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Van Ha Tang, Abdesselam Bouzerdoum, Son Lam Phung
Compressed sensing techniques have been applied to through-the-wall radar imaging (TWRI) and multipolarization TWRI for fast data acquisition and enhanced target localization. The studies so far in this area have either assumed effective wall clutter removal prior to image formation or performed signal estimation, wall clutter mitigation, and image formation independently. This paper proposes a low-rank and sparse imaging model for jointly addressing the problem of wall clutter mitigation and image formation in multichannel TWRI...
April 2018: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
Qi Yang, Bin Deng, Hongqiang Wang, Yuliang Qin, Ye Zhang
Motion compensation is a crucial step to inverse synthetic aperture radar imaging, and envelope correction is the foundation of motion compensation. Research on envelope correction based on the small-angle imaging model has matured after years of development. However, the small-angle imaging model is not applicable to parameter estimation and imaging of micro-motion targets. According to the characteristics of the micro-motion targets and the superiorities of terahertz imaging radar, an envelope correction method for micro-motion targets in the terahertz region was proposed in this paper, including the jump error correction based on periodic correction and drift error compensation based on nonlinear fitting...
January 15, 2018: Sensors
Xiaolong Su, Zhen Liu, Xin Chen, Xizhang Wei
Due to its widespread application in communications, radar, etc., the orthogonal frequency division multiplexing (OFDM) signal has become increasingly urgent in the field of localization. Under uniform circular array (UCA) and near-field conditions, this paper presents a closed-form algorithm based on phase difference for estimating the three-dimensional (3-D) location (azimuth angle, elevation angle, and range) of the OFDM signal. In the algorithm, considering that it is difficult to distinguish the frequency of the OFDM signal's subcarriers and the phase-based method is always affected by errors of the frequency estimation, this paper employs sparse representation (SR) to obtain the super-resolution frequencies and the corresponding phases of subcarriers...
January 14, 2018: Sensors
Jean-Michel Friedt, Gilles Martin, Gwenhael Goavec-Mérou, David Rabus, Sébastien Alzuaga, Lilia Arapan, Marianne Sagnard, Émile Carry
Passive wireless transducers are used as sensors, probed by a RADAR system. A simple way to separate the returning signal from the clutter is to delay the response, so that the clutter decays before the echoes are received. This can be achieved by introducing a fixed delay in the sensor design. Acoustic wave transducers are ideally suited as cooperative targets for passive, wireless sensing. The incoming electromagnetic pulse is converted into an acoustic wave, propagated on the sensor substrate surface, and reflected as an electromagnetic echo...
January 16, 2018: Sensors
Andrea Di Pasquale, Giovanni Nico, Alfredo Pitullo, Giuseppina Prezioso
The aim of this paper is to describe how ground-based radar interferometry can provide displacement measurements of earth dam surfaces and of vibration frequencies of its main concrete infrastructures. In many cases, dams were built many decades ago and, at that time, were not equipped with in situ sensors embedded in the structure when they were built. Earth dams have scattering properties similar to landslides for which the Ground-Based Synthetic Aperture Radar (GBSAR) technique has been so far extensively applied to study ground displacements...
January 16, 2018: Sensors
Andreas Gregoriades, Alistair Sutcliffe
Situation awareness (SA) constitutes a critical factor in road safety, strongly related to accidents. This paper describes the evaluation of a proposed SA enhancement system (SAES) that exploits augmented reality through a head-up display. Two SAES designs were evaluation (information rich v. minimal information) using a custom-made simulator and the Situation Awareness Global Assessment Technique (SAGAT) with performance and EEG measures. The paper describes the process of assessing the SA of drivers using the SAES, through a series of experiments with participants in a Cave Automatic Virtual Environment (CAVE)...
January 11, 2018: Ergonomics
Gregory Phillips, Amy K Johnson, Christian N Adames, Brian Mustanski
Serogroup C invasive meningococcal disease (IMD) outbreaks in men who have sex with men (MSM) have been occurring with greater frequency in urban areas across the United States. An effective vaccine for IMD is available and is recommended for MSM in outbreak settings. Particular subgroups of MSM have been disproportionately represented in outbreaks, specifically young, Black, and HIV-positive MSM. As little is known about the knowledge, awareness, and vaccination status of young MSM, we sought to describe this and explore racial/ethnic differences...
January 1, 2018: Health Education & Behavior: the Official Publication of the Society for Public Health Education
Jiahua Zhu, Xuezhi Wang, Xiaotao Huang, Sofia Suvorova, Bill Moran
Golay complementary waveforms can, in theory, yield radar returns of high range resolution with essentially zero sidelobes. In practice, when deployed conventionally, while high signal-to-noise ratios can be achieved for static target detection, significant range sidelobes are generated by target returns of nonzero Doppler causing unreliable detection. We consider signal processing techniques using Golay complementary waveforms to improve radar detection performance in scenarios involving multiple nonzero Doppler targets...
January 11, 2018: Sensors
Thtreswar Beeharry, Riad Yahiaoui, Kamardine Selemani, Habiba Hafdallah Ouslimani
A thin broadband dual-layer radar absorber based on periodic Frequency Selective Surfaces (FSS) to tackle Electromagnetic Interference (EMI) in radomes is presented in this article. The proposed structure consists of periodically arranged metallic patterns printed on two dielectric substrates separated by an optimized air gap. Under normal incidence, the proposed structure exhibits at least 89.7% of absorption in the whole band of 4.8 GHz to 11.1 GHz for both Transverse Electric (TE) and Magnetic (TM) polarizations...
January 10, 2018: Scientific Reports
Feixiang Zhao, Yongxiang Liu, Kai Huo, Shuanghui Zhang, Zhongshuai Zhang
A novel radar high-resolution range profile (HRRP) target recognition method based on a stacked autoencoder (SAE) and extreme learning machine (ELM) is presented in this paper. As a key component of deep structure, the SAE does not only learn features by making use of data, it also obtains feature expressions at different levels of data. However, with the deep structure, it is hard to achieve good generalization performance with a fast learning speed. ELM, as a new learning algorithm for single hidden layer feedforward neural networks (SLFNs), has attracted great interest from various fields for its fast learning speed and good generalization performance...
January 10, 2018: Sensors
Pablo Gil, Beatriz Alacid
This work presents a method for oil-spill detection on Spanish coasts using aerial Side-Looking Airborne Radar (SLAR) images, which are captured using a Terma sensor. The proposed method uses grayscale image processing techniques to identify the dark spots that represent oil slicks on the sea. The approach is based on two steps. First, the noise regions caused by aircraft movements are detected and labeled in order to avoid the detection of false-positives. Second, a segmentation process guided by a map saliency technique is used to detect image regions that represent oil slicks...
January 8, 2018: Sensors
Pauline Baas, Tom van der Valk, Linda Vigilant, Urbain Ngobobo, Escobar Binyinyi, Radar Nishuli, Damien Caillaud, Katerina Guschanski
OBJECTIVES: The critically endangered Grauer's gorilla (Gorilla beringei graueri) has experienced an estimated 77% population decline within a single generation. Although crucial for informed conservation decisions, there is no clear understanding about population structure and distribution of genetic diversity across the species' highly fragmented range. We fill this gap by studying several core and peripheral Grauer's gorilla populations throughout their distribution range. MATERIALS AND METHODS: We generated genetic profiles for a sampling of an unstudied population of Grauer's gorillas from within the species' core range at 13 autosomal microsatellite loci and combined them with previously published and newly generated data from four other Grauer's gorilla populations, two mountain gorilla populations, and one western lowland gorilla population...
January 4, 2018: American Journal of Physical Anthropology
Thao T Nguyen, Michael R Souryal, Anirudha Sahoo, Timothy A Hall
Spectrum sharing in the 3.5 GHz band between commercial and government users along U.S. coastal areas depends on an environmental sensing capability (ESC)-that is, a network of radio frequency sensors and a decision system-to detect the presence of incumbent shipborne radar systems and trigger protective measures, as needed. It is well known that the sensitivity of these sensors depends on the aggregate interference generated by commercial systems to the incumbent radar receivers, but to date no comprehensive study has been made of the aggregate interference in realistic scenarios and its impact on the requirement for detection of the radar signal...
September 2017: IEEE Trans Cogn Commun Netw
Matt R Cross, Pierre Samozino, Scott R Brown, Jean-Benoît Morin
PURPOSE: We sought to compare force-velocity relationships developed from unloaded sprinting acceleration to that compiled from multiple sled-resisted sprints. METHODS: Twenty-seven mixed-code athletes performed six to seven maximal sprints, unloaded and towing a sled (20-120% of body-mass), while measured using a sports radar. Two methods were used to draw force-velocity relationships for each athlete: A multiple trial method compiling kinetic data using pre-determined friction coefficients and aerodynamic drag at maximum velocity from each sprint; and a validated single trial method plotting external force due to acceleration and aerodynamic drag and velocity throughout an acceleration phase of an unloaded sprint (only)...
January 4, 2018: European Journal of Applied Physiology
Merv Fingas, Carl E Brown
The technical aspects of oil spill remote sensing are examined and the practical uses and drawbacks of each technology are given with a focus on unfolding technology. The use of visible techniques is ubiquitous, but limited to certain observational conditions and simple applications. Infrared cameras offer some potential as oil spill sensors but have several limitations. Both techniques, although limited in capability, are widely used because of their increasing economy. The laser fluorosensor uniquely detects oil on substrates that include shoreline, water, soil, plants, ice, and snow...
December 30, 2017: Sensors
Lawren L Gamble, Daniel J Inman
Motivated by the lack of research in tailless morphing aircraft in addition to the current inability to measure the resultant aerodynamic forces and moments of bird control maneuvers, this work aims to develop and test a multi-functional morphing control surface based on the horizontal tail of birds for a low-radar-signature UAV. Customized Macro Fiber Composite (MFC) actuators were designed to achieve yaw control across a range of sideslip angles by inducing three dimensional curvature as a result of bending-twisting coupling, a well-known phenomenon in classical fiber composite theory...
January 4, 2018: Bioinspiration & Biomimetics
Eric C Makhni, Vincent A Lizzio, Fabien Meta, Jeffrey P Stephens, Kelechi R Okoroha, Vasilios Moutzouros
PURPOSE: To assess the precision of a new wearable device in detecting medial elbow torque during the pitching motion in competitive baseball pitchers and to determine the differences in torque across pitch types and thrower demographic characteristics. METHODS: High school and collegiate baseball pitchers were recruited from August 1, 2016, to January 31, 2017, through direct request by athletic trainers and coaches. Body dimensions and throwing arm measurements of the participants were collected...
December 27, 2017: Arthroscopy: the Journal of Arthroscopic & related Surgery
Marappan Jayanthi, Selvasekar Thirumurthy, Muthusamy Samynathan, Muthusamy Duraisamy, Moturi Muralidhar, Jangam Ashokkumar, Koyadan Kizhakkedath Vijayan
Climate change impact on the environment makes the coastal areas vulnerable and demands the evaluation of such susceptibility. Historical changes in the shoreline positions and inundation based on projected sea-level scenarios of 0.5 and 1 m were assessed for Nagapattinam District, a low-lying coastal area in the southeast coast of India, using high-resolution Shuttle Radar Topography Mission data; multi-dated Landsat satellite images of 1978, 1991, 2003, and 2015; and census data of 2011. Image processing, geographical information system, and digital shoreline analysis system methods were used in the study...
December 28, 2017: Environmental Monitoring and Assessment
Pasquale Imperatore, Antonio Iodice, Daniele Riccio
A general, approximate perturbation method, able to provide closed-form expressions of scattering from a layered structure with an arbitrary number of rough interfaces, has been recently developed. Such a method provides a unique tool for the characterization of radar response patterns of natural rough multilayers. In order to show that, here, for the first time in a journal paper, we describe the application of the developed perturbation theory to fractal interfaces; we then employ the perturbative method solution to analyze the scattering from real-world layered structures of practical interest in remote sensing applications...
December 27, 2017: Sensors
Zhibin Yu, Duo Zhao, Zhiqiang Zhang
Due to the non-contact nature, using Doppler radar sensors to detect vital signs such as heart and respiration rates of a human subject is getting more and more attention. However, the related detection-method research meets lots of challenges due to electromagnetic interferences, clutter and random motion interferences. In this paper, a novel third-order cyclic cummulant (TOCC) detection method, which is insensitive to Gaussian interference and non-cyclic signals, is proposed to investigate the heart and respiration rate based on continuous wave Doppler radars...
December 26, 2017: Sensors
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