由於企業間的競爭日趨激烈，各企業為了節省資本支出，對於昂貴的機器設備，開始採取租賃的方式，並將其維修及預防保養的工作委託專業的公司處理。通常，當設備租賃時，出租者和承租者需要簽訂一份租賃合約規範雙方之權利義務，有些合約中甚至包含設備預防保養及維修的方式。為了協助出租者於設備出租時，訂定合約內設備預防保養及維修的策略，本論文針對具韋伯壽命分配之設備推導最佳預防保養策略。假設在租賃期內，設備採取週期性預防保養，且預防保養的方式為固定失效率降低法，設備失效時以小修的方式處理，根據上述保養及維修方式，建構數學模式並尋求最佳的預防保養次數、保養程度，使得期望總成本最低，最後透過數值範例加以驗證。

With intense competition among business, enterprises need to save capital expenditure. Equipment leasing will be an cost-effective method for high-cost equipment. The corrective and preventive maintenance for leased equipment is also outsourced to specialized maintenance firms. However, before leasing equipment, lessor and lessee must sign a lease contract to specify the privilege and obligation of both sides, which includes the ways of corrective and preventive maintenance of the equipment. In order to assist lessor to determine the terms of corrective and preventive maintenance of equipment after equipment leasing, this thesis develops a mathematical model to derive the optimal periodical preventive maintenance policy for leased equipment with Weibull life-time. Within a lease period, any equipment failures are rectified by minimal repair. To reduce equipment failures, additional preventive maintenance actions using fixed failure rate reduction method are carried out periodically during the lease period. The structural properties of the optimal policy are investigated, the optimal number of preventive maintenance actions and the corresponding maintenance degrees are jointly determined. Finally, the cost reduction by providing preventive maintenance is evaluated through numerical examples.

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