282 Book Reviews

G.W. EVANS, W. KARWOWSKI and M.R. W ILHELM (eds.)

Applications of Fuzzy Set Methodologies in In- dustrial Engineering

Elsevier, Amsterdam, 1989, ix + 335 pages, Volume 8 in the series of Advances in Industrial Engineering, with G. Salvendy as series editor

The foreword by Hans Zimmermann and the preface by Gerald Evans clearly outline the pur- pose of the book: many problems in industrial design and development are human-centered, that is, dependent on human judgement, and fuzzy-set approaches seem to be very appropriate when the modelling of human judgement is necessary. Thus, the editors set out to subdivide the field of in- dustrial engineering into a number of sub-disci- plines (control of industrial processes, traditional industrial engineering, human factors, organiza- tional design and financial management, oper- ations research and decision making, and miscella- neous applications), whereafter they sought vari- ous contributions from researchers who are cur- rently involved in the application of fuzzy-set methodologies. The result is a collection of 24 papers, 13 from the USA, and 1 or 2 papers written by authors from each of the following countries: Austria, Canada, China, Czechoslo- vakia, Finland, France, Japan, Poland, and the Soviet Union.

The first contribution is an introductory survey paper by the editors. They briefly summarize the basic concepts in fuzzy-set theory, but in principle the book is intended for readers who are familiar with the basics and with industrial engineering.

Of course, the average length of the contribu- tions (14 pages) does not allow the reader to expect a thorough description of the applications, with all the technical and computational details. The book can just give an idea of the areas where fuzzy-set theory has been accepted or where it may penetrate. It is wor th keeping in mind that several authors do not really describe full-fledged applications. What they present, is a sketch of applicable methodologies and workable support- ing software. Whether these techniques have the potential to be accepted by industrial engineers is questionable, and the proof is still to be given.

We have two critical comments. First, although the basics of fuzzy-set theory are supposed to be

known to the reader, several authors still find it necessary to explain, for instance, the concept of a fuzzy number and the operations on fuzzy num- bers as proposed by Dubois and Prade. Obviously, a more elaborate introduction in the field and some more rigorous editing would have been ben- eficial for the book. Second, and this is a more serious comment, most papers just formulate a fuzzy model as if there would not be an alterna- tive, perhaps probabilistic model to satisfy the needs of the user. Moreover, which phenomenon has been modelled by these fuzzy concepts and fuzzy relationships? Human vagueness presuma- bly, but it is not so easy to explain why this vagueness is properly modelled via the tools and techniques of fuzzy-set theory, and the contribu- tors do not really clarify the point. Do the oper- ations on fuzzy numbers properly reflect vague, human reasoning? And what is the value of a model which follows human vagueness instead of a crisp, normative logic?

Nevertheless, we recommend the book to those who are interested in the potential of fuzzy logic. Human vagueness is everywhere present in design and development. Any tool to model and to analyze vagueness must be most welcome, not only in industrial engineering, but also in business administration and in political decision making.

Freek A. LOOTSMA Delft University of Technology

Faculty of Mathematics and Informatics P.O. Box 356, 2600 AJ Delft

The Netherlands

A. CHIKAN

Progress in Inventory Research. A Selection of Papers Presented at the Fourth International Sym- posium on Inventories, Budapest, August 25-29, 1986

Elsevier, Amsterdam, 1989, xii + 446 pages, US$155.25/Dfl.295.00

A selection of papers presented at the Fourth International Symposium on Inventories held in Budapest, Hungary, on August 25-29, 1986, is contained in this volume. Biannually many re- searchers from the field of inventory research from all over the world attend this symposium organised

Book Reviews 283

by the International Society of Inventory Re- search and present papers of high quality within three sections:

(i) Inventories in the national economy. (ii) Inventory management.

(iii) Mathematical modelling of inventories. About 70 papers of authors from 21 countries are collected in the three sections. Macroeconomic inventory problems related to credit policy, inter- firm competition, stocks and flows, business cycles, market and planned economies, fluctuation, dis- equilibrium etc. are discussed in the first section by scholars from east, west and the third world. Most of the papers use macro/micromodel l ing to study real life problems and provide interesting data. The papers "The impact of credit policy on macro inventory behavior in the hungarian econ- omy" by Abel and Szalkai (Hungary, USA), "A note on the valuation and verification of invento- ries" by Ghosh (India) and "The main tendencies of inventory movement in the USSR's national economy and measures undertaken to accelerate their turnover" by Rasulova (USSR) provide ex- amples of the wide range of problems contained in this section.

Quite different in content and approach are the papers collected in the second section. Several papers develop the idea of the implementation of decision support systems and computer aided management systems. Integrated multistage inven- tory systems are studied and the information flow as a foundation of stock management is discussed. As usual in the inventory literature ordering poli- cies play some role and consequences from imple- menting MRP or JIT strategies are evaluated. The papers "On reducing excessive stock in the order- level lot-size system for decaying inventories" by Dave (United Kingdom) or "Decision support systems for management in central warehouses of building plants" by Ehrenberg (GDR) are exam- ples of the many presentations aiming at an ana- lytic study of inventory problems and at the use of up-to-date computer science approaches.

New models, algorithms and spheres of appli- cation are studied in the papers of the third sec- tion. New models cover problems of pricing, sensi- tivity, rolling schedules, multicriteria decisions and others. Many papers as for instance "Initial order quantities" by Axs~iter (Sweden), "A practical near-optimal order quantity method" by Mabin (New Zealand) or "Optimal stock-out timing in a

dynamic model with full backordering" by Whitin (USA) try to provide such algorithms or analytic formulae which can be implemented easily. Other mathematical studies of several inventory prob- lems by Bulinskaya (USSR), Hartl (Austria) or Kehayov (Bulgaria) are of theoretical interest to Operations Research and Optimization people.

The reader interested in Production Economics, Inventory Management, Production Systems, Management Science and Operations Research will find in this book original papers written by lead- ing scholars. Certainly some of the papers will meet his expectations.

Knut R I C H T E R Technische Universitiit Chemnitz

P S F 964 Chemnitz 9010 Chemnitz

DDR

J. BRYANT

Problem Management

Wiley, Chichester, 1989, viii + 340 pages, £24.95

The central idea of this book is that many problems cannot simply be solved. The very defi- nition of the problem, the acceptability of possible approaches, and the later consequences of present action all vary with the observer's point of view. Even when consensus is attained, today's solutions have a way of generating tomorrow's problems. Rather than simplistic 'problem-solving', then, Bryant urges us to learn the art and science of long-term problem management.

The author says he got this idea from some colleagues in operational research. I must confess some astonishment at this, since the operational researchers I know regard themselves, virtually without exception, as problem-solvers par excel- lence. To me, his ideas and his language seem to owe more to popular psychology, and perhaps to Zen and the human-potential movement, than to O R / M S . Certainly the reader expecting a manager's or management scientist's overview of how to tackle problems will be surprised, and most likely disappointed, to learn early on that "this book is not about solving problems".

Instead, we explore how problems are defined