| Summary: | 碩士 === 朝陽科技大學 === 工業工程與管理系碩士班 === 100 === In the production process, WIP (work in process) accounts for a major part of manufacturing cost. Hence, reducing the number of WIP is a good way to cut down production cost. It is well known that the total completion time is an effective criterion for assessing WIP cost in the production process. Also, Delivery on time and meet customer needs is an important issue for enterprises. Thus, it is important to reduce the total tardiness time of the products manufactured in the factory.
This study aim is to investigate the problem of minimizing the total completion time and minimizing the total tardiness time in preemptive open shops. Gonzalez and Sahni (1976) showed that given a job Completion Sequence (C1 ≦ C2 ≦ ... ≦ Cn), the problem can be solved by linear programming. In this study, a branch-and-bound mechanism is used to determine the best completion sequence of jobs.
This study proposes branch-and-bound methods for the problems under consideration. Upper bounds, lower bounds and dominance rules are developed to speed up search speed. Finally, the performance of the proposed methods is evaluated by a large number of randomly generated problems, including n=m and n>m two types of instances.
|
|---|
