1 / 29

PERT / CPM

PERT / CPM. PERT Program Evaluation & Review Technique CPM Critical Path Method. Planning Projects. Tasks: Develop internal and external resource require-ments and time-phase them to the project activities Means of Task Accomplishment:

ivana-hebert
Download Presentation

PERT / CPM

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. PERT / CPM PERT Program Evaluation & Review Technique CPM Critical Path Method

  2. Planning Projects • Tasks: • Develop internal and external resource require-ments and time-phase them to the project activities • Means of Task Accomplishment: • Activity descriptions, milestone charts, cash flow charts, CPM/PERT, engineering designs, time and cost estimates, material delivery plans, and so on. • Timing of Tasks: • Before project is begun and modified as required during project

  3. Scheduling Projects • Tasks: • Develop/revise detailed guides for each resource indicating quantity, quality, and timing • Means of Task Accomplishment: • Milestone charts for departments, subcontractors, and suppliers; cash flow schedule; CPM/PERT: begin-activity and complete-activity dates, and updated activity slack • Timing of Tasks: • Slightly before project is begun and continued throughout project

  4. Controlling Projects • Tasks: • Sense noncompliance of resources with schedules, standards, and budgets; take corrective actions, shift resources, develop alternatives • Means of Task Accomplishment: • Department budget reports, activity cost reports, quality compliance reports, time performance reports • Timing of Tasks: • During project

  5. Critical Path Method (CPM) • Designed to provide intense micro-control • The system is dynamic; it continues to provide periodic reports as the project progresses

  6. Manager’s View of CPM • INPUTS • List of project activities • Precedence relationship among activities • Estimate of each activity’s duration CPM processing procedures • OUTPUTS • Estimated duration of project • Identification of critical activities • Amount of slack for each activity

  7. CPM Terminology • Activity • A task or a certain amount of work required in the project • Requires time to complete • Represented by an arrow • Dummy Activity • Indicates only precedence relationships • Does not require any time of effort

  8. CPM Terminology • Event • Signals the beginning or ending of an activity • Designates a point in time • Represented by a circle (node) • Network • Shows the sequential relationships among activities using nodes and arrows

  9. CPM Terminology • Path • A connected sequence of activities leading from the starting event to the ending event • Critical Path • The longest path (time); determines the project duration • Critical Activities • All of the activities that make up the critical path

  10. CPM Terminology • Earliest Start (ES) • The earliest that an activity can begin; assumes all preceding activities have been completed • Earliest Finish (EF) • ES + activity time • Latest Finish (LF) • The latest that an activity can finish and not change the project completion time • Latest Start (LS) • LF - activity time

  11. IV 1 b d b II a 1 2 V c c a 1 3 III b d a c 1 a c 2 b VI b d 1 CPM Network Conventions a c I a b 1

  12. Steps in CPM Analysis • Draw the CPM network • A graphic view of the relationships among the required activities • Analyze the paths through the network • Determine the length of each path (the time required to complete each path) • Starting at the beginning of the network and working toward the end (from left to right), determine the ES and the EF for each activity • . . . more

  13. Steps in CPM Analysis • Path analysis (continued) • Identify the critical path(s) (the longest path[s] through the network) • The critical path(s) determines how long the project will take • . . . more

  14. Steps in CPM Analysis • Determine the slack for each activity • Working from the end of the project network (from right to left), find the LF and the LS for each activity • Compute the activity’s slack slack = LS - ES = LF - EF • Slack is the maximum amount of time that this activity can be delay in its completion before it becomes a critical activity, i.e., delays completion of the project

  15. A Simple Project

  16. Project Network

  17. ES Earliest Starting (time) EF Earliest Finishing LS Latest Starting LF Latest Finishing Slack Extra Time

  18. Earliest Starting/Finishing Times EF = ES + t

  19. LS = LF - t

  20. What if activity times are variable? a optimistic time m most likely time b pessimistic time t = E(T) expected time = (a + 4m + b)/6 V(T) variance = (b - a)2/36

  21. Activity TimeExpected Value and Variance

  22. Possible Paths and Statistics

  23. What is the probability that the project takes at least 10 days? • What is the probability that the project takes less than 7 days?

More Related