Project Management COURSE 6 Resources Planning. Project Management2 Resources Estimation What resources? Quantities of resources? When needed ! Everything

Project Management

COURSE 6

Resources Planning

Project Management 2

Resources Estimation

What resources?

Quantities of resources?

When needed

! Everything estimated according with WBS


Activity Duration Estimating

Amount of work focused on the Team

Actual effort (not the duration) 40 hours work

• 1 person → 1 week• 2 persons → 2.5 days• 0.5 person → 2 weeks

Assign team members to WBS activities


Resources availability40 hours ≠ 40 hours

Full-time assignment (40 hours/week), including:

sick overhead activities (read e-mails etc) vacation attend department meeting company responsibilities

40 hours = ? hours


Resource Leveling Optimal team size Full utilization

50

Effort

Time

1 2 3 4

8 / 7.6 hours40 / 35 days22 / 18.5 weeks

daysweeksmonths


Resources Scheduling1. Time-limited scheduling

resources- unlimited, time - fixed; deadlines are very important, activities can be delayed only until their late start date

2. Resource-limited scheduling resources - limited, time - flexible; not allowed: hiring new resources, overtime, engage external teams etc.

! in practice we meet both constraint types (but in general there are not absolute limits)

Obs: resources scheduling algorithms assume that all needed resources are available


Premises

during activity resources assignment is constant to execute one activity all needed resources should be available used only one resource type one person could be used to execute any activity type


1. Time-limited scheduling

Objectives:1. To compute needed resources to be

available to execute activities;2. Execute each activity so to preserve a

constant usage of resources (when possible).

= Uniform resources consumption technique: Resources are not limited, but we will try

to optimize resources usage 6 steps


SampleOffice Installation :

(A) Prepare desks (2 pers., 12 weeks)(B) Obtain equipment (2 pers., 8 weeks)(C) Design tests (1 pers., 5 weeks)(D) Install equipment (4 pers., 10 weeks)(E) System test(3 pers., 10 weeks)(F) User training (1 pers., 5 weeks)

- D and F should be executed after A and B- E must be executed after C and D are finished


0

Step one 1: Draw activity network

Time unit: week

Act.

Pers

Time

Cond

A 2 12 -

B 2 8 -

C 1 5 -

D 4 10 A, B

E 3 10 C, D

F 1 5 A, B

0

0

10

4

20

0

30

17

412

12 522

22

632

32

A

12

C

5

B8

D

1010

E

5F


Step 2: Create activities/resources table

EMS – Earliest Moment to Start LMF – Latest Moment to Finish sorted by Float / CMTMF

Cod activitate

DescrierePers

Durată

CMDMSMarja de

timpCMTMF

Apregătire birouri

2 12 0 0 12

Bprocurare echipamente

2 8 0 4 12

Cproiectare teste

1 5 0 17 22

Dinstalare echipamente

4 10 12 0 22

E testare sistem 3 10 22 0 32

Finstruire utilizatori

1 5 12 15 32

Activity Code

DescriptionPers

Duration

EMS Float LMF

A Prepare desks 2 12 0 0 12

DInstall equipment

4 10 12 0 22

E System test 3 10 22 0 32

BAcquire equipment

2 8 0 4 12

F User training 1 5 12 15 32

C Design tests 1 5 0 17 22


Step 3: Compute needed resources

(2 12) + (2 8) + (1 5) + (4 10) + (3 10) + (1 5) = 120 man-weeks

120 / 32 = 3.75 → average 4 persons

we will compute the number of resources needed for entire project, supposing that each activity starts at the Earliest Moment of Start


Step 4: Create resource diagram

0

1

2

3

4

5

10

20

30

A

D

E

BPerson

sNumbe

r

Weeks Number

C F


Serial programming identify activities

sort activities based on float

represent graphically each activity

we obtain an initial diagram (‘automatized’)

next step: balance resource consumption (‘manually’)


Step 5: ‘Re-arrange’ activities in diagram

0

1

2

3

4

5

10

20

30

A

D

E

BPerson

sNumbe

r

Weeks Number

C FC C


‘Optimal’ schedule analysis practically, there is no deterministic algorithm to detect the optimal schedule for big projects (complex diagrams) it is not possible to ‘see’ the solution Burgess leveling procedure:

- activities sorted based on precedence- S – uniformization function:

S = xt2

where xt is th resource in time t.- cyclic algorithm of activities movements


Step 6: Change the ‘rules’

0

1

2

3

4

5

10

20

30

A

Persons

Number

Weeks Number

D

E

F

B

C

C

C CC


Time-limited resources scheduling- summary

1 Draw activity network2 Create table with activities, needed resources, duration, earliest moment to start, float, latest moment to finish. Activities are ascending sorted based on float (for equal float activities are sorted based on their latest moment to finish).3 Compute needed resources (average).4 Draw initial resource diagram, where each activity is planned at earliest moment to start, sequentially, in order obtained at previous step. In this way, critical activities are positioned at the bottom and thos having biggest float will be positioned on top.5 Re-arrange activities in diagram based on their float, so to obtain a uniform profile as possible (with the respect of the rules). 6 Change the rules to improve the profile.


2. Resource-limited scheduling Eligible activities = activities which could start if there are resources available , preserving the dependencies between activities Parallel programming: starting with the beginning of the project all eligible activities are handled in parallel

Rules: Rule no. 1 From all eligible activities we should select as the first activity that with the earliest Latest Moment of Start, than that with the shortest duration or, finally, that with the highest number of resources needed. Rule no. 2 An already started activity should continue without interruption till it is finished . Rule no. 3 If there is an eligible activity which could start, it will start. Rule no. 4 An activity is not started if the needed resources are not completely ready.


Sample

restriction: 4 persons available

Code Dependecies

Resources

Duration LMS Float LMF

A - 2 12 0 0 12

B - 2 8 4 4 12

C - 1 5 17 17 22

D A, B 4 10 12 0 22

E C, D 3 10 22 0 32

F A, B 1 5 27 15 32


1

2

3

4

5

10

20

30

A

D

F

B

MomentAvailable persons

Eligible activities sorted by LMS O

BSActivity Persons LMS

0 4

A 2 0

B 2 4

C 1 17

8 2 C 1 17

C

12 3D 4 12

F 1 27

13 3 D 4 12 17 4 D 4 12 27 4 E 3 22

E


0

1

2

3

4

5

10

20

A

D

F

B

C

E

Manual optimizations


0

1

2

3

4

5

10

20

A

F

B

C

E

Changing the ‘rules’

D

C

C CC


Resource-limited scheduling - summary

1 Draw activity network diagram and compute all moments of events occurrence.2 Build a table with activities, needed resources, durations and LMSs, used as selection criteria.3 When project starts and every time some resources are freed: · eligible activities are identified; · activities are selected to be executed, step by step, based on some decision rules. We obtain a program very close to an optimal schedule

Documents

Project Management COURSE 6 Resources Planning. Project Management2 Resources Estimation What resources? Quantities of resources? When needed ! Everything