A note on the upper bound for the optimal work size

Mi (2002) recently considered a two-dimensional optimization problem for the optimal age-replacement policy and the optimal work size. In order to find (y*, T*), Mi (2002) found the optimal age-replacement policy T*(y) for each fixed work size y, and then searched for the optimal work size y*. When applying this approach, for each fixed work size y, Mi (2002) obtained the bounds for T*(y). However, no bound for the optimal work size y* was derived. In this note, the results on the upper bound for the optimal work size y* are given.