广义系统鲁棒镇定的H_∞方法

利用Ｈ∞控制方法讨论含不确定参数的广义系统鲁棒镇定问题。首先将广义系统的稳定性条件表示为Ｈ∞范数的形式,然后利用Ｈ∞范数与Ｒｉｃｃａｔｉ代数矩阵不等式的关系给出了含不确定参数的广义系统可镇定的条件,从而将鲁棒控制设计问题转化为求解Ｒｉｃｃａｔｉ不等式的问题     

广义系统鲁棒镇定的H∞方法

利用Ｈ∞控制方法讨论含不确定参数的广义系统鲁棒镇定问题。首先将广义系统的稳定性条件表示为Ｈ∞范数的形式,然后利用Ｈ∞范数与Ｒｉｃｃａｔｉ代数矩阵不等式的关系给出了含不确定参数的广义系统可镇定的条件,从而将鲁棒控制设计问题转化为求解Ｒｉｃｃａｔｉ不等式的问题。     

状态和控制输入不确定时滞系统基于观测器的鲁棒H_∞控制

研究一类同时存在状态和控制输入不确定性的时滞系统基于观测器的鲁棒Ｈ∞控制问题。系统的不确定性参数是时变的,但其结构已知。通过构造观测器并利用观测器状态进行反馈控制,使系统不仅鲁棒镇定,而且具有一定的Ｈ∞性能。鲁棒Ｈ∞控制器的设计可通过求解两个代数Ｒｉｃｃａｔｉ方程得到     

状态和控制输入不确定时滞系统基于观测器的鲁棒H∞控制

研究一类同时存在状态和控制输入不确定性的时滞系统基于观测器的鲁棒Ｈ∞控制问题。系统的不确定性参数是时变的,但其结构已知。通过构造观测器并利用观测器状态进行反馈控制,使系统不仅鲁棒镇定,而且具有一定的Ｈ∞性能,鲁棒Ｈ∞控制器的设计可通过求解两个代数Ｒｉｃｃａｔｉ方程得到。     

非线性时滞摄动系统的H∞鲁棒控制

研究具有时滞的非线性不确定性系统的Ｈ∞鲁棒控制问题。基于代数Ｒｉｃｃａｔｉ方程的正定解设计出状态反馈控制器使得闭环系统满足相应的Ｈ∞鲁棒性能准则。     

不确定线性系统的输出反馈鲁棒H∞控制

研究了具有范数有界参数不确定线性系统的输出反馈鲁棒Ｈ∞控制问题，给出了该系统带Ｈ∞指标γ鲁棒稳定的充要条件，以及该系统静态输出反馈带Ｈ∞指标γ鲁棒镇定的充要条件，并且指出，系统的动态输出反馈鲁棒Ｈ∞镇定问题可等价为广义系统的静态输出反馈鲁棒Ｈ∞镇定问题，所给出的方法，其设计过程只需解一个特殊的Ｒｉｃｃａｔｉ方程最后通过实例论证了方法的有效性。     

状态时滞时变不确定系统的鲁棒H∞ 输出反馈控制器设计

主要研究了存在状态滞后的线性时变不确定时滞系统的鲁棒∞控制分析和综合问题,给出了对所有容许不确定性,被控对象可二次镇定和满足从干扰输入到控制输出的Ｈ∞范数界约束的动态输入出反馈鲁棒Ｈ∞控制分析结果,将不确定时滞系统的鲁棒Ｈ∞输出反馈控制器设问题等价对两个线性时不变系统的状态反馈标准Ｈ∞控制问题,并由此得到反馈阵和观测阵,了终得到鲁棒Ｈ∞控制器综合设计方法。     

一类不确定非线性系统的鲁棒H∞控制

讨论了在自由系统和输入通道都带有有界不确定性的仿射非线性系统的鲁棒H∞ 控制问题,给出了状态反馈控制设计,对所有允许的不确定性它既能保证关于H∞模的干扰 抑制品质,又能镇定该系统.同时指出如果一个相应的Hamilton-Jacobi不等式有非负解,则 该不确定仿射非线性系统的鲁棒H∞控制问题可解.     

一类具有范数有界的非线性不确定性时滞系统的鲁棒H∞控制器设计

研究一类具有有界范数非线性不确定性的线性时滞系统的鲁棒Ｈ∞控制，提出一种鲁棒Ｈ∞控制器的设计方法。该控制器不仅能鲁棒镇定原不确定系统，还能保证闭环系统一定的Ｈ∞性能。     

含有不确定性的非线性互联系统的鲁棒分散H∞控制

讨论了含有不确定性非线性互联系统的鲁棒分散Ｈ∞控制问题,建立了鲁棒Ｈ∞控制之间的联系,在这种联系基础上,基于Ｈａｍｉｌｔｏｎ－Ｊａｃｏｂｉ不等式给出了含有不确定性互联系统的鲁棒分散Ｈ∞控制问题存在的充分条件,分别构造出状态反 输出反发散控制器以确保闭环系统从外部干扰输入到控制输出的Ｌ２增益小于或等于一预先给定的正数。     

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.     

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.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate