企業要在快速且激烈的市場競爭，必須建置一個自身參與的供應鏈並且應用及時化(Just-in-time)生產的方法去提升採購及存貨管理的績效。在建置供應鏈長期合作關係的過程中，能提供較短的前置時間交期及良好品質的供應商在爭取客戶的訂單及滿意度是較具競爭力的；此外，能提供優良服務的供應商一旦取得來自多個客戶的訂單，如何妥善安排供應滿足需求是管理者的重要課題，而適量的存貨準備一直是企業調節供需的重要手段。因此，在存貨及交貨政策方面，買賣雙方必須考慮整體利益來做出最適決策以達到總相關成本最小化。
本研究旨在針對前置時間內需求量服從常態分配的假設下，提出兩個單一供應商及多買家的整合性存貨模式使得買方與賣方總存貨成本最小化，並求得最適存貨政策。在第一個模式中，我們假設製程是完美的並且視前置時間為可控制變數，而前置時間可以在付出額外的趕工成本下縮短，並提出一個求解演算法。在第二個模式中，我們放寬完美製程的假設去考慮製程不良的機率，並加入品質改善投資選項，同時提供一個求解演算法。此外，提出不同買家數量的數值範例來加以說明。

Competing in rapid and violent marketplace, firms construct their own supply chain system and apply the means of Just-in-time (JIT) production to enhance their purchasing and inventory management performance. In the creation of long-term partnership in supply chain, the vendor who can provide consistent quality and short delivery lead time is easily to gain customers’ satisfaction and order. Furthermore, once a vendor can provide good service to acquire order from multiple buyer, the suitable decision of inventory and delivery policy should be considered by both parties from a whole benefits for minimizing the total relevant cost in the integrated inventory model.
This paper develops two single-vendor multiple-buyer integrated inventory models for minimizing the total relevant annual costs incurred by the vendor and the buyers. The objective is to determine the optimal inventory policies while the probability distribution of lead time demand is normal. First we assume that the process is perfect and lead time is controllable and can be shortened at an extra crashing cost, an algorithm is developed to find the optimal solution. Then, we relax the assumption of perfect process to consider the probability of process being out-of-control, and the option of investing in process quality improvement is included, an algorithm is developed to find the optimal solution. Finally, numerical examples for deferent number of buyer are given to illustrate the results.

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