1. Drawing the AON network
Project Management
(lecture)

2. Elements of an AoN diagram
Activity (node)
Work element or task
Name or identification of the tasks must be added
No need for dummy (unreal) activities
Dependency or sequence arrow
Shows the interrelationship between activities

3. Conventions Time flows from left to right
Arrows’ direction
Labels’ increase
Head nodes always have a greater/higher label (letter) that of the tail node.
A complete network has only one starting and only one ending event.

4. Examples of activity combinations

5. Graphical representation
Representation of dependency time: lags
Activity duration times & finish to start dependency
Representation of milestones/deadlines (external constraints): Identified by an inverted triangle over the activity node (occasionally with an imposed time for the event)

6. Overlapping activities
If the activities are not fully discrete
The second activity can start before the first is completed but not before it is at least partly completed.
Breaking activities into components

7. Interfacing
When an activity is common to two or more subnetworks it is said to be an ‘interface’ activity between those subnetworks and is represented by a pair of concentric circles or rectangles.

8. Two errors in logic Looping: underlying logic must be at fault
Dangling: an activity is undertaken with no result

9. Hammock activities
Artificial activities created for the representation of the overhead cost with the aim of cost control.
Embrace activities belong to the same cost centre
Zero duration time (not taking part in the time analysis)
Overhead cost rate is assumed to be constant over the life of the hammock.

10. Multiple starts and finishes
Only used in computer programs
All starting activities can occur at the start and all finish activities will occur at the end of the project.

11. CPA, CPM and PERT
Critical Path Analysis (CPA), Critical Path Method (CPM)
deterministic with only one estimation
Program Evaluation and Review Technique (PERT)
probabilistic with three estimated durations

12. Readings
Lockyer – Gordon (2005) Chapter 12

13. Thanks for the attention!