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16 Part ii1
Scheduling Approaches
•
Forward scheduling
•
Scheduling ahead from some point in time.
•
Used when the question is:
•
“How long will it take to complete this job?
•
Backward scheduling
•
Scheduling backwards from some due date
•
Used when the question is:
•
“When is the latest this job can be started and still
be completed on time?”
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View Full Document 16 Part ii2
Managing Work Flows
•
Input/Output (I/O) control
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Managing work flow and queues at work centers
•
Without I/O control:
–
If demand exceeds processing capacity, a work center
overload is created
–
If work arrives more slowly than a work center can
handle, work center underutilization results
•
The goal is to strike a balance between input and output
rates in order to minimize queues and maximize
utilization
16 Part ii3
I/O Chart
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View Full Document 16 Part ii4
Assignment
•
Assignment model
–
A linear programming model for optimal assignment of
tasks and resources
•
Hungarian method
–
Method of assigning jobs by oneforone matching to
identify the lowest cost solution
16 Part ii5
Hungarian Method
1.
Row reduction: subtract the smallest number in each row from
every number in the row
a.
Enter the result in a new table
2.
Column reduction: subtract the smallest number in each column
from every number in the column
a.
Enter the result in a new table
3.
Test whether an optimum assignment can be made
a.
Determine the minimum number of lines needed to cross out all zeros
b.
If the number of lines equals the number of rows, an optimum assignment is
possible.
Go to step 6
c.
Else, go to step 4
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View Full Document 16 Part ii6
Hungarian Method (contd.)
1.
If the number of lines is less than the number of rows, modify
the table:
a.
Subtract the smallest number from every uncovered number in the table
b.
Add the smallest uncovered number to the numbers at intersections of
crossout lines
c.
Numbers crossed out but not at intersections of crossout lines carry over
unchanged to the next table
2.
Repeat steps 3 and 4 until an optimal table is obtained
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This note was uploaded on 10/02/2011 for the course MGE 429041 taught by Professor Isseyteh during the Spring '10 term at SUNY Buffalo.
 Spring '10
 IsseyTeh

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