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User-Centered System Design

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User-Centered System Design
Universal Access to Technology
User-centered system Design is iterative!
DESIGN
TEST
Case Study:
Computer Aided Conversation
for Severely Physically Impaired
Non-speaking People
(Norman Alm et al.)
Why I like this article
Solves a real problem
 Tells a clear story
 Did a terrific analysis of the task
 Technical solution is informed by a
theory of communication
 Good evaluation at the end

Conversation
Turn-taking
 Adjacency pairs
 Topic structure
 Perspectives

What the researchers did:

Task analysis
 Had
real user in mind
 Simulation with index cards
 Role playing
 Iteration
Screen design
 Evaluation

 Healthy
users
 Non-speaking user
Computer-assisted conversation
A: I went to France last year, to Marseilles.
B: I’ve never visited Marseilles, I’ve sort of driven round the
outskirts, but never actually gone into Marseilles.
A: Surprisingly, it’s really beautiful.
B: Really? I just imagine it as sort of a port, and just like any other
large city, with nothing particularly interesting.
A: You expect a major port to be fairly grotty, don’t you ?
B: [LAUGHl That’s right [LAUGH].
A: We also visited other places on the coast, but we decided to
give St. Tropez a miss.
B: That’s one place I’d like to go.
A: I’ve heard it’s pretty grotty now, and crowded.
B: Really ? Oh, well, maybe give it a miss then. Of course, there’s
always the chance to see Brigitte Bardot there.
A: Whatever turns you on.
What’s the web like if you can’t see it?
A point of view by Chieko Asakawa


Section 508 of the Rehabilitation Act: All
federal agencies must make their info
available to people with disabilities
How?

Screen readers, alt texts, skip-navigation links
More and more images, with more
and more “alt texts”
What’s the web like if you can’t see it?
“These days, Web pages are becoming larger and
visually more complex using layout tables, images,
colors and other visual effects. Thus, one page
contains more various types of information than ever
before. This means that blind users need to spend
more time on one page to extract the information
they need, since voice browsers (in this discussion,
voice browser means both self-talking browsers and
screen readers) present information serially using a
text-to-speech (TTS) engine.”

(from Asakawa, 2005)
Skip navigation link
Alt text
The irony: sometimes the very features
meant to make the page more
accessible actually makeit worse
 Asakawa’s example of empty images
used to space real images: With no alt
text, these were invisible to her. With
alt text added, she had to listen to lots
of “spacer gif” readouts!

Some ways of improving accessibility:

Guidelines, legislation, and standards


(skip links, content anchors, alt text, etc.)
Have sighted designers experience a web page as
the blind do!


aDesigner - simulates blind experience
Estimates “reaching times” for key parts of page
aDesigner
Inaccessible parts
are darkened
Some ways of improving accessibility:

Guidelines, legislation, and standards


Have sighted designers experience a web page as
the blind do!




(skip links, content anchors, alt text, etc.)
aDesigner - simulates blind experience
Estimates “reaching times” for key parts of page
“Intelligent” parsing of web pages (HearSay)
Treat form-filling as a kind of dialogue


See Tony’s fax form example
Include methods for repair and managing interruptions
Fly UP