User ivan - Semantic Overflow

Answer by Ivan for Which tools offer support for OWL2?

2010-03-23T20:18:49Z

http://tinyurl.com/ydmr2tt gives you an overview of OWL tools but, unfortunately, there is no separate search facet of OWL2 vs OWL. But it may be a good first start. http://www.w3.org/2001/sw/wiki/OWL might give you more pointers

Answer by Ivan for Are there such things as RDF editors?

2010-02-17T13:45:08Z

It is not free (well, fairly pricy, in fact) but I had some good experiences with Altova's Suite, if you are o.k. using RDF/XML (and not Turtle). There is also a visual editor for (simple) vocabulary editing, too. It is, in fact, an xml editor (which helps a lot already in filtering out some of the common problems) but knows about the basics of RDF/XML.

I must admit that an average XML editor (in emacs, jEdit, or elsewhere) does help a lot by itself.

Answer by Ivan for Both @rel and @rev on one element in RDFa

2010-02-17T13:41:28Z

The answer is: yes, it is allowed. I agree that it is not widely used but, in a way, it would be more convoluted (spec-wise) to disallow it than to allow it!

Answer by Ivan for Simple CLI useable OWL Reasoner

2009-11-11T07:44:09Z

Jerven,

to be able to answer your question (well, attempting to do so) I should understand it in details which I don't:-( I am not sure what 'core owl' means, for example. But I will try anyway, in the hope that this will be helpful...

There are different aspects that I can try to reflect on...

proper OWL engines will give you an answer two out of the three issues, namely finding the 'contradictions' (ie, whether there is consistency error) and showing which triples are inferred. There are several sites that list implementations; the implementation report of the OWL Working group is probably one of the most recent. Note that, afaik, some of the editors in the list will also detect inconsistencies, or at least some of them, so it is worth looking at those. (I am not a user of Pellet, but I must admit I did not understand your answer to that proposal. Merging two RDF files into one is really not a difficult issue, if this is the only problem you have with Pellet...)

I could not look at the details of your ontology, it is fairly large, but you might want to see whether it fits one of the OWL 2 profiles. If so, there might be some simpler tools around. Eg, if it falls under the OWL 2 RL category, then simpler rule engine based implementation may also work. (I do not know whether there is already a Jena based implementation available, but if not, it is only a question of time.

you also asked "explaining which rules are the source of the contradiction and/or inference". That is much more of an R&D question, I am afraid. The best paper award for the ISWC2008 conference, for example, touched exactly on that aspect; current tools still have to evolve in this area...

As I said, I hope this helps...

Ivan

Answer by Ivan for What is the perfect programming language for semantic web development?

2009-11-09T08:33:42Z

First of all, I would like to understand why... I am afraid that pushing OWL or RDF into an Object Oriented framework may give a false impression to users that can lead to conceptual errors.

Dynamic typing is not the only issue that separate these two worlds. Take, for example, the ':p rdf:range :q' in RDFS. Many people make the error that this means some sort of a 'constraint' on :p, and that is often because they make the connection to traditional programming environments (loosely with the type of a function's return value). But, in RDFS, this statement is a license to infer, which is quite different.

All that being said: there was a time when delegation based languages were in vogue. I would certainly look in this direction rather than OO languages... Though I have never really given thoughts to that, I must admit...

Answer by Ivan for Which Tools and Libraries do you use to develop Semantic Web applications ?

2009-11-06T08:21:58Z

Not necessarily complete, but still a good reference for tools is the tool list maintained at W3C. And it is a wiki, so if something is missing, add it!