CPM Practice 2

 

Key Points:

1. Complex Diagram Overview:

   • A more challenging network diagram is introduced, resembling the complexity of diagrams expected on exams.
   • Includes multiple activities (B, C, D, E, F, G, H, and I) with intersections and dependencies.
   • Tasks for learners:
     • Identify the critical path.
     • Perform forward and backward passes.
     • Calculate the float for Activity G.

2. Quick Tips for Handling Complex Diagrams:

   • Forward Pass:
     • For activities with multiple predecessors (e.g., D depends on B and C), choose the largest EF to determine the ES.
   • Backward Pass:
     • For activities with multiple successors (e.g., C depends on D and E), choose the smallest LS to determine the LF.
   • These rules help ensure accurate calculations in convergence and divergence points.

3. Steps to Solve:

   • 1. Identify the Critical Path:
     • Calculate the duration of all paths by summing the durations of activities from start to finish.
     • The path with the longest duration is the critical path.
   • 2. Perform Forward and Backward Pass:
     • Forward Pass:
       • Calculate Early Start (ES) and Early Finish (EF) for all activities.
       • Use the formula: EF = ES + Duration - 1.
     • Backward Pass:
       • Calculate Late Finish (LF) and Late Start (LS) for all activities.
       • Use the formula: LS = LF - Duration + 1.
   • 3. Calculate Float for Activity G:
     • Total Float Formula: TF = LF - EF or TF = LS - ES.

4. Tips for Success:

   • Draw the diagram accurately with clear lines and labels for activities and durations.
   • Follow the principles learned in simpler diagrams:
     • Use the largest EF in the forward pass at convergence points.
     • Use the smallest LS in the backward pass at divergence points.

5. Encouragement:

   • While the diagram may seem intimidating, it adheres to the same principles as simpler ones.
   • With practice, even complex diagrams become manageable.

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Summary:

This video introduces a complex network diagram to practice critical path identification, forward and backward pass calculations, and float determination for a specific activity. Key tips include selecting the largest EF during the forward pass and the smallest LS during the backward pass to manage convergence and divergence points. By applying these principles systematically, learners can confidently tackle complex diagrams and prepare for exam scenarios. The next video will provide answers and further explanations.