[Semantic] 04. Web Ontology Language : OWL

• OWL Family Tree
   
  
  
  
  • OIL : European language
    • frame 기반의 언어를 기반을 둠
    • formal rigour을 강조함
    • Description logic 들로 구성된 semantic
    • RDFS 기반의 syntax
      
       
      
  • DAM-ONT : USA language
    • RDFS을 OO의 Constructor을 통하여 확장, frame기반의 언어
    • Semantic 표준과는 약간 거리가 있다
      - Machine interpretation , Human interpretation에 문제
      
       
      
  • DAM+OIL : EU/US Committe
    • DAML-ONT와 OIL을 수용
    • RDFS 기반 Syntax의 DL
    • W3C에 WebOnt로서 기초가 됨
      
       
      
  • OWL
    • W3C 권고안
    • DAML+OIL 에 기초를 둠
    • RDF/XML 과 연속성을 가짐
    • Formal Semantic - Frist Order/ Reationship with RDF

• OWL Layering
• OWL Full - OWL Syntax 와 RDF의 조합
• Very high expressiveness
• Losing tractability
• All syntactive freedom of RDF
• OWL DL - FOL fragment로 제한 (DAML+OIL과 비슷함)
• Maximal expressiveness
• While maintaining tractability
• Standard formalisation in a DL
• OWL Lite - OWL DL의 간단한 subset
• Classificaiton hierarchy
• Simple constraints
  
  

• OWL Full
• OWL vocabulary을 사용하는데 있어 제한이 없다
• Classes as instance
• RDF style model theory
• Reasoning using FOL engines
• Semantics should correspond with OWL DL for suitably restricted KBs
• OWL DL
• 제한적인 OWL vocabulary 사용가능
• No classes as instances
• Defined by abstract syntax + mapping to RDF
• Standard DL/FOL model theory
• 장점들
• Well defined 'semantics'
• Formal properties well understood
• Known reasoning algorithms
• Implemented systems
• OWL Lite
• DL과 비슷하지만, Fewer constructs..
• No explicit negation / union
• Restricted cardinality (zeor or on)
• No nominals (oneOf)
• Semantics as per DL
• Reasoning via standard DL engines (+datatypes)
• e.g., FaCT, RACER, Cerebra, Pellet