臺灣博碩士論文加值系統

由Harris (1915) 發展並經由 Wilson (1934) 所推廣的傳統經濟訂購量存貨模式中，假設存貨的減少僅是因為產品需求所導致，產品可以無限期儲存且需求率為固定常數。但是，在日常生活中，存貨的退化（deterioration）是很普遍的現象。譬如藥物、食品、蔬菜及水果等，可能因存放的時間過久，使得新鮮度降低，產生退化（腐壞）的現象，因而造成存貨數量的減少。因此，擬訂此類物品之存貨策略時，產品退化所造成的存貨數量減少就不可被忽略。再者，產品的需求率也並非固定不變。貨架上存貨數量的多寡，往往會影響消費者購買的意願。商店展示大量的存貨，將產生刺激消費的作用，使得消費者的需求增加。另一方面，產品需求亦可能隨著時間的變化而呈指數遞減的型式。此外，在現實生活中，很多存貨物品（例如流行性商品或民生必需品）在業者發生缺貨時，只有部分的消費者願意等候欠撥，而另一部分的消費者因不願等候而轉向其他競爭廠商購買。因此，等候廠商補貨所需時間的長短往往成為消費者是否願意接受欠撥的主要關鍵。
本研究的目的在建立需求變動且部分欠撥的退化性產品存貨模式，其中，假設產品的壽命服從指數分配（亦即產品退化率為固定常數）且允許缺貨而缺貨數量為部分欠撥，欠撥率假設為等候廠商下次補貨所需時間的遞減函數。第二章建立需求和存貨水準呈線性關係且部分欠撥的退化性產品存貨模式。第三章則探討需求和存貨水準有關且部分欠撥的退化性產品存貨模式。第四章討論需求呈指數遞減且部分欠撥的退化性產品存貨模式。文中對所建構的數理存貨模式利用傳統的最佳化原理找出最適的訂購策略，以使存貨相關總成本為最少。最後，舉例說明模式的求解過程並對各參數做敏感性分析。

Classical inventory models developed by Harris(1915) and extended by Wilson(1934) deal with constant demand rate of the product. They assumed that products decrease just because of the demand in the market and products’ storing have no deadline. However, in daily life, the deteriorating of goods is a very common phenomenon. Pharmaceuticals, foods, vegetables and fruit are a few examples of such items. For longtime storing, they are no more fresh. The deteriorating items result in the decreasing of the products. Therefore, the loss due to deterioration cannot be neglected.
Moreover, the demand rate is not always constant. The presence of inventory has a motivational effect on the people around it. It is a common belief that large piles of goods displayed in a supermarket will lead the customer to buy more. On the other hand, the demand rate will probably be an exponentially declining function of time. Besides, some customers would like to wait for backlogging during the shortage period, but the other would not. In fact, the longer the waiting time is, the smaller the backlogging rate would be. Therefore, the length of waiting time is the key point whether the customers would like to wait for backlogging or not.
In this study, inventory models are developed for deteriorating items with variable demand rate and shortages, in which the rate of deterioration is assumed to be constant. In addition, the shortages are partial backlogging, and assuming the backlogging rate to be inversely proportional to the waiting time for the next replenishment. In Chapter 2, we first develop an Inventory model for deteriorating items with the demand rate linearly dependent on the instantaneous stock level and partial backlogging. In Chapter 3, we consider an Inventory model for deteriorating items with inventory-level-dependent demand rate and partial backlogging. In Chapter 4, we present an Inventory model for deteriorating items with exponential declining demand rate and partial backlogging. The optimal solution procedures for the present problems are provided. Numerical examples are presented to illustrate the models, and the sensitivity analysis of the optimal solution with respect to parameters of the systems are also carried out.

目 錄
目次﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒Ⅰ
表次﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒Ⅲ
圖次﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒﹒Ⅲ
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 本文結構.................................................4
第二章 需求和存貨水準呈線性關係且部分欠撥的退化性產品存貨模式5
2.1 符號說明與假設條件.......................................5
2.2 模式建立.................................................7
2.3 數值範例與敏感性分析....................................12
第三章 需求和存貨水準有關且部分欠撥的退化性產品存貨模式..15
3.1 符號說明與假設條件......................................15
3.2 模式建立................................................16
3.3 數值範例與敏感性分析....................................21
第四章 需求呈指數遞減且部分欠撥的退化性產品存貨模式.........25
4.1 符號說明與假設條件......................................25
4.2 模式建立................................................26
4.3 數值範例與敏感性分析....................................30
第五章 結論.................................................34
5.1 主要研究成果............................................34
5.2 後續研究方向............................................34
參考文獻....................................................36
表次
表2-1 參數變動對最佳解的影響...............................13
表3-1 參數變動對最佳解的影響...............................23
表4-1 參數變動對最佳解的影響...............................32
圖次
圖2-1 存貨水準與時間關係圖..................................7
圖3-1 存貨水準與時間關係圖.................................16
圖4-1 存貨水準與時間關係圖.................................26

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