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Motivated by the needs of precise forest inventory and real-time surveillance for ecosystem management, in this paper we present GreenOrbs [2], a wireless sensor network system and its application for canopy closure estimates. Both the hardware and software designs of GreenOrbs are tailored for sensing in wild environments without human supervision,(More)
Constructive interference-based flooding (CIBF) is a latency-optimal flooding protocol, which can realize millisecond network flooding latency and submicrosecond time synchronization accuracy, require no network state information, and be adapted to topology changes. However, constructive interference (CI) has a precondition to function, i.e., the maximum(More)
—Most P2P Video-on-Demand (VOD) schemes focus more on mending service architectures and optimizing overlays but do not carefully consider the user behavior and the benefit of prefetching strategies. As a result, they cannot better support VCR-oriented services in terms of substantive asynchronous clients or free VCR controls for P2P VODs. To address this(More)
—Motivated by the needs of precise carbon emission measurement and real-time surveillance for CO2 management in cities, we present CitySee, a real-time CO2-monitoring system using sensor networks for an urban area (around 100 square kilometers). In order to conduct environment monitoring in a real-time and long-term manner, CitySee has to address the(More)
Existing localization approaches are divided into two groups: range-based and range-free. The range-free schemes often suffer from poor accuracy and low scalabil-ity, while the range-based localization approaches heavily depend on extra hardware capabilities or rely on the absolute RSSI (received signal strength indicator) values, far from practical. In(More)
Demands on better interacting with physical world require an effective and comprehensive collaboration mechanism among multiple heterogeneous sensor networks. Previous works mainly focus on improving each single and specific sensor network, thus fail to address this newly emerged issue. In this paper, we study the issue of collaborative query processing(More)
Understanding the packet delivery performance of a wireless sensor network (WSN) is critical for improving system performance and exploring future developments and applications of WSN techniques. In spite of many empirical measurements in the literature, we still lack in-depth understanding on how and to what extent different factors contribute to the(More)
—Demands on better interacting with physical world require an effective and efficient collaboration mechanism of multiple heterogeneous sensor networks. Previous works mainly focus on each single and specific sensor network, thus failing to address issues in the newly emerging scenario. In this paper, we propose COSE, a query-centric framework of(More)
—In wireless sensor networks (WSNs), diagnosis is a crucial and challenging task due to the distributed nature and stringent resources. Most previous approaches are supervised, relying on a-priori knowledge of network faults. Our experience with GreenOrbs, a long-term large-scale WSN system, reveals the need of diagnosis in an agnostic manner. Specifically,(More)