Transcript Document

OWL
Web Ontology Language
Summary
IHan HSIAO (Sharon)
2007.01.30
OWL-introduction
• Definition: a language represents knowledge
about a particular domain; a specification of
conceptualization.
• Authors: Web Ontology Working Group as
part of the W3C Semantic Web Activity
• Publish date: 2004/02/10
• Purpose: being used to publish and share sets
of terms, supporting advanced Web search,
software agents and knowledge management
• Sublanguage: OWL Lite, OWL DL, OWL Full
OWL set of documents
• The OWL Overview gives a simple introduction to OWL by
providing a language feature listing with very brief feature
descriptions;
• The OWL Guide demonstrates the use of the OWL by providing an
extended example. It also provides a glossary of the terminology
used in these documents;
• The OWL Reference gives a systematic and compact (but still
informally stated) description of all the modeling primitives of OWL;
• The OWL Semantics and Abstract Syntax document is the final
and formally stated normative definition of the language;
• The OWL Web Ontology Language Test Cases document
contains a large set of test cases for the language;
• The OWL Use Cases and Requirements document contains a set
of use cases for a web ontology language and compiles a set of
requirements for OWL.
Characteristics
• Ontology structure
• Elements: classes, properties, instances of classes, and
relationships between these instances
• Ontology mapping
• Ontology version
• OWL DL (Description Logic): support existing Description
Logic business segment and to provide computational
properties
• OWL Full: complete OWL language. It allows free mixing of
OWL with RDF Schema and, like RDF Schema, does not
enforce a strict separation of classes, properties, individuals
and data values.
• OWL Lite: It is a sublanguage of OWL DL that supports only a
subset of the OWL language constructs. abides by the same
semantic restrictions as OWL
Evolution/Changes
• OWL:
– a vocabulary extension of RDF (the Resource
Description Framework)
– a revision of the DAML+OIL web ontology
language
• Major changes:
– Namespace, RDF Schema, restrictions etc.
Concerns/Objections & Current Status
• Concerns:
– OWL not allow explicit declarations
– OWL Abstract Syntax and OWL RDF syntax rely on the
separation between object and data property names for
disambiguation, makes implementing OWL parsers difficult
– OWL Abstract Syntax cannot be translated into OWL RDF syntax
without loss of information
– Are we applying good ontologies or not?
• Cureent Status:
• 2004/05/28: project goal achieved. RDF and OWL are Semantic
Web standards that provide a framework for asset management,
enterprise integration and the sharing and reuse of data on the
Web.