CADOM: A Component Agent-based Design-Oriented Model for Collaborative Design

Information technology is the foundation for collaborative design. This paper reviews the state-of-the-art of the current research on product modeling, and a schema for a Design-Oriented Model (DOM) containing functional, structural and management data is proposed. The functional data explains the design purpose, function, object behavior and design rationale; the management data is for keeping the consistency of the model data, capturing the evolution process and controlling the operation action and authority; the structural data is the core of the model data. The integration of functional and management data directs the model towards design integration in place of application integration. The modeling system adopts the Component Agent (CA) mechanism that represents a complex product in an intelligent, autonomous hierarchy. A CA encapsulates the DOM data and consists of a definer, a communicator, an adaptor and a manager. These units are responsible for defining the model data, interacting with other agents, deriving special data and managing the constraints, version, authority and operation. Finally, several aspect supporting the collaborative design enabled by the CADOM (CA-based DOM) are discussed, as the multi-views model, the semantics communication between perspectives, the dynamic constraints management, the version and authority management, and the product and process integration. The discussion indicate that the model is an information infrastructure with more capabilities for collaborative design.     

Framework for Modeling Dependencies in Collaborative Engineering Processes

This article describes an engineering process representation and modeling tool. The approach is especially suitable for describing large-scale, mature design processes involving numerous tasks, some of which may be performed by automated computer agents. The underlying representation is a graph of information-processing units with explicitly defined input and output feature elements. We show that this representation is more complete than those used in previous process modeling approaches and overcomes some of their limitations when dealing with design processes involving dependencies at multiple levels of detail. The representation is combined with rules for automatically operating upon the graph to preserve consistency when traversing to higher or lower levels of detail.     

Coordination Approaches and Systems – Part I: A Strategic Perspective

This is the first part of a two-part paper presenting a fundamental review and summary of research of design coordination and cooperation technologies. The theme of this review is aimed at the research conducted within the decision management aspect of design coordination. The focus is therefore on the strategies involved in making decisions and how these strategies are used to satisfy design requirements. The paper reviews research within collaborative and coordinated design, project and workflow management, and, task and organization models. The research reviewed has attempted to identify fundamental coordination mechanisms from different domains, however it is concluded that domain independent mechanisms need to be augmented with domain specific mechanisms to facilitate coordination. Part II is a review of design coordination from an operational perspective.     

A Subjective Design Framework for Conceptual Design of Polymeric Processes with Multiple Parameters

Polymer processes are in general difficult to model, especially because of coupling between process conditions, polymeric behaviors and geometries. Arising from high thermal gradients, non-Newtonian viscous behaviors and non-linear pressure effects, polymer processing is not well described mathematically. A conceptual design methodology is proposed formally as a useful tool for treating polymeric processes with multiple performance parameters on a structured design platform. Without resorting to engineering models, this approach deals with the initial selection of process conditions within a three-stage framework: (1) qualitative design; (2) process modeling; and (3) quantitative design. Based on subjective reasoning, this procedure makes it possible to account for one’s prior experience, and incorporate it into the process development. The notion of conceptual robutstness is introduced to ensure deesign quality in the early-stage process development. A case study of compression molding is illustrated in a step-by-step manner.     

A Taxonomy for Design Requirements from Corporate Customers

We have developed a taxonomy that classifies those needs of a corporation that impact product design. We call these needs corporate requirements. In contrast to the consumer or end-user requirements, corporate requirements come from internal sources such as marketing, finance, manufacturing, and service. This taxonomy allows for an organized method of gathering, managing, and retrieving the requirements. The taxonomy also helps to facilitate a broader, clearer form of Quality Function Deployment. Generic in nature, this taxonomy provides a template with which to create taxonomies for a given product within a given company or industry. We include an industrial case study to demonstrate this concept.     

Building Agility for Developing Agile Design Information Systems

Agile manufacturing relies heavily on the quality of information that organizations have and on their ability to organize and reuse it. Constant inflow of information and knowledge is the fuel of agile manufacturing. In the process of forming virtual enterprises, these new organizations have to be equipped with information systems that integrate their present legacy technology and improve upon it. To support the quick formation of virtual organizations, one must have the ability to develop such systems quickly. Over the past few years we have evolved, through collaborative projects with industry, an approach composed of methods and an information infrastructure called n-dim that improves the ability of becoming agile manufacturers of information systems, by responding quickly to information needs of new and evolving organizations. Following an analysis of the requirements of information systems for agile design, we discuss this approach; describe some of the infrastructure features; and present several examples of simple applications that illustrate them. We summarize by discussing the advantages and limitations of our approach.     

Performing Changes in Product Development: A Framework with Keys for Industrial Application

Industrial product development requires continuous improvements in work procedures as a result of constantly changing demands. Support tools have proven to be an oft chosen way to meet new demands; however, few research efforts have been made in how to implement new tools. This article is a contribution to knowledge on carrying out the implementation of support tools. The basis consists of four field studies performed during 1994–1999, containing 78 qualitative research interviews and focusing on the implementation and use of different support tools. A re-analysis has been performed of selected interviews from the field studies, in total 30 interviews. This resulted in recommendations for an implementation framework, consisting of an Implementation Cycle, Organizational Change Field and Managerial Consistence, and five implementation keys: Goal setting, Kowledge Development, Anchoring at All Levels, Suitable Resources and Focus on the Individual.     

A Theory of Complexity, Periodicity and the Design Axioms

One of the topics that has received the attention of mathematicians, scientists and engineers is the notion of complexity. The subject is still being debated, as it lacks a common definition of complexity, concrete theories that can predict complex phenomena, and the mathematical tools that can deal with problems involving complexity. In axiomatic design, complexity is defined only when specific functional requirements or the exact nature of the query are defined. Complexity is defined as a measure of uncertainty in achieving a set of specific functions or functional requirements. Complexity is related to information, which is defined in terms of the probability of success of achieving the Functional Requirements (FRs). There are two classes of complexity: time-dependent complexity and time-independent complexity. There are two orthogonal components of time-independent complexity, i.e., real complexity and imaginary complexity. The vector sum is called absolute complexity. Real complexity of coupled design is larger than that of uncoupled or decoupled designs. Imaginary complexity can be reduced when the design matrix is known. As an example of time-independent imaginary complexity, the design of a printing machine based on xerography is discussed. There are two kinds of time-dependent real complexity: time-dependent combinatorial complexity and time-dependent periodic complexity. Using a robot-scheduling problem as an example, it is shown that a coupled design with a combinatorial complexity can be reduced to a decoupled design with periodic complexity. The introduction of periodicity simplifies the design by making it deterministic, which requires much less information. Whenever a combinatorial complexity is converted to a periodic complexity, complexity and uncertainty is reduced and design simplified.     

A-Design: An Agent-Based Approach to Conceptual Design in a Dynamic Environment

This paper provides an introduction to a new design methodology known as A-Design, which combines aspects of multi-objective optimization, multi-agent systems, and automated design synthesis. The A-Design theory is founded on the notion that engineering design occurs in interaction with an ever-changing environment, and therefore computer tools developed to aid in the design process should be adaptive to these changes. In this paper, A-Design is introduced along with some simple test problems to demonstrate the capabilities of different aspects of the theory. The theory of A-Design is then shown as the basis for a design tool that adaptively creates electro-mechanical configuration designs for changing user preferences.     

Tuning Parameter Tolerance Design: Foundations, Methods, and Measures

In this paper, a novel technique is presented to solve tolerance design problems. To achieve the desired performance tolerance, the technique uses a subtle, but significant, change in the design: the addition of a tuning parameter in place of an increase in component precision. Statistical models are used to develop a framework for the tuning parameter design method. Also developed is a new, dimensionless design metric which ranks candidate tuning parameters. A step-by-step method is developed for the application of tuning parameters using this metric. The step-by-step tuning parameter design method is applied to a heavy-duty manual stapler as a clarifying example.     

Design Support Using Distributed Web-Based AI Tools

Currently, designers are faced with searching through a ‘sea’ of on-line knowledge to support their decision making activities. This paper describes WebCADET, which is a reimplementation of the stand-alone CADET – a Knowledge-Based System (KBS) for product design evaluation. WebCADET aims to provide effective and efficient support for designers during their searches for design knowledge. WebCADET uses the ‘AI as text’ approach, where KBSs can be seen as a medium to facilitate the communication of design knowledge between designers. The development of WebCADET to include practical support via World Wide Web-based functionality, which illustrates the potential of the ‘AI as text’ approach, is described in the paper.     

Structure and Matrix Models for Tolerance Analysis from Configuration to Detail Design

A substantial amount of all quality problems that arise during assembly can be referred back to the geometrical design, and especially the geometrical concept of the product, i.e. the way in which parts are designed and located with each other. Special emphasis should thus be put on geometry design, especially during the early design phases, to try to find robust concepts and avoid solutions that may cause down-stream production problems.  This paper presents a generic set of evaluation tools for robust geometry design encountering (i) potential tolerance chain detection in configuration design, (ii) assembly robustness evaluation in concept design, and (iii) tolerance sensitivity analysis in detail design. Special attention is given to the development of a new matrix-based evaluation tool for the configuration design part. The tool presented is based on a new way of representing geometry variation constraints in an enhanced function-means tree structure model. Different parts of the function-means tree that are of interest for analysis purposes are then extracted and converted to matrix representation. The reason for doing this is that the structure model is most suitable for modeling, but becomes unsuitable for analysis as the model complexity increases. For this latter purpose, the matrix representation is far better. The use of the different tools is demonstrated in the design of a new vehicle front system for which the geometry a priori is unknown.     

Internet-Based Design Catalogue for the Shaft and Bearing

The Internet and World Wide Web (WWW) are evolving as an important communication technology. This paper examines the development of an Internet-based online catalogue on the WWW. An interactive website is prepared that helps a remote designer to design shafts and bearings based on various input parameters provided. The web site also provides solid models of the shaft to perform CAD and FEM analysis. This permits the user to make further investigations, and helps to modify the design satisfactory.     

‘Signposting’, A Parameter-driven Task-based Model of the Design Process

This paper addresses the need for computer support in aerospace design. A review of current design methodologies and computer support tools is presented, and the need for further support is discussed, with particular reference to the early formative stages of the design process. A parameter-based model of design is proposed, founded on the assumption that a design process can be constructed from a predefined set of tasks. This is supported by knowledge of possible tasks in which the confidence in key design parameters is used as a basis for identifying, or signposting, the next task. A prototype implementation of the signposting model, for use in the design of helicopter rotor blades, is described and results from trials of the tool are presented. Further areas of research are discussed.     

External Support of Problem Analysis in Design Problem Solving

Design is described as creative design problem solving. The first step of the design process is to identify and analyze the design problem. This step has an important influence on the creation of an effective design solution. In two experiments, we tested the benefits that sketching provides during the analysis process in design problem solving. In particular, this paper focuses on the design process, the act of sketching, the sketch itself, and the final product. In prior studies, the process of sketching has been shown to enhance the construction of a mental representation, and thus the sketch has improved the analysis of the problem. The memory supporting effect of sketches is verified in the second experiment discussed in this paper. Finally, this paper also discusses the support possibilities the sketch offers for the early stages of the design process.     

A Study on Engineering History Base

During engineering processes, many kinds and amounts of information are used and produced. Such information is useful in successive cases, and thus its reuse is desired. In this paper, information on attributes of the products is referred to as ‘product information’, and information on the reasons for and/or history of a designer’s thought process is referred to as ‘process information’. According to this classification, process information can be used for obtaining an explanation of product information. The purpose of this work is to build a database, called an ‘engineering history base’, from which engineers can retrieve explanations to enable the reuse of product information. In this paper, explanation from the ‘process’ viewpoint is thought to be important in promoting the reuse of product information. There are two types of explanation for the process: teleological and causal. However, until now, little attention has been paid to the causal explanation for the process. Thus, in this paper, an information model which focuses on both types of explanation is proposed. The model is adopted for the engineering history base and a prototype system is developed. The appropriateness of this model is discussed by analyzing the actual data in the development of a color video printer.     

A Dominance-based Design Metric in Multiattribute Robust Design

This paper outlines the development of an effective and consistent ‘designing-in-quality’ strategy that can be used to deal with concepts of uncertainty, quality and robustness in engineering design. Specifically, this paper presents a decision analysis-based robust design metric that seamlessly integrates objective evaluations on the goodness of a design alternative with the designer’s intent and preferences. This is achieved through the development of a set of performance-reflecting dominance indices for the attributes and their utilization in a preference-influenced multiattribute utility formulation. Such a knowledge feedback-based decision model development will be particularly useful when dealing with complex iteration-based engineering design process where little information on the expected outcomes may be known a priori, or where product performance is computationally expensive to evaluate. Application of this robust design metric in a multi-stage experimentation and modeling design process is presented. The characteristics of the proposed design metric and the effectiveness of the overall design procedure in dealing with constrained engineering design problems are examined with the aid of demonstrative case studies and the results are discussed.     

Arrow's Theorem and Engineering Design Decision Making

This article establishes that Arrow”s General Possibility Theorem has only indirect application to engineering design. Arrow”s Theorem states that there can be no consistent, equitable method for social choice. Many engineering design decisions are based on the aggregation of preferences. The foundation of many engineering decision methods is the explicit comparison of degrees of preference, a comparison that is not available in the social choice problem. This explicit comparison of preference levels is coupled with the choice of an aggregation method, and some forms of aggregation may be inadequate or inappropriate in engineering design.     

Strategic technology planning in hospital management

Abstract. Hospital managers regularly are confronted with their patients' demand for increased service performance on the one hand and tight budgets on the other. As medical technologies influence both the costs and the service spectrum, strategic technology planning is among the critical tasks in hospital management. This paper addresses the corresponding problem of selecting the “best” portfolio of medical devices and proposes an appropriate decision support system. It starts with a multiobjective mathematical programming model that determines the solution space of all efficient portfolios of medical technology investments. The members of the planning committee with their diverging interests then are supported by their interactive exploration of that space until they jointly reach a satisfying portfolio and are not willing to make any further compromises between its objective levels. As one of its salient features the system does not require a priori preference information. RID="*" ID="*" A previous version of this paper has been presented at the Wiesbaden 2000 Meeting of the GOR-Working Group “Operations Research in Health Care”. The authors thank Andrea Lührs and Thomas Rollins, both from Siemens AG, for their valuable support. Moreover, thanks are due to the anonymous referees for their comments on a previous version of this paper. Correspondence to: C. Stummer