Resource Oriented Scheduling

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Resource Oriented Scheduling Resource constrained scheduling should be applied

whenever there are limited resources available for a project

competition for these resources among the project activities

delays are liable to occur in such cases as activities mustwait until common resources become available.

The Resources may be: Limited Unlimited


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Resource Oriented Scheduling Limited Resources

There is a possibility that a resource is required and it is not available. If the activity is critical and it is yet to be executed than project will be delayed. The resources have to be reallocated from non-critical to critical activities. The objective is to allocate available resources to project activities in anattempt to find the shortest project schedule (min. delay) consistent with fixedresource limits.

This is called Resource Allocation Problem

In scenarios like limited staff of skilled design engineers, fixed number of

certain machines, budget restrictions this technique can be used. As aresult, activities can be scheduled only as necessary resources becomeavailable, even if the effect is to delay the project completion time


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Resource Oriented Scheduling Unlimited Resources

Resource Leveling or Smoothing Problem The objective is to reduce peak resource requirementsand smooth out period-to-period assignments, within aconstraint on project duration.


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Algorithm for Resource allocation

Step 1 : Rank all resources from the most important to the least important, and number

the resources i = 1,2,3,...,m. Set the scheduled start time for each activity to theearliest start time. Calculate early start, early finish and total float for each activity.

Step 2 : find the Halting point: when both, resources and activities for scheduling areavailable. (Start at the project beginning, so set t = 0.)

Step 3 : When several job compete for the same resources, give preference to the jobsaccording to the following rule:

1. Assign 1 st priority to the activity with least Slack, next priority to next higherslack and so on.

2. In case of a tie in float, 1st priority is assigned to the activity with highervalue of MxD i.e. the activity with max. resource requirement.

3. Further in case of a tie in MxD , higher priority is assigned to the activity withhigher value of M.

4. Further in case of a tie in M , higher priority is assigned to the activity withlower tail event.

A Resource-Oriented Scheduling Procedure


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Algorithm for Resource allocation

Step 4 : Update early start, early finish and total floats of activities affected by thefloating out of activity after resource assignment.

Step 5 : If all the activities are assigned the resources then stop otherwise goto Step 2.

A Resource-Oriented Scheduling Procedure


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ExampleActivity Dur (D) M(Manpower) MxD

12 5 1 5

13 3 1 3

15 2 1 2

23 Dummy

26 4 1 4

34 5 1 5

47 5 1 5

56 3 1 3 67 3 1 3

30

Manpoweravailable = 2(M1, M2)


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1

3 4

2 6 7

5

5

5

5

4 3

2 3

0,0

5,5

2,9

9,12

10,10

5,5 15,15

Solution - Network


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30

3 1 3 67

3 1 3 56

5 1 5 47

5 1 5 34 4 1 4 26

Dummy 23

2 1 2 15

3 1 3 13

5 1 5 12

12

9

10

5 8

5

7

2

0

LS MxD M(Manpower)

Dur (D) Activity

9

2

10

5 5

5

0

0

0

ES

3

7

0

0 3

0

7

2

0

TotalFloat

15

12

15

10 12

5

9

5

5

LF

12

5

15

10 9

5

2

3

5

EF

1

3 4

2 6 7

5

5

5

5

4 3

2 3

0,0

5,5

2,9

9,12

10,10

5,5 15,15


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Example 2Activity Dur (D) M(Manpower) MxD

12 10 1 10

13 6 2 12

15 5 3 15

23 Dummy

26 8 1 8

34 10 2 20

47 10 3 30

56 7 1 7 67 5 2 10

112

Manpoweravailable = 4(M1, M2,M3,

M4)


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1

3 4

2 6 7

5

10

10

10

8 5

5 7

0,0

10,10

5,18

18,25

20,20

10,10 30,30

Solution - Network


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30

10 2 5 67

7 1 7 56

30 3 10 47

20 2 10 34 8 1 8 26

Dummy 23

15 3 5 15

12 2 6 13

10 1 10 12

25

18

20

10 17

10

13

4

0

LS MxD M(Manpower)

Dur (D) Activity

18

5

20

10 10

10

0

0

0

ES

7

13

0

0 7

0

13

4

0

TotalFloat

30

25

30

20 25

10

18

10

10

LF

23

12

30

20 18

10

5

6

10

EF

1

3 4

2 6 7

5

10

10

10

8 5

5 7

0,0

10,10

5,18

18,25

20,20

10,10 30,30

0 10 18 23 33


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10 M1, M4 1 7 67 M1, M4 18

Priority TotalFloat

0 1 . 30 47

M2, M3 21

. 20

8

Dummy

0

7

1

2

34

M1 26

23 M1 10

7 1 M2,M3, M415 15 M2,M3,M4

6

Allocation ofresources

MxD Activity whichcan be scheduled

AvailableResources

Halt Time

13 4

0

3 2

1

-15 15 M2, M3 12 13

M1 10 12 M1,M2,M3,M4

0

-3 1 M1, M2,M330 47 M1, M2,M3, M423

7 2 7 M4 56

M2,M3,M4

11 20 -1 1 34 M2, M3

M1 12 26 67 47

M2 13 15 34 47 M3 13 15 34 47 M4 15 56 67

0 6 11 18 23

0 10 18

21

23 33

33

0 10 18 23 33


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10 M1, M4 1 7 67 M1, M4 18

Priority TotalFloat

0 1 . 30 47

M2, M3 21

. 20

8

Dummy

0

7

1

2

34

M1 26

23 M1 10

Allocation ofresources

MxD Activity whichcan be scheduled

AvailableResources

Halt Time

13 4

0

3 2

1

-15 15 M2, M3 12 13

M1 10 12 M1,M2,M3,M4

0

-3 1 M1 M2 M33047M1, M2,M3, M423

7 2 7 M4 56

M2,M3,M4

11 20 -1 1 34 M2, M3

56

34

34

47

47

47

67

67 26

13

13

12

M4

M3

M2

M1

7 1 M2,M3, M415 15 M2,M3,M4

6

15

15

15

0 6 11 18 23

0 10 18

21

23 33

33

30

10 2 5 67

7 1 7 56

30 3 10 47 20 2 10 34

8 1 8 26

Dummy 23

15 3 5 15

12 2 6 13

10 1 10 12

25

18

20 10

17

10

13

4

0

LS MxD M(Manpower)

Dur (D) Activity

18

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20 10

10

10

0/6

0

0

ES

7

13/7

0 0

7

0

13/7

4

0

TotalFloat

30

25

30 20

25

10

18

10

10

LF

23

12/18

30 20

18

10

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6

10

EF

30

10 2 5 67

7 1 7 56

30 3 10 47

20 2 10 34

8 1 8 26

Dummy 23

15 3 5 15

12 2 6 13

10 1 10 12

25

18

20

10

17

10

13

4

0

LS MxD M(Manpower)

Dur (D) Activity

18

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20/21

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10

10

0/6

0

0

ES

7

13/7

0/-1

0/-1

7

0

13/7

4

0

TotalFloat

30

25

30

20

25

10

18

10

10

LF

23

12/18

30/31

20/21

18

10

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6

10

EF

Resource Oriented Scheduling

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