p&gt;
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&lt;div&gt;本词条由信白初步翻译，已由Alienxj审校&lt;br /&gt;
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'''Triadic closure''' is a concept in [[social network]] theory, first suggested by [[Germany|German]] [[sociology|sociologist]] [[Georg Simmel]] in his 1908 book ''Soziologie'' [''Sociology: Investigations on the Forms of Sociation''].&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C.&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Triadic closure is a concept in social network theory, first suggested by German sociologist Georg Simmel in his 1908 book Soziologie [Sociology: Investigations on the Forms of Sociation]. Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C. This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包 Triadic Closure &amp;lt;/font&amp;gt;'''是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;社会网络 Social Network&amp;lt;/font&amp;gt;'''理论中的一个概念，最早由德国社会学家格奥尔格·西梅尔 Georg Simmel在其1908年的著作《社会学：社会形式的调查》 Sociology: Investigations on the Forms of Sociation中提出。&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt;三元闭包指的是由A，B，C三个'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点 Node&amp;lt;/font&amp;gt;'''所组成的三元组的一种性质，即如果A-B和A-C之间存在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强联系 Strong Tie &amp;lt;/font&amp;gt;'''，则B-C之间也仅存在强联系。&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; 这一性质过于极端，以至于它难以在规模较大、结构复杂的网络中被满足，然而在理解网络与网络预测等方面，它却是一种十分有用的对现实的简化。&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==History==&lt;br /&gt;
Triadic closure was made popular by [[Mark Granovetter]] in his 1973 article ''The Strength of Weak Ties''.&amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; There he synthesized the theory of [[cognitive balance]] first introduced by [[Fritz Heider]] in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
&lt;br /&gt;
Triadic closure was made popular by Mark Granovetter in his 1973 article The Strength of Weak Ties. There he synthesized the theory of cognitive balance first introduced by Fritz Heider in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
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==历史==&lt;br /&gt;
马克·格兰诺维特 Mark Granovetter在1973年发表的《弱链接的力量》 The Strength of Weak Ties一文使得三元闭包性质变得流行。 &amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; 在这一文章中，他综合了弗里茨·海德 Fritz Heider于1946年提出的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;认知平衡 Cognitive Balance &amp;lt;/font&amp;gt;'''理论以及Georg Simmel对社会网络的理解。 一般而言，认知平衡是指两个个体对同一事物具有产生相同感觉的倾向。 如果三个个体所组成的三元组没有闭合，那么与同一个体联系的其余两个个体均将想要闭合这一三元组，进而在关系网络中形成闭包。&lt;br /&gt;
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==Measurements==&lt;br /&gt;
{{Unreferenced section|date=September 2009}}&lt;br /&gt;
The two most common measures of triadic closure for a graph are (in no particular order) the [[clustering coefficient]] and transitivity for that graph.&lt;br /&gt;
&lt;br /&gt;
The two most common measures of triadic closure for a graph are (in no particular order) the clustering coefficient and transitivity for that graph.&lt;br /&gt;
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==测量==&lt;br /&gt;
最常见的测量一张'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;图 Graph&amp;lt;/font&amp;gt;'''的三元闭包性质的两种方法（排名不分先后）是采用该图的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;聚集系数 Clustering Coefficient &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;传递性 Transitivity&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Clustering coefficient==&lt;br /&gt;
==聚集系数==&lt;br /&gt;
&lt;br /&gt;
One measure for the presence of triadic closure is [[clustering coefficient]], as follows:&lt;br /&gt;
&lt;br /&gt;
One measure for the presence of triadic closure is clustering coefficient, as follows:&lt;br /&gt;
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测量三元闭包是否出现的方法之一是聚集系数，如下所示：&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the [[degree (graph theory)|degree]] of vertex i.&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the degree of vertex i.&lt;br /&gt;
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令&amp;lt;math&amp;gt;G =(V，E)&amp;lt;/math&amp;gt;是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;无向简单图 Undirected Simple Graph&amp;lt;/font&amp;gt;'''（即，没有'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;自环 Self-loops&amp;lt;/font&amp;gt;'''或'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;多重边 Multiple Edges&amp;lt;/font&amp;gt;'''的图），其中&amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点 Vertice&amp;lt;/font&amp;gt;'''集，&amp;lt;math&amp;gt;E&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;边 Edge&amp;lt;/font&amp;gt;'''集。 另外，令&amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt;分别表示图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中顶点和边的数量，并令&amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; 表示顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;度 Degree&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
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我们可以通过边集&amp;lt;math&amp;gt;((i,j),(j,k),(i,k))&amp;lt;/math&amp;gt;，将由顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;,&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt;组成的三元组定义为一个三角形。&lt;br /&gt;
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We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
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We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
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我们也可以将顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量定义为&amp;lt;math&amp;gt;\delta(i)&amp;lt;/math&amp;gt;，并且由于每个三角形都被计数了三次，我们可以将图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中三角形的个数表达为&amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
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Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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假设三元闭包性质成立，则一个三元组仅需要两条强联系便可形成三角形。 因此，在三元闭包性质成立的前提下，理论上顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量为&amp;lt;math&amp;gt;\tau(i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;，假设&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;。我们可以表示&amp;lt;math&amp;gt;\tau(G) = \frac{1}{3} \sum_{i\in V} \ \tau(i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
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Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the [[clustering coefficient]] &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the [[clustering coefficient]] &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
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Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the clustering coefficient &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the clustering coefficient &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
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现在，对于具有&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;的顶点，顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的聚集系数是其拥有的三角形的占比，即&amp;lt;math&amp;gt;\frac{\delta(i)}{\tau(i)}&amp;lt;/math&amp;gt;。 因此，图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;的聚集系数&amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt;由&amp;lt;math&amp;gt; C(G)=\frac {1}{N_2} \sum_{i \in V,d_i \ge 2}c(i)&amp;lt;/math&amp;gt;给出，其中&amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt;是度至少为2的顶点数量。&lt;br /&gt;
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==Transitivity==&lt;br /&gt;
==传递性==&lt;br /&gt;
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Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
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Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
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测量三元闭包是否出现的另一方法是传递性，定义为&amp;lt;math&amp;gt;T(G)= \frac{3\delta(G)}{\tau(G)}&amp;lt;/math&amp;gt;。&lt;br /&gt;
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==Causes and effects==&lt;br /&gt;
==形成及其影响==&lt;br /&gt;
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In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
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In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&lt;br /&gt;
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在一个信任网络中，三元闭包性质的出现往往是由于传递性。如果节点A信任节点B，并且节点B信任节点C，则节点A将具有信任节点C的基础。在社会网络中，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强三元闭包 Strong Triadic Closure&amp;lt;/font&amp;gt;'''性质的出现往往是由于节点A与节点C拥有共同邻居节点B，在此情况下，节点A与节点C相遇的机会将会增加，进而至少产生一条'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;弱联系 Weak Tie&amp;lt;/font&amp;gt;'''。此外，由于两段分离的关系所带来的潜在压力，节点B也具有将节点A和节点C聚在一起的动机。&lt;br /&gt;
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Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
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Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
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遵循此原理的网络将高度互连且具有极高的聚集系数。 与此相反，不遵循该原理的网络的连通性则较差，且一旦包含负面关系，网络则可能会变得较不稳定。&lt;br /&gt;
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Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
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Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&lt;br /&gt;
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三元闭包是分析网络如何随时间演变的一个良好模型。 '''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;简单图论 Simple Graph Theory&amp;lt;/font&amp;gt;'''倾向于在某个时点分析网络，而应用三元闭包原理则可以预测网络中联系的形成，以及网络连通性的发展。&lt;br /&gt;
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In [[social networks]], triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
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In social networks, triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
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在社会网络中，三元闭包将促进合作行为，但是在新联系是通过现存联系而产生的情况下，平均而言个体所拥有的合作伙伴相对数量将小于个体在总体中随机选择合作伙伴时所拥有的合作伙伴相对数量。这一现象的产生可以从结构与信息两个角度进行解释。基于结构角度而言，网络具有高度聚集性的倾向。基于信息角度而言，我们通常假设，相较于随机的陌生人，个体对朋友的朋友有所了解。&lt;br /&gt;
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==Strong Triadic Closure Property and local bridges==&lt;br /&gt;
==强三元闭包性和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;局部桥 Local Bridges &amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A [[local bridge]] occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
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Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A local bridge occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
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强三元闭包性指，如果一个节点与两个邻居具有强联系，则这些邻居之间必须至少有一条弱联系。另一方面，当某节点在两个互不相连的邻居间充当'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;中间人 Gatekeeper&amp;lt;/font&amp;gt;'''时，则将产生局部桥。在遵循强三元闭包性质的网络中，局部桥涉及的节点之间的联系必然至少包括一条弱联系。&lt;br /&gt;
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==Proof by contradiction==&lt;br /&gt;
==反证法==&lt;br /&gt;
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&lt;br /&gt;
&lt;br /&gt;
Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&lt;br /&gt;
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假设节点B是节点A和C之间的局部桥，则所涉及的节点之间没有弱联系。 如果B与A和C之间均具有强联系，则根据强三元闭包性质的定义，节点A和C之间将形成弱联系。但是，这与B是局部桥的事实相矛盾。 因此，局部桥涉及的至少一个节点需要是弱联系，以防止三元闭包的产生。&lt;br /&gt;
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==References==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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{{Social networking}}&lt;br /&gt;
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{{DEFAULTSORT:Triadic Closure}}&lt;br /&gt;
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[[Category:Social systems]]&lt;br /&gt;
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Category:Social systems&lt;br /&gt;
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类别: 社会系统&lt;br /&gt;
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[[Category:Sociological terminology]]&lt;br /&gt;
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Category:Sociological terminology&lt;br /&gt;
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类别: 社会学术语&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Triadic closure]]. Its edit history can be viewed at [[三元闭包/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E4%B8%89%E5%85%83%E9%97%AD%E5%8C%85&amp;diff=16562</id>
		<title>三元闭包</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E4%B8%89%E5%85%83%E9%97%AD%E5%8C%85&amp;diff=16562"/>
		<updated>2020-10-22T12:11:32Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Proof by contradiction */&lt;/p&gt;
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&lt;div&gt;本词条由信白初步翻译&lt;br /&gt;
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'''Triadic closure''' is a concept in [[social network]] theory, first suggested by [[Germany|German]] [[sociology|sociologist]] [[Georg Simmel]] in his 1908 book ''Soziologie'' [''Sociology: Investigations on the Forms of Sociation''].&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C.&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Triadic closure is a concept in social network theory, first suggested by German sociologist Georg Simmel in his 1908 book Soziologie [Sociology: Investigations on the Forms of Sociation]. Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C. This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包 Triadic Closure &amp;lt;/font&amp;gt;'''是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;社会网络 Social Network&amp;lt;/font&amp;gt;'''理论中的一个概念，最早由德国社会学家格奥尔格·西梅尔 Georg Simmel在其1908年的著作《社会学：社会形式的调查》 Sociology: Investigations on the Forms of Sociation中提出。&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt;三元闭包指的是由A，B，C三个'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点 Node&amp;lt;/font&amp;gt;'''所组成的三元组的一种性质，即如果A-B和A-C之间存在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强联系 Strong Tie &amp;lt;/font&amp;gt;'''，则B-C之间也仅存在强联系。&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; 这一性质过于极端，以至于它难以在规模较大、结构复杂的网络中被满足，然而在理解网络与网络预测等方面，它却是一种十分有用的对现实的简化。&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==History==&lt;br /&gt;
Triadic closure was made popular by [[Mark Granovetter]] in his 1973 article ''The Strength of Weak Ties''.&amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; There he synthesized the theory of [[cognitive balance]] first introduced by [[Fritz Heider]] in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
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Triadic closure was made popular by Mark Granovetter in his 1973 article The Strength of Weak Ties. There he synthesized the theory of cognitive balance first introduced by Fritz Heider in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
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==历史==&lt;br /&gt;
马克·格兰诺维特 Mark Granovetter在1973年发表的《弱链接的力量》 The Strength of Weak Ties一文使得三元闭包性质变得流行。 &amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; 在这一文章中，他综合了弗里茨·海德 Fritz Heider于1946年提出的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;认知平衡 Cognitive Balance &amp;lt;/font&amp;gt;'''理论以及Georg Simmel对社会网络的理解。 一般而言，认知平衡是指两个个体对同一事物具有产生相同感觉的倾向。 如果三个个体所组成的三元组没有闭合，那么与同一个体联系的其余两个个体均将想要闭合这一三元组，进而在关系网络中形成闭包。&lt;br /&gt;
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==Measurements==&lt;br /&gt;
{{Unreferenced section|date=September 2009}}&lt;br /&gt;
The two most common measures of triadic closure for a graph are (in no particular order) the [[clustering coefficient]] and transitivity for that graph.&lt;br /&gt;
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The two most common measures of triadic closure for a graph are (in no particular order) the clustering coefficient and transitivity for that graph.&lt;br /&gt;
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==测量==&lt;br /&gt;
最常见的测量一张'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;图 Graph&amp;lt;/font&amp;gt;'''的三元闭包性质的两种方法（排名不分先后）是采用该图的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;聚集系数 Clustering Coefficient &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;传递性 Transitivity&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Clustering coefficient==&lt;br /&gt;
==聚集系数==&lt;br /&gt;
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One measure for the presence of triadic closure is [[clustering coefficient]], as follows:&lt;br /&gt;
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One measure for the presence of triadic closure is clustering coefficient, as follows:&lt;br /&gt;
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测量三元闭包是否出现的方法之一是聚集系数，如下所示：&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the [[degree (graph theory)|degree]] of vertex i.&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the degree of vertex i.&lt;br /&gt;
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令&amp;lt;math&amp;gt;G =(V，E)&amp;lt;/math&amp;gt;是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;无向简单图 Undirected Simple Graph&amp;lt;/font&amp;gt;'''（即，没有'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;自环 Self-loops&amp;lt;/font&amp;gt;'''或'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;多重边 Multiple Edges&amp;lt;/font&amp;gt;'''的图），其中&amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点 Vertice&amp;lt;/font&amp;gt;'''集，&amp;lt;math&amp;gt;E&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;边 Edge&amp;lt;/font&amp;gt;'''集。 另外，令&amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt;分别表示图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中顶点和边的数量，并令&amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; 表示顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;度 Degree&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
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我们可以通过边集&amp;lt;math&amp;gt;((i,j),(j,k),(i,k))&amp;lt;/math&amp;gt;，将由顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;,&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt;组成的三元组定义为一个三角形。&lt;br /&gt;
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We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
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We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
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我们也可以将顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量定义为&amp;lt;math&amp;gt;\delta(i)&amp;lt;/math&amp;gt;，并且由于每个三角形都被计数了三次，我们可以将图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中三角形的个数表达为&amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
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Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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假设三元闭包性质成立，则一个三元组仅需要两条强联系便可形成三角形。 因此，在三元闭包性质成立的前提下，理论上顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量为&amp;lt;math&amp;gt;\tau(i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;，假设&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;。我们可以表示&amp;lt;math&amp;gt;\tau(G) = \frac{1}{3} \sum_{i\in V} \ \tau(i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
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Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the [[clustering coefficient]] &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the [[clustering coefficient]] &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
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Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the clustering coefficient &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the clustering coefficient &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
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现在，对于具有&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;的顶点，顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的聚集系数是其拥有的三角形的占比，即&amp;lt;math&amp;gt;\frac{\delta(i)}{\tau(i)}&amp;lt;/math&amp;gt;。 因此，图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;的聚集系数&amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt;由&amp;lt;math&amp;gt; C(G)=\frac {1}{N_2} \sum_{i \in V,d_i \ge 2}c(i)&amp;lt;/math&amp;gt;给出，其中&amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt;是度至少为2的顶点数量。&lt;br /&gt;
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==Transitivity==&lt;br /&gt;
==传递性==&lt;br /&gt;
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Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
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Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
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测量三元闭包是否出现的另一方法是传递性，定义为&amp;lt;math&amp;gt;T(G)= \frac{3\delta(G)}{\tau(G)}&amp;lt;/math&amp;gt;。&lt;br /&gt;
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==Causes and effects==&lt;br /&gt;
==形成及其影响==&lt;br /&gt;
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In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
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In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&lt;br /&gt;
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在一个信任网络中，三元闭包性质的出现往往是由于传递性。如果节点A信任节点B，并且节点B信任节点C，则节点A将具有信任节点C的基础。在社会网络中，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强三元闭包 Strong Triadic Closure&amp;lt;/font&amp;gt;'''性质的出现往往是由于节点A与节点C拥有共同邻居节点B，在此情况下，节点A与节点C相遇的机会将会增加，进而至少产生一条'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;弱联系 Weak Tie&amp;lt;/font&amp;gt;'''。此外，由于两段分离的关系所带来的潜在压力，节点B也具有将节点A和节点C聚在一起的动机。&lt;br /&gt;
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Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
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Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
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遵循此原理的网络将高度互连且具有极高的聚集系数。 与此相反，不遵循该原理的网络的连通性则较差，且一旦包含负面关系，网络则可能会变得较不稳定。&lt;br /&gt;
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Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
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Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&lt;br /&gt;
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三元闭包是分析网络如何随时间演变的一个良好模型。 '''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;简单图论 Simple Graph Theory&amp;lt;/font&amp;gt;'''倾向于在某个时点分析网络，而应用三元闭包原理则可以预测网络中联系的形成，以及网络连通性的发展。&lt;br /&gt;
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In [[social networks]], triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
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In social networks, triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
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在社会网络中，三元闭包将促进合作行为，但是在新联系是通过现存联系而产生的情况下，平均而言个体所拥有的合作伙伴相对数量将小于个体在总体中随机选择合作伙伴时所拥有的合作伙伴相对数量。这一现象的产生可以从结构与信息两个角度进行解释。基于结构角度而言，网络具有高度聚集性的倾向。基于信息角度而言，我们通常假设，相较于随机的陌生人，个体对朋友的朋友有所了解。&lt;br /&gt;
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==Strong Triadic Closure Property and local bridges==&lt;br /&gt;
==强三元闭包性和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;局部桥 Local Bridges &amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A [[local bridge]] occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
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Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A local bridge occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
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强三元闭包性指，如果一个节点与两个邻居具有强联系，则这些邻居之间必须至少有一条弱联系。另一方面，当某节点在两个互不相连的邻居间充当'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;中间人 Gatekeeper&amp;lt;/font&amp;gt;'''时，则将产生局部桥。在遵循强三元闭包性质的网络中，局部桥涉及的节点之间的联系必然至少包括一条弱联系。&lt;br /&gt;
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==Proof by contradiction==&lt;br /&gt;
==反证法==&lt;br /&gt;
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Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&lt;br /&gt;
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假设节点B是节点A和C之间的局部桥，则所涉及的节点之间没有弱联系。 如果B与A和C之间均具有强联系，则根据强三元闭包性质的定义，节点A和C之间将形成弱联系。但是，这与B是局部桥的事实相矛盾。 因此，局部桥涉及的至少一个节点需要是弱联系，以防止三元闭包的产生。&lt;br /&gt;
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==References==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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{{Social networking}}&lt;br /&gt;
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[[Category:Social systems]]&lt;br /&gt;
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Category:Social systems&lt;br /&gt;
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类别: 社会系统&lt;br /&gt;
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[[Category:Sociological terminology]]&lt;br /&gt;
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Category:Sociological terminology&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Triadic closure]]. Its edit history can be viewed at [[三元闭包/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E4%B8%89%E5%85%83%E9%97%AD%E5%8C%85&amp;diff=16560</id>
		<title>三元闭包</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E4%B8%89%E5%85%83%E9%97%AD%E5%8C%85&amp;diff=16560"/>
		<updated>2020-10-22T12:04:45Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* Strong Triadic Closure Property and local bridges */&lt;/p&gt;
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&lt;div&gt;本词条由信白初步翻译&lt;br /&gt;
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'''Triadic closure''' is a concept in [[social network]] theory, first suggested by [[Germany|German]] [[sociology|sociologist]] [[Georg Simmel]] in his 1908 book ''Soziologie'' [''Sociology: Investigations on the Forms of Sociation''].&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C.&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Triadic closure is a concept in social network theory, first suggested by German sociologist Georg Simmel in his 1908 book Soziologie [Sociology: Investigations on the Forms of Sociation]. Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C. This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包 Triadic Closure &amp;lt;/font&amp;gt;'''是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;社会网络 Social Network&amp;lt;/font&amp;gt;'''理论中的一个概念，最早由德国社会学家格奥尔格·西梅尔 Georg Simmel在其1908年的著作《社会学：社会形式的调查》 Sociology: Investigations on the Forms of Sociation中提出。&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt;三元闭包指的是由A，B，C三个'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点 Node&amp;lt;/font&amp;gt;'''所组成的三元组的一种性质，即如果A-B和A-C之间存在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强联系 Strong Tie &amp;lt;/font&amp;gt;'''，则B-C之间也仅存在强联系。&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; 这一性质过于极端，以至于它难以在规模较大、结构复杂的网络中被满足，然而在理解网络与网络预测等方面，它却是一种十分有用的对现实的简化。&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==History==&lt;br /&gt;
Triadic closure was made popular by [[Mark Granovetter]] in his 1973 article ''The Strength of Weak Ties''.&amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; There he synthesized the theory of [[cognitive balance]] first introduced by [[Fritz Heider]] in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
&lt;br /&gt;
Triadic closure was made popular by Mark Granovetter in his 1973 article The Strength of Weak Ties. There he synthesized the theory of cognitive balance first introduced by Fritz Heider in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
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==历史==&lt;br /&gt;
马克·格兰诺维特 Mark Granovetter在1973年发表的《弱链接的力量》 The Strength of Weak Ties一文使得三元闭包性质变得流行。 &amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; 在这一文章中，他综合了弗里茨·海德 Fritz Heider于1946年提出的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;认知平衡 Cognitive Balance &amp;lt;/font&amp;gt;'''理论以及Georg Simmel对社会网络的理解。 一般而言，认知平衡是指两个个体对同一事物具有产生相同感觉的倾向。 如果三个个体所组成的三元组没有闭合，那么与同一个体联系的其余两个个体均将想要闭合这一三元组，进而在关系网络中形成闭包。&lt;br /&gt;
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==Measurements==&lt;br /&gt;
{{Unreferenced section|date=September 2009}}&lt;br /&gt;
The two most common measures of triadic closure for a graph are (in no particular order) the [[clustering coefficient]] and transitivity for that graph.&lt;br /&gt;
&lt;br /&gt;
The two most common measures of triadic closure for a graph are (in no particular order) the clustering coefficient and transitivity for that graph.&lt;br /&gt;
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==测量==&lt;br /&gt;
最常见的测量一张'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;图 Graph&amp;lt;/font&amp;gt;'''的三元闭包性质的两种方法（排名不分先后）是采用该图的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;聚集系数 Clustering Coefficient &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;传递性 Transitivity&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Clustering coefficient==&lt;br /&gt;
==聚集系数==&lt;br /&gt;
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One measure for the presence of triadic closure is [[clustering coefficient]], as follows:&lt;br /&gt;
&lt;br /&gt;
One measure for the presence of triadic closure is clustering coefficient, as follows:&lt;br /&gt;
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测量三元闭包是否出现的方法之一是聚集系数，如下所示：&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the [[degree (graph theory)|degree]] of vertex i.&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the degree of vertex i.&lt;br /&gt;
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令&amp;lt;math&amp;gt;G =(V，E)&amp;lt;/math&amp;gt;是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;无向简单图 Undirected Simple Graph&amp;lt;/font&amp;gt;'''（即，没有'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;自环 Self-loops&amp;lt;/font&amp;gt;'''或'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;多重边 Multiple Edges&amp;lt;/font&amp;gt;'''的图），其中&amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点 Vertice&amp;lt;/font&amp;gt;'''集，&amp;lt;math&amp;gt;E&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;边 Edge&amp;lt;/font&amp;gt;'''集。 另外，令&amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt;分别表示图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中顶点和边的数量，并令&amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; 表示顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;度 Degree&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
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我们可以通过边集&amp;lt;math&amp;gt;((i,j),(j,k),(i,k))&amp;lt;/math&amp;gt;，将由顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;,&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt;组成的三元组定义为一个三角形。&lt;br /&gt;
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We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
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We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
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我们也可以将顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量定义为&amp;lt;math&amp;gt;\delta(i)&amp;lt;/math&amp;gt;，并且由于每个三角形都被计数了三次，我们可以将图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中三角形的个数表达为&amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
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Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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假设三元闭包性质成立，则一个三元组仅需要两条强联系便可形成三角形。 因此，在三元闭包性质成立的前提下，理论上顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量为&amp;lt;math&amp;gt;\tau(i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;，假设&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;。我们可以表示&amp;lt;math&amp;gt;\tau(G) = \frac{1}{3} \sum_{i\in V} \ \tau(i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
&lt;br /&gt;
Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the [[clustering coefficient]] &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the [[clustering coefficient]] &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
&lt;br /&gt;
Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the clustering coefficient &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the clustering coefficient &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
&lt;br /&gt;
现在，对于具有&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;的顶点，顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的聚集系数是其拥有的三角形的占比，即&amp;lt;math&amp;gt;\frac{\delta(i)}{\tau(i)}&amp;lt;/math&amp;gt;。 因此，图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;的聚集系数&amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt;由&amp;lt;math&amp;gt; C(G)=\frac {1}{N_2} \sum_{i \in V,d_i \ge 2}c(i)&amp;lt;/math&amp;gt;给出，其中&amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt;是度至少为2的顶点数量。&lt;br /&gt;
&lt;br /&gt;
==Transitivity==&lt;br /&gt;
==传递性==&lt;br /&gt;
&lt;br /&gt;
Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
测量三元闭包是否出现的另一方法是传递性，定义为&amp;lt;math&amp;gt;T(G)= \frac{3\delta(G)}{\tau(G)}&amp;lt;/math&amp;gt;。&lt;br /&gt;
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==Causes and effects==&lt;br /&gt;
==形成及其影响==&lt;br /&gt;
&lt;br /&gt;
In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
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In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&lt;br /&gt;
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在一个信任网络中，三元闭包性质的出现往往是由于传递性。如果节点A信任节点B，并且节点B信任节点C，则节点A将具有信任节点C的基础。在社会网络中，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强三元闭包 Strong Triadic Closure&amp;lt;/font&amp;gt;'''性质的出现往往是由于节点A与节点C拥有共同邻居节点B，在此情况下，节点A与节点C相遇的机会将会增加，进而至少产生一条'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;弱联系 Weak Tie&amp;lt;/font&amp;gt;'''。此外，由于两段分离的关系所带来的潜在压力，节点B也具有将节点A和节点C聚在一起的动机。&lt;br /&gt;
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Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
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Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
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遵循此原理的网络将高度互连且具有极高的聚集系数。 与此相反，不遵循该原理的网络的连通性则较差，且一旦包含负面关系，网络则可能会变得较不稳定。&lt;br /&gt;
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Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
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Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&lt;br /&gt;
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三元闭包是分析网络如何随时间演变的一个良好模型。 '''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;简单图论 Simple Graph Theory&amp;lt;/font&amp;gt;'''倾向于在某个时点分析网络，而应用三元闭包原理则可以预测网络中联系的形成，以及网络连通性的发展。&lt;br /&gt;
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In [[social networks]], triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
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In social networks, triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
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在社会网络中，三元闭包将促进合作行为，但是在新联系是通过现存联系而产生的情况下，平均而言个体所拥有的合作伙伴相对数量将小于个体在总体中随机选择合作伙伴时所拥有的合作伙伴相对数量。这一现象的产生可以从结构与信息两个角度进行解释。基于结构角度而言，网络具有高度聚集性的倾向。基于信息角度而言，我们通常假设，相较于随机的陌生人，个体对朋友的朋友有所了解。&lt;br /&gt;
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==Strong Triadic Closure Property and local bridges==&lt;br /&gt;
==强三元闭包性和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;局部桥 Local Bridges &amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A [[local bridge]] occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
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Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A local bridge occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
&lt;br /&gt;
强三元闭包性指，如果一个节点与两个邻居具有强联系，则这些邻居之间必须至少有一条弱联系。另一方面，当某节点在两个互不相连的邻居间充当'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;中间人 Gatekeeper&amp;lt;/font&amp;gt;'''时，则将产生局部桥。在遵循强三元闭包性质的网络中，局部桥涉及的节点之间的联系必然至少包括一条弱联系。&lt;br /&gt;
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==Proof by contradiction==&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;矛盾证明 Proof By Contradiction &amp;lt;/font&amp;gt;'''&amp;lt;br&amp;gt;&lt;br /&gt;
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Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&lt;br /&gt;
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假设节点B是节点A和C之间的本地桥梁，以使所涉及的节点之间没有弱联系。 因此，B与A和C都具有牢固的联系。根据“强三元闭包性”的定义，节点A和C之间将形成弱联系。但是，这与B是本地网守的事实相矛盾。 因此，本地网桥中涉及的至少一个节点需要是弱连接，以防止三元闭包的发生。&lt;br /&gt;
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==References==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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{{Social networking}}&lt;br /&gt;
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{{DEFAULTSORT:Triadic Closure}}&lt;br /&gt;
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[[Category:Social systems]]&lt;br /&gt;
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Category:Social systems&lt;br /&gt;
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类别: 社会系统&lt;br /&gt;
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[[Category:Sociological terminology]]&lt;br /&gt;
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Category:Sociological terminology&lt;br /&gt;
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类别: 社会学术语&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Triadic closure]]. Its edit history can be viewed at [[三元闭包/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E4%B8%89%E5%85%83%E9%97%AD%E5%8C%85&amp;diff=16559</id>
		<title>三元闭包</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E4%B8%89%E5%85%83%E9%97%AD%E5%8C%85&amp;diff=16559"/>
		<updated>2020-10-22T11:54:47Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* 形成及其影响 */&lt;/p&gt;
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&lt;div&gt;本词条由信白初步翻译&lt;br /&gt;
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'''Triadic closure''' is a concept in [[social network]] theory, first suggested by [[Germany|German]] [[sociology|sociologist]] [[Georg Simmel]] in his 1908 book ''Soziologie'' [''Sociology: Investigations on the Forms of Sociation''].&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C.&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Triadic closure is a concept in social network theory, first suggested by German sociologist Georg Simmel in his 1908 book Soziologie [Sociology: Investigations on the Forms of Sociation]. Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C. This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包 Triadic Closure &amp;lt;/font&amp;gt;'''是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;社会网络 Social Network&amp;lt;/font&amp;gt;'''理论中的一个概念，最早由德国社会学家格奥尔格·西梅尔 Georg Simmel在其1908年的著作《社会学：社会形式的调查》 Sociology: Investigations on the Forms of Sociation中提出。&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt;三元闭包指的是由A，B，C三个'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点 Node&amp;lt;/font&amp;gt;'''所组成的三元组的一种性质，即如果A-B和A-C之间存在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强联系 Strong Tie &amp;lt;/font&amp;gt;'''，则B-C之间也仅存在强联系。&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; 这一性质过于极端，以至于它难以在规模较大、结构复杂的网络中被满足，然而在理解网络与网络预测等方面，它却是一种十分有用的对现实的简化。&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==History==&lt;br /&gt;
Triadic closure was made popular by [[Mark Granovetter]] in his 1973 article ''The Strength of Weak Ties''.&amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; There he synthesized the theory of [[cognitive balance]] first introduced by [[Fritz Heider]] in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
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Triadic closure was made popular by Mark Granovetter in his 1973 article The Strength of Weak Ties. There he synthesized the theory of cognitive balance first introduced by Fritz Heider in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
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==历史==&lt;br /&gt;
马克·格兰诺维特 Mark Granovetter在1973年发表的《弱链接的力量》 The Strength of Weak Ties一文使得三元闭包性质变得流行。 &amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; 在这一文章中，他综合了弗里茨·海德 Fritz Heider于1946年提出的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;认知平衡 Cognitive Balance &amp;lt;/font&amp;gt;'''理论以及Georg Simmel对社会网络的理解。 一般而言，认知平衡是指两个个体对同一事物具有产生相同感觉的倾向。 如果三个个体所组成的三元组没有闭合，那么与同一个体联系的其余两个个体均将想要闭合这一三元组，进而在关系网络中形成闭包。&lt;br /&gt;
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==Measurements==&lt;br /&gt;
{{Unreferenced section|date=September 2009}}&lt;br /&gt;
The two most common measures of triadic closure for a graph are (in no particular order) the [[clustering coefficient]] and transitivity for that graph.&lt;br /&gt;
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The two most common measures of triadic closure for a graph are (in no particular order) the clustering coefficient and transitivity for that graph.&lt;br /&gt;
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==测量==&lt;br /&gt;
最常见的测量一张'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;图 Graph&amp;lt;/font&amp;gt;'''的三元闭包性质的两种方法（排名不分先后）是采用该图的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;聚集系数 Clustering Coefficient &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;传递性 Transitivity&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Clustering coefficient==&lt;br /&gt;
==聚集系数==&lt;br /&gt;
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One measure for the presence of triadic closure is [[clustering coefficient]], as follows:&lt;br /&gt;
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One measure for the presence of triadic closure is clustering coefficient, as follows:&lt;br /&gt;
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测量三元闭包是否出现的方法之一是聚集系数，如下所示：&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the [[degree (graph theory)|degree]] of vertex i.&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the degree of vertex i.&lt;br /&gt;
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令&amp;lt;math&amp;gt;G =(V，E)&amp;lt;/math&amp;gt;是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;无向简单图 Undirected Simple Graph&amp;lt;/font&amp;gt;'''（即，没有'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;自环 Self-loops&amp;lt;/font&amp;gt;'''或'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;多重边 Multiple Edges&amp;lt;/font&amp;gt;'''的图），其中&amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点 Vertice&amp;lt;/font&amp;gt;'''集，&amp;lt;math&amp;gt;E&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;边 Edge&amp;lt;/font&amp;gt;'''集。 另外，令&amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt;分别表示图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中顶点和边的数量，并令&amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; 表示顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;度 Degree&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
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我们可以通过边集&amp;lt;math&amp;gt;((i,j),(j,k),(i,k))&amp;lt;/math&amp;gt;，将由顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;,&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt;组成的三元组定义为一个三角形。&lt;br /&gt;
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We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
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We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
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我们也可以将顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量定义为&amp;lt;math&amp;gt;\delta(i)&amp;lt;/math&amp;gt;，并且由于每个三角形都被计数了三次，我们可以将图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中三角形的个数表达为&amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
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Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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假设三元闭包性质成立，则一个三元组仅需要两条强联系便可形成三角形。 因此，在三元闭包性质成立的前提下，理论上顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量为&amp;lt;math&amp;gt;\tau(i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;，假设&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;。我们可以表示&amp;lt;math&amp;gt;\tau(G) = \frac{1}{3} \sum_{i\in V} \ \tau(i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
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Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the [[clustering coefficient]] &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the [[clustering coefficient]] &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
&lt;br /&gt;
Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the clustering coefficient &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the clustering coefficient &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
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现在，对于具有&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;的顶点，顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的聚集系数是其拥有的三角形的占比，即&amp;lt;math&amp;gt;\frac{\delta(i)}{\tau(i)}&amp;lt;/math&amp;gt;。 因此，图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;的聚集系数&amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt;由&amp;lt;math&amp;gt; C(G)=\frac {1}{N_2} \sum_{i \in V,d_i \ge 2}c(i)&amp;lt;/math&amp;gt;给出，其中&amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt;是度至少为2的顶点数量。&lt;br /&gt;
&lt;br /&gt;
==Transitivity==&lt;br /&gt;
==传递性==&lt;br /&gt;
&lt;br /&gt;
Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
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测量三元闭包是否出现的另一方法是传递性，定义为&amp;lt;math&amp;gt;T(G)= \frac{3\delta(G)}{\tau(G)}&amp;lt;/math&amp;gt;。&lt;br /&gt;
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==Causes and effects==&lt;br /&gt;
==形成及其影响==&lt;br /&gt;
&lt;br /&gt;
In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
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In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&lt;br /&gt;
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在一个信任网络中，三元闭包性质的出现往往是由于传递性。如果节点A信任节点B，并且节点B信任节点C，则节点A将具有信任节点C的基础。在社会网络中，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强三元闭包 Strong Triadic Closure&amp;lt;/font&amp;gt;'''性质的出现往往是由于节点A与节点C拥有共同邻居节点B，在此情况下，节点A与节点C相遇的机会将会增加，进而至少产生一条'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;弱联系 Weak Tie&amp;lt;/font&amp;gt;'''。此外，由于两段分离的关系所带来的潜在压力，节点B也具有将节点A和节点C聚在一起的动机。&lt;br /&gt;
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Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
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Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
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遵循此原理的网络将高度互连且具有极高的聚集系数。 与此相反，不遵循该原理的网络的连通性则较差，且一旦包含负面关系，网络则可能会变得较不稳定。&lt;br /&gt;
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Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
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Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&lt;br /&gt;
&lt;br /&gt;
三元闭包是分析网络如何随时间演变的一个良好模型。 '''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;简单图论 Simple Graph Theory&amp;lt;/font&amp;gt;'''倾向于在某个时点分析网络，而应用三元闭包原理则可以预测网络中联系的形成，以及网络连通性的发展。&lt;br /&gt;
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In [[social networks]], triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
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In social networks, triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
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在社会网络中，三元闭包将促进合作行为，但是在新联系是通过现存联系而产生的情况下，平均而言个体所拥有的合作伙伴相对数量将小于个体在总体中随机选择合作伙伴时所拥有的合作伙伴相对数量。这一现象的产生可以从结构与信息两个角度进行解释。基于结构角度而言，网络具有高度聚集性的倾向。基于信息角度而言，我们通常假设，相较于随机的陌生人，个体对朋友的朋友有所了解。&lt;br /&gt;
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==Strong Triadic Closure Property and local bridges==&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强三元闭包性 Strong Triadic Closure Property &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;本地网桥 Local Bridges &amp;lt;/font&amp;gt;'''&amp;lt;br&amp;gt;&lt;br /&gt;
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Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A [[local bridge]] occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
&lt;br /&gt;
Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A local bridge occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
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强三元闭包性是，如果一个节点与两个邻居有牢固的联系，则这些邻居之间必须至少有一条弱联系。 另一方面，当节点充当两个其他未连接的相邻节点之间的网守时，则发生本地网桥。 在遵循“强三元闭合性”的网络中，本地网桥中涉及的节点之间的联系之一必须是弱联系。&lt;br /&gt;
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==Proof by contradiction==&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;矛盾证明 Proof By Contradiction &amp;lt;/font&amp;gt;'''&amp;lt;br&amp;gt;&lt;br /&gt;
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Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&lt;br /&gt;
&lt;br /&gt;
假设节点B是节点A和C之间的本地桥梁，以使所涉及的节点之间没有弱联系。 因此，B与A和C都具有牢固的联系。根据“强三元闭包性”的定义，节点A和C之间将形成弱联系。但是，这与B是本地网守的事实相矛盾。 因此，本地网桥中涉及的至少一个节点需要是弱连接，以防止三元闭包的发生。&lt;br /&gt;
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==References==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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{{Social networking}}&lt;br /&gt;
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{{DEFAULTSORT:Triadic Closure}}&lt;br /&gt;
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[[Category:Social systems]]&lt;br /&gt;
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Category:Social systems&lt;br /&gt;
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类别: 社会系统&lt;br /&gt;
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[[Category:Sociological terminology]]&lt;br /&gt;
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Category:Sociological terminology&lt;br /&gt;
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类别: 社会学术语&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Triadic closure]]. Its edit history can be viewed at [[三元闭包/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
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		<title>三元闭包</title>
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		<updated>2020-10-22T11:36:46Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* 形成及其影响 */&lt;/p&gt;
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&lt;div&gt;本词条由信白初步翻译&lt;br /&gt;
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'''Triadic closure''' is a concept in [[social network]] theory, first suggested by [[Germany|German]] [[sociology|sociologist]] [[Georg Simmel]] in his 1908 book ''Soziologie'' [''Sociology: Investigations on the Forms of Sociation''].&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C.&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Triadic closure is a concept in social network theory, first suggested by German sociologist Georg Simmel in his 1908 book Soziologie [Sociology: Investigations on the Forms of Sociation]. Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C. This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包 Triadic Closure &amp;lt;/font&amp;gt;'''是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;社会网络 Social Network&amp;lt;/font&amp;gt;'''理论中的一个概念，最早由德国社会学家格奥尔格·西梅尔 Georg Simmel在其1908年的著作《社会学：社会形式的调查》 Sociology: Investigations on the Forms of Sociation中提出。&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt;三元闭包指的是由A，B，C三个'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点 Node&amp;lt;/font&amp;gt;'''所组成的三元组的一种性质，即如果A-B和A-C之间存在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强联系 Strong Tie &amp;lt;/font&amp;gt;'''，则B-C之间也仅存在强联系。&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; 这一性质过于极端，以至于它难以在规模较大、结构复杂的网络中被满足，然而在理解网络与网络预测等方面，它却是一种十分有用的对现实的简化。&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==History==&lt;br /&gt;
Triadic closure was made popular by [[Mark Granovetter]] in his 1973 article ''The Strength of Weak Ties''.&amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; There he synthesized the theory of [[cognitive balance]] first introduced by [[Fritz Heider]] in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
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Triadic closure was made popular by Mark Granovetter in his 1973 article The Strength of Weak Ties. There he synthesized the theory of cognitive balance first introduced by Fritz Heider in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
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==历史==&lt;br /&gt;
马克·格兰诺维特 Mark Granovetter在1973年发表的《弱链接的力量》 The Strength of Weak Ties一文使得三元闭包性质变得流行。 &amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; 在这一文章中，他综合了弗里茨·海德 Fritz Heider于1946年提出的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;认知平衡 Cognitive Balance &amp;lt;/font&amp;gt;'''理论以及Georg Simmel对社会网络的理解。 一般而言，认知平衡是指两个个体对同一事物具有产生相同感觉的倾向。 如果三个个体所组成的三元组没有闭合，那么与同一个体联系的其余两个个体均将想要闭合这一三元组，进而在关系网络中形成闭包。&lt;br /&gt;
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==Measurements==&lt;br /&gt;
{{Unreferenced section|date=September 2009}}&lt;br /&gt;
The two most common measures of triadic closure for a graph are (in no particular order) the [[clustering coefficient]] and transitivity for that graph.&lt;br /&gt;
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The two most common measures of triadic closure for a graph are (in no particular order) the clustering coefficient and transitivity for that graph.&lt;br /&gt;
&lt;br /&gt;
==测量==&lt;br /&gt;
最常见的测量一张'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;图 Graph&amp;lt;/font&amp;gt;'''的三元闭包性质的两种方法（排名不分先后）是采用该图的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;聚集系数 Clustering Coefficient &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;传递性 Transitivity&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
&lt;br /&gt;
==Clustering coefficient==&lt;br /&gt;
==聚集系数==&lt;br /&gt;
&lt;br /&gt;
One measure for the presence of triadic closure is [[clustering coefficient]], as follows:&lt;br /&gt;
&lt;br /&gt;
One measure for the presence of triadic closure is clustering coefficient, as follows:&lt;br /&gt;
&lt;br /&gt;
测量三元闭包是否出现的方法之一是聚集系数，如下所示：&lt;br /&gt;
&lt;br /&gt;
Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the [[degree (graph theory)|degree]] of vertex i.&lt;br /&gt;
&lt;br /&gt;
Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the degree of vertex i.&lt;br /&gt;
&lt;br /&gt;
令&amp;lt;math&amp;gt;G =(V，E)&amp;lt;/math&amp;gt;是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;无向简单图 Undirected Simple Graph&amp;lt;/font&amp;gt;'''（即，没有'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;自环 Self-loops&amp;lt;/font&amp;gt;'''或'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;多重边 Multiple Edges&amp;lt;/font&amp;gt;'''的图），其中&amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点 Vertice&amp;lt;/font&amp;gt;'''集，&amp;lt;math&amp;gt;E&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;边 Edge&amp;lt;/font&amp;gt;'''集。 另外，令&amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt;分别表示图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中顶点和边的数量，并令&amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; 表示顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;度 Degree&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
&lt;br /&gt;
We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
&lt;br /&gt;
We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
&lt;br /&gt;
我们可以通过边集&amp;lt;math&amp;gt;((i,j),(j,k),(i,k))&amp;lt;/math&amp;gt;，将由顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;,&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt;组成的三元组定义为一个三角形。&lt;br /&gt;
&lt;br /&gt;
We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
我们也可以将顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量定义为&amp;lt;math&amp;gt;\delta(i)&amp;lt;/math&amp;gt;，并且由于每个三角形都被计数了三次，我们可以将图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中三角形的个数表达为&amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
&lt;br /&gt;
Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
假设三元闭包性质成立，则一个三元组仅需要两条强联系便可形成三角形。 因此，在三元闭包性质成立的前提下，理论上顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量为&amp;lt;math&amp;gt;\tau(i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;，假设&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;。我们可以表示&amp;lt;math&amp;gt;\tau(G) = \frac{1}{3} \sum_{i\in V} \ \tau(i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
&lt;br /&gt;
Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the [[clustering coefficient]] &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the [[clustering coefficient]] &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
&lt;br /&gt;
Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the clustering coefficient &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the clustering coefficient &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
&lt;br /&gt;
现在，对于具有&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;的顶点，顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的聚集系数是其拥有的三角形的占比，即&amp;lt;math&amp;gt;\frac{\delta(i)}{\tau(i)}&amp;lt;/math&amp;gt;。 因此，图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;的聚集系数&amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt;由&amp;lt;math&amp;gt; C(G)=\frac {1}{N_2} \sum_{i \in V,d_i \ge 2}c(i)&amp;lt;/math&amp;gt;给出，其中&amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt;是度至少为2的顶点数量。&lt;br /&gt;
&lt;br /&gt;
==Transitivity==&lt;br /&gt;
==传递性==&lt;br /&gt;
&lt;br /&gt;
Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
测量三元闭包是否出现的另一方法是传递性，定义为&amp;lt;math&amp;gt;T(G)= \frac{3\delta(G)}{\tau(G)}&amp;lt;/math&amp;gt;。&lt;br /&gt;
&lt;br /&gt;
==Causes and effects==&lt;br /&gt;
==形成及其影响==&lt;br /&gt;
&lt;br /&gt;
In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&lt;br /&gt;
&lt;br /&gt;
在一个信任网络中，三元闭包性质的出现往往是由于传递性。如果节点A信任节点B，并且节点B信任节点C，则节点A将具有信任节点C的基础。在社会网络中，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强三元闭包 Strong Triadic Closure&amp;lt;/font&amp;gt;'''性质的出现往往是由于'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''A与'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''C拥有共同邻居'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''B，因为他们相遇的机会将会增加进而至少产生一条'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;弱联系 Weak Tie&amp;lt;/font&amp;gt;'''。此外，由于两段分离的关系所带来的潜在压力，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''B也具有将'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''A和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''C聚在一起的动机。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
&lt;br /&gt;
Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
&lt;br /&gt;
遵循此原理的网络将高度互连且具有极高的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;聚集系数&amp;lt;/font&amp;gt;'''。 与此相反，不遵循该原理的网络的连通性则较差，且一旦包含负面关系，网络则可能会变得较不稳定。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''是分析网络如何随时间演变的一个良好模型。 '''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;简单图论 Simple Graph Theory&amp;lt;/font&amp;gt;'''倾向于在某个时点分析网络，而应用'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''原理则可以预测网络中联系的形成，以及网络连通性的发展。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
In [[social networks]], triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
&lt;br /&gt;
In social networks, triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
&lt;br /&gt;
在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;社会网络&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''将促进合作行为，但是当通过从现有联系中推荐人时，合作者的平均全球比例要小于个人从总体人口中随机选择新联系时的比例。 对此的两个可能的影响是结构和信息结构。 结构构造来自于倾向于高度可聚性的倾向。 信息结构来自这样一个假设：与随机的陌生人不同，一个人对朋友的朋友有所了解。&lt;br /&gt;
&lt;br /&gt;
==Strong Triadic Closure Property and local bridges==&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强三元闭包性 Strong Triadic Closure Property &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;本地网桥 Local Bridges &amp;lt;/font&amp;gt;'''&amp;lt;br&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A [[local bridge]] occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
&lt;br /&gt;
Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A local bridge occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
&lt;br /&gt;
强三元闭包性是，如果一个节点与两个邻居有牢固的联系，则这些邻居之间必须至少有一条弱联系。 另一方面，当节点充当两个其他未连接的相邻节点之间的网守时，则发生本地网桥。 在遵循“强三元闭合性”的网络中，本地网桥中涉及的节点之间的联系之一必须是弱联系。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Proof by contradiction==&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;矛盾证明 Proof By Contradiction &amp;lt;/font&amp;gt;'''&amp;lt;br&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&lt;br /&gt;
&lt;br /&gt;
假设节点B是节点A和C之间的本地桥梁，以使所涉及的节点之间没有弱联系。 因此，B与A和C都具有牢固的联系。根据“强三元闭包性”的定义，节点A和C之间将形成弱联系。但是，这与B是本地网守的事实相矛盾。 因此，本地网桥中涉及的至少一个节点需要是弱连接，以防止三元闭包的发生。&lt;br /&gt;
&lt;br /&gt;
==References==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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{{Social networking}}&lt;br /&gt;
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{{DEFAULTSORT:Triadic Closure}}&lt;br /&gt;
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[[Category:Social systems]]&lt;br /&gt;
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Category:Social systems&lt;br /&gt;
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类别: 社会系统&lt;br /&gt;
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[[Category:Sociological terminology]]&lt;br /&gt;
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Category:Sociological terminology&lt;br /&gt;
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类别: 社会学术语&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Triadic closure]]. Its edit history can be viewed at [[三元闭包/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E4%B8%89%E5%85%83%E9%97%AD%E5%8C%85&amp;diff=16554</id>
		<title>三元闭包</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E4%B8%89%E5%85%83%E9%97%AD%E5%8C%85&amp;diff=16554"/>
		<updated>2020-10-22T11:34:58Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* 传递性 Transitivity */&lt;/p&gt;
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&lt;div&gt;本词条由信白初步翻译&lt;br /&gt;
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'''Triadic closure''' is a concept in [[social network]] theory, first suggested by [[Germany|German]] [[sociology|sociologist]] [[Georg Simmel]] in his 1908 book ''Soziologie'' [''Sociology: Investigations on the Forms of Sociation''].&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C.&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Triadic closure is a concept in social network theory, first suggested by German sociologist Georg Simmel in his 1908 book Soziologie [Sociology: Investigations on the Forms of Sociation]. Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C. This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包 Triadic Closure &amp;lt;/font&amp;gt;'''是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;社会网络 Social Network&amp;lt;/font&amp;gt;'''理论中的一个概念，最早由德国社会学家格奥尔格·西梅尔 Georg Simmel在其1908年的著作《社会学：社会形式的调查》 Sociology: Investigations on the Forms of Sociation中提出。&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt;三元闭包指的是由A，B，C三个'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点 Node&amp;lt;/font&amp;gt;'''所组成的三元组的一种性质，即如果A-B和A-C之间存在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强联系 Strong Tie &amp;lt;/font&amp;gt;'''，则B-C之间也仅存在强联系。&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; 这一性质过于极端，以至于它难以在规模较大、结构复杂的网络中被满足，然而在理解网络与网络预测等方面，它却是一种十分有用的对现实的简化。&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==History==&lt;br /&gt;
Triadic closure was made popular by [[Mark Granovetter]] in his 1973 article ''The Strength of Weak Ties''.&amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; There he synthesized the theory of [[cognitive balance]] first introduced by [[Fritz Heider]] in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
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Triadic closure was made popular by Mark Granovetter in his 1973 article The Strength of Weak Ties. There he synthesized the theory of cognitive balance first introduced by Fritz Heider in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
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==历史==&lt;br /&gt;
马克·格兰诺维特 Mark Granovetter在1973年发表的《弱链接的力量》 The Strength of Weak Ties一文使得三元闭包性质变得流行。 &amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; 在这一文章中，他综合了弗里茨·海德 Fritz Heider于1946年提出的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;认知平衡 Cognitive Balance &amp;lt;/font&amp;gt;'''理论以及Georg Simmel对社会网络的理解。 一般而言，认知平衡是指两个个体对同一事物具有产生相同感觉的倾向。 如果三个个体所组成的三元组没有闭合，那么与同一个体联系的其余两个个体均将想要闭合这一三元组，进而在关系网络中形成闭包。&lt;br /&gt;
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==Measurements==&lt;br /&gt;
{{Unreferenced section|date=September 2009}}&lt;br /&gt;
The two most common measures of triadic closure for a graph are (in no particular order) the [[clustering coefficient]] and transitivity for that graph.&lt;br /&gt;
&lt;br /&gt;
The two most common measures of triadic closure for a graph are (in no particular order) the clustering coefficient and transitivity for that graph.&lt;br /&gt;
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==测量==&lt;br /&gt;
最常见的测量一张'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;图 Graph&amp;lt;/font&amp;gt;'''的三元闭包性质的两种方法（排名不分先后）是采用该图的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;聚集系数 Clustering Coefficient &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;传递性 Transitivity&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Clustering coefficient==&lt;br /&gt;
==聚集系数==&lt;br /&gt;
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One measure for the presence of triadic closure is [[clustering coefficient]], as follows:&lt;br /&gt;
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One measure for the presence of triadic closure is clustering coefficient, as follows:&lt;br /&gt;
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测量三元闭包是否出现的方法之一是聚集系数，如下所示：&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the [[degree (graph theory)|degree]] of vertex i.&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the degree of vertex i.&lt;br /&gt;
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令&amp;lt;math&amp;gt;G =(V，E)&amp;lt;/math&amp;gt;是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;无向简单图 Undirected Simple Graph&amp;lt;/font&amp;gt;'''（即，没有'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;自环 Self-loops&amp;lt;/font&amp;gt;'''或'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;多重边 Multiple Edges&amp;lt;/font&amp;gt;'''的图），其中&amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点 Vertice&amp;lt;/font&amp;gt;'''集，&amp;lt;math&amp;gt;E&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;边 Edge&amp;lt;/font&amp;gt;'''集。 另外，令&amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt;分别表示图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中顶点和边的数量，并令&amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; 表示顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;度 Degree&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
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我们可以通过边集&amp;lt;math&amp;gt;((i,j),(j,k),(i,k))&amp;lt;/math&amp;gt;，将由顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;,&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt;组成的三元组定义为一个三角形。&lt;br /&gt;
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We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
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We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
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我们也可以将顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量定义为&amp;lt;math&amp;gt;\delta(i)&amp;lt;/math&amp;gt;，并且由于每个三角形都被计数了三次，我们可以将图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中三角形的个数表达为&amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
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Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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假设三元闭包性质成立，则一个三元组仅需要两条强联系便可形成三角形。 因此，在三元闭包性质成立的前提下，理论上顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量为&amp;lt;math&amp;gt;\tau(i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;，假设&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;。我们可以表示&amp;lt;math&amp;gt;\tau(G) = \frac{1}{3} \sum_{i\in V} \ \tau(i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
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Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the [[clustering coefficient]] &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the [[clustering coefficient]] &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
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Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the clustering coefficient &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the clustering coefficient &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
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现在，对于具有&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;的顶点，顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的聚集系数是其拥有的三角形的占比，即&amp;lt;math&amp;gt;\frac{\delta(i)}{\tau(i)}&amp;lt;/math&amp;gt;。 因此，图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;的聚集系数&amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt;由&amp;lt;math&amp;gt; C(G)=\frac {1}{N_2} \sum_{i \in V,d_i \ge 2}c(i)&amp;lt;/math&amp;gt;给出，其中&amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt;是度至少为2的顶点数量。&lt;br /&gt;
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==Transitivity==&lt;br /&gt;
==传递性==&lt;br /&gt;
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Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
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Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
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测量三元闭包是否出现的另一方法是传递性，定义为&amp;lt;math&amp;gt;T(G)= \frac{3\delta(G)}{\tau(G)}&amp;lt;/math&amp;gt;。&lt;br /&gt;
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==Causes and effects==&lt;br /&gt;
==形成及其影响==&lt;br /&gt;
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In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
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In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&lt;br /&gt;
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在一个信任网络中，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''性质的出现往往是由于'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;传递性&amp;lt;/font&amp;gt;'''。如果'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''A信任'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''B，并且'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''B信任'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''C，则'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''A将具有信任'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''C的基础。在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;社会网络&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强三元闭包 Strong Triadic Closure&amp;lt;/font&amp;gt;'''性质的出现往往是由于'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''A与'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''C拥有共同邻居'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''B，因为他们相遇的机会将会增加进而至少产生一条'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;弱联系 Weak Tie&amp;lt;/font&amp;gt;'''。此外，由于两段分离的关系所带来的潜在压力，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''B也具有将'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''A和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''C聚在一起的动机。&lt;br /&gt;
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Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
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Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
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遵循此原理的网络将高度互连且具有极高的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;聚集系数&amp;lt;/font&amp;gt;'''。 与此相反，不遵循该原理的网络的连通性则较差，且一旦包含负面关系，网络则可能会变得较不稳定。&lt;br /&gt;
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Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
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Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''是分析网络如何随时间演变的一个良好模型。 '''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;简单图论 Simple Graph Theory&amp;lt;/font&amp;gt;'''倾向于在某个时点分析网络，而应用'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''原理则可以预测网络中联系的形成，以及网络连通性的发展。&lt;br /&gt;
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In [[social networks]], triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
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In social networks, triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;社会网络&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''将促进合作行为，但是当通过从现有联系中推荐人时，合作者的平均全球比例要小于个人从总体人口中随机选择新联系时的比例。 对此的两个可能的影响是结构和信息结构。 结构构造来自于倾向于高度可聚性的倾向。 信息结构来自这样一个假设：与随机的陌生人不同，一个人对朋友的朋友有所了解。&lt;br /&gt;
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==Strong Triadic Closure Property and local bridges==&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强三元闭包性 Strong Triadic Closure Property &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;本地网桥 Local Bridges &amp;lt;/font&amp;gt;'''&amp;lt;br&amp;gt;&lt;br /&gt;
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Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A [[local bridge]] occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
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Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A local bridge occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
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强三元闭包性是，如果一个节点与两个邻居有牢固的联系，则这些邻居之间必须至少有一条弱联系。 另一方面，当节点充当两个其他未连接的相邻节点之间的网守时，则发生本地网桥。 在遵循“强三元闭合性”的网络中，本地网桥中涉及的节点之间的联系之一必须是弱联系。&lt;br /&gt;
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==Proof by contradiction==&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;矛盾证明 Proof By Contradiction &amp;lt;/font&amp;gt;'''&amp;lt;br&amp;gt;&lt;br /&gt;
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Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
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Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&lt;br /&gt;
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假设节点B是节点A和C之间的本地桥梁，以使所涉及的节点之间没有弱联系。 因此，B与A和C都具有牢固的联系。根据“强三元闭包性”的定义，节点A和C之间将形成弱联系。但是，这与B是本地网守的事实相矛盾。 因此，本地网桥中涉及的至少一个节点需要是弱连接，以防止三元闭包的发生。&lt;br /&gt;
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==References==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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{{Social networking}}&lt;br /&gt;
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{{DEFAULTSORT:Triadic Closure}}&lt;br /&gt;
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[[Category:Social systems]]&lt;br /&gt;
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Category:Social systems&lt;br /&gt;
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类别: 社会系统&lt;br /&gt;
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[[Category:Sociological terminology]]&lt;br /&gt;
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Category:Sociological terminology&lt;br /&gt;
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类别: 社会学术语&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Triadic closure]]. Its edit history can be viewed at [[三元闭包/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
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	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E4%B8%89%E5%85%83%E9%97%AD%E5%8C%85&amp;diff=16553</id>
		<title>三元闭包</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E4%B8%89%E5%85%83%E9%97%AD%E5%8C%85&amp;diff=16553"/>
		<updated>2020-10-22T11:34:23Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* 聚集系数 */&lt;/p&gt;
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&lt;div&gt;本词条由信白初步翻译&lt;br /&gt;
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'''Triadic closure''' is a concept in [[social network]] theory, first suggested by [[Germany|German]] [[sociology|sociologist]] [[Georg Simmel]] in his 1908 book ''Soziologie'' [''Sociology: Investigations on the Forms of Sociation''].&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C.&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Triadic closure is a concept in social network theory, first suggested by German sociologist Georg Simmel in his 1908 book Soziologie [Sociology: Investigations on the Forms of Sociation]. Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C. This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包 Triadic Closure &amp;lt;/font&amp;gt;'''是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;社会网络 Social Network&amp;lt;/font&amp;gt;'''理论中的一个概念，最早由德国社会学家格奥尔格·西梅尔 Georg Simmel在其1908年的著作《社会学：社会形式的调查》 Sociology: Investigations on the Forms of Sociation中提出。&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt;三元闭包指的是由A，B，C三个'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点 Node&amp;lt;/font&amp;gt;'''所组成的三元组的一种性质，即如果A-B和A-C之间存在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强联系 Strong Tie &amp;lt;/font&amp;gt;'''，则B-C之间也仅存在强联系。&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; 这一性质过于极端，以至于它难以在规模较大、结构复杂的网络中被满足，然而在理解网络与网络预测等方面，它却是一种十分有用的对现实的简化。&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==History==&lt;br /&gt;
Triadic closure was made popular by [[Mark Granovetter]] in his 1973 article ''The Strength of Weak Ties''.&amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; There he synthesized the theory of [[cognitive balance]] first introduced by [[Fritz Heider]] in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
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Triadic closure was made popular by Mark Granovetter in his 1973 article The Strength of Weak Ties. There he synthesized the theory of cognitive balance first introduced by Fritz Heider in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
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==历史==&lt;br /&gt;
马克·格兰诺维特 Mark Granovetter在1973年发表的《弱链接的力量》 The Strength of Weak Ties一文使得三元闭包性质变得流行。 &amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; 在这一文章中，他综合了弗里茨·海德 Fritz Heider于1946年提出的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;认知平衡 Cognitive Balance &amp;lt;/font&amp;gt;'''理论以及Georg Simmel对社会网络的理解。 一般而言，认知平衡是指两个个体对同一事物具有产生相同感觉的倾向。 如果三个个体所组成的三元组没有闭合，那么与同一个体联系的其余两个个体均将想要闭合这一三元组，进而在关系网络中形成闭包。&lt;br /&gt;
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==Measurements==&lt;br /&gt;
{{Unreferenced section|date=September 2009}}&lt;br /&gt;
The two most common measures of triadic closure for a graph are (in no particular order) the [[clustering coefficient]] and transitivity for that graph.&lt;br /&gt;
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The two most common measures of triadic closure for a graph are (in no particular order) the clustering coefficient and transitivity for that graph.&lt;br /&gt;
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==测量==&lt;br /&gt;
最常见的测量一张'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;图 Graph&amp;lt;/font&amp;gt;'''的三元闭包性质的两种方法（排名不分先后）是采用该图的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;聚集系数 Clustering Coefficient &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;传递性 Transitivity&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Clustering coefficient==&lt;br /&gt;
==聚集系数==&lt;br /&gt;
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One measure for the presence of triadic closure is [[clustering coefficient]], as follows:&lt;br /&gt;
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One measure for the presence of triadic closure is clustering coefficient, as follows:&lt;br /&gt;
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测量三元闭包是否出现的方法之一是聚集系数，如下所示：&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the [[degree (graph theory)|degree]] of vertex i.&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the degree of vertex i.&lt;br /&gt;
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令&amp;lt;math&amp;gt;G =(V，E)&amp;lt;/math&amp;gt;是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;无向简单图 Undirected Simple Graph&amp;lt;/font&amp;gt;'''（即，没有'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;自环 Self-loops&amp;lt;/font&amp;gt;'''或'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;多重边 Multiple Edges&amp;lt;/font&amp;gt;'''的图），其中&amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点 Vertice&amp;lt;/font&amp;gt;'''集，&amp;lt;math&amp;gt;E&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;边 Edge&amp;lt;/font&amp;gt;'''集。 另外，令&amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt;分别表示图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中顶点和边的数量，并令&amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; 表示顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;度 Degree&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
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我们可以通过边集&amp;lt;math&amp;gt;((i,j),(j,k),(i,k))&amp;lt;/math&amp;gt;，将由顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;,&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt;组成的三元组定义为一个三角形。&lt;br /&gt;
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We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
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We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
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我们也可以将顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量定义为&amp;lt;math&amp;gt;\delta(i)&amp;lt;/math&amp;gt;，并且由于每个三角形都被计数了三次，我们可以将图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中三角形的个数表达为&amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
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Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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假设三元闭包性质成立，则一个三元组仅需要两条强联系便可形成三角形。 因此，在三元闭包性质成立的前提下，理论上顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量为&amp;lt;math&amp;gt;\tau(i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;，假设&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;。我们可以表示&amp;lt;math&amp;gt;\tau(G) = \frac{1}{3} \sum_{i\in V} \ \tau(i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
&lt;br /&gt;
Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the [[clustering coefficient]] &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the [[clustering coefficient]] &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
&lt;br /&gt;
Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the clustering coefficient &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the clustering coefficient &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
&lt;br /&gt;
现在，对于具有&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;的顶点，顶点&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的聚集系数是其拥有的三角形的占比，即&amp;lt;math&amp;gt;\frac{\delta(i)}{\tau(i)}&amp;lt;/math&amp;gt;。 因此，图&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;的聚集系数&amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt;由&amp;lt;math&amp;gt; C(G)=\frac {1}{N_2} \sum_{i \in V,d_i \ge 2}c(i)&amp;lt;/math&amp;gt;给出，其中&amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt;是度至少为2的顶点数量。&lt;br /&gt;
&lt;br /&gt;
==Transitivity==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;传递性 Transitivity&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
&lt;br /&gt;
Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
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测量'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''是否出现的另一方法是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;传递性&amp;lt;/font&amp;gt;'''，定义为&amp;lt;math&amp;gt;T(G)= \frac{3\delta(G)}{\tau(G)}&amp;lt;/math&amp;gt;。&lt;br /&gt;
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==Causes and effects==&lt;br /&gt;
==形成及其影响==&lt;br /&gt;
&lt;br /&gt;
In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&lt;br /&gt;
&lt;br /&gt;
在一个信任网络中，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''性质的出现往往是由于'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;传递性&amp;lt;/font&amp;gt;'''。如果'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''A信任'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''B，并且'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''B信任'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''C，则'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''A将具有信任'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''C的基础。在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;社会网络&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强三元闭包 Strong Triadic Closure&amp;lt;/font&amp;gt;'''性质的出现往往是由于'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''A与'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''C拥有共同邻居'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''B，因为他们相遇的机会将会增加进而至少产生一条'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;弱联系 Weak Tie&amp;lt;/font&amp;gt;'''。此外，由于两段分离的关系所带来的潜在压力，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''B也具有将'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''A和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''C聚在一起的动机。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
&lt;br /&gt;
Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
&lt;br /&gt;
遵循此原理的网络将高度互连且具有极高的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;聚集系数&amp;lt;/font&amp;gt;'''。 与此相反，不遵循该原理的网络的连通性则较差，且一旦包含负面关系，网络则可能会变得较不稳定。&lt;br /&gt;
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&lt;br /&gt;
Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''是分析网络如何随时间演变的一个良好模型。 '''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;简单图论 Simple Graph Theory&amp;lt;/font&amp;gt;'''倾向于在某个时点分析网络，而应用'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''原理则可以预测网络中联系的形成，以及网络连通性的发展。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
In [[social networks]], triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
&lt;br /&gt;
In social networks, triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
&lt;br /&gt;
在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;社会网络&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''将促进合作行为，但是当通过从现有联系中推荐人时，合作者的平均全球比例要小于个人从总体人口中随机选择新联系时的比例。 对此的两个可能的影响是结构和信息结构。 结构构造来自于倾向于高度可聚性的倾向。 信息结构来自这样一个假设：与随机的陌生人不同，一个人对朋友的朋友有所了解。&lt;br /&gt;
&lt;br /&gt;
==Strong Triadic Closure Property and local bridges==&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强三元闭包性 Strong Triadic Closure Property &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;本地网桥 Local Bridges &amp;lt;/font&amp;gt;'''&amp;lt;br&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A [[local bridge]] occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
&lt;br /&gt;
Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A local bridge occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
&lt;br /&gt;
强三元闭包性是，如果一个节点与两个邻居有牢固的联系，则这些邻居之间必须至少有一条弱联系。 另一方面，当节点充当两个其他未连接的相邻节点之间的网守时，则发生本地网桥。 在遵循“强三元闭合性”的网络中，本地网桥中涉及的节点之间的联系之一必须是弱联系。&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Proof by contradiction==&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;矛盾证明 Proof By Contradiction &amp;lt;/font&amp;gt;'''&amp;lt;br&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&lt;br /&gt;
&lt;br /&gt;
假设节点B是节点A和C之间的本地桥梁，以使所涉及的节点之间没有弱联系。 因此，B与A和C都具有牢固的联系。根据“强三元闭包性”的定义，节点A和C之间将形成弱联系。但是，这与B是本地网守的事实相矛盾。 因此，本地网桥中涉及的至少一个节点需要是弱连接，以防止三元闭包的发生。&lt;br /&gt;
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==References==&lt;br /&gt;
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{{Reflist}}&lt;br /&gt;
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{{Social networking}}&lt;br /&gt;
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{{DEFAULTSORT:Triadic Closure}}&lt;br /&gt;
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[[Category:Social systems]]&lt;br /&gt;
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Category:Social systems&lt;br /&gt;
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类别: 社会系统&lt;br /&gt;
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[[Category:Sociological terminology]]&lt;br /&gt;
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Category:Sociological terminology&lt;br /&gt;
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类别: 社会学术语&lt;br /&gt;
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&amp;lt;noinclude&amp;gt;&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Triadic closure]]. Its edit history can be viewed at [[三元闭包/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
	</entry>
	<entry>
		<id>https://wiki.swarma.org/index.php?title=%E4%B8%89%E5%85%83%E9%97%AD%E5%8C%85&amp;diff=16552</id>
		<title>三元闭包</title>
		<link rel="alternate" type="text/html" href="https://wiki.swarma.org/index.php?title=%E4%B8%89%E5%85%83%E9%97%AD%E5%8C%85&amp;diff=16552"/>
		<updated>2020-10-22T11:30:34Z</updated>

		<summary type="html">&lt;p&gt;Alienxj：/* 聚集系数 */&lt;/p&gt;
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&lt;div&gt;本词条由信白初步翻译&lt;br /&gt;
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'''Triadic closure''' is a concept in [[social network]] theory, first suggested by [[Germany|German]] [[sociology|sociologist]] [[Georg Simmel]] in his 1908 book ''Soziologie'' [''Sociology: Investigations on the Forms of Sociation''].&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C.&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Triadic closure is a concept in social network theory, first suggested by German sociologist Georg Simmel in his 1908 book Soziologie [Sociology: Investigations on the Forms of Sociation]. Triadic closure is the property among three nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is only a strong tie between B-C. This property is too extreme to hold true across very large, complex networks, but it is a useful simplification of reality that can be used to understand and predict networks.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包 Triadic Closure &amp;lt;/font&amp;gt;'''是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;社会网络 Social Network&amp;lt;/font&amp;gt;'''理论中的一个概念，最早由德国社会学家格奥尔格·西梅尔 Georg Simmel在其1908年的著作《社会学：社会形式的调查》 Sociology: Investigations on the Forms of Sociation中提出。&amp;lt;ref&amp;gt;[https://www.nytimes.com/2007/12/17/style/17facebook.html?pagewanted=print Georg Simmel], originator of the concept: &amp;quot;Facebook&amp;quot; article at [[the New York Times]] website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt;三元闭包指的是由A，B，C三个'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点 Node&amp;lt;/font&amp;gt;'''所组成的三元组的一种性质，即如果A-B和A-C之间存在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强联系 Strong Tie &amp;lt;/font&amp;gt;'''，则B-C之间也仅存在强联系。&amp;lt;ref&amp;gt;[https://serendipstudio.org/complexity/course/emergence06/bookreviews/kmaffei.html Working concept] of triadic closure: book review of [[Duncan Watts]]' &amp;quot;[[Six Degrees: The Science of a Connected Age]]&amp;quot; at the ''Serendip'' ([[Bryn Mawr College]]) website. Retrieved on December 21, 2007.&amp;lt;/ref&amp;gt; 这一性质过于极端，以至于它难以在规模较大、结构复杂的网络中被满足，然而在理解网络与网络预测等方面，它却是一种十分有用的对现实的简化。&amp;lt;ref name=Easley&amp;gt;Easley, D, &amp;amp; Kleinberg, J. (2010). Networks, crowds, and markets: reasoning about a highly connected world. Cornell, NY: Cambridge Univ Pr.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==History==&lt;br /&gt;
Triadic closure was made popular by [[Mark Granovetter]] in his 1973 article ''The Strength of Weak Ties''.&amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; There he synthesized the theory of [[cognitive balance]] first introduced by [[Fritz Heider]] in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
&lt;br /&gt;
Triadic closure was made popular by Mark Granovetter in his 1973 article The Strength of Weak Ties. There he synthesized the theory of cognitive balance first introduced by Fritz Heider in 1946 with a Simmelian understanding of social networks. In general terms, cognitive balance refers to the propensity of two individuals to want to feel the same way about an object. If the triad of three individuals is not closed, then the person connected to both of the individuals will want to close this triad in order to achieve closure in the relationship network.&lt;br /&gt;
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==历史==&lt;br /&gt;
马克·格兰诺维特 Mark Granovetter在1973年发表的《弱链接的力量》 The Strength of Weak Ties一文使得三元闭包性质变得流行。 &amp;lt;ref&amp;gt;Granovetter, M. (1973). &amp;quot;[http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf The Strength of Weak Ties] {{webarchive|url=https://web.archive.org/web/20080216103216/http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf |date=2008-02-16 }}&amp;quot;, American Journal of Sociology, Vol. 78, Issue 6, May 1360-80.&amp;lt;/ref&amp;gt; 在这一文章中，他综合了弗里茨·海德 Fritz Heider于1946年提出的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;认知平衡 Cognitive Balance &amp;lt;/font&amp;gt;'''理论以及Georg Simmel对社会网络的理解。 一般而言，认知平衡是指两个个体对同一事物具有产生相同感觉的倾向。 如果三个个体所组成的三元组没有闭合，那么与同一个体联系的其余两个个体均将想要闭合这一三元组，进而在关系网络中形成闭包。&lt;br /&gt;
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==Measurements==&lt;br /&gt;
{{Unreferenced section|date=September 2009}}&lt;br /&gt;
The two most common measures of triadic closure for a graph are (in no particular order) the [[clustering coefficient]] and transitivity for that graph.&lt;br /&gt;
&lt;br /&gt;
The two most common measures of triadic closure for a graph are (in no particular order) the clustering coefficient and transitivity for that graph.&lt;br /&gt;
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==测量==&lt;br /&gt;
最常见的测量一张'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;图 Graph&amp;lt;/font&amp;gt;'''的三元闭包性质的两种方法（排名不分先后）是采用该图的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;聚集系数 Clustering Coefficient &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;传递性 Transitivity&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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==Clustering coefficient==&lt;br /&gt;
==聚集系数==&lt;br /&gt;
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One measure for the presence of triadic closure is [[clustering coefficient]], as follows:&lt;br /&gt;
&lt;br /&gt;
One measure for the presence of triadic closure is clustering coefficient, as follows:&lt;br /&gt;
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测量三元闭包是否出现的方法之一是聚集系数，如下所示：&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the [[degree (graph theory)|degree]] of vertex i.&lt;br /&gt;
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Let &amp;lt;math&amp;gt;G = (V,E)&amp;lt;/math&amp;gt; be an undirected simple graph (i.e., a graph having no self-loops or multiple edges) with V the set of vertices and E the set of edges. Also, let &amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt; denote the number of vertices and edges in G, respectively, and let &amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; be the degree of vertex i.&lt;br /&gt;
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令&amp;lt;math&amp;gt;G =(V，E)&amp;lt;/math&amp;gt;是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;无向简单图 Undirected Simple Graph&amp;lt;/font&amp;gt;'''（即，没有'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;自环 Self-loops&amp;lt;/font&amp;gt;'''或'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;多重边 Multiple Edges&amp;lt;/font&amp;gt;'''的图），其中&amp;lt;math&amp;gt;V&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点 Vertice&amp;lt;/font&amp;gt;'''集，&amp;lt;math&amp;gt;E&amp;lt;/math&amp;gt;为'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;边 Edge&amp;lt;/font&amp;gt;'''集。 另外，令&amp;lt;math&amp;gt;N = |V|&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;M = |E|&amp;lt;/math&amp;gt;分别表示'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;图&amp;lt;/font&amp;gt;'''&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点&amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;边&amp;lt;/font&amp;gt;'''的数量，并令&amp;lt;math&amp;gt;d_i&amp;lt;/math&amp;gt; 表示'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点&amp;lt;/font&amp;gt;'''&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;度 Degree&amp;lt;/font&amp;gt;'''。&lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
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We can define a triangle among the triple of vertices &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;, and &amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt; to be a set with the following three edges: {(i,j), (j,k), (i,k)}. &lt;br /&gt;
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我们可以通过'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;边&amp;lt;/font&amp;gt;'''集&amp;lt;math&amp;gt;((i,j),(j,k),(i,k))&amp;lt;/math&amp;gt;，将由'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点&amp;lt;/font&amp;gt;'''&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;,&amp;lt;math&amp;gt;j&amp;lt;/math&amp;gt;和&amp;lt;math&amp;gt;k&amp;lt;/math&amp;gt;组成的三元组定义为一个三角形。&lt;br /&gt;
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We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
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We can also define the number of triangles that vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is involved in as &amp;lt;math&amp;gt;\delta (i)&amp;lt;/math&amp;gt; and, as each triangle is counted three times, we can express the number of triangles in G as &amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;. &lt;br /&gt;
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我们也可以将'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点&amp;lt;/font&amp;gt;'''&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量定义为&amp;lt;math&amp;gt;\delta(i)&amp;lt;/math&amp;gt;，并且由于每个三角形都被计数了三次，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;图&amp;lt;/font&amp;gt;'''&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;中三角形的个数为&amp;lt;math&amp;gt;\delta (G) = \frac{1}{3} \sum_{i\in V} \ \delta (i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
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Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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Assuming that triadic closure holds, only two strong edges are required for a triple to form. Thus, the number of theoretical triples that should be present under the triadic closure hypothesis for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;\tau (i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;, assuming &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;. We can express &amp;lt;math&amp;gt;\tau (G) = \frac{1}{3} \sum_{i\in V} \ \tau (i)&amp;lt;/math&amp;gt;.&lt;br /&gt;
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假设'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''性质成立，则一个三元组仅需要两条'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强联系&amp;lt;/font&amp;gt;'''便可形成三角形。 因此，在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''性质成立的前提下，理论上'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点&amp;lt;/font&amp;gt;'''&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;所涉及的三角形的数量为&amp;lt;math&amp;gt;\tau(i) = \binom{d_i}{2}&amp;lt;/math&amp;gt;， 假设&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;。 我们可以表示&amp;lt;math&amp;gt;\tau(G) = \frac{1}{3} \sum_{i\in V} \ \tau(i)&amp;lt;/math&amp;gt;。&lt;br /&gt;
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Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the [[clustering coefficient]] &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the [[clustering coefficient]] &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
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Now, for a vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; with &amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;, the clustering coefficient &amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; of vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; is the fraction of triples for vertex &amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt; that are closed, and can be measured as &amp;lt;math&amp;gt;\frac{\delta (i)}{\tau (i)}&amp;lt;/math&amp;gt;. Thus, the clustering coefficient &amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt; of graph &amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt; is given by &amp;lt;math&amp;gt;C(G) = \frac {1}{N_2} \sum_{i \in V, d_i \ge 2} c(i)&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt; is the number of nodes with degree at least 2.&lt;br /&gt;
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现在，对于具有&amp;lt;math&amp;gt;d_i \ge 2&amp;lt;/math&amp;gt;的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点&amp;lt;/font&amp;gt;'''&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点&amp;lt;/font&amp;gt;'''&amp;lt;math&amp;gt;i&amp;lt;/math&amp;gt;的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;聚集系数&amp;lt;/font&amp;gt;'''&amp;lt;math&amp;gt;c(i)&amp;lt;/math&amp;gt; 是其拥有的三角形的占比，即&amp;lt;math&amp;gt;\frac{\delta(i)}{\tau(i)}&amp;lt;/math&amp;gt;。 因此，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;图&amp;lt;/font&amp;gt;'''&amp;lt;math&amp;gt;G&amp;lt;/math&amp;gt;的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;聚集系数&amp;lt;/font&amp;gt;'''&amp;lt;math&amp;gt;C(G)&amp;lt;/math&amp;gt;由&amp;lt;math&amp;gt; C(G)=\frac {1}{N_2} \sum_{i \in V,d_i \ge 2}c(i)&amp;lt;/math&amp;gt;给出，其中&amp;lt;math&amp;gt;N_2&amp;lt;/math&amp;gt;是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;度&amp;lt;/font&amp;gt;'''至少为2的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;顶点&amp;lt;/font&amp;gt;'''数量。&lt;br /&gt;
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==Transitivity==&lt;br /&gt;
=='''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;传递性 Transitivity&amp;lt;/font&amp;gt;'''==&lt;br /&gt;
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Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
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Another measure for the presence of triadic closure is transitivity, defined as &amp;lt;math&amp;gt;T(G) = \frac{3\delta (G)}{\tau (G)}&amp;lt;/math&amp;gt;.&lt;br /&gt;
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测量'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''是否出现的另一方法是'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;传递性&amp;lt;/font&amp;gt;'''，定义为&amp;lt;math&amp;gt;T(G)= \frac{3\delta(G)}{\tau(G)}&amp;lt;/math&amp;gt;。&lt;br /&gt;
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==Causes and effects==&lt;br /&gt;
==形成及其影响==&lt;br /&gt;
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In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
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In a trust network, triadic closure is likely to develop due to the transitive property. If a node A trusts node B, and node B trusts node C, node A will have the basis to trust node C. In a social network, strong triadic closure occurs because there is increased opportunity for nodes A and C with common neighbor B to meet and therefore create at least weak ties. Node B also has the incentive to bring A and C together to decrease the latent stress in two separate relationships.&lt;br /&gt;
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在一个信任网络中，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''性质的出现往往是由于'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;传递性&amp;lt;/font&amp;gt;'''。如果'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''A信任'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''B，并且'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''B信任'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''C，则'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''A将具有信任'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''C的基础。在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;社会网络&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强三元闭包 Strong Triadic Closure&amp;lt;/font&amp;gt;'''性质的出现往往是由于'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''A与'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''C拥有共同邻居'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''B，因为他们相遇的机会将会增加进而至少产生一条'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;弱联系 Weak Tie&amp;lt;/font&amp;gt;'''。此外，由于两段分离的关系所带来的潜在压力，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''B也具有将'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''A和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;节点&amp;lt;/font&amp;gt;'''C聚在一起的动机。&lt;br /&gt;
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Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
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Networks that stay true to this principle become highly interconnected and have very high clustering coefficients. However, networks that do not follow this principle turn out to be poorly connected and may suffer from instability once negative relations are included.&lt;br /&gt;
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遵循此原理的网络将高度互连且具有极高的'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;聚集系数&amp;lt;/font&amp;gt;'''。 与此相反，不遵循该原理的网络的连通性则较差，且一旦包含负面关系，网络则可能会变得较不稳定。&lt;br /&gt;
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Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
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Triadic closure is a good model for how networks will evolve over time. While simple graph theory tends to analyze networks at one point in time, applying the triadic closure principle can predict the development of ties within a network and show the progression of connectivity.&lt;br /&gt;
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'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''是分析网络如何随时间演变的一个良好模型。 '''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;简单图论 Simple Graph Theory&amp;lt;/font&amp;gt;'''倾向于在某个时点分析网络，而应用'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''原理则可以预测网络中联系的形成，以及网络连通性的发展。&lt;br /&gt;
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In [[social networks]], triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
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In social networks, triadic closure facilitates cooperative behavior, but when new connections are made via referrals from existing connections the average global fraction of cooperators is less than when individuals choose new connections randomly from the population at large. Two possible effects for this are by the structural and informational construction. The structural construction arises from the propensity toward high clusterability. The informational construction comes from the assumption that an individual knows something about a friend's friend, as opposed to a random stranger.&lt;br /&gt;
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在'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;社会网络&amp;lt;/font&amp;gt;'''中，'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;三元闭包&amp;lt;/font&amp;gt;'''将促进合作行为，但是当通过从现有联系中推荐人时，合作者的平均全球比例要小于个人从总体人口中随机选择新联系时的比例。 对此的两个可能的影响是结构和信息结构。 结构构造来自于倾向于高度可聚性的倾向。 信息结构来自这样一个假设：与随机的陌生人不同，一个人对朋友的朋友有所了解。&lt;br /&gt;
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==Strong Triadic Closure Property and local bridges==&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;强三元闭包性 Strong Triadic Closure Property &amp;lt;/font&amp;gt;'''和'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;本地网桥 Local Bridges &amp;lt;/font&amp;gt;'''&amp;lt;br&amp;gt;&lt;br /&gt;
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Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A [[local bridge]] occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
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Strong Triadic Closure Property is that if a node has strong ties to two neighbors, then these neighbors must have at least a weak tie between them. A local bridge occurs, on the other hand, when a node is acting as a gatekeeper between two neighboring nodes who are not otherwise connected. In a network that follows the Strong Triadic Closure Property, one of the ties between nodes involved in a local bridge needs to be a weak tie.&lt;br /&gt;
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强三元闭包性是，如果一个节点与两个邻居有牢固的联系，则这些邻居之间必须至少有一条弱联系。 另一方面，当节点充当两个其他未连接的相邻节点之间的网守时，则发生本地网桥。 在遵循“强三元闭合性”的网络中，本地网桥中涉及的节点之间的联系之一必须是弱联系。&lt;br /&gt;
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==Proof by contradiction==&lt;br /&gt;
'''&amp;lt;font color=&amp;quot;#FF8000&amp;quot;&amp;gt;矛盾证明 Proof By Contradiction &amp;lt;/font&amp;gt;'''&amp;lt;br&amp;gt;&lt;br /&gt;
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Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&amp;lt;ref name=Easley/&amp;gt;&lt;br /&gt;
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Let node B be a local bridge between nodes A and C such that there is no weak tie between the nodes involved. Therefore, B has a strong tie to both A and C. By the definition of Strong Triadic Closure, a weak tie would develop between nodes A and C. However, this contradicts the fact that B is a local gatekeeper. Thus at least one of the nodes involved in a local bridge needs to be a weak tie to prevent triadic closure from occurring.&lt;br /&gt;
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假设节点B是节点A和C之间的本地桥梁，以使所涉及的节点之间没有弱联系。 因此，B与A和C都具有牢固的联系。根据“强三元闭包性”的定义，节点A和C之间将形成弱联系。但是，这与B是本地网守的事实相矛盾。 因此，本地网桥中涉及的至少一个节点需要是弱连接，以防止三元闭包的发生。&lt;br /&gt;
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==References==&lt;br /&gt;
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&amp;lt;small&amp;gt;This page was moved from [[wikipedia:en:Triadic closure]]. Its edit history can be viewed at [[三元闭包/edithistory]]&amp;lt;/small&amp;gt;&amp;lt;/noinclude&amp;gt;&lt;br /&gt;
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[[Category:待整理页面]]&lt;/div&gt;</summary>
		<author><name>Alienxj</name></author>
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