W3C - The World Wide Web Consortium

Members: Companies or Organizations (currently around 290), full or affiliate
Hosts: MIT LCS (Cambridge, MA, USA), INRIA (France), Keio University
Team: Technical and support staff (50)
Technical Work: Working Groups, Interest Groups, Coordination Groups
Documents: Working Drafts, Proposed Recommendation, Recommendation; Notes

W3C Domains and Activities

User Interface Domain: HTML, CSS, XSL, DOM, MathML, SVG, I18N, Mobile, Amaya
Architecture Domain: HTTP, HTTP-NG, XML, Web Characterization, SMIL, TV and Web, Jigsaw, libwww
Technology and Society Domain: RDF, PICS, P3P, Security, Digital Signatures, Policy, Electronic Commerce
Web Accessibility Initiative: Reviews and Recommendations
W3C home page (http://www.w3.org/)

W3C Membership Benefits

Information : Web site, Workshops
Image : Public relations (e.g. Press)
Involvement : Strategy, Working Groups
Influence : Submissions, Visiting Engineers

Web Architecture: XML, RDF, and P3P

HTML, MathML and many other applications are based on XML

Other components: HTTP, DOM,...

XML Basics

Started out as "SGML for the Web"
Drastic simplification of SGML
Use for Documents and Data
Create your own tags and tag sets
Internationalization built in from the start
W3C Recommendation (http://www.w3.org/TR/REC-xml, February 1998)

XML: A Simple Example

<customer-details id="AcPharm39156">
    <name>Acme Pharmaceuticals Co.</name>
    <address country="US">
        <street>7301 Smokey Boulevard</street>
        <city>Smallville</city>
        <state>Indiana</state>
        <postal>94571</postal>
    </address>
</customer-details>

XML: Namespaces

Avoid name clashes
Associate element and attribute names with URIs
Important for RDF
Currently a Proposed Recommendation (http://www.w3.org/TR/1998/PR-xml-names)

XML: Current Activities

XML Activity Statement (http://www.w3.org/XML/Activity.html)

Work split up into five working groups:

XML Schema WG
XML Linking WG
XML Information Set WG
XML Fragment WG
XML Syntax WG

RDF Basics

At the start: common base for metadata on the WWW
Basic knowledge representation (KR)
Three representations: graph, tuples, XML
RDF Model and Syntax Working Draft (http://www.w3.org/TR/WD-rdf-syntax/)
RDF Schema Working Draft (http://www.w3.org/TR/WD-rdf-schema/)

RDF Model

Tuples: (predicate, subject, object)
Facts about (subject) WWW resources and other things
"Data types":
- Resources: Identified by URI
- Literals: Text strings including XML markup
- Properties: Subset of Resources
- Types: Subset of Resources
Reification for statements about statements

RDF Example

Example in natural language: The creator of http://www.w3.org/Home/Lassila is "Ora Lassila".

Example as a graph:
Simple node and arc

Example in simplified XML:

  <rdf:RDF>
    <rdf:Description about="http://www.w3.org/Home/Lassila">
      <s:Creator>Ora Lassila</s:Creator>
    </rdf:Description>
  </rdf:RDF>

Example in full XML:

  <?xml version="1.0"?>
  <rdf:RDF
    xmlns:rdf="http://www.w3.org/TR/WD-rdf-syntax#"
    xmlns:s="http://description.org/schema/">
    <rdf:Description about="http://www.w3.org/Home/Lassila">
      <s:Creator>Ora Lassila</s:Creator>
    </rdf:Description>
  </rdf:RDF>

Example in tuple notation:

(http://description.org/schema/Creator, http://www.w3.org/Home/Lassila, "Ora Lassila")