3Sequencing Jobs through Two Work Centers – Johnson’s Rule Johnson’s Rule – a technique for minimizing makespan in a two-stage processStep 1 – List the jobs and the processing time for each activityStep 2 – Find the shortest activity processing time among the jobsIf the shortest processing time is for a 1st activity, schedule that job firstIf the shortest processing time is for 2nd activity, schedule that job lastStep 3 – Find the shortest activity processing time among the remaining jobs and schedule as in step 2 above. Repeat until all jobs are scheduled.
4Johnson’s Rule Example: Tysna’s office cleaners does the annual major cleaning of STIKOM buildings. The job requires mopping (1st activity) and waxing (2nd activity) of each building. Tysna’s wants to minimize the time it takes her crews to finish cleaning (minimize makespan) the five buildings. He needs to finish in 20 days.Activity 1(Mopping) daysActivity 2(Waxing) daysA. R. Auditorium12B. R. Serbaguna35C. Ruang Dosen4D. R. PerpustakaanE. R. Expo
5Johnson’s Rule Sequence Activity 1 (Mopping) days Activity 2 (Waxing) daysA. R. Auditorium12C. Ruang Dosen4B. R. Serbaguna35D. R. PerpustakaanE. R. Expo