This paper deals with the effects of inflation and time discounting on an inventory model with general ramp type demand rate, time dependent (Weibull) deterioration rate and partial backlogging of unsatisfied demand. The model is studied under the replenishment policy, starting with shortages under two different types of backlogging rates, and their comparative study is also provided. We then use the computer software, MATLAB to find the optimal replenishment policies. | Yugoslav Journal of Operations Research 23 (2013) Number 3, 441-455 DOI: A STUDY OF INFLATION EFFECTS ON AN EOQ MODEL FOR WEIBULL DETERIORATING/AMELIORATING ITEMS WITH RAMP TYPE OF DEMAND AND SHORTAGES M. VALLIATHAL Chikkaiah Naicker College, Erode,Tamilnadu, 638004, India, balbal_ba@ R. UTHAYAKUMAR Gandhigram University, Gandhigram, Tamilnadu, 624302, India, uthayagri@ Received: August 2011 / Accepted: March 2013 Abstract: This paper deals with the effects of inflation and time discounting on an inventory model with general ramp type demand rate, time dependent (Weibull) deterioration rate and partial backlogging of unsatisfied demand. The model is studied under the replenishment policy, starting with shortages under two different types of backlogging rates, and their comparative study is also provided. We then use the computer software, MATLAB to find the optimal replenishment policies. Duration of positive inventory level is taken as the decision variable to minimize the total cost of the proposed system. Numerical examples are then taken to illustrate the solution procedure. Finally, sensitivity of the optimal solution to changes of the values of different system parameters is also studied. Keywords: Inventory, ramp type of demand, inflation, partial backlogging. МSC: 90B05. 1. INTRODUCTION For long, inventory models have dealt with the case where demand is either a constant or a monotonic function. Constant demands take place in the fully developed 442 М. Valliathal, R. Uthayakumar / A Study of Inflation Effects on an EOQ Model stage of the item, and monotonic in the beginning or at the last stage of the cycle of life. Existing inventory models deal with these types of demand functions, but in practice, it is not possible. The demands of fashionable goods increase up to a certain level and after that become steady. Such type of demand functions is known as ramp type of demand. (See Skouri et al. [20]). .
