Facility LocationM odel for Multi-levelReturned Logistics and ItsAlgorithm

A facility locationmodel formulti-level returned logisticswas proposed to study the issues of collection, preprocessing and remanufacture of end-of-life products. Thismodel is amixed integer linear program (MILP), and is solved with a branch and bound (B&B) algorithm. To make B&B faster in convergence and less in calculation, a genetic algorithm is used to obtain a reasonably good resolution at the beginning ofB&B. The objective value corresponding to the resolution is taken as the upperbound ofB&B to prune a large number of branches from the searching tree. An example was presented to verify the effectiveness and feasibility of the proposedmethod.