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An exact solution method for the graph bisection problem is presented. We describe a branch-and-bound algorithm which is based on a cutting plane approach combining semideenite programming and polyhedral relax-ations. We report on extensive numerical experiments which were performed for various classes of graphs. The results indicate that the present(More)
Quadratic Assignment problems are in practice among the most diicult to solve in the class of NP-complete problems. The only successful approach hitherto has been Branch-and-Bound-based algorithms, but such algorithms are crucially dependent on good bound functions to limit the size of the space searched. Much work has been done to identify such functions(More)
The airline industry is notably one of the success stories with respect to the use of optimization based methods and tools in planning. Both in planning of the assignment of available aircraft to flights and in crew scheduling, these methods play a major role. Plans are usually made several months prior to the actual day of operation. As a consequence,(More)
This paper deals with disruption management in passenger railway transportation. In the disruption management process, many actors belonging to different organizations play a role. In this paper we therefore describe the process itself and the roles of the different actors. Furthermore, we discuss the three main subproblems in railway disruption management:(More)
The Best-First Search strategy (BeFS) and the Depth-First Search strategy (DFS) are regarded as the prime strategies when solving combinatorial optimization problems by parallel Branch-and-Bound (B&B) – BeFS because of efficiency with respect to the number of nodes explored, and DFS for reasons of space efficiency. We investigate the efficiency of both(More)
Job-Shop Scheduling (JSS) problems are among the more diicult to solve in the class of NP-complete problems. The only successful approach has been Branch-and-Bound based algorithms, but such algorithms depend heavily on good bound functions. Much work has been done to identify such functions for the JSS problem, but with limited success. Even with recent(More)
Deep brain stimulation (DBS) is a clinically established procedure for treating severe motor symptoms in patients suffering from end-stage Parkinson's disease, dystonia and essential tremor. Currently, it is tested for further indications including psychiatric disorders like major depression and a variety of other diseases. However, ethical issues of DBS(More)
Over the past decade, cross-docking has emerged as an important material handling technology in transportation. A variation of the well-known Vehicle Routing Problem (VRP), the Vehicle Routing Problem with Cross-Docking (VRPCD) arises in a number of logistics planning contexts. This paper addresses the VRPCD, where a set of homogeneous vehicles are used to(More)