Research On Optimal Operation Of Supply Chain In Iron And Steel Corporations

All the iron and steel corporations have to be in a competitive environment which is directed by the market and customer's demands in 20^th century. And then rapid responds are required to get corresponding plans of operations, e.g. purchase, production, logistics and so on, when market demands change. However, in our country, most iron and steel corporations can not set up an information-share platform and a rapidly responding system to market demand changes because of the decentralized management. At the same time, the rapid growth of steel production brings the rapid growth of scrap iron and scrap steel. It is really a big problem that how to remanufacture the scrap iron and scrap steel effectively when the iron and steel corporations are developing themselves into green corporations. In fact, it is really not easy for the supply chain managers to settle down the two problems mentioned.Of course, there are many scholars have been studying for years to solve the problems with control theories and optimal algorithms. And Model Predictive Control (MPC) performed well in the supply chain optimal operations, but a few problems still exist. In this thesis, the optimal operations of both forward and reverse supply chain were studied. The main contents are included below:1) In traditional optimizations of supply chain operations, because MPC cannot be used on the non-linear models, the supply chain decision-making model didn't consider the impact of purchase quantity, production quantity and logistics quantity on the unit cost of product. Then the important function of scale-effect to reduce the operation costs was ignored. Therefore, a receding-horizon algorithm integrated with Ant Colony Optimization (ACO) and MPC is presented to get optimal decisions of the supply chain with non-linear model. And the corporation's own orientation is also considered to get optimal operations with the weights on total cost, purchase cost, production cost, logistics cost and customer's satisfaction. Through simulation study with Matlab tools, the algorithm performs well on the non-linear model of supply chain operation. The simulation work showed that the total cost could be reduced with a certain degree of customer's satisfaction and smooth operations.2) There are differences between forward supply chain and reverse supply chain, especially more uncertainties in reverse supply chain. And in the reverse supply chain, the quality and quantity uncertainty of the reverse product play the most important roles in impacting on the optimal decision-making of supply chain operations. In this thesis, an optimal control solution is presented based on basic MPC principles to reduce the operation cost of reverse/remanufacturing supply chain. And some important factors which may have impacts on supply chain cost were studied in the simulation.