标题： SIS模型在网络上的阈值和准平稳分布 显示英文标题

标题： The threshold and quasi-stationary distribution for the SIS model on networks

摘要： 我们研究任意网络上的易感-感染-易感（SIS）模型。 已建立的对近似方法精确处理节点的相邻对，而对网络的其余部分进行平均场近似。 我们通过动态扩展状态空间来改进该方法，使节点具有最后一次变为易感的时间记忆。 所得近似方法易于实现，在确定流行病阈值以及计算阈值以上准稳态感染个体的比例方面，对于有限图和无限随机图都表现出高度准确性。 显示英文摘要

摘要： We study the Susceptible-Infectious-Susceptible (SIS) model on arbitrary networks. The well-established pair approximation treats neighboring pairs of nodes exactly while making a mean field approximation for the rest of the network. We improve the method by expanding the state space dynamically, giving nodes a memory of when they last became susceptible. The resulting approximation is simple to implement and appears to be highly accurate, both in locating the epidemic threshold and in computing the quasi-stationary fraction of infected individuals above the threshold, for both finite graphs and infinite random graphs.