在日常生活中，存貨問題為各行各業中最基本，也是最重要的問題之一，因此，許多企業都希望透過有效的方法，擬定一個最適的存貨策略。近年來，產品退化的現象常被提出討論，在傳統的存貨問題中，都假設產品的品質不會隨著時間的流逝而有所變化，但在實際情況中並非如此，存貨物品的退化是很正常的現象。此外，當產品的供應不能滿足顧客的需求時，便會發生缺貨；當缺貨發生時，只有部份的消費者願意等候欠撥，而另一部份的消費者因不願等候而轉向其他競爭廠商購買。因此在考量最大的經濟利益下，擬定一個適當的訂購策略，是很重要的。 本論文係研究具非瞬間退化性的單一產品，需求率與存貨水準有關且允許缺貨的存貨模式，全文包含兩個存貨模式，首先，第二章討論固定欠撥率的存貨模式，其目的在找出沒有短缺的存貨期間及訂購週期長度，以使單位時間有最小的總相關成本。對所建立的模式，我們以傳統的最佳化原理證明最適解存在，接著，由於模式的複雜性，透過電腦數學軟體Mathematica4.1協助搜尋最適解。第三章則延續第二章的討論，假設欠撥率服從一隨機分配，並在文中加入數量折扣的考量，其目的在找出最適的訂購策略。 In real life, inventory is one of the most important and basic problem in every walk of life. Therefore, many enterprises want to make the optimal inventory strategy through effective methods. In recent years, the situation of .products deterioration has also been proposed and discussed. In traditional inventory problems, quality is not change with wait time. But in realistic circumstances, products deterioration is normal situation. Besides, if products can not satisfy customers, the shortages would occur. when the shortages occur, some customers are willing to wait for backorder and others would turn to buy from other sellers. Hence, it is very important to make the optimal strategy in order to consider the best economic benefits. This study consider some inventory models for non-instantaneous deteriorating items with demand rate dependent inventory level and partial backlogging. This article involves two models. First, we discuss the model with fixed backlogging rate. The objective is to find the length of time in which the inventory is no shortage and the length of order cycle such that the minimum total relevant inventory cost per unit time of inventory system. In this model, we can prove that the optimal solution is existence and uniqueness. Because the model is complex, we use software Mathematica4.1 to find the optimal solution. At last we discuss the model with backlogging rate of random distribution and consider quantity discount in this model. The objective is to find the optimal order strategy.
