Kenneth Sörensen

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In recent years, the field of combinatorial optimization has witnessed a true tsunami of “novel” metaheuristic methods, most of them based on a metaphor of some natural or man-made process. The behavior of virtually any species of insects, the flow of water, musicians playing together – it seems that no idea is too far-fetched to serve as inspiration to(More)
In this paper, we develop and discuss several distance measures for permutation type representations of solutions of combinatorial optimisation problems. The problems discussed include single-machine and multiple-machine scheduling problems, the travelling salesman problem, vehicle routing problems, and many others. The distance measures are based on the(More)
Determining the optimal number and location of intermodal transshipment terminals is a decision that strongly influences the viability of the intermodal transportation alternative. In this paper, we develop a model and an optimization method that provides policy makers with a tool to help them take these decisions. 5 The objective of the terminal location(More)
A production line is studied with several machines in series. The machines are separated with finite buffers. They can break down and have to be repaired. Production is assumed to be continuous, i.e. no individual products can be identified. Analytical models for such a system are scarce. Analytical results for the throughput can be obtained only under very(More)
This paper introduces a fast solution procedure to solve 100-node instances of the time-dependent orienteering problem (TD-OP) within a few seconds of computation time. Orienteering problems occur in logistic situations were an optimal combination of locations needs to be selected and the routing between the selected locations needs to be optimized. In the(More)
A minimum spanning tree of an undirected graph can be easily obtained using classical algorithms by Prim or Kruskal. A number of algorithms have been proposed to enumerate all spanning trees of an undirected graph. Good time and space complexities are the major concerns of these algorithms. Most algorithms generate spanning trees using some fundamental cut(More)