时变不确定离散时滞系统的H∞鲁棒控制

研究了一类线性不确定离散时滞系统的H_∞鲁棒控制问题,其时变不确定项是范数有界的,但无需满足匹配条件.基于线性矩阵不等式 (LMI)方法,得到了可H_∞鲁棒镇定的一个充分条件.通过求解一个特定的线性矩阵不等式,即可获得H_∞状态反馈控制器.具体算例说明了该方法的有效性.     

一类多通道不确定时滞大系统分散鲁棒H∞控制：LMI方法

研究多通道不确定时滞大系统的鲁棒分散H_∞控制问题. 假定不确定性是时不变、范数有界, 且存在于系统、时滞和输出矩阵中. 主要针对动态输出反馈控制问题. 基于Lyapunov稳定性理论, 通过设定Lyapunov矩阵为合适的块对角结构, 采用矩阵替换的方法推导出了使多通道不确定时滞大系统可鲁棒镇定, 且满足一定的扰动水平的时滞依赖充分条件即线性矩阵不等式(LMI) 有可行解, 并且给出了具有期望阶数的分散鲁棒控制器的设计方法. 数值例子说明了本文提出方法的有效性.     

不确定多通道奇异时滞系统分散H∞控制

针对不确定多通道奇异时滞大系统, 研究其分散鲁棒H_∞控制问题. 假定不确定性是时不变、范数有界. 基于奇异系统Lyapunov稳定性理论, 通过设定Lyapunov-Krasovskii矩阵为合适的块对角结构, 推导出了使不确定多通道奇异时滞大系统可鲁棒镇定, 且满足一定的扰动水平的充分条件即一组线性矩阵不等式(LMIs)有可行解. 给出了具有期望阶数的分散输出反馈H_∞控制器的设计方法.     

广义时滞系统时滞依赖H∞控制的改进结果

讨论广义时滞系统的时滞依赖控制问题. 基于线性矩阵不等式(LMI)方法和增广Lyapunov泛函, 给出保证系统正则、无脉冲、稳定且满足性能指标的时滞依赖有界实引理. 在此引理的基础上, 给出基于严格LMI的状态反馈控制器存在的时滞依赖条件. 同时给出所需状态反馈控制器的明确表示. 数值例子表明本文的结果改进了已有结论的保守性.     

一类变时滞饱和不确定系统鲁棒H∞滤波器设计

研究一类不确定时变时滞饱和系统的H∞滤波器设计问题.该类系统状态方程中含有时变时滞和有界不确定项,输出方程中含有饱和项,系统的噪声信号功率有界但统计特性未知.本文给出一种线性滤波器结构,提出一种新的设计方法.该方法主要应用Lyapunov-Krasovskii稳定性理论和线性矩阵不等式,来分析和设计滤波器;它能使得时变时滞项,饱和项以及不确定项在设计中得到有效处理,且所设计的滤波器能满足H∞性能指标,滤波器参数通过求解一种线性矩阵不等式来确定.例子的分析与仿真验证了本文方法的有效性.     

参数服从马尔可夫切换中立型时滞系统鲁棒H∞ 控制

研究参数服从马尔可夫切换及具有仿射不确定性的中立型时滞系统H_∞ 状态反馈控制器设计问题. 通过将系统表示为等价的奇异系统, 并利用Moon不等式放大向量积, 基于线性矩阵不等式, 得到了使系统存在无记忆H_∞ 状态反馈控制器与时滞相关的新的充分条件.     

具有状态和测量时滞不确定系统的鲁棒H∞状态估计

考虑一类已知状态和测量时滞且范数有界参数不确定连续时间系统的鲁棒H_∞状态估计问题. 这个问题解的充分条件由二个代数Riccati不等式给出, 它可以保证存在一个渐近稳定状态估计器使得对于所有不确定性从外界干扰到输出估计误差的传递函数满足指定的H_∞指标. 以上这些结果可以推广到一类未知状态和测量时滞且范数有界参数不确定连续系统的鲁棒H_∞状态估计问题, 对于已知状态和测量时滞系统, 所得状态估计器与参数不确定性无关, 而与时滞有关. 对于未知状态和测量时滞系统, 其状态估计器不仅与参数不确定性无关, 而且与时滞也无关.     

时滞LPV系统的H∞控制新方法

研究了具有随参数变化状态时滞的线性参数变化系统的H_∞控制问题,该系统的状态空间矩阵和时滞是实时可测且在闭集内变化的参数的确定函数.提出了一种新的依赖于参数的H_∞性能准则,该准则通过引入附加矩阵解除了系统矩阵与依赖于参数的Lyapunov函数之间的耦合而更易于数值实现.在此基础上设计了系统的H_∞状态反馈控制器,该控制器能够保证相对于所有能量有界的输入信号闭环系统满足给定的性能指标.采用线性矩阵不等式技术,将控制器存在的充分条件转化为凸优化问题.最后用数值仿真验证了所提出算法的可行性.     

线性离散时滞重复过程的H∞控制

首先给出了线性离散时滞重复过程的2D(两维)Roesser模型, 采用线性矩阵不等式方法导出了过程稳定并具有H_∞扰动抑制度的一个充分条件. 通过求一个线性矩阵不等式的可行解来构造系统的一个状态反馈H_∞控制器. 进一步, 通过求解一个线性矩阵不等式凸优化问题得到该过程的最优状态反馈H_∞控制器.     

多时变时滞系统的鲁棒稳定及有界实引理的时滞相关条件

对于多时变时滞系统,引入表示牛顿-莱布尼兹公式中各项的相互关系的自由权矩阵,获得了基于线性矩阵不等式(LMI)描述的系统鲁棒稳定的时滞相关条件,并说明了时滞相关条件和时滞无关条件的相互关系.在此基础上,将其推广到有界实引理的时滞相关条件.所得结果克服了已有结果的保守性.最后给出实例说明本文方法的有效性.     

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.