Improved Genetic Algorithm Based On Preference Encoding For JOB Shop Scheduling Optimization Problem

Job-shop scheduling problem(JSP) is one of the important parts in the productionmanagement, a effective solution method not only can help to improve productionefficiency, reduce production costs, but also can accelerate the company’s responsespeed to the market so as to improve the economic efficiency and the Marketcompetitiveness of the company. Because of job-shop is a typically NP-hard problem,so that traditional optimization algorithms is difficult to get the optimal solution, so thispaper is based on the previous studies, adopted the most widely used genetic algorithmas solution method, and traditional genetic algorithm has be improved to promote thesolution efficiency.We designed a new encoding method based on operation order matrix, and basedon operation order matrix encoding method, a JSP mathematical model is established, inwhich the makespan is taken as objective function, and designed new crossover andmutation methods, and the computation results demonstrate the improved geneticalgorithm is efficient.We established an optimization model of flexible job shop scheduling problem, anddesign a genetic algorithm which is based on dual coding method to deal with it, anddesign new dual coding method, decoding method, crossover and mutilation method,for different optimization objectives we computer different examples.In this paper, we established an optimization model of multi-objective flexible jobshop scheduling problem, with makespan maximal workload, total workload and totaltardiness as objective function, a new non-dominated sorting method is introduced,which can get the Pareto optimal solutions quickly and correctly by dividing the wholepopulation into three parts, which improved the classification efficiency.Analysis the time factors of the JSP, and consideration of the time of job routingbetween machines, which made the JSP model more closely to actual production.On the basis of the theoretical study, we design a job shop scheduling optimizationsoftware by VC++. Optimization examples show the effectiveness of the algorithm.