Download Internet Surfing for Blinds: A prototype

Internet Surfing for the Blind: A prototype
(published in Journal of Electronic Library, volume 21, number 6, p.575-586, 2003)
Alfred Loo and Ming-te Lu
Lingnan University
Chris Bloor
University of Sunderland
ABSTRACT
The right of blind people to access the Internet is simply ignored in many
countries because Web pages have been designed for normal people. As a result,
many blind people are not enjoying the benefits of the Internet and the improvement
in the quality of life that Internet use can bring. In order for visually impaired persons
to surf the Internet, it is necessary to develop a special human-computer interface
system. This paper presents the design of a Web project for the blind. The aim of this
research is to develop a new human-computer interface model and an associated
computer system for visually impaired people so that they can browse the World
Wide Web via Internet. An assessment of the potential of a wide range of applications
and their impact are also presented.
Keywords: Human Computer Interface, Internet Surfing, Blind
INTRODUCTION
It is estimated that there are 54 million people in the United States with a
disability. The Congress of United States enacted the Americans with Disabilities Act
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(ADA) in 1990 and passed amendments in subsequent years that “prohibit
discrimination on the basis of disability in employment, programs and services
provided by state and local governments, goods and services provided by private
companies, and in commercial facilities.”(http://www.usdoj.gov/crt/ada/publicat.htm).
Web sites and pages are also covered under the ADA. The US Access Board also
issues standards (Access Board, 2000) for electronic and information technology
covered by section 508 of the Rehabilitation Act Amendments of 1998. However,
many visually impaired people today still have access problems with most Web sites
(Cynthia et al, 1999). The reason for this phenomenon is simple - many Web page
designers do not test the accessibility of their designs with disabled persons in mind.
The accessibility problem has grown significantly (Marquand, 2000) because more
business and government agencies are relying on the Internet to disperse information
and services.
As it is difficult to define accessibility, the World Wide Web Consortium
(W3C) has outlined an accessibility guideline document in its website (W3C, 1999) to
help web designers. Although this document is quite bulky (34 pages), the idea is
quite straight forward. If information is conveyed through color, sound, or image, an
alternative description should be placed in the html file. The alternative description
can then be read by a “Screen Reader” for people with disabilities . Row and column
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headings should be used to give direction to users if tables are used in the web pages.
This document recommends 14 guidelines and 105 checkpoints. These
checkpoints are classified into three priority levels. Conformance Level “A” will be
awarded to web pages which satisfy all priority 1 checkpoints. Conformance Level
“Double-A” will be given to web pages which satisfy all priority 1 and 2 checkpoints.
Conformance Level “Triple-A” is the highest level. A web page must satisfy all
priority checkpoints in order to be awarded “Triple-A” conformance.
It is quite time consuming to validate all 105 checkpoints for each web page.
Automatic validation tools do exist and are generally fast and convenient, but they
cannot validate all accessibility issues. Human review is still required to ensure a web
pages’ conformance. The World Wide Web Consortium thus recommends both
automatic validation and human review.. Among the available automatic validation
tools, Bobby (http://www.cast.org/bobby) is one of most well known software
packages.
Bobby was developed by a non-profit organization called the Center for
Applied Special Technology (CAST). Users can submit a web page to Bobby by
typing the URL of the page at CAST’s web site. Bobby can then examine the page
and report accessibility problems. This method will only check one page at a time in
order to keep the server available to all. A downloadable version of Bobby, which can
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check web pages in a whole web site in batch mode, is also available. A web designer
earns the right to display a Bobby icon on his/her web page if it passes the Bobby test.
Even with the protection of ADA and availability of automatic tools, recent
accessibility studies (Jackon-Sanborn et al, 2001) using Bobby show that the majority
of U.S.-basedweb sites do not meet the Web Content Accessibility Guideline in
http://www.w3.org/WAI/GL (Waddell 1999). In many developing countries, the lack
of access to the Internet for disabled persons is even worse. People with disabilities in
these countries are not protected by laws similar to ADA in the U.S. The access
problem is simply ignored by web designers as they do not believe that they should
make the Web sites accessible to people with disabilities. It is even more urgent to
find a solution in these countries.
Many governments realize the importance of Internet and the benefits it can
bring to their populations. These governments have invested heavily to promote the
use of the Internet. However, blind persons cannot receive benefits from these
investments as they cannot see the information presented via Internet on a computer
screen. It is practically impossible for them to use the Internet as they cannot position
the cursor to a particular location on the screen using the mouse.
This paper presents a new human computer interface designed1 to solve Internet
1
This project is supported by the Quality Education Fund of Hong Kong SAR Government.
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accessibility problems encountered by blind people. English “screen reader” programs
for blind people are already on the market, but an efficient Chinese-language screen
reader for Web browsing is not available yet. Hong Kong-based Web sites routinely
contain both Chinese and English characters on the same Web page, making a screen
reader for this market more difficult to develop. This new human computer interface
can deal with mixed language content and can be used by very young and very old
segments of the population as well as by visually impaired people.
BACKGROUND INFORMATION
The Internet is the most well-known component (Kalakota and Whinston, 1996)
of the Information Superhighway network infrastructure which spans several
continents and is the backbone of electronic commerce. Indeed, Internet use is
expanding faster than any other communication technology in history and has the
potential to significantly impact the major portion of the population in any society.
The Internet’s ability to transmit multimedia content overcoming time and space
constraints has created exciting and unforeseen opportunities in commerce,
communication, education, science, politics, international relations, and many other
fields. The Internet has played a major role in stimulating the global economy and has
a profound impact on the quality of life for its users. However, a digital divide exists.
People with disabilities are often left out of this Internet revolution.
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In the early stages of Internet, only text information was available on the Internet.
The text LineMode Browser (Walsh 1996) in 1991 was quite different from the Web
navigation tools we know today. It did not support the mouse or graphics and was
difficult to use. The first multimedia browser (MOSAIC) to boast a user-friendly
graphical user interface (GUI) was released in 1993. MOSAIC was considered to be
a breakthrough software product as it advanced the World Wide Web into a
multimedia system. Today, the Internet can deliver text, video, sound, human speech
and graphics. The mouse and hypermedia are employed to make it easy to navigate
the Internet and search for information. The latest Web browsers, Netscape Navigator
and Microsoft Internet Explorer, have further improved on the functions of MOSAIC
and use similar technologies. Although the mouse and hypermedia are great interface
tools for "normal" people, ironically they create barrier for visually impaired persons
to access the Internet. Today, there are many new applications for the Internet such as
Internet banking, Internet shopping, Internet voting, Internet telephone and Internet
television. Internet is also being used for education and for seeking employment.
However, visually impaired persons are not able to obtain the full benefits of Internet
because it is nearly impossible for them to navigate the Internet with the existing
browsers.
Thus, new human-computer interfaces need to be developed to enable
them to enjoy the benefits of the Internet.
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Human-Computer Interface
Research in human-computer interfaces (HCI), an important area of software
design, has been very active and references abound. However, most research has
been based on the assumption that the user possesses normal eyesight. Research work
on access tools for blind people is lacking. For example, visual design is often
stressed in the design of human-computer interfaces with the objective of providing
visual attributes that contribute valuable impressions and communicate important cues
to a user. Various approaches have been suggested, and technologies developed, via
which visually impaired persons can access the Internet and surf the Web. These
approaches and their limitations are presented in the following sections.
Text Browsers
To avoid problems of using the mouse and hypermedia, most visually impaired
persons use text-based Web browsers (e.g. Lynx) that will ignore graphics on Web
pages and allows the use of the keyboard to activate hyperlinks. However, since
many Web designers only test their designs on popular browsers such as Netscape and
Microsoft Explorer, they often use features that are not supported by text browsers;
blind users often have problems accessing such web sites. Text browsers cannot
completely solve the problems of Internet surfing for the blind.
Screen Readers
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Speech synthesis technology (Allen et al, 1981; Suen, 1981) has been available
since the late 1970s. “Screen readers” (Blenkhorn and Caulderwood, 1992) were
developed in 1980s and blind people can now access most text-based computer
displays using speech generated by screen readers (Meyers and Schreier, 1991).
However, simply reading the text and converting it to human speech will not solve
Internet navigation problems for blind people. First of all, screen reading is usually
done in a batch mode. A real time mode is required for Internet navigation. In
addition, "reading aloud" every item on a Web page and asking the user to make
subsequent choices constitutes a heavy burden on a humans’ short term memory
(Zetie, 1995) making it a poor HCI technique. Also, most “text reading” programs
work independently and cannot interact with popular Web browsers such as I.E. and
Netscape. In order to activate the next Web page, the user still needs to point to a
specific hypertext link and click the mouse, an action which is nearly impossible for a
visually impaired person. Innovative methods must be developed if visually impaired
people are to have uninhibited access to the Internet.
Braille Printout and Braille Devices
Thirty years ago, the output of computer systems was primarily conveyed to
humans via paper printout. As blind computer users cannot read ordinary paper, they
had to read computer output by touching paper specially indented with a pattern of
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raised dots called “Braille” (Lightowler, 1994; Blenkhorn and Evans, 1988). This
technology was named after its inventor - Mr. Louis Braille. He was a blind Frenchman
and his blindness was caused by an accident in his childhood. Braille is not the only
reading and writing system for the blind, but it was considered to be the best according
to several independent studies (Keeler, 1986). Through out the years, his system has
been adopted by many countries all over world. Over 600,000 books, newspapers and
magazines are printed in Braille every year. However, it is much more expensive than
ordinary computer printout and a special printer is required.
A Braille device (Kay, 1984; Leventhal et al, 1991; CSUN’95, 1995) is another
alternate output device for the blind. A small part of the image of a computer screen
can be generated on the device; a visually impaired person can read it quickly by
touching the device and does not have to wait for the generation of the Braille paper.
However, Braille devices are very expensive. A typical device costs about US$6,000
while the cost of a Pentium-based computer is only US$1,000. People with
disabilities generally have far lower incomes than other citizens (National Council on
Disabilities, 2001). Most visually impaired computer users cannot afford to buy a
Braille device. A cheaper and more reliable output method for the blind is necessary.
The speech option meets these criteria and thus it is chosen as the major navigation
method for this project.
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ADVANTAGES OF THE KNOWLEDGE BASED APPROACH
The knowledge based screen reader system provides many advantages for the
system as it can be extended by adding to/ replacing its knowledge base for a variety of
applications. For example, the interface system can be modified so that visually
impaired persons will be able to use other popular programs such as Microsoft Word,
Excel, etc. by changing the knowledge base of the resident program.
VOCALSURF: A INTERNET SURFING TOOL FOR BLINDS
A HCI system especially designed for Internet surfing by visually impaired
people was developed as part of a project funded by the Quality Education Fund (QEF)
of Hong Kong. The key objective of the project was to produce a prototype to assist
blind people to understand the contents of Web pages through speech and, using simple
keyboard instructions, to interact with the various components of a Web page. The
design of the prototype and its components are presented below.
Design of the Prototype
As the Overview of the System (Figure 1) shows, the basis of the system is that
resident programs read HTML pages downloaded via Web browser, and with the help
of dictionary files and knowledge bases. produce human speech. The human speech is
used by visually impaired persons to guide their interaction with the browser. They in
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turn can provide their input through the use of special input device or a regular
keyboard that generates emulated mouse.
End user's computer
Resident Programs
Input Device
HTML
Pages in
Memory
Emulated
Mouse
Signals
Dictionary
and Wave
Files
Knowledge
Base of
HTML
Sound and
Human
speech
Internet Browser
Internet
Figure 1. Overview of the new system
Specifically, the resident programs have the following functions:

Interaction with the Internet browser

Selectively reading part of the text in Web pages and producing human speech;

Receiving signals from special input unit and emulating a corresponding
mouse signal to the browser.
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Components of the system
HTML Source in
Memory
Signals From
Input Device
Input
Handler
Mouse
Emulator
Emulated
Mouse Signal
User
Interface
Knowledge
Base of
Internet
Browser
Inference
Engine
Knowledge
Base of
HTML
Voice
Synthesiz
er
Dictionary
and Wave
Files
Human
Speech
and Vocie
Figure 2. Components of the resident programs
As described in Figure2, the resident programs of the HCI system consist of the
following modules:

Input Handler
This module accepts input signals from the Input Device and passes the signals to the
user interface unit.

User Interface
This module takes input messages from the Input Handler module and interprets the
signals with the help of an Inference Engine. It then sends the signal to the Mouse
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Emulator.

Inference Engine
The Inference Engine gets rules from the Internet Browser and HTML knowledge
bases . It matches an input signal against the corresponding “mouse click” if action
from the browser is necessary. It also selects sentences/words and pass them to the
“voice synthesizer” module.

Voice Synthesizer
The voice synthesizer generates human speech by matching selected words/sentences
on the Web page with those in dictionaries and wave tables.

Mouse Emulator
The Mouse Emulator module emulates a corresponding mouse signal and passes it to
the Web server.
Development of the prototype
The prototype of this project was called VocalSurf. It was designed to operate
on any Internet-ready personal computer using Microsoft Windows 95/98 as a single
application program after installation. The hard disk capacity required is 128
megabytes (MB). Users interacted with VocalSurf using speech and keyboard. Users
typed in simple instructions and VocalSurf read back specified Web page content to
the users. In other words, VocalSurf was designed as a WWW surfing tool for blind
or visually impaired individuals.
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Technologies Applied
To make VocalSurf functional, the following technologies were employed, in
addition to object oriented programming techniques:
 Microsoft Sound Application Programming Interface (SAPI);
 Sound Wave Manipulation;
 Component Object Modelling (COM).
Microsoft SAPI technology was the core technology applied in VocalSurf’s
English speech engine construction. In constructing the Cantonese speech component
of VocalSurf, since SAPI for Cantonese is not available from Microsoft, sound wave
manipulation using audio compression techniques and COM technologies were
adopted to simulate a SAPI for a Cantonese speech engine. Rapid Application
Development was adopted in software development to facilitate continuous
prototyping.
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Mechanisms Implemented
The following diagram illustrated the overall architecture of the sound engine:
Text Strings
API Wrapper
VocalSurf Sound Engine
WAV
Database
SAPI
Figure 3: Sound Engine
End-users interact with VocalSurf by means of User Interface using the keyboard
and control keys are summarized in Table 1. Messages are then carried forward to the
VocalSurf Sound Engine, which parses the requested Web page for meaningful
content.
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Key
Combinatio
n
CTRL
SHIFT B
SHIFT S
SHIFT L
Function
Focus on URL input
Begin reading
Stop reading
List the current 10
hyperlinks
SHIFT =
Move on to the next 10
hyperlinks
SHIFT Return to the previous
10 hyperlinks
SHIFT 0...9 Select a particular
hyperlink in the current
10 hyperlink listing. (If
the current 10 hyperlink
listing is from 11 to 20,
0 will be 20, 1 will be
11, 2 will be 12, etc.
Backspace Go back
ALT 
Go to a page ahead of
the current page
Table 1: Control keys for the System
The engine also determines if the reading content is Chinese or English. English
content is directed to an API Wrapper for SAPI to process. If the content is Chinese,
every word will be matched against a database for the corresponding wave
compressed files. When processing by either Database-WAV or SAPI is complete, the
VocalSurf Sound Engine produces the audio output.
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uses
File
System
Text
Stream
1
1
opens
1
1
activates
1
opens
1
1
1
WebBrowser
calls
1
Menu
1
activates
use
s
1
1
1
1
12
1
1
Common
Dialog Box
1
1
1
updates
1
1
use
s
Form
s
call
ch
ec
k
s
1
1
1
1
activ
1
1
1
ates
1
1
terminates
Text Box
1
1
1
1
3
1
1
a
activ
Command
Button
PlaySound
tes
1
Text-to-Speech
Figure 4: Classes in the Sound Engine
Classes and objects in the sound engine are described in Figure 4. The most
important class in Figure 4 is the “PlaySound” which produces human voice. Its
components are described in Figure 5.
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1
API Declarations: Load dll API, Multimedia API, Error report API, TTS_API_DLL Wrapper API
ApiModule
InitDb
DB & recordset init
Initialize DB & RS objects
Wordlist.mdb
DB
Class_Initialize()
set playFlay to true,
Initialize VB TTS component
(dummy)
Class_Terminate()
Close Erase all DB & RS object
ery
qu
Sound
Output
Recordset & DB
Objects
dbs, rst1, rst3, rst4
Microsoft
SAPI
getWaveName
Args: Char, prefix-char, suffix-char
Return: wave index (in clsPlaySound.dll)
EngToChi
Args: Integer
Return: String of number in Chinese
call
playFlag
DigitConvert
Args: Integer
Return: String of digit (0
- 9) in Chinese
Boolean
Reset
Speak
SetPlayFlag
isSpeaking
TTS_API_DLL.dll
StopPlaying
call: Reset,
sndPlaySoundFromMemory
vbNullString
call
PlayString
Args: String
Process: Load clsPlaySound.dll, check playFlag, call
getWaveName, locate & play mem wave file
Sound output
and
Find
f il e
wave
Load
Check if true
y
emor
to m
playStringEng
Args: English String
Process: call TTS Wrapper functions( Reset, Speak
& isSpeaking)
call
PlayStringAll
Args: Source String
Process: loop based on the length of source string,
examine the ASCII code of each character, call PlayString
& playStringEng recursively. Set playFlag to false exit
set playFlag the loop
set playFlag to False
clsPlaySound.dll
PlaySound.cls
call
String to paly
VocalSurf.vbp
call Reset
set playFlag to False
Figure 5: Components of “PlaySound” Class
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Testing
The strategies adopted in testing VocalSurf included internal testing and user
testing. Internal testing of VocalSurf consisted of three phases:,. unit testing, module
testing and system testing. Internal testing was carried out by our research staff while
the user testing was conducted by our research partner – users from the Hong Kong
Blind Union.
During unit testing, each event or function of VocalSurf was tested. In module
testing, VocalSurf was grouped into three modules: User Interface, Engine and API
Wrapper. Each module was tested repeatedly for errors.
Finally, during system testing, VocalSurf was functioned as a complete, selfsufficient Web browsing tool and was stress-tested by repeatedly processing files with
large amounts of text. .
Blind users of VocalSurf were involved in the user testing of each prototype. In
addition to assessing the accuracy and reliability of the system, users’ comments on
usability (such as the speed of the human speech output) were also collected.
Comments and suggestions from blind users were used as input for the next prototype
cycle. We went through four cycles of prototype development in this project.
Constraints and Future Improvement
We have successfully developed a prototype which can produce human voice by
reading web pages. It can also read a text file which consists of a mixture of English
and Chinese characters. Due to funding constraints, there are still some limitations in
this prototype. However, these limitations can be addressed easily if we receive more
resources in the future. The limitations at this moment are:
 the readable text volume
 the variation of sound
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 the control in reading
The following paragraphs provide further elaboration of those constraints.

Readable Text Volume
The maximum amount of text VocalSurf is able to process after HTML tag and
non-text object parsing is 4500 bytes. Any Web page with a text amount over that
limit will incur variable-overflow error.

Sound Variation
A single Chinese character may have two or more different pronunciations (and
meanings) which are distinguished, by sighted readers, from context and usage in the
sentence. VocalSurf is not yet capable of detecting the required alternations in
pronunciationAs for the intonation and the option of varying the output sounds
according to the "speaker’s" gender and age, VocalSurf does not support any changes
in this aspect either.

Reading Control
If the user needs to stop while VocalSurf is reading, (s)he is allowed to do so.
However, VocalSurf cannot restart reading at the point it stopped previously, or repeat
what it has just read.
POTENTIAL APPLICATIONS
Although this prototype has been developed for blind people, it can also be used
by people with normal eye-sight. The system will also accept normal mouse signals as
an ordinary Internet browser. The operations are similar to Internet Explorer as in
Figure 6. Potential applications for these kind of users are discussed in the following
sections.
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Figure 6: The outlook of VocalSurf for users with normal eyesight
For Young Children
Children under 9 years of age generally have problems accessing the Internet as
they do not yet possess a large vocabulary. Although they may have normal vision and
a large spoken vocabulary, they cannot read many words on the Web pages. However,
with the help of our VocalSurf prototype, young children can surf the Internet as they
can understand the contents of Web pages via human speech. The system may find
applications in kindergartens and primary schools.
Translation of Web pages
Many high school students in non-English speaking countries are not able to to
maximise use of the WWW due to their limited knowledge of English (the vast
majority of WWW pages are in English). By incorporating a “translation” module with
Chinese and English knowledge databases (Figure 7), the proposed system can translate
content from English to Chinese (or any other language) first and then convert to
spoken Chinese (or any other language) words. Thus the system could also be used by
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secondary school students, regardless of their eyesight. The proposed system could
open up a new world on the World Wide Web for any non-English speaking population.
English HTML
Source
User
Interf ace
Know ledge
Base of
Internet
Brosw er
Inf erence
Engine
Know ledge
Base of
HTML
Selected English
Sentences /
Words
Syntactic Parsing
and Semantic
A nalysis
Know ledge
of Base
Chinese
Language
Language
Generation
V oice
Synthesizer
Know ledge
Base of
English
Language
Translation
Module
Semantic
Grammer
Chinese
Dictionary
and Wave
Files
Chinese
Speech
Figure 7. Component of Translation Module
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For Older Persons
A large percentage of older people in many developing countries are illiterate
and thus cannot use the Internet. Even for literate older people, screen reading for long
periods of time is very tiring. Older people could also benefit from the proposed system.
Hands Free Browsing
If the Input Handler module is replaced with a Voice Recognition module in the
system, people with disabilities in their hands would be able to use the system for Web
browsing (Figure 8). This change would also benefit normal people who want to
access the Web when their hands are tied up doing something else.
HTML Source in
Memory
Human
Speech
Computer
Microphone
V oice
Recognition
Mouse
Emulator
User
Interface
Inference
Engine
Knowledge
Base of
HTML
Voice
V oice
Synthesi
Synthesizer
zer
English
Dictionary
and Wave
Files
Earphone/
Speaker
Emulated
Mouse Signal
Knowledge
Base of
Internet
Browser
Chinese
Dictionary
and Wave
Files
Human
Speech
and Vocie
Figure 8. System with Voice Recognition
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Many people listen to music or radio broadcasts using a personal stereo while,
for example, waiting for buses/trains. With the latest technologies, network computers
can be built as small as a walkman. Incorporating the knowledge-based HCI system
described above into such a small network computer would enable Web browsing
while travelling or commuting.
CONCLUSION
Visually impaired persons and the blind can derive great benefit from VocalSurf.
It will make them independent users of the WWW, and consequently enhance their
independence as members of wider society. Maximising the use of their computers as
portals to the Internet and its myriad services will improve their opportunities in
education and their access to information, vastly improving their quality of life.
A HCI system such as VocalSurf would also broaden the profile of the Webusing population, enabling as more children and elderly people will become Internet
users in the future. A knowledge-based HCI system such as VocalSurf could have a
substantial impact on reducing the "Digital Divide", and in addition could broaden and
deepen markets for internet services.
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