1、Engineering Planning and Project ManagementLecture 6Project Time ManagementExample from Industry Motorola(Telecommunications Engineering)lReview the short text provided from P.103-104 of PM Best PracticeslBreak into your groups for a few minutes and discuss the following questions preparing a respon
2、se which you may be asked to present.lQuestion 1:One of the bullet items referenced in Motorolas development of formal practices is the planning and tracking of resources.Besides personnel,give a realistic example of what else Motorola might track.lQuestion 2:What do you think“complete”project sched
3、uling would imply?Give examples of how you would integrate it to your project management strategy if you were a Motorola PM.Project SchedulinglFirst you need to generate the Work Breakdown Structure(WBS)for the project as demonstrated.lFrom the WBS,you need to generate the Network Activity Diagram f
4、or the project commonly referred to as the Network Diagram.The Rules for creating Network Activity Diagrams1.Some determination of activity precedence ordering must be done prior to creating the network.2.Network diagrams usually flow from left to right.3.An activity cannot begin until all preceding
5、 connected activities have been completed.4.Arrows on networks indicate precedence and logical flow.Arrows can cross over each other,although it is helpful for claritys sake to limit this effect when possible.5.Each activity should have a unique identifier associated with it(number,letter,code,etc.)
6、.6.Looping,or recycling through activities,is not permitted.7.Although not required,it is common to start a project from a single beginning node.A single node point also is typically used as a project end indicator.Key Scheduling Terminology-simplifiedlScope The work content and products of a projec
7、t.lWork Breakdown Structure(WBS)A task oriented family tree of activities that organizes,defines,and graphically displays the total work to be accomplished in order to achieve the final objectives of the project.lWork Package A deliverable at the lowest level of the work breakdown structure.lProject
8、 Network Diagram Any schematic display of the logical relationships of project activities.lPath A sequence of activities defined by the project network logic.lEarly Start Date(ES)The earliest possible date on which the uncompleted portions of an activity can be completed.lLate Start Date(LS)The late
9、st possible date that an activity may begin without delaying a specified milestone.Key Scheduling Terminology simplified(cont.)lForward Pass Network calculations that determine the earliest start/finish time for each activity.lBackward Pass Calculation of late finish times for all uncompleted networ
10、k activities.lEvent A point in time when an activity is either started or completed.lNode One or more defining points of a network.lPredecessors Those activities that must be completed prior to a later activity in the network.lSuccessors Activities that cannot be started until previous actions have
11、been completed.lMerge Activity An activity with 2 or more immediate successor activities flowing into it.Key Scheduling Terminology simplified(cont.)lBurst Activity An activity with 2 or more immediate successor activities flowing out from it.lFloat(Slack)the amount of time an activity may be delaye
12、d from its early start without delaying the finish of the project.lCritical Path The path through the project network with the longest duration.lCritical Path Method A network analysis technique used to determine which sequence of activities(which path)has the least amount of scheduling flexibility
13、and therefore will most likely determine when the project can be completed.lResource Limited Schedule A project schedule whose start and finish dates reflect expected resource availability.lProgram Evaluation and Review Tool(PERT)An event and probability based network analysis system generally used
14、in projects where activities and their durations are difficult to define.Labels for Activity NodesSeries/Parallel ActivitiesActivities Merge/BurstCreating a Project Network Activity Diagram-ExampleActivity NetworkActivity Duration Estimate Beta EstimateConstructing the Critical PathProject Activity
15、Network Showing Project DurationsRules when using the Forward PassActivity Network with Forward PassRules when using the Backward PassActivity Network with Backward PassCompleted Network Activity Diagramwith Critical Path and Slack Times CalculatedCritical Path in boldNetwork Activity Diagram exampl
16、e that Illustrates Laddering techniqueLaddering is typically used in situations where one might expect a progressive loop in the project activities such as commonly found in software development.Network Activity Diagram example that Illustrates Hammocking techniqueHammocking activities can be added
17、as summaries for diagram segments of series activities.They can for managerial explanation for example,replace the series of activities by which they are bounded.This allows for a smaller diagram.Steps to Reduce the Critical PathResource LevelingSometimes it is necessary to make the critical path of
18、 the project actually longer!This technique is called resource leveling.While resource leveling does not by definition mandate lengthening the critical path it almost always does.Resource leveling is carried out when a project resource must be used to address schedule activities that need to be perf
19、ormed to meet specified delivery dates,or to address a situation where shared or critical resources are only available at certain times or in limited quantities.Resource leveling is also used to keep selected resources at constant levels during specific times of the project work.The Impact of Resour
20、ce Leveling Network diagram shown prior to resource leveling being carried outThe Impact of Resource Leveling showing the level adjustment for designthe critical path isstretched 2 daysActivity Duration EstimatinglThere are several methods:lExpert judgment estimating Guided by historical information
21、 this can be used whenever possible.lAnalogous estimating A method of estimating that employs using a similar schedule activity from a previous project as the basis for establishing the likely duration of a future schedule activity.lParametric estimating the quantity of work multiplied by the produc
22、tivity rate.For example labor hours to draw times number of hours,or cable installation in meters of cable times labor hours per meter.lThree point method PERTlReserve analysis estimating An output of risk analysis,it can be employed to add empty buffers in project timing to deal with risk as part o
23、f a contingency plan.Lags in Precedence RelationshipslThere are 4 common logic relationships between tasks:1)Finish to Start2)Finish to Finish3)Start to Start4)Start to FinishFinish to StartFinish to Finish31S33Plumbing233T36HVAC336U42Interior Constructing630R36Wiring60A6Spec design66B11Design Check
24、515C22Blueprinting7Lag 4Start to StartStart to Finish31S33Plumbing233T36HVAC336U42Interior Constructing633R39Wiring6Lag 331S33Plumbing233T36HVAC336U42Interior Constructing630R36Wiring6Lag 3Gantt chartslDeveloped by Harvey Gantt in 1917,they are another extremely useful tool for creating showing a pr
25、oject network.lGantt charts establish a time-phased network,which links project activities to a project scheduleGantt ChartsWhen they are linked to a project schedule,they can be used to track the progress of the project against its plan.Some of the benefits of Gantt Charts are:a)they are easy to re
26、ad and comprehendb)they identify the project network coupled with the schedulec)they allow for updating and project controld)they are useful for assigning resources to taskse)they are also easy to create.IDTask NameDuration1A5 days2B4 days3C5 days4D6 days5E6 days6F6 days7G4 days8H7 days9I5 days10J3
27、days11K5 daysMTWTFSSMTWTFSSMTWTFSSMTWTFSSMTWTFSSMTWTF17 Dec 0724 Dec 0731 Dec 0707 Jan 0814 Jan 0821 Jan 08Gantt Chart Table versionGantt Chart MS Project versionActivityA(X X X X)B(X X X X X X X X)C(X X)D(X X X X X X X X)E(X X X X)F(X X X)G(X X X X X X X X X X X X)H(X X X X X)I(X X X X)J(X X X X X
28、X X X)123456789 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27DaysAdding Resources to Gantt ChartsIDTask Name1A.Contract Signing2B.Questionnaire Design3C.Target Market ID4D.Survey Sample5E.Develop Presentation6F.Analyze results7G.Demographic analysis8H.Presentation to clientJohn SmithSue Bail
29、eyTom Jones,Steve CooperJohn SmithSandra HobbsIan TinningsJohn SmithJohn SmithMTWTFSSMTWTFSSMTWTFSSMTWTFSSMTWTFSSMTWTFSSMT17 Dec 0724 Dec 0731 Dec 0707 Jan 0814 Jan 0821 Jan 0828 Jan 08Critical Path calculationIDTask NameLeveling Delay1A0 edays2B0 edays3C0 edays4D0 edays5E0 edays6F0 edays7G0 edays8H
30、0 edays9I0 edays10J0 edays11K0 edays1 day3 days5 daysMTWTFSSMTWTFSSMTWTFSSMTWTFSSMTWTFSSMTWT17 Dec 0724 Dec 0731 Dec 0707 Jan 0814 Jan 0821 Jan 08CRASHING PROJECTS UNDER WHAT CONDITIONS?lThe initial schedule may be too optimistic.lMarket needs change and the project is in demand earlier than anticip
31、ated.lThe project has slipped considerably behind schedule.lThe contractual situation provides even more incentive to avoid schedule slippage.Options for Accelerating ActivitieslImproving the productivity of existing project resources(team meeting to focus efforts on the most important aspect of a t
32、ask.Review best practice how to do the task.)lChanging the working method employed for the activity,usually by altering the technology and types of resources employed(Change from drawing review to CAD model review)lIncreasing the quantity of project resources,including personnel,plant,and equipment(
33、OT,extra shifts,expedite freight,.)Caution with requesting(excessive)overtime!There is research that suggests that the greater the amount of overtime workers are expected to perform,the lower the marginal performance a company is likely to receive from them.For example,it was found that in engineeri
34、ng functions,optimal performance was realized after only four hours of overtime per week.By the time engineers were working 10 hrs of overtime,the marginal real extra output realized by the company had dropped to zero!Time-Cost Trade offs for Crashing ActivitiesCostActivity DurationNormalCrashedCras
35、hedNormalCrashPointNormalPointCostActivity DurationNormalCrashedCrashedNormalCrashPointNormalPointCRASHING ACTIVITIES AN CRASHING ACTIVITIES AN EXAMPLEEXAMPLEFormulaExample Calculating the Cost of CrashingSUPPOSE:NORMAL ACTIVITY DURATION=8 WEEKSNORMAL COST=$14,000CRASHED ACTIVITY DURATION=5 WEEKSCRA
36、SHED COST=$23,000THE ACTIVITY COST SLOPE =23,000 14,000 or,$9,000 =$3,000 per week 8 5 3timecrashtimenormaltnormaltcrashSlopecoscosProject cost changes when tasks along the critical path are being crashed.The cost goes up for every task being crashed.One can create a table listing all tasks,the norm
37、al duration and cost,and the crashed duration and cost.With this table it is possible to calculate the crashing cost per day for each task and select the task that makes the most financial sense to crash.Sample ProjectActivityCostCostA3 days1,000.00$2 days1,500.00$B4 days700.00$2 days1,000.00$C3 day
38、s2,500.00$2 days4,000.00$D6 days1,500.00$6 days1,500.00$E9 days3,750.00$7 days9,000.00$F4 days5,000.00$3 days7,000.00$G6 days2,550.00$5 days3,500.00$H8 days5,500.00$4 days7,550.00$Total:22,500.00$35,050.00$NormalCrashedDurationDurationCrashing showing crash cost/daySample ProjectActivityCostCostCras
39、hing Cost/dayA3 days1,000$2 days1,500$500$B4 days700$2 days1,000$150$C3 days2,500$2 days4,000$1,500$D6 days1,500$6 days1,500$N/AE9 days3,750$7 days9,000$2,625$F4 days5,000$3 days7,000$2,000$G6 days2,550$5 days3,500$950$H8 days5,500$4 days7,550$513$Total:22,500$35,050$NormalCrashedDurationDurationWit
40、h the cost information per crashed item,and a network diagram we can determine the tasks that actually have an effect on the overall project duration if crashed.Those tasks are on the critical path.Note that if a task gets crashed.The remaining network diagram has to be checked if there is now a new
41、 critical path!One can calculate the reduced project time and increased cost for each additional cost.The result will be an iterative process where one task after the other is being crashed.This information can be plotted very easily.Relationship between Cost and Time Saved in a Crashed Project$35,0
42、00.00$40,000.00$45,000.00$50,000.00$55,000.00$60,000.00$65,000.001920212223242526Duration(Weeks)Project CostAll normalCrash A+FCrash ACrash A+F+JAll CrashedIn order to make the best financial sense it is important to look at the whole picture.Usually the direct cost for a project go up,when it is be
43、ing crashed.However the e.g.the overhead cost or other fixed cost is going down.Also the project team has to keep potential penalties in mind,if the project exceeds a certain duration.This information is best shown in a graph like the following.0102030405060708090253035404550556065Duration(Weeks)Pro
44、ject Cost(Thousands)Direct costOverheadPenaltyTotalActivity-On-Arrow Networks1234ABC1 1 1234ABC2 2 23 3 34 4 4ABCTaskId numberEarliest event timeLatest event timePARTIAL AOA NETWORK ILLUSTRATING DUMMY ACTIVITIES 1ABC2341ABC234The dummy activities are used for Finish-Start Relationships when the star
45、t of one task depends on the completion of two other tasks,where one dependency does not lie in the network path of the activity.They do not have any work or time values assigned to them.Controversies in the use of NetworkslPERT/CPM is well understood and much employed,nevertheless networks are an a
46、bstract representation of events where time is reduced to a number.They may or may not be drawn to a scale that has a relationship to ongoing patterns or time.There are several caveat we need to keep in mind when we develop project activity networks:lNetworks can become too large and complex to be m
47、eaningfullFaulty reasoning in network construction can sometimes lead to oversimplification or incorrect representations.lNetworks are sometimes used for tasks which they are not well suitedlNetworks used to control the behavior of subcontractors have special dangers.lThere is a strong potential for
48、 positive bias in PERT estimations used in network construction.Monte Carlo Methodlhttp:/ above link gives a good review of Monte Carlo method.Monte Carlo Method is used in Project management for risk,cost,and time estimations.Generally it is most popular for risk calculations,but you will see it is very useful for time estimates as well.Milestones
