Semantics on the Web and their practical Applications

Dominique Hazaël-Massieux, W3C Team

Gira Estándares W3C 2004, Valencia

November 11 2004

Semantics on the Web?

From human readable meaning...

... to computer processable semantics

Search Engines

Google

• parses Web pages and extracts information
• relying on HTML to carry (some) semantics

HTML

• HyperText
• Markup
• Language

Language

Markup

Adds a new dimension to a text, by annotating it with semantics

Example:

<title>Semantics on the Web and their practical Applications: Markup</title>

First markup in History...

Punctuation serves to organize or clarify written language (since 200 B.C.)

and in Hieroglyphs since 2600 B.C., with cartouches

HyperText

Possibility to link two Web pages: one more dimension for the text

Concept coined by Ted Nelson in 1965

HyperTextuality is much older...

• Citations and bibliographic references
• The Bible and Talmud exegesis
  

Hypertext and Human Brains

In 1945, H. G. Wells describes a World Brain, ...a sort of mental clearing house for the mind, a depot where knowledge and ideas are received, sorted, summarized, digested, clarified and compared

Back to Search Engines

HTML powerful enough:

• to highlight specific keywords
• to evaluate a Web page through its connections to other pages

Limitations of HTML Semantics

• 91 "words" (tags)
• no qualification of links (or almost)

Semantic Web: one step further

RDF:

• allows to qualify the relationships between 2 Web Pages
• ... more generally, between 2 ideas, concepts, objects, ...
• based on Web technologies to benefit from Network effect

The Semantic Web, practically

Pratical case study: management of W3C Technical Reports

• main deliverables of W3C as a Standard Organization
• published as HTML, following well-defined rules
• managed by hand till 2002

From HTML to Semantic Web

Well defined publication rules → extracting metadata

Example: Web Architecture → resulting metadata

RDF expressive power

RDF used to describe:

• an invidual document
• the rules a document obeys to (OWL illustration)
• the publication process (Rules illustration)

Powerful combinations

• RDF & HTML: TR page and its various views (by editor)
• RDF & SVG
• XSLT and XML (e.g. Internationalization)

Decentralized work

• Web development based on decentralization
• allows each team to express its own expertise
• ... and to benefit from others'

More about HTML and Semantics

RDF is a model more than a format

• on-going efforts to add more semantics to HTML
• XHTML 2 and GRDDL

A Quick GRDDL Demo

Semantic Web vision

• allows data as well as documents
• integration format for any type of data: calendars, personal information, photos description, news feed, genes, airplanes parts
• integrated with other Web technologies (network effect)

Thank you for your attention

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