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Pertemuan 5 Knowledge Representation Issues

Matakuliah : T0264/Inteligensia Semu

Tahun : 2005

Versi : 1/0

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Learning Outcomes

Pada akhir pertemuan ini, diharapkan mahasiswa

akan mampu :

• << TIK-99 >>

• << TIK-99>>

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Outline Materi

• Materi 1

• Materi 2

• Materi 3

• Materi 4

• Materi 5

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4.1 Representations and Mappings

Mapping between Facts and Representation

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Three Representation of a Mutilated Checkerboard

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Representation of Facts

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4.2 Approaches to Knowledge Representation

Properties of a Representation System

• Representation adequacy• Inferential adequacy• Inferential efficiency• Acquisitional efficiency

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Inheritable Knowledge

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Viewing a Node as a Frame

Baseball-Player

Isa : Adult-Male

bats :(EQUAL handed)

height : 6-1

batting-average : .252

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4.3 Issues in Knowledge Representation

• Are there any basic attributes of objects ?• Are there any basic relationship among objects ?• At what level should knowledge be represented ?• How should sets be representation ?• How should knowledge be accessed ?

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4.3.1 Important Attributes

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4.3.2 Relationships among Attributes

Representing Inverses

• Reversible representations that ignore focus : Team(Pee-Wee- Reese, Brooklyn-Dodgers)

• Pairs of focused entities :- one associated with Pee Wee Reese :

team = Brooklyn-Dodgers- one associated with Brooklyn Dodgers :

team-members = Pee-Wee-Reese,...

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4.3.3 Choosing the Granularity of Representation

Suppose we are interested in the following fact :John spotted Sue.

We could represent this asspotted(agent(John),object(Sue))

Questions :Who spotted Sue ?Did John see Sue ?

We could add facts, e.g.:spotted(x,y) saw(x,y)

An alternative representation : saw(agent(John),object(Sue),timespan(briefly))

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Are There Primitive Concepts ?

Marry is Sue ‘s cousin.

• Marry = daughter(brother(mother(Sue)))• Marry = daughter(sister(mother(Sue))) • Marry = daughter(brother(father(Sue)))• Marry = daughter(sister(father(Sue)))

An alternative :• Marry = child(sibling(parent(Sue)))

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4.3.4 Representing Sets of Objects

Intensional and Extensional Representation

Extensional :

{Earth}

Intensional :{x : sun-planet(x) human-inhabited(x)}{x : sun-planet(x) nth-farthest-from-sun(x,3)}{x : sun-planet(x) nth-biggest(x,5) }

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4.3.5 Finding the Right Structures as Needed

Selecting an Initial Structure• Index structures by English words

- John flew to New York. He rode in a plane from one place to another.

- John flew a kite. * He held a kite that was up in the air.- John flew down the street.

* He moved very rapidly.- John flew into a rage. An idiom

• Index structures by concepts• Use one major clue

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4.4 The Frame Problem

A Similarity Net

CHAIR

TABLE STOOL

DESK SIDEBOARD

too big, no back

BENCH

no back,too wide

too high, no back

no knee room

drawers

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