Reid & Sanders, Operations Management © Wiley 2002 Project Management 17 C H A P T E R.
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Transcript of Reid & Sanders, Operations Management © Wiley 2002 Project Management 17 C H A P T E R.
Reid & Sanders, Operations Management© Wiley 2002
Project Management 17C H A P T E R
Page 2Reid & Sanders, Operations Management© Wiley 2002
Learning Objectives
• Describe the project life cycle• Describe the critical path method (CPM)• Describe the program evaluation & review technique
(PERT)• Distinguish Activity-on-Arrow (AOA) & Activity-on-
Node Diagrams• Estimate the completion time of a project• Identify critical activities that cannot be delayed
without delaying the project• Calculate the amount of available slack for non-
critical activities
Page 3Reid & Sanders, Operations Management© Wiley 2002
Definitions
• Project:– An endeavor with specific objectives & multiple
activities with defined precedence relationships, to be completed within a limited duration
• Activities:– Specific tasks that must be completed & require
resources
• Precedence relationships:– A natural order between activities, where some
tasks must be complete before others can begin
Page 4Reid & Sanders, Operations Management© Wiley 2002
Project Life Cycle
• Conception
• Feasibility analysis or study
• Planning
• Execution
• Termination
Page 5Reid & Sanders, Operations Management© Wiley 2002
Network Planning Techniques
• Critical Path Method (CPM):– Developed to coordinate maintenance projects in
the chemical industry– A complex undertaking, but individual tasks are
routine (tasks’ duration = deterministic)
• Program Evaluation & Review Technique (PERT):– Developed to manage the Polaris missile project– Many tasks pushed the boundaries of science &
engineering (tasks’ duration = probabilistic)
Page 6Reid & Sanders, Operations Management© Wiley 2002
Both CPM & PERT
• Graphically display the precedence relationships & sequence of activities
• Estimate the project’s duration
• Identify critical activities that cannot be delayed without delaying the project
• Estimate the amount of slack associated with non-critical activities
Page 7Reid & Sanders, Operations Management© Wiley 2002
Notation
• Activity-on-Arrow (AOA):– Each arrow represents an activity & its
precedence relationship(s)– May require the use of “dummy” arrows if the
activity has more than one successor task– Nodes used only as end-points for arrows
• Activity-on-Node (AON):– Uses nodes to represent the activity– Uses arrows to represent precedence
relationships
Page 8Reid & Sanders, Operations Management© Wiley 2002
AOA & AON Comparison
Page 9Reid & Sanders, Operations Management© Wiley 2002
Example
Activity DescriptionImmediate
PredecessorDuration (weeks)
A Develop product specifications None 4B Design manufacturing process A 6C Source & purchase materials A 3D Source & purchase tooling & equipment B 6E Receive & install tooling & equipment D 14F Receive materials C 5G Pilot production run E & F 2H Evaluate product design G 2I Evaluate process performance G 3J Write documentation report H & I 4K Transition to manufacturing J 2
Page 10Reid & Sanders, Operations Management© Wiley 2002
AOA Diagram
Page 11Reid & Sanders, Operations Management© Wiley 2002
AON Diagram
Page 12Reid & Sanders, Operations Management© Wiley 2002
Add Activity Durations
Page 13Reid & Sanders, Operations Management© Wiley 2002
Identify Unique Paths
Page 14Reid & Sanders, Operations Management© Wiley 2002
Calculate Path Durations
• The longest path (ABDEGIJK) limits the project’s duration (project cannot finish in less time than its longest path)
• ABDEGIJK is the project’s critical path
Paths Path durationABDEGHJK 40ABDEGIJK 41ACFGHJK 22ACFGIJK 23
Page 15Reid & Sanders, Operations Management© Wiley 2002
Calculating the Slack of Non-Critical Activities
• All activities on the critical path have zero slack
• Slack defines how long non-critical activities can be delayed without delaying the project
• Slack = the activity’s late finish minus its early finish (or its late start minus its early start)
Page 16Reid & Sanders, Operations Management© Wiley 2002
Calculate Activities’Early Starts & Finishes
Page 17Reid & Sanders, Operations Management© Wiley 2002
Calculate the Activities’Late Starts & Finishes
Page 18Reid & Sanders, Operations Management© Wiley 2002
Calculate Slack
ActivityLate
FinishEarly Finish
Slack (weeks)
A 4 4 0B 10 10 0C 25 7 18D 16 16 0E 30 30 0F 30 12 18G 32 32 0H 35 34 1I 35 35 0J 39 39 0K 41 41 0
Page 19Reid & Sanders, Operations Management© Wiley 2002
Revisit Example UsingProbabilistic Time Estimates
Activity DescriptionOptimistic
timeMost likely
timePessimistic
timeA Develop product specifications 2 4 6B Design manufacturing process 3 7 10C Source & purchase materials 2 3 5D Source & purchase tooling & equipment 4 7 9E Receive & install tooling & equipment 12 16 20F Receive materials 2 5 8G Pilot production run 2 2 2H Evaluate product design 2 3 4I Evaluate process performance 2 3 5J Write documentation report 2 4 6K Transition to manufacturing 2 2 2
Page 20Reid & Sanders, Operations Management© Wiley 2002
Use Beta Distribution to Estimate Expected Task Durations
6
cpessimistilikelymost 4optimistic timeExpected
Page 21Reid & Sanders, Operations Management© Wiley 2002
Expected Task Durations
ActivityOptimistic
timeMost likely
timePessimistic
timeExpected
timeA 2 4 6 4B 3 7 10 6.83C 2 3 5 3.17D 4 7 9 6.83E 12 16 20 16F 2 5 8 5G 2 2 2 2H 2 3 4 3I 2 3 5 3.17J 2 4 6 4K 2 2 2 2
6
cpessimistilikelymost 4optimistic timeExpected
Page 22Reid & Sanders, Operations Management© Wiley 2002
Build AOA Network& Identify Paths
Page 23Reid & Sanders, Operations Management© Wiley 2002
Estimate Path Durations
• ABDEGIJK is the expected critical path & the project has an expected duration of 44.83 weeks
Activities on paths Expected durationABDEGHJK 44.66ABDEGIJK 44.83ACFGHJK 23.17ACFGIJK 23.34
Page 24Reid & Sanders, Operations Management© Wiley 2002
The End
• Copyright © 2002 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in Section 117 of the 1976 United State Copyright Act without the express written permission of the copyright owner is unlawful. Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The purchaser may make back-up copies fo