臺灣博碩士論文加值系統

在以往有關存貨理論的文獻中，不論是確定性模式（deterministic model）或機率性模式（probabilistic model），大多將前置時間視為已知且不可控制的常數（uncontrollable constant）或隨機變數，並且也將欠撥率視為已知且不可控制的常數。但是近年來，有不少學者開始對於欠撥率是否真的為不可控制的常數或前置時間是否真的為不可控制的隨機變數產生質疑，進而著手進行在連續性檢查訂購策略下之可控制欠撥率及可控制前置時間的相關研究。在此檢查策略之下，已經有學者進一步去探討欠撥率與缺貨數量、欠撥率與欠撥價格折扣，以及前置時間與訂購量間的互動關係。但是以往的文獻中，雖然已考慮到前置時間的控制，但往往都忽略了缺貨數量與欠撥價格折扣兩者同時對於欠撥率的影響，這樣的訂購策略在實務上來說是很不切實際的。所以，在本文中我們將欠撥價格折扣視為決策變數，並且考慮欠撥率為缺貨數量與欠撥價格折扣的函數，而缺貨數量分別為線性遞減函數與指數遞減函數這兩種情況。而一般實務上，在前置時間內，不同的顧客在其需求上亦會有所差異，所以不能只用一個需求分配來滿足顧客在前置時間內的需求。因此，在本文中我們考慮使用混合分配來描述前置時間的需求量。
本文第二章我們結合Pan和Hsiao（2001）與Ouyang和Chuang（2001）所定義的欠撥率函數，並且提出一個廣義的欠撥率函數，同時應用Wu和Tsai（2001）所提到的混合分配之型式，考慮以混合分配F*=pF1+(1-p)F2，來滿足前置時間顧客的需求量，並且在訂購量、欠撥價格折扣及前置時間為決策變數時，發展出一套演算法以決定最適的訂購策略與最小總成本。第三章我們推廣Ouyang et al.（1999）的模式，在連續性檢查之存貨系統中，可藉由投資資金來縮減訂購成本，同於前一章，我們亦考慮了混合常態與混合分配未知但具有已知的一階與二階動差的情況，並各自在訂購量、訂購成本、欠撥價格折扣和前置時間為決策變數時，發展出演算法來求得最適的訂購策略與最小總成本。最後，第四章為結論，對本文各章所建構的存貨模式做歸納整理，同時提出未來的研究方向。

In most of the literature dealing with inventory problems, either in deterministic model or probabilistic model, lead time is usually viewed as a prescribed constant or a stochastic variable and backorder rate is usually viewed as a prescribed constant, which therefore, is not subject to control. But recently, many authors started to present their studies about a continuous review model in which they consider the controllable backorder rate and the controllable lead time. Besides, many authors discussed the relationship between the backorder rate and the amount of shortages, the backorder rate and the backorder discounts offered by the supplier, and the lead time and the order quantity. But they always ignored that the backorder rate can be affected by the amount of shortages and backorder discounts together. This kind of order policy is not reasonable. So, in this article we try to consider the backorder discounts as a decision variable and consider the backorder rate as a function of the amount of shortages and backorder discounts, where the amount of shortages is a linearly decreasing function or a exponential decreasing function. And in many practical situations, we can not use only a single distribution to describe the customers’ demands of the lead time. So, we consider to use a mixtures of distribution to describe the demand of the lead time.
In Chapter 2, we propose a generalized backorder rate by using the definitions of the backorder rate of Pan and Hsiao(2001) and Ouyang and Chuang(2001) , and apply the form of the distribution of the lead time demand presented by Wu and Tsai(2001). Then we use the mixtures of distribution
F*=pF1+(1-p)F2 to describe the demand of the lead time and discuss the situations when the order quantity, backorder discounts and lead time as decision variables. In Chapter 3, we extend the model of Ouyang and Wu(1999) to consider the continuous review inventory systems, where the ordering cost can be reduced by capital investment. Then we use the mixtures of distribution F*=pF1+(1-p)F2 to describe the demand of the lead time and discuss the situations when the order quantity, ordering cost, backorder discounts and lead time as decision variables. Finally, the conclusion and the future research are also given in chapter 4.

第一章 緒論 …………………………………………………………… 1
1-1 研究動機與目的 ………………………………………………… 1
1-2 文獻探討 ………………………………………………………… 3
1-3 本文研究內容 …………………………………………………… 5
第二章 隨機變數前置時間服從混合型分配在具有欠撥價格折扣下
的混合存貨模式 ……………………………………………… 7
2-1符號說明與假設 ………………………………………………… 7
2-2前置時間需求量服從混合型常態分配之存貨模式 …………… 10
2-2-1決策變數為訂購量、欠撥價格折扣與前置時間，
而欠撥率為缺貨數量與欠撥價格折扣的線性函數
之存貨模式 …………………………………………………………… 16
2-2-2決策變數為訂購量、欠撥價格折扣與前置時間，
而欠撥率為缺貨數量與欠撥價格折扣的指數函數
之存貨模式 …………………………………………………………… 21
2-2-3數值範例 ……………………………………………………… 26
2-3前置時間需求量服從的分配未知之存貨模式 ………………… 27
2-3-1決策變數為訂購量、欠撥價格折扣與前置時間，
而欠撥率為缺貨數量與欠撥價格折扣的線性函數
之存貨模式 …………………………………………………………… 28
2-3-2決策變數為訂購量、欠撥價格折扣與前置時間，
而欠撥率為缺貨數量與欠撥價格折扣的指數函數
之存貨模式 ………………………………………………………… 36
2-3-3數值範例 ……………………………………………………… 42
2-4敏感性分析 ……………………………………………………… 43
第三章 隨機變數前置時間服從混合型分配且縮減訂購成本
的混合存貨模式 ……………………………………………………… 49
3-1符號說明與假設 ………………………………………………… 49
3-2前置時間需求量服從混合型常態分配之存貨模式 …………… 50
3-2-1決策變數為訂購量、訂購成本、欠撥價格折扣
與前置時間，而欠撥率為缺貨數量與欠撥價格折扣的
線性函數之存貨模式 ………………………………………………… 51
3-2-2決策變數為訂購量、訂購成本、欠撥價格折扣
與前置時間，而欠撥率為缺貨數量與欠撥價格折扣的
指數函數之存貨模式 ………………………………………………… 58
3-2-3數值範例 ……………………………………………………… 64
3-3前置時間需求量服從的分配未知之存貨模式 ………………… 65
3-3-1決策變數為訂購量、訂購成本、欠撥價格折扣
與前置時間，而欠撥率為缺貨數量與欠撥價格折扣的
線性函數之存貨模式 ………………………………………………… 66
3-3-2決策變數為訂購量、訂購成本、欠撥價格折扣
與前置時間，而欠撥率為缺貨數量與欠撥價格折扣的
指數函數之存貨模式 ………………………………………………… 74
3-3-3數值範例 …………………………………………………… 81
3-4敏感性分析 ……………………………………………………… 82
第四章 結論 ………………………………………………………… 90
參考文獻 ……………………………………………………………… 95
附錄： ………………………………………………………………… 99

中文部份
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