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Re: proposal - Fragments redux (unifying the threads under Issues 75-80)

From: Jim Hendler <hendler@cs.rpi.edu>
Date: Thu, 29 Nov 2007 12:06:55 -0500
Message-Id: <F858B57B-D971-4605-986B-977EFD7D4C49@cs.rpi.edu>
To: Carsten Lutz <clu@tcs.inf.tu-dresden.de>
Cc: Bernardo Cuenca Grau <bcg@cs.man.ac.uk>, OWL Working Group WG <public-owl-wg@w3.org>



On Nov 29, 2007, at 2:44, Carsten Lutz <clu@tcs.inf.tu-dresden.de>  
wrote:

> On Wed, 28 Nov 2007, Jim Hendler wrote:
>>
>> well, it's not so much motivated by computational properties, see  
>> out in the real world there's people who just implement fast  
>> engines and don't worry so much about the details...
>
> Sorry to object, but IHMO this approach is precisely why the original
> OWL Lite was broken. And I understood we wanted to fix this?! We  
> should
> at least understand the computational properties of the fragments we
> are selecting.
>

IMO, its because we worried too much about theory that lite is broken,  
but thats neither here nor there. I never said computation wasn't a  
factor to be taken into account, but it's also not the only factor to  
be taken into account.  We are not writing research papers here, we  
are trying to help people build real web apps!


>> but, what is the motivator is that several studies of ontologies  
>> including the one we did at Maryland a couple years back [1], a  
>> recent study by Guus and Frank van Harmelen (I don't have a  
>> reference, was told about it by Guus and Frank), and a study by  
>> UMBC of Swoogle results (blogged in eBiquity last year) all showed  
>> that most of the currently most used ontologies (including FOAF)  
>> pretty much fall into this class.  I've also met with several  
>> companies involved in OWL startups, and this is the expressivity  
>> that most of them say is most useful.
>
> Good to know. On the other hand, they could just use OWL full if it
> turns out that that particular fragment is neither computationally
> easier nor more efficiently implementable than the whole OWL-DL. I'd
> like to support Bernardo when he says that years of research have been
> invested into the other fragments, they are very well-understood, and
> were very carefully build. We should definitely take advantage of
> that. Regarding usefulness: EL++ *is* used by loads of real-world
> ontologies, and that was the case even before EL++ was "discovered" by
> the DL research community. No studies needed. :)
>
> Never mind, I couldn't resist to point these out now. Maybe this is
> best discussed at the Manchester F2F.
>
> greetings,
>        Carsten
>
> --
> *      Carsten Lutz, Institut f"ur Theoretische Informatik, TU  
> Dresden       *
> *     Office phone:++49 351 46339171   mailto:lutz@tcs.inf.tu-dresden.de 
>      *
Received on Thursday, 29 November 2007 17:07:36 GMT

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