Three essays on techniques for total costs minimization under different manufacturing/supply chain scenarios

The first essay “Cost Models for Lot Streaming in Multistage Flow Shops with Unequal Number of Sublots between Stages” proposes two total costs models. The first total costs model allows unequal number of sublots transfer between stages and shows significant reduction in the total costs of the multistage flow shop compared to the existing total costs model in literature that allows only equal number of sublots transfer between stages. The second total costs model includes the raw material’s purchasing cost (quantity discount) and the inventory holding cost in the first total costs model. Both the total costs models are formulated as a mixed integer nonlinear programming problems that are solvable with solvers. The second essay “Production and Delivery Policies with Extensions for Enhanced Supply Chain Partnerships” proposes three additional policies to the ones existing in literature with respect to Multiple Setup Multiple Delivery (MSMD) model: 1) Single Setup Single Delivery with Learning (SSSDwL), (2) Multiple Setup Multiple Delivery with allowance for unequal number of setups and deliveries (Modified MSMD), and (3) Single Setup Multiple Deliveries with Learning (SSMDwL). The first model is formulated as a nonlinear programming problem while the other two models are formulated as mixed integer nonlinear programming problems. All the problems are solvable with the solvers. Numerical illustrations reveal that the proposed models in this essay improve the results obtained with the existing models. In the third essay “Enhanced Operations Policy for a Supply Chain System with Variable-Interval Delivery and Demand Variation”, formulation of buyer’s inventory holding costs that incorporates variability in demand in multi-periods of a single supplier multiple buyer coordination system, is proposed to improve the effectiveness of the variable-interval delivery policy existing in literature in minimizing the total costs. Two solution methods are proposed to solve the formulated mixed integer nonlinear programming problem as an integer programming problem. Numerical analysis reveals improved results with the model and the methods proposed in this essay compared to the models existing in literature. Performance of our model in demand changing scenarios in the finite planned horizon is found to be satisfactory.