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Re: R:comment - RDFTM: Survey of Interoperability Proposals

From: Valentina Presutti <presutti@cs.unibo.it>
Date: Sat, 12 Mar 2005 03:55:14 +0100
Message-Id: <b608fff448aa4af180c3d97844bb301d@cs.unibo.it>
Cc: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>, <bernard.vatant@mondeca.com>, <public-swbp-wg@w3.org>
To: Fabio Vitali <fabio@cs.unibo.it>

Hi all,

first I apologize for being late. I had the possibility to read the 
emails just today because I was flying thuesday and wednesday. I know 
that Steve is already in the USA and that he is busy for other 
meetings. He is going back home in a few days.

Some comments on the current discussions about RDFTM follow:

---------
Peter:
The first problem that I see with the document is that it doesn't define
the two paradigms.  There are no references to any of the defining RDF
documents.  There are several references that could be considered to be
defining Topic Maps - however, these do not show up until very late in 
the
text and thus cannot be considered to be a definition for the purposes 
of
this document.

Bernard:
Fully agreed

Peter:
[Topic Maps also are undergoing change, from the ISO definition]...[ 
Which
version of Topic Maps is under consideration?  Does it matter?]

[This lack of a definition matters for reasons from both the RDF and the
Topic Maps side.  RDF has undergone a significant change in the last few
years from a pre-theoretic language with no firm foundation]...[Which 
version of RDF is
meant in the document?  Which version of RDF to the interoperability
proposals refer to?  As well, what is the place of RDFS in the document?
Is it included?  Is it excluded? ]

Bernard:
Good questions again.

Fabio:
Since it is a survey, it is not its purpose to describe anything more 
than
what is needed to be known in order to understand the existing 
proposals in
literature. As a survey, and not a position statement, it does not deal 
with
RDFS, OWL, or anything else, inasmuch the surveyed works deal with them
(which they do not).

If the group agree, we will add references to the versions of the 
documents
each proposal refer to.

Me:
The estimated size of audience for the survey document is 50 people, 
these people are supposed to be specially interested in the RDF/TM 
interoperability, hence familiar with both paradigms.
Nevertheless, it is useful and costless to add a brief paragraph with 
references to tutorial documents on the two paradigms.
The second deliverable, the guidelines, needs to take in consideration 
a more general audience, hence to be comprehensive.
The survey aims at giving a description of the existing proposals in 
order to identify slips and good ideas that will be precious when 
writing the guidelines document. This said, in my opinion, the specific 
version of RDF and/or Topic Maps to which each proposal refers to, and 
the changes the two paradigms are undergoing, do not really matter.
I agree with Bernard and Michael that Peter raises important issues, 
but in my opinion they have to be approached and discussed from now on 
(are out of scope for the survey).

---------
Peter:
The second problem is that many of the interoperability proposals 
predate
the finalization of the RDF Semantics.  Their current applicability is 
thus
very suspect.  The document needs to carefully consider this aspect of 
each
proposal.

Me:
The current applicability of the proposal is not important because it 
is our purpose to write the guidelines from scratch, although we will 
take in consideration the useful parts of the previous related works. 
On the other hand I agree with Fabio that, if needed, we can add 
references to the versions referred to by each proposal.

---------
Peter:
[The third problem is that RDF and Topic Maps belong to different
categories, at least so far as I can determine. ]...[How then can it be
determined whether a mapping is reasonable?  As well, the procedure 
defined
therein does not terminate.]

Fabio:
I am not sure I understand. The important bit about languages is to 
find out
whether people use them for the same purposes, not that they have been 
built
using the same principles or with the same level of formalism. It is a
matter of usage, not grammar. Is TM used for very similar purposes as 
RDF? I
think so. Therefore it is relevant to provide translation. Which will be
limited and inadequate and incomplete because of the difference in
formalism, but it will be better than no translation at all, if we 
really
believe that interoperability is a goal.


Me:
I agree with Fabio and strongly think that to provide translation is 
useful. And I also agree with Steve Pepper that we will rather provide 
a correct translation for a subset of the RDF/TM documents than a 
mapping appliable to all possible documents but with no guarantees of 
completeness (we discussed this matter privately and if I do remember 
correctly at the f2f meeting as well).

---------
Fabio:
Finally, I would propose that further discussions should be clearly 
marked
as belonging to one and only one of the following three categories:

  - The existence of RDFTM itself: whether there is any point in 
proceeding
with the interoperability guidelines given the complex differences 
between
RDF and TM approaches

Me:
I do not think that we have to discuss the usefulness of the TF now. It 
has been already done by the WG at the first meeting in Cannes. I think 
that now the WG would prejudge whether the TF will succeed or not.

---------
Fabio:
  - Modifications to the survey: What are the limits of the survey 
considered
as a survey, and not as a proposal, that need to be considered and 
solved
for the document to reach a final status

- Preparation for the guidelines: Supposing that we in fact decide to 
go on
with the RDFTM TF, what additional languages, theories, models and
approaches need to be considered in the next step of the activities of 
the
TF, namely in the delivery of an actual set of guidelines for
interoperability, that weren't discussed in the proposals surveyed.

Me:
Agree
---------

Now I try to briefly summarize the issues discussed at the last f2f WG 
meeting about the changes to apply to the Survey. I hope this could 
help to address a few doubts.
See also http://www.ontopia.net/work/survey-pres.html and 
http://www.w3.org/2005/03/04-swbp-irc#T19-05-11 (the discussion started 
at 16:10).

 From now on WG is intended as those members that were in Boston last 
week.

- The survey should be objective
- Nikita questioned wheter the survey is objective. We are going to ask 
her to give us more details (which are the points in the document she 
refers to) in order to reason on that.
- This first document is a Survey and we are not proposing any 
guideline, just trying to identify the pros and cons of each existing 
proposal.
- The survey will contain a brief paragraph with references to tutorial 
material on RDF and TM.
- Ok to say at least once that there are implementations and cite them 
(but not repeated reference).
- The test cases in the survey are intended just to be informative 
regarding naturalness.
- A more paragraph that discusses interoperability as it is impacted by 
"naturalness" (e.g. using semantic hacks)

These are the major changes to be done on the survey by the 17th(there 
are other smaller ones I don't mention here) . Then, we should start to 
work on the guidelines document.

Furthermore:
- The WG agreed about defining the guidelines with a semantic mapping 
approach
- The WG agreed the guidelines should propose a default solution. The 
mapping should work also without additional required information. To 
"require" something is a difficult SW thing
- The mapping should not cover OWL, but OWL should be used when it 
might have help.
- We will have a separate document for requirements and test cases 
(that goes with the guidelines document)

My best regards,
Valentina

--------------------------------------------------
Valentina Presutti

Phd Student of Computer Science
Computer Science Department
University of Bologna
Mura anteo Zamboni 7
Ph. +39 (0)51 20 94871
Fax. +39 (0)51 20 94510
Received on Saturday, 12 March 2005 02:58:09 UTC

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