W3C home > Mailing lists > Public > public-awwsw@w3.org > February 2011

Re: Problem definition

From: Nathan <nathan@webr3.org>
Date: Thu, 17 Feb 2011 20:25:00 +0000
Message-ID: <4D5D841C.5030807@webr3.org>
To: AWWSW TF <public-awwsw@w3.org>
CC: Jonathan Rees <jar@creativecommons.org>

Analysis of URI Architectures, working from:
   http://neurocommons.org/page/WebURIArchitectures


Null hypothesis
=======================

   [
     a :Representation ;
     :wasRetrievedFrom [ a :NetworkResource ; address "http://..." ]
   ]

exactly matches the uniform interface of HTTP, network accessible 
resources are not identified by URIs, neither are representations - 
because link between "resource" (rest/http speak) is 1-* with network 
accessible resources, and link between resources and representations is 
1-* - even when the "real" mappings are both 1-1,you cannot prove or 
tell this to be true.

unclear what one would use the URI to refer to, but given the presence 
of those statements one could set the domain/range of common properties 
like "stylesheet" to be :Representation and thus disambiguate them 
(change the subject to be the blank node identifier of the representation).

null hypothesis clears up one level of the web, such that <u> is not 
used to refer to network accessible resources or representations, but 
still leaves a partial chimera state where <u> can refer to the 
"document" or "primary topic"/ "any thing".


TimBL / httpRange-14 / Cool URIs for Semweb
===========================================

   <u> a :InformationResource .

this is the current (perceived) status quo, but InformationResource is 
unclear and often used to refer to representations, documents, and 
primary topics (where primary topic can itself be considered an 
information resource)

has negative side effects on community of not being understood, and 
network of requiring 2 GETs per URI (+ potential knock on effects on 
provenance etc) and people using the wrong URI to refer to the thing 
named (the 303'd to one)


Primary topic
=============

   <u> a :Thing .

this design does remove the chimera state, by saying that <u> always 
names a thing, but this means that <u> doesn't refer to the document and 
in reality people still use <u> to refer to the :Document (and 
representation and network accessible resource) - so fails.


What the page says
==================

   <u> a :Thing

this design does remove the chimera state, by saying that <u> always 
names a thing, but this means that <u> doesn't refer to the document and 
in reality people still use <u> to refer to the :Document (and 
representation and network accessible resource) - so fails.

"what the page says" and "primary topic" are the same, just primary 
topic has the perspective that a page/graph only primarily describes a 
single thing.


Chimera theory
===============

   <u> a :Representation, :NetworkResource, :Thing, :Document .

this is the current reality, and what we want to get away from!


Linked data URIs refer to information resources
================================================

I believe the text written about this to be wrong, and understand it to 
mean that the dereferencable absolute-URI part of an http URI refers to 
information resources, indeed this is consistent with the way Timbl 
talks about the web and publishes data

   <http://www.w3.org/People/Berners-Lee/card> a :Document .
   <http://www.w3.org/People/Berners-Lee/card#i> a :Person .

This approach, the one Tim uses (fragments for things) is the only 
approach that currently removes the chimera state between the web of 
data and the web of documents, however the chimera state between web of 
documents and representations still exists when using RDFa and URIs for 
Documents whenever representation metadata is present.


Again, not mentioning anything about what the "goal" of all of this is, 
it's certainly to remove the chimera state from the web of data, to get 
rid of httpRange-14 -or- constrain what IR means in order to solve the 
cc:license problem. Could probably write up the goal(s) quite easily and 
use them to check mark solutions.

Best,

Nathan

Nathan wrote:
> resend (sent from wrong address previously)
> 
> Hi,
> 
> Tried to write up the problem, as I see it (keeping away from solutions
> at the minute).
> 
> Agree with the following summary(?):
> 
> Competing uses of dereferenceable absolute http scheme URIs:
> 
> 1: network accessible resource
>    - uri as an address for some process on the web
> 2: representation
>    - uri as referring to a specific content+content-meta
>      (fixed resource/simple IR)
> 3: document / "source of information"
>    - not well defined, typically "web of documents"
> 4: primary topic of a document / "source of information"
>    - when a document is primarily about one thing
> 5: any thing
>    - any single thing, whatever a name is commonly used to refer to
> 
> 
> Ideal Layers of the Web:
> 
>                            _ network accessible resources
>   Network / Computers ----|_
>          |                   representations
>     [hidden by]
>          |                 _ sources of information
>    Web of Documents ------|_
>          |                   documents
>     [hidden by]
>          |                 _ primary topic of a document
>     Web Of Data ----------|_
>                              any thing
> 
> 
> Proof of each URI use:
> 
> 1: network accessible resource
>    <link rel="pingback" href="/pinger" />
>    (treats @href like an address)
> 
> 2: representation
>    in a document you GET from <u>
>    <link rel="stylesheet" href="/styles.css" />
>    creates triple <u> xhv:stylesheet "<u>/styles.css" in RDFa
>    (uses <u> to identify representation)
> 
> 3: document / "source of information"
>    <a href="/foo.html">foo</a>
> 
> 4: primary topic
>    <meta property="og:title" content="blog post title" />
> 
> 5: any thing
>    have you met <a href="<u>">my mum</a> ?
>    <http://xmlns.com/foaf/0.1/name>
> 
> 
> chimera theory:
> 
>   "URI refers to a 'chimera' entity that has some of the properties of
>    the page and some of the properties of either its primary topic or
>    the entity named on the page by the URI."
> 
> is chimera theory current reality? yes
>   many pages, like a doc with open graph, uses the same URI to refer to:
>    - network accessible document
>    - representation
>    - document
>    - primary topic
>    - any thing (usually also the primary topic "blog post" or "my mum")
> 
> problem:
> web of data / sem web requires one name to be used to refer to one thing.
> 
> httpRange-14:
> there exists a class of information resources, and dereferencable http
> scheme URIs are used to refer to these
> 
> httpRange-14 problem, the rel cc:license problem:
> "information resource" is loosely defined, such that when a GET pulls
> back HTML which contains a "blog post", things from all three layers are
> classed as an information resource
>   - representation
>   - the document
>   - primary topic, the blog post.
> does dc:created refer to representation, to the document, or the blog
> post? does cc:license apply to the representation, the document or the
> blog post?
> 
> does httpRange-14 resolution remove chimera state of the web?
>   no.
> 
> potential next steps:
>  - remove chimera state from web of data
>     (possible B.C. breaks)
>  - live with chimera state and focus on disambiguation
>     (requires interpretation of statements, only graphs can be
> interpreted to the level required to disambiguate chimera state)
> 
> Best,
> 
> Nathan
> 
> 
> 
> 
Received on Thursday, 17 February 2011 20:26:07 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Thursday, 17 February 2011 20:26:07 GMT