Modeling the budget-constrained dynamic uncapacitated facility location-network design problem and solving it via two efficient heuristics: A case study of health care

This paper presents a model for the budget-constrained dynamic (multi-period) uncapacitated facility location-network design problem (DUFLNDP). This problem is concerned with the determination of the optimal locations of facilities and the design of the underlying network simultaneously in which there is a budget constraint on investment for opening the facilities and constructing (activating) links for each time period during the planning horizon. The objective is to minimize the total travel costs for customers and operating costs for facilities and network links. Furthermore, a greedy heuristic and a fix-and-optimize heuristic based on simulated annealing and exact methods (Branch & Bound and cutting methods) are proposed to solve the model. The performance of the proposed algorithms were tested on extensive randomly generated instances and compared with the CPLEX solver. The budget-constrained DU FLNDP has a lot of important applications which as one of them, the accessibility of health care facilities in Illam Province of Iran is investigated. (C) 2012 Elsevier Ltd. All rights reserved.