不确定系统鲁棒容错H_∞控制的LMI设计方法

针对不确定线性系统.研究了执行器失效情况下鲁棒容错H∞控制问题.基于连续增益故障模式.利用线性矩阵不等式LMI推导了系统H∞指标约束下鲁棒容错镇定的充要条件.分别给出了输出反馈和状态反馈H∞控制器的设计方法.通过引入变量代换.将求解输出反馈H∞指标约束的鲁棒容错控制器的可解条件转化为标准的LMI.所获得的控制器不仅能使故障系统鲁棒稳定,并且能达到给定的H∞性能指标.仿真实例验证了所提出设计方法的有效性.     

容错控制系统鲁棒H∞和自适应补偿设计

通过设计动态输出反馈控制策略研究线性时不变系统执行器故障下的鲁棒自适应容错H∞控制问题. 结合自适应技术和线性矩阵不等式(Linear matrix inequalities, LMI)技术, 设计一个控制策略同时实现系统的故障补偿控制和性能优化控制. 在设计中, 提出由自适应律在线调节控制增益方程补偿未知执行器故障和摄动; 并设计一个基于模式依赖李亚普诺夫方程的LMI条件解出控制参数及次优H∞性能. 所设计的动态输出反馈控制器可以处理一般执行器卡死故障, 并得到更少保守性的H∞性能指标. 此外, 一个更具挑战性的问题, 即通过自适应机构补偿故障致使系统多少性能退化得到论证. 所提方法的有效性由一个解耦线性化动态飞行器系统仿真验证.     

一类不确定系统鲁棒容错D-稳定性分析

研究不确定系统D-稳定鲁棒容错H_∞控制问题.基于连续型执行器故障模式,利用线性矩阵不等式(LMI),给出了系统D-稳定的鲁棒容错输出反馈控制器存在的充分条件,并将动态输出反馈控制器设计方法归结为求解一族线性矩阵不等式组.仿真示例表明,无论执行器是否发生故障,所得到的动态输出反馈控制器不仅保证闭环系统是D-稳定的,而且满足给定的H_∞干扰指标,从而验证了所提出的控制器设计方法的有效性.     

基于输出反馈的鲁棒容错D-稳定性分析

研究线性不确定系统基于输出反馈的鲁棒容错控制问题.基于连续型执行器故障模式,利用线性矩阵不等式LMI,给出了系统基于输出反馈的鲁棒容错D-稳定的充分条件,并把控制器的设计方法归结为求解一族线性矩阵不等式组.与常规的方法相比,给出的控制器不仅保证闭环系统对执行器故障具有完整性,并且使闭环系统的极点配置在指定区域D中.通过仿真示例表明,无论执行器发生故障与否,得到的基于输出反馈的鲁棒容错控制器均保证闭环系统是D-稳定的,从而验证了所提出设计方法的有效性.     

不确定广义模糊系统的鲁棒模糊H∞控制器设计

研究了不确定广义模糊系统鲁棒H∞状态反馈控制器和动态输出反馈控制器设计问题。在E确定其它系数矩阵均存在不确定性情况下，给出鲁棒模糊H∞状态反馈控制器和动态输出反馈控制器存在的充分条件。鲁棒H∞状态反馈控制律的设计可能通过求解线性矩阵不等式得到，而动态输出反馈鲁棒H∞控制器可通过定义新变量得到，所求控制器使闭环系统对所有的不确定性稳定且满足H∞性能指标γ。     

一类不确定系统鲁棒容错D-稳定性分析

研究不确定系统D-稳定鲁棒容错H_∞控制问题.基于连续型执行器故障模式,利用线性矩阵不等式(LMI),给出了系统D-稳定的鲁棒容错输出反馈控制器存在的充分条件,并将动态输出反馈控制器设计方法归结为求解一族线性矩阵不等式组.仿真示例表明,无论执行器是否发生故障,所得到的动态输出反馈控制器不仅保证闭环系统是D-稳定的,而且满足给定的H_∞干扰指标,从而验证了所提出的控制器设计方法的有效性.

     

不确定时滞系统的保代价H∞鲁棒可靠控制

针对一类不确定时滞受扰系统,研究了在执行器发生故障情况下系统具有保代价的H_∞鲁棒可靠控制器设计问题。根据Lyapunov稳定性理论,得到了系统存在保代价H_∞鲁棒可靠控制器应满足的一个矩阵不等式,进一步将这个矩阵不等式转化为线性矩阵不等式（LMI）,并给出了系统状态反馈控制器的设计方法。利用论文方法设计的鲁棒可靠控制器能够使得时滞系统对于任意允许的不确定量以及一个预先指定执行器子集中任意执行器失效不仅具有鲁棒容错性,并且使系统存在保成本上界以及具有指定H∞范数的干扰抑制能力。仿真结果表明了该可靠控制器设计方法的有效性。     

具有时变不确定性的线性时滞系统的鲁棒H_∞控制

研究具有一般形式的不确定线性时滞系统的鲁棒 H∞ 状态反馈控制器设计问题 .基于二次 H∞ 性能概念 ,首先证明了若存在鲁棒 H∞ 动态状态反馈控制器 ,则必存在鲁棒 H∞ 静态状态反馈控制器 ,然后利用线性矩阵不等式给出了鲁棒 H∞ 静态状态反馈控制器存在的充分条件和构造方法 ,最后给出一个算例验证本文方法的有效性     

一类不确定Lurie时滞奇异系统的鲁棒H∞控制

研究一类具有不确定性的Lurie时滞奇异系统的鲁棒稳定性分析和H∞状态反馈控 制器设计方法.针对一类具有参数不确定性、未知时滞的奇异系统,得出了系统鲁棒稳定和 鲁棒H∞状态反馈控制器存在的充分条件,它能使得不确定Lurie时滞奇异系统的解在所容 许的范围内是正则的、无摄动的和稳定的;而且还得出了基于线性矩阵不等式(LMI)的鲁棒 H∞状态反馈控制器的设计方法,使得闭环系统具有鲁棒稳定性和H∞性能.     

数值界不确定关联大系统分散鲁棒H∞控制

针对一类状态矩阵、控制矩阵及关联矩阵存在数值界不确定性的关联大系统,研究其分散鲁棒H∞状态反馈控制器设计问题.基于有界实引理将存在鲁棒分散H∞状态反馈控制器的条件归结为一个非线性矩阵不等式求解问题,采用同伦迭代线性矩阵不等式方法求解分散控制器,使闭环大系统鲁棒稳定,并且满足给定的H∞性能指标.最后通过一个数值例子来说明该设计方法的有效性.     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.