In this paper we consider the location of stops along the edges of an already existing public transportation network. This can be the introduction of bus stops along some given bus routes, or of railway stations along the tracks in a railway network.The positive effect of new stops is given by the better access of the potential customers to public transportation, while the travel time increases due to the additional stopping activities of the trains. The latter leads to a negative effect for the customers. The goal is to cover all given demand points with a minimal amount of additional traveling time, where covering may be defined with respect to an arbitrary norm or gauge. This problem is NP-hard, even in the special case of Euclidean distances. In this paper, we derive a finite candidate set leading to a discrete set covering problem. Moreover, we identify network structures in which the coefficient matrix of the resulting set covering problem is totally unimodular, such that the problem can be solved efficiently in this case. Extensions of the problem are also discussed.
The constraints addressed in decision making during product desicp. process planning and producticn planning determine the admissible solution space for the manufacture of products. The solution space determines largely the costs that are incurred in the production precess. In order to be able to make economically sound decisions, costing data support must be integrated into the decision making processes. Regarding product design, the designer must be supplied with transparent costing data, that is ready for direct application. In this paper a functional architecture for costing data suppori during product design, as well as a corresponding data structure are presented.
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