Speech as Interface in Web Applications for Visually Challenged E-Book

Prabhat Verma

• Herausgeber: GRIN Verlag
• Sprache: Englisch

Veröffentlichungsjahr: 2015

Beschreibung

Doctoral Thesis / Dissertation from the year 2013 in the subject Computer Science - Miscellaneous, , course: Computer Science and Engineering - Human Computer Interaction, language: English, abstract: This book addresses to some of the important issues, challenges and approaches related to web accessibility in context of visually impaired users. Speech is a convenient medium of interaction for visually challenged users, Internet accessibility for them is made possible by providing an alternative speech-based interface for human-computer interaction. Problems associated with speech based web interfaces are manifold. Most of the web content available today has been designed for the visual interface via graphical browsers. Screen Readers have been the primary tool for using internet by visually impaired. Unfortunately, most of the popular and workable screen readers are proprietary and bear a heavy price tag. Thus, Design and development of powerful yet affordable speech based interfaces would be certainly helpful in enhancing the overall Quality of Life of visually challenged.

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CERTIFICATE

Certified that Mr. Prabhat Verma (Enrollment No.09001001013) has carried out the research work presented in this thesis entitled "Speech as Interface in Web Applications for Visually Challenged" for the award of Doctor of Philosophy from Uttarakhand Technical University, Dehradun under my supervision. The thesis embodies results of original work, and studies are carried out by the student himself and the contents of the thesis do not form the basis for the award of any other degree to the candidate or to anybody else from this or any other University/Institution.

 (Dr. Raghuraj Singh)

 Professor

Harcourt Butler Technological Institute,

Kanpur (Uttar Pradesh). India.

Abstract

This research work addresses to some of the important issues related to web accessibility in context of visually challenged users. Accessibility refers to the ability of a user, despite disabilities or impairments, to use a resource. For Internet-based applications, accessibility means that all users can perceive, understand, navigate, interact with, and contribute to the Web. Speech is a convenient medium of interaction for visually challenged users, Internet accessibility for them is made possible by providing an alternative speech-based interface for human-computer interaction.

Problems associated with speech based web interfaces are manifold. Most of the web content available today has been designed for the visual interface via graphical browsers. Sighted individuals can quickly locate the information that is most relevant to them. Visual layout of the webpage also helps a lot in efficient browsing of the webpage. But, this task can be time consuming and extremely difficult for people with visual disabilities. Speech based browsers are generally sequential in processing. Thus, a visually challenged user may require ‘listening’ the whole page content in order to reach his/her topic of interest. Also, they are not able to get any layout information of the web page.

Assistive Technologies (ATs) like screen readers make the use of underlying DOM (Document Object Model) structure of the web page to narrate its contents to a visually challenged user. To ensure that ATs work correctly on a webpage, web developers must follow the W3C and other guidelines while creating the websites. Unfortunately, due to lack of awareness among web developers, this requirement is not adequately met and as a result, a large amount of web content remains inaccessible to ATs and visually challenged users. Web 2.0 has further increased this trend by empowering the end user with web authoring capabilities. The role of ATs is thus to expose such inaccessible webpage contents using some clever techniques and present them before the visually challenged user.

Despite their shortcomings, Screen Readers have been the primary tool for using internet by visually challenged. Unfortunately, most of the popular and workable screen readers are proprietary and bear a heavy price tag. For example, cost of JAWS, a popular screen reader by Freedom Scientific for single user license is around $900. This cost is 10 times higher than that of Windows7 operating system! The cost is evidently too high to be afforded by an average Indian individual with visual disability. High cost is also attributed by small product market for assistive tools. There are ATs in freeware domain but they are not popular since most of them may not provide adequate functionalities.

ATs for web access pose greater problems as compare to ATs for Desktop Applications. Microsoft Narrator integrated in Windows 7 Operating System works only for Desktop Applications and not for web access. Findings of a study conducted by Enabling Dimensions, January 2002, New Delhi, reveal that accessing web content was “frustratingly difficult” for visually challenged, implying the need for availability of more accessible and usable web content as well as better software to use the Web effectively by them. Thus, design and develop of usable as well as affordable assistive tools for visually challenged users is an important research issue.

In confirmation to the “Research by Application Development” philosophy adopted and as a part of this research work, an enhanced speech based web browser named ‘WACTA’ has been designed and developed with a vision of providing an improved yet affordable and easy to use web browser for visually challenged users. The system has been implemented in programming language C# and .NET 4.0 framework. Microsoft Speech API (SAPI 5.0) has been used for narration of the text and user input feedback.

WACTA web Browser has several unique features that distinct it from other screen readers. First, the speech based web browser has been implemented completely using .NET managed code. So far, screen readers have been implemented using unmanaged code (Ihtml interface). Implementation in managed code offers better reliability, automatic garbage collection, bounds checking at run-time, improved security etc. Due to limited available functionalities, coding in C# managed code poses greater challenges in ensuring the requisite behavior of ATs. Second, speech features have been integrated in the WACTA browser itself which is implemented using WebBrowser class. Thus, the web browser can be customized for visually challenged users and new functionalities can be added later. It can be used in many modes depending upon the user need and user disability level. Thus, there are link navigation mode, navigate-all mode, interactive mode, newsreader mode, query mode, analytical mode and mouse Glimpse mode (for partially blind user) which can be chosen from among menu or using the key shortcuts. At any time, visually challenged user can make switch over from one mode to another. It aids to minimizing the time required to complete a given task. WACTA complies with the W3C’s User Agent Accessibility Guidelines (UAAG). The prototype is already tested for 25 skilled blind users and they have found it user friendly as it fulfills their basic requirements to access the internet effectively for both routine and important tasks.

 There are important tasks like getting a berth booked on Railways Reservation Website, paying taxes at Income tax website etc. which are complex in nature and have span about multiple web pages. Such task may not be conveniently performed by a visually challenged user with the aid of assistive technologies like screen readers. Besides, the assistive tools may not be installed on a public terminal. This makes a disadvantage for visually challenged users since the web based facility to utilize these public utilities is even more needed for them than their visually able counterparts. Such important public utilities should be universally accessible without the need to install any assistive tool on the computer used. At present, fetching mp3 on a remote web service is the only standard way for converting text to speech. APIs used for this purpose are proprietary and provide text to speech services. In this context, we have proposed two frameworks using which, owners of the public utility websites may directly speech enables their existing websites for more important functionalities at a minimum cost and effort required. The first framework, Speech-Enabler makes use of existing technologies like JavaScript and speech API, therefore provides robust and lightweight solution to the accessibility problem. The other framework, SICE Framework is based on VoiceXML and Voice-Over Internet Protocol (VOIP). It can be used for developing web based interactive voice applications without the need of telephony. Thus, complex web data can be conveniently handled using customized two way dialogue based access system in a controlled way.

To the best of our knowledge, at present no formal framework is available to evaluate the performance of assistive tools in quantitative terms that are used by visually challenged users to use internet. This research work takes some initiative in this direction by formulating a hierarchical model for quantitative evaluation of assistive tools for blinds. Identifying various Performance Attributes and Usage Metrics, we have established relationship among these to obtain the Overall Performance Index of the assistive tools.

This research work has strengthened our belief that knowledge and technology should be used in favor of mankind to every possible extent. Internet is a wonderful tool having ability to compensate the visual impairment with technology. Design and development of powerful yet affordable speech-based interfaces would be certainly helpful in enhancing the overall Quality of Life of visually challenged. The work done by us shall be further taken up in future e.g. enhancing the features and capabilities of WACTA web browser, its design and development for Android based Tablet Computers as well as extending it for Hindi scripted websites.

ACKNOWLEDGEMENT

I would like to express my deepest gratitude to my Supervisor, Prof. Raghuraj Singh for his guidance and support throughout this research work. His single mindedness, dedication and enthusiasm towards research have constantly inspired me. It has been an honor working with him.

I am thankful to Uttarakhand Technical University, Dehradun for providing me the opportunity and approval to do this research work.

This research is a part of the Major Research Project entitled “Design and Development of Web Browser for Visually Challenged” funded by the University Grants Commission, New Delhi running in Computer Science & Engineering Department of Harcourt Butler Technological Institute, Kanpur during the year 2009 - 2012. I would like to thank the University Grant Commission, New Delhi for extending all the support to realize this work.

I am thankful to Harcourt Butler Technological Institute, Kanpur for providing necessary facilities to complete this research work.

I am thankful to Adult Training Centre, National Institute of Visually Handicap, Dehradun for providing their help and support for the research work.

I am greatly indebted to Prof. Padam Kumar, Professor and Head, Department of Electronics and Computer Engineering, Indian Institute of Technology, Roorkee for his valuable suggestions regarding the principles of good research work.

I am thankful to Prof. Hema A Murthi, Indian Institute of Technology, Chennai for her valuable suggestions regarding the scope of this research work at the very beginning.

Finally, I am thankful to my family members, friends, and colleagues for supporting me directly or indirectly in this work.

(Prabhat Verma)

TABLE OF CONTENTS

CERTIFICATE

Abstract

ACKNOWLEDGEMENT

LIST OF TABLES

LIST OF FIGURES

Chapter 1 Introduction

1.1.Major Objectives

1.2.Domain of the Research

1.3 Research Scope

1.4 A Survey for assessment of User Requirements

1.5 Research Problem Statement

1.6 Proposed Solution

1.7 Organization of Thesis

Chapter 2 Background Work

2.1.Problems and Issues

2.1.1.Accessibility, Usability and Navigability

2.1.2.Keyboard based Accessibility

2.1.3.Role of Web Developers

2.1.4.Role of Assistive Tools

2.1.5.Role of Visually Challenged Users

2.1.6.Various strategies to design the Web Accessibility tools

2.1.7.Universal Vs. Local Installation

2.2.W3C Recommendations on Accessibility

2.2.1.W3C and WAI

2.2.2.WAI Specifications

2.2.3.Web Content Accessibility

2.2.4.Authoring Tool Accessibility

2.2.5.User Agent Accessibility

2.2.6.Accessible Rich Internet Applications Suite

2.2.7.Challenges posed by Web 2.0

2.3.Existing Systems

2.4.Text to Speech (TTS) on Web

Chapter 3 WACTA, the Speech based Web Browser

3.1.INTRODUCTION

3.2.System Design

3.2.1.Conceptual Architecture

3.2.2.Link Navigation Mode

3.2.3.Navigate All Mode

3.2.4.Newsreader Mode

3.2.5.Page Analytics Mode

3.2.6.Query Mode

3.2.7.Text Glimpse through mouse Mode

3.2.8.Switch over among modes

3.2.9.Key Shortcuts

3.2.10.Informed Search

3.3.System Development and Implementation

3.3.1.Platform and Language

3.3.2.NET Framework

3.3.3.The WebBrowser Class

3.3.4.Web Page Analytics

3.3.5.HtmlDocument class

3.3.6.HtmlElement Class

3.3.7.HtmlElementCollection class

3.3.8.SpeechSynthesizer Class

3.3.9.Newsreader style Navigation

3.3.10.Tab based Navigation

3.3.11.Up/Down key based Navigation

3.3.12.Query Mode

3.3.13.Analytical Mode

3.3.14.Text Glimpse Mode

3.3.15.Narrator Voice Management

3.3.16.Speech Feedback for User Inputs

3.3.17.Commands and Key Shortcuts in WACTA

3.4.User Evaluation of WACTA

3.5. CONCLUSIONS

Chapter 4 Direct Speech-enabling the Public Utility Websites

4.1.Introduction

4.2.SYSTEM DESIGN AND ARCHITECTURE

4.2.1.Design Goals and Decisions

4.2.2.The Conceptual Architecture

4.3.Speech enabling public utility websites: Case study of Indian Railways Website

4.3.1.Navigation related issues

4.3.2.Identify the Key functionalities of the website

4.3.3.Speech enabling the Book a Berth functionality

4.4.System Assessment

4.4.1.Results and Discussion

4.4.2.Conclusions

Chapter 5 Voice-XML /VOIP based Client Interface for interactive browsing

5.1.Introduction

5.2.Speech-based Interactive Systems

5.2.1.VoiceXML

5.2.2.GUIs, WUIs, VUIs

5.2.3.W3C recommended Speech Interface Framework

5.2.4.Other Framework for speech Interface

5.3.Design of SICE Framework

5.3.1.Enhanced Functionality

5.3.2.Platform and Language

5.3.3.System Architecture

5.4.Speech based web applications development using SICE Framework

5.4.1.As a Result Checker

5.5.Conclusions

Chapter 6 Performance Evaluation of Internet Assistive Tools

6.1.Defining the Framework

6.1.1.Identification of Performance Attributes

6.1.2.Identification of Usage Properties

6.1.3.Identification of Usage Metrics

6.1.4.Ground Case Values of Usage Metrics

6.1.5.Mapping Usage Properties to Performance Attributes

6.1.6.Formulation for Performance Attributes

6.1.7.Formulation for Overall Performance Measure of Assistive Tool

6.1.8.Using the Framework in Performance Evaluation

6.2.conclusions

Chapter 7 Results and Discussion

7.1.Introduction

7.2.Evaluation Methodology

7.3.Evaluation Results

7.4.Conclusions

Chapter 8 ConclusionS and Future Directions

8.1.INTRODUCTION AND Work summary

8.2.CONTRIBUTIONS OF THE RESEARCH WORK

8.3.Future directions

References

Appendix – I Code for WACTA Web Browser

Bibliography

LIST OF PUBLICATIONS (OUT OF PRESENT RESEARCH WORK)

Curriculum Vitae

LIST OF TABLES

Table 2.1: Accessibility, Usability and Navigability defined from the three perspectives

Table 3.1(i): Properties of WebBrowser Class

Table 3.1(ii): Methods of WebBrowser Class

Table 3.1(iii): Events of WebBrowser class used

Table 3.2(i): Properties of HtmlDocument class used

Table 3.2(ii): Methods of HtmlDocument class used

Table 3.2(iii): Events of HtmlDocument class used

Table 3.3(i): Properties of HtmlElement class used

Table 3.3(ii): Methods of HtmlElement class used

Table 3.3(iii): Events of HtmlElement class used

Table 3.4: Properties of HtmlElementCollection class used

Table 3.5(i): Properties of SpeechSynthesizer class used

Table 3.5 (ii): Events of SpeechSynthesizer class used

Table 3.5(iii): Methods of SpeechSynthesizer class used

Table 3.6: Newsreader Style Navigation

Table 3.7: Tab based Navigation

Table 3.8: Up/Down key based Navigation

Table 3.9: Query mode of WACTA

Table 3.10: Analytic mode of WACTA

Table 3.11: Text Glimpse Mode of WACTA

Table 3.12: Narrator Voice Management in WACTA

Table 3.13: Speech Feedback Management in WACTA

Table 3.14: Lists of Keyboard Commands in WACTA

Table 6.1: Performance Attribute Definitions

Table 6.2: Usage Property Definitions

Table 6.3: Usage Metrics Descriptions

Table 6.4:Mapping of Usage Properties to Performance Attributes

Table 6.5: Formulation for the Performance Attributes

Table 6.6: Equation forOverall Performance Measure

Table 7.1: Test cases to evaluate the WACTA Webbrowser

Table 7.2: User Evaluation Analysis