Fulcrum An Open-Implementation Approach to Context-Aware Publish / Subscribe

Robert T. Boyer and William G. Griswold
June 8, 2004

Content-based publish / subscribe (CBPS) systems are a natural substrate for context-aware applications because they provide the right separation of concerns, efficient event distribution, extensibility, and scalability. However, the separation of concerns afforded by CBPS middleware precludes publishers from collaborating with each other to efficiently detect context-aware conditions for publication as events. We overcome this problem with an open implementation approach, which enables subscribers to attach a domain-specific implementation strategy to their context-aware subscriptions. Strategies are supported by first-class active subscriptions that can deploy lower-order dynamic publisher / publisher cross-subscriptions where events enter the CBPS system. By exchanging data on an as-needed basis, event traffic can be dramatically reduced. Our algorithm for detecting the proximity of mobile buddies reduces event traffic from O( |events| ) to O( |movement| ) worst case, O( lg2|movement| ) expected. Experiments reveal an 82% reduction with current positioning technologies.

How to view this document

The authors of these documents have submitted their reports to this technical report series for the purpose of non-commercial dissemination of scientific work. The reports are copyrighted by the authors, and their existence in electronic format does not imply that the authors have relinquished any rights. You may copy a report for scholarly, non-commercial purposes, such as research or instruction, provided that you agree to respect the author's copyright. For information concerning the use of this document for other than research or instructional purposes, contact the authors. Other information concerning this technical report series can be obtained from the Computer Science and Engineering Department at the University of California at San Diego, techreports@cs.ucsd.edu.

[ Search ]

This server operates at UCSD Computer Science and Engineering.
Send email to webmaster@cs.ucsd.edu