bab4b project schedulling

8/8/2019 BAB4B Project Schedulling

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Project SchedullingProject Schedulling


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Characteristics of a ProjectCharacteristics of a ProjectCharacteristics of a ProjectCharacteristics of a Project

* Memerlukan penyelesaian dari sejumlah aktivitas yg* Memerlukan penyelesaian dari sejumlah aktivitas yg

saling terkait (presaling terkait (pre--requested).requested).

Resources terbatas, spt waktu dan/atau biaya.Resources terbatas, spt waktu dan/atau biaya.

Biasanya memiliki struktur manajemen tersendiri.Biasanya memiliki struktur manajemen tersendiri.

Anggota tim berasal dari berbagai departemen danAnggota tim berasal dari berbagai departemen dan

bekerja secara temporer serta bertanggung jawab atasbekerja secara temporer serta bertanggung jawab atas

perencanaan (planning), penjadwalan (schedulling)perencanaan (planning), penjadwalan (schedulling)

dan pengendalian (controlling) project hingga selesai.dan pengendalian (controlling) project hingga selesai.


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Project TeamProject TeamProject TeamProject Team

ProjectProject

PlanPlan

ManagementManagement

InformationInformation

SystemSystem

ProjectProject

ScheduleSchedule

ProjectProjectManagerManager

ProjectProject

TeamTeam

Resources:Resources:

InternalInternal

Exec.Mgt.Exec.Mgt.

MarketingMarketing

EngineeringEngineeringProductionProduction

Qual.ControlQual.Control

Hum.Res.Hum.Res.

PurchasingPurchasing

ExternalExternal

SuppliersSuppliers

Subcontract.Subcontract.

UpdateUpdate

and Reviseand Revise

ScheduleSchedule

Update andUpdate and

Revise PlanRevise Plan


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Scheduling and Control ChartsScheduling and Control ChartsScheduling and Control ChartsScheduling and Control Charts

Horizontal Bar ChartsHorizontal Bar Charts

A version of the Gantt chartA version of the Gantt chart

Used to plan and schedule activitiesUsed to plan and schedule activities

As the project progresses, the status of activities isAs the project progresses, the status of activities isplotted on the chart, compared to the plan, and, ifplotted on the chart, compared to the plan, and, if

necessary, corrective action is takennecessary, corrective action is taken

more more


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Scheduling and Control ChartsScheduling and Control ChartsScheduling and Control ChartsScheduling and Control Charts

Horizontal Bar Charts (continued)Horizontal Bar Charts (continued)

AdvantagesAdvantages

Easy to understandEasy to understand

Easy to modify and updateEasy to modify and update Low costLow cost

DisadvantagesDisadvantages

Cumbersome for large projectCumbersome for large project

Must be keep up to dateMust be keep up to date Does not indicate the relationships among theDoes not indicate the relationships among the

activitiesactivities


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Horizontal Bar ChartHorizontal Bar ChartHorizontal Bar ChartHorizontal Bar Chart

a. Prelim. Propulsion Designa. Prelim. Propulsion Design

b. Prelim. Flight Sys. Designb. Prelim. Flight Sys. Design

c. Static Tests Ac. Static Tests Ad. Propulsion Design Modif.d. Propulsion Design Modif.

e. Static Tests Be. Static Tests B

f. Flight Tests Af. Flight Tests A

g. Flight Sys. Design Modif.g. Flight Sys. Design Modif.

h. Flight Tests Bh. Flight Tests Bi. Matl & Component Costsi. Matl & Component Costs

j. Labor & Overheads Costsj. Labor & Overheads Costs

Apr.Apr. MayMay JuneJune JulyJuly Aug.Aug.

aa

cc

dd

bb

ee ff

ggdd

dd

Project ActivitiesProject Activities


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Critical Path Method (CPM)Critical Path Method (CPM)Critical Path Method (CPM)Critical Path Method (CPM)

Designed to provide intense microDesigned to provide intense micro--controlcontrol

The system is dynamic; it continues to provideThe system is dynamic; it continues to provide

periodic reports as the project progressesperiodic reports as the project progresses


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Managers View ofCPMManagers View ofCPMManagers View ofCPMManagers View ofCPM

INPUTSINPUTS List of project activitiesList of project activities Precedence relationship among activitiesPrecedence relationship among activities Estimate of each activitys durationEstimate of each activitys duration

OUTPUTSOUTPUTS Estimated duration of projectEstimated duration of project Identification of critical activitiesIdentification of critical activities Amount of slack for each activityAmount of slack for each activity

CPM processing proceduresCPM processing procedures


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CPMCPM TerminologyTerminologyCPMCPM TerminologyTerminology

ActivityActivity

A task or a certain amount of work required in theA task or a certain amount of work required in theprojectproject

Requires time to completeRequires time to complete

Represented by an arrowRepresented by an arrow

Dummy ActivityDummy Activity

Indicates only precedence relationshipsIndicates only precedence relationships

Does not require any time of effortDoes not require any time of effort


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CPM TerminologyCPM TerminologyCPM TerminologyCPM Terminology

EventEvent

Signals the beginning or ending of an activitySignals the beginning or ending of an activity

Designates a point in timeDesignates a point in time

Represented by a circle (node)

Represented by a circle (node)

NetworkNetwork

Shows the sequential relationships amongShows the sequential relationships among

activities using nodes and arrowsactivities using nodes and arrows


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PathPath

A connected sequence of activities leading fromA connected sequence of activities leading fromthe starting event to the ending eventthe starting event to the ending event

CriticalP

athCriticalP

ath The longest path (time); determines the projectThe longest path (time); determines the project

durationduration

Critical ActivitiesCritical Activities

All of the activities that make up the critical pathAll of the activities that make up the critical path


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Earliest Start (ES)Earliest Start (ES)

The earliest that an activity can begin; assumes allThe earliest that an activity can begin; assumes all

preceding activities have been completedpreceding activities have been completed

Earliest Finish (EF)Earliest Finish (EF) ES + activity timeES + activity time

Latest Finish (LF)Latest Finish (LF)

The latest that an activity can finish and not changeThe latest that an activity can finish and not change

the project completion timethe project completion time

Latest Start (LS)Latest Start (LS)

LFLF -- activity timeactivity time


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CPM NetworkConventionsCPM NetworkConventionsCPM NetworkConventionsCPM NetworkConventions

11aa bbII

11aa

bb

cc

IIII

11

aa

bb

cc

IIIIII

ccaa11

ddbb

IVIV

cc

dd

aa

bb33

22

11

VV

22aa cc

11bb dd

VIVI


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Steps in CPM AnalysisSteps in CPM AnalysisSteps in CPM AnalysisSteps in CPM Analysis

Draw the CPM networkDraw the CPM network

A graphic view of the relationships among theA graphic view of the relationships among the

required activitiesrequired activities

Analyze the paths through the networkAnalyze the paths through the network Determine the length of each path (the timeDetermine the length of each path (the time

required to complete each path)required to complete each path)

Starting at the beginning of the network andStarting at the beginning of the network and

working toward the end (from left to right),working toward the end (from left to right),determine the ES and the EF for each activitydetermine the ES and the EF for each activity

. . . more. . . more


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Path analysis (continued)Path analysis (continued)

Identify the critical path(s) (the longest path[s]Identify the critical path(s) (the longest path[s]

through the network)through the network)

The critical path(s) determines how long theThe critical path(s) determines how long theproject will takeproject will take

. . . more. . . more


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Determine the slack for each activityDetermine the slack for each activity

Working from the end of the project networkWorking from the end of the project network

(from right to left), find the LF and the LS for each(from right to left), find the LF and the LS for each

activityactivity Compute the activitys slackCompute the activitys slack

slack = LSslack = LS -- ES = LFES = LF -- EFEF

Slack is the maximum amount of time that thisSlack is the maximum amount of time that this

activity can be delay in its completion before itactivity can be delay in its completion before itbecomes a critical activity, i.e., delays completionbecomes a critical activity, i.e., delays completion

of the projectof the project


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CPM ExampleCPM ExampleCPM ExampleCPM Example

TaskTask PredecessorPredecessor Time, hTime, h

aa -- 66

bb -- 88

cc -- 55

dd bb 1313

ee cc 99

ff aa 1515

gg aa 1717

hh ff 99

ii gg 66

jj d, ed, e 1212


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CPM NetworkCPM Network

a, 6a, 6

f, 15f, 15

b, 8b, 8

c, 5c, 5e, 9e, 9

d, 13d, 13

g, 17g, 17 h, 9h, 9

i, 6i, 6

j, 12j, 12


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Paths EnumeratedPaths Enumerated

PathPath Length of PathLength ofPath

aa--ff--hh 6 + 15 + 9 = 306 + 15 + 9 = 30

aa--gg--II 6 + 17 + 6 = 296 + 17 + 6 = 29

bb--dd--jj 8 + 13 + 12 = 33*8 + 13 + 12 = 33*

cc--ee--jj 5 + 9 + 12 = 265 + 9 + 12 = 26

* Critical path* Critical path


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ES and EF TimesES and EF Times

a, 6a, 6a, 6a, 6

f, 15f, 15f, 15f, 15

b, 8b, 8b, 8b, 8

c, 5c, 5c, 5c, 5

e, 9e, 9e, 9e, 9

d, 13d, 13d, 13d, 13

g, 17g, 17g, 17g, 17 h, 9h, 9h, 9h, 9

i, 6i, 6i, 6i, 6

j, 12j, 12j, 12j, 12

0 6

0 8

0 5


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a, 6a, 6a, 6a, 6

f, 15f, 15f, 15f, 15

b, 8b, 8b, 8b, 8

c, 5c, 5c, 5c, 5

e, 9e, 9e, 9e, 9

d, 13d, 13d, 13d, 13

g, 17g, 17g, 17g, 17 h, 9h, 9h, 9h, 9

i, 6i, 6i, 6i, 6

j, 12j, 12j, 12j, 12

0 6

0 8

0 5

5 14

8 21

6 23

6 21


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a, 6a, 6a, 6a, 6

f, 15f, 15f, 15f, 15

b, 8b, 8b, 8b, 8

c, 5c, 5c, 5c, 5

e, 9e, 9e, 9e, 9

d, 13d, 13d, 13d, 13

g, 17g, 17g, 17g, 17 h, 9h, 9h, 9h, 9

i, 6i, 6i, 6i, 6

j, 12j, 12j, 12j, 12

0 6

0 8

0 5

5 14

8 21 21 33

6 2321 30

23 29

6 21

Projects EF = 33Projects EF = 33


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LS and LF TimesLS and LF Times

a, 6a, 6a, 6a, 6

f, 15f, 15f, 15f, 15

b, 8b, 8b, 8b, 8

c, 5c, 5c, 5c, 5

e, 9e, 9e, 9e, 9

d, 13d, 13d, 13d, 13

g, 17g, 17g, 17g, 17

h, 9h, 9h, 9h, 9

i, 6i, 6i, 6i, 6

j, 12j, 12j, 12j, 12

0 6

0 8

0 5

5 14

8 2121 33

6 23

21 30

23 29

6 21

21 33

27 33

24 33


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LS and LF TimesLS and LF Times

a, 6a, 6a, 6a, 6

f, 15f, 15f, 15f, 15

b, 8b, 8b, 8b, 8

c, 5c, 5c, 5c, 5

e, 9e, 9e, 9e, 9

d, 13d, 13d, 13d, 13

g, 17g, 17g, 17g, 17

h, 9h, 9h, 9h, 9

i, 6i, 6i, 6i, 6

j, 12j, 12j, 12j, 12

0 6

0 8

0 5

5 14

8 2121 33

6 23

21 30

23 29

6 21

4 10

0 8

7 12

12 21

21 33

27 33

8 21

10 27

24 33

18 24


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Critical PathCritical Path

a, 6a, 6a, 6a, 6

f, 15f, 15f, 15f, 15

b, 8b, 8b, 8b, 8

c, 5c, 5c, 5c, 5

e, 9e, 9e, 9e, 9

d, 13d, 13d, 13d, 13

g, 17g, 17g, 17g, 17 h, 9h, 9h, 9h, 9

i, 6i, 6i, 6i, 6

j, 12j, 12j, 12j, 12


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Program EvaluationProgram Evaluation

and Review Technique (PERT)and Review Technique (PERT)

Program EvaluationProgram Evaluation

and Review Technique (PERT)and Review Technique (PERT)

The technique is based on the assumption that anThe technique is based on the assumption that anactivitys duration follows a probability distributionactivitys duration follows a probability distribution

instead of being a single value.instead of being a single value.

The probabilistic information about the activities isThe probabilistic information about the activities is

translated into probabilistic information about thetranslated into probabilistic information about the

project.project.


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PERTPERTPERTPERT

Three time estimates are required to compute theThree time estimates are required to compute theparameters of an activitys duration distribution:parameters of an activitys duration distribution:

pessimistic timepessimistic time (t(tpp )) -- the time the activity wouldthe time the activity would

take if things did not go welltake if things did not go well

most likely timemost likely time (t(tmm )) -- the consensus best estimatethe consensus best estimate

of the activitys durationof the activitys duration

optimistic timeoptimistic time (t(too )) -- the time the activity wouldthe time the activity would

take if things did go welltake if things did go well . . . more. . . more


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From these three time estimates about an activity, twoFrom these three time estimates about an activity, twoprobability distribution parameters are calculated: theprobability distribution parameters are calculated: the

mean (tmean (tee ) and the variance (V) and the variance (Vtt ).).

ttee = ( t= ( too + 4t+ 4tmm + t+ tpp ) / 6) / 6

VVtt = [ ( t= [ ( tpp -- ttoo ) / 6 ]) / 6 ]22

PERTPERTPERTPERT


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Steps in PERT AnalysisSteps in PERT AnalysisSteps in PERT AnalysisSteps in PERT Analysis

Draw the network.Draw the network.

Analyze the paths through the network and find the criticalAnalyze the paths through the network and find the critical

path.path.

The length of the critical path is the mean of the projectThe length of the critical path is the mean of the project

duration probability distribution which is assumed to beduration probability distribution which is assumed to benormal.normal.

The standard deviation of the project duration probabilityThe standard deviation of the project duration probability

distribution is computed by adding the variances of the criticaldistribution is computed by adding the variances of the critical

activities (all of the activities that make up the critical path)activities (all of the activities that make up the critical path)and taking the square root of that sumand taking the square root of that sum

Probability computations can now be made using the normalProbability computations can now be made using the normal

distribution table.distribution table.


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PERT ExamplePERT Example

Immed. Optimistic Most Likely PessimisticImmed. Optimistic Most Likely PessimisticActivityActivity Predec.Predec. Time (Hr.Time (Hr.)) Time (Hr.)Time (Hr.) Time (Hr.)Time (Hr.)

AA ---- 4 6 84 6 8

BB ---- 1 4.5 51 4.5 5

C A 3 3 3C A 3 3 3D A 4 5 6D A 4 5 6

E AE A 0.5 1 1.50.5 1 1.5

F B,C 3 4 5F B,C 3 4 5

G B,C 1 1.5 5G B,C 1 1.5 5

H E,F 5 6 7H E,F 5 6 7I E,F 2 5 8I E,F 2 5 8

J D,H 2.5 2.75 4.5J D,H 2.5 2.75 4.5

K G,I 3 5 7K G,I 3 5 7


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PERT NetworkPERT Network

AA

DD

CC

BB

FF

EE

GG

II

HH

KK

JJ


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Activity Expected Time and VarianceActivity Expected Time and VarianceActivityActivity Expected TimeExpected Time VarianceVariance

AA 66 4/94/9

BB 44 4/94/9

CC 33 00DD 55 1/91/9

EE 11 1/361/36

FF 44 1/91/9

GG 22 4/94/9

HH 66 1/91/9

II 55 11

JJ 33 1/91/9

KK 55 4/94/9


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Earliest/Latest TimesEarliest/Latest Times

ActivityActivity ESES EFEF LSLS LFLF Slack Slack

A 0A 0 66 00 66 0 *critical0 *critical

B 0B 0 44 55 99 55

C 6C 6 99 66 99 0 *0 *D 6D 6 1111 1515 2020 99

E 6E 6 77 1212 1313 66

F 9F 9 1313 99 1313 0 *0 *

G 9G 9 1111 1616 1818 77HH 1313 1919 1414 2020 11

II 1313 1818 1313 1818 0 *0 *

JJ 1919 2222 2020 2323 11

KK 1818 2323 1818 2323 0 *0 *


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Probability the project will be completed within 24

Probability the project will be completed within 24

hourshours

VVpathpath = V= VAA + V+ VCC + V+ VFF + V+ VII + V+ VKK

= 4/9 + 0 + 1/9 + 1 + 4/9= 4/9 + 0 + 1/9 + 1 + 4/9

= 2= 2

WWpathpath = 1.414= 1.414

zz = (24= (24 -- 23)/23)/W!W!(24(24--23)/1.414 = .7123)/1.414 = .71


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Standard Normal DistributionStandard Normal DistributionStandard Normal DistributionStandard Normal Distribution


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PERT ExamplePERT ExamplePERT ExamplePERT Example

Probability the project will be completed within 24Probability the project will be completed within 24hourshours

From the Standard Normal Distribution table:From the Standard Normal Distribution table:

P(zP(z


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End of Project SchedullingEnd of Project Schedulling

bab4b project schedulling

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