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Operations Research Models and Methods


Material on this Site

The site contents are organized under the five general headings of Models, Methods, Computation, Problems, and Operations Management/Industrial Engineering (OM/IE) .  The Models section contains brief discussions on how decision problems can be expressed in a form amenable to analysis, along with examples. The section includes most of the topics considered by introductory Operations Research courses. The Methods section contains pages that explain the theoretical constructs behind the solution methods, primarily mathematical programming. The Computation section provides instructions for the Excel add-ins that can be used to solve the models.  A large variety of OR methods are implemented with the Excel add-ins. The Problems section has modeling or algorithm problems to be solved by the student. The OM/IE section has pages discussing the design and operation of manufacturing systems. These topics are typically taught in operations management and industrial engineering academic programs. Additional add-ins solve applied problems in OM/IE.

The site includes what might be considered a horizontal structure in the form of Tours.  A tour spans all five general areas and could be constructed, for example, for an integer programming course or for a stochastic methods course. Several course outlines with links to supporting pages are provided in an Instruction section.

The site includes two sections that are composed of Excel documents. The first gives access to the Excel add-ins that implement almost all the computational procedures described and used in introductory textbooks on Operations Research and Operations Management. The add-ins have been extensively tested and are particularly easy to use.  The second section provides Excel workbooks that contain demonstrations of the procedures of the add-ins. The models used are generally those described in the add-in documentation. A related page holds answers to Frequently Asked Questions.

All the subjects considered have a large literature of publications by researchers. It would be difficult to give credit to the many who have contributed by their works to the materials on this site, so in most cases we have not attempted to do so. Most of the theory implemented in the add-ins is well known and available from a variety of sources. The interested student should read the specialized textbooks and journal articles available for every topic considered here.

The add-ins implement methods that solve problems, but we have not attempted to use the most efficient or accurate methods. We have attempted to consider a broad range of models and methods, rather than treat only a few with great depth. The person requiring more effective software should contact commercial vendors.


Purpose of the Site


Most students will enjoy the OR Models section. Here are surveys of most of the topic areas that would be covered in an Introduction to Operations Research course, as well as more advanced courses. In the Methods section students will find demonstrations of the primal simplex algorithms for both general linear programming and network flow programming. Add-ins specifically dedicated to teaching are provided for: Linear Programming, Transportation Problem, Network Flow Programming, Integer Programming, Nonlinear Programming and Dynamic Programming. These can be operated in either demonstration mode for illustration or instruction mode for practice. In the Add-ins section and the associated Computation section students will find computational methods that can be applied to most numerical textbook problems. The Problems section provides practice problems, some with answers. Students interested in Operations Management or Industrial Engineering will find in the OM/IE section discussions and add-ins appropriate for a number of problems that arise in these fields.


Although the site was written to support the authors' book, Operations Research Models and Methods, it will be useful for almost any introductory text book. The site does not provide complete mathematical background to the topics considered. We assume that will be provided by a textbook. Teachers will find many resources to support teaching. The Instruction section provides resources for several courses including PowerPoint presentations. One of the main benefits of using add-ins for the teacher is the ability to create examples and homework problems that are more interesting than the usual textbook problems. Several of the algorithmic add-ins provide outputs that help explain the processes used to solve problems.


The add-ins will be particularly interesting to persons practicing Operations Research. Many times it is useful to test concepts on small problems before extensive programming or the purchase of off-the-shelf software. The add-ins cover a great variety of problems and they are very easy to use. The VBA code is easily accessible, so practitioners can modify the add-ins or create new ones.

Relation to the Book

This site supports the book Operations Research Models and Methods, published by John Wiley and Sons in 2003. Some of the materials in this site are included on a CD that accompanies the book. An Errata page provide corrections to the text and CD contents and provide access to the Excel add-ins and other supporting materials for those not using the text. We hope, of course, that persons who find the site useful will buy the book. To purchase the book or request faculty examination copies visit the John Wiley site.

The book is designed to bridge the gap between theory and practice by presenting the tools and techniques most suited for modern operations research.  A principal goal is to give engineers, analysts, and decision makers a larger appreciation of the role of OR by providing examples of its applications and the basics of its theoretical development.

Topics are structured along functional lines and span mathematical programming, stochastic processes, and simulation.  The presentation is designed to give a full picture of the relationships that exist among modeling, analysis, computations, algorithmic implementation, and decision-making.  The first part of the book is devoted to deterministic optimization.  Separate chapters are included on models and methods for each topic.  By separating models and methods in a formal way, those whose main interests do not lie in the mathematics of operations research can study the modeling material without intimidation.  For those who have the motivation or need to understand the mathematics, a simple but rigorous development of OR methods is provided.  The second part of the book deals with probabilistic systems and is similarly structured.  In a number of cases, though, it made more sense to integrate models and theory in a particular area into a single chapter rather than treat them in separate chapters.

Computational support is an integral component of the book. The algorithms embodied in the Excel add-ins are quite robust and extremely easy to use.  For the most part, they reflect the procedures outlined in the text. When the user enters the data and selects a solution process, results are automatically computed and presented on the spreadsheet.  Very little instruction is necessary for the user to input and solve complex problems.  The spreadsheet medium is very useful because most people are familiar with its basic operations, data analysis can be in the same file as models and solutions, several OR methods can interact through the common interface, and data can be easily modified for what-if analysis.

Paul A. Jensen, 2004


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Operations Research Models and Methods
by Paul A. Jensen
Copyright 2004 - All rights reserved