(a) Jack's Refrigeration Repair is under contract to repair, recondition, and/or refurbish commercial and industrial ice makers for restaurants, seafood processors and similar organisations. Jack currently has five jobs to schedule. Those jobs are shown below in the order that they arrived. He can only process one job at a time.
|
Job
|
Processing time (hrs)
|
Due (hours)
|
|
V
|
20
|
50
|
|
W
|
10
|
35
|
|
X
|
50
|
90
|
|
Y
|
15
|
35
|
|
Z
|
55
|
75
|
(i) Complete the following table.(Show your supporting calculations for each dispatching rule in separate tables)
|
Dispatching rule
|
Job Sequence
|
Average Flow Time
|
Average Number of Jobs
|
AverageLateness
|
|
FCFS
|
|
|
|
|
|
SPT
|
|
|
|
|
|
EDD
|
|
|
|
|
|
CR
|
|
|
|
|
(ii) Compare the different dispatching rules and show which dispatching rule has the best score for flow time.
(iii) Compare the different dispatching rules and show which dispatching rule has the best score for work-in-process (jobs in the system).
(iv) Compare the different dispatching rules and show which dispatching rule has the best score for lateness.
(v) What dispatching rule would you select? What is your second choice if the first choice is not available? Support your decision.