Comments on a Paper by S. G. Allen and D. A. D'Esopo: 'An Ordering Policy for Repairable Stock Items,'

摘要

The authors of a recent article considered an inventory model for repairable items with a positive condemnation rate. In deriving their expression for the long-run expected shortages per unit time, the authors used several approximations, only one of which was made explicit. It is the purpose of this commentary to point out that an exact expression for the long-run expected shortages per unit time can be obtained in a simple manner, and also to point out the unmentioned approximations used by the previous authors. A numerical comparison is made of the exact and approximate expressions, and it is seen that the approximate expression is very poor. (Author)