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RE: CR Exit Criteria

From: Michael Schneider <schneid@fzi.de>
Date: Thu, 28 May 2009 12:04:57 +0200
Message-ID: <0EF30CAA69519C4CB91D01481AEA06A001413B0C@judith.fzi.de>
To: "Bijan Parsia" <bparsia@cs.man.ac.uk>
Cc: "OWL 1.1" <public-owl-wg@w3.org>
Hi Bijan!

>-----Original Message-----
>From: Bijan Parsia [mailto:bparsia@cs.man.ac.uk]
>Sent: Wednesday, May 27, 2009 7:24 PM
>To: Michael Schneider; OWL 1.1
>Subject: Re: CR Exit Criteria
>
>On 27 May 2009, at 17:53, Michael Schneider wrote:
>[snip]
>> Just to be clear: I don't claim that the criterion is too hard to
>> meet *per se*, which would really be an, erm, "exit criterion" for
>> OWL 2 Full. I don't see anything obviously "un-implementable" in
>> OWL 2 Full,
>
>Really? Can I ask what implementation experience that grounds this
>judgment? I'm not being snarky, but I think you are underestimating
>the implementation challenges. Even if you were building off a FOL
>reasoner, it doesn't seem trivial to me. There's also no literature
>to drawn on. Inventing reasoning algorithms is much harder, in my
>experience, than implementing one from a book.
>
>I'm not saying it's impossible, just that the uncertainy is pretty
>high. (And depends on what you mean by "obviously un-implementable".)
>
>[snip]
>>  But if one is about creating a serious implementation of OWL 2
>> Full, then this will almost certainly take much too long for this
>> working group to build one. The same would probably be true for an
>> OWL 2 /DL/ reasoner, if one were about implementing it from scratch
>> at the beginning of the CR phase.
>
>This last bit seems pretty wrong to me. Pellet is sort of a proof of
>concept that we could build such a thing (done, part time, for WebOnt
>CR). And the literature and general experience in building DL
>reasoners was much less then. And Evren and I were doing it from books.
>
>Now, I'm sure you could put together a test suite that would be, er,
>challenging to beat in this time frame. And I'm not saying it would
>be a super duper production system. But I think it's not so very
>likely, given a test suite that focused on language coverage (but
>also was "reasonable"). Heck, Boris builds reasoners to relax over
>bank holiday weekends :)
>
>For building an OWL 2 Full reasoner...well...it seems like research.
>It is closer to what building a reasonable SHOIN reasoner was back at
>webont (Ian and Uli had to do *research* before we could do it).
>
>(None of this should be construed as opposition to fairly easy exit
>criteria for OWL Full. But lets be clear on what is and is not likely
>possible here.)

So, to restate what I said before: I consider it to be *not* likely that 
the (now approved) CR criteria for OWL 2 Full are possible to be met 
within the time constraints of the CR phase.

And to confirm what you say above: I don't know about any literature, 
I consider it hard and non-obvious to implement OWL 2 Full, and I 
also consider the uncertainty to be high. This is all what I was about 
in my last mail. I certainly wouldn't have written the mail if I would 
think that OWL 2 Full was easy and fast to be implemented.

Concerning what I said about "obviously un-implementable", you seem to 
interpret more into this notion compared to what I intended. I just wanted 
to express that I cannot point to a specific feature of the language that 
would make me say: "Forget about implementing OWL 2 Full!", which would, 
of course, be a show stopper for having this language under the W3C flag. 
Actually, I really believe that one can do significantly better than, say, 
what Jena provides (without hunting for unachievable theoretical 
completeness, though). But it will take a lot of effort, and most probably 
some new approach to pursue. Well, the book has to be written first, 
before one can implement from it. :) 

Btw: What I said about "building DL from scratch" was (as in my last 
week's mail) meant for the imagined case that there would be 
*no* existing theoretical foundation available (no books to implement 
from). My (maybe hidden) argument was that I do not see why 
the desire to have an ontology language for the SemWeb would 
necessarily be bound to existing research in the field of 
implementing knowledge representation languages. The WebOnt WG 
would have certainly be able to produce a sort of OWL even without 
such theoretic work. But I wonder what the CR criteria would have 
been in such an "unlucky" situation.

>Cheers,
>Bijan.

Cheers,
Michael

--
Dipl.-Inform. Michael Schneider
Research Scientist, Dept. Information Process Engineering (IPE)
Tel  : +49-721-9654-726
Fax  : +49-721-9654-727
Email: michael.schneider@fzi.de
WWW  : http://www.fzi.de/michael.schneider
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Received on Thursday, 28 May 2009 10:05:37 UTC

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