Extended Research on an Imperfect Process Production-inventory Model with Deteriorating Items under Two Dispatching Policies

Abstract

先進先出(FIFO)與後進先出(LIFO)爲存貨管理最常預設的策略，其選用必需符合企業實際生產情況，尤其當產品爲易受製程偏移影響之損耗性商品。本研究首先針對不完美製程損耗性商品提出FIFO策略下之生產存貨模式，隨後應用指數函數之泰勒展開式推導出近似最佳生產運轉時間之封閉解，並以數值範例說明模式精確性。再者，研究中將所獲得之模式與先前提出之LIFO策略生產存貨模式比較，並獲致損耗性商品於不完美製程生產時，LIFO存貨派用策略優於FIFO策略之結論。最後，透過敏感度分析展現FIFO策略下各參數之影響。

The First-In-First-Out (FIFO) and the Last-In-First-Out (LIFO) are the most general presumption policies of the inventory management. These presumptions are carefully considered in line with the actual practice of most business entities, especially when the merchandise or goods which have the deteriorating property affected by an imperfect production process. In this study, we firstly propose a production-inventory model for deteriorating items under an imperfect production process with FIFO inventory dispatching policy. Then, a closed-form solution of a near-optimal production uptime will be derived by utilizing Taylor series expansion of an exponential function. A numerical example is provided to argue the model’s fidelity. Also, a comparison with our previous research work-an LIFO policy production-inventory model is made. We conclude that when a deteriorating item is produced by an imperfect process, the LIFO inventory dispatch policy would be a better decision than the FIFO. Finally, sensitivity analysis is given to investigate the impacts that various parameters have in FIFO policy choice.