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EM660 PROJECT MANAGEMENT Class 5
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Class 5 Agenda Chapter 12 Networks Chapter 13 Report Format
Chapter 12 Homework problems due 2/19/15 Problems and in book
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Change MS Projects to Work Saturdays
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Change MS Projects to Work Saturdays (cont.)
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Change MS Projects to Work Saturdays (cont.)
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MS Project Tutorial On Highlighting Critical Path
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Network Scheduling Techniques Chapter 12
Scheduling techniques (below) present masses of complex, technical, cost, & deadline data to management, teams and customers. 1) Gantt or bar charts 2) Milestone charts 3) Networks 4) PERT – Program Evaluation and Review Technique 5) ADM – Arrow Diagram Method (critical path method) 6) PDM – Precedence Diagram Method 7) GERT – Graphical Evaluation and Review Technique
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PERT CHART Program Evaluation and Review Technique
The Program (or Project) Evaluation and Review Technique, commonly abbreviated PERT, is a statistical tool, used in project management, that is designed to analyze and represent the tasks involved in completing a given project. First developed by the United States Navy in the 1950s, it is commonly used in conjunction with the critical path method (CPM).
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Activity on the Node
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Computing Drag Critical Path DRAG (Devaux's Removed Activity Gauge) is the amount of time that an activity on the critical path (i.e., the longest path through the project) is adding to the project’s duration or, alternatively, the amount of time by which the project completion would be pulled in by reducing a critical path activity’s duration to zero.
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Computing Drag(cont.) If an activity has nothing in parallel, its DRAG is equal to its duration. If an activity has other paths in parallel, its DRAG is whichever is less: its duration or the total float of the parallel activity with the least total float.
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Activity on the Arrows (we will only use activity on the nodes)
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Terminology PERT activity: the actual performance of a task which consumes time and requires resources (such as labor, materials, space, machinery). It can be understood as representing the time, effort, and resources required to move from one event to another. A PERT activity cannot be performed until the predecessor event has occurred. optimistic time (O): the minimum possible time required to accomplish a task, assuming everything proceeds better than is normally expected pessimistic time (P): the maximum possible time required to accomplish a task, assuming everything goes wrong (but excluding major catastrophes). most likely time (M): the best estimate of the time required to accomplish a task, assuming everything proceeds as normal. expected time (TE): the best estimate of the time required to accomplish a task, accounting for the fact that things don't always proceed as normal (the implication being that the expected time is the average time the task would require if the task were repeated on a number of occasions over an extended period of time).
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Terminology (cont.) TE = (O + 4M + P) ÷ 6float or slack is a measure of the excess time and resources available to complete a task. It is the amount of time that a project task can be delayed without causing a delay in any subsequent tasks (free float) or the whole project (total float). Positive slack would indicate ahead of schedule; negative slack would indicate behind schedule; and zero slack would indicate on schedule. critical path: the longest possible continuous pathway taken from the initial event to the terminal event. It determines the total calendar time required for the project; and, therefore, any time delays along the critical path will delay the reaching of the terminal event by at least the same amount. critical activity: An activity that has total float equal to zero. An activity with zero float is not necessarily on the critical path since its path may not be the longest. fast tracking: performing more critical activities in parallel crashing critical path: Shortening duration of critical activities
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Time Management NOTE: The PMP certification exam presents scheduling in the Time Management Chapter. NOTE: There is no such thing as project management software. MS Project is helpful for scheduling “what if” scenarios and status report functions. For this reason, this chapter involves a little manual math to understand MS Project.
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Advantages of Network Scheduling
Plan and predict Provide visibility Evaluate alternatives Identify slack Obtain facts Act a time network Identify critical paths Schedule risk analysis Basic report structure Reveal interdependencies Facilitate “what if” PERT & /CPM identify where the greatest effort should be placed to keep a project on schedule. Alternate plans may be developed & different scenarios tried, with the results presented in a well organized manner.
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Disadvantages of Network Scheduling
Time and labor intensive. Decision-making ability reduced Lacks functional ownership in measurements Lacks historical data for time-cost elements. Assumes unlimited resources. Requires too much detail.
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Terms EVENT – similar to milestones -when activities start or finish. ACTIVITY – links the events. DURATION – amount of time to finish activity. EFFORT – amount of actual work performed during duration (50% or 2 weeks in 1 month). CRITICAL PATH – The longest path; shows the shortest possible time to complete project.
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House II Homework-Draw Network on Board
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House III-Put in MS Projects
MS Project Gantt Chart
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Definitions
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Gantt Chart
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Slack Time
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Slack Time
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Tracking Gantt in MS Project
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Critical Path The Critical Path helps the project manager to:
Proves how long the project will take. Determines where to focus effort. Signals immediate action. Determines which items can be crashed and which can float. Note: There is no slack on the critical path and crashing non-critical path items won’t help improve delivery times.
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Slack of Task C
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Earliest Start/Latest Start
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Slack Slack is the amount of time a task can be delayed without delaying the project end date. Slack time = TLS – TES where TES is earliest start date and TLS is latest start date that won’t delay project. Slack lets you assign new employees to non-critical tasks, reallocate resources to shorten the overall project time, or gives the team some flexibility to juggle their schedules.
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Calculating Slack The critical path has no slack, so the ES and LS will be identical Do a forwards and backwards path to determine the ES and LS for non-critical tasks.
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Forward Pass ES(successor)=ES(current)+DUR(current)
Use the highest value on “join”
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Backward Pass LS(Predecessor)=LS(current)-DUR(Predecessor) Use the lowest value on “join”
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Show videos
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Forward Pass ES of A =0
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Forward Pass ESB =ESA+DURA
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Forward Pass Similarly for C & D
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Forward Pass ESE =Greatest of 7,13,16
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Backward Pass LSE = ESE
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Backward Pass LSF = LSE-DurF
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Backward Pass LSB = LSE-DurB
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Backward Pass LSC = LSE-DurC
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Backward Pass LSD = LSF-DurD
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Backward Pass LSA = LSD-DurA
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Backward Pass Slack=LS-ES
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Work Problem on Board
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Resource Allocation (p. 508)
Resource allocation involves moving resources from activities with slack to activities on the critical path, cutting overall project completion time.
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Crashing Crashing is making cost and schedule trade-offs to get the greatest schedule reduction for the least amount of cost. Crashing, by definition, almost always results in increased costs. If your estimated project completion date is after the customer’s desired date, you can ask for more time or crash the schedule and report the potential cost increase. It depends on which of your triple constraints is the primary driver.
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Crashing Example (Fig. 12-16)
Activity Normal Time Crash Time Time Savings Normal $ Crash $ Extra Cost Cost per Month A 4 2 10,000 14,000 4,000 2,000 B 6 5 1 30,000 42,500 12,500 C 8,000 9,500 1,500 D 12,000 18,000 6,000 E 7 40,000 52,000 F 3 20,000 29,000 9,000 3,000
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Crashing Example (Fig. 12-16)
Crash critical path activities only, lowest cost activity first! While activity C is the lowest cost per month ($1,500), it is not on the critical path. Start with activity A ($2,000 per month).
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Network Before Crashing Crash A for 2mos
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After Crashing A Crash F for 3mos
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After Crashing F
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After Crashing E Crash B for 1mo
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After Crashing B 1mo
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Project Cost versus Duration
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Crash House II Perform resource allocation and crash your House II for House III homework.
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Reducing Project Time (p.510)
Elimination of some parts of the project. Adding more resources (crashing). Substituting easier activities or components. Concurrent engineering (fast tracking). Shortening critical path activities (allocation). Increasing the number of work days (O.T.).
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Project Graphics Chapter 13
Good graphical displays are a prime means for tracking cost, schedule & performance (triple constraints). The information can be used for: Cutting project costs & reducing time scales. Coordinating and expediting planning. Eliminating idle time. Obtaining better subcontractor control. Better troubleshooting procedures. Allow more time for making better decisions.
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Reporting to an Audience
Upper management requires top level information, project costs & communication. At the operational level, stakeholders are looking for operating costs, performance and greater detail. The ability to communicate is a prerequisite for successful project management. The format of that communication depends on the audience.
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Gantt Charts Gantt charts list activities, their duration, schedule dates and progress. Pros include: simple to understand and easy to change. Cons include: No linkage or network interdependence, slack or critical paths.
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Milestone Charts Similar to Gantt charts but only show major events. Pros include: good tools for reporting to management and the customer. Milestone show when requirements are complete.
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Network Diagrams Critical path analysis, shows hidden linkages better than any other chart. Complex, multi-step projects are hard to resolve manually, computer software helps.
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Other charts…… Variation against a cost or time target or budget (performance measurements). Distribution of wealth (where is our money going?). Logic diagrams showing a process flow with no consideration of time or cost. Statistical Process Control Charts.
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Next Week Chapter 12 Homework problems due on 2/19/15, Problems and For House III crash House II and add resources and costs—remember, only crash tasks on the critical path and start with the lowest cost Quiz 2 on 2/26/15 Read Chapter 14 thru 16.
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