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Re: Model-specific identity for anon resources, and its representation: A new issue?

From: Graham Klyne <Graham.Klyne@Baltimore.com>
Date: Sat, 16 Jun 2001 21:13:48 +0100
Message-Id: <5.0.2.1.2.20010616204450.0309a020@joy.songbird.com>
To: Sergey Melnik <melnik@db.stanford.edu>
Cc: w3c-rdfcore-wg@w3.org
Sergey,

I vaguely remember this being raised, and must say I have deep reservations 
about that approach.

Right now I cannot say exactly why I think this is a problem, and I won't 
fight the case here, other than to note that I might object later if/when I 
can crystalize my concerns.

(Part of my objection is that any mechanism that is based on merely 
statistical uniqueness (i.e. digest-based) has no place in the core of the 
RDF framework.  In an appendix to RFC 2938, I have calculated some 
probabilities of collision using MD5;  the numbers of digest values in use 
does not need to be astronomically large (c. 10^18 or so) before the 
probability of collision becomes quite significant.  Applications may 
choose to take such statistical chances, but I don't think a fundamental 
technology framework like RDF should do so.)

#g
--

At 06:58 PM 6/15/01 -0700, Sergey Melnik wrote:
> > do you really mean this last claim?
> > I suspect you meant that all parsers should assign a predictable genid
> > given a common RDF/XML description mentioning a resource. 'all parsers
> > should assign the same genid to the same resource' would be magic, since
> > many times parsers won't have that information accessible.
>
>Dan,
>
>just to provide a pointer, a whole while ago I proposed an algorithm for
>doing exacty that "magic". A summary of the proposal can be found at
>http://nestroy.wi-inf.uni-essen.de/rdf/sum_rdf_api/ under "URI
>generation for anonymous resources" (by Peter Hannappel and Reinhold
>Klapsing). I believe, if needed, this algorithm can be tweaked to
>eliminated the problems wrt using XOR (as pointed out by Brian long
>ago).

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Graham Klyne                    Baltimore Technologies
Strategic Research              Content Security Group
<Graham.Klyne@Baltimore.com>    <http://www.mimesweeper.com>
                                 <http://www.baltimore.com>
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Received on Saturday, 16 June 2001 16:20:19 EDT

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