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 use of AI methodologies in production system modeling

Managers of production facilities encounter substantial complexities when attempting to utilize formal mathematical methods to support their planning activities. These complexities arise from difficulties in the formulation of production models, their execution via computer based methods, and the interpretation of the results obtained. This paper demonstrates a practical method for providing managers with the tools necessary to deal with these complexities. The method is based on the representation of modeling knowledge via formal logic and its implementation via Prolog.     

Cost-benefit analysis of data warehouse design methodologies

Methodologies for data warehouse design are increasing more and more in last years, and each of them proposes a different point of view. Among all the methodologies present in literature, the promising ones are the hybrid methodologies—because they represent the only way to ensure a multidimensional schema to be both consistent with data sources and adherent to user business goals—and those able to support the designer by providing some kind of automation. However, the results obtainable by the methodologies can differ substantially in terms of schema quality and required efforts. In this paper, we provide metrics for evaluating the quality of multidimensional schemata in reference to the effort spent in the design process and the automation degree of the methodology. As a case study, we apply our evaluation to the major emerging hybrid methodologies for data warehouse schema design.     

弱电混合动力系统的设计与制作

介绍了一种具有启停功能的并联式弱电混合动力系统的解决方案,论述了其在解决汽车的燃油经济性和排放性上的优势。分析了弱电混合动力汽车功能及工作原理,并对怠速启停系统控制策略进行了综述。再对弱电混合动力汽车主要参数进行分析,根据制作要求选择设计制作要求选择动力组件和其他配件所需参数,结合结构方案与控制动力策略制作试验车。     

Evaluation criteria for logical database design methodologies

The increasing acceptance of database systems has shown the need for logical database design methodologies and evaluation criteria to select the one most appropriate for a particular task. Application of currently existing methodologies to a portion of the data handled during chemical process plant design has highlighted strengths and shortcomings of the methodologies analysed. Using these results, evaluation criteria are established and synthesis of a methodology which is responsive to the identified criteria is proposed.     

Object-oriented and conventional analysis and design methodologies

Three object-oriented analysis methodologies and three object-oriented design methodologies are reviewed and compared to one another. The authors' intent is to answer the question of whether emerging object-oriented analysis and design methodologies require incremental or radical changes on the part of prospective adopters. The evolution of conventional development methodologies is discussed, and three areas-system partitioning, end-to-end process modeling, and harvesting reuse-that appear to be strong candidates for further development work are presented     

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.     

Impact of design-manufacturing interface on SoC design methodologies

Today's semiconductor manufacturing trends are increasingly influencing hardware design techniques, tools, and methodologies. We analyze these trends and describe their effects on design methodologies. These effects clearly include impacts on yield optimization resolution enhancement.     

Simulation and design of a dual-kanban production system

A procedure to evaluate system design parameters for “pull” production strategies is presented in this paper. The evaluation procedure is based on a cost function which includes the inventory carrying, storage, setup, stockout, and idle costs. A combined SLAM II/FORTRAN simulation model and electronic spreadsheets support the evaluation procedure. A “pull” production strategy using the dual-kanban production control method is modeled. The best design in terms of unit load size/number of kanbans is found to (a) satisfy daily production requirements and (b) minimize the cost function.     

Variability detection and robustness design in complex production system

This paper will study the detection of variability and the techniques of robust design in complex production system consisted of many processes with close correlativity. First, the background of variability detection in production system is introduced, and then a weighted network corresponding to correlation matrix of all processes is set up. Based on the network and clustering criterion of maximum spanning tree, a classification of all processes is derived. Further, the variation of each process in a class is determined by residual analysis. Finally, the methods of robust design that can be effectively conducted for the processes with large variability are discussed.     

Structure-based combinatorial library design: methodologies and applications

Rational design of small focused libraries that are biased toward specific therapeutic targets is currently at the forefront of combinatorial library design. Various structure-based design strategies can be implemented in focused library design when the 3D structure of the target is available through X-ray or NMR determination. This review discusses the major methods and programs specifically developed for the purpose of designing combinatorial libraries under the constraint of the binding site of a biological target, with emphasis on their advantages and disadvantages. Examples of the successful application of these methodologies are highlighted, demonstrating their performances within the practical drug discovery process.     

Program design methodologies and the software development process

This research examined program design methodologies which claim to improve the design process by providing strategies to programmers for structuring solutions to computer problems. In this experiment, professional programmers were provided with the specifications for each of three non-trivial problems and asked to produce pseudo-code for each specification according to the principles of a particular design methodology. The measures collected were the time to design and code, percent complete, and complexity, as measured by several metrics. These data were used to develop profiles of the solutions produced by different methodologies and to develop comparisons among the various methodologies. These differences are discussed in light of their impact on the comprehensibility, reliability, and maintainability of the programs produced.     

Information systems design methodologies - A comparative review

The IFIP WG 8.1 Working Conference (WC) on Comparative Review of Information Systems Design Methodologies was held in Noordwijkerhout, The Netherlands from May 10–14, 1982. This major IFIP event was chaired by Alex Verrijn-Stuart, Bill Olle and Henk Sol, who were able to organize an illuminating and interesting program.     

The adoption and design methodologies of component-based enterprise systems

One of the major investments of information technologies in large companies in the past decade has been the enterprise system. Although the enterprise system has the advantages of managing and integrating almost all of the business processes in the whole company, there have been strong criticisms that the enterprise system often imposes its own logic or business process on a company and lacks flexibility and adaptability in today's dynamic business environment. The goal of this paper is to outline a new approach in enterprise system development. We analyse the factors that affect the adoption of enterprise systems. Market and business changes, and advances in information technologies call for a more flexible, open, and scalable enterprise architecture. We describe the process that Dell Computer Corporation took in adopting its component-based enterprise system architecture. The Dell example has demonstrated the importance of fit between business information systems and fundamental organizational dimensions of the company including strategy, business environment, and organizational structure. We also discuss the design methodologies for component-based enterprise system design. We take a coordination perspective, both at the software level and the organizational level, in addressing the design methodologies for component-based enterprise system development.     

Analytical approach for function oriented production system design

For planning complex manufacturing systems advanced modelling techniques are required. Process-independent functional units facilitate a fast model implementation and expand the area of applicability. Alternatives in system structuring and criteria for procedural design in a wide area of potential solutions are described. Requirements for functional modelling and practical implementation examples illustrate the approach.     

Mean station reliabilities cause throughput overestimates in production system design

In production system design, we typically lack actual station reliability data for throughput analysis using a model, because these stations do not yet exist. Hence, we either use the mean values from similar existing equipment or mean reliability estimates provided by equipment manufacturers. The real stations may have better or worse reliabilities compared to the means. Hence, when the system is built, the real system throughput may be acceptable or poor depending on actual station reliabilities. This paper compares predicted model throughput using station mean reliabilities with real system throughput. We find that the model often overestimates system throughput. We develop an upper bound and the maximum probability of overestimation when there is an infinite buffer size after each station. We also provide the ranges of overestimation for systems with limited buffers. These results may be used as a “rule of thumb” to adjust system throughput estimation. Monte Carlo simulation is discussed as an approach to analyze real system performance.     

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