a novel hierarchical model to locate health care facilities with fuzzy demand solved by harmony search algorithm

In the field of health losses resulting from failure to establish the facilities in a suitable location and the required number, beyond the cost and quality of service will result in an increase in mortality and the spread of diseases. so the facility location models have special importance in this area. in this paper, a successively inclusive hierarchical model for location of health centers in term of the transfer of patients from a lower level to a higher level of health centers has been developed. since determination the exact number of demand for health care in the future is difficult and in order to make the model close to the real conditions of demand uncertainty, a fuzzy programming model based on credibility theory is considered. to evaluate the proposed model, several numerical examples are solved in small size. in order to solve large scale problems, a metaheuristic algorithm based on harmony search algorithm was developed in conjunction with the gams software which indicants the performance of the proposed algorithm.