Gantt and PERT charts

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Gantt and PERT charts
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Representing and Scheduling Project Plans

• Gantt Charts
• Useful for depicting simple projects or parts of
  large projects
• Show start and completion dates for individual
  tasks
• PERT Charts
• PERT Program Evaluation Review Technique
• Show order of activities or dependencies between
  activities

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Figure 3-16Graphical diagrams that depict
project plans (a) A Gantt Chart (b) A PERT chart
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Sample PERT Chart
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Comparison of Gantt and PERT Charts

• Gantt
• Visually shows duration of tasks
• Visually shows time overlap between tasks
• Visually shows slack time

• PERT
• Visually shows dependencies between tasks
• Visually shows which tasks can be done in
  parallel
• Shows slack time by data in rectangles

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Critical Path Analysis

• The PERT Algorithm
• By Example

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The Original Graph
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Label all vertices without predecessors. (A B)
Red numbers are the new labels.
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Label all vertices whose predecessors are all
labeled. (C)
Red numbers are the new labels. Blue labels are
from previous steps.
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Label all vertices whose predecessors are all
labeled.(D, E, F)
Red numbers are the new labels. Blue labels are
from previous steps.
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Label all vertices whose predecessors are all
labeled.(G)
17
Red numbers are the new labels. Blue labels are
from previous steps.
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The largest number, 17, is the minimum amount of
time needed to complete the task and ACFG is the
critical path.
D
12
A
3
G
C
E
8
17
10
B
2
F
15
Red arrows represent the critical path.