Operations Management
For Competitive Advantage
1
ninth edition
Ákvarðanatré (Decision Trees)






Notuð til að kortleggja flóknar ákvarðanir
sem einkennast af óvissu / áhættu
Tvö tákn notuð:
Kassi merkir ákvarðanataka
Bolla merkir hendingu / atburði með líkindum
Væntigildi reiknuð, ákvörðun með hæsta
væntigildið valin
CHASE
AQUILANO
JACOBS
©The McGraw-Hill Companies, Inc., 2001
Operations Management
For Competitive Advantage
2
ninth edition
Dæmi um ákvarðanatré
A glass factory specializing in crystal is experiencing a
substantial backlog, and the firm's management is considering
three courses of action:
A) Arrange for subcontracting,
B) Construct new facilities.
C) Do nothing (no change)
The correct choice depends largely upon demand, which may
be low, medium, or high. By consensus, management
estimates the respective demand probabilities as .10, .50, and
.40.
CHASE
AQUILANO
JACOBS
©The McGraw-Hill Companies, Inc., 2001
Operations Management
For Competitive Advantage
3
ninth edition
Dæmi um ákvarðanatré :
Hagnaðartaflan (“The Payoff Table”)
The management also estimates the profits when
choosing from the three alternatives (A, B, and C) under
the differing probable levels of demand. These costs, in
thousands of dollars are presented in the table below:
A
B
C
0.1
Low
10
-120
20
CHASE
0.5
Medium
50
25
40
AQUILANO
JACOBS
0.4
High
90
200
60
©The McGraw-Hill Companies, Inc., 2001
Operations Management
For Competitive Advantage
ninth edition
4
Dæmi um ákvarðanatré : Þrep 1. Teikna
ákvarðanirnar
A
B
C
CHASE
AQUILANO
JACOBS
©The McGraw-Hill Companies, Inc., 2001
Operations Management
For Competitive Advantage
5
ninth edition
Dæmi um ákvarðanatré : Þrep 2. Bæta við
mögulegum atburðum, líkum á þeim og hagnaði.
High demand (.4)
Medium demand (.5)
Low demand (.1)
A
High demand (.4)
B
Medium demand (.5)
Low demand (.1)
$90k
$50k
$10k
$200k
$25k
-$120k
C
High demand (.4)
Medium demand (.5)
Low demand (.1)
CHASE
AQUILANO
JACOBS
$60k
$40k
$20k
©The McGraw-Hill Companies, Inc., 2001
Operations Management
For Competitive Advantage
6
ninth edition
Dæmi um ákvarðanatré : Þrep 3.
Ákvarða væntigildi hverrar ákvörðunar
$90k
$50k
$10k
High demand (.4)
Medium demand (.5)
$62k
Low demand (.1)
A
EVA=.4(90)+.5(50)+.1(10)=$62k
CHASE
AQUILANO
JACOBS
©The McGraw-Hill Companies, Inc., 2001
Operations Management
For Competitive Advantage
7
ninth edition
Dæmi um ákvarðanatré : Þrep 4. Hæsta
væntigildi => bestu ákvörðun
High demand (.4)
Medium demand (.5)
$62k
A
B
$80.5k
Low demand (.1)
High demand (.4)
Medium demand (.5)
Low demand (.1)
$90k
$50k
$10k
$200k
$25k
-$120k
C
High demand (.4)
$46k
Medium demand (.5)
Low demand (.1)
$60k
$40k
$20k
Alternative B generates the greatest expected profit, so our
choice is B or to construct a new facility.
CHASE
AQUILANO
JACOBS
©The McGraw-Hill Companies, Inc., 2001
Operations Management
For Competitive Advantage
8
ninth edition
Önnur sjónarmið



Eru líkur rétt metnar? Næmnigreining!
Er hægt að “kaupa” meiri fullvissu (t.d. afla
öruggari upplýsinga um eftirspurn)?
Áhættufælni (“Risk Aversion”)
CHASE
AQUILANO
JACOBS
©The McGraw-Hill Companies, Inc., 2001