온톨로지 개념 및 표현언어

온톨로지 개념 및온톨로지 표현언어

시맨틱 웹 VoCamp 서울 : 여름

김동범 ([email protected])아이네크 시맨틱사업팀

http://www.dbdb.kr, @eastkim on twitter2009.05.29

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시맨틱 웹 VoCamp 서울 : 여름 - 2 -

시맨틱 웹 표준의첫 번째 Layer

SemanticAspect

WebAspect

The Role of RDF on Semantic Web


“The author of the page is Ora”

triple(author, page, Ora)

Why RDF model is different from the XML model ?

Tim Berners-Lee (1998), http://www.w3.org/DesignIssues/RDF-XML

page

Orahas author


How would this information be typically represented in XML?

<author> <uri>page</uri> <name>Ora</name></author>

<document href=“page”> <author>Ora</author></document>

<document> <details> <uri>href=“page”</uri> <author> <name>Ora</name> </author> </details></document>

<document> <author> <uri>href=“page”</uri> <details> <name>Ora</name> </details> </author></document>

<document href=“http://www.w3.org/test/page” author=“Ora” />

or may be

or may be

or may be


What is the author of page?

<v> <x> <y>a=“pppp”</y> <z> <w>qqqqq</w> </z> </x></v>

page

Orahas author

a cb


In RDF Graph

<Description about="http://www.w3.org/test/page" Author ="Ora" />

page

Orahas author

<?xml version="1.0"?> <Description about="http://www.w3.org/test/page“>

<s:Author ="http://www.w3.org/staff/Ora" /> </Description>


The RDF Graph displays the same thing

<Description about=“x" y=“z” />

x zy

<?xml version="1.0"?> <Description about=“x“>

<y =“z” /> </Description>


분산된 데이터의 웹에서… .

page Orahas author

글을 작성하다

영화 ‘ xxx’ 에출연하다

xxx

plays in

Ora 는 ‘ page’ 의 저자이고 , 영화

‘ xxx’ 에 출연했다

통합문서


"formal, explicit specification of a shared conceptualization“

“ 공유된 개념에 대한 형식적이고 , 명시적인 명세…… ??”

Tom Gruber (1993)

What is ontology?


존재론 in Philosophy

What is ontology?

즉 , 온톨로지는 “존재하는 것들에 대한 설명”

그럼 존재하는 것이란 무엇일까요 ?


Thing

존재하는 것


Thing

스무고개…

정답 !! >>

lives inAsia

Person

type Korea

partOf

Asia

INEKworks at

3X

age

Corporation

type

??

name

김동범


Thing 에 제약 ( 속성 , 관계 ) 을 가함으로써 개념을 정의

제약이 많다 = 표현력 (Expressivity) 이 풍부하다

객관적인 형식과 그 형식이 동작하는 방식을 규정 (formal)

이와 같이 온톨로지는… .


표현력에 따른 온톨로지

Lightweight ontologies Concepts

Relationships between Concepts

IS-A Hierarchy

Heavyweight ontologies type constraints on relations

Cardinality constraints

Axioms

RDF, RDFS, OWL Lite OWL DL


온톨로지 표현 언어RDF, RDFS, OWL


RDF(S) Developed by W3C (1999, 02)

Ontology Inference Layer : OIL Developed by group of European researchers (2000, 01)

DAML Ontology Language : DAML-ONT Developed by US researchers working in DAML program (2000, 10)

Effort merged in DAML+OIL Developed by EU/US joint committee (2000, 12)

W3C Web Ontology group : OWL W3C standard based on DAML+OIL (2002, 02)

History of Ontology Language


RDF stands for

Resource

Description

Framework

: URI 를 갖는 모든 것 ( 웹 페이지 , 이미지 , 동영상 등 )

: 자원 (Resource) 들의 속성 , 특성 , 관계

: 위의 것들을 기술하기 위한 모델 , 언어 , 문법


RDF 데이타 모델

Subject ObjectPredicate

: Triple Model

http://www.dbdb.kr/rdf_tutorial

온톨로지 개념 및 표현언어title

DongBeom Kimauthor

example

<?xml version=“1.0”>

<RDF> <Description about=“http://www.dbdb.kr/rdf_tutorial”> <author>DongBeom Kim</author> <homepage> 온톨로지 개념 및 표현언어 </homepage> </Description></RDF>


Movie ListURI : http://movie.naver.com/


RDF Example

title director country runtime genre reviewer

007 퀀텀 오브 솔러스 마크 포스터 미국 106 분 액션 genie

아내가 결혼했다 정윤수 한국 119 분 멜로 eastkim

… … … … … …


<RDF xmlns:rdf=“http://www.w3.org/1999/02/22-rdf-syntax-ns#” xmlns:movie=“http://movie.naver.com/”>

<Description rdf:about=“http://movie.naver.com/007quantumofsolace”> <movie:title>007 퀀텀 오브 솔러스 </movie:title> <movie:director> 마크 포스터 </movie:director> <movie:country> 미국 </movie:country> <movie:runtime>106 분 </movie:runtime> <movie:reviewer>genie</movie:reviewer> </Description>

<Description rdf:about=“http://movie.naver.com/2husbands”> <movie:title> 아내가 결혼했다 </movie:title> … </Description></RDF>


RDF Main Elements

<rdf:RDF> ElementRDF 문서의 root Element

<rdf:Description> Elementabout 속성을 가진 resource 를 식별 ( 기술 ) 하기 위해 사용Resource 를 기술하기 위한 여러 Element(title, director, etc) 를 포함


<RDF xmlns:rdf=“http://www.w3.org/1999/02/22-rdf-syntax-ns#” xmlns:movie=“http://movie.naver.com/”>

.

. Description goes here

.

</RDF>


<Description rdf:about=“http://movie.naver.com/2husbands”> <movie:title> 아내가 결혼했다 </movie:title> … </Description>


RDF Main Elements

Properties as Attributes

<Description rdf:about=“http://movie.naver.com/007quantumofsolace” movie:title=“007 퀀텀 오브 솔러스” movie:director=“ 마크 포스터” movie:country=“ 미국” movie:runtime=“106 분” movie:reviewer=“genie”/>

Properties as Resources



RDF Main Elements

rdf:Alt, Bag, Description, ID, List, Property, Statement, Seq, XMLLiteral

about, first, nodeID, object, parseType, predicate, resource, rest, subject, type, value, nil

rdfs:Class, Container, ContainerMembershipProperty, Datatype, Literal, Resource

comment, domain, isDefinedBy, label, member, range, sellAlso, subClassOf, subPropertyOf


More Expressive than RDF(S)

Adds more vocabularies for describing properties

and classes

Based on Description Logic

W3C Recommendation (2004.02)

OWL (Web Ontology Language)


OWL 의 하위 언어들 OWL Lite

Subset of DL light-weight 한 ontology 구축에 적합

OWL DL Support Description Logic segment Has properties for reasoning systems heavy-weight 한 ontology 구축에 적합

OWL Full Union of OWL and RDFS Allow free mixing of OWL with RDF Schema Not enforce a strict separation of classes, properties, individuals

OWL Lite ⊂ DL Full⊂


OWL Lite Contructions (1)

RDF Schema Features:

Class rdf:Property rdfs:subClassOf rdfs:subPropertyOf rdfs:domain rdfs:range Individual

(In)Equality

equivalentClass equivalentProperty sameIndividualAs differentFrom allDifferent


OWL Lite Contructions (2)

Property Type Restrictions: allValuesFrom someValuesFrom

Class Intersection intersectionOf

Datatypes

Restricted Cardinality– minCardinality (only 0 or 1)– maxCardinality(only 0 or 1)– cardinality (only 0 or 1)

Property Characteristics: inverseOf transitiveProperty symmetricProperty functionalPropety InverseFunctionalProperty


Property type restrictions<owl:Restriction> <owl:onProperty rdf:resource="#hasParent" /> <owl:allValuesFrom rdf:resource="#Human" /></owl:Restriction>

owl:allValuesFrom

owl:someValuesFrom

X YhasParent

Y 는 모두 Human

<owl:Restriction> <owl:onProperty rdf:resource="#hasParent" /> <owl:someValuesFrom rdf:resource="#Physician"/></owl:Restriction>

: 부모중 적어도 한명은 Physician 이다 .


Property type restrictions owl:inverseOf

owl:symmetricProperty

if hasChild inverseOf hasParent and Deborah hasParent Louisethen Louise hasChild Deborah

owl:transitiveProperty

if pair(X,Y), pair(Y,Z) are instances of transitive property P, then pair(X,Z) is also instance of P

if pair(X,Y) is an instance of P, then pair(Y,X) is also instance of P


OWL DL, FULL Contructions (2) Class Axioms:

oneOf disjointWith equivalentClass

(applied to class expressions) rdfs:subClassOf

(applied to class expressions)

Arbitrary Cardinality: minCardinality maxCardinality cardinality

Boolean Combinations of Class Expressions:– unionOf– intersectionOf– complementOf

Filler Information:– hasValue


OWL DL 표현 예제

<owl:Class rdf:ID="Adult"> <owl:intersectionOf rdf:parseType="Collection"> <owl:Class rdf:about="#Person"/> <owl:restriction> <owl:onProperty rdf:resource="#age"/> <owl:someValuesFrom df:resource="http://www.w3.org/TR/@@/owl-ex-dt#over19"/> </owl:Restriction> </owl:intersectionOf></owl:Class>

Adult = Person ∩ $ age.over19

owl:intersectionOf links a class to a list of class description represent the “AND”


OWL DL 표현 예제 owl:inverseOf

owl:FunctionalProperty

<owl:ObjectProperty rdf:ID=“hasChild”> <owl:inverseOf rdf:resource=“#hasParent”/></owl:ObjectProperty>

<owl:FunctionalProperty rdf:ID="husband"> <rdfs:domain rdf:resource="#Woman" /> <rdfs:range rdf:resource="#Man" /></owl:FunctionalProperty>

<owl:ObjectProperty rdf:ID="husband"> <rdf:type rdf:resource="&owl;FunctionalProperty" /> <rdfs:domain rdf:resource="#Woman" /> <rdfs:range rdf:resource="#Man" /></owl:ObjectProperty>


OWL DL 표현 예제 owl:TransitiveProperty

owl:SymmetricProperty

<owl:TransitiveProperty rdf:ID="subRegionOf"> <rdfs:domain rdf:resource="#Region"/> <rdfs:range rdf:resource="#Region"/></owl:TransitiveProperty>

<owl:SymmetricProperty rdf:ID="friendOf"> <rdfs:domain rdf:resource="#Human"/> <rdfs:range rdf:resource="#Human"/></owl:SymmetricProperty>

감사합니다 !

시맨틱 웹 VoCamp 서울 : 여름

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온톨로지 개념 및 표현언어

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