The Reliable Hierarchical Location-allocation Model under Heterogeneous Probabilistic Disruptions

This paper presents a novel reliable hierarchical location-allocation model where facilities are subject to the risk of disruptions. Based on the relationship between various levels of system, a multi-level multi-flow hierarchy is considered. The heterogeneous probabilistic disruptions are investigated in which the constructed facilities have different site-dependent and independent failure rates. In the occurrence of facility disruptions, to achieve system reliability, the mitigation operation is considered in such a way as to reassign the demand nodes to other operational facilities that can provide services. The problem is modeled from both cost and risk perspectives such that the fixed installation cost as well as the expected costs in normal disruption-free and disruptive conditions are minimized. A Benders decomposition algorithm is developed which seeks to find exact solution of the proposed model. Two efficient accelerating techniques including valid inequalities and knapsack inequalities are also proposed to expedite the convergence of solution procedure. The numerical results illustrate the applicability of the proposed model as well as the efficiency of the designed solution procedure.