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Anita W. Huang, Neel Sundaresan Presented by Allan Spale – EECS 578

Aurora: A Conceptual Model for Web-content Adaptation to Support the Universal Accessibility of Web-based Services. Anita W. Huang, Neel Sundaresan Presented by Allan Spale – EECS 578. Introduction. The World Wide Web is a place for information and commerce

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Anita W. Huang, Neel Sundaresan Presented by Allan Spale – EECS 578

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  1. Aurora: A Conceptual Model for Web-content Adaptation to Support the Universal Accessibility of Web-based Services Anita W. Huang, Neel Sundaresan Presented by Allan Spale – EECS 578

  2. Introduction • The World Wide Web is a place for information and commerce • Electronic information distribution removes previous accessibility barriers • Flexible presentation of information • The use of HTML on web pages removes its meaning and functionality

  3. Problems Using HTML • Makes “comprehension, navigation, and input difficult or completely impossible” • Literal content • Services

  4. Improving Web Accessibility • Low-level accessibility • Provide alternatives to different media types • High-level accessibility • Make Web services in a service domain accessible to a large audience

  5. Description of Aurora • Aurora provides high-accessibility • Analyzes web objects according to their functions within a particular domain of Web pages • Based on a transaction model • Provides a framework for encapsulating general goals within a service domain • “[P]rovides a set of schemas that describes how a user obtains the identified services”

  6. Transaction Model and XML • Converts web data in service domains into XML • XML data is input to interface adaptors • Each interface adaptor creates the new Web page

  7. User Scenario • Blind user visits an on-line auction site • Semantic obstacles appear on the page to “hide” information necessary to make a bid • Aurora can improve this situation • Access the site using Aurora • Aurora will render the page in a format acceptable to the user

  8. Electronic Information Accessibility • Web Accessibility • “…add provisions to existing Web pages.” • Focus on low-level issues • Provide alternate presentation forms for different electronic media

  9. Electronic Information Accessibility • Adaptive Hypermedia • Offers adaptive measures for “new Web-based information systems” • Challenges • Incorporating each user’s goals into a user model • Structuring of information to permit translation across presentation formats

  10. Electronic Information Accessibility • Wrapper generation • Wrapper applications have two roles • Extract information from data • Reorganize the data into structured forms

  11. Aurora’s Transaction Model • Specifies the user’s abstract goals • “Scrapes” information from the Web page relevant to the user goals • Relevant to a specific service domain • Common services • Sequences of tasks to receive services • Declaration of specific steps to accomplish tasks

  12. Transaction Model Specifics • Services • Analyze a service domain to determine “a discrete, common set of abstract user goals” • Transactions • Tasks to be done to receive a service

  13. Transaction Model Specifics • Task Hierarchical Work-Flow Model • Create a node for each step • Connect the nodes according to sequences of steps • Label transitions between nodes where appropriate

  14. Web Content Classification • Transaction model tracks each page’s function in relation to the user goal • Model applies to sets of web pages • Transaction model used to transform content without altering Web pages • Can provide additional structure to data at the source

  15. Benefits for Universal Usability • Consistency • Currently web sites differ in many ways from one another • Transaction model reduces this problem • Consistent interface • “[M]odel specifies a common set of goal-orientated transactions for each service domain”

  16. Benefits for Universal Usability • Simplicity • Web pages usually contain some irrelevant information in relation to user goals • Solution • “Scrape” information from the Web page according to the transaction model that encapsulates the user goal

  17. Benefits for Universal Accessibility • Adaptability • Semantic information is implicit according to its appearance • Solution • Use a transaction model to extract functional semantics and add semantic markup • Interface adaptors take output from transaction model to create presentations for a user group

  18. XML Framework • eXtensible Markup Language used for creating structured data • The transaction model that maps web objects can be stored using a DTD (Document Type Definition) • XML data will maintain the functional semantics which will allow interface adaptation

  19. Using DTDs for Translation Schemas • Describe abstract tasks for every service goal • Contains the semantics and sequence of task steps • Together with the “scraped” web page data, Aurora can write the transaction document in XML

  20. Operation of AuroraUsing XML • User requests a Web page • Aurora downloads Web page and recreates the page • Downloads the web page • Extracts information and objects • Creates XML document using a DTD • Aurora uses the interface adaptor on the XML document to create the new HTML page

  21. Example of User-Aurora Interaction • User views Aurora-generated Web page of an auction site converted from XML to be displayed in HTML • This is a node in the current transaction document • Current node is the item for bidding • Hyperlinks in the generated HTML page lead to other nodes in the XML document

  22. Example of User-Aurora Interaction • User selects a hyperlink • Each XML hyperlink will link to a Web page and a transformation rule • Aurora will download the web page and apply the transformation rule • A hyperlink links to a downloaded HTML document and the extracted XML segment

  23. Example of User-Aurora Interaction • Present the downloaded page to the user • XML segment serves as input to the interface adaptor • Aurora will use the XML segment as input to the interface adaptor • The result is a displayable web page typically in HTML • The process repeats for future interactions

  24. Aurora’s Method ofContent Extraction • Uses PatML * XML transformation tool that…match[es] and transform[s] patterns in XML documents • Three parts to a PatML transformation rule * XML pattern to match (source) * Way to transform the matched pattern (target) * Java code block to invoke on the pattern (action) *Items quoted directly from the paper

  25. Aurora’s Method ofContent Extraction • A transaction step has one PatML rule • This rule will be used for all pages on a single Web site • Three parts of PatML rule, specifically • Source: matches HTML tag patterns • Target: turns matched part into an XML part • Action: gets the XML part and returns its output

  26. Aurora Architecture UsingWeB Intermediaries (WBI) • “…enables applications to manipulate HTTP streams during a Web transaction.” • Three components • Request editor • Interface adaptor translates user actions • Document generator • Downloads web pages, applies transformation rules to web pages, returns XML parts • Document editor • Interface adaptor adapts requested Web pages

  27. Extensible Architecture • Interface Adaptors • “[S]ends XML data and receives user responses.” • Transforms XML data into a low-level presentation format • DTDs used to help generate additional semantic meaning • Two types of adaptors • HTML text-only, Icon-enhanced HTML

  28. Extensible Architecture • Service Domains and Web Sites • XML configuration document stores all service domain definitions • Adding new domains or sites into a domain only involves editing the XML document • Transcoding Engine • Aurora can use other “transcoding and/or extraction technologies” • Currently uses PatML within its transformer interface

  29. Implementation Details • Java plug-in for “WBI using PatML as the transcoding tool” • Schemas include auction and search engine service domains • PatML rules written for specific sites • Auctions: eBay, Yahoo! Auctions • Search Engines: AltaVista, Yahoo!, Google • Uses previously mentioned interface adaptors

  30. Summary • Transaction Model • Extracts semantics of web sites within selected service domains • Uses XML to maintain structured data from Web pages • Semantic Transcoding System • “Scrapes” and adapts web pages to help the user accomplish abstract goals within an XML framework

  31. Summary • Extensible Structure • Supports custom adapters that convert XML data into some presentation format • Improvements • Needs “to support semi-automated or automated rule generation and maintenance”

  32. Resources • XML 1.0 • http://www.w3c.org/TR/REC-xml • Web Content Accessibility Guidelines 1.0 • http://www.w3c.org/wai-webcontent • PatML • http://www.alphaworks.ibm.com/aw.nsf/techmain/00ADAB375888BDD2882566F300703F7F?OpenDocument • WeB Intermediaries (WBI) Development Kit • http://www.almaden.ibm.com/cs/wbi/doc

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