Decision Engineering Springer London Berlin Heidelberg New York Hong Kong Milan Paris Tokyo Series Editor Dr.Rajkumar Roy Department ofEnterprise Integration School ofIndustrial and Manufacturing Science Cranfield University Cranfield Bedford MK43 0AL UK Other titles published in this series Multiobjective Optimisation Yann Collette and Patrick Siarry Using the Analytic Hierarchy Process Navneet Bhushan and Kanwal Rai Publication due October 2003 From Product Description to Cost Pierre Foussier Publication due September 2004 Jerzy Pokojski IPA – Concepts and Applications in Engineering 1 Springer Jerzy Pokojski,PhD Institute ofMachine Design Fundamentals,Warsaw University ofTechnology, Narbutta 84,02-524 Warsaw,Poland British Library Cataloguing in Publication Data Pokojski,Jerzy IPA:concepts and applications in engineering.– (Decision engineering) 1.Engineering design – Data processing 2.Decision support systems I.Title 620' .0042'0285 ISBN 1852337419 Library ofCongress Cataloging-in-Publication Data Pokojski,Jerzy. IPA—concepts and applications in engineering / Jerzy Pokojski. p.cm.— (Decision engineering) Includes index. ISBN 1-85233-741-9 (alk.paper) 1.Engineering design.2.Expert systems (Computer science).3.Multiple criteria decision making. I.Title.II.Series TA174.P635 2003 620'.0042—dc21 2003050550 Apart from any fair dealing for the purposes ofresearch or private study,or criticism or review,as per- mitted under the Copyright,Designs and Patents Act 1988,this publication may only be reproduced, stored or transmitted,in any form or by any means,with the prior permission in writing ofthe publish- ers,or in the case ofreprographic reproduction in accordance with the terms oflicences issued by the Copyright Licensing Agency.Enquiries concerning reproduction outside those terms should be sent to the publishers. ISSN 1619-5736 ISBN 1-85233-741-9 Springer-Verlag London Berlin Heidelberg a member ofBertelsmannSpringer Science+Business Media GmbH http://www.springer.co.uk © Springer-Verlag London Limited 2004 CLIPS is a rule-based language that was developed by NASA’s Johnson Space Center. GBB is the product ofKnowledge Technologies,International Inc.,Flexible Service Center,211 West State Street,Suite 203,Media,PA 19063,USA.http://www.ktiworld.com/GBB/ Goldworks III is the product of GoldHill, 36 Arlington Road, Chestnut Hill, MA 02467, USA. http://www.goldhill-inc.com/goldworks.htm The use ofregistered names,trademarks,etc.in this publication does not imply,even in the absence of a specific statement,that such names are exempt from the relevant laws and regulations and therefore free for general use. The publisher makes no representation,express or implied,with regard to the accuracy ofthe informa- tion contained in this book and cannot accept any legal responsibility or liability for any errors or omis- sions that may be made. Typeset by Gray Publishing,Tunbridge Wells,Kent,UK Printed and bound by in the United States ofAmerica 69/3830-543210 Printed on acid-free paper SPIN 10876500 Preface This book presents the results ofextensive research in computer-supported decision processes in engineering,carried out over many years by the author and his collab- orators.The author has cooperated with designers in Poland and in Germany.Very often there was university–industry cooperation for the building of specific soft- ware for certain engineering tasks. The majority ofthe concepts,for example “the designer’s personal assistant”and the decomposition and coordination of multicriteria decision problems, evolved through cooperation with designers in this field.The author,while working together with them,understood that this group ofpeople is characterised by a strong indi- vidualism and that the range ofapplied approaches and methods is wide. The most significant influences on the author’s opinions through contact with the designers were the lectures he delivered for more than 12 years for post-graduate studies on computer-aided design in machinery. The lectures included seminars which required the creation ofconcepts for an individual computer support system for decision processes,generally well known to the designers who participated in the lectures. In the theoretical part the characteristics of the actual computer-aided design and engineering (CAD and CAE) tools were depicted,whereas in the practical part the students created concepts ofcomputer environments for the realisation of design projects in their own professional work.The task was confined to the expres- sion ofthe design process.This was followed by the development ofa concept for the implementation of different computer technologies in the next stages of their processes.The lectures were attended annually by 15 to 25 participants,allowing the teacher the opportunity to cover quite a wide spectrum of real industrial design processes.The majority ofstudents worked in machine industries with different pro- duction outputs and product ranges:from aircraft components to a production line for the spraying ofcar bodies,and from the development ofmobile aerial systems to the production oflightbulbs.Several concepts worked out during the seminars were later realised in practice. It remains to be added that the lectures were conducted flexibly and openly and did not aim at systematic design according to a certain design theory.Although elem- ents ofdifferent schools were taught,it was left entirely to the students to choose. Many ofthe problems that were subjects ofthe lectures were later picked up and further developed by ordinary students and research students.Looking at the multi- tude of solutions of the design processes,the author drew the conclusion that the designers’individualism and internal personal factors play an essential role.Because ofthat it became important to notice the permanent development ofindividual engin- eering knowledge,its richness in facets and its constant evolution.Another obser- vation is the omnipresent re-using ofprevious processes,their forms ofdescription and the adjustment of the modelling.In spite of certain limitations,often creative v vi Preface elements with the freedom to create new processes could be observed.This mostly worked by using well-known tools,that is,existing and reliable sub-processes. Interesting was the relationship between designing and the multicriteria optimi- sation methods.It became obvious that the multicriteria optimisation methods pre- sented as decision-making theory were widely accepted in connection with everyday decision problems. All of this brought forth a palette of applications based on production realities, which existed at least as prototypes.Some found application in real life,some were implemented within larger projects,and others became the beginnings ofa product that is still being developed. Apart from the direct working collaboration there were many discussions,com- ments and suggestions. A good deal ofthe work that formed the backbone ofthis book was realised by my research students Pior Cichocki and Maciej Gil. Various problems concerning the computer tools were solved by my colleagues and collaborators of the computer techniques team at the Institute of Machine Design Fundamentals at the Warsaw University ofTechnology:Janusz Bonarowski, Jacek Jusis, Boguslaw Kozicki, Grzegorz Linkiewicz,Witold Marowski, Stanislaw Skotnicki,and Jerzy Wróbel. Many problems were solved practically by numerous students,research students and participants ofthe post-graduate studies. I would like to thank everyone mentioned above for taking part in the research. Also many thanks to my “English advisers”, my wife Antonia and our friends Sophie and Chris Klimiuk who made every endeavour to give my book its final shape. Contents 1. Introduction to the Problems ofKnowledge-based Engineering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 The Role ofKnowledge in Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Concepts ofDesign Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1.2.1 Design Knowledge Repositories . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1.2.2 Introduction to the Concept ofan Intelligent Personal Assistant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 1.3 Examples Explaining the Sense ofKnowledge in Engineering Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2. The Nature ofthe Personal and the Team-based Design Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3. Survey ofEngineering Knowledge Representations . . . . . . . . . . 39 4. Survey ofIntelligent Personal Assistant Software Concepts . . . 51 5. A Common Model ofan Intelligent Personal Assistant Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 6. Intelligent Personal Assistant – Concepts for Solving Integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 7. Intelligent Personal Assistant – Design Process Modelling . . . . 81 8. Intelligent Personal Assistant – Knowledge Modelling . . . . . . . . 99 9. Intelligent Personal Assistant – Optimisation . . . . . . . . . . . . . . . . 113 9.1 Multiobjective Optimisation Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 9.2 Formal Model ofa Machine Design Problem . . . . . . . . . . . . . . . . . . . . . 118 9.3 Two-level Optimisation Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 9.4 Concepts ofCriteria Space Ordering . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126 9.5 Relationships Between Different Concepts ofCriteria Space Ordering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 9.6 A Survey ofSelected Multiobjective Optimisation Methods . . . . . . . . 129 vii viii Contents 9.6.1 Methods Based on the Value Function Concept . . . . . . . . . . . . . . 129 9.6.2 Method ofInteractive Multiobjective Optimisation . . . . . . . . . . 130 9.6.3 Method ofConstraints and Utopia Solution . . . . . . . . . . . . . . . . 131 9.6.4 Lexicographic Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 9.6.5 Characteristics ofMultiobjective Optimisation Methods . . . . . 133 9.7 Additional Assumptions in the Formulation ofLarge Optimisation Problems in Machine Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 9.8 Method ofLeading and Related Sub-problems . . . . . . . . . . . . . . . . . . . 137 10. Intelligent Personal Assistant – Implementation . . . . . . . . . . . . . 145 11. Intelligent Personal Assistant – Unified Framework . . . . . . . . . . 157 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 1 Introduction to the Problems of Knowledge-based Engineering 1.1 The Role of Knowledge in Design This book is concerned with mechanical engineering.Most ofthe considerations, comments and examples presented in the following chapters deal with mechanical products and mechanical design processes. The goal of design is to create a vision of a product.The product is then mar- keted with the aim ofachieving a scheduled position.The design procedure is car- ried out by designers working individually or in design teams.They have to start the whole procedure from an initial specification.First they plan their design activ- ities and discuss details of the design. The designers’ planning and handling is based on short-/long-distance strategies.The strategies can have many different goals.Designers have to develop the concepts of a product,which are then evalu- ated,and subsequently the designers generate a project in detail.The detailed doc- umentation is nowadays mostly done by computer. Design is an activity where designers create new solutions.This activity,since it has a beginning,a middle consisting ofvarious stages,and an end,is called a process (Figure 1.1).It is very difficult to create a formal model ofsuch an activity.Not every step has a formal representation.Much ofthe activity can take place in the designer’s mind and so not necessarily be apparent to others.The designer,looking for new solutions,tries to test his ideas.He has to model real situations.He decides what is modelled and how.He analyses,considers different aspects,evaluates and synthe- sises.The whole process consists of a number of actions which are treated by the designer as important, such as which should be performed. The results of these actions support the process ofdecision making – selecting partial solutions,select- ing subsequent problems and steps.Finally,the designer decides when the results are satisfactory and discontinues all actions. Let us take an example:the design process of the braking system design for a mobile crane. Example 1.1 The process is based on real industrial procedures [12].The process, proposed and used by an industrial office,was routine but it was the product of longstanding design experience. The procedure was developed some years ago when calculations were generally carried 1 2 IPA – Concepts and Applications in Engineering time Product representations ... Process representation Process activities Figure 1.1 Product and process representations. out without the use of computers.It consists of linearly placed steps that are followed sequentially (Figure 1.2).In the case of difficulties with fulfilling constraints in one of the steps it was necessary to repeat the design process from one of the steps preceding the cor- rected step.Consequently the whole procedure had a linear form. The original version of the process was depicted as a scheme on paper and was stored in that form.The scheme includes places where the designer had to look for external sources of information:catalogues, standards,etc.Every step was regarded as an important activity,and as such was connected with a number of design variables for which values had to be obtained during that step.The values of the design variables were calculated or selected from standards or catalogues. Design processes can be classified as routine,innovative or creative [10,12,32, 109] (Figure 1.3).The borders between these classes are not very rigid.However, our example can be called a routine process.