Passivity analysis for uncertain stochastic neural networks with discrete interval and distributed time-varying delays

The problem of passivity analysis is investigated for uncertain stochastic neural networks with discrete interval and distributed time-varying delays. The parameter uncertainties are assumed to be norm bounded and the delay is assumed to be time-varying and belongs to a given interval, which means that the lower and upper bounds of interval time-varying delays are available. By constructing proper Lyapunov-Krasovskii functional and employing a combination of the free-weighting matrix method and stochastic analysis technique, new delay dependent passivity conditions are derived in terms of linear matrix inequalities (LMIs). Finally, numerical examples are given to show the less conservatism of the proposed conditions.     

区间时滞相关不确定奇异系统的鲁棒稳定性和镇定性

研究区间时滞相关的不确定时变时滞奇异系统的鲁棒稳定性和镇定性问题,不确定参数假设是范数有界的。充分利用时滞的下界信息构造Lyapunov函数,用严格的矩阵不等式给出系统对所有的容许不确定满足正则、无脉冲、稳定的新判据。基于这个判据,设计状态反馈控制器使得系统鲁棒稳定。数值例子说明所得结果具有更小的保守性。     

On delay-dependent robust stability for uncertain neutral systems

1.INTRODUCTION Time delaysarefrequentlyencounteredinvariousengi neeringsystems,includingaircraftstabilization,nuclear reactors,populationdynamicsmodels[1].Theirexistence isoftenthesourceofinstabilityinmanycontrolsystems.Stabilitycriteriafortime delaysystemscanbeclassified intotwocategories.Thestabilitycriteriathatincludein formationonthesizeofdelaysarereferredtoasdelay de pendentcriteria[2～18]andthecriteriaapplicabletoanar bitrarysizeofdelaysarereferredtoasdelay independent criteria[19～…     

Mean-square exponential stability for stochastic time-varying delay systems with Markovian jumping parameters: a delay decomposition approach

The mean-square exponential stability problem is investigated for a class of stochastic time-varying delay systems with Markovian jumping parameters.By decomposing the delay interval into multiple equidistant subintervals,a new delay-dependent and decay-rate-dependent criterion is presented based on constructing a novel Lyapunov functional and employing stochastic analysis technique.Besides,the decay rate has no conventional constraint and can be selected according to different practical conditions.Finally,two numerical examples are provided to show that the obtained result has less conservatism than some existing ones in the literature.     

New Lyapunov-Krasovskii Functional for Stability Analysis of Linear Systems with Time-Varying Delay

This paper focuses on the problem of delay-dependent stability of linear systems with time-varying delay. A new delay-product-type augmented Lyapunov-Krasovskii functional(LKF) is constructed. Based on the LKF and by employing a generalized free-matrix-based integral inequality,less conservative delay-dependent stability criteria are obtained. Finally, two well-known numerical examples are used to confirm the effectiveness and the superiority of the presented stability criteria.     

基于离散正则模型的时变信道盲辨识算法

以CDMA时变信道离散正则模型为基础,提出了基于改进的矩阵外积分解的时变信道盲辨识算法。算法对传统的矩阵外积分解算法进行修正,使其适应离散正则模型两级盲辨识,并引入了精确的时延阶数估计,克服了现有算法需要预先知道信道时延实际阶数的局限,使其在仅知道信道阶数上界的条件下完成盲辨识。仿真结果表明了该算法的有效性。     

时滞细胞神经网络的全局渐近鲁棒稳定性分析

针对一类具有时滞的细胞神经网络系统,利用新的Lyapunov Krasovskii函数,给出了系统全局渐近鲁棒稳定的时滞相关稳定性条件。其结果以线性矩阵不等式的形式给出,可以很容易求出系统稳定的时滞上界。进而可以很容易得到时滞无关稳定性结果,且该结果包含了现有文献中许多关于时滞无关稳定性分析的结果。数值算例说明了结论的有效性。     

Global Exponential Stability of Variable Delay and Time－varying Measure Differential Systems with Impulse Effect

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变时滞广义神经网络的指数稳定性

讨论具有可变时滞的Cohen Grossberg广义神经网络平衡态的稳定性问题。以推广的Halanay微分不等式为工具,通过构造合适的Lyapunov函数,结合Dini导数和不等式技巧,对具有可变时滞(适合于任何时滞有界情况)的广义神经网络平衡态的指数稳定性进行分析。在适当的假设条件下,得到了系统渐近指数稳定的几个充分性判据,与此同时也给出了相应的Lyapunov指数。     

考虑时延与丢包的网络控制系统分析与综合

针对具有时变网络诱导时延和丢包问题的网络控制系统稳定性分析与控制器设计问题,通过考虑网络诱导时延是时变和有界的情形,并分析网络诱导时延与其上界之间的关系,应用Lyapunov-Krasovskii泛函结合积分不等式方法,提出了一种改进的、同时考虑了网络诱导时延和丢包问题的网络控制系统稳定条件,并基于改进的锥补线性化迭代算法（improved cone complementary linearization, ICCL）给出了一种具有更低保守性的控制器设计方法。数值实例表明上述方法的有效性。     

离散动态系统稳定与不稳定的简捷判据

运用矩阵特征值分析技巧研究了区间矩阵及一类离散动态系统的稳定性问题。在无需任何附加条件的情况下,仅用区间矩阵的界阵元素给出了一般区间矩阵及离散动态系统混合稳定、渐进(离散)稳定与不稳定的简便代数判据(含充分条件、必要条件与充要条件),弃掉了对区间矩阵的下(上)界阵为非负(正)的条件要求。相对于现存结果,提出判据不仅明显具有普适性强实用范围广且保守性小的特性,而且还涵盖了一些原有的稳定性判据。     

Controllability of General Linear Discrete Multi-Agent Systems with Directed and Weighted Signed Network

This paper investigates the controllability of general linear discrete-time multi-agent systems with directed and weighted signed networks by using graphic and algebraic methods. The non-delay and delay cases are considered respectively. For the case of no time delay, the upper bound condition of the controllable subspace is given by using the equitable partition method, and the influence of coefficient matrix selection of individual dynamics is illustrated. For the case of single delay and multiple delays, the equitable partition method is extended to deal with time-delay systems, and some conclusions are obtained. In particular, some simplified algebraic criteria for controllability of systems with time delay are obtained by using augmented system method and traditional algebraic controllability criteria.

     

重标极差方法下时变Hurst指数的构建和实证研究

在时间序列的重标极差分析方法的基础上,定义了一个时变Hurst指数的概念,推导并证明了时变Hurst指数的2条性质,并引入滑动分块自助法计算Hurst指数的标准差.以此为基础,用Hurst指数的下限及随机过程服从随机游走时的Hurst的上限作为分析工具,对Hurst指数能否成功预测市场的反转进行了研究.实证研究表明:时变Hurst指数能成功地预测市场的反转.     

区间变时滞不确定系统鲁棒稳定性分析

研究了一类线性区间变时滞不确定系统鲁棒稳定性问题。基于新型的时滞分割法和交互式凸组合技术,借助于构造包含四重积分项的新Lyapunov Krasovskii泛函,并利用新的积分不等式界定方法给出了线性矩阵不等式形式的时滞相关稳定性判据。与已有文献相比,该判据扩大了保证系统稳定的最大时滞上界范围,在降低结论的保守性和提高计算效率两者间达到了一个很好的平衡。最后通过3个具有代表性的数值例子对比验证了该方法在降低结论保守性方面的优越性。     

Sampled-Data H∞ Dynamic Output Feedback Controller Design for Fuzzy Markovian Jump Systems

This paper considers the issue of H_∞ dynamic output feedback controller design for T-S fuzzy Markovian jump systems under time-varying sampling with known upper bound on the sampling intervals. The main aim is to realize sampled-data fuzzy dynamic output feedback control so as to demonstrate the stochastic stability and H_∞ performance index of the closed-loop sampled-data fuzzy Markovian jump systems. Then, by making the most of the information within the sampling interval,...     

基于时滞分割法的Markov随机切换系统指数稳定性

研究了时变时滞满足h₁≤d(t)≤h₂的Itô型随机Markov切换系统的区间时滞相关指数稳定性。基于时滞分割的思想,建立了新颖的Lyapunov-Krasovskii泛函,并引入一些改进的积分等式,以线性矩阵不等式的形式给出了低保守性的区间时滞相关指数稳定条件。最后用几个数值算例说明该结论的有效性及其较低的保守性。     

Novel Criteria for Exponential Stability of Linear Non-Autonomous Functional Differential Equations

General linear non-autonomous functional differential equations are considered. Explicit criteria for exponential stability are given. Furthermore, the authors present an explicit robust stability bound for systems subject to time-varying perturbations. Two examples are given to illustrate the obtained results.     

具有无界时变时滞的线性系统的稳定性

讨论了一类无界时变时滞线性系统的稳定性，给出了无界时变时滞线性系统稳定性的充分条件，这些条件也适用于常时滞系统。同时讨论了具有多个无界时变时滞系统的稳定性，并且改进了一些已有的关于常时滞系统稳定性的结论。最后给出了本文结论的两个示例。     

Ho∞-based fault detection for nonlinear networked systems with random packet dropout and probabilistic interval delay

The fault detection problem for the nonlinear networked control system (NCS) with packet dropout and delay is investigated.A nonlinear stochastic system model is proposed to account for the NCS with random packet dropout and networkinduced non-uniformly distributed time-varying delay in both from sensor to controller (S/C) and from controller to actuator (C/A).Based on the obtained NCS model,employing an observer-based fault detection filter as the residual generator,the addressed fault detection problem is converted into an auxiliary nonlinear H∞ control problem.Then,with the help of Lyapunov functional approach,a sufficient condition for the desired fault detection filter is constructed in terms of certain linear matrix inequalities,which depend on not only the delay interval but also the delay interval occurrence rate and successful packet communication rate.Especially,a trade-off phenomenon between the maximum allowable delay bound and successful data packet transmission rate is found,which is typically resulted from the limited bandwidth of communication networks.The effectiveness of the proposed method is demonstrated by a simulation example.