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Wireless sensor networks consist of collections of small, low-power nodes that interface or interact with the physical environment. The ability to add new func-tionality or perform software maintenance without having to physically reach each individual node is already an essential service, even at the limited scale at which current sensor networks are(More)
TCP congestion avoidance mechanisms are based on adjustments to the congestion-window size, triggered by the ACK clock. These mechanisms are not well matched to large but intermittent bursts of traffic, such as responses from a HTTP/1.1-based web server. Idle periods between bursts (web page replies) stop the ACK clock and hence disrupt even data flow. When(More)
In wireless ad hoc networks and sensor networks, energy use is in many cases the most important constraint since it corresponds directly to operational lifetime. This paper presents two topology control protocols that extend the lifetime of dense ad hoc networks while preserving con-nectivity, the ability for nodes to reach each other. Our protocols(More)
Experience with wired networks has provides guidance about what level of detail is appropriate for simulation-based protocol studies. Wireless simulations raise many new questions about approriate levels of detail in simulation models for radio propagation and energy consumption. This paper describes the trade-offs associated with adding detail to(More)
greatly extend our ability to monitor and control the physical world. The availability of microsensors and low-power wireless communications enables the deployment of densely distributed sensor/actuator networks for a wide range of biological and environmental monitoring applications, from marine to soil and atmospheric contexts. Networked sensors can(More)
This technical report captures the web page http://netweb.usc.edu/ ~rsinha/pkt-sizes/, summarizing our observations about packet sizes on the Internet in October 2005. Other than reformatting, the technical content has not been changed. We were recently looking at packet size distributions in Internet traffic. We observed two surprising things. First,(More)
This report summarizes our research directions in underwater sensor networks. We highlight potential applications to offshore oilfields for seismic monitoring, equipment monitoring, and underwater robotics. We identify research directions in short-range acoustic communications, MAC, time synchronization, and localization protocols for high-latency acoustic(More)
We undertake a systematic experimental study of the effects of concurrent packet transmissions in low-power wireless networks. Our measurements, conducted with Mica2 motes equipped with CC1000 radios, confirm that guaranteeing successful packet reception with high probability in the presence of concurrent transmissions requires that the(More)
Over the last decade, embedded sensing systems have been successfully deployed in a range of application areas, from education and science to military and industry. These systems are becoming more robust, capable, and widely adopted. Yet today, most sensor networks function in isolated patches, each with different mechanisms to deliver data to their users,(More)