碩士 / 國立屏東科技大學 / 工業管理系所 / 105 / Inventory is always important issue in production systems. Traditional lot size models of Economic Production Quantity assumed that merchandises could store without time limitations. However, most of value and quantity of merchandises would age, deteriorate, volatilize or corrupt 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. However, It’s function is gradually degrading with time. 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. In fact the actual situation of the degradation will not be unlimited growth, but because of the factors of their space or nutrients limit the increase. Therefore, this thesis use Logistic model to determine the degradation curve and each batch of merchandises degradation rate follows Log-Normal distribution and built an EPQ model for deteriorating Items with Logistic degradation curve. Finally, the study compared the traditional EPQ model; the deteriorating Items EPQ model; the stock life approach to EPQ model for deteriorating Items and the proposed EPQ model on optimizing the production cycle and minimizing 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.
| Identifer | oai:union.ndltd.org:TW/105NPUS5041002 |
| Date | January 2017 |
| Creators | Lin, Chih-Min, 林志珉 |
| Contributors | Wu, Ji-Cheng, 吳繼澄 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 71 |
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