A framework for building web sites that are friendly to visually impaired
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The document outlines the critical need for web accessibility, particularly for visually impaired users, highlighting various social, business, and legal factors that necessitate compliance. It discusses the importance of developing and evaluating web accessibility tools and guidelines to optimize user experience for diverse audiences, including the differently-abled and seniors. A specialized solution, the Web Accessibility Generator, is proposed to facilitate web content accessibility through prioritization of features according to disability needs and implementation strategies.
A framework for building web sites that are friendly to visually impaired
- 2. Line up Web Visual Accessibility Impairments THE NEED State of the Art New Tool in NEW SOLUTION Action
- 3. Web Accessibility “The power of the Web is in its universality... Access by everyone regardless of disability is an essential aspect…” Tim Berners-Lee Yet, Web is primarily meant for visual consumption which makes accessibility barrier for visually impaired users.
- 4. NEED FOR ACCESSIBILITY • Social factors • Business factors • Legal and policy factors Making even grounds Winning the market Conforming to the law
- 5. Complete the markets by serving chronically underserved • Differently abled people • Senior population • Less experienced web users • Illiterate • Consumers of low bandwidth connections • Mobile users
- 6. Investment on web accessibility pays back!! • Better treated by search engines • Exposition of corporate social responsibility • Reduced legal risk • Increased customer loyalty
- 7. Visual Impairments • No Perception of Light (NPL) Total • Require an audio presentation of information Blind • Weak visual acuity to light perception or deficient visual field Low • Require magnifying and color contrast techniques and audio Vision • A deficiency or absence in the photosensitive cells in the eye • Require alternatives to present information associated with Color colors blind
- 8. Low Vision Total Blind 285 million people 14% are visually impaired worldwide 86% In developing countries Aged 50 and older In developed countries Others 10% 35% 65% 90%
- 9. Why need accessibility evaluation and authoring tools? • Require expertise Components of Web Accessibility • Time and labor intensive • Lack of experience Source: http://www.w3.org/WAI/intro/components.php
- 10. Existing Support Web Content Accessibility Guidelines Web Accessibility Initiative – Widely accepted Accessible Rich Internet Applications Up to date A technical specification User agents and AT conform Describe roles, states, and Generic and technology neutral properties for custom widgets Well structured and classified Notify dynamic contents properly
- 11. Solution Specialization in achieving accessibility for visually impaired Overview Evaluation based on priority and visual impairment type Providing guidelines and methods to implement accessibility features A platform independent solution (OS, Browser agnostic) Familiar development environment + An extensible framework Web Accessibility Generator
- 12. Web accessibility features specification Text alternatives, captions and other Make all functionality available alternatives from a keyboard Adaptable: present in simpler layouts Provide enough time to read and Distinguishable: make it easier to see use content and hear content Easy navigation Perceivable Operable Web Accessibility Features Understandable Robust Make text readable and understandable Maximize compatibility with Help users avoid and correct mistakes variety of user tools
- 13. Rules selection criteria • Rules that must be satisfied. Level C Unless satisfying them the High content is inaccessible. High priority • Rules that should be satisfied. Unless satisfying them the Level B Medium content can be accessible with difficulties. High + Medium priority • Rules that are good to be Level A satisfied. Unless they are Low satisfied, accessing the content High + Medium + Low may be somewhat difficult. priority
- 14. Rules corpus Priority Disability 1. Text alternative for images High TB + LV + CB 2. Text or audio alternative for videos High TB + LV + CB 3. Text description for color cues and phrase elements High TB + LV + CB 4. Caption and summary for data tables High TB + LV 5. Paragraphs instead of data tables Medium TB + LV 6. Proper labeling for form controls High TB + LV 7. Enhanced visual presentation of text Medium LV + CB 8. Contrast color for visual cues Medium LV + CB 9. Keyboard control for all functionality High TB + LV 10. Bypass repeated content High TB + LV 11. Meaningful page title High TB + LV 12. Purposeful link text High TB + LV 13. List of content Medium TB 14. Sequential navigation Medium TB 15. Definitions for the unusual words Medium TB + LV 16. Explanations for abbreviations Low TB + LV 17. Input assistant using ARIA properties low TB + LV 18. Tab order to receive focus High TB + LV
- 15. Use case diagram Open source file Select scan criteria and scan Display accessibility violations list Select an accessibility violation Highlight in code & show details WAG system Fix or Skip the violation Apply changes Update list & progress bar Deploy the modified source Render the new web page
- 16. System Design
- 18. Object diagram Rule Feature Result title id violations array disability_rank feature priority element description line evaluate (xml code) solution status {} rule resetLine () {} setStatus () {} Report Scanner results issues total: 0 priority resolves: 0 disablity_rank skips: 0 Scan () {} Create () {} Filter () {} Update () {}
- 19. Data Model • Accessibility feature Knowledgebase • Applicable disability • Priority level API • Error message • Description • Solution
- 20. Scan criteria ( Feature Valid = Priority_valid && DisabilityRank_valid ) Disability Rank = Selected Feature Product of ranks of each Validity applicable disability priority priority A (3) High (1) True A (3) Medium (2) True Selected Valid ranks of features A (3) Low (3) True disability rank B (2) High (1) True 2 2, 6, 10, 30 B (2) Medium (2) True (Total Blind) B (2) Low (3) False 3 3, 6, 15, 30 C (1) High (1) True (Low Vision) C (1) Medium (2) False 5 5, 10, 15, 30 C (1) Low (3) False (Color Blind)
- 26. Future Work • Extend support for DHTML • Add support for assistive devices • Autocorrection
- 27. Thanks !
Editor's Notes
- #2: An inclusive framework for building accessible websites for visually impaired users.
- #4: The Web is an increasingly important resource in many aspects of life: education, employment, government, commerce, health care, recreation, and more.Simply WA means the ability to use web by disable ppl and contribute like normal ppl. As a universal medium the web is necessary to be accessible in order to provide equal opportunity to people with disabilities. Since today’s Rich Internet Applications (RIA) are primarily meant for visual consumption, accessing Web content has become one of the main deprivations for millions of visually impaired users..
- #5: (UN) Convention on the Rights of Persons with Disabilities (2006) recognizes web accessibility as a basic human rightIndirectly it benefits to elder people and people with low literacy. Furthermore the accessible web sites are more usable to people with low bandwidth connections, mobile web users and infrequent web users as well.In business perspective,exposition of corporate social responsibility (CSR), reduced legal risk and increased customer loyalty. For these reasons the costs of implementing web accessibility pays back with substantial return on investment (ROI) at the endVarious laws, policies and regulations enforced by governments and other organizations have formed the legal requirements to enable the web accessibility.
- #9: •285 million people are visually impaired worldwide and 90% of them live in developing countries. All visual impairments fall into two main categories, total blindness and low vision. Statistically 39 million people (14%) are blind and 246 million people (86%) have low vision. •About 65% of all people who are visually impaired are aged 50 and older. With an increasing elderly population, more people will be at risk of age-related visual impairment. •1.4 million Children are irreversibly blind for the rest of their lives. This indicates that their vision cannot be healed by any means of existing medical treatments.
- #10: Much of the focus on web accessibility has been on the responsibilities of web developers. Accessible web development is an inclusive practice that requires expertise on the domain and the undertaking is time consuming. Many web developers may lack experience to apply the available accessibility guidelines in their web sites without special assistance [9]. Therefore the web authoring tools and evaluation tools should play a significant role in assisting web developers to achieve accessibility.
- #12: The Web Accessibility Generator software tool basically helps Web developers to evaluate Websites and detect accessibility issues and subsequently apply accessibility features to resolve those issues using provided guidelines. In the first phase of the project a specification is defined based on the standard accessibility requirements in the second phase the web based system is constructed based on the defined specification.
- #13: Perceivable - Information and user interface components must be presentable to users in ways they can perceiveOperable - User interface components and navigation must be operable.Understandable - Information and the operation of user interface must be understandable.Robust- Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies.This is about making a website much more simpler than it is
- #14: High level – these are most important and basic requirements that must be achieved to make a Website accessible to visually impaired users. The high priority rules are essential to ensure the accessibility. Medium level – these are requirements that will enhance the usability with original content. These rules will enhance the usability with original content. Low level – these requirements will provide additional support with more information than original content. These rules provide a supplementary solution to improve the accessibility.
- #15: // TB = Total Blind// LV = Low Vision// Color Blind
- #17: The design of the tool adapts the Model-View-Controller (MVC) architecture. The Rule engine and Knowledge base are the most significant components which are based on the rules described in the previous section.
- #18: The tool is intended to work as a platform and browser independent local web application. Therefore it adapts mainly the cross-browser technologies like Javascript, HTML5 and XML related technologies.
- #20: A standard Knowledge base API is defined in such a manner that it can be extended with much more accessibility features supplied by external databasesThe created data models are defined in XML hence those can be easily accessed using Ajax and get all necessary information regarding a particular accessibility feature.
- #21: Priority validity :(scan_criteria.priority >= feature.priority )Disability rank validity :(scan_criteria.rank).each {If (( feature.rank % scan_criteria.rank ) == 0) return true; }