Project Planning and Scheduling

Transcription

1 Chapter 6, Section Project Planning and Scheduling 1 Learning Outcome Apply engineering management principles and tools (e.g., Gantt charts, CPM) to the planning and management of work systems engineering projects. Project Management Plan the work List project tasks List precedence requirements Allocate resources to determine time Work the plan Execute Continually revise and update plan

2 Gantt Charts: Cesarean Section Facilitator Project List of tasks on Y axis, time on X axis Bars show planned start and finish times and actual progress. Advantages: Shows situation at a glance Is easy to modify (without computers or math)

3 Critical Path Method (CPM) Define Activities/Tasks Activity precedence relationships Activity times Construct network (graph) Node = beginning of activity Arc (line) = activity Number on arc = duration of activity Make forward pass Find earliest possible start times Maximum of incoming paths Make backward pass Find latest necessary start times to finish on schedule Minimum of outgoing paths Calculate slack times Latest earliest Critical path is path with zero slack ( Simplified PERT ) Graphically shows sequence and precedence of tasks Numbers show forward pass and backward pass times. Advantages: Shows potential problems Shows which tasks should be expedited (critical path) Sets up progress checkpoints Tends to be self-fulfilling

4 CPM Steps Define Activities/Tasks Activity precedence relationships Activity times Construct network (graph) Node = beginning of activity Arc (line) = activity Number on arc = duration of activity Make forward pass Find earliest possible start times Maximum of incoming paths Make backward pass Find latest necessary start times to finish on schedule Minimum of outgoing paths Calculate slack times Latest earliest Critical path is path with zero slack

5 Preparing a Meal Number Activity Follows Precedes Minutes 1 Set up kitchen 1 Instruct helper on salad preparation 1, Prepare salad ingredients Assemble salad 7 Prepare spaghetti ingredients 6 6 Assemble spaghetti 7 7 Serve meal,6 8 8 Begin meal 7

6 CPM Steps Define Activities/Tasks Activity precedence relationships Activity times Construct network (graph) Node = beginning of activity Arc (line) = activity Number on arc = duration of activity Make forward pass Find earliest possible start times Maximum of incoming paths Make backward pass Find latest necessary start times to finish on schedule Minimum of outgoing paths Calculate slack times Latest earliest Critical path is path with zero slack 6

7 Construct Network 1 7

8 Construct Network 1 8

9 Construct Network 1 9

10 Construct Network 1

11 Construct Network 1 11

12 Construct Network 1 6 1

13 Construct Network

14 Construct Network

15 Construct Network (neatly)

16 Construct Network

17 CPM Steps Define Activities/Tasks Activity precedence relationships Activity times Construct network (graph) Node = beginning of activity Arc (line) = activity Number on arc = duration of activity Make forward pass Find earliest possible start times Maximum of incoming paths Make backward pass Find latest necessary start times to finish on schedule Minimum of outgoing paths Calculate slack times Latest earliest Critical path is path with zero slack 17

18 Forward Pass

19 Forward Pass

20 Forward Pass

21 Forward Pass /

22 Forward Pass /

23 CPM Steps Define Activities/Tasks Activity precedence relationships Activity times Construct network (graph) Node = beginning of activity Arc (line) = activity Number on arc = duration of activity Make forward pass Find earliest possible start times Maximum of incoming paths Make backward pass Find latest necessary start times to finish on schedule Minimum of outgoing paths Calculate slack times Latest earliest Critical path is path with zero slack

24 Backward Pass /

25 Backward Pass /

26 Backward Pass /

27 Backward Pass / /

28 Backward Pass / /

29 CPM Steps Define Activities/Tasks Activity precedence relationships Activity times Construct network (graph) Node = beginning of activity Arc (line) = activity Number on arc = duration of activity Make forward pass Find earliest possible start times Maximum of incoming paths Make backward pass Find latest necessary start times to finish on schedule Minimum of outgoing paths Calculate slack times Latest earliest Critical path is path with zero slack 9

30 Critical Path / /

31 Project Evaluation and Review Technique ( Enhanced PERT ) 1 Uses three time estimates (optimistic, most likely, pessimistic) Requires estimate of task costs for normal and crash time Advantages: Permits estimate of time variability Permits tradeoff of task times against cost