DTS: Dartmouth Theory Seminars - Winter 2005

Winter 2005 Schedule

Jan 7 (Friday) Gopal Pandurangan, Purdue University
The Bin-Covering Technique for Thresholding Random Geometric Graph Properties
Room: Moore B03 (tentative)
Time: 4pm - 5pm.


Abstracts

Gopal Pandurangan, Purdue University
The Bin-Covering Technique for Thresholding Random Geometric Graph Properties

We study the emerging phenomenon of ad hoc, sensor-based communication networks. The communication is modeled by the random geometric graph model G(n,r,l) where n points randomly placed within [0,l]d form the nodes, and any two nodes that correspond to points at most distance r away from each other are connected. We study fundamental properties of G(n,r,l) of interest: connectivity, coverage, and routing-stretch. Our main contribution is a simple analysis technique we call bin-covering that we apply uniformly to get first known, (asymptotically) tight thresholds for each of these properties. Typically, in the past, random geometric graph analyses involved sophisticated methods from continuum percolation theory; on contrast, our bin-covering approach is discrete and very simple, yet it gives us tight threshold bounds. The technique also yields algorithmic benefits as illustrated by a simple local routing algorithm for finding paths with low stretch. Our specific results should also prove interesting to the networking community that has seen a recent increase in the study of geometric random graphs motivated by engineering ad hoc networks.

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