基於貨架壽命觀點之損耗性商品經濟生產批量模式

A Stock Life Approach to EPQ Model for Deteriorating Items

黃雨旋(Yu-Hsuan Huang)

指導教授 ： 吳繼澄

國立屏東科技大學/管理學院/工業管理系所/碩士(2016年)

摘要

傳統經濟生產批量模式大多假設商品可以無限期儲存，但實際上許多商品在持有的過程當中會發生腐敗、揮發、退化或變質等現象，使得其價值及數量隨時間遞減，這類存貨稱之為損耗性商品。目前有關損耗性商品之存貨研究，皆假設商品的壽命服從某特定機率分配，再根據其損耗率推導各時期之存貨數量函數，進一步建立存貨模式並求得經濟生產批量。然而，損耗性商品在未售出前置於倉庫貨架並未真正使用，以可靠度操作壽命觀點制定存貨政策勢必與現實不符。本研究提出損耗性商品之貨架壽命觀點，即商品品質特性或功能隨時間逐漸退化，當退化量超出特定水準時，則定義商品失效，再基於貨架壽命觀點考慮退化率服從對數常態分配建立損耗性商品之經濟生產批量模式。最後透過數值範例說明最佳生產週期及最小單位總成本求解程序，結果並與傳統經濟生產批量模式及損耗性商品之經濟生產批量三者進行比較，同時也對重要參數進行敏感度分析，使管理者能深入了解各參數變動對每單時間總成本所造成的影響，進而作為決策參考。

關鍵字

損耗性商品 ； 經濟生產批量 ； 操作壽命 ； 貨架壽命 ； 退化率

並列摘要

Traditional lot size models of Economic Production Quantity assumed that merchandises could store without time limitations. However, most of merchandises would corrupt, volatilize or deteriorate during the process of holding practically. Those phenomenons let the value and quantity of merchandises decrease with time-varying. This kind of inventories so called Deteriorating Items. Currently, related studies supposed the deteriorating rate of operating life as a constant or following a distribution, and to establish the function for the EPQ models refer to the deteriorating rate. In fact, stocked deteriorating items are not operated prior to being purchased. Therefore, determining stocking strategy by the perspective of general operating lifetime on reliability should not match practical problems. This thesis purposed the perspective of stocked deteriorating items’ lifetime. When the degradation exceeds specific levels, the item would be defined as failure. Moreover, we considered degradation rate follows Log-Normal distribution and built an EPQ model. Finally, the study compared the traditional EPQ model; the deteriorating Items EPQ model and the proposed EPQ model on minimize total unit costs through a numerical example. In the meantime, we adopted sensitivity analyses on important parameters. The result could be the reference for administrators to deeply understanding variations of each parameter.

並列關鍵字

Deteriorating Items ； Economic Production Quantity ； Operating Life ； Stock Life ； Degradation Failure

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