存貨是企業體極為重要的一部分。存貨管理的基本目標是建立一個存貨控制系統以決定應訂購或生產多少數量和何時請購或生產才能使存貨總相關成本達最小化。以往有關前置時間的研究文獻，無論是確定性模型或是機率性模型，大多將前置時間視為已知且不可控制的常數或隨機變數，近年來已有很多學者對不可控制的前置時間開始產生質疑，進而著手探討連續性檢查訂購策略下的可控制前置時間；然而，其研究焦點只著重於前置時間的控制。而忽略其他影響存貨策略制定的重要因子，如設置成本或訂購成本。因此，本文考慮訂購成本的降低與前置時間的縮減有關，並以服務水準限制式取代目標函數中的缺貨成本項，找出最適的訂購數量、前置時間、請購點與訂購成本。另一方面，潛在的品質問題在可控制前置時間的研究文獻中亦常被忽略；換言之，無論是產品或製程的品質水準都假定處在最佳的狀態。然而，這並不符合實際的情況，因為不良品的產生在真實的生產環境中是很難避免的。本文的另一個重點即是在訂購量中含有不良品的存貨系統探討最適的訂購策略。
基於上述的考量，本論文提出四個存貨模型。第二章考慮訂購成本的降低與前置時間的縮短有關，包括訂購成本與前置時間之間關係為線性關係和對數關係，並以拉氏方法來求得經濟訂購量及最適的前置時間、訂購成本、請購點和全年期望總成本。其中2.3子節為假設前置時間內的需求量為常態分配；2.4子節中我們放寬了前置時間內的需求量為常態分配的假設，探討前置時間內需求量的分配為未知的情形。第三章是針對第二章所建立的存貨數學模式，進而考慮訂購量中含有不良品，並以拉氏方法來求得最適訂購策略。其中3.3子節為假設前置時間內的需求量為常態分配；3.4子節為前置時間內需求量的分配未知。我們同時對此四種生產存貨模型建立了兩個求解的演算法，且分別舉例說明其求解過程，並做敏感度分析，以瞭解參數值改變對於最佳解所造成的影響。最後，第四章則提出本研究的結論及未來的研究方向。

Inventory is a most important section in a business enterprise. We develop an inventory model in which the total relevant cost. In the early literature dealing with the inventory problem , lead time is always treated as a prescribed constant or a random variable either in deterministic or probabilistic model. Recently, many researchers felt doubtful about the uncontrollability of lead time and further embarked on the analysis of controllable lead time associated with the continuous review ordering policy. However, the researches conceptions focus on controlling lead time, and ignore other important factors influencing inventory strategies, such as setup cost or ordering cost. Hence, this paper consider that ordering cost associate with lead time, and instead of the stockout cost with service level. Our purpose is to minimize the total relevant cost by optimizing order quantity, lead time, reorder point and ordering cost. On the other hand, potential problems in controlling leading time research documentation commonly are ignored. That is the standards of product or process are in the assumption that the best situation. Nonetheless, It’s not agree with realistic situation，because defective goods are hardly to avoid in production process. Therefore another focus of this paper is the optimal order strategy when considers defective goods in order quantity.
Based on the above issues, we develop four inventory models in this thesis. In Chapter 2, we consider ordering cost reduction associate with lead time reduction, include the cases of the linear and logarithmic relationships between lead time and ordering cost reduction. We get the economic order quantity, optimial lead time, ordering cost, reorder point and annual expected total cost by Lagrangean method. Among Section 2.3,we assume that demand that follows a normal distribution during lead time; In Section 2.4, we relax the assumption of normal distribution, and discuss that the distribution of the demand is free. In Chapter 3, basing on the inventory model in Chapter 2 and considering defective goods in order quantity, we find the optimal order strategy by Lagrangean method. Among Section 2.3,we assume that demand that follows a normal distribution during lead time; In Section 2.4, we relax the assumption of normal distribution, and discuss that the distribution of the demand is free. Simultaneously build two algorithms for four inventory models and utilize the numerical examples to illustrate the effects of inventory systems associate with changing the values of parameters. Chapter 4 contains some concluding remark and future research.

目 錄
頁次
表目錄 三
圖目錄 五
符號一覽表 六
基本假設 七
第一章 緒論 1
1.1 研究動機與目的 1
1.2 文獻探討 2
1.3 研究方法 4
1.4 研究架構 5
第二章含服務水準限制式及訂購成本與前置時間有關之經濟訂購量模型 7
2.1 前言 7
2.2 符號說明與假設 9
2.2.1符號 9
2.2.2假設 9
2.3 需求機率分配為常態的基本模型的建立 10
2.3.1 線性函數模型 11
2.3.2 對數函數模型 14
2.3.3 數值範例 16
2.4 需求機率分配為未知的基本模型的建立 21
2.4.1 線性函數模型 22
2.4.2 對數函數模型 24
2.4.3 數值範例 26
第三章 含不良品、服務水準限制式及訂購成本與前置時間有關
之經濟訂購量模型 31
3.1 前言 31
3.2 符號說明與假設 32
3.2.1符號 32
3.2.2假設 32
3.3 需求機率分配為常態的基本模型的建立 33
3.3.1 線性函數模型 35
3.3.2 對數函數模型 38
3.3.3 數值範例 40
3.4 需求機率分配為未知的基本模型的建立 45
3.4.1 線性函數模型 46
3.4.2 對數函數模型 48
3.4.3 數值範例 50
第四章 結論 55
4.1 主要研究成果 55
4.2 未來研究方向 56
參考文獻 57
附錄A i
附錄B iii
附錄C v

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