傳統最佳經濟製造批量(Economic Manufacturing Quantity) 模型基本假設之一，是產品品質均是完美無瑕的，但在實務上， 產品品質通常是製程的函數，生產機器設備在經過長期使用之後， 可能會發生老化 (aging) 的現象，並導致製程失控 (out-of-control) 而產生不良品，本研究探討此老化生產系統下， 不完美預防保養(Imperfect Preventive Maintenance)與產品保證策略對最佳經濟製造批量模型之影響。 1. 不完美預防保養政策對最佳經濟製造批量模型影響部份 對機器設備逐漸老化的生產系統，若能在生產週期內做適度的預防保養 將可使製程的失效率減緩，進而降低不良品的產生。 然而，預防保養工作可能因人為疏失，或受經費限制等因素的影響，而產生 非完美預防保養之現象。本研究將探討預防保養有錯誤發生時，對傳統 EMQ 模型之影響。文中提出兩個預防保養時程策略，並推導出於各策略下之最佳 預防維修保養時程與最佳經濟製造批量，最後舉數值範例來說明此二策略績效， 並與一般檢驗政策做比較。 2. 產品保證策略對最佳經濟製造批量模型影響部份 此模型主要探討當廠商對於其產品在保證期內失效提供免費小修 (free minimal repair)之保證策略時，對傳統 EMQ 模型之影響。由於保證成本與不良品數目多寡有關， 對一老化生產系統而言，若縮短生產週期，減少製造批量，以保持製程儘量處於「控制」狀態，將可降低不良品產生數量，降低保證成本，但卻因為整備 (set up) 次數之增加而使得整備成本增加。反之，延長生產週期雖可降低整備成本，但卻增加保證成本。 因此，本研究針對此問題建構一新模型，並求得最佳生產週期，使得單位產品之期望 總成本最低。文中並探討最佳生產週期對系統參數之敏感性分析，最後舉數值範例以 說明。

In the traditional Economic Manufacturing Quantity model, there is a basic assumption about the production system, that is, the production process is perfect and continuously produces conforming items. This assumption however may not be true in practice. A production system will deteriorate due to usage or age such as corrosion, fatigue and cumulative wear. Under these circumstances, we investigate the effects of imperfect preventive maintenance and free repair warranty on the EMQ model for a deteriorating production system. These two effects are discussed below. 1. The effects of imperfect preventive maintenance on the EMQ model: We consider the case where the shift of the production process is generally distributed and the maintenance action is imperfect and may lead a production system to a worse condition. Two commonly used maintenance strategies are proposed: equally-spaced and equally-cumulative-hazard. Under both maintenance strategies, optimal maintenance policies and the optimal production run length can be obtained. Some numerical examples are also provided to illustrate the performance of the optimal policies. 2. The effects of free repair warranty policy on the EMQ model: Assuming the shift of the production process is exponentially distributed and the products are sold with free minimal repair warranty, we derive an unique optimal production run length which minimizes the expected total cost per item. Three special cases which provide bounds for searching the optimal production run length are investigated and a sensitivity analysis is conducted to study the effects of the model parameters on the optimal production run length. Finally, numerical examples are given to evaluate the performance of the optimal production run length