基于节点冗余容量动态控制的复杂网络鲁棒性研究

针对传统级联失效模型中冗余参数固定不变的问题,该文综合考虑节点受攻击程度不同和失效过程中网络拓扑的动态变化,建立了基于节点冗余容量动态控制(DRC)的级联失效模型.通过定义网络相变临界因子θ衡量节点失效引发级联失效的概率,分析了网络鲁棒性与θ之间的相关性,并结合度分布函数详细推导了θ的解析表达式,基于解析表达式提出了两种网络鲁棒性提升策略.仿真结果表明,在模型网络和真实网络中,根据被攻击节点度的不同,通过调整节点初始负载参数可以有效提高目标网络的鲁棒性;DRC模型下级联失效传播范围较τ Motter-Lai(ML)模型显著减小.     

互联网网络单节点失效容错特性研究

容错性是大型网络的重要特性,而现有的评测参数难以进行准确的评价。引入路径损失作为评测参数,通过对因特网自治系统（AS,Autonomy System）网络拓扑数据的分析,研究了单节点失效情况下网络的容错特性,并与经典的网络模型相比较。结果表明,AS网络的容错特性表现出网络规模无关性,单节点失效引起的路径损失呈幂率规律变化,度较大和度较小的节点都可能对网络容错性产生较大影响,而现有的网络模型未能成功模拟AS网络的容错特性。     

基于谱分析的复杂网络脆弱节点发现算法

未来以网络为中心的信息化战争,节点打击、毁点瘫面成为攻击敌方信息网络、夺取信息优势的重要手段。针对寻找敌方网络弱点进行攻击、提升我方体系抗毁能力拒止攻击等问题,在复杂网络拓扑连接矩阵的基础上,引入Laplacian谱分析方法,提出拓扑连接度概念,通过计算网络中各节点的拓扑连接度,发现脆弱节点并给出脆弱性排序,为信息网络的健壮性与抗毁性研究提供了一种有效的全新思路。     

负载作用下相依网络择优恢复方法研究

优选节点实施恢复是控制相依网络级联失效的有效措施。针对以往恢复模型未考虑节点负载的情况,该文首先分析了包含依赖失效和过载失效的级联失效过程,构建了负载作用下相依网络恢复模型。然后,基于共同边界节点的结构和动力学属性,提出一种基于容量和连接边的择优恢复(PRCCL)方法。实验结果表明,在无标度相依网络中,PRCCL方法恢复效果明显好于基准方法,恢复时间更短,恢复后的网络具有更高的平均度和鲁棒性;在Power网和Internet网构成的相依网络中,PRCCL方法恢复效果同样优于基准方法;PRCCL方法的优势与恢复比例、负载控制参数成正比,与容忍系数成反比。实验结果验证了PRCCL方法的有效性,对于现实中相依网络恢复工作具有科学指导价值。     

基于边攻击成本的复杂网络鲁棒性研究

传统的复杂网络边攻击策略有效性研究中往往忽略边的攻击成本因素,针对这一问题,文中提出了基于边攻击成本的复杂网络鲁棒性研究方法.该方法将边的攻击成本因素考虑在内,采用边的权重近似衡量边攻击成本,以最大连通子图相对值作为网络鲁棒性度量指标.在考虑边攻击成本时对合成网络和真实网络的鲁棒性进行了研究,并分析了边权重对真实网络鲁棒性的影响.实验结果表明：在边攻击成本较小时,边权由小到大策略攻击网络效果较好;对于合成网络来说,采用边权由大到小攻击策略时,BA（Barabasi-Albert）无标度网络比WS（Watts-Strogatz）小世界网络的鲁棒性强;真实复杂网络鲁棒性可以通过调节边权得到优化.与现有方法相比,利用该方法研究复杂网络鲁棒性较符合实际,仿真实验验证了所提方法的有效性和可行性.     

基于攻击策略的复杂网络拓扑结构优化模型

针对不考虑攻击策略时以自然连通度作为复杂网络抗毁性测度存在的缺陷,用节点的改进总连通度作为目标函数建立了基于按度攻击策略的复杂网络拓扑结构优化模型,并运用收敛速度较快的自适应局部增强微分进化算法(ADMPDE)对复杂网络的拓扑结构优化进行仿真分析。仿真结果验证了该模型的合理性和算法的适用性,优化后的复杂网络的度大节点比例提高了32%,其抗毁性得到明显改进,并得到一些有意义的结论。相关内容可为该领域的进一步研究提供有价值的参考。     

数据库复杂网络构造算法及特征分析

数据库复杂网络是对管理信息系统软件复杂性的一种度量,提供了一种精简的可视化业务逻辑描述,为软件增量设计提供了自说明文档。为抽取数据库复杂网络,提出了两种算法:(1)基于数据表主外键关联的网络构造算法;(2)基于隐性语义关联的构造算法及扩展算法。通过对9个软件数据库的分析,研究了该类网络的统计特性,发现其无标度特性入度分布比出度分布更不均匀,入度大的节点是系统的骨干节点。为精准构造直接辅助软件工程的数据库复杂网络,提出了针对语义隐性关联的一组命名规范。     

复杂网络理论在对等网络特性分析中的应用

基于现有的复杂网络理论,研究了对等网络的复杂特性,并就对等网络中节点度和节点间平均最短路径两个特征参数进行算法设计和仿真.仿真结果表明,对等网络中使用复杂网络理论的特性分析理论结果与实验结果基本一致,能准确反映对等网络的特性.     

基于复杂网络和最优子序列双射的形状描述与匹配

本文结合复杂网络理论分析形状特性,对形状建模成基于形状内部距离的小世界复杂网络,分析复杂网络节点的度特征和聚类系数特征,通过复杂网络的动态演化,构造多尺度的关于节点分布的直方图来描述形状;用轮廓点多尺度的度特征、聚类系数特征和内部距离形状上下文特征来描述轮廓点,结合改进的最优子序列双射算法实现形状匹配.实验中分析了复杂...     

基于随机选择的复杂网络模型研究

复杂网络模型研究对复杂网络学科的发展起着十分重要的作用.本文提出了基于网络节点局域信息随机选择连接节点的复杂网络模型.并通过解析方法计算了网络的度分布.以及仿真分析模型的聚类系数.平均路径长度和网络的社团结构特征.仿真结果表明,本模型生成的网络同时具有小世界特性.无标度特性以及清晰的社团结构特征.已有的研究表明.该模型更加接近现实社会中的网络.     

TCP/IP协议簇的复杂网络结构

应用复杂网络理论，针对TCP／IP协议簇的内在关系，以协议规范文档为节点。协议间的引用关系为边，构造网络图并分析其节点度分布、平均最短路径和群集性质。研究发现，协议间的引用关系具有复杂网络的基本特征：幂律分布、小世界效应和大群集效应。图分割计算的结果，表明协议间互引用关系网络比分层结构具有更丰富的局部特征。     

The study on degree distribution property of complex network based on cooperative communication

Complex networks have been widely studied. Recently, many results show that the degree dis-tributions of some large networks follow the form of power-law and these networks possess better robust-ness against random nodes failure. As an effective technology on combating the channel fading, wireless co-operative communication is becoming one of the most important methods to improve the wireless communi-cation performances. In this paper, the complex network models based on cooperative communication and non-cooperative communication are established; and the degree distribution properties for them are studied. The simulation results show that the degree distributions of these networks also follow the form of power-law, which means that the addition of cooperative communication links will not change the property of degree distribution and then these networks will possess better robustness against random nodes failure as well.     

Superpixels extracted via region fusion with boundary constraint

In this paper, we present an accurate superpixel algorithm by region fusion with boundary constraint (RFBC). Superpixels with regular shape and high boundary adherence can be generated in weak boundary and complex texture regions through our algorithm. RFBC includes two steps which are initial segmentation and region fusion respectively. In initial segmentation, broken Canny edges are connected through edge closing algorithm. Subsequently, the closed Canny edges and SLIC superpixel edges are combined together to form the incipient superpixels. In region fusion, gray Gaussian distribution and adjacent relation are used as priori to compute the degree of similarity across incipient superpixels in GBP algorithm. For concreteness, the information of similarity is propagated between regions and the most similar regions are fused, which are accomplished alternatingly to preserve accurate boundaries. Extensive experiments on the Berkeley segmentation benchmark show that the proposed algorithm outperforms the most state-of-the-art algorithms.     

Electromagnetic Topology: An Additional Interaction Sequence Diagram for Transmission Line Network Analysis

The electromagnetic analysis of complex transmission line networks requires sophisticated modeling tools. Although the existing ones are useful, handling real-scale networks is still a challenge, hence requiring additional analysis tools. A new interaction sequence diagram called the coupling order graph (COG), which is able to quantify further approximations in complex situations, is presented. Its construction is based on the conventional interaction sequence diagram of electromagnetic topology (EMT). In this diagram, vertices are physical wires, and edges account for the interactions between them. This is an oriented graph that describes a source-victim interaction sequence. Introducing a weak coupling approximation, this interaction sequence appears as a set of parallel paths. Prior to any calculation, each of these paths may be analyzed in terms of bounded topological S parameters and its number of associated edges. An approximate answer is then obtained through the aggregation of predominant paths only. We illustrate the COG advantages through an arbitrarily chosen example. It is shown that approximate evaluations can be obtained from the subnetworks that are far simpler than the original one. In addition, we provide an example of a criterion that quantifies this approximation     

Methods of theoretical analysis and computer modeling of theshaping of electrical pulses by nonlinear transmission lines andlumped-element delay lines

The mechanism by which high-power electrical pulses can be sharpened by propagation along nonlinear transmission lines and lumped-element delay lines is described with emphasis on the production of pulses with very fast leading or trailing edges. A survey of some of the mathematical techniques that have been applied to the propagation of electrical signals along nonlinear lines and ladder networks is presented, and the limitations of these techniques are discussed. The processes that both produce and limit pulse sharpening on nonlinear lumped-element delay lines are examined, and it is found that the wave equation, which describes the propagation of electrical signals along such networks, predicts that an electrical pulse will decompose into an array of solitons. An approximate formula for estimating the degree of pulse sharpening that can be produced on a delay line with a given number of sections is derived, and its accuracy is compared with experimental results. Numerical integration techniques for solving the nonlinear differential and difference equations that result from the mathematical analysis of nonlinear lines and networks are discussed, and the propagation of a voltage pulse along a lumped-element delay line containing nonlinear capacitors is simulated using a computer model based on an efficient algorithm     

一种融合局部拓扑影响力的时序链路预测算法

链路预测旨在发现复杂网络中的未知连接和未来可能的连接,在推荐系统等实际应用中具有重要作用.考虑到许多真实网络的时序特性,时序链路预测逐渐成为研究热点.当前,基于时间序列分析的方法往往忽略了网络演化过程对网络本身的影响,而基于静态网络演化的方法大多仅考虑了局部连边的演化影响,对网络拓扑结构的演化特性挖掘有限.针对上述问题...     

基于粒子群优化算法的复杂船舶电力系统脆性研究

针对复杂船舶电力系统的研究,提出一种复杂系统脆性分析的方法。建立了复杂船舶电力系统脆性的赋权图模型,以图的边描述子系统之间的脆性联系,边的权值描述子系统之间的脆性联系程度,并且定义了系统最大崩溃路径,提出了一种求解系统最大崩溃路径的粒子群优化算法。为了进一步说明问题,又以Matlab仿真为例验证了新算法,并对算法中参数的选取进行了讨论。     

复杂网络与可扩展路由

互联网规模扩大,相应路由表大小呈指数增加,形成下一代互联网可扩展路由“瓶颈”。基于复杂网络和可扩展路由的相关理论与主要策略,文章对相关研究成果。如小世界效应所表现出来的特性、小世界和无标度网络模型,网格、层次及隐藏度量等3种可扩展路由网络模型,随机游走、贪婪、最大度、优先、本地介数、距离与度及相似性与度混合等多种路由策略等进行了分析与归纳。这些研究结果和方法为因互联网规模不断扩大所带来的路由系统可扩展性问题提供解决方案     

On the design of self-organized cellular wireless networks

It has been observed that complex networks such as the Internet, World Wide Web, social networks, and biological systems are self-organizing in nature and exhibit some common properties such as the power law degree distribution. Recently, two models (i.e., small world and scale-free network models) have been proposed and successfully used to describe the nature of such networks. In this article we investigate whether these concepts can also be applied to cellular wireless networks, which typically do not exhibit self-organizing or scalability properties due to the limited range of the wireless nodes. Our ultimate goal is to design robust, reliable, scalable, and efficiently utilized wireless networks via self-organizing mechanisms.