Seeds of the Semantic Web

Dan Connolly, W3C

ALA Midwinter Meeting 2000
January 2000, San Antonio, TX

Overview

• Where we are: on the verge of another revolution
• Where we came from: history and motivation
• Where we're going: opportunities and challenges

The Revolutions

• The HTML Revolution: shared information space
• The XML Revolution: culture of open exchange
• The RDF Revolution: rise of the Semantic Web

The HTML Revolution: Hypertext Goes Global

• 1945: Bush imagines the ultimate research tool
• 1970s: NLS, KMS, ... amazing research prototypes failed to 'cross the chasm' of deployment
• 1990: TimBL develops a minimal hypertext system for the Internet
  • Web explodes out of a critical mass of content, connectivity
  • No more need to "imagine a world of connected information..."

The XML Revolution: Plans

Shared costs:

• Development, Debugging
  • no "bit tweezers"; helps the "desperate perl hacker"
  • Structured Text: the critical features of SGML at a fraction of the cost
  • Internationalized text
• Education, Training
• Basis for higher-level agreements

The XML Revolution: Plans (cont.)

XML is the ASCII of the future.

--Tim Bray
XML Files, Oct 1998

XML is a simple data format that balances the needs of people to read/write data with needs of machine to read/write data.

The XML Revolution: Hopes

I want my data back.

--Jon Bosak

• Self describing: DTDs, Schemas, Namespaces
• Decentralize from HTML to community markup
• Culture of Open Exchange

Stepping Back...

Origin and Goals of the Web

1. Human communication thru shared knowledge
   Working together: Social efficiency, understanding and scaling
2. Exploitation of computing power in real life

Why W3C?

Leading the Web to its Full Potential

• Foster Evolution
• Preserve Interoperability

About W3C

• Founded Fall '94
• 350+ Members
• Director, staff
• One International Consortium, 3 Hosts:
  • MIT in Cambridge, MA
  • INRIA in Sophia-Antipolis, France
  • Keio in Tokyo, Japan

W3C Activities: What We Do

• User Interface Domain
  HTML, Stylesheets, Internationalization, ...
• Technology and Society
  PICS, Metadata, Security, E-Commerce, ...
• Architecture
  HTTP, HTTP-NG, XML, SMIL, ...
• Web Accessability Initiative (WAI) Guidelines, Outreach, Technical review, ...

W3C Process: How We Work

• Advisory Committee
• Working Groups
• Specification Development:
  Note, Working Draft, Proposed Recommendation, Recommendation
• Submissions
• Workshops, Symposia

See also: W3C Process

Looking Ahead...

XML in a Nutshell

XML balances the needs of people to read/write data with needs of machine to read/write data.

<elementName attributeName="value">
 <empty />
</elementName>

Stupid Data

<product>
 <description>Blue Widget</description>
 <price>1.25</price>
 <size>4</size>
</product>

What's wrong with this picture?

Why Stupid Data Hurts

• Price: 1.25 what? Dollars? Pesos?
  similarly for size
• Unclear relation to commerce, contracts and law:
  • obligation to honor that price? for how long?
  • liability for accuracy of description?

Grounding Terms in the Web

<product
   xmlns:w="http://www.acme.com/2000/specs"
   xmlns="http://www.ali.org/1992/commercial-code"> <!--*-->
 <description>Blue Widget</description>
 <price currency="USD">1.25</price>
 <w:size>4</w:size>
</product>

* The American Law Institute hasn't published the Uniform Commercial Code on the web, but the Cornell Legal Information Institute published a hypertext version.

Stupid Database Exchange: Travel

• Airline sends me email from their database
• I copy/paste each of the data into my PDA

What's wrong with this picture?

Really Smart Data: RDF

<color>blue</color>

<specific-gravity>4.5</specific-gravity>

you know what that means... sort of.

RDF: Knowledge Primitives

<substance>
  <atomic-number>54</atomic-number>
  <specific-gravity>4.5</specific-gravity>
</substance>

• Some resource is of type substance.
• That resource has atomic-number 54.
• That resource has specific gravity 4.5.
• A substance has atomic number 54, and has specific gravity 4.5.

RDF: Graph Merging

<PDA:event>
  <dc:coverage>2000-01-15</dc:coverage>
  <pda:import href="http://movies.yahoo.com/showtimes?show=23ou209"/>
</PDA:event>

<movie about="http://movies.yahoo.com/showtimes?show=23ou209">
 <dc:coverage>2000-01-15T2300Z</dc:coverage>
 <dc:title>Life is Beautiful</dc:title>
 <ucc:price currency="USD">7.50</ucc:price>
</movie>

Knowledge of Communities Large and Small

I want my machine to understand about...

• Internet Standards
• International trade agreements
• Credit Card agreements
• Local cinema schedules
• Little league schedules
• my plans for the day

notes