TWINTECH COLLEGE SARAWAK
EXPERT SYSTEM
BIC 3337
ASSIGNMENT 2
1. Briefly explain the different type of knowledge.
A priori knowledge
-comes before knowledge perceived through senses, universally true
A posteriori knowledge
-knowledge verifiable through the senses, not always reliable
Procedural knowledge
-knowing how to do something
Declarative knowledge
-knowing that something is true or false
Tacit knowledge
-knowledge not easily expressed by language
2. Name the knowledge representation methods that you know.
-Production Rules
-Semantic Nets
-Schemata and Frames
-Logic
3. Name one advantage and problem with production rules.
Advantages
-simple and easy to understand
-straightforward implementation in computer
-formal foundations for some variants
Problems
-simple implementations are very inefficient
-some types of knowledge are not easily expressed
-large sets of rules become difficult to understand and maintain
4. Comment on what you know about semantic networks.
-Graphical representation for propositional information
-labeled, directed graph
-nodes represent objects, concepts, or situations
-links represent relationships
5. Explain what knowledge representation is.
-concerns with how people store and process information.
-represent knowledge in a manner as to facilitate inferencing i.e. drawing
conclusions from knowledge
-representation techniques: frames, rules, semantic networks
6. Logical expression can be divided into: Propositional logic and Predicate calculus.
Explain each of them with an example.
Propositional logic
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-represents and reasons with propositions
-propositions that link with connectives, e.g. AND, OR, NOT, IMPLIES, and
EQUIVALENT, are called compound statements
-concerns with the truthfulness of compound statements, depending on the
connectives
E.g
X
Y
XvY
--------------------------T
T
T
T
F
T
F
T
T
F
F
F
Means that either X or Y is true
Predicate calculus
-includes wider range of entities
-permits the description of relations and the use of variables
E.g
All people like dogs.
x people(x)  likes(x, dog)
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TWINTECH COLLEGE SARAWAK
7. Convert the following sentence into frame.
The aorta is a particular kind of artery which has a diameter of 2.5cm. An
artery is a kind of blood vessel. An artery always has a muscular wall, and
generally has a diameter of 0.4cm. A vein is a kind of blood vessel, but has a
fibrous wall. Blood vessels all have tubular form and contain blood
Blood-vessel
Form
tubular
contains
blood
Aorta
is-a
Diameter
Artery
2.5cm
Vein
ako
wall
Artery
ako
wall
*Diameter
Blood-vessel
muscular
0.4cm
Blood-vessel
fiborous
Tubular
Form
Blood Vessel
Contain
Blood
AKO
AKO
Artery
diameter
Vein
Has-A
Muscular Wall
IS-A
Has-A
0.4cm
Aorta
Fiborous Wall
diameter
2.5cm
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TWINTECH COLLEGE SARAWAK
8.
Elephants are large mammals. Small Nellie likes to eat apples. Like all
elephants she has trunk. Nellie lives in circus.
Elephant
subclass mammal
haspart trunk
*size large
Nellie
is-a
lives
likes
size
elephant
circus
apples
small
trunk
grass
elephant
HIPPO
has
eats
is
likes
mammal
swimming
IS-A
size
Nellie
FLOYD
lives
small
circuszoo
Dublin
likes
apples
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9.
Floyd is a small hippo who lives in Dublin zoo. Like all hippos he eats grass
and likes swimming. Most hippos live in Africa are large size.
Hippo
likes
eats
*lives
*size
swimming
grass
Africa
large
Floyd
is-a
Hippo
lives Dublin Zoo
size small
eats
HIPPO
grass
likes
swimming
IS-A
size
FLOYD
lives
small
Dublin zoo
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TWINTECH COLLEGE SARAWAK
10. Convert the following equivalences:
i) P becomes P
ii) (PvQ) becomes PQ
iii) xP becomes xP
iv) xP becomes xP
v) (PQ) becomes PvQ
vi) (PvQ)vR becomes (PvR)  (QvR)
11. Convert the following between the universal and existential quantifiers:
i) xLikes(x,Selina)
xLikes(x,Selina)
ii) wRich(w)
wRich(w)
12. Convert the following sentence into predicate calculus equivalent.
i) All lecturer likes good conduct students.
x
lecturer(x)  likes(x, good_conduct_students).
x y
lecturer(x)  likes(x, student(y, good_conduct)).
ii) Any bird with wings can fly if the bird is not fried.
x bird(x)  has_wing(x) fried(x) fly(x).
iii) All students who passed ES mid-term and won lottery are happy.
x student(x)  passed(x, ES_midterm)  won(x, lottery) happy(x).
iii) Not all students take both History and Biology.
x (student(x)   (take(x, History) take(x, Biology))).
x(student(x)   (take(x, History) take(x, Biology))).
iv) All people like dogs.
x people(x)  likes(x, dog)
v) Some people like cats.
x people(x)  likes(x, cat)
vi) Some dogs do not like any cats.
x y
dog(x)  likes(x, cat(y))
vii) People who like cats are nice but are not happy.
x people(x)  likes(x, cats)
viii)Anyone who studies or is lucky can pass all his exams.
x y study(x) v lucky(x)  pass(x,y)
ix) John did not study, but John is lucky.
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study(John)  lucky(John)
x) Anyone who is lucky wins the lottery.
x lucky(x)  wins(x, lottery)
xi) All basketball players are tall.
x (basketballPlayer(x)  tall(x)
xii) Some people like garlic.
x (person(x)  likes(x, garlic))
xiii)Every man likes a tasty apple.
x (apple(x)  tasty(x))
xiv) No apple is blue.
x (apple(x)  blue(x))
xv) Every apple is either green or red.
x (apple(x)  green(x) v red(x))
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