Project Scheduling EEE455457

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Project SchedulingEEE455/457
Royal Military College of Canada Electrical and
Computer Engineering
LCdr Dean Morrissey Dean.Morrissey_at_rmc.ca 613-541-
6000 ext. 6453 Sawyer S5117
Maj Megan Rakoczy Megan.Rakoczy_at_rmc.ca 613-541-600
0 ext. 6854 Sawyer S4208
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In todays lecture

• Techniques for project planning and control
• Work breakdown structures
• PERT charts
• Gantt charts
• Exercise
• making coffee

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The Work Breakdown Structure

• simply a hierarchy of work elements that
  decomposes a project plan into work elements
• provides a hook for assignment of
  responsibilities
• provides a framework for schedule, budget and
  expenditure
• traditionally structured around modules
• however recently it is felt that a good WBS is
  synchronized with the process not the design
• depicted as a tree
• leaves are generally unit tasks while
  higher-level nodes are composite tasks
• as many layers as necessary typically lt 6

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The Conventional WBS

• structure is based upon the decomposition of the
  product, and is therefore permanently tied to a
  design

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The Evolutionary WBS

• the planning elements are centered on the process
  framework and not the product framework

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Comparison of WBS Types

• Conventional
• tied to a design that may (will) change, may even
  hamper design change
• project specific, and thus cross-project
  comparisons are difficult
• generally either too detailed, too early or
  insufficiently detailed throughout

• Evolutionary
• tied to the process, thus facilitates change
  management
• not project specific, thus facilitates
  cross-project comparisons
• the fidelity of the WBS increases commensurate
  with the project

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WBS and your project

• You choose the type of WBS
• You have elaboration, collaboration, construction
  and management tasks
• You have specific technological work elements
• You must be aware of what must be done to
  mitigate the risk!

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PERT Chart

• Performance
• Evaluation
• Review
• Technique

We are only looking at a portion of PERT
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The PERT Chart

• is an example of an activity-on-node network
• the weight of each node is an activity duration
• an arrow from node A to node B denotes precedence
• A must be complete before B starts
• one start node and one finish node

Create Test Plan (5)
Test UI (3)
Interview User (5)
Win Contract (0)
Design UI (7)
Drink Beer (1)
Code UI (15)
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PERT Chart Information

• Dependencies
• shows clearly how the tasks relate
• Critical Path
• earliest time the project can be finished
• tells you where you need to pay attention
• earliest time a task may start
• same as critical path concept for that task
• latest possible time a task may start
• if a task is off the critical path, it can slip
  without affecting the Critical Path (aka slack)
• crashing
• if we want to finish sooner, which tasks should
  we focus on?

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PERT Example
Earliest Start Finish Times
10 15
22 27
Latest Start Finish Times
Critical Path
27 30
0 5
27 30
0 5
30 31
5 12
5 12
30 31
12 27
12 27
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PERT Chart Pros Cons

• Shows dependencies well
• Critical Path is clear
• Calculating data is labour intensive
• PM software helps
• Not all information is obvious

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The Gantt Chart

• named after its inventor, Henry Gantt
• depicts the time span of each activity against a
  time line
• either elapsed or calendar days
• precedence is depicted by a task having an
  earliest start date defined by all prerequisite
  task completion dates
• depicts any slack time of a task
• permits a start date to occur later than the
  earliest start date
• activities without slack time are on the critical
  path
• zero length events are shown as milestones
• eg delivery of a design document

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PERT to Gantt

• convert the previous PERT chart to a Gantt chart

Days
slack time
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Aside resource allocation
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Gantt Pros Cons

• Shows timeline clearly
• and shows your progress
• Not all dependencies are clearly defined
• Horizontal PERT chart does both
• Again, tools help...

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Tool Support

• many software tools exist to support scheduling,
  most include at least Gantt chart capabilities
• for example see the Excel add-in Projex
• a shareware version can be found at
  http//www.waa-inc.com/projex/index.htm

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Exercise - Making Coffee

• create a PERT chart for this set of tasks
  identify the activities on the critical path
• wait for coffee to brew - 3 minutes
• get cup from office - 1 minutes
• add grounds - 15 seconds
• pour coffee into cup - 10 seconds
• turn on brewer (initiates percolation) - 1 second
• grind beans - 1 minute
• get and add water - 1 minute 30 seconds
• drink coffee - timeless milestone
• insert filter - 15 seconds
• add cream and sugar - 30 seconds

it is a project not an individual task state
all other assumptions
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How does this apply to my project

• You will submit a project schedule in Gantt chart
  format
• You will know your critical path activities
• thus you will know if the project is slipping
• and you will know which tasks are important
• Keep it up to date so you have a good idea as the
  project progresses
• did you estimate task times accurately?
• did you miss some dependencies
• will you finish on time

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Your timeline

• If you estimate a task will take you one day -
  how do you put this in your Gantt chart?
• do you mean one project day (i.e. 4 hours)
• do you mean one full work day/weekend (i.e.
  8hours)
• do you mean homework after reg hours (i.e.
  hours)
• Be wary of double tasking
• Christmas Break
• Reading Break
• Mid-terms
• Ordering/Receiving parts is almost always on the
  critical path

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Supplemental References

• Walker Royce. Software Project Management - A
  Unified Framework, Chapter 10. Addison Wesley,
  1998. ISBN 0-201-30958-0

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