Wednesday December 06th, 2006
CSE Room 305
12:00 - 1:00 PM
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Analysis of tree-based aggregation techniques in sensor networks |
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Laukik Chitnis |
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The potential gains of deploying sensor networks for large scale
applications are being realized. One of the basic operations in sensor
networks is in-network aggregation. Among the various approaches to
in-network aggregation, such as tree - including the hash-based
techniques - and gossip, the tree-based approaches have better
performance and energy-saving characteristics. However, due to
significant constraints on the cost, and therefore the quality of
sensor motes, and the often hostile environments in which they are
deployed, sensor networks are prone to failures. Numerous techniques
suggested in literature to counteract the effect of failures have not
been analyzed in depth. In this paper, we focus on the performance of
these tree-based aggregation techniques in the presence of failures.
First, we identify a fault model that captures the important failure
traits of the system. Then, we analyze the correctness of simple tree
aggregation with our fault model. The impact of techniques for
maintaining the correctness under faults, such as rebuilding or
locally fixing the tree, is then studied under the same fault model.
We then use the same fault model to analyze the techniques that
utilize redundant trees to improve the variance. We also do the
cost-benefit analysis of using hash-based schemes based on FM
sketches.
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