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ELC 347. DAY 8. Agenda. Questions Assignment 3 Corrected 4 A’s , One non-submit Assignment #4 Due Capstone Proposal Due Group Progress report due Exam 2 Slight Change 10 M/C (5 points each) 5 essays (10 points each) 1 hour 15 minutes Open book, Open Notes
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ELC 347 DAY 8
Agenda • Questions • Assignment 3 Corrected • 4 A’s , One non-submit • Assignment #4 Due • Capstone Proposal Due • Group Progress report due • Exam 2 • Slight Change • 10 M/C (5 points each) 5 essays (10 points each) • 1 hour 15 minutes • Open book, Open Notes • Ghattas 4-8, Project 8-10 • Group Project Meeting (30 Min) • Discussion on Network Analysis and Duration Estimating
Network Analysis and Duration Estimating • Laying the Groundwork for Commitment • Setting Duration Estimates • Determining the critical Path • Meeting external deadlines
Groundwork for commitment • Ask the people that actually doing the work • If more than one is capable ask the one with the most experience • Be realistic • Be an advocate for your team
Duration Estimating • Duration – the elapsed time from the start of an activity until it is finished • Effort -- the actual time spent on the project • Example • Tony work on a project task for 20 hours at 4 hours per day starting Monday mourning. The project task was completed Late Friday • Effort – 20 hours • Duration – 5 days
Experience Historical data Research Modeling Experiments Breakdown/roll-up Delphi Method Panel of experts Consultants Three outside Estimates Ranging Other techniques Techniques for Estimating Duration
Special Cases (Out of your hands) • Inspections • Deliveries • Breakdowns and repairs • Approvals
Normalizing Duration • Goal is most “cost-efficient” plan • Determine the most cost-efficient technical approach • Make and estimate of long the most cost efficient method will take to complete • Selectively adjust you estimate for any activity that is subject to common problems.
CPM versus PERT • PERT was developed by US Navy in the 1950s’ • CPM was developed by Remington Rand and DuPont around the same time. • Only difference is in durations estimating • Pert uses 3 cases Most optimistic, most pessimistic and most likely and determines probability for each • DoPo + DpOp +DePe = final duration • CPM use only the most likely duration
Calculating a Project Duration • Determine each activity and its predecessors • Determine an estimated duration for each activity • Find the “Critical Path” • Add up the durations along the critical path
Whats the “Critical Path” • The longest path based on precedence of activities and durations through a PERT/CPM network • It’s critical because • Its combined length determines the length of the project • It has NO slack • Delay of any activities on the critical path delays the entire project
Finding the critical path • Use “forward pass” Calculations • Each activity should have • EPS earliest possible Start time • EPF earliest possible finish time • DUR duration • EPF = EPS + DUR
Special Case • If an activity has more than one processor its EPS is set to the latest EPF of all its processors
Backwards Pass • Use to calculate Slack • LAS -> Latest start time • LAF -> Latest finish time • TS -> total slack
Examine Critical Path for Reality Check • Is the total duration typical? • Are the durations of the CP activities typical? • Reexamine all CP activity durations • Reexamine assumptions
Optimizing the plan • Would bringing more expert talent to bear on the project speed it up? • Are there changes we could make in the resource procurement process to shorten wait times? • Would round the clock scheduling shorten duration? • Would more money motivate the team to work faster? • Would an organizational change speed things up? • Do we think it will take this long just because it always has, or are there other ways to so this, which we haven’t thought of yet, that would shrink the timetable?
3 Lines of defense • Relieve the critical path • Sharpen your pencil • Crash activities
Summary • Construct a CPM • Estimate normal durations • Do a forward pass • Identify Critical Path • Optional • Do a backward pass to identify slack times • Conduct a reality check • Optimize the plan • 1st line of defense - relieve the critical path • 2nd line of defense - sharpen your pencil • 3rd line of defense - crash activities