电力基础设施网络级联毁伤传播算法

级联毁伤是对电力基础设施网络局部打击引发的毁伤传播和大面积级联瘫痪现象,实际为具有依赖关系的实体之间的行为交互和毁伤传播过程.为仿真研究战争危机条件下的电力基础设施网络毁伤综合效果,依据复杂系统实体的交互依赖关系和毁伤传播机理,设计实现了电力基础设施网络节点级联依赖度生成算法和级联毁伤传播算法.通过实例计算分析和仿真,结果较好地体现出电力基础设施网络级联毁伤的动态演化过程,有效满足了战争仿真中对上述类型网络毁伤综合效果的分析需求.     

病毒传播下的因特网级联故障模型构建与仿真

级联故障普遍存在于复杂网络系统中,为了更好控制IPv6因特网级联故障问题,首先分析了2014年IPv6因特网数据的拓扑特征;其次,探讨了在因特网的数据通信过程中,病毒传播与级联故障之间的相互作用问题：比如,蠕虫病毒的传播会引起负载变化,致使网络中负载重分配,从而导致级联故障的发生,同时,级联故障的发生,导致路由器的相继失效,也会导致病毒无法传播;最后,在此基础上,提出一种新的基于负载局部重分配原则的级联故障模型,并建立了SIR病毒传播和级联故障的相互作用模型——SIR-C模型,通过构建Netlogo动态仿真系统,验证了SIR-C模型的正确性与有效性,可以为因特网拓扑结构与路由策略的管理与优化提供理论参考。     

考虑个体警觉行为的双层网络流行病传播模型

流行病传播过程中常伴随个体意识信息的扩散,然而目前关于流行病与意识信息关系的研究大部分未考虑意识信息在传播过程中对个体接触行为的影响。提出一种基于个体警觉状态的双层网络流行病传播模型。建立下层物理接触网络描述流行病的传播,构建上层信息扩散网络描述流行病传播中信息扩散,根据个体的行为偏好和警觉性设计警觉个体避免与非警觉个体接触、警觉个体避免与警觉个体接触两种接触行为策略,并在BA-BA、BA-WS和WS-WS 3种双层网络中模拟两种行为策略对流行病传播的影响。仿真结果表明,该模型中两种个体警觉行为策略通过调节警觉性参数均能有效降低流行病感染规模并提高流行病爆发阈值,从而抑制流行病在人群中传播。     

物流网络级联失效下的抗毁性分析

物流网络在突发事件下易发生级联失效现象,给网络的抗毁性带来巨大影响。针对物流网络中级联失效扩散机理的认知对于提高应急对策的有效性及控制效率具有重要意义。因此基于物流网络特征构建级联失效模型,分析研究级联失效的传播对物流网络抗毁性的影响。数值仿真结果表明：以物流中心为代表的II类中转型节点的失效对网络抗毁性的影响最大。物流节点间业务联系紧密程度及网络结构均对网络抗毁性产生重要影响。     

基于转发效应的自媒体网络舆情扩散

随着无线网络技术的发展与手机网民人数的激增,以微信、微博等新媒体为平台的自媒体网络舆情逐渐取代传统媒体舆情,成为舆论场上的主导力量,并对社会的稳定产生了重要影响.基于此,首先界定自媒体网络舆情转发网络的相关概念,论述转发网络的转发效应;然后剖析自媒体网络舆情转发效应的影响因素,构建基于转发效应的自媒体网络舆情扩散模型,并在此基础上,对舆情扩散模型进行了仿真分析.通过仿真分析发现,转发网络中的超级群组是自媒体网络舆情迅速扩散的中心和节点,使得自媒体网络舆情扩散出现了明显的动态舆情级联特征,进而使其在出现、增长与稳定等阶段具有发散性特征,并以合并、超级群组和集中式拓扑结构等效应形式进行着扩散和传播.     

社会网络中基于核函数的信息传播模型

摘 要: 传统的社会网络信息传播模型假设整个网络结构是已知的,并在已知的网络上分析信息的动态传播,然而实际的社会网络往往是不完全的。为了研究信息在不完全社会网络上的信息传播,本文提出了一种基于核函数的信息传播模型。首先,根据信息传播在社会网络中的级联关系将网络中的节点映射为到连续的特征空间,并通过节点间的距离反应节点的传播顺序。其次,将信息在网络中的传播描述为特征空间中的能量扩散过程,并采用随机梯度下降法进行优化求解。最后,将信息的内容加入到目标特征空间中,并给出了相应的核函数。实验表明,本文提出的信息传播模型与相关的模型相比较不仅可以弥补社会网络的不完全性,还具有更高的预测性能。     

复杂网络上具有多感染阶段的传染病传播模型

针对传染病传播模型缺乏多感染阶段的不足,结合SIR和SEIR两种传播模型的特性,提出了一种改进的具有多感染阶段的SIR传染病传播模型(即SInR模型)。该模型充分考虑了不同感染阶段的非均匀感染力对不同网络结构上传染病传播及传播阈值的影响;同时引入相对感染力及传播时间尺度的概念,从网络结构、网络规模及相对感染力方面进行了仿真研究。仿真中无标度网络采用BA模型的生成算法,而小世界网络采用WS模型的生成算法。由仿真可知,感染节点在整个感染过程中大致服从泊松分布,因此在SInR模型下无标度网络的传播速度更快,范围更广;相对感染力对于传染病的大规模爆发存在着一个阈值,当感染力大于阈值时传染病才能大范围地爆发传播,而小于阈值时传染病只会局域小范围传播直至消失,无标度网络的感染力阈值为0.2,小世界网络的感染力阈值为0.24;随着网络规模的增大,传播时间尺度也在增大,相应的传播速度就会降低。仿真结果表明:该模型下无标度网络传染病传播速度更快且影响范围更大;无标度网络的相对传染力的传播阈值小于小世界网络,设置合理阈值有利于降低传染病的传播影响力。     

综合节点邻域信息下的物流网络级联失效模型构建及分析

级联失效对物流网络的安全运作具有重要影响。基于节点领域信息构建相应的级联失效模型, 分析研究物流网络的级联失效问题。数值仿真结果表明：较低的安全负载能力配置可很大程度上抵御级联失效的破坏; 重要度越大的节点的失效对网络的平均破坏程度越大; 节点平均度越大的网络结构对级联失效的抵御能力越强。这可为物流网络应急规划及应急控制研究提供理论指导。     

无线通信网络的建模及故障传播

针对级联故障在网络数学模型中展现的局限性,基于复杂网络和图论的基本原理,对无线通信网络进行建模,并对网络中的故障传播进行研究。根据复杂网络中的无标度模型,建立由网络节点和通信信道组成的线图模型。针对无线通信网络中的级联故障,分别从网络故障等级、节点容错能力大小、初始故障节点数目等方面研究故障在通信网络中的传播情况。仿真结果表明,线图模型能够更直观地体现网络特性,同时故障参数会影响级联故障在通信网络中的传播。     

多层供应链网络中欠载失效和过载级联失效的协同演化研究

供应链网络与我们的生活密切相关,而供应链网络的级联失效问题一直是研究的重点.文中提出了一种多层供应链网络混合失效模型,更好地模拟了真实供应链网络欠载失效和过载级联失效的过程,为预防供应链网络崩溃提供了参考.首先,建立了上层供应商网络过载级联失效模型和下层零售商网络欠载失效模型,它们共同构成了上下层网络混合的供应链网络模型;然后,通过采用不同的攻击方式攻击上下层网络,分析了供应链网络的失效迭代过程和脆弱性.在初始攻击比例一定的情况下,上层供应商网络相较于下层零售商网络有更强的鲁棒性,初始攻击节点为上层供应商网络节点时,网络崩溃的阈值更低,更容易使供应链网络发生全面崩溃.仿真结果验证了模型的有效性,为预防供应链网络崩溃提供了新的研究模型.     

State and Network Structures of Stock Markets Around the Global Financial Crisis

We consider the effects of the 2008 global financial crisis on the global stock market before, during, and after the crisis. We generate complex networks from a cross-correlation matrix such as the threshold network (TN) and the minimal spanning tree (MST). In the threshold network, we assign a threshold value by using the mean and standard deviation of cross-correlation coefficients. When the threshold is equal to the mean of these coefficients, we observe a giant cluster composed of three economic zones in all three periods. We find that during the crisis, the countries in the Asian zone were weakly connected and those in the American zone were tightly linked to the countries in the European zone. At a large threshold, the three economic zones were fragmented. The European countries connected tightly, but the Asian countries bound weakly. The MST constructed from the distance matrix. In the MST, France remained a hub node in all three periods. The size of the MST shrank slightly during the crisis. We observe a scaling relation between the network distance of nodes from the central hub (France) and the geometrical distance. We observe the topological change of the financial network structure during the global financial crisis. The TN and MST are complementary roles to understand the connecting structure of financial complex networks. The TN reveals to observe the clustering effects and robustness of the cluster during the financial crisis. The MST shows the central hub and connecting node among the economic zones.     

Effects of redundant systems on controlling the disaster spreading in networks

Many systems in our life contain redundant systems. If one system collapses, its redundant system will substitute it to work for a period of time. In our paper, we have specifically studied the effects of redundant systems on controlling the disaster spreading in networks. Based on the network structure, several redundant strategies have been formulated. On the one hand, the effects of the redundant systems designed uniformly have been studied in different types of networks, the result shows that the random network has been improved the best to fight the disaster. On the other hand, the effectiveness of those redundant strategies have been discussed in the scale free network, results show that the strategy based on total degree is the most effective one to control the spreading. All results found in this paper offer promising perspectives to design redundant systems for preventing cascading failures.     

一种信息高速公路环境

进入９０年代以来，Ｉｎｔｅｒｎｅｔ已成为国际性计算机网络，并得到了迅猛发展。许多国家和地区纷纷建立自己的Ｉｎｔｅｒｎｅｔ节点，并与国际互连，以获取各种科技、经济信息，大有千流归海之势。我们予近期通过Ｉｎｔｅｒｎｅｔ服务节点，在四川省建成了一种信息高速公路环境。本文就四川省Ｉｎｔｅｒｎｅｔ服务节点硬件环境、软件环境和连入Ｉｎ－ｔｅｒｎｅｔ的方法等作简要介绍，旨在与同行商榷、与用户探讨，建好信息高速公路，为四川服务。     

The e-business capability of small and medium sized firms in international supply chains

The reality of trade is that it takes two or more parties to do business, and therefore the capabilities of both selling and buying firms are important. Where over 60% of Small and Medium Enterprises (SMEs) in the USA and Canada have adopted some form of business process through a computer mediated network, such as the Internet, other countries have significantly lower adoption rates. In Asia and Latin America, where as many as 99% of all firms are classified as SMEs, low adoption rates may be an impediment to increased international trade. This paper takes a critical look at the existing research on adoption of e-business technology by SMEs internationally. In particular, we identify the gap in our knowledge about what makes SMEs in different countries capable of using the technology in their domestic and international supply chains. We present a typology of the business processes networked over computer-mediated processes from our preliminary empirical field research, interviewing 40 SMEs in Canada, Japan, China and Mexico. This is used to propose a model of international SME capability to guide future empirical research.     

Quadratic approximation based differential evolution with valuable trade off approach for bi-objective short-term hydrothermal scheduling

Short-term combined economic emission hydrothermal scheduling (CEES) is a bi-objective problem: (i) minimizing fuel cost and (ii) minimizing pollutant emission. In this paper, quadratic approximation based differential evolution with valuable trade off approach (QADEVT) has been developed to solve the bi-objective hydrothermal scheduling problem. The practical hydrothermal system possesses various constraints which make the problem of finding global optimum difficult. In this paper, heuristic rules are proposed to handle the water dynamic balance constraints and heuristic strategies based on priority list are employed to handle active power balance constraints. A feasibility-based selection technique is also introduced to satisfy the reservoir storage volumes constraints. To demonstrate the superiority of the proposed approach, simulation results have been compared with those obtained by differential evolution (DE) and particle swarm optimization (PSO) with same heuristic strategies and the earlier reported methods available in literature. The simulation results reveal that the proposed approach is capable of efficiently providing superior solutions.     

带恢复策略的复杂网络级联失效机理及鲁棒性研究

为研究复杂网络在遭遇随机故障或蓄意攻击时的鲁棒性,考虑节点具有恢复和重复失效等特征,构建故障节点概率传播模式下的级联失效模型.构建节点故障概率随故障次数增加而逐渐降低的故障概率函数,设计概率恢复(R)和阶段恢复(T)两种故障节点恢复策略,并针对ER、WS、NC和BA四类网络研究其恢复鲁棒性.仿真实验考虑模型中相关参数变化,揭示其对复杂网络级联失效过程中的鲁棒性影响,综合分析边鲁棒性和节点鲁棒性的性能权衡.仿真结果表明,在概率恢复策略下,随着恢复率的增大,4类网络级联失效的规模均能够实现有效降低;而在阶段恢复策略下,随着参数T值增加到不同阈值,4类网络鲁棒性指标在级联失效过程中均能够呈现出突变现象.     

Uncovering and predicting the dynamic process of information cascades with survival model

Cascades are ubiquitous in various network environments. Predicting these cascades is decidedly nontrivial in various important applications, such as viral marketing, epidemic prevention, and traffic management. Most previous works have focused on predicting the final cascade sizes. As cascades are dynamic processes, it is always interesting and important to predict the cascade size at any given time, or to predict the time when a cascade will reach a certain size (e.g., the threshold for an outbreak). In this paper, we unify all these tasks into a fundamental problem: cascading process prediction. That is, given the early stage of a cascade, can we predict its cumulative cascade size at any later time? For such a challenging problem, an understanding of the micromechanism that drives and generates the macrophenomena (i.e., the cascading process) is essential. Here, we introduce behavioral dynamics as the micromechanism to describe the dynamic process of an infected node’s neighbors getting infected by a cascade (i.e., one-hop sub-cascades). Through data-driven analysis, we find out the common principles and patterns lying in the behavioral dynamics and propose the novel NEtworked WEibull Regression model for modeling it. We also propose a novel method for predicting cascading processes by effectively aggregating behavioral dynamics and present a scalable solution to approximate the cascading process with a theoretical guarantee. We evaluate the proposed method extensively on a large-scale social network dataset. The results demonstrate that the proposed method can significantly outperform other state-of-the-art methods in multiple tasks including cascade size prediction, outbreak time prediction, and cascading process prediction.     

基于负载容量的计算机网络级联失效模型

基于计算机系统初始化负载能力、路由控制策略与节点转发速率,针对级联失效在计算机系统网络服务性能上的影响,构造一种考虑服务性能的计算机网络级联失效模型。该模型从多个影响参数层面考虑,有效衡量级联失效对于计算机网络服务性能的影响因素变量值。通过综合分析,该模型对于防控网络级联失效问题能够给予一定的实践指导。     

Emergence and stability of key currency in artificial international trade

In this research, we tackled the emergence and stability of key currency when economic strength countries was equal. We propose an artificial international market model with currency credibility as the standard selected for payment. We constructed multiple markets based on the X-Economy System. Through simulations, we found the possibility that key currency could emerge in a symmetric situation, and market and the specialization of production could be stabilized by foreign exchange trade.