Abstract
The Vehicle Routing Problem with Time Windows (VRPTW) is an important problem occurring in many logistics systems. The objective of VRPTW is to serve a set of customers within their predefined time windows at minimum cost. Ant Colony System algorithm (ACS) that is capable of searching multiple search areas simultaneously in the solution space is good in diversification. On the other hand, Simulated Annealing algorithm (SA) is a local search technique that has been successfully applied to many NP-hard problems. A hybrid algorithm (IACS-SA) that combines an improved ACS with SA is proposed in this paper. The algorithm has been tested on 56 Solomon benchmark problems. The results show that our IACS-SA is competitive with other meta-heuristic approaches in the literature. The results also indicate that such a hybrid algorithm outperforms the individual heuristic alone.
