基于不确定理论的复杂体系优化方法研究

为研究复杂体系的优化方法,首先针对复杂体系的三个发展阶段,提出了三类优化问题;其次通过研究体系结构、体系能力和体系效能之间的内在关系,给出了体系优化的思路,建立了以体系效能为优化目标的复杂体系优化模型;接着利用模糊集理论与证据理论讨论了体系能力评估中定性信息的定量化问题,探索了新的体系能力评估方法,并基于体系效能仿真,采用粗糙集理论建立了求解体系能力权值因子的算法;最后给出了求解优化模型的方法.所提出的优化方法为复杂体系优化问题提出了一种新思路.     

A comparison of four microcomputer operating systems

This article describes a comparative study of four operating systems for IBM-PC compatible microcomputers. The assessment concentrated on the suitability of the operating systems for use in real-time applications, and on their use as development environments for real-time systems. The study evaluated the predictability and the performance of the operating systems in several areas critical in real-time systems by using comparative benchmarks. In addition, a small-scale simulation of a process control system was developed for each of the systems. The operating systems that were studied were UNIX, OS/2, QNX and FlexOS. These operating systems represent a broad spectrum of systems from general purpose operating systems to small, specialized real-time operating systems. The details of the evaluation process are given and a summary of the results is presented.     

Control for smart systems: Challenges and trends in smart cities

There have been tremendous developments in theories and technologies in control for smart systems. In this paper we review applications to various systems that are crucial for the future of smart cities, for example enterprise and manufacturing systems, transportation systems, energy systems, and data centres. Beyond discussing the existing technological trends and the methodological approaches developed so far for managing and controlling such systems, we also provide visions on the future challenges for these systems in these various aspects.     

具有输入饱和的非线性系统的分散输出控制

考虑了一类具有输入饱和的非线性组合大系统的镇定问题。利用李雅普诺夫稳定理论和矩阵理论研究了这类非线性组合大系统的分散输出镇定问题,并给出了一种分散输出镇定控制器的设计。考虑了另一类具有输入饱和的非线性相似组合大系统,由于相似组合系统的结构特点,给出了简洁的分散输出镇定的条件。     

闭环系统故障诊断技术综述

本文着眼于闭环环境下动态系统中的故障诊断问题.介绍了目前闭环系统故障诊断的研究意义, 特别关注了开闭环故障诊断的不同,并概述了现有的闭环系统故障诊断方法. 通过仿真实验比较了典型开环系统和闭环系统中故障诊断的不同性能.最后探讨了闭环系统故障诊断研究中 亟待解决的问题以及未来可能的研究方向.     

Modeling and Identification of Multirate Systems

Multirate systems are abundant in industry; for example, many soft-sensor design problems are related to modeling, parameter identification, or state estimation involving multirate systems. The study of multirate systems goes back to the early 1950s, and has become an active research area in systems and control. This paper briefly surveys the history of development in the area of multirate systems, and introduces some basic concepts and latest results on multirate systems, including a polynomial transformation technique and the lifting technique as tools for handling multirate systems, lifted state space models, parameter identification of dual-rate systems, how to determine fast single-rate models from dual-rate models and directly from dual-rate data, and a hierarchical identification method for general multirate systems. Finally, some further research topics for multirate systems are given.     

Conditions for stabilizability of linear switched systems

This paper investigates some conditions that can provide stabilizability for linear switched systems with polytopic uncertainties via their closed loop linear quadratic state feedback regulator. The closed loop switched systems can stabilize unstable open loop systems or stable open loop systems but in which there is no solution for a common Lyapunov matrix. For continuous time switched linear systems, we show that if there exists solution in an associated Riccati equation for the closed loop systems sharing one common Lyapunov matrix, the switched linear systems are stable. For the discrete time switched systems, we derive a Linear Matrix Inequality (LMI) to calculate a common Lyapunov matrix and solution for the stable closed loop feedback systems. These closed loop linear quadratic state feedback regulators guarantee the global asymptotical stability for any switched linear systems with any switching signal sequence.     

A logic-based information modelling language

A user-friendly language INFOMOD, intended for information modelling and information systems specification, is described. The language, based on predicate logic, fulfills the role of an implementation-independent Conceptual Schema Language. Both static and dynamic aspects of information systems are specifiable in the language. The language has been in practical use for three years, and has been found suitable for many different kinds of systems, such as conventional database systems, computer-aided manufacturing systems, special purpose information systems, and some expert systems.     

On computational stochastic structural dynamics applying finite elements

Summary This article presents a review of the state of the art of techniques on computational stochastic structural dynamics applying the finite elements. Linear systems under random excitations, quasi-linear systems, nonlinear systems excited by stochastic disturbances, and spatially stochastic nonlinear systems are included. For spatially stochastic linear and nonlinear systems under stochastic and deterministic excitations, alternative approaches, proposed by the author, to the so-called stochastic finite element method are introduced. The introduced approaches are free from the limitations of the: (a) normal mode analysis for linear and quasi-linear systems, (b) normal mode with statistical linearization for nonlinear systems, and (c) perturbation approximation techniques for spatially stochastic systems. The introduced approaches for nonlinear systems are applicable to systems undergoing large deformations of finite strains and finite rotations. Selected computed results are included to demonstrate their simplicity and efficiency.     

SOCIAL SYSTEMS THEORY AND PRACTICE: THE NEED FOR A CRITICAL APPROACH

Much of the success of science in explaining, predicting and controlling natural systems can be attributed to the well understood methods that exist for producing and testing theory in the natural sciences. The successful development of social systems science is similarly likely to depend on the elucidation of methods of inquiry suitable to the systems of its concern. Unfortunately the successful methods employed by natural scientists cannot be simply taken over and used in social systems science. Systems scientists who attempt this, risk operating with wholly inappropriate tools when dealing with social systems. Alternative methods of inquiry have been developed in the “soft” systems tradition which are more appropriate for use in relation to one large class of social systems. However, there are many social systems for which even these soft systems approaches are inappropriate. For such social systems there is a need for a more radical and critical approach to producing and verifying social systems science. This paper seeks to demonstrate the need for a critical approach in relation to one class of social systems and shows how only this kind of approach can take account of the special characteristics of this category of social system.     

Crisis IT design implications for high risk systems: systems,control and information propositions

The systems view is presented as a complement to the more traditional scientific approach to help reduce and mitigate risk in high risk systems. Implications for this systemic approach are described, principally in the areas of control and information. Most generally, we investigate how high risk systems use information to maintain control, and how IT systems should be designed to support this activity. Two variations in the systems view – the objective and constructive – are distilled and compared, and for each, the implications for crisis IT systems design are discussed. The limitations of the two variations of the systems view are presented, as is a brief annotated bibliography for further reading about the systems view.     

一种实值属性信息系统的粗集约简方法

本文研究应用粗集理论对实值信息系统属性进行约简的方法，对实值属性信息系统进行约简的根本问题是如何对实值属性离散化，通过对离散化方法与属性约简的关系进行研究，提出实值属性离散化的一种自动确定属性类别的方法，并结合粗集理论给出了对实值属性信息系统约简的算法，用所提出的算法进行了实验，并给出了实验结果。     

A taxonomy and current issues in multidatabase systems

A taxonomy of global information-sharing systems is presented, and the way in which multidatabase systems fit into the spectrum of solutions is discussed. The taxonomy is used as a basis for defining multidatabase systems. Issues associated with multidatabase systems are reviewed. Two major design approaches for multidatabases, global schema systems and multidatabase language systems, are described. Existing multidatabase projects and areas for further research are also discussed     

Synthesis of nonlinear observers: A harmonic-analysis approach

This paper deals with the problem of synthesis of observers for nonlinear systems. Our method is based upon the technique of immersion into bilinear systems and representation theory. We consider bilinear systems and Killing systems, and show how to construct observers for such systems.     

非线性系统控制的逆系统方法(I)——单变量控制理论

介绍非线性系统控制的逆系统方法及相应的单变量非线性系统的控制理论。包括:逆系统方法的基本概念和设计原理,单变量系统α阶积分逆的设计方法,连续单变量系统的控制,逆系统方法在一类分布参数系统和离散时间系统上的推广示例。     

含未知输入的广义系统的状态与输入估计

研究了含未知输入的广义系统的输入解耦观测器设计问题. 在系统脉冲能控的条件下通过系统输入-状态对的非奇异变换, 把此问题等价地转化为正常状态空间系统的相应问题. 用大家熟知的方法设计正常状态空间系统的观测器, 从而得到广义系统的输入解耦观测器. 然后用广义系统的观测器状态和系统输出的线性组合渐近估计系统的状态与未知输入.     

不确定非线性环链系统的分散鲁棒控制

提出了环链系统和一类不确定非线性环链系统,利用线性代数理论,给出了实现环链系统的充要条件,运用李雅普诺夫稳定理论和矩阵理论研究了不确定非线性环链系统的鲁棒镇定,并给出了一种非线性鲁棒镇定控制器的设计,还考虑了一类非线性环链相似组合大系统,给出了分散鲁棒镇定条件,最后给出数值例子说明设计方法的有效性。     

仿射非线性奇异系统的受控分布

研究非线性奇异系统的受控不变分布问题.讨论了非线性奇异系统的受控不变分布算法与该系统经过状态反馈转化为正常非线性系统的受控不变分布算法的关系.得到了在一定条件下,正则非线性奇异系统的受控不变分布算法与该系统经过状态反馈转化为正常非线性系统的受控不变分布算法的一致性.并给出一个例子说明本文的结果.     

DeepComp: towards a balanced system design for high performance computer systems

Today, cluster-based computing is the mainstream architecture for high end computer systems. Balanced system design is critical for large scale cluster systems to achieve high efficiency. This paper addresses the practice on DeepComp high end computer systems toward a balanced system design. Methodologies of designing balanced large scale cluster systems are given. A method for balancing central processing unit (CPU) and memory hierarchy is addressed. For balancing computing nodes and I/O systems, two approaches are given: maximum bandwidth criterion and maximum number of computing nodes which can concurrently access I/O systems. Experiences of Lenovo high end cluster systems show that above methods are effective. Lenovo strategies toward a balanced system design for both peta and 10 peta scale high productivity computing systems (HPCSs).