this paper presents a framework for power-efficient detection in embeddedsensorsystems. State detection is structured as a decision tree classifier that dynamically orders the activation and adjusts the sampling rat...
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ISBN:
(纸本)9781595937636
this paper presents a framework for power-efficient detection in embeddedsensorsystems. State detection is structured as a decision tree classifier that dynamically orders the activation and adjusts the sampling rate of the sensors (termed groggy wakeup), such that only the data necessary to determine the system state is collected at any given time. this classifier can be tuned to trade-off accuracy and power in a structured, parameterized fashion. An embedded instantiation of these classifiers, including real-time sensor control, is described. An application based on a wearable gait monitor provides quantitative support for this framework. the decision tree classifiers achieved roughly identical detection accuracies to those obtained using support vector machines while drawing three times less power. Both simulation and real-time operation of the classifiers demonstrate that our multi-tiered classifier determines states as accurately as a single-trigger (binary) wakeup system while drawing as little as half as much power and with only a negligible increase in latency.
Progress in low power miniaturized electronics and wireless technologies have enabled many innovative applications. Of particular interest is the Internet of things (IoT) that has dominated the world of ICT in the las...
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ISBN:
(纸本)9781450354592
Progress in low power miniaturized electronics and wireless technologies have enabled many innovative applications. Of particular interest is the Internet of things (IoT) that has dominated the world of ICT in the last half a decade enabling many smart systems and applications. At the same time, we also see much enthusiasm with respect to space missions and applications including terrestrial applications, apart from exploring the universe. We believe that innovations in the domain of IoT will significantly influence the space related activities - both research and development. In this article, we chart out the innovations in space and the vision with respect to embedded and wireless systems for space applications. In particular, we bring in the notion of sensor Wireless Actuator Networks in Space (SWANS) and Space Pixels to explain IoT in space. We explain with examples what we envision for the next decade and also the challenges therein. We briefly put forth our four major targets in the next five years.
Existing protocols for Secure key establishment all rely on an unspecified mechanism for initially deploying secrets to sensor nodes. However, no commercially viable and secure mechanism exists for initial setup. With...
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ISBN:
(纸本)9781595937636
Existing protocols for Secure key establishment all rely on an unspecified mechanism for initially deploying secrets to sensor nodes. However, no commercially viable and secure mechanism exists for initial setup. Without a guarantee of secure key deployment, the traffic over a sensor network cannot be presumed secure. To address this problem, we present a user-friendly protocol for the secure deployment of cryptographic keys in sensor networks. We propose it collection of five techniques to prevent an attacker from eavesdropping on key deployment. To demonstrate feasibility for real-world use, we implement our protocol on Telos motes and conduct a user study.
Modern microcontrollers come with a selection of clock sources that have widely differing frequencies and power consumptions. For applications whose workloads vary over time, dynamically changing the clock can provide...
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ISBN:
(纸本)9781450359528
Modern microcontrollers come with a selection of clock sources that have widely differing frequencies and power consumptions. For applications whose workloads vary over time, dynamically changing the clock can provide significant energy savings. the varying constraints of embedded hardware environments and the complex interactions of multiprogrammed systems makes this approach burdensome to do in application logic. Power Clocks orchestrates energy optimizing clock management in the kernel, obviating the need for application involvement while still achieving acceptable performance for typical workloads. this poster describes Power Clocks's design and presents preliminary results.
We present a method to extract topology information from detection events of mobile entities moving through a network of binary sensors. We extract the topological structure of possible paths in the network by analyzi...
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ISBN:
(纸本)9781605587486
We present a method to extract topology information from detection events of mobile entities moving through a network of binary sensors. We extract the topological structure of possible paths in the network by analyzing the time correlation of events at different sensors. the histograms of time delays between any two sensors contain the necessary information to reconstruct the network topology. this data is heavily corrupted by noise due to multiple agents in the network. We therefore use a mixture model of multiple Gaussian and a uniform distribution to explicitly isolate the noise. Our algorithm yields a graph representing the topology of our sensor network along with average travel time between nodes.
We address the problem of analysing performance anomalies in sensor networks. In this paper, we propose an approach that uses the local flash storage of the motes for logging system data, in combination with online st...
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ISBN:
(纸本)9781450302654
We address the problem of analysing performance anomalies in sensor networks. In this paper, we propose an approach that uses the local flash storage of the motes for logging system data, in combination with online statistical analysis. Our results show not only that this is a feasible method but that the overhead is significantly lower than that of communication-centric methods, and that interesting patterns can be revealed when calculating the correlation of large data sets of separate event types.
Battery-free sensor nodes rely solely on energy harvested from the environment and thus employ supercapacitors as energy storage to allow perpetual operation in absence of ambient energy. To guarantee that the sensor ...
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ISBN:
(纸本)9781450398862
Battery-free sensor nodes rely solely on energy harvested from the environment and thus employ supercapacitors as energy storage to allow perpetual operation in absence of ambient energy. To guarantee that the sensor nodes can survive in periods where no harvested energy is available, it is crucial to accurately estimate the lifetime of these devices. However, as we show experimentally in this paper, an accurate lifetime estimation is non-trivial due to the supercapacitors' complex discharge characteristics (e.g., leakage currents) and large capacitance tolerances. After showing that empirical data capturing the supercapacitors' characteristics is essential towards an accurate estimation of the system's lifetime, we introduce an enhanced leakage model that is computationally lightweight and evaluate its accuracy experimentally.
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