The Further Researches On Some EOQ Models

The fundamental objective of studying the logistics system is to reduce thetotal cost of logistics. But the inventory cost of items is of much more proportionin the total cost of logistics. Therefore, studying the theory and methods ofinventory control is very significant for reducing the total cost of logistics. Also,it is a hot spot of logistics theory research.In the first section, This dissertation starts with the concrete problems thatdecision makers may encounter while they use the existing inventory theory tomake practical inventory decision, and makes further extensive study on thetraditional inventory control theory from di?erent aspects. The details are givenas below:1. The losing in inventory is only relative to the stocks in the traditionalinventory models for perishable items. In the case that shortage are allowedto occur, we consider that the losing in inventory is correlated with stocks andtime. We also consider the correlation between the variety and the losing ininventory is nonlinear. This paper use view points and methods di?erent fromsome references, and studies its optimal policy.2. We studied the inventory models with time-limited free back-orders andtime-varying demand. The paper is the first to integrate the problem of payingthe purchasing cost in delay to the model. It proposes inventory control modelsfor finding the optimal order policy under three rules of the delayed payment.3. An inventory model placing orders with multi-suppliers with capacityconstrain is established under stochastic demand.4. In second section, we use a method of Partial Least Squares to fit theforecasting models for the achievements of sprint. And make an analysis on thedata of physique, function and quality got from the test of a group of 13-year-oldUrgy boys. Every index factor proportion is taken into account. We also makesome precision analysis.