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

From: Giorgos Stoilos <gstoil@image.ece.ntua.gr>
Date: Mon, 16 Jul 2007 14:33:46 +0300
Message-Id: <200707161133.l6GBXfT1022363@manolito.image.ece.ntua.gr>
To: "'Mike Pool'" <mpool@convera.com>, <Peter.Vojtas@mff.cuni.cz>, "'Ken Laskey'" <klaskey@mitre.org>
Cc: <public-xg-urw3@w3.org>

Hi Mike,

See mine too below :).

> -----Original Message-----
> From: public-xg-urw3-request@w3.org [mailto:public-xg-urw3-request@w3.org]
> On Behalf Of Mike Pool
> Sent: Monday, July 16, 2007 1:55 PM
> To: Peter.Vojtas@mff.cuni.cz; Ken Laskey
> Cc: public-xg-urw3@w3.org
> Subject: RE: [URW3 public] Re: [URW3] ... three questions based on the
> last telecon
> 
> 
> Hi, Peter,
> 
> See my responses below within [mjp][/mjp] tags.
> 
> Mike
> 
> -----Original Message-----
> From: Peter Vojtas [mailto:Peter.Vojtas@mff.cuni.cz]
> Sent: Monday, July 16, 2007 4:24 AM
> To: Ken Laskey
> Cc: public-xg-urw3@w3.org; Mike Pool
> Subject: [URW3 public] Re: [URW3] ... three questions based on the last
> telecon
> 
> Dear colleaguess (sent to public list and separately to KL and MP),
> 
> as I have pointed in the ontology page in Top Level comments by P.
> Vojtas is there a mistake?, see
> http://www.w3.org/2005/Incubator/urw3/wiki/is_there_a_mistake%3F
> 
> by W3C standards, basic information unit is a triple (subject,
> predicate, object) which can be true or false in a structure (to avoid
> discussion whether it is a sentence or proposition, w3c uses statement).
> 
> [mjp]
> An RDF triple is designed to represent something, i.e., propositions,
> but an RDF statement is just another means of expression.  If you write
> a sentence in RDF triple terminology and I write the same one in KIF, in
> virtue of what are they equivalent?  In virtue of the fact that they
> represent the same proposition, I would claim.
> 
> Perhaps we want to argue that we should use RDF triples to represent
> these propositions, and in terms of representational syntax, say, for
> example, as you do below, that triple3 hasUncertainty Y.  (That's along
> the lines of what I'd do but I'd argue that we want to allow for a
> formalism in which 'hasUncertainty' can link an uncertainty value to any
> well-formed formula (in a full first order logic) and that we may need
> another relation, hasUncertaintyAccordingTo, that could be a ternary
> relation linking wffs, agents and uncertainty values.)   I'm a little
> squeamish about constraining ourselves to triples from the outset as
> they notoriously lack sufficient expressiveness without appealing to ad
> hoc "reified relationships" (which also seem to pull us out of our
> first-order world).  (To take a simple example, I can't
> straightforwardly represent the fact that Joe was a Microsoft employee
> in 2001 using triples, so I think it's a bit dangerous to assume from
> the outset that triples will be adequate for the representational needs
> we might have. )
> 
> I think that the representational adequacy of RDF, and the triple
> vocabulary, for uncertainty reasoning should be one of the things that
> we talk about.  So our ontology and representational approach shouldn't
> assume at the outset that it is adequate for representation.
> 
> [/mjp]
> 
> 
> see e.g. http://www.w3.org/TR/rdf-primer/ for following example
> 
> http://www.example.org/index.html has a creation-date whose value is
> August 16, 1999
> 
> here we can use reification for another writing asigning an identifier
> to the statement
> 
> ex:triple1	rdf:type	rdf:Statement
> ex:triple1	rdf:subject 	http://www.example.org/index.html
> ex:triple1	rdf:predicate 	http://purl.org/dc/elements/1.1/creator
> ex:triple1	rdf:object 	http://www.example.org/staffid/85740
> ex:triple1	ex:creator	http://www.example.org/staffid/85741
> 
> THIS CONSTRUCTION IS VERY USEFULL IN OUR CASE
> 
> especialy in our ontology discussion the triple
> 
> urw3:Sentence  	urw3:hasUncertainty  urw3:Uncertainty
> 
> should be by my opinion rewritten as
> 
> urw3:triple2	rdf:type	rdf:Statement
> urw3:triple2	rdf:subject 	urw3:Sentence
> urw3:triple2	rdf:predicate 	urw3:hasUncertainty
> urw3:triple2	rdf:object 	urw3:Uncertainty
> urw3:triple2	ex:creator	urw3:Mitch
> 
> and instance ( consider also an "instance"  ex:triple1
> urw3:hasUncertainty  urw3:0.9)
> 
> as, e.g.
> 
> urw3:triple3	rdf:type	rdf:Statement
> urw3:triple3	rdf:subject 	ex:triple1
> urw3:triple3	rdf:predicate 	urw3:hasUncertainty
> urw3:triple3	rdf:object 	urw3:0.9
> urw3:triple3	ex:creator	urw3:Peter
> urw3:triple3	urw3:tool	urw3:Bayes
> 
> [mjp]
> Yes, this seems reasonable to me, but I don't think it goes far enough
> to handle all our representational needs.
> 
> For example, I may also want to say:
> ((urw3:triple3 AND urw3:triple4) OR urw3:triple9) hasUncertainty .1
> 
> Or that the probability that Joe worked at Microsoft in 2001 is .3, or
> that according to Fred the probability that Joe worked at Microsoft in
> 2001 is .2 and according to Sally it is .4.
> 
> [/mjp]

Guys, I don't think that using RDF triples to represent not only uncertainty
but even knowledge on the web has anything to do with reason :); even worse
using reification.

As I said in my previous mail, I don't see how language extensions (or ways
to represent uncertainty using W3C standards) have anything to do with an
uncertainty ontology? 

Moreover, is it in this group's goal to propose such extensions or to
identify them?

Finally, if we want to look into such extensions I am in favour of OWL and
not RDF.

-gstoil

> 
> The example with the german sentence (Mathias can help) is very usefull
> (words morgen and Morgen are problematic) because it shows what can
> happen. MP assigns an uncertainty to his own translation by expression
> "if I've translated correctly". Nevertheless, by my opinion "Es regnet
> morgen" is a problematic sentence because "Es regnet" is about present
> and "morgen" with lower case m in the begining means tomorrow, it is an
> adverb. So a problem accurs, what to do with a gramaticaly wrong
> sentence (note that the word sentence I use here in the linguistical
> sense, which in the W3c terminology can by defined appropriately by
> corresponding triples, by defining predicates like subject, verb,
> object, mode (manner), place and time). I would say either "Es regnet
> heute morgen" or "Es wird morgen regnen".
> 
> [mjp]
> I would just chalk this up to my trying to use Babelfish to get a German
> sentence.   A malformed sentence can just be ignored, I think.
> [mjp]
> 
> 
> Sorry for such a long mail, concluding I would like to say, please let
> us use w3c terminology (arguing for necessity of an extensions of
> standards we need be compatible with current standards). Next, the above
> 
> example shows we need to define our own prefix and rdf vocabulary for
> uncertainty ontology.
> 
> [mjp]
> Thanks for your response, much appreciated.  I now fully understand the
> point you were making in the meeting.
> [/mjp]
> 
> Greetings Peter
> 
> 
> 
> >     *From:* Mike Pool
> >     *Sent:* Friday, July 13, 2007 3:25 PM
> >     *To:* public-xg-urw3-request@w3.org
> >     *Subject:* three questions based on the last telecon.
> >
> >     Hi, all:
> >
> >     We've been having some great discussions during the meetings and
> I'd
> >     like to pick up a few threads that came up in the last meeting.  I
> >     reread these as I was trying to write up the minutes:
> >
> >     1)
> >     Peter suggested that we use w3c standards as our guide for the
> >     meaning of 'proposition'.  Peter, do you know if this is defined
> >     somewhere by the w3C.  Could you point us to the definition?
> >
> >     2)
> >     I argued that propositions, in the sense of the meaning of a
> >     sentence that is invariant through all the paraphrases and
> >     translations of the sentence, rather than assertions or sentences
> as
> >     the kinds of things that hold probability values.
> >
> >     Kathy noted in the meeting that a problem with this definition is
> >     that a system might assign different uncertainty values to 2
> >     different logically equivalent sentences.   I can imagine that
> this
> >     is possible, but where it occurs I would think it nothing more
> than
> >     a weakness in the system, not in the definition I've suggested.
> For
> >     example, I might misunderstand 'Es regnet morgen' as 'it will rain
> >     this morning' rather than 'it will rain tomorrow' (if I've
> >     translated correctly) and assign it a different probability value
> >     than that which I'm assigning to 'it will rain tomorrow'.  But I
> >     think that anyone who observed my doing this would point out that
> >     it's a contradiction, i.e., that since these things have the same
> >     meaning, I'm obligated to assign them the same probability value.
> >      In other words, it is in virtue of their representing the same
> >     proposition that I'm obligated to assign them the same probability
> >     value.    So, I think this only helps to underscore the fact that
> >     when we explore our intuitions, we believe that propositions are
> the
> >     real p.v. holders.
> >
> >     3)
> >     Anne, you said at one point that "not all beliefs can
> appropriately
> >     be represented as numerical values" and that it "glosses over
> >     inconsistencies - beliefs may be logically incompatible".  I was
> >     intrigued by the suggestion, can you say more?
> >
> >
> >     Again, thanks all for a stimulating telecon on Wednesday.
> Apologies
> >     in advance if this address is not the right forum for these
> >     discussions.
> >
> >     Best regards,
> >
> >     Mike Pool
> >
> >     --------------------------------
> >
> >
> >
> >
> ------------------------------------------------------------------------
> -----
> >
> > Ken Laskey
> > MITRE Corporation, M/S H305 phone: 703-983-7934
> > 7151 Colshire Drive fax: 703-983-1379
> > McLean VA 22102-7508
> >
> 
Received on Monday, 16 July 2007 11:34:10 GMT

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