Embedding OWL-RDFS syntax in XHTML with RDFa
David Decraene is looking for feedback on his article Embedding OWL-RDFS syntax in XHTML with RDFa, which is a “Short introduction to RDFa, OWL and Microformats”, and aims to come up with:
a solution that reconciles the ease of use of Microformats with the expressivity of a language like OWL. Some problems hindering OWL adoptation will be highlighted, and a first experiment with the use of RDFa mark-up to embed OWL data directly into an XHTML page will be demonstrated, a solution that can be considered as a step higher than Microformats on the evolutionary ladder of the web.
He argues that OWL has a poor presence on the web, attributing this mainly to the fact that no-one has explored approaches to “align / integrate OWL with current web content”:
For ontological data to truly be useful, you need to somehow tie current web content with semantic classes and instances. OWL has failed miserably in this respect so far. It is much like a far away island of Eden, and a man without a canoe. All the important data could be there but no-one knows how to reach it. Granted, OWL does define a standard format for data interchange between applications, but this limited scope cannot be what the semantic vision is about.
Interestingly enough, if you replaced the word ‘OWL’ with the word ‘RDF’, you’d have pretty much the main motivations that spurred the development of RDFa in the first place. David goes on to give an example:
What we need is semantic annotation. You need to be able to tag sections of your content with explicit ontology classes and even relations, without it hindering the display of your content. If you wrote a piece on a certain bordeaux for example, you could mark up the section as being about an instance of wine, perhaps even with some properties defined (or even more amazing, just by knowing it is about wine properties can be extracted automatically, a mention of red is bound to be about the wine color).
Whilst there is no doubt that the kind of complex RDFa David uses in his post is not for the everyday user of RDFa, the fact that RDFa can be used for these kinds of complex examples shows that the architecture is solid.
(This rdfa.info post also appears on XForms and Internet Applications.)
December 2nd, 2007 at 5:53 pm
Forgive me, but this seems somewhat confused to me - seems like it would be better to define the OWL in another file, and have the markup that includes OWL be used to create instances - which makes it just using RDFa to do RDF which is a relatively clean process. One could then include an imports statement or a seeAlso (I admit getting the instance data and the ontology read in at the same time is still a bit of a black art) - but defining a restriction within the RDFa seems to me to be doing a lot of extra work for little gain. I’m a big fan of RDFa (and GRDDL) and some OWL for that matter, but OWL was defined based on URIs in part to make it easy to define the classes and properties in one place and use them in another - which seems to me what David is trying to do.
(Note that I would have left direct feedback there, but to do so would have meant joining yet another googlegroup, where I’m already drowning in email…
-J Hendler