Models and methods

Every once in a while, a clever text comes along that breathes a nice dose of fresh air into the mature field of Operations Research (OR). The Jensen and Bard book is one such welcome example. Its intent, successfully achieved, is to bridge the gap between OR theory and practice. This goal is accomplished through: (i) the text’s well-thought-out organizational structure; (ii) an accompanying CD containing supplemental support material and software; and (iii) the website www.ormm. net, where we find a great deal of additional material for both the instructor and student. The book is suitable for senior-level or first-year graduate students in engineering curricula, and perhaps for MBA students as well. The level of the material is a bit higher than that found in Winston (1994), Hillier and Lieberman (2002) and Taha (2002). In addition, the text can be adapted for either a oneor two-semester course, and it is virtually selfcontained, so most students should be able to jump right in and use this text. Loosely speaking, the book is split into deterministic and stochastic portions. After an introductory discussion on OR problem-solving (Chapter 1), the first main portion tackles general OR techniques, including extensive discussions on linear programming models and methods (Chapters 2–4). It then undertakes network flow programming and integer programming models and methods (Chapters 5–8), followed by the more-advanced topic of nonlinear programming (Chapters 9 and 10). The portion on stochastic processes includes general modeling in a stochastic environment (Chapter 11), discrete-time Markov chains (Chapters 12 and 13), continuous-time Markov chains (Chapters 14 and 15), queueing models (Chapters 16 and 17), and computer simulation (Chapter 18). The approach for each topic area is to provide solid motivation via a variety of models and applications, while backing up these real-world examples with the necessary theory and methodology. Indeed, many of the topics are treated in twin chapters for models and methods. I believe that this organizational structure lends the reader a full view of the relationships among modeling, analysis, implementation issues, and decision making; it also allows the instructor to easily tailor the course for the particular student audience. The CD that is included with the text contains numerous Excel add-ins that support and supplement the models and methods discussed in the text. The add-ins are very simple to apply, provide quite a bit of motivation, solve most of the text’s examples, and can be used for most of the problems at the end of the chapters. The CD also contains substantial material on certain advanced topics; for instance, one can find a complete treatment on dynamic programming models and methods. The CD houses three commercial software packages referenced in the text: an enhanced version of Excel’s optimization engine (Premium Solver for Education, from Frontline Systems), a graphical model development environment for building mathematical optimization models (MPL Modeling System, from Maximal Software), and a popular discrete-event simulation package (Extend, from Imagine That, Inc.). A special Instructor’s CD is available from the publisher for those who adopt the book. This CD contains the solutions to all the exercises at the end of the chapters, Powerpoint presentations for many of the chapters, and other relevant teaching material. The web site is impressive, both for its content and ease of navigation. It provides supplemental readings, software updates, software demonstrations, teaching aids, and additional examples and exercises, most of which utilize the many Excel add-ins. A typical example that one can download is a demonstration Excel file suitable for illustrating transportation problems; students can input costs, supplies, and demands, and then push a button to start up the simplex solution. Another series of demonstrations concerns simulation with respect to a variety of problems ranging from time series analysis to production and inventory planning to mortgage calculations. Bulletin boards are also available to students and faculty. A teacher could almost base a course solely on the material to be found at the website. To summarize, I feel that the book is extremely wellwritten, interesting, and unique among OR texts; it certainly approaches the topic areas from a new perspective. This is an excellent text that I believe professors and students will enjoy and gain a lot from its use.