A Spare Ordering Policy with Random Lead Times

Yoon, S.P.; Cho, T.C.

Journal of Korean Society for Quality Management > Volume 35(1); 2007 > Article

Journal of Korean Society for Quality Management 2007;35(1): 20-.

조달기간이 확률적인 경우의 예비품 주문정책

윤성필, 조태연

성균관대학교 시스템경영공학과

A Spare Ordering Policy with Random Lead Times

S.P. Yoon, T.C. Cho

Department of Systems Management Engineering, Sungkyunkwan University

ABSTRACT

A generalized spare ordering policy is treated in this paper. If the operating unit fails before a scheduled ordering time an expedited order is placed at the failure time instant, otherwise a regular order for a spare is placed at the scheduled time. The original unit is replaced when the ordered spare is delivered. The lifetime, regular and expedited lead times have general distributions. The problem is to find the optimum ordering time which minimizes the expected cost rate including the observation, ordering, uptime and down-time costs. Some properties regarding the optimal policy are derived. To explain the spare ordering policy a numerical example is also included.

Key Words: Ordering policy;Spare;Maintenance;