论文标题

有限的内存相互作用Pólya触发网络及其近似动力学系统

A Finite Memory Interacting Pólya Contagion Network and its Approximating Dynamical Systems

论文作者

Singh, Somya, Alajaji, Fady, Gharesifard, Bahman

论文摘要

我们使用相互作用的有限存储器两色Pólyaurn网络引入了一种新模型,用于传染性扩展,我们将其称为有限的内存相互作用的Pólya触发网络。 urn的相互作用是从给定的urn绘制红球(代表感染状态)的概率,不仅取决于该urn中的红球的比例,而且还取决于网络中其他urns中红球的比率,因此考虑了空间竞争的效果。最终的网络范围传染过程是一个离散的有限内存($ m $ th订单)Markov进程,其过渡概率矩阵已确定。分析了网络传播Markov过程的随机属性,对于均匀的系统参数,我们表征了每个URN中感染的限制状态。对于非均匀情况,鉴于随机过程的复杂性,并且具有与经过良好研究的SIS模型相同的精神,我们使用平均场类型近似值来获得一个离散的时间动力学系统,以用于有限的记忆相互作用的PólyaPotagion网络。有趣的是,对于$ m = 1 $,我们获得了一个线性动力学系统,该系统准确代表了相应的马尔可夫进程。对于$ m> 1 $,我们使用均值场近似来获得非线性动力学系统。此外,我们指出后一种动力系统接受了线性变体(通过保留其领先的线性项实现),我们研究了线性系统的渐近行为,用于记忆模式并表征其平衡。最后,我们提出了模拟研究,以评估线性和非线性动力学系统所提供的近似值的质量。

We introduce a new model for contagion spread using a network of interacting finite memory two-color Pólya urns, which we refer to as the finite memory interacting Pólya contagion network. The urns interact in the sense that the probability of drawing a red ball (which represents an infection state) for a given urn, not only depends on the ratio of red balls in that urn but also on the ratio of red balls in the other urns in the network, hence accounting for the effect of spatial contagion. The resulting network-wide contagion process is a discrete-time finite-memory ($M$th order) Markov process, whose transition probability matrix is determined. The stochastic properties of the network contagion Markov process are analytically examined, and for homogeneous system parameters, we characterize the limiting state of infection in each urn. For the non-homogeneous case, given the complexity of the stochastic process, and in the same spirit as the well-studied SIS models, we use a mean-field type approximation to obtain a discrete-time dynamical system for the finite memory interacting Pólya contagion network. Interestingly, for $M=1$, we obtain a linear dynamical system which exactly represents the corresponding Markov process. For $M>1$, we use mean-field approximation to obtain a nonlinear dynamical system. Furthermore, noting that the latter dynamical system admits a linear variant (realized by retaining its leading linear terms), we study the asymptotic behavior of the linear systems for both memory modes and characterize their equilibrium. Finally, we present simulation studies to assess the quality of the approximation purveyed by the linear and non-linear dynamical systems.

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