Job sequencing for unrelated parallel machines with fuzzy processing time and fuzzy duedate

Focusing upon job sequencing in fuzzy production environment, the fuzzy scheduling model and its algorithm are proposed for unrelated parallel machines in this study. Considering uncertain jobs´ processing times and due dates, in light of the possibility and necessity measures in fuzzy theory, the tardiness credibility index of job is proposed to estimate the possibility of job´s tardiness. The mixed integer programming model of unrelated parallel machines is constructed for average credibility of job´s tardiness. A novel hybrid fuzzy genetic algorithm is developed to tackle the model. Finally, a case study is given to demonstrate the effectiveness of the proposed algorithm.