Synchronized Planning of Interdependent Resources in Transport Logistics

• Applicant: Professor Dr. Stefan Irnich
• Subject Area: Accounting and Finance
• Term: from 2014 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 255380381

Based on own previous work, the objective of the planned project is to contribute to research in the field of modelling and exact and heuristic solution of vehicle routing problems with multiple synchronization constraints (VRPMSs).In the basic problem of vehicle routing, a set of transport requests is given. A transport request consists in delivering a certain amount of a good to a specified customer (location). To this end, a set of vehicles with limited loading capacity is available. The problem is to determine a cost-minimal routing plan, that is, to group transport requests into clusters that can be performed by one vehicle each, and to set the sequence of the requests in each cluster, so that the overall travelled distance or the number of necessary vehicles is minimized.VRPMSs differ from other VRPs in that the resources available to fulfil the transport requests, that is, vehicles, drivers and containers, are interdependent, and that their use must be synchronized in several respects: Beside the requirement to decide which resource(s) should perform which request(s), VRPMSs possess synchronization requirements with regard to time, space, and load.VRPs have been scientifically studied for years. One reason for this continued research activity is the mathematical and informational challenge that VRPs pose. Another reason is the considerable practical relevance of vehicle routing. VRPMSs, however, have been largely neglected by science so far. This is mostly due to the fact that a mere synchronization of request fulfilment does not induce interdependencies between resources, whereas multiple synchronization requirements lead to intricate interdependencies that are not easy to handle algorithmically.Applications of VRPMSs can be found in food distribution, home care staff dispatching and multi-modal transport in the less-than-truckload business, parcel delivery services, and city logistics.For solving VRPs, on the one hand, exact methods of discrete optimization are used, on the other hand, heuristics and metaheuristics are applied. The latter do not guarantee finding optimal solutions, but they are used, because problem instances of real-world size can still not be consistently solved exactly in reasonable time. Therefore, the deliveries of the planned project are:- An implementation of a generic heuristic for general VRPMSs- An implementation of an exact algorithm for general VRPMSs- Theoretical, mathematically proven and empirical, statistically validated statements on the performance of the solution procedures for solving different types of VRPMSs

• DFG Programme: Research Grants