Remanufacturing lotsizing with stochastic lead-time resulting from stochastic quality of returns
研究了回收产品质量不确定性导致的恢复时间随机性，给出了优化恢复计划的解析表达式，并通过数值实验分析了忽略质量不确定性对成本的影响。
In the current paper, we model the duration of recovery of used products as a variable that depends on each unit’s quality. Because of the uncertainty related to returned units’ quality, the necessary time for the recovery of a lot is a random variable. We provide analytical expressions for the optimisation of recovery planning decisions under different assumptions regarding quality and demand characteristics. In addition, through an extensive numerical study, we examine the impact of the different parameters on the necessity to consider explicitly the stochastic nature of recovery lead-time. Moreover, we discuss the advisability of establishing procedures for the classification of returns according to their quality condition. As our findings indicate, overlooking quality uncertainty can increase related costs considerably because of poor process coordination. Furthermore, ignoring variability may result in undue overestimation of the efficiency of lot-sizing policies. On the other hand, the establishment of quality assessment procedures is worthwhile only when the stochastic behaviour of quality cannot be taken into account explicitly.