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Re: [rdfmsQnameUriMapping-6] Algorithm for creating a URI from a QName in RDF Model?

From: Patrick Stickler <patrick.stickler@nokia.com>
Date: Fri, 31 May 2002 15:46:06 +0300
To: ext Graham Klyne <GK@ninebynine.org>
CC: www talk <www-talk@w3.org>
Message-ID: <B91D4B3E.15DAD%patrick.stickler@nokia.com>

Fair enough.

And of course I wasn't saying there was no place for proprietary
solutions. I guess it all boils down to where one would like to
draw the line -- or how general one feels certain functionality is
(the more general, broadly used, the greater the motivation for



On 2002-05-31 14:35, "ext Graham Klyne" <GK@ninebynine.org> wrote:

> Patrick, I don't really disagree with much of what you say here.  I don't
> plan debate the finer points.  But I'll suggest that even in an open
> network there's a place for proprietary usage.  Many of the more successful
> standards started out as proprietary usage which found a wider audience.
> In my case, the /id.../ convention is my way of informally indicating an
> intended usage.  The actual usage will determine the appropriate response
> when trying to retrieve a document.
> As for using RDF to expose information about the URI usage within a domain,
> I think that's a fine idea, and another debate.  I don't yet feel the need
> to enter those waters.
> #g
> --
> At 02:20 PM 5/30/02 +0300, Patrick Stickler wrote:
>> On 2002-05-30 12:07, "ext Graham Klyne" <GK@NineByNine.org> wrote:
>>> At 09:15 AM 5/30/02 +0300, Patrick Stickler wrote:
>>>> On 2002-05-29 15:05, "ext Graham Klyne" <GK@ninebynine.org> wrote:
>>>>> .. (e.g. I have a
>>>>> convention in my web space that http://id.ninebynine.org/ is used for
>> such
>>>>> abstract identifiers.  I think it helps to clarify the intent, but it
>>>>> doesn't make all the problems go away, such as my second question above.)
>>>> Tut, tut, Graham ;-)
>>>> How is this any different from voc://ninebynine.org/... except that the
>>>> convention is not standardized and the semantics that the URI denotes an
>>>> abstract resource is specific/proprietary to your own practices?
>>> Exactly that!
>>> It's not standard, and it's something that I as owner of the domain space
>>> choose to do.
>>> It does nothing to change the universal elements of interpretation of a
>> URI.
>> But a human (or software agent) would have to understand the prose
>> provided on your site to know that a 404 response was not actually
>> a true error, but that the resource is simply not web-accessible.
>> I.e. a client that recieves an http: URI expects it to resolve to
>> something. It has a traditional interpretation as denoting a web
>> accessible resource. If the resource is e.g. the abstract concept
>> of "love" then anything that an HTTP server might return with a 1xx
>> response is misleading to the client, since that resource itself
>> could not be returned, only knowledge about that resource.
>> If having 'id.' as part of one of your URLs helps you, fine, but I
>> don't intend to try to understand all the internals of site specific
>> URLs. I will only concern myself with (a) the semantics defined
>> for the specific URI scheme, or (b) knowledge defined about the
>> specific resource based on its otherwise opaque URI. (note that
>> URI class taxonomies are a disjunct issue entirely)
>> Thus if we are to capture in the URI itself whether a given resource
>> is or is not web-accessible, it must be done with the URI scheme.
>> That's it. What is within the scope of the host domain is not
>> interesting or useful with regards to global architecture (and
>> specifically should not be).
>>>> This seems to conflict with your earlier expressed opinion that the URI
>>>> should not reflect itself whether the resource is or is not "on the web"
>>> Er, no:  what I said was:
>>> [[
>>> (By which, I mean that I don't accept them as universal proposals:  I have
>>> no argument with their use as a convenient mechanism by you or any other
>>> developers. ...
>>> ]]
>>> I might have added "domain owners".
>> Fair enough. Though what if you had a means to expose a portion
>> of the semantics of a URI scheme which would apply to all instances
>> of that scheme, and do so globally, and in RDF, such that any
>> application could obtain that specification and use it to
>> interpret any instance of that URI scheme.
>> Then, it would not be proprietary, but open and ultimately extensible.
>> I.e, just as folks publish DTDs, XML Schemas, RDF Schemas, etc.
>> to expose the structure and semantics of content models, so
>> one could publish the semantics of a URI scheme that would allow
>> all applications to interpret URIs of that scheme consistently,
>> yet not have internal native knowledge about the scheme itself.
>> So I can, eg. define in RDF that URIs of the scheme voc: denote
>> non-web accessible resources, and any application that is presented
>> by such a URI then knows that it is meaningless to try to dereference
>> that URI. All that is required is a standardized ontology for
>> expressing a basic level of semantics about URI schemes useful for
>> most web agents needs when dealing with interpretation of URIs.
>> On the other hand, in the case of http: URIs which denote non-web
>> accessible resources, such knowledge would need to be defined for
>> each and every instance, which is a huge maintenance burden. Some
>> may prefer or require that level of resolution, but I think most
>> folks will prefer to enjoy the economy of URI scheme-wide semantics.
>> Still, having metadata specific response codes and methods would
>> work in either case. How the server determines the accessibility
>> of a resource remains open. It could be based on URI scheme or
>> per-resource knowledge.
>> Which method one chooses depends on the nature of the resource
>> and the abilities/needs of the creator.
>> Rather than 100s or 1000s of sites all employing their own
>> proprietary URI tricks to reflect whether the denoted resource
>> is or is not web accessible, wouldn't it be better to (a) use
>> a smaller set of standardized URI schemes to reflect such
>> distinctions and (b) express such semantics for those schemes
>> in RDF so applications need not maintain such knowledge natively?
>> After all, your approach suggests we could forgo schemes such
>> as mailto: or ftp: in place of site specific syntactic conventions,
>> such as http://mailto.nokia.com/patrick_stickler, etc. because
>> the site owner has said somewhere what the nature of such
>> resources are.
>> There is a clear tradition of distinguishing the accessibility
>> characteristics of URIs based on the URI scheme, so why not also
>> the non-accessibility characteristics? 'http:' means resolvable
>> via HTTP. 'voc:' means not ever resolvable or accessible. Simple,
>> clear, concise, consistent, and (ideally) standardized.
>> Eh?
>> Regards,
>> Patrick
>> --
>> Patrick Stickler              Phone: +358 50 483 9453
>> Senior Research Scientist     Fax:   +358 7180 35409
>> Nokia Research Center         Email: patrick.stickler@nokia.com
> -------------------
> Graham Klyne
> <GK@NineByNine.org>

Patrick Stickler              Phone: +358 50 483 9453
Senior Research Scientist     Fax:   +358 7180 35409
Nokia Research Center         Email: patrick.stickler@nokia.com
Received on Friday, 31 May 2002 08:42:56 UTC

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