%0 Journal Article
%T A New Mathematical Inventory Model with Stochastic and Fuzzy Deterioration Rate under Inflation
%A Bahar Naserabadi
%A Abolfazl Mirzazadeh
%A Sara Nodoust
%J Chinese Journal of Engineering
%D 2014
%R 10.1155/2014/347857
%X This paper develops an inventory model for items with uncertain deterioration rate, time-dependent demand rate with nonincreasing function, and allowable shortage under fuzzy inflationary situation. The goods are not deteriorating upon reception, but the deteriorating starts after elapsing a specified time. The lead time and inflation rate are both uncertain in the model. The resultant effect of inflation and time value of money is assumed to be fuzzy in nature and also we consider lead time as a fuzzy function of order quantity. Furthermore the following different deterioration rates have been considered: for the first case we consider fuzzy deterioration rate and for the second case we assume that the deterioration rate is time dependent and follows Weibull distribution with three known parameters. Since the inflation rate, deterioration rate, and the lead time are fuzzy numbers, the objective function becomes fuzzy. Therefore the estimate of total costs for each case is derived using signed distance technique for defuzzification. The optimal replenishment policy for the model is to minimize the total present value of inventory system costs, derived for both the above mentioned policies. Numerical examples are then presented to illustrate how the proposed model is applied. 1. Introduction Many of the physical goods undergo decay or deterioration over time. Commodities such as fruits, vegetables, and foodstuffs are subject to direct spoilage during storage period. The highly volatile liquids such as gasoline, alcohol, and turpentine undergo physical depletion over time through the process of evaporation. The electronic goods, radioactive substances, photographic film, and grain deteriorate through a gradual loss of potential or utility with passage of time. The deteriorated items repairing is a major problem in the supply chain of most of the business organizations. The first attempt to describe optimal ordering policies for deteriorating items was made by Ghare and Schrader [1]. Later, Covert and Philip [2] derived the model with variable deteriorating rate of two-parameter Weibull distribution. Inventoried goods can be broadly classified into four metacategories:(1)obsolescence which refers to items that lose their value through time due to rapid changes of technology or the introduction of a new product by a competitor;(2)deterioration which refers to the damage, spoilage, dryness, vaporization, and so forth of the products;(3)amelioration which refers to items whose value or utility or quantity increases with time;(4)no
%U http://www.hindawi.com/journals/cje/2014/347857/