The elastic generalized assignment problem (eGAP) is a natural extension of the generalized assignment problem (GAP) where the capacities are not fixed but can be adjusted which is expressed by continuous variables. These variables might be un-bounded or restricted by a lower or upper bound,...

The elastic generalized assignment problem (eGAP) is a natural extension of the generalized assignment problem (GAP) where the capacities are not any longer fixed but can be adjusted which is expressed by continuous variables. These variables might be unbounded or restricted by a lower or upper...

Resource-constrained project scheduling under a net present value objective attracts growing interest. Because this is an NP-hard problem, it is unlikely that optimum solutions can be computed for large instances. Thus, heuristics have become a popular research field. Up to now, however, tight...

This paper introduces a new general framework for genetic algorithms to solve a broad range of optimization problems. When designing a genetic algorithm, there may be several alternatives for a component such as crossover, mutation or decoding procedure, and it may be difficult to determine the...

The sales force deployment problem is considered which arises in many selling organizations. As a solution a novel mixed-integer formulation is introduced which is specifically characterized by an infinite number of variables. A column generation approach is proposed to obtain upper and lower...

Sales force management decisions belong to the major issues considered in marketing research. Among others, the alignment of sales territories has been one of the main field of work for years. Recent results have reported a strong impact of the alignment of sales territories on profit, and,...

In der vorliegenden Untersuchung wird die operative Entscheidung über Eigenfertigung und Fremdbezug betrachtet. Exemplarisch wird dargelegt, dass klassische Entscheidungshilfen unwirtschaftliche Ergebnisse hervorbringen. Die qualitative und quantitative Fehlspezifikation der Fremdbezugsprodukte...

On a very abstract level, an information system consists of a set of system elements which communicate with each other. Communication is an unproductive operation, so the time needed to communicate data should be kept as short as possible and, to put it in monetary terms, the opportunity costs...

The Capacitated Facility Location Problem (CFLP) is a well-known combinatorial optimization problem with applications in distribution and production planning. A variety of lower bounds based on Lagrangean relaxation and subgradient optimization has been proposed for this problem. However, in...

The "Capacitated lot sizing problem with setup carry-over" is based ort the well known "Capacitated lot sizing problem" and incorporates the possibility of preserving a setup-state from a period to the following. Sox and Gao [2] decompose their formulation of the first one (GCLP1) by Lagrangian...