Basic Networks - Construction Project Scheduling and Control - page 32

Figure 3.8 Redundant versus needed dummy activities
activities are not logically improper; they are simply redundant (see Figure 3.8). ( Note :
Students may lose points on exams for having redundant dummies.)
NODE NETWORKS
Node networks are also called activity on node (AON) networks . In node networks,
we use a different notation for representation: a node represents an activity. Nodes
(activities) are connected with arrows (or lines) that represent logical relationships.
For example, let us redo Examples 3.1 and 3.2 as node diagrams (see Figures 3.9 and
3.10). There is no need in the node diagram for dummy activities. A scheduling novice
can draw a node diagram much easier than an arrow diagram.
For aesthetic reasons only, we like to start any network with one node (whether
this node represents an event or an activity) and end it with one node. Doing so
may require one or two fictitious activities in node diagrams that start or end with
more than one activity. We call these activities PS (project start) and PF (project
finish) , displayed as diamond-shaped nodes. For example, let us redo Examples 3.3
Figure 3.9 Solution for example 3.1 as a node network