Proceedings Article•
Real-time tracking of transceiver-free objects for homeland security
01 Jan 2009-pp 1892-1895
TL;DR: This paper addresses the real-time localization of transceiver-free targets is addressed by means of learning by example methodology that exploits the received signal strength indicator available at the nodes of a wireless sensor network as input data.
Abstract: The increasing demand in homeland security speeds up the development of innovative and non-invasive systems to localize and track moving objects in complex environments. In this paper the real-time localization of transceiver-free targets is addressed by means of learning by example methodology that exploits the received signal strength indicator available at the nodes of a wireless sensor network as input data. This approach uses neither dedicated sensors nor active devices put on the target to localize both idle and moving objects. The definition of a customized classifier during an offline training procedure enables the real-time generation of a probability map of presence by processing the output of the support vector machine. Some selected experimental results validate the effectiveness of the proposed methodology applied in real scenarios.
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17 Oct 2011
TL;DR: In this article, a WSN-based system for the prevention of road incident because of wildlife road crossing is presented, composed by a network of sensors and actuators in order to detect wildlife approaching the road and to warn the driver in real-time by means of light signal devices.
Abstract: In this paper a preliminary study of applying a WSN-based system for the prevention of road incident because of wildlife road crossing is presented. The proposed system is composed by a network of sensors and actuators in order to detect wildlife approaching the road and to warn the driver in real-time by means of light signal devices. The nodes of the network are installed on the road sides and wirelessly interconnected in order to share the sensed data. A remote control unit deals with the storage and the processing of the collected information. Starting from the detection events, the proposed system identifies the areas with higher probability of wildlife crossing by means of customized classification approaches. The capabilities of the proposed system have been preliminarily assessed by means of an experimental setup installed in a controlled environment located in Alps regions strongly affected by the problem of wildlife-vehicle collisions.
28 citations
Cites background from "Real-time tracking of transceiver-f..."
...road and from one side to the other [8-15]....
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Proceedings Article•
11 Apr 2011TL;DR: In this paper, a learning-by-example strategy was proposed to estimate the unknown relation between the input data and the target position inside the monitored domain, and the real-time capabilities of the proposed approach have been experimentally verified when dealing with heterogeneous target movements in standard indoor areas.
Abstract: In this work, the exploitation of wireless systems for non-cooperative target localization and tracking is investigated. The information about wireless links quality is available on most of commercially available network devices and represents the input of the proposed methodology. A real-time probability of presence is generated by means of a learning by example strategy that estimates the unknown relation between the input data and the target position inside the monitored domain. The real-time capabilities of the proposed approach have been experimentally verified when dealing with heterogeneous target movements in standard indoor areas.
10 citations
TL;DR: In this paper idea of passive radar system based on popular wireless networks commonly named WIFI is presented and it is assumed, that all transmitters operate on the same band frequency and the passive radar receiver has to couple each transmission burst with transmitter position by decoding the physical address of transmitter from captured data stream.
Abstract: In this paper idea of passive radar system based on popular wireless networks commonly named WIFI is presented. In such an networks many transmitters operates in the same channel using multiple access. Wireless networks operating on frequencies 2.4GHz and 5GHz are very common today (IEEE 802.11 a/b/g/n). Classic passive radar determines bistatic distance and velocity by using cross-ambiguity function. To seek target position in XYZ space at least illumination of 3 different transmitters is required. In that paper it was assumed, that all transmitters operate on the same band frequency and the passive radar receiver has to couple each transmission burst with transmitter position by decoding the physical address of transmitter from captured data stream. Having most of the signal sources in our passive radar environment it is possible to detect and to localize objects of interest.
9 citations
Cites methods from "Real-time tracking of transceiver-f..."
...The indoor applications are also possible, but they should rely mostly on Doppler processing and power budget analysis and were presented by Viani, Olivieri, Massa [2]....
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Proceedings Article•
08 Apr 2013TL;DR: The experimental validation of a WSN-based smart system for the prevention of road incidents due to wildlife road crossing is presented and a selected set of results are reported to assess the capabilities and potentialities of the system.
Abstract: In this paper, the experimental validation of a WSN-based smart system for the prevention of road incidents due to wildlife road crossing is presented. The proposed wireless architecture integrates a multisensory hardware platform for the detection of movement patterns of wildlife along the monitored road sides. The adopted sensing technologies enable the extraction of heterogeneous movement features to be processed in real-time. The integration of data fusion strategies provides robust detection of warning events and the output triggers dedicated light signals when required. An experimental setup has been installed in real scenarios where the wildlife presence is detected. A selected set of results are reported to assess the capabilities and potentialities of the system.
6 citations
References
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TL;DR: Presenting a method for determining the necessary and sufficient conditions for consistency of learning process, the author covers function estimates from small data pools, applying these estimations to real-life problems, and much more.
Abstract: A comprehensive look at learning and generalization theory. The statistical theory of learning and generalization concerns the problem of choosing desired functions on the basis of empirical data. Highly applicable to a variety of computer science and robotics fields, this book offers lucid coverage of the theory as a whole. Presenting a method for determining the necessary and sufficient conditions for consistency of learning process, the author covers function estimates from small data pools, applying these estimations to real-life problems, and much more.
26,531 citations
"Real-time tracking of transceiver-f..." refers background in this paper
...Such a probability is derived from the unthresholded output of an ad-hoc SVM classifier ) (ω f [13], where...
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TL;DR: In this paper, the authors present two approaches for obtaining class probabilities, which can be reduced to linear systems and are easy to implement, and show conceptually and experimentally that the proposed approaches are more stable than the two existing popular methods: voting and the method by Hastie and Tibshirani (1998).
Abstract: Pairwise coupling is a popular multi-class classification method that combines all comparisons for each pair of classes. This paper presents two approaches for obtaining class probabilities. Both methods can be reduced to linear systems and are easy to implement. We show conceptually and experimentally that the proposed approaches are more stable than the two existing popular methods: voting and the method by Hastie and Tibshirani (1998)
1,888 citations
TL;DR: An overview of the technical aspects of the existing technologies for wireless indoor location systems is presented, providing a fundamental understanding of the issues related to indoor geolocation science that are needed for design and performance evaluation of emerging indoorGeolocation systems.
Abstract: This article presents an overview of the technical aspects of the existing technologies for wireless indoor location systems. The two major challenges for accurate location finding in indoor areas are the complexity of radio propagation and the ad hoc nature of the deployed infrastructure in these areas. Because of these difficulties a variety of signaling techniques, overall system architectures, and location finding algorithms are emerging for this application. This article provides a fundamental understanding of the issues related to indoor geolocation science that are needed for design and performance evaluation of emerging indoor geolocation systems.
954 citations
"Real-time tracking of transceiver-f..." refers background in this paper
...Starting from this assumption, the mobile target could be localized exploiting different parameters of its transmitted signal such as the direction of arrival (DOA) or the time of arrival (TOA) [4]....
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TL;DR: An algorithm is described that solves the sensor network localization problem using advanced optimization techniques and the effect of using very noisy measurements is studied and robust methods to deal with high noise are proposed.
Abstract: A sensor network localization problem is to determine the positions of the sensor nodes in a network given incomplete and inaccurate pairwise distance measurements. Such distance data may be acquired by a sensor node by communicating with its neighbors. We describe a general semidefinite programming (SDP)-based approach for solving the graph realization problem, of which the sensor network localization problems is a special case. We investigate the performance of this method on problems with noisy distance data. Error bounds are derived from the SDP formulation. The sources of estimation error in the SDP formulation are identified. The SDP solution usually has a rank higher than the underlying physical space which, when projected onto the lower dimensional space, generally results in high estimation error. We describe two improvements to ameliorate such a difficulty. First, we propose a regularization term in the objective function that can help to reduce the rank of the SDP solution. Second, we use the points estimated from the SDP solution as the initial iterate for a gradient-descent method to further refine the estimated points. A lower bound obtained from the optimal SDP objective value can be used to check the solution quality. Experimental results are presented to validate our methods and show that they outperform existing SDP methods. Note to Practitioners-Wireless sensor networks consist of a large number of inexpensive wireless sensors deployed in a geographical area with the ability to communicate with their neighbors within a limited radio range. Wireless sensor networks are finding increasing applicability to a range of monitoring applications in civil and military scenarios, such as biodiversity and geographical monitoring, smart homes, industrial control, surveillance, and traffic monitoring. It is often very useful in the applications of sensor networks to know the locations of the sensors. Global positioning systems suffer from many drawbacks in this scenario, such as high cost, line-of-sight issues, etc. Therefore, there is a need to develop robust and efficient algorithms that can estimate or "localize" sensor positions in a network by using only the mutual distance measures (received signal strength, time of arrival) that the wireless sensors receive from their neighbors. This paper describes an algorithm that solves the sensor network localization problem using advanced optimization techniques. We also study the effect of using very noisy measurements and propose robust methods to deal with high noise. Finally, simulation results for the algorithms are presented to demonstrate their performance in terms of computational effort and accuracy
474 citations
"Real-time tracking of transceiver-f..." refers background in this paper
...Nowadays, most of the proposed approaches deal with the localization of targets that wear an active transmitting and receiving device [1-3]....
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TL;DR: An in-depth study of two collaborative-localization methods, called the multidimensional scaling (MDS) and maximum-likelihood estimator (MLE), for wireless sensor networks, shows that MLE is more appropriate than MDS, given the underlying assumption of statistical signal models of the received-signal-strength-based localization problem.
Abstract: In this paper, we present an in-depth study of two collaborative-localization methods, called the multidimensional scaling (MDS) and maximum-likelihood estimator (MLE), for wireless sensor networks. From theoretical analysis, it is shown that MLE is more appropriate than MDS, given the underlying assumption of statistical signal models of the received-signal-strength-based localization problem. We also show that MDS can approximately achieve asymptotic efficiency with appropriate weighting schemes in some scenarios. From extensive simulation results, it is noted that the nonlinear least square algorithms that are commonly used to determine MLE are not as efficient as the iterative MDS algorithms. Thus, we propose a new integrated method MDS-MLE to effectively benefit from the strength of both methods. In the new method, MDS is used as an initialization method for MLE. With the solution of MDS as an initial value, MLE converges much faster and achieves significantly better performance than with random initial values. Superior performance of the new method is clearly demonstrated through simulation results. The effects of the deployment density of sensor nodes and reference nodes (RNs), as well as the deployment structure of RNs, are also studied through various simulations.
208 citations
"Real-time tracking of transceiver-f..." refers background in this paper
...In such approaches, the localization problem is based on the known location coordinates of some reference nodes and on the RSS measurements among the other network elements....
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...The output of the filtering procedure can be seen as a stabilized value ( )( ))(kjlklk tRSSIRSSI Ω= obtained after J time samples....
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...;( lkϕ being the l kRSSI measurements in presence and absence of the moving target, respectively....
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...Other location-sensing modalities based on received signal strength (RSS) have been studied to localize active targets exploiting the easily measurable RSS [5]....
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...The quality of each link can be quantified by the Received Signal Strength Indicator ( RSSI ) as an easily measurable parameter....
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