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Semantic Web Technologies
for UK HE and FE Institutions:
Part 1: Background to the Development of the Web
Brian Kelly
UK Web Focus
UKOLN
[email protected]
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Background
Brief History of the Web:
1991
1993
1995
Tim Berners-Lee invents Web at CERN.
Web consists of three architectural
components: data format (HTML), addressing
(URIs) and transport (HTTP)
Early adopters in UK HE begin evangelising (to
an initially sceptic audience)
Web seen as the killer app in UK HE (farewell
to Gopher, home-grown info systems, …)
Who can remember the excitement caused when the Web first appeared?
"You mean I just have to click here and this Virtual Frog appears from the
US? It's magic"
Also notice the short time it took to become mainstream.
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The Web Grows Up
The Web:
 Initially simple to understand and easy to deploy
 Limited in functionality, expensive to maintain, …
So we see rapid developments in core architecture:
• CSS: simple separation of structure and content. You
must be using CSS – no argument, just some
implementation issues.
• XML: the killer meta-language for creating languages.
XML must be the key format for your IT strategy – no
argument, just some implementation issues.
• SVG, SMIL, MathML: examples of 'cool' formats being
developed in W3C, with many other formats being
developed elsewhere (e.g. OASIS)
• XHTML 2.0: Will allow us to escape from the mess
caused by non-compliant HTML/XHTML 1.0
documents (XHTML 2.0 must be compliant)
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More On XML
XML is more than just a meta-format for
creating other formats:
• XSLT: Enables XML resources to be converted to
other formats (other XML languages or other
formats such as PDF)
• XLink, XPointer, ...: Address the limitations of the
hypertext model in the initial Web (e.g. embed
link into existing document; link to the 2nd-4th
bullet point; …)
• XML Schemas: Define structure and constraints
of XML documents
• XML Namespaces: Allow XML documents to be
merged without problems caused by name
clashes (e.g. < title > of document,
<title> of person, <title> of book, …)
• …
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More The Just Documents
XML:
• Can be used to define protocols (rules) and not
just document formats
• Is at the heart of "Web Services" – a Web-based
infrastructure for allowing computers to
communicate with computers in a rich way
Key aspects to Web Services:
• SOAP: An XML-based protocol for
communications between computers
• WSDL: An XML-based description of a Web
Service
• UDDI: A mechanism for finding Web Services
• …
Web Services is about connecting computers
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But XML Isn't Enough …
But XML still has its limitations:
An XML record
<catalogue>
<author>George Orwell</author>
<title>1984</title>
…
</ catalogue>
An XML record
<catalogue>
<le-creator>George Orwell</le-creator>
<le-title>1984</le-title>
…
</ catalogue>
How will an automated tool know that these records
(and ones in other languages) are similar?
Coding transformations into the automated tool is not
a scalable solution
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RDF – XML To The Rescue!
The solution to this problem is:
•
•
•
•
To use an XML
To embed some form of magic into the XML tags
The XML application is called RDF
RDF is at the heart of the Semantic Web
Encoding magic Into an XML record
<catalogue>
<rdf magic>George Orwell</rdf>
<rdf magic>1984</rdf>
…
</ catalogue>
The magic isn't, in fact,
magic, but a simple
mathematical expression
which enables data to be
integrated with data from
other sources together
with use of URIs.
The Semantic Web is about connecting data
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Semantic Web Technologies
for UK HE and FE Institutions
After several years of discussion about the Semantic
Web and RDF much architectural work has been done
and we are now beginning to see interesting Semantic
Web applications.
So let's now hear about:
• How RDF actually works
• How RDF and the Semantic Web relate
• The potential for Semantic Web technologies in
UK HE and FE institutions
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