Dual Sourcing from Suppliers with Different Leadtimes, Yields and Costs
We study a single-item, periodic-review dual sourcing model in which a buyer can place orders from two suppliers named Supplier Ⅰ and Ⅱ with different leadtimes, yields and costs.We assume that Supplier Ⅰ has no leadtime while Supplier Ⅱ has one-period leadtime. The replenishment yield from Supplier Ⅰ is uncertain while the replenishment from Supplier Ⅱ is certain. Moreover, the variable costs of these two suppliers may be different. Demands in consecutive periods are independent random variables. Stockouts are fully backlogged. Our problem is to characterize the optimal dynamic policy that simultaneously determines the order quantities from two suppliers to minimize the total discounted cost. We show that the optimal replenishment policy from Supplier Ⅰ is of a threshold type, I.e., an order is placed if and only if the initial inventory is below a threshold. And the optimal replenishment policy from Supplier Ⅱ is of an order-up-to level type, but the level depends on the initial inventory. To understand the implication of dual sourcing and random yields, we compare our model with two existing models in the literature: one includes dual sourcing but without uncertain yield; the other includes uncertain yields but only one supply source. Comparing with the first model, we prove that the threshold of replenishment in our model is higher in the multiperiod case. In addition, we demonstrate that the impact of suppliers variable costs cannot dominate the decision of the sourcing choice when the yield is uncertain. Next, by comparison with the second model, we find that the dual-sourcing strategy may induce the buyer to maintain higher on-hand stock for enhancing demand fulfillment and is significantly cost-efficient when the inventory is insufficient.
国际会议
2007 International Conference on Manufacturing & Service Operations Management(2007制造与服务运作管理国际学术会议)
北京
英文
2007-06-18（万方平台首次上网日期，不代表论文的发表时间）