Google DTorial: An interactive tutorial framework for blind users in a Web 2.0 world - Manual (Page 2)

flash and text+image) rely on visual presentations of context inaccessible to the VIU.
Further, traditional Web-based tutorial systems provide poor access to content with
assistive technology.
This paper addresses the unique challenges for visually impaired users using web-
based tutorial and help systems. We have designed an interaction model specifically
addressing the needs of audio-based tutorials systems for Web applications and screen
readers. Our interaction model is demonstrated through our fully functional tutorial
system, DTorial (Dynamic Tutorial). This model and implementation provide a
mechanism allowing the VIU to learn the interface of a Web application through
embedded tutorial information and an interactive control mechanism. The design is
based on a set of interviews with visually-impaired computer users, best practices in
existing literature, and an analysis of screen reader interaction with Web 2.0
applications. Our system was further informed through a rapid design and evaluation
cycle with 17 VIUs. The foremost contribution of our model is the demonstration of a
functional and accessible tutorial that can be integrated easily into the Web-
application environment.
2 Definitions and Terminology
Visually impaired individuals range from those who are mildly near or far sighted, to
those who are legally blind, to those who have no vision at all. Those with the most
vision loss cannot rely upon sight at all to interact with the world around them.
Approximately 1.5 million visually-impaired individuals live in the USA [3] and the
worldwide statistics put the number at 161 million (about 2.6% of the world
population [33]). For the purpose of this study, we define individuals who cannot rely
upon sight for computer interaction as being Visually Impaired Users or VIUs.
Visually impaired individuals have learned to adapt to and augment many aspects
of the world around them, for instance, with the Braille system [2]. As computer
systems have become ubiquitous, technology also has adapted to meet the needs of
these users [25]. One form of assistive technology, the Screen Reader, converts digital
text to audio speech or Braille output. Common screen readers include Freedom
Scientifics’ JAWS, GW Micro’s WindowEyes, and Apple’s VoiceOver. This
software allows users to navigate computer applications and web pages through a
series of keyboard commands, while having the content read back to them. This
content can be presented as either speech or on a refreshable Braille display [4]. For
this experiment, we used audio feedback. We use the term "read" or "reading" to
indicate the user is listening to a screen reader converting text to spoken audio. In this
experiment we used the JAWS Screen Reader, the most popular screen reader [13].
3 Existing Technology & Limitations
Research in screen readers is ongoing in HCI. Jim Thatcher captured the philosophy
best in 1994: “blind users must have access to the same computing environment as
their sighted colleagues” [30]. Since then, much work has helped make computers