Tasks, hierarchies, and flexibility Planning in Food Processing Industries Wout van Wezel
Uitgever: Labyrint Publication Postbus 662 2900 AR Capelle a/d IJssel Nederland Drukwerk: ISBN 90-72591-98-4 2001, W.M.C. van Wezel Alle rechten voorbehouden. Niets uit deze uitgave mag worden verveelvoudigd, opgeslagen in een geautomatiseerd gegevensbestand, of openbaar gemaakt, in enige vorm of op eniger wijze, hetzij elektronisch, mechanisch, door fotokopieën, opnamen, of enig andere manier, zonder voorafgaande schriftelijke toestemming van de auteur. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system of any nature, or transmitted in any form or by any means, electronic, mechanical, now known or hereafter invented, including photocopying or recording, without prior written permission of the copyright-owner.
RIJKSUNIVERSITEIT GRONINGEN Tasks, hierarchies, and flexibility Planning in Food Processing Industries Proefschrift ter verkrijging van het doctoraat in de Bedrijfskunde aan de Rijksuniversiteit Groningen op gezag van de Rector Magnificus, dr. D.F.J. Bosscher, in het openbaar te verdedigen op donderdag 22 november 2001 om 16.00 uur door Wouter Maria Coenraad van Wezel geboren op 5 februari 1970 te Nijmegen
Promotores: Referent: Beoordelingscommissie: Prof. Dr. Ir. G.J.C. Gaalman Prof. Dr. R.J. Jorna Dr. D.P. van Donk Prof. Dr. A.M. Meystel Prof. Dr. B.J. Wielinga Prof. Dr. J. Wijngaard ISBN 90-72591-98-4
Table of Contents Acknowledgements...vii Preface...ix Chapter 1. Introduction...1 1.1. Market characteristics of the Food Processing Industries...1 1.2. Planning in the Food Processing Industries...4 1.3. Research outline...8 Chapter 2. Food Processing Industries...11 2.1. Introduction...11 2.2. Introductory case 1: a chocolate factory...12 2.3. Introductory case 2: a cookie factory...14 2.4. Market characteristics: supply chain and competition...17 2.5. Organizational characteristics...19 2.6. Production system characteristics...21 2.7. Analysis of conflict...30 2.8. Conclusion...33 Chapter 3. Planning and Planning Support...35 3.1. Introduction...35 3.2. The role of human planners...35 3.3. The entities in the plan...50 3.4. Computerized planning support...53 3.5. Schedule generation...58 3.6. Conclusion...64 Chapter 4. Models of planning...67 4.1. Introduction...67 4.2. Variety in the application domain and reuse of models...67 4.3. The Scheduling Expertise Concept...73 4.4. Conclusion...89 Chapter 5. Planning concept for the Food Processing Industries...91 5.1. Introduction...91 5.2. Models of planning in Food Processing Industries...92 5.3. Reflection on the analysis of conflict...103 5.4. Analysis of flexibility...104 5.5. The task strategy for continuous planning...117 5.6. Planning support requirements for continuous planning...120 v
5.7. Conclusion...121 Chapter 6. System architecture and planning support prototype...123 6.1. Introduction...123 6.2. Reuse requirements...123 6.3. System architecture...124 6.4. Case illustration...131 6.5. Conclusions...141 Chapter 7. Conclusions and generalizations...143 7.1. Introduction...143 7.2. Research conclusions...143 7.3. Generalization of the research results...148 7.4. Directions for further research...152 References...155 Summary...163 Samenvatting (Dutch)...167 vi
Acknowledgements There is no other way to start this thesis than by thanking Mariette. The first reason for this is that she can stop reading now if she wishes. There is probably nothing more boring than 150 pages working notes of a spouse. The second reason is that she always motivates me to do the things I like, and thereby even condones my habits. Although she likes to go to the zoo all the time and for the rest of the time read books in a somewhat organized household, I only want to work on the computer surrounded by a total mess. Although this sounds opposing, I think it is complementary, and my feelings of love provide the indisputable evidence. At this point, I also need to mention Froukje. She has tried as hard as a baby can to stay quiet and let me work while she was in one of her major distresses, such as hunger, a wet diaper, and feeling generally bored, or when she was facing her first big questions of life, such as why can t I crawl to that indistinguishable but nonetheless much nicer spot on the carpet and where is Fiefel. Mariette and Froukje, thanks for everything! Although a lot of people have contributed to my research, I need to mention three in particular. Gerard Gaalman not only lets me work on the subjects that I like, but he also allows me to do it in a way that fits me. Our discussions and his wide interests greatly stimulate me. René Jorna has been my mentor since the start of my graduation project. He always motivates me with his seemingly uninterruptible source of energy. Dirk Pieter van Donk has taught me to sit back and watch from a distance once in while. He always knows how to put things in perspective when all I see is swirling spaghetti. The three of them have shared their views and knowledge with me and they have allowed me to make use of this in my own way. For that, I am grateful. Prof. Dr. A.M. Meystel, Prof. Dr. J. Wijngaard, and Prof. Dr. B.J. Wielinga have thoroughly read the thesis. I would like to thank them for their time and comments. I also thank the planners and production managers that have allowed me to bother them with questions in the past eight years. The insights they have provided me with have been indispensable for my research. As said, many (former) colleagues have contributed to my research, and I take this opportunity to acknowledge some of them that have had much influence on my career choices (in chronological order): Ap Rutges, Henk Gazendam, Constantijn Heesen, Tomas Klos, Simon Sibum, and Erik Huisman. My family and friends are very important to me. I am very thankful for the everlasting encouragements of my mother and father to pursue my (wide) interests, and for their relentless operational support in all my activities. The fact that my father is not here anymore to read my work is one of my great sorrows. It is hard to explain that his passing caused a gap in my motivation but at the same time stimulated me to proceed. I very much hope he would have been proud of me. Groningen, October 9 th 2001. vii
Preface The initial impetus for this research was to apply the Scheduling Expertise Concept in the domain of production planning. Or, as we say it in our faculty, it was one of the projects that attempt to assimilate some of the research of the 8 th floor (the production people; my current habitat) and the 9 th floor (the computer people; my place of origin). More specifically, the aim in this study was to apply a task oriented planning and scheduling support approach in the food processing industries. Personally, I have learned much from this exercise, and I hope that my colleagues have enjoyed the many discussions as much as I have. In light of the above, it is not surprising that the thesis deals with different perspectives on planning that each have their own research school: planning and production control, planning in psychology, and computerized planning support. Each of these areas has my profound interest. Still, due to the nature of the original goal of this research, the analyses of planning in the food processing industries that we made, do not have the elaboration and depth that can be expected from the distinct perspectives. A detailed cognitive task analysis is not provided, there is no in-depth quantitative analysis of the production system or of the scheduling characteristics, there is no elaborate empirical case study to test our hypotheses, and there is no fully working scheduling support system. The results of this research are twofold. First, there are theoretical contributions to each perspective. Second, we pay attention to integration of the approaches. Although the aforementioned single discipline in-depth analyses are challenging and interesting, even from a scientific research point of view, they are not really necessary to answer the research question. The answer can be given by combining concepts from the three disciplines: tasks, hierarchies, and flexibility. Accidentally, we thereby also reach our secondary goal. Planning support by using domain knowledge (the 8 th floor) and planning support by doing task analyses (the 9 th floor) are approaches that can be fruitful on their own, but a combination can both reduce development efforts and increase the quality of the outcome. ix