[Pellet-users] Ontology stalls Pellet Redux

[Rinke Hoekstra]

Hi David,

Many thanks (again) for your efforts. These results really help in 
diagnosing the problems. I'm glad you clubbered exactly those 
troublesome classes, it would surely be nice if we could have some 
heuristics in place to steer this kind of 'accidental' merging ;)

> 
> There are many more classes in [2] Pellet could not perform satisfiability
> check within 5 seconds (151 of them).  And there are only 17 known
> unsatisfiability classes:
> 
> Valid_Rule Transaction Termination Argument2 Public_Body
> Continuation Rule Code Trade Legislative_Body Decision
> Mandate Initiation Assignment Delegation Act_of_Law
> Regulation

Some of these classes were added relatively late in the development of 
LKIF core (yes, I was working towards a deadline). Do you suppose fixing 
these could improve reasoning performance? Some statistics on the impact 
of unsatisfiable classes on performance would be really insightful to 
(naive) ontology builders.

> 
> There are only a small number of classes that can be profiled (37) in 5
> seconds.  So the clubbered classes were making the ontology that much
> harder. They are:
> 
> Argument, Assumption, Atom, and Exception (2).
> 
> The clubbered property is
> 
> overlap

I can understand Atom to be problematic (since it's the cause of Rule 
becoming inconsistent). Will have a look at the others... in fact, this 
list is to me more insightful than the list of unsatisfiable classes.

How is your work connected to the belief revision ontology analysis tool 
of SWOOP? I have a gut feeling that such analysis would point at least 
to some of these classes as causing the inconsistencies.

> 
> Though this type of analyses is suggestive and useful, it's not
> conclusive.  We still don't know exactly what axioms are causing the
> bottleneck, or how to determine the dependencies of 'hardness' (if any),
> or what choices were made in this particular profile run, or if we can
> give an estimate of performance prior to running the tableau.
> 
> These are research questions I am currently facing.  I am glad that there
> are interests from the community, and I hope to bring the tools and
> services to a reasonable state before I release it.  But hopefully soon :)

That would be great! I certainly hope to hear more about it (e.g. at OWLED?)

Best,

	Rinke


> 
> Cheers,
> 
> David
> -----
> 
> [1] http://www.mindswap.org/~tw7/work/profiling/others/lkif-all.owl
> [2] http://www.mindswap.org/~tw7/work/profiling/others/lkif-all-correct.owl
> 

-- 
----------------------------------------------
Drs. Rinke Hoekstra

Email: hoekstra at uva.nl   Skype:  rinkehoekstra
Phone: +31-20-5253499    Fax:   +31-20-5253495
Web:   http://www.leibnizcenter.nl/users/rinke

Leibniz Center for Law,         Faculty of Law
University of Amsterdam,           PO Box 1030
1000 BA  Amsterdam,            The Netherlands
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