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Continuous location of transportation networks
Book Reviews
and shows how to computerise standard balance sheets. In Chapter 6 on Business Forecasting, the author demonstrates how to analyse historical sales information and then predict future performance. Two initial examples are used to show how to fit linear and exponential models respectively to the given data. The first example is then expanded to show how to calculate and display moving average data, identify trends, and then forecast. A further example illustrates the use of the highly powerful and automatic data regression function of LOTUS to quantify dependence of variables and assess goodness-of-fit. Decision models are covered in Chapter 7, and the model described revolves around the LOTUS functions @ I F , @ M A X . The coding is neat and c o n c i s e - - a n unusual application for the package. Chapter 8 goes on to consider the use of macros. These are series of commands stored as text strings in individual cells which can then be activated instantly with 2 keys. They are highly powerful and are demonstrated through an automatic letter writing model. Data tables are used to hold names, addresses and the specific details (which can all be the result of calculations, themselves), and then macros are used to fill the letter p r o f o r m a from the tables. The approach seems similar to, say, Wordstar's mailmerge facility. Chapter 9 is by far the most complex, and addresses simulation. To assess likely return from a promotion, a sales model is developed which includes random elements via the @ R A N D function. This allows the modelling of a company performance including uncertainty. Very impressive hierarchical menu-driven control is even derived from nested macros. A final example uses a similar approach to investigate whether a company should launch a new product. In summary, the book is a good addition to the literature. The text is painstakingly complete and accurate, and is very easy to follow. It is written very much for people with real problems to solve, and this is always very refreshing. The bulk of the book is perhaps aimed at the middle ground rather than really advanced users, but probably there will be very few who do not find some new tricks in it.
Andrew TOBIAS University of Birmingham Birmingham, England
271
K.C. M O S L E R Continuous Location of Transportation Networks Series of Texts and Monographs in Economics and Mathematical Systems, M.J. Beckmann and W. Krelle (eds.) Springer, Berlin, 1987, XX + 158 pages, DM58,00 This brief book is concerned with the design and location of transportation links, junctions and facilities in a (possibly anisotropic) travel environment in the plane. It provides an overview of an approach to this subject favored by a number of economists, including Martin Beckmann and Tony Puu with both of whom Professor Mosler has worked closely. This volume is an expanded and reworked version of the earlier monograph Opti-
male Transportnetze, zur Bestimmung ihres kostengunstigsten Standorts bei gegebener Nachfrage, published in 1976 (Springer Lecture Notes in Economics and Mathematical Systems, No. 125). The book consists of six chapters. The first gives a brief introduction, including a nice overview of the contents of the five main chapters. Chapter I1 ("Transport Lines") presents the fundamental mathematics of designing a single transport link between a single origin and a single destination in isotropic and anisotropic travel media, given a cost function that depends on location and direction. The objective is to find the link which joins the origin with the destination at minimum cost. Chapter llI is concerned with finding an optim u m network (which, given the geometries and questions examined, always happens to be a tree) for discretely and continuously distributed transportation demands. The emphasis is on cases with continuously distributed demands traveling to a single common destination. The next two chapters examine the specific problem of designing a transportation network in a circular area with a single destination and with either isotropic (Chapter IV) or anisotropic (Chapter V) transport. Both chapters devote considerable space to a discussion of bifurcated transport lines and also cover a significant number of variations on the topic's principal theme. Finally, Chapter VI contains a brief discussion of idealized network structures in a multi-origin, multi-destination environment. Under the modeling assumptions of this chapter, these networks take the form of grids made up of regular polygons.
Book Reviews
272
The book has both strengths and weaknesses. Strengths include: a nice and logical presentation of the mathematical arguments (the principal mathematical tools are analytic geometry and calculus, including the calculus of variations); good illustration of the basic concepts with the aid of simple geometrical sketches; and informative reviews of the relevant literature, including several interesting historical perspectives. The principal deficiency is the lack of in-depth discussion on the relationship between the concepts presented and the problems encountered in transportation practice. While the author does acknowledge in the introduction that the approach described must be only 'one of several approaches' and that 'practical limitations have to be examined' in parallel, the gap between this body of theory and the true needs of the designers of transportation networks requires far more attention than it receives here. Other weaknesses include the fact that Chapter V I - - t h e only one where more complex network configurations are discussed--is rather perfunctory and the dry theorem-followed-by-proof format of presentation. Finally, the text would have benefitted from additional proofreading and some editing to correct or modify some awkward-sounding (in English) sentences. In summary, this scholarly book should be useful to those economists and operations researchers in the research and academic communities which are interested in this type of mathematical approach and modeling. A recommended companion volume is G.F. Newell's, Traffic Flow on Transportation Networks, The MIT Press, Cambridge, MA, 1980, which presents analogous concepts in a more informal style that emphasizes intuitive insights.
Amedeo R. ODONI Operations Research Center Massachusetts Institute of Technology Cambridge, USA
J.P. OSLEEB and S.J. R A T I C K (eds.)
~tional tions
Decisions: Methodology and Applica-
Annals of Operations Research, Vol. 6, Baltzer, Basel, 1986, 328 pages
This volume consists of 18 articles, selected among the papers which were presented at the Third International Symposium on Locational Decisions, ISOLDE III, held in Boston, USA, during the Summer 1984. It is thus part of a well established symposium series of which the fourth has already taken place in Namur, Belgium, 1987. The first symposium, held in Banff, Alberta, Canada in 1978, was organized by Jonathan Halpern, who died unexpectedly early in 1981. The current volume is dedicated to him and includes a listing of his professional activities and works. The articles have been categorized under the following 10 head lines: "Covering problems. Solving p-median problems. Spatial network equilibria. Competitive locations. Center locations and related problems. Location-allocation applications. Locations with spatial nodes and continuous link demands. Hierarchical location problems. Location routing problems. Dynamic location problems". A majority of the articles consider discrete location models built on or inspired by the fundamental median and center location problems in graphs. These classical models, and with them many location studies, assume demands to be fixed in advance. It is interesting to note that the current volume contains several articles dealing with questions like stochastic demands, the size of demand as a function of actual facility location, moving demands etc. Most of the articles are of a theoretical nature. However, a couple of articles include models of practical location problems together with some numerical results and decision proposals. In total, the articles appear to be quite representative for the current development of the discipline. It is in this context pleasant to note the occurrence of an increasing flexibility in modelling principles as well as in data requirements. Since most articles are fairly specialized the volume will be of greatest interest to people who are already working in the field. However, as such it can be highly recommended as a useful source for research projects as well as for advanced education in the area.
Jorgen TIND University of Aarhus Denmark
and shows how to computerise standard balance sheets. In Chapter 6 on Business Forecasting, the author demonstrates how to analyse historical sales information and then predict future performance. Two initial examples are used to show how to fit linear and exponential models respectively to the given data. The first example is then expanded to show how to calculate and display moving average data, identify trends, and then forecast. A further example illustrates the use of the highly powerful and automatic data regression function of LOTUS to quantify dependence of variables and assess goodness-of-fit. Decision models are covered in Chapter 7, and the model described revolves around the LOTUS functions @ I F , @ M A X . The coding is neat and c o n c i s e - - a n unusual application for the package. Chapter 8 goes on to consider the use of macros. These are series of commands stored as text strings in individual cells which can then be activated instantly with 2 keys. They are highly powerful and are demonstrated through an automatic letter writing model. Data tables are used to hold names, addresses and the specific details (which can all be the result of calculations, themselves), and then macros are used to fill the letter p r o f o r m a from the tables. The approach seems similar to, say, Wordstar's mailmerge facility. Chapter 9 is by far the most complex, and addresses simulation. To assess likely return from a promotion, a sales model is developed which includes random elements via the @ R A N D function. This allows the modelling of a company performance including uncertainty. Very impressive hierarchical menu-driven control is even derived from nested macros. A final example uses a similar approach to investigate whether a company should launch a new product. In summary, the book is a good addition to the literature. The text is painstakingly complete and accurate, and is very easy to follow. It is written very much for people with real problems to solve, and this is always very refreshing. The bulk of the book is perhaps aimed at the middle ground rather than really advanced users, but probably there will be very few who do not find some new tricks in it.
Andrew TOBIAS University of Birmingham Birmingham, England
271
K.C. M O S L E R Continuous Location of Transportation Networks Series of Texts and Monographs in Economics and Mathematical Systems, M.J. Beckmann and W. Krelle (eds.) Springer, Berlin, 1987, XX + 158 pages, DM58,00 This brief book is concerned with the design and location of transportation links, junctions and facilities in a (possibly anisotropic) travel environment in the plane. It provides an overview of an approach to this subject favored by a number of economists, including Martin Beckmann and Tony Puu with both of whom Professor Mosler has worked closely. This volume is an expanded and reworked version of the earlier monograph Opti-
male Transportnetze, zur Bestimmung ihres kostengunstigsten Standorts bei gegebener Nachfrage, published in 1976 (Springer Lecture Notes in Economics and Mathematical Systems, No. 125). The book consists of six chapters. The first gives a brief introduction, including a nice overview of the contents of the five main chapters. Chapter I1 ("Transport Lines") presents the fundamental mathematics of designing a single transport link between a single origin and a single destination in isotropic and anisotropic travel media, given a cost function that depends on location and direction. The objective is to find the link which joins the origin with the destination at minimum cost. Chapter llI is concerned with finding an optim u m network (which, given the geometries and questions examined, always happens to be a tree) for discretely and continuously distributed transportation demands. The emphasis is on cases with continuously distributed demands traveling to a single common destination. The next two chapters examine the specific problem of designing a transportation network in a circular area with a single destination and with either isotropic (Chapter IV) or anisotropic (Chapter V) transport. Both chapters devote considerable space to a discussion of bifurcated transport lines and also cover a significant number of variations on the topic's principal theme. Finally, Chapter VI contains a brief discussion of idealized network structures in a multi-origin, multi-destination environment. Under the modeling assumptions of this chapter, these networks take the form of grids made up of regular polygons.
Book Reviews
272
The book has both strengths and weaknesses. Strengths include: a nice and logical presentation of the mathematical arguments (the principal mathematical tools are analytic geometry and calculus, including the calculus of variations); good illustration of the basic concepts with the aid of simple geometrical sketches; and informative reviews of the relevant literature, including several interesting historical perspectives. The principal deficiency is the lack of in-depth discussion on the relationship between the concepts presented and the problems encountered in transportation practice. While the author does acknowledge in the introduction that the approach described must be only 'one of several approaches' and that 'practical limitations have to be examined' in parallel, the gap between this body of theory and the true needs of the designers of transportation networks requires far more attention than it receives here. Other weaknesses include the fact that Chapter V I - - t h e only one where more complex network configurations are discussed--is rather perfunctory and the dry theorem-followed-by-proof format of presentation. Finally, the text would have benefitted from additional proofreading and some editing to correct or modify some awkward-sounding (in English) sentences. In summary, this scholarly book should be useful to those economists and operations researchers in the research and academic communities which are interested in this type of mathematical approach and modeling. A recommended companion volume is G.F. Newell's, Traffic Flow on Transportation Networks, The MIT Press, Cambridge, MA, 1980, which presents analogous concepts in a more informal style that emphasizes intuitive insights.
Amedeo R. ODONI Operations Research Center Massachusetts Institute of Technology Cambridge, USA
J.P. OSLEEB and S.J. R A T I C K (eds.)
~tional tions
Decisions: Methodology and Applica-
Annals of Operations Research, Vol. 6, Baltzer, Basel, 1986, 328 pages
This volume consists of 18 articles, selected among the papers which were presented at the Third International Symposium on Locational Decisions, ISOLDE III, held in Boston, USA, during the Summer 1984. It is thus part of a well established symposium series of which the fourth has already taken place in Namur, Belgium, 1987. The first symposium, held in Banff, Alberta, Canada in 1978, was organized by Jonathan Halpern, who died unexpectedly early in 1981. The current volume is dedicated to him and includes a listing of his professional activities and works. The articles have been categorized under the following 10 head lines: "Covering problems. Solving p-median problems. Spatial network equilibria. Competitive locations. Center locations and related problems. Location-allocation applications. Locations with spatial nodes and continuous link demands. Hierarchical location problems. Location routing problems. Dynamic location problems". A majority of the articles consider discrete location models built on or inspired by the fundamental median and center location problems in graphs. These classical models, and with them many location studies, assume demands to be fixed in advance. It is interesting to note that the current volume contains several articles dealing with questions like stochastic demands, the size of demand as a function of actual facility location, moving demands etc. Most of the articles are of a theoretical nature. However, a couple of articles include models of practical location problems together with some numerical results and decision proposals. In total, the articles appear to be quite representative for the current development of the discipline. It is in this context pleasant to note the occurrence of an increasing flexibility in modelling principles as well as in data requirements. Since most articles are fairly specialized the volume will be of greatest interest to people who are already working in the field. However, as such it can be highly recommended as a useful source for research projects as well as for advanced education in the area.
Jorgen TIND University of Aarhus Denmark