Chapter 3 Knowledge Representation

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# Chapter 3 Knowledge Representation - PowerPoint PPT Presentation

Chapter 3 Knowledge Representation. Knowledge Representation. Semantic Network Network Representation Conceptual Graph Frame. Semantic Network. Network Representation. Conceptual Graph. Conceptual Graph. Case Frame. Conceptual / Graph Frame : Hotel Bed. Frame : Hotel Bed.

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### Chapter 3Knowledge Representation

Knowledge Representation
• Semantic Network
• Network Representation
• Conceptual Graph
• Frame

Chapter 3

Case Frame

Chapter 3

Frame : Bird

Chapter 3

Knowledge Representation
• important attribute : isa and instance
• relationship among attributes
• at what level of detail should the world be represented?
• Mary is Sue’s cousin. เมรี่เป็นหลานของซู
• Mary = daughter(brother(mother(Sue)))
• Mary = daughter(sister(mother(Sue)))
• Mary = daughter(brother(father(Sue)))
• Mary = daughter(sister(father(Sue)))
• Mary = daughter(sibling(parent(Sue)))

Chapter 3

Knowledge Representation

The End

• John broke the window
• Sequence ? pick up hard object , Hurl the object to the window
• Cause hand / foot to move fast and crash into the window
• Shut the window so hard that the glass breaks
• Finding the right structure
• John went to Sizzer last night. He ordered a large rare steak, paid his bill, and left.
• Did john eat dinner last night?
• John flew to New York.
• John flew a kite.
• John flew down the street.

Chapter 3

Inheritable Knowledge

The End

Chapter 3

Frame

Baseball-Player

bats: (EQUAL handed)

height: 6-1

batting-average: .252

figure 4.7

Chapter 3

Procedural Knowledge as Rules

The End

similar to figure 4.7

Chapter 3

Redundant Representation

The End

John punched Mary

Mary punched John

Chapter 3

Similarity Net

liking among set of frame

The End

Chapter 3

Representations

The End

man(Marcus)

man(Caesar)

person(Cleopatra)

X : man(X)  person(X)

y person(y)

y = Cleopatra

y = Marcus

y = Caesar

Chapter 3

Matching

The End

1. Indexing :

problems:

1. need large number of rules

2. the precondition of rule is not always obvious

2. Matching with variables

problems:

many-many match problem

many rules are matched against many elements in the state description simultaneously.

son(X,Y) and son(Y,Z) :- grandson(X,Z)

3. Complex and approximate matching

Chapter 3

Indexing

The End

Chapter 3

Logic Programming

x : pet(x)  small(x)  apartment_pet(x)

x : cat(x)  dog(x)  pet(x)

x : poodle(x)  dog(x)  small(x)

poodle(fluffy)

A Representation in Logic

The End

apartment_pet (X) :- pet (X), small (X) .

pet (X) :- cat (X) .

pet (X) :- dog (X) .

dog (X) :- poodle (X) .

small (X) :- poodle (X) .

poodle (fluffy) .

A Representation in PROLOG

Rules

Fact

Figure 6.1: Declarative and a Procedural Representation

Chapter 3

Complex Indexing

their precondition approximately match the current situation -> ELIZA

Person: Men are all alike.

ELIZA: In what way?

Person: They’re always bugging us about something or other.

ELIZA: Can you think of a specific example?

Person: Well, my boyfriend made you come here.

Person: He says I’m depressed much of the time.

ELIZA: I am sorry to hear you depressed.

Person: It’s true. I am unhappy.

ELIZA: Do you think coming here will help you not to be unhappy?

Person: I need some help, that much seems certain.

ELIZA: What would it mean to you if you got some help?

Person: Perhaps I could learn to get along with my mother.

The End

Figure 6.6: A Bit of a Dialogue with ELIZA

Chapter 3

Complex Indexing

The End

(X me Y) (X you Y)

(I remember X) (Why do remember X just now?)

(My {family-member} is Y)  (Who else in you family is Y?)

Figure 6.7: Some ELIZA-like rules

Chapter 3

Control Knowledge

The End

• Knowledge about which parts are most likely to find the goal state.
• Knowledge about which rules to apply in a given situation.
• Knowledge about the order in which to pursue subgoals.
• Knowledge about useful sequence of rules to apply.

1. Long term memory -> Rules

2. Short term memory -> Working memory

Chapter 3

Even if you're on the right track,

you'll get run over if you just sat there.