Analysis of a Production/Inventory System Subject to Random Disruptions
研究一个不可靠瓶颈生产/库存系统，提出(s, S)生产策略，分析最优参数并设计启发式方法，发现降低准备成本在可靠系统中更有效，且不可靠系统需更高安全库存。
In this paper we study an unreliable bottleneck production/inventory system with a constant production and demand rate that is subject to random disruptions. We assume that the restoration times are constant, the time between breakdowns is exponential, the production setup cost and/or setup time is positive, and excess demand is backordered. We propose an (s, S) production policy for such systems and develop expressions for the operating characteristics of the system. The properties of the policy parameters that minimize the expected total cost rate are investigated and a procedure for finding their optimal values is developed. In addition, we devise and test a simple heuristic procedure for finding near optimal production policies. The results of a numerical experiment suggest that (i) setup cost reduction is more effective in reducing total operating cost when the production system is more reliable, (ii) setup cost reduction in unreliable production systems results in higher optimal safety stock level, and (iii) proper determination of the safety stock levels is extremely important in Just-in-Time systems, which are susceptible to disruptions.