Dartmouth Solar

A Scalable Context-Fusion Network for Pervasive Computing

solar@cs.dartmouth.edu

Solar has been deployed as a sensor data dissemination middleware in the Automated Remote Triage and Emergency Management Information System(ARTEMIS) project since the summer of 2003. We find that these mission-critical applications need 1) real-time monitoring services (in the form of trigger-based continuous queries) and 2) analytical probing services (in the form of one-shot queries based on historical sensor data as well as real-time sensor streams).

In emergency-response scenarios, solar disseminates high-volume data streams to multiple remote command-and-control applications, via a low-bandwidth wireless mesh network formed by the nodes embedded in fire trucks, police cars and ambulances on the scene. There is a clear disparity between highly-constrained network bandwidth and high-resolution data acquisitional needs of the applications. Thus, for bandwidth efficiency, we propose a "group-aware stream filtering" approach, used together with multicasting, that exploits two overlooked, yet important, properties of monitoring applications: 1) many of them can tolerate some degree of ``slack'' in their data quality requirements, and 2) there may exist multiple subsets of the source data satisfying the quality needs of an application. We can thus choose the ``best alternative'' subset for each application to maximize the data overlap within the group to best benefit from multicasting. Proving the group-aware filtering problem NP-hard, we provide a general framework with a suite of heuristics-based algorithms that ensure data quality (specifically, granularity and timeliness) while preserving bandwidth. Our evaluation based on real-world data traces shows that quality-managed group-aware filtering is effective in trading CPU time for bandwidth savings, compared with self-interested stream filtering.

• David Kotz (Professor)
• Ming Li (Ph.D. Student)
• Alumni
  • Kazuhiro Minami (Ph.D., 2006)
  • Guanling Chen (Ph.D., 2004)
  • Jue Wang(M.S., 2004)
  Lin Zhong (Master Student)
  • Cal Newport (Undergrad, 2004)
  • Adrian Hartline (Undergrad, 2003)
  • Chris Masone (Undergrad, 2002)
  • Abe White (Undergrad, 2002)
  • Arun Mathias (Undergrad, 2001)

Guanling Chen and David Kotz. Solar: An open platform for context-aware mobile applications (short paper). In Proceedings of the First International Conference on Pervasive Computing (Pervasive 2002), pages 41-47, Zurich, Switzerland, June 2002.