在本研究中，我們建立一個與存貨相關的需求的退化性存貨模型，其中我們也將保存技術成本作為決策變數。本模式之目標為求得最佳的訂購及技術投資策略使得最大化利潤總額單位時間。對於任何保存技術的成本，我們首先證明了最佳的訂購策略不僅存在而且是唯一。緊接著，我們也將證明單位時間的利潤為保存技術成本的嚴格凹函數。最後，我們利用一些數值例子來說明模型的應用以及針對參數進行敏感性分析。

  In this paper, we formulate a deteriorating inventory model with stock dependent demand by allowing preservation technology cost as a decision variable in conjunction with replacement policy. The objective is to find the optimal replenishment and preservation technology investment strategies while maximizing the total profit per unit time. For any given preservation technology cost, we first prove that the optimal replenishment schedule not only exists but is unique. Next, we show that the total profit per unit time is a concave function of preservation technology cost when the replenishment schedule is given. We then provide a simple algorithm to find the optimal preservation technology cost and replenishment schedule for the proposed model.Finally, we use some numerical examples to illustrate the model.

Content
Chinese abstract………………………………………………………i
English abstract ………………………………………………………ii
Contents………………………………………………………………iv
Lists of Figures ……………………………………………………v
Lists of Tables ………………………………………………………vi
Notations and assumptions …………………………………………vii
1 Introduction …………………………………………………………1
2 Model formulation……………………………………………………4
3 Optimal strategies and numerical examples …………………………15
Figure 1………………………………………………………………16
Figure 2………………………………………………………………16
Figure 3………………………………………………………………17
4 Concluding remarks …………………………………………………22
References……………………………………………………………23

Lists of Figures
Graphical Representation of Inventory System…………………………4

Lists of Tables
Table 1…………………………………………………………………18
Table 2…………………………………………………………………19

References
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