Studies of optimal ordering policies for perishable commodities

Abstract

Problems associated with perishable or outdating products arise in many areas of inventory and production man agement. Many commodities exist whose value does not remain constant over time during transportation, holding stock, etc. Significant work has been done to describe optimal ordering policies for items which have a fixed lifetime. In this paper, per ishable inventory models subject to stochastic procurement leadtinie both on LIFO (Last In First Out) and FIFO (First In First Out) issuing policies are considered with cither zero or 1 unit leadtinie. First, assumptions and notation used throughout the paper are given. FIFO and LIFO models are then con structed, and the existence of the optimal ordering policies and theirpropertiesare clarified. Finally, significantresults are illustrated for the relationship among inventory on hand, delay probability of procurement and optimal ordering policies.     

The effects of transportation lead-time and safety stock in international co-operative knockdown production systems

Abstract

Abstract. In international co-operative knockdown production systems (ICKDPS), much longer transportation lead-time than production lead-time to procure component parts is required, because the parts are generally containerized by ship. In this paper, in order to determine an economical buffer stock level for a more reliable ICKDPS, a pull-type ordering system which considers the backorder for compensating for shortage of component parts is developed for the ICKDPS as a three-stage production, inventory and transportation system with the concept of 'just-in-time’ production systems. In addition, the effects of transportation lead-time and buffer stock level on the quantity of backlogs and the probability of requirement are clarified by simulation.