Showing papers by "Samir R. Das published in 2003"

Ad hoc On-Demand Distance Vector (AODV) Routing

Abstract: The Ad hoc On-Demand Distance Vector (AODV) routing protocol is intended for use by mobile nodes in an ad hoc network. It offers quick adaptation to dynamic link conditions, low processing and memory overhead, low network utilization, and determines unicast routes to destinations within the ad hoc network. It uses destination sequence numbers to ensure loop freedom at all times (even in the face of anomalous delivery of routing control messages), avoiding problems (such as "counting to infinity") associated with classical distance vector protocols.

Connected sensor cover: self-organization of sensor networks for efficient query execution

Abstract: Spatial query execution is an essential functionality of a sensor network, where a query gathers sensor data within a specific geographic region. Redundancy within a sensor network can be exploited to reduce the communication cost incurred in execution of such queries. Any reduction in communication cost would result in an efficient use of the battery energy, which is very limited in sensors. One approach to reduce the communication cost of a query is to self-organize the network, in response to a query, into a topology that involves only a small subset of the sensors sufficient to process the query. The query is then executed using only the sensors in the constructed topology.In this article, we design and analyze algorithms for such self-organization of a sensor network to reduce energy consumption. In particular, we develop the notion of a connected sensor cover and design a centralized approximation algorithm that constructs a topology involving a near-optimal connected sensor cover. We prove that the size of the constructed topology is within an log n factor of the optimal size, where n is the network size. We also develop a distributed self-organization version of our algorithm, and propose several optimizations to reduce the communication overhead of the algorithm. Finally, we evaluate the distributed algorithm using simulations and show that our approach results in significant communication cost reduction.

Tracking moving targets in a smart sensor network

Abstract: Networks of small, densely distributed wireless sensor nodes are capable of solving a variety of collaborative problems such as monitoring and surveillance We develop a simple algorithm that detects and tracks a moving target, and alerts sensor nodes along the projected path of the target The algorithm involves only simple computation and localizes communication only to the nodes in the vicinity of the target and its projected course The algorithm is evaluated on a small-scale testbed of Berkeley motes using a light source as the moving target The performance results are presented emphasizing the accuracy of the technique, along with a discussion about our experience in using such a platform for target tracking experiments

Poster abstract: serial data aggregation using space-filling curves in wireless sensor networks

Abstract: Many applications require that sensor observations in a given geographic region be aggregated or fused in a serial fashion This requires a routing path to be constructed through all sensors in that region This paper investigates efficient network traversal techniques to construct such path using the novel concept of space-filling curves