Research On EOQ Model For Perishable Items With Partial Lost Sales

The topic selection comes from the National Natural Science Foundation Project (NO.70771034),the Foundation for the Author of National Excellent Doctoral Dissertation of PR China (NO.200565), the PhD. Programs Foundation of Ministry of Education of China (NO.20060359007) and the Major Project of Key Research Base on Humanity and Social Science Education of Department of Guangdong Province (NO. 08JDXM63003).The inventory is an important sector to link production and sale, solving the problem of unbalanced supply and demand. It's of significance to determine proper ordering lot size and period. During recent years, the research on inventory control has made much more progress. On the basis of research on inventory control at home and abroad, this thesis makes some research as follows:This paper proposes an inventory model of deteriorating items with finite service rate. In the model demand rate is assumed to be exponentially decreasing. Shortages are allowed and backordered with fixed ratio. This model solves the time-varying inventory level and exhibits several cost function according to the inventory level. In order to simplify the calculation, Taylor series is used to approximately calculate average of total cost function. This model proves the uniqueness and existence of the optimal solution of the approximate cost. And some numerical examples are presented to illustrate the rationality of the approximate calculation.This paper models the problem of non-instantaneous deteriorating stochastic inventory. After entering the warehouse, the stocks can maintain quality in a span and then begin to deteriorate. This model supposes during this period stocks are affected by some environmental factors that advance or postpone deterioration and time interval is an exponential distribution random variable. Shortage is allowed in the model and backlogging rate is a linear function of instantaneous inventory level. The model analyzes the condition of existence and uniqueness of optimal sale and shortage interval with the object function of expected profit per time unit. And this model presents some numerical examples to supplement and perfect the analysis.The research results presented above not only enrich the content of inventory control theory, but also widen the applied areas of supply chain coordination model, and provide more sufficient scientific evidence for decision makers making inventory decision.