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此词条暂由彩云小译翻译,未经人工整理和审校,带来阅读不便,请见谅。
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此词条暂由彩云小译翻译,翻译字数共604,未经人工整理和审校,带来阅读不便,请见谅。
    
[[File:CLD positive ANI.gif|thumb|264px|Example of positive [[reinforcing loop]]: ''Bank balance'' and ''Earned interest'']]
 
[[File:CLD positive ANI.gif|thumb|264px|Example of positive [[reinforcing loop]]: ''Bank balance'' and ''Earned interest'']]
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A causal loop diagram (CLD) is a causal diagram that aids in visualizing how different variables in a system are interrelated. The diagram consists of a set of nodes and edges. Nodes represent the variables and edges are the links that represent a connection or a relation between the two variables. A link marked positive indicates a positive relation and a link marked negative indicates a negative relation. A positive causal link means the two nodes change in the same direction, i.e. if the node in which the link starts decreases, the other node also decreases. Similarly, if the node in which the link starts increases, the other node increases as well. A negative causal link means the two nodes change in opposite directions, i.e. if the node in which the link starts increases, the other node decreases and vice versa. <br />
 
A causal loop diagram (CLD) is a causal diagram that aids in visualizing how different variables in a system are interrelated. The diagram consists of a set of nodes and edges. Nodes represent the variables and edges are the links that represent a connection or a relation between the two variables. A link marked positive indicates a positive relation and a link marked negative indicates a negative relation. A positive causal link means the two nodes change in the same direction, i.e. if the node in which the link starts decreases, the other node also decreases. Similarly, if the node in which the link starts increases, the other node increases as well. A negative causal link means the two nodes change in opposite directions, i.e. if the node in which the link starts increases, the other node decreases and vice versa. <br />
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环路图图是一种因果关系图,有助于可视化地显示一个系统中不同的变量是如何相互关联的。该图由一组节点和边组成。节点表示变量,边是表示两个变量之间的联系或关系的链接。标记为肯定的链接表示肯定关系,标记为否定的链接表示否定关系。一个积极的因果关系意味着两个节点朝着同一个方向改变,即。如果链接开始的节点减少,另一个节点也减少。类似地,如果链接开始的节点增加,其他节点也会增加。负的因果关系是指两个节点朝相反的方向变化,即。如果链接开始的节点增加,另一个节点减少,反之亦然。Br /
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环路图图是一种因果关系图,有助于可视化地显示一个系统中不同的变量是如何相互关联的。该图由一组节点和边组成。节点表示变量,边是表示两个变量之间的联系或关系的链接。标记为肯定的链接表示肯定关系,标记为否定的链接表示否定关系。一个积极的因果关系意味着两个节点朝着同一个方向改变,即。如果链接开始的节点减少,另一个节点也减少。类似地,如果链接开始的节点增加,其他节点也会增加。负的因果关系是指两个节点朝相反的方向变化,即。如果链接开始的节点增加,另一个节点减少,反之亦然。< br/>
    
Closed cycles in the diagram are very important features of the CLDs. A closed cycle is either defined as a '''reinforcing''' or '''balancing''' [[feedback]] loop. A reinforcing loop is a cycle in which the effect of a variation in any variable propagates through the loop and returns to the variable reinforcing the initial deviation i.e. if a variable increases in a reinforcing loop the effect through the cycle will return an increase to the same variable and vice versa. A balancing loop is the cycle in which the effect of a variation in any variable propagates through the loop and returns to the variable a deviation opposite to the initial one i.e. if a variable increases in a balancing loop the effect through the cycle will return a decrease to the same variable and vice versa.
 
Closed cycles in the diagram are very important features of the CLDs. A closed cycle is either defined as a '''reinforcing''' or '''balancing''' [[feedback]] loop. A reinforcing loop is a cycle in which the effect of a variation in any variable propagates through the loop and returns to the variable reinforcing the initial deviation i.e. if a variable increases in a reinforcing loop the effect through the cycle will return an increase to the same variable and vice versa. A balancing loop is the cycle in which the effect of a variation in any variable propagates through the loop and returns to the variable a deviation opposite to the initial one i.e. if a variable increases in a balancing loop the effect through the cycle will return a decrease to the same variable and vice versa.
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John D.Sterman, ''Business Dynamics: Systems Thinking and Modeling for a Complex World.'' McGraw Hill/Irwin, 2000. {{ISBN|9780072389159}}
 
John D.Sterman, ''Business Dynamics: Systems Thinking and Modeling for a Complex World.'' McGraw Hill/Irwin, 2000. {{ISBN|9780072389159}}
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John D.Sterman, Business Dynamics: Systems Thinking and Modeling for a Complex World. McGraw Hill/Irwin, 2000.
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约翰 · d · 斯特曼,《商业动力学: 复杂世界的系统思考与建模》。麦格劳 · 希尔 / 欧文,2000年。
      
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/ 参考
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==History==
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The use of nodes and arrows to construct directed graph models of cause and effect dates back to the invention of  path analysis by Sewall Wright in 1918, long before System Dynamics. Due to the limitations of genetic data, however, these early causal graphs contained no loops — they were directed acyclic graphs. The first formal use of Causal Loop Diagrams was explained by Dr. Dennis Meadows at a conference for educators (Systems Thinking & Dynamic Modeling Conference for K-12 Education in New Hampshire sponsored by Creative Learning Exchange ).
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==History==
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使用节点和箭头来构建因果关系的有向图模型可以追溯到1918年 Sewall Wright 发明的路径分析,远在系统动力学之前。然而,由于遗传数据的局限性,这些早期因果图不包含环路ーー它们是有向无环图。丹尼斯 · 梅多斯博士在新罕布什尔州的一次教育工作者会议(由创造性学习交流组织主办的 K-12教育系统思考与动态建模会议)上解释了因果循环图的第一次正式使用。
    
{{Main article|System Dynamics}}
 
{{Main article|System Dynamics}}
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The use of nodes and arrows to construct [[directed graph]] models of cause and effect dates back to the invention of  [[Path analysis (statistics)|path analysis]] by [[Sewall Wright]] in 1918, long before System Dynamics. Due to the limitations of genetic data, however, these early causal graphs contained no loops — they were [[directed acyclic graph]]s. The first formal use of Causal Loop Diagrams was explained by Dr. Dennis Meadows at a conference for educators (Systems Thinking & Dynamic Modeling Conference for K-12 Education in New Hampshire sponsored by Creative Learning Exchange <ref>http://www.clexchange.org/</ref>).
 
The use of nodes and arrows to construct [[directed graph]] models of cause and effect dates back to the invention of  [[Path analysis (statistics)|path analysis]] by [[Sewall Wright]] in 1918, long before System Dynamics. Due to the limitations of genetic data, however, these early causal graphs contained no loops — they were [[directed acyclic graph]]s. The first formal use of Causal Loop Diagrams was explained by Dr. Dennis Meadows at a conference for educators (Systems Thinking & Dynamic Modeling Conference for K-12 Education in New Hampshire sponsored by Creative Learning Exchange <ref>http://www.clexchange.org/</ref>).
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The use of nodes and arrows to construct directed graph models of cause and effect dates back to the invention of  path analysis by Sewall Wright in 1918, long before System Dynamics. Due to the limitations of genetic data, however, these early causal graphs contained no loops — they were directed acyclic graphs. The first formal use of Causal Loop Diagrams was explained by Dr. Dennis Meadows at a conference for educators (Systems Thinking & Dynamic Modeling Conference for K-12 Education in New Hampshire sponsored by Creative Learning Exchange ).
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Meadows explained that when he and others were working on the World3 model (circa 1970–72), they realized they would not be able to use the computer output to explain how the feedback loops worked in their model when presenting their results to others. They decided to show feedback loops (without the stocks, flows and every variable), using arrows connecting the names of major model components in the feedback loops. This may have been the first formal use of Causal Loop Diagrams.
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使用节点和箭头来构建因果关系的有向图模型可以追溯到1918年 Sewall Wright 发明的路径分析,远在系统动力学之前。然而,由于遗传数据的局限性,这些早期因果图不包含环路ーー它们是有向无环图。丹尼斯 · 梅多斯博士在新罕布什尔州的一次教育工作者会议(由创造性学习交流组织主办的 K-12教育系统思考与动态建模会议)上解释了因果循环图的第一次正式使用。
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Meadows 解释说,当他和其他人在研究 World3模型(大约在1970-72年)时,他们意识到他们不能用计算机输出来解释他们的模型中的反馈回路在向其他人展示结果时是如何工作的。他们决定显示反馈回路(没有存量、流量和每个变量) ,使用箭头连接反馈回路中主要模型组件的名称。这可能是因果循环图的第一次正式使用。
          
Meadows explained that when he and others were working on the [[World3]] model (circa 1970–72), they realized they would not be able to use the computer output to explain how the feedback loops worked in their model when presenting their results to others. They decided to show feedback loops (without the stocks, flows and every variable), using arrows connecting the names of major model components in the feedback loops. This may have been the first formal use of Causal Loop Diagrams.<ref>Anecdote by Richard Turnock attending informal discussion where Dennis Meadows explained origin of CLD</ref>
 
Meadows explained that when he and others were working on the [[World3]] model (circa 1970–72), they realized they would not be able to use the computer output to explain how the feedback loops worked in their model when presenting their results to others. They decided to show feedback loops (without the stocks, flows and every variable), using arrows connecting the names of major model components in the feedback loops. This may have been the first formal use of Causal Loop Diagrams.<ref>Anecdote by Richard Turnock attending informal discussion where Dennis Meadows explained origin of CLD</ref>
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Meadows explained that when he and others were working on the World3 model (circa 1970–72), they realized they would not be able to use the computer output to explain how the feedback loops worked in their model when presenting their results to others. They decided to show feedback loops (without the stocks, flows and every variable), using arrows connecting the names of major model components in the feedback loops. This may have been the first formal use of Causal Loop Diagrams.
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Meadows 解释说,当他和其他人在研究 World3模型(大约在1970-72年)时,他们意识到他们不能用计算机输出来解释他们的模型中的反馈回路在向其他人展示结果时是如何工作的。他们决定显示反馈回路(没有存量、流量和每个变量) ,使用箭头连接反馈回路中主要模型组件的名称。这可能是因果循环图的第一次正式使用。
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frame
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框架
    
===Example===
 
===Example===
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[[File:CLD links ANI.gif|centre|Dynamic causal loop diagram: positive and negative links|frame]]
 
[[File:CLD links ANI.gif|centre|Dynamic causal loop diagram: positive and negative links|frame]]
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frame
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框架
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To determine if a causal loop is reinforcing or balancing, one can start with an assumption, e.g. "Node 1 increases" and follow the loop around. The loop is:
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为了确定一个因果循环是在加强还是在平衡,我们可以从一个假设开始,例如:。“节点1增加”并循环。这个循环是:
    
==Reinforcing and balancing loops==
 
==Reinforcing and balancing loops==
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To determine if a causal loop is reinforcing or balancing, one can start with an assumption, e.g. "Node 1 increases" and follow the loop around. The loop is:
 
To determine if a causal loop is reinforcing or balancing, one can start with an assumption, e.g. "Node 1 increases" and follow the loop around. The loop is:
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To determine if a causal loop is reinforcing or balancing, one can start with an assumption, e.g. "Node 1 increases" and follow the loop around. The loop is:
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* '''reinforcing''' if, after going around the loop, one ends up with the same result as the initial assumption.
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为了确定一个因果循环是在加强还是在平衡,我们可以从一个假设开始,例如:。“节点1增加”并跟随循环。回路是:
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Or to put it in other words:
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* '''reinforcing''' if, after going around the loop, one ends up with the same result as the initial assumption.
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或者换句话说:
    
* '''balancing''' if the result contradicts the initial assumption.
 
* '''balancing''' if the result contradicts the initial assumption.
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Or to put it in other words:
 
Or to put it in other words:
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Or to put it in other words:
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* [[reinforcing loop]]s have an even number of negative links (zero also is even, see example below)
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或者换句话说:
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* [[balancing loop]]s have an odd number of negative links.
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* [[reinforcing loop]]s have an even number of negative links (zero also is even, see example below)
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Identifying reinforcing and balancing loops is an important step for identifying Reference Behaviour Patterns, i.e. possible dynamic behaviours of the system.
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* [[balancing loop]]s have an odd number of negative links.
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识别加强和平衡循环是识别参照行为模式的一个重要步骤,即。系统可能的动态行为。
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Identifying reinforcing and balancing loops is an important step for identifying ''Reference Behaviour Patterns'', i.e. possible dynamic behaviours of the system.
 
Identifying reinforcing and balancing loops is an important step for identifying ''Reference Behaviour Patterns'', i.e. possible dynamic behaviours of the system.
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Identifying reinforcing and balancing loops is an important step for identifying Reference Behaviour Patterns, i.e. possible dynamic behaviours of the system.
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* Reinforcing loops are associated with exponential increases/decreases.
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识别加强和平衡循环是识别参照行为模式的一个重要步骤,即。系统可能的动态行为。
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If the system has delays (often denoted by drawing a short line across the causal link), the system might fluctuate.
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* Reinforcing loops are associated with exponential increases/decreases.
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如果系统有延迟(通常表示在因果关系之间画一条短线) ,系统可能会发生波动。
    
* Balancing loops are associated with reaching a plateau.
 
* Balancing loops are associated with reaching a plateau.
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If the system has delays (often denoted by drawing a short line across the causal link), the system might fluctuate.
 
If the system has delays (often denoted by drawing a short line across the causal link), the system might fluctuate.
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If the system has delays (often denoted by drawing a short line across the causal link), the system might fluctuate.
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如果系统有延迟(通常表示在因果关系之间画一条短线) ,系统可能会发生波动。
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frame
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框架
    
===Example===
 
===Example===
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[[File:Causal_Loop_Diagram_of_a_Model.png|centre|Causal loop diagram of a model examining the growth or decline of a life insurance company|frame]]
 
[[File:Causal_Loop_Diagram_of_a_Model.png|centre|Causal loop diagram of a model examining the growth or decline of a life insurance company|frame]]
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frame
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框架
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{{DEFAULTSORT:Causal Loop Diagram}}
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[[Category:Causal diagrams]]
      
Category:Causal diagrams
 
Category:Causal diagrams
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类别: 因果图表
 
类别: 因果图表
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[[Category:Diagrams]]
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{{DEFAULTSORT:Causal Loop Diagram}}
    
Category:Diagrams
 
Category:Diagrams
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类别: 图表
 
类别: 图表
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[[Category:Causality]]
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[[Category:Causal diagrams]]
    
Category:Causality
 
Category:Causality
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