Soon-Ki Heo

Production and distribution of polyvinyl chloride considering demands of warehouses

Abstract This paper deals with an integrated production and distribution of a chemical company who operates PVC plants with EDC and VCM processes. The problem is composed of two or more multi-site VCM and PVC plants, and several warehouses. There follows a case study. There are five domestic PVC plants and two are in abroad. More than 4-type PVC are produced in seven different plants and are supplied to fifteen warehouses. Eleven warehouses are domestic and the others are in abroad. The objective is defined as maximizing the net profit of the chemical company, i.e. the total expected selling price minus the production costs, the expected shipping costs and imported costs of insufficient EDC and VCM. Mixed integer linear programming (MILP) is presented to obtain an optimal production and distribution of PVC. The effectiveness of its application is illustrated with a case study. The problem is solved with CPLEX 7.0.0.

Optimal scheduling of tests for new product development

Abstract Many industries typically use screening process to discover new products. In these industries, many tasks involved in producing a new product are regulatory requirements, such as environmental and safety tests. For testing tasks in a new product development process, two kinds of mathematical models which considered scenario-based-methods and assumptions of outsourcing and retest are proposed. Throughout the application study, the proposed model allows realistic problems to be solved with reasonable computational effort.

SCHEDULING AND DESIGN FOR COST MINIMIZATION OF MULTIPURPOSE BATCH PLANT

Abstracts In this paper, multipurpose scheduling and design problems are treated simultaneously in order to minimize investment cost of plant with taking into account completion times, cycle times and equipment sizes. Usually, equipment sizes are considered as continuous variable. And processing time of task is usually assumed to be independent of batch size. However, most of manufactured equipments have their standard volume. And processing times are dependent on batch sizes. In this research, the volumes of equipments are considered as discrete variables and processing time is a function of batch size in order to apply these optimization problems to real industries.