Time-salving algorithms for vehicule routing and scheduling problems
In this thesis, we deal with modeling and solving various problems including vehicle routing and scheduling. We propose approximate methods that aim to solve problems qui- ckly and e ciently. Five problems are addressed. The rst one is the Resource-Constrained Project Scheduling Problem (RCPSP) for which a multi-commodity ow approach is intro- duced. We also consider methods dealing with extensions of this problem ( nancial or time constraints). The second one is a two dimensional Orthogonal Packing Problem (2OPP) with the resolution being based on its RCPSP relaxation. The third one is the Stacker Crane Problem (SCP). It is a pickup and delivery problem: goods must be transported from starting points to various destinations with a eet of vehicles. In the SCP, a single one-capacity vehicle is available. We propose original tree based models and algorithms for the preemptive case. The fourth one is a Dial-a-Ride Problem (DARP) with nancial constraints. We solve this problem through an insertion heuristic using a constraint pro- pagation technique. The fth one combines routing problem and two dimensional packing. It is the 2L-CVRP in which items have to be delivered to customers. A GRASP ELS framework is introduced for this problem. Experimental results show the e ectiveness of the proposed methods.