The major theme of this thesis is the mathematical optimization modelling of the flexible job shop scheduling problem. This problem is present in the so-called multitask cell—a production cell at GKN Aerospace’s facility located in Trollhättan, Sweden—which has served as a case study during the work with this thesis. The thesis consists of two parts, of which the first considers the major theme...

In this paper, we propose 260 scheduling problems whose size is greater than that of the rare examples published. Such sizes correspond to real dimensions of industrial problems. The types of problems that we propose are : the permutation flow shop, the job shop and the open shop scheduling problems. We restrict us to basic problems : the processing times are fixed, there are neither set-up tim...

In manufacturing area, the most difficult problems related to the time-efficiency frequently occur if the jobs to be scheduled are heterogeneous, if there are alternative routes on the machines for the jobs and multiple objectives are imposed. This framework, named Multi-Objective Flexible Job Shop Scheduling Problems (MOFJSSP), has been formalized, modeled and studied in the last decades from ...

In the stochastic online scheduling environment, jobs with unknown release times and weights arrive over time. Upon arrival, the information on the weight of the job is revealed but the processing requirement remains unknown until the job is finished. With the objective of minimizing the total weighted completion time, various asymptotically optimal algorithms have been proposed for the online ...

Flexibility in job shop scheduling is a main problem that has been considered by many of researchers in recent years.So Scheduling for the flexible job shop is very important in the field of production management and combinatorial optimization. However, it is quite difficult to achieve an optimal solution to this problem in medium and actual size problems with traditional optimization approache...

The problem of finding good solutions to scheduling problems is very important to real manufacturing systems, since the production rate and production costs are very dependent on the schedules used for controlling the work in the system. Most research in scheduling focuses on optimisation of static problems, where all problem data are known before scheduling starts. However many real world opti...

A train scheduling problem in a single-track railway can be modeled as a job-shop scheduling problem. We use a mixed graph model for such a job-shop problem with appropriate criteria. There are several performance evaluations for a train schedule. Optimizing a train schedule subtends minimizing total tardiness of the trains, minimizing the sum of train transit times, minimizing the makespan for...

The n-job, m-machine flow shop scheduling problem is one of the most general job scheduling problems. This study deals with the multi objective optimization with the criteria of makespan minimization and minimization of total weighted flow time for the flow shop scheduling problem. The n-job mmachine problem is known to be NP hard problem, several meta heuristics have been applied so far in the...

The Job Shop Scheduling Problem (JSSP) is a well known practical planning problem in the manufacturing sector. We have considered the JSSP with an objective of minimizing makespan. In this paper, we develop a three-stage hybrid approach called JSFMA to solve the JSSP. In JSFMA, considering a method similar to Shuffled Frog Leaping algorithm we divide the population in several sub populations an...