Batch scheduling in supply chains

Supply chain management is a major issue in many industries as firms realize the importance of creating an integrated relationship with their suppliers and customers. In many manufacturing organizations minimizing the total cost of inventory holding and delivery plays a major role in production scheduling. Inventory holding cost is proportional to the flow time of jobs at the shop. Therefore, we study single machine batch scheduling problems to minimize the sum of weighted flow time and the delivery cost in supply chains.; It has been proven that many single machine batch scheduling problems even at the supplier level and the manufacturer level are hard problems to be solved. Therefore, batch scheduling problems for supplier-manufacturer coordination are even harder. Hence, heuristic algorithms may be developed to solve such problems. A good heuristic can be developed only when the specific properties of the given problem are analyzed thoroughly. Since there are many problems at the supplier level and manufacturer level not yet solved, we study single machine scheduling problems under different conditions at the supplier and manufacturer. Then we study batch scheduling problems in a supplier-manufacturer system.; We first study some polynomially solvable problems at the supplier and at the manufacturer. Batch scheduling problems at the supplier when jobs have arbitrary processing times and arbitrary weights are intractable. We provide a 2-approximation algorithm for this problem. The performance of this 2-approximation algorithm shows that it provides close to optimal solutions for practical situations. Batch scheduling problems at the manufacturer of multi-product case is intractable even if the weights are identical. We provide a 2-approximation algorithm for this problem and a hybrid meta-heuristic algorithm for the arbitrary weight case. We develop an algorithm for the lower bound of this problem and compare the result of the heuristic algorithm with that of the lower bound solution.; Then some batch scheduling problems at the manufacturer in a customer centric supply chain are analysed and dynamic programming algorithms are developed to solve these problems optimally. Finally batch scheduling with supplier manufacturer coordination is studied and there again dynamic programming algorithms are developed to solve the hatch scheduling problems of given job sequence under two different conditions.