mnagement project for matriculation 2011

8/2/2019 Mnagement Project for Matriculation 2011

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MATRIKULASI (3):METODE KUANTITATIVE BISNIS

MANAJEMEN PROYEK

Oleh:

MUSTARUDDIN, SE, Msi, PhD3/10/2012 1


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PROJECT MANAGEMENT

Adanya berbagai tingkat kegiatan yang dijabarkansecara detail, dan setiap kegiatan dapat dipecahmenjadi komponen yang terpisah.

Waktu, biaya, persyaratan sumber daya, aktivitaspendahulu, dan orang-orang bertanggung jawabdiidentifikasi untuk setiap kegiatan.

Program evaluation and review technique (PERT)and critical part method(CPM) adalah dua teknikyang populer untuk analisis kuantitatif yang dapatmembantu manajer untuk perencanaan,penjadwalan , pemantauan, dan pengendalianproyek-proyek besar dan kompleks.

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Six steps of PERT / CPM

Definisikan proyek dan semua aktivitas atau tugas-tugaspenting.

Mengembangkan hubungan antara kegiatan danmenentukan kegiatan yang harus mendahului aktivitasyang lain.

Gambarkan jaringan yang menghubungkan semuakegiatan.

Tetapkan waktu dan / atau perkiraan biaya untuk setiapaktivitas.

Hitunglah waktu terlama yang melalui jaringan: inidisebut bagian penting.

Gunakan jaringan untuk membantu merencanakan,menjadwalkan, memantau, dan mengendalikanproyek.

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Questions answered by PERT:

Kapan keseluruhan proyek akan selesai?Apakah orang-orang yang melaksanakan

kegiatan atau tugas penting dalam proyek,

dapat berakibat penundaan keseluruhanproyek jika mereka terlambat menyelesaikantugasnya?

Manakah kegiatan nonkritis, yaitu aktivitastertentu yang dapat ditunda pengerjaannyatanpa menunda penyelesaian keseluruhanproyek?

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Jika ada tiga waktu perkiraan, berapaprobabilitas proyek akan selesai tepat waktu?

Pada tanggal tertentu, apakah proyek sesuaijadwal, terlambat, or lebih cepat dari jadwal?

Pada tanggal tertentu, apakah biaya yangdikeluarkan adalah =, < atau > dari jumlah yang

dianggarkan?

Apakah ada cukup sumber daya yang tersediauntuk menyelesaikan proyek tepat waktu?

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Contoh Kasus:

PT. ABC adalah sebuah perusahaan penghasilberbagai jenis produk baja. Selama ini perusahaanterus menghindar untuk mengontrol polusi udara asappabrik bajanya. Namun karena desakan dari penggiatlingkungan dan pemerintah setempat, maka memaksa

perusahaan untuk mengurangi polusi udaraperusahaan dengan merencanakan untuk memasangalat pengontrol polusi udara dari asap pabriknya.Pemerintah kota telah mengultimatum perusahaanuntuk menyelesaikan pemasangan penyaring udara di

pabriknya dalam waktu 16 minggu, jika tidakpabriknya akan segera ditutup. PT. Vornis, sebagaikontraktor pelaksana pembangunan Alat PenyaringUdara (APU) menginginkan bahwa pemasangan APUberjalan lancar dan tepat waktu.

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Proyek dimulai dengan membangun komponenalatpenyaringan internal (aktivitas A), dan modifikasilantai dan atap (Modify floor and roof, sebagaiaktivitas B). Konstruksi daripada alat pengumpulasap, collection stack(aktivitas C) dapat dimulai

sesaat aktivitas A telah selesai dan pemasanganrangka dan wadah penampung (pouring the newconcrete and install frame, aktivitas D dapatdiselesaikan segera setelah lantai dan atapdimodifikasi. Setelah aktivitas C selesai dibangun,kegiatan selanjutnya adalah aktivitas E, yaitupembangunan alat pembakar dengan temperaturtinggi (high-temperature burner) dan pemasangansistem pengontrol polusi (aktivitas F) dapat segeradimulai setelah aktivitas C tersebut selesai dikerjakan.

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Alat pengontrol udara (air pollutiondevice) dapat dipasang (aktivitas G)setelah aktivitas D dan E selesai

dikerjakan. Terakhir setelah pemasangansistem kontrol dan alat pengontrol polusiudara terpasang,maka kegiatan terakhiradalah melakukan inspeksi dan tahap uji

coba alat pengontrol polusi udara yangtelah terpasang tersebut (aktivitas H).

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ACTIVITY DESCEPTION IMMIDIATEPREDECESSORS

A Build internal components -

B Modify roof and floor -

C Construct collection stack AD Pour concrete and install frame B

E Build high-temperature burner C

F Install control system C

G Install air pollution device D, E

H Inspect and test F, G

Table 1. Activities and Immediate Predecessors for PT. ABC

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Start

ABuild Internal

Components

CConstructCollection

Stack

FInstall Control

System

EBuild Burner

HInspect and

Test

Finish

BModify Roofand Floor

DPour Concrete

and Install

Frame

GInstall

Pollution

Device

Figure 1. NETWORK FOR PT. ABC

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Table 2. Time Estimates (Weeks) for PT. ABC

ACTIVITY OPTIMISTIC, a

MOSTPROBABLE,

m

PESSIMISTIC, b

EXPECTEDTIME, t

=[(a+4m+b)/6]

VARIANCE,[(b-a)/6]2

A 1 2 3 2 (3-1/6)2

B 2 3 4 3 (4-2/6)2

C 1 2 3 2 (3-1/6)2

D 2 4 6 4 (6-2/6)2

E 1 4 7 4 (7-1/6)2

F 1 2 9 3 (9-1/6)2

G 3 4 11 5 (11-3/6)2

H 1 2 3 2 (3-1/6)2

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How to Find the Critical Path

Although Table 2 indicates that the totalexpected time for all eight of PT ABCs

activities is 25 weeks, it is obvious inFigure 2 that several of tasks can betaking place simultaneously.

Critical path is the longest time path routethrough the network.

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Start

A 2 C 2 F 3

E 4 H 2 Finish

B 3 D 4 G 5

Figure 2. PT. ABCs NETWORK WITH EXPECTED ACTIVITY TIME

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To find the critical path, we need to determinethe following quantities for each activity in thenetwork:1.Earliest start time (ES): the earliest time an

activity can begin without violation ofimmediate predecessor requirements.

2.Earliest finish time (EF): the earliest time atwhich an activity can end.

3.Latest start time (LS): the latest time an

activity can begin without delaying the entireproject.4.Latest finish time (LF): the latest time an

activity can end without delaying the entireproject.

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EARLIEST TIMES

Earliest Finish time (EF) = Earliest Start time (ES) +Expected activity time (t)

Earliest Start (ES) = Largest EF of immediatepredecessors

Start

A t = 2

ES = 0 EF = 0 + 2 = 2

B t = 3

ES = 0 EF = 0 + 3 = 3

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Start

A 20 2

C 22 4

F 34 7

E 44 8

H 213 15

Finish

B 30 3

D 43 7

G 58 13

Figure 3. PT. ABCs EARLIEST START (ES) AND EARLIEST FINISH(EF) TIMES

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LATEST TIMES

Latest Start time (LS) = Latest Finish time (LF) Activity time (t)

Latest Finish time (LF) = Smallest LS of followingactivities.

For instance:Finish time for PT. ABCs project is 15 weeks,activity H has LF=15. Thus latest start for activity His: LS = LF t = 15 -2 = 13 weeks

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Start

A 20 20 2

C 2

2 4

2 4

F 3

4 7

10 13

E 4

4 8

4 8

H 2

13 15

13 15

Finish

B 3

0 3

1 4

D 4

3 7

4 8

G 5

8 13

8 13

Figure 4. PT. ABCs LATEST START (LS) AND LATEST FINISH (LF) TIMES

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Concept of Slack in Critical PathComputations:

Slack time is free time for an activity

Slack = LS ES, or Slack = LF EF

For instance:

Activity B, has 1 week of slack time since:

LS ES = 1 0 = 1, or LF EF = 4 3 = 1

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ACTIVITY ES EF LS LF SLACK, LS- ES

ONCRITICAL

PATH?

A 0 2 0 2 0 Yes

B 0 3 1 4 1 No

C 2 4 2 4 0 Yes

D 3 7 4 8 1 No

E 4 8 4 8 0 Yes

F 4 7 10 13 6 No

G 8 13 8 13 0 Yes

H 13 15 13 15 0 Yes

Table 3. PT. ABCs Schedule and Slack Times

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Start

A 20 20 2

C 2

2 4

2 4

F 3

4 7

10 13

E 4

4 8

4 8

H 2

13 15

13 15

Finish

B 30 31 4

D 43 74 8

G 5

8 13

8 13

Figure 5. PT. ABCs CRITICAL PART (A-C-E-G-H)

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Probability of Project Completion

Computing project variance is done bysumming activity variances along thecritical path.

Project variance= variances of activities on the critical path,

= 4/36 + 4/36 + 36/36 + 64/36 + 4/36

= 112/36 = 3.111 Project standard deviation = T

= Project Variance = 3.11 = 1.76 weeks

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Computing the probability of projectcompletion:

Z = Due date Expected date completion / T= 16 weeks 15 weeks / 1.76 weeks

= 0.57

Where Z is the number of standard deviations the due

date or target date lies from the mean or expected date.

Referring top the normal distribution table, we find a

probability 0f 0.71566. Thus, there is a 71.6% chance

that the pollution control equipment can be put in place

in 16 weeks or less (see Figure 6).

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0.57 Standard DeviationExpected Time is 15weeks

Probability (T 16 weeks) is71.6%

15 weeks 16 weeks Time

Figure 6. Probability of PT. ABCs Meeting the 16-weeks Deadline

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3. Convert the budget cost per activity into a cost

per time period. For example: If the budgetedcost for a given activity is Rp48 Million and theactivitys expected time is 4 weeks, thebudgeted cost per week is Rp12M.

4. Using the earliest and latest start times, find outhow much money should be spent during each

week or month to finish the project by the datedesired.

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Budgeting for PT. ABC

ACTIVITY ES LS EXPECTED TIME, t

TOTALBUDGETED COST

(RpMillion )

BUDGETED COST

PERWEEK (RpMillion )

A 0 0 2 22 1B 0 1 3 30 10

C 2 2 2 26 13

D 3 4 4 48 12

E 4 4 4 56 14F 4 10 3 30 10

G 8 8 5 80 16

H 13 13 2 16 8

Total 308

Table 4. ACTIVITY COST FOR PT. ABC

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AB

C

D

E

F

G

H

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

A

C

T

I

V

I

T

Y

WEEK

Figure 7. GANTT CART FOR PT. ABC

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W E E K

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 TTL

A 11 11

B 10 10 10 30

C 13 13 26

D 12 12 12 12 48

E 14 14 14 14 56

F 10 10 10 30

G 16 16 16 16 16 80

H 8 8 16

308TTL/W

21 21 23 25 36 36 36 14 16 16 16 16 16 8 8

TTLTO

DT

21 42 65 90 126 162 198 212 228 244 260 276 292 300 308

Table 5. BUDGETED COST (Rp Million) for PT. ABC, Using EARLIEST STARTTIMES

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b f


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W E E K

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 TTL

A 11 11

B 10 10 10 30

C 13 13 26

D 12 12 12 12 48

E 14 14 14 14 56

F 10 10 10 30

G 16 16 16 16 16 80

H 8 8 16

308

TTL/ W

11 21 23 23 26 26 26 26 16 16 26 26 26 8 8

TTLTO

DT

11 32 55 78 104 130 156 182 198 214 240 266 292 300 308

Table 6. BUDGETED COST (Rp Million) for PT. ABC, Using LATEST STARTTIMES

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Project Crashing

Shortening a project by using overtime, workingweekends, hiring extra workers, equipment, itmay possible to finish a project in less time thanis normally required.

The crash time is the shortest possible activitytime, and this requires the use of additional

resources.

The crash cost is the price of completing the

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ACTIVITY TIME

NORMAL

(WEEKS)

CRASH

COST (Rp)

NORMAL CRASH

CRASH COST

PER WEEK

CRITICAL

PATH?

A 2 1 22 JT 23 JT 1 JT YES

B 3 1 30 JT 34 JT 2 JT NO

C 2 1 26 JT 27 JT 1 JT YES

D 4 3 48 JT 49 JT 1 JT NO

E 4 2 56 JT 58 JT 1 JT YES

F 3 2 30 JT 30.5 JT 0.5 JT NO

G 5 2 80 JT 86 JT 2 JT YES

H 2 1 16 JT 19 JT 3 JT YES

TOTAL 308 JT 326.5 JT 18.5 JT

Table 7. NORMAL AND CRASH DATA FOR PT. ABC

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Start

A 20 20 2

C 2

2 4

2 4

F 3

4 7

10 13

E 4

4 8

4 8

H 2

13 15

13 15

Finish

B 3

0 3

1 4

D 4

3 7

4 8

G 5

8 13

8 13

Figure 4. PT. ABCs LATEST START (LS) AND LATEST FINISH (LF) TIMES

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$30,000

$32,000

$34,000

normal

crashCrash cost / week:= (CC NC) : (NT CT)

= ($34,000 - $30,000) : (3-1)= $2,000 per week

Cash Cost

Normal cost

1 2 3

Crash time Normal time

Crash and Normal Time and Costs for Activity BActivitycost

Time (weeks)

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TQ& C U

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mnagement project for matriculation 2011

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