Stability of stochastic switched epidemic systems with discrete or distributed time delay

Stochastic switched epidemic systems with a discrete or distributed time delay are constructed and investigated. By the Lyapunov method and lto＇s differential rule, the existence and uniqueness of global positive solution of each system is proved. And stability conditions of the disease-free equilibrium of the systems are obtained. Numerical simulations are presented to illustrate the results.     

一类分布参数混合系统的稳定性分析

将混合系统推广到分布参数环境下,提出分布参数混合系统的概念.基于混合系统和分布参数系统的建模方法,建立了一类分布参数混合系统的模型,并对其稳定性进行分析.运用算子半群理论以及混合系统的五元组描述法及其稳定性关系比较理论的结论,通过选择适当的映射,将分布参数混合系统的的稳定性问题转化为集中参数下混合系统稳定性问题,进而得出了一致渐近稳定的充分条件并加以证明.仿真实例验证了文中结论的正确性.     

Adaptive NN stabilization for stochastic systems with discrete and distributed time-varying delays

A new adaptive neural network(NN) output-feedback stabilization controller is investigated for a class of uncertain stochastic nonlinear strict-feedback systems with discrete and distributed time-varying delays and unknown nonlinear functions in both drift and diffusion terms.First,an extensional stability notion and the related criterion are introduced.Then,a nonlinear observer to estimate the unmeasurable states is designed,and a systematic backstepping procedure to design an adaptive NN output-feedback controller is proposed such that the closed-loop system is stable in probability.The effectiveness of the proposed control scheme is demonstrated via a numerical example.     

New criteria on delayed state feedback stabilization for stochastic systems with time-varying delay

The problems of robust exponential stability in mean square and delayed state feedback stabilization for uncertain stochastic systems with time-varying delay are studied.By using Jensen’s integral inequality and combining with the free weighting matrix approach,new delay-dependent stability conditions and delayed state feedback stabilization criteria are obtained in terms of linear matrix inequalities.Meanwhile,the proposed delayed state feedback stabilization criteria are more convenient in application than the existing ones since fewer tuning parameters are involved.Numerical examples are given to illustrate the effectiveness of the proposed methods.     

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.     

Delay-dependent exponential stability of impulsive stochastic systems with time-varying delay

The problem of delay-dependent exponential stability is investigated for impulsive stochastic systems with time-varying delay.Although the exponential stability of impulsive stochastic delay systems has been discussed by several authors,few works have been done on delay-dependent exponential stability of impulsive stochastic delay systems.Firstly,the Lyapunov-Krasovskii functional method combing the free-weighting matrix approach is applied to investigate this problem.Some delay-dependent mean square exponential stability criteria are derived in terms of linear matrix inequalities.In particular,the estimate of the exponential convergence rate is also provided,which depends on system parameters and impulsive effects.The obtained results show that the system will stable if the impulses’ frequency and amplitude are suitably related to the increase or decrease of the continuous flows,and impulses may be used as controllers to stabilize the underlying stochastic system.Numerical examples are given to show the effectiveness of the results.     

离散时间修理延迟单部件可修系统的可靠性分析

针对离散时间下修理有延迟的单部件可修系统,建立了系统状态转移的数学模型。该模型假定系统有正常、维修和故障后待修三种状态,并且系统寿命、修复时间和等待修理时间均遵从一般离散分布。利用随机过程的方法,研究了该可修系统状态之间的转移关系。在该模型的基础上得到了系统可靠度、可用度、平均故障次数等常用可靠性指标。最后,通过一组算例来说明了该模型的有效性。     

Perturbation and robust controllability of singular distributed parameter control systems in Hilbert space

Perturbation and robust controllability of the singular distributed parameter control system are discussed via functional analysis and the theory of GE-semigroup in Hilbert space.The perturbation principle of GE-semigroup and the sufficient condition concerning the robust controllability of the singular distributed parameter control system are obtained,in which the controllability for singular distributed parameter control system is not destroyed,if we perturb the equation by small bounded linear operator.     

Adaptive neural control for a class of uncertain stochastic nonlinear systems with dead-zone

The problem of adaptive stabilization is addressed for a class of uncertain stochastic nonlinear strict-feedback systems with both unknown dead-zone and unknown gain functions.By using the backstepping method and neural network(NN) parameterization,a novel adaptive neural control scheme which contains fewer learning parameters is developed to solve the stabilization problem of such systems.Meanwhile,stability analysis is presented to guarantee that all the error variables are semi-globally uniformly ultimately bounded with desired probability in a compact set.The effectiveness of the proposed design is illustrated by simulation results.     

Exponential estimates for stochastic delay equations with norm-bounded uncertainties

This paper presents the sufficient conditions for the exponential stability of linear or semilinear stochastic delay equations with time-varying norm bounded parameter uncertainties. Exponential estimates for the solutions are also obtained by using a modified Lyapunov-Krasovski functional. These conditions can be tested numerically using interior point algorithms. This work is Supported by the National Natural Science Foundation of China under Grant Nos. 10801056 and 10826095.     

离散时间分布参数系统的模型逼近预测控制

提出了离散时间分布参数系统的一种预测控制方法。该方法采用广义正交多项式对分布参数系统的模型进行逼近,将离散时间分布参数系统的预测控制问题转化为集中参数系统的预测控制问题,运用模型算法控制方法对集中参数系统进行预测控制,求出控制律,经反演变换得出分布参数系统的预测控制。给出了该方法的具体步骤,仿真示例表明了方法的有效性。     

连续分布时滞抛物型系统的全局指数稳定性

基于比较原理,利用推广的向量Hanalay微分不等式、Dini导数,结合Green公式及不等式分析技术,研究几类连续分布时滞的抛物型控制系统所导出的滑动模运动方程的全局指数稳定性问题。在仅要求系统的系数矩阵是个M 矩阵的条件下,证明了所获得的滑动模运动方程是全局指数稳定性的,建立了滑动模运动方程全局指数稳定性定理。并为研究连续分布时滞的抛物型系统的变结构控制问题奠定了基础。     

分布式系统中的元挖掘研究

针对分布式系统中的数据挖掘问题,提出了一种新颖高效的分布式元挖掘方法。该算法只需在各自站点扫描局部数据库两次即可形成局部和全局频繁项集,并根据局部和全局频繁项集形成相应的关联规则集及元规则集。在形成元规则集时无需扫描各站点中的关联规则集,这样既减少了分布式系统中需要的通信交换的数据量,也减少了各站点中的扫描数据量。研究表明所提出的算法是有效的。     

On passivity of state delayed stochastic jump systems

1.INTRODUCTION Stochasticjumpsystemisaspecialkindofhybridsys tems.Itisdescribedbyacontinuous timefinite state Markovprocesswhichreferstothemode,andbya dynamicsystemofdifferentialequationswhichrefers tothestate.Thejumpsystemscanmodelthedynam icsystemssubjecttoabruptvariationintheirstruc turesandthereforattractresearchinterestinginthe world.Recently,thereweresomeresearchesoncon trolproblemsforjumpsystemswithtimedelay[1,2].Passivityplaysanimportantroleinsystemand controltheory.Butalmostallr…     

分布式飞行仿真系统中的参数分布技术

详细研究了基于共享内存机制的分布式飞行仿真系统中仿真模块发布或定购参数时应该遵循的参数声明原则，并分析了仿真系统的参数发布区、参数定购区以及自定购区的构成与特点，最后给 各参数区的生成算法和一个简单易懂的例子。结合这些技术方法，并采用共享内存机制可以实现飞行仿真系统模块参数在节点间透明共享，从而可以实现分布式飞行仿真应用。     

基于邻接度量函数的β算法

复合随机计算系统的研究目前已成为组合优化等优化与搜索问题的重要研究方向，在阐述复合随机计算系统的一般形式的基础上，提出了处理组合优化问题的基于邻接度函数的β算法，证明了相关的性质，并以实例阐述了该方法的具体运用。     

加工时间为连续随机变量的Job Shop调度问题

针对实际调度问题中存在的不确定现象,提出了加工时间服从正态分布、最大完成时间的期望值作为目标函数的随机Job Shop问题;然后提出了解决该问题的智能优化算法:采用随机模拟的方式产生输入输出数据,利用遗传算法训练神经网络,将训练过的神经网络嵌入到另一遗传算法中,用该遗传算法来优化Job Shop调度问题;最后给出了仿真实验,通过仿真实验证明,该算法对于解决加工时间为随机变量的Job Shop调度问题是行之有效的。     

分布交互式战斗机空战仿真系统的开发

简要介绍了一种实时分布交互式战斗机空战仿真系统的开发。整个系统按照分层模块思想设计,对空战中战斗机关键子系统和关键行为进行了精确的数学建模,减少了建模的复杂度、保持了平台的开放性和可维护性,据此实现了局域网环境下的分布交互式空战仿真研究。初步的仿真结果表明系统具有实时、精确、高逼真度、高效费比的特点,可作为飞机设计和空战研究的重要辅助手段。     

基于FLUENT/MATLAB接口的分布参数系统闭环控制仿真

在工程实际中常遇到的流动、传热和燃烧等问题中,大都为分布参数系统.针对该分布参数模型建模难的问题,结合CFD仿真软件FLUENT和系统仿真软件MATLAB各自的优点,根据WinSock网络通信原理,开发了FLUENT/MATLAB接口,建立了分布参数模型闭环控制快速原型的仿真平台,并且通过算例仿真验证了该方法的可行性与实用性.