This document is prepared by the
Please refer to "
This is a draft document and may be updated, replaced, or obsolete by other documents at any time. It is inappropriate to use W3C Working Drafts as reference material or to cite them as other than "work in progress". A list of
The Working Group welcomes comments on this document at
Patent disclosures relevant to this specification may be found on the WCAG Working Group's
This document has been produced as part of the W3C
This document describes techniques for authoring accessible content using RDF
and metadata. This is the first Working Draft associated with the latest Web Content Accessibility Guidelines 2.0 Working Draft.
This document is intended to help authors of Web content who wish to claim conformance to "Web Content Accessibility Guidelines 2.0"
This document will be part of a series of documents published by the W3C Web Accessibility Initiative (WAI) to support WCAG 2.0.
Over the past several years there has been a significant increase in awareness of the need for Web accessibility and development of policies relating to Web accessibility in Europe. Techniques for implementations have been standardized and benchmark guidelines (Web Content Accessibility Guidelines - or WCAG), have been accepted. However, with the evolution of the Semantic Web and RDF, there is an additional ability and necessity to provide better implementations, interfaces and techniques for accessibility principals and guidelines.
Semantic Web and RDF technologies creates the robust support needed in traditionally problematic areas such as adequate access for the cognitively disabled. It also solves other crucial accessibility problems, which are emerging as XML usage becomes increasingly prevalent.
Annotation base accessibility usage could solve accessibility problems in the following situations:
Simplified, annotated or multimedia content required for accessibility for some, is inappropriate for other audiences. 2 For example: annotations can provide, titles, headers, summaries (non normative) , glossary references and links to background information
The original rendering is incapable of change, such as when web authors are unable to use simplified language.
There are a large amount of pages to be made accessible including legacy pages - Annotations work generically on a site and are constructed to apply to the whole site. A single annotation can address a violation that occurs on multiple pages, and will fix each occurrence of the accessibility violation. The site does not have to be pulled down and retrofitted, and many pages can be automatically repaired. Annotations can also be constructed to apply generically to any content that is based on the same template. The same annotation repairs multiple pages that are created by the same application and template.
XML schema can be annotated to increase accessibility usage, which could have an effect of an immeasurable number of documents based on that schema.
Multiple alternatives / conditional content in different medias can be provided. For instance, an auditory rendering of a visual aid might be more appropriate in some contexts than text.
User profiles can be attached to Web content and alternatives, so renderings can be optimized to the individual user.
User profiles can be attached to Web content and alternatives, so renderings can be optimized to the individual user.
As a secondary benefit, RDF Improves compatibility Knowledge-Based Services and the Semantic Web. In integrating accessibility and the semantic web, accessibility can be moved forward, paving the way for customized accessible searches and intelligent user agents with additional applications.
The Resource Description Framework (RDF ), is an XML based infrastructure that allows the capture, encoding, sharing, and reuse of structured metadata and semantic information. RDF does not provide syntax or a vocabularies for each resource description community, but provides the ability for communities to define and share terms. (ontologies)
This section describes some existing ontolgies and mechanisms that are usefully to to the accessibility community, for the capture and sharing of information that may help move accessibility forward.
Place holder - using Amaya - we can just get this from the Amaya page...
RDF statements and semantic web annotations are written using a language or syntax of the semantic web (an ontology).
Ultimately the use of RDF to achieve WCAG conformance is only valid if the user can easily access an accessible rendering of the original page. Hence there must be a free, publicly available engine where any end user or user agent can receive render the site accessibly for free. with out this the accessibility of the page can not be considered robust. Web technologies used must maximize the ability of the content to work with current and future accessibility technologies and user agents. Secondly care must be taken that all the accessibility features that you require through RDF are provided within the ontology.
The user needs to know how to access the accessibility fetchers. This can be done through an accessible link at the beginning of the original page. Clear instructions can also be used, but they run the risk of adding burden to the end user. If instructions are to be used they should be short step by step and quick to use. to use.
Once you have chosen and RDF language the web author need to fulfill all the accessibility requirements of ensuring that all content is perceivable, operatable, navigatable and understandable.
Examples of using; RDF for accessibility
The ontology in used in these examples have been developed by UB Access.
The page http://www.yadsarah.org.il/english/index.asp?id=95 was not compliant with WCAG 01.
However an RDF file with annotations with accessibility related annotation and equivalents was created. Users can now go to the Unbounded Access server and receive renderings of the page that are accessible and optimized to their needs.
<ul><li>see <a href="http://192.197.109.99/applications/yadsarahBasic">a basic accessible</a> SWAPView</li>
see <a href="http://192.197.109.99/applications/yadsarahTrueText">true text</a> SWAPView</li>
see <a href="http://192.197.109.99/applications/yadsarahpageMap">enhanced navigation</a> SWAPView</li>
The following examples demonstrate how one can construct an RDF file that render a page accessible.
The following examples demonstrate how one can construct an RDF file that render a page accessible.
case - using a header file
original page:
However it has in the header a reference to a RDF resource document
If you go to UB Access test server you can see SWAP take the resource , take
the RDF file and render an accessible page
Using this application anyone can make your own page, RDF file and go to
case - using a referencing file
This is an example where you can not add the header line into the inaccessible
page (maybe because you do not have access to the inaccessible source pages)
What you can do is make a separate file that links the resource and the resource
document. see
SWAP will render the linked to resources accessible It needs a separate pipeline
note: in this case the inaccessible page can be in invalid markup (like badly written html) only the file with the links needs to be in XML
This section describes ways to provide media equivalents using metadata.
In the following examples alternatives to media or image elements are provided using RDF
RDF :about="xpointer to an image" type="accessibilityAnnotation">
aural rendering
1.1.1
1.1
]]>
Alternates for Images - In the following examples a image is provided without a text equivalent. In a header file or header the RDF points to the image and associates textual alternates for the image. This example uses the SWAP ontology by UB Access
place holder: We are working on a document (with IBM and (hopefully)macromiedia ) to map interactivity
place holder: Using Amaya - Annotea associated alternatives. Note this allows third-party annotations of any Web Resource.
place holder: using time stamped RDF to annotate W3C multi media (like SMIL) to proved Sync multi media equivalents...Note I am talking to Bob Regan if we can do somthing with FLASH :)
place holder: image annotation, using SVG (need to ping Patrick Roth)
place holder: SVG Metadata Charles is working this out....
Alternates fro scripts - In the following examples scripts in a page do not have a usefull no scripts alterative associated. In a header file or header the RDF points to the script and associates XHTML alternates for the image. This example uses the SWAP ontology by UB Access
RDF -schema#">
6.3.17
6.3
]]>
Alternatives for frames. - An alternative for a frame set can be referenced using RDF . However a transcoding service can also be referenced. For example see the page http://ue.eu.int/newsroom/newmain.asp?LANG=1 Hear the frames are used inaccessible. Annotations can provide titles to the frames helping the user orientate themselves between framesets as required by WCAG 1.0. However non frames equivalents can also be references, and can be created automatically by transcoding. For example see http%3A//ue.eu.int/newsroom/newmain.asp%3FLANG%3D1 Has been automatically transcoded into a no frames rendering: See http://69.10.136.193/applications/convertToPDACompliant/http%3A//ue.eu.int/newsroom/newmain.asp%3FLANG%3D1
RDF -schema#">
6.3.17
6.3
]]>
Semantically described services The use of Semantically rich descriptions for services on the Web can include machine-processable information about alternative versions of a service that may be appropriate to a particular delivery context. This can allow searching for more accessible versions of a script or applet being used, or directing users directly to an alternative.
The techniques in this category demonstrate how to clarify text using metadata.
Ambiguous use of language creates problems with translation, misunderstandings and accessibility for cognitive disabilities.Translation to symbolic languages or simpler language for cognitive disabilities can not be automated. A controlled language restricts author's ability to stylize and express them-selves.
But..by referencing textual content, it's meaning becomes unambiguous, translatable and machine-readable without restricting the author's use of language.
In the following examples RDF is used to provide a link a phrase or word to a definition. This makes the text unambiguous.
In the following examples RDF is used to provide a link a document to a lexicon. This makes the text unambiguous, and easy to translate and simplify.
Note that this can be overridden by a word specific definition.
RDF :about="URI" type =ub:accessibilityAnnotation>< ub:lexicon >www.ubaccess.com/simplelexicon.xml
]]>
In the following examples RDF is used to provide a link a specific instance of phrase or word to a definition in an onsite glossary. This helps makes the text unambiguous or simpler.
Note that this would override a general reference to a lexicon
RDF :about="xpointer to text"type =ub:accessibilityAnnotation>< ub:lexicon >www.mysite.com/my glossary#this word
]]>
annotating the components of a VoiceXML application or a timed text track, to concepts or symbols...
What is consept code....
rely on a stable foundation of concepts with unique IDs referring to one or more Ontologies where the concepts are clearly defined – including their relations to other concepts. The parts are:
Concept Code Definitions (CCD) – which contains a plain list of all the concepts of the CCF
Base Reference Ontology (RO) – which contains the concepts of the CCD that have been derived from WordNet
Complementary Reference Ontology (CO) – that contains the concept of the CCD that is not found in WordNet.
CCF Bridge – which links the three parts of the CCF to each other, and all of them to external resources.
In the following examples RDF is used to provide a link to each word in a document to a concept....
I want a cup of coffee.
RDF
xml:xmlns ccf="http://www.wwaac.org/2003/10/ConceptCodingFramework-ns#"
>
RDF :about=”#xpointer(“I”)”>
RDF :resource=”scc:#CC-FIRST-PERSON-1”/>
RDF :resource=”&iso-bliss;14916”/>
RDF :about=”#xpointer(“want”)>
RDF :resource=”scc:#CC-WANT-2”/>
RDF :resource=”&iso-bliss;18035”/>
RDF :about=”#xpointer(“a”)>
RDF :resource=”scc:#CC-A-1”/>
RDF :resource=”&iso-bliss;12321”/>
RDF :about=”#xpointer(“cup”)>
RDF :resource=”scc:#CC-CUP-2”/>
RDF :resource=”&iso-bliss;13621”/>
RDF :about=”#xpointer(“of”)>
RDF :resource=”scc:#CC-OF-1”/>
RDF :resource=”&iso-bliss;13100”/>
RDF :about=”#xpointer(“coffee”)>
RDF :resource=”scc:#CC-COFFEE-1”/>
RDF :resource=”&iso-bliss;13373”/>
RDF >
]]>
The techniques show how to simplify text using metadata.
People with cognitive disabilities may unable to access important content as a result of the design chosen by website creators. The first problem in converting normal text to symbols is that there is simply too much of it. To be simplified in the most functional manner, a lot of text must be omitted. However, a user agent cannot distinguish the relative importance of sections of content. Importance also varies depending on the user's intentions when reading a document, as well as their actual capabilities. For example, legal footnotes and annotations are an important feature of many documents. But legal annotations are often not relevant when somebody is simply trying to understand the technical implications of a specification. In fact many proficient readers will simply skip over such material without bothering to try and understand the detail. To make an appropriate simplification for a dyslexic engineer trying to understand the technical implications, it is useful to remove the legal material as it avoids confusion and time wasted trying to understand something unnecessary. Annotations that explain or clarify terms however, should be included. In other words, the importance of any textual feature depends on the user profile. This varies from user-to-user, according to what he/she is doing, and according to each person's specific abilities.
An RDF vocabulary can an author to attach a level of importance to any section of web content. All accessibility annotations can have user profile information attached that states how important certain text is to each profile. For example some text is important content for any type of comprehension while some text is merely ornamentation intended to heighten the reading pleasure of the expected audience. The user can then adjust the amount of content rendered based on how relevant it is
An RDF vocabulary can an author to attach a level of importance to any section of web content. All accessibility annotations can have user profile information attached that states how important certain text is to each profile. For example some text is important content for any type of comprehension while some text is merely ornamentation intended to heighten the reading pleasure of the expected audience. The user can then adjust the amount of content rendered based on how relevant it is.
In this example a relevance of" 0" implies content is irrelevant to a given profile. A relevance of" 1" implies content is key information for a given profile.
This example shows how to provide alterative content to help summarize or simplified sections of web content.
RDF :about="some xpointer to obtuse legal paragraph" type ="ub:accessibilityAnnotation"> simplified
"mso-tab-count: 1"> 4.1
]]>
This example shows how to provide alterative content to summarize or simplify a word or phrase were ever it occurs in a web document.
RDF :about="xpointer to phase in the event of" type ="ub:accessibilityAnnotation"> simplified
4.1
The techniques in this category demonstrate how to add structure to sections of web content using metadata.
Place holder: Identifier types of content typically found in a page .
For example: Main menu Nav bar Main content Confidentiality information...
Ensure each have a valid URI. Web authors can then annotate documents as to the type of content each section is. Or even what type of page. (Extremely useful for assistive technologies and transcoding.)
The development of this may warent a taskforce
Use the
The
An RDF vocabulary can an author to attach a level of importance to any section of web content. All accessibility annotations can have user profile information attached that states how important certain text is to each profile. For example some text is important content for any type of comprehension while some text is merely ornamentation intended to heighten the reading pleasure of the expected audience. The user can then adjust the amount of content rendered based on how relevant it is.
In this example a relevance of" 0" implies content is irrelevant to a given profile. A relevance of" 1" implies content is key information for a given profile.
place holder - why add structure..
This allows an author to associate elements as belonging to a block of elements. These can be standard blocks (menu 1, menu 2, menu 3, menu 4,) or to an element that is a block owner like a table header). You can define a block owner using isBlock
Blocks can reference a know identifies of different block types
We can add hear URI for known blocks types: main menu, submenu, copy write info, main content....
We can also add types of content on another level- informative, pricing, ....
This example shows how to use the
Use the
Use the
The
NOTE:The
Use the
The
element for formatting effects such as indentation.
In the following examples RDF is used to provide a link a phrase or word to a summary and picture. This makes the text understandable.
:
RDF :about="some xpointer to obtuse legal paragraph" type ="ub:accessibilityAnnotation">
simplified
4.1
]]>
This section discusses the accessibility of tables and elements through annotations
Use the
Using the summary tital and caption properties in the UB access ontologie an RDF attribute allows additional meaning or context and can be applied to any element;including a data tablee.
An RDF vocabulary can an author to assosiate rows with headers
RDF -schema#">
5.1.1
5.1
]]>
An RDF vocabulary can an author to associate rows with headers
RDF :about="some xpointer to obtuse legal paragraph" type ="ub:accessibilityAnnotation"> simplified
"mso-tab-count: 1"> 4.1
]]>
Use the
Use the
An RDF vocabulary can an author to associate a table summary
RDF -schema#">
5.5.1
5.5
]]>
An RDF vocabulary can an author to associate rows with headers
RDF :about="some xpointer to obtuse legal paragraph" type ="ub:accessibilityAnnotation"> simplified
"mso-tab-count: 1"> 4.1
]]>
This example shows how to provide alterative content to summarize or simplify a word or phrase were ever it occurs in a web document.
RDF :about="xpointer to phase in the event of" type ="ub:accessibilityAnnotation"> simplified
4.1
This section discusses the accessibility of Forms and form elements through annotations
The WAIs XML Accessibility Guidelines - 1 October 2002 begins with the following problem statement:
“One area of concern with the advent of XML is that the freedom of design it brings has and can result in a loss of accessibility features, present today because of HTML's pervasive presence and widely available specification. For instance, one could design a new XML language that would make it much more difficult to create accessible documents, by not including in the element or attribute set a way to attach an alternate textual description for a photo:" With WCAG-RDF an author could provide alterative content to any valid XML document. The co - author s of the XML Accessibility Guidelines have bean instrumental in the putting together of the WCAG-RDF project as a potential and credible solution for these emerging accessibility problems.
Further many of the XML Accessibility Guidelines such as: Use the standard XML linking and pointing mechanism Provide semantic relationships to other schema where appropriate and possible. Could be supported best though RDF without restricting the language authors style. Beyond that an XML schema could be annotated to solve such accessibility issues for any derived document.
Use the
.
isSimilarToElement allows one to associate elements as being similar to other known elements. The content of an isSimilarToElement should be the URI to the definition of the known element The isSimilarToElement can also be used to annotate ILS annotations as similer to e difrent ILS annotation- for example a ClarifiedText annotation can also be literal, and a summary
]]>
Use the
from swad EU -(as is a lot of this...) Annotating elements of schemas which are new, obsolete or deprecated, or render sections of earlier specifications obsolete would allow for some automatic testing of this checkpoint.