RESOURCES
Roger D. H. Warburton
© Kanabar /
Warburton, 2009
1
Objectives
2
Understand Constraints
Resource Constraints
Leveling
S
CHEDULES
& C
OST
E
STIMATES
Project network times are not a
schedule
until resources have
been assigned
Cost Estimates are not a
budget
until they have been time phased
3
R
ESOURCES
AND
P
RIORITIES
The Project network is not a
schedule
until resources are
assigned
Assumption:
Resources will be available in the
required amounts when needed
Assigning resources requires making
realistic judgments of availability and
project durations
4
R
ESOURCE
C
ONSTRAINT
E
XAMPLE
Plan
Play
Hire
Actors
Select
Theater
Hire
Musicians
Plan
Play
Hire
Actors
Select
Theater
Hire
Musicians
Rehearse
Re
-
hearse
5
T
YPES
OF
P
ROJECT
C
ONSTRAINTS
Technical (Logical) Constraints
Constraints related to the network sequence in which
project activities must occur
Network Diagram
Physical Constraints
Activities that cannot occur in parallel or are affected
by contractual or environmental conditions
Resource Constraints
The absence, shortage, or unique interrelationship
and interaction characteristics of resources that
require a particular sequencing of project activities.
6
C
ONSTRAINT
E
XAMPLE
•
Resource Dependency takes
precedence over the technological
dependency
•
Does not violate the technical
dependency
Plan
Play
Hire
Actors
Select
Theater
Hire
Musicians
Re
-
hearse
7
R
ESOURCE
Q
UESTIONS
Will assigned
labor
be adequate?
Will assigned
equipment
be
adequate?
Will outside contractors be needed?
Do unforeseen dependencies exist?
Is there
flexibility
in using
resources?
Is the deadline still realistic?
8
T
YPES
OF
R
ESOURCE
C
ONSTRAINTS
People
designer, engineer, welder, painter
Materials
concrete, survey data, deliveries in winter
night road work
Equipment
Earth moving equipment, copiers
Working Capital
9
C
LASSIFICATION
OF
S
CHEDULING
P
ROBLEMS
Time Constrained
A project that must be completed by
an imposed date
Resource Constrained
A project in which the level of
resources available cannot be
exceeded
10
R
ESOURCE
P
ROBLEMS
Are very complex
even for small networks
11
H
ELP
ON
S
CHEDULING
P
ROBLEMS
The priority matrix helps
determine if the project is
time or resource constrained.
Time
Performance
Cost
Constrain
O
Enhance
O
Accept
O
12
C
RITICAL
R
ESOURCE
Q
UESTION
If the CP is delayed, will resources be
added
to
get the project back on schedule?
“Yes”
Time Constrained
“No”
Resource Constrained
Time
Performance
Cost
Constrain
O
Enhance
O
Accept
O
13
T
IME
C
ONSTRAINED
P
ROJECT
A project that must be
completed by an imposed date.
Project Duration is fixed
Resources are flexible
Resources can be added to
ensure schedule is met
14
R
ESOURCE
C
ONSTRAINED
P
ROJECT
A project in which the level of
resources available cannot be
exceeded
Resources are fixed
Time is flexible
If the resources are inadequate, it is
acceptable to delay the project
15
C
ONSTRAINED
P
ROJECTS
All projects are constrained
Something will have to give
What are the priorities?
Negotiation is key
16
L
IMITING
A
SSUMPTIONS
Splitting activities is not allowed
Once an activity is started, it is carried to
completion
Activities may not be started and stopped
Resources on an activity cannot be changed
Activities with the most slack pose the least
risk
Reduction of flexibility does not increase risk
The nature of an activity (easy, complex)
doesn’t increase risk
17
E
XAMPLE
OF
T
IME
C
ONSTRAINED
B
OTANICAL
G
ARDEN
FIGURE 8.2
•
One resource: backhoes
•
Interchangeable
Slack
18
B
OTANICAL
G
ARDEN
(
CONT
’
D
)
FIGURE 8.2 (cont’d)
19
T
IME
C
ONSTRAINED
P
ROJECT
A project that must be completed by an
imposed date.
Project Duration is fixed
Resources are flexible
Resources can be added to ensure schedule is
met
Smooth the Resources
Focus on Resource Utilization
Erratic resources are difficult to manage
Level the resources
Delay non
-
criticals
Use positive slack to reduce peak demand
20
B
OTANICAL
G
ARDEN
(
CONT
’
D
)
FIGURE 8.2 (cont’d)
21
B
OTANICAL
P
ROJECT
Activities with slack:
Irrigation, Fence & Walls
Delay Fence & Walls
–
Smoother
Peak demand reduced
Resources reduced from 4 to 3
Smoother profile, easier to manage
Cost to move (people or machines)
Loss of flexibility
Reduced slack, critical activities
Most slack = least risk
22
E
XAMPLE
OF
T
IME
C
ONSTRAINED
B
OTANICAL
G
ARDEN
FIGURE 8.2
•
One resource: backhoes
•
Interchangeable
Slack
23
R
ESOURCE
-
C
ONSTRAINED
P
ROJECTS
Projects that involve resources that are limited in
quantity or by their availability.
Scheduling of activities requires the use of heuristics
(rules
-
of
-
thumb)
A modest network with a few resources has
thousands of feasible solutions
24
R
ESOURCE
A
LLOCATION
M
ETHODS
FOR
R
ESOURCE
-
C
ONSTRAINED
P
ROJECTS
Scheduling of activities requires the use of
heuristics (rules
-
of
-
thumb) that focus on:
1.
Minimum slack
2.
Smallest (least) duration
3.
Lowest activity identification number
The parallel method is the most widely used
heuristic
An iterative process that starts at the first time
period of the project and schedules period
-
by
-
period
any activities scheduled to start using the three
priority rules.
25
S
PLITTING
/M
ULTITASKING
Scheduling technique used to get a better schedule
and/or increase resource utilization
Interrupting work on an activity to employ the
resource on another activity, then returning the
resource to finish the interrupted work.
Feasible when startup and shutdown costs are
low.
Considered a major reason why projects fail to
meet schedule.
26
T
HE
I
MPACTS
OF
R
ESOURCE
-
C
ONSTRAINED
S
CHEDULING
Reduces delay but reduces flexibility.
Increases criticality of events
Increases scheduling complexity
May make traditional critical path no longer
meaningful
Can break sequence of events
May cause parallel activities to become
sequential and critical activities with slack to
become noncritical
27
C
OMPUTER
D
EMONSTRATION
OF
R
ESOURCE
-
C
ONSTRAINED
S
CHEDULING
28
L
EVELING
•
Within Slack
•
Outside Slack
•
Complicated
–
no simple solution
•
Destroys the network!
•
Now what?
29
S
UMMARY
: L
EVELING
How do we Level? After you gather your resource
requirements:
Identify resource peaks
Delay non
-
critical tasks with float
Extend schedule if needed
30
In conclusion:
Resource requirements and
availability impact your schedule. You
must leverage your skills and tools.
W
ORKSHOP
Work on the Resource Requirements Associated
with the Case Study
31
S
CHEDULE
C
OMPRESSION
32
O
BJECTIVE
Understand schedule compression techniques
Understand fast tracking and crashing concepts
within this context.
33
W
HAT
IS
D
URATION
C
OMPRESSION
Duration compression is a special case of
mathematical analysis that looks for ways to
shorten the project schedule without changing the
project scope.
PMBOK® Guide 4
th
Edition
34
W
HY
C
OMPRESSION
?
Schedule does not meet planned milestone dates.
Schedule estimate is longer than what the sponsor
desires.
Applying resource loading and leveling impacts
schedule.
Schedule slip occurs during project execution due to
things like scope creep or other circumstances.
Renegotiated project completion date
35
H
OW
?
Utilize resources, duration,
scope and additional
assets.
Use techniques such as fast
tracking and crashing.
36
F
AST
T
RACKING
Overlap activities.
37
A
B
–
3d
What are the Risks?
C
RASHING
Apply additional resources to critical path
Often results in greater project costs
Look for least expensive reduction in time
38
D
ISCUSSION
From your experience what additional skills and
assets are available for schedule compression?
39
R
EFERENCES
Kanabar & Warburton: MBA Fundamentals,
Kaplan Publishing, 2008
Gray & Larson: Project Management
–
The
Managerial Process, McGraw
-
Hill, 2008.
PMBOK: Project Management Institute, 2008
40
Enter the password to open this PDF file:
File name:
-
File size:
-
Title:
-
Author:
-
Subject:
-
Keywords:
-
Creation Date:
-
Modification Date:
-
Creator:
-
PDF Producer:
-
PDF Version:
-
Page Count:
-
Preparing document for printing…
0%
Comments 0
Log in to post a comment