CAPACITY SELECTION FOR HUBS AND HUB LINKS IN HUB LOCATION PROBLEMS OVER INCOMPLETE HUB NETWORKS

Hub location problems occur mainly in transportation and telecommunications networks. A hub is a transfer point at which either traffic from several origins is aggregated and forwarded to another hub, or disaggregated into several streams that are forwarded to their destinations. The hub location problem deals with finding the location of hub facilities and allocating the demand nodes to these hub facilities for effective routing of the demand between any origin-destination pair. In the extensive literature, it has widely been assumed that the subgraph induced by the hub nodes is complete. In this research, we provide a variants of the existing hub location problems, under the incomplete hub network design. In addition, a hub network with capacity constraints on the hubs and hub links, which connect hubs to each other, is considered. These capacities are multilevel capacities, so hubs and hub links should take a capacity among a set of capacities. In real world examples the costs of establishing hubs and hub links are expensive. Thus, considering which hub and hub link should be established and which capacity is appropriate, are serious matter in the decision making process. Within this context, the single allocation incomplete hub network design with multilevel capacities of hub and hub link is defined, and mathematical formulations for these problems is introduced. Its computational results are compared with single-level capacity problems and complete hub network design problem. Computational analyses with these formulations are presented on the various instances of the CAB data set.