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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 CASTs 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 designed1to solve Internet

accessibility problems encountered by blind people. English screen reader programs

1 This project is supported by the Quality Education Fund of Hong Kong SAR Government.

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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 Internets 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; CSUN95, 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

turn can provide their input through the use of special input device or a regular

keyboard that generates emulated mouse.

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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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Resident Programs

Internet Browser

End user's computer

Internet

Sound and

Human

speech

HTML

Pages in

Memory

Emulated

Mouse

Signals

Dictionary

and Wave

Files

Knowledge

Base of

HTML

Input Device


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Components of the system

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.

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Signals From

Input Device

Input

HandlerUser

Interface

Inference

Engine

VoiceSynthesiz

er

HTML Source in

Memory

Knowledge

Base of

HTML

Human

Speech

and Vocie

Mouse

Emulator

Emulated

Mouse Signal

Knowledge

Base of

Internet

Browser

Dictionaryand Wave

Files


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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

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 prototypeThe 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

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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.

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 VocalSurfs

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:

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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Text Strings

VocalSurf Sound Engine

Database

API Wrapper

SAPI

WAV


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Key

Combinati

on

Function

CTRL Focus on URL input

SHIFT B Begin reading

SHIFT S Stop reading

SHIFT L 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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Menu

CommandButton

PlaySoundText Box

CommonDialog Box

Text-to-Speech

WebBrowser

Form

activates

uses

activates

updates

activa

tes

12

11

1

11

1

1

1

1

1

1

1

3

activates1

1

1

1

checks

1

1

1

1

1

1

1

1

uses

1

1

calls

1

1

terminates

1

1

1

1

calls1

1

FileSystem

TextStream

opens

opens1 1

1 1

uses

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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Figure 5: Components of PlaySound Class

VocalSurf.vbp

PlaySound.cls

SetPlayFlag

playFlag

InitDbDB & recordset init

Boolean

Recordset& DBObjects

dbs, rst1, rst3, rst4

StopPlayingcall: Reset,

sndPlaySoundFromMemoryvbNullString

getWaveNameArgs: Char, prefix-char, suffix-char

Return: waveindex (in clsPlaySound.dll)

PlayStringArgs: String

Process: Load clsPlaySound.dll, check playFlag, callgetWaveName, locate& play memwavefile

playStringEngArgs: EnglishString

Process: call TTS Wrapper functions( Reset, Speak& isSpeaking)

PlayStringAllArgs: SourceString

Process: loop based onthelength of sourcestring,examinetheASCI I codeof eachcharacter, call PlayString

& playStringEngrecursively. Set playFlagtofalseexittheloop

EngToChi

Args: IntegerReturn: Stringof number in Chinese

DigitConvertArgs: Integer

Return: Stringof digit (0- 9) in Chinese

call

call

call

Initialize DB & RS objects

set playFlag

Wordlist.mdb

DBquery

clsPlaySound.dll

FindandL

oadwavef

iletomem

ory

set playFlag to False

Soundoutput

set playFlag to False

call

TTS_API_DLL.dll

Reset

Speak

isSpeaking

String topaly

call Reset

MicrosoftSAPI

SoundOutput

Check if true

Class_Initialize()set playFlay to true,

Initialize VB TTS component(dummy)

Class_Terminate()CloseEraseall DB & RS object

ApiModule

API Declarations: Loaddll API, MultimediaAPI , Error report API , TTS_API_DLL Wrapper API


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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, self-

sufficient 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

the control in reading


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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 "speakers" 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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English HTML

Source

User

Interface

Inference

Engine

Knowledge

Base of

Internet

Broswer

Knowledge

Base of

HTML

Selected English

Sentences /

Words

Syntactic Parsing

and Semantic

Analysis

Semantic

Grammer

Language

GenerationKnowledge

of Base

Chinese

Language

Translation

Module

Knowledge

Base of

English

Language

Voice

Synthesizer

Chinese

Dictionaryand Wave

Files

Chinese

Speech

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 readmany 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

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.


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Figure 7. Component of Translation Module

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.


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Voice

Recognition

User

Interface

Inference

Engine

Voice

Synthesizer

HTML Source inMemory

Knowledge

Base of

HTML

Chinese

Dictionary

and Wave

Files

Mouse

Emulator

Knowledge

Base of

InternetBrowser

EnglishDictionary

and Wave

Files

Computer

Microphone

Human

Speechand Vocie

Earphone/

Speaker

HumanSpeech

Voice

Synthesizer

Emulated

Mouse Signal

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.

Figure 8. System with Voice Recognition

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


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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 Web-

using 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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Standards, Federal Register on December 21, 2000.

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Allen, S., Songco, D., Plexico, P., & Morford, R. (1981). A Voice Output Module

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Blenkhorn, P., & Caulderwood, D. (1992).Access to Personal Computers using Speeck

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Blenkhorn, P. and Evans, D. (1988), Using Speech and Touch to Enable Blind People

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CSUN95 (1995), A cornucopia of Access Technology, Technology Update Sensory

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Kalakota, R. and Whinston, A.(1996), Frontiers of Electronic Commerce, Addision

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Waddell, D. and Thomason, L. (1999), Is Yours Site ADA-Compliant or a Lawsuit-in-

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