p resources

1

Resources Management

04/11/2006 Emad Elbeltagi 2


What a resource?

Any thing that is used by an activity to get the work done,

such as: Material, Equipment, Labor, Money, …..

Resources can be classified as:

Consumable (Money, Material,……)

Non Consumable (Labor, Equipment,…)

2


Resources ManagementDuration-Driven Schedule

All CPM scheduling techniques are duration driven schedules

Basic units: activities, durations, relationships

Assumes resources are available whenever needed

Also, resources can be classified as:

Key or constrained resources (Skilled labor, Equipment,……)

Secondary or non-constrained resources (Labor, …)

General resources, used by all activities



Resource aggregation or Resource loading

The summation, on a period-by-period basis, of the

resources required to complete all activities based on the

schedule carried out in the previous stage

The results are usually shown graphically as a histogram

A separate graph will be required for each resource

3


Shown in the histogram

23252

ABCDE

Resources (units/week)Duration (Weeks)Activity

Resources ManagementResource aggregation or Resource loading

Consider the following activities

Resource limit = 10 units /week



Resource limit

4




Resources ManagementProblems Associated with Resource

Resource Fluctuation (Resource leveling)

Resource Over allocation (Resource Scheduling)

Resource

TimeResource profile with high resource fluctuation (High hiring and firing)

Resource limit

Resource

TimeLess hiring and firing (More stable work conditions)

5


Resources ManagementMethods for Resolving Resource conflicts (Problems)

Optimization Models (Utilize optimization techniques):

Linear programming models

Advantages: Provide optimum solution

Limitations: Cannot be applied to large problems

Heuristic Models (Utilize rule of thumb based on experience):

Heuristic or rules of thumb

Advantages: Can be applied to large problems

Limitations: Do not provide optimum solution


Resources ManagementResource Leveling (Smoothing)Unconstrained resource scheduling (Constrained time)

Resource Leveling

Resource unconstrained (No limits on resources)

Time (Project completion) constrained; project duration not

be delayed

Reduce the difference between the peaks and the valleys

Average resource usage

The objective is to smooth the use of the resources to

avoid the resource fluctuation

6


Resources ManagementResource Leveling (Smoothing)



Minimum Moment Algorithm = ∑ Yi * Yi /2

7



Heuristic Method Procedure

Prepare a complete activity schedule

Draw a bar chart based on ES timings

Draw the FF as dashed line beside the upper side of the bar

and the TF beside the lower side

Put the resource usage in each bar of the related activity

Critical activities to be drawn first (do not move them)

Aggregate the resources in each time period



Procedure

Calculate the total usage of resources = ∑ unit period usage

Calculate the average resource usage = ∑ usage / utilization

period

Shift non-critical activities within their FF first, then their TF to

decrease the peaks and raise the valleys

Revise the activities float

Aggregate the resources in each time period

8


Resources ManagementResource Leveling (Example)

Example

-11122344

5, 66, 72, 8

2, 8, 910, 11, 12, 13

Predecessors

00221231042240

02532666427322

ABCDEFGHIJKLMN

Resource (units/week)Duration (Weeks)Activity



A (0)0 0

0 0

F (6)5 11

2 8B (2)

3 5

0 2

D (3)6 9

0 3

I (4)12 16

3 7

G (6)5 11

5 11

H (6)9 15

3 9

M (2)16 18

9 11

J (2)16 18

8 10

L (3)15 18

9 12

K (7)11 18

11 18N (2)

18 20

18 20C (5)

0 5

0 5

E (2)14 16

2 4

9



00004000280670

FF

025348

1197

1018121120

EF

0306

12306980670

0000225338

1199

18

ABCDEFGHIJKLMN

TFESActivity



0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20C, 2 G, 3 K, 2 N, 0

B, 0D, 2

E, 1F, 2

H, 1I, 0

J, 4L, 2

M, 4

4 ∑= 904 7 6 5 6 6 6 8 13 9 4 2 2 2 2 2 2

10



01234567891011121314

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20



0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20C, 2 G, 3 K, 2 N, 0

B, 0D, 2

E, 1F, 2

H, 1I, 0

J, 4L, 2

M, 4

∑= 90M (7 days) -4 -4 +4 +4

4 4 7 6 5 6 6 6 8 9 5 4 2 2 2 2 6 6J (6 days) -4 -4 +4 +4

4 4 7 6 5 6 6 6 4 5 5 4 2 2 6 6 6 6L (2 days) -2 -2 +2 +2

4 4 7 6 5 6 6 6 8 1 3 9 4 2 2 2 2 2 2

4 4 7 6 5 6 6 6 4 3 3 4 4 4 6 6 6 6

11



0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20C, 2 G, 3 K, 2 N, 0

B, 0D, 2

E, 1F, 2

H, 1I, 0

J, 4L, 2

M, 4

∑= 90E (10 days) -1 -1 +1 +1

4 4 6 5 5 6 6 6 4 3 3 4 5 5 6 6 6 6H (2 days) -1 -1 +1 +1

4 4 6 4 4 6 6 6 4 4 4 4 5 5 6 6 6 6F (1 days) -2 +2

4 4 7 6 5 6 6 6 4 3 3 4 4 4 6 6 6 6

4 4 4 4 4 6 6 6 6 4 4 4 5 5 6 6 6 6



0

1

2

3

4

5

6

7

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

12


Resources ManagementResource SchedulingConstrained resource scheduling (Unconstrained time)

Resource Scheduling

Constrained Resources

Unconstrained project completion; project time may be delayed

Reduce the resource usage to be less than the resource availability

The objective is to meet the resources limits


Resources ManagementResource Scheduling

R 2 A2 B1 C1 D2 E

R2 A2 B1 C1 D2 E

Resource limit = 2

2 2 2 2 1 1 2 2 2 2

2 2 4 4 1 1 2 2

13



Is there is a way to prioritize activities

That compete for the limited resources

so that the net project delay is

minimized?



Resource Scheduling Rules of Thumb

Many rules have been experimented with

Least TF were found to be most effective

Least LS has the same effect as the least TF and doesn’t

require network recalculations

In case of a tie use least TF

14



Procedure

Prepare a complete activity schedule

Aggregate the daily resource demand

If demand greater than available then determine activities

compete for resources

Prioritize these activities based on their LS

Allocate resources to some activities and delay the others

Put your solution in table format


Resources ManagementResource Scheduling (Example)

01011100110

R2 ≤1R1≤8

---ADBBF

E, HC

G, J

Predecessors

36404042452

64284

1016866

10

ABCDEFGHIJK

Resource (units/week)Duration (Weeks)Activity

15


Resources ManagementResource Scheduling (Example)

Start (0)0 0

0 0

F (10)8 18

6 16

B (6)0 6

0 6

I (6)26 32

24 30

G (16)6 22

6 22

J (6)16 22

2 8

A (4)10 14

0 4

H (8)18 26

16 24

E (4)22 26

12 16

K (10)22 32

22 32End (0)32 32

32 32

C (2)14 16

0 2

D (8)14 22

4 12

3, 0

4, 0 5, 1

4, 06, 1

0, 1

0, 1 4, 1

2, 0 4, 1

2, 0

Finish TimeR2 ≤1R1≤8

DecisionEarliest LSDuration

ResourcesEligible Activities

Current Time

0 BAC

6 1 6 03 0 4 104 0 2 14

StartDelayDelay

6--

6 GFAC

4 0 16 60 1 10 83 0 4 104 0 2 14

StartStartStartDelay

221610-

10 GFCD

4 0 16 -0 1 10 -4 0 2 140 1 8 14

ContinueContinue

2216

StartDelay

12-

12 GFDJ

4 0 16 -0 1 10 -0 1 8 145 0 6 16

ContinueContinue

2216

DelayDelay

--

16 GDJH

4 0 16 -0 1 8 145 1 6 162 0 8 18

Continue 22StartDelayStart

24-

24

16

Finish TimeR2 ≤1R1≤8

DecisionEarliest LSDuration

ResourcesEligible Activities

Current Time

22 DHJ

0 1 8 -2 0 8 -5 1 6 16

2424

24 JE

5 1 6 144 1 4 22

30 StartStart

3440

Continue

40Start

ContinueContinueDelay -

StartDelay

30-

EK

4 1 4 222 0 10 22

34 KI

2 0 10 -2 0 6 26

40

p resources

Documents

resources managementresource leveling

activities based

resource usage

resource loading

constrained resources

resource

resources

activities