multi follower bi-level programming

The decentralized decision-making structure in the design of crisis emergency warehouse network challenges the use of classical optimization models. The aim of this paper is to develop a new multi-follower bi-level optimization model for the emergency warehouse location-allocation problem in terms of national and regional levels. This type of modeling is suitable for countries whose crisis warehouse network design is decentralized. The parameters of the models are based on real data in Iran. Due to the high complexity of the solution, a co-evolutionary approach based on innovative allocation methods and genetic algorithms has been developed to solve the problems with different sizes. The solution structure is designed to be flexible and can be adjusted based on the number of followers and their authority. Finally, an analysis has been done about the change in the number of decision makers and their power to absorb facilities on the objective functions of the bi-level model.