Title: W3C Tracking OWL
1W3C Tracking OWL
- David De Roure
- GGF Semantic Grid Research Group
- www.semanticgrid.org/GGF
2XMLRDF Basics
- URI - Uniform Resource Identifier
- XML - eXtensible Markup Language
- XML Namespaces
- XML Schema
- RDF - Resource Description Framework
- RDF Schema
3Resource Description Framework
4Not Rocket Science
Is this rocket science? Well, not really. The
Semantic Web, like the World Wide Web, is just
taking well established ideas, and making them
work interoperability over the Internet. This is
done with standards, which is what the World Wide
Web Consortium is all about. We are not inventing
relational models for data, or query systems or
rule-based systems. We are just webizing them. We
are just allowing them to work together in a
decentralized system - without a human having to
custom handcraft every connection. -- Tim
Berners-Lee, Business Case for the Semantic Web,
http//www.w3.org/DesignIssues/Business
5Jargon interop
- In science, models provide interoperability
across jargons - Mathematical models equations of a system
- Physical models sticks and balls of the atom
- Virtual models the visualization of a complex
data set - INFORMATION MODELS taxonomies and thesauri
6Ontologies
- Ontologies extend thesaurus information models to
provide - Semantic restrictions on property relations
- Must have vs. May have vs. Doesnt have
- Has some vs. has N vs. has 1
- Some vs. All property restrictions
- Formal underpinnings
- Note rules, logics, proofs are parts of
ontologies, but not yet at a consensus level
for standardization
7RDFS
- The Resource Description Framework (RDF) was the
first language specified by the W3C for
representing semantic information about arbitrary
resources. - RDF Schema (RDFS) is a W3C candidate
recommendation for an extension to RDF to
describe RDF vocabularies. - RDFS can be used to create ontologies, but it is
purposefully lightweight, with less expressive
power than OWL.
8Other ontology efforts
- DAML - DARPA Agent Markup Language
- DAML-ONT
- MCF - Meta Content Framework.
- Ontobroker
- On-To-Knowledge
- OIL - Ontology Inference Layer
- SHOE - Simple HTML Ontology Extensions
- XOL
9DAMLOIL
- Researchers, including many of the main
participants in both the OIL and DAML-ONT
efforts, got together in the Joint US/EU ad hoc
Agent Markup Language Committee to create a new
web ontology language - This language DAMLOIL built on both OIL and
DAML-ONT, was submitted to the W3C as a proposed
basis for OWL, and was subsequently selected as
the starting point for OWL
10DAMLOIL uptake
- DAMLOIL is already the most used ontology
language in history - Sept 30, 02 Crawler finds 5M DAML statements on
20,000 web pages - Doesnt include many instance KBs tied to
ontologies - Doesnt include many very large RDFS-based KBs
that include some OWL - OWL is being supported by large corporation labs
- Web tool developers IBM, HP, Sun, Intel, Fujitsu
- Content providers Daimler-Chrysler, Nokia,
Motorola, EDS, Agfa - OWL is starting to be used by thesaurus
distributors - C.f. National Cancer Institute metathesaurus to
be released in OWL
11OWL Web Ontology Language
12OWL Extends RDF
- RDF-schema
- Class, subclass
- Property, subproperty
- Restrictions
- Range, domain
- Local, global
- Existential
- Cardinality
Combinators Union, Intersection Complement Symme
tric, transitive Mapping Equivalence Inverse
13OWL is not
- OWL is not a knowledge representation language
per se - Definitely not The standard for KR
- OWL is not a Description Logic per se
- It does support DL idioms
- E.g. Lymphoma is restricted to be a subClassOf
those things whose disease property is Cancer
- It includes a subset which is complete, and
decidable - But, it will allow uses that DLs do not
14OWL Documents
- Web Ontology Language (OWL) Guide Version 1.0,
W3C Working Draft, 26 February 2003 - Requirements for a Web Ontology Language. W3C
Working Draft, 08 July 2002. - Feature Synopsis for OWL Lite and OWL. Deborah L.
McGuinness and Frank van Harmelen. W3C Working
Draft, 29 Jul 2002. - OWL Web Ontology Language 1.0 Reference. Mike
Dean and Guus Schreiber. W3C Working Draft, 3
February 2003. - OWL Web Ontology Language 1.0 Abstract Syntax.
Peter F. Patel-Schneider, Ian Horrocks, and Frank
van Harmelen. W3C Working Draft 29 July 2002. - Model-Theoretic Semantics for OWL, Peter F.
Patel-Schneider, Partick Hayes, and Ian Horrocks.
3 February 2003
15OWL Guide
- This document demonstrates the use of the OWL
language to - formalize a domain by defining classes and
properties of those classes, - define individuals and assert properties about
them, and - reason about these classes and individuals to the
degree permitted by the formal semantics of the
OWL language.
16The Species of OWL
- OWL Lite supports those users primarily needing a
classification hierarchy and simple constraint
features. It should be simpler to provide tool
support for OWL Lite than its more expressive
relatives, and provides a quick migration path
for thesauri and other taxonomies.
17The Species of OWL
- OWL DL supports those users who want the maximum
expressiveness without losing computational
completeness and decidability of reasoning
systems. OWL DL was designed to support the
existing Description Logic business segment.
18The Species of OWL
- OWL Full is meant for users who want maximum
expressiveness and the syntactic freedom of RDF
with no computational guarantees. It allows an
ontology to augment the meaning of the
pre-defined (RDF or OWL) vocabulary.
19Expressiveness
- OWL Lite supports cardinality constraints, but it
only permits cardinality values of 0 or 1. - In OWL DL, a class cannot also be an individual
or property, a property can not also be an
individual or class. - In OWL Full a class can be treated simultaneously
as a collection of individuals and as an
individual in its own right.
20See some OWL!
- Fragments from the Wine Ontology example in the
OWL Guide
21Namespaces
- ltrdfRDF xmlns http//www.example.org/wine
- xmlnsvin http//www.example.org/wine
- xmlnsfoodhttp//www.example.org/food
- xmlnsowl "http//www.w3.org/2002/07/owl"
- xmlnsrdf http//www.w3.org/1999/02/22-rdf-synta
x-ns - xmlnsrdfshttp//www.w3.org/2000/01/rdf-schema
- xmlnsxsd "http//www.w3.org/2000/10/XMLSchema"
gt
22Ontology header
- ltowlOntology rdfabout"http//www.example.org/wi
ne"gt - ltrdfscommentgtAn example OWL ontologylt/rdfscomm
entgt - ltowlpriorVersion rdfresource"http//www.exampl
e.org/wine-2102.owl"/gt - ltowlimports rdfresource"http//www.example.org
/food.owl"/gt - ltrdfslabelgtWine Ontologylt/rdfslabelgt
- ...
- lt/owlOntologygt
23Simple classes
- ltowlClass rdfID"Winery"/gt
- ltowlClass rdfID"Region"/gt
- ltowlClass rdfID"ConsumableThing"/gt
- ltowlClass rdfID"Wine"gt
- ltrdfssubClassOf rdfresource"foodPotableLiqui
d"/gt - ltrdfslabel xmllang"en"gtwinelt/rdfslabelgt
- ltrdfslabel xmllang"fr"gtvinlt/rdfslabelgt
- ...
- lt/owlClassgt
24Tools
- Being able to express ontologies is not enoughwe
need tools! - Existing tools, especially DAMLOIL, are adapting
to OWL - Available for use in the lifetime of this group
25(No Transcript)
26Conclusions
- OWL is more expressive than RDF(S)
- OWL evolved from DAMLOIL
- There are three species of OWL
- OWL nearing completion and documents are
available - See OWL Guide for examples
- Tools are increasingly available
27Acknowledgements
- These slides are primarily based on the OWL Guide
and on a presentation by Jim Hender