Resource analysis 1
Project management
(seminar)
Introduction
• Sometimes one or more resources (especially
skilled workers) are equally or more
important than time. According to priority,
there are:
– time-limited and
– resource-limited
projects. Priority can change over time but it is
not wise to have double priorities.
• Basic tools came from production engineering:
loading (resource allocation)
Resources
• Definition: anything that is scarce and required for any
activity in the project. Resources are constraints for the
project.
• Resources can be:
– Non-storable: has to be renewed for each period
e.g. work
– Storable: depleted only by usage (remains available if not used)
e.g. money
• The most common resource typology, the 4Ms:
–
–
–
–
–
Men
Machines
Money (cost)
Material
Other
Loading (resource allocation)
• The assignment of work to an worker, machine
or unit (generally: to a workstation) in time.
• A workstation can be:
– underloaded (load < capacity)
– fully loaded (load = capacity)
– overloaded (load > capacity)
• Fully loading is nearly impossible to reach except
in flow production.
• Underloading is the most common, because it
respects time. Overloading leads to be late.
Defining resources for projects
• SOW
• WBS
• Task list
– Resource needs given in resource-hours
(e.g. man-hour, machine-hour)
– Two forms of resource specification:
• Rate-constant (can be changed to a constant
function/patter): constant usage rate defines the
duration, too
• Total constant: to finish the activity
What to do with non-linear
duration-resource functions?
• Use a computer
• Focus on quasi-linear parts of the functions
Capacity
• Be realistic:
– Usual efficiency
– Estimated absenteeism, sickness, holidays
– Existing commitments
– Ancillary tasks and their resource needs
– Any additional constraints (like methodology) and
limitations (like work contracts)
• Also calculate with the possibilities
(cost, time, trade-offs) to increase capacity
Defining resources for projects 2
•
•
•
•
•
•
SOW
WBS
Task list
Logical connections (PNT)
Gantt chart and histogram
Levelling
Using the bar chart
• Set up and analyse the network
– Assign the resource data to the activities
• Draw the Gantt chart
– Aggregate each resource time period by time
period throughout the total project
• Cumulating (Summation or S Curve):
• Use levelling the load for optimization
Network with single resource data
0
2
0
0
0
0
0
0
0
0
2
a
(1)
2
2
0
0
5
5
5
b
(4)
5
10
c
(3)
8
10
3
5
0
10
0
2
START (0)
0
2
0
5
3
7
d
(2)
5
10
10
10
0
13
e
(1)
3
13
0
13
0
13
FINISH (0)
13
0
13
Aggregation with a bar chart
(single resource, earliest start)
activity
1
2
3
4
5
a
1
1
b
4
4
6
7
8
9
10
4
4
4
c
3
3
3
3
3
3
3
3
d
2
2
2
2
2
e
11
12
13
1
1
1
Res. aggr.
5
5
9
9
9
5
5
3
3
3
1
1
1
Cum. res.
5
10
19
28
37
42
47
50
53
56
57
58
59
1
2
3
4
5
6
7
8
9
10
11
12
13
Resource units
11
10
9
8
7
6
5
4
3
2
1
Time
Aggregation with a bar chart
(single resource, latest start)
activity
1
2
a
1
1
3
4
5
b
c
3
3
3
d
6
7
8
9
10
4
4
4
4
4
3
3
3
3
3
2
2
2
2
2
e
11
12
13
1
1
1
Res. aggr.
1
1
3
3
3
9
9
9
9
9
1
1
1
Cum. res.
1
2
5
8
11
20
29
38
47
56
57
58
59
1
2
3
4
5
6
7
8
9
10
11
12
13
Resource units
11
10
9
8
7
6
5
4
3
2
1
Time
The S Curve analysis
• The minimum slope level is the less ‘critical’
from the viewpoint of availability
S Curve of the example
70
60
50
40
ES
LS
30
smoothest
20
10
0
1
2
3
4
5
6
7
8
9
10
11
12
13
Scheduling with constraints
Three approaches:
• Allocation: Activities are scheduled so that an
initially defined limit of resources or time is
not exceeded.
• Levelling: A previously generated schedule
must be given. Then it levels out the peaks
and troughs without changing the TPT.
• Smoothing: A start time, a TPT and resource
priorities.
Other possibilities
• Alternative resources
• Alternative methods
• Alternative sequences
(if there is no technical dependency)
Levelling the load
• We must have a starting allocation of activities over
time and a resource constraint (previous example).
Resource units
11
10
9
8
7
6
5
4
3
2
1
1
2
3
4
5
6
7
8
9
10
11
12
Time
• Trying to keep the original TPT unchanged
means that critical activities should not be
moved. Thus try to move activities with free
float.
13
Solution
• There are only 2 activities with free float: b & d
• Which one to move and to where?
• Moving activity d 3 days in advance is
eliminating the peak.
Resource units
11
10
9
8
7
6
5
4
3
2
1
1
2
3
4
5
6
7
Time
8
9
10
11
12
13
activity
1
2
3
4
5
a
1
1
b
4
4
6
7
8
9
10
4
4
4
c
3
3
3
3
3
3
3
3
d
-
-
-
2
2
2
2
2
e
11
12
13
1
1
1
Res. aggr.
5
5
7
7
7
5
5
5
5
5
1
1
1
Cum. res.
5
10
17
24
31
36
41
46
51
56
57
58
59
S Curve
70
60
50
ES
40
LS
smoothest
30
leveled
20
10
0
1
2
3
4
5
6
7
8
9
10
11
12
13
Effect of levelling
• New „activity”: waiting for the resource
(it is a lag, not a true activity)
0
2
0
0
0
0
0
0
0
0
2
a
(1)
2
2
0
0
0
0
5
b
(4)
5
5
c
(3)
8
10
0
0
0
10
0
5
START (0)
0
2
0
5
0
10
d
(2)
5
10
10
10
0
13
e
(1)
3
13
0
13
0
13
FINISH (0)
13
0
• Changes: new precedence relationship, floats,
late start and finish times
13
Reading
• Lockyer – Gordon (2005): Chapter 17
Thanks for your attention