傳統的經濟訂購量(EOQ)模式中，有兩個很重要的基本假設，其一為消費者所訂購 的貨品皆為良好無瑕疵的產品；其二為消費者在收到貨品的同時必須馬上繳交貨款。 然而，在現實的交易市場中，消費者購買到的貨品有部份是品質有瑕疵的狀況是很常 見的；此外，供應商為刺激買氣，鼓勵消費者，往往會提供允許延遲付款的優惠。因 此，本研究計畫將針對部份貨品品質有瑕疵及供應商允許延遲付款這兩項議題，探討 零售商的經濟訂購模式。為確認銷售出去的貨品品質無虞，本研究計畫假設零售商針 對每件貨品進行檢驗，品質無虞的貨品以一般的市場價格銷售；品質有瑕疵的貨品以 較低的價格提供給次級市場的消費者。本研究計畫分為兩大部分。第一部份：假設檢 驗結果完全正確，探討在供應商提供允許延遲付款的優惠下，零售商該如何擬定其訂 貨策略，才能使得每年的總利潤達到最大。針對上述情況，本研究計畫構建一數學模 式，藉由模式的求解來決定零售商的最佳訂購數量、訂購週期及總利潤；接著，引用 數值範例驗證模式的可行性，並且透過敏感度分析說明最佳訂購策略在管理上的運用 及意涵。第二部份：針對檢驗結果的正確性作討論。檢驗結果有三種狀況: 檢驗正確、 將品質無虞的貨品誤判為品質有瑕疵而以較低的價格提供給次級市場的消費者，以及 將品質有瑕疵的貨品誤判為品質無虞而以一般的市場價格銷售；後兩者的誤判狀況發 生時都會對零售商產生損失。根據上述情況及供應商提供允許延遲付款的優惠下，本 研究計畫構建一數學模式，藉由模式的求解，提出使零售商每年總利潤達到最大的最 佳訂購策略。接著，利用數值範例和敏感度分析來探討檢驗錯誤對最佳訂購數量、訂 購週期及總利潤的影響，同時說明訂購策略在管理上的運用及意涵。最後，就這兩個 模式的最佳解進行比較與分析。 In the traditional economic order quantity (EOQ) model, there are two important assumptions. One is that all items provided by the supplier are perfect quality items. Another is that the consumer must pay for the items received immediately. However, in practices, it is a common situation that the consumer receives some defective items from a lot. In addition, the supplier may offer a permissible delay in payments to the customer in order to stimulate more sales. This project will study EOQ models for the retailer under some defective items and permissible delay in payments. In this project, we assume that all items must be screen by retailer to ensure the items sold are perfect quality. The perfect quality items are sold in the generally market. The defective items are sold in the secondary market at a lower price. There are two scenarios in this project. The first scenario: We assume that all defective items from a lot can be screened out through 100% inspection. Based on the previous situations, this project will establish a new mathematical model to find the optimal ordering policy for the retailer to obtain its maximum profit when the supplier offers a permissible delay in payments. The proposed model is illustrated through numerical examples and sensitivity analysis is reported. The second scenario: The correctness of screening will be considered. There are three cases for the screening. 1. The result of screening is correct. 2. A good item is classified as defective and is sold in the secondary market at a lower price. 3. A defective item is classified as good and is sold in the generally market. Cases 2 and 3 will reduce the profit of retailer. To reflect the above circumstances and the permissible delay in payments offered by supplier, we will develop a new mathematical model to determine the optimal ordering policy that maximizes the profit of retailer. Next, numerical examples are provided to illustrate the solution procedure. Sensitivity analysis is carried out to discuss the influence of inspection errors on the optimal solution and to investigate critical parameters. Finally, we will make comparisons between the optimal solution of the first scenario and that of the second scenario.