SADIe - Exposing Implicit Information to Improve Accessibility

SADIeExposing Implicit Information to

Improve Accessibility

Darren LunnSchool of Computer Science

The Web…• Designed with a focus on presenting information in a

visual manner● Images● Columned Layout● Chunks

• Some knowledge is only available implicitly from how the page looks

Implicit Knowledge

= Advertisement

= Banner

= Main Content

= Menu

Assistive Technologies

• Traversal of content is in a serial “top-to-bottom”, “left-to-right” manner.

• Important information may not be encountered until later on.

• Also, information such as menus or navigation may be repeated for every page on a site● This can prove tiresome if the user has to wait for the reader

to read the menu each time a new page is visited.

Transcoding

• Rules / Patterns● Can Adapt a large number of pages● Can Suffer from Reduced Accuracy Issues

• Annotation● Accurate● Time Consuming As Every Page Is Annotated

SADIe Approach

• The visual rendering of a Web element informs the user of its purpose

• The CSS defines the visual rendering

• Identifying the purpose of a CSS definition implicitly identifies the purpose of the Web element

• A single CSS definition is applied to every page within the Website

SADIe Functionality

• Defluff: Removes any element that is considered unnecessary

• Reorder: Rearranges the page by putting important information near the top

• Menu: Exposes the menu at the very top for immediate access

Original CNN

SADIefied CNN

Evaluation

• We want to show that using SADIe decreases the time it takes to find information on the page

• Only a small number of users available for evaluation

• Use Randomization Testing● Data analysis techniques suitable for small numbers of users

A-B-A Reversal Method

• Two Conditions; A and B● Condition A: Unmodified Pages● Condition B: Pages Adapted With SADIe

• Present the participant with Condition A tasks

• At a random point, switch to Condition B tasks

• At a second random point, revert back to Condition A tasks

• This reduces the influence of external factors on the results● Participant has time to relax● Participant becomes familiar with the task at hand

Evaluation Method

• 20 pages that had similar content that was predominantly text based● News e.g. CNN, BBC, New York Times…● Blogs e.g. Blogger, Xanga…

• Asked the user to find facts that were as similar for each page possible● Eg for news sites “What is the headline of the news story?”

• The user was presented with a page one at a time, some of which were SADIefied (Condition B)

• We timed how long it took the user to answer the question

Evaluation Results

75

21.143

50.429

0

10

20

30

40

50

60

70

80

A B A

Condition Shown To User

Sverage Time To Complete Task (s)

Evaluation Results

• So far we have evaluated SADIe with a single user

• Results are encouraging and are significant using Randomization Testing…

• … but are currently recruiting more users to support our results.

Further Work

• This is still preliminary work, and much remains to do

• Extend and Enhance the Transformations

• (Semi)-Automation of CSS classification

• More User Evaluations

Conclusions

• Browsing the Web can be difficult for those who are visually impaired

• SADIe can adapt Web pages by using rendering information extracted from the CSS

• Initial evaluation results are promising and show that SADIe can help visually impaired users reach content more quickly

• More work still needs to be done

Questions?

http://hcw.cs.manchester.ac.uk/research/sadie