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PROJECT TIME MANAGEMENT
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IMPORTANCE Average time overrun on unsuccessful IT projects was 222 % of the original estimation. 1995 CHAOS Report It was reduced to 63% in 2000 2000 CHAOS Report One may massage the overrun of cost and scope Time passes no matter what happens on a project Time can be measured easily and simply
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Conflict intensity over the life of a project 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0.00 Project Formation Early Phase Middle Phase End Phase SchedulePriority ManpowerTech. option Procedure costPersonality Conflict Intensity Average Total Conflict
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MAIN PROCESS OF PTM Activity definition involves identifying the specific activities to produce the deliverables. Activity duration estimating involves estimating the work periods that are needed to complete individual activities. Activity sequencing involves identifying and documenting the relationships between activities. Schedule development involves activity estimating, sequencing and resources Schedule control involves controlling and managing changes to the project schedule
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ACTIVITY (TIME) ESTIMATION Define project type and Understand scope Reusable software resources Skill set needed Software project estimation Estimation of resource, schedule, and cost based on conditions defined by Program Plan and Engineering Plan. Project Type: Product: requirements from market Customized: RFP and proposal System Integration: RFP and proposal People Reusable Tools Project Resources
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ACTIVITY (TIME) ESTIMATION Problem-Based Estimation Line-Of-Code-Based (LOC) Function-Point-Based (FP) Process-Based Estimation History Record-Based
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ESTIMATION FAILURE Estimation of resource (human resource, reusable, skill set, domain expertise), schedule, and cost based on conditions defined by Program Plan and Engineering Plan. FAILED PROJECT IRADIUM Low Orbit, 66 satellites, 11 ground stations International: US, Russian, China, … Postmortem : Marketing Time to market Targeting (small customer group) Technology Management (estimation) Scope Size Payload Cross link In orbit link handset Ground stations
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WORK BREAKDOWN WORK BREAKDOWN STRUCTURE (WBS) Define product scope Identify function by decomposing scope Do while functions remain select a function assign all functions to sub functions list do while sub functions remain select a function if similar to historical function then use its estimation + change else if the function can be estimated then estimate else further decompose end if end do End do
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EXAMPLES OF ESTIMATION The CAD software will accept two- and three-dimensional geometric data from an engineer. The engineer will interact and control the CAD system through a user interface that will exhibit characteristics of good human/machine interface design. All geometric data and other supporting information will be maintained in a CAD database. Design analysis modules will be developed to produce the required output, which will be displayed on a variety of graphics devices. The software will be designed to control and interact with peripheral devices that include a mouse, digitizer, laser printer and plotter. User interface and control facilities (UICF) Two-dimensional geometric analysis (2DGA) Three-dimensional geometric analysis (3DGA) Database management (DBM) Computer graphics display facilities (GCDF) Peripheral control function (PFC) Design analysis modules (DAM) Computer-aided Design Application For Mechanical Component:
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LOC-BASED ESTIMATION FUNCTIONEST. LOC User interface and control facilities (UICF) Two-dimensional geometric analysis (2DGA) Three-dimensional geometric analysis (3DGA) Database management (DBM) Computer graphics display facilities (GCDF) Peripheral control function (PFC) Design analysis modules (DAM) 2,300 5,300 6,800 3,350 4,950 2,100 8,400 TOTAL33,200 ESTIMATED LOC = ( S optimistic + 4* S moderate + S pessimistic ) / 6 TOTAL PROJECT COST = $431,000 (54 person-month) Productivity=620 LOC/pm Salary=$8,000 Cost/LOC=$13
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FP-BASED ESTIMATION I Information domainOpt.LikelyPess.Est. Count WeightFP Count Number of inputs Number of outputs Number of inquiries Number of files Number of external interfaces 20 12 16 4 2 24 15 22 4 2 30 22 28 5 3 24 16 22 4 2 4 5 4 10 7 97 78 88 42 15 Count Total320 FP Count = Weight * ( FP optimistic + Weight* FP likely + FP pessimistic) / (Weight +2) FP estimated = Count Total * [0.65 + 0.01 * Σ(Fi)] = 375 TOTAL PROJECT COST = $461,000 (58 person-month) Productivity=6.5 FP/pm Salary=$8,000 Cost/FP=$1,230
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FP-BASED ESTIMATION II FactorValue (Fi) Backup and recovery4 Data communication2 Distributed processing0 Performance critical4 Existing operating environment3 On-line data entry4 Input transaction over multiple screen5 Master files updated on-line3 Information domain values complexity5 Internal processing complexity5 Code design for reuse4 Conversion/installation in design3 Multiple installation5 Application designed for change5 Complexity adjustment factor1.17
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HISTORICAL PROJECT METRICS Project Type: Product: requirements from market Customized: RFP and proposal System Integration: RFP and proposal Previous methods only estimate coding, not requirement, design, documentation, etc. Use historical project data (similar projects, metrics) 20 LOC/day (…), simple but efficient, hourly price of engineer (head count cost) including management cost + travel cost + per dine Requirement collection + analysis = implementation Product size estimation: brainstorm and bi-weekly estimation Type of projects: Cost + profit, Fixed price Difficult to estimate scope during bid process, to get the project, cut price and under estimate Application domain knowledge expertise
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ACTIVITY SEQUENCING PROJECT NETWORK DIAGRAM: a schematic display of the logical relationships among, or sequencing of, activities. Arrow diagramming method (ADM) Precedence diagramming method (PDM)
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ADM Activity-On-Arrow (AOA) 1 2 3 4 5 6 7 8 A=1 B=2 C=3 D=4 E=5 G=6 F=4 H=6 I=2 J=3 Critical Path (B-E-H-J) Is the series of activities that determine the earliest time by which the project can be completed. It is the longest path through the network diagram and has the least amount of slack (not the shortest path in the domain of transportation) Burst Merge
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Activity-On-Arrow (AOA) A=1 B=2 C=3 D=4 E=5 G=6 F=4 H=6 I=2 J=3 1 2 3 4 5 6 7 8 TASKSLACK A2 B0 C2 D2 E0 F7 G2 H0 I2 JO 5: A-D=5; B-E=7 6: A-D-H=11; B-E-H=13; B-F=6; C-G-I=11
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DUMMY ACTIVITY 1 2 3 4 5 6 7 10 A=1 B=2 C=3 D=4 E=5 G=6 F=4 H=6 I=2 J=3 8 K=11 9 L=1 Critical Path Method (CPM) Dummy activity
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PDM A B A B A B A B Finish-to-start (FS) Task B cannot start until task A finishes Start-to-start (SS) Task B cannot start until task A starts Finish-to-finish (FF) Task B cannot finish until task A finishes Start-to-finish (SF) Task B cannot finish until task A starts
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A Start: Finish: ID: 1 C Start: Finish: ID: 3 D Start: Finish: ID: 4 E Start: Finish: ID: 5 B Start: Finish: ID: 2
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A B C D E F G H I J SMTWTFSSMTWTFSSMTWTFSSM Gantt Chart
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Techniques for shortening schedule Crashing: making cost and schedule trade-offs to obtain the greatest amount of schedule compression for the least incremental cost. 123 1 3a 43b 3c 2 A=5B=9 A=5 B1=4 B2=3 B3=2 B1’=1 B3’=2 In preparing critical path diagram for a project, usually resource is not considered. You may have to consider resources when shortening schedule.
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Techniques for shortening schedule Fast tracking: doing activities in parallel that you would normally do in sequence. 123 1 3 4 2 A=5B=9 A’=0 B=9 C=6 4 A=5
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CRITICAL CHAIN SCHEDULING Avoid multitasking Multitasking: when a resource works on more than one task/project at a time. TASK 1TASK 3 10 days Task 2 completed Task 3 completed Task 1Task 2Task 3Task 1Task 2Task 3 10 days 5 days Task 1 completed Task 2 completed Task 3 completed +△+△ +△+△ +△+△ TASK 2 Task 1 completed
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CRITICAL CHAIN SCHEDULING Avoid individual buffer Individual buffers: when activity duration estimations are done by individuals, safety (buffer) is usually included for each estimation. FB Proj. buffer Add project buffer and feeding buffer (FB)
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CRITICAL CHAIN SCHEDULING Probabilistic time estimates Optimistic time + 4xmost likely time + pessimistic time = 6 Weighted average
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