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RE: BIG ISSUE -- re Delivery Units

From: Gregg Vanderheiden <gv@trace.wisc.edu>
Date: Wed, 8 Feb 2006 22:44:52 -0600
To: <w3c-wai-gl@w3.org>
Message-ID: <00c401c62d33$939eaeb0$ee8cfea9@NC6000BAK>
The term Web Page (which I would dearly love to use) isn't sufficient
because of example 2 in the definition.   We need to cover that too --- and
we don't if we use web page.


The goal is to replace    delivery unit   throughout with      Web Unit.
So the D U term in content would be replaced as well. 




 -- ------------------------------ 
Gregg C Vanderheiden Ph.D. 
Professor - Ind. Engr. & BioMed Engr.
Director - Trace R & D Center 
University of Wisconsin-Madison 




From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On Behalf
Of Bailey, Bruce
Sent: Wednesday, February 08, 2006 8:22 PM
To: w3c-wai-gl@w3.org
Subject: FW: BIG ISSUE -- re Delivery Units

I believe the opacity of the term "delivery unit" is actually a bigger
problem than the fact that the definition from Glossary of Terms for Device
Independence is not correct for what is meant.  Web Unit has this same

The new definition is very good, and including "e.g. page" is extremely
helpful.  I suspect it might be a productive exercise to articulate exactly
why the term "page" is not satisfactory.

Most of the SC use the term "content" which is elegant.  Some of the SC
could benefit from a similar treatment.  For example:

4.1.1: Content can be parsed unambiguously and the relationships in the
resulting data structure are also unambiguous.

There definitely are SC where this approach is problematic:

2.4.4: Content has titles.

The glossary currently uses delivery unit in the definition of content.  Can
this be avoided?  I don't thing the current definition for content makes it
clear that content can be single files (like PDF or Word) and web

The concept of scope, and that conformance claims are for all scoped
content, might help clarify what is meant by "content".

Other terms resulting from some brainstorming with a colleague:  browser
page, document, web document, document or file, web document or web

-----Original Message-----
From:   w3c-wai-gl-request@w3.org on behalf of Gregg Vanderheiden
Sent:   Wed 2/8/2006 4:23 PM
To:     w3c-wai-gl@w3.org
Subject:        BIG ISSUE -- re Delivery Units

Currently we have a number of success criteria that talk about delivery
units.    However, the delivery unit is anything you can get with an HTTP

(All of the sc that the term delivery unit is used in our guidelines are
listed at the bottom of this email.)

So a page with all of its images is a D U.  But each image by itself is also
a D U. 

The problem is

1.      the images don't pass our guidelines
2.      if you make any kind of claim for your site (or any URI pattern) it
would include the URI's for the images etc (unless you stored the images off
in some remote location)

This is not what we intend.    After looking at this for awhile Ben and John
and I are suggesting that perhaps we focus on the delivery unit you get from
a user request and not the subsequent delivery units that are fetched as
part of it.   To do this we would need to define a new entity.

John, Ben and I have discussed and examined this and are proposing a new
term "Web Unit" that would replace all occurrences of Delivery Unit in the
guidelines and related documents.

Take a look.  Think hard.  And then send your comments. 

Web Unit (e.g. Page)

    A collection of information, consisting of one or more resources,
intended to be rendered together, and identified by a single Uniform
Resource Identifier (URLs etc.).    

NOTE:    This term was adapted from the definition of web page in Device
Independent group and Web Characterization Terminology & Definitions Sheet
except concept of simultaneity was removed to allow the term to cover
interactive multimedia content.

Example 1:  A web page including all embedded images and media.

Example 2:  An interactive movie like shopping environment where the user
navigates about and activates products to have them demonstrated, and moves
them to cart to buy them.

Here are all the occurrences of Delivery Unit.

2.2.2  [P/D] Content does not blink
<http://www.w3.org/WAI/GL/WCAG20/appendixA.html#blinksdef>  for more than 3
seconds, or a method is available to stop any blinking content in the
delivery unit
<http://www.w3.org/WAI/GL/WCAG20/appendixA.html#deliveryunitdef> . [How
tml#time-limits-blink>  to meet 2.2.2]

2.4.2 [P] More than one way is available to locate content within a set of
delivery <http://www.w3.org/WAI/GL/WCAG20/appendixA.html#deliveryunitdef>
units where content is not the result of, or a step in, a process or task.
tml#navigation-mechanisms-mult-loc>  to meet 2.4.2]

2.4.3 [P] Blocks of content that are repeated on multiple perceivable units
<http://www.w3.org/WAI/GL/WCAG20/appendixA.html#perceivableunitdef>  [NEEDS
TO BE CHANGED TO DU]  are implemented so that they can be bypassed. [How
tml#navigation-mechanisms-skip>  to meet 2.4.3]

2.4.4 [P] Delivery
<http://www.w3.org/WAI/GL/WCAG20/appendixA.html#deliveryunitdef>  units have
titles. [How
tml#navigation-mechanisms-title>  to meet 2.4.4]

2.4.5 [P] Each programmatic reference
to another delivery
<http://www.w3.org/WAI/GL/WCAG20/appendixA.html#deliveryunitdef>  unit or to
another location in the same delivery unit, is associated with text
describing the destination. [How
tml#navigation-mechanisms-refs>  to meet 2.4.5]

2.4.7 [P] When a delivery
<http://www.w3.org/WAI/GL/WCAG20/appendixA.html#deliveryunitdef>  unit is
navigated sequentially, elements receive focus in an order that follows
relationships and sequences in the content. [How
tml#navigation-mechanisms-focus>  to meet 2.4.7]

2.4.8 [P] Information about the user's location within a set of delivery
<http://www.w3.org/WAI/GL/WCAG20/appendixA.html#deliveryunitdef>  units is
available. [How
tml#navigation-mechanisms-location>  to meet 2.4.8]

3.1.1 [P] The primary natural
<http://www.w3.org/WAI/GL/WCAG20/appendixA.html#natural-langdef>  language
or languages of the delivery unit can be programmatically determined
f> . [How
tml#meaning-doc-lang-id>  to meet 3.1.1]

3.2.3 [P] Navigational mechanisms that are repeated on multiple delivery
<http://www.w3.org/WAI/GL/WCAG20/appendixA.html#deliveryunitdef>  units
within a set of delivery units occur in the same
<http://www.w3.org/WAI/GL/WCAG20/appendixA.html#samerelorderdef>  relative
order each time they are repeated unless a change is initiated by the user.
tml#consistent-behavior-consistent-locations>  to meet 3.2.3]

3.2.4 [P] Components that have the same functionality
<http://www.w3.org/WAI/GL/WCAG20/appendixA.html#samefunctionalitydef>  in
multiple delivery
<http://www.w3.org/WAI/GL/WCAG20/appendixA.html#deliveryunitdef>  units
within a set of delivery units are identified consistently. [How
tml#consistent-behavior-consistent-functionality>  to meet 3.2.4]

4.1.1 [P/D] Delivery
<http://www.w3.org/WAI/GL/WCAG20/appendixA.html#deliveryunitdef>  units can
be parsed <http://www.w3.org/WAI/GL/WCAG20/appendixA.html#parsed-unambigdef>
unambiguously and the relationships in the resulting data structure are also
unambiguous. [How
tml#ensure-compat-parses>  to meet 4.1.1]
Received on Thursday, 9 February 2006 04:45:10 UTC

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