NETWORK, CPM DAN PERT

Dr. Mohammad Abdul Mukhyi, SE., MM

1

PENDAHULUAN

Hal penting dalam manajemen proyek adalah :Ketepatan memilih bentuk organisasi (tim)Ketepatan memilih bentuk organisasi (tim)Memilih manajer proyek yang tepatAktifit i t i d k di i b ikAktifitas integrasi dan koordinasi yang baik

Diluar hal tsb diperlukan :Apa yang akan dikerjakanBagaimana pengendaliannya?

2

LINGKUP PEKERJAAN

Perencanaan dan pengendalian :S b l k di l iSebelum proyek dimulaiSelama proyek berlangsungKoreksi pada saat terjadi perbedaan antararencana dan

l kpelaksanaanDitujukan untuk mengurangi ketidakpastian tentang

g k dih ilk d i g j kapa yang akan dihasilkan dari pengerjaan proyek

3

ALAT ALAT PERENCANAAN

Banyak metoda yang digunakan dalam perencanaanantara lain:

Work breakdown structure (WBS) untukmenentukan pekerjaan pekerjaan yang ada dalamproyekproyek.Matriks tanggungjawab untuk menentukanorganisasi proyek, orang orang kunci dantanggungjawabnyatanggungjawabnya.Gantt charts digunakan untuk menunjukkan jadwalinduk proyek, dan jadwal pekerjaan secara detail.Jaringan kerja (network) untuk memperlihatkanurutan pekerjaan, kapan dimuiai, kapan selesai, kapan proyek secara keseluruhan selesai.p p y

4

PENDEFINISIAN PEKERJAANUtk proyek dalam skala besar diperlukan metode untukmenentukan elemen‐elemen proyek dalam bagian yang lebih detail.lebih detail.Dapat diketahui keterkaian antar aktifitas, urutan waktudan personilnya.Work Breakdown Structure (WBS)Work Breakdown Structure (WBS)

Manfaat dari WBS :Dalam tahap analisis WBS dapat digunakan untuk memastikan akurasi dan kelengkapan dari semua personil proyekDijadikan sebagai dasar penganggaran dan penjadwalanSebagai alat kontrol pelaksanaan proyek

5

PROYEK

Suatu proyek adalah suatu usaha temporer yang menyertakan suatu urutan aktivitas yang menyertakan suatu urutan aktivitas yang dihubungkan dengan sumber daya, yang dirancanguntuk mencapai suatu hasil yang unik dan spesifikuntuk mencapai suatu hasil yang unik dan spesifikdan yang beroperasi di dalam waktu, biaya danbatasan mutu dan sering digunakan untukmemperkenalkan perubahan.

6

CHARACTERISTIC OF A PROJECT

A unique, one-time operational activity or effortRequires the completion of a large number of interrelated activitiesEstablished to achieve specific objectiveResources such as time and/or money are Resources, such as time and/or money, are limitedT i ll h it g t t tTypically has its own management structureNeed leadership

7

APA PROYEK MANAJEMEN?

Aplikasi dari suatu koleksi teknik dan perkakasuntuk mengarahkan penggunaan sumber daya

b b d k h h d iyang berbeda ke arah pemenuhan dari suatuyang unik, kompleks, waktu, biaya dan batasanmutu.Perang dunia II, manakala otoritas militer menggunakan teknik operasional research

t k k j l h k i untuk merencanakan jumlah maksimum penggunaan sumber daya.Salah satu teknik ini adalah penggunaanSalah satu teknik ini adalah penggunaanjaringan untuk menghadirkan suatu sistem dariaktivitas terkait

8

PROJECT MANAGEMENT PROCESSProject planningProject scheduling Project controlProject teamProject team

made up of individuals from various areas and departments within a company

Matrix organizationa team structure with members from functional areas, depending

kill i dp g

on skills requiredProject Manager

most important member of project teamScope statement

a document that provides an understanding, justification, and expected result of a project

Statement of workwritten description of objectives of a projectp j p j

Organizational Breakdown Structurea chart that shows which organizational units are responsible for work items

Responsibility Assignment MatrixResponsibility Assignment Matrixshows who is responsible for work in a project

9

Work Breakdown Structure for Computer Order Processing System Project

Work Breakdown Structure for Computer Order Processing System ProjectProcessing System ProjectProcessing System Project

10

PROJECT PLANNING

Resource Availability and/or LimitsDue date late penalties early completion Due date, late penalties, early completion incentivesBudgetBudget

Activity InformationId if ll i d i i iIdentify all required activitiesEstimate the resources required (time) to

l t h ti itcomplete each activityImmediate predecessor(s) to each activity needed to create interrelationshipsneeded to create interrelationships

11

PROJECT SCHEDULING AND CONTROL TECHNIQUES

Gantt Chart

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

Program Evaluation and Review Technique (PERT)

12

Gantt Chart

Graph or bar chart with a bar for each project activity that shows passage of time

Provides visual display of project scheduleProvides visual display of project schedule

13

NETWORKNETWORK

Untuk perencanaan.pHubungan antara komponen dalam network danelemen dalam masalah riil

-Penerapan model network:Masalah transportasiMasalah prosesingP d d li kPerencanaan dan pengendalian proyekpenugasan

14

Masalah Transportasi:Masalah Transportasi:

PABRIK

A A AA1 A2 A3= suplly

TEMPAT PEMASARAN B3B2B1

= demand

15

BIAYA TRANSPORTASI DAN DISTRIBUSI BARANG

Tempatpemasaran

pabrik1 2 3 ……. M

Jumlahpersediaan

1C

11X

11

C12

X12

C13

X13

…….C

1MX

1M

S1

2C

21X

21

C22

X22

C23

X23

…….C

2MX

2M

S2

::3

::

::

::

…….::

::

NC

N1X

N1

CN2

XN2

CN3

XN3

…….C

NMX

NM

SN

Jumlah D

16

Jumlahpermintaan

D1

D2

D3

…….D

M ΣDJ≤ Σ S

J

Formulasi model transportasi

321idiDXSk

XC :Min

m

n

1 iij

m

1 jij

≤∑

∑∑= = XC :Min

n

1 iij

m

1 jij∑∑

= =

n ..., 3 2, 1, j dimana S X

m...,32,1,idimana D X Sk.

j

m

ij

i1 j

ij

=≥

=≤

∑

∑=

n321jdimanaSX

m ..., 3 2, 1, i dimana D X Sk.

m

i

m

1 jij ==

∑

∑=

jdan i dimana 0 X ij

1 j

≥=

jdan i dimana 0 X

n...,32,1,jdimana SX

ij

j1 j

ij

≥

==∑=

17

Masalah TranshipmentMasalah Transhipment

Untuk menentukan jumlah dan lokasi titik angkutanj gserta berguna untuk menentukan jumlah dan lokasititik angkutan secara optimal dengan meminimalkanbiaya angkutan antar lokasi.

18

+ 1 truk

3

C23 C34

C36

6421 7

+ 8 truk

C12

0 truk 3 truk 4 truk

C24

C

C46 C67

5

+ 8 truk 0 truk - 3 truk - 4 truk

C25

C54

C56

0 truk

19

LokasiRute Pengiriman Kapasi

tasBarangX12 X23 X24 X25 X34 X36 X54 X56 X63 X67

1 +1 0 0 0 0 0 0 0 0 0 +8

2 -1 +1 +1 +1 0 0 0 0 0 0 0

3 0 -1 0 0 +1 +1 0 0 -1 0 +1

4 0 0 -1 0 -1 0 -1 0 0 0 -2

5 0 0 0 -1 0 0 +1 +1 0 0 0

6 0 0 0 0 0 -1 0-1

+1 +1 -3

7 0 0 0 0 0 0 0 0 0 1 4

20

7 0 0 0 0 0 0 0 0 0 -1 -4

Fungsi Linear Programing

8 X : XCXCXCXCXCXCXCXCXCXC :Min

12

6767565654544646363634342525242423231212

=+++++++++

sk

0XXX2- X-XX-X-

1 XX X- 0- XXXX-

54463424

363423

25242312

++=+=++=+++

jdanisemuauntuk0X4 X - 3- XX-X-X- 0 XXX-

67

67564636

565425

≥−=

=+=++

jdan i semuauntuk 0 Xij ≥

21

HISTORY OF CPM/PERT

Critical Path Method (CPM)E I Du Pont de Nemours & Co. (1957) for construction of new h i l l d i h dchemical plant and maintenance shut-down

Deterministic task timesActivity on node network constructionActivity-on-node network constructionRepetitive nature of jobs

Project Evaluation and Review Technique (PERT)Project Evaluation and Review Technique (PERT)U S Navy (1958) for the POLARIS missile programMultiple task time estimates (probabilistic nature)p (p )Activity-on-arrow network constructionNon-repetitive jobs (R & D work)

22

TEKNIK CPMTEKNIK CPM

Pekerjaan-pekerjaan dalam proyek harus menandaij p j p ysaat berakhirnya proyek.Pekerjaan-pekerjaan dapat dimulai, diakhiri danj p j pdilaksanakan secara terpisah dalam suatu rangkaiantertentu.Pekerjaan-pekerjaan dapat diatur menurut suaturangkaian tertentu.

23

ATURAN

Setiap aktivitas ditujukan dengan suatu cabang tertentu, cabang inimenunjukkan saat dimulainya dan diakhirinya suatu kejadian.Antara suatu cabang dengan cabang lainnya hanya menunjukkanhubungan antar aktivitas atau pekerjaan yang berbeda.Bila sejumlah aktivitas berakhir pada suatu kejadian, maka inia seju a a t tas be a pada suatu ejad a , a aberarti bahwa kejadian ini tidak dapat dimulai sebelum aktivitasyang berakhir pada kejadian ini selesai.Aktivitas dummy digunakan untuk menggabungkan dua buahAktivitas dummy digunakan untuk menggabungkan dua buahkejadian, bila antara suatu kejadian dan kejadian yang mendahuluinya tidak dihubungkan dengan suatu aktivitas tertentu. Aktivitas dummy ini tidak mempunyai biaya dan waktuAktivitas dummy ini tidak mempunyai biaya dan waktu.Setiap kejadian diberikan tanda angka, sedang setiap aktivitasdiberikan tanda angka menurut kejadian awal dan kejadian yang mengakhiri.

24

PROJECT NETWORK

• Network analysis is the general name given to certain specific techniques which can be used for the planning, management and control of projects

Use of nodes and arrowsArrows An arrow leads from tail to head directionally

Indicate ACTIVITY, a time consuming effort that is required to perform a part of the workpart of the work.

Nodes n A node is represented by a circle- Indicate EVENT, a point in time where one or more activities start and/or

finish.

• Activity– A task or a certain amount of work required in the project– Requires time to complete– Represented by an arrow

• Dummy Activity

25

y y– Indicates only precedence relationships– Does not require any time of effort

EventProject Network

EventSignals the beginning or ending of an activityDesignates a point in timeR t d b i l ( d )Represented by a circle (node)

NetworkShows the sequential relationships among activities using nodes and arrows

A i i d (AON)Activity-on-node (AON)

nodes represent activities, and arrows show precedence relationshipsrelationships

Activity-on-arrow (AOA)

arrows represent activities and nodes are events for points

26

arrows represent activities and nodes are events for points in time

AOA PROJECT NETWORK FOR HOUSE

3

32 0

11 2 4 6 7

3Lay foundation Dummy

Finish work

Build house

31 1

11 2 4 6 7

5

Design house and obtain financing

Order and receive materials

Select carpet

Select paint

AON Project Network for House

22

43

7

Lay foundations Build house

Finish work

13

3 6

71Start

Design house and

27

31 5

11obtain financing

Order and receive materials

Select paintSelect carpet

SITUATIONS IN NETWORK DIAGRAM

AB

A

C

A must finish before either B or C can start

AA

B

C both A and B must finish before C can start

CA

both A and C must finish before either of B or D can start

DB

start

AAB

Dummy

A must finish before B can start

both A and C must finish before D can start

28

CD

CONCURRENT ACTIVITIES

ff 3

2 3

Lay foundationLay foundation 3DummyDummyLay Lay

foundationfoundation22 00

Order materialOrder material 42Order materialOrder material

11

(a)(a) Incorrect precedence Incorrect precedence relationshiprelationship

(b)(b) Correct precedence Correct precedence relationshiprelationship

29

NETWORK EXAMPLEIll t ti f t k l i f i d ig f d t d it i t d Illustration of network analysis of a minor redesign of a product and its associated packaging.

The key question is: How long will it take to complete this project ?The key question is: How long will it take to complete this project ?

30

For clarity, this list is kept to a minimum by specifying only immediate relationships, that is relationships involving activities that "occur near to each other in time".

31

QUESTIONS TO PREPARE ACTIVITY NETWORKIs this a Start Activity? I thi Fi i h A ti it ? Is this a Finish Activity? What Activity Precedes this? What Activity Follows this? What Activity Follows this? What Activity is Concurrent with this?

32

CPM CALCULATION

PathA connected sequence of activities leading from q gthe starting event to the ending event

Critical PathCritical PathThe longest path (time); determines the project duration

Critical ActivitiesAll of the activities that make up the critical pathAll of the activities that make up the critical path

33

FORWARD PASSEarliest Start Time (ES)Earliest Start Time (ES)

earliest time an activity can start ES = maximum EF of immediate predecessors

Earliest finish time (EF)Earliest finish time (EF)earliest time an activity can finishearliest start time plus activity time

EF= ES + tEF= ES + t

Latest Start Time (LS)Backward Pass

Latest time an activity can start without delaying critical path time

LS= LF - tLatest finish time (LF)Latest finish time (LF)

latest time an activity can be completed without delaying critical path time

LS = minimum LS of immediate predecessors

34

CPM ANALYSIS

Draw the CPM networkAnalyze the paths through the networkDetermine the float for each activityDetermine the float for each activity

Compute the activity’s floatfloat = LS - ES = LF - EFfloat LS ES LF EF

Float is the maximum amount of time that this activity can be delay in its completion before it becomes a critical activity, i.e., delays completion of the project

Find the critical path is that the sequence of activities and events where there is no “slack” i e Zero slackevents where there is no slack i.e.. Zero slack

Longest path through a networkFind the project duration is minimum project completion timep j p j p

35

CPM EXAMPLE: CPM Network

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

a, 6a, 6a, 6a, 6g, 17g, 17g, 17g, 17 h, 9h, 9h, 9h, 9

ii 66ii 66

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

ii, 6, 6ii, 6, 6

d, 13d, 13d, 13d, 13 j, 12j, 12j, 12j, 12

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

36

CPM EXAMPLEES and EF Times f, 15f, 15f, 15f, 15

a, 6a, 6a, 6a, 6 g, 17g, 17g, 17g, 17 h, 9h, 9h, 9h, 9

ii 66ii 660 6

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

ii, 6, 6ii, 6, 60 6

d, 13d, 13d, 13d, 13 jj, 12, 12jj, 12, 120 8

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

e, 9e, 9e, 9e, 90 5

37

CPM EXAMPLE

ES and EF Times f, 15f, 15f, 15f, 15

6 21

a, 6a, 6a, 6a, 6 g, 17g, 17g, 17g, 17 h, 9h, 9h, 9h, 9

ii 66ii 660 6 6 23

6 21

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

ii, 6, 6ii, 6, 60 6 6 23

d, 13d, 13d, 13d, 13 j, 12j, 12j, 12j, 120 8

8 21c, 5c, 5c, 5c, 5

e, 9e, 9e, 9e, 90 5

8 21

38

5 14

CPM EXAMPLE

ES and EF Times ff, 15, 15ff, 15, 15

6 21

a, 6a, 6a, 6a, 6 g, 17g, 17g, 17g, 17 h, 9h, 9h, 9h, 9

ii 66ii 660 6 6 2321 30

6 21

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

ii, 6, 6ii, 6, 60 6 6 23

23 29

d, 13d, 13d, 13d, 13 j, 12j, 12j, 12j, 120 8

8 21 21 33c, 5c, 5c, 5c, 5

e, 9e, 9e, 9e, 90 5

8 21

Project’s EF = 33Project’s EF = 33

39

5 14

CPM EXAMPLE

LS and LF Times f, 15f, 15f, 15f, 15

h 9h 9h 9h 96 21

a, 6a, 6a, 6a, 6 g, 17g, 17g, 17g, 17

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

ii 66ii 660 6 6 23

21 30

24 33

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

ii, 6, 6ii, 6, 60 6 6 23

23 29

27 33d, 13d, 13d, 13d, 13 jj, 12, 12jj, 12, 120 8

8 21 21 33

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

e, 9e, 9e, 9e, 90 5

21 33

40

5 14

CPM EXAMPLECPM EXAMPLE

LS and LF Times f, 15f, 15f, 15f, 15

h 9h 9h 9h 96 21

a, 6a, 6a, 6a, 6 g, 17g, 17g, 17g, 17

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

ii 66ii 660 6 6 23

21 30

24 33

18 24

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

ii, 6, 6ii, 6, 60 6 6 23

23 294 10

27 33

10 27

d, 13d, 13d, 13d, 13 j, 12j, 12j, 12j, 120 8

8 21 21 33

0 8

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

e, 9e, 9e, 9e, 90 5

7 12

21 338 21

41

5 14 7 12

12 21

CPM EXAMPLECPM EXAMPLEFl tFloat

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

h 9h 9h 9h 96 21 3

a, 6a, 6a, 6a, 6 g, 17g, 17g, 17g, 17

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

ii 66ii 660 6 6 23

21 30

24 33

9 24 3

3

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

ii, 6, 6ii, 6, 60 6 6 23

23 293 9

27 33

10 27 3 4

4

d, 13d, 13d, 13d, 13 j, 12j, 12j, 12j, 120 8

8 21 21 330 80

0

0 c, 5c, 5c, 5c, 5

e, 9e, 9e, 9e, 90 5

5 147 12

21 338 21 0

7

42

5 14 7 12

12 21 7

CPM EXAMPLE

Critical Path f, 15f, 15f, 15f, 15

a, 6a, 6a, 6a, 6 g, 17g, 17g, 17g, 17 h, 9h, 9h, 9h, 9

ii 66ii 66

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

ii, 6, 6ii, 6, 6

d, 13d, 13d, 13d, 13j, 12j, 12j, 12j, 12

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

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

43

EXAMPLE

Illustration of network analysis of a minor redesign of a product and its associated packaging.

The key question is: How long will it take to complete this project ?

44

For clarity, this list is kept to a minimum by specifying only immediate relationships, that is relationships involving activities that "occur near to each other in time".

45

Before starting any of the above activity, the questions asked would be

•"What activities must be finished before this activity can start"

as ed would be

•could we complete this project in 30 weeks?

could we complete this project in 2 weeks?•could we complete this project in 2 weeks?

One answer could be, if we first do activity 1, then activity 2, then activity 3, ...., then activity 10, then activity 11 and the project would then take the sum of the activity completion times, 30 weeks.

“What is the minimum possible time in which we can complete this project ? “

46

We shall see below how the network analysis diagram/picture we construct helps us to answer this question.

47

CRITICAL PATH TAKES 24 WEEKS FOR THE COMPLETION OF THE PROJECT

48

Packages are available to determine the shortest path and other relevant information.

49

Data entry window

50

Output of the package

51

PERT PERT is based on the assumption that an activity’s duration PERT is based on the assumption that an activity s duration follows a probability distribution instead of being a single valueThree time estimates are required to compute the q pparameters of an activity’s duration distribution:

pessimistic time (tp ) - the time the activity would take if things did not go wellg gmost likely time (tm ) - the consensus best estimate of the activity’s durationoptimistic time (to ) - the time the activity would take if optimistic time (to ) the time the activity would take if things did go well

M ( t d ti ) t tp + 4 tm + toMean (expected time): te = tp 4 tm to6

t t2

52

Variance: Vt =σ 2 = tp - to6

PERT ANALYSISDraw the network.Analyze the paths through the network and find the critical path.The length of the critical path is the mean of the project duration probability distribution which is assumed to be normalduration probability distribution which is assumed to be normalThe standard deviation of the project duration probability distribution is computed by adding the variances of the critical activities (all of the activities that make up the critical path) and taking the square root of that sumProbability computations can now be made using the normal Probability computations can now be made using the normal distribution table.

53

PROBABILITY COMPUTATION

Determine probability that project is completed within specified time

Z = x - µ

σ

where µ = tp = project mean time

σ = project standard mean time

x = (proposed ) specified time

54

NORMAL DISTRIBUTION OF PROJECT TIMENORMAL DISTRIBUTION OF PROJECT TIME

Probability

Zσ

µ = tp Timex

55

PERT EXAMPLE

Immed. Optimistic Most Likely PessimisticActivity Predec. Time (Hr.) Time (Hr.) Time (Hr.)Activity Predec. Time (Hr.) Time (Hr.) Time (Hr.)

A -- 4 6 8B -- 1 4.5 5C A 3 3 3D A 4 5 6 E A 0 5 1 1 5E A 0.5 1 1.5F B,C 3 4 5G B,C 1 1.5 5H E F 5 6 7H E,F 5 6 7I E,F 2 5 8J D,H 2.5 2.75 4.5J D,H 2.5 2.75 4.5K G,I 3 5 7

56

PERT EXAMPLE

PERT Network

DD

AA EE HH JJ

CC

BB II KKFF

GG

KK

57

PERT EXAMPLE

Activity Expected Time VarianceA 6 4/9A 6 4/9B 4 4/9C 3 0C 3 0D 5 1/9E 1 1/36F 4 1/9G 2 4/9H 6 1/9H 6 1/9I 5 1J 3 1/9J 3 1/9K 5 4/9

58

PERT EXAMPLE

Activity ES EF LS LF SlackA 0 6 0 6 0 *criticalA 0 6 0 6 0 *criticalB 0 4 5 9 5C 6 9 6 9 0 *D 6 11 15 20 9E 6 7 12 13 6F 9 13 9 13 0 *F 9 13 9 13 0 G 9 11 16 18 7H 13 19 14 20 1I 13 18 13 18 0 *I 13 18 13 18 0 *J 19 22 20 23 1K 18 23 18 23 0 *

59

PERT EXAMPLE

Vpath = VA + VC + VF + VI + VK

= 4/9 + 0 + 1/9 + 1 + 4/9 = 2

σpath = 1.414z = (24 23)/σ (24 23)/1 414 = 71z = (24 - 23)/σ = (24-23)/1.414 = .71

From the Standard Normal Distribution table: P(z < .71) = .5 + .2612 = .7612

60

PROJECT COST

61

COST CONSIDERATION IN PROJECT

Project managers may have the option or requirement to crash the project, or accelerate the completion of the project.This is accomplished by reducing the length of the critical path(s).The length of the critical path is reduced by reducing the duration of the activities on the critical path.If each activity requires the expenditure of an amount of money to y q p yreduce its duration by one unit of time, then the project manager selects the least cost critical activity, reduces it by one time unit, and traces that change through the remainder of the network.As a result of a reduction in an activity’s time, a new critical path may be created.When there is more than one critical path, each of the critical paths p pmust be reduced.If the length of the project needs to be reduced further, the process is repeated.

62

PROJECT CRASHINGCrashing

reducing project time by expending additional resourcesresources

Crash timean amount of time an activity is reducedy

Crash costcost of reducing activity time

G lGoalreduce project duration at minimum cost

63

ACTIVITY CRASHING

Crashing activityCrash cost

Slope = crash cost per unit time

Normal ActivityNormal cost

Normal time

64

Activity timeCrash time

TIME-COST RELATIONSHIP

Crashing costs increase as project duration decreasesIndirect costs increase as project duration increasesReduce project length as long as crashing costs are less than indirect costsReduce project length as long as crashing costs are less than indirect costs

Time-Cost Tradeoff Total project costMin total cost =

Indirect cost

Total project costoptimal project time

Direct cost

65

time

PROJECT CRASHING EXAMPLE

44

11

2288

441212

774411

1212

33 66

44

44 5544

44

66

TIME COST DATA

Activity Normal ti

Normal t R

Crash ti

Crash t R

Allowable h ti

slopetime cost Rs time cost Rs crash time

12

128

30002000

75

50003500

53

4005002

34

8412

2000400050000

539

3500700071000

313

50030007000

56

44

500500

11

11001100

33

200200

7 4 1500 3 22000 1 700075000 110700

67

28

R500 R7000

R70012

4Project duration = 36

112

874

R70012

From…..

34 5

4

64

R400

R3000 R200R3000 R200

2R500 R7000

4

To…..17

28

74

R70012

7

34 5

4

64

R400

R200

Project

duration = 314

R3000 R200R200Additional cost =

R2000

68

BENEFITS OF CPM/PERT

Useful at many stages of project managementMathematically simpleGive critical path and slack timeGive critical path and slack timeProvide project documentationUseful in monitoring costs

CPM/PERT can answer the following important questions:

•How long will the entire project take to be completed? What are the risks involved? •Which are the critical activities or tasks in the project which could delay the entire

questions:

Which are the critical activities or tasks in the project which could delay the entire project if they were not completed on time?

•Is the project on schedule, behind schedule or ahead of schedule? •If the project has to be finished earlier than planned, what is the best way to do this at

?

69

the least cost?

LIMITATIONS TO CPM/PERTClearly defined, independent and stable activitiesSpecified precedence relationshipsOver emphasis on critical pathsDeterministic CPM modelDeterministic CPM modelActivity time estimates are subjective and depend on judgmentPERT assumes a beta distribution for these time estimates, but the actual distribution may be differentPERT consistently underestimates the expected project y p p jcompletion time due to alternate paths becoming critical

To overcome the limitation, Monte Carlo simulations can be performed on the network to eliminate the optimistic bias

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COMPUTER SOFTWARE FOR PROJECT MANAGEMENTFOR PROJECT MANAGEMENT

Microsoft Project (Microsoft Corp.)MacProject (Claris Corp.)PowerProject (ASTA Development Inc.)j ( p )Primavera Project Planner (Primavera)Project Scheduler (Scitor Corp.)Project Scheduler (Scitor Corp.)Project Workbench (ABT Corp.)

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PRACTICE EXAMPLE

A social project manager is faced with a project with the following activities:

A ti it D i ti D tiActivity Description Duration

Social work team to live in village 5w

Social research team to do survey 12w

Analyse results of survey 5w

Establish mother & child health program 14w

Establish rural credit programme 15w

Carry out immunization of under fives 4w

Draw network diagram and show the critical path Calculate project

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Draw network diagram and show the critical path. Calculate project duration.

PRACTICE PROBLEMActivity Description Durationy p1-2 Social work team to live in village 5w1-3 Social research team to do survey 12w3-4 Analyse results of survey 5w2-4 Establish mother & child health program 14w3-5 Establish rural credit programme 15w4-5 Carry out immunization of under fives 4w

24

1 5

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3

CONTOH 1:CONTOH 1:

2

B

60 KM

4

2

F

D

100 KM

60 KM

40 KM 50 KM

1 6

F

A 55 KM 25 KM5

3 E

A75 KM

55 KM 25 KM

3 E

C

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CONTOH 2

AKTIVITAS URAIAN AKTIVITAS PENDAHULUAN

WAKTU PENYELESAIAN

(HARI(HARI

A Desain daftar pertanyaan - 4

B Desain sampling - 5

C Testing daftar pertanyaan danperbaikan

A 4

D Memilih calon intervierwer B 1

E Melatih interviewer D, A 2

F Membagi wilayah kepadainterviewer

B 4interviewer

G Pelaksanaan interview C, E, F 10

H Evaluasi hasil riset G 15

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H Evaluasi hasil riset G 15