生产线随机崩坍情形下的变质品EPQ策略

Optimal Production-inventory Policy for Deteriorating Items with Random Machine Breakdown

变质品生产过程,可能率先出现"次品"的不稳定生产情形,随后机器崩坍;生产状态稳定性迁移时机、机器崩坍时间、维修时间皆乃随机变量;同时,企业无法观测当期需求,只能根据前期需求而随机地安排启动生产时刻.理论模型及数值算例皆表明,此种情况下,企业可以非等周期生产,存在组织生产次数(N)与生产率(P)的优解.敏感度分析看出,当需求拖后率增加、变质率+次品率降低时,企业成本显著降低,但首期生产启动时刻、生产率几乎没有变化.

The paper develops integrated production und inventory models for deteriorating items in which the production facility may not only shift from an ＇in-control＇ state to an ＇out-of-control＇ state but also may break down at any random point during a production run. In addition, the corrective repair time is stochastic. Furthermore, enterprise can＇t observe present demand; it had to stochastically start setup based on the previous demand. Model and numerical example prove that such system may program production in a non-identical- cycle, gain the optimal production run time and the optimal productivity. Sensitivity analysis indicates that, when the partial backlogging demand increases, the deterioration rate and defective rate decrease, the total cost will drop. However, the productivity and the setup time of first production run hardly change.