Product Design of ITATS
Decision Making
Module based on Operation Management, 9e
PowerPoint presentation to accompany Heizer/Render Heizer /Render Lecturer: F. Priyo Suprobo, ST, MT © 2008 Prentice Hall, Inc.
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Permasalahan Konsultan desain HCIDHCID-ITATS bekerja untuk Healthy Pillow Company sedang mengusulkan rancangan Alas Tidur Kesehatan yang mutakhir dengan beberapa pilihan. pilihan. Bekerjasama dengan tenaga pemasaran Healthy Pillow dirumuskanlah beberapa alternatif berikut peluang keberhasilannya sebagai berikut berikut::
Selanjutnya, terhadap alternatif yang ada, apakah saran Anda sebagai staf HCIDHCID-ITATS untuk Healthy Pillow ini?
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Outline ; Proses Keputusan ; Dasar Dasar--Dasar Pengambilan Keputusan ; Tabel Keputusan
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Outline – Continued ; Tipe Pengambilan Keputusan ; Pengambilan Keputusan dalam Ketidakpastian ; Pengambilan Keputusan dengan Resiko ; Pengambilan Keputusan dalam Kepastian ; Expected Value of Perfect Information (EVPI) © 2008 Prentice Hall, Inc.
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Outline – Continued ; Pohon Keputusan ; Pohon Keputusan Sederhana ; Pohon Keputusan yang lebih Kompleks
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Learning Objectives When you complete this module you should be able to: 1. Membuat sebuah pohon keputusan sederhana 2. Membangun tabel keputusan 3. Menjelaskan kapan menggunakan salah satu tipe dalam pengambilan keputusan 4. Menghitung expected monetary value (EMV) © 2008 Prentice Hall, Inc.
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Learning Objectives When you complete this module you should be able to: 5. Menghitung expected value of perfect information (EVPI) 6. Mengevaluasi titik titik--titik dalam Pohon Keputusan 7. Membuat Pohon Keputusan dengan penyelesaian berurutan
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The Decision Process in Operations 1. Clearly define the problems and the factors that influence it 2. Develop specific and measurable objectives 3. Develop a model 4. Evaluate each alternative solution 5. Select the best alternative 6. Implement the decision and set a timetable for completion © 2008 Prentice Hall, Inc.
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Fundamentals of Decision Making 1. Terminologi/Istilah Terminologi/Istilah:: a. Alternative – Sebuah tindakan atau strategi yang dapat dipilih oleh pengambil keputusan b. State of nature/Kondisi nature/Kondisi Alami – Sebuah kejadian atau kondisi dimana pengambil keputusan hanya punya sedikit kendali atau tidak sama sekali © 2008 Prentice Hall, Inc.
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Fundamentals of Decision Making 2. Symbols dalam Pohon Keputusan Keputusan:: a. – Sebuah titik keputusan dimana terdapat satu atau lebih alternatif yang dapat dipilih b. { – sebuah simbol titik kondisi alami yang mungkin terjadi
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Decision Tree Example Titik Keputusan
Titik Kondisi Alami Pasar sesuai harapan
Pasar tidak sesuai harapan Pasar sesuai harapan Desain TPC Pasar tidak sesuai harapan
Figure A.1 © 2008 Prentice Hall, Inc.
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Decision Table Example Alternatives Desain UMPC Desain Tablet PC Do nothing
Kondisi Alami Pasar sesuai Pasar TidakSesuai $200,000 –$180,000 $100,000 –$ 20,000 $ 0 $ 0
Table A.1
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Decision-Making DecisionEnvironments ; Pengambilan Keputusan dalam Ketidakpastian ; Kondisi alami tidak dapat diperkirakan
; Pengambilan Keputusan dengan Resiko ; Beberapa kondisi alami mungkin terjadi ; Tetapi masingmasing-masing pilihan tetap berpeluang
; Pengambilan Keputusan dalam Kepastian ; Kondisi alami diketahui pasti
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Ketidakpastian 1. Maximax ; Find the alternative that maximizes the maximum outcome for every alternative ; Pick the outcome with the maximum number ; Highest possible gain ; This is viewed as an optimistic approach © 2008 Prentice Hall, Inc.
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Ketidakpastian 2. Maximin ; Find the alternative that maximizes the minimum outcome for every alternative ; Pick the outcome with the minimum number ; Least possible loss ; This is viewed as a pessimistic approach © 2008 Prentice Hall, Inc.
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Ketidakpastian 3. Equally likely (Sama rata) ; Find the alternative with the highest average outcome ; Pick the outcome with the maximum number ; Assumes each state of nature is equally likely to occur
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Uncertainty Example Kondisi alamiah Pasar sesuai Alternatives Harapan
Pasar tidak sesuai
Maximum in Row
Minimum in Row
Row Average
Desain UMPC
$200,000
-$180,000
$200,000 -$180,000
$10,000
Desain Tablet PC
$100,000
-$20,000
$100,000
-$20,000
$40,000
Do nothing
$0
$0
$0
$0
$0
Maximax
Maximin
Equally likely
1. Maximax choice is to construct a UMPC Design 2. Maximin choice is to do nothing 3. Equally likely choice is to construct a Tablet PC © 2008 Prentice Hall, Inc.
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Beresiko ; Each possible state of nature has an assumed probability ; States of nature are mutually exclusive ; Probabilities must sum to 1 ; Determine the expected monetary value (EMV) for each alternative
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Expected Monetary Value EMV (Alternative i) = (Payoff of 1st state of nature) x (Probability of 1st state of nature) + (Payoff of 2nd state of nature) x (Probability of 2nd state of nature) +…+ (Payoff of last state of nature) x (Probability of last state of nature)
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EMV Example Table A.3
Kondisi Alamiah
Alternatives
Pasar sesuai Harapan
Pasar tidak sesuai harapan
Desain UMPC (A1)
$200,000
-$180,000
Desain Tablet PC (A2)
$100,000
-$20,000
Do nothing (A3)
$0
$0
Probabilities
.50
.50
1. EMV(A EMV(A1) = (.5)($200,000) + (.5)((.5)(-$180,000) = $10,000 2. EMV(A EMV(A2) = (.5)($100,000) + (.5)((.5)(-$20,000) = $40,000 3. EMV(A EMV(A3) = (.5)($0) + (.5)($0) = $0 © 2008 Prentice Hall, Inc.
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EMV Example Table A.3
Alternatives
Kondisi Alamiah Pasar Pasar tidak Sesuai Harapan Sesuai Harapan
Desain UMPC (A1)
$200,000
-$180,000
Desain Tablet PC (A2)
$100,000
-$20,000
Do nothing (A3)
$0
$0
Probabilities
.50
.50
1. EMV(A EMV(A1) = (.5)($200,000) + (.5)((.5)(-$180,000) = $10,000 2. EMV(A EMV(A2) = (.5)($100,000) + (.5)((.5)(-$20,000) = $40,000 3. EMV(A EMV(A3) = (.5)($0) + (.5)($0) = $0 Best Option © 2008 Prentice Hall, Inc.
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Kepastian ; Is the cost of perfect information worth it? ; Determine the expected value of perfect information (EVPI)
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Expected Value of Perfect Information EVPI is the difference between the payoff under certainty and the payoff under risk Expected value Maximum with perfect EVPI = – EMV information Expected value with perfect information (EVwPI)
= (Best outcome or consequence for 1st state of nature) x (Probability of 1st state of nature) + Best outcome for 2nd state of nature) x (Probability of 2nd state of nature) + … + Best outcome for last state of nature) x (Probability of last state of nature)
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EVPI Example 1. Hasil terbaik untuk kondisi alamiah Pasar yang sesuai Harapan adalah Desain UMPC dengan payoff of $200,000 $200,000.. Hasil terbaik untuk Pasar yang Tidak sesuai Harapan adalah ““do do nothing” dengan payoff of $0 $0.. Expected value with perfect = ($200,000)(.50) + ($0)(.50) = $100,000 information (EVwPI)
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EVPI Example 2. Maximum EMV is $40,000 $40,000,, yang adalah hasil harapan terbaik tanpa informasi sempurna. Sehingga: Sehingga: EVPI = EVwPI – Maximum EMV = $100,000 – $40,000 = $60,000 The most the company should pay for perfect information is $60,000 © 2008 Prentice Hall, Inc.
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Pohon Keputusan ; Information in decision tables can be displayed as decision trees ; A decision tree is a graphic display of the decision process that indicates decision alternatives, states of nature and their respective probabilities, and payoffs for each combination of decision alternative and state of nature ; Appropriate for showing sequential decisions © 2008 Prentice Hall, Inc.
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Decision Trees
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Pohon Keputusan 1. Mendefinisikan Masalah 2. Menggambar Pohon Keputusan 3. Menentukan Peluang bagi Kondisi Alamiah 4. Memperkirakan imbalan bagi setiap kombinasi alternatif keputusan dan kondisi alamiah yang mungkin 5. Menyelesaikan permasalahan dengan mengerjakan dari belakang ke depan melalui perhitungan EMV untuk masingmasingmasing titik kondisi alamiah. © 2008 Prentice Hall, Inc.
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Decision Tree Example EMV for node 1 = $10,000
= (.5)($200,000) + (.5)( (.5)(--$180,000) Payoffs Pasar sesuai harapan (.5)
1
Pasar tidak sesuai (.5) Pasar sesuai harapan (.5)
Desain Tablet PC
2
EMV for node 2 = $40,000 Figure A.2
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Pasar tidak sesuai (.5)
$200,000 -$180,000 $100,000 -$20,000
= (.5)($100,000) + (.5)( (.5)(--$20,000)
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Complex Decision Tree Example
Figure A.3 © 2008 Prentice Hall, Inc.
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Complex Example 1. Given favorable survey results EMV(2) = (.78)($190,000) + (.22)((.22)(-$190,000) = $106,400 EMV(3) = (.78)($90,000) + (.22)((.22)(-$30,000) = $63,600
The EMV for no plant = -$10,000 so, if the survey results are favorable, build the large plant
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Complex Example 2. Given negative survey results EMV(4) = (.27)($190,000) + (.73)((.73)(-$190,000) = -$87,400 EMV(5) = (.27)($90,000) + (.73)((.73)(-$30,000) = $2,400
The EMV for no plant = -$10,000 so, if the survey results are negative, build the small plant
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Complex Example 3. Compute the expected value of the market survey EMV(1) = (.45)($106,400) + (.55)($2,400) = $49,200
4. If the market survey is not conducted EMV(6) = (.5)($200,000) + (.5)((.5)(-$180,000) = $10,000 EMV(7) = (.5)($100,000) + (.5)((.5)(-$20,000) = $40,000 The EMV for no plant = $0 so, given no survey, build the small plant © 2008 Prentice Hall, Inc.
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The end Pokok Bahasan Selanjutnya: Teknik Peramalan (F O R E C A S T I N G)
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