The document discusses project network development and analysis. It defines a project network as a diagram that depicts the sequence, dependencies, and timing of project activities. It then:
1. Explains how networks are developed from work breakdown structures and used for scheduling, budgeting, and identifying critical paths.
2. Describes the activity-on-node approach and basic network terminology like activities, paths, and critical path.
3. Provides examples of network development, computation of early and late start/finish times using forward and backward passes, and determining slack.
3. Project Network
–A diagram that graphically depicts the
sequence, interdependencies, and start and
finish times of the project activities
The network is developed from the information
collected in the work breakdown structure
Provides the basis for scheduling labor and equipment.
Provides an estimate of the project’s duration
Provides a basis for budgeting cash flow
Tool that highlights activities that are “critical” and
should not be delayed
Help managers get and stay on plan
6. Terminology
Activity: an element of the
project that requires time. It
represented as a “node” (box)
Merge activity: This is an
activity that has more than
one activity immediately
preceding it.
Burst Activity- This
activity has more than one
activity immediately
following it.
McGraw-Hill/Irwin 6–6
7. McGraw-Hill/Irwin 6–6
Terminology
Path: a sequence of connected, dependent activities.
Critical path: is the longest path through the activity
network from the beginning to the end that allows for the
completion of all project-related activities.
8. BASIC GUIDELINES TO FOLLOW IN DEVELOPING
PROJECT NETWORKS
McGraw-Hill/Irwin 6–8
1. Networks typically flow from left to
right.
2. An activity will be performed in
sequence.
3. Unique, sequential ID.
4. Arrows can cross over .
5. No Conditional statements.
6. Looping is not allowed.
7. With multiple starts, use a common
start node and similarly, use a
common end node.
22. Extended Network Techniques
to Come Close to Reality
• Laddering
-under the standard finish-to-start relationship, the activity must be
100% completed before advancing to the next activity. If that activity
has a long duration and if that activity has a delay, that activity can be
broken down into segments using laddering so that the following
activity can begin sooner without delaying work.
23. Extended Network Techniques to Come
Close to Reality
• Lags
• The minimum amount of time a dependent activity must be
delayed to begin or end
• Lengthy activities are broken down to reduce the delay in the
start of successor activities.
• Lags can be used to constrain finish-to-start, start-to-start,
finish-to-finish, start-to-finish, or combination relationships.
Use of Lags:
1. Finish-to-Start Relationship
-The finish-to-start relationship
represents the typical, generic network
style used in the early part of the
chapter.
2. Start-to-Start Relationship
-An alternative to segmenting the
activities as we did earlier is to use a
start-to-start relationship.
26. Hammock Activities
• Another of the extended techniques uses a hammock
activity.
• This type of activity derives its name because it spans over a
segment of a project.
• The hammock activity duration is determined after the
network plan is drawn.
• Are frequently used to identify the use of fixed resources or
costs over a segment of the project.
• Typical examples of hammock activities are inspection
services, consultants, or construction management services.
• Derives its duration from the time span between other
activities.
Chapter 5 estimating project time and cost
Assumption
Types of estimates
Topdown (macro)
Bottom Up ( micro)
Factors na nakakaimplunce sa quality ng estimates
Planing horizon
Project complexity
People
Project structure and organization
Padding estimates
Organization culture
Other non project factors
Type of cost
Direct cost- labor, materials
Direct project overhead cost- salary rents supplies
General and administrative overhead cost – cost na di connected sa specific project
It can be used to enhance communication among project participants
Activity- an element of the project that requires time either work or wait. Or may not require resources.
Activity that consume resources are easy to understand.
The diagram is a part of a project network
It has four activities a,b, c,d
There are three basic relationship among activities:
Predecessor- (sumusunod )A is C predecessor B is also C predecessor
Successors- (sinusundan) C is A and B sucessor
Concurrent - A and B are Concurrent or parallel activities
C and D are also concurrent activities
Merge – that means more than one dependency arrow flowing into it
In this example C is a merge activity
This activity has more than one imidiate succesors
That means more than one dependency arrow flowing from it.
B is a burst activity
A-B-C is a Path
B-C-E
A-D-E
Critical path marks the shortest expected time in which the entire project can be completed.
Delays on non- critical path may not delay the entire project but delays on the critical
But When an activity on the critical path is delayed, completion of the entire project will definitely delay.
In this diagram the number above or below the activities are their DURATIONS
Activity A takes 2 days to complete
We have 2 paths from the beginning node A to the end node E.
A-B-C-E and A-D-E
10 days and 11 days
Therefore the critical path is A-D-E because its longer
2. An activity cannot begin until all preceding connected activities have been completed
3. Each activity should have a unique identification code. it could be a letter or number. An activity identification number must be larger than that of any activities that precede it.
4. Arrows on networks indicate precedence and flow. Arrows can cross over each other.
5. Fith rule is that conditional statements are not permitted in a project network.
(that is, this type of statement should not appear: If successful, do something; if not, do nothing
Example if test is successful then build the prototype otherwise redesign
6. Also looping is not allowed in the project network
Diagram is the example of looping
It attempts to return to an earlier activity from Zto X
If this loop were allowed this path would perpetually repeat itself and the project and the project will never end.
Experience suggests that when there are multiple starts, a common start node can be used to indicate a clear project beginning on the network. Similarly, a single project end node can be used to indicate a clear ending
The activity on AON method has come t dominate most projects, and we will only introduce this method.
Activity can include one or more work packages
Mas maganda na parehong tao and mag developed the wbs at project network to guarantee the consistency and continuity.
A is the starting node of the project network.
A is the predecessor of B and C