Shameless Plug

• En route
  • From Land's End
  • To John O'Groats
  • Touring Scotland on the way
• Raising money for
  • Royal National Institute for the Blind
  • Wessex Heartbeat
  • http://endtoendblog.blogspot.com

Introduction

• The semantics of 'Life'
• Constraints on web page delivery
• Challenges for users with disabilities
• Challenges for small, mobile devices
• Semantics
  • Application Semantics
    • Unconstrained
    • Semantic Enrichment
  • User Interface Semantics
    • Semantically Rich Markup

Traditional Approaches

• Interpretation and reverse engineering
  • Assistive Technologies
  • Transcoders
• The curse of visual juxtaposition!
  • Author's assumptions
    • "They'll experience what I experience... won't they?"
  • Lack of structuring information
  • Proximity through layout and styling
  • Forms
• Heuristics
• Results can be good sometimes, but could be so much better

An Example

'New this Week' section

table with one row per movie

heading is just another row in the table

relies totally on juxtaposition

'Book' and 'Search' sections

forms using different layouts

proximity of labels and fields important

lack of consistency in spatial relationships

Form submission

Go and Vote buttons

City and Movie drop down lists

All submit to the same URL

• Makes interpretation a nightmare
  • For assistive technologies
  • For transcoders

Semantic Enrichment

• Adding semantics to markup languages via annotation
• Work in Accessibility and Device Independence at W3C
  • Joint work and cross-fertilization
• W3C DIWG Workshop on Metadata for Content Adaptation
  • What metadata do we need for adaptation to different devices?
  • Focus on small mobile devices
  • Identified key concepts
    • role
    • importance
    • relationship
• W3C WAI-PF Role Taxonomy
  • Key roles needed by assistive technologies

Advances in Semantic Enrichment

• Recent Mozilla Firefox Extensions
  • Support for the WAI Role Taxonomy in existing XHTML
  • <table id="table1" x2:role="wairole.spreadsheet"> ...
  • Support for Accessible Dynamic HTML
• XHTML Version 2
  • Flexible support for linking additional semantic information
    • Including WAI Role Taxonomy
    • Including arbitrary RDF
• DIWG Device Independent Authoring Language (DIAL)
  • Profile for device independent authoring
  • Includes all the facilities of XHTML Version 2
• Such advances in markup help
  • Assistive technologies
  • Adaptation
  • Transcoding

Semantically Rich Markup Languages

• Annotation is a big step forward, but...
  • It relies on authors doing the right thing
  • It is compromised on poorly structured pages
    • There may be nothing semantically meaningful that can be annotated
• Building semantics into markup is a complementary approach
  • Easier for authors
  • Less prone to error
• Add facilities that are inherently semantically rich

Expressing Simple User Interface Semantics

• Express the meaning not the rendering
  • XHTML V1 - Radio Button
  • XForms (in XHTML V2 and DIAL) - Single Selection
• This is significant, though it seems small
  • Allows a variety of rendering for different devices
  • Allows a variety of rendering for different users
• Rendering might be
  • Radio button
  • Drop down list
  • Set of buttons
  • Series of links
  • Spoken text
  • etc.
• Separation of Concerns

Expressing Application Semantics

• Directly express application concepts
• From previous movie site example:
  • title
  • director
  • leading actor
  • genre
  • audience suitability
  • ...
• Very precise but ...
• Unlikely to be shared even within an industry
• Some Mobile Operator Portals have attempted this in the past
  • Lack of standardisation is an issue for content providers
• Detailed representation needs full power of RDF
• Are there simpler, complementary approaches?

Higher Level User Interface Semantics

• What sort of abstractions and representations might be needed?
• Map
  • high resolution image
  • lower resolution zoomed section of image
  • textual instructions for locating a place
  • spoken instructions for locating a place
• Business Card
• Calendar
• ...
• Where is work being done?
  • Microformats - one source of ideas
  • W3C Web Application Formats Working Group - additional UI markup primitives
  • W3C Device Independence Working Group - separation of concerns

Semantics and Adaptation (1)

• Traditional Web architecture is based around the 'page' as fundamental unit
  • What an author creates
  • What a user perceives
• For device independence, DIWG introduced the concept of Adaptation
  • Author creates Authored Units
  • Authored Units are adapted
  • User experiences Perceivable Units
• Adaptation
  • Selection
  • Generation
  • Modification
• Delivery Context provides information
  • about device
  • about network
  • about preferences

Semantics and Adaptation (2)

• Same page as before
  • Rendered for a small mobile device
• Author specified only Logo and Search on mobile
  • Adaptation selected those sections
• Author specified different layout for mobile
  • Adaptation generated the page appropriately

Device Independence and the Mobile Web

• W3C Mobile Web Initiative promoting use of web on mobile devices
• Started in 2005
• First publications are on Best Practices for creating sites
• Providing additional requirements to other groups
• Working closely with groups such as DIWG

Conclusion

• Tensions on the web
  • Social and political
  • Technical control vs. technical freedom
  • Author vs. end user
• Who has control, author or user?
• Author's have not served users with disabilties well enough
  • such users feel compelled to take control
  • hence 'author proposes, user disposes'
• Concepts like Adaptation may offer an alternative
  • Content adapted to suit devices, users ...
• The Dream
  • The user experience is always appropriate
  • Users don't feel compelled to have to take control
  • Wouldn't that be something?