Usage of SoS methodologies in production system design

Production systems design is a multifaceted task, due to a variety of aspects such as the mutual interdependency between the sub-systems, the variety of configurations and alternative system control strategies, the multiple managerial and “soft” aspects that cast an influence on the behavior of the system. A reasonable number of modeling tools can be applied to production system design, but they tend to divide the problem into unconnected sub-problems whose individual solutions may result in a poor global one. This is despite the fact that production design encompasses all aspects of manufacturing operations, and needs a systemic approach, as clearly shown in practitioner-oriented literature. This paper proposes to apply the “System of Systems” approach to production system design in order to represent their main aspects and support the rational definition of the path leading from corporate strategy to system (re)design.     

The use of task modeling in interactive system specification

Cognition, Technology & Work - Task modeling is undoubtedly a key step for task analysis during the development of iterative systems since it helps not only in the understanding of what users...     

基于柔性的网络化教务管理系统模型的构建

随着互连网应用的发展,人们越来越多地把教务管理过程放到网络上来,而不再局限于传统的办公室管理,因此基于Web的教务管理得到了迅速推广.为了有效解决教务管理系统动态适应用户需求变化的问题,结合柔性的思想,提出基于柔性的网络化教务管理的概念,并给出了实现基于柔性的网络化教务管理系统的具体思路和解决方案.基于柔性的网络化教务管理将成为教务管理的新模式.     

The use of systems development methodologies in practice: a field study

This paper discusses the findings of a field study of experienced systems developers which investigated the use of systems development methodologies (SDMs) in practice. Among the main findings to emerge are the following. There is a wide difference between the formalized sequence of steps and stages prescribed by a methodology and the methodology-in-action uniquely enacted for each development project. Also, there is much evidence which suggests that developers omit certain aspects of methodologies not from a position of ignorance, but from the more pragmatic basis that certain aspects are not relevant to the development environment they face. Thus, methodologies are tailored to the needs of the prevailing development environment and, being documented in a single manual often, are framed at a higher level of granularity that specifies broad activities and objectives, rather than specifying in a very detailed fashion the exact manner in which development should take place. Additionally, the findings clarify the apparently contradictory position in the literature as to whether developer experience is positively or negatively correlated with methodology use. The study would suggest that experienced developers are likely to use methodologies, albeit ones which have been heavily customized to the exigencies of the particular situation.     

Intelligent multiagent application system in an AI system

This article presents an intelligent multiagent application system in AI. The research trend into multiagents is changing from a centralized computing environment to a distributed computing environment. Also, the research into multiagents can be changed to a mobile environment. Initially, the study of multiagents is from research into human modeling. Therefore, we fi rst present a brief concept of a mobile multiagent, and then we present some application areas for mobile multiagents, especially in elearning, bioinformatics, control, and information retrieval, etc. Finally, we present the research theme of multiagents in AI. This work was presented in part at the 12th International Symposium on Articial Life and Robotics, Oita, January 25–27, 2007     

Rationality concepts in information system development methodologies

The purpose of this paper is to demonstrate that current practices and theories of information systems development (ISD) could benefit from a more explicit consideration of concepts of rationality. Many ISD methodologies already pay some attention to more than one rationality concept but they often do not fully recognize this, fail to strike a proper balance between them, and consequently fall short in cases where system success depends on a rationality concept that is not well catered for in a particular methodology. This paper explores four rationality concepts (formal, substantive, communicative, and emancipatory) and their implementation in seven ISD methodologies. The first two rationality concepts are drawn from Max Weber's “theory of organization” and the latter two from the “critical social theory” of Jurgen Habermas.     

基于UML-RT的复杂嵌入式系统建模方法及其应用

分析了UML在实时系统设计中的优点和需要解决的主要问题,论述了基于UML RT的实时嵌入式系统设计方法,并且对其进行扩展以支持数据流计算模型的建模,最后以汽车巡航系统为例加以说明。     

Methods of maintenance: Piecemeal use of structured methodologies

Structured methodologies, intended by their designers for new systems development, can be applied to the maintenance of existing implemented systems. Although there is much scope for improvement in the structured tools and techniques as they exist at present, there are still potential benefits to be gained by using them to ease the present maintenance ‘burden’.     

Top-down vs bottom-up methodologies in multi-agent system design

Traditionally, two alternative design approaches have been available to engineers: top-down and bottom-up. In the top-down approach, the design process starts with specifying the global system state and assuming that each component has global knowledge of the system, as in a centralized approach. The solution is then decentralized by replacing global knowledge with communication. In the bottom-up approach, on the other hand, the design starts with specifying requirements and capabilities of individual components, and the global behavior is said to emerge out of interactions among constituent components and between components and the environment. In this paper we present a comparative study of both approaches with particular emphasis on applications to multi-agent system engineering and robotics. We outline the generic characteristics of both approaches from the MAS perspective, and identify three elements that we believe should serve as criteria for how and when to apply either of the approaches. We demonstrate our analysis on a specific example of load balancing problem in robotics. We also show that under certain assumptions on the communication and the external environment, both bottom-up and top-down methodologies produce very similar solutions.

The influence of modeling hypothesis and experimental methodologies in the accuracy of muscle force estimation using EMG-driven models

This paper discusses some methodological questions regarding the application of EMG-driven models to estimate muscle forces, for the triceps surae performing isometric contractions. Ankle torque is estimated from a Hill-type muscle model driven by EMG data, collected from the three components of triceps surae and tibialis anterior. Ankle joint torque is synchronously collected from a dynamometer, which is compared to the sum of each muscle force multiplied by the respective ankle moment arm. A protocol consisting of two steps of low and medium/high loads is used. Raw EMG signal is processed and used as the input signal for the muscle model. The difference between simulated and dynamometer measured torque is calculated as the RMS error between the two curves. A set of nominal muscle model parameters is initially chosen from literature (e.g., OpenSim), which allows observing the characteristics of the error distribution. One possibility to improve model accuracy is using individual muscle parameters. We investigated the effect of applying simple scale factors to the nominal muscle model parameters and using ultrasound for estimating muscle maximum force. Other questions regarding muscle model improvements are also addressed, such as using a nonlinear formulation of activation dynamics and variable pennation angle. Surface EMG signals acquisition and processing can also affect force estimation accuracy. Electrodes positioning can influence signal amplitude, and the one-channel EMG may not represent actual excitation for the whole muscle. We have shown that high density EMG reduces, in some cases, the torque estimation error.     

A knowledge-based system for selecting test methodologies

A prototype knowledge-based system that helps select test methodologies for a particular type of logic structure is described. The system, called TDES, (testable design expert system), is a subsystem of Adam, an advanced design automation system. The system is being used to test programmable logic arrays, but its architecture is applicable to other types of structures such as RAMs, ROMs, and other combinational logic. It uses a divide-and-conquer (partitioning) strategy and works interactively with a user as an intelligent consultant and assistant     

基于Europa2的智能规划动态仿真与建模

仿真与建模是智能规划(特别是时态规划)走向应用的重要而困难的研究主题。目前已有的规划可视化建模工具只能支持领域无关的仿真和建模,无法模拟现实场景。基于时间线的Chronicle规划与Microsoft最新的图形显示技术WPF在某些概念上存在自然的对应关系。基于这样的思想,针对NASA开发的开源时态规划平台——Europa2,使用WPF基础类库和相关工具,研究智能规划能够模拟现实场景的动态仿真和建模的设计方法并给出了实例演示。研究表明,对诸如Europa2一类基于时间线的Chronicle规划系统,可以应用WPF一类通用图形技术进行方便的建模和动态仿真,从而初步解决了规划系统模拟现实场景的仿真和建模难以实现的问题。     

The intelligence left in AI

In its forty years of existence, Artificial Intelligence has suffered both from the exaggerated claims of those who saw it as the definitive solution of an ancestral dream — that of constructing an intelligent machine-and from its detractors, who described it as the latest fad worthy of quacks. Yet AI is still alive, well and blossoming, and has left a legacy of tools and applications almost unequalled by any other field-probably because, as the heir of Renaissance thought, it represents a possible bridge between the humanities and the natural sciences, philosophy and neurophysiology, psychology and integrated circuits-including systems that today are taken for granted, such as the computer interface with mouse pointer and windows. This writing describes a few results of AI that have modified the scientific world, as well as the way a layman sees computers: thetechnology of programming languages, such asLISP-witness the unique excellence of academic departments that have contributed to them-thecomputing workstations-of which our modern PC is but a vulgarised descendant-theapplications to the educational field-e.g., the realisation of some ideas of genetic epistemology-and tointerdisciplinary philosophy-such as Hofstadter's associations between the arts and mathematics-and the use ofAI techniques in music and musicology. All this has led to a generalisation of AI towards Negrotti's overallTheory of the Artificial, which encompasses further specialisation such asartificial reality, artificial life, and applications ofneural networks among others.     

A graphical interface for production and transportation system modeling: PTS

PTS is a graphical interface for production and transportation system modeling. It provides a means of creating an economic model of production and transportation activities in a system of plants and markets. The model created by PTS is translated into the GAMS language and is solved using that system. The results are then returned to PTS and are displayed graphically. PTS runs under Windows on IBM PCs and compatibles. PTS is used to (1) provide a graphical interface for knowledge-based model development systems, (2) provide a test-bed for studies of parallel model representations and (3) analyze methods of production and transportation model development which are simpler than the knowledge-based methods. The system is currently implemented for linear programming production and transportation problems. Also, the current implementation provides graphical and GAMS representations of the model.     

The Future of AI in Space

Two key flight technology experiments--the Remote Agent Experiment (RAX) and the Autonomous Sciencecraft Experiment (ASE)--validated appropriate uses of AI-based capabilities in future robotic and human exploration of the Moon, Mars, and beyond. A survey of future missions describes some of them.     

Utilizing knowledge links in the implementation of system development methodologies

Developing technical ‘know-how’ is a slow process that can become a barrier in implementing complex administrative technologies such as a software development methodology. To overcome this barrier, organizations often seek knowledge links that can enhance learning and minimize inevitable problems that are encountered in an implementation process. This paper presents the findings of an empirical study that examines the prescribed versus actual use of external consultants, universities and vendors as knowledge links during the implementation of systems development methodologies (SDM). First, the study assesses the need and value of establishing and utilizing links to external sources of expertise for successful SDM implementation. We then identify and analyze a gap that exists between what the links to external knowledge are perceived to be capable of contributing and what the links to external knowledge are actually contributing during SDM implementation. In conclusion, possible reasons for the gap are discussed.     

Simulation of a production line system with machine breakdowns using network modeling

In a manufacturing system, several factors can affect the reliability of the system in producing expected output levels, including resource input rates, labor rate variability, product quality, and machine failures. Although all of these factors will be reflected in the modeling process presented in this paper, the primary focus will be on the effect of machine breakdowns on system output. Network modeling and simulation with Q-GERT is the vehicle of analysis that is employed. This technique will be demonstrated via a realistic case example encompassing a complex production system consisting of several assembly lines, each containing several machines. The statistical results of the simulation of the example system are presented and discussed. In addition, examples of how the simulation model can be used to test changes in machine repair times and breakdown rates will be presented.