PERT AND CPM PROJECT MANAGEMENT
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Project management techniques like PERT and CPM are used to plan, schedule, and control projects. PERT was developed for the Polaris missile program to minimize time, while CPM was developed by DuPont to optimize cost and time tradeoffs. Both methods use network diagrams to visually display tasks and their relationships. They are used to estimate duration, identify critical paths, and determine slack. PERT additionally accounts for uncertainty in durations using three time estimates.
PERT AND CPM PROJECT MANAGEMENT
- 1. PERT AND CPM PROJECT MANAGEMENT ARCHITECTURE SITI YAUMILIA SALSA
- 2. Project Combination of interrelated activities Executed in logical sequence Accomplishment of a desired objective
- 3. Project Management • Management is generally perceived as concerned with planning, organizing, and control of an ongoing process or activity. • Project Management is concerned with control of an activity for a relatively short period of time after which management effort ends. • Primary elements of Project Management to be discussed: Project Team Project Planning Project Control
- 4. Network analysis is the general name given to certain specific techniques which can be used for the planning, management and control of projects. Methods used for network planning are: CPM PERT Managing a project with network planning methods involves four steps: 1. Describing the Project. 2. Diagramming the Network. 3. Estimating time of completion. 4. Monitoring Project Progress. Network Planning
- 5. HISTORY OF PERT/CPM Developed by the US Navy for the planning and control of the Polaris missile program The emphasis was on completing the program in the shortest possible time. PERT Developed by Du Pont to solve project scheduling problems The emphasis was on the trade-off between the cost of the project and its overall completion time CPM
- 6. CPM - Critical Path Method Drafting the design of Programme or Project Evaluation of drafted Programme or Project Review of evaluated Programme or Project
- 7. PERT - Project Evaluation & Review Techniques To analyze and represent the tasks involved in completing a given project Accommodates the variation in event completion time Event-oriented technique rather than start- and completion-oriented Commonly used in conjunction with the critical path method
- 8. Basic Terms In Network Analysis Activity Event Constraints Network Diagram Critical Path
- 9. Steps in PERT/CPM 4. CONTROLLING 3. ALLOCATION OF RESOURCES 2. SCHEDULING 1. PLANNING
- 10. PERT/CPM Project managers reply on PERT/CPM to help them answer questions such as: • What is the total time to complete the project? • What are the scheduled start and finish dates for each specific activity? • Which activities are critical and must be completed exactly as scheduled to keep the project on schedule? • How long can noncritical activities be delayed before they cause an increase in the project completion time?
- 11. Both PERT and CPM • Graphically display the precedence relationships & sequence of activities • Estimate the project’s duration • Identify critical activities that cannot be delayed without delaying the project • Estimate the amount of slack associated with non-critical activities
- 12. Framework for PERT and CPM • Define the Project. The Project should have only a single start activity and a single finish activity. • Develop the relationships among the activities. • Draw the "Network" connecting all the activities. • Assign time and/or cost estimates to each activity • Compute the critical path. • Use the Network to help plan, schedule, monitor and control the project.
- 13. PERT Diagrams • Activity-on-node diagrams: • Maybe more than one single start and end node • Nodes represent activities • Arrows indicate precedence • Activity-on-arrow diagrams: • One single start and one single end node • An arrow represents a task, while a node is the completion of a task • Arrows represent activities • Nodes indicate beginning/end of activities 13
- 14. Dummy Activities • Sometimes it is necessary to insert dummy activities (duration zero) in order to maintain the clarity of the diagram and the precedence relationships between activities. • In activity-on-arrow PERT diagrams, each activity must be uniquely identifiable by its start and end nodes. • However, sometimes multiple tasks have the same predecessors and successors. 14
- 15. DUMMY ACTIVITY Dummy Activity is used in two situations: 1) When two or more activities start and end at the same nodes 1 3 2 2) When two or more activities share the same precedence activity but not all the precedence are shared. 1 53 6 7 2 4
- 16. Determining the Critical Path • Step 1: Make a forward pass through the network as follows: For each activity i beginning at the Start node, compute: • Earliest Start Time (ES) = the maximum of the earliest finish times of all activities immediately preceding activity i. (This is 0 for an activity with no predecessors.). This is the earliest time an activity can begin without violation of immediate predecessor requirements. • Earliest Finish Time (EF) = (Earliest Start Time) + (Time to complete activity i. This represent the earliest time at which an activity can end. The project completion time is the maximum of the Earliest Finish Times at the Finish node.
- 17. Determining the Critical Path • Step 2: Make a backwards pass through the network as follows: Move sequentially backwards from the Finish node to the Start node. At a given node, j, consider all activities ending at node j. For each of these activities, (i,j), compute: • Latest Finish Time (LF) = the minimum of the latest start times beginning at node j. (For node N, this is the project completion time.). This is the latest time an activity can end without delaying the entire project. • Latest Start Time (LS) = (Latest Finish Time) - (Time to complete activity (i,j)). This is the latest time an activity can begin without delaying the entire project.
- 18. Determining the Critical Path • Step 3: Calculate the slack time for each activity by: Slack = (Latest Start) - (Earliest Start), or = (Latest Finish) - (Earliest Finish). A critical path is a path of activities, from the Start node to the Finish node, with 0 slack times.
- 19. A Simple Project Activity Immediate Predecessor Expected Time A - 5 B - 6 C A 4 D A, B 2
- 21. ES Earliest Starting (time) EF Earliest Finishing LS Latest Starting LF Latest Finishing Slack Difference Time
- 23. • Activity time estimates usually can not be made with certainty. • PERT used for probabilistic activity times. • In PERT, three time estimates are used: most likely time (m), the optimistic time (a) , and the pessimistic time (b). • These provide an estimate of the mean and variance of a beta distribution: • mean (expected time): • variance: 6 b4mat 2 6 a-b v Probabilistic Activity Times
- 25. Difference Between PERT & CPM Probabilistic Model Non-repetitive Jobs like planning & scheduling of programmes Results calculated on basis of Events Related with activities of uncertain time Deterministic Model Repetitive Jobs like residential construction Results calculated on basis of activities Related with activities of Well Known time PERT CPM
- 26. Advantages of PERT/CPM Reduction in cost • Elimination of Risk in Complex activity Flexibility • Optimisation of Resources Reduction of Uncertainties
- 27. Disadvantages of PERT/CPM Network charts tend to be large Lack of a timeframe on most PERT/CPM charts makes it harder to show status When PERT/CPM charts become unwieldy, they are no longer used to manage the project Planning & Implementation required skillful personnel
- 28. PERT TABLE NO. ACTIVITY KOEFISIEN Days Labors Toptimis (a) Tmostlikely (m) Tpesimis (b) Texpected (Te) Variance (v) A PREPARATION, MINING AND LAND 32 6,10,16 8,5/6,4 6 10 16 10,33333333 2,777777778 B FOUNDATION AND CONCRETE CONSTRUCTION 240 40,60,80 8,6,4 40 60 80 60 44,44444444 C COUPLE AND PLASTERING CONSTRUCTION 12 2,4,6 6,4,3 2 4 6 4 0,444444444 D FLOOR AND WALL INSTALLATION 12 1,1,4 4,4,1 4 10 12 9,333333333 1,777777778 E ROOF CONSTRUCTION 42 6,7,11 7,6,4 11 14 21 14,66666667 2,777777778 F CEILING INSTALLATION 4 1,1,4 4,4,1 1 1 4 1,5 0,25 G INSTALLATION KUSEN, DOOR AND WINDOW 15 2,3,5 8,5,3 2 3 5 3,166666667 0,25 H EQUIPMENT INSTALLATION DOOR AND WINDOW 6 1,2,3 6,3,2 1 2 3 2 0,111111111 I INSTALLATION OF SANITARY 24 3,4,6 8,6,4 3 4 6 4,166666667 0,25 J1 SEPTIC TANK 10 4,5,10 3,2,1 4 5 10 5,666666667 1 J2 PLUMBING 7 3,4,7 3,2,1 3 4 7 4,333333333 0,444444444 K1 PLN INSTALLATION 1 1,1,2 2,1,1 1 1 2 1,166666667 0,027777778 K2 CABLE 3 1,2,3 3,2,1 1 2 3 2 0,111111111 K3 FINISHING 1 1.2.3 2,1,1 1 1 2 1,166666667 0,027777778 L PAINTING 7 1,1,3 1,1,3 3 4 7 4,333333333 0,444444444 M FINISHING 8 3,4,8 3,2,1 3 4 8 4,5 0,694444444
- 29. PERT DIAGRAM A B C K1 E F J2J1 G I D L H K2 I K3 M NO. ACTIVITY Texpected (Te) A PREPARATION, MINING AND LAND 10,33 B FOUNDATION AND CONCRETE CONSTRUCTION 60 C COUPLE AND PLASTERING CONSTRUCTION 4 D FLOOR AND WALL INSTALLATION 9,33 E ROOF CONSTRUCTION 14,67 F CEILING INSTALLATION 1,5 G INSTALLATION KUSEN, DOOR AND WINDOW 3,17 H EQUIPMENT INSTALLATION DOOR AND WINDOW 2 I INSTALLATION OF SANITARY 4,17 J1 SEPTIC TANK 5,67 J2 PLUMBING 4,34 K1 PLN INSTALLATION 1,17 K2 CABLE 2 K3 FINISHING 1,17 L PAINTING 4,34 M FINISHING 4,5
- 31. S ^ = 54,25 S=7,365459931328117 Z=(120-115,5)/ 7,365 Z= 0,61 Z= 74,8 % NO. ACTIVITY Variance (v) CRITICAL PATH A PREPARATION, MINING AND LAND 2,777777778 YA B FOUNDATION AND CONCRETE CONSTRUCTION 44,44444444 YA C COUPLE AND PLASTERING CONSTRUCTION 0,444444444 YA D FLOOR AND WALL INSTALLATION 1,777777778 YA E ROOF CONSTRUCTION 2,777777778 YA F CEILING INSTALLATION 0,25 YA G INSTALLATION KUSEN, DOOR AND WINDOW 0,25 YA H EQUIPMENT INSTALLATION DOOR AND WINDOW 0,111111111 YA I INSTALLATION OF SANITARY 0,25 YA J1 SEPTIC TANK NO J2 PLUMBING NO K1 PLN INSTALLATION NO K2 CABLE NO K3 FINISHING 0,027777778 YA L PAINTING 0,444444444 YA M FINISHING 0,694444444 YA S^2 54,25
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