1. 1 Technologies and Modelling Frameworks XML ontology RDF taxonomy OWL thesaurus Semantic Web

2. 2 Technologies and Modelling Frameworks Technologies: –XML –RDF –OWL Frameworks: –ontology –taxonomy –thesaurus Visionary Ideas: –Semantic Web

3. 3 Modelling Frameworks: Web Ontology A web ontology is a Web-accessible resource. It is „a machine readable set of definitions that create a taxonomy of classes and subclasses and relationships between them.“ (cf. Ontol061030.ppt) A web ontology can be used in a distributed, decentralised, information system (e.g., semantic web).

4. 4 Technologies: XML XML –eXtensible Markup Language –XML 1.0 (fourth edition) W3C Recommendation 16 August 2006, edited in place 29 September 2006: –http://www.w3.org/TR/2006/REC-xml-20060816/ XML enables "generic SGML to be served, received, and processed on the Web in the way that is now possible with HTML. XML has been designed for ease of implementation and for interoperability with both SGML and HTML.“ (cf. the link above) RDF/XML is the serialisation format for RDF. RDF/XML is also the serialisation format for OWL

5. 5 Technologies: XML XML has no formal semantics. It is not possible to know how information represented in one XML document relates to information represented in another. This allows each XML language to define its own semantics. But you cannot meaningfully merge the information content of two XML documents.

6. 6 Technologies: RDF RDF –Resource Description Framework –W3C Recommendation Feb 2004 (RDF Primer): –http://www.w3.org/TR/rdf-primer/ “RDF is to machines what HTML is to humans. –HTML allows human-understandable content to be distributed across the web and ‘hyperlinked’. –RDF allows machine-understandable content to be distributed across the web and ‘hyperlinked’.” * * Alistair Miles. “Taxonomies and the Semantic Web”, CISTRANA Workshop, February 2006

7. 7 Technologies: RDF RDF has a formal semantics Formal semantics is machine-understandable. This makes it possible to merge information from multiple sources in a consistent and meaningful way. RDF is about distributed information.

8. 8 Technologies: XML and RDF XML and RDF do different jobs. XML is about structuring text RDF is about structuring information XML Schema is a document model (a.k.a. content model) RDF Schema/OWL is an information model (a.k.a. logical model)

9. 9 Technologies: OWL OWL –Web Ontology Language. –W3C Recommendation Feb 2004: –http://www.w3.org/TR/owl-features/ OWL is about declaring and publishing web ontologies. OWL is a semantic extension of RDF, allowing you to specify additional logical dependencies between information structures. It provides additional vocabulary along with a formal semantics. OWL has three increasingly-expressive sublanguages: OWL Lite, OWL DL, and OWL Full.

10. 10 Semantic Web A semantic web is a web of machine-understandable content. Computers can analyse and merge machine-understandable content.

11. 11 Semantic Web

12. 12 Semantic Web Cf. Also:Tim Berners-Lee. Enabling Standards & Technologies - Layer Cake (http://www.w3.org/2002/Talks/04-sweb/slide12-0.html)