Semantic Web ０６ T ０００６ YOSHIYUKI Osawa

Problem of current web  limits of search engines Most web pages are only groups of character strings. Most web pages are only groups of character strings. It is difficult for users to obtain information which they need really.

Semantic web  Web pages have meaning of the data. → meta data → meta data  The precision of the search rises.  Specific kind of information can be collected.

Meta data  Data of data  Example ・ author ・ date ・ description ・ keywords … etc.

Describe meta data  XML (eXtensible Markup Language) ・ Original tag ・ Namespace in XML

RDF (Resource Description Framework)  Method of describing meta data  Triple ・ subject (resource) ・ predicate (property) ・ object (value of property)

Example of RDF  New York has a postal abbreviation which is NY. ・ subject → urn:states:New%20York ・ predicate → ・ object → NY

Example of RDF subject predicate object

OWL (Web Ontology Language)  Definition of Network of vocabulary ・ synonym ・ antonym ・ wide sense ・ narrow sense

Example “ fast ” “ quick ” synonym recognize computer “ hot ” “ cold ” antonym

Example2 “ meat ” “ food ” “ beef ” wide sense narrow sense “ fish ”

References  an/lectures/semantic/001.pdf an/lectures/semantic/001.pdf an/lectures/semantic/001.pdf  _Description_Framework _Description_Framework _Description_Framework  003_6/06_04.html 003_6/06_04.html 003_6/06_04.html  m m m