2012-02-01T00:00:00Z, Dornberger, Rolf, Ernst, Ramona, Frey, Lukas, Hanne, Thomas

2009-06-18T00:00:00Z, Hanne, Thomas, Dornberger, Rolf, Frey, Lukas

In this paper we discuss a real-life problem in rail crew rostering. Specific emphasis is placed on the requirements of advanced approaches in rostering and the usage of optimization-based decision support. The modeling of the rostering problems is discussed including the treatment of constraints, the consideration of preferences, and the formulation of several objective functions. The specific solving method of the problem using an evolutionary algorithm and visualization and navigation tools for decision support are sketched briefly and some preliminary results are shown. Finally, some conclusions are presented.

2010-09-27T00:00:00Z, Dornberger, Rolf, Hanne, Thomas, Frey, Lukas

An optimization framework combines various methods, strategies, and programming interfaces on a robust software platform. Its development requires knowledge from application areas, and about optimization methods, as well as from software engineering. Different persons provide diverse know-how about modeling and simulating engineering and/or business problems, about search and optimization methods, and about new software trends to implement them into software. This paper describes the approach how an optimization framework based on evolutionary algorithms and other methods is developed in subsequent projects with application engineers and software developers cooperatively working together guaranteeing a sophisticated knowledge transfer. Therefore, particular knowledge management aspects are emphasized. As result, the optimization platform OpenOpal and the ideas behind its software architecture, supporting the know-how transfer, are presented. In order to continuously improve this optimization framework it is transferred into an open-source software initiative. The objective is to broaden the user group by increasing the number of knowledge contributors both from academia - integrating and testing newly developed optimization methods - and from various engineering areas - providing real-world problems to be solved.

2008-06-01T00:00:00Z, Dornberger, Rolf, Hanne, Thomas, Frey, Lukas

2009-06-28T00:00:00Z, Frey, Lukas, Hanne, Thomas, Dornberger, Rolf

The creation of staff rosters for emergency shifts for doctors is a complex task. To construct good rosters, many restrictions (e.g. holydays and workload) have to be taken into account. These restrictions have been mathematically specified for a concrete case in order to solve the problem afterwards with a straightforward genetic algorithm. Thereby the main focus lays on two different mutation methods and the combination of them. The results of this procedure will be discussed in this work.