The Hierarchical Hub Covering Problem with Innovative Allocation Procedure by Covering Radiuses

Hub location problems deal with locating hub facilities in one level of services or one type of facility, but some systems are performed by several types of facilities. So this paper attempts to study the single allocation hierarchical hub covering facility location problem over complete network linking in the first level, which is consisted of hub facilities known as central hubs. In addition, the study proposes a mixed integer programming formulation and finds the location of the hubs in the second level and central hubs in the first level so that the non-hub and hub nodes allocate to the opening hub and central hub nodes. Therefore, the travel time between any origin destination pair is within a given time bound. The current study presents an innovative method for computing the values of radiuses in order to improve computational time of the model and to test the performance of the mentioned heuristic method on the CAB data set and on the Turkish network. The helpful results were obtained including: the severe reduction in the time of solution, the rational distribution of the centers for presenting results, equality (Justice) and appropriate accessibility consistent with the different levels of servicing. A computational experience was applied to Iranian hub airports location.