Stefan Tschöke

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This paper is the rst to present a parallelization of a highly eecient best-rst branch-and-bound algorithm to solve large symmetric traveling salesman problems on a massively parallel computer containing 1024 processors. The underlying sequential branch & bound algorithm is based on 1-tree relaxation introduced by Held and Karp (Lagrangean approach) and(More)
To solve real-world discrete optimization problems approximately metaheuristics such as simulated annealing and other local search methods are commonly used. For large instances of these problems or those with a lot of hard constraints even fast heuristics require a considerable amount of computational time. At the same time, especially for sensitivity(More)
In this paper we present a new parallelization of an efficient best-first branch-and-bound algorithm to solve the constrained two-dimensional single stock guillotine cutting stock problem (CSP) to optimality. The underlying sequential branch-and-bound algorithm is based on an exact version of Wang's heuristic suggested by Viswanathan and Bagchi. In our(More)
Load distribution is essential for eecient use of processors in parallel branch-and-bound computations because the computation generates and consumes non-uniform subproblems at runtime. This paper presents six decentralized load distribution strategies. They are incorporated in a runtime support system, and evaluated in the solution of set partitioning(More)
The case of a young woman with still ongoing incest and forced prostitution is presented. The criteria for a dissociative identity disorder (DID) were met. Due to persistent contact to the perpetrator she was repeatedly revictimized. Based on the model of trauma-related dissociation we discuss to what extent she was capable of self-determined decision(More)
We approach the problem of bisectioning the de Bruijn network into two parts of equal size and minimal number of edges connecting the two parts (cross-edges). We introduce a general method that is based on required substrings. A partition is deened by taking as one part all the nodes containing a certain string and as the other part all the other nodes.(More)
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