This concept paper investigates possibilities to detect terrorist cells based on communications between individuals without the need for wiretapping. The advantages of such procedure are apparent: fewer (if any) legal requirements, and, most importantly, the possibility to automate the surveillance. After a brief review of the pertinent literature, we offer three approaches that are designed to aid in the detection of not only terrorist cells, but also the command structures within the cells. The techniques are demonstrated by using a small illustration. The paper concludes by outlining limitations of the procedures described here.

Almost everywhere, routing plays an important role in everyday life. This thesis consists of three parts, each studying different applications where routing decisions are coordinated with other decisions. A common denominator in all applications is that an intelligent utilization of a fleet of vehicles is crucial for the performance of the system. In the first part, routing and inventorymanagement decisions are coordinated, in the second part, routing decisions concerning different modes of transportation are coordinated with inventory management, and in the third part, location decision and routing are coordinated. In the first part, an application concerning waste management is presented. Many industries generate garbage, and instead of handling the waste disposal themselves, other companies, specialized in garbage collection, handle the disposal. Each industry rents containers from a company to be used for waste, and the garbage collection companies handle the collection. The industries buy a service including one or more containers at the industry and the garbage collection companies are obliged to make sure that the containers never become overfull. The idea is that the industries buy this service and in return, the garbage collection company can plan the collection so that the overall cost and the number of overfull containers is minimized. Two models for the problem facing the garbage collection company are proposed. The first is solved using a Lagrangean relaxation approach on a flow based model, and the second is solved using Benders decomposition on a column based model. The second part investigates a distribution chain management problem taken from the Swedish pulp industry. Given fixed production plans at the mills, and fixed customer demands, the problem is to minimize the distribution cost. Unlike many other models for marine distribution chains, the customers are not located at the harbors. This means that the model proposed also incorporates the distribution planning from the harbors to the customers. All customers are not served from the harbors; some are served directly from the mills using trucks and trains to distribute the pulp, and these decisions are also included. The problem is modeled as a mixed integer linear program and solved using a branch and price scheme. Due to the complexity of the problem, the solution strategy is divided into two phases, where the first emphasizes the generation of schedules for the vessels operated by the company, while the second deals with the chartering of vessels on the spot market. In the third part, routing is combined with location decisions in the location-routing problem. Special emphasis is given to strategic management where decision makers must make location, capacity and routing decisions over a long planning period. The studied application comes fromstrategic schoolmanagement, where the location and capacity of the schools as well as their catchment areas are under consideration. The problem is modeled as a mixed integer linear program. The computational study shows the importance of incorporating a routing component allowing multiple visits, as well as the danger of having a too short planning period.

This paper describes remote probing, a method that employs the principle of external pivoting and evaluates points with respect to their objective values from a given basic point, i.e., without ever moving out of that basic point. Once a point is deemed sufficiently good, the method moves to that point in a single simplex step, and from there on, the regular primal simplex method commences. In that sense, remote probing can be seen as preprocessing for the primal simplex algorithm.

This paper examines the results of a survey concerning some aspects of quantitative courses offered by North American business schools. In particular, we look at the proliferation of statistics, operations research, and production and operations management courses as well as specific operations research topics and their coverage in undergraduate curricula. This information is analysed and compared to the use of operations research models and techniques in practice as reported in the literature.

This paper describes a model for allocating the weekly requirement of manpower for maintenance jobs in the process units. We develop a simple procedure for the solution of the manpower allocation problem which has to deal with planned and unplanned jobs during a planning period. The solution procedure is illustrated by a numerical example. Possible extensions of this model are also discussed.

A problem frequently faced by shopping center planners is how to locate the shops in relation to one another. A natural objective is to achieve a suitable level of pedestrian movement throughout the center, and a good layout will increase overall profitability. This requires the knowledge of pedestrian flows between pairs of shops, by itself a difficult problem. Given the relevant data is available, the optimal layout problem is a hard combinatorial optimization problem. If the shopping center is linear, it is akin to a large scale seriation problem. We present a dynamic programming algorithm for this case, as well as a greedy heuristic. This heuristic is adapted to the case of tree-shaped shopping centers. It is illustrated on a numerical example.

SYNOPTIC ABSTRACTIn this review article we first examine the early contributions to the field of location problems. Then some of the difficulties arising in the application of location models are discussed. We conclude with a synopsis of studies that describe instances in which location models were used to solve real-world problems.

In this paper transportation problems with minimax objective are studied. It is shown that it can be decided in linear time whether reshipments and overshipments can improve the solution. Moreover, new algorithms are stated which solve even the lexicographic version of the underlying minimax transportation, reshipment and overshipment problems. The first two problems can be solved by an algorithm of time complexityO(n2), wheren is the number of origins and destinations, whereas the overshipment problem is solved in linear time. Moreover, some extensions of the problems are addressed.

In this paper we first survey a spatial concept called Voronoi diagrams. The basic properties of these diagrams are described and some possible extensions are outlined. We then delineate a variety of traditional and potential new applications of Voronoi diagrams in the business environment. Cet article étudie un concept spatial, les diagrammes de Voronoi. Les propriétés élémentaires de ces diagrammes sont relatées et des extensions possibles sont esquissées. Une variété de nouvelles applications, traditionnelles et potentielles, des diagrammes de Voronoi dans le monde des affaires sont ensuite décrites.