关键词: 物流与供应链管理, 库存模型, 最优化, 易变质品, 需求依赖于服务水平

Abstract: This paper deals with two period inventory optimization problem for perishable items where the demand rate depends on the service-level of the previous replenishment cycle. Two scenarios are considered, namely, (1)the buyer order once and (2)the buyer order several times in the selling period. Two inventory models are proposed respectively by maximizing the average profit. In addition, we prove the existence and uniqueness of the optimal inventory service-level and ordering quantity. Finally, an example is presented and the sensitivity analyses on the parameters are conducted to illustrate the validity and the effectiveness of the proposed models. The results show that, in the first case, when the unit inventory holding cost or deteriorating rate increases, the average profit of the system will decrease. As the deteriorating rate increases, the ordering quantity will also increase. In the second case, when the unit inventory holding cost, the expected service-level of customers or the loss rate of order during the shortage increases, the inventory service-level and the average profit of the system will decrease. Only when the inventory holding cost is extremely small, is order once more profitable, so the buyer will usually choose to order several times to enhance the profit. The results also indicate that, service-level is an important factor that influence the inventory policy, and the enterprise should balance the service-level and profits.

Key words: operational management, inventory model, optimization, perishable items, service-level-dependent demand rate