Semantic Web Technologies for UK HE and FE Institutions:

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Semantic Web Technologies for
UK HE and FE Institutions:

Part 2: RDF and Semantic Web Applications

Dave Beckett

dave.beckett@bristol.ac.uk


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Dave Beckett


Introduction


Dublin Core Metadata Initiative


UK JISC Services
-

mirror.ac.uk


RDN


WSE


W3C Semantic Web Activity


W3C RDF Core WG


EU IST SWAD Europe

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Outline


Introduce the ideas


The technology


Some real projects


What you can do


Open Issues

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History of the Web


In 1991 Tim Berners
-
Lee invents
the Web at CERN


However in 1989...

the original proposal

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Information Management, a Proposal, Tim Berners
-
Lee,
March 1989

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Searching the Web


Same issues in 2003


Current searches:


Which documents contain these words and
phrases?


Does not give you the information


Descriptions for humans


Must be made usable for software also

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My Data


Maintain data where it naturally is


PC revolution


PC on all desktops


Web revolution
-

everyone has web


Centralising is unsustainable


Distribution is more appropriate

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Web Architecture


Universal, scalable, evolvable


Mostly for people to interpret


URIs for identification, linking

“the web works best when any [thing] of value
and identity has a first class object”
-

Tim
Berners
-
Lee


Can link to anything

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HTML


The Web of Markup


Documents for people to read


URIs linking to other documents


Can point to anything


... even if it doesn't exist the web
doesn't break


To software, very little information

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XML


The Generic File Format


Unicode


A tree (mostly)


XML Schemas


Good for databases


Hard for humans


No linking in core XML (but Xlink)


Not webby

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The element of the Semantic
Web

Called the Resource Description Framework (RDF)

(picture by Tim Berners
-
Lee, 2003
-
01
-
28)

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Relational Database Tables

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Tables in RDF

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Trees in RDF

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(Semantic) Web Fundamentals


Everything has a URI


Resources, properties, classes


Unbounded set of terms, 404s OK


Layering is expected


A graph (web) structure


Semantic links not
<a href=”..”>text</a>


Terms can have schemas

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RDF Vocabularies (RDF Schema)


URIs for relationships and classes


Good if you re
-
use existing ones


You can make your own


Better if you re
-
use and share them


Connect them to other terms


Formalise in a vocabulary or
ontology

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CORES declaration


November 2002


GILS, ONIX, LoC/MARC, CERIF,
DOI, IEEE/LOM, DC, W3C


“... agree


To assign URIs to our elements


To articulate and publish policies regarding
the stability, persistence and maintenance of
the URIs assigned to the elements”

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RDF Family


RDF itself


RDF Schema


vocabulary
description


OWL Web Ontology Language


Lots of vocabularies


Dublin Core


FOAF


Friend of a Friend


RSS 1.0, Creative Commons, AKT, Geo, ...

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OWL


Web Ontology Language


Web
-
like linking of ontologies


Strong formal semantics


Compatibility with XML, RDF, XSD


Based on mature DAML+OIL work


Flavours


OWL, OWL DL, OWL Lite

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Case Study


Sun SwoRDFish


Sun Knowledge Services group


Create and share knowledge to solve service
issues


Many sources of data inside organisation


Many internal and external users


Business rules and access control


Want to


Enable sharing business practice, model


Add technology support for knowledge

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Case Study


Sun SwoRDFish


Open standards based


RDF, SOAP/XML, DAML+OIL


SunSolve improved


Enables more precise search


Standardises product names


Improves user experience (consistency)


Eliminates manual maintained links


Vocabulary


DC + Sun element set

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Sun SwoRDFish


Outcomes


Organisational
-
lead approach


Integrates enterprise knowledge


Data can remain distributed


Capable of flexible layering


Future opportunities for


Better RDF
-
aware searching and navigation


Richer ontology
-
aware, mining, inference
tools

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hyphen.info


AKT


Information on UK researchers


RAE data (HERO)


converted


People, Publications, Groups


An ontology in RDF, OWL


akt:Award, akt:Degree, akt:Academic
-
Degree


CS in the UK


extracted from HTML


People, Publications, Projects

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Friend of a Friend (FOAF)


People
-

who they know, what they do


Tracking provenance


who said what


FOAFNaut (SVG)


visualising


FOAF Explorer (web)


browsing


FOAFbot (IRC)


conversational


... plus can be used with anything else

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FOAFnaut view of my semantic web

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Where are the services? Portals?


Data
-
centric description so
-
far


Processing of these involves


Discovery of data, schemas, vocabularies


Query, Rules, Inference


Transferring RDF


HTTP, SOAP payloads


Web Services


however web built in REST model


Web Service Choreography


DAML
-
S, planning


Semantic Grid

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Opportunities


Sharing and syndicating descriptions


Common vocabularies between services


Richer, deeper specialised vocabularies


Less yet
-
another
-
XML
-
format


Semantics with services

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Action!


Webize your data processing tools


Adapt to an unbounded web world


Semantic web ideas and standards


Model your world, not your documents


Use RDF to transfer description


NOT: convert all your data to RDF


Although convert it if you like!

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Questions?


Thank You


dave.beckett@bristol.ac.uk

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References


Architecture of the World Wide Web, W3C
Working Draft, W3C TAG


Nodes and Arcs 1989
-
1999: WWW history and
RDF, Dan Brickley


SwoRDFish presentation, Kathy MacDougal,
Sun at W3C Tech Plenary, March 2003


Why the RDF model is different from the XML
model, Tim Berners
-
Lee