| 1. |
- Bader, Sebastian, et al.
(author)
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Adaptive synchronization for duty-cycling in environmental wireless sensor networks
- 2009
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In: ISSNIP 2009 - Proceedings of 2009 5th International Conference on Intelligent Sensors, Sensor Networks and Information Processing. - : IEEE conference proceedings. - 9781424435173 ; , s. 49-54
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Conference paper (peer-reviewed)abstract
- In wireless sensor networks, as energy limited systems, communication is a costly activity. For this reason duty cycling approaches are commonly used, because they can limit the overall power consumption of a sensor node tremendously by shutting down communication sub-circuits whenever they are not used. However, for efficient power reduction nodes have to know the exact times when they are supposed to communicate in the network. Synchronization can be used to accomplish this and comes with additional features such as the possibility of cooperative sampling at a given time. In this paper we propose a synchronization protocol that introduces low overhead due to broadcast master-node synchronization, while still accomplishing synchronization accuracies in the order of 100 μs. The protocol is intended for periodic data collection applications that are common tasks in environmental monitoring systems. Since changes in environmental conditions can have a large effect on the synchronization behavior, we further present a temperature compensation algorithm for the proposed synchronization protocol that allows stable usage of synchronization in a wide range of temperatures. Measurement results are taken from implementing the protocol on sensor node platforms and show the real world performance of the presented methods.
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| 2. |
- Basiri, Meysam, et al.
(author)
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Distributed Control of Triangular Sensor Formations with Angle-Only Constraints
- 2009
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In: 2009 INTERNATIONAL CONFERENCE ON INTELLIGENT SENSORS, SENSOR NETWORKS AND INFORMATION PROCESSING (ISSNIP 2009). - NEW YORK : IEEE. - 9781424435173 ; , s. 121-126
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Conference paper (peer-reviewed)abstract
- This paper considers the coupled formation control of three mobile agents moving in the plane. Each agent has only local inter-agent bearing knowledge and is required to maintain a specified angular separation relative to its neighbors. The problem considered in this paper differs from similar problems in the literature since no inter-agent distance measurements are employed and the desired formation is specified entirely by the internal triangle angles. Each agent's control law is distributed and based only on its locally measured bearings. A convergence result is established which guarantees global convergence of the formation to the desired formation shape.
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| 3. |
- Bishop, Adrian N., et al.
(author)
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An Optimality Analysis of Sensor-Target Geometries for Signal Strength Based Localization
- 2009
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In: 2009 INTERNATIONAL CONFERENCE ON INTELLIGENT SENSORS, SENSOR NETWORKS AND INFORMATION PROCESSING (ISSNIP 2009). - NEW YORK : IEEE. - 9781424435173 ; , s. 127-132
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Conference paper (peer-reviewed)abstract
- In this paper we characterize the bounds on localization accuracy in signal strength based localization. In particular, we provide a novel and rigorous analysis of the relative receiver-transmitter geometry and the effect of this geometry on the potential localization performance. We show that uniformly spacing sensors around the target is not optimal if the sensor-target ranges are not identical and is not necessary in any case. Indeed, we show that in general the optimal sensor-target geometry for signal strength based localization is not unique.
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| 4. |
- Boberg, Anders, et al.
(author)
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Robocentric Mapping and Localization in Modified Spherical Coordinates with Bearing Measurements
- 2009
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In: 2009 INTERNATIONAL CONFERENCE ON INTELLIGENT SENSORS, SENSOR NETWORKS AND INFORMATION PROCESSING (ISSNIP 2009). - NEW YORK : IEEE. - 9781424435173 ; , s. 139-144
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Conference paper (peer-reviewed)abstract
- In this paper, a new approach to robotic mapping is presented that uses modified spherical coordinates in a robot-centered reference frame and a bearing-only measurement model. The algorithm provided in this paper permits robust delay-free state initialization and is computationally more efficient than the current standard in bearing-only (delay-free initialized) simultaneous localization and mapping (SLAM). Importantly, we provide a detailed nonlinear observability analysis which shows the system is generally observable. We also analyze the error convergence of the filter using stochastic stability analysis. We provide an explicit bound on the asymptotic mean state estimation error. A comparison of the performance of this filter is also made against a standard world-centric SLAM algorithm in a simulated environment.
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| 5. |
- Rahmathullah, Abu Sajana, 1986, et al.
(author)
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A low-complexity algorithm for intrusion detection in a PIR-based Wireless Sensor Network
- 2009
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In: Intelligent Sensors, Sensor Networks and Information Processing (ISSNIP), 2009, Melbourne, Australia. - 9781424435173 ; , s. 337 - 342
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Conference paper (peer-reviewed)abstract
- We present a low-complexity algorithm for intrusion detection in the presence of clutter arising from wind-blown vegetation, using passive infra-red (PIR) sensors in a wireless sensor network (WSN). The algorithm is based on a combination of Haar transform (HT) and support-vector-machine (SVM) based training and was field tested in a network setting comprising of 15-20 sensing nodes. Also contained in this paper is a closed-form expression for the signal generated by an intruder moving at a constant velocity. It is shown how this expression can be exploited to determine the direction of motion information and the velocity of the intruder from the signals of three well-positioned sensors.
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