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| f_c &=1-\frac{1}{\kappa-1}\\ | | f_c &=1-\frac{1}{\kappa-1}\\ |
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− | kappa &=\frac{\langle k^2\rangle}{\langle k \rangle}=\left|\frac{2-\gamma}{3-\gamma}\right|A \\ | + | f_c &=1-\frac{1}{\kappa-1}\\ |
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| + | 1-frac {1}{ kappa-1} |
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| + | \kappa &=\frac{\langle k^2\rangle}{\langle k \rangle}=\left|\frac{2-\gamma}{3-\gamma}\right|A \\ |
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| + | \kappa &=\frac{\langle k^2\rangle}{\langle k \rangle}=\left|\frac{2-\gamma}{3-\gamma}\right|A \\ |
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| + | Kappa & = frac { langle k ^ 2 rangle }{ langle k rangle } = left | frac {2-gamma }{3-gamma } right | a |
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| + | A &=K_{min},~\gamma > 3 \\ |
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| A &=K_{min},~\gamma > 3 \\ | | A &=K_{min},~\gamma > 3 \\ |
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| + | A & = k { min } ,~ gamma > 3 |
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| A &=K_{max}^{3-\gamma}K_{min}^{\gamma-2},~3 > \gamma > 2 \\ | | A &=K_{max}^{3-\gamma}K_{min}^{\gamma-2},~3 > \gamma > 2 \\ |
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| + | A &=K_{max}^{3-\gamma}K_{min}^{\gamma-2},~3 > \gamma > 2 \\ |
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| + | A & = k _ { max } ^ {3-gamma } k _ { min } ^ { gamma-2} ,~ 3 > gamma > 2 |
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| A &=K_{max},~2 > \gamma > 1 \\ | | A &=K_{max},~2 > \gamma > 1 \\ |
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| + | A &=K_{max},~2 > \gamma > 1 \\ |
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| + | A & = k { max } ,~ 2 > γ > 1 |
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| + | &where~K_{max}=K_{min}N^{\frac{1}{\gamma - 1}} |
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| &where~K_{max}=K_{min}N^{\frac{1}{\gamma - 1}} | | &where~K_{max}=K_{min}N^{\frac{1}{\gamma - 1}} |
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| </math> | | </math> |
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| For gamma greater than 3, the critical threshold only depends on gamma and the minimum degree, and in this regime the network acts like a random network breaking when a finite fraction of its nodes are removed. For gamma less than 3, <math>\kappa</math> diverges in the limit as N trends toward infinity. In this case, for large scale-free networks, the critical threshold approaches 1. This essentially means almost all nodes must be removed in order to destroy the giant component, and large scale-free networks are very robust with regard to random failures. One can make intuitive sense of this conclusion by thinking about the heterogeneity of scale-free networks and of the hubs in particular. Because there are relatively few hubs, they are less likely to be removed through random failures while small low-degree nodes are more likely to be removed. Because the low-degree nodes are of little importance in connecting the giant component, their removal has little impact. | | For gamma greater than 3, the critical threshold only depends on gamma and the minimum degree, and in this regime the network acts like a random network breaking when a finite fraction of its nodes are removed. For gamma less than 3, <math>\kappa</math> diverges in the limit as N trends toward infinity. In this case, for large scale-free networks, the critical threshold approaches 1. This essentially means almost all nodes must be removed in order to destroy the giant component, and large scale-free networks are very robust with regard to random failures. One can make intuitive sense of this conclusion by thinking about the heterogeneity of scale-free networks and of the hubs in particular. Because there are relatively few hubs, they are less likely to be removed through random failures while small low-degree nodes are more likely to be removed. Because the low-degree nodes are of little importance in connecting the giant component, their removal has little impact. |
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− | 对于大于3的伽玛γ,临界阈值仅取决于伽玛γ和最小度。这种情况下,网络的部分节点被删除,之后该网络会像随机网络瓦解一般。对于小于3的伽玛,随着N趋于无穷大,κ的极限会发散。在这种情况下,对于大型无标度网络,关键阈值接近1。从本质上讲,这意味着几乎要除去所有节点才能破坏巨型组件,该大型无标度网络在应对随机故障方面非常强大。通过考虑无标度网络尤其是枢纽的异构性,可以直观地理解这一点。由于相对较少的枢纽节点,因此不太可能通过随机故障将其删除,而较小的低度节点则更可能被删除。同时由于低度节点在连接巨型部件方面不重要,因此将其移除几乎没有多大影响。
| + | 对于大于3的伽玛,临界阈值仅取决于伽玛和最小度。这种情况下,网络的部分节点被删除,之后该网络会像随机网络瓦解一般。对于小于3的伽玛,随着N趋于无穷大,κ的极限会发散。在这种情况下,对于大型无标度网络,关键阈值接近1。从本质上讲,这意味着几乎要除去所有节点才能破坏巨型组件,该大型无标度网络在应对随机故障方面非常强大。通过考虑无标度网络尤其是枢纽的异构性,可以直观地理解这一点。由于相对较少的枢纽节点,因此不太可能通过随机故障将其删除,而较小的低度节点则更可能被删除。同时由于低度节点在连接巨型部件方面不重要,因此将其移除几乎没有多大影响。 |
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| ==Targeted attacks on scale-free networks== | | ==Targeted attacks on scale-free networks== |