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arXiv 1202.1779cs.SIphysics.soc-phstat.ML
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找到流行病级联图

Finding the Graph of Epidemic Cascades

Praneeth Netrapalli, Sujay Sanghavi

摘要:

我们考虑的问题,找到一个流行病级联传播的图,只有当每个节点被感染的时间。虽然这在离线和在线社交网络、电子商务、流行病学、基础设施网络的脆弱性等多种情况下都是一个重要问题,但在寻找图表方面,无论是分析还是实证工作都很少。显然,仅从一个级联中这样做是不可能的;我们的兴趣是从少量级联中学习图。对于经典的和流行的“独立级联”SIR流行病,我们分析建立的全球最大似然(ML)估计,和一个自然的贪心算法所需的级联数。这两个结果都是基于一个关键的观察:全局图学习问题分解为$n$局部问题--每个节点一个。对于一个节点的程度$d$,我们表明,它的邻居可以可靠地找到,一旦它已被感染$O(d^2 \log n)$倍(ML一般图)或$O(d\log n)$倍(贪婪的树)。我们还提供了一个相应的信息理论下限的$Ω(d\log n)$,因此我们的界限是严格的。此外,如果我们以实际图的超图的形式给出边信息(通常是这种情况),那么在所有情况下所需的级联样本的数量都与网络大小$n$无关。最后,我们证明了对于一个非常一般的SIR传染病级联模型,通过网络图的道德化,得到了传染时间的马尔可夫图。

英文摘要:

We consider the problem of finding the graph on which an epidemic cascade spreads, given only the times when each node gets infected. While this is a problem of importance in several contexts -- offline and online social networks, e-commerce, epidemiology, vulnerabilities in infrastructure networks -- there has been very little work, analytical or empirical, on finding the graph. Clearly, it is impossible to do so from just one cascade; our interest is in learning the graph from a small number of cascades. For the classic and popular "independent cascade" SIR epidemics, we analytically establish the number of cascades required by both the global maximum-likelihood (ML) estimator, and a natural greedy algorithm. Both results are based on a key observation: the global graph learning problem decouples into $n$ local problems -- one for each node. For a node of degree $d$, we show that its neighborhood can be reliably found once it has been infected $O(d^2 \log n)$ times (for ML on general graphs) or $O(d\log n)$ times (for greedy on trees). We also provide a corresponding information-theoretic lower bound of $Ω(d\log n)$; thus our bounds are essentially tight. Furthermore, if we are given side-information in the form of a super-graph of the actual graph (as is often the case), then the number of cascade samples required -- in all cases -- becomes independent of the network size $n$. Finally, we show that for a very general SIR epidemic cascade model, the Markov graph of infection times is obtained via the moralization of the network graph.

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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