Knowledge Acquisition in the
Fuzzy Knowledge
Representation Framework of
a Medical Consultation System
By: Karl Boegl, Klaus-Peter Adlassnig, Yoichi Hayashi,
Thomas Rothenfluh, and Harald Leitich
MedFrame/CADIAG-IV
-
-
The predecessor: CADIAG-II
Consultation System
New Implementation
Generalized Domain Model
Fuzzy Dice
Definitions



Fuzzy Set Theory
Fuzzy Logic
Fuzzy Control
Rule-Based Fuzzy Logic System
• Rules
• antecedent
• consequent
• Fuzzifier
• inference engine
• output processor
Fuzzy Logic Example
Membership Function
tall(x) = { 0,
(height(x)-5ft.)/2ft.,
1,
1.0 +
+-------------------
|
/
|
/
|
/
|
if 5 ft. <= height (x) <= 7 ft.,
if height(x) > 7 ft. }
Person
Height
degree of tallness
--------------------------------------
/
0.5 +
if height(x) < 5 ft.,
/
0.0 +-------------+-----+------------------|
|
5.0
7.0
height, ft. ->
Billy
3' 2"
0.00
Yoke
5' 5"
0.21
Drew
5' 9"
0.38
Erik
5' 10"
0.42
Mark
6' 1"
0.54
Kareem
7' 2"
1.00
Logic Operations in Fuzzy Logic
truth (not x)
= 1.0 - truth (x)
truth (x and y) = minimum (truth(x), truth(y))
truth (x or y)
= maximum (truth(x), truth(y))
a = X is TALL and X is OLD
Another Example
old (x) = { 0,
age
c = not (X is TALL)
if age(x) < 18 yr.
(age(x)-18 yr.)/42 yr.,
1,
height
b = X is TALL or X is OLD
X is TALL
X is OLD
if 18 yr. <= age(x) <= 60 yr.
if age(x) > 60 yr. }
a
b
c
-----------------------------------------------------------------------3' 2"
65
0.00
1.00
0.00
1.00
1.00
5' 5"
30
0.21
0.29
0.21
0.29
0.79
5' 9"
27
0.38
0.21
0.21
0.38
0.62
5' 10"
32
0.42
0.33
0.33
0.42
0.58
6' 1"
31
0.54
0.31
0.31
0.54
0.46
7' 2"
45
1.00
0.64
0.64
1.00
0.00
3' 4"
4
0.00
0.00
0.00
0.00
1.00
Representation within
MedFrame/CADIAG-IV
Positive Associations
 FP
Consequent => Antecedent
 SP Antecedent => Consequent
Negative Associations
 FN
-(Consequent) => Antecedent
 SN
Antecedent => -(Consequent)
Knowledge Refinements (1 of 2)
Knowledge Refinements (2 of 2)
Project Successes
References

Title: Knowledge Acquisition in the Fuzzy Knowledge Representation
Framework of a Medical Consultation System
By: Karl Boegl, Klaus-Peter Adlassnig, Yoichi Hayashi, Thomas
Rothenfluh,
Harald Leitich
Copyright: 2001

Title: The MedFrame Project
http://medexpert.imc.akh-wien.ac.at/MedFrame/
By: Dieter Kopecky
Copyright: 2000

Title: Medical Expert Systems
http://www.computer.privateweb.at/judith/name_3.htm
By: Judith Federhofer
Copyright: 2002
(More)
References (continued)

Title: Systematized Nomenclature of Medicine
http://www.snomed.org
By: College of American Pathologists
Copyright: 2001-2003

http://www-2.cs.cmu.edu/Groups/AI/html/faqs/ai/fuzzy/part1/faq/html
Mendel, Jerry. “Uncertainty in Fuzzy Logic Systems.” University of
Southern California.
