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Cross-set Introduction work

From: Murray Maloney <murray@muzmo.com>
Date: Wed, 04 Oct 2006 11:07:10 -0400
Message-Id: <5.1.1.6.2.20061004110051.00abcf08@mail.muzmo.com>
To: public-grddl-wg <public-grddl-wg@w3.org>

Here is what I had proposed as a cross-set introduction....

Each Introduction would end with a customized section that describes
that WD and provides pointers to the other two WDs in the set.

I deally, I would like to integrate some of the content from the existing Intro
to the Primer.

Unfortunately, Dan ran out of time and energy to complete the edits and
could not get a hold of the other editors. So, I am holding fire until I get
a go ahead to complete work on the Introduction.

=============================================================
<div>

<h2 id="intro"><span class="gen">1.</span> Introduction: Data and 
Documents</h2>

<p>There are many dialects in practice among  the many XML documents on the 
web.
There are dialects of XHTML, XML and RDF that are used to represent 
everything from
poetry to prose, purchase orders to invoices, spreadsheets to databases, 
schemas to scripts,
and linked lists to ontologies. Some are more formally defined and others 
exhibit more
loosely-couple semantics. Recently, two progressive encoding techniques 
have emerged
to overlay additional semantics onto valid XHTML documents: RDF-a and 
microformats
offer simple, open data formats built upon existing and widely adopted 
standards.
</p>

<p>While this breadth of expression is quite liberating, inspiring new 
dialects to codify both common and customized meanings, it can prove to be 
a barrier to understanding across different domains or fields. How, for 
example, does software discover the author of a poem, a
spreadsheet and an ontology? And how can software determine whether
authors of each are in fact the same person?</p>

<p>Any number of those XML documents on the web may contain data
whose value would increase dramatically if they were accessible to systems
which might not directly support such a wide variety of dialects but which
do support RDF.</p>

<p>The Resource Description Framework<a href="#RDFC04">[RDFC04]</a>
provides a standard for making statements about resources in the form
of a subject-predicate-object expression. One way to represent the
fact "<I>The Stand<I>'s author is Stephen King" in RDF would be as a triple
whose subject is "The Stand," whose predicate is "has the author," and
whose object is "Stephen King," The predicate, "has the author"
expresses a relationship between the subject (The Stand) and the object
(Stephen King).  Using URIs to uniquely identify the book, the author and
even the relationship would facilitate software design because not
everyone knows Stephen King or even spells his name consistently.
</p>

<p>RDF includes an XML concrete syntax and an abstract
syntax.  Software tools that use the Resource Description Framework
naturally work with documents whose data is encoded using
RDF/XML.
</p>

<p>GRDDL is a mechanism for <b>G</b>leaning <b>R</b>esource
<b>D</b>escriptions from <b>D</b>ialects of <b>L</b>anguages; that is,
for extracting RDF data from XML documents by way of transformation
algorithms, typically represented in XSLT.</p>

<p><em class="ed">@@TODO: consider a different hello-world
example, synced with primer/use cases.</em></p>

<p>For example, Dublin Core meta-data can be written in an HTML
dialect<a href="#RFC2731">[RFC2731]</a> that has a clear
correspondence to an encoding in RDF/XML<a
href="#DCRDF">[DCRDF]</a>. The following HTML and RDF excerpts
illustrate the correspondence:</p>

<pre class="example">&lt;html xmlns="http://www.w3.org/1999/xhtml"&gt;
   &lt;head&gt;
     &lt;title&gt;Some Document&lt;/title&gt;

     &lt;meta name="DC.Subject"
        content="ADAM; Simple Search; Index+; prototype" /&gt;
     ...
   &lt;/head&gt;
   ...
&lt;/html&gt;</pre>


<pre class="example">&lt;rdf:RDF
   xmlns:dc="http://purl.org/dc/elements/1.1/"
   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
   &gt;
   &lt;rdf:Description rdf:about=""&gt;

     &lt;dc:subject&gt;ADAM; Simple Search; Index+; 
prototype&lt;/dc:subject&gt;
   &lt;/rdf:Description&gt;
&lt;/rdf:RDF&gt;</pre>

<p>The transformation algorithm used to is expressed in an
XSLT transformation, <a
href="http://www.w3.org/2000/06/dc-extract/dc-extract.xsl">dc-extract.xsl</a>:</p>

</div>
Received on Wednesday, 4 October 2006 15:24:39 GMT

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