A single machine n job scheduling problem is examined to minimize the sum of absolute deviations of completion times from a common due date. Single and hybrid parallel genetic algorithms are developed by investigating basic operators for the application to the job sequencing problems. This thesis introduced two selection operators : Best individual selection and simple selection. By properties of scheduling problem, two hybrid technique is introduced : Due data adjustment mutation and due data adjustment reordering. The performance of these algorithms is compared with small sized example problems. The power of the hybrid parallel genetic algorithm is also illustrated with medium and large sized problems.
