Harper / Karat / Yesilada Web Accessibility

A Foundation for Research
1. Auflage 2008
ISBN: 978-1-84800-050-6
Verlag: Springer
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 364 Seiten

Reihe: Human-Computer Interaction Series

Covering key areas of evaluation and methodology, client-side applications, specialist and novel technologies, along with initial appraisals of disabilities, this important book provides comprehensive coverage of web accessibility. Written by leading experts in the field, it provides an overview of existing research and also looks at future developments, providing a much deeper insight than can be obtained through existing research libraries, aggregations, or search engines.

Autoren/Hrsg.

Karat, John

Vanderdonckt, Jean

Abowd, Gregory

Calvary, Gaëlle

Carroll, John

Cockton, Gilbert

Cz, Mary

Harper, Simon

Yesilada, Yeliz

Inhaltsverzeichnis

1;Acknowledgments;7
2;Contents;9
3;Contributors;11
4;Introduction;15
5;Part 1: Understanding Disabilities;21
5.1;Visual Impairments;22
5.1.1;1 Introduction: The Physiological Basis of Visual Perception;22
5.1.1.1;1 Formation of the Retinal Image;23
5.1.1.2;1 Neurological Function in the Retina;25
5.1.2;2 Overview: Functional Requirements for Visual Perception;25
5.1.3;3 Discussion: Functionality Restrictions in Visual Disorders;27
5.1.4;4 Approaches to Enhance Human-Computer Interaction;28
5.1.5;5 Emerging Solutions;30
5.1.6;6 Conclusions;31
5.1.7;References;31
5.2;Cognitive and Learning Impairments;34
5.2.1;1 Introduction;34
5.2.2;2 Overview;35
5.2.3;3 Discussion;37
5.2.4;4 Future Directions;39
5.2.5;5 Author’s Opinion of the Field;40
5.2.6;References;41
5.3;Hearing Impairments;44
5.3.1;1 Introduction;44
5.3.1.1;1.3 Models of Hearing Impairment;44
5.3.1.2;1.3 Demographics on Hearing Impairments;46
5.3.1.3;1.3 Legal Perspective;46
5.3.2;2 Deaf People and Sign Language;47
5.3.2.1;2.1 Sign Language;47
5.3.2.2;2.2 Historical Perspective - Education;47
5.3.2.3;2.3 Historical Perspective - Technology;49
5.3.3;3 Current Web Access Technology;50
5.3.3.1;3.1 Embedded Video and Captioning;50
5.3.3.2;3.2 Captioning Services;51
5.3.3.3;3.3 Access Using Sign Language;51
5.3.4;4 Future Research Directions;52
5.3.5;5 Authors’ Opinion of the Field;53
5.3.6;References;54
6;Part 2: Evaluation and Methodologies;78
6.1;Physical Impairment;56
6.1.1;1 Introduction;56
6.1.1.1;1.3 Musculoskeletal Disorders;57
6.1.1.2;1.3 Movement Disorders;58
6.1.1.3;1.3 Prevalence of Dexterity Impairments;59
6.1.1.4;1.3 Co-occurrence of Dexterity and Other Impairments;59
6.1.2;2 Discussion;60
6.1.2.1;2.1 Social and Economic Significance;60
6.1.2.2;2.2 Alternative Input Mechanisms;61
6.1.2.3;2.3 Effect of Dexterity Impairments on Technology and Web Access;61
6.1.3;3 Future Directions;63
6.1.4;4 Author’s Opinion of the Field;64
6.1.5;References;64
6.2;Ageing;66
6.2.1;1 Introduction;66
6.2.2;2 Physical Changes;67
6.2.2.1;2.1 Vision;67
6.2.2.1.1;2.1.1 Age-Related Macular Degeneration (AMD);68
6.2.2.1.2;2.1.2 Cataracts;68
6.2.2.1.3;2.1.3 Presbyopia;69
6.2.2.1.4;2.1.4 Glaucoma;69
6.2.2.2;2.2 Hearing;70
6.2.2.3;2.3 Psychomotor;70
6.2.3;3 Cognitive Changes;71
6.2.3.1;3.1 Attention;71
6.2.3.2;3.2 Memory;72
6.2.4;4 Behavioural Changes;73
6.2.5;5 Author’s Opinion of the Field;74
6.2.6;6 Future Directions;74
6.2.7;References;75
6.3;Web Accessibility and Guidelines;80
6.3.1;1 Introduction;80
6.3.2;2 Overview;82
6.3.2.1;2.1 Device Independence;85
6.3.2.2;2.2 Web Interaction;86
6.3.2.3;2.3 Adaptation and Coping - Key Components of Disabled Interaction;87
6.3.3;3 Discussion;87
6.3.4;4 Future Directions;89
6.3.4.1;4.1 Web Content Accessibility Guidelines (Version 2);90
6.3.4.2;4.2 Internationalisation and Guideline Snow;91
6.3.4.3;4.3 Other Domains and Generalisation;92
6.3.4.4;4.4 Everyone Editing;93
6.3.5;5 Authors Opinion of the Field;94
6.3.6;6 Conclusion;95
6.3.7;References;95
6.4;Web Accessibility Evaluation;98
6.4.1;1 What Is Evaluation?;98
6.4.2;2 Principles of Evaluation;99
6.4.2.1;2.1 Evaluation and Development;100
6.4.2.1.1;2.1.1 Requirements Phase;100
6.4.2.1.2;2.1.2 Design Phase;101
6.4.2.1.3;2.1.3 Implementation Phase;102
6.4.2.1.4;2.1.4 Operation Phase;102
6.4.2.2;2.2 Testing Techniques;103
6.4.2.2.1;2.2.1 Automated Testing;104
6.4.2.2.2;2.2.2 Manual Testing;105
6.4.2.2.3;2.2.3 User Testing;105
6.4.2.3;2.3 Sampling Strategies;106
6.4.2.4;2.4 Evaluation Methodologies;108
6.4.2.4.1;2.4.1 Audit Versus Certification;109
6.4.2.4.2;2.4.2 Example Methodologies;110
6.4.3;3 Practical Considerations;110
6.4.3.1;3.1 Distributing Responsibilities;111
6.4.3.2;3.2 Training Evaluators;112
6.4.3.3;3.3 Selecting and Using Evaluation Tools;113
6.4.4;4 Future Directions;114
6.4.4.1;4.1 Web Applications;115
6.4.4.2;4.2 Web Technologies;117
6.4.4.3;4.3 Web Quality Assurance;117
6.4.5;5 Research and Development;118
6.4.5.1;5.1 Sampling Strategies;119
6.4.5.2;5.2 Measuring Accessibility;120
6.4.5.3;5.3 Tool Integration;121
6.4.6;6 Summary and Conclusions;122
6.4.7;References;124
6.5;End User Evaluations;126
6.5.1;1 Introduction;126
6.5.2;2 Overview;128
6.5.2.1;2.1 Commonly Used Evaluation Paradigms;128
6.5.2.1.1;2.1.1 Performance Measures;128
6.5.2.1.2;2.1.2 Logging User Actions;129
6.5.2.1.3;2.1.3 Questionnaires;130
6.5.2.1.4;2.1.4 Observation;131
6.5.2.1.5;2.1.5 Interviews;132
6.5.2.1.6;2.1.6 Think Aloud;132
6.5.2.2;2.2 Designing an Effective Study;133
6.5.2.2.1;2.2.1 Sampling;133
6.5.2.2.2;2.2.2 Ensuring Validity;134
6.5.2.2.3;2.2.3 Data Analysis;135
6.5.2.2.4;2.2.4 Ethical Treatment of Participants;136
6.5.3;3 Discussion;137
6.5.4;4 Future Directions;138
6.5.5;5 Authors’ Opinion of the Field;141
6.5.6;6 Conclusions;143
6.5.7;References;144
6.6;Authoring Tools;146
6.6.1;1 Introduction;146
6.6.2;2 Overview and History of the Field;147
6.6.3;3 Discussion;149
6.6.3.1;3.1 Encouraging the Creation of Accessible Content;149
6.6.3.2;3.2 Authoring Tools That Are Accessible to People with Disabilities;152
6.6.4;4 Future Directions;153
6.6.4.1;4.1 Rich Internet Applications;153
6.6.4.2;4.2 Individual Optimization or ‘‘One Size Fits One’’;154
6.6.5;5 State of the Field;155
6.6.6;6 Conclusions;156
6.6.7;References;157
7;Part 3: Applications;158
7.1;Assistive Technologies;160
7.1.1;1 Introduction;160
7.1.2;2 A Brief Introduction to Web Technology: HTML;162
7.1.3;3 Tools to Support Accessible Design;168
7.1.4;4 Visual Screen Access;169
7.1.5;5 Accessible Browsing;172
7.1.5.1;5.1 Specialized Browsers;172
7.1.5.2;5.2 Standard Browsers Plus Access Technology;174
7.1.5.3;5.3 Extending the Technology;176
7.1.6;6 Discussion;178
7.1.7;7 Future Directions;178
7.1.8;8 Technology Is Not the Whole Answer;179
7.1.9;9 Conclusions;180
7.1.10;References;181
7.2;Desktop Browsers;182
7.2.1;1 Introduction;182
7.2.1.1;1.3 Testing for Functional Web Accessibility;183
7.2.1.2;1.3 Keyboard Testing;184
7.2.1.3;1.3 Styling;184
7.2.1.4;1.3 Text Descriptions and Conditional Content;186
7.2.1.5;1.3 Browser Impact on Accessibility;187
7.2.2;2 Built-In Features for Accessibility;188
7.2.2.1;2.1 Keyboard Overview;188
7.2.2.2;2.2 Keyboard Shortcuts;188
7.2.2.3;2.3 Styling Content;188
7.2.2.4;2.4 Images;194
7.2.2.5;2.5 Conditional Content;196
7.2.2.6;2.6 Scripting;196
7.2.2.7;2.7 Device Independence and Event Handlers;197
7.2.2.8;2.8 Pop-Up Windows;198
7.2.2.9;2.9 Embedded Objects;199
7.2.2.10;2.10 Configuration;200
7.2.3;3 Extending Browser Functions;201
7.2.3.1;3.1 Making Conditional Content Visible;202
7.2.3.2;3.2 Enhancing Keyboard Support;203
7.2.3.3;3.3 Styling;203
7.2.3.4;3.4 Other Features;203
7.2.4;4 Compatibility with Assistive Technologies;204
7.2.4.1;4.1 Document Object Model;204
7.2.4.2;4.2 Accessibility APIs;205
7.2.5;5 Accessible Rich Internet Applications (ARIA);205
7.2.5.1;5.1 TABINDEX and Keyboard Focus;206
7.2.5.2;5.2 Roles, Properties, and States;206
7.2.5.3;5.3 Accessibility API Support;210
7.2.6;6 Conclusions;210
7.2.7;7 Additional Resources;210
7.2.7.1;7.1 W3C Recommendations and Other Standards;211
7.2.7.2;7.2 Accessibility Extensions;211
7.2.7.3;7.3 Accessibility APIs;211
7.2.8;References;212
7.3;Specialized Browsers;214
7.3.1;1 Introduction;215
7.3.2;2 Overview;215
7.3.2.1;2.1 Talking Browsers-1994-1998;216
7.3.2.2;2.2 Spoken Web Access-1998-2003;217
7.3.2.3;2.3 Spoken Web Access-2003-Present;217
7.3.2.4;2.4 Voice Browsers-2000-2007;218
7.3.3;3 Access Guidelines;219
7.3.3.1;3.1 Content Is King;220
7.3.3.2;3.2 Separation of Content from Style;220
7.3.3.3;3.3 Separation of Content and Interaction;221
7.3.4;4 Future Directions;222
7.3.4.1;4.1 Web Wizards and URL Templates;222
7.3.4.2;4.2 Portals and Web Gadgets;224
7.3.4.2.1;4.2.1 Portlets and Portal Servers;224
7.3.4.2.2;4.2.2 Web Gadgets;225
7.3.4.3;4.3 Web APIs and Mashups;226
7.3.4.4;4.4 Putting It Together-Ubiquitous Access;227
7.3.4.4.1;4.4.1 Web Command-Line;228
7.3.4.5;4.5 Web Access-A Personal View;229
7.3.4.5.1;4.5.1 Speech-Enabling Dynamic User Interfaces;230
7.3.5;5 Summary;231
7.3.6;References;232
7.4;Browser Augmentation;234
7.4.1;1 Introduction;234
7.4.2;2 Overview;235
7.4.3;3 Browser Extension Mechanisms;236
7.4.3.1;3.1 Internet Explorer;236
7.4.3.1.1;3.1.1 Style Sheets;236
7.4.3.1.2;3.1.2 Browser Objects;237
7.4.3.2;3.2 Mozilla Firefox;239
7.4.3.2.1;3.2.1 Extensions;240
7.4.3.2.2;3.2.2 Style Sheets;241
7.4.3.2.3;3.2.3 Themes;241
7.4.3.2.4;3.2.4 Plugins;241
7.4.3.3;3.3 Other Browsers;241
7.4.3.3.1;3.3.1 Safaritm;241
7.4.3.3.2;3.3.2 Operatm;242
7.4.3.4;3.4 Impact of Browser Implementation Details;243
7.4.4;4 Future Directions;245
7.4.5;5 Our Opinion of the Field;246
7.4.6;6 Conclusions;247
7.4.7;References;247
7.5;Transcoding;250
7.5.1;1 Introduction;250
7.5.2;2 Methods;257
7.5.2.1;2.1 Text Magnification;258
7.5.2.2;2.2 Color Scheme Changes;258
7.5.2.3;2.3 Serialization;258
7.5.2.4;2.4 Alternative Text Insertion;259
7.5.2.5;2.5 Page Rearrangement;260
7.5.2.6;2.6 Simplification;262
7.5.3;3 Architectures;263
7.5.4;4 Techniques;266
7.5.4.1;4.1 Annotation-Based Transcoding;266
7.5.4.1.1;4.1.1 Simplification Based on Differential Analysis;271
7.5.5;5 Future Directions;272
7.5.5.1;5.1 Transcoding for Dynamic Contents;272
7.5.5.2;5.2 Revival of Intermediary Approach;274
7.5.6;6 Conclusions;275
7.5.7;References;275
8;Part 4: Specialised Areas;280
8.1;Education;282
8.1.1;1 Introduction;282
8.1.2;2 Overview;283
8.1.3;3 Discussion;284
8.1.3.1;3.1 Learning Objects: Package and Metadata;285
8.1.3.2;3.2 Developing Accessible E-Learning Content and Applications;286
8.1.3.3;3.3 E-Learning Content Customization;286
8.1.3.4;3.4 Projects;287
8.1.4;4 Future Directions;288
8.1.5;5 Authors Opinion of the Field;288
8.1.6;6 Conclusions;289
8.1.7;References;290
8.2;Specialized Documents;292
8.2.1;1 Types of Specialized Documents;292
8.2.2;2 Sources of Accessibility Problems;298
8.2.3;3 Improving Accessibility;300
8.2.4;4 Summary;303
8.3;Multimedia and Graphics;306
8.3.1;1 Introduction;306
8.3.2;2 Overview;307
8.3.3;3 Discussion;308
8.3.3.1;3.1 Standards and Specifications;308
8.3.3.2;3.2 Assistive Technology;310
8.3.3.3;3.3 User Testing;311
8.3.3.4;3.4 Text-Only Sites;311
8.3.3.5;3.5 Separating Presentation from Structure;312
8.3.3.6;3.6 Separating Presentation from Structure in Video;313
8.3.4;4 Future Directions;313
8.3.5;5 Authors’ Opinion of the Field;316
8.3.6;6 Conclusion;317
8.3.7;Resources;317
8.3.8;References;318
8.4;Mobile Web and Accessibility;320
8.4.1;1 Introduction;320
8.4.2;2 Going Beyond Perceivability;322
8.4.3;3 Design Perspectives for Cognitive Accessibility and Usability;323
8.4.3.1;3.1 Distinction Between Perceiving and Understanding;325
8.4.3.1.1;3.1.1 Specifying the Object;325
8.4.3.1.2;3.1.2 Specifying the Action;325
8.4.3.1.3;3.1.3 Assessing the Outcome;326
8.4.3.2;3.2 Forming the Intention;327
8.4.3.3;3.3 Action Slip;327
8.4.4;4 Lessons Gained from Web Accessibility and Their Implications for Mobile Web;328
8.4.4.1;4.1 Explicit Perceptual-Cognitive Distinction;328
8.4.4.2;4.2 Scenario-Based Evaluation;329
8.4.4.3;4.3 Remote Testing;330
8.4.5;5 Conclusions;331
8.4.6;References;331
8.5;Semantic Web;334
8.5.1;1 Introduction;334
8.5.2;2 Background;335
8.5.3;3 The Web Ontology Language OWL;337
8.5.3.1;3.1 Description Logic;337
8.5.4;4 Ontology Reasoning;340
8.5.4.1;4.1 Reasoning at Design Time;340
8.5.4.2;4.2 Reasoning in Deployment;341
8.5.5;5 Ontology Applications;341
8.5.6;6 Semantics and Accessibility;342
8.5.6.1;6.1 End-User Applications;342
8.5.6.2;6.2 Support Tools;343
8.5.6.3;6.3 Annotation for Accessibility;343
8.5.7;7 Future Directions;344
8.5.8;8 Conclusions;346
8.5.9;References;346
8.6;Web 2.0;350
8.6.1;1 Introduction;350
8.6.2;2 Overview;351
8.6.2.1;2.1 Web 2.0 Becomes Mainstream;351
8.6.2.2;2.2 Web 2.0 and Accessibility Concerns;352
8.6.2.2.1;2.2.1 Scripting and CSS;352
8.6.2.2.2;2.2.2 Updating Data;353
8.6.2.2.3;2.2.3 Organizing Data;353
8.6.2.2.4;2.2.4 Abundance of Data;354
8.6.3;3 Discussion;354
8.6.3.1;3.1 Provide Simple Navigation;354
8.6.3.2;3.2 Manage Focus Appropriately;355
8.6.3.3;3.3 Use Semantic Markup;356
8.6.3.4;3.4 Provide Clear Instructions;356
8.6.4;4 Future Directions;357
8.6.4.1;4.1 Accessibility Guidelines;357
8.6.4.2;4.2 Accessible Rich Internet Applications (ARIA);358
8.6.4.2.1;4.2.1 Providing Additional Semantics;358
8.6.4.2.2;4.2.2 Full Keyboard Support;359
8.6.4.2.3;4.2.3 Incremental Updates and Live Regions;359
8.6.4.3;4.3 IAccessible2 Interface;360
8.6.5;5 Author’s Opinion of the Field;360
8.6.6;6 Conclusions;361
8.6.7;References;362
8.7;Universal Usability;364
8.7.1;1 Introduction: The Elements of Universal Usability;364
8.7.1.1;1.1 Universal Access;365
8.7.1.2;1.1 Usability;366
8.7.1.3;1.1 Universal Design;366
8.7.2;2 Factors Supporting Universal Usability;367
8.7.2.1;2.1 Web Technology;367
8.7.2.2;2.2 User-Centered Design;368
8.7.2.3;2.3 Policies;368
8.7.3;3 Universal Design and the Web;369
8.7.3.1;3.1 Universal Design Principles;369
8.7.4;4 Authors’ Opinion of the Field;371
8.7.5;5 Future Directions;372
8.7.6;6 Conclusions;372
8.7.7;References;373
9;Index;376