On-line batch scheduling with real time on two parallel machines

On-line batch scheduling problem on two parallel machines is considered.Every batch has uncertain ready time.Once a machine is available,some batch is determined and the jobs in it are scheduled.Non-preemptive is permitted for processing jobs with objective to minimize makespan.An on-line batch scheduling RBLPT-algorithm is given,choose the batch with the maximum sum of processing time and then schedule by LPT-rule(the longest processing time first rule).By contradiction,the worst case is analyzed.