DUAL-ASCENT PROCEDURES FOR MULTICOMMODITY LOCATION-ALLOCATION PROBLEMS WITH BALANCING REQUIREMENTS

The multicommodity location-allocation problem with balancing requirements is related to one of the major logistics issues faced by distribution and transportation firms: the management of the fleet of vehicles over a medium to long-term planning horizon. We present a dual-ascent approach for this formulation which may be used either to obtain a good heuristic solution, or to compare sharp bounds in a branch-and-bound scheme. We present and compare two variants of this approach, and analyze their performances both on a large number of randomly generated problems and on a large-scale application to the strategic/tactical planning of the land operations of an international maritime container shipping firm. Our results demonstrate that a dual-ascent approach is highly effective in this context.