[>>]	..semantic web

is an extension of the current web in which information is given well-defined meaning, better enabling computers and people to work in cooperation.
--
Tim Bernes-Lee, James Hendler, Ora Lassila [BHL2001]

[<<] [>>]

..deals with

• Knowledge Representation
• Ontologies
• Automated Reasonnig
• Data Mining
• Artifical Intelligence

[<<] [>>]

..will introduce

• searching engines that give more exact answers
• intelligent user agets that can automate many tasks, e.g. information exchange for their user

[<<] [>>]

..rdf

Resource Description Framework

• general purpose language for representing information in the World Wide Web
• intended to represent metadata about web resources
• can represent information about anything

[<<] [>>]

..data exchange

• framework for expressing information in way that it can be exchanged between applications without loss of meaning
• information may be available to other applications than those for wich it was originally created.

[<<] [>>]

..specification

• RDF Model and Syntax
• RDF Model Theory
• RDF/XML Syntax
• RDF Schema
• RDF Test Cases
• RDF Primer
• even more, see RDF homepage

[<<] [>>]

..scope

• what information can RDF represent?
• what does RDF look like?
• how is RDF information created, accessed and processed?
• what are the known RDF applications?

[<<] [>>]

..basics

• making statements about resources
• assertions: subject, property, object

The creator of tbc's homepage is Martin Homola.

[<<] [>>]

..requirements

• to make assertions machine readable we need
• • system of unique machine processable identifiers
  • machine processable format for representing these statements and exchanging them between machines

[<<] [>>]

..we have them

• URIs
  Unified Resource Identifiers
• XML
  eXtensible Markup Language
• Literals

[<<] [>>]

..xml and meaning

I just bought a new dog.

[<<] [>>]

..xml and meaning

I just bought a new dog.

<sentence> <person>I</person> just bought a new <animal>dog</animal>. </sentence>

[<<] [>>]

..xml and meaning

I just bought a new dog.

<sentence> <person>I</person> just bought a new <animal>dog</animal>. </sentence>

<mngrof> <ungha>I</ungha> just bought a new <mongha>dog</mongha>. </mnrgrof>

[<<] [>>]

..rdf model

• subject, property are resources
• object is resource or literal
• resources are identified by URIs

subject has a property which value is object

http://tbc.sk/ has a http://purl.org/dc/elements/1.1/creator property which value is Martin Homola

[<<] [>>]

..3 ways

• N-Triples
• graph
• XML

[<<] [>>]

..N-Triple

<http://tbc.sk/>
<http://purl.org/dc/elements/1.1/creator>
"Martin Homola" .

[<<] [>>]

..graph

[<<] [>>]

..xml again

<?xml version="1.0"?> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.1/"> <rdf:Description rdf:about="http://tbc.sk/"> <dc:creator>Martin Homola</dc:creator> </rdf:Description> </rdf:RDF>

[<<] [>>]

..new resources

<?xml version="1.0"?> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.1/"> xmlns:person="http://tbc.sk/RDF/person.rdf/"> <rdf:Description rdf:about="http://tbc.sk/"> <dc:creator>#tbc</dc:creator> </rdf:Description> <rdf:Description rdf:ID="#tbc"> <person:realname>Martin Homola</person:realname> <person:nickname>tbc</person:nickname> <person:homepage rdf:resource="http://tbc.sk/"/> </rdf:Description> </rdf:RDF>

[<<] [top]

..references

• [BHL2001] Tim Bernes Lee, James Hendler, Ora Lassila: The Semantic Web, Scientific American, May 2001