Page 217 - DCOM303_DMGT504_OPERATION_RESEARCH

Operations Research

Notes  Sequencing problems can be considered with situations where there is a selection of an
appropriate order for a series of different jobs to be done on a finite number of service
facilities.
 Sequencing helps to resolve problems when multiple jobs are to be done on finite facilities.

10.7 Keywords

Idle Time: Time for which the machine does not have any job to process.

No passing Rule: The condition to be satisfied in which the order of jobs are to be processed on
given machines.
Processing Order: Sequence in which the machines are required for completing the job.

Processing Time: Time required by a job on each machine.
10.8 Review Questions

1. What is a sequencing problem?
2. Define the various terminologies used in sequencing.
3. What are the assumptions made in solving sequencing problems ?
4. Explain the method of processing ‘n’ jobs through two machines.

5. What is the ‘no passing rule’ in sequencing?
6. Define the terms (i) Total elapsed time, and (ii) Idle time.
7. What are the advantages of sequencing?

8. Find the optimal sequence that minimizes the total elapsed time required to complete the
following jobs.

Job 1 2 3 4 5 6
Machine 1 4 6 6 10 5 8
Machine 2 6 7 9 2 4 11

9. A plastic folder manufacturer has two machines – cutting machine and sealing machine.
He produces five varieties of folders. Due to design and size, the time taken for cutting and
sealing differs from one folder to another. The time consumed for each operation is given
in the table. The manufacturer wants to determine the order in which the folders should be
processed to minimize the total time required to process all the folders.
Folder Type 1 2 3 4 5
Cutting 15 30 25 10 15
Sealing 10 9 7 3 10

10. An insurance company receives three types of policy application bundles daily from its
head office for data entry and filing. The average time taken for each type for these two
operations is given in the following table:
Policy 1 2 3
Data Entry 90 120 80
Filing 140 110 100

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