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Just-in-Time Information Propagation (WebVigiL)


Data on the web is constantly increasing. Many a times, users are interested in specific changes to the data on the web. Currently, in order to detect changes of interest, users have to poll the pages and check for the changes he/she is interested in. Efficient and effective change detection and notification is critical in many environments where a lot of resources are wasted in monitoring changes to the web manually. WebVigiL is a change monitoring system, which efficiently monitors changes to the page on behalf of the user and notifies the changes in a timely manner. It handles the specification, management, and propagation of changes as requested by a user while meeting the quality of service requirements.


WebVigiL is a change detection and notification system detect changes to structured\unstructured documents. Use of a new paradigm for monitoring information to structured documents. The current work addresses HTML/XML documents. WebVigiL objectives: i) Adapt and use previous work on active capability ii) Investigate user specification/profiles iii) management and propagation of changes in a timely manner, iv) meeting quality of service requirements ,v) Efficient and effective change detection and notification


The proposed system - termed WebVigiL provides a powerful way to disseminate information efficiently without sending unnecessary or irrelevant information. It also frees the user from having to constantly monitor for changes using the pull paradigm. Active rules have been proposed as a paradigm to satisfy the needs of many database and other applications that require a timely response to situations. Event-Condition-Action (or ECA) rules are used to capture the active capability in a system. The utility and functionality of active capability (ECA rules) has been well established in the context of databases. In order for the active capability to be useful for a large class of advanced applications, it is necessary to go beyond what has been proposed/developed in the context of databases. We believe that some of the techniques developed for active databases, when extended appropriately along with new research extensions will provide a solution to the above class of problems. Read more




WebVigiL is supported, in part by,

  • The Office of Naval Research
  • The SPAWAR System Center-San Diego
  • The Rome Laboratory (grant F30602-01-2-05430),
  • and by, NSF (grant IIS-0123730)

Department of Computer Science and Engineering