Threshold analysis of the susceptible-infected-susceptible model on overlay networks

In this paper, we study epidemic spreading on overlay networks in which n multiple sets of links interconnect among the same nodes. By using the microscopic Markov-chain approximation (MMA) approach, we establish the conditions of epidemic outbreak for two kinds of spreading mechanisms in such an overlay network: the concatenation case and the switching case. When a uniform infection rate is set in all the subnetworks, we find the epidemic threshold for the switching case is just n times as large as that of concatenation case. We also find that the overlay network with a uniform infection rate can be considered as an equivalent (in the sense of epidemic dynamics and epidemic threshold) weighted network. To be specific, the concatenation case corresponds to the integer weighted network, while the switching case corresponds to the fractional weighted network. Interestingly, the time-varying unweighted network can be mapped into the static weighted network. Our analytic results exhibit good agreement with numerical simulations.     

供需模型在众包平台定价中的应用

以众包平台为对象,基于已有数据,考虑供求关系,通过因子分析法对原始数据加以处理,建立任务的定价模型.在实际应用中,可以对分布密集的任务进行打包,并给出针对这种情况的定价模型.结果表明:提出的模型不仅考虑了会员人数与任务数量的关系,还考虑了个人需求的差异,提高了任务的完成度,对众包平台定价的发展与完善有着重要的意义.     

Quality of service statistics over heterogeneous networks: Analysis and applications

Heterogeneous wireless/wired networks and ubiquitous environments are gaining ever more attention by research community. To properly control and manage such puzzles a deep knowledge of quality of service parameters is needed and, therefore, a complete and robust performance assessment is necessary. This paper deals with a performance evaluation and measurement of a number of heterogeneous end-to-end paths taking into account a wide range of statistics. To study the behavior of QoS parameters, an active measurement approach has been introduced for the analysis of properties we called (i) concise statistics (mean, standard deviation, inter quantile range, minimum, maximum, and median) and (ii) detailed statistics (Probability Density Function, Auto-correlation Function, Entropy, Complementary Cumulative Distribution Function, and Bivariate Probability Density Function). We show how, thanks to this view on QoS statistics, a more complete understanding of QoS parameters behavior is possible. In addition, we show how the measured statistics can be fruitfully used in the context of network control and management. More precisely, we present two proof of concepts regarding frameworks for QoS-based anomaly detection and for QoS-based identification of network elements.     

Optimum synthesis of discrete capacitated networks with multi-terminal commodity flow requirements

Network design problems arise in a wide range of applied areas including telecommunications, computer networks, and transportation. In this paper, we address the following discrete capacitated multi-terminal network design problem. Given a connected digraph G = (V,A), a set of L potential facilities to be installed on each arc, and a set of K multi-terminal (non-simultaneous) commodity flow requirements, the problem is to find a set of facilities to install in order to route the K nonsimultaneous flows while minimizing the total fixed plus variable costs. We describe an exact procedure for solving this problem based on Benders decomposition. Our algorithm includes several features that significantly improve the efficiency of the basic approach. Computational results attest to the efficacy of the proposed algorithm, which can solve medium- to large-scale problems to optimality.     

Measuring agility of networked organizational structures via network entropy and mutual information

While the agility of networked organizational structures is important for organizational performance, studies on how to evaluate it remain scant, probably because the difficulty in measuring network evolution. In this conceptual paper, we propose two measures - network entropy and mutual information - to characterize the agility of networked organizational structure. Rooted in graph theory and information theory, these two measures capture network evolution in a comprehensive and parsimonious way. They indicate the uncertainty (or disorder) at the network level as well as the degree distribution at the individual level. We also propose an algorithm for applying them in the scenario of adding links to a network while holding the number of nodes fixed. Both simulated and real networks are used for demonstration. Implications and areas for future research are discussed in the end.     

一类非线性双曲-抛物耦合问题的A.D.I.Galerkin方法

1　引　言考虑三维非线性双曲 -抛物耦合初边值问题 :utt- . (a1 (X,t,u) u) +b1 (X,t,u,v) . u　　　　 +α1 e. v =f(X,t,u,v) ,X∈Ω,t∈ J.vt-a2 Δv +b2 (X,t,u,v) . v　　　　 +α2 e. ut=g(X,t,u,v) ,X∈Ω,t∈ J.u(X,t) =v(X,t) =0 , X∈ Ω ,t∈ J.u(X,0 ) =u0 (X) ,ut(X,0 ) =ut0 (X) ,v(X,0 ) =v0 (X) ,X∈Ω.(1 .1 )其中 ,X=(x1 ,x2 ,x3) ,Ω=(c1 ,d1 )× (c2 ,d2 )× (c3,d3)为 R3中矩形区域 ,边界 Ω . J=[0 ,T] ,T>0为一正常数 .b1 ,b2 ,f,g均为已知光滑函数 (其中 b1 ,b2 为向量函数 ) ,且关于 u,v满足 L…     

结构开放式神经网络及其应用

将传统模式识别神经网络与人类认知的方式相结合,提出了结构开放式模式识别神经网络的概念,并设计了结构开放式模式识别神经网络的体系结构.与传统模式识别神经网络相比,这种神经网络不但提高了神经网络的学习记忆功能,而且在利用计算机实现智能化时大大减少了数据结构的数据量.为了能够更容易的理解这种网络,并针对一类特殊情况的应用进行研究,设计了一个结构开放式模式识别神经网络的结构和操作流程,并通仿真试验,证明了这种网络的有效性和实用性.     

A network efficiency measure with application to critical infrastructure networks

In this paper, we demonstrate how a new network performance/efficiency measure, which captures demands, flows, costs, and behavior on networks, can be used to assess the importance of network components and their rankings. We provide new results regarding the measure, which we refer to as the Nagurney–Qiang measure, or, simply, the N–Q measure, and a previously proposed one, which did not explicitly consider demands and flows. We apply both measures to such critical infrastructure networks as transportation networks and the Internet and further explore the new measure through an application to an electric power generation and distribution network in the form of a supply chain. The Nagurney and Qiang network performance/efficiency measure that captures flows and behavior can identify which network components, that is, nodes and links, have the greatest impact in terms of their removal and, hence, are important from both vulnerability as well as security standpoints.     

Performance analysis of multi-frame message spreading in delay tolerant networks

Communication opportunities in delay tolerant networks are uncertain, so the message is transmitted in a store-carry-forward way, which depends on the contact between nodes. To use the contact efficiently, the message is often divided into many bundles, which are very small and can be transmitted successfully in one contact. Such multi-frame spreading algorithm is very important, but state of the art works just assume that the message is very small and has only one bundle. This paper proposes a theoretical framework based on mean field limit to evaluate the epidemic-like multi-frame spreading algorithm for the first time. In addition, the selfish behaviors can have certain impact on the store-carry-forward communication mode, so we extend our model to the case that nodes are selfish. Simulations show the accuracy of our model. Numerical results show that the more bundles the message has, the lower the average delivery ratio will be. In addition, the selfish behaviors can make the performance be worse.     

渗流耦合系统动边值问题特征差分方法及其应用

油气运移、聚集史软件的功能是重建盆地发育中油气资源运移、聚集的历史,它对合理评估油气资源的勘探和开发有重要的价值．其数学模型是一组多层对流扩散耦合系统的动边值问题．提出一类特征差分格式,得到最佳阶误差估计结果．对这一领域的模型分析、数值方法和软件研制均有重要的理论和实用价值．     

Geometrical Aspects of Discrimination by Multilayer Perceptrons

We investigate some geometrical aspects of the discriminant functions of the kindf_p(x)=∑^p_k=1 c_kτ(a′_kx) for suitable constantsa_k, c_kwhereτis a sigmoidal transformation. This function is realized by a multilayer perceptron with one hidden layer. These results are applied in the analysis of the discriminating power off_p. In particular, we prove that the class of finite populationsΩ₁andΩ₂that can be distinguished byf_pis monotonically increasing inpand we give a minimal sufficientpleading to a complete separation betweenΩ₁andΩ₂.