Günter Kiechle

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In this paper, heuristic solution techniques for the multi-objective orienteering problem are developed. The motivation stems from the problem of planning individual tourist routes in a city. Each point of interest in a city provides different benefits for different categories (e.g., culture, shopping). Each tourist has different preferences for the(More)
In this paper a model and several solution procedures for a novel type of vehicle routing problems where time windows for the pickup of perishable goods depend on the dispatching policy used in the solution process are presented. This problem is referred to as Vehicle Routing Problem with multiple interdependent time windows (VRPmiTW) and is motivated by a(More)
In this paper we first provide a thorough performance comparison of the three main Ant Colony Optimization (ACO) paradigms for the Vehicle Routing Problem (VRP), namely the Rank based Ant System, the Max-Min Ant System and the Ant Colony System. Based on the results of this comparison we then implement a parallelization strategy to increase computational(More)
For regular patient transportation and emergency transportation with ambulance vehicles a dynamic dial-a-ride (DARP) problem has to be solved. We analyze two scheduling strategies for the regular dial-a-ride orders in order to minimize routing costs and to maximize transportation quality. Furthermore, we review practical requirements and suggest a(More)
Dispatching ambulances is a demanding and stressful task for dispatchers. The aim of this work was to investigate if and to what extent the dispatch operation of the Red Cross Salzburg (RCS) can be optimized with a computerized system. The basic problem of a dynamic multi-vehicle Dial-a-Ride Problem (DARP) with time windows was enhanced according to the(More)
Dispatching ambulances is a demanding and stressful task for dispatchers. This is especially true in case of mass-casualty incidents. Therefore, the aim of this work was to investigate if and to what extent the dispatch operation of the Red Cross Salzburg can be optimized on such occasions with a computerized system. The basic problem of a dynamic(More)
39 Vehicle Routing Problems (VRPs) are a widely investigated class of problems in combinatorial optimisation, and include many transportation tasks (eg parcel services). In general, a VRP consists of a set of customers that must be served via a fleet of vehicles, each of which leaves from and returns to a central depot. The type of VRP determines whether(More)
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