不同节点动态的复杂网络外部同步牵制控制

研究节点动态不同的两个复杂网络的外部同步问题。运用牵制控制方法,网络模型选取节点输出线性耦合模型,基于输出控制思想,设计结构简单的牵制控制器,对响应网络中的部分节点施加输出反馈控制,使得两个复杂动态网络达到外部同步,即实现响应网络与驱动网络的渐近同步。根据李雅普诺夫稳定性理论,推出相应的同步准则,得到控制器参数选择条件。仿真时,驱动网络和响应网络分别选取Lorenz系统和Lü系统,对全局耦合网络和最近邻耦合网络两个典型网络拓扑进行仿真,验证了所提方法的有效性。     

不同节点动态的复杂网络外部同步牵制控制

研究节点动态不同的两个复杂网络的外部同步问题。运用牵制控制方法,网络模型选取节点输出线性耦合模型,基于输出控制思想,设计结构简单的牵制控制器,对响应网络中的部分节点施加输出反馈控制,使得两个复杂动态网络达到外部同步,即实现响应网络与驱动网络的渐近同步。根据李雅普诺夫稳定性理论,推出相应的同步准则,得到控制器参数选择条件。仿真时,驱动网络和响应网络分别选取Lorenz系统和Lu系统,对全局耦合网络和最近邻耦合网络两个典型网络拓扑进行仿真,验证了所提方法的有效性。     

基于单向耦合法的不确定复杂网络间有限时间同步

针对具有不确定性的复杂网络有限时间同步问题, 提出一种新颖的单向耦合控制方法. 构建含有未知参量及未知拓扑结构的驱动?响应复杂网络模型, 考虑两个网络具有不同的节点数, 同时受到时变耦合时滞的影响, 并且网络内部分别具有不同的节点系统. 基于有限时间稳定性理论和线性矩阵不等式变换, 通过在响应网络中引入单向耦合项, 实现两个网络间的有限时间同步, 同时准确辨识未知参量及未知拓扑结构. 仿真实验验证所提同步方法的有效性, 对比实验结果表明所提方法在减少耦合数量的同时具有更快的同步速率及更小的波动范围.     

一种基于局部特性的重要邮箱用户发现方法

针对有向赋权邮件网络,提出一种基于局部特性的重要邮箱用户发现算法。该方法考虑了节点的点权对节点重要度评估的影响,紧密结合邮件网络的特性,给出了点权的新定义。同时,为了应用于大型有向赋权复杂网络,提出依据网络中节点的局部特征的节点的重要性度量算法,该算法的时间复杂度为ο(2m+n)。在安然邮件语料库上验证了该方法,并且得到了较好的实验结果。     

带有未知参数的驱动-响应网络的自适应同步

研究由带有未知参数的混沌系统作为节点动力学构成的驱动-响应网络的自适应同步.基于Lyapunov稳定性理论以及LaSalle不变原理,设计合适的控制器和参数更新规则,使得驱动系统与响应网络达到同步.为了验证理论的正确性,选择加权网络和BA无标度网络作为数值例子,并比较相同网络结构下不同的节点动力学对同步时间的影响.数值...     

具有量化脉冲效应的时滞混杂动态网络同步分析

研究了具有量化脉冲效应的时滞混杂动态网络的同步动力学,利用偏收缩理论和矩阵测度概念,并结合量化器的特征,提出了网络节点实现同步的一般性条件.与以往大多数基于Lyapunov稳定性方法所提出的结果不同,利用本文的方法可以消除单个节点和网络耦合中的非线性函数的限制性假设,从而降低保守性.本文突出的特征就是综合了网络节点和耦合拓扑中的多重时滞影响和脉冲行为,并且考虑了脉冲效应在网络传输中的有限通信能力问题,具有实际意义.最后,通过对Lorenz混沌系统作为网络节点的混杂动态网络进行数值模拟,验证了所得结果的有效性.     

节点非线性耦合的复杂动态网络同步控制研究

文中研究节点状态非线性耦合的复杂动态网络的局部同步和全局同步的问题.不同于现有的这类网络的利用节点状态变量设计控制器进行同步控制的方法,提出了一种设计同步控制器的新方法,该方法只需利用网络节点输出变量构造控制器,使其达到同步,克服了现有方法利用节点状态变量设计控制器存在的不足,使控制器实现起来更加简单.利用 Lyapunov 方法给出这类复杂网络的同步准则,以 Lorenz 混沌映射作为复杂网络的节点进行数值仿真,研究表明,这种方法能够使节点状态非线性耦合的复杂动态网络达到同步,通过系统仿真,证明了文中所提方法的有效性     

复杂软件的级联故障建模

软件复杂性的增加直接导致软件故障的复杂性增加.从系统科学的角度出发,采用复杂网络等方法和技术在整体上研究复杂软件的级联故障特性是研究软件质量的一个新视角.以函数为节点、以调用关系为边,提出了使用有向边和边权表述函数间的调用关系和紧密程度的拓扑模型.通过引入函数容错能力和软件故障强度建立复杂软件的级联故障模型,模拟软件运...     

具有相似节点的耦合时滞复杂网络的稳定性与同步控制分析

讨论具有相似节点的耦合时滞复杂网络的稳定和同步问题,且网络模型的外部耦合满足耗散条件.对于不同维数节点的复杂网络,根据节点之间相似参量的信息,利用线性矩阵不等式方法设计出含有相似参量的分散控制器,给出耦合复杂网络实现稳定的时滞独立判定准则.定义了含有相似参量的同步流形的概念,并设计了相应的分散控制器,给出了能使整个复杂网络同步的时滞独立判定条件.数值算例表明了所提出设计方法的有效性.     

一类自同步时变耗散耦合网络内耦合矩阵选择方法

研究使一类时变耗散耦合复杂网络自同步的内耦合矩阵选择方法.在主稳定函数法的基础上,通过对节点变分方程系统阵的约当标准型进行分析,给出了几种适用于不同情况的内耦合矩阵选择方法,以同步速度为依据提出了较优内耦合矩阵的选择命题,并给出了相应的选择方法.最后以3个典型算例验证了所提出方法的有效性.     

多链接复杂网络指数同步的间歇事件触发控制

本文研究了基于间歇事件触发控制策略的延迟多链接复杂网络的指数同步问题, 设计了一种间歇动态事 件触发控制策略. 相比于间歇静态事件触发控制策略, 本文提出的控制策略是基于控制区间内的动态事件触发, 极 大地减少了事件触发次. 并且, 考虑的间歇控制的控制增益是自适应的, 这具有动态调整的作用. 基于图论和李雅 普诺夫方法, 本文给出了实现延迟多链接复杂网络指数同步的充分条件. 此外, 本文设计的控制策略能够排除Zeno 现象. 并且, 将理论结果应用于一类振子系统的指数同步问题. 最后, 文章给出相应的数值仿真来验证理论结果的有 效性和可行性.     

Finite-time Function Projective Synchronization in Complex Multi-links Networks and Application to Chua’s Circuit

International Journal of Control, Automation and Systems - The article focuses on the problem of finite-time function projective synchronization which is happened in complex multi-links networks...     

Further results for synchronization of two coupled Boolean networks

This paper investigates the complete synchronization of drive-response Boolean networks (BNs ) using the semi-tensor product of matrices. First, a necessary and sufficient condition for complete synchronization is obtained. Next, a pinning control method for achieving complete synchronization of drive-response BNs is proposed, based on certain transformations of the state transition matrix of drive BN . Then, an algorithm is proposed to obtain the minimum number of pinning nodes, based on the perturbation method. Finally, two numerical examples are given to verify the validity of the study results.     

Exponential synchronization of a class of neural networks with time-varying delays.

This paper aims to present a synchronization scheme for a class of delayed neural networks, which covers the Hopfield neural networks and cellular neural networks with time-varying delays. A feedback control gain matrix is derived to achieve the exponential synchronization of the drive-response structure of neural networks by using the Lyapunov stability theory, and its exponential synchronization condition can be verified if a certain Hamiltonian matrix with no eigenvalues on the imaginary axis. This condition can avoid solving an algebraic Riccati equation. Both the cellular neural networks and Hopfield neural networks with time-varying delays are given as examples for illustration.     

On the complexity of vertex-disjoint length-restricted path problems

Let $G=(V,E)$ be a simple graph and $s$ and $t$ be two distinct vertices of $G$. A path in $G$ is called \lb for some $\length\in\N$ if it does not contain more than $\length$ edges. We prove that computing the maximum number of \vd \lb $s,t$-paths is \apx--complete for any $\length\geq 5$. This implies that the problem of finding $k$ \vd \lb $s,t$-paths with minimal total weight for a given number $k\in\N$, $1\leq k \leq |V|-1$, and nonnegative weights on the edges of $G$ is \npo--complete for any length bound $\length\geq 5$. Furthermore, we show that these results are tight in the sense that for $\length\leq 4$ both problems are polynomially solvable, assuming that the weights satisfy a generalized triangle inequality in the weighted problem. Similar results are obtained for the analogous problems with path lengths equal to \length instead of at most \length and with edge-disjointness instead of vertex-disjointness.     

Consecutive Synchronization of a Delayed Complex Dynamical Network via Distributed Adaptive Control Approach

In this paper, a consecutive synchronization scheme is investigated to synchronize the nodes of a delayed complex dynamical network with an isolated node via an adaptive control approach. The specific feature of this scheme consists in the structure of the communication links: a communication connection is required between the isolated node and one selected node in the network, and further communication links exist between any node and one neighbor node. In this way, all nodes are connected together like a chain. Based on Lyapunov-Krasovskii theory, some conditions are obtained in the form of linear matrix inequalities to guarantee the consecutive synchronization by the designed distributed adaptive control. To make this synchronization scheme more practical, no constraints have been considered for coupling connection matrix such as being symmetric or zero row sum. Finally, a numerical example is presented to demonstrate the effectiveness of the proposed method.     

On pinning synchronization of complex dynamical networks

There exist some fundamental and yet challenging problems in pinning control of complex networks: (1) What types of pinning schemes may be chosen for a given complex network to realize synchronization? (2) What kinds of controllers may be designed to ensure the network synchronization? (3) How large should the coupling strength be used in a given complex network to achieve synchronization? This paper addresses these technique questions. Surprisingly, it is found that a network under a typical framework can realize synchronization subject to any linear feedback pinning scheme by using adaptive tuning of the coupling strength. In addition, it is found that the nodes with low degrees should be pinned first when the coupling strength is small, which is contrary to the common view that the most-highly-connected nodes should be pinned first. Furthermore, it is interesting to find that the derived pinning condition with controllers given in a high-dimensional setting can be reduced to a low-dimensional condition without the pinning controllers involved. Finally, simulation examples of scale-free networks are given to verify the theoretical results.     

矿用分布式采集系统时钟同步方案设计与实现

单一的时钟同步技术由于其精度及应用局限性,无法满足矿用分布式采集系统高精度、高可靠性的时钟同步性能要求。针对上述问题,提出了基于北斗+IEEE 1588V2+本地后备时钟的三级协同时钟同步方案。选用部署在地面的T600-BDGOCXC型北斗授时服务器作为主时钟,为系统提供纳秒级精度的绝对时钟;采用STM32F407+DP83848及PTPd协议栈实现支持IEEE 1588V2协议的采集节点,通过井下工业环网将北斗的绝对时钟同步到各采集节点;本地后备时钟采用STM32F407内部RTC(实时时钟)实现,给各采集节点提供秒级精度的时间戳初值,便于各采集节点用最短时间实现与主时钟的同步。测试结果表明,北斗授时服务器与采集节点通过交换机直连的情况下,1 min后时钟同步精度达162 ns;北斗授时服务器与采集节点通过三级交换机连接的情况下,时钟同步精度为565 ns;在北斗授时服务器失效的情况下,优先级高的采集节点升级为主时钟并为其余采集节点授时,具有较强的可靠性。