本研究主要目的為解決當供應商對損耗性商品提供延遲付款之訂購條件時，零售商之最適訂購量。供應商在零售商長期訂購下，希望零售商訂購更多數量，因此願意給予零售商延遲付款優惠，然而零售商並非每一次訂購皆可享有延遲付款的好處，當零售商訂貨數量高於供應商要求的最低訂購條件時，零售商便享有延遲付款優惠，然而當信賴交易期間期滿時，零售商得立即交付帳款；當零售商訂購數量低於供應商給予延遲付款所要求的最低訂購數量時，零售商則無法享受此優惠。當零售商享受延遲交款的優惠時，會有利息收入與機會成本的相關費用，零售商訂購較多數量時，銷售數量會增加，但持有成本也會增加，因此零售商如何訂定最適訂購數量與供應商如何制訂優惠政策為本研究主要探討的問題。

藉由模式建構與範例分析之後，本研究可以提供供應商要給予延遲付款優惠時，找出制訂優惠的數量條件與供應商可接受之信用交易期間長度，在零售商方面，找出零售商願意接受的最短信用交易期間長度，並提出零售商求解方式。經由敏感度分析，探討參數對於模式的影響與供應商在延遲付款下如何去控制零售商訂購量的方法。

The study presents an inventory model for deteriorating items with stock-dependent demand rate under permissible delay in payments depending on the ordering quantity. When the retailer’s ordering quantity is more than or equal to the predetermined quantity set up by the supplier, the retailer can postpone paying the money and increase demand. However, the retailer will increase the opportunity cost, interest income as well as
holding cost. Therefore, how to order the suitable quantity is the main issue for the retailer. The study will talk over how to order the quantity for the retailer in the preferential treatment and how to determine the preferential terms such as the trade credit period and predetermined quantity for the supplier.

After establishing the model and analyzing the example, the study can give information for the retailer and the supplier. If the supplier wants to offer the retailer the preferential treatment, he can set up predetermined quantity and the trade credit period which is an important factor effecting the retailer’s ordering quantity by the study result. Base on the predetermined quantity, the retailer will know what is the minimum trade credit period to accept the preferential treatment. Finally, the study can help the retailer to make decision.

石志強，在延遲付款期限下的損耗性存貨模式。未出版之碩士論文，私立中原大學工業工程學系，桃園縣，民國89年。

黃永富，在允許延後付款情況下之確定性存貨模式的最佳補貨政策。未出版之博士論文，國立台灣科技大學工業管理系，台北市，民國91年。

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