Existing methods of local search mostly focus on how to reach optimal solution.However,in some emergency situations,search time is the hard constraint for job shop scheduling problem while optimal solution is not nece...Existing methods of local search mostly focus on how to reach optimal solution.However,in some emergency situations,search time is the hard constraint for job shop scheduling problem while optimal solution is not necessary.In this situation,the existing method of local search is not fast enough.This paper presents an emergency local search(ELS) approach which can reach feasible and nearly optimal solution in limited search time.The ELS approach is desirable for the aforementioned emergency situations where search time is limited and a nearly optimal solution is sufficient,which consists of three phases.Firstly,in order to reach a feasible and nearly optimal solution,infeasible solutions are repaired and a repair technique named group repair is proposed.Secondly,in order to save time,the amount of local search moves need to be reduced and this is achieved by a quickly search method named critical path search(CPS).Finally,CPS sometimes stops at a solution far from the optimal one.In order to jump out the search dilemma of CPS,a jump technique based on critical part is used to improve CPS.Furthermore,the schedule system based on ELS has been developed and experiments based on this system completed on the computer of Intel Pentium(R) 2.93 GHz.The experimental result shows that the optimal solutions of small scale instances are reached in 2 s,and the nearly optimal solutions of large scale instances are reached in 4 s.The proposed ELS approach can stably reach nearly optimal solutions with manageable search time,and can be applied on some emergency situations.展开更多
The strong non-deterministic polynomial-hard( NP-hard)character of job shop scheduling problem( JSSP) has been acknowledged widely and it becomes stronger when attaches the nowait constraint,which widely exists in man...The strong non-deterministic polynomial-hard( NP-hard)character of job shop scheduling problem( JSSP) has been acknowledged widely and it becomes stronger when attaches the nowait constraint,which widely exists in many production processes,such as chemistry process, metallurgical process. However,compared with the massive research on traditional job shop problem,little attention has been paid on the no-wait constraint.Therefore,in this paper, we have dealt with this problem by decomposing it into two sub-problems, the timetabling and sequencing problems,in traditional frame work. A new efficient combined non-order timetabling method,coordinated with objective of total tardiness,is proposed for the timetabling problems. As for the sequencing one,we have presented a modified complete local search with memory combined by crossover operator and distance counting. The entire algorithm was tested on well-known benchmark problems and compared with several existing algorithms.Computational experiments showed that our proposed algorithm performed both effectively and efficiently.展开更多
The aim of the study was to explore the relationship between college graduates’dual self-consciousness,job search clarity and perceived stress,and reveal the mediating role of perceived stress between dual self-consc...The aim of the study was to explore the relationship between college graduates’dual self-consciousness,job search clarity and perceived stress,and reveal the mediating role of perceived stress between dual self-consciousness and job search clarity.In this study,467 college graduates were investigated using the Dual Self-Consciousness Scale,Job Search Clarity Scale,and Perceived Stress Scale.After controlling for gender,age,and region,the results revealed that:(1)private self-consciousness has a significant positive predictive effect on job search clarity;(2)perceived stress has a significant negative predictive effect on job search clarity;(3)perceived stress plays partial mediation effects between private self-consciousness and job search clarity;(4)perceived stress plays complete mediation effects between public self-consciousness and job search clarity;(5)perceived stress has suppressing effects between public self-consciousness and job search clarity.展开更多
An effective heuristic algorithm for solving the minimum makespan problem of job shop scheduling is presented. With a given feasible solution as a start point, we use Taboo Search technique to get a schedule for each ...An effective heuristic algorithm for solving the minimum makespan problem of job shop scheduling is presented. With a given feasible solution as a start point, we use Taboo Search technique to get a schedule for each neighbor of all its neighbors, and select the best one of the schedules as the new start point. We repeat the procedure, unless the new start point is not better than the proceeding one. To make sure of better results, we introduce reverse technique to the algorithm as well. The computational experiments of the 45 standard instances show that our algorithm yields better results than TSAB algorithm.展开更多
A new local search method with hybrid neighborhood for Job shop scheduling problem is developed. The proposed hybrid neighborhood is not only efficient in local search, but also can help overcome entrapments while sea...A new local search method with hybrid neighborhood for Job shop scheduling problem is developed. The proposed hybrid neighborhood is not only efficient in local search, but also can help overcome entrapments while search procedure get trapped at local optima and carry the search to areas of the feasible set with better prospect. New strategies used for breaking out of entrapments are presented and they are helpful for the procedure to improve local optima. A performance comparison of the proposed method with some best-performing algorithms on all 10-job, 10-machine benchmark problems and the other two problems generated by Fisher and Thompson (ie., FT6 and FT20)is made. The experiment results show the better optimal performance of the proposed algorithm.展开更多
基金supported by National Natural Science Foundation of China(Grant No.61004109)Fundamental Research Funds for the Central Universities of China(Grant No.FRF-TP-12-071A)
文摘Existing methods of local search mostly focus on how to reach optimal solution.However,in some emergency situations,search time is the hard constraint for job shop scheduling problem while optimal solution is not necessary.In this situation,the existing method of local search is not fast enough.This paper presents an emergency local search(ELS) approach which can reach feasible and nearly optimal solution in limited search time.The ELS approach is desirable for the aforementioned emergency situations where search time is limited and a nearly optimal solution is sufficient,which consists of three phases.Firstly,in order to reach a feasible and nearly optimal solution,infeasible solutions are repaired and a repair technique named group repair is proposed.Secondly,in order to save time,the amount of local search moves need to be reduced and this is achieved by a quickly search method named critical path search(CPS).Finally,CPS sometimes stops at a solution far from the optimal one.In order to jump out the search dilemma of CPS,a jump technique based on critical part is used to improve CPS.Furthermore,the schedule system based on ELS has been developed and experiments based on this system completed on the computer of Intel Pentium(R) 2.93 GHz.The experimental result shows that the optimal solutions of small scale instances are reached in 2 s,and the nearly optimal solutions of large scale instances are reached in 4 s.The proposed ELS approach can stably reach nearly optimal solutions with manageable search time,and can be applied on some emergency situations.
基金National Natural Science Foundations of China(Nos.61174040,61104178)Shanghai Commission of Science and Technology,China(No.12JC1403400)the Fundamental Research Funds for the Central Universities,China
文摘The strong non-deterministic polynomial-hard( NP-hard)character of job shop scheduling problem( JSSP) has been acknowledged widely and it becomes stronger when attaches the nowait constraint,which widely exists in many production processes,such as chemistry process, metallurgical process. However,compared with the massive research on traditional job shop problem,little attention has been paid on the no-wait constraint.Therefore,in this paper, we have dealt with this problem by decomposing it into two sub-problems, the timetabling and sequencing problems,in traditional frame work. A new efficient combined non-order timetabling method,coordinated with objective of total tardiness,is proposed for the timetabling problems. As for the sequencing one,we have presented a modified complete local search with memory combined by crossover operator and distance counting. The entire algorithm was tested on well-known benchmark problems and compared with several existing algorithms.Computational experiments showed that our proposed algorithm performed both effectively and efficiently.
基金supported by the academic requirements for the National Education Science Planning Project of China under Grant No.BBA210041.
文摘The aim of the study was to explore the relationship between college graduates’dual self-consciousness,job search clarity and perceived stress,and reveal the mediating role of perceived stress between dual self-consciousness and job search clarity.In this study,467 college graduates were investigated using the Dual Self-Consciousness Scale,Job Search Clarity Scale,and Perceived Stress Scale.After controlling for gender,age,and region,the results revealed that:(1)private self-consciousness has a significant positive predictive effect on job search clarity;(2)perceived stress has a significant negative predictive effect on job search clarity;(3)perceived stress plays partial mediation effects between private self-consciousness and job search clarity;(4)perceived stress plays complete mediation effects between public self-consciousness and job search clarity;(5)perceived stress has suppressing effects between public self-consciousness and job search clarity.
基金Supported bythe National Basic Research Programof China (973 Pragram G1998030600)
文摘An effective heuristic algorithm for solving the minimum makespan problem of job shop scheduling is presented. With a given feasible solution as a start point, we use Taboo Search technique to get a schedule for each neighbor of all its neighbors, and select the best one of the schedules as the new start point. We repeat the procedure, unless the new start point is not better than the proceeding one. To make sure of better results, we introduce reverse technique to the algorithm as well. The computational experiments of the 45 standard instances show that our algorithm yields better results than TSAB algorithm.
基金TheNationalGrandFundamentalResearch973ProgramofChina (No .G19980 30 6 0 0 )
文摘A new local search method with hybrid neighborhood for Job shop scheduling problem is developed. The proposed hybrid neighborhood is not only efficient in local search, but also can help overcome entrapments while search procedure get trapped at local optima and carry the search to areas of the feasible set with better prospect. New strategies used for breaking out of entrapments are presented and they are helpful for the procedure to improve local optima. A performance comparison of the proposed method with some best-performing algorithms on all 10-job, 10-machine benchmark problems and the other two problems generated by Fisher and Thompson (ie., FT6 and FT20)is made. The experiment results show the better optimal performance of the proposed algorithm.
