Sensor fault-tolerant observer applied in satellite attitude control

The observing failure and feedback instability might happen when the partial sensors of a satellite attitude control sys- tem (SACS) go wrong. A fault diagnosis and isolation (FDI) method based on a fault observer is introduced to detect and isolate the fault sensor at first. Based on the FDI result, the object system state-space equation is transformed and divided into a corresponsive triangular canonical form to decouple the normal subsystem from the fault subsystem. And then the KX fault-tolerant observers of the system in different modes are designed and embedded into online monitoring. The outputs of all KX fault-tolerant observers are selected by the control switch process. That can make sense that the SACS is part-observed and in stable when the partial sensors break down. Simulation results demonstrate the effectiveness and superiority of the proposed method.     

Transforming Adult Learning Through Critical Design Inquiry

Marching toward the 21st century, there are not only drastic changes in global economic and political development, but also in technological advancement and ecological evolution. All of these are intertwined with one another to shape national and societal development in various areas. In the milieu of education, these changes exert great influence on the way we perceive learning and instruction, this in turn calls for a paradigm shift in the way we design learning and instruction. Consequently, calls to critically examine the way we have been designing our learning and instruction have gained more and more attention in the past decade. Since design could help in realizing our visionary ideals, and transforming these ideals into innumerable learning and working contexts, we need to probe into how our learning and instruction could be more creatively and powerfully designed. The author contends that most learners, through the process of critical envision and enaction, could learn to design their own learning, either independently or collectively, through the cultivation of design capacities. In this paper, the author first presents the historical analysis of the theoretical foundations of instructional design, and then takes a critical approach to examining the alternative possibilities of instructional design. Based on the critical perspectives of design, she develops the critical design inquiry by integrating the richness of contemporary critical thinking into that of systems thinking and design thinking. To make the critical design inquiry an educational praxis, rather than just another design theory, the author takes a participatory and collaborative approach to design with a group of adult students. The critical design approach aims at enlightening the adult learners’ inner systems revolution and enriching the outer learning environments through collaborative design engagement. In the final section, the author explicates how the confined roles of instructional designers could be conceptualized through the critical design inquiry.     

Storying Systems: Managing Everyday Flux Using Mode 2 Soft Systems Methodology

This paper examines work with managers who used a narrative approach to systemic thinking. Storytelling is incorporated within Mode 2 SSM involving a flexible approach to the analysis of complex or "messy" situations at work. Mode 2 SSM is presented as a thinking mode by those within the problem situation, involving the use of various devices of rich pictures, relevant systems, and root definitions, whereby managers and others may make sense of their experiences from within the flux of everyday life. The focus of the approach is learning through reflection on events and activities to consider potential actions and improvements in difficult situations. The findings show the initial difficulty and disappointment of learning to deal with complexity and the unexpected but how quickly the "gain outweighs the pain," as managers learned to attune themselves to the flux of situations, to identify how to work with flows and energies more creatively, and to become conscious of what was happening on the edge of awareness.     

Control in the National Health Service

This paper reviews the objectives behind the installation of control systems within the National Health Service. It outlines how the introduction of market concepts in the National Health Service necessarily changes the objectives of the service and hence its control systems, particularly its financial control systems. The paper then examines various control models, to establish exactly what elements are being controlled and to diagnose some of the shortcomings of the existing system. In conclusion, the authors point to the need for a recognition of multiple (and often conflicting) objectives and for more open debate about the appropriateness of the current simplistic measures to overcome the danger that the faults of the original control system will emerge again, with an emphasis on inputs into the system rather than outputs.     

应用虚拟现实技术建立远程教学系统

远程教学在最近几年有突飞猛进的发展,基于因特网的远程教学系统层出不穷;但是目前推出的远程教学系统及一般网上教学系统,一个重要的缺陷就是无法使用户得到在校园里学习的感受和氛围,由此影响了用户使用这些远程教学系统的兴趣。本文依据虚拟现实的概念和技术,提出一种建立在虚拟校园上的远程教学系统,用户可以在虚拟校园里散步、选择教学楼、选择上某课程的教室、选择实验用具、与同学讨论等,使得用户在这样虚拟学校进行学习活动时,能够更融入虚拟环境所营造出来的学习氛围。本系统利用Virtual Reality、HTML、ASP、CGI及Java等技术实现。     

A Review of Diagramming in Systems Practice and How Technologies Have Supported the Teaching and Learning of Diagramming for Systems Thinking in Practice

The educational process arguably involves a mediated discourse between teachers and learners to aid sense or meaning making for both parties. That mediation, particularly in distance teaching models, is often done through the use of educational resources, whereby teachers develop and/or select the educational resources which the learners then study or engage with through purposeful activities. Some issues or topics are so complicated or complex that words or numbers may be insufficient to represent the meanings contained within them and this is particularly relevant to systems studies which examine complex adaptive systems. Equally diagrams can break out of the linear and systematic nature of printed text to show non-linear and systemic features. This latter trait has been enhanced through the emergence in recent years of digital technologies whereby hypertext and other web applications now make it easier to create dynamic and/or interactive diagrams. And yet there has been little recent research into the influence of such technologies on the learning of systems diagramming skills at a distance. These issues are examined through a review of the literature and the reporting of previously unpublished surveys within The Open University on the value of diagrams to systems studies and the role of technology in influencing the study of diagramming in the teaching of systems thinking in practice. This review indicates that diagrams are seen as an important feature of systems studies and that digital technology can be effective in supporting the teaching and learning of systems diagramming skills at a distance. It also notes that new investigations are needed to examine whether more recent developments in digital technologies have made them more effective and/or efficient for teaching and using such skills in practice.     

Identifying and incorporating change in information systems

The difficulty of identifying future requirements and the inflexibility of information systems make what is normally called the maintenance process difficult and costly, and may lead to information systems failure or obsolescence. This paper addresses the problem in a number of ways. It discusses three techniques which might be used to help identify future requirements. Two of these techniques are drawn from other disciplines; the third is not used widely in the information systems domain. All the techniques have broader applicability than maintenance alone, in that they are concerned with reducing uncertainty. The paper outlines some tenets of good applications software design, drawn from a number of sources, which will facilitate change by making the software design more flexible. Finally, these tenets are incorporated into information systems design through a proposed modification of the information systems life cycle framework. This framework—part of a “code of good practice” for information systems developers—could be incorporated into information systems development methodologies.     

Peirce and Beer

This paper considers the philosophical background of Stafford Beer's Viable Systems Diagnosis (VSD) as profoundly influenced by Charles Peirce. In a general sense, our work discusses the VSD theory base in the development of a model for actionable theory in organizations. This paper examines VSD theory in the Beer trilogy ‘Brain of the Firm,’ ‘The Heart of the Enterprise’ and ‘Diagnosing the System’ and we propose that a sound set of VSD action principles can be derived from this trilogy. We contend that the philosophical background underpinning these principles is important. Using Beer’s ‘Decision and Control,’ we consider that philosophical background and link Operational Research and the interdisciplinary learning within Cybernetics to modern general systems theory. We explore Beer’s viewpoint on the Peirce depiction of four main methods of fixing belief; tenacity, authority, a priori and finally the scientific to assist in that expansion. We consider how knowledge of Beer’s perspective on making sense of the world is important in the linkage of VSD theory to the managerial problem arena. We relate the Peirce methods to previously reported problem solving exercises involving the VSD ideology, which we will develop individually at a later date. This paper reflects our desire to express the interpretation of VSD theory in a language that the well-informed manager may readily translate into the third step of testing theory in practice.     

汉语依存句法网络的复杂网络性质

基于大规模语料库,建立了汉语依存句法网络,并从复杂网络的角度对该网络进行了系统的实验考察.实验结果表明汉语依存句法网络具有复杂网络的两个基本性质:小世界效应和无标度特性,并在其他方面也体现了复杂网络的重要性质.汉语的这些句法上的统计特性,与捷克语、德语和罗马尼亚语等极为相似,说明虽然不同语言有着极为不同的句法规则,但它们具有类似的统计特性,这种共性对人类语言本质的研究具有一定的启发意义.     

从风险管理视角解析中航油事件

从风险管理的角度对中航油(新加坡)事件进行了较为全面的分析.在定性方面,对中航油(新加坡)事件主要的风险来源,如道德风险,市场风险,以及操作风险等,进行了归纳,并构造了一个风险循环模型用于解析此次事件的风险演进过程.在定量方面,运用风险值(Value-at-Risk,VaR)技术对中航油(新加坡)事件中的市场风险做了实证估算用以说明中航油在决策上的大胆与草率.在以上的分析和计算的基础上,对国有海外企业的风险监管和内控提出几个相应的政策建议.     

原材料采购问题的占线竞争策略分析

研究的是价格不确定条件下的原材料采购问题.在实际的原材料采购决策中,经常会遇到如下情形:特定时间内某原材料的价格随时间的变动具有不可预期性,同时该原材料具有固定的需求消耗.为了最小化采购费用,我们需要在满足需求的条件下确定在什么时间,以什么价格以及采购多少的决策问题.以往的研究一般都是假设采购价格是随机波动的,而实际情况中价格常常是不可随机观测的.本文从占线理论出发考虑了原材料占线采购问题,设计了一个竞争策略,证明了相应的竞争比,该竞争比结果优于已有结果.     

基于Vega Prime的航天器视景仿真中的多坐标系问题

正确理解、掌握和综合运用多种坐标系统是航天器视景仿真开发过程中至关重要的基础所在，也是开发过程中较大的一个难点。首先对航天器视景仿真中经常使用的坐标系统进行了分析，然后蛤出了在VegaPrime环境中定义、创走和使用不同坐标系的方法，最后还给出了不同坐标系间位置和姿态数据的转换方法。文中给出的开发思路对于远程导弹、运载火箭、人造卫星等各类航天器的视景仿真开发都具有很高的通用性和实用性。     

双寡头有限理性广告竞争博弈模型的复杂性分析

对有限理性动态古诺模型进行了改进,并将其引入到广告市场中,同时也综合考虑了广告成本和生产成本的影响,使得该模型更加符合实际.在此基础上,对改进后的模型的演化过程进行了分析,指出了Nash均衡的稳定区域及其影响因素.通过理论分析和数值模拟计算研究模型中各参数的变化情况,发现当企业为获取前期的竞争优势,而加快广告投入量的调整速度和提高单位广告所产生的平均需求时,将会导致系统的不稳定,从而使系统陷入混沌状态这一经济现象.     

Sampling Dependent Stability Results for Aperiodic Sampled-Data Systems

This paper investigates sampling dependent stability for aperiodic sampled-data systems by employing a Lyapunov-like functional that is time-dependent, and not imposed to be definite positive.Based on the system information on the sampling interval wholly rather than partly, a new Lyapunovlike functional is constructed, which extends existing ones by introducing the integral of the system state and the cross terms among this integral and the sampled state. To take advantage of the integral of the system state, integral equations of the sampled-data system are explored when estimating the derivative of the extended functional. By the Lyapunov-like functional theory, a new sampling dependent stability result is obtained for sampled-data systems without uncertainties. Then, the stability result is applied to sampled-data systems with polytopic uncertainties and a robust stability result is derived. At last,numerical examples are given to illustrate that the stability results improve over some existing ones.     

基于系统工程的系统分类法及应用

首先叙述了一般文献中对系统的分类，然后对钱学森为首的一批知名学者关于系统的人和了介绍。详细地讨论了Ｓｈｅｎｈａｒ和Ｂｏｎｅｎ对系统的二维分类法，并同钱学森的系统分类法进行联系，根据２－Ｄ分类法，提出了系统开发的三维结构，最后对其应用实例进行了说明。     

Human inquiry: Steps towards emancipatory practice

In this paper we explore the contribution of work in Human Inquiry to the debate about what might constitute authentic emancipatory practice and about how such an ideal might be approached. We beghin by considering some key values, issues, and commitments which characterise this work and distinguish it from other established research traditions. A number of distinct approaches to the practice of human inquiry have been articulated. These are referred to but it is not our purpose to review particular approaches in detail here. Rather our aim is to move from this overview of human inquiry to consider some important implications for practice. In particular, we look at Bateson's theory of levels of learning and explore ways in which both the intellectual and the more personal frameworks of participants can contribute to, and at times impede, the kinds of mutual learning with which human inquiries are concerned. We illustrate this discussion by drawing on examples from our own work in human inquiry. Here we aim to highlight particular implications and issues that might arise within human inquiries. One source of illustrations is Peter's work with general and complementary practitioners in a primary health care centre, the other is Anne's work with UWE student groups acting as consultants for local community organisations. In each case we consider some origins, forms, and expressions of power differences and show how empowerment can occur as participants learn within and across Bateson's levels as inquiries progress. We conclude by summarising the evidence of and opportunities for empowerment in each case and by showing how a deeper appreciation of Bateson's levels of learning can further understanding of the nature of emancipatory practice. Finally, we make more general suggestions about the role of approaches to Human Inquiry in future emancipatory practice.     

Model Reference Adaptive Control for Networked Distributed Systems with Strong Interconnections and Communication Delays

In recent years, networked distributed control systems (NDCS) have received research attention. Two of the main challenges that such systems face are possible delays in the communication network and the effect of strong interconnections between agents. This paper considers an NDCS that has delays in the communication network, as well as strong interconnections between its agents. The control objective is to make each agent track efficiently a reference model by attenuating the effect of strong interconnections via feedback based on the delayed information. First, the authors assume that each agent knows its own dynamics, as well as the interconnection parameters, but receives information about the states of its neighbors with some communication delay. The authors propose a distributed control scheme and prove that if the interconnections can be weakened and if the communication delays are small enough, then the proposed scheme guarantees that the tracking error of each agent is bounded with a bound that depends on the size of the weakened interconnections and delays, and reduces to zero as these uncertainties reduce to zero. The authors then consider a more realistic situation where the interconnections between agents are unknown despite the cooperation and sharing of state information. For this case the authors propose a distributed adaptive control scheme and prove that the proposed scheme guarantees that the tracking errors are bounded and small in the mean square sense with respect to the size of the weakened interconnections and delays, provided the weakened interconnections and time delays are small enough. The authors then consider the case that each agent knows neither its dynamics nor the interconnection matrices. For this case the authors propose a distributed adaptive control scheme and prove that the proposed scheme guarantees that the tracking errors are bounded and small in the mean square sense provided the weakened interconnections and time delays are small enough. Finally, the authors present an illustrative example to present the applicability and effectiveness of the proposed schemes.     

Workplace Logics, Kinds of Knowledge and Action Research

Workplace logics signify attitudes that employees express in close interaction, formal decision-making and collaborative interventions. The term covers a metaphorical mental context rather than a mathematically coherent understanding of social control mechanisms that influence interlocutors in cooperative activity. Workplace logics relate to future-oriented choices that employees make so as to obtain targeted production goals. But logics also hold an explanatory potential. They enable for the researcher to account for social systems that need to be designed before they are acted on. The objective for analysing workplace logics is to turn attention away from language and focus on activity systems. Successful action research facilitates for individual and organizational learning, the latter of which is rarely fulfilled in contemporary research.     

复杂经济系统的空间动态建模方法

提出了市场经济条件下复杂经济系统空间动态建模方法。这一建模方法强调经济活动中区域的复杂性和部门的关联性，通过“吸引”概念（需求吸引、移民吸引和投资吸引等），建立模型系统的反馈机制和自组织，探索系统结构演化的空间动态行为。最后以某国１９８０－１９９０年的历史数据校验模型，研究了该国１９９５和２０００年经济结构演变的趋势。