[Pellet-users] tracing back inconsistency

[Christian Halaschek-Wiener]

Hi Luigi,

My first thought is that this issue is due to the technique for  
debugging/tracing which is used in Swoop. To my knowledge (Evren and/ 
or Bijan correct me if I'm wrong), the approach implemented in Swoop  
is not glass-box tracing as discussed in [1] and implemented in  
Pellet (for ABox assertions only at this time). In some cases the  
technique in Swoop can hang, as you are observing. As Pellet uses an  
internal tracing technique (again only for ABox assertions), it  
finishes in a timely manner. We are currently working on coding TBox  
tracing in Pellet and we hope to get a release out soon. Once this is  
done, we will integrate it into Swoop and this issue will be  
resolved. Evren and/or Bijan, please let me/us know if I missed  
something here.

Regards,
Chris


References
[1] Bijan Parsia, Evren Sirin, Aditya Kalyanpur "Debugging OWL  
Ontologies", In The 14th International World Wide Web Conference  
(WWW2005), Chiba, Japan, May 2005.


-- 
Christian Halaschek-Wiener
PhD Candidate, Dept. of Computer Science
GRA, MINDSWAP Research Group,
University of Maryland, College Park
Web page: http://www.mindswap.org/~chris




On Jan 16, 2007, at 1:26 PM, Luigi Iannone wrote:

> Hi all,
>
> I have built an ontology ( available at
> http://www.csc.liv.ac.uk/~luigi/PIPSOntologyRework/PIPSNutrition.owl)
> and I asked programmatically to Pellet for its consistency. Pellet  
> says
> it is not and gives me a reason. The problem is that I cannot make  
> a lot
> out of such reason. Here's what it says:
>
> WARN [main] (KnowledgeBase.java:892) - Inconsistent ontology. Reason:
> Individual
> http://www.pips.eu.org/ontologies/ 
> nutrition#NutsServingRecommendation is
> forced to belong to class http://www.pips.eu.org/ontologies/food#Food
> and its complement
>
> This is because the individual belongs to ServingRecommendation  
> that is
> disjoint with Food.
>
> The problem is that I cannot find out how come such individual is  
> in the
> extension of Food
>
> I tried to use the debug facilities in SWOOP but, after Pellet  
> completes
> the reasoning in less than one second, it hangs on ages (with 512 max
> heap space) for rendering the ontology and, after almost an hour,  
> it has
> not finished yet, therefore, I cannot click on the famous why link in
> order to pinpoint which are the axioms responsible for that  
> inconsistency.
>
> Can anyone help on that? I am sure I am missing something.
>
> Thanks in advance,
>
> Luigi
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