臺灣博碩士論文加值系統

許多產品在儲存的過程中，會因為蒸發、衰退、過期以及其它原因而不能用，因此，在討論產品的存貨模式時，退化的情況必須加以考慮。過去，大部份討論退化性存貨的文獻，不是考慮固定的退化率，就是只探討特定的需求率函數。其實，產品退化的情況會隨時間而變動，而且，特定的需求率函數並不能涵蓋一切需求的情況。
基於上述理由，本研究建構三個有關退化性產品的存貨模式。首先，在有限的計劃期間內，考慮產品具有線性的退化率，需求率為任一已知的時間函數，允許部份缺貨待補，且服務水準為固定的存貨模式。雖然，此模式很難直接求解，但是，在有限的計劃期間之下，我們推導出其對應之訂購次數的上限，對於求解很有幫助。依此，並透過求解的程序，可以求得最佳的訂購次數以及服務水準。
另外，許多產品（如：IC晶片、流行性商品、乾電池、處方藥等）的壽命都符合韋伯分配（Weibull distribution），因此，另外兩個模式均探討產品壽命服從韋伯分配的存貨模式。其一，是針對新產品且需求率為時間的斜坡型（Ramp type）函數之存貨模式來探討，此模式可獲得唯一的最佳解，且此最佳解與需求率無關。其二，則將需求率推廣到任一已知的時間函數。雖然，此模式無法獲得確定的求解式子，但是，模式中分別針對需求率隨時間遞減以及隨時間遞增的情境，推導出保證有唯一最佳解的充分條件，可提供判斷是否有最佳解的參考。
最後，針對每一個模式所適用的不同情境，分別以實例來說明求解的過程。而且，根據實例所做的敏感度分析，更可提供企業界管理存貨的參考。

Most products will lose their use due to steam, decay, out of date, and many other reasons while they are stored. Thus, their rate of deterioration must be taken into account while analyzing the EOQ model. In the past, many articles have dealt with the deteriorating problem, but either assumed constant deterioration rate or only considered the special demand function. In fact, the rate of deterioration varies over time and special demand rate function cannot cover all of the demand situations.
So, the research developed three inventory models of deteriorating products. First of all, we explored the inventory replenishment policies for the cases with time-varying demand, linearly increasing deterioration rate, partial backordering, constant service level, and equal replenishment intervals over a fixed planning horizon. Since it is difficult to solve the problem directly, we derived the upper bound of replenishment number for a specific planning horizon, and found the solution of service level under a given number of replenishment. Afterwards, the optimal solutions were determined.
Second, because the lifetimes of most products, such as integrated circuit, fashion industry, dry batteries and drugs could be expressed in terms of Weibull distribution. Therefore, the other two inventory models focused on the Weibull distribution deterioration. One of them represents the inventory model of new products with ramp type function of time. In this model, we obtained the only one optimal solution and the solution is independent with demand function. The other one, we proposed a revised EOQ model in which the demand rate is a continuous function of time. This model allowed partial backorder, constant service level, and equal replenishment intervals over a fixed planning horizon. We derived the sufficient condition to ensure that there exists only one optimal solution in the EOQ model. Since it was difficult to derive an explicit formula of optimal solution, a solution procedure was presented to solve the numerical examples.
Finally, we also conducted the sensitivity analyses to derive management implications.

封面
目錄
圖表目錄
第一章 緒論
1.1 研究動機與目的
1.2 研究流程
1.3 研究內容
第二章 文獻探討
第三章 產品據有線性退化率的存貨模式
3.1 基本假設與符號
3.2 模式的推導
3.3 模式的求解過程
3.4 實例分析
3.5 敏感度分析以及管理上的涵意
第四章 產品具有韋伯退化率以及斜坡型需求率存貨模式
4.1 基本假設與符號
4.2 模式的推導
4.3 實例分析
4.4 敏感度分析以及管理上的涵意
第五章 產品具有韋伯退化率的存貨模式
5.1 基本假設與符號
5.2 模式的推導
5.3 模式的求解過程
5.3 實例分析
5.4 敏感度分析以及管理上的涵意
第六章 結論
6.1 結論
6.2 未來研究方向
參考文獻
附錄一
附錄二
附錄三
附錄四

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