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Bpp 3213 lecture 2


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Bpp 3213 lecture 2

  1. 1. BPP 3213 PROJECT ESTIMATION AND SCHEDULINGLecture 2 Network Scheduling and Precedence Diagram Method (PDM) Oct, 2012 Faculty of Technology Universiti Malaysia Pahang Jane Doe & Jane Doe
  2. 2. RECAPOrganization Structure Challenges Project life cycle
  3. 3. Purpose of this lectureTo better understand:• brief history of scheduling techniques• network scheduling and logic diagrams• the importance of Critical Path Method (CPM)• the fundamental elements of precedence diagrammethod (PDM)
  4. 4. Scheduling is for everyone it is a discipline that isperformed by every person,every day. Scheduling is an application of special knowledge or judgment of the mathematical , physical, or engineering sciences to the conception or implementation of creative work.
  5. 5. The History
  6. 6. Brief History Gantt Charts / Bar ChartsHistory Advantage DrawbackUntil 1958, the only tool Simple to construct and difficult to determine thefor project scheduling read impact of slip on one taskwas a bar chart on the rest of the projectHenry Gantt haddeveloped a completenotational systemshowing progress withbar chart, thus theycalled Gantt charts
  7. 7. Brief History (cont’d)Arrow DiagramsHistory Advantage DrawbackLate 1950s and early An arrow diagram Tend to be too1960s, two methods help the team complicated forof scheduling were understand the some teamsdeveloped to interdependencies ofcapture the the taskssequential andparallel relationshipsamong projectactivities
  8. 8. Brief History (cont’d) Critical Path Method (CPM)History Advantages DrawbacksDeveloped by Du Pont in Graphical view of the CPM can be complicated,1957 project and complexity increases for larger projects Initially to address the Predicts the time requiredchallenge of shutting down for the project Does not handling thechemical plants for scheduling of personnel andmaintenance and restarting Shows which activities are resource allocationit again once maintenance critical to maintain thecompleted schedule and which are not Not always clear and need to be calculated carefullyUtilizes the planner’sknowledge, experience, and Estimating activityinstincts in a logical way completion times can be difficult
  9. 9. Brief History (cont’d) Program Evaluation and Review Technique (PERT)History Advantages DrawbacksDeveloped by US Navy It allows for Complicated chartand Booze, Allen and randomness in activityHamilton at late 1950’s completion times Prediction inaccuracies Has potential of reducing both time and cost required to complete the project
  10. 10. Brief History (cont’d)
  11. 11. Purpose of aSchedule
  12. 12. Purpose of Schedule • Schedules are tool to :Communicate time Assess time plan plan
  13. 13. Purpose of Schedule (cont’d) Benefits:- Identify the timeframe- Identify the resource requirement- identify the key milestones- Identify the key stakeholder engagementpoints- Assess impact of resource constraints- Determine your commitment and obstacles
  14. 14. Schedule Development ProcessNetwork-logicEstimates - times Project Scheduling ScheduleResource capabilityResource capacity
  15. 15. Example Gantt Chart
  16. 16. Logic Diagram &Networks
  17. 17. Your New Tool•Defacto standard for scheduling software inconstruction industry has been Primavera ProjectPlanner aka P3•In 2000, P3 has improved for the use bymanufacturing and IT industries
  18. 18. Your New Tool (cont’d)•Major differences that distinguish one softwaresystem from another are •Ease of input •Ease and variety of means of reporting output •Features that permit the user to get around some of the limitation of the math upon which CPM is founded to more perfectly model the real world
  19. 19. Logic Diagrams and Networks• Effective project plan – address equally theparameters and activity logic• Illustrate the inductive and deductive reasoning toachieve objectives within time given• Constructed similarly to bar charts – supposingnothing will go wrong• Normally accompanied by detailedquestions/checklist
  20. 20. The Logic of the Logic Diagrams• backbone of traditional implementation of CPM isgraphical model of a project•Basic component is the arrow•Each arrow represents one activity in a project activity start finish
  21. 21. The Critical Path
  22. 22. The Critical Path• The longest path throughout a projectnetwork• Has no slack (or float) therefore all activitieson the critical path must be completed asscheduled• End date will begin to slip – one day for eachday a critical activity is delayed
  23. 23. The Critical Path (cont’d)• Originally, the critical path considered onlylogical dependencies between terminalelements•Since then, it has been expanded to allow forthe inclusion of resources related to eachactivity , through processes called activity-basedresource assignments and resource leveling
  24. 24. What is CPM really?
  25. 25. The Critical Path (cont’d)• Also known as Critical Path Analysis (CPA) – is amathematically base algorithm for scheduling a set ofproject activities• An important tool for effective project management• Commonly used with all forms of projects includingconstruction, software development, researchprojects, product development, engineering, and plantmaintenance among others
  26. 26. The Critical Path (cont’d)• Essentially, to construct a model for a project,we need: WBS Time (duration) Dependencies
  27. 27. Terms you have to get used to...• Event: equivalent to a milestone – indicate the startand finish dates• Activity: element of work that must be accomplished• Duration: total time required• Effort: amount of work actually performed within theduration
  28. 28. Calender Scheduling• Calendar unit:- Time measurement for project schedule- The smallest unit of time- In hours, days, or weeks, years, months, shifts, evenin minutes• Take into account for issues such as:- For non-working time (weekend, holidays)- Resource constraint- Change risk- Cash flow- Logistics
  29. 29. Precedence Diagram Method (PDM)• Visual representation technique• Depicts the activities involved in a project• Also known as Project Network Diagrams• PDM helps:- Communicate- Identify missing activities- Identify critical activities- Create project schedule
  30. 30. Precedence Diagram Method (PDM) (cont’d) •Types of Dependencies: - Finish to Start (FS) : the predecessor must be completed before the successor can start Predecessor FS Successor 10 days 5 days Start Day: 1 Start Day: 10 Finish Day: 10 Finish Day: Start Day + 5
  31. 31. Precedence Diagram Method (PDM) (cont’d) •Types of Dependencies: - Start to Start (SS) : the successor can start at the earliest after the start of its immediate predecessor Predecessor 10 days SS Successor 5 days Start Day: 1 Start Day: 1 Finish Day: 10 Finish Day: 5 days after start day
  32. 32. Precedence Diagram Method (PDM) (cont’d) •Types of Dependencies: -Finish-Finish (FF): the successor will finish at the latest after its predecessor finished Predecessor 10 days FF Successor 5 days Start Day: 1 Finish Day: 10 Finish Day: 10 Start Day: 5 days before finish day
  33. 33. Precedence Diagram Method (PDM) (cont’d) •Types of Dependencies: -Start-Finish (SF) : the successor can finish only after the predecessor has started Predecessor 10 days SF Successor 5 days
  34. 34. Precedence Diagram Method (PDM) (cont’d) Multiple PDM Relationships: • Two PDM dependencies/relationships can be used together – combination • Having both SS and FF relationships in one activity SS =5 15 15 • B must be finished not later than 10 Activity A Activity B days after A is finished and starts after 5 days A started i.e. starts at day 10 FF=10
  35. 35. Precedence Diagram Method (PDM) (cont’d) Lag Time: • It’s a technique • Occurs when you add time to the start or finish of predecessor task • Causes a gap in timing • E.g.: FS dependency with 5 days lag = the successor cannot start until 5 days the predecessor has finished
  36. 36. Precedence Diagram Method (PDM) (cont’d) Lead Time: • It’s also a technique • Created when you subtract time from the start or finish of predecessor task • Causes overlap between two tasks • Allow acceleration of the successor activity • E.g.: FS dependency with 5 days lead= the successor can start 5 days before the predecessor has finished
  37. 37. Level of Detail• Should never have too little nor too much detail• Logical structure with appropriate level of detail isthe key to tracking throughout the project• Contents information required to manage the project– only that information• Rule of thumb:- 80 hour rule- if it make sense
  38. 38. Conventional Assumptions• Activity duration – scheduling done based onexpected or most likely time duration for each activity• Contingency allowance for activity duration• Availability of resources• Schedules to have low cost or ideally lowest cost
  39. 39. Summary•Network scheduling and PDM are techniquesto assist PM in scheduling – translating projectbrief into time schedule
  40. 40. Questions???  He who ask is a fool for five minutes, but he who does not ask is a fool forever.