In this paper we develop a network location model that combines the characteristics of ordered median and gradual cover models resulting in the Ordered Gradual Covering Location Problem (OGCLP). The Gradual Cover Location Problem (GCLP) was specifically designed to extend the basic cover objective to capture sensitivity with respect to absolute travel distance. Ordered Median Location problems ...

The facility terminal cover problem is a generalization of the vertex cover problem. The problem is to “cover” the edges of an undirected graph G = (V, E) where each edge e is associated with a non-negative demand de. An edge e = [u, v] is covered if at least one of its endpoint vertices is allocated capacity of at least de. Each vertex v is associated with a non-negative weight wv. The goal is...

The paper addresses a multi-item, multi-plant lot-sizing problem with transfer costs and capacity constraints. The problem is reformulated according to a multi-commodity flow formalism, and decomposed, through Lagrangean relaxation, into a master facility location problem and a slave minimal cost multi-commodity flow problem. The decomposition framework gives rise in a natural way to the design...

This paper describes a study aimed at evaluating the capabilities of simulated annealing in dealing with complex, real-world multi-period location problems raised by school network planning in Portugal. The problems were formulated as mixed-integer linear optimization models. The models allow for facility closure or size reduction besides facility opening and size expansion, with sizes possibly...

The thin-layer Navier-Stokes equations are solved for two complete missile configurations on an IBM 3090-200 vectro-facility supercomputer. The conservation form of the three-dimensional equations, written in generalized coordinates, are finite differenced and solved on a body-fitted curvilinear grid system developed in conjunction with the flowfield solver. The numerical procedure is based on ...

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 rat...