W3C home > Mailing lists > Public > public-xg-urw3@w3.org > July 2007

RE: [URW3 public] OWL extensions [was Re: [URW3] ... three questions based on the last telecon]

From: Giorgos Stoilos <gstoil@image.ece.ntua.gr>
Date: Thu, 26 Jul 2007 05:17:28 +0300
Message-Id: <200707251617.l6PGHFxL000971@manolito.image.ece.ntua.gr>
To: <Peter.Vojtas@mff.cuni.cz>, "'Ken Laskey'" <klaskey@mitre.org>
Cc: "'Kathryn Blackmond Laskey'" <klaskey@gmu.edu>, <public-xg-urw3@w3.org>, "'Umberto Straccia'" <umberto.straccia@isti.cnr.it>

Hi Peter,

There are quite some drawbacks of this "localized computational" model.

So, a user queries "get me all tall people". Now in order for the system to
return the exact height of each person and then a local processing method to
fuzzify the heights the following should hold.
1) The (local) system should rewrite the query to "get me all people + their
heights"
2) The (local) system should fuzzify the returned heights (according to user
preferences).
3) The (local) system should apply a (probably) heavy reasoning algorithm to
reason with the concept tallness (in case Tall is a concept in some OWL
ontology).
3b) Te last also might imply that the user has created (or imported from the
web) an ontology about people (heights, weights, ages, etc.)
All the above suggest a) much computational complexity on the user side and
b) that the user is experienced and capable enough to create fuzzification
functions and finally import or create OWL ontologies.

After some thinking I do not see what is the problem on someone making for
me the decision that 178cm is Tall to degree 0.6. When a user (at least from
my point of view) queries "get me all tall people" he expects to get all
tall people in some descending order. So John who is 178cm will be returned
(say) 5th with degree 0.7, as he will also be returned 5th when using some
different local but homomorphic fuzzification function. 

In any case to my point of view the important thing is not to say to which
degree 178cm is tall, but to reason wrt fuzziness and return an order set of
results, reflecting users intuition.

-gstoil


> -----Original Message-----
> From: public-xg-urw3-request@w3.org [mailto:public-xg-urw3-request@w3.org]
> On Behalf Of Peter Vojtas
> Sent: Wednesday, July 25, 2007 2:09 PM
> To: Ken Laskey
> Cc: Kathryn Blackmond Laskey; public-xg-urw3@w3.org; Umberto Straccia
> Subject: Re: [URW3 public] OWL extensions [was Re: [URW3] ... three
> questions based on the last telecon]
> 
> 
> Example is nice, but I would stress to use web examples, even if it is in
> an article on the web, somebody says ...XY...is tall, but he/she does not
> claim tall:0.7, we have to tend to more realistic web-examples (e.g. in
> our use cases). I agree it depends on the society, circumstances,.... are
> we going to model also these? Peter
> 
> 
> Please note my changed address Peter.Vojtas@mff.cuni.cz
> 
> 
> 
> ----- Original Message -----
> From: Ken Laskey [mailto:klaskey@mitre.org]
> To: Peter.Vojtas@mff.cuni.cz
> Cc: Kathryn Blackmond Laskey [mailto:klaskey@gmu.edu], public-xg-
> urw3@w3.org, Umberto Straccia [mailto:umberto.straccia@isti.cnr.it]
> Subject: Re: [URW3 public] OWL extensions [was Re: [URW3] ...  three
> questions   based on the last telecon]
> 
> 
> > Peter,
> >
> > We would always like to have "exact" information, but any measurement
> > has a degree of inexactness/uncertainty based purely on the preciseness
> > of the measuring instrument.  At a crime scene, a suspect may be
> > described as tall but the accuracy depends on what the observer
> > considers tall, the vantage point from which the observer saw the
> > suspect, and whether the suspect was wearing shoes with heels.  Also,
> > was the suspect tall in the context of a society where the average
> > height is 162 cm or 175 cm?  Making use of the fact that the suspect
> > was "tall" requires many assumptions, most of which are implied in
> > conversation but never explicitly stated.
> >
> > What does this tell us about what needs to be represented in terms of
> > uncertainty?
> >
> > Ken
> >
> > On Jul 24, 2007, at 9:29 AM, Peter Vojtáš wrote:
> >
> > >
> > > I personaly would prefer to know the exact height of John and decide
> > > on my background and intention whether he is or not tall.
> > >      So I am afraid that I do not understand where such an information
> > > can appear
> > > Peter
> > >
> > >
> > > Please note my changed address Peter.Vojtas@mff.cuni.cz
> > >
> > >
> > >
> > > ----- Original Message -----
> > > From: Kathryn Blackmond Laskey [mailto:klaskey@gmu.edu]
> > > To: Umberto Straccia [mailto:umberto.straccia@isti.cnr.it],
> > > public-xg-urw3@w3.org
> > > Subject: Re: [URW3 public] OWL extensions [was Re: [URW3] ...  three
> > > questions  based on the last telecon]
> > >
> > >
> > >>
> > >>
> > >>>> .... you can extend the language and the inference mechanism or
> > >>>> express and process the uncertainty within the standard language.
> > >>>>
> > >>>> tall(John) : 0.7
> > >>>>
> > >>>> vs
> > >>>>
> > >>>> tall(John, 0.7)
> > >>>>
> > >>>> (... in both cases, without saying what 0.7 represents)
> > >>
> > >> Independent of which way we go on tall(John) : 0.7 or tall(John,0.7),
> > >> it will not be enough just to annotate sentences with a number
> > >> expressing some degree of certainty or plausibility or membership or
> > >> whatever.  To do probabilistic reasoning, we need to be able to make
> > >> conditional independence statements, and to express conditional
> > >> probabilities. To do probability tractably depends on representations
> > >> composed out of local modules, and these local modules are
> > >> parameterized by conditional probabilities, not absolute
> > >> probabilities.
> > >>
> > >> K
> > >>
> > >>
> > >
> > >
> > ------------------------------------------------------------------------
> > -----
> > Ken Laskey
> > MITRE Corporation, M/S H305      phone: 703-983-7934
> > 7151 Colshire Drive                         fax:       703-983-1379
> > McLean VA 22102-7508
> >
> >
Received on Wednesday, 25 July 2007 16:17:40 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Wednesday, 30 April 2008 09:52:44 GMT