Friday, 14 February 2020

Network Planning Model

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Network Planning Model


? A Network Planning Model is a pictorial representation of the sequence in which the
project work can be done. There are two ways to build a project schedule: (a) Gantt chart
and (b) Network diagram.
? The Gantt chart is the older of the two and is used effectively in simple, short-duration
types of projects. The network diagram provides a visual layout of the sequence in which
project work flows.
? It includes detailed information and serves as an analytical tool for project scheduling and
resource management problems as they arise during the life of the project.
? Network diagrams can be used for detailed project planning, during implementation as a
tool for analyzing scheduling alternatives, and as a control tool.
? You can build the Network Diagram using the Precedence Diagramming Method which is
also known as the activity-on-the-arrow (AOA) method. Each activity in the network
diagram is represented by a rectangle that is called an activity node.
? The entries in the activity node describe the time-related properties of the activity. Some
of the entries describe characteristics of the activity, such as its expected duration (E),
while others describe calculated values (ES, EF, LS, LF) associated with that activity.
? The network diagram is logically sequenced. It is read from left to right. Every activity in
the network, except the ‘start’ must have at least one activity that comes before it (its
immediate predecessor). Similarly, every activity in the network, except the ‘end’ must
have at least one activity that comes after it (its immediate successor).
? There are four types of constraints:
? Technical constraints
? Management constraints
? Interproject constraints and
? Date constraints.
? Pauses or delays between activities are indicated in the network diagram through the use
of lag variables. In situation where, the initial project completion date is later than the
requested completion date, you must find ways to reduce the total duration of the project
to meet the required date.

 ? What you will now have to do is adjust and readjust the critical path.
? This is known as schedule compression. Management reserve allows a project manager to
use percentages to see how the overall project is coming along.


A Project Network Diagram: A Network Planning Model is a pictorial representation of the
sequence in which the project work can be done. The whole idea here is look at your work
visually and think about in what order (sequence) the work needs to occur.
Gantt Chart: The Gantt chart is the older of the two and is used effectively in simple, shortduration
types of projects.
Network Diagram: The network diagram provides a visual layout of the sequence in which
project work flows.
Dependency: A dependency is simply a relationship that exists between pairs of activities. To say
that activity B depends on activity A means that activity A produces a deliverable that is needed
in order to do the work associated with activity B.
Critical Path: The sequence of activities that determine the project completion date is called the
critical path.
Fast tracking: This method allows activities to be done in parallel that would normally be done
in sequence.
Crashing: Crashing allow the project manager to add more resources to effort-driven activities
in an attempt to shorten their duration.
Lead time: Lead time is negative time. It brings activities closer together—even allowing them
to overlap.
Lag time: Lag time is waiting time.
Management Reserve: Management reserve allows a project manager to use percentages to see
how the overall project is coming along. For example, if the project is only 40 per cent complete
but the management reserve is 65 per cent used, then the project is in trouble if the remaining
tasks follow the trend of the project thus far.

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