An integrated supply chain model with fuzzy demand and its algorithm

An integrated supply chain model with fuzzy demand is built in this paper. The model is converted into a bilevel programming, in which the upper level programming is an uncertain programming with fuzzy demand, and the lower level programming is a certain programming with the specified parameters passed from the upper level. A genetic algorithm combined with fuzzy simulation technology is proposed to find the optimal decisions in the upper level programming. In the lower level, under the given decision from the upper level, a simulated annealing algorithm is provided to obtain the optimal values which are then sent back to the upper level. Through the evolutionary processes such as crossover and mutation operations, the optimal solutions to achieve the minimum system cost can be found. Lastly numerical examples are given to show the validity of the algorithm.