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arXiv 1306.3454math.PRmath.CO
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鲁棒偏好连接网络的脆弱性

Vulnerability of robust preferential attachment networks

Maren Eckhoff, Peter Mörters

摘要:

具有小幂律指数的无标度网络被认为是鲁棒的,这意味着它们的定性拓扑结构不能通过随机删除大部分节点而改变。相比之下,科学文献中认为,这种网络非常容易受到有针对性的攻击,删除网络中的少数关键节点将大大改变拓扑结构。本文分析了一类具有鲁棒性的偏好连接网络,并证明了支持这一观点的四个主要结果:在删除任意小比例的最老节点后,(1)渐近度分布具有指数尾,而不是幂律尾;(2)网络中的最大度从网络大小n的幂下降到n的对数;(3)网络中的典型距离从log log n阶增加到log n阶;以及(4)网络变得易受节点的随机移除的影响。重要的是,我们所有的结果都明确量化了对移除顶点的比例的依赖性。例如,我们表明,临界比例的节点,必须保留的生存的巨大的组件经历了急剧增加,作为从零开始移动,并与其他网络的类似结果的比较,揭示了存在两个不同的普适性类的强大的网络模型。在我们的证明中的关键技术是一个局部近似的网络的分支随机游动与两个杀戮的边界,并在这个过程中,进入估计的谱半径的相关运营商的粒子谱系的理解。

英文摘要:

Scale-free networks with small power law exponent are known to be robust, meaning that their qualitative topological structure cannot be altered by random removal of even a large proportion of nodes. By contrast, it has been argued in the science literature that such networks are highly vulnerable to a targeted attack, and removing a small number of key nodes in the network will dramatically change the topological structure. Here we analyse a class of preferential attachment networks in the robust regime and prove four main results supporting this claim: After removal of an arbitrarily small proportion epsilon>0 of the oldest nodes (1) the asymptotic degree distribution has exponential instead of power law tails; (2) the largest degree in the network drops from being of the order of a power of the network size n to being just logarithmic in n; (3) the typical distances in the network increase from order log log n to order log n; and (4) the network becomes vulnerable to random removal of nodes. Importantly, all our results explicitly quantify the dependence on the proportion epsilon of removed vertices. For example, we show that the critical proportion of nodes that have to be retained for survival of the giant component undergoes a steep increase as epsilon moves away from zero, and a comparison of this result with similar ones for other networks reveals the existence of two different universality classes of robust network models. The key technique in our proofs is a local approximation of the network by a branching random walk with two killing boundaries, and an understanding of the particle genealogies in this process, which enters into estimates for the spectral radius of an associated operator.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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