Roberto D. Galvão

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A 2-level hierarchical extension of the maximal covering location problem is considered and an e0ective method for its solution developed. A combined Lagrangean–surrogate (L–S) relaxation is de6ned which reduces to a 0–1 knapsack problem. Tests were carried out using a subgradient-based heuristic incorporating the L–S relaxation, with the resulting knapsack(More)
We compare heuristics based on Lagrangean and surrogate relaxations of the Maximal Covering Location Problem (MCLP). The Lagrangean relaxation of MCLP used in this paper has the integrality property and the surrogate relaxed problem we solve is the LP relaxation of the original 0ÿ1 knapsack problem. The heuristics were compared using 331 test problems(More)
We present a 3-level hierarchical model for the location of maternal and perinatal health care facilities in Rio de Janeiro. Relaxations and heuristics are developed for this model and computational results are given for problems available in the literature, for networks ranging from 10 to 400 vertices. The quality of the solutions produced by the(More)
The maximal expected covering location problem (MEXCLP) and its adjusted counterpart (AMEXCLP) compute expected coverage arising only from unqueued calls, whereas the interactive use of the hypercube queueing model (HQM) considers both unqueued and queued calls in this computation. In this note we show that the three models are not strictly comparable(More)
Recent work on the location of perinatal facilities in the municipality of Rio de Janeiro resulted in the development of an uncapacitated, three-level hierarchical model. An important issue that arose during the course of the research was the need to include some form of capacity constraints into the model, especially in the higher, resource intensive level(More)
Capacity effects are investigated, particularly as regards congestion of facilities with immobile (or fixed) servers. A review is given of research to date in this area, together with some related work. First, general implications of facility capacities being capacitated are discussed with regard to assignment of users to facilities, time (or distance)(More)