--This paper considers a class of cargo ship routing and scheduling problems from industrial and tramp shipping and presents a wide range of benchmark instances that have been created to represent realistic planning problems for various shipping segments. Initial results for the benchmark instances are provided both through exact and heuristic methods. Optimal solutions to smaller problem instances are provided by a commercial mixed-integer programming solver, and high-quality solutions to larger problem instances are provided by a state-of-the-art adaptive large neighborhood search heuristic. The provided benchmark instances, as well as an instance generator, intend to stimulate future development of solution algorithms for this important planning problem, and to provide a basis for modelling and solving various real-life problem extensions that go beyond what is included in the benchmark instances.
This paper puts forward a location-routing problem with time windows (LRPTW) under uncertainty. It has been assumed that demands of customers and travel times are fuzzy variables. A fuzzy chance constrained programming (CCP) model has been designed using credibility theory and a simulation-embedded simulated annealing (SA) algorithm is presented in order to solve the problem. To initialize solutions of SA, a heuristic method based on fuzzy c-means (FCM) clustering with Mahalanobis distance and sweep method has been employed. The numerical experiments which were carried out, clearly attest that the proposed solution approach is both effective and robust in solving problems with up to 100 demand nodes in reasonable times.
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