Abstract: The state of object-oriented is evolving rapidly This survey describes what are currently thought to be the key ideas Although it is necessarily incomplete, it contains both academic and industrial efforts and describes work in both the United States and Europe It ignores well-known ideas, like that of Coad and Meyer [34], in favor of less widely known projectsResearch in object-oriented design can be divided many ways Some research is focused on describing a design process Some is focused on finding rules for good designs A third approach is to build tools to support design Most of the research described in this article does all threeWe first present work from Alan Snyder at Hewlett-Packard on developing a common framework for object-oriented terminology The goal of this effort is to develop and communicate a corporate-wide common language for specifying and communicating about objectsWe next look into the research activity at Hewlett-Packard, led by Dennis de Champeaux De Champeaux is developing a model for object-based analysis His current research focuses on the use of a trigger-based model for inter-object communications and development of a top-down approach to analysis using ensemblesWe then survey two research activities that prescribe the design process Rebecca Wirfs-Brock from Tektronix has been developing an object-oriented design method that focuses on object responsibilities and collaborations The method includes graphical tools for improving encapsulation and understanding patterns of object communication Trygve Reenskaug at the Center for Industriforskning in Oslo, Norway has been developing an object-oriented design method that focuses on roles, synthesis, and structuring The method, called Object-Oriented Role Analysis, Syntheses and Structuring, is based on first modeling small sub-problems, and then combining small models into larger ones in a controlled manner using both inheritance (synthesis) and run-time binding (structuring)We then present investigations by Ralph Johnson at the University of Illinois at Urbana-Champaign into object-oriented frameworks and the reuse of large-scale designs A framework is a high-level design or application architecture and consists of a suite of classes that are specifically designed to be refined and used as a group Past work has focused on describing frameworks and how they are developed Current work includes the design of tools to make it easier to design frameworksFinally, we present some results from the research group in object-oriented software engineering at Northeastern University, led by Karl Lieberherr They have been working on object-oriented Computer Assisted Software Engineering (CASE) technology, called the Demeterm system, which generates language-specific class definitions from language-independent class dictionaries The Demeter system include tools for checking design rules and for implementing a design

Abstract: This paper was invited by the editors of this Journal in response to an informal presentation the author made to the 1990 NSF Design and Manufacturing Research Conference [NSF]. It comprises the author's opinions and does not constitute research. The author's background is a mix of academic and industrial, with less emphasis on theory in the abstract and more on methods responsive to an identified need. The author believes in \"design theory\" but the reader will find different elements, emphases, and priorities in this paper than are customary in past treatments (for example, [ASME, Spillers and Newsome]). The editors expressed a desire that this alternate view be presented in the journal to encourage debate and discussion.

Abstract: An electrical design system is described which integrates many analysis and synthesis tools in an environment of top-down circuit layout. The system allows electrical design in numerous technologies, including nMOS, CMOS, bipolar, printed circuit boards and others. Technologies and analysis or synthesis tools may be added or deleted easily, and different technologies may be employed in a single design. The system includes a database manager which maintains all information regarding the design of the circuit, and which is accessed by all of the analysis and synthesis tools to enable them to examine and modify the design. The database itself is structured as a network of electrically connected and geometrically described components. Each component in the database is considered a node, and connections among components are considered as arcs. Changes are permitted only to nodes, and constraints are imposed only upon arcs. When components are changed, the effects of the changes are propagated to surrounding components by the arcs. In this manner the database manager insures that the circuit remains properly connected throughout the design process while allowing the propagation of changes up and down the hierarchy.

Abstract: High-level synthesis is the transformation from a behavioral level specification of hardware, through a series of optimizations and translations, to an implementation in terms of logic gates and registers. The success of a high-level synthesis system is heavily dependent on how effectively the high-level language captures the ideas of the designer in a simple and understandable way. Furthermore, as system-level issues such as communication protocols and design partitioning dominate the design process, the ability to specify constraints on the timing requirements and resource utilization of a design is necessary to ensure that the design can integrate with the rest of the system. In this paper, a hardware description language called HardwareC is presented. HardwareC supports both declarative and procedural semantics, has a C-like syntax, and is extended with notion of concurrent processes, message passing, timing constraints via tagging, resource constraints, explicit instantiation of models, and template models. The language is used as the input to the Hercules High-level Synthesis System.

Abstract: Research on the design of end-user applications has focused on methods for empirically determining user requirements, and for managing usability in the design process by analogy with the management of functionality. As an alternative to this approach, the authors propose that both sorts of design considerations be combined in a more comprehensive, task-oriented representation. End-user applications should be represented in the design process as a set of typical and/or critical user-interaction scenarios. An example of this approach is applied to the design of a new inspector for Smalltalk. >

Abstract: Because of their characteristic attributes of combining factual knowledge with judgment, being able to handle incomplete and uncertain data, and communicating with their users in the natural langua...

Abstract: Water distribution networks, like other engineering systems, are subjected to random.failures. The failures may occur in the elements of the network (mostly pipes) or in the nodes (pipe junctions and demand nodes). Since a breakdown in water supply is not acceptable for more than a few hours, the network should be invulnerable to some extent, that is, it must include several independent alternatives of water supply to every consumer. Adopting an invulnerability degree of two alternative supplies, a new methodology is presented for the least-cost design of water distribution networks. According to this methodology the design process is controlled by the designer via three distinct stages. In the first stage the alternative paths are allocated using graph theory algorithms. In the second stage the minimum hydraulic capacity (diameters) of each path is determined using a linear programming model, and in the third stage the solution is tested by a network solver for various demand patterns. An exampl...

Abstract: A: Introduction.- 1. Overview.- 2. Flexible manufacturing systems.- 3. Planning problems of flexible manufacturing systems.- B: Analyzing the Design Process.- 4. The design process.- 5. A concept for the design process.- C: Tools and Models.- 6. Tools for the design process.- 7. Modelling the basic planning stage.- 8. Models for the optimal design of flexible manufacturing systems.- 9. Conclusions and directions for further research.- Appendix C: Consideration of demand under risk and uncertainty.- Appendix D: Test runs for model EQUP-NEW-(1).- Appendix E: List of figures, tables, algorithms.- Appendix F: Abbreviations, journals, definitions of indices, parameters and variables.- References.

Abstract: A methodology for studying and understanding the process of design, and ultimately for developing a computational theory of design is presented. In particular, the role of formalization in such an investigation is set out. This is done by first presenting the background to and development of computational search as a widely adopted problem solving paradigm in artificial intelligence research. It is then suggested why computational search provides an inadequate characterization of the design process and an alternative, that design is an exploration process is proposed. By developing certain ideas first put forward by Simon the authors seek to explain why this view is taken and how it forms a central part of their Artificial Intelligence in Design research programme. It is hoped to (eventually) develop a computational theory of design. The radically incomplete nature of this work necessarily prevents the authors from answering the question posed by the title of the paper but the title does provide a good focus for their efforts.

Abstract: Although available technology may be inadequate for the complete remediation of certain contaminated ground water‐sites, hydraulic control can be used to reduce the extent of, and contain, ground‐water contaminants until adequate technology can be developed. The design of such a remediation system can be viewed as a two‐stage process. A first stage is the achievement of a reduction of the extent of the contaminant, and a second stage is the maintenance of the contaminant at this reduced areal extent. Viewed in this light, alternative pump staging criteria can be considered within the design process. These criteria can include allowing the well location and pumping rate to change during the remediation effort. This paper analyzes the economic significance of incorporating increasing complexity of pump‐stage criteria into the design process. The analysis is conducted using numerical simulation and a new multistage optimization formulation. The analysis concludes that while different pumping strategies shoul...

Abstract: Although many aids for the disabled appear to be quite simple, their design is subject to many difficulties. These problems arise because of the intimate relationship between the equipment and the human body. Equipment design is therefore affected by many biological variables that are difficult to define at the beginning of the design exercise and many will not even be obvious until a device is tried out with a user. Standard design methodologies rely on all the variables being defined in a thorough specification at the start of the design process and therefore often lead to ineffective devices or very long development programmes. An alternative methodology is presented which overcomes the problems by separating the user interface aspects of the design from the supporting features. The user interface aspects are then allowed to evolve in conjunction with tests with potential users and finally integrated with the supporting features once a satisfactory solution has been found. Much more effective devices r...

Abstract: To evaluate the effectiveness of built-in self-test (BIST) for logic circuits, the test design automation (TDA) group within the IBM Engineering Design System (EDS) has developed tools to support BIST. This paper is an overview of that support. The specific hardware approaches taken are described briefly, and a short description is given of the major tools that have been developed and the methodology for using them. The performance of the system is shown for two sample circuits.

Abstract: An ongoing research project with a large international manufacturing company has uncovered many critical issues for the development and introduction of systems that supportconcurrent engineering. Several of these issues can be solved through careful interface design, while others require significant technical and organizational changes. To reduce training costs and support a broad spectrum of users, computer system developers must create a single system image, giving the users the impression that they are accessing a single database through a consistent and easy to use interface. This interface, and the tools it contains, may be used to support concurrent engineering activities even when a company is geographically distributed over a large area. The complexity of the firm's products and processes and the need for rapid access to relevant performance information make it essential that developers identify suitable frameworks for organizing database queries.Design hierarchies, representations of the structure and function of the firm's products and processes, have proven to be powerful tools for effective query management, and for efficient navigation through the database. The database interface must also produce integrated displays of data drawn from a number of sources in response to prestructured queries. Beyond these interface design issues, there are a number of technical and organizational barriers to the implementation of large-scale engineering systems. In particular, the existence of many incompatible databases in different parts of an organization makes the introduction of a new, uniform system very difficult. Organizational issues also play a major role in achieving, or hindering, the implementation of new computer systems. This paper describes some of the technical innovations, and the motivations behind them, from one particular engineering design system. It also discusses the reactions of engineers and management, and explains why management may oppose innovation even when engineers enthusiastically support it.

Abstract: The design of a component, its material and method of manufacture determine its quality and cost. In this paper a technique is introduced that can be used in the early stages of the design process ...

Abstract: This paper investigates the integration of simulation with expert systems. Several recent engineering research projects in this field are described. Relevant research in construction is discussed and potential benefits of integrated systems are explored. Integrating simulation with expert systems can produce powerful analytical tools with immediate potential use in construction. A prototype system is developed by integrating an expert‐system shell with a popular construction simulation software. The system developed allows the user to choose suitable earth‐moving equipment (scraper versus truck, shovel versus bulldozer) under a given set of job conditions, select an appropriate simulation file, perform simulation analysis, and output cost and production rates. The expert system acts as an interface between the user and the simulation software. The user can benefit from the power of simulation analysis without having to be a simulation expert. Several issues are identified in the course of system developme...

Abstract: Publisher Summary Central to progress in the design and validation of computer adaptive systems will be the possession of the means to evaluate the performance of this type of system. Apart from the procedures for measuring the total performance of the system—its ability to adapt and to affect behavioral measures—one also requires evaluation procedures that support the design process. These latter procedures will support the diagnosis of the relationship between the design and its performance to improve subsequent design. It is also expected that some of these evaluation techniques will be embodied within the system to allow it to self regulate its performance. This chapter discusses different types of evaluation for human–computer interaction. It discusses some of the special problems of evaluating adaptive systems. The chapter describes a number of different techniques for evaluation that have been developed and used on the Adaptive Intelligent Dialogs (AID) project. It also discusses the application of these techniques during and after the design and construction of a computer adaptive system.

Abstract: The knowledge regarding design flow management is described and modeled by predicate-transition Petri nets and production rules. The approach offers a clear and flexible tool control mechanism within a CAD framework such that both static and dynamic behavior of a design flow are supported. The authors also demonstrate how different forms of knowledge can be implemented by a rule based system, OPS83, and be integrated in the HILDA CAD framework to guide the users through the design process. >

Abstract: CAOS is a system for structural shape optimization. It is closely integrated in a Computer Aided Design environment and controlled entirely from the CAD-system AutoCAD. The mathematical foundation of the system is briefly presented and a description of the CAD-integration strategy is given together with an example.

Abstract: Object-oriented, a buzzword of the late 1980s, has evolved into an accepted technology that has recognized benefits for the software development process. In its progression from a purely procedural approach, software development reached a data-driven—object-based—approach, and has grown beyond that to the object-oriented approach.The impact of the object-oriented approach is not limited to the design portion of the software development life cycle—its effects are evident at every phase. One of the strengths of the object model is that it provides a unifying element that is common to every phase of the life cycle. This uniformity provides a smooth transition from one phase to the next.The article by Henderson-Sellers and Edwards presents a revision of the traditional life cycle based on the object-oriented approach. It discusses the unique view of the design process and describes how it works: the process takes a specified problem and decomposes it. The resulting product forms the framework for a computer-based solution to the problem. Object-oriented techniques begin this decomposition process in the analysis phase and carry it on into the design phase. A modeling paradigm is used for the decomposition process: The top layer of an object-oriented system is a model of the real-life situation for which the software system is being created. The underlying layers provide the implementation of this model.The “pieces” produced by object-oriented techniques are as unique as the design perspective. Its obvious similarities to and subtle differences from abstract data type (ADT) technology have led to much discussion of objects and classes in terms of ADTs. The unique coupling of data and behavior in the object-oriented components provides much more than a syntactic distinction from the usual ADT. Added to the modeling approach, it produces a recognizably different approach to systems development.The term object-oriented is defined differently by different people. Many professionals agree with the basics of Wegner's definition1 that object-oriented includes three concepts: objects, classes, and class inheritance. Some would add a variety of other requirements including such concepts as polymorphism, dynamic binding, encapsulation, etc. The article by Korson and McGregor provides an overview of these concepts, leaving room for the reader to decide which to include and which to exclude; it also provides an overview of the basic concepts of object-oriented design.The production of software in an increasingly competitive environment is making reuse a priority of software professionals. The popularity of the object-oriented technique is due, in part, to its support for reuse. Two important factors influence reuse: First, it is necessary to have a set of high-quality components that are worth reusing. Second, the components must be well-defined, easy to integrate, and efficient. Meyer's article presents some experiences in developing the classes for the Eiffel library; it also discusses characteristics of the library. For components to be reused, the designer must have the means to locate a component which models an entity in the current problem. Not only must the component be located, but often necessary supporting pieces must be found as well. The article by Gibbs et al. provides information on the management of classes and the software components of the object-oriented paradigm.Tom DeMarco, in a recent interview,2 declared parallel computing to be the emerging new paradigm. According to DeMarco object-oriented techniques will be an integral partner in this emergence. DeMarco observed that designing with objects preserves the natural parallelism in a problem. Agha addresses models for parallel objects, presenting an overview of the problem and focusing on the actor model as a possible solution. He presents examples of design issues when using the actor model. He also considers a basic reflective design architecture.The importance of well-defined and well-managed abstractions in the software development process is discussed in the articles by Meyer and by Gibbs et al as they explore what has come to be called the software base, the set of software components from which future products will be built.The unique components developed by object-oriented methods are characterized by an interface that is separate from the implementation of that behavior. The designer is free to concentrate on modeling the problem at hand either by developing specific classes or by locating and reusing existing classes that model some subset of the needed behavior. Meyer focuses on what he quotes McIlroy as terming a “software components subindustry,”3 presenting a case study of the development of the Eiffel libraries.The final article in this special issue, by Henderson-Sellers and Edwards discusses modifications to the traditional life cycle supported by the object-oriented approach. The modified life cycle recognizes the iterative nature of the development process and incorporates that characteristic into its model.Wirfs-Brock and Johnson present a sampling of current research into several aspects of object-oriented design. Their survey includes efforts to improve reusability through design technique and paradigm-specific tools. The works are representative of the broad spectrum of research activity currently under way.We would like to thank the authors in this special issue for their hours of work both in developing their own articles and for the time spent evaluating and commenting upon the other articles.

Abstract: Computer integrated design systems will require an improved understanding of the engineering design process, including formalized notions of (1) the structure of the process, (2) the design tasks that need to be performed, and (3) the information required to carry out these tasks. To help formalize the design process, certain conceptual tools are needed, including an organizational model for the process. This paper outlines such a model for structural engineering design, termed theMultilevel Selection-Development model, which is based on a decomposition of design problems intoselection anddevelopment subproblems. A few basic concepts involved in the engineering design process are reviewed, and the proposed model is outlined. The application of the model to a simple example is presented, and management of the interactions between subproblems is discussed.

Abstract: Much decision making in the real world takes place in an environment in which the goals, constraints, and consequences of possible actions are not known precisely. The tools of fuzzy set theory can be used to deal with such imprecision in a quantitative manner. This use and effectiveness of fuzzy theories in the formulation and solution of design problems are developed and described herein through application to two types of helicopter design problems involving multiple objectives. The first problem deals with the determination of optimum flight parameters to accomplish a specified mission in the presence of three competing objectives. The second problem addresses the optimum design of the main rotor of a helicopter involving eight objective functions. The tools of fuzzy set theory have been used to model the vague and imprecise information in the formulation of these problems. A method for solving the resulting fuzzy multiobjective problem using nonlinear programming techniques is presented. Results obtained using fuzzy formulation are compared with those obtained using crisp optimization techniques. The outlined procedure should be useful in engineering design situations in which uncertainty arises about the preciseness of permissible parameters, degree of credibility, and correctness of statements and judgments.

Abstract: A model of program design is proposed to explain program variability, and is experimentally supported. Variability is shown to be the result of different decisions made by programmers during three stages in the design process. In the first stage, a solution is created based on a particular design approach. In the second stage, actions in the solution are organized by features they share. The actions may then be merged together to define a more concise solution in program code, the third stage of design. Different programs will be created depending, on the approach taken to design the features selected to group actions in a solution, and the features used to merge actions to form program code. Each of the variants observed in the study was traced to the use of a specific piece of information by a programmer at one of the three stages of program design. Many different programs were created as the process of design interacted with the knowledge of the programmer.

Abstract: Part 1 Introduction: the computer human factors database, K.E.Phillips computer aided ergonomics - a tool for occupational safety and health, A. Genaidy, W. Karwowski and S.H.Mousavinezhad. Part 2 Anthropometry and computer models of man: SAMMIE - a man and workplace modeling systems, K.Case, J.M.Porter and M.C.Bonney WERNER - a personal computer implementation of an extensive anthropometric workplace design tool, W.B.Kloke. Part 3 Workspace design: ERGOSPEC - a prototype expert system for work station design, L.Brennan, L.Farrel and D.McGlennon CAD - Video - Somatography - a method for the anthropometric design of workplaces, H.J.Bullinger and D.Lorenz. Part 4 Workload and work measurement: job analysis and work design using ergonomic databases, K.Landau, et al OWLKNEST - a knowledge based expert system for selecting operator workload techniques, S.G.Hill and R.M.Harris. Part 5 Posture and manual handling of loads: computer aided posture analysis of the trunk, neck, shoulders and lower extremities, W.Monroe Keyserling OWASCA - a computer aided visualizing and training software for work posture analysis, S.Vayrynen, et al. Part 6 Artificial intelligence and safety analysis: strategy for developing an expert system for safety, K.Kjos knowledge based safety analysis in CAD enviroment, J.Suokas, P.Keino and I.Karvonen. Part 7 User - machine interface: INTUIT - intelligence user interface design tool, A.J.Russell computer aided design applied to the flight telerobotic service user interface, M.A.Stuart and R.L.Smith. Part 8 Performance evaluation and decision support: SPES - assessing the effects of the work on a man with compuerized performance testing, F.Gamberale, A.Iregren and A.Kjellberg. Part 9 CAD - Ergonomic design process: the contribution of CAD to the enhancement of the ergonomists' role in the design process, L.Brennan and E.F.Fallon.

Abstract: The design of most engineering systems is a complex and time-consuming process. In addition, the need to optimize such systems where multidisciplinary analysis and design procedures are required can cost additional human and computational resources if proper software and numerical algorithms are not used. Several computational aspects of optimization algorithms and the associated software must be considered while making comparative studies and selecting a suitable algorithm for practical applications. Several parameters, such asaccuracy, generality, robustness, efficiency and ease of use, must be considered while deciding the superiority of an optimization approach. Approximate algorithms without sound mathematical basis can be sometimes more efficient for a specific problem, but fail to satisfy other requirements. They are, therefore, not suitable for general applications. An objective of the paper is to emphasize the critical importance of the above-mentioned parameters in large scalestructural optimization and other applications. Theoretical foundations of two promising approaches, thesequential quadratic programming (SQP) andoptimality criteria (OC), are presented and analysed. Recent numerical experiments and experiences with the SQP algorithm satisfying these requirements are described by solving a variety of structural design problems. An important conclusion of the paper is that the SQP method with a potential constraint strategy is a better choice as compared to the currently prevalent mathematical programming (MP) and OC approaches.