總結，本文主要是探討非即時退化性物品並且放寬期末存貨條件的存貨系統，第二章是假設需求率與存貨水準有關，允許缺貨且部分欠撥，欠撥率為固定；第三章則是考慮需求率為時間的指數遞減函數，不允許缺貨。兩章的模型都以使得單位時間總利潤有最大值為目標，然後利用數理方法來求得最適解，並舉範例說明求解過程且對主要參數做敏感度分析。最後，第四章提出本文的結論及未來的研究方向。 Deteriorating items in the nature can be divided into "instantaneous deterioration" and "non-instantaneous deterioration". Instantaneous deteriorating is the item purchased immediately began to degenerate and can’t be retain the original quality. Non-instantaneous deterioration is not immediately degraded after the purchase and it still can maintain the original quality for some time then began to degenerate. This type of item is referred to as "non-instantaneous deteriorating items" and it is also the main items of the inventory we discuss in this paper.
The demand rate of item is changing. Consumers usually attracted by the large quantities of goods on shelves and stimulate purchase intention. And some items are due to short life cycle or homogeneous lead the demand rate of some items decrease rapidly. For example, 3C products , therefore, assuming the demand rate is fixed consistent does not meet current various market environment.
On the other hand, inventory could be the backlog of capital. Inventory models discussed previously ware that sell out of goods then reorder another lots. But for non-instantaneous deteriorating items, before selling out of goods we sell the goods of a lower price then reorder another lots. For retailers, it may be more beneficial for them. Therefore, in this paper, we relax the terminal condition of zero of inventory level at the end of cycle. Then we consider there are still some goods at the end of cycle sold with a lower price and allow shortages, backlogging in the model.
Summary, this paper is to explore the non-instantaneous deteriorating items and relax the terminal condition of the inventory system. In Chapter 2 we assume a demand rate and inventory levels related and we allow the shortages and the partial backorder, backorder rate is fixed. In Chapter 3 we consider the demand rate is a decreasing exponential function of time and don’t allow out of stock. Two chapters of the models in order to achieve the maximum total profit per unit time as the goal, and then use mathematical methods to get the optimal solution. Then we example illustrates both the value and sensitivity analysis of parameters and show the steps of solution. Finally, concluding remarks are made in Chapter 4 and future research directions are proposed.
