基于交换式VLAN技术的校园网建设中的应用

针对校园网网络响应率较低的问题,笔者提出了基于交换式VLAN技术的校园网建设。根据对校园网建设的需求分析,笔者将校园网按照功能区对子网进行合理划分,通过对交换式VLAN ID的规划,有效避免了校园网IP地址冲突的发生,运用交换式VLAN技术对校园网地址进行动态分配,可以实现交换式VLAN技术在校园网建设中的应用。实验证明,基于交换式VLAN技术的校园网具有较高的网络响应率。     

基于OPNET的交换式以太网实时性仿真分析

以太网的通信不确定性是其应用于实时性要求较高的工业控制系统中的障碍.交换式以太网的出现使这一问题得到了改善.研究了传统以太网和交换式以太网的网络时延问题,根据网络中央节点设备的不同,通过构建工业以太网模型,研究不同负载下网络的性能仿真结果表明了交换式以太网良好的实时性能.     

企业网中的多层交换

性能与控制相结合是为企业带来竞争优势的网络的中心环节,可满足性能和控制双重要求的交换式路由器引起了人们极大的兴趣,本文对交换式路由器的主要功能及其在设计企业网络中的重要意义作了深入分析。     

基于交换式以太网的网络并行计算系统中通信性能的分析与测试

网络通信性能是影响网络并行计算的重要原因，而交换式网络的出现有助于改变这状况。本文定量地分析了基于交换式以太网的网络并行计算系统中的端到端通信和多目的发送两种通信方式的通信性能，并对一个典型的并行计算实例──并行距阵乘法进行了性能评测。通过与基于共享式以太网的网络并行计算系统中测试结果的对比，我们可以看出交换式以太网对改进网络并行计算性能的重要作用。     

基于网络演算的交换式以太网实时特性分析

交换式以太网在网络控制系统中的应用关键问题是实时能力,为此采用一种新型实时性能分析工具——网络演算,对交换式以太网实时能力进行确定性的分析和研究。针对FIFO调度算法,对两级树型拓扑结构的交换式以太网系统建立了通信模型,推导出各网络元素的到达曲线和服务曲线,由此得到了最大时延、所需缓冲区大小、输出突发量等实时业务流的主要参数解析表达式;利用推导所得结论计算了实时业务流的最大网络时延。     

交换式网络结构设计

在现代网络技术上,交换式网络是当前国际网络技术发展的重点,也是网络技术发展的热点。 交换式网络的核心设备是网络交换机(Switch),也可称为交换式集线器(Switch HUB),一般较大型的交换式网络设备称为网络交换机,而较小型的网络交换设备称为交换式集线器,通称为Switch。这种网络设备有固定式的,例如 3Com公司的系列产品Linkswitch,价格便宜、功能简单,主要可用于小型网络系统之中或原有的小型网络系统改造;也有插卡     

对交换局域网中ＳＭＯＮ监控技术的研究

阐述网络监控在网络管理中的重要性,讨论ＲＭＯＮ在交换式网络中的限制,并对SＯＭＮ在局域网中监控的解决方案作了相应的研究。     

基于交换式Ethernet的虚拟仪器网络测试技术研究

本文深入研究了基于交换式Ethernet的虚拟仪器网络测试技术．对交换式Ethernet和基于交换式Ethernet的网络测试系统做了详细的分析，并阐述了对该系统的网络功能实现。     

基于交换以太网的网络并行计算系统中通信性能的分析与测试

网络通信性能是影响网络并行计算的重要原因，而交换式网络的出现有助于改变这状况，本定量地分析了基于交换式以太网的网络并行计算系统中的端到端通信和多目的发送两种通信方式的通信性能。并对一个典型的并行计算实例－－并行距阵乘法进行了性能评测。通过与基于共享式以太网的网络并行计算系统中测试结果的对比，我们可以看出交换式以太网对改进网络并行计算性能的重要作用。     

交换式虚拟网络技术与模型

该文介绍了交换式局域网的虚拟网络技术,及交换式虚拟网络的几种模型。     

Stabilization of a class of switched nonlinear systems

The stabilization of a class of switched nonlinear systems is investigated in the paper. The systems concerned are of （generalized） switched Byrnes-Isidori canonical form, which has all switched models in （generalized） Byrnes- Isidori canonical form. First, a stability result of switched systems is obtained. Then it is used to solve the stabilization problem of the switched nonlinear control systems. In addition, necessary and sufficient conditions are obtained for a switched affine nonlinear system to be feedback equivalent to （generalized） switched Byrnes-Isidori canonical systems are presented. Finally, as an application the stability of switched lorenz systems is investigated.     

Stabilization of a class of switched nonlinear systems

The stabilization of a class of switched nonlinear systems is investigated in the paper. The systems con- cerned are of (generalized) switched Byrnes-Isidori canonical form, which has all switched models in (generalized) Byrnes- Isidori canonical form. First, a stability result of switched systems is obtained. Then it is used to solve the stabilization prob- lem of the switched nonlinear control systems. In addition, necessary and sufficient conditions are obtained for a switched affine nonlinear system to be feedback equivalent to (generalized) switched Byrnes-Isidori canonical systems are presented. Finally, as an application the stability of switched lorenz systems is investigated.     

Asymptotic switched composite adaptive control with application to robotic interaction tasks

This article proposes a new switched adaptive control design for uncertain switched systems with composite (time-driven and state-dependent) switching and shows its applicability in switched impedance control. A composite switched adaptive control design, consisting of the direct switched adaptive control and the indirect switched adaptive control counterpart, is developed to improve the control performance. Specifically, a new stability condition for composite switching is proposed by making use of differential matrix equations and Sylvester matrix equations, which are a generalization of Lyapunov matrix equations. The design results in a time-varying multiple Lyapunov function that is decreasing at the switching instants. From the theoretical point of view, the relevance of this work is the construction of the adaptive laws that guarantee asymptotic tracking error and asymptotic estimation for the direct and indirect switched adaptive control loops, respectively. From the practical point of view, the relevance of this work is validated in a new switched impedance control for the robot interaction with uncertain and discontinuous environments.     

Simultaneous state and output disturbance estimations for a class of switched linear systems with unknown inputs

The paper considers the issues of state estimation and output disturbance reconstruction for a class of switched linear systems with unknown inputs. A singular switched system is derived from the original switched system by taking the output disturbance as a part of a new extended state vector. For the constructed singular switched system, a robust sliding-mode switched observer which can not only estimate the states of original switched system but also reconstruct output disturbances is proposed, where the switching of the observer is synchronous with that of the switched system. A sufficient condition is provided to guarantee the existence of the switched observer by the feasibility of an optimisation problem with linear matrix inequality constraint, and the corresponding switching signal with average dwell time is designed such that the convergence of the estimation error system is proven to be exponential. Based on the state estimation of singular switched system, the methods of state estimation and output disturbance reconstruction of original switched system are proposed. Finally, the simulation results confirm the predicted performance of the proposed methods.     

Feedback passivation of switched nonlinear systems using storage-like functions

This paper addresses the issues of passivity and feedback passivation of switched nonlinear systems via multiple storage functions. The concept of storage-like functions for switched systems is presented. A sufficient condition for passivity of switched nonlinear systems is given via multiple storage functions under some switching signal. Then, the result is extended to find conditions under which a switched system is feedback equivalent to a passive switched system. Furthermore, passivity of switched cascade systems is investigated.     

State and fault estimation of sandwich systems with hysteresis

In this paper, a switched proportional integral observer (PIO) is designed for estimating the states and fault of sandwich systems with hysteresis. In the system, the actuator fault and sensor noise have been included simultaneously. The switched PIO contains a changeable transition matrix and a switched item, which can switch according to different working points of the hysteresis. The estimation errors of the states and fault are analyzed, and a theorem is given to illustrate the estimation errors of the states and fault, which are both bounded. The problem of selecting an appropriate feedback matrix of the switched PIO has been translated into an optimization problem with feedback matrix tuning. The effectiveness of the switched PIO has been testified in the simulation with a real application case. Moreover, to show the good performance of the switched PIO, a conventional PIO is proposed and compared in the simulation. The results show that the switched PIO is superior to the conventional one.     

A New Approach For Stability Analysis Of Time‐Dependent Switched Continuous‐Time Linear Systems

In this paper, a new approach for stability analysis of time‐dependent switched linear systems is proposed. System equivalence is the main idea in this new approach, which derives a switched discrete linear parameter‐varying system from the switched continuous‐time linear switched system with interval dwell time, and the stability properties of the two corresponding systems are proved to be equivalent. Then, by applying a quadratic Lyapunov function approach for the equivalent switched discrete system, the stability of the switched continuous‐time linear system can be established without checking any average dwell time condition. Finally the computation complexity is analyzed, and mode incidence matrix is introduced to reduce the computation cost.     

分布参数切换系统的稳定性分析

将切换系统的概念引入到分布参数系统中，提出分布参数切换系统的概念．结合切换系统和分布参数系统的建模方法，建立了两类分布参数切换系统的模型．运用切换系统的稳定性分析方法，对两类分布参数切换系统的稳定性进行分析，得出了指数稳定的充分条件．仿真示例验证了定理的正确性．     

一类周期切换控制稳定的算法设计

利用切换控制及凸组合弱化控制系统稳定性条件,使组合和满足Hurwitz条件而实现切换稳定。该文对切换系统的表达形式、切换信号及切换路径、切换收敛、稳定性判断准则及周期切换特征进行了分析。针对无扰动或扰动切换系统进行周期稳定性设计,提出3种切换控制率及对应的切换算法。通过对交通实例进行仿真设计,比对切换实验数据,反映出不同切换率稳定和收敛情况,通过上述算法实现系统的周期稳定。     

Model reference robust adaptive control for a class of uncertain switched linear systems

In this paper, we proposed a model reference robust adaptive control approach for a class of uncertain switched linear systems, in which subsystems of the switched linear system are in control canonical form. The control architecture is composed of a switched reference system (SRS) and a switched adaptive controller (SAC). The SRS specifies the desired dynamics of the uncertain switched linear system, while the SAC makes the uncertain switched linear system dynamics track the SRS dynamics. By multiple Lyapunov functions method, we prove that the closed‐loop switched system is uniformly bounded under arbitrary switching laws, provided that a linear matrix inequality (LMI)‐based sufficient condition is satisfied. We apply the proposed approach to a typical servo‐hydraulic positioning system. The simulation results show that the proposed approach is fairly insensitive to disturbances, uncertainties and non‐smoothly varying dynamics, and performs better than a proportional‐derivative controller or a minimal controller synthesis controller. Copyright © 2011 John Wiley & Sons, Ltd.