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In old times, castles were surrounded by moats (deep trenches filled with water, and even alligators) to thwart or discourage intrusion attempts. One can now replace such barriers with stealthy and wireless sensors. In this paper, we develop theoretical foundations for laying barriers of wireless sensors. We define the notion of <i>k</i>-barrier coverage of(More)
We give a formal de nition of what it means for a system to \tolerate" a class of \faults". The de nition consists of two conditions: One, if a fault occurs when the system state is within a set of \legal" states, the resulting state is within some larger set and, if faults continue occurring, the system state remains within that larger set (Closure). And(More)
Intrusion detection is a surveillance problem of practical import that is well suited to wireless sensor networks. In this paper, we study the application of sensor networks to the intrusion detection problem and the related problems of classifying and tracking targets. Our approach is based on a dense, distributed, wireless network of multi-modal(More)
We present the design of the eXtreme Scale Mote, a new sensor network platform for reliably detecting and classifying, and quickly reporting, rare, random, and ephemeral events in a large-scale, long-lived, and retaskable manner. This new mote was designed for the ExScal project which seeks to demonstrate a 10,000 node network capable of discriminating(More)
We address the challenges of bursty convergecast in multi-hop wireless sensor networks, where a large burst of packets from different locations needs to be transported reliably and in real-time to a base station. Via experiments on a 49 MICA2 mote sensor network using a realistic traffic trace, we determine the primary issues in bursty convergecast, and(More)
Multicast/broadcast is an important service primitive in networks. The IEEE 802.11 multicast/broadcast protocol is based on the basic access procedure of Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA). This protocol does not provide any media access control (MAC) layer recovery on multicast/broadcast frames. As a result, the reliability of(More)
The <i>Kansei</i> testbed at The Ohio State University is designed to facilitate research on networked sensing applications at scale. <i>Kansei</i> embodies a unique combination of characteristics as a result of its design focus on sensing and scaling: (i) Heterogeneous hardware infrastructure with dedicated node resources for local computation, storage,(More)