Amount Of Shortage Research Articles

Backorder fuzzy inventory model under function principle

In this paper, the fuzzy inventory model is discussed, especially in the case of permitting backorder under the fuzzy environment of fuzzy demand, fuzzy order cost, fuzzy inventory cost, and fuzzy backorder cost. We use the function principle, instead of the extension principle, to calculate the total fuzzy inventory cost. We also apply the median rule to find the optimal economic order quantity (EOQ) and shortage quantity.

An approximation to the continuous review inventory model with perishable items and lead times

A continuous review perishable inventory model based on approximations to the expected outdating, the expected shortage quantity, and the expected inventory level is developed to determine a best ( Q, r) ordering policy under a positive order leadtime when the total expected average cost per unit time is minimized. The approximation method is simple and verified by a comparison with the Weiss model. The results reveal that the mean absolute deviation from the optimal total expected average cost per unit time is only 0.58%. This paper also compares the proposed model to the conventional model with no perishability. A value is given to the item lifetime indicating when an approximate answer approaches closely to the conventional ordering policy. Finally, a simulation model written in SIMSCRIPT II.5 is used to validate the approximate results.

Designing a pull-type parts procurement system for international co-operative knockdown production systems

In this paper, a conceptual framework for designing a parts procurement system for international co-operative knockdown production systems is proposed. Two types of pull-type parts procurement models that contain both a backorder function which modifies the backlog carried over from the last period and emergency delivery compensating for component part shortages, are formulated, and the effects of emergency delivery on the probability of stock out and the mean value of shortage quantity is analysed. Using these results, a computational procedure for determining an economic buffer stock level and emergency delivery rate or level which assures system reliability for a given performance level and minimizes the sum of inventory and emergency procurement costs, is presented.

The Economic Lot Sizes in Multistage Production Systems

Abstract This article develops a model for a single-product multistage production-inventory system with static deterministic demand, where the product moves between the stages in a serial fashion. In this model, it is assumed that the unfilled demand of the finished product is backlogged. Overproduction (with limitation) is allowed at the different stages so that each stage t may produce ki batches once every ki cycles. The decision variables for each stage i are the number of batches per run ki the batch size Qi , and the shortage quantity of the finished product Qs . These are determined by minimizing the total cost per unit time which includes the inventory holding cost, the shortage cost, and the setup cost. The problem is also considered for the case with storage constraints at the different stages.