A Hierarchical Covering Location Model with a Multi Period under Uncertainty

In this study, the model in the framework of hierarchical covering location by taking a dynamic approach (the radius of coverage and the amount of demand in different periods dynamically) in the fuzzy provide and studied. Location and allocation model for hospitals and facilities that includs rescue helicopter and ambulance to the demand, to establish and cover of demand that they are in the radius of coverage, provided, and also considered the possibility of being busy facility. The status of Subspecialty hospital, hospital and clinic locate and in different periods of time are fixed. Fuzzy concept has been used to draw closer to reality. Site of the service facilities, including ambulances and helicopters are variable in different periods. Also in models for this movement is considered cost. Services machines and hospitals and clinics have limited capacity. Given the fact that the goal is just to validate the model, numerical data is used. The method of solving this problem is using the numerical example of the GAMs software definitive method, and for larger scales, the ABC algorithm and ICA are used. To validate the proposed model, it compares it with Bashiri et al. Model model. The numerical results show the optimal efficiency of the proposed solution method and the problem model.