Research Information System
Thesis Type: Postgraduate
Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2023
Thesis Language: Turkish
Student: YASEMİN KİREMİTCİ
Supervisor: Gül Didem Batur Sir
Abstract:
In this study, we focused on flow shop scheduling problem, in which the jobs have release times and the machines have rate modifying activity. (RMA). As the working performance of the machines decreases over time, the processing times of the jobs tend to increase. The activities carried out in order for the machines to function in their original performance are defined as RMA. Since RMA will increase the production rate of the machines, it becomes important whether the jobs are processed on the machines before or after RMA. In order to solve the problem, a mixed integer programming model was created, which also determines the order of assignment of jobs and the HDF assignment position of machines; this model provided solutions for small-sized problems, but it was observed that it became insufficient as the size of the problem grew. For this reason, a two-stage method is proposed.With the proposed two-stage method for the solution of the problem, it is aimed to determine the order of assignment of the jobs to the machines and to determine the RMA assignment position of the machines in the two-machine flow shop environment. In the first stage, the order of assignment of the jobs to the machines was determined with an heuristic algorithm; in the second stage, a network structured shortest path based mixed integer programming model is proposed that determines the HDF assignment position order to minimize the total completion time of the jobs according to the determined job order. With the proposed model, results that offer the optimum solution in polynomial time for different problem sizes have been obtained.
Key Words : Flowshop scheduling, rate modifying activity, release time, network structure, minimizing of total completion time