Research On The Inventory Problems Based On Three Types Of Fuzzy Demands

This paper studies the inventory problems with three types of fuzzy demands.(l)The newsboy problem with the random-fuzzy demand.First,this paper discusses the newsboy problem for a single item with the fuzzy-uniform and fuzzy-exponential demand distributions.Then the problem is extended to the cases with the fuzzy-free demand distribution covering a single item and multiple items with fuzzy capacity constraints.The corresponding ordering strategies are also given.(2)The problem with the price-dependent and fuzzy demand.This paper discusses two cases without or with the lead time and shortages respectively.Then the optimal ordering-price strategies are provided.(3)The optimal order time and economic lot-size problem with the linearly time-varying fuzzy demand. Under the assumption that the demand function is fuzzy, the solving method for finding the optimal order time and quantity is given in this paper.Considering the defects of modeling method in the previous models,we firstly transform the original problem into a fuzzy nonlinear programming with fuzzy constraints and then further rewrite it as a deterministic nonlinear programming according to the max-min operator.The optimal solutions are given by using the Lagrangean Multiplier's Method at last. Through some properties of the optimal solutions and some numerical examples,we analyse the impact of the demand's fuzziness on the models' solutions and the retailer's ordering strategies. Compared with this paper, the defects of the preceding modeling methods are indicated at the same time,which further shows that our method is better and more applicable than the existing ones.