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Project Scheduling A. A. Elimam FinishStart
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Project Scheduling Need to plan and control large/time consuming projects
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Projects Characteristics n Projects are unique n Time Estimation Difficulty n Control Decomposition into smaller tasksDecomposition into smaller tasks Responsibility of a task given to a specific individualResponsibility of a task given to a specific individual
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Project Management: Stages 1.Define:Describe goal or Final outcome of Project 2.Plan:Identify tasks / resources / time 3.Execute / Control: Time-cost Trade-off
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Activity The smallest unit of work effort consuming both time and resources that the project manager can schedule and control.
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Precedence Relationship A sequencing constraint between interrelated activities by which one activity cannot start until a preceeding activity has been completed.
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Schedule A plan that sets priorities, determines start and finish times, and allocates resources to accomplish the activities.
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Examples Q Constructing a building or amusement park Q Constructing a road, dam, or oil pipeline Q Renovating a blighted urban area Q Developing a prototype for a new airplane Q Installing a large computer system Q Introducing a new product Q Organizing a state fair Q Redesigning an office layout
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Measuring Success of a project ConformanceTimeBudget
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Basic Questions 1.Project completion time? 2.Critical activities? 3.Activities that can be delayed? How Long? 4.Starting / ending time of each activity? 5.Range of $’s spent on project? 6.Time-cost trade-off
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Project Management Basic Steps i.Describe project ii.Draw a network diagram iii.Provide time estimates iv.Analyze network v.Develop project plan vi.Update project plan
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i. Describe project n Activities / precedence n end points
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ii. Draw a network diagram AOA: Arcs: Activities Nodes: Event AOA: Arcs: Activities Nodes: Event AON: Nodes: ActivitiesArcs: Sequence AON: Nodes: ActivitiesArcs: Sequence
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AOA and AON relationships 1 2 A B C 3 4 (a) AOA approach: Event 4 cannot take place until activities A, B and C have been completed. (b) AON approach: Activity C cannot take place until activities A and B completed. A B C Event Activity Implies time and resource consumption Software
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Activity Relationships Activity Relationship AOAAON
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Activity Relationships Activity Relationship S precedes T, which precedes U. AOAAON 12 S 3 T 4 U STU
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Activity Relationships Activity Relationship S and T must be completed before U can be started. AOAAON S T U 1 2 3 T S 4 U
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Activity Relationships Activity Relationship T and U cannot begin until S has been completed. AOAAON T U S 3 4 1 T U 2 S
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Activity Relationships Activity Relationship U and V cannot begin until both S and T have been completed. AOAAON 1 2 4 5 U V S T 3 S T U V
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Activity Relationships Activity Relationship U cannot begin until both S and T have been completed; V cannot begin until T has been completed. AOAAON S T U V 13 Dummy 5 246 SU TV
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Activity Relationships Activity Relationship T and U cannot begin until S has been completed; V cannot begin until both T and U have been completed. AOAAON 124 3 ST 5 V UDummy STV U
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iii. Provide Time Estimates n Deterministic CPM Critical Path Method or Probabilistic PERT Probabilistic PERT Program Evaluation and Review Technique then CPM
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iv. Analyze Network n Identify critical path (CP) and activities on it n Estimate probability of completing project on time n Explore time-cost trade-off
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v. Develop project plan n Schedule each activity (particularly on CP) Monitor actual planned. Monitor actual planned.
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vi. Update project plan n Adjust schedule on the basis of actuals
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St. Adolf’s Hospital Immediate ActivityDescriptionPredecessor(s) ASelect administrative and medical staff. BSelect site and do site survey. CSelect equipment. DPrepare final construction plans and layout. EBring utilities to the site. FInterview applicants and fill positions in nursing, support staff, maintenance, and security. GPurchase and take delivery of equipment. HConstruct the hospital. IDevelop and information system. JInstall the equipment. KTrain nurses and support staff.
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St. Adolf’s Hospital Immediate ActivityDescriptionPredecessor(s) ASelect administrative and medical staff.— BSelect site and do site survey.— CSelect equipment.A DPrepare final construction plans and layout.B EBring utilities to the site.B FInterview applicants and fill positions in nursing, support staff, maintenance, and security.A GPurchase and take delivery of equipment.C HConstruct the hospital.D IDevelop and information system.A JInstall the equipment.E,G,H KTrain nurses and support staff.F,I,J
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St. Adolf’s Hospital Immediate ActivityDescriptionPredecessor(s) ASelect administrative and medical staff.— BSelect site and do site survey.— CSelect equipment.A DPrepare final construction plans and layout.B EBring utilities to the site.B FInterview applicants and fill positions in nursing, support staff, maintenance, and security.A GPurchase and take delivery of equipment.C HConstruct the hospital.D IDevelop and information system.A JInstall the equipment.E,G,H KTrain nurses and support staff.F,I,J AON Network A Start
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St. Adolf’s Hospital Immediate ActivityDescriptionPredecessor(s) ASelect administrative and medical staff.— BSelect site and do site survey.— CSelect equipment.A DPrepare final construction plans and layout.B EBring utilities to the site.B FInterview applicants and fill positions in nursing, support staff, maintenance, and security.A GPurchase and take delivery of equipment.C HConstruct the hospital.D IDevelop and information system.A JInstall the equipment.E,G,H KTrain nurses and support staff.F,I,J AON Network A B Start
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St. Adolf’s Hospital Immediate ActivityDescriptionPredecessor(s) ASelect administrative and medical staff.— BSelect site and do site survey.— CSelect equipment.A DPrepare final construction plans and layout.B EBring utilities to the site.B FInterview applicants and fill positions in nursing, support staff, maintenance, and security.A GPurchase and take delivery of equipment.C HConstruct the hospital.D IDevelop and information system.A JInstall the equipment.E,G,H KTrain nurses and support staff.F,I,J AON Network A C B Start
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St. Adolf’s Hospital Immediate ActivityDescriptionPredecessor(s) ASelect administrative and medical staff.— BSelect site and do site survey.— CSelect equipment.A DPrepare final construction plans and layout.B EBring utilities to the site.B FInterview applicants and fill positions in nursing, support staff, maintenance, and security.A GPurchase and take delivery of equipment.C HConstruct the hospital.D IDevelop and information system.A JInstall the equipment.E,G,H KTrain nurses and support staff.F,I,J AON Network A C DB Start
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St. Adolf’s Hospital Immediate ActivityDescriptionPredecessor(s) ASelect administrative and medical staff.— BSelect site and do site survey.— CSelect equipment.A DPrepare final construction plans and layout.B EBring utilities to the site.B FInterview applicants and fill positions in nursing, support staff, maintenance, and security.A GPurchase and take delivery of equipment.C HConstruct the hospital.D IDevelop and information system.A JInstall the equipment.E,G,H KTrain nurses and support staff.F,I,J AON Network A C D E B Start
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St. Adolf’s Hospital Immediate ActivityDescriptionPredecessor(s) ASelect administrative and medical staff.— BSelect site and do site survey.— CSelect equipment.A DPrepare final construction plans and layout.B EBring utilities to the site.B FInterview applicants and fill positions in nursing, support staff, maintenance, and security.A GPurchase and take delivery of equipment.C HConstruct the hospital.D IDevelop and information system.A JInstall the equipment.E,G,H KTrain nurses and support staff.F,I,J AON Network AF C D E B Start
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St. Adolf’s Hospital Immediate ActivityDescriptionPredecessor(s) ASelect administrative and medical staff.— BSelect site and do site survey.— CSelect equipment.A DPrepare final construction plans and layout.B EBring utilities to the site.B FInterview applicants and fill positions in nursing, support staff, maintenance, and security.A GPurchase and take delivery of equipment.C HConstruct the hospital.D IDevelop and information system.A JInstall the equipment.E,G,H KTrain nurses and support staff.F,I,J AON Network AF CG D E B Start
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St. Adolf’s Hospital Immediate ActivityDescriptionPredecessor(s) ASelect administrative and medical staff.— BSelect site and do site survey.— CSelect equipment.A DPrepare final construction plans and layout.B EBring utilities to the site.B FInterview applicants and fill positions in nursing, support staff, maintenance, and security.A GPurchase and take delivery of equipment.C HConstruct the hospital.D IDevelop and information system.A JInstall the equipment.E,G,H KTrain nurses and support staff.F,I,J AON Network AF CG D E HB Start
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St. Adolf’s Hospital Immediate ActivityDescriptionPredecessor(s) ASelect administrative and medical staff.— BSelect site and do site survey.— CSelect equipment.A DPrepare final construction plans and layout.B EBring utilities to the site.B FInterview applicants and fill positions in nursing, support staff, maintenance, and security.A GPurchase and take delivery of equipment.C HConstruct the hospital.D IDevelop and information system.A JInstall the equipment.E,G,H KTrain nurses and support staff.F,I,J AON Network
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St. Adolf’s Hospital Immediate ActivityDescriptionPredecessor(s) ASelect administrative and medical staff.— BSelect site and do site survey.— CSelect equipment.A DPrepare final construction plans and layout.B EBring utilities to the site.B FInterview applicants and fill positions in nursing, support staff, maintenance, and security.A GPurchase and take delivery of equipment.C HConstruct the hospital.D IDevelop and information system.A JInstall the equipment.E,G,H KTrain nurses and support staff.F,I,J AON Network
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St. Adolf’s Hospital Immediate ActivityDescriptionPredecessor(s) ASelect administrative and medical staff.— BSelect site and do site survey.— CSelect equipment.A DPrepare final construction plans and layout.B EBring utilities to the site.B FInterview applicants and fill positions in nursing, support staff, maintenance, and security.A GPurchase and take delivery of equipment.C HConstruct the hospital.D IDevelop and information system.A JInstall the equipment.E,G,H KTrain nurses and support staff.F,I,J AON Network
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St. Adolf’s Hospital Immediate ActivityDescriptionPredecessor(s) ASelect administrative and medical staff.— BSelect site and do site survey.— CSelect equipment.A DPrepare final construction plans and layout.B EBring utilities to the site.B FInterview applicants and fill positions in nursing, support staff, maintenance, and security.A GPurchase and take delivery of equipment.C HConstruct the hospital.D IDevelop and information system.A JInstall the equipment.E,G,H KTrain nurses and support staff.F,I,J AON Network
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St. Adolf’s Hospital Immediate ActivityDescriptionPredecessor(s) ASelect administrative and medical staff.— BSelect site and do site survey.— CSelect equipment.A DPrepare final construction plans and layout.B EBring utilities to the site.B FInterview applicants and fill positions in nursing, support staff, maintenance, and security.A GPurchase and take delivery of equipment.C HConstruct the hospital.D IDevelop and information system.A JInstall the equipment.E,G,H KTrain nurses and support staff.F,I,J Completion Time FinishStart A 12 C 10 G 35 H 40 D 10 E 24 J 4 K 6 F 10 I 15 B 9
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 I 15 F 10 Earliest Start and Earliest Finish Times
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 I 15 F 10 Earliest Start and Earliest Finish Times Earliest start time
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 Earliest Start and Earliest Finish Times Earliest start time Earliest finish time
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 0 9 Earliest Start and Earliest Finish Times
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 9 33 0 9 9 19 Earliest Start and Earliest Finish Times
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 9 33 0 9 9 19 12 22 Earliest Start and Earliest Finish Times
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 19 59 9 33 0 9 9 19 12 22 Earliest Start and Earliest Finish Times
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 22 57 19 59 9 33 0 9 9 19 12 22 Earliest Start and Earliest Finish Times
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 22 57 59 6319 59 9 33 0 9 9 19 12 22 Earliest Start and Earliest Finish Times
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 63 69 22 57 59 6319 59 9 33 0 9 9 19 12 22 Earliest Start and Earliest Finish Times
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 63 69 22 57 59 6319 59 9 33 0 9 9 19 12 22 Latest Start and Latest Finish Times
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St. Adolf’s Hospital Latest Start and Latest Finish Times FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 63 69 22 57 59 6319 59 9 33 0 9 9 19 12 22 63 69 Latest finish time
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St. Adolf’s Hospital Latest Start and Latest Finish Times FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 63 69 22 57 59 6319 59 9 33 0 9 9 19 12 22 63 69 Latest start time Latest finish time
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 63 69 22 57 59 6319 59 9 33 0 9 9 19 12 22 48 63 53 63 63 69 59 63 Latest Start and Latest Finish Times
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 63 69 22 57 59 6319 59 9 33 0 9 9 19 12 22 48 63 53 63 63 69 24 59 19 59 35 59 59 63 Latest Start and Latest Finish Times
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 63 69 22 57 59 6319 59 9 33 0 9 9 19 12 22 48 63 53 63 63 69 14 24 24 59 9 19 19 59 35 59 59 63 Latest Start and Latest Finish Times
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 63 69 22 57 59 6319 59 9 33 0 9 9 19 12 22 48 63 2 14 53 63 63 69 14 24 24 59 0 9 9 19 19 59 35 59 59 63 Latest Start and Latest Finish Times
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 63 69 22 57 59 6319 59 9 33 0 9 9 19 12 22 48 63 2 14 53 63 63 69 14 24 24 59 0 9 9 19 19 59 35 59 59 63 Activity Slack Analysis
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 63 69 22 57 59 6319 59 9 33 0 9 9 19 12 22 48 63 2 14 53 63 63 69 14 24 24 59 0 9 9 19 19 59 35 59 59 63 Activity Slack Analysis LS - ES = S
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 63 69 22 57 59 6319 59 9 33 0 9 9 19 12 22 48 63 2 14 53 63 63 69 14 24 24 59 0 9 9 19 19 59 35 59 59 63 Activity Slack Analysis LS - ES = S 63 - 63 = 0
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 63 69 22 57 59 6319 59 9 33 0 9 9 19 12 22 48 63 2 14 53 63 63 69 14 24 24 59 0 9 9 19 19 59 35 59 59 63 Activity Slack Analysis LF - EF = S 69 - 69 = 0
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 63 69 22 57 59 6319 59 9 33 0 9 9 19 12 22 48 63 2 14 53 63 63 69 14 24 24 59 0 9 9 19 19 59 35 59 59 63 Activity Slack Analysis 0
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 63 69 22 57 59 6319 59 9 33 0 9 9 19 12 22 48 63 2 14 53 63 63 69 14 24 24 59 0 9 9 19 19 59 35 59 59 63 Activity Slack Analysis 0000 0
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St. Adolf’s Hospital FinishStart A 12 K6K6 C 10 G 35 J4J4 H 40 B9B9 D 10 E 24 0 12 I 15 F 10 12 27 12 22 63 69 22 57 59 6319 59 9 33 0 9 9 19 12 22 48 63 2 14 53 63 63 69 14 24 24 59 0 9 9 19 19 59 35 59 59 63 Activity Slack Analysis 0000 2 2 26 41 36 0 2
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St. Adolf’s Hospital FinishStart A 12 C 10 G 35 E 24 0 12 I 15 F 10 12 27 12 22 22 57 9 33 12 22 48 63 2 14 53 63 14 24 24 59 35 59 0000 2 2 26 41 36 0 2 B9B9 0 9 D 10 9 19 H 40 19 59 J4J4 59 63 K6K6 63 69 Critical Path
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Probabilistic Time Estimates
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Time Probability
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Probabilistic Time Estimates Mean mab Time Probability
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Probabilistic Time Estimates Mean Time Probability abm 3s
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St. Adolf’s Hospital Probabilistic Time Estimates
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St. Adolf’s Hospital Activity B Most OptimisticLikelyPessimistic (a)(m)(b) 7815 Probabilistic Time Estimates
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St. Adolf’s Hospital Activity B Most OptimisticLikelyPessimistic (a)(m)(b) 7815 Probabilistic Time Estimates t e = = 9 weeks 7 + 4(8) + 15 6
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St. Adolf’s Hospital Activity B Most OptimisticLikelyPessimistic (a)(m)(b) 7815 Probabilistic Time Estimates t e = = 9 weeks 7 + 4(8) + 15 6 2 = = 1.78 ( ) 15 - 7 6 2
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St. Adolf’s Hospital OptimisticLikelyPessimisticExpectedVariance Activity(a)(m)(b)Time (t e )( 2 ) Time Estimates (wk)Activity Statistics
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St. Adolf’s Hospital OptimisticLikelyPessimisticExpectedVariance Activity(a)(m)(b)Time (t e )( 2 ) Time Estimates (wk)Activity Statistics A111213120.11 B781591.78 C51015102.78 D8916101.78 E142530247.11 F6918104.00 G253641357.11 H354045402.78 I101328159.00 J121545.44 K56760.11
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St. Adolf’s Hospital Probabilities Critical Path = B - D - H - J - K T = 72 days T E = 69 days
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St. Adolf’s Hospital 2 = (variances of activities) z = T - T E 2 Probabilities Critical Path = B - D - H - J - K T = 72 days T E = 69 days
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St. Adolf’s Hospital 2 = (variances of activities) z = T - T E 2 2 = 1.78 + 1.78 + 2.78 + 5.44 + 0.11 = 11.89 Probabilities Critical Path = B - D - H - J - K T = 72 days T E = 69 days
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St. Adolf’s Hospital 2 = (variances of activities) z = T - T E 2 2 = 1.78 + 1.78 + 2.78 + 5.44 + 0.11 = 11.89 z = 72 - 69 11.89 Probabilities Critical Path = B - D - H - J - K T = 72 days T E = 69 days
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St. Adolf’s Hospital 2 = (variances of activities) z = T - T E 2 2 = 1.78 + 1.78 + 2.78 + 5.44 + 0.11 = 11.89 z = = 0.87 72 - 69 11.89 Probabilities Critical Path = B - D - H - J - K T = 72 days T E = 69 days
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St. Adolf’s Hospital 2 = (variances of activities) z = T - T E 2 2 = 1.78 + 1.78 + 2.78 + 5.44 + 0.11 = 11.89 z = = 0.87 72 - 69 11.89 Probabilities Critical Path = B - D - H - J - K T = 72 days T E = 69 days From Appendix 2 P z =.8078 .81
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St. Adolf’s Hospital Project duration (weeks) 6972 Probability of meeting the schedule is 0.8078 Length of critical path Normal distribution: Mean = 69 weeks; = 3.45 weeks Probability of exceeding 72 weeks is 0.1922
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St. Adolf’s Hospital 2 = (variances of activities) z = T - T E 2 2 = 0.11 + 2.78 + 7.11 + 5.44 + 0.11 = 15.55 z = = 1.27 72 - 67 15.55 Probabilities Path = A - C - G - J - K T = 72 days T E = 67 days From Appendix 2 P z =.8980 .90
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St. Adolf’s Hospital AF I CGFinish D E HBJ K Start Project duration (weeks) 6769 Probability path B- D-H-J-K is less than 67 weeks Normal distribution for path B-D-H-J-K: Mean = 69 weeks; = 3.45 weeks Probability path A-C-G-J-K is more than 69 weeks Normal distribution for path A-C-G-J-K: Mean = 67 weeks; = 3.94 weeks
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St. Adolf’s Hospital 8000 — 7000 — 6000 — 5000 — 4000 — 3000 — 0 — Direct cost (dollars) |||||| 567891011
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St. Adolf’s Hospital 8000 — 7000 — 6000 — 5000 — 4000 — 3000 — 0 — Direct cost (dollars) Crash cost (CC) Normal cost (NC) |||||| 567891011 Time (weeks) (Crash time)(Normal time)
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St. Adolf’s Hospital 8000 — 7000 — 6000 — 5000 — 4000 — 3000 — 0 — Direct cost (dollars) Crash cost (CC) Linear cost assumption Normal cost (NC) |||||| 567891011 Time (weeks) (Crash time)(Normal time)
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St. Adolf’s Hospital 8000 — 7000 — 6000 — 5000 — 4000 — 3000 — 0 — Direct cost (dollars) 5200 Crash cost (CC) Linear cost assumption Normal cost (NC) Estimated costs for a 2-week reduction, from 10 weeks to 8 weeks |||||| 567891011 Time (weeks) (Crash time)(Normal time)
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St. Adolf’s Hospital Minimum Cost Schedule A-I-K:33 weeksB-D-H-J-K:69 weeks A-F-K:28 weeksB-E-J-K:43 weeks A-C-G-J-K:67 weeks Total cost = $2,624,000 Indirect costs = $8,000/week Penalty cost = $20,000/week after week 65
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St. Adolf’s Hospital Minimum Cost Schedule A-I-K:33 weeksB-D-H-J-K:69 weeks A-F-K:28 weeksB-E-J-K:43 weeks A-C-G-J-K:67 weeks Total cost = $2,624,000 Indirect costs = $8,000/week Penalty cost = $20,000/week after week 65
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St. Adolf’s Hospital Minimum Cost Schedule A-I-K:33 weeksB-D-H-J-K:69 weeks A-F-K:28 weeksB-E-J-K:43 weeks A-C-G-J-K:67 weeks Total cost = $2,624,000 Indirect costs = $8,000/week Penalty cost = $20,000/week after week 65 Critical Path B-D-H-J-K: 69 weeks Crash Activity J by 3 weeks @ $1,000/week
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St. Adolf’s Hospital Minimum Cost Schedule A-I-K:33 weeksB-D-H-J-K:69 weeks A-F-K:28 weeksB-E-J-K:43 weeks A-C-G-J-K:67 weeks Total cost = $2,624,000 Indirect costs = $8,000/week Penalty cost = $20,000/week after week 65 Critical Path B-D-H-J-K: 69 weeks Crash Activity J by 3 weeks @ $1,000/week 3($28,000) - 3($1,000) = $81,000
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St. Adolf’s Hospital Minimum Cost Schedule A-I-K:33 weeksB-D-H-J-K:69 weeks A-F-K:28 weeksB-E-J-K:43 weeks A-C-G-J-K:67 weeks Total cost = $2,624,000 Indirect costs = $8,000/week Penalty cost = $20,000/week after week 65 Critical Path B-D-H-J-K: 66 weeks Crash Activity J by 3 weeks @ $1,000/week 3($28,000) - 3($1,000) = $81,000 $2,624,000 - $81,000 = $2,543,000
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St. Adolf’s Hospital Minimum Cost Schedule A-I-K:33 weeksB-D-H-J-K:69 weeks A-F-K:28 weeksB-E-J-K:43 weeks A-C-G-J-K:67 weeks Total cost = $2,624,000 $2,543,000 Indirect costs = $8,000/week Penalty cost = $20,000/week after week 65 Critical Path B-D-H-J-K: 66 weeks Crash Activity J by 3 weeks @ $1,000/week 3($28,000) - 3($1,000) = $81,000 $2,624,000 - $81,000 = $2,543,000
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St. Adolf’s Hospital FinishStart A 12 C 10 G 35 E 24 0 12 I 15 F 10 12 27 12 22 22 57 9 33 12 22 48 63 2 14 53 63 14 24 24 59 35 59 0000 2 2 26 41 36 0 2 B9B9 0 9 D 10 9 19 H 40 19 59 J4J4 59 63 K6K6 63 69
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Precedence for Playground activities CodeActivity DescriptionTimeImmediate Name (days)Predecessors APlanningFind location, determine resource requirements20None BPurchasingRequisition lumber and sand60Planning (A) CExcavationDig and grade100Planning (A) DSawingSaw lumber into appropriate sizes30Purchasing (B) EPlacementPosition lumber in correct locations20Sawing, excavation (D,C) FAssemblyNail lumber together`10Placement (E) GInfillPut sand in and under equipment20Assembly (F) HOutfillPut dirt around equipment10Assembly( F) IDecorationLandscape, paint30Infill, outfill (G,H)
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Playground Project APlanning BPurchasing DSawing EPlacement CExcavation FAssembly HOutfill IDecoration GInfill
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A Planning B Purchasing D Sawing E Placement C Excavation F Assembly H Outfill I Decoration G Infill ES=20EF=80ES=80EF=110 ES=120EF=140 ES=20EF=120 ES=140EF=150 ES=170EF=200 ES=150EF=160 ES=150EF=170 ES=0EF=20 Two pass approach Forward Pass
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Playground Project A Planning B Purchasing D Sawing E Placement C Excavation F Assembly H Outfill I Decoration G Infill ES=20EF=80LF=90LS=30ES=80EF=110LF=120LS=90 ES=120EF=140LF=140LS=120 ES=20EF=120LF=120LS=20 ES=140EF=150LF=150LS=140 ES=170EF=200LF=200LS=170 ES=150EF=160LF=170LS=160 ES=150EF=170LF=170LS=150 ES=0EF=20LF=20LS=0 Two pass approach Backward Pass
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Playground Project A Planning B Purchasing D Sawing E Placement C Excavation F Assembly H Outfill I Decoration G Infill ES=20EF=80LF=90LS=30 S B =10 ES=80EF=110LF=120LS=90 S D =10 ES=120EF=140LF=140LS=120 S E =0 ES=20EF=120LF=120LS=20 S C =0 ES=140EF=150LF=150LS=140 S F =0 ES=170EF=200LF=200LS=170 S I =0 ES=150EF=160LF=170LS=160 S H =10 ES=150EF=170LF=170LS=150 S G =0 ES=0EF=20LF=20LS=0 S A =0 Two pass approach
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Playground Project A Planning B Purchasing D Sawing E Placement C Excavation F Assembly H Outfill I Decoration G Infill ES=20EF=80LF=90LS=30 S B =10 ES=80EF=110LF=120LS=90 S D =10 ES=120EF=140LF=140LS=120 S E =0 ES=20EF=120LF=120LS=20 S C =0 ES=140EF=150LF=150LS=140 S F =0 ES=170EF=200LF=200LS=170 S I =0 ES=150EF=160LF=170LS=160 S H =10 ES=150EF=170LF=170LS=150 S G =0 ES=0EF=20LF=20LS=0 S A =0 Critical Path
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Cost-time relationships analysis 567891011 Activity time duration (weeks) Total direct activity cost ($) 8,0007,0006,0005,0004,0003,000 Crash time, cost Linear cost assumption Estimated costs for a 2-week reduction Normal time, cost Hypothetical actual cost curve NT NC CT CC Cost to crash per week = CC - NC NT - CT
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Limitations of PERT / CPM n project activities must be clearly defined, independent, and stable in their relationships n precedence relationships must be specified and networked together n time activities in PERT are assumed to follow the beta probability distribution this may be difficult to verify n time estimates tend to be subjective, and are subject to fudging by managers n there is inherent danger in too much emphasis being placed on the critical path
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Resource Limitations 2B52B5 4C24C2 5A15A1 6D36D3 Activity time in days Workers required per day Finish Start 3E33E3
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123456789101112 Day Activity A B C D E Resource Requirements Resource Limitations Gantt Charts
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