9-7 TaskPredecessorabc Z--7815 YZ131619 XZ141822 WY, X121416 VW1413 TW61014 ST, V111419 1.Sketch the network described in the table. 2.Determine the expected duration and variance of each activity.
9-8 Constructing the Critical Path Forward pass – an additive move through the network from start to finish Backward pass – a subtractive move through the network from finish to start Critical path – the longest path from end to end which determines the shortest project length
9-9 Rules for Forward/Backward Pass Forward Pass Rules (ES & EF) –ES + Duration = EF –EF of predecessor = ES of successor –Largest preceding EF at a merge point becomes EF for successor Backward Pass Rules (LS & LF) –LF – Duration = LS –LS of successor = LF of predecessor –Smallest succeeding LS at a burst point becomes LF for predecessor
9-10 TaskPredecessorTime A--4 BA9 CA11 DB5 EB3 FC7 GD, F3 HE, G2 KH1 1.Sketch the network described in the table. 2.Determine the ES, LS, EF, LF, and slack of each activity
9-11 Laddering Activities Project ABC can be completed more efficiently if subtasks are used A(3)B(6)C(9) ABC=18 days Laddered ABC=12 days A 1 (1)A 2 (1)A 3 (1) B 1 (2)B 2 (2)B 3 (2) C 1 (3)C 2 (3)C 3 (3)
9-12 Hammock Activities Used as summaries for subsets of activities 0 A5 0 55 5 B15 5 1015 15 C18 15 318 0 Hammock18 01818 Useful with a complex project or one that has a shared budget
9-13 Reducing the Critical Path Eliminate tasks on the CP Convert serial paths to parallel when possible Overlap sequential tasks Shorten the duration on critical path tasks Shorten –early tasks –longest tasks –easiest tasks –tasks that cost the least to speed up