Systems thinking for information systems development

Although many information systems development methods (ISDMs) are available, past experience indicates that none of them completely supports the design process. One of the major problems is that the traditional ISDMs represents a poor match for some subsystems or dimensions involved in the information systems design (ISD). This paper presents an integration and interpretation of recent research on the mismatch of the ISDMs with the ISD process and suggests that systems ideas can be used to learn about and clarify our perceptions of the ISD processes. First, some important systems concepts such as systems, subsystem, dimensionality, system types, and characteristics are introduced. Second, some lessons of mismatch learned in the past that are related to those systems concepts are discussed. The discussion includes experiences learned through the ISD process such as communication problems, inadequate analysis of systems maintenance, lack of understanding of the relationship between the nature of the subsystem/dimension to be represented and the selection of tools, difficulties in integrating subsystems and dimensions, as well as Brooks' Law along with others. Third, some recommendations are given concerning how to avoid mismatch with a systems concept phase. Fourth, some guidelines are provided for implementing the tasks of the systems concept phase. Finally, a number of areas where research appears needed are mentioned.     

Decentralized adaptive fuzzy control of time-delayed interconnected systems with unknown backlash-like hysteresis

The problem of decentralized adaptive fuzzy control for a class of time-delayed interconnected nonlinear systems with unknown backlash-like hystersis is discussed. On the basis of the principle of variable structure control （VSC） and by using the fuzzy systems with linear adjustable parameters that are used to approximate plant unknown functions, a novel decentralized adaptive fuzzy control strategy with a supervisory controller is developed. A general method, which is modeled the backlash-like hysteresis, is proposed and removes the assumption that the boundedness of disturbance, and the slope of the backlash-like hystersis are known constants. Furthermore, the interconnection term is supposed to be pth-order polynomial in time-delayed states. In addition, the plant dynamic uncertainty and modeling errors are adaptively compensated by adjusting the parameters and gains on-line for each subsystems. By theoretical analysis, it is shown that the closed-loop fuzzy control systems are globally stable, with tracking error converging to zero. Simulation results demonstrate the effectiveness of the approach.     

Characteristic polynomial assignment in F-M model Ⅱ of 2-D systems

The problems of characteristic polynomial assignment in Fornasini-Marchesini (F-M) model Ⅱ of 2-D systems are investigated. The corresponding closed-loop systems described by F-M model Ⅱ are obtained via the state feedback.Using the algebraic geometry method, the characteristic polynomial assignment in the closed-loop systems is discussed. In terms of the theory of algebraic geometry, the problem of characteristic polynomial assignment is transferred to the one whether a rational mapping is onto. Sufficient conditions for almost arbitrary assignment coefficients of characteristic polynomial in F-M model Ⅱ of 2-D systems via state feedback are derived, and they are available for multi-input cases. It also has been shown that this method can be applied to assign the characteristic polynomial with output feedback. The sufficient conditions for almost arbitrary assignment coefficients of characteristic polynomial of multi-input 2-D systems described by F-M model Ⅱ with output feedback are established.     

大型管理信息系统分解的模糊关联方法及其应用

针对大型管理信息系统功能结构分解问题，提出一种利用信息处理过程之间的模糊关联性来识别各个子系统，从而达到系统分解目的的方法，并将方法应用于某生产企业管理信息系统和广东省一个市级政府经济管理信息系统总体设计中.     

Decentralized robust stabilization of discrete-time fuzzy large-scale systems with parametric uncertainties: a LMI method

1. INTRODUCTION Large-scale dynamic system theory has been intensi- vely studied during the past decade[1～3], but for fuzzy large-scale systems, namely large-scale systems comp- osed of a series of fuzzy subsystems, has been seldom done in literature. In Ref.[4], decentralized stabiliz- ation problem of fuzzy large-scale systems composed of a series of fuzzy subsystems was considered. Sufficient conditions for asymptotic stability of the fuzzy large-scale system and design methods of dec…     

Stability analysis of decentralized adaptive backstepping control systems with actuator failures

In this paper, the authors analyze the stability of a class of interconnected systems with subsystem unmodeled dynamics and dynamic interactions employing decentralized adaptive controllers designed by Wen, Zhou, and Wang (2008) in the presence of actuator failures. It will be shown that the global stability of the remaining closed-loop system is still ensured and the outputs are also regulated to zero when some subsystems break down.     

带状随机线性系统状态的估计问题

针对目前关于广义系统状态估计的研究现状 ,即几乎所有的讨论都集中在奇异矩阵为方阵的情况 ,讨论了广义逆矩阵和矩阵的奇异值分解问题。首次提出了带状随机系统的状态估计问题 ,利用矩阵的奇异分解理论给出了带状广义连续线性系统的奇异值标准形式。基于标准形式 ,利用广义逆矩阵的性质 ,在两种情况下将系统分解成两个子系统 ,通过估计子系统的状态 ,得到了该系统状态的最优预测和滤波递推方程。     

不确定切换组合大系统的鲁棒分散控制

考虑了一类不确定切换组合大系统的鲁棒分散状态反馈镇定问题。利用单李雅普诺夫函数方法,得到了不确定切换组合大系统鲁棒可稳的充分条件。在互相关联的低维子系统的状态矩阵和控制输入矩阵同时带有未知、时变但有界的不确定性、各自的单个子系统均不能被镇定的情况下,基于凸组合技术和线性矩阵不等式方法,设计出分散状态反馈控制器及相应的分散切换策略,使得闭环系统渐近稳定。仿真结果表明所设计方法的正确有效性。     

The Similar Structures and Control Problems of Complex Systems

1 Introduction1 We consider the naturally evolving complex systems, such as biotic and social systems. In their evolving process, they always make up their weaknesses and develop their favorable factors. In such a way, their structures are gradually formed. In the structures of these systems, a feature is noteworthy, i.e., the local(partial) structure is similar to the global(overall). For social systems, for instance, in a country, the management organization of a province is similar to tha…     

基于LMI的连续时间模糊大系统的分散镇定

讨论了连续时间模糊大系统的分散镇定问题。整个模糊大系统由m个相互关联的T-S子模糊系统组成。基于李亚普诺夫稳定性理论及大系统分散控制理论,将单个模糊系统的稳定性条件推广到关联模糊大系统的情形,给出了保证该模糊大系统闭环渐近稳定的分散化并行分布补偿(decentralizedparalleldistributedcompensation,DPDC)控制器的设计方法。这些分散控制器的存在条件均以LMI的形式出现,因此可通过Matlab的LMI工具箱有效地对其进行求解。仿真例子说明了所提方法的有效性。     

基于模糊逻辑系统的复杂相似系统分散全息控制设计

针对复杂系统提出信息库的概念，以此为基础描述了复杂相似系统的概念。针对一类具有相似结构的、由二维子系统组成的复杂系统，采用经典Lyapunov方法和模糊逻辑系统，充分利用相似结构信息和匹配系数，分别给出了设计被控复杂系统镇定和跟踪分散全息控制器的方法。实例仿真结果表明本文所提出的方法是有效的。     

Disturbance Attenuation State-Feedback Control for Uncertain Interconnected Systems

This paper studies the problem of robust H∞ control design for a class of uncertain interconnected systems via state feedback. This class of systems are described by a state space model, which contains unknown nonlinear interaction and time-varying norm-bounded parametric uncertainties in state equation. Using the Riccati-equation-based approach we design state feedback control laws, which guarantee the decentralized stability with disturbance attenuation for the interconnected uncertain systems. A simple example of an interconnected uncertain linear system is presented to illustrate the results.     

Parallel simultaneous stabilization of a set of Port-Controlled Hamiltonian systems subject to actuator saturation

This paper investigates parallel simultaneous stabilization (PSS) of a set of multi-input nonlinear Port-Controlled Hamiltonian (PCH) systems subject to actuator saturation (AS), and proposes a number of results on the design of PSS controllers for the PCH systems with AS. Firstly, the case of two PCH systems with AS is studied. Exploring the special property of the saturation nonlinearity and the structural properties of dissipative Hamiltonian system, the two systems are combined to generate an augmented PCH system, with which some results on the control design are then obtained. When there are external disturbances in the two systems, a robust PSS controller is designed for the systems. Secondly, the case of more than two PCH systems with AS is investigated, and several new results are proposed for the PSS problem. Finally, two illustrative examples are presented to show that the stabilization controllers obtained in this paper work very well.     

Non-fragile guaranteed cost control for uncertain neutral large-scale interconnected systems

This paper focuses on the problem of non-fragile decentralized guaranteed cost control for uncertain neutral large-scale interconnected systems with time-varying delays in state, control input and interconnections. A novel scheme, viewing the interconnections with time-varying delays as effective information but not disturbances, is developed. Based on Lyapunov stability theory, using various techniques of decomposing and magnifying matrices, a design method of the non-fragile decentralized guaranteed cost controller for unperturbed neutral large-scale interconnected systems is proposed and the guaranteed cost is presented. The further results are derived for the uncertain case from the criterion of unperturbed neutral large-scale interconnected systems. Finally, an illustrative example shows that the results are significantly better than the existing results in the literatures.     

大规模系统中冲突的协商解

本文分析了由多个子系统构成的大系统中的决策问题, 研究了各子系统之间目标出现冲突时的解及调解方法。文章采用文献[6]中的多人多目标冲突模型来描述大系统中的冲突决策问题, 提出了大系统中冲突的协商解的概念, 并研究了其协商解的求取方法。     

广义连续随机线性系统的最优递推问题

讨论了广义连续随机线性系统的最优递推问题,利用矩阵的奇异值分解理论,给出了广义连续随机线性系统的奇异值标准形式,基于标准形式,在两种情况下,将系统分解成两个子系统,通过对子系统状态估计的研究,得到了该系统的最优递推方程。结果表明,对于广义系统,该方法有效地减少了计算量。     

Characteristic Polynomial Assignment in 2-D System

CONTROL THEORY AND APPLICATION1. IWTSODUCTIONTwo-dimensional (2-D) systems have mad applications such as 2-D digital Kalman filtering, image processing,etc., and have been studied extensively during the past two decades [1, 2]. The characteristic polynomialassignment problem for 2-D systems is one of the most important problems in the research of 2-D systems,and has been considered by many authors. In reference 13], the author has presellt a method for coefficielltassignmellt …     

基于价值导向策略的时延预测补偿算法

针对工业控制模型的复杂化以及由此引起的时延叠加问题,利用预测思想,以解耦子系统为模型,采用动态矩阵控制(DMC)算法作了分析,同时充分考虑了子系统间的关联,采用价值导向策略优化调度算法,使控制作用快速平稳过渡,并在此基础上提出了针对复杂系统的时延预测补偿算法(TDCDMC)。由于时延导致了控制作用无法及时跟踪系统变化,引入了补偿因子和过渡因子在线整定预测控制量和时延控制量,对于突变频繁的时延系统亦能迅速跟踪输入。仿真结果表明,这种改进算法的时延补偿性能良好,保证了控制的稳定性和快速性。     

带有参数的数据包络分析C2GS2模型--PC2GS2

数据包络分析是系统工程的一种重要方法 ,特别适宜处理多输入、多输出的复杂系统的评价问题。在数据包络分析C2 GS2 模型的基础上 ,通过对评估决策单元的输入进行调整 ,得出了一个带有参数的C2 GS2 ———PC2 GS2 模型。探讨了模型的有关性质 ,给出了阈值的概念 ,并通过理论分析和实例验证 ,说明阈值能更好地描述决策单元的相对信息     

多输入非线性串级系统的自适应控制

对一大类含有未知参数的多输入非线性串级系统 ,基于 backstepping递推设计方法 ,进行了自适应控制设计。当自适应控制律作用于该系统时 ,闭环系统的所有信号是有界的 ,并且原系统的状态收敛于零.