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- Dec 9, 2008
OntoWiki Workshop
Days 3 and 4 of the OntoWiki KickOff Meeting in Leipzig were comprised of semantic technologies and OntoWiki development workshops.
Just like the overall organization of the project meeting was very good, so Sebastian Dietzold, Sebastian Hellmann, Michael Martin and Jörg Unbehauen did a real good job at putting the ideas behind key concepts of the semantic web across in several introductory SemWeb presentations. Their talks about various technologies from the semantic web stack like URIs, RDF and its serialisations, RDFS, SPARQL and some related tools were well suited to bring people who are relatively new to the semantic web up to speed. Links to the presentation slides can be found at the project page in the coming days.
Later Jens Lehmann outlined the new things OWL 2 brings, e. g. profiles, which are subsets of OWL 2 and which provide different degrees of expressivity and reasoning efficiency.
The last day started with Sören Auer’s presentation of their semantic wiki OpenResearch, a site where information on conferences, journals and scientists is pooled. OpenResearch is built with Semantic MediaWiki (SMW), just like our Social Semantic Web wiki.
While SMW is a very useful tool as it lowers the entry barriers for using semantic wikis, Sören also pointed out that in comparison OntoWiki provides some important features that SMW doesn’t have:
- SMW doesn’t use SPARQL for its queries, but a less powerful custom query language, whereas OntoWiki has full SPARQL support.
- OntoWiki’s UI has many widgets that support the user when entering data or new properties on a page (e. g. there is an autocomplete feature for suggesting properties)
- With SMW changes to the wiki’s semantic structure often entail manual changes to many, many pages. With OntoWiki it is easy to e.g. change poperties at any time.
For the new version of OntoWiki Sören and his team use the Zend framework and develop the Erfurt API to store and access RDF data. The Erfurt API supports SPARQL, versioning, caching and RDF based authentification/access control. It abstracts different stores using the adapter pattern, so it can be used with Virtuoso and any other store which has an interface provided by Zend_Db (MySQL, Oracle, PostgreSQL, etc.) plus they are working on an interface for Redland. Find the slides for Philipp Frischmuth’s Erfurt API presentation here, the API documentation here and Norman Heino’s Zend & OntoWiki Application Framework presentation here.
Julian Jöris demonstrated how Selenium is used for acceptance testing. This is a very promising testing framework for web applications, where one can e.g. record interactions with different browsers and automatically run them as tests. Selenium has a Firefox extension to record macros and is integrated with PHPUnit.
Finally we had a very good discussion about our conX–OntoWiki integration use case and application ideas, so we left Leipzig with a pleasant anticipation of the coming co-operation in the project.