Heuristics for a periodic-review policy in a two-echelon inventory problem with seasonal demand

摘要

This paper proposes heuristic methods to determine an ordering policy with a minimum inventory cost while satisfying the expected service level constraint in a divergent two-echelon inventory system. A periodic-review base-stock policy with an echelon stock concept was applied at all locations. Seasonal demand with a short cycle was considered at the level of the retailers. A two-phase heuristic method was then proposed to reduce the computational time required to determine a proper policy compared to the mixed-integer programming models. The first-phase algorithm was used to determine the initial ordering policy for each location, while the second phase algorithm was used to determine the safety stock. Both algorithms could find solutions that are as good as the solutions from the mixed-integer programming models in testing instances but they substantially reduced the computational time. The solutions were tested with other instances having a 10,000-period horizon, where the average loss was within the expected service level and the number of periods with an unsatisfied expected service level was less than 1% of the planning horizon.