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DEVELOPING A PROJECT PLAN
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Developing the Project Plan
A flow chart that graphicallydepicts the sequence,interdependencies, and start andfinish times of the project job planof activities that is the critical path
through the network
TheProject
Network
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Project Network
Provides the basis for scheduling labor and equipment.
Enhances communication among project participants.
Provides an estimate of the projects duration
Provides a basis for budgeting cash flow.
Identifies activities that are critical.
Highlights activities that are critical and can not be delayed.
Help managers get and stay on plan.
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From Work Package to Network
WBS/Work Packages to Network
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From Work Package to Network
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Constructing a Project Network
Activity: an element of theproject that requires time.
Merge activity: an activitythat has two or morepreceding activities onwhich it depends.
Parallel (concurrent)activities: Activities that canoccur independently and, ifdesired, not at the sametime.
Terminology A
C
B D
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Constructing a Project Network
D
C
A B
Path: a sequence ofconnected, dependentactivities.
Critical path: the longest paththrough the activity networkthat allows for the completionof all project-related activities;the shortest expected time inwhich the entire project can
be completed. Delays on thecritical path will delaycompletion of the entireproject.
Terminology
(Assumes that minimum of A + B > minimum of C in length of t imes to complete activities.)
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Constructing a Project Network
B
D
A C
Event: a point in timewhen an activity is
started or completed. Itdoes not consume time.
Burst activity: an activitythat has more than one
activity immediatelyfollowing it (more thanone dependency arrowflowing from it).
Terminology
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Constructing a Project Network
Two Approaches
Uses anode to
depict anactivity
Activity-on-Node
(AON)
Uses anarrow todepict anactivity
Activity-on-Arrow
(AOA)
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Basic Rules to Follow in Developing
Project Networks
Networks typically flow from left to right.
An activity cannot begin until all preceding connected activitiesare complete.
Arrows indicate precedence and flow and can cross over eachother.
Identify each activity with a unique number; this number must begreater than its predecessors.
Looping is not allowed.
Conditional statements are not allowed.
Use common start and stop nodes.
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Comparison of AON and AOA
Methods
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ACTIVITY ON NODE
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Activity-on-Node Fundamentals
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Activity-on-Node Fundamentals
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Network Information
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Koll Business CenterPartial
Network
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Koll Business CenterComplete
Network
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Network Computation Process
Forward PassEarliest Times
How soon can the activity start? (early startES)
How soon can the activity finish? (early finishEF)
How soon can the project finish? (expected timeET)
Backward PassLatest Times
How late can the activity start? (late startLS)
How late can the activity finish? (late finishLF)
Which activities represent the critical path?
How long can it be delayed? (slack or floatSL)
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Network Information
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Activity-on-Node Network
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Activity-on-Node Network
Forward Pass
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Forward Pass Computation
Add activity times along each path in the network(ES + Duration = EF).
Carry the early finish (EF) to the next activity whereit becomes its early start (ES)
The next succeeding activity is a merge activity, inwhich case the largest EF of all preceding activitiesis selected.
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Activity-on-Node Network
Backward Pass
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Backward Pass Computation
Subtract activity times along each path in thenetwork (LF - Duration = LS).
Carry the late start (LS) to the next activity where itbecomes its late finish (LF)
The next succeeding activity is a burst activity, inwhich case the smallest LF of all preceding activitiesis selected.
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Determining Slack (or Float)
Free Slack (or Float)
The amount of time an activity can be delayed without
delaying connected successor activitiesTotal Slack
The amount of time an activity can be delayed withoutdelaying the entire project
The critical path is the network path(s) that has (have) the leastslack in common.
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Sensitivity of a Network
Function of:
The number of critical paths
The amount of slack across near critical
activities
The likelihood the original critical path(s) will changeonce the project is initiated.
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Activity-on-Node Network with
Slack
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Practical Considerations
Network logic errors
Activity numbering
Use of computers to develop networks
Calendar dates
Multiple starts and multiple projects
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Illogical Loop
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Air Control Project
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Air Control Project
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Extended Network Techniques
to Come Close to Reality
Laddering
Activities are broken into segments so the following activity canbegin sooner and not delay the work.
Lags
The minimum amount of time a dependent activity must bedelayed to begin or end
Lengthy activities are broken down to reduce the delay in thestart of successor activities.
Lags can be used to constrain finish-to-start, start-to-start,finish-to-finish, start-to-finish, or combination relationships.
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Example of Laddering Using
Finish-to-Start Relationship
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Use of Lags
Use of Lags to
Reduce Detail
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New ProductDevelopment
Process
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Use of Lags
Finish-to-Finish
Relationship
Start-to-Finish
Relationship
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Network Using Lags
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AOA
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Activity-on-Arrow Network
Building Blocks
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Activity-on-Arrow Network
Fundamentals
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Activity-on-Arrow Network
Fundamentals
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Koll Center Project: Network
Information
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Partial Koll Business Center AOA
Network
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Partial AOA Koll Network
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Partial AOA Koll Network
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Activity-on-Arrow Network
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Activity-on-Arrow Network:
Forward Pass
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Activity-on-Arrow Network:
Backward Pass
Activity-on-Arrow Network
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Activity on Arrow Network
Backward Pass, Forward Pass, and
Slack
l d
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Air Control Inc. Custom Order
ProjectAOA Network Diagram
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END OF CHAPTER