SWAD-Europe newsletter, March 2004

SWAD-Europe Newsletter, March 2004

Welcome to the third SWAD-Europe newsletter.

SWAD-Europe (Semantic Web Advanced Development in Europe) is an
EU-funded project which aims to support W3C's Semantic Web initiative
in Europe, providing targeted research, demonstrations and outreach to
ensure Semantic Web technologies move into the mainstream of networked
computing.
http://www.w3.org/2001/sw/Europe/

This newsletter is a monthly summary of work from the project and
selected Frequently Asked Questions and answers, written by a variety of
project participants.

In this issue:

News
1. Semantic Blogging update
2. Announcing SKOS-Core 1.0 RDF Schema for Thesauri
3. MathML Use Case

FAQs
4. How do I parse RDF?
5. Using RDFS or OWL as a schema language for validating RDF

More detailed discussions on these topics are available on the project
weblog:
http://esw.w3.org/mt/esw/archives/2004_03.html
http://esw.w3.org/mt/esw/


News

1. Semantic Blogging update

It's been an interesting month for semantic blogging. I'm in the midst
of writing papers and articles, some external, some internal. We're
also trying to deploy semantic blogging internally, a true 'eat your
own dogfood' approach. I'm hoping to demonstrate an early prototype at
XMLEurope 2004 in Amsterdam. If you can't make it, then the paper is
available from my site. --Steve Cayzer

Steve's site:
http://jena.hpl.hp.com:3030/blojsom-hp/blog/news/swade/?permalink=57D7C0D36251821004C68A891D2904BF.textile&smm=y

SWAD-Europe workpackage 12.1 - Open Demonstrators:
http://www.w3.org/2001/sw/Europe/plan/workpackages/live/esw-wp-12.1.html

SWAD-Europe  Deliverable 12.1.2: Semantic Blogging and Bibliographies -
Requirements Specification
http://www.w3.org/2001/sw/Europe/reports/requirements-demo-1/hp-requirements-specification.html


2. Announcing SKOS-Core 1.0 RDF Schema for Thesauri

SKOS stands for Simple Knowledge Organisation System. The Goal of
SKOS-Core is to provide a framework for bringing existing knowledge
organisation systems such as thesauri and the semantic web together.

SKOS-Core exploits the features of RDFS and OWL to provide a flexible
and extensible framework within which different types of KOS can
interoperate. SKOS-Core is ideal for modelling thesauri, and can cope
with the variations commonly found in thesaurus design and structure.
--Alistair Miles

Read more:

SKOS-Core 1.0 schema:
http://www.w3.org/2004/02/skos/core

SKOS-Core 1.0 Guide accompanying the schema:
http://www.w3.org/2001/sw/Europe/reports/thes/1.0/guide/

The website for the SWAD-Europe Thesaurus Activity has moved to
http://www.w3.org/2001/sw/Europe/reports/thes/

SWAD-Europe workpackage 8 - Thesaurus Research Prototype:
http://www.w3.org/2001/sw/Europe/plan/workpackages/live/esw-wp-8.html


3. MathML Use Case

For the RDF, Web Ontology, Logic and Mathematics part of SWAD-Europe
workpackage 5, I have written an XSLT transform that evaluates MathML
equations on "CompanyReport" files, as provided by Dan Brickley. The
stylesheet works on a Content MathML file (e.g. mmlrules.xsl)
containing computation rules, such as rna = opoa*na/100:

  <apply>
    <eq/>
    <ci>rna</ci>
    <apply>
      <times/>
      <apply><divide/><ci>opoa</ci><ci>na</ci></apply>
      <cn>100</cn>
    </apply>
  </apply>

The stylesheet retrieves a file (e.g. reports.xml) containing the values
of the variables and computes the appropriate results and prints them to
standard output: atr = 1.72139269716302 ca = 52798 etc. Currently the
stylesheet only supports +-/*. While it's easy to add more template to
support more of MathML, it's less easy to actually perform complex
operations. However using exslt might allow coverage of many ops.
--Max Froumentin

Read More:

XSLT stylesheet:
http://www.w3.org/2004/03/swadeu-mathml/mml.xsl

Content MathML file
http://www.w3.org/2004/03/swadeu-mathml/mmlrules.mml

Sample XML file:
http://www.w3.org/2004/03/swadeu-mathml/reports.xml

Workpackage 5 description:
http://www.w3.org/2001/sw/Europe/plan/workpackages/live/esw-wp-5.html

Deliverable 5.1: Schema Technology Survey
http://www.w3.org/2001/sw/Europe/reports/xml_schema_tools_techniques_report/

Deliverable 5.2 Extracting Semantics from XML Structure
http://www.w3.org/2001/sw/Europe/reports/xslt_schematron_tool/

Deliverable 5.3 RDF/XML Test cases for RDF Logic, Web Ontology and Maths
content
http://www.w3.org/2001/sw/Europe/reports/xml_test_cases/



FAQs

4. How do I parse RDF?

Application developers often ask how they can get RDF data from
the semantic web into their application from the recommended syntax
RDF/XML. This usually ends up being a question about parsing syntaxes
and APIs in certain languages. There are widely available, mature and
standards-compliant open source parsing libraries available for most
high level programming libraries that application developers might need.
This article provides a summary of good and up-to-date choices.
--Dave Beckett

Read more:
http://esw.w3.org/mt/esw/archives/000049.html


5. Using RDFS or OWL as a schema language for validating RDF

Many software applications need the ability to test that some input data
is complete and correct enough to be processed, e.g. to check the data
once so that access functions will not later on break due to missing
items. This is commonly done by using a schema language to define what
"complete and correct" means in this, syntactic, sense and a schema
processor to validate data against the schema.

Developers new to RDF can easily mistake RDFS as being a schema language
(perhaps because the 'S' stands for schema!), they then get referred to
OWL as providing the solution and then get surprised by the results of
trying to use OWL this way.

This is a big topic which we'll just touch on here. In this FAQ entry I
just want to illustrate a few of pitfalls and hint at why this is harder
than it looks in the hope that it might reduce the "unpleasant surprise"
for developers new to OWL. --Dave Reynolds

Read more:
http://esw.w3.org/mt/esw/archives/000048.html



Visit the SWAD-Europe website:
http://www.w3.org/2001/sw/Europe/
http://www.w3.org/2001/sw/Europe/reports/intro.html

and weblog:
http://esw.w3.org/mt/esw/

for ongoing information about the project.

Received on Monday, 5 April 2004 08:29:14 UTC