An improved solution to replenishment lot size problem with discontinuous issuing policy and rework, and the multi-delivery policy into economic production lot size problem with partial rework

Recently, in Expert Systems with Applications journal, Chen, Wu, Chiu, and Lee (2012) present an alternative optimization solution process to determine the optimal replenishment lot size with discontinuous issuing policy considering imperfect rework process and multiple shipments. Simultaneously, Chiu, Chiu, and Yang (2012) solve a multi-delivery policy into economic production quantity with partial rework. Both papers consider the number of shipments as a fixed and a given value. In this paper both the optimal replenishment lot size and the optimal number of shipments are derived jointly for the inventory models of Chen et al. (2012) and Chiu, Chiu, et al. (2012). Two easy to apply solution procedures are proposed. The solutions reported in this paper are better than the solutions of Chen et al., 2012 and Chiu, Chiu, et al., 2012.