Study On The Inventory Models Of Reverse Logistics For Sellers With Resalable Returns

Return is a very normal commercial phenomenon in the circulation of many industries. Due to its uncertainty, dispersion and variation, the originally complicated inventory problem becomes more difficulty to control and manage. The return flows of products occurred by unwanted product make sellers have to distinguish between products yet to be overhauled and serviceable, which leads to a two-echelon inventory system. Thus, investigations on adequate echelon stock control strategies are of great significance in this context.This thesis, which is on the basis of analyzing development of inventory policy, has studied the reverse logistics inventory control problems for the sellers with resalable returns, and presented several reverse logistics inventory models for the sellers with resalable returns by analyzing the characteristics of demand and return.Based on the research of EOQ model, this paper presents an inventory model of determinate demand and return with lagged time and complete backlogging for general products. We derive an expression for the optimal ordering quantity which makes the average inventory cost smallest. A numerical example and sensitivity analysis are presented to illustrate the model.Then, based on the model in the preceding chapter, new model with determinate demand and return obeyed Poisson Distribution was developed. The average total inventory cost function is strictly convex. This thesis analyses the existence and optimality of the optimal solution, derives an expression for the optimal ordering quantity which makes the average inventory cost smallest. A numerical example and sensitivity analysis are presented to illustrate the model, and demonstrate that each parameter has different sensitivity to the optimal ordering quantity and the average total inventory cost.Finally, this paper explored a single-period inventory control problem with resalable returns for seasonal products when demand distribution is unknown but the mean and variance of the demand are assumed to be known. A single order is placed before the season starts. We assume that a product can be returned and resold infinitely many times. With the goal of maximizing retailer's total expected profit, authors used newsboy model to construct a single-period inventory model with resalable returns, in which only the mean and the variance of the demand are known,and determine the order quantity that maximizes expected profit. A numerical example and sensitivity analysis are also presented to look at the relation between return rate, relative profit margin and the performance of the optimal order rule. The theoretical evidences are provided for the sellers to make better reverse logistics inventory management decisions.