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<?xml version="1.0" encoding="iso-8859-1"?>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>The Semantic Web</title>
<link rel="stylesheet" type="text/css" title="W3C Talk"
href="../../../Tools/w3ctalk-summary.css" />
<link href="em.css" rel="stylesheet" type="text/css" />
</head>
<body xml:lang="en" lang="en">
<h1>The Semantic Web</h1>
<p align="center"><a href="http://http://www.w3.org/People/Berners-Lee/">Tim
Berners-Lee, Director</a>, Director<br />
</p>
<p align="center">W3C World Wide Web Consortium</p>
<p>Academic discussion,</p>
<p>Japan Prize 2002</p>
<p><br />
<br />
</p>
<p>Slides available at:<br />
<a
href="http://www.w3.org/Talks/2002/Talks/04-sweb/slide1-1.html">http://www.w3.org/2002/Talks/04-sweb/</a><a></a></p>
<h1>The Semantic Web</h1>
<ul>
<li>Context: World Wide Web Consortium</li>
<li>History: World Wide Web</li>
<li>Levels of expressiveness</li>
</ul>
<h1>Context: World Wide Web Consortium</h1>
<ul>
<li>Formed 1994</li>
<li>50 member companies/organizations</li>
<li>Host sites: MIT, INRIA, Keio</li>
<li>Semantic Web is 1 activity of many</li>
<li><a href="http://www.w3.org/">www.w3.org</a></li>
</ul>
<h1>History: The Web Idea</h1>
<p style="text-align: center"><img src="../04-sweb/Architecture.crop.gif" alt="Pre web"
/></p>
<h1>The Current Web</h1>
<table>
<tbody>
<tr>
<td valign="top"><p class="figure" style="text-align: center"><object
width="342" height="454" type="image/svg+xml" name="web"
data="../04-sweb/web.svg">
</object>
</p>
<span class="source">Machine cannot understand the meaning of the
links.</span>
<p><span class="source">[alternate <a href="web.png">png</a>, <a
href="web.gif">gif</a> images]</span></p>
</td>
</tr>
</tbody>
</table>
<p></p>
<h1>The Semantic Web: The original web realized</h1>
<p>Information Management: A Proposal, Tim Berners-Lee, CERN, March 1989, May
1990, <a
href="http://www.w3.org/History/1989/proposal.html">http://www.w3.org/History/1989/proposal.html</a></p>
<p class="figure"><img alt="image of timbl original web proposal"
src="timbl-1989-image.gif" /></p>
<h1>The Semantic Web - A Simple Extension to the Current Web</h1>
<table>
<tbody>
<tr>
<td valign="top"><p class="figure"><object width="432" height="454"
type="image/svg+xml" name="web" data="../04-sweb/sweb.svg">
</object>
</p>
</td>
</tr>
</tbody>
</table>
<p>Binary relationships capture the meaning of the link</p>
<h1>Goal: building machinery</h1>
<table border="0">
<tbody>
<tr>
<td width="70%"><cite>"The bane of my existence is doing things that I
know the computer could do for me."</cite>
<p>-- Dan Connolly, The XML Revolution</p>
</td>
<td align="right"><p><img alt="computer refuses to do tasks"
src="bane.png" /></p>
</td>
</tr>
</tbody>
</table>
<h1>SW Principles</h1>
<table>
<tbody>
<tr>
<td><ul>
<li>Any abstract thing can have a URI#xxx.</li>
<li>Vocabularies can merge and be replaced with time</li>
<li>"Anyone can say anything about anything"</li>
<li>No one system knows everything</li>
<li>Design must be minimalist</li>
</ul>
</td>
</tr>
</tbody>
</table>
<h1>Expressive power</h1>
<p class="figure"><img alt="architectural layers" src="sw-stack-2002.png"
/></p>
<h1>RDF layer: Entities and Relations</h1>
<p><img src="../04-sweb/arcs-1.gif" alt="a set of circles and arrows" /></p>
<h1>...superimpose</h1>
<p><img src="../04-sweb/arcs-3.gif" alt="more circles and arrows superim" /></p>
<h1>RDF: Semantic links - "Joining the Web"</h1>
<p style="text-align: center"><img src="../04-sweb/zipcode.png"
alt=" Links between column headings " /></p>
<h1>RDF: Application Integration Hub</h1>
<ul>
<li>Consider an enterprise with N applications</li>
<li>Using XML:
<ul>
<li>N*N scripts in XSLT to integrate</li>
</ul>
</li>
<li>Using RDF:
<ul>
<li>N conversions to hub vocabulary</li>
<li>Higher level of initial understanding</li>
</ul>
</li>
</ul>
<h1>RDF Schema layer</h1>
<ul>
<li>Minimalist model - (thing), Class, Property</li>
<li>Subproperty, Subclass</li>
<li>Domain & Range</li>
<li>Comments & labels</li>
<li>Very wide interoperability</li>
</ul>
<p>All that is needed for interoperability of the vast amount of "data" on
the web.</p>
<h1>Ontology layer</h1>
<ul>
<li>More metainformation, such as
<ul>
<li>Transitive property</li>
<li>Unique, Unambiguous, Cardinality, etc</li>
</ul>
</li>
<li>Ontology community exists- DL, OIL, SHOE, etc. etc.</li>
<li>Huge extra usage for extra functionality</li>
<li>Not Turing complete, tractable.</li>
</ul>
<p>Wide interoperability & interconversion</p>
<h1>Rules Layer</h1>
<ul>
<li>General purpose rules languages that allow query and filtering</li>
<li>Query similar to SQL</li>
<li>Many rules systems currently exist</li>
<li>Rules layer allows form of Proof without full Logic layer</li>
</ul>
<h1>Logic layer</h1>
<ul>
<li>Universal language for monotonic logic</li>
<li>Any rule system can export, generally cannot import</li>
<li>No one standard engine - inference capabilities differ</li>
<li>Many engines exist (SQL to KIF, Cycl, etc)</li>
<li>Any system can <em>validate</em> proofs</li>
<li>Web assumptions different from closed world</li>
</ul>
<h1>Web of Trust</h1>
<ul>
<li>All statements on the Web occur in some context.</li>
<li>Applications need this context in order to evaluate the trustworthiness
of the statements.</li>
<li>The machinery of the SW does not assert that all statements found on
the Web are "true".</li>
<li>Trustworthiness is evaluated by each application.</li>
<li>Very flexible language can express existing systems</li>
</ul>
<h1>Web of Trust - simplified example</h1>
<p><img alt="example of trust processing" src="elisaaccess.png" /></p>
<h1>Semantic Web bus - and above</h1>
<p style="text-align: center"><img src="../04-sweb/sweb-bus.gif"
alt="Data interworking feeds logic b" /></p>
<h1>Conclusion</h1>
<p>Too general to be aimed at any specific application</p>
<ul>
<li>A web of information machines can help us with</li>
<li>Catalogs on the web?</li>
<li>Electronic commerce transactions</li>
<li>Operating across many apps (eg PDAs)</li>
<li>Your favorite ....</li>
</ul>
<h1>More information</h1>
<ul>
<li>Semantic Web Home Page: <a
href="http://www.w3.org/2001/sw/">http://www.w3.org/2001/sw/</a></li>
<li>Semantic Web Advanced Development Home Page: <a
href="http://www.w3.org/2001/sw/">http://www.w3.org/2000/01/sw/</a></li>
<li>RDF Home Page: <a
href="http://www.w3.org/rdf/">http://www.w3.org/rdf/</a></li>
<li>Semantic Web / RDF Interest Group: <a
href="http://www.w3.org/RDF/Interest">http://www.w3.org/RDF/Interest</a></li>
<li>Semantic Web / RDF IRC: <a
href="http://www.w3.org/RDF/Interest/#irc">irc://openprojects.net/#rdfig</a></li>
</ul>
<p></p>
<p>ends</p>
<p></p>
</body>
</html>