This paper investigates the instantaneous economic order quantity model by allocating the percentage of units lost due to deterioration in an on-hand inventory by framing promotional effort cost and variable ordering cost. The objective is to maximize the net profit so as to determine the order quantity, promotional effort factor, the cycle length and number of units lost due to deterioration. For any given number of replenishment cycles the existence of a unique optimal replenishment schedule are proved and mathematical model is developed to find some important characteristics for the concavity of the net profit function. Numerical examples are provided to illustrate the results of proposed model, which benefit the retailer and this policy is important, especially for wasting of deteriorating items. Finally, sensitivity analyses of the optimal solution with respect to the major parameters are carried out.
In this paper, we develop an inventory model for deteriorating items with exponential time dependent demand rate. In this proposed model, shortages are allowed and partially backlogged. The model is explained with the help of numerical examples. We also show that total cost function is convex with time. Sensitivity analysis of the optimal solution with respect to various parameters of the system is given and results are discussed in details. Taylor’s series expansion is used for finding closed form optimal solution. Some results have been also obtained.
This paper addresses the application of group Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) to Multiple Criteria Decision Making (MCDM), for assisting decision makers by evaluating, ranking and selecting material handling equipment (MHE). The present study considers engineering economy as one of the erudite tool for performance evaluation of said equipment in the integrated and synergetic way. Lastly, incremental analysis is used for final ranking of the equipment under inquisition.
This paper considers a multi period serial production systems for one product and deals with the problem of planned lead-time calculation in a Material Requirement Planning (MRP) environment under probabilistic lead times. It is assumed that lead times for all stages have the same distribution with different parameters. A MRP approach with periodic order quantity (POQ) policy is used for the supply planning of components. The objective is to minimize the sum of fixed ordering, holding and backlogging costs. A mathematical model is suggested and then an optimal planning lead-time, ordering quantity and periodic time are determined.
During the past two decades, there has been a growing concern on environmental issues around the world. Firms try to provide better production plans to recycle their used materials to reduce pollution from environment. In fact, lack of management in municipal solid waste for methods of collecting, disposal and processing of them can be significant damage to the environment, This paper presents a mathematical model for pet waste management, which plays essential role on municipal solid waste. The modeling formulation is a nonlinear probable mathematical programming model for chemical recycling the PET waste. In this model, the optimal amount of waste is determined by considering collected operations of reverse logistics and chemical recycling when demand is under uncertainty.
One of the primary concerns on supply chain management is to select appropriate suppliers based on different criteria, which are often in serious conflict. In this paper, we present a fuzzy TOPSIS technique to prioritize suppliers on reverse logistic network based on different criteria and then the proposed model of this paper applies fuzzy linear programming technique to determine optimum order quantity associated with each supplier. There are three criteria associated with each supplier including technical skills, equipment and ability to analyze. The implementation of the proposed method has been demonstrated in case study.