Robust reliable H∞ control for discrete-time Markov jump linear systems with actuator failures

The robust reliable H∞ control problem for discrete-time Markovian jump systems with actuator failures is studied.A more practical model of actuator failures than outage is considered.Based on the state feedback method,the resulting closed-loop systems are reliable in that they remain robust stochastically stable and satisfy a certain level of Hex disturbance attenuation not only when all actuators are operational,but also in case of some actuator failures.The solvability condition of controllers can be equivalent to a feasibility problem of coupled linear matrix inequalities (LMIs).A numerical example is also given to illustrate the design procedures and their effectiveness.     

企业战略研究方法论的综合集成与创新——概念框架与初步的理论假设

基于系统概念与系统方法论的新进展 :系统隐喻、系统方法论的系统体系及“全面系统干预”,提出了对企业战略各学派的研究方法论 (简称企业战略研究方法论 )综合集成与创新的总思路、概念框架及初步的理论假设 ,以克服企业战略研究方法论在实践中遇到的困难.     

Soft Systems Methodology and Systems Maintenance

Business systems maintenance represents a large proportion of the work of IT staff in most organizations. Many methodologies relevant to IT concentrate on systems development and give little attention to systems maintenance. In this paper we discuss the relevance and benefits of the Soft Systems Methodology (SSM) to systems maintenance. Payroll administration is then used to provide an outline illustration of the use of SSM for systems maintenance projects. Aspects of the use of SSM for systems maintenance projects are also discussed.     

不确定离散时滞系统的鲁棒容错控制

考虑了线性离散时滞系统的容错控制问题,给出了传感器失效时系统具有完整性的一个充分条件,并推广到执行器失效的情况。在此基础上得到了更接近实际系统的不确定时滞离散系统问题,给出鲁棒容错控制时滞系统的设计方法和步骤,并用实例验证了所给方法的有效性。     

Methodological foundations of systems methodologies

In social systems science generally, and in management science particularly, recent developments in the variety of types of specific problem-solving methodologies (under the rubric of hard and soft systems approaches) have given an impetus to a line of inquiry, as well as debate on the nature of those methodologies. On the one hand, there has been the view that what we are witnessing is a form of Kuhnian crisis. On the other hand, a complementarist view of developments has been argued and a contingency approach proposed. But one thing has been common among the competing views: a belief that the prospects for further advances in the design and application of those methodologies, and in resolving the current controversies, lie in serious attempts to reconsider and clarify the underlying metatheoretical assumptions and concerns. This paper is an attempt to contribute to such an endeavor. A brief exposition of three methodological foundations (namely, empiricism, hermeneutics, and critique) is made, not only with the purpose of highlighting the nature as well as the limits of their epistemological and ethical claims, but also as a basis for illuminating both the nature of contemporary work on systems inquiry, design, and problem solving and the ongoing debate on what constitutes appropriate criteria for choice of specific methodologies.     

Robust reliable H∞ control for discrete-time Markov jump linear systems with actuator failures

The robust reliable H∞ control problem for discrete-time Markovian jump systems with actuator failures is studied. A more practical model of actuator failures than outage is considered. Based on the state feedback method, the resulting closed-loop systems are reliable in that they remain robust stochastically stable and satisfy a certain level of H∞ disturbance attenuation not only when all actuators are operational, but also in case of some actuator failures, The solvability condition of controllers can be equivalent to a feasibility problem of coupled linear matrix inequalities （LMIs）. A numerical example is also given to illustrate the design procedures and their effectiveness.     

企业战略研究的系统方法论

首先通过分析系统的最重要但常常被忽视的特征来深入理解系统概念,给出在实践中把握系统概念的具有可操作性的途径; 通过知识论域体系、系统方法论的系统以及全面系统干预元方法论,进一步理解系统方法论的概念以及在实践中应用系统方法论的途径. 然后基于对系统和系统方法论概念的上述理解和企业战略研究的诸多学派,提出了一个企业战略研究的系统方法论,并详细介绍了 一个案例,在案例中还对定位学派的具体的研究方法论做了拓展.最后指出企业战略研究的系统方法论是选择众多企业战略研究方法 论的元方法论,可用于各种问题情境下的企业战略研究,而且其应用系统思考的途径还可以推广应用于企业管理的其它领域.     

Total systems intervention and human inquiry: The search for a common ground

Total Systems Intervention (TSI) is an approach to intervening in problem situations which has much to offer where complex interacting issues need to be addressed by the complementary use of intervention methodologies. That such an approach has much in common with Action Research (AR) has been recognized, with much recent effort being devoted to the relationship between AR and Critical Systems Thinking (CST), the theoretical endeavor underpinning TSI. This paper further develops this line of debate and relates AR or Human Inquiry (HI) more directly to TSI, using an information systems intervention to enhance the study. The outcome is a demonstration of how TSI implicitly uses techniques informed from the field of Action Research, and how a more thorough synthesis of HI with TSI might serve to improve the overall intervention process.     

Problem contexts—A consultant's perspective

This paper is an attempt at building on the idea of a “system of systems methodologies” to introduce a dynamic element in its use and thereby increase its effectiveness. The author, a practicing management consultant, has perceived the advantages of classifying various systems methodologies on the basis of problem contexts. Additional benefit, assesses the author, will be obtained by recognizing the dynamic nature of these contexts. Some insights have been developed on this theme. Areas needing further theoretical enhancement and action research are also identified.     

System dynamics as a systems-based problem-solving methodology

Systems dynamics is concerned with using systems ideas to increase understanding of various types of phenomena and to aid in the decision-making which determines action upon the processes involved. Developments within system dynamics have occurred mainly independently of advances in the broader systems movement. In this paper an attempt is made to bring to bear on system dynamics some recent work which considers the character of systems-based problem-solving methodologies. System dynamics is placed within a framework which enables the relative strengths and weaknesses of different approaches to be identified. This leads to a deeper understanding of some of the critiques of system dynamics and enables some issues to be outlined which may help to strengthen the theoretical base of system dynamics methodology and hence improve its ability to tackle practical situations.     

Research on fault-tolerant control of networked control systems based on information scheduling

A kind of networked control system is studied; the networked control system with noise disturbance is modeled based on information scheduling and control co-design. Augmented state matrix analysis method is introduced, and robust fault-tolerant control problem of networked control systems with noise disturbance under actuator failures is studied. The parametric expression of the controller under actuator failures is given. Furthermore, the result is analyzed by simulation tests, which not only satisfies the networked control systems stability, but also decreases the data information number in network channel and makes full use of the network resources.     

基于马尔可夫过程的k/n(G)系统共因失效分析

利用马尔可夫过程研究了发生共因失效的k/n(G)系统可靠度计算方法。建立了共因失效时部件全部失效和共因失效时多个部件失效这两种情况下,不可修系统和可修系统的马尔可夫模型。分析了系统部分部件属于共因失效组的可靠度计算方法。利用算例验证了所建立的模型的有效性,结果显示,所建立的马尔可夫模型适用范围广,计算方便。     

Enhancing Emancipatory Systems Methodologies for Sustainable Development

Our interest lies in applying the principles of critical systems thinking to human activity systems in developing countries in situations where issues of natural resource sustainability constrain the feasible set of long-term strategies. The concept of sustainable development provides an expanded domain for critical systems thinking. The fundamental values underpinning sustainable development are that both intragenerational and intergenerational equity are important. As a consequence, key stakeholders are often excluded from power-sharing within current social systems. Addressing these issues requires renewed focus on emancipatory commitment and methodologies. To date, Ulrich's critical systems heuristics is the only critical systems methodology that offers practicable tools for emancipation. A case study analysis in Tigray, northern Ethiopia, provides insights in relation to the application of critical system heuristics to issues of sustainable development and highlights the need to extend the use of critical systems heuristics beyond the design and monitoring of structured interventions.     

A critique of hierarchy theory

In our zeal to apply models successfully, failures of the model are often overlooked. A model may be used for quite some time before its success is questioned or before the model fails to be applied successfully. Since hierarchy theory has been deemed successful in the systems field, it is necessary and appropriate to critique the development and application of hierarchy theory using the framework presented inCreative Problem Solving (Flood and Jackson, 1992). That framework proposes a critique that uses the four areas of theory, utility, ideology, and methodology in reviewing a systems theory. It is important to examine hierarchy theory through the analytical filter of critical systems thinking if we are genuinely to understand what hierarchy theory has to offer systems thinking in the exploration of complex situations.     

不确定时滞系统多目标约束下的满意容错控制

针对一类具有不确定参数、干扰输入和时滞特性的非线性系统,研究了当执行器发生故障时的满意容错控制问题。在更实际、更一般的执行器连续增益故障模型下,采用一种含有时滞记忆的状态反馈控制律,分析了鲁棒稳定性能与H∞指标的相容性,并在相容指标约束下,给出了鲁棒H∞满意容错控制器存在的充分条件和设计方法。仿真算例验证了该方法的有效性。     

A Model for Design of Human Activity Systems

A background is given to the common failures of management information systems and the authors' view of the causes behind these failures. There seems to be a lack of effective methods for analyzing information requirements. Different scientific methods are discussed as to their propensity for analyzing the information requirements. The importance of the systems design approach instead of the system improvement approach is emphasized. The concept of Human Activity Systems is discussed and an analysis of the interdependence of the soft and hard parts of these systems indicates that an integrated view is necessary. A methodology based on a systemic and systematic analysis of the information requirements in an organization is proposed. This methodology focuses the settings of the decisions on all levels in organizations and also indicates organizational discrepancies and information imbalances. The methodology can be regarded as a dynamic, learning system.     

仿真系统VV&A发展的五大关键问题

仿真系统已经成为军事和民用领域生产和研究不可缺少的工具,仿真可信度问题是影响仿真系统向更宽广领域应用发展的重要问题。仿真系统VV&A重要性日益被仿真用户、开发者和管理者所认识。本文探讨仿真系统VV&A发展需要解决的五大关键问题,最后对我国仿真系统VV&A的发展提出几点建议。     

Systemic praxis in the education of the agricultural systems practitioner

This paper describes the context and the systemic experiential theories that have informed the praxis of educating agricultural systems practitioners. The praxis has involved a process of action research with students and with clients in farming and other rural community organizations. The praxis encourages learners to bring a range of methodologies of inquiry to bear upon problematic issues, contingent upon the nature of such issues. Informed by a number of different theories, and by reflecting on our own work, an earlier model of a nested hierarchy of systems of inquiry has been reconstructed to become a more useful guide to educational strategies: Each contingent methodology can now be seen to have its own learning, meta-learning, and epistemic learning dimensions. A key to enriched learning for responsible changes in agriculture and rural development lies in the facilitation of the consciousness of, and competency at, such a systemic pluralism of methodologies.     

Use of Archetypal Structures in Urban Dynamics

The paper demonstrates the use of systems archetypes as a practical method to understand the impact of urban policies and programs on urban dynamics. Systems archetypes are generic templates to represent the structural and behavioral insights in dynamic systems. They highlight counterintuitive behavior of social systems and the recursive nature of complex systems. This paper maps systems archetypes pertaining to the failures in urban programs, as described by Prof. J.W. Forrester in his classic book Urban Dynamics. ‘Fixes that backfire’ is a systems archetype that construes a situation where a fix effective in a short term creates long term behavioral side effects which might need even more fixes. This archetype is mapped onto the failures in urban programs. The insights to the reasons of failures of urban programs through the systems archetypes lens will enable us bring a change in the society and assist policy makers by being cautious of the unintended consequences while devising urban policies. Therefore, an approach has been proposed to deal with urban change by applying archetypal structures to urban problems. The approach illustrated in this paper will enable urban governors and planners, distinguish programs and policies that may or may not lead to desired dynamics.