信用交易的存貨模式近幾年來廣泛地被許多學者所討論。對於供應商而言，提供信用交易可以刺激消費和減少貨物的庫存。另一方面，對於零售商而言，藉由信用交易可以降低成本，增加利潤。過去，有關信用交易的文獻，大都假設倉庫容量沒有限制且需求率和售價無關。但在現實生活中，因為資金有限和土地取得不易，致使自有倉庫容量有所限制，因而零售商需要外租倉庫來存放過多的貨品。再者，需求率常會受到售價高低的影響而非固定的常數，當售價高時則需求率會下降；反之則會上升。因此，我們有必要將變動的需求率納入模式中。 本研究的目的是探討不同的信用交易策略分別對倉庫容量有限，以及需求與售價有關這兩個存貨系統的影響。使用現金流量折現法來求得最適的補貨策略及總成本(利潤)的最小(大)淨現值。第二章假設倉庫容量有限，供應商給予零售商一段固定的信用交易期限，並且若零售商於更早的時點付清貨款時，還可以享受現金折扣的優惠。第三章則在需求與售價有關的情況下，供應商提供零售商一個信用交易期限，並且當零售商訂購達到某一數量時還可以享受現金折扣。對所建立的兩個存貨模式，我們分別得到最適解存在且為唯一的條件，並以數值範例說明求解的過程。第四章則為本研究的結論以及未來的研究方向。 Recently, the inventory models under trade credit have been widely studied by many researchers. Offering a credit period will encourage the supplier’s selling and reduce on-hand stock level. On the other hand, the retailer can take advantages of a credit period to reduce cost and increase profit. Most previous models about trade credit assumed that the capacity of the own warehouse is unlimited and demand rate is independent to the retail price. In fact, it is possible for the management to purchase more goods than can be stored in the owned warehouse. When the stock level exceeds the capacity of the own warehouse, a rented warehouse is used. Also, a lower price will induce more sales and profit. Hence, analysis of an inventory system where the demand rate is influenced by selling price is a practical issue. The purpose of this research is to study the effect of different trade credit policies on inventory systems with limited warehouse capacity and price-sensitive demand. The Discount Cash-Flow (DCF) approach is applied to find the optimal replenishment policy and the minimum(maximum) net present value of total cost(profit) over the infinite horizon. In chapter 2, we considered an inventory model with limited warehouse capacity, in which the supplier provides both cash discount and delayed payment to the retailer. That is, supplier provides a cash discount to encourage the retailer to pay for goods quickly; otherwise, the full purchasing price must be paid at the due date of credit period. In chapter 3, we established an inventory model with price-sensitive demand and trade credit, in which the supplier further provides a cash discount to the retailer if the order quantity is greater than or equal to a predetermined quantity. In both chapters, the existence and uniqueness of the optimal solutions are proved and numerical examples are provided to illustrate the proposed models. Finally, we provided the conclusions and future research in Chapter 4.