基于贝叶斯网络的健壮社团检测

健壮社团是复杂网络社团结构中稳定部分,健壮社团发现是非常困难的;提出了一种基于贝叶斯网络推理的健壮社团发现算法,把健壮社团发现问题当做推理问题,构造一个贝叶斯网络,根据结点的度来设置贝叶斯网络相关参数,然后将某些内部联系特别紧密的网络结点设为证据结点,在贝叶斯网络中进行信度传播,得到在已知证据的情况下其余结点属于该健壮社团的概率,最后得到复杂网络中的所有健壮社团;对足球俱乐部网络(115个结点)和随机网络(128个结点)的测试结果表明所提方法能有效地检测出复杂网络中存在的健壮社团,具有较好的应用价值。     

一种改进的Agent学习迁移策略

本文介绍一种改进的学习迁移策略能在能描述运行环境动态变化的有向图中寻找最短路经,根据探测A- gent获得的不同时刻结点状态信息和以往的旅行计划,利用自适应遗传算法规划出一组最佳迁移路径。解决了学习迁移策略由于结点失效导致的迁移失败。该策略能适应复杂的动态网络环境,动态路由,及时自主地修改迁移路线。实例验证了该方法的有效性。     

一种保持Ad hoc网络拓扑特性的拓扑维护策略

无线Ad hoc网络中在结点发生异动的情况下,通常采用局部网络的重构来维持网络的连通性。提出了一个能保证网络连通,维持拓扑结构性能的拓扑维护策略,该策略能够为基于位置信息的拓扑控制算法增加自维护功能。理论分析和实验表明,新的策略只需增加一定维护开销,即可保持拓扑结构在结点度、功率有效性、能耗扩展因子等方面的最佳性能。     

基于度分布的复杂网络拓扑结构的构造

构造网络的拓扑结构是网络仿真的重要前提和基础,拓扑结构对网络仿真结果有重要影响.目前,大多数复杂网络拓扑结构的构造主要是以规则网络或随机网络为基础,但最近的研究表明现实世界中的大多数复杂网络都具有无标度特性,即节点度分布服从幂率(p(k)～k-λ).新的发现给复杂网络拓扑结构的构造提出了新的课题.文中通过引入度秩函数,提出了一种基于度分布的构造复杂网络拓扑结构的新方法,该方法可构造出包括无标度网络在内的具有任意度分布的复杂网络拓扑结构.以无标度网络和指数网络为例,验证了该方法的有效性.     

弹性Web Cache集群的自适应负载均衡策略

在Web cache集群中,Web突发请求的频繁出现引发资源供给不足,造成系统性能显著下降.为有效处理Web突发请求,构建了同时使用本地资源和云资源的弹性Web cache集群.在弹性Web cache集群中,为提升系统性能,降低费用,提出一种自适应的负载模型.该模型可以动态自适应地调整,能够有效适用于异构Web cache集群.考虑到云结点的网络延迟,修正该模型得到云结点负载模型.基于以上负载模型,构造弹性Web cache集群的自适应负载均衡策略.与其他负载均衡策略相比较,使用该自适应负载均衡策略能够在弹性Web cache集群中实现高效的负载均衡.     

基于混合信息的复杂网络路由策略研究

为了确保通讯网络上信息更快更有效的传榆且通讯能力尽可能增大,以无标度网络为平台,提出了一种新的混合路由策略.该策略综合利用了网络动态信息和静态信息,并将网络中结点的传递能力设定为与结点的度相关的变量,采用优化的信息包传递概率模型来研究网络通讯能力,通过对可变参数a的调控可以使网络通讯能力达到最大值.实验结果表明,当α=-4时,网络的路由效率最高.通过与其它路由策略对比证实该路由策略有效地提高了通讯网络的路由效率.     

时变复杂动力学网络的同步控制

研究时变复杂动力学网络的同步控制问题.假定网络模型中的同步轨迹及耦合配置矩阵、内部耦合矩阵的各元素均有界,当这些界值可以预估或不确定时,分别应用线性反馈控制和自适应反馈控制策略使该网络实现全局同步.通过构造Lyapunov函数,证明了对于任意初始状态的时变复杂动力学网络模型在相应的控制手段下总可以实现渐近同步.特别是设计的自适应反馈控制策略对网络的拓扑结构、节点间的耦合强度及时滞等因素表现出较强的鲁棒性.数值仿真证实了上述结论的有效性.     

基于Hilbert曲线的双层覆盖网模型

资源定位和负栽均衡是P2P网络系统中急需解决的核心问题。本文给出的模型将连续相邻的结点组成一个无结构的结点组，结点组之间利用Chord协议连接成为一个全局结构化的环形拓扑结构，并在该拓扑结构中引入HBLS资源查找算法和动态负载均衡双层环状模型调度策略。整个方案不仅具有很好的负载平衡特性，而且为查找提供了充分的灵活性性。仿真实验表明，该模型在资源定位和负载平衡两个方面都优于原Chord。     

输出耦合的复杂网络自适应脉冲同步

应用自适应脉冲控制策略实现输出耦合复杂网络的同步.通过构造Lyapunov泛函,设计合适的自适应脉冲控器,并利用脉冲微分方程理论,建立了网络的同步准则.该准则保证了动态网络渐进同步于任意指定的网络中的单独节点的状态.数值模拟表明所得控制器的有效性.     

一种基于多重覆盖的结构化P2P搜索

本文提出了一种基于多重覆盖的结构化P2P搜索策略,mDOS(multi-Dimensional Overlays based Search).mDOS模拟社会网络中的小世界模型,根据结点的多重属性将结点组织成为多维树型结构.每一维上的任意两个结点根据其在树型结构中的位置形成语义距离.按照覆盖网络中实际距离与语义距离之间的一定函数关系构造多重覆盖网络.邻居结点和目标结点之间在网络中的实际距离可以通过他们的语义距离估计得到,形成基于结点属性的路由方向感.两个结点的有效距离取值多维中的最短语义距离.多重覆盖中的一个结点可以桥接在不同维上的邻居结点,缩小结点之间的平均有效距离,进而缩短搜索路径长度.mDOS还引入索引内容"懒惰维护"机制和路由表"被动修改"机制以克服结点动态性带来的覆盖网络维护代价.最后的实验表明mDOS可以降低搜索路径长度,降低维护代价,提高可用性.     

Asymptotical Synchronization of Coupled Nonlinear Partial Differential Systems With Impulsive Effects

This paper considers the asymptotical synchronization of coupled nonlinear impulsive partial differential systems (PDSs) in complex networks. The cases of both complex networks with fixed topology and switching topology are studied. Based on the Lyapunov–Krasoviskii functional method, sufficient conditions are presented to guarantee the asymptotical synchronization of nonlinear impulsive PDSs, under the cases of fixed topology or switching topology. The effect of the spatial domain is exhibited in these sufficient conditions. Moreover, these sufficient conditions provide a method for selecting a suitable impulsive strategy for the coupled PDSs to achieve the asymptotical synchronization. Finally, numerical examples are given to illustrate the correctness.     

能源混沌系统的主动滑模同步控制

研究了一类能源混沌系统的同步问题。基于主动控制理论与滑模控制理论,给出了一种主动滑模控制器的设计方案。由于闭环误差系统依赖于控制器的参数,所以可通过调节这些参数使误差系统渐近稳定,从而实现了能源混沌系统的渐近同步。数值仿真结果说明了所设计方法的有效性与可行性。     

复杂网络的同步及保密通信

本文以当前的研究热点复杂网络为背景．用Lyapunov稳定性理论和矩阵变换研究了网络中互相耦合的三个节点的混沌同步，提出了一种全局混沌同步方案，并在同步的基础上研究了节点之间的保密通信，最后利用Matlab软件进行数值仿真．仿真结果表明了该方法的有效性．     

Multi-weighted Complex Structure on Fractional Order Coupled Neural Networks with Linear Coupling Delay: A Robust Synchronization Problem

This sequel is concerned with the analysis of robust synchronization for a multi-weighted complex structure on fractional-order coupled neural networks (MWCFCNNs) with linear coupling delays via state feedback controller. Firstly, by means of fractional order comparison principle, suitable Lyapunov method, Kronecker product technique, some famous inequality techniques about fractional order calculus and the basis of interval parameter method, two improved robust asymptotical synchronization analysis, both algebraic method and LMI method, respectively are established via state feedback controller. Secondly, when the parameter uncertainties are ignored, several synchronization criterion are also given to ensure the global asymptotical synchronization of considered MWCFCNNs. Moreover, two type of special cases for global asymptotical synchronization MWCFCNNs with and without linear coupling delays, respectively are investigated. Ultimately, the accuracy and feasibility of obtained synchronization criteria are supported by the given two numerical computer simulations.

     

Decentralized adaptive synchronization of an uncertain complex delayed dynamical network

In this paper, we investigate the locally and globally adaptive synchronization problem for an uncertain complex dynamical network with time-varying coupling delays based on the decentralized control. The coupling terms here are bounded by high-order polynomials with known gains that are ubiquitous in a large class of complex dynamical networks. We generalize the usual technology of searching for an appropriate coordinates transformation to change the network dynamics into a series of decoupled lower-dimensional systems. Several adaptive synchronization criteria are derived by constructing the Lyapunov-Krasovskii functional and Barbalat lemma, and the proposed criteria are simple in form and convenient for the practical engineering design. Numerical simulations illustrated by a nearest-neighbor coupling network verify the effectiveness of the proposed synchronization scheme.     

Robust one-time password authentication scheme using smart card for home network environment

Due to the exponential growth of the Internet users and wireless devices, interests on home networks have been enormously increased in recent days. In digital home networks, home services including remote access and control to home appliances as well as services offered by service providers are alluring. However, the remote control services cause digital home networks to have various security threats. Hence, for digital home networks, robust security services, especially remote user authentication, should be considered. This paper presents a robust and efficient authentication scheme based on strong-password approach to provide secure remote access in digital home network environments. The proposed scheme uses lightweight computation modules including hashed one-time password and hash-chaining technique along with low-cost smart card technology. It aims to satisfy several security requirements including stolen smart card attack and forward secrecy with lost smart card as well as functional requirements including no verification table and no time synchronization. Comparing with the existing representative schemes, it can be validated that the proposed scheme is more robust authentication mechanism having better security properties. We have conducted formal verification of the proposed scheme.     

Event-triggered synchronization control for complex networks with uncertain inner coupling

This paper is concerned with the event-triggered synchronization control problem for a class of complex networks with uncertain inner couplings. The uncertain inner coupling under consideration is characterized in terms of the interval matrix. In order to save the communication and computation resources, the event-based mechanism is adopted and the event-triggered synchronization control scheme is proposed for the complex networks. First, we transform the event-triggered synchronization control problem into the exponential stabilization problem for a new class of dynamical systems with multiple delays. Then, by employing the Lyapunov stability theory, we derive a sufficient condition under which the multi-delayed system is exponentially stable. Subsequently, a set of event-triggered synchronization controllers is designed in terms of the solution to a linear matrix inequality that can be solved effectively by using available software. Finally, a numerical simulation example is presented to show the effectiveness of the proposed event-triggered control scheme.     

统一混沌系统的混沌观测器同步控制及其应用

根据连续时间混沌系统可由单变量及其导数重构相空间的原理,采用混沌观测器同步方法.研究了统一混沌系统的同步控制问题.基于连续系统的稳定性准则,提出了统一混沌系统的混沌观测器同步定理.将该同步方法应用于保密通信,设计了基于时分复用的混沌掩盖保密通信新方案,并对该方案的保密性能进行了分析.基于MATLAB的数值仿真结果证明了同步控制方法和保密通信方案的有效性.     

Pinning synchronization of complex delayed dynamical networks via generalized intermittent adaptive control strategy

In this paper, the problem of pinning synchronization for delayed complex directed networks via generalized intermittent adaptive control strategy is considered. First, a dynamical mode of delayed network is investigated. Second, a generalized intermittent adaptive control strategy which unified the traditional periodic intermittent control and the aperiodic case is introduced. Additionally, by constructing a piecewise Lyapunov auxiliary function and making use of piecewise analysis technique, some effective and novel criteria to ensure the global synchronization of delayed complex networks based on the designed control protocols are obtained. Finally, an example with numerical simulations is provided to demonstrate the validness of the theoretical results proposed scheme.     

Set stability of controlled Chua’s circuit under a non-smooth controller with the absolute value

Chua’s circuit is a typical system with the piecewise-smooth vector field via the absolute value. A new piecewise-linear feedback control scheme with the absolute value is introduced to realize stabilization of sets of the controlled Chua’s circuit. The equilibrium sets and the global asymptotical stability with respect to several invariant sets, which may consist of both admissible and boundary equilibrium points or equilibrium manifolds, are investigated for the controlled Chua’s circuit system. The non-smooth controller has a simple structure and available control properties, and it is easy to be applied in engineering practice. It is shown by numerical simulations that this controller can effectively realize chaos control and stabilization of equilibrium states.