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RE: Comments to Rules Working Group Charter Draft $Revision: 1.60$ (Part II)

From: Giorgos Stamou <gstam@softlab.ntua.gr>
Date: Tue, 13 Sep 2005 11:53:33 +0300
Message-Id: <200509130854.j8D8rxGn004350@theseas.softlab.ece.ntua.gr>
To: "'Dave Reynolds'" <der@hplb.hpl.hp.com>
Cc: "'Sandro Hawke'" <sandro@w3.org>, <public-rule-workshop-discuss@w3.org>

> -----Original Message-----
> From: Dave Reynolds [mailto:der@hplb.hpl.hp.com]
> Sent: Monday, September 12, 2005 3:36 PM
> To: Giorgos Stamou
> Cc: 'Sandro Hawke'; public-rule-workshop-discuss@w3.org
> Subject: Re: Comments to Rules Working Group Charter Draft $Revision:
> 1.60$ (Part II)
> Giorgos Stamou wrote:
>  >> [der]
> >>Is this a question we could pose to the Semantic Web Best Practices
> >>working group?
> >
> >
> >  [Giorgos Stamou]
> >
> > Well, I think this is a good idea. And since I am a member of the
> Semantic
> > Web Best Practices Working Group (also co-chairing a new Task Force on
> > Multimedia Annotation in the Semantic Web, an area that needs
> uncertainty
> > representation) I could certainly start this discussion there, as well.
> That sounds good, thank you. I'll look forward to seeing how the
> discussion
> goes. I think the issue of how to handle uncertainty on the semantic web
> is
> a bigger question than how to generalize logical rules.
[Giorgos Stamou]

I agree! Let's start from generalizing the logical rules.

> > The work on fuzzy logic has been started in 1965. And, in its late form
> (see
> > the book [Petr Hayek, Metamathematics of Fuzzy Logic, Kluwer Academic
> > Publishers 1998]), it is really a general framework covering several
> other
> > relevant theories of multi-valued logic. It is a clear and sound
> framework.
> I last used it in the early 80's so I'm aware it has been around for a
> while.
> > Still, it is not complete! But I think most theories in logics are not
> > "complete". I also think that the W3C Standardization process does not
> only
> > cover "complete" theories. Moreover, there is no final "agreement" of
> the
> > community that discusses the charter, in basic issues of classical logic
> > (consider the example of the usefulness of monotonic or non-monotonic
> > logic).
> > So, I understand your argument but I don't really think that we are very
> > confident with several other language extensions fairly included in the
> > charter. Moreover, obviously I did not propose uncertainty for the core
> > language. I only proposed to be included in the strongly-motivated in-
> scope
> > extensions to be considered.
> Perhaps you are right that uncertainty representation is as settled an
> issue as how to combine non-monotonic rules with RDF and OWL but the
> latter
> is hardly an uncontroversial issue :-)

[Giorgos Stamou]

Well, I am not willing to get in this discussion... In any case, uncertainty
handling is very useful in both monotonic and non-monotonic reasoning.

>  >> [der]
> >>For good or ill, the emphasis of the draft charter is not on an
> >>implementable language but on an interlingua for exchange of rules
> >>between existing systems. It's not clear that the uncertainty use cases
> >>really fall into the interlingua remit. I would have thought that the
> >>issues of successful exchange and integration of rules involving
> >>uncertainty reasoning would be much greater that those of simply using
> >>fuzzy inference within a single system. Whereas the use cases seemed to
> >>want an implemented language they could use without a particular need
> >>for rule exchange.
> >
> >
> > [Giorgos Stamou]
> > I think they fall in the same framework. In the case you have different
> rule
> > systems dealing with uncertain and fuzzy rules, they should exchange
> these
> > rules in a similar form, in order to be able to deliver the uncertainty
> and
> > fuzziness.
> The point I was trying to make was that for non-fuzzy rules there are a
> lot
> of languages in use which people seem to want to exchange rules between,
> so
> I can believe that it makes sense to develop an interlingua now. Whereas
> it's not so clear that there are so many fuzzy rule languages that
> fuzzy-rule exchange is currently the presssing issue. It seemed more like
> the uncertainty use cases were asking for *a* solution rather than a way
> for their many solutions to interoperate.

[Giorgos Stamou]

In the Workshop, the industry requirement about uncertainty was clear. In
several applications of the Semantic Web (that of course involve sharing and
reuse issues in order to take advantage of the Semantic Web and thus they
need this interlingua) uncertainty handling is important. And the right way
to do this is not to construct something new (a new fuzzy rule language or
interlingua), but add an optional language feature to the W3C Rule Language.
It's now something simple that giving the standardization procedure of W3C
will be really complicated in the future.

>  >>[der]
> >>The stated requirement to "generalize the two-valued Boolean logic of
> >>{0,1} into the interval [0,1]" seemed somewhat directed towards a fuzzy
> >>logic solution.
> >
> >
> > [Giorgos Stamou]
> > If it is because of the "[0,1]" requirement we could change it, although
> > fuzzy logic will also follow it (other relevant theories would not).
> > However, I think "[0,1]" is more preferable since it is a reasonable
> > extension of {0,1}.
> The "[0,1]" bit is part of it.
> In addition, the use cases presented seemed like they might be amenable to
> statistical techniques and were in domains where, IMHO, a precise
> understanding of the probability of an incorrect recognition is mandatory.
> It's not clear that all such statistical procedures can be thought of as
> generalizations of boolean logic.

[Giorgos Stamou]

In my understanding topics as: "uncertain class descriptions", "fuzzy
reasoning", "uncertainty about class membership of objects", "uncertainty in
sensor reading", etc (taken from distinct use cases) were the most commonly
discussed in the Workshop. I am certain that you agree the text I sent to
Sandro covers these issues. Anyway, there is no problem, it is not necessary
for the requirement of uncertainty to be included in the charter in exactly
this form. This text was only a proposal and of course it will be reviewed.

> > I understand that some language extensions will not be included and I
> > respect your opinion that there is no clear need for the uncertainty
> > extension to be included from the beginning (although if I correctly
> > understand you are positive to be included in the future). I also
> recognize
> > the very difficult and critical work of people writing the charter in
> order
> > to fairly balance it between several other people needs and wants.
> > But let me insist that it is fair enough to include the issue of
> > uncertainty, which was mentioned a lot by industrial participants in the
> > Workshop (which was organized mainly in order to find the industry
> > requirements), nobody is really against it, and does not change the work
> of
> > anybody.
> Fair enough, I think I've expressed my reservations sufficiently and will
> shut up now.
> Dave

[Giorgos Stamou]
Thank you for this very interesting discussion.
And since there are no other objections and you are generally positive with
some reservations, I will also shut up and wait for the next version of the
charter :-)
Received on Tuesday, 13 September 2005 08:55:50 UTC

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