1 / 20

# Part II - PowerPoint PPT Presentation

Part II Methods of AI. Chapter 3 Knowledge and Reasoning. Part II: Methods of AI. Chapter 3 – Knowledge Representation and Reasoning. 3.1 Summary of Logic and Reasoning. 3.2 Reasoning: Deduction Systems. 3.3 Rulebased Reasoning. 3.4 Knowledge Representation: General Issues.

Related searches for Part II

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about 'Part II' - RoyLauris

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

### Part IIMethods of AI

Chapter 3

Knowledge and Reasoning

Chapter 3 – Knowledge Representation and Reasoning

3.1 Summary of Logic and Reasoning

3.2 Reasoning: Deduction Systems

3.3 Rulebased Reasoning

3.4 Knowledge Representation: General Issues

3.5 Knowledge Representation:

Semantic Nets

3.6 Knowledge Representation:

Description Logics

3.7 Knowledge Representation:

Analogue Representation

Representation

Semantic Networks

Networks

Naive

Semantic

Nets

Naive Semantic Networks: to get started!

is-A

I.

ROBIN

BIRD

is-A

is-A

II.

CLYDE

ROBIN

BIRD

is-A

is-A

III.

CLYDE

ROBIN

BIRD

has-part

WINGS

an „unstructured“ Example

PROBLEM-1: Semantics of the SN?

PROBLEM-2: Structure of the SNs ?

Problem-3: Binary relations?

Binary Relations versus Relations with Many Arguments

Translation a la Schönfinkel (and other logicians)

EXAMPLE: Own(Owner, Ownee, Start, End)

Owner(own-1, ... )

Ownee(own-1, ... )

Start(own-1, ... )

End(own-1, ... )

TAFEL!

Translates into:

Semantic Networks: An Example for an n-ary Relation

is-A

is-A

CLYDE

ROBIN

BIRD

is-A

ownee

OWN_1

NEST_1

NEST

is-A

start-time

Spring

TIME

is-A

end-time

Fall

is-A

OWNERSHIP

SITUATION

is-A

is-A

CLYDE

ROBIN

BIRD

owns

is-A

NEST_1

NEST

Token: Nest_1

Type: Nest

Nest_1 is of type “Nest”

Generic Concept: An Arch

• Generic Concept

• Individual Concept

• Individual Object:

PARIS

An Arc de Triomphe

CAN-FLY

BIRD

property

is-A

color

CANARY

YELLOW

is-A

owns

TWEETY

SYLVESTER

 CAN-FLY (CANARY)

 CAN-FLY (TWEETY)

 SYLVESTER owns Something that can fly

 TWEETY is YELLOW

 SYLVESTER owns a CANARY

 SYLVESTER owns a BIRD

color

CANARY YELLOW

SAMGREEN

is-A

color

• Inconsistencies in SN‘s ? Pro and Con!

• Operations on SN‘s  Non-monotonic Reasoning

Just a Graphical Representation of the Predicate Calculus ?

is-A

TWEETY

BIRD

Is-A (TWEETY, BIRD)

IS-A

ROBIN

BIRD

NETWORK

PK1

Is-A(ROBIN, BIRD)

LISP

(is-A ROBIN BIRD)

• Pidgin English Semantics?

Infix: (ROBIN IS-A BIRD)

English: ‚ROBIN is a bird‘

has-part

BIRD

WINGS

is-A

is-A

CLYDE

ROBIN

is-A

studied-by

ENDANGEREDSPECIES

NATURALISTS

has-part(BIRD,WINGS)  has-part(ROBIN,WINGS)

Property(ENDANGERED SPECIES)  Property(CLYDE)

Do the naturalists study the special bird CLYDE ?

• Inheritance of Attributes

• Propagation of Parts

• Concept Centered Representation

• Semantic Distance

• Procedural Semantics of SN‘s

BUT: How to get a Declarative (Tarski) or Denotational Semantics of SN‘s?

Woods (1975): „What‘s in a Link“?

• Question: What is the Semantics of Semantic Networks?

- The Intuition of the Reader?

- The LISP-Programs operating on the SN?

compare: the early work on the semantics of

programming languages

Levesque & Mylopoulos (1977):

• Procedural Semantics

Cercone & Schubert (1979):

• Translation into First Order Predicate Logic