随机需求下的选址一库存配送系统集成规划模型及算法

Integrated design model and algorithm for location-inventory distribution system under stochastic demand

研究了随机需求条件下由单供应商、候选分拨中心和分销点构成的选址-库存问题,分销点、分拨中心分别基于周期检查(R,s,Q)和连续检查(s,S)库存控制策略．综合考虑库存成本、运输成本和设施成本之间的均衡关系,建立了二级库存与无能力约束选址集成规划模型．给出了适合求解实际规模问题的拉格朗日松弛算法,提出了求解子问题的有效启发式方法,改进了次梯度优化方法．通过仿真试验验证了模型的正确性和算法的有效性．最后讨论了相对于传统规划方法,需求方差、服务水平、持有成本、提前期等关键库存控制参数对系统运营成本节约的影响规律．

The location-inventory distribution system design problem involving one supplier, candidate distribution centers and multiple retailers under stochastic demand is studied in this paper. Retailers adopt periodic review （R, s, Q） inventory policy, while distribution centers adopt continuous review （s, S） inventory policy. Considering the trade-off between inventory cost, shipping cost and facility location cost, the integrated 2-echelon inventory cost function with incapacitated facility location model is presented. A Lagrangian relaxation solution algorithm for realistic scale problem is then proposed. A number of heuristics are also outlined for solving effectively sub-problems. The sub-gradient method is thus improved. Furthermore, simulations are given to confirm the correctness of the model and the effectiveness of the solution. In comparison with traditional approaches, we discussed the sensitivity of potential cost reduction to the changes of inventory control key parameters such as demand variance, holding cost, lead-time and service level.