Hub location and the design of capacitated intermodal hub networks with different service types

In this thesis, we study hub location and hub network design problems considering different transportation modes and different types of vehicles to serve different types of services. We propose three different problems in this regard. The objective of the first problem is to minimize total costs while providing predetermined service levels, the objective of the second problem is to maximize total profits while determining the service levels to be provided between origin-destination pairs, and the objective of the third problem is to maximize total demand of VIP service to be accepted considering a predetermined budget. All of the problems determine the location of hubs, the allocation of demand nodes to hubs, which hub links to establish, and how many vehicles of which type to operate on hub links to route the demand for different service types between given origin-destination pairs. For each problem, a mixed integer mathematical model is developed and different solution methods are proposed. Turkish network data set and the commercial solver CPLEX are used to solve the mathematical models and test the proposed heuristic methods. The values of the problem parameters on the Turkish network data set are determined based on the interviews made with the three largest cargo companies operating in Turkey. The results obtained by using the proposed heuristic methods are compared with the optimal solutions. In addition, a statistical analysis is conducted to observe the effects of changes in various problem parameters on the proposed heuristics.