The hierarchical hub covering problem with an innovative allocation procedure covering radiuses

Hub location problems deal with locating hub facilities at one level of servicesor one type of facility, but some systems are performed by several types of facility. so,this paper attempts to study a single allocation hierarchical hub covering a facility locationproblem over a complete network linking at the rst level, which consists of hub facilitiesknown as central hubs. in addition, the study proposes a mixed integer programmingformulation and nds the location of the hubs at the second level and central hubs atthe rst level, so that the non-hub and hub nodes are allocated to the opening hub andcentral hub nodes. thus, the travel time between any origin destination pair is within agiven time bound. the current study presents an innovative method for computing thevalues of radiuses in order to improve the computational time of the model and to test theperformance of the mentioned heuristic method on the cab data set and on the turkishnetwork. helpful results were obtained, including: severe reduction in the time of solution,rational distribution of the centers for presenting results, equality (justice) and appropriateaccessibility consistent with dierent levels of servicing. a computational experience wasapplied to the iranian hub airport location.