Re: SSN ontology not classifying with Pellet and Fact++

Hi Monika,

Thanks for the interest in the SSN ontology.

I’ve just tested with Pellet, Fact++ and Hermit and I get the same behaviour as you.

Firstly, no, this behaviour wasn’t present at the time we developed the ontology.  However, about 2 years ago, someone asked a similar question.  At that time, Fact++ didn’t seem to work, but Pellet was working for me - I can’t remember what version.

I’ve done some digging and this is what I get:

- Fact++ doesn’t work because DUL uses an xsd:date.  I’m not sure what’s happened here.  xsd:date used to be part of the OWL2 development, but in the final versions it disappeared from the built-in datatypes.  If I change these to xsd:dateTime, then Fact++ classifies the ontology just fine.  So I expect this is simply because DUL relied on something that ended up not being in the final OWL2 specs.

- Pellet fails for the SSN ontology and DUL, but works for SSN without DUL (the xsd:date trick had no effect).  So I’m not sure what the reason is and it would be hard to track down given the size of DUL.

Given how many times both the SSN and DUL have been used in the past, I’d expect that this issue isn’t a problem with either ontology and is more likely an issue in recent versions of Pellet.  I’d suggest that you either use Hermit or try an older version of Pellet.  Or you could use the SSN without DUL - if you aren’t making use of the DUL alignment.  That classifies just fine in all 3 reasoners.  Either download and edit out the DUL alignment or grab the modularised version at http://lists.w3.org/Archives/Public/public-ssn-cg/2012Jun/0000.html

That last suggestion wouldn’t be the ‘proper’ SSN, but maybe this is just evidence that a new version is required.

Michael





On 16 May 2014, at 6:02 am, Monika Solanki <msolanki.mailings@gmail.com<mailto:msolanki.mailings@gmail.com>> wrote:

I am trying to classify the SSN ontology at

http://purl.oclc.org/NET/ssnx/ssn

The Pellet 2.3.1 command line refuses to classify and throws an out-of-memory error. In Protege, if I load the ontology and classify it using Hermit, the classification works fine. If I use Pellet or Fact++ through Protege, the ontology fails to classify. Is this a known behaviour ?

I need to import SSN in my ontology and this makes me concerned about doing so.

Thanks,

Monika