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RE: network endpoints

From: Booth, David (HP Software - Boston) <dbooth@hp.com>
Date: Mon, 28 Apr 2008 05:51:10 +0000
To: Jonathan Rees <jar@creativecommons.org>, "public-awwsw@w3.org" <public-awwsw@w3.org>
Message-ID: <184112FE564ADF4F8F9C3FA01AE50009FCF226514D@G1W0486.americas.hpqcorp.net>

I'm just starting to catch up on this discussion after being away.

I do *not* think we should introduce the term "endpoint" or "network" into this discussion on the definition of awww:InformationResource at this point, because I think we are discussing the concepts at a level of abstrations that would be inappropriate for those terms.  The definition of awww:InformationResource (IR) that I proposed that is relevant to the current level of discussion was:
http://dbooth.org/2006/identity/#propdefir

        "a function from time and requests to representations"

An IR is thus a function f with two parameters:

  f: Time x Request --> Representation

The Request parameter includes things like language and mime preferences, request URI(!) and cookies.  On the other hand, the function Roy describes, which I'll call fRoy, and the model diagrammed at
http://sw.neurocommons.org/2008/inforesource.pdf
have only one parameter: time.  But note also that Roy's function does not go directly to representations, it goes to representation *sets*, so in essence I think Roy has pushed the Request input into the function result.  I.e., Roy's function fRoy can be viewed as a "curried"
http://en.wikipedia.org/wiki/Currying
form of my function f:

  fRoy: Time --> (Request --> Representation)

The main problem with the diagram at
http://sw.neurocommons.org/2008/inforesource.pdf
is that any "dereference" function needs *both* Time and Request parameters, because the resulting Representation may depend on both.  Also, I don't see the need for ValueCloud.



David Booth, Ph.D.
HP Software
+1 617 629 8881 office  |  dbooth@hp.com
http://www.hp.com/go/software

Opinions expressed herein are those of the author and do not represent the official views of HP unless explicitly stated otherwise.


> -----Original Message-----
> From: public-awwsw-request@w3.org
> [mailto:public-awwsw-request@w3.org] On Behalf Of Jonathan Rees
> Sent: Wednesday, April 16, 2008 9:29 AM
> To: public-awwsw@w3.org
> Subject: network endpoints
>
>
> One thing I would like to add to my diagram: A box for "network
> endpoint" with the meaning of a real-world source of
> awww:representations (e.g. a "web page" operationally defined by the
> process of sending an HTTP request specifying a particular resource-
> name string to a particular server, using the Internet, and so on).
> This is an interesting class of things that David Booth has
> articulated on a number of occasions. Tim and others have clearly
> said that these things are *not* IRs. I think it's more useful to say
> *how* endpoints relate to the intended information resources /
> denotations than to just say that they're not information resources.
>
> "Endpoint" would be placed near "value cloud" in the diagram and
> would be related to "value" by a relationship "responds to 200
> with ... (at time t)" and to "information resource" by another
> relationship that's analogous to "faithful to" i.e. for all time t
> any value delivered is a kr-representation of the state of the
> information resource.
>
> An "endpoint" could also be related to a "value cloud" via
> composition of relationships, but that would probably be clutter.
>
> Once all of these separate entities are defined we can start to talk
> about the relationships and invariants between them - e.g. does every
> endpoint have an associated IR? Are there endpoints whose URIs do not
> denote information resources? Are there endpoints for which the URI
> denotes an information resources but that is not faithful to that IR?
> For me it is this kind of question (not necessarily these particular
> ones) that will be useful in cracking the question of web semantics.
>
> None of this is to say I understand as well as Tim does what things
> can be "information resources" and what things can't... but I'm very
> happy to know that the URI does *not* generally denote the value
> cloud and that the value cloud isn't even part of or determined by
> the information resource. (Constrained, yes, but not determined.)
>
> I'll make the change in a day or two or three if I hear no outcry.
>
> Jonathan
>
> On Apr 15, 2008, at 8:34 PM, Jonathan Rees wrote:
>
> > Revised diagram based on this morning's meeting is here:
> >
> > http://sw.neurocommons.org/2008/inforesource.pdf
> >
> > (N.b. that's PDF, not PNG.)
> >
> > I've renamed 'abstract document' to 'information resource' since
> > the consensus was that they're the same.
> > The main reason to include the 'value cloud' in the diagram is to
> > help me understand how 'information resource' relates to Fielding's
> > formal definition of 'resource'.
> >
> > Let me know how you like it.
> >
> > Jonathan
> >
> >>
> >> http://sw.neurocommons.org/2008/inforesource.png
> >>
> >> which I will not take the time to prettify now (I don't know why
> >> the background is gray)
> >>
>
>
>
Received on Monday, 28 April 2008 05:52:14 GMT

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