This paper presents another maintenance policy for a group of units under finite operating horizon. A group of identical units are subject to random failures. Group maintenances are performed to all units together at specified intervals, and the failed units during operation are remained idle until the next group maintenance set-up. Unlike the traditional assumption of infinite operating horizon, we adopt the assumption of the finite operating horizon which reflect the rapid industrial advance and short life cycle of modern times. The units are under operation until the end of the operating horizon. Further, the operation of units are extended to the first group maintenance time after the end of the horizon. The total cost under the proposed maintenance policy is derived. The optimal group maintenance interval and the expected number of group maintenances during the horizon are found. It is shown that the proposed policy is better than the classical group maintenance policy in terms of total cost over the operating horizon. Numerical examples are presented for illustrations.

Abstract
 1. 서론
 2. 제안정책하의 총비용과 최적 보전주기
 3. 최적 그룹보전주기의 탐색과 특성
 4. 수치예제를 통한 최적해의 탐색
 5. 결론
 6. References

• 유영관(한라대학교 경영학과) | Young-Kwan Yoo Corresponding Author