Computer Science Colloquium
From TimeSync to EmStar: What's really hard in sensor networks?
Monday, April 26, 2004 11:30 A.M.
Room 1302 Warren Weaver Hall
251 Mercer Street
New York, NY 10012-1185
Colloquium Information: http://cs.nyu.edu/csweb/Calendar/colloquium/index.html
Richard Cole firstname.lastname@example.org, (212) 998-3119
Recent advances in miniaturization and low-cost, low-power design have
led to active research in large-scale networks of small, wireless,
low-power sensors and actuators. Sensor networks have enormous
potential, but their design is challenging in many unexpected ways.
Our research started out in time synchronization -- an important
service in any distributed system, but particularly crucial in sensor
networks. We developed and implemented several new approaches that
better support the unique requirements of this domain. For example,
Reference-Broadcast Synchronization achieves high precision at
low energy cost by leveraging the broadcast property inherent to
wireless communication. A new multi-hop algorithm allows RBS
timescales to be federated across broadcast domains.
When the time came to apply these new methods to academic and
commercial systems that needed synchronization, we learned many
interesting lessons. Perhaps most surprising: in sensor networks,
applications that, on the surface, might seem to hinge on problems
like time synchronization actually were hard for completely different
Based on this experience, we developed EmStar, a software framework
for sensor networks. EmStar's goal is to make the hardest problem
easier: writing software for an environment that is inherently
unpredictable, dynamic, difficult to model, hard to observe, and
always subject to Murphy's Law.
Dr. Jeremy Elson is a post-doctoral researcher at University of
California, Los Angeles, in the Center for Embedded Networked Sensing.
He received his Ph.D. (UCLA, 2003), M.S. (University of Southern
California, 2000), and B.S. (Johns Hopkins University, 1996), all in
Computer Science. Dr. Elson's dissertation work on time
synchronization in low-power wireless sensor networks, advised by
Prof. Deborah Estrin, earned the Edward K. Rice Outstanding Graduate
Student award. His other research interests include operating system
issues and programming models in distributed, self-organizing
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