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System enquiry: A system dynamics approach
386
European Journal of Operational Research 52 (1991) 386-392 North-Holland
Book Reviews Eric F. Wolstelholme
System Enquiry: A System Dynamics Approach John Wiley & Sons, Chichester, 1990, xi + 238 pages, £16.50, ISBN 0-471-92783-X This is an excellent, well-balanced book which fills a much needed gap in the systems literature. It describes, updates, expands and applies the system dynamics methodology, both as a qualitative and quantitative concept. The qualitative approach is particularly novel and powerful. It has similarities to the soft syste-m problem solving methodologies currently in vogue for knowledge acquisition and structuring in complex systems, but has the added potential of allowing fast conversion of ideas and diagrams into more rigorous simulation models. The text is logically laid out and covers background material and definitions for those unfamiliar with the terminology of, and need for, systems methods. The author has gone to considerable efforts to devise a new, modular approach to assist with the conceptualisation, development and analysis of models. This is well described and applied to all the case studies in the book. Of particular note is the focus placed on the need for the total involvement of the system owners in the creation of models and the bold stance taken on the purpose of modelling. Emphasis is placed as much on learning from the process of modelling as on the outcome. It is reasoned that a wide definition of validity and forecasting is necessary when dealing with system evolution over the long term, where past structures might not apply and concern is more centred on the shape of organisational change rather than any attempt at accurate prediction. The ideas of simulation are introduced at a basic level, but sufficient detail is provided for understanding of the quantitative cases studies. Full equation listings of these cases are provided in appendices and the formulation of small sectors of each model are given in the text. It is gratifying to see the application of two current pieces of
software for system dynamics modelling (DYSMAP2 and Stella), which helps to dispel any idea that the approach is software specific. The case material covers a wide range of systems (including mining, defence, business, health and personal social services) and each case is comprehensively designed to bring out a different insight and aspect of the method. These include the trade off between capacity and control, counter intuitive behaviour and the isomorphic nature of m a n y systems. Of major significance are the two chapters on optimisation of system dynamics models. The basis of optimisation by simulation is described and the additional policy insights offered by optimising models is demonstrated by applying the concept to one of the earlier case studies. The book is, effectively, a write up of Eric Wolstenholme's extensive experiences in developing and applying the system dynamics methods and reflects his close association with the practice of this subject on a world wide basis. Perhaps the book can be criticised for covering to much material, but there is something of interest here for both the planner and the analyst. Robert K. Holmes S R H Associates Castle House, 1 Castle Hill, Fell Lane Keighley West Yorkshire BD22 6BD, UK
G r a h a m Winstanley (ed.)
Artificial Intelligence in Engineering John Wiley, Chichester, 1991, xii + 434 pages This book is the result of the collaboration of twelve authors, eight of them are from Brighton Polytechnic. The title of this book, Artificial Intelligence in Engineering, is very broad, leaving room for many possible interpretations and expectations. The authors describe their book as dealing with the fundamental and practical issues involved
0377-2217/91/$03.50 © 1991 ElsevierScience Publishers B.V. (North-Holland)
European Journal of Operational Research 52 (1991) 386-392 North-Holland
Book Reviews Eric F. Wolstelholme
System Enquiry: A System Dynamics Approach John Wiley & Sons, Chichester, 1990, xi + 238 pages, £16.50, ISBN 0-471-92783-X This is an excellent, well-balanced book which fills a much needed gap in the systems literature. It describes, updates, expands and applies the system dynamics methodology, both as a qualitative and quantitative concept. The qualitative approach is particularly novel and powerful. It has similarities to the soft syste-m problem solving methodologies currently in vogue for knowledge acquisition and structuring in complex systems, but has the added potential of allowing fast conversion of ideas and diagrams into more rigorous simulation models. The text is logically laid out and covers background material and definitions for those unfamiliar with the terminology of, and need for, systems methods. The author has gone to considerable efforts to devise a new, modular approach to assist with the conceptualisation, development and analysis of models. This is well described and applied to all the case studies in the book. Of particular note is the focus placed on the need for the total involvement of the system owners in the creation of models and the bold stance taken on the purpose of modelling. Emphasis is placed as much on learning from the process of modelling as on the outcome. It is reasoned that a wide definition of validity and forecasting is necessary when dealing with system evolution over the long term, where past structures might not apply and concern is more centred on the shape of organisational change rather than any attempt at accurate prediction. The ideas of simulation are introduced at a basic level, but sufficient detail is provided for understanding of the quantitative cases studies. Full equation listings of these cases are provided in appendices and the formulation of small sectors of each model are given in the text. It is gratifying to see the application of two current pieces of
software for system dynamics modelling (DYSMAP2 and Stella), which helps to dispel any idea that the approach is software specific. The case material covers a wide range of systems (including mining, defence, business, health and personal social services) and each case is comprehensively designed to bring out a different insight and aspect of the method. These include the trade off between capacity and control, counter intuitive behaviour and the isomorphic nature of m a n y systems. Of major significance are the two chapters on optimisation of system dynamics models. The basis of optimisation by simulation is described and the additional policy insights offered by optimising models is demonstrated by applying the concept to one of the earlier case studies. The book is, effectively, a write up of Eric Wolstenholme's extensive experiences in developing and applying the system dynamics methods and reflects his close association with the practice of this subject on a world wide basis. Perhaps the book can be criticised for covering to much material, but there is something of interest here for both the planner and the analyst. Robert K. Holmes S R H Associates Castle House, 1 Castle Hill, Fell Lane Keighley West Yorkshire BD22 6BD, UK
G r a h a m Winstanley (ed.)
Artificial Intelligence in Engineering John Wiley, Chichester, 1991, xii + 434 pages This book is the result of the collaboration of twelve authors, eight of them are from Brighton Polytechnic. The title of this book, Artificial Intelligence in Engineering, is very broad, leaving room for many possible interpretations and expectations. The authors describe their book as dealing with the fundamental and practical issues involved
0377-2217/91/$03.50 © 1991 ElsevierScience Publishers B.V. (North-Holland)