Exponential H∞ filtering for uncertain discrete‐time switched linear systems with average dwell time: A µ‐dependent approach

In this paper, the problem of exponential H_∞ filter problem for a class of discrete‐time polytopic uncertain switched linear systems with average dwell time switching is investigated. The exponential stability result of the general discrete‐time switched systems using a discontinuous piecewise Lyapunov function approach is first explored. Then, a new µ‐dependent approach is proposed, which means the analysis or synthesis of the underlying systems is dependent on the increase degree µ of the piecewise Lyapunov function at the switching instants. A mode‐dependent full‐order filter is designed such that the developed filter error system is robustly exponentially stable and achieves an exponential H_∞ performance. Sufficient existence conditions for the desired filter are derived and formulated in terms of a set of linear matrix inequalities, and consequently the minimal average dwell time and the corresponding filter are obtained from such conditions for a given system decay degree. A numerical example is presented to demonstrate the potential and effectiveness of the developed theoretical results. Copyright © 2007 John Wiley & Sons, Ltd.     

Simultaneous ℋ︁2/ℋ︁∞ control of uncertain jump systems with functional time‐delays

This paper presents new results pertaining to the control design of a class of linear uncertain systems with Markovian jump parameters. An integral part of the system dynamics is a delayed state in which the time‐delays are mode dependent. The jumping parameters are modelled as a continuous‐time, discrete‐state Markov process and the uncertainties are norm‐bounded. We construct an appropriate Lyapunov–Krasovskii functional and design a simultaneous ℋ︁₂/ℋ︁_∞ controller which minimizes a quadratic ℋ︁₂ performance measure while satisfying a prescribed ℋ︁_∞‐norm bound on the closed‐loop system. It is established that sufficient conditions for the existence of the simultaneous ℋ︁₂/ℋ︁_∞ controller and the associated performance upper bound are cast in the form of linear matrix inequalities. Simulation results are provided and extension to the case where the jumping rates are subject to uncertainties is presented. Copyright © 2007 John Wiley & Sons, Ltd.     

Implementation of the beamline controls at the Florence accelerator laboratory

The new Tandetron accelerator in Florence, with many different beamlines, has required a new organization of all the control signals of the used equipment (slow control).We present our solution, which allows us the control of all the employed instruments simultaneously from a number of different workplaces. All of our equipment has been designed to be Ethernet based and this is the key to accomplish two very important requirements: simultaneous remote control from many computers and electrical isolation to achieve a lower noise level. The control of the instruments requires only one Ethernet network and no particular interfaces or drivers on the computers.     

Polarization effects in non-relativistic ep scattering

The cross section which addresses the spin-flip transitions of a proton (antiproton) interacting with a polarized non-relativistic electron or positron is calculated analytically. In the case of attraction, this cross section is greatly enhanced for sufficiently small relative velocities as compared to the result obtained in the Born approximation. However, it is still very small, so that the beam polarization time turns out to be enormously large for the parameters of e^± beams available now. This practically rules out a use of such beams to polarize stored antiprotons or protons.     

IEEE802.16e的休眠模式性能评估与优化

IEEE802.16e终端具有移动性,导致其系统配置受限于电池容量。而休眠模式作为移动终端的必备功能,它能有效地管理有限的电池容量,延长移动终端的单次充电使用时间。该文回顾了IEEE802.16e移动终端休眠模式的3种功率节省类型,通过建模移动终端的休眠模式,研究了多种功率节省类型相组合的情况,探讨了休眠模式状态下移动终端的平均能量消耗和平均能量节省问题。通过系统模型仿真,提出了基于参数配置变化的休眠模式性能评估及优化的方法。     

曹娥江大闸工程建设关键技术研究与实践

曹娥江大闸枢纽工程地处钱塘江河口,建闸面临闸下淤积、强涌潮、海水侵蚀,软土地基沉降等一系列关键技术问题。本文从如何开展科技创新工作,解决上述问题进行了探索,旨在为强涌潮、多泥沙河口建闸提供借鉴。     

三峡船闸混凝土施工的几项重点技术

针对三峡船闸混凝土结构复杂、施工工序繁多、技术要求高、质量要求严等特点,在施工中对模板、温控、混凝土浇筑等重点技术进行了认真研究,引进、研制和推广应用了许多新材料、新技术、新工艺,为解决三峡船闸混凝土施工的技术难题起到了关键作用,也为今后的类似工程施工提供了宝贵经验．     

GC/MS法测定五加皮保健酒的挥发性特征成分

建立了用气相色谱-质谱联用法测定五加皮保健酒中桂皮醛、4-甲氧基水杨醛、丁香酚、藁本内酯、对甲氧基桂皮酸乙酯含量的方法,并对10个样品酒进行了检测。采用石油醚-乙醚提取法进行样品前处理,HP INNOWAX毛细管柱分离,离子法(SIM)定量。加标回收率均在91．6％以上。检测结果表明,五加皮保健酒中的挥发性特征成分含量在不同产品之间有较大差异。     

铸轧机数字式铸嘴小车的开发与应用

本文介绍了新一代铸嘴小车的结构特点和主要技术参数。其优良的技术性能为工艺的改善提供了保证,从而使造价相对低廉的铸轧机生产出优质的铸轧板。     

用碳酸二甲酯代替光气合成甲苯二异氰酸酯Ⅱ.甲苯二氨基甲酸甲酯的分解

在对于甲苯二氨基甲酸甲酯 (TDC)分解反应系统进行分析的基础上 ,设计并安装了分解反应装置。实验结果表明 :TDC分解的最佳热载体为癸二酸二辛酯 ;最佳混合溶剂为“四氢呋喃 +硝基苯” ;适宜的反应条件是 2 5 0～ 2 70℃ ,2 .6 6 6kPa。热分解的甲苯二异氰酸酯 (TDI)最高产率为 85 5 % ,而催化分解的TDI最高产率为 92 6 %。