In: Operations Management
Part 6. Question 10. [ Use Video-1 under Scheduling heading. ]
An organization that continuously processes proposals is addressing a large backlog due to an historical FIFO sequencing rule. You have been asked to determine a schedule that minimizes the processing time of project proposals through the editing department and revision department. The editing department identifies changes and the revision department incorporates the changes and produces a final proposal document for release. A proposal must pass through each department. Each department has personnel to service only one document at a time. The editing time is dependent on the type of proposal and the revision time is dependent on the size of the proposal. The time estimates below have been provided to you for scheduling.
Question 10. What is the minimum processing time that can be achieved for the entire project?
(A) 1274 (B) 667 (C) 633 (D) 637 (E) none of the above
Proposal # |
Editing Time (minutes) |
Revision Time (minutes) |
1 |
45 |
40 |
2 |
30 |
27 |
3 |
30 |
39 |
4 |
22 |
19 |
5 |
22 |
28 |
6 |
33 |
43 |
7 |
49 |
43 |
8 |
31 |
41 |
9 |
26 |
31 |
10 |
14 |
18 |
11 |
38 |
34 |
12 |
16 |
12 |
13 |
19 |
25 |
14 |
31 |
29 |
15 |
37 |
45 |
16 |
46 |
41 |
17 |
40 |
36 |
18 |
28 |
36 |
19 |
16 |
20 |
20 |
48 |
46 |
In order to solve the question, we have to apply the Johnson Rule to find the sequence of the job. In order to do so, we will find the least processing time job, if it belongs to Editing, then it will be placed on the left-hand side and if it belongs to revisions, then the job will be placed at the right-hand side.
So the sequence of the jobs will be as below=
10 | 19 | 13 | 5 | 9 | 18 | 3 | 8 | 6 | 15 | 20 | 7 | 16 | 1 | 17 | 11 | 14 | 2 | 4 | 12 |
The processing times of various jobs
Editing | Revision | |||
In | Out | In | Out | |
10 | 0 | 14 | 14 | 32 |
19 | 14 | 30 | 32 | 52 |
13 | 30 | 49 | 52 | 77 |
5 | 49 | 71 | 77 | 105 |
9 | 71 | 97 | 105 | 136 |
18 | 97 | 125 | 136 | 172 |
3 | 125 | 155 | 172 | 211 |
8 | 155 | 186 | 211 | 252 |
6 | 186 | 219 | 252 | 295 |
15 | 219 | 256 | 295 | 340 |
20 | 256 | 304 | 340 | 386 |
7 | 304 | 353 | 386 | 429 |
16 | 353 | 399 | 429 | 470 |
1 | 399 | 444 | 470 | 510 |
17 | 444 | 484 | 510 | 546 |
11 | 484 | 522 | 546 | 580 |
14 | 522 | 553 | 580 | 609 |
2 | 553 | 583 | 609 | 636 |
4 | 583 | 605 | 636 | 655 |
12 | 605 | 621 | 655 | 667 |
So the minimum processing time that can be achieved for the entire project= 667