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RE: 506 definition of structure

From: John M Slatin <john_slatin@austin.utexas.edu>
Date: Fri, 4 Jun 2004 09:37:17 -0500
Message-ID: <C46A1118E0262B47BD5C202DA2490D1A0183B140@MAIL02.austin.utexas.edu>
To: "Gregg Vanderheiden" <gv@trace.wisc.edu>, <w3c-wai-gl@w3.org>
The current wording of 1.3 says:
<current>
Ensure that information, functionality, and structure are separable from
presentation.
</current>
 
I've never been quite comfortable with the idea that structure can be
"separated" from information, and a recent exchange about the use of CSS
to provide content complicates it still more.  So let me try to say what
I think we *mean* here, and if I get it right then we can try to come up
with a clear statement that will work as a guideline.
 
The proposed definition of structure says that structure includes all
the parts of a Web resource and the way it is organized.  The goal of
1.3, as I understand it, is to ensure that all the parts of the
resource, including information about the way the resource is organized
and the things that the resource may do (its functionality), are
available to the user even when the way that resource looks or sounds
changes.  The changes might be caused by a user substituting his or her
style sheet for the author's, or by switching to an alternate style
sheet supplied by the author, or by using a user agent the author had
never heard of...
 
So it's not that these things "are separable from presentation": we're
really saying that the presentation must always include all the parts of
the resource, including functionality and structure.
 
John
 
 
"Good design is accessible design." 
Please note our new name and URL!
John Slatin, Ph.D.
Director, Accessibility Institute
University of Texas at Austin
FAC 248C
1 University Station G9600
Austin, TX 78712
ph 512-495-4288, f 512-495-4524
email jslatin@mail.utexas.edu
web http://www.utexas.edu/research/accessibility/
<http://www.utexas.edu/research/accessibility/> 


 

-----Original Message-----
From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On
Behalf Of Gregg Vanderheiden
Sent: Friday, June 04, 2004 8:58 am
To: w3c-wai-gl@w3.org
Subject: FW: 506 definition of structure



 Sorry John

 

Let me put it this way.

 

We say that authors must      separate information and structure from
presentation 

 

If structure is information then   that is kind of like saying
women and people.   

 

See my problem? 

 

Gregg

 

PS very interesting discourse below. 

 

 

________________________________

From: John M Slatin [mailto:john_slatin@austin.utexas.edu] 
Sent: Friday, June 04, 2004 8:26 AM
To: Gregg Vanderheiden
Subject: RE: 506 definition of structure

 

Gregg asks: "If text is structure what is information?"

 

John responds: It depends (what did you think I'd say? <grin>) And it
depends in part on what level of abstraction you're talking about.

 

What humans perceive as "information" doesn't exist in the abstract: it
is embodied in some form, some medium. Information may exist in the form
of text; it may exist in the form of graphics; it may be embodied in a
mathetmatical equation, a chemical formula, an animation generated by a
simulation, a video, etc. If a given human already knows the material in
question, she or he doesn't perceive it as information, though it may
count as information to the person sitting at the next desk. Information
*has* structure, and structure is information.  In our context, the
markup that create structure is information about the shape of the
information that a given document makes available.

 

 

Gregory Bateson says information is news of difference that makes a
difference.  From this standpoint, a chameleon is always trying *not* to
become information-- it wants (biologically speaking) to be
indistinguishable from surrounding context.  If the context changes
faster than the chameleon's skin can respond, it becomes information,
and instantly vulnerable to predators to whom the difference makes a
difference.

 

The self-organizing behavior of complex adaptive systems (like humans or
the Web) depends on a given system's ability to convert what information
theory would call "noise" (meaningless stuff coming in from outside)
into information *about the system itself*; the system then uses that
information to reorganize itself at a higher level of complexity.  The
Web was exactly such a phenomenon to the whole IT industry, and new
technologies for producing and rendering Web content force the same
kinds of reorganization-- hence our current effort to rewrite the
accessibility guidelines at a higher level of complexity that takes
account of all the technologies that are now used to produce Web
content.  Our guidelines will beomce another rock in the pond, etc, etc.

 

But the proposed definition doesn't say "text *is* structure."  It says
that text is one of the types of material that may be included in a Web
resource.  As far as I know, though, for all Web resources that have
source documents that employ markup languages (HTML, XML, SVG, etc.), it
might be literally correct to say "Text is structure" because everything
in the source document *is* text.  And if you go farther down the ladder
of abstraction even complex graphics and multimedia materials that are
merely *referred* to in the source document reduce to strings of ones
and zeroes, which can be represented in textual form.  So it's text all
the way down, or almost all the way down.

 

John

"Good design is accessible design." 
Please note our new name and URL!
John Slatin, Ph.D.
Director, Accessibility Institute
University of Texas at Austin
FAC 248C
1 University Station G9600
Austin, TX 78712
ph 512-495-4288, f 512-495-4524
email jslatin@mail.utexas.edu
web http://www.utexas.edu/research/accessibility/
<http://www.utexas.edu/research/accessibility/> 

 

-----Original Message-----
From: Gregg Vanderheiden [mailto:gv@trace.wisc.edu] 
Sent: Friday, June 04, 2004 12:05 am
To: John M Slatin
Subject: RE: 506 definition of structure

Hmmm

 

John?  If text is structure  what is information?

 

Gregg

 

 

________________________________

From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On
Behalf Of John M Slatin
Sent: Wednesday, June 02, 2004 10:15 AM
To: w3c-wai-gl@w3.org
Subject: 506 definition of structure

 

At the 27 May telecon, Jason and I took an action item to work on the
definition of structure.  The definition appears below.  Note: it is
common practice for dictionary definitions to include examples that
illustrate how the term is used in practice.  In this spirit, the
proposed definition refers to specific technologies (HTML, SVG, and
MathML) that make it possible to indicate structural aspects of
different kinds of content. We believe that it's clear from context that
using these examples does not create an implicit requirement that SVG is
the required format for all graphics or that MathML is the required
format for mathematical expressions.

 

Additional note: one of our goals was to bring this definition into
alignment with our commitment to plain language. The definition as a
whole receives a Flesch Reading Ease measure of 42.4 and a Flesh-Kinkaid
Grade Level of 10.0 (which corresponds to the beginning of the second
year of high school in the US). This is actually at the high end of the
scale-- according to Canada's Northwest Literacy  Council, a grade level
of 10+ is appropriate  if the document contains specialized technical
information and the audience is familiar with the topic and has good
literacy skills.  However, the same group recommends a grade level of
7-9 for material intended for the general public that contains new terms
and concepts or specialized subject matter. (Northwest Territories
Literacy Council. A plain language audit tool.  Available at
http://www.nwt.literacy.ca/plainlng/auditool/cover.htm. The specific
material about readability is at
http://www.nwt.literacy.ca/plainlng/auditool/8.htm.) 

 

<proposed definition>

Structure

Structure includes all the parts of a Web resource and the way they are
organized. 

 

The parts of a Web resource may include text, graphics, mathematical
equations, multimedia, etc. Some parts may contain other parts or create
relationships between two or more parts.     

 

Some relationships are hierarchical. Examples include sections and
sub-sections of HTML documents, where each section or sub-section begins
with a title that is marked as an HTML heading.  The material in each
section is logically related to the heading. The headings show the
logical organization of the document.

 

Some relationships are not hierarchical. Examples include links between
two parts of the same document or between two documents. 

 

Mathematical expressions also have structure.  It is possible to show
this structure.  For example, MathML can show the order in which
calculations should be performed.    

 

Graphics may also have structure. Examples include flowcharts, diagrams,
maps, and other complex images. SVG makes it possible to identify the
structure of graphics.

 

User agents may make the structure of Web resources evident to the user.

 

</proposed definition>


"Good design is accessible design." 
Please note our new name and URL!
John Slatin, Ph.D.
Director, Accessibility Institute
University of Texas at Austin
FAC 248C
1 University Station G9600
Austin, TX 78712
ph 512-495-4288, f 512-495-4524
email jslatin@mail.utexas.edu
web http://www.utexas.edu/research/accessibility/
<http://www.utexas.edu/research/accessibility/> 

 

 
Received on Friday, 4 June 2004 10:37:22 GMT

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