The following jobs are waiting to be processed at Keah-Lan’s machine center Job
ID: 367247 • Letter: T
Question
The following jobs are waiting to be processed at Keah-Lan’s machine center
Job
Date Order Received
Processing Days Needed
Date Order Due, End of Day __
A
110
20
180
B
120
30
200
C
122
10
175
D
125
16
230
E
130
18
210
The jobs are listed in the order in which they were received. Suppose that it is now the start of day 151, so day 151 is a work day on the planning calendar and none of the above jobs have been started yet. There are no other jobs waiting or in the system at this time. All the resources required for each job are on hand. Once a job is started, it will not be stopped until it is completed. Each job is scheduled to be worked on the machine center’s only machine.
For the CR and LPT, what is the sequence of these two rules based on each of the following criterion? • Average flow time measured from now (start of day 151) • Average lateness with no credit for being early • Average days early with no penalty for being late
Job
Date Order Received
Processing Days Needed
Date Order Due, End of Day __
A
110
20
180
B
120
30
200
C
122
10
175
D
125
16
230
E
130
18
210
Explanation / Answer
CR:
LPT
Current day 151 Job Date Order Received Processing Days Needed Date Order Due, End of Day __ Days left Critical ratio Priority A 110 20 180 29 1.45 1 B 120 30 200 49 1.633333333 2 C 122 10 175 24 2.4 3 D 125 16 230 79 4.9375 5 E 130 18 210 59 3.277777778 4Related Questions
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