WorldWideScience

Sample records for ground clutter processing

  1. Mine detection using SF-GPR: A signal processing approach for resolution enhancement and clutter reduction

    DEFF Research Database (Denmark)

    Karlsen, Brian; Jakobsen, Kaj Bjarne; Larsen, Jan;

    2001-01-01

    Proper clutter reduction is essential for Ground Penetrating Radar data since low signal-to-clutter ratio prevent correct detection of mine objects. A signal processing approach for resolution enhancement and clutter reduction used on Stepped-Frequency Ground Penetrating Radar (SF-GPR) data is pr...

  2. Ground clutter cancellation in incoherent radars: solutions for EISCAT Svalbard radar

    Directory of Open Access Journals (Sweden)

    T. Turunen

    Full Text Available Incoherent scatter radars measure ionosphere parameters using modified Thomson scatter from free electrons in the target (see e.g. Hagfors, 1997. The integrated cross section of the ionospheric scatterers is extremely small and the measurements can easily be disturbed by signals returned by unwanted targets. Ground clutter signals, entering via the antenna side lobes, can render measurements at the nearest target ranges totally impossible. The EISCAT Svalbard Radar (ESR, which started measurements in 1996, suffers from severe ground clutter and the ionosphere cannot be measured in any simple manner at ranges less than about 120–150 km, depending on the modulation employed. If the target and clutter signals have different, and clearly identifiable, properties then, in principle, there are always ways to eliminate the clutter. In incoherent scatter measurements, differences in the coherence times of the wanted and unwanted signals can be used for clutter cancellation. The clutter cancellation must be applied to all modulations, usually alternating codes in modern experiments, used for shorter ranges. Excellent results have been obtained at the ESR using a simple pulse-to-pulse clutter subtraction method, but there are also other possibilities.

    Key words: Radio science (ionospheric physics; signal processing; instruments and techniques

  3. Analysis of Geosynchronous Satellite-air Bistatic SAR Clutter Characteristics from the Point of View of Ground Moving Target Indication

    Directory of Open Access Journals (Sweden)

    Zhang Dan-dan

    2013-09-01

    Full Text Available Under the geometry of geosynchronous satellite-air bistatic SAR where the geosynchronous satellite is the transmitter and aerostat is the receiver, in order to suppress clutter and detect slowly moving target using Space Time Adaptive Processing (STAP, it is necessary to analyze the clutter characteristics. From the point of view of ground moving target indication, the theory model of the clutter characteristics under the geometry of geosynchronous satellite-space bistatic SAR is analyzed and established in this paper; especially, the range-dependence characteristics of the angle-Doppler curve of the clutter is analyzed. Finally, the simulation verifies correctness of the analysis. The theory model and the conclusion in this paper indicates the clutter characteristics of the new geosynchronous satellite-air bistatic SAR mode, and provide theory basis for the selection and research of ground moving target indication method under this mode.

  4. Arta process model of maritime clutter and targets

    CSIR Research Space (South Africa)

    McDonald

    2012-10-01

    Full Text Available A coherent autoregressive–to–anything (ARTA) stationary stochastic process for modelling maritime clutter and targets is presented in this paper. The ARTA stochastic process model is an improvement over previous models in the sense...

  5. Ground clutter cancellation in incoherent radars: solutions for EISCAT Svalbard radar

    Science.gov (United States)

    Turunen, T.; Markkanen, J.; van Eyken, A. P.

    2000-09-01

    Incoherent scatter radars measure ionosphere parameters using modified Thomson scatter from free electrons in the target (see e.g. Hagfors, 1997). The integrated cross section of the ionospheric scatterers is extremely small and the measurements can easily be disturbed by signals returned by unwanted targets. Ground clutter signals, entering via the antenna side lobes, can render measurements at the nearest target ranges totally impossible. The EISCAT Svalbard Radar (ESR), which started measurements in 1996, suffers from severe ground clutter and the ionosphere cannot be measured in any simple manner at ranges less than about 120-150 km, depending on the modulation employed. If the target and clutter signals have different, and clearly identifiable, properties then, in principle, there are always ways to eliminate the clutter. In incoherent scatter measurements, differences in the coherence times of the wanted and unwanted signals can be used for clutter cancellation. The clutter cancellation must be applied to all modulations, usually alternating codes in modern experiments, used for shorter ranges. Excellent results have been obtained at the ESR using a simple pulse-to-pulse clutter subtraction method, but there are also other possibilities.

  6. Ground-Vegetation Clutter Affects Phyllostomid Bat Assemblage Structure in Lowland Amazonian Forest.

    Science.gov (United States)

    Marciente, Rodrigo; Bobrowiec, Paulo Estefano D; Magnusson, William E

    2015-01-01

    Vegetation clutter is a limiting factor for bats that forage near ground level, and may determine the distribution of species and guilds. However, many studies that evaluated the effects of vegetation clutter on bats have used qualitative descriptions rather than direct measurements of vegetation density. Moreover, few studies have evaluated the effect of vegetation clutter on a regional scale. Here, we evaluate the influence of the physical obstruction of vegetation on phyllostomid-bat assemblages along a 520 km transect in continuous Amazonian forest. We sampled bats using mist nets in eight localities during 80 nights (3840 net-hours) and estimated the ground-vegetation density with digital photographs. The total number of species, number of animalivorous species, total number of frugivorous species, number of understory frugivorous species, and abundance of canopy frugivorous bats were negatively associated with vegetation clutter. The bat assemblages showed a nested structure in relation to degree of clutter, with animalivorous and understory frugivorous bats distributed throughout the vegetation-clutter gradient, while canopy frugivores were restricted to sites with more open vegetation. The species distribution along the gradient of vegetation clutter was not closely associated with wing morphology, but aspect ratio and wing load differed between frugivores and animalivores. Vegetation structure plays an important role in structuring assemblages of the bats at the regional scale by increasing beta diversity between sites. Differences in foraging strategy and diet of the guilds seem to have contributed more to the spatial distribution of bats than the wing characteristics of the species alone.

  7. Ground Clutter Reduction from GPR Data for Identification of Shallowly Buried Landmines

    Science.gov (United States)

    Nishimoto, Masahiko; Jandieri, Vakhtang

    A method for reducing ground clutter contribution from ground penetrating radar (GPR) data is proposed for discrimination of landmines located in shallow depth. The algorithm of this method is based on the Matching Pursuit (MP) that is a technique for non-orthogonal signal decomposition using dictionary of functions. As the dictionary of function, a wave-based dictionary constructed by taking account of scattering mechanisms of electromagnetic (EM) wave by rough surfaces is employed. Through numerical simulations, performance of ground clutter reduction is evaluated. The results show that the proposed method has good performance and is effective for GPR data preprocessing for discrimination of shallowly buried landmines.

  8. Radar cross sections of ground clutter at 95 GHz for summer and fall conditions

    Science.gov (United States)

    Wellman, R. J.; Hutchins, D. R.; Silvious, J. L.; Dropkin, H.; Goldman, G.; Nemarich, J.; Wikner, D. A.; Dahlstrom, R. K.

    1993-11-01

    Radar cross section (RCS) measurements were made on an extensively instrumented ground-clutter patch over a period of one month from late summer to early fall. The instrumentation allowed collection of a full set of data on meteorological conditions, solar flux, and soil moisture content. The RCS measurements were made using a 95-GHz, polarimetric, monopulse instrumentation radar. The radar is all solid-state, coherent, frequency steppable over a 640-MHz bandwidth, and completely polarimetric for linearly or circularly polarized radiation. The clutter area measured was located in Grayling, Michigan, and consisted of a rectangular patch of ground, 50 by 100 m in area, at a range of about 100 to 250 m from the radar. The clutter patch included areas of bare sandy ground, short grass, low shrubs, evergreen trees, and deciduous trees and was similar to a NATO European environment. A wide range of atmospheric conditions were observed over the measurement period, including a few days of measurable snowfall. The paper describes analysis of the effects of different clutter types and different atmospheric conditions on the measured RCS of the clutter patch.

  9. Comparative analysis of clutter suppression techniques for landmine detection using ground-penetrating radar

    Science.gov (United States)

    Yoldemir, Ahmet Burak; Gürcan, Rıdvan; Kaplan, Gülay Büyükaksoy; Sezgin, Mehmet

    2011-06-01

    In this study, we provide an extensive comparison of different clutter suppression techniques that are proposed to enhance ground penetrating radar (GPR) data. Unlike previous studies, we directly measure and present the effect of these preprocessing algorithms on the detection performance. Basic linear prediction algorithm is selected as the detection scheme and it is applied to real GPR data after applying each of the available clutter suppression techniques. All methods are tested on an extensive data set of different surrogate mines and other objects that are commonly encountered under the ground. Among several algorithms, singular value decomposition based clutter suppression stands out with its superior performance and low computational cost, which makes it practical to use in real-time applications.

  10. Ground-Vegetation Clutter Affects Phyllostomid Bat Assemblage Structure in Lowland Amazonian Forest.

    Directory of Open Access Journals (Sweden)

    Rodrigo Marciente

    Full Text Available Vegetation clutter is a limiting factor for bats that forage near ground level, and may determine the distribution of species and guilds. However, many studies that evaluated the effects of vegetation clutter on bats have used qualitative descriptions rather than direct measurements of vegetation density. Moreover, few studies have evaluated the effect of vegetation clutter on a regional scale. Here, we evaluate the influence of the physical obstruction of vegetation on phyllostomid-bat assemblages along a 520 km transect in continuous Amazonian forest. We sampled bats using mist nets in eight localities during 80 nights (3840 net-hours and estimated the ground-vegetation density with digital photographs. The total number of species, number of animalivorous species, total number of frugivorous species, number of understory frugivorous species, and abundance of canopy frugivorous bats were negatively associated with vegetation clutter. The bat assemblages showed a nested structure in relation to degree of clutter, with animalivorous and understory frugivorous bats distributed throughout the vegetation-clutter gradient, while canopy frugivores were restricted to sites with more open vegetation. The species distribution along the gradient of vegetation clutter was not closely associated with wing morphology, but aspect ratio and wing load differed between frugivores and animalivores. Vegetation structure plays an important role in structuring assemblages of the bats at the regional scale by increasing beta diversity between sites. Differences in foraging strategy and diet of the guilds seem to have contributed more to the spatial distribution of bats than the wing characteristics of the species alone.

  11. An improved MTI filter for ground clutter reduction in UAV classification

    Science.gov (United States)

    Wan, Fangyuan; Liu, Qinglai; Wang, Chen; Guo, Xin; Lin, Zhiping

    2017-06-01

    In recent years, Unmanned Aerial Vehicles (UAVs) have increasingly been used in many civil applications. However, they also pose a significant threat in restricted zones. Radar can be used to detect and discriminate UAVs. Due to the low flying altitude of the UAVs, it is found that the radar signals also include some unwanted echoes, reflected by building, ground, trees and grasses etc. Consequently, it has not been possible to get the clean UAVs characteristics for further classification. In this paper, the MTI filter is applied to cancel the ground clutter and based this, an improved MTI filter is further proposed. Compared with the traditional MTI filter, the improved one significantly enhances ground clutter rejection capability while maintaining most of the target power. As the result, the cleaner UAVs classification characteristics can be obtained. The effectiveness of the proposed method has been verified by an experimental CW radar dataset, collected from a helicopter UAV.

  12. Detection of Aircraft Embedded in Ground Clutter by Means of Non-Doppler X-band Radar

    Science.gov (United States)

    Hwang, Seongin; Ishii, Seishiro; Sayama, Shuji; Sekine, Matsuo

    It is reported that various radar clutter obey a Weibull distribution under certain conditions. To suppress such Weibull-distributed clutter, a new adaptive method was proposed by the present author. In this method, the parameters of the Weibull distribution and the threshold level for an adaptive Constant False Alarm Rate (CFAR) detector are determined by calculating the variance before it passes through a logarithmic amplifier. To apply this new method to practical problems observed by an X-band radar, a computer simulation are made for a finite number of samples in order to obtain the CFAR maintenance in Weibull radar clutter. Finally an improvement value of target-to-clutter ratio 30.07 dB was obtained for the detection of an aircraft embedded in ground clutter.

  13. Detection of Ground Clutter from Weather Radar Using a Dual-Polarization and Dual-Scan Method

    Directory of Open Access Journals (Sweden)

    Mohammad-Hossein Golbon-Haghighi

    2016-06-01

    Full Text Available A novel dual-polarization and dual-scan (DPDS classification algorithm is developed for clutter detection in weather radar observations. Two consecutive scans of dual-polarization radar echoes are jointly processed to estimate auto- and cross-correlation functions. Discriminants are then defined and estimated in order to separate clutter from weather based on their physical and statistical properties. An optimal Bayesian classifier is used to make a decision on clutter presence from the estimated discriminant functions. The DPDS algorithm is applied to the data collected with the KOUN polarimetric radar and compared with the existing detection methods. It is shown that the DPDS algorithm yields a higher probability of detection and lower false alarm rate in clutter detection.

  14. Clutter discrimination algorithm simulation in pulse laser radar imaging

    Science.gov (United States)

    Zhang, Yan-mei; Li, Huan; Guo, Hai-chao; Su, Xuan; Zhu, Fule

    2015-10-01

    Pulse laser radar imaging performance is greatly influenced by different kinds of clutter. Various algorithms are developed to mitigate clutter. However, estimating performance of a new algorithm is difficult. Here, a simulation model for estimating clutter discrimination algorithms is presented. This model consists of laser pulse emission, clutter jamming, laser pulse reception and target image producing. Additionally, a hardware platform is set up gathering clutter data reflected by ground and trees. The data logging is as clutter jamming input in the simulation model. The hardware platform includes a laser diode, a laser detector and a high sample rate data logging circuit. The laser diode transmits short laser pulses (40ns FWHM) at 12.5 kilohertz pulse rate and at 905nm wavelength. An analog-to-digital converter chip integrated in the sample circuit works at 250 mega samples per second. The simulation model and the hardware platform contribute to a clutter discrimination algorithm simulation system. Using this system, after analyzing clutter data logging, a new compound pulse detection algorithm is developed. This new algorithm combines matched filter algorithm and constant fraction discrimination (CFD) algorithm. Firstly, laser echo pulse signal is processed by matched filter algorithm. After the first step, CFD algorithm comes next. Finally, clutter jamming from ground and trees is discriminated and target image is produced. Laser radar images are simulated using CFD algorithm, matched filter algorithm and the new algorithm respectively. Simulation result demonstrates that the new algorithm achieves the best target imaging effect of mitigating clutter reflected by ground and trees.

  15. Exponential Decay in Windblown Radar Ground Clutter Doppler Spectra: Multifrequency Measurements and Model.

    Science.gov (United States)

    2007-11-02

    Reese Straw, William Dustin, Carol Bernhard, Joanne Bradley and Bob Graham-Munn. The manuscript was skillfully prepared by Pat DeCuir and kindly and...spreading of Ot° rees in Doppler, i.e., j^Krees’ Pto^dv = °trees- so Krees’ Ptot^ represents the normalized density of windblown tree clutter power

  16. A Ground Clutter Cancellation Algorithm for Noise Radar%一种噪声雷达地杂波消除算法

    Institute of Scientific and Technical Information of China (English)

    靳晓艳; 李伟

    2016-01-01

    Due to its excellent anti⁃interference performance and low intercept rate,noise radar has great apply potential in both military and civilian fields.In solve the problem of ground clutter wave cancellation in noise radar,an algorithm based on clutter base orthogonalization is proposed.In this algorithm,receive signal is put into a lattice filter,in order to fit the unknown or time⁃varying statis⁃tics characteristic of the ground clutter.And the parameters of filter are adjusted adaptively.Simulation results indicate that the proposed algorithm not only provides good cancellation effect to the ground clutter,but also can effectively suppress the direct signal.%噪声雷达因其优异的抗干扰性能和低截获概率,在军事和民用领域均具有着巨大的应用潜力。针对噪声雷达地杂波消除困难的问题,提出了一种基于杂波基向量正交化的算法,该算法通过将接收信号输入格形滤波器,并自适应地调整滤波器的参数,以适应地面杂波未知的或随时间变换的统计特性,从而实现最优滤波。仿真结果表明,所提算法不仅对地杂波具有很好的消除效果,与此同时也能够有效抑制直达波。

  17. A patterned and un-patterned minefield detection in cluttered environments using Markov marked point process

    Science.gov (United States)

    Trang, Anh; Agarwal, Sanjeev; Regalia, Phillip; Broach, Thomas; Smith, Thomas

    2007-04-01

    A typical minefield detection approach is based on a sequential processing employing mine detection and false alarm rejection followed by minefield detection. The current approach does not work robustly under different backgrounds and environment conditions because target signature changes with time and its performance degrades in the presence of high density of false alarms. The aim of this research will be to advance the state of the art in detection of both patterned and unpatterned minefield in high clutter environments. The proposed method seeks to combine false alarm rejection module and the minefield detection module of the current architecture by spatial-spectral clustering and inference module using a Markov Marked Point Process formulation. The approach simultaneously exploits the feature characteristics of the target signature and spatial distribution of the targets in the interrogation region. The method is based on the premise that most minefields can be characterized by some type of distinctive spatial distribution of "similar" looking mine targets. The minefield detection problem is formulated as a Markov Marked Point Process (MMPP) where the set of possible mine targets is divided into a possibly overlapping mixture of targets. The likelihood of the minefield depends simultaneously on feature characteristics of the target and their spatial distribution. A framework using "Belief Propagation" is developed to solve the minefield inference problem based on MMPP. Preliminary investigation using simulated data shows the efficacy of the approach.

  18. Performance limits for exo-clutter Ground Moving Target Indicator (GMTI) radar.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2010-09-01

    The performance of a Ground Moving Target Indicator (GMTI) radar system depends on a variety of factors, many which are interdependent in some manner. It is often difficult to 'get your arms around' the problem of ascertaining achievable performance limits, and yet those limits exist and are dictated by physics. This report identifies and explores those limits, and how they depend on hardware system parameters and environmental conditions. Ultimately, this leads to a characterization of parameters that offer optimum performance for the overall GMTI radar system. While the information herein is not new to the literature, its collection into a single report hopes to offer some value in reducing the 'seek time'.

  19. Comparison of PCA and ICA based clutter reduction in GPR systems for anti-personal landmine detection

    DEFF Research Database (Denmark)

    Karlsen, Brian; Larsen, Jan; Sørensen, Helge Bjarup Dissing;

    2001-01-01

    This paper presents statistical signal processing approaches for clutter reduction in stepped-frequency ground penetrating radar (SF-GPR) data. In particular, we suggest clutter/signal separation techniques based on principal and independent component analysis (PCA/ICA). The approaches are succes...

  20. Denoising and Back Ground Clutter of Video Sequence using Adaptive Gaussian Mixture Model Based Segmentation for Human Action Recognition

    Directory of Open Access Journals (Sweden)

    Shanmugapriya. K

    2014-01-01

    Full Text Available The human action recognition system first gathers images by simply querying the name of the action on a web image search engine like Google or Yahoo. Based on the assumption that the set of retrieved images contains relevant images of the queried action, we construct a dataset of action images in an incremental manner. This yields a large image set, which includes images of actions taken from multiple viewpoints in a range of environments, performed by people who have varying body proportions and different clothing. The images mostly present the “key poses” since these images try to convey the action with a single pose. In existing system to support this they first used an incremental image retrieval procedure to collect and clean up the necessary training set for building the human pose classifiers. There are challenges that come at the expense of this broad and representative data. First, the retrieved images are very noisy, since the Web is very diverse. Second, detecting and estimating the pose of humans in still images is more difficult than in videos, partly due to the background clutter and the lack of a foreground mask. In videos, foreground segmentation can exploit motion cues to great benefit. In still images, the only cue at hand is the appearance information and therefore, our model must address various challenges associated with different forms of appearance. Therefore for robust separation, in proposed work a segmentation algorithm based on Gaussian Mixture Models is proposed which is adaptive to light illuminations, shadow and white balance is proposed here. This segmentation algorithm processes the video with or without noise and sets up adaptive background models based on the characteristics also this method is a very effective technique for background modeling which classifies the pixels of a video frame either background or foreground based on probability distribution.

  1. PALSAR ground data processing

    Science.gov (United States)

    Frick, Heinrich; Palsetia, Marzban; Carande, Richard; Curlander, James C.

    2002-02-01

    The upcoming launches of new satellites like ALOS, Envisat, Radarsat2 and ECHO will pose a significant challenge for many ground stations, namely to integrate new SAR processing software into their existing systems. Vexcel Corporation in Boulder, Colorado, has built a SAR processing system, named APEX -Suite, for spaceborne SAR satellites that can easily be expanded for the next generation of SAR satellites. APEX-Suite includes an auto-satellite-detecting Level 0 Processor that includes bit-error correction, data quality characterization, and as a unique feature, a sophisticated and very accurate Doppler centroid estimator. The Level 1 processing is divided into the strip mode processor FOCUST, based on the well-proven range-Doppler algorithm, and the SWATHT ScanSAR processor that uses the Chirp Z Trans-form algorithm. A high-accuracy ortho-rectification processor produces systematic and precision corrected Level 2 SAR image pro ducts. The PALSAR instrument is an L-band SAR with multiple fine and standard resolution beams in strip mode, and several wide-swath ScanSAR modes. We will address the adaptation process of Vexcel's APEX-Suite processing system for the PALSAR sensor and discuss image quality characteristics based on processed simulated point target phase history data.

  2. Spacelab Ground Processing

    Science.gov (United States)

    Scully, Edward J.; Gaskins, Roger B.

    1982-02-01

    Spacelab (SL) ground processing is active at the Kennedy Space Center (KSC). The palletized payload for the second Shuttle launch is staged and integrated with interface verification active. The SL Engineering Model is being assembled for subsequent test and checkout activities. After delivery of SL flight elements from Europe, prelaunch operations for the first SL flight start with receipt of the flight experiment packages and staging of the SL hardware. Experiment operations consist of integrating the various experiment elements into the SL racks, floors and pallets. Rack and floor assemblies with the experiments installed, are integrated into the flight module. Aft end-cone installation, pallet connections, and SL subsystems interface verifications are accomplished, and SL-Orbiter interfaces verified. The Spacelab cargo is then transferred to the Orbiter Processing Facility (OPF) in a controlled environment using a canister/transporter. After the SL is installed into the Orbiter payload bay, physical and functional integrity of all payload-to-Orbiter interfaces are verified and final close-out operations conducted. Spacelab payload activities at the launch pad are minimal with the payload bay doors remaining closed. Limited access is available to the module through the Spacelab Transfer Tunnel. After mission completion, the SL is removed from the Orbiter in the OPF and returned to the SL processing facility for experiment equipment removal and reconfiguration for the subsequent mission.

  3. Sea clutter scattering, the K distribution and radar performance

    CERN Document Server

    Ward, Keith; Watts, Simon

    2013-01-01

    Sea Clutter: Scattering, the K Distribution and Radar Performance, 2nd Edition gives an authoritative account of our current understanding of radar sea clutter. Topics covered include the characteristics of radar sea clutter, modelling radar scattering by the ocean surface, statistical models of sea clutter, the simulation of clutter and other random processes, detection of small targets in sea clutter, imaging ocean surface features, radar detection performance calculations, CFAR detection, and the specification and measurement of radar performance. The calculation of the performance of pract

  4. A Clutter Suppression Approach for SAR-GMTI Based on Dual-channel DPCA

    Directory of Open Access Journals (Sweden)

    Wang Xiao-yang

    2014-04-01

    Full Text Available The Displaced Phase Center Antenna (DPCA technology, a particular form of Space Time Adaptive Processing (STAP, has been widely used in Synthetic Aperture Radar Ground Moving Target Indication (SAR-GMTI. The GMTI performance depends on the capability of clutter rejection but the traditional DPCA technology operated in the complex image domain does not have the appropriate clutter rejection capability for urban areas with strong scattering stationary objects. Hence, interferometry phase is used to weight the DPCA magnitude nonlinearly, and a weighted DPCA clutter rejection approach is proposed, which reduces the interference from residual phase difference. The experimental results suggest that the new approach can improve the clutter rejection compared with the conventional DPCA.

  5. Comparison of PCA and ICA based clutter reduction in GPR systems for anti-personal landmine detection

    OpenAIRE

    Karlsen, Brian; Larsen, Jan; Sørensen, Helge Bjarup Dissing; Jakobsen, Kaj Bjarne

    2001-01-01

    This paper presents statistical signal processing approaches for clutter reduction in stepped-frequency ground penetrating radar (SF-GPR) data. In particular, we suggest clutter/signal separation techniques based on principal and independent component analysis (PCA/ICA). The approaches are successfully evaluated and compared on a real SF-GPR time-series. Field-test data are acquired using a monostatic S-band rectangular waveguide antenna.

  6. Suppression of Clutter Near Port by S-Band Radar

    Science.gov (United States)

    Ishii, Seishiro; Sayama, Syuji

    It was reported that various radar clutters obey a Weibull distribution under certain conditions. To suppress such Weibull-distributed clutter, a new adaptive method was proposed by the present authors. In this method, the parameters of the Weibull distribution and the threshold level for an adaptive Constant False Alarm Rate (CFAR) detector are determined by calculating the variance after it passed through a logarithmic amplifier. To apply this new method to practical problems observed by an S-band radar, computer simulation were made for a finite number of samples in order to obtain the CFAR maintenance in Weibull radar clutter which was including sea clutter and ground clutter from a variety of terrain near the port. Finally an improvement value of target-to-clutter ratio 49.5dB was obtained for the detection of ships embedded in sea clutter near the port.

  7. Dynamic Singularity Spectrum Distribution of Sea Clutter

    Science.gov (United States)

    Xiong, Gang; Yu, Wenxian; Zhang, Shuning

    2015-12-01

    The fractal and multifractal theory have provided new approaches for radar signal processing and target-detecting under the background of ocean. However, the related research mainly focuses on fractal dimension or multifractal spectrum (MFS) of sea clutter. In this paper, a new dynamic singularity analysis method of sea clutter using MFS distribution is developed, based on moving detrending analysis (DMA-MFSD). Theoretically, we introduce the time information by using cyclic auto-correlation of sea clutter. For transient correlation series, the instantaneous singularity spectrum based on multifractal detrending moving analysis (MF-DMA) algorithm is calculated, and the dynamic singularity spectrum distribution of sea clutter is acquired. In addition, we analyze the time-varying singularity exponent ranges and maximum position function in DMA-MFSD of sea clutter. For the real sea clutter data, we analyze the dynamic singularity spectrum distribution of real sea clutter in level III sea state, and conclude that the radar sea clutter has the non-stationary and time-varying scale characteristic and represents the time-varying singularity spectrum distribution based on the proposed DMA-MFSD method. The DMA-MFSD will also provide reference for nonlinear dynamics and multifractal signal processing.

  8. 机载气象雷达下和差波束抑制地杂波研究%Ground Clutter Suppression for Airborne Weather Radar Based on Sum and Difference Beam

    Institute of Scientific and Technical Information of China (English)

    庄健; 朱岱寅

    2014-01-01

    A ground clutter suppression method based on sum and difference beam of radar echo signal is proposed,which can be used to depress the clutter when airborne weather radar operates in weather mode. First,the spatial model of the aircraft position as well as the meteorology and the ground clutter in the geo-centric coordinate system is set up.The pulse signals are generated by the airborne weather radar.The echo information of meteorology target and clutter inside the beam scanning range are calculated by the meteoro-logical radar equation.According to the difference of the position and angle between the meteorology and clutter,the ground clutter is depressed without missing the meteorological information using the sum and difference beam algorithm.The validity of the method is verified by using the simulation data.%针对机载气象雷达气象模式下的地杂波抑制研究,提出利用雷达回波信号的和差波束方法加以抑制。首先建立地心坐标系下飞机位置和气象与地杂波空间模型,然后通过机载气象雷达发射脉冲信号,利用气象雷达方程计算波束扫描范围内的气象目标和地杂波的回波功率信息。根据气象与地杂波所处雷达波束中心位置和角度不同的特性,利用和差波束方法抑制地杂波,同时气象信息不会有太大损耗。经过仿真数据验证,该方法能够有效地剔除地杂波,保留气象信息。

  9. 基于运动目标检测的同步轨道星-空双站SAR杂波特性分析%Analysis of Geosynchronous Satellite-Air Bistatic SAR Clutter Characteristics from the Viewpoint of Ground Moving Target Indication

    Institute of Scientific and Technical Information of China (English)

    张丹丹; 仇晓兰; 胡东辉; 丁赤飚

    2013-01-01

    同步轨道星-空双站SAR构型下(卫星作为发射端、浮空器作为接收端),为了应用空时自适应处理(Space Time Adaptive Processing, STAP)方法更好地抑制杂波,进行地面慢速运动目标检测,有必要分析杂波特性。该文从地面运动目标检测角度出发,建立了同步轨道星-空双站 SAR 杂波特性的理论模型,分析了杂波的角度-多普勒轨迹的距离依赖性特点,仿真实验证明了模型建立和理论分析的正确性。该文的理论模型和分析结论揭示了同步轨道星-空双SAR这一新模式下的杂波特性,为该模式下地面运动目标检测方法的选择和研究奠定了理论基础。%Considering the geometry of geosynchronous satellite-air bistatic Synthetic Aperture Radar (SAR) where the geosynchronous satellite is the transmitter and the aerostat is the receiver, to suppress clutter and detect a slow-moving target using Space-Time Adaptive Processing (STAP), it is necessary to analyze the clutter characteristics. From the viewpoint of a ground moving target indication, a theoretical model of the clutter characteristics considering the geometry of geosynchronous satellite-space bistatic SAR is analyzed and established in this study; in particular, the range-dependence characteristics of the angle-Doppler curve of the clutter is analyzed. Finally, the simulation verifies the correctness of the analysis. The theoretical model described and the conclusion presented in this paper indicate the clutter characteristics of the new geosynchronous satellite-air bistatic SAR mode and provide a theoretical basis for the selection and research of a ground moving target indication method for use in this mode.

  10. Decorrelating Clutter Statistics for Long Integration Time SAR Imaging

    Science.gov (United States)

    Leanza, Antonio; Monti Guarnieri, Andrea; Recchia, Andrea; Broquetas Ibars, Antoni; Ruiz Rodon, Josep

    2015-05-01

    It is presented an experiment aimed to assess and eventually complement the Billingsley Internal Clutter Motion (ICM) model for long integration time SAR imaging. Exploiting a real-aperture rotating antenna Ground-Based RADAR, observations of rural areas in different periods of the year have been performed. The collected data, obtained from two different acquisition modes, have been processed to obtain short-term and long-term clutter de-correlation analysis. The results obtained revealed interesting aspects of the phenomenon. In particular, it can be observed that the process is non-stationary with time, say minutes to hours, and that DC/AC ratio follows a day/night characteristic. Moreover, the results showed values of the AC component decay rate β higher than the foreseen ones in the considered spectral interval, which is quite below the one analyzed in the Billingsley experiment.

  11. Advanced signal processing method for ground penetrating radar feature detection and enhancement

    Science.gov (United States)

    Zhang, Yu; Venkatachalam, Anbu Selvam; Huston, Dryver; Xia, Tian

    2014-03-01

    This paper focuses on new signal processing algorithms customized for an air coupled Ultra-Wideband (UWB) Ground Penetrating Radar (GPR) system targeting highway pavements and bridge deck inspections. The GPR hardware consists of a high-voltage pulse generator, a high speed 8 GSps real time data acquisition unit, and a customized field-programmable gate array (FPGA) control element. In comparison to most existing GPR system with low survey speeds, this system can survey at normal highway speed (60 mph) with a high horizontal resolution of up to 10 scans per centimeter. Due to the complexity and uncertainty of subsurface media, the GPR signal processing is important but challenging. In this GPR system, an adaptive GPR signal processing algorithm using Curvelet Transform, 2D high pass filtering and exponential scaling is proposed to alleviate noise and clutter while the subsurface features are preserved and enhanced. First, Curvelet Transform is used to remove the environmental and systematic noises while maintain the range resolution of the B-Scan image. Then, mathematical models for cylinder-shaped object and clutter are built. A two-dimension (2D) filter based on these models removes clutter and enhances the hyperbola feature in a B-Scan image. Finally, an exponential scaling method is applied to compensate the signal attenuation in subsurface materials and to improve the desired signal feature. For performance test and validation, rebar detection experiments and subsurface feature inspection in laboratory and field configurations are performed.

  12. RADAR HRR PROFILING FOR GROUND MOVING TARGET USING PHASE-CODED AND HOPPED-FREQUENCY WAVEFORMS

    Institute of Scientific and Technical Information of China (English)

    Li Yan; Wang Changming

    2007-01-01

    To obtain the radar High Range Resolution (HRR) profile of the slowly moving ground target in strong clutter background, the Phase-Coded Hopped-Frequency (PCHF) waveform is proposed. By multiple-bursts coherent processing, the HRR profile synthesis, target velocity compensation and clutter compression can be accomplished simultaneously. The new waveform is shown to have good ability to suppress ground clutter and good Electronic Counter-CounterMeasures (ECCM) ability as well. The clutter compression performance of the proposed method is verified by the numerical results.

  13. Computational models for synthetic marine infrared clutter

    Science.gov (United States)

    Constantikes, Kim T.; Zysnarski, Adam H.

    1996-06-01

    The next generation of ship defense missiles will need to engage stealthy, passive, sea-skimming missiles. Detection and guidance will occur against a background of sea surface and horizon which can present significant clutter problems for infrared seekers, particularly when targets are comparatively dim. We need a variety of sea clutter models: statistical image models for signal processing algorithm design, clutter occurrence models for systems effectiveness assessment, and constructive image models for synthesizing very large field-of-view (FOV) images with high spatial and temporal resolution. We have implemented and tested such a constructive model. First principle models of water waves and light transport provide a computationally intensive clutter model implemented as a raytracer. Our models include sea, sky, and solar radiance; reflectance; attenuating atmospheres; constructive solid geometry targets; target and water wave dynamics; and simple sensor image formation.

  14. Doppler characteristics of sea clutter.

    Energy Technology Data Exchange (ETDEWEB)

    Raynal, Ann Marie; Doerry, Armin Walter

    2010-06-01

    Doppler radars can distinguish targets from clutter if the target's velocity along the radar line of sight is beyond that of the clutter. Some targets of interest may have a Doppler shift similar to that of clutter. The nature of sea clutter is different in the clutter and exo-clutter regions. This behavior requires special consideration regarding where a radar can expect to find sea-clutter returns in Doppler space and what detection algorithms are most appropriate to help mitigate false alarms and increase probability of detection of a target. This paper studies the existing state-of-the-art in the understanding of Doppler characteristics of sea clutter and scattering from the ocean to better understand the design and performance choices of a radar in differentiating targets from clutter under prevailing sea conditions.

  15. Space-time clutter model for airborne bistatic radar with non-Gaussian statistics

    Institute of Scientific and Technical Information of China (English)

    Duan Rui; Wang Xuegang; Yiang Chaoshu; Chen Zhuming

    2009-01-01

    To validate the potential space-time adaptive processing (STAP) algorithms for airborne bistatic radar clutter suppression under nonstationary and non-Gaussian clutter environments, a statistically non-Gaussian, space-time clutter model in varying bistatic geometrical scenarios is presented. The inclusive effects of the model contain the range dependency of bistatic clutter spectrum and clutter power variation in range-angle cells. To capture them, a new approach to coordinate system conversion is initiated into formulating bistatic geometrical model, and the bistatic non-Gaussian amplitude clutter representation method based on a compound model is introduced. The veracity of the geometrical model is validated by using the bistatie configuration parameters of multi-channel airborne radar measurement (MCARM) experiment. And simulation results manifest that the proposed model can accurately shape the space-time clutter spectrum tied up with specific airborne bistatic radar scenario and can characterize the heterogeneity of clutter amplitude distribution in practical clutter environments.

  16. Clutter in the GMTI range-velocity map.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2009-04-01

    Ground Moving Target Indicator (GMTI) radar maps echo data to range and range-rate, which is a function of a moving target's velocity and its position within the antenna beam footprint. Even stationary clutter will exhibit an apparent motion spectrum and can interfere with moving vehicle detections. Consequently it is very important for a radar to understand how stationary clutter maps into radar measurements of range and velocity. This mapping depends on a wide variety of factors, including details of the radar motion, orientation, and the 3-D topography of the clutter.

  17. Limits to Clutter Cancellation in Multi-Aperture GMTI Data

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bickel, Douglas L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

    Multi-aperture or multi-subaperture antennas are fundamental to Ground Moving Target Indicator (GMTI) radar systems in order to detect slow-moving targets with Doppler characteristics similar to clutter. Herein we examine the performance of several subaperture architectures for their clutter cancelling performance. Significantly, more antenna phase centers isn’t always better, and in fact is sometimes worse, for detecting targets.

  18. AN APPROACH TO SUPPRESS SHORT-RANGE CLUTTER FOR NON-SIDE LOOKING AIRBORNE RADAR

    Institute of Scientific and Technical Information of China (English)

    Li Ming; Liao Guisheng; Zhang Liang

    2011-01-01

    When the Airborne Early Warning (AEW) radar transmits medial or high Pulse Repetitive Frequency (PRF) signal,the range ambiguity occurs.The clutter of short-range clutter has serious range dependence problem for non-Side Looking Airborne Radar (non-SLAR).As a result,the clutter plus noise covariance matrix can not be estimated correctly,and the performance of clutter suppression obtained by Space-Time Adaptive Processing (STAP) degrades greatly.The uniform linear array has not elevation degrees; therefore,the short-range clutter can not be suppressed directly.A short-range clutter suppression method is proposed.The method first estimate the elevation angles of the ambiguous short-range gate,then eliminates short-range clutter by space time interpolation and adds moving target protection in the procedure.This method can suppress the short-range clutter well.Simulation results show the validity of the method.

  19. Advanced planning for ISS payload ground processing

    Science.gov (United States)

    Page, Kimberly A.

    2000-01-01

    Ground processing at John F. Kennedy Space Center (KSC) is the concluding phase of the payload/flight hardware development process and is the final opportunity to ensure safe and successful recognition of mission objectives. Planning for the ground processing of on-orbit flight hardware elements and payloads for the International Space Station is a responsibility taken seriously at KSC. Realizing that entering into this operational environment can be an enormous undertaking for a payload customer, KSC continually works to improve this process by instituting new/improved services for payload developer/owner, applying state-of-the-art technologies to the advanced planning process, and incorporating lessons learned for payload ground processing planning to ensure complete customer satisfaction. This paper will present an overview of the KSC advanced planning activities for ISS hardware/payload ground processing. It will focus on when and how KSC begins to interact with the payload developer/owner, how that interaction changes (and grows) throughout the planning process, and how KSC ensures that advanced planning is successfully implemented at the launch site. It will also briefly consider the type of advance planning conducted by the launch site that is transparent to the payload user but essential to the successful processing of the payload (i.e. resource allocation, executing documentation, etc.) .

  20. Radar clutter classification

    Science.gov (United States)

    Stehwien, Wolfgang

    1989-11-01

    The problem of classifying radar clutter as found on air traffic control radar systems is studied. An algorithm based on Bayes decision theory and the parametric maximum a posteriori probability classifier is developed to perform this classification automatically. This classifier employs a quadratic discriminant function and is optimum for feature vectors that are distributed according to the multivariate normal density. Separable clutter classes are most likely to arise from the analysis of the Doppler spectrum. Specifically, a feature set based on the complex reflection coefficients of the lattice prediction error filter is proposed. The classifier is tested using data recorded from L-band air traffic control radars. The Doppler spectra of these data are examined; the properties of the feature set computed using these data are studied in terms of both the marginal and multivariate statistics. Several strategies involving different numbers of features, class assignments, and data set pretesting according to Doppler frequency and signal to noise ratio were evaluated before settling on a workable algorithm. Final results are presented in terms of experimental misclassification rates and simulated and classified plane position indicator displays.

  1. Maximum Likelihood Joint Tracking and Association in Strong Clutter

    Directory of Open Access Journals (Sweden)

    Leonid I. Perlovsky

    2013-01-01

    Full Text Available We have developed a maximum likelihood formulation for a joint detection, tracking and association problem. An efficient non-combinatorial algorithm for this problem is developed in case of strong clutter for radar data. By using an iterative procedure of the dynamic logic process “from vague-to-crisp” explained in the paper, the new tracker overcomes the combinatorial complexity of tracking in highly-cluttered scenarios and results in an orders-of-magnitude improvement in signal-to-clutter ratio.

  2. Maximum Likelihood Joint Tracking and Association in Strong Clutter

    Directory of Open Access Journals (Sweden)

    Leonid I. Perlovsky

    2013-01-01

    Full Text Available We have developed a maximum likelihood formulation for a joint detection, tracking and association problem. An efficient non‐combinatorial algorithm for this problem is developed in case of strong clutter for radar data. By using an iterative procedure of the dynamic logic process “from vague‐to‐crisp” explained in the paper, the new tracker overcomes the combinatorial complexity of tracking in highly‐cluttered scenarios and results in an orders‐of‐magnitude improvement in signal‐ to‐clutter ratio.

  3. Cooperative tracking of ground moving target using unmanned aerial vehicles in cluttered environment%复杂环境下多无人机协作式地面移动目标跟踪

    Institute of Scientific and Technical Information of China (English)

    王林; 彭辉; 朱华勇; 沈林成

    2011-01-01

    针对多无人机(UAV)协同地面移动目标跟踪问题展开研究.提出一种基于主动感知的问题求解框架,建立多UAV协同目标跟踪问题模型;在此基础上,采用分布式无色信息滤波实现目标状态融合估计与预测;然后,基于预测目标状态,结合滚动时域控制与遗传算法设计一种多UAV在线协同航迹规划算法.仿真结果表明:结合预测目标状态在线优化UAV航迹能够获得更好的目标跟踪性能.%We investigate the cooperative tracking of a ground moving target in a cluttered environment by using unmanned aerial vehicles(UAV). Firstly, a model the cooperative target tracking by UAV is developed based on active sensing;secondly, a distributed unscented information filter is built for the estimation fusion and the prediction of target states. Finally, an online trajectory planning algorithm based on the receding horizon control and the genetic algorithm is designed and implemented, with the predicted target states as the inputs to this planning algorithm. Numerical simulations demonstrate that the proposed method effectively improves the performance of target tracking.

  4. Detection of Weather Radar Clutter

    DEFF Research Database (Denmark)

    Bøvith, Thomas

    2008-01-01

    Weather radars provide valuable information on precipitation in the atmosphere but due to the way radars work, not only precipitation is observed by the weather radar. Weather radar clutter, echoes from non-precipitating targets, occur frequently in the data, resulting in lowered data quality....... Especially in the application of weather radar data in quantitative precipitation estimation and forecasting a high data quality is important. Clutter detection is one of the key components in achieving this goal. This thesis presents three methods for detection of clutter. The methods use supervised...... and precipitating and non-precipitating clouds. Another method uses the difference in the motion field of clutter and precipitation measured between two radar images. Furthermore, the direction of the wind field extracted from a weather model is used. The third method uses information about the refractive index...

  5. Innovative process rational choice grounding in organization

    OpenAIRE

    S.M. Illiashenko

    2015-01-01

    The aim of the article. The aim of the article is to investigate and scientifically to ground recommendations concerning choice of the rational structure and innovative process content, depending on innovative development potential in the organization and innovation radicalization degree, which provides to coordinate interconnection between SRCCW and innovations marketing at its stages for various innovative business types. The results of the analysis. The generalized scheme of organizati...

  6. Innovative process rational choice grounding in organization

    Directory of Open Access Journals (Sweden)

    S.M. Illiashenko

    2015-06-01

    Full Text Available The aim of the article. The aim of the article is to investigate and scientifically to ground recommendations concerning choice of the rational structure and innovative process content, depending on innovative development potential in the organization and innovation radicalization degree, which provides to coordinate interconnection between SRCCW and innovations marketing at its stages for various innovative business types. The results of the analysis. The generalized scheme of organization innovative activity is investigated. It characterizes interconnections between innovative process, innovative business and innovative strategies types. The peculiarities of the works conduct concerning innovative process distinguished types are confirmed by scheme: works essence, type (types of the innovative business, innovative strategy (strategies, which is realized. Recommendations concerning works conduct reasonability of the several stages in the innovative process for organizations, which have innovative business combined type, are suggested. Essence and content of SRRCW works and innovations marketing works are confirmed at the innovative and life cycle stages of the new product. Table of decisions is developed to choose innovative process variants, which are reasonably to realize by concrete organization, depending on subsystems constituents state of its innovative development potential and innovative product radicalization degree. The enlarged block-scheme of the algorithm to choose rational structure in the innovative process within one or every innovative projects, realized by organization, is investigated. The recommendations concerning estimation of the innovative processes possible simultaneous conduct with various or similar variants of the innovative process structures by formal procedures are developed. Conclusions and directions of further researches. Author’s studies together allow to increase validity and decrease risk to choose

  7. Ground Processing Affordability for Space Vehicles

    Science.gov (United States)

    Ingalls, John; Scott, Russell

    2011-01-01

    Launch vehicles and most of their payloads spend the majority of their time on the ground. The cost of ground operations is very high. So, why so often is so little attention given to ground processing during development? The current global space industry and economic environment are driving more need for efficiencies to save time and money. Affordability and sustainability are more important now than ever. We can not continue to treat space vehicles as mere science projects. More RLV's (Reusable Launch Vehicles) are being developed for the gains of reusability which are not available for ELV's (Expendable Launch Vehicles). More human-rated vehicles are being developed, with the retirement of the Space Shuttles, and for a new global space race, yet these cost more than the many unmanned vehicles of today. We can learn many lessons on affordability from RLV's. DFO (Design for Operations) considers ground operations during design, development, and manufacturing-before the first flight. This is often minimized for space vehicles, but is very important. Vehicles are designed for launch and mission operations. You will not be able to do it again if it is too slow or costly to get there. Many times, technology changes faster than space products such that what is launched includes outdated features, thus reducing competitiveness. Ground operations must be considered for the full product Lifecycle, from concept to retirement. Once manufactured, launch vehicles along with their payloads and launch systems require a long path of processing before launch. Initial assembly and testing always discover problems to address. A solid integration program is essential to minimize these impacts, as was seen in the Constellation Ares I-X test rocket. For RLV's, landing/recovery and post-flight turnaround activities are performed. Multi-use vehicles require reconfiguration. MRO (Maintenance, Repair, and Overhaul) must be well-planned--- even for the unplanned problems. Defect limits and

  8. Artificial Neural Network-Based Clutter Reduction Systems for Ship Size Estimation in Maritime Radars

    Directory of Open Access Journals (Sweden)

    Vicen-Bueno R

    2010-01-01

    Full Text Available The existence of clutter in maritime radars deteriorates the estimation of some physical parameters of the objects detected over the sea surface. For that reason, maritime radars should incorporate efficient clutter reduction techniques. Due to the intrinsic nonlinear dynamic of sea clutter, nonlinear signal processing is needed, what can be achieved by artificial neural networks (ANNs. In this paper, an estimation of the ship size using an ANN-based clutter reduction system followed by a fixed threshold is proposed. High clutter reduction rates are achieved using 1-dimensional (horizontal or vertical integration modes, although inaccurate ship width estimations are achieved. These estimations are improved using a 2-dimensional (rhombus integration mode. The proposed system is compared with a CA-CFAR system, denoting a great performance improvement and a great robustness against changes in sea clutter conditions and ship parameters, independently of the direction of movement of the ocean waves and ships.

  9. Ground robotic measurement of aeolian processes

    Science.gov (United States)

    Qian, Feifei; Jerolmack, Douglas; Lancaster, Nicholas; Nikolich, George; Reverdy, Paul; Roberts, Sonia; Shipley, Thomas; Van Pelt, R. Scott; Zobeck, Ted M.; Koditschek, Daniel E.

    2017-08-01

    Models of aeolian processes rely on accurate measurements of the rates of sediment transport by wind, and careful evaluation of the environmental controls of these processes. Existing field approaches typically require intensive, event-based experiments involving dense arrays of instruments. These devices are often cumbersome and logistically difficult to set up and maintain, especially near steep or vegetated dune surfaces. Significant advances in instrumentation are needed to provide the datasets that are required to validate and improve mechanistic models of aeolian sediment transport. Recent advances in robotics show great promise for assisting and amplifying scientists' efforts to increase the spatial and temporal resolution of many environmental measurements governing sediment transport. The emergence of cheap, agile, human-scale robotic platforms endowed with increasingly sophisticated sensor and motor suites opens up the prospect of deploying programmable, reactive sensor payloads across complex terrain in the service of aeolian science. This paper surveys the need and assesses the opportunities and challenges for amassing novel, highly resolved spatiotemporal datasets for aeolian research using partially-automated ground mobility. We review the limitations of existing measurement approaches for aeolian processes, and discuss how they may be transformed by ground-based robotic platforms, using examples from our initial field experiments. We then review how the need to traverse challenging aeolian terrains and simultaneously make high-resolution measurements of critical variables requires enhanced robotic capability. Finally, we conclude with a look to the future, in which robotic platforms may operate with increasing autonomy in harsh conditions. Besides expanding the completeness of terrestrial datasets, bringing ground-based robots to the aeolian research community may lead to unexpected discoveries that generate new hypotheses to expand the science

  10. Design of a Demonstrator of an Adaptive steerable Antenna system for removal of Interference, clutter, Jammer based on AWG &VSA

    Directory of Open Access Journals (Sweden)

    M Chakraborty

    2012-10-01

    Full Text Available Interfering, clutter and jamming systems are becoming an increasing concern to the military and security industries worldwide. To overcome these problems phase array antennas and adaptive beam forming systems offers a potential solution. STAP is an application of optimum and adaptive array processing algorithms to the radar problem of target detection in ground clutter and interference with pulse-Doppler waveforms.In this paper we have presented our work of designing a MVDR beam former receiver using AWG and VSA. The minimumvariance distortion less response (MVDR approach is very popular technic in array processing that generates some mean square error or values. When these values fed to the phase array antenna system results in electronic steering of antenna beam according to the weight vector generated.

  11. Global Infrasound Association Based on Probabilistic Clutter Categorization

    Science.gov (United States)

    Arora, Nimar; Mialle, Pierrick

    2016-04-01

    The IDC advances its methods and continuously improves its automatic system for the infrasound technology. The IDC focuses on enhancing the automatic system for the identification of valid signals and the optimization of the network detection threshold by identifying ways to refine signal characterization methodology and association criteria. An objective of this study is to reduce the number of associated infrasound arrivals that are rejected from the automatic bulletins when generating the reviewed event bulletins. Indeed, a considerable number of signal detections are due to local clutter sources such as microbaroms, waterfalls, dams, gas flares, surf (ocean breaking waves) etc. These sources are either too diffuse or too local to form events. Worse still, the repetitive nature of this clutter leads to a large number of false event hypotheses due to the random matching of clutter at multiple stations. Previous studies, for example [1], have worked on categorization of clutter using long term trends on detection azimuth, frequency, and amplitude at each station. In this work we continue the same line of reasoning to build a probabilistic model of clutter that is used as part of NETVISA [2], a Bayesian approach to network processing. The resulting model is a fusion of seismic, hydroacoustic and infrasound processing built on a unified probabilistic framework. References: [1] Infrasound categorization Towards a statistics based approach. J. Vergoz, P. Gaillard, A. Le Pichon, N. Brachet, and L. Ceranna. ITW 2011 [2] NETVISA: Network Processing Vertically Integrated Seismic Analysis. N. S. Arora, S. Russell, and E. Sudderth. BSSA 2013

  12. 海杂波测量定标的姿态修正数据处理方法%Data Processing Method of Posture Correction for Calibration of Sea Clutter Measurement

    Institute of Scientific and Technical Information of China (English)

    张玉石; 尹雅磊; 许心瑜; 李慧明; 张浙东; 吴振森

    2015-01-01

    The external calibration of shore-based sea clutter measurement radar faces the problems with influence of sea wave motion. This paper proposes a posture correction method based on a coordinate transformation. The proposed method which combines the radar signal acquisition process and radar antenna direction factor, can effectively solve the effect of sloshing on the accuracy of the external calibration. Using the external calibration trial data collected by L-band shore-based sea clutter measurement radar, the experimental results are analyzed and compared with posture correction improvement on the calibration accuracy. The results show that the proposed method can greatly improve the accuracy of the calibration and is important to provide technical support for universal adaptability of the real sea clutter data.%针对岸基海杂波测量雷达下视外定标海浪运动的影响问题,该文提出一种基于坐标变换的姿态修正方法,该方法结合雷达信号采集过程和雷达方向图因子,能够有效解决外定标过程中海面晃动对定标精度的影响。利用L波段岸基海杂波测量雷达获取的外定标试验数据,分析试验结果并对比姿态修正前后定标精度的改善效果,结果表明该方法可大大提高定标精度,可为改善岸基海杂波测量数据的普适性提供重要的技术支持。

  13. Clutter Moves in Old Age Homecare

    DEFF Research Database (Denmark)

    Lutz, Peter

    2010-01-01

    This chapter introduces the notion of clutter moves as an experimental heuristic for tracing how movement threads together a range of cluttered entities in old age homecare ecologies. In particular it is concerned with older people and their cluttered technologies. It is based on empirical data...... cites general household clutter as a hazard in the domestic environment. In such reports moving around with cluttered things tends to threaten a dangerous outcome for older people. But what other feasible vistas emerge when the analytical attention is focused explicitly on relational movements between...

  14. Inference-Based Surface Reconstruction of Cluttered Environments

    KAUST Repository

    Biggers, K.

    2012-08-01

    We present an inference-based surface reconstruction algorithm that is capable of identifying objects of interest among a cluttered scene, and reconstructing solid model representations even in the presence of occluded surfaces. Our proposed approach incorporates a predictive modeling framework that uses a set of user-provided models for prior knowledge, and applies this knowledge to the iterative identification and construction process. Our approach uses a local to global construction process guided by rules for fitting high-quality surface patches obtained from these prior models. We demonstrate the application of this algorithm on several example data sets containing heavy clutter and occlusion. © 2012 IEEE.

  15. SAR Ground Moving Target Indication Based on Relative Residue of DPCA Processing.

    Science.gov (United States)

    Xu, Jia; Huang, Zuzhen; Yan, Liang; Zhou, Xu; Zhang, Furu; Long, Teng

    2016-10-12

    For modern synthetic aperture radar (SAR), it has much more urgent demands on ground moving target indication (GMTI), which includes not only the point moving targets like cars, truck or tanks but also the distributed moving targets like river or ocean surfaces. Among the existing GMTI methods, displaced phase center antenna (DPCA) can effectively cancel the strong ground clutter and has been widely used. However, its detection performance is closely related to the target's signal-to-clutter ratio (SCR) as well as radial velocity, and it cannot effectively detect the weak large-sized river surfaces in strong ground clutter due to their low SCR caused by specular scattering. This paper proposes a novel method called relative residue of DPCA (RR-DPCA), which jointly utilizes the DPCA cancellation outputs and the multi-look images to improve the detection performance of weak river surfaces. Furthermore, based on the statistics analysis of the RR-DPCA outputs on the homogenous background, the cell average (CA) method can be well applied for subsequent constant false alarm rate (CFAR) detection. The proposed RR-DPCA method can well detect the point moving targets and distributed moving targets simultaneously. Finally, the results of both simulated and real data are provided to demonstrate the effectiveness of the proposed SAR/GMTI method.

  16. SAR Ground Moving Target Indication Based on Relative Residue of DPCA Processing

    Directory of Open Access Journals (Sweden)

    Jia Xu

    2016-10-01

    Full Text Available For modern synthetic aperture radar (SAR, it has much more urgent demands on ground moving target indication (GMTI, which includes not only the point moving targets like cars, truck or tanks but also the distributed moving targets like river or ocean surfaces. Among the existing GMTI methods, displaced phase center antenna (DPCA can effectively cancel the strong ground clutter and has been widely used. However, its detection performance is closely related to the target’s signal-to-clutter ratio (SCR as well as radial velocity, and it cannot effectively detect the weak large-sized river surfaces in strong ground clutter due to their low SCR caused by specular scattering. This paper proposes a novel method called relative residue of DPCA (RR-DPCA, which jointly utilizes the DPCA cancellation outputs and the multi-look images to improve the detection performance of weak river surfaces. Furthermore, based on the statistics analysis of the RR-DPCA outputs on the homogenous background, the cell average (CA method can be well applied for subsequent constant false alarm rate (CFAR detection. The proposed RR-DPCA method can well detect the point moving targets and distributed moving targets simultaneously. Finally, the results of both simulated and real data are provided to demonstrate the effectiveness of the proposed SAR/GMTI method.

  17. Knowledge-Aided STAP Processing for Ground Moving Target Indication Radar Using Multilook Data

    Directory of Open Access Journals (Sweden)

    Page Douglas

    2006-01-01

    Full Text Available Knowledge-aided space-time adaptive processing (KASTAP using multiple coherent processing interval (CPI radar data is described. The approach is based on forming earth-based clutter reflectivity maps to provide improved knowledge of clutter statistics in nonhomogeneous terrain environments. The maps are utilized to calculate predicted clutter covariance matrices as a function of range. Using a data set provided under the DARPA knowledge-aided sensor signal processing and expert reasoning (KASSPER Program, predicted distributed clutter statistics are compared to measured statistics to verify the accuracy of the approach. Robust STAP weight vectors are calculated using a technique that combines covariance tapering, adaptive estimation of gain and phase corrections, knowledge-aided prewhitening, and eigenvalue rescaling. Techniques to suppress large discrete returns, expected in urban areas, are also described. Several performance metrics are presented, including signal-to-interference-plus-noise ratio (SINR loss, target detections and false alarms, receiver operating characteristic (ROC curves, and tracking performance. The results show more than an order of magnitude reduction in false alarm density when compared to standard STAP processing.

  18. Methods of small slow moving targets detection in heavy sea clutter

    Directory of Open Access Journals (Sweden)

    O. D. Mrachkovsky

    2013-07-01

    Full Text Available The search for methods of small targets detection by marine radars is carried out in this paper. As a result of the sources analysis three promising group of methods are selected – adaptive methods based on the clutter amplitude spherically invariant random process representation, methods based on non stohastic clutter representation and methods based on orthogonal transformations. Separately, neural networks and clutter polarization properties are noticed. Most of researches consider compound Gaussian distribution for high resolution sea clutter data modeling. Adaptive CFAR algoritm developed by Kelly for Gaussian clutter was extended for spherical invariant random process. This algorithm can detect target in compound Gaussian clutter and ensure CFAR detection if covariance matrix is precisely known. Many researches proposed different methods of covariance matrix estimating using information from cells adjacent with cell under test. Progress in this field is moving to finding less computation cost but more precise methods of covariance matrix estimation. Further progress for small slow moving targets in heavy sea clutter detection can develop in 3 ways – improving covariance matrix estimation, exploiting not stochastic methods and finding best orthogonal transform for sea clutter Doppler spectrum describing.

  19. A bat inspired technique for clutter reduction in radar sounder systems

    Science.gov (United States)

    Carrer, L.; Bruzzone, L.

    2016-10-01

    Radar Sounders are valuable instruments for subsurface investigation. They are widely employed for the study of planetary bodies around the solar system. Due to their wide antenna beam pattern, off-nadir surface reflections (i.e. clutter) of the transmitted signal can compete with echoes coming from the subsurface thus masking them. Different strategies have been adopted for clutter mitigation. However, none of them proved to be the final solution for this specific problem. Bats are very well known for their ability in discriminating between a prey and unwanted clutter (e.g. foliage) by effectively employing their sonar. According to recent studies, big brown bats can discriminate clutter by transmitting two different carrier frequencies. Most interestingly, there are many striking analogies between the characteristics of the bat sonar and the one of a radar sounder. Among the most important ones, they share the same nadir acquisition geometry and transmitted signal type (i.e. linear frequency modulation). In this paper, we explore the feasibility of exploiting frequency diversity for the purpose of clutter discrimination in radar sounding by mimicking unique bats signal processing strategies. Accordingly, we propose a frequency diversity clutter reduction method based on specific mathematical conditions that, if verified, allow the disambiguation between the clutter and the subsurface signal to be performed. These analytic conditions depend on factors such as difference in central carrier frequencies, surface roughness and subsurface material properties. The method performance has been evaluated by different simulations of meaningful acquisition scenarios which confirm its clutter reduction effectiveness.

  20. A NEW METHOD TO COMPENSATE CLUTTER RANGE DEPENDENCE FOR FORWARD LOOKING AIRBORNE RADARS

    Institute of Scientific and Technical Information of China (English)

    Jiang Dongchu; He Fei

    2010-01-01

    The clutter direction-Doppler curves are not aligned on the near range bins for forward looking airborne radar. As a result,the performance of clutter suppression by Space-Time Adaptive Processing (STAP) degrades greatly because of the clutter range dependence. To deal with this problem,a new compensated method is proposed in this paper. The method rebuilds the clutter covariance matrix based on spatial high resolution Minimum Variance Distortionless Response (MVDR) spectrum,and then finds a matrix to transform the covariance matrix of short-range gate to the referred far-range gate. The method can compensate the clutter range dependence well. The simulation results show validity of the method.

  1. Clutter Moves in Old Age Homecare

    DEFF Research Database (Denmark)

    Lutz, Peter

    2010-01-01

    This chapter introduces the notion of clutter moves as an experimental heuristic for tracing how movement threads together a range of cluttered entities in old age homecare ecologies. In particular it is concerned with older people and their cluttered technologies. It is based on empirical data...... originating from an ethnographic study of old age homecare in the United States. Here the category of home clutter was revealed as more complex than it is commonly portrayed in popular or scholarly accounts, especially gerontology and geriatric–related literature on falling risks. This literature frequently...... cites general household clutter as a hazard in the domestic environment. In such reports moving around with cluttered things tends to threaten a dangerous outcome for older people. But what other feasible vistas emerge when the analytical attention is focused explicitly on relational movements between...

  2. Hardware in the loop simulation of arbitrary magnitude shaped correlated radar clutter

    CSIR Research Space (South Africa)

    Strydom, JJ

    2014-10-01

    Full Text Available This paper describes a simple process for the generation of arbitrary probability distributions of complex data with correlation from sample to sample, optimized for hardware in the loop radar environment simulation. Measured radar clutter is used...

  3. Kennedy Space Center Orion Processing Team Planning for Ground Operations

    Science.gov (United States)

    Letchworth, Gary; Schlierf, Roland

    2011-01-01

    Topics in this presentation are: Constellation Ares I/Orion/Ground Ops Elements Orion Ground Operations Flow Orion Operations Planning Process and Toolset Overview, including: 1 Orion Concept of Operations by Phase 2 Ops Analysis Capabilities Overview 3 Operations Planning Evolution 4 Functional Flow Block Diagrams 5 Operations Timeline Development 6 Discrete Event Simulation (DES) Modeling 7 Ground Operations Planning Document Database (GOPDb) Using Operations Planning Tools for Operability Improvements includes: 1 Kaizen/Lean Events 2 Mockups 3 Human Factors Analysis

  4. Subaperture clutter filter with CFAR signal detection

    Energy Technology Data Exchange (ETDEWEB)

    Ormesher, Richard C.; Naething, Richard M.

    2016-08-30

    The various technologies presented herein relate to the determination of whether a received signal comprising radar clutter further comprises a communication signal. The communication signal can comprise of a preamble, a data symbol, communication data, etc. A first portion of the radar clutter is analyzed to determine a radar signature of the first portion of the radar clutter. A second portion of the radar clutter can be extracted based on the radar signature of the first portion. Following extraction, any residual signal can be analyzed to retrieve preamble data, etc. The received signal can be based upon a linear frequency modulation (e.g., a chirp modulation) whereby the chirp frequency can be determined and the frequency of transmission of the communication signal can be based accordingly thereon. The duration and/or bandwidth of the communication signal can be a portion of the duration and/or the bandwidth of the radar clutter.

  5. An Ionospheric Es Layer Clutter Model and Suppression in HF Surfacewave Radar

    Directory of Open Access Journals (Sweden)

    Yajun Li

    2013-01-01

    Full Text Available This paper based on a fast implemented multiphase screen method using DFT puts forward an ionospheric Es layer clutter model and uses the newly developed dimensionality reduction space-time adaptive processing- (STAP- JDL algorithm to suppress Es layer clutter, which proves the validity of the proposed model. Firstly, the multiphase screen method was analyzed, and a fast algorithm using DFT was proposed. Then, based on the multiphase screen method and thorough simulation, we reached a conclusion of the high-frequency radio wave propagation’s fluctuation characteristics in the ionosphere. According to the results of the analysis, a new Es layer ionospheric clutter model was established and was compared with the measured data and verification was made. Finally, based on the built clutter model, JDL algorithm was applied to the high-frequency surface wave radar ionospheric clutter suppression, using the measured data to verify the validity of the model and algorithm. The simulation results showed that the built model can show the characteristics of the ionospheric Es layer clutter and that the JDL algorithm can suppress ionospheric Es layer clutter quite effectively.

  6. Cluttering

    Science.gov (United States)

    ... on December 4, 1955, in Levack, Ontario. Kenyon Martin Kenyon Martin, the basketball sensation who was named to the ... This Virginian congressman has served in the U.S. House of Representatives since 1981. The longtime supporter of ...

  7. Robot navigation in cluttered 3-D environments using preference-based fuzzy behaviors.

    Science.gov (United States)

    Shi, Dongqing; Collins, Emmanuel G; Dunlap, Damion

    2007-12-01

    Autonomous navigation systems for mobile robots have been successfully deployed for a wide range of planar ground-based tasks. However, very few counterparts of previous planar navigation systems were developed for 3-D motion, which is needed for both unmanned aerial and underwater vehicles. A novel fuzzy behavioral scheme for navigating an unmanned helicopter in cluttered 3-D spaces is developed. The 3-D navigation problem is decomposed into several identical 2-D navigation subproblems, each of which is solved by using preference-based fuzzy behaviors. Due to the shortcomings of vector summation during the fusion of the 2-D subproblems, instead of directly outputting steering subdirections by their own defuzzification processes, the intermediate preferences of the subproblems are fused to create a 3-D solution region, representing degrees of preference for the robot movement. A new defuzzification algorithm that steers the robot by finding the centroid of a 3-D convex region of maximum volume in the 3-D solution region is developed. A fuzzy speed-control system is also developed to ensure efficient and safe navigation. Substantial simulations have been carried out to demonstrate that the proposed algorithm can smoothly and effectively guide an unmanned helicopter through unknown and cluttered urban and forest environments.

  8. Sensitivity study for clutter from reticle seekers

    Science.gov (United States)

    Conant, John A.

    1993-08-01

    The occurrence of background clutter is an on-going issue in the development of electro- optical sensors and seekers. Clutter varies with many parameters, which makes it costly to utilize measured data. Modeled backgrounds must be tested, however, to determine if the clutter they generate is realistic. The study reported here was performed with several goals: (1) to develop a methodology for studying clutter; (2) to compare the clutter levels from different scene elements; (3) study variations in spectral bandpass and in atmospheric visibility; and, (4) to study the effect of varying model sophistication on clutter. The last goal is one which has not previously been studied, to our knowledge. These results give model developers guidance on what model elements deserve the most resources. The present study focused on a generic reticle seeker, such as would be used in a tactical missile. The backgrounds studied were of tree-lines horizons, sun-heated rocks, and broken clouds, in four spectral bands within the 1 to 12 micron infrared region. Atmospheric haze levels were varied from 1 km to 23 km visibility. For these computations, the order of importance to clutter levels was, (1) scene type, (2) model sophistication level, and (3) haze. Strong variations with spectral band were also noted, although bands could not be compared fairly.

  9. A Framework for Symmetric Part Detection in Cluttered Scenes

    Directory of Open Access Journals (Sweden)

    Tom Lee

    2015-07-01

    Full Text Available The role of symmetry in computer vision has waxed and waned in importance during the evolution of the field from its earliest days. At first figuring prominently in support of bottom-up indexing, it fell out of favour as shape gave way to appearance and recognition gave way to detection. With a strong prior in the form of a target object, the role of the weaker priors offered by perceptual grouping was greatly diminished. However, as the field returns to the problem of recognition from a large database, the bottom-up recovery of the parts that make up the objects in a cluttered scene is critical for their recognition. The medial axis community has long exploited the ubiquitous regularity of symmetry as a basis for the decomposition of a closed contour into medial parts. However, today’s recognition systems are faced with cluttered scenes and the assumption that a closed contour exists, i.e., that figure-ground segmentation has been solved, rendering much of the medial axis community’s work inapplicable. In this article, we review a computational framework, previously reported in [1–3], that bridges the representation power of the medial axis and the need to recover and group an object’s parts in a cluttered scene. Our framework is rooted in the idea that a maximally-inscribed disc, the building block of a medial axis, can be modelled as a compact superpixel in the image. We evaluate the method on images of cluttered scenes.

  10. Language planning disturbances in children who clutter or have learning disabilities.

    Science.gov (United States)

    van Zaalen-Op't Hof, Yvonne; Wijnen, Frank; Dejonckere, Philip

    2009-01-01

    The primary objective of this paper is to determine to what extent disturbances in the fluency of language production of children who clutter might be related to, or differ from difficulties in the same underlying processes of language formulation seen in children with learning disabilities. It is hypothesized that an increase in normal dysfluencies and sentence revisions in children who clutter reflect different neurolinguistic process to those of children with learning disabilities. To test this idea, 150 Dutch speaking children, aged 10;6 to 12;11 years, were divided in three groups (cluttering, learning difficulties and controls), and a range of speech and language variables were analysed. Results indicate differences in the underlying processes of language disturbances between children with cluttered speech and those with learning disabilities. Specifically, language production of children with learning disabilities was disturbed by problems at the conceptualizator and formulator stages of Levelt's language processing model, whilst language planning disturbances in children who clutter were considered to arise due to insufficient time to complete the editing phase of sentence structuring. These findings indicate that children who clutter can be differentiated from children with learning disabilities by both the number of main and secondary story plot elements and by the percentage of correct sentence structures.

  11. Grounding language processing on basic neurophysiological principles.

    Science.gov (United States)

    Friederici, Angela D; Singer, Wolf

    2015-06-01

    In animal models the neural basis of cognitive and executive processes has been studied extensively at various hierarchical levels from microcircuits to distributed functional networks. This work already provides compelling evidence that diverse cognitive functions are based on similar basic neuronal mechanisms. More recent data suggest that even cognitive functions realized only in human brains rely on these canonical neuronal mechanisms. Here we argue that language, like other cognitive functions, depends on distributed computations in specialized cortical areas forming large-scale dynamic networks and examine to what extent empirical results support this view.

  12. Bistatic MIMO Radar Clutter Suppression by Exploiting the Transmit Angle

    Directory of Open Access Journals (Sweden)

    Li Jun

    2014-04-01

    Full Text Available The transmit angle of bistatic radars can be obtained by introducing Multiple-Input Multiple-Output (MIMO radar techniques. The Three-Dimensional (3D clutter spectra, that is, the transmit angle, receive angle, and Doppler frequency, are introduced using the additional angle information to Space-Time Adaptive Processing (STAP. This study reviews the researches on bistatic MIMO-STAP. 3D space-time adaptive processing methods for airborne bistatic side-looking MIMO radars, such as 3D-LCMV, 3D-ACR, 3D-JDL, and 3D projection-based reduced dimensional STAP methods, are discussed. Simulation results show that the proposed methods can improve the small-sample support performance of range-dependent clutter suppression in bistatic side-looking MIMO radar. Finally, the results are summarized and the prospects of bistatic MIMO-STAP are discussed.

  13. Simulation of non-stationary ground motion processes (II)

    Institute of Scientific and Technical Information of China (English)

    LIANG Jian-wen

    2005-01-01

    This paper proposes a method for simulation of non-stationary ground motion processes having the identical statistical feature, time-dependent power spectrum, with a given ground motion record, on the basis of review of simulation of non-stationary ground motion processes. The method has the following advantages: the sample processes are non-stationary both in amplitude and frequency, and both the amplitude and frequency non-stationarity depend on the target power spectrum; the power spectrum of any sample process does not necessarily accord with the target power spectrum, but statistically, it strictly accords with the target power spectrum. Finally, the method is verified by simulation of one acceleration record in Landers earthquake.

  14. Adaptive Robust Waveform Selection for Unknown Target Detection in Clutter

    Institute of Scientific and Technical Information of China (English)

    Lu-Lu Wang; Hong-Qiang Wang; Yu-Liang Qin; Yong-Qiang Cheng

    2014-01-01

    @@@A basic assumption of most recently proposed waveform design algorithms is that the target impulse response is a known deterministic function or a stochastic process with a known power spectral density (PSD). However, it is well-known that a target impulse response is neither easily nor accurately obtained; besides it changes sharply with attitude angles. Both of the aforementioned cases complicate the waveform design process. In this paper, an adaptive robust waveform selection method for unknown target detection in clutter is proposed. The target impulse response is considered to be unknown but belongs to a known uncertainty set. An adaptive waveform library is devised by using a signal-to-clutter-plus-noise ratio (SCNR)- based optimal waveform design method. By applying the minimax robust waveform selection method, the optimal robust waveform is selected to ensure the lowest performance bound of the unknown target detection in clutter. Results show that the adaptive waveform library outperforms the predefined linear frequency modulation (LFM) waveform library on the SCNR bound.

  15. Accelerated Singular Value-Based Ultrasound Blood Flow Clutter Filtering With Randomized Singular Value Decomposition and Randomized Spatial Downsampling.

    Science.gov (United States)

    Song, Pengfei; Trzasko, Joshua D; Manduca, Armando; Qiang, Bo; Kadirvel, Ramanathan; Kallmes, David F; Chen, Shigao

    2017-04-01

    Singular value decomposition (SVD)-based ultrasound blood flow clutter filters have recently demonstrated substantial improvement in clutter rejection for ultrafast plane wave microvessel imaging, and have become the commonly used clutter filtering method for many novel ultrafast imaging applications such as functional ultrasound and super-resolution imaging. At present, however, the computational burden of SVD remains as a major hurdle for practical implementation and clinical translation of this method. To address this challenge, in the study we present two blood flow clutter filtering methods based on randomized SVD (rSVD) and randomized spatial downsampling to accelerate SVD clutter filtering with minimal compromise to the clutter filter performance. rSVD accelerates SVD computation by approximating the k largest singular values, while random downsampling accelerates both full SVD and rSVD by decomposing the original large data matrix into small matrices that can be processed in parallel. An in vitro blood flow phantom study with the presence of heavy tissue clutter showed significantly improved computational performance using the proposed methods with minimal deterioration to the clutter filter performance (less than 3-dB reduction in blood to clutter ratio, less than 0.2-cm(2)/s(2) increase in flow mean squared error, less than 0.1-cm/s increase in the standard deviation of the vessel blood flow signal, and less than 0.3-cm/s increase in tissue clutter velocity for both full SVD and rSVD when the downsampling factor was less than 20× ). The maximum acceleration was about threefold from randomized spatial downsampling, and approximately another threefold from rSVD. An in vivo rabbit kidney perfusion study showed that rSVD provided comparable performance to full SVD in clutter rejection in vivo (maximum difference of blood to clutter ratio was less than 0.6 dB), and random downsampling provided artifact-free perfusion imaging results when combined with both

  16. 2006 Fynmeet sea clutter measurement trial: Datasets

    CSIR Research Space (South Africa)

    Herselman, PLR

    2007-09-06

    Full Text Available 3000 3200 3400 3600 -30 -25 -20 -15 -10 -5 0 5 10 15 Experiment Summary Value Radar Setup Value Type Sea Clutter Tx Frequency 9.125 GHz Date 31-Jul-2006 PRF 5 kHz Start Time 15:45:38.468 Tracking Range 2300 m Duration 183090 PRI's (36.6178 s... 15 Experiment Summary Value Radar Setup Value Type Sea Clutter Tx Frequency 9.125 GHz Date 31-Jul-2006 PRF 5 kHz Start Time 15:46:15.103 Tracking Range 2300 m Duration 212925 PRI's (42.5848 s) Range Extend 1440 m (96 gates), 15 m res...

  17. Non-local and nonlinear background suppression method controlled by multi-scale clutter metric

    Science.gov (United States)

    Gong, Jinnan; Hou, Qingyu; Zhang, Wei; Zhi, Xiyang

    2015-07-01

    To improve the detection performance for non-morphological multi-scale target in IR image containing complex cloud clutter, on basis of cloud scenario self-similarity feature, a non-local and nonlinear background suppression algorithm controlled by multi-scale clutter metric is presented. According to the classical achievements on cloud structure, self-similarity and relativity of cloud clutter on image for target detection is deeply analyzed by classical indicators firstly. Then we establish multi-scale clutter metric method based on LoG operator to describe scenes feature for controlled suppression method. After that, non-local means based on optimal strength similarity metric as non-local processing, and multi-scale median filter and on minimum gradient direction as local processing are set up. Finally linear fusing principle adopting clutter metric for local and non-local processing is put forward. Experimental results by two kinds of infrared imageries show that compared with classical and similar methods, the proposed method solves the existing problems of targets energy attenuation and suppression degradation in strongly evolving regions in previous methods. By evaluating indicators, the proposed method has a superior background suppression performance by increasing the BSF and ISCR 2 times at least.

  18. Where’s Waldo? How perceptual, cognitive, and emotional brain processes cooperate during learning to categorize and find desired objects in a cluttered scene

    Science.gov (United States)

    Chang, Hung-Cheng; Grossberg, Stephen; Cao, Yongqiang

    2014-01-01

    The Where’s Waldo problem concerns how individuals can rapidly learn to search a scene to detect, attend, recognize, and look at a valued target object in it. This article develops the ARTSCAN Search neural model to clarify how brain mechanisms across the What and Where cortical streams are coordinated to solve the Where’s Waldo problem. The What stream learns positionally-invariant object representations, whereas the Where stream controls positionally-selective spatial and action representations. The model overcomes deficiencies of these computationally complementary properties through What and Where stream interactions. Where stream processes of spatial attention and predictive eye movement control modulate What stream processes whereby multiple view- and positionally-specific object categories are learned and associatively linked to view- and positionally-invariant object categories through bottom-up and attentive top-down interactions. Gain fields control the coordinate transformations that enable spatial attention and predictive eye movements to carry out this role. What stream cognitive-emotional learning processes enable the focusing of motivated attention upon the invariant object categories of desired objects. What stream cognitive names or motivational drives can prime a view- and positionally-invariant object category of a desired target object. A volitional signal can convert these primes into top-down activations that can, in turn, prime What stream view- and positionally-specific categories. When it also receives bottom-up activation from a target, such a positionally-specific category can cause an attentional shift in the Where stream to the positional representation of the target, and an eye movement can then be elicited to foveate it. These processes describe interactions among brain regions that include visual cortex, parietal cortex, inferotemporal cortex, prefrontal cortex (PFC), amygdala, basal ganglia (BG), and superior colliculus (SC

  19. Where's Waldo? How perceptual, cognitive, and emotional brain processes cooperate during learning to categorize and find desired objects in a cluttered scene.

    Science.gov (United States)

    Chang, Hung-Cheng; Grossberg, Stephen; Cao, Yongqiang

    2014-01-01

    The Where's Waldo problem concerns how individuals can rapidly learn to search a scene to detect, attend, recognize, and look at a valued target object in it. This article develops the ARTSCAN Search neural model to clarify how brain mechanisms across the What and Where cortical streams are coordinated to solve the Where's Waldo problem. The What stream learns positionally-invariant object representations, whereas the Where stream controls positionally-selective spatial and action representations. The model overcomes deficiencies of these computationally complementary properties through What and Where stream interactions. Where stream processes of spatial attention and predictive eye movement control modulate What stream processes whereby multiple view- and positionally-specific object categories are learned and associatively linked to view- and positionally-invariant object categories through bottom-up and attentive top-down interactions. Gain fields control the coordinate transformations that enable spatial attention and predictive eye movements to carry out this role. What stream cognitive-emotional learning processes enable the focusing of motivated attention upon the invariant object categories of desired objects. What stream cognitive names or motivational drives can prime a view- and positionally-invariant object category of a desired target object. A volitional signal can convert these primes into top-down activations that can, in turn, prime What stream view- and positionally-specific categories. When it also receives bottom-up activation from a target, such a positionally-specific category can cause an attentional shift in the Where stream to the positional representation of the target, and an eye movement can then be elicited to foveate it. These processes describe interactions among brain regions that include visual cortex, parietal cortex, inferotemporal cortex, prefrontal cortex (PFC), amygdala, basal ganglia (BG), and superior colliculus (SC).

  20. Analysis of Sea Spikes in Radar Sea Clutter Data

    NARCIS (Netherlands)

    Melief, H.W.; Greidanus, H.; Genderen, P. van; Hoogeboom, P.

    2006-01-01

    Abstract—In this paper three sets of high-resolution, coherent, and polarimetric radar sea clutter data are analyzed and compared with radar sea clutter models. The nature of the data allows a thorough analysis of the power, polarization and velocity of the sea clutter. It is shown that these

  1. Analysis of Sea Spikes in Radar Sea Clutter Data

    NARCIS (Netherlands)

    Melief, H.W.; Greidanus, H.; Genderen, P. van; Hoogeboom, P.

    2006-01-01

    Abstract—In this paper three sets of high-resolution, coherent, and polarimetric radar sea clutter data are analyzed and compared with radar sea clutter models. The nature of the data allows a thorough analysis of the power, polarization and velocity of the sea clutter. It is shown that these quanti

  2. Passive localization processing for tactical unattended ground sensors

    Energy Technology Data Exchange (ETDEWEB)

    Ng, L.C.; Breitfeller, E.F.

    1995-09-01

    This report summarizes our preliminary results of a development effort to assess the potential capability of a system of unattended ground sensors to detect, classify, and localize underground sources. This report also discusses the pertinent signal processing methodologies, demonstrates the approach with computer simulations, and validates the simulations with experimental data. Specific localization methods discussed include triangulation and measurement of time difference of arrival from multiple sensor arrays.

  3. Simulation of non-stationary ground motion processes (I)

    Institute of Scientific and Technical Information of China (English)

    LIANG Jian-wen

    2005-01-01

    This paper presents a spectral representation method for simulation of non-stationary ground motion processes on the basis of Priestley's evolutionary spectral theory. Following this method, sample processes can be generated using a cosine series formula. It is shown that, these sample processes accurately reflect the prescribed characteristics of the evolutionary power spectral density function when the number of the terms in the cosine series is large enough; and the ensemble expected value and the ensemble autocorrelation function approach the corresponding target functions, respectively, as the sample size increases; and these sample processes are asymptotically normal as the number of the terms in the series tends to infinity. Finally, a few special cases of the formula are discussed, one of which is non-stationary white noise process, and other one is reduced to the formula for simulation of stationary stochastic processes.

  4. UMTRA Ground Water Project management action process document

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    A critical U.S. Department of Energy (DOE) mission is to plan, implement, and complete DOE Environmental Restoration (ER) programs at facilities that were operated by or in support of the former Atomic Energy Commission (AEC). These facilities include the 24 inactive processing sites the Uranium Mill Tailings Radiation Control Act (UMTRCA) (42 USC Section 7901 et seq.) identified as Title I sites, which had operated from the late 1940s through the 1970s. In UMTRCA, Congress acknowledged the potentially harmful health effects associated with uranium mill tailings and directed the DOE to stabilize, dispose of, and control the tailings in a safe and environmentally sound manner. The UMTRA Surface Project deals with buildings, tailings, and contaminated soils at the processing sites and any associated vicinity properties (VP). Surface remediation at the processing sites will be completed in 1997 when the Naturita, Colorado, site is scheduled to be finished. The UMTRA Ground Water Project was authorized in an amendment to the UMTRCA (42 USC Section 7922(a)), when Congress directed DOE to comply with U.S. Environmental Protection Agency (EPA) ground water standards. The UMTRA Ground Water Project addresses any contamination derived from the milling operation that is determined to be present at levels above the EPA standards.

  5. Infrared clutter measurements of marine backgrounds

    NARCIS (Netherlands)

    Schwering, Piet B.

    1991-01-01

    Observations in the infrared wavelength band between 8 and 12 μm of sea backgrounds have been recorded with a CCIR compatible imager for a large number of sea states (0 - 6). Recordings took place in coastal areas as well as on open seas. The behavior of clutter in the infrared data was analyzed in

  6. Improved Multistage Wiener Filters in Nonhomogeneous Clutter Environments

    Institute of Scientific and Technical Information of China (English)

    Bin Tang; Xue-Gang Wang; Ke-Song Chen

    2008-01-01

    A new method combining space-time preprocessing with multistage Wiener filters (STPMWF) is proposed to improve the performance of space-time adaptive processing (STAP) in nonhomogeneous clutter scenario. The new scheme only requires the data from the primary range bin, thus it can suppress discrete interferers efficiently, without calculating the inverse of covariance matrix. Comparing to the original MWF approach, the proposed scheme can be regarded as practical solutions for robust and effective STAP of nonhomogeneous radar data. The theoretical analysis shows that our STPMWF is simple in implementation and fast in convergence. The numeric results by using simulated data exhibit a good agreement with the proposed theory.

  7. Overview and Prospects of Research on Sea Clutter Property Cognition

    Directory of Open Access Journals (Sweden)

    Ding Hao

    2016-10-01

    Full Text Available Sea clutter is one of the main limiting factors influencing the target detection performance of nautical radars. The physical mechanism of sea clutter is complex with an abundance of influencing factors, and the non-Gaussian as well as non-stationarity behavior is significant. Thus, research into sea clutter property cognition is complicated and has to be systematic. Based on research that concentrates on experimental data, this paper reviews and summarizes the research developments in sea clutter property cognition. It concentrates on the properties that are of most interest for target detection algorithms: amplitude distribution, spectra, correlation, and non-stationarity and nonlinearity. The main research results are also concluded. Based on this, four aspects of problems that need further exploration are highlighted and include the following: further analysis of sea clutter influencing factors; the game problem between sea clutter precision modeling and the requirements of detection algorithms; and the property cognition between radar target and sea clutter.

  8. EMI obscuration of buried UXO by geophysical magnetic permeability, anthropogenic clutter, and by magnitude disparities

    Science.gov (United States)

    O'Neill, K.; Shubitidze, F.; Sun, K.; Shamatava, I.; Paulsen, K.

    2005-05-01

    For UWB (30 Hz - 100 kHz) electromagnetic induction (EMI) sensor discrimination of unexploded ordnance (UXO), we evaluate first the effects of significant magnetic permeability in the surrounding soil. Measured data and theoretical arguments suggest that ground effects can often be accounted for by using a simple halfspace analytical solution. Thus, when target responses are strong enough, free-space target signature shapes can still be used for discrimination if properly compensated. At the same time, even in artificially well-mixed, physically smoothed settings, local variations in soil permeability can be a significant source of signal clutter. Cases with multiple UXO"s beneath dispersed small metallic clutter are also considered as instances in which clutter may dominate. In simulations of two comparably sized UXO"s at comparable depths with a signal to clutter ratio (SCR) of ~ 20, UWB data distinguishes the two objects reliably over a ground surface measurement grid. For similar cases but with the objects at significantly different depths relative to one another, one cannot distinguish the deeper target, even with the same noise level and with UWB data. Measurements illustrate the level of EMI SCR to be expected from dispersed small metallic items collected from a firing range. For cases with a single piece of clutter and a much more massive UXO immediately below, simulations show almost complete obscuration of the UXO, in both frequency and time domains. This is not caused by signal blockage but results from different degrees of proximity to the sensor, i.e. from the consequent signal magnitude disparity.

  9. An Excel Workbook for Identifying Redox Processes in Ground Water

    Science.gov (United States)

    Jurgens, Bryant C.; McMahon, Peter B.; Chapelle, Francis H.; Eberts, Sandra M.

    2009-01-01

    The reduction/oxidation (redox) condition of ground water affects the concentration, transport, and fate of many anthropogenic and natural contaminants. The redox state of a ground-water sample is defined by the dominant type of reduction/oxidation reaction, or redox process, occurring in the sample, as inferred from water-quality data. However, because of the difficulty in defining and applying a systematic redox framework to samples from diverse hydrogeologic settings, many regional water-quality investigations do not attempt to determine the predominant redox process in ground water. Recently, McMahon and Chapelle (2008) devised a redox framework that was applied to a large number of samples from 15 principal aquifer systems in the United States to examine the effect of redox processes on water quality. This framework was expanded by Chapelle and others (in press) to use measured sulfide data to differentiate between iron(III)- and sulfate-reducing conditions. These investigations showed that a systematic approach to characterize redox conditions in ground water could be applied to datasets from diverse hydrogeologic settings using water-quality data routinely collected in regional water-quality investigations. This report describes the Microsoft Excel workbook, RedoxAssignment_McMahon&Chapelle.xls, that assigns the predominant redox process to samples using the framework created by McMahon and Chapelle (2008) and expanded by Chapelle and others (in press). Assignment of redox conditions is based on concentrations of dissolved oxygen (O2), nitrate (NO3-), manganese (Mn2+), iron (Fe2+), sulfate (SO42-), and sulfide (sum of dihydrogen sulfide [aqueous H2S], hydrogen sulfide [HS-], and sulfide [S2-]). The logical arguments for assigning the predominant redox process to each sample are performed by a program written in Microsoft Visual Basic for Applications (VBA). The program is called from buttons on the main worksheet. The number of samples that can be analyzed

  10. Main sea clutter characteristics impacting small slow moving targets detection by marine radars

    Directory of Open Access Journals (Sweden)

    O. D. Mrachkovskiy

    2013-04-01

    Full Text Available Searching of the sea clutter mathematical model is carried out in this paper. It is suitable to create based on it algorithm for small slow moving targets detection by marine radars. The compound Gaussian model for modeling sea clutter amplitude stochastic distribution is selected as a result of the sources analysis, because it was confirmed by most of researches. The discussed in the literature model based on chaos theory is choosen as perspective alternative for stochastic model; its advantage of using it for such problems solution must be definitively proved or denied. It was proposed many different distributions for high resolution sea clutter amplitude data modeling. The most frequently reported in the literature are K, Log-Normal and Weibull distributions. K distribution belonging to a compound-Gaussian model has the most significant theoretical and experimental background. This distribution choice is physically explained basing on the processes taking place when electromagnetic waves scattered from capillarity and gravity sea waves create a composed echo. Signal representing this echo is the product of two random components, called texture and speckle. Texture is the result of scattering from gravity waves, has a Gamma pdf (in case of K distribution and corresponds to slow-varying large-scale structure. Speckle is the result of scattering from isolated scatterers (capillarity waves, has a Rayleigh pdf and corresponds to rapid varying small-scale structure. So, K distribution envelope is a compound distribution consisting of a locally Rayleigh distribution speckle whose mean is modulated by a gamma distribution texture. All researches consider Rayleigh pdf for speckle. The lognormal, generalized Gaussian, inverse gamma and some other distributions were proposed for the texture. Due to literature analyses it is seen that texture distribution depends on radar range resolution, but strong dependence is not proved. Some scientists modified K

  11. Adaptive clutter rejection for ultrasound color Doppler imaging

    Science.gov (United States)

    Yoo, Yang Mo; Managuli, Ravi; Kim, Yongmin

    2005-04-01

    We have developed a new adaptive clutter rejection technique where an optimum clutter filter is dynamically selected according to the varying clutter characteristics in ultrasound color Doppler imaging. The selection criteria have been established based on the underlying clutter characteristics (i.e., the maximum instantaneous clutter velocity and the clutter power) and the properties of various candidate clutter filters (e.g., projection-initialized infinite impulse response and polynomial regression). We obtained an average improvement of 3.97 dB and 3.27 dB in flow signal-to-clutter-ratio (SCR) compared to the conventional and down-mixing methods, respectively. These preliminary results indicate that the proposed adaptive clutter rejection method could improve the sensitivity and accuracy in flow velocity estimation for ultrasound color Doppler imaging. For a 192 x 256 color Doppler image with an ensemble size of 10, the proposed method takes only 57.2 ms, which is less than the acquisition time. Thus, the proposed method could be implemented in modern ultrasound systems, while providing improved clutter rejection and more accurate velocity estimation in real time.

  12. Reduction of Surface Clutter by a Polarimetric FM-CW Radar in Underground Target Detection

    OpenAIRE

    Moriyama, Toshifumi; Yamaguchi, Yoshio; Sengoku, Masakazu; Yamada, Hiroyoshi

    1995-01-01

    This paper presents an experimental result of polarimetric detection of objects buried in a sandy ground by a synthetic aperture FM-CW radar. Emphasis is placed on the reduction of surface clutter by the polarimetric radar, which takes account of full polarimetric scattering characteristics. First, the principle of full polarimetric imaging methodology is out-lined based on the characteristic polarization states for a specific target together with a polarimetric enhancement factor which discr...

  13. Unified sensor management in unknown dynamic clutter

    Science.gov (United States)

    Mahler, Ronald; El-Fallah, Adel

    2010-04-01

    In recent years the first author has developed a unified, computationally tractable approach to multisensor-multitarget sensor management. This approach consists of closed-loop recursion of a PHD or CPHD filter with maximization of a "natural" sensor management objective function called PENT (posterior expected number of targets). In this paper we extend this approach so that it can be used in unknown, dynamic clutter backgrounds.

  14. Decreasing costs of ground data processing system development using a software product line

    Science.gov (United States)

    Chaffin, Brian

    2005-01-01

    In this paper, I describe software product lines and why a Ground Data Processing System should use one. I also describe how to develop a software product line, using examples from an imaginary Ground Data Processing System.

  15. GSTAMIDS ground-penetrating radar: data processing algorithms

    Science.gov (United States)

    Sower, Gary D.; Kilgore, Roger; Roman, Jaime R.

    2001-10-01

    The Ground Standoff Mine Detection System is now in the Engineering, Manufacturing and Development (EMD) Block 0 phase for USA CECOM. This paper describes the data processing algorithms for the GPR that are used to extract the features used for anti-tank (AT) mine detection; those used for pre-processing the data re included herein to show the enhancement of the mine signals. A key feature of the processing is the acquisition of a clean radar return signal from undisturbed soil, which is then deconvolved from each data frame waveform. This soil signal is an estimate of the system impulse response function, save for the magnitude of the reflection coefficient of the soil, which is a scalar to first order. Deconvolution thus gives the impulse response function of the buried mines, a strong enhancement over their raw measured signals. A matched filter test statistic is generated to discriminate between mines and background. Discrimination algorithms using hidden Markov model processing are describe in a paper by PD Gader et al. These processes were developed in MATLAB using dat files acquired and stored from prototype GPR systems and then refined with data form production units. The MATLAB code is then converted into C code for use on the real-time processor on GSTAMIDS. The C code modules are run as dynamic library links in MATLAB for verification. The GPR sensor suite hardware and its physical incorporation into the GSTAMIDS sensor modules are described fully in a companion paper.

  16. Surface return direction-of-arrival analysis for radar ice sounding surface clutter suppression

    DEFF Research Database (Denmark)

    Nielsen, Ulrik; Dall, Jørgen

    2015-01-01

    with coherent signal processing techniques can improve the suppression, in particular if the direction of arrival (DOA) of the clutter signal is estimated accurately. This paper deals with data-driven DOA estimation. By using P-band data from the ice shelf in Antarctica it is demonstrated that a varying...... penetration depth influences the DOA....

  17. Performance Analysis of Two CFAR Detectors in Clutter Edge Situation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper studies the performance of the GOSGO and GOSSO CFAR detectors [1] in clutter edge situation. The authors derive the analytic expressions of the false alarm probabilities in that situation, analyze their performances against clutter edge, and compare them with the OS, CA, GO and SO detectors. The results show that GOSGO possesses better performance than GO for countering clutter, but the performance of GOSSO is very unideal.

  18. Application of phase coherent transform to cloud clutter suppression

    Energy Technology Data Exchange (ETDEWEB)

    Ng, L.C. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    This paper describes a tracking algorithm using frame-to-frame correlation with frequency domain clutter suppression. Clutter suppression was mechanized via a `Phase Coherent Transform` (PCT) approach. This approach was applied to explore the feasibility of tracking a post-boost rocket from a low earth orbit satellite with real cloud background data. Simulation results show that the PCT/correlation tracking algorithm can perform satisfactorily at signal-to-clutter ratio (SCR) as low as 5 or 7 dB.

  19. Assertiveness process of Iranian nurse leaders: a grounded theory study.

    Science.gov (United States)

    Mahmoudirad, Gholamhossein; Ahmadi, Fazlollah; Vanaki, Zohreh; Hajizadeh, Ebrahim

    2009-06-01

    The purpose of this study was to explore the assertiveness process in Iranian nursing leaders. A qualitative design based on the grounded theory approach was used to collect and analyze the assertiveness experiences of 12 nurse managers working in four hospitals in Iran. Purposeful and theoretical sampling methods were employed for the data collection and selection of the participants, and semistructured interviews were held. During the data analysis, 17 categories emerged and these were categorized into three themes: "task generation", "assertiveness behavior", and "executive agents". From the participants' experiences, assertiveness theory emerged as being fundamental to the development of a schematic model describing nursing leadership behaviors. From another aspect, religious beliefs also played a fundamental role in Iranian nursing leadership assertiveness. It was concluded that bringing a change in the current support from top managers and improving self-learning are required in order to enhance the assertiveness of the nursing leaders in Iran.

  20. Ground moving target processing for tracking selected targets

    Science.gov (United States)

    Nichols, Howard; Majumder, Uttam; Owirka, Gregory; Finn, Lucas

    2016-05-01

    BAE Systems has developed a baseline real-time selected vehicle (SV) radar tracking capability that successfully tracked multiple civilian vehicles in real-world traffic conditions within challenging semi-urban clutter. This real-time tracking capability was demonstrated in laboratory setting. Recent enhancements to the baseline capability include multiple detection modes, improvements to the system-level design, and a wide-area tracking mode. The multiple detection modes support two tracking regimes; wide-area and localized selected vehicle tracking. These two tracking regimes have distinct challenges that may be suited to different trackers. Incorporation of a wide-area tracking mode provides both situational awareness and the potential for enhancing SV track initiation. Improvements to the system-level design simplify the integration of multiple detection modes and more realistic SV track initiation capabilities. Improvements are designed to contribute to a comprehensive tracking capability that exploits a continuous stare paradigm. In this paper, focus will be on the challenges, design considerations, and integration of selected vehicle tracking.

  1. A Hydrogen Containment Process For Nuclear Thermal Engine Ground Testing

    Science.gov (United States)

    Wang, Ten-See; Stewart, Eric; Canabal, Francisco

    2016-01-01

    A hydrogen containment process was proposed for ground testing of a nuclear thermal engine. The hydrogen exhaust from the engine is contained in two unit operations: an oxygen-rich burner and a tubular heat exchanger. The burner burns off the majority of the hydrogen, and the remaining hydrogen is removed in the tubular heat exchanger through the species recombination mechanism. A multi-dimensional, pressure-based multiphase computational fluid dynamics methodology was used to conceptually sizing the oxygen-rich burner, while a one-dimensional thermal analysis methodology was used to conceptually sizing the heat exchanger. Subsequently, a steady-state operation of the entire hydrogen containment process, from pressure vessel, through nozzle, diffuser, burner and heat exchanger, was simulated numerically, with the afore-mentioned computational fluid dynamics methodology. The computational results show that 99% of hydrogen reduction is achieved at the end of the burner, and the rest of the hydrogen is removed to a trivial level in the heat exchanger. The computed flammability at the exit of the heat exchanger is less than the lower flammability limit, confirming the hydrogen containment capability of the proposed process.

  2. Data processing and visualisation in the Rosetta Science Ground Segment

    Science.gov (United States)

    Geiger, Bernhard

    2016-09-01

    Rosetta is the first space mission to rendezvous with a comet. The spacecraft encountered its target 67P/Churyumov-Gerasimenko in 2014 and currently escorts the comet through a complete activity cycle during perihelion passage. The Rosetta Science Ground Segment (RSGS) is in charge of planning and coordinating the observations carried out by the scientific instruments on board the Rosetta spacecraft. We describe the data processing system implemented at the RSGS in order to support data analysis and science operations planning. The system automatically retrieves and processes telemetry data in near real-time. The generated products include spacecraft and instrument housekeeping parameters, scientific data for some instruments, and derived quantities. Based on spacecraft and comet trajectory information a series of geometric variables are calculated in order to assess the conditions for scheduling the observations of the scientific instruments and analyse the respective measurements obtained. Images acquired by the Rosetta Navigation Camera are processed and distributed in near real-time to the instrument team community. A quicklook web-page displaying the images allows the RSGS team to monitor the state of the comet and the correct acquisition and downlink of the images. Consolidated datasets are later delivered to the long-term archive.

  3. The Process of Patient's Privacy: A Grounded Theory

    Directory of Open Access Journals (Sweden)

    Heidari

    2011-12-01

    Full Text Available Introduction: Ethics, customs, and divine and human values in all scientific and non-academic issues are accepted among all human societies in different eras. The purpose of this study was to understand the experiences of nursing professionals about the patient's privacy. Methods: 21 participants were selected by theoretical sampling which was guided by emerging categories. All participants were interviewed individually. Subjects were interviewed in a private setting and transcription was done after each interview. In-depth interviews and semi-structured questions were used for data collection. Corbin and Strauss’ Ground theory methodology was applied in order to explain the process of patient's privacy. Data analysis was an ongoing process which was started during data collection. Data analysis method included a three-step coding process including open coding, axial and selective coding through repeated line by line reading of transcripts. Results: Four central categories were identified from transcripts' constant comparative analysis: weakness of system, actors with serious effort, trying to maintain privacy and tension creation. Conclusion: Familiarity with how nurses deal with patient’s privacy can improve professional development, client satisfaction and observation of their rights. Nurses with sensitivity to patient’s privacy can manage their expectations respectfully.

  4. Software for calculations of surge processes in ground conductors and grounded objects

    Directory of Open Access Journals (Sweden)

    Kuklin D.V.

    2015-03-01

    Full Text Available Software for calculations related to propagation of electromagnetic waves in high-voltage objects (transmission towers and their grounding, substation grounding has been described in the paper. Using the software the oblique thin wire simulation method proposed by Guiffaut et al. (2012 has been verified for conductive medium

  5. The neurological underpinnings of cluttering: Some initial findings.

    Science.gov (United States)

    Ward, David; Connally, Emily L; Pliatsikas, Christos; Bretherton-Furness, Jess; Watkins, Kate E

    2015-03-01

    Cluttering is a fluency disorder characterised by overly rapid or jerky speech patterns that compromise intelligibility. The neural correlates of cluttering are unknown but theoretical accounts implicate the basal ganglia and medial prefrontal cortex. Dysfunction in these brain areas would be consistent with difficulties in selection and control of speech motor programs that are characteristic of speech disfluencies in cluttering. There is a surprising lack of investigation into this disorder using modern imaging techniques. Here, we used functional MRI to investigate the neural correlates of cluttering. We scanned 17 adults who clutter and 17 normally fluent control speakers matched for age and sex. Brain activity was recorded using sparse-sampling functional MRI while participants viewed scenes and either (i) produced overt speech describing the scene or (ii) read out loud a sentence provided that described the scene. Speech was recorded and analysed off line. Differences in brain activity for each condition compared to a silent resting baseline and between conditions were analysed for each group separately (cluster-forming threshold Z>3.1, extent p30 voxels, uncorrected). In both conditions, the patterns of activation in adults who clutter and control speakers were strikingly similar, particularly at the cortical level. Direct group comparisons revealed greater activity in adults who clutter compared to control speakers in the lateral premotor cortex bilaterally and, as predicted, on the medial surface (pre-supplementary motor area). Subcortically, adults who clutter showed greater activity than control speakers in the basal ganglia. Specifically, the caudate nucleus and putamen were overactive in adults who clutter for the comparison of picture description with sentence reading. In addition, adults who clutter had reduced activity relative to control speakers in the lateral anterior cerebellum bilaterally. Eleven of the 17 adults who clutter also stuttered

  6. Wavelet based methods for improved wind profiler signal processing

    Directory of Open Access Journals (Sweden)

    V. Lehmann

    Full Text Available In this paper, we apply wavelet thresholding for removing automatically ground and intermittent clutter (airplane echoes from wind profiler radar data. Using the concept of discrete multi-resolution analysis and non-parametric estimation theory, we develop wavelet domain thresholding rules, which allow us to identify the coefficients relevant for clutter and to suppress them in order to obtain filtered reconstructions.

    Key words. Meteorology and atmospheric dynamics (instruments and techniques – Radio science (remote sensing; signal processing

  7. Effects of Video Exposure to Cluttering on Undergraduate Students' Perceptions of a Person Who Clutters

    Science.gov (United States)

    Farrell, Lindsey M.; Blanchet, Paul G.; Tillery, Kim L.

    2015-01-01

    Background: Previous research suggests a negative stereotype toward people with fluency disorders (i.e. stuttering and/or cluttering), although recent findings suggest that exposure to an actual person who stutters (e.g. a live or video presentation) leads to more positive perceptions of some personality traits. However, there is a paucity of…

  8. Clutter and rainfall discrimination by means of doppler-polarimetric measurements and vertical reflectivity profile analysis

    Directory of Open Access Journals (Sweden)

    F. Silvestro

    2005-01-01

    Full Text Available The estimation of rainfall rate and other parameters from radar scattering volume is heavily affected by the presence of intense sea and ground clutter and echoes which appears in anomalous propagation condition. To deal with these non meteorological echoes we present a new clutter removal algorithm which combines the results of previous works. The algorithm fully exploits both the Doppler and polarimetric capabilities of the radar used and the analysis of vertical reflectivity profile in order to achieve the better identification of the meteorological and non-meteorological targets. The algorithm has been applied to the C-band radar of Monte Settepani (Savona, Italy, which runs in a high-topography environment. Preliminary results are presented.

  9. Polarimetric clutter modeling: Theory and application

    Science.gov (United States)

    Kong, J. A.; Lin, F. C.; Borgeaud, M.; Yueh, H. A.; Swartz, A. A.; Lim, H. H.; Shim, R. T.; Novak, L. M.

    1988-01-01

    The two-layer anisotropic random medium model is used to investigate fully polarimetric scattering properties of earth terrain media. The polarization covariance matrices for the untilted and tilted uniaxial random medium are evaluated using the strong fluctuation theory and distorted Born approximation. In order to account for the azimuthal randomness in the growth direction of leaves in tree and grass fields, an averaging scheme over the azimuthal direction is also applied. It is found that characteristics of terrain clutter can be identified through the analysis of each element of the covariance matrix. Theoretical results are illustrated by the comparison with experimental data provided by MIT Lincoln Laboratory for tree and grass fields.

  10. An Overview of the JPSS Ground Project Algorithm Integration Process

    Science.gov (United States)

    Vicente, G. A.; Williams, R.; Dorman, T. J.; Williamson, R. C.; Shaw, F. J.; Thomas, W. M.; Hung, L.; Griffin, A.; Meade, P.; Steadley, R. S.; Cember, R. P.

    2015-12-01

    The smooth transition, implementation and operationalization of scientific software's from the National Oceanic and Atmospheric Administration (NOAA) development teams to the Join Polar Satellite System (JPSS) Ground Segment requires a variety of experiences and expertise. This task has been accomplished by a dedicated group of scientist and engineers working in close collaboration with the NOAA Satellite and Information Services (NESDIS) Center for Satellite Applications and Research (STAR) science teams for the JPSS/Suomi-NPOES Preparatory Project (S-NPP) Advanced Technology Microwave Sounder (ATMS), Cross-track Infrared Sounder (CrIS), Visible Infrared Imaging Radiometer Suite (VIIRS) and Ozone Mapping and Profiler Suite (OMPS) instruments. The presentation purpose is to describe the JPSS project process for algorithm implementation from the very early delivering stages by the science teams to the full operationalization into the Interface Processing Segment (IDPS), the processing system that provides Environmental Data Records (EDR's) to NOAA. Special focus is given to the NASA Data Products Engineering and Services (DPES) Algorithm Integration Team (AIT) functional and regression test activities. In the functional testing phase, the AIT uses one or a few specific chunks of data (granules) selected by the NOAA STAR Calibration and Validation (cal/val) Teams to demonstrate that a small change in the code performs properly and does not disrupt the rest of the algorithm chain. In the regression testing phase, the modified code is placed into to the Government Resources for Algorithm Verification, Integration, Test and Evaluation (GRAVITE) Algorithm Development Area (ADA), a simulated and smaller version of the operational IDPS. Baseline files are swapped out, not edited and the whole code package runs in one full orbit of Science Data Records (SDR's) using Calibration Look Up Tables (Cal LUT's) for the time of the orbit. The purpose of the regression test is to

  11. Increased clutter level in echocardiography due to specular reflection

    Science.gov (United States)

    Fatemi, Ali; Torp, Hans; Aakhus, Svend; Rodriguez-Molares, Alfonso

    2017-03-01

    State-of-the-art echocardiography allows to correctly diagnose most of cardiovascular diseases. An unknown source of clutter, however, hinders the visualization of the heart in some cases. We believe this clutter is caused by the ultrasound beam being partially reflected by the ribs into the elevation direction, so that structures outside the imaging plane are displayed on top of the heart image as clutter noise. We conducted in vitro experiments in a water tank using a synthetic ventricle and pig ribs. By partially blocking the probe with the ribs in the elevation direction, objects outside the imaging plane were rendered in the B-mode image, which confirms that the ribs can behave as specular reflectors. In addition, we succeeded in reproducing clutter noise using a piece of polystyrene to simulate the reflections from the lungs. This indicates that the origin of the clutter noise in echocardiograms can be reverberation coming from the lungs via specular reflection at the ribs.

  12. Distributed Fuzzy CFAR Detection for Weibull Clutter

    Science.gov (United States)

    Zaimbashi, Amir; Taban, Mohammad Reza; Nayebi, Mohammad Mehdi

    In Distributed detection systems, restricting the output of the local decision to one bit certainly implies a substantial information loss. In this paper, we consider the fuzzy detection, which uses a function called membership function for mapping the observation space of each local detector to a value between 0 and 1, indicating the degree of assurance about presence or absence of a signal. In this case, we examine the problem of distributed Maximum Likelihood (ML) and Order Statistic (OS) constant false alarm rate (CFAR) detections using fuzzy fusion rules such as “Algebraic Product” (AP), “Algebraic Sum” (AS), “Union” (Un) and “Intersection” (IS) in the fusion centre. For the Weibull clutter, the expression of the membership function based on the ML or OS CFAR processors in the local detectors is also obtained. For comparison, we consider a binary distributed detector, which uses the Maximum Likelihood and Algebraic Product (MLAP) or Order Statistic and Algebraic Product (OSAP) CFAR processors as the local detectors. In homogenous and non homogenous situations, multiple targets or clutter edge, the performances of the fuzzy and binary distributed detectors are analyzed and compared. The simulation results indicate the superior and robust performance of the distributed systems using fuzzy detection in the homogenous and non homogenous situations.

  13. Classification of radar clutter using neural networks.

    Science.gov (United States)

    Haykin, S; Deng, C

    1991-01-01

    A classifier that incorporates both preprocessing and postprocessing procedures as well as a multilayer feedforward network (based on the back-propagation algorithm) in its design to distinguish between several major classes of radar returns including weather, birds, and aircraft is described. The classifier achieves an average classification accuracy of 89% on generalization for data collected during a single scan of the radar antenna. The procedures of feature selection for neural network training, the classifier design considerations, the learning algorithm development, the implementation, and the experimental results of the neural clutter classifier, which is simulated on a Warp systolic computer, are discussed. A comparative evaluation of the multilayer neural network with a traditional Bayes classifier is presented.

  14. The Application of JDL to Suppress Sea Clutter for Shipborne HFSWR

    Directory of Open Access Journals (Sweden)

    Zhenyuan Ji

    2015-01-01

    Full Text Available This paper deals with the problem of sea clutter suppression for shipborne high frequency surface wave radar (HFSWR based on the joint domain localized (JDL adaptive processing algorithm. The performance of the novel method is compared with 2D FFT plus digital beamforming (FFT-DBF and orthogonal weight in different azimuths. The results based on simulated and real data show that the novel method provides higher detection performance than others.

  15. The Application of JDL to Suppress Sea Clutter for Shipborne HFSWR

    OpenAIRE

    2015-01-01

    This paper deals with the problem of sea clutter suppression for shipborne high frequency surface wave radar (HFSWR) based on the joint domain localized (JDL) adaptive processing algorithm. The performance of the novel method is compared with 2D FFT plus digital beamforming (FFT-DBF) and orthogonal weight in different azimuths. The results based on simulated and real data show that the novel method provides higher detection performance than others.

  16. Introduction to ground penetrating radar inverse scattering and data processing

    CERN Document Server

    Persico, Raffaele

    2014-01-01

    This book presents a comprehensive treatment of ground penetrating radar using both forward and inverse scattering mathematical techniques. Use of field data instead of laboratory data enables readers to envision real-life underground imaging; a full color insert further clarifies understanding. Along with considering the practical problem of achieving interpretable underground images, this book also features significant coverage of the problem's mathematical background. This twofold approach provides a resource that will appeal both to application oriented geologists and testing specialists,

  17. Desk Congest Desktop Congesting Software for Desktop Clutter Congestion

    Directory of Open Access Journals (Sweden)

    Solomon A. Adepoju

    2015-06-01

    Full Text Available Abstract The computer desktop environment is a working environment which can be likened unto a users desk in homes and offices. Often times the computer desktop get cluttered with files either as shortcuts used for quick links files stored temporarily to be accessed later or just being dumped there for no vivid reasons. However previous researches have shown that cluttered desktop affects users productivity and getting these files organized is a laborious task for most users. To be able to conveniently alleviate the effect clutters have on users performances and productivity there is need for third party software that will help get the desktop environment organized in a logical and efficient manner. It is to this end that desktop decongesting software is being designed and implemented to help curb clutter problems which existing tools have only partially addressed. The system is designed using Visual Basic .Net and it proves to be effective in tackling desktop congestion problem.

  18. Statistical model of clutter suppression in tissue harmonic imaging

    Science.gov (United States)

    Yan, Xiang; Hamilton, Mark F.

    2011-01-01

    A statistical model is developed for the suppression of clutter in tissue harmonic imaging (THI). Tissue heterogeneity is modeled as a random phase screen that is characterized by its correlation length and variance. With the autocorrelation function taken to be Gaussian and for small variance, statistical solutions are derived for the mean intensities at the fundamental and second-harmonic frequencies in the field of a focused sound beam that propagates through the phase screen. The statistical solutions are verified by comparison with ensemble averaging of direct numerical simulations. The model demonstrates that THI reduces the aberration clutter appearing in the focal region regardless of the depth of the aberrating layer, with suppression of the clutter most effective when the layer is close to the source. The model is also applied to the reverberation clutter that is transmitted forward along the axis of the beam. As with aberration clutter, suppression of such reverberation clutter by THI is most pronounced when the tissue heterogeneity is located close to the source. PMID:21428483

  19. A GPU-Parallelized Eigen-Based Clutter Filter Framework for Ultrasound Color Flow Imaging.

    Science.gov (United States)

    Chee, Adrian J Y; Yiu, Billy Y S; Yu, Alfred C H

    2017-01-01

    Eigen-filters with attenuation response adapted to clutter statistics in color flow imaging (CFI) have shown improved flow detection sensitivity in the presence of tissue motion. Nevertheless, its practical adoption in clinical use is not straightforward due to the high computational cost for solving eigendecompositions. Here, we provide a pedagogical description of how a real-time computing framework for eigen-based clutter filtering can be developed through a single-instruction, multiple data (SIMD) computing approach that can be implemented on a graphical processing unit (GPU). Emphasis is placed on the single-ensemble-based eigen-filtering approach (Hankel singular value decomposition), since it is algorithmically compatible with GPU-based SIMD computing. The key algebraic principles and the corresponding SIMD algorithm are explained, and annotations on how such algorithm can be rationally implemented on the GPU are presented. Real-time efficacy of our framework was experimentally investigated on a single GPU device (GTX Titan X), and the computing throughput for varying scan depths and slow-time ensemble lengths was studied. Using our eigen-processing framework, real-time video-range throughput (24 frames/s) can be attained for CFI frames with full view in azimuth direction (128 scanlines), up to a scan depth of 5 cm ( λ pixel axial spacing) for slow-time ensemble length of 16 samples. The corresponding CFI image frames, with respect to the ones derived from non-adaptive polynomial regression clutter filtering, yielded enhanced flow detection sensitivity in vivo, as demonstrated in a carotid imaging case example. These findings indicate that the GPU-enabled eigen-based clutter filtering can improve CFI flow detection performance in real time.

  20. Analysis of measured L-band airborne land clutter from the Western Cape region of South Africa

    CSIR Research Space (South Africa)

    De Witt, JJ

    2014-10-01

    Full Text Available This paper presents backscatter analysis of L-band land clutter data, measured from an airborne platform, over various terrain types encountered in the Western Cape region of South Africa. The data processing steps are described and the backscatter...

  1. Study on Clutter Model and Characteristics of Airborne Radar with Parabolic Conformal Phased Array

    Institute of Scientific and Technical Information of China (English)

    Hao Jiang; Nini Rao; Xingbo Chen; Jiabin Zhou; Chaoyang Qiu; Wen Zhai; Zhimei Hao

    2016-01-01

    The studies on clutter modeling and suppression of airborne radar with a parabolic conformal array are uncommon due to the complexity of this type of antenna array configuration. The correct understanding of clutter characteristics for airborne radar with a parabolic conformal antenna array is the prerequisite and foundation of optimal suppression of this type of clutter. This paper establishes the model of clutter echo of airborne parabolic conformal phased array radar and analyzes the structure characteristics and the distribution features of this type of clutter. The simulation results show that this type of clutter has the following characteristics: 1) The main lobe on the azimuth is seriously broadened, 2) the power spectrum presents strong heterogeneity, and 3) the freedom degrees are high. Based on the existing related clutter suppression methods, we verified the correctness of the constructed clutter model. This work has an important guidance to further study on clutter suppression methods in airborne parabolic conformal array radar.

  2. LANE MARKING DETECTION IN CLUTTERED ENVIRONMENT

    Institute of Scientific and Technical Information of China (English)

    李青; 郑南宁; 程洪

    2003-01-01

    Objective To determine the positions of marking in the presence of distracting shadows, highlight, pavement cracks, etc. Methods RGB color space is transformed into I1I2I3 color space and I2 component was used to form a new image with less effect of the clutter. Using an improved edge detection operator, an edge strength map was produced, and binarilized by adaptive thresholds. The binary image was labeled and circularity of all connected components is calculated. The Self-Organizing Mapping is adopted to extract regions which imply potential marking. Finally the position of marking was obtained by curve fitting. Results Color information was utilized fully, all thresholds were set adaptively and lane marking could be detected in challenging images with shadows, highlight or other cars. Conclusion The method based on circularity of connected components shows its outstanding robustness to lane marking detection and has a wide variety of applications in the areas of vehicle autonomous navigation and driver assistance system.

  3. A Hydrogen Containment Process for Nuclear Thermal Engine Ground testing

    Science.gov (United States)

    Wang, Ten-See; Stewart, Eric; Canabal, Francisco

    2016-01-01

    The objective of this study is to propose a new total hydrogen containment process to enable the testing required for NTP engine development. This H2 removal process comprises of two unit operations: an oxygen-rich burner and a shell-and-tube type of heat exchanger. This new process is demonstrated by simulation of the steady state operation of the engine firing at nominal conditions.

  4. Enabling UAV Navigation with Sensor and Environmental Uncertainty in Cluttered and GPS-Denied Environments.

    Science.gov (United States)

    Vanegas, Fernando; Gonzalez, Felipe

    2016-05-10

    Unmanned Aerial Vehicles (UAV) can navigate with low risk in obstacle-free environments using ground control stations that plan a series of GPS waypoints as a path to follow. This GPS waypoint navigation does however become dangerous in environments where the GPS signal is faulty or is only present in some places and when the airspace is filled with obstacles. UAV navigation then becomes challenging because the UAV uses other sensors, which in turn generate uncertainty about its localisation and motion systems, especially if the UAV is a low cost platform. Additional uncertainty affects the mission when the UAV goal location is only partially known and can only be discovered by exploring and detecting a target. This navigation problem is established in this research as a Partially-Observable Markov Decision Process (POMDP), so as to produce a policy that maps a set of motion commands to belief states and observations. The policy is calculated and updated on-line while flying with a newly-developed system for UAV Uncertainty-Based Navigation (UBNAV), to navigate in cluttered and GPS-denied environments using observations and executing motion commands instead of waypoints. Experimental results in both simulation and real flight tests show that the UAV finds a path on-line to a region where it can explore and detect a target without colliding with obstacles. UBNAV provides a new method and an enabling technology for scientists to implement and test UAV navigation missions with uncertainty where targets must be detected using on-line POMDP in real flight scenarios.

  5. Enabling UAV Navigation with Sensor and Environmental Uncertainty in Cluttered and GPS-Denied Environments

    Directory of Open Access Journals (Sweden)

    Fernando Vanegas

    2016-05-01

    Full Text Available Unmanned Aerial Vehicles (UAV can navigate with low risk in obstacle-free environments using ground control stations that plan a series of GPS waypoints as a path to follow. This GPS waypoint navigation does however become dangerous in environments where the GPS signal is faulty or is only present in some places and when the airspace is filled with obstacles. UAV navigation then becomes challenging because the UAV uses other sensors, which in turn generate uncertainty about its localisation and motion systems, especially if the UAV is a low cost platform. Additional uncertainty affects the mission when the UAV goal location is only partially known and can only be discovered by exploring and detecting a target. This navigation problem is established in this research as a Partially-Observable Markov Decision Process (POMDP, so as to produce a policy that maps a set of motion commands to belief states and observations. The policy is calculated and updated on-line while flying with a newly-developed system for UAV Uncertainty-Based Navigation (UBNAV, to navigate in cluttered and GPS-denied environments using observations and executing motion commands instead of waypoints. Experimental results in both simulation and real flight tests show that the UAV finds a path on-line to a region where it can explore and detect a target without colliding with obstacles. UBNAV provides a new method and an enabling technology for scientists to implement and test UAV navigation missions with uncertainty where targets must be detected using on-line POMDP in real flight scenarios.

  6. Improved Shape Parameter Estimation in K Clutter with Neural Networks and Deep Learning

    Directory of Open Access Journals (Sweden)

    José Raúl Fernández Machado

    2016-06-01

    Full Text Available The discrimination of the clutter interfering signal is a current problem in modern radars’ design, especially in coastal or offshore environments where the histogram of the background signal often displays heavy tails. The statistical characterization of this signal is very important for the cancellation of sea clutter, whose behavior obeys a K distribution according to the commonly accepted criterion. By using neural networks, the authors propose a new method for estimating the K shape parameter, demonstrating its superiority over the classic alternative based on the Method of Moments. Whereas both solutions have a similar performance when the entire range of possible values of the shape parameter is evaluated, the neuronal alternative achieves a much more accurate estimation for the lower Fig.s of the parameter. This is exactly the desired behavior because the best estimate occurs for the most aggressive states of sea clutter. The final design, reached by processing three different sets of computer generated K samples, used a total of nine neural networks whose contribution is synthesized in the final estimate, thus the solution can be interpreted as a deep learning approximation. The results are to be applied in the improvement of radar detectors, particularly for maintaining the operational false alarm probability close to the one conceived in the design.

  7. Work flow of signal processing data of ground penetrating radar case of rigid pavement measurements

    Energy Technology Data Exchange (ETDEWEB)

    Handayani, Gunawan [The Earth Physics and Complex Systems Research Group (Jl. Ganesa 10 Bandung Indonesia) gunawanhandayani@gmail.com (Indonesia)

    2015-04-16

    The signal processing of Ground Penetrating Radar (GPR) requires a certain work flow to obtain good results. Even though the Ground Penetrating Radar data looks similar with seismic reflection data, but the GPR data has particular signatures that the seismic reflection data does not have. This is something to do with coupling between antennae and the ground surface. Because of this, the GPR data should be treated differently from the seismic signal data processing work flow. Even though most of the processing steps still follow the same work flow of seismic reflection data such as: filtering, predictive deconvolution etc. This paper presents the work flow of GPR processing data on rigid pavement measurements. The processing steps start from raw data, de-Wow process, remove DC and continue with the standard process to get rid of noises i.e. filtering process. Some radargram particular features of rigid pavement along with pile foundations are presented.

  8. Work flow of signal processing data of ground penetrating radar case of rigid pavement measurements

    Science.gov (United States)

    Handayani, Gunawan

    2015-04-01

    The signal processing of Ground Penetrating Radar (GPR) requires a certain work flow to obtain good results. Even though the Ground Penetrating Radar data looks similar with seismic reflection data, but the GPR data has particular signatures that the seismic reflection data does not have. This is something to do with coupling between antennae and the ground surface. Because of this, the GPR data should be treated differently from the seismic signal data processing work flow. Even though most of the processing steps still follow the same work flow of seismic reflection data such as: filtering, predictive deconvolution etc. This paper presents the work flow of GPR processing data on rigid pavement measurements. The processing steps start from raw data, de-Wow process, remove DC and continue with the standard process to get rid of noises i.e. filtering process. Some radargram particular features of rigid pavement along with pile foundations are presented.

  9. Ultrawideband radar clutter measurements of forested terrain, 1991--1992

    Energy Technology Data Exchange (ETDEWEB)

    Sheen, D.M.; Severtsen, R.H.; Prince, J.M.; Davis, K.C.; Collins, H.D.

    1993-06-01

    The ultrawideband (UWB) radar clutter measurements project was conducted to provide radar clutter data for new ultrawideband radar systems which are currently under development. A particular goal of this project is to determine if conventional narrow band clutter data may be extrapolated to the UWB case. This report documents measurements conducted in 1991 and additional measurements conducted in 1992. The original project consisted of clutter measurements of forested terrain in the Olympic National Forest near Sequim, WA. The impulse radar system used a 30 kW peak impulse source with a 2 Gigasample/second digitizer to form a UHF (300--1000 MHz) ultrawideband impulse radar system. Additional measurements were conducted in parallel using a Systems Planning Corporation (SPC) step-chirp radar system. This system utilized pulse widths of 1330 nanoseconds over a bandwidth of 300--1000 MHz to obtain similar resolution to the impulse system. Due to the slow digitizer data throughput in the impulse radar system, data collection rates were significantly higher using the step-chirp system. Additional forest clutter measurements were undertaken in 1992 to increase the amount of data available, and especially to increase the amount of data from the impulse radar system.

  10. Reflectivity Model of Low Grazing Angle Radar Sea Clutter

    Institute of Scientific and Technical Information of China (English)

    FENG Sheng; CHEN Jie; CAI Tao; TU Xu-yan

    2005-01-01

    The commonly used reflectivity models of radar sea clutter are summarized. Among these models, the adjusted Barton model and the adjusted Morchin model are compared. From the analysis result, the γ-p reflectivity model is presented for low grazing angle radar sea clutter by the adjustment of the original Barton reflectivity model. The model takes into account radar frequency, grazing angle, sea condition, and polarization property. The influences of these factors on the proposed model are analyzed. The model absorbs the merits from commonly used reflectivity models for sea clutter. It introduces several researchers' opinions, and extends them. And it accounts for the reflectivity at arbitrary radar frequency from VHF to X-band, arbitrary low grazing angle, arbitrary sea condition and different polarization property. One of the main results is the proposed γ-p reflectivity model can reflect the influence of polarization on sea clutter reflectivity to some extent. The proposed γ-p reflectivity model of low-angle radar-sea clutter is validated by comparing the simulated and statistically experimental data.

  11. Ultrawideband radar clutter measurements of forested terrain, 1991--1992

    Energy Technology Data Exchange (ETDEWEB)

    Sheen, D.M.; Severtsen, R.H.; Prince, J.M.; Davis, K.C.; Collins, H.D.

    1993-06-01

    The ultrawideband (UWB) radar clutter measurements project was conducted to provide radar clutter data for new ultrawideband radar systems which are currently under development. A particular goal of this project is to determine if conventional narrow band clutter data may be extrapolated to the UWB case. This report documents measurements conducted in 1991 and additional measurements conducted in 1992. The original project consisted of clutter measurements of forested terrain in the Olympic National Forest near Sequim, WA. The impulse radar system used a 30 kW peak impulse source with a 2 Gigasample/second digitizer to form a UHF (300--1000 MHz) ultrawideband impulse radar system. Additional measurements were conducted in parallel using a Systems Planning Corporation (SPC) step-chirp radar system. This system utilized pulse widths of 1330 nanoseconds over a bandwidth of 300--1000 MHz to obtain similar resolution to the impulse system. Due to the slow digitizer data throughput in the impulse radar system, data collection rates were significantly higher using the step-chirp system. Additional forest clutter measurements were undertaken in 1992 to increase the amount of data available, and especially to increase the amount of data from the impulse radar system.

  12. Waveform design for cognitive radar: target detection in heavy clutter

    Science.gov (United States)

    Kirk, Benjamin H.; Narayanan, Ram M.; Martone, Anthony F.; Sherbondy, Kelly D.

    2016-05-01

    In many applications of radar systems, detection of targets in environments with heavy clutter and interference can be difficult. It is desired that a radar system should detect targets at a further range as well as be able to detect these targets with very few false positive or negative readings. In a cognitive radar system, there are ways that these negative effects can be mitigated and target detection can be significantly improved. An important metric to focus on for increasing target detectability is the signal-to-clutter ratio (SCR). Cognitive radar offers solutions to issues such as this with the use of a priori knowledge of targets and environments as well as real time adaptations. A feature of cognitive radar that is of interest is the ability to adapt and optimize transmitted waveforms to a given situation. A database is used to hold a priori and dynamic knowledge of the operational environment and targets to be detected, such as clutter characteristics and target radar cross-section (RCS) estimations. Assuming this knowledge is available or can be estimated in real-time, the transmitted waveform can be tailored using methods such as transmission of a spectrum corresponding to the target-to-clutter ratio (TCR). These methods provide significant improvement in distinguishing targets from clutter or interference.

  13. Public attitudes toward-and identification of-cluttering and stuttering in Norway and Puerto Rico.

    Science.gov (United States)

    St Louis, Kenneth O; Sønsterud, Hilda; Carlo, Edna J; Heitmann, Ragnhild R; Kvenseth, Helene

    2014-12-01

    The study sought to compare public attitudes toward cluttering versus stuttering in Norway and Puerto Rico and to compare respondents' identification of persons known with these fluency disorders. After reading lay definitions of cluttering and stuttering, three samples of adults from Norway and three from Puerto Rico rated their attitudes toward cluttering and/or stuttering on modified versions of the POSHA-Cl (for cluttering) and POSHA-S (for stuttering). They also identified children and adults whom they knew who either or both manifested cluttering or stuttering. Attitudes toward cluttering were essentially unaffected by rating either cluttering only or combined cluttering and stuttering on the same questionnaire in both countries. The same was also true of stuttering. Attitudes were very similar toward both disorders although slightly less positive for cluttering. Norwegian attitudes toward both disorders were generally more positive than Puerto Rican attitudes. The average respondent identified slightly more than one fluency disorder, a higher percentage for stuttering than cluttering and higher for adults than children. Cluttering-stuttering was rarely identified. Given a lay definition, this study confirmed that adults from diverse cultures hold attitudes toward cluttering that are similar to-but somewhat less positive than-their attitudes toward stuttering. It also confirmed that adults can identify cluttering among people they know, although less commonly than stuttering. Design controls in this study assured that consideration of stuttering did not affect either the attitudes or identification results for cluttering. The reader will be able to: (a) describe the effects-or lack thereof-of considerations of stuttering on attitudes toward cluttering; (b) describe differences in public identification of children and adults who either clutter or stutter; (c) describe differences between attitudes toward cluttering and stuttering in Norway and Puerto Rico

  14. Algorithm for image registration and clutter and jitter noise reduction

    Energy Technology Data Exchange (ETDEWEB)

    Brower, K.L.

    1997-02-01

    This paper presents an analytical, computational method whereby two-dimensional images of an optical source represented in terms of a set of detector array signals can be registered with respect to a reference set of detector array signals. The detector image is recovered from the detector array signals and represented over a local region by a fourth order, two-dimensional taylor series. This local detector image can then be registered by a general linear transformation with respect to a reference detector image. The detector signal in the reference frame is reconstructed by integrating this detector image over the respective reference pixel. For cases in which the general linear transformation is uncertain by up to plus-or-minus two pixels, the general linear transformation can be determined by least squares fitting the detector image to the reference detector image. This registration process reduces clutter and jitter noise to a level comparable to the electronic noise level of the detector system. Test results with and without electronic noise using an analytical test function are presented.

  15. Knowledge-based adaptive polarimetric detection in heterogeneous clutter

    Institute of Scientific and Technical Information of China (English)

    Yinan Zhao,Fengcong Li,; Xiaolin Qiao

    2014-01-01

    The detection performance and the constant false alarm rate behavior of the conventional adaptive detectors are severely degraded in heterogeneous clutter. This paper designs and analy-ses a knowledge-based (KB) adaptive polarimetric detector in het-erogeneous clutter. The proposed detection scheme is composed of a data selector using polarization knowledge and an adaptive polarization detector using training data. A polarization data se-lector based on the maximum likelihood estimation is proposed to remove outliers from the heterogeneous training data. This selector can remove outliers effectively, thus the training data is purified for estimating the clutter covariance matrix. Consequently, the performance of the adaptive detector is improved. We assess the performance of the KB adaptive polarimetric detector and the adaptive polarimetric detector without a data selector using sim-ulated data and IPIX radar data. The results show that the KB adaptive polarization detector outperforms its non-KB counter-parts.

  16. Analysis of high resolution land clutter using an X-band radar

    CSIR Research Space (South Africa)

    Melebari, A

    2015-10-01

    Full Text Available In modern radar systems with high range resolution, the statistical properties of clutter have a significant effect on the performance of the radar. Analyzing the radar returns from various clutter terrains is essential when aiming to optimize...

  17. Identification of cluttering and stuttering by the public in four countries.

    Science.gov (United States)

    St Louis, Kenneth O; Filatova, Yulia; Coşkun, Mehmet; Topbaş, Seyhun; Ozdemır, Sertan; Georgieva, Dobrinka; McCaffrey, Elise; George, Reshella D

    2010-12-01

    The investigators sought to explore and compare the identification of cluttering vs stuttering in four different country samples. After reading lay definitions of the two fluency disorders in their own language, convenience samples of 60-90 adult respondents from Turkey, Bulgaria, Russia, and the US identified 51-119 children or adults who either cluttered, stuttered, or both. They also indicated whether or not they, themselves, cluttered or stuttered. The majority of respondents in all four samples identified at least one person who cluttered, stuttered, or cluttered and stuttered. The average respondent identified one person with a fluency disorder, most likely a stutterer, less likely a clutterer, and least likely a clutterer-stutterer. Both similarities and differences characterized those identified in the three groups, e.g., the sex ratios were not the same. As with stuttering, the public apparently is aware of cluttering individuals and can identify such persons.

  18. Improved covariance matrix estimation in spectrally inhomogeneous sea clutter with application to adaptive small boat detection.

    CSIR Research Space (South Africa)

    Herselman, PL

    2008-09-01

    Full Text Available Asymptotically optimal coherent detection techniques yield sub-clutter visibility in heavy-tailed sea clutter. The adaptive linear quadratic detector inherently assumes spectral homogeneity for the reference window of the covariance matrix estimator...

  19. Seascape: ray tracing synthetic marine clutter in the midwave infrared

    Science.gov (United States)

    Constantikes, Kim T.; Osmanagich, Srcan

    1996-05-01

    Seascape is a distributed application that renders synthetic images using raytracing paradigm. It incorporates a computational model of infrared marine clutter. First principle models of water waves and light transport provide a computationally intensive clutter model implemented as a raytracer. Seascape models include sea, sky, and solar radiance, reflectance, attenuating atmospheres, constructive solid geometry targets, sensor, target, and water wave dynamics, and simple sensor image formation. Our focus is on the 3 - 5 micrometers waveband but Seascape can easily be configured for operation in the visible and longwave infrared. We have implemented an efficient parallel computation of this model on a heterogeneous array of UNIX workstations.

  20. Grounding context in face processing: color, emotion, and gender.

    Science.gov (United States)

    Gil, Sandrine; Le Bigot, Ludovic

    2015-01-01

    In recent years, researchers have become interested in the way that the affective quality of contextual information transfers to a perceived target. We therefore examined the effect of a red (vs. green, mixed red/green, and achromatic) background - known to be valenced - on the processing of stimuli that play a key role in human interactions, namely facial expressions. We also examined whether the valenced-color effect can be modulated by gender, which is also known to be valenced. Female and male adult participants performed a categorization task of facial expressions of emotion in which the faces of female and male posers expressing two ambiguous emotions (i.e., neutral and surprise) were presented against the four different colored backgrounds. Additionally, this task was completed by collecting subjective ratings for each colored background in the form of five semantic differential scales corresponding to both discrete and dimensional perspectives of emotion. We found that the red background resulted in more negative face perception than the green background, whether the poser was female or male. However, whereas this valenced-color effect was the only effect for female posers, for male posers, the effect was modulated by both the nature of the ambiguous emotion and the decoder's gender. Overall, our findings offer evidence that color and gender have a common valence-based dimension.

  1. Grounding Context in Face Processing: Color, Emotion and Gender

    Directory of Open Access Journals (Sweden)

    Sandrine eGil

    2015-03-01

    Full Text Available In recent years, researchers have become interested in the way that the affective quality of contextual information transfers to a perceived target. We therefore examined the effect of a red (versus green, mixed red/green and achromatic background–known to be valenced−on the processing of stimuli that play a key role in human interactions, namely facial expressions. We also examined whether the valenced-color effect can be modulated by gender, which is also known to be valenced. Female and male adult participants performed a categorization task of facial expressions of emotion in which the faces of female and male posers expressing two ambiguous emotions (i.e., neutral and surprise were presented against the four different colored backgrounds. Additionally, this task was completed by collecting subjective ratings for each colored background in the form of five semantic differential scales corresponding to both discrete and dimensional perspectives of emotion. We found that the red background resulted in more negative face perception than the green background, whether the poser was female or male. However, whereas this valenced-color effect was the only effect for female posers, for male posers, the effect was modulated by both the nature of the ambiguous emotion and the decoder’s gender. Overall, our findings offer evidence that color and gender have a common valence-based dimension.

  2. A Real-Time Nowcast/Forecast System for Radar Electrojet Clutter Driven by Global Assimilative Models of the Ionosphere

    Science.gov (United States)

    Carrano, C. S.; Alcala, C. M.; Liang, P.; Groves, K. M.; Donatelli, D. E.; Daniell, R. E.

    2006-12-01

    The Space-Based Radar Ionospheric Effects Simulation (SBR-IES) tool was developed to predict the degrading effects of the ionosphere on the performance of space-based radar systems. This presentation focuses on the technique used by the SBR-IES to predict radar electrojet clutter. The term electrojet clutter refers to backscatter from electron density irregularities that develop in response to unstable (two-stream) current systems in the auroral and equatorial electrojets. The two-stream instability is a dominant mechanism for the generation of electrojet clutter for radars operating in and above the VHF frequency band. The effects of these irregularities on the performance of ground- and space-based radars are discussed. The ionospheric clutter predictions are made using the approach developed for the Comprehensive E-Region Auroral Clutter (CERAC) model by SRI International and Rome Laboratory. The threshold velocity required for the generation of ionospheric irregularities by the two-stream instability is computed using nonlinear plasma wave theory. The streaming velocity, or the relative velocity between the electrons and ions, is calculated based on the ExB drift. When the streaming velocity exceeds the threshold, the clutter strength is estimated using an empirical relationship involving the radar frequency, electron density, magnetic aspect angle, and flow angle. A uniformly distributed layer of scattering irregularities is assumed. The ionospheric clutter predictions provided by the initial version of the SBR-IES tool were based on a climatological, or average, description of ionospheric conditions at the time of observation, driven by Kp, Ap, and the 10.7 cm solar flux. This approach, while having the advantage of requiring only a few geophysical input parameters to run, is limited by the use of overly simplified (smoothed) climatological models for the electric field, as well as electron, ion, and neutral densities and temperatures within the E

  3. Numerical analysis of heat exchange processes for the ground source heat pump system

    Science.gov (United States)

    Saito, H.; Muto, H.; Moritani, S.; Kohgo, Y.; Hamamoto, S.; Takemura, T.; Ohnishi, J.; Komatsu, T.

    2012-12-01

    Ground source heat pump systems (GSHP) use ground or groundwater as a heat source. They can achieve much higher coefficient of performance (COP) than conventional air source heat pump systems because the temperature of the ground is much more stable than that of the air. Heat energy in the ground is then viewed as one of the renewable energy sources. GSHP has been receiving great interests among countries in North America and Western Europe, as well as some developed countries in Asia because it can potentially reduce energy consumption and greenhouse gas emission. While GSHP can inject heat from the buildings to the ground for cooling during the summer, it can pump heat stored in the ground for heating during the winter. As some physical, chemical, and biological properties of the ground and groundwater are temperature dependent, running GSHP can eventually affect groundwater quality. The main objective of this project was to develop a model that allows predicting not only ground and groundwater temperatures but also changes in physical, chemical, and biological properties of ground and groundwater with GSHP under operations. This particular study aims at simulating heat exchange and transfer processes in the ground for a vertical-loop closed GSHP system. In the closed GSHP system, an anti-freezing solution is circulated inside the closed-loop tube, called U-tube, that is buried in the ground. Heat is then transferred to the anti-freezing solution in the U-tube by a heat exchanger. In this study we used HYDRUS to predict temperature of the anti-freezing solution, as well as that of the ground. HYDRUS allows one to simulate variably-saturated water flow and solute and heat transport in porous media numerically in two- and three-dimensional domains with great flexibility in defining boundary conditions. At first changes in anti-freezing solution temperatures measured were predicted in response to Thermal Response Test (TRT) conducted at our study site. Then, heat

  4. The Remodeling Process: A Grounded Theory Study of Perceptions of Treatment among Adult Male Incest Offenders.

    Science.gov (United States)

    Scheela, Rochelle A.

    1992-01-01

    Conducted grounded theory study to explore incest offender perceptions of treatment to generate explanatory theory of sexual abuse treatment process. Findings from theoretical sampling of 20 adult male incest offenders revealed that offenders felt remodeling process occurred as they faced discovery of their abuse and went through treatment.…

  5. Statistical Analysis of SAR Sea Clutter for Classification Purposes

    Directory of Open Access Journals (Sweden)

    Jaime Martín-de-Nicolás

    2014-09-01

    Full Text Available Statistical analysis of radar clutter has always been one of the topics, where more effort has been put in the last few decades. These studies were usually focused on finding the statistical models that better fitted the clutter distribution; however, the goal of this work is not the modeling of the clutter, but the study of the suitability of the statistical parameters to carry out a sea state classification. In order to achieve this objective and provide some relevance to this study, an important set of maritime and coastal Synthetic Aperture Radar data is considered. Due to the nature of the acquisition of data by SAR sensors, speckle noise is inherent to these data, and a specific study of how this noise affects the clutter distribution is also performed in this work. In pursuit of a sense of wholeness, a thorough study of the most suitable statistical parameters, as well as the most adequate classifier is carried out, achieving excellent results in terms of classification success rates. These concluding results confirm that a sea state classification is not only viable, but also successful using statistical parameters different from those of the best modeling distribution and applying a speckle filter, which allows a better characterization of the parameters used to distinguish between different sea states.

  6. Clutter filter design for ultrasound color flow imaging.

    Science.gov (United States)

    Bjaerum, Steinar; Torp, Hans; Kristoffersen, Kjell

    2002-02-01

    For ultrasound color flow images with high quality, it is important to suppress the clutter signals originating from stationary and slowly moving tissue sufficiently. Without sufficient clutter rejection, low velocity blood flow cannot be measured, and estimates of higher velocities will have a large bias. The small number of samples available (8 to 16) makes clutter filtering in color flow imaging a challenging problem. In this paper, we review and analyze three classes of filters: finite impulse response (FIR), infinite impulse response (IIR), and regression filters. The quality of the filters was assessed based on the frequency response, as well as on the bias and variance of a mean blood velocity estimator using an autocorrelation technique. For FIR filters, the frequency response was improved by allowing a non-linear phase response. By estimating the mean blood flow velocity from two vectors filtered in the forward and backward direction, respectively, the standard deviation was significantly lower with a minimum phase filter than with a linear phase filter. For IIR filters applied to short signals, the transient part of the output signal is important. We analyzed zero, step, and projection initialization, and found that projection initialization gave the best filters. For regression filters, polynomial basis functions provide effective clutter suppression. The best filters from each of the three classes gave comparable bias and variance of the mean blood velocity estimates. However, polynomial regression filters and projection-initialized IIR filters had a slightly better frequency response than could be obtained with FIR filters.

  7. Clutter filtering influence on blood velocity estimation using speckle tracking.

    Science.gov (United States)

    Fadnes, Solveig; Bjærum, Steinar; Torp, Hans; Lovstakken, Lasse

    2015-12-01

    Blood speckle tracking has shown potential for solving the angle-dependency limitation in color flow imaging. However, as clutter filtering is still Doppler-based, flow velocities at near-perpendicular beam-to-flow angles can be severely attenuated. It is shown that the clutter filter also alters the speckle appearance through a decrease in the lateral imaging bandwidth, leading to poorer lateral resolution and thus tracking performance. Interestingly, at perpendicular beam-to-flow angles lateral band-pass characteristics are inferred, and the resulting lateral amplitude modulation could help improve tracking estimates. Simulations and flow phantom experiments showed that substantially improved results could be achieved by utilizing time-variant clutter filters (e.g., polynomial regression filters) despite the inherent decorrelation inferred by these filters, but only for higher ensemble sizes (N > 36). We found that, compared with color flow imaging, speckle tracking could yield consistent estimates well below the clutter filter cutoff, but with a higher variance attributed to the low signalto- noise ratio inferred by filter attenuation. Overall, provided that a low f-number and high ensemble lengths (N approx. > 36) can be used, speckle tracking can consistently provide angle- independent flow velocity estimates, limited only by a lower bound on the flow velocity itself.

  8. Processing the ground vibration signal produced by debris flows: the methods of amplitude and impulses compared

    Science.gov (United States)

    Arattano, M.; Abancó, C.; Coviello, V.; Hürlimann, M.

    2014-12-01

    Ground vibration sensors have been increasingly used and tested, during the last few years, as devices to monitor debris flows and they have also been proposed as one of the more reliable devices for the design of debris flow warning systems. The need to process the output of ground vibration sensors, to diminish the amount of data to be recorded, is usually due to the reduced storing capabilities and the limited power supply, normally provided by solar panels, available in the high mountain environment. There are different methods that can be found in literature to process the ground vibration signal produced by debris flows. In this paper we will discuss the two most commonly employed: the method of impulses and the method of amplitude. These two methods of data processing are analyzed describing their origin and their use, presenting examples of applications and their main advantages and shortcomings. The two methods are then applied to process the ground vibration raw data produced by a debris flow occurred in the Rebaixader Torrent (Spanish Pyrenees) in 2012. The results of this work will provide means for decision to researchers and technicians who find themselves facing the task of designing a debris flow monitoring installation or a debris flow warning equipment based on the use of ground vibration detectors.

  9. Space-polarization Collaborative Suppression Method for Ionospheric Clutter in HFSWR

    Directory of Open Access Journals (Sweden)

    Yang Yunlong

    2016-12-01

    Full Text Available High Frequency Surface Wave Radar (HFSWR is able to receive surface target and low-flying aircraft echoes at a long-distance, but it suffers severely from ionospheric clutter. In this paper, a spacepolarization collaborative-based filter is introduced to mitigate ionospheric clutter. For parameter estimation on ionospheric clutter used for filters, a spatial parameter estimation algorithm based on compressive sensing is introduced to the DOA estimation of ionospheric clutter. In addition, a polarized parameter estimation algorithm based on statistical characteristics is proposed for ionospheric clutter in the range-Doppler spectrum. Higher estimation accuracy is achieved as a result of the range-Doppler spectrum; therefore, these two estimation algorithms enhance the performance of the space-polarization collaborative suppression method for ionospheric clutter. Experimental results of practical dual-polarized HFSWR data show the effectiveness of the two algorithms and the above mentioned filter for ionospheric clutter suppression.

  10. Dynamic EMI sensor platform for digital geophysical mapping and automated clutter rejection for CONUS and OCONUS applications

    Science.gov (United States)

    Laudato, Stephen J.; Schultz, Gregory; Keranen, Joe; Miller, Jonathan S.

    2016-05-01

    The implementation of new advanced electromagnetic induction (EMI) sensor surveys at sites containing unexploded ordnance (UXO) and explosive remnants of war (ERW) is an effective method for accurate mapping and for discriminating clutter from targets of interest. We present development and integration of a next generation advanced EMI sensor onto a cart-based sensing platform to combine the mapping capability of previous digital geophysical survey instruments with the high-resolution discrimination capability of advanced characterization arrays. The EMI sensor employs a multi-axis receiver configuration to produce data sufficient for anomaly discrimination. We discuss platform design and development, data acquisition and post-processing software development, and results from field tests demonstrating the detection and discrimination capability of the cart-based system. Platform development and design focused on navigation and EMI sensor integration onto a custom, low-noise, metal-free platform. Data acquisition is via an Android application with emphasis on ease-of-use and real-time quality control (QC) of collected data. Post-processing methods emphasize QC, inversion-based anomaly location estimation, and automated or supervised polarizability-based discrimination methods to produce a prioritized dig list. Integration of the detection, clutter rejection and QC methods into the post-processing software module reduces the time required between sensor data collection and generation of a prioritized dig list. System concept of operations (CONOPs), data collection, QC, data processing procedures, and performance against various clutter objects and targets of interest will also be discussed.

  11. The Process of Social Identity Development in Adolescent High School Choral Singers: A Grounded Theory

    Science.gov (United States)

    Parker, Elizabeth Cassidy

    2014-01-01

    The purpose of this grounded theory study was to describe the process of adolescent choral singers' social identity development within three midsized, midwestern high school mixed choirs. Forty-nine interviews were conducted with 36 different participants. Secondary data sources included memoing, observations, and interviews with the choir…

  12. Jinchuan Group Breaks Ground for a 300,000-ton Copper Deep Processing Project

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>According to Jinchang Municipal Government of Gansu,on August 21,Jinchuan Group broke ground for its 400,000-ton ionic membrane caustic soda project,300,000-ton PVC project,300,000-ton copper deep processing project,

  13. Factors Affecting Christian Parents' School Choice Decision Processes: A Grounded Theory Study

    Science.gov (United States)

    Prichard, Tami G.; Swezey, James A.

    2016-01-01

    This study identifies factors affecting the decision processes for school choice by Christian parents. Grounded theory design incorporated interview transcripts, field notes, and a reflective journal to analyze themes. Comparative analysis, including open, axial, and selective coding, was used to reduce the coded statements to five code families:…

  14. Factors Affecting Christian Parents' School Choice Decision Processes: A Grounded Theory Study

    Science.gov (United States)

    Prichard, Tami G.; Swezey, James A.

    2016-01-01

    This study identifies factors affecting the decision processes for school choice by Christian parents. Grounded theory design incorporated interview transcripts, field notes, and a reflective journal to analyze themes. Comparative analysis, including open, axial, and selective coding, was used to reduce the coded statements to five code families:…

  15. A Grounded Theory of Text Revision Processes Used by Young Adolescents Who Are Deaf

    Science.gov (United States)

    Yuknis, Christina

    2014-01-01

    This study examined the revising processes used by 8 middle school students who are deaf or hard-of-hearing as they composed essays for their English classes. Using grounded theory, interviews with students and teachers in one middle school, observations of the students engaging in essay creation, and writing samples were collected for analysis.…

  16. The Process of Social Identity Development in Adolescent High School Choral Singers: A Grounded Theory

    Science.gov (United States)

    Parker, Elizabeth Cassidy

    2014-01-01

    The purpose of this grounded theory study was to describe the process of adolescent choral singers' social identity development within three midsized, midwestern high school mixed choirs. Forty-nine interviews were conducted with 36 different participants. Secondary data sources included memoing, observations, and interviews with the choir…

  17. Computer Simulation and Optimization of the Process of Thawing of Grounds Using Microwave Energy

    Science.gov (United States)

    Nekrasov, S. A.; Volkov, V. S.

    2017-01-01

    In this article, consideration is given to a mathematical model and a numerical method to calculate and optimize the process of high-speed thawing of grounds using microwave energy. Relevant examples of calculations and an analysis of results are presented.

  18. Effects of Outdoor School Ground Lessons on Students' Science Process Skills and Scientific Curiosity

    Science.gov (United States)

    Ting, Kan Lin; Siew, Nyet Moi

    2014-01-01

    The purpose of this study was to investigate the effects of outdoor school ground lessons on Year Five students' science process skills and scientific curiosity. A quasi-experimental design was employed in this study. The participants in the study were divided into two groups, one subjected to the experimental treatment, defined as…

  19. Effects of propagation conditions on radar beam-ground interaction: impact on data quality

    Directory of Open Access Journals (Sweden)

    A. Fornasiero

    2005-01-01

    Full Text Available A large part of the research in the radar meteorology is devoted to the evaluation of the radar data quality and to the radar data processing. Even when, a set of absolute quality indexes can be produced (like as ground clutter presence, beam blockage rate, distance from radar, etc., the final product quality has to be determined as a function of the task and of all the processing steps. In this paper the emphasis lies on the estimate of the rainfall at the ground level taking extra care for the correction for ground clutter and beam blockage, that are two main problems affecting radar reflectivity data in complex orography. In this work a combined algorithm is presented that avoids and/or corrects for these two effects. To achieve this existing methods are modified and integrated with the analysis of radar signal propagation in different atmospheric conditions. The atmospheric refractivity profile is retrieved from the nearest in space and time radiosounding. This measured profile is then used to define the `dynamic map' used as a declutter base-field. Then beam blockage correction is applied to the data at the scan elevations computed from this map. Two case studies are used to illustrate the proposed algorithm. One is a summer event with anomalous propagation conditions and the other one is a winter event. The new algorithm is compared to a previous method of clutter removal based only on static maps of clear air and vertical reflectivity continuity test. The improvement in rain estimate is evaluated applying statistical analysis and using rain gauges data. The better scores are related mostly to the ``optimum" choice of the elevation maps, introduced by the more accurate description of the signal propagation. Finally, a data quality indicator is introduced as an output of this scheme. This indicator has been obtained from the general scheme, which takes into account all radar data processing steps.

  20. Detecting weather radar clutter using satellite-based nowcasting products

    DEFF Research Database (Denmark)

    Jensen, Thomas B.S.; Gill, Rashpal S.; Overgaard, Søren

    2006-01-01

    for the detecting and removal of clutter. Naturally, the improved spatio-temporal resolution of the Meteosat Second Generation sensors, coupled with its increased number of spectral bands, is expected to yield even better detection accuracies. Weather radar data from three C-band Doppler weather radars...... Application Facility' of EUMETSAT and is based on multispectral images from the SEVIRI sensor of the Meteosat-8 platform. Of special interest is the 'Precipitating Clouds' product, which uses the spectral information coupled with surface temperatures from Numerical Weather Predictions to assign probabilities...... by the resolution of the radar data. Subsequently, a supervised classifier was developed based on training data selected by a weather radar expert. Results of classification of data from several different meteorological events are shown. Cases of widespread sea clutter caused by anomalous propagation are especially...

  1. Reduction of background clutter in structured lighting systems

    Science.gov (United States)

    Carlson, Jeffrey J.; Giles, Michael K.; Padilla, Denise D.; Davidson, Jr., Patrick A.; Novick, David K.; Wilson, Christopher W.

    2010-06-22

    Methods for segmenting the reflected light of an illumination source having a characteristic wavelength from background illumination (i.e. clutter) in structured lighting systems can comprise pulsing the light source used to illuminate a scene, pulsing the light source synchronously with the opening of a shutter in an imaging device, estimating the contribution of background clutter by interpolation of images of the scene collected at multiple spectral bands not including the characteristic wavelength and subtracting the estimated background contribution from an image of the scene comprising the wavelength of the light source and, placing a polarizing filter between the imaging device and the scene, where the illumination source can be polarized in the same orientation as the polarizing filter. Apparatus for segmenting the light of an illumination source from background illumination can comprise an illuminator, an image receiver for receiving images of multiple spectral bands, a processor for calculations and interpolations, and a polarizing filter.

  2. Polarization Techniques for Mitigation of Low Grazing Angle Sea Clutter

    Science.gov (United States)

    2017-01-01

    introducing undue computational complexity or requiring restructuring of the chain. For CPIs comprising more than one pulse and at least 64 range...without introducing undue computational complexity or requiring restructuring of the chain. The computational complexity of PCL was derived, and proved...sea clutter. Tech- nical Report SAND2010-3828, Sandia National Laboratories. Reilly, J. and Dockery, G. (1990). Influence of evaporation ducts on

  3. Report on Scattering Physics of Multistatic Radar Sea Clutter

    Science.gov (United States)

    2014-05-30

    clutter & targets, and assessing detection schemes using the observations and the results of data analysis. The panel recognises the potential value ...similar (as they should be, since they are based on some of the same data), whilst the GIT model has much smaller values of reflectivity at low sea...When the power is summed over range, averaged over many surface realisations and recalculated at various grazing angles and rms sea surface wave

  4. The positive side of a negative reference: the delay between linguistic processing and common ground

    Science.gov (United States)

    Noveck, Ira; Rivera, Natalia; Jaume-Guazzini, Francisco

    2017-01-01

    Interlocutors converge on names to refer to entities. For example, a speaker might refer to a novel looking object as the jellyfish and, once identified, the listener will too. The hypothesized mechanism behind such referential precedents is a subject of debate. The common ground view claims that listeners register the object as well as the identity of the speaker who coined the label. The linguistic view claims that, once established, precedents are treated by listeners like any other linguistic unit, i.e. without needing to keep track of the speaker. To test predictions from each account, we used visual-world eyetracking, which allows observations in real time, during a standard referential communication task. Participants had to select objects based on instructions from two speakers. In the critical condition, listeners sought an object with a negative reference such as not the jellyfish. We aimed to determine the extent to which listeners rely on the linguistic input, common ground or both. We found that initial interpretations were based on linguistic processing only and that common ground considerations do emerge but only after 1000 ms. Our findings support the idea that—at least temporally—linguistic processing can be isolated from common ground.

  5. Revised ground-water monitoring compliance plan for the 300 area process trenches

    Energy Technology Data Exchange (ETDEWEB)

    Schalla, R.; Aaberg, R.L.; Bates, D.J.; Carlile, J.V.M.; Freshley, M.D.; Liikala, T.L.; Mitchell, P.J.; Olsen, K.B.; Rieger, J.T.

    1988-09-01

    This document contains ground-water monitoring plans for process-water disposal trenches located on the Hanford Site. These trenches, designated the 300 Area Process Trenches, have been used since 1973 for disposal of water that contains small quantities of both chemicals and radionuclides. The ground-water monitoring plans contained herein represent revision and expansion of an effort initiated in June 1985. At that time, a facility-specific monitoring program was implemented at the 300 Area Process Trenches as part of a regulatory compliance effort for hazardous chemicals being conducted on the Hanford Site. This monitoring program was based on the ground-water monitoring requirements for interim-status facilities, which are those facilities that do not yet have final permits, but are authorized to continue interim operations while engaged in the permitting process. The applicable monitoring requirements are described in the Resource Conservation and Recovery Act (RCRA), 40 CFR 265.90 of the federal regulations, and in WAC 173-303-400 of Washington State's regulations (Washington State Department of Ecology 1986). The program implemented for the process trenches was designed to be an alternate program, which is required instead of the standard detection program when a facility is known or suspected to have contaminated the ground water in the uppermost aquifer. The plans for the program, contained in a document prepared by the US Department of Energy (USDOE) in 1985, called for monthly sampling of 14 of the 37 existing monitoring wells at the 300 Area plus the installation and sampling of 2 new wells. 27 refs., 25 figs., 15 tabs.

  6. NASA Space Technology Draft Roadmap Area 13: Ground and Launch Systems Processing

    Science.gov (United States)

    Clements, Greg

    2011-01-01

    This slide presentation reviews the technology development roadmap for the area of ground and launch systems processing. The scope of this technology area includes: (1) Assembly, integration, and processing of the launch vehicle, spacecraft, and payload hardware (2) Supply chain management (3) Transportation of hardware to the launch site (4) Transportation to and operations at the launch pad (5) Launch processing infrastructure and its ability to support future operations (6) Range, personnel, and facility safety capabilities (7) Launch and landing weather (8) Environmental impact mitigations for ground and launch operations (9) Launch control center operations and infrastructure (10) Mission integration and planning (11) Mission training for both ground and flight crew personnel (12) Mission control center operations and infrastructure (13) Telemetry and command processing and archiving (14) Recovery operations for flight crews, flight hardware, and returned samples. This technology roadmap also identifies ground, launch and mission technologies that will: (1) Dramatically transform future space operations, with significant improvement in life-cycle costs (2) Improve the quality of life on earth, while exploring in co-existence with the environment (3) Increase reliability and mission availability using low/zero maintenance materials and systems, comprehensive capabilities to ascertain and forecast system health/configuration, data integration, and the use of advanced/expert software systems (4) Enhance methods to assess safety and mission risk posture, which would allow for timely and better decision making. Several key technologies are identified, with a couple of slides devoted to one of these technologies (i.e., corrosion detection and prevention). Development of these technologies can enhance life on earth and have a major impact on how we can access space, eventually making routine commercial space access and improve building and manufacturing, and weather

  7. Imaging spectroscopy links aspen genotype with below-ground processes at landscape scales.

    Science.gov (United States)

    Madritch, Michael D; Kingdon, Clayton C; Singh, Aditya; Mock, Karen E; Lindroth, Richard L; Townsend, Philip A

    2014-01-01

    Fine-scale biodiversity is increasingly recognized as important to ecosystem-level processes. Remote sensing technologies have great potential to estimate both biodiversity and ecosystem function over large spatial scales. Here, we demonstrate the capacity of imaging spectroscopy to discriminate among genotypes of Populus tremuloides (trembling aspen), one of the most genetically diverse and widespread forest species in North America. We combine imaging spectroscopy (AVIRIS) data with genetic, phytochemical, microbial and biogeochemical data to determine how intraspecific plant genetic variation influences below-ground processes at landscape scales. We demonstrate that both canopy chemistry and below-ground processes vary over large spatial scales (continental) according to aspen genotype. Imaging spectrometer data distinguish aspen genotypes through variation in canopy spectral signature. In addition, foliar spectral variation correlates well with variation in canopy chemistry, especially condensed tannins. Variation in aspen canopy chemistry, in turn, is correlated with variation in below-ground processes. Variation in spectra also correlates well with variation in soil traits. These findings indicate that forest tree species can create spatial mosaics of ecosystem functioning across large spatial scales and that these patterns can be quantified via remote sensing techniques. Moreover, they demonstrate the utility of using optical properties as proxies for fine-scale measurements of biodiversity over large spatial scales.

  8. Function-based design process for an intelligent ground vehicle vision system

    Science.gov (United States)

    Nagel, Robert L.; Perry, Kenneth L.; Stone, Robert B.; McAdams, Daniel A.

    2010-10-01

    An engineering design framework for an autonomous ground vehicle vision system is discussed. We present both the conceptual and physical design by following the design process, development and testing of an intelligent ground vehicle vision system constructed for the 2008 Intelligent Ground Vehicle Competition. During conceptual design, the requirements for the vision system are explored via functional and process analysis considering the flows into the vehicle and the transformations of those flows. The conceptual design phase concludes with a vision system design that is modular in both hardware and software and is based on a laser range finder and camera for visual perception. During physical design, prototypes are developed and tested independently, following the modular interfaces identified during conceptual design. Prototype models, once functional, are implemented into the final design. The final vision system design uses a ray-casting algorithm to process camera and laser range finder data and identify potential paths. The ray-casting algorithm is a single thread of the robot's multithreaded application. Other threads control motion, provide feedback, and process sensory data. Once integrated, both hardware and software testing are performed on the robot. We discuss the robot's performance and the lessons learned.

  9. Concept study of a hydrogen containment process during nuclear thermal engine ground testing

    Science.gov (United States)

    Wang, Ten-See; Stewart, Eric T.; Canabal, Francisco

    A new hydrogen containment process was proposed for ground testing of a nuclear thermal engine. It utilizes two thermophysical steps to contain the hydrogen exhaust. First, the decomposition of hydrogen through oxygen-rich combustion at higher temperature; second, the recombination of remaining hydrogen with radicals at low temperature. This is achieved with two unit operations: an oxygen-rich burner and a tubular heat exchanger. A computational fluid dynamics methodology was used to analyze the entire process on a three-dimensional domain. The computed flammability at the exit of the heat exchanger was less than the lower flammability limit, confirming the hydrogen containment capability of the proposed process.

  10. An adaptive clutter and interference suppression with a minimum residue noise power

    Science.gov (United States)

    Kwag, Young Kil

    The author presents an adaptive technique for the suppression of clutter and interference in environments where no a priori knowledge about the target or the clutter and interference statistics is available. The adaptive processor generates the average weight vector, in the sense of minimum-residue-noise power, on the basis of the injected noise-level vector in the weight control algorithm. The set of weight vectors generated in a particular range-azimuth space can be stored and switched to the same sector for the unwanted-noise rejection. The adaptation rate is significantly increased when the residue noise is removed from the combiner output. The system improvement factor in suppressing the clutter and interference is not sensitive to the strength of the input CSR (clutter suppression rate) and is largely dependent on the residue clutter and interference. Simulation results show the effectiveness of the proposed method in improving the clutter and interference rejection capability.

  11. Analysis of Space Shuttle Ground Support System Fault Detection, Isolation, and Recovery Processes and Resources

    Science.gov (United States)

    Gross, Anthony R.; Gerald-Yamasaki, Michael; Trent, Robert P.

    2009-01-01

    As part of the FDIR (Fault Detection, Isolation, and Recovery) Project for the Constellation Program, a task was designed within the context of the Constellation Program FDIR project called the Legacy Benchmarking Task to document as accurately as possible the FDIR processes and resources that were used by the Space Shuttle ground support equipment (GSE) during the Shuttle flight program. These results served as a comparison with results obtained from the new FDIR capability. The task team assessed Shuttle and EELV (Evolved Expendable Launch Vehicle) historical data for GSE-related launch delays to identify expected benefits and impact. This analysis included a study of complex fault isolation situations that required a lengthy troubleshooting process. Specifically, four elements of that system were considered: LH2 (liquid hydrogen), LO2 (liquid oxygen), hydraulic test, and ground special power.

  12. Removing interfering clutter associated with radar pulses that an airborne radar receives from a radar transponder

    Science.gov (United States)

    Ormesher, Richard C.; Axline, Robert M.

    2008-12-02

    Interfering clutter in radar pulses received by an airborne radar system from a radar transponder can be suppressed by developing a representation of the incoming echo-voltage time-series that permits the clutter associated with predetermined parts of the time-series to be estimated. These estimates can be used to estimate and suppress the clutter associated with other parts of the time-series.

  13. CTE Teachers' Perspectives on the Process of CTE and Science Content Integration: A Grounded Theory

    Science.gov (United States)

    Spindler, Matthew Kenneth

    The integration of career and technical education (CTE) and academic curricular content that capitalizes on natural and inherent connections represents a challenge for CTE professionals. The research question that was used to guide the current study was: What are CTE teachers' perspectives of and experiences with the process of CTE and science content integration? And more specifically, to generate a grounded theory which explicates the process of CTE and science content integration from the perspective of CTE teachers. The CTE teachers expressed that the process of CTE and science content integration was a process of evolutionizing. From the perspective of the CTE teachers involved integrating CTE and science content resulted in their programs of study being adapted into something different than they were before the process of integration was begun. The CTE teachers revealed that the evolutions in their programs of study and themselves were associated with three other categories within the grounded theory: (a) connecting; (b) enacting; and (c) futuring. The process of CTE and science content integration represents a deep and complex episode for CTE teachers. The process of CTE and science content integration requires connecting to others, putting ideas into action, and an orienting towards the future.

  14. FIELD GROUND TRUTHING DATA COLLECTOR – A MOBILE TOOLKIT FOR IMAGE ANALYSIS AND PROCESSING

    Directory of Open Access Journals (Sweden)

    X. Meng

    2012-07-01

    Full Text Available Field Ground Truthing Data Collector is one of the four key components of the NASA funded ICCaRS project, being developed in Southeast Michigan. The ICCaRS ground truthing toolkit entertains comprehensive functions: 1 Field functions, including determining locations through GPS, gathering and geo-referencing visual data, laying out ground control points for AEROKAT flights, measuring the flight distance and height, and entering observations of land cover (and use and health conditions of ecosystems and environments in the vicinity of the flight field; 2 Server synchronization functions, such as, downloading study-area maps, aerial photos and satellite images, uploading and synchronizing field-collected data with the distributed databases, calling the geospatial web services on the server side to conduct spatial querying, image analysis and processing, and receiving the processed results in field for near-real-time validation; and 3 Social network communication functions for direct technical assistance and pedagogical support, e.g., having video-conference calls in field with the supporting educators, scientists, and technologists, participating in Webinars, or engaging discussions with other-learning portals. This customized software package is being built on Apple iPhone/iPad and Google Maps/Earth. The technical infrastructures, data models, coupling methods between distributed geospatial data processing and field data collector tools, remote communication interfaces, coding schema, and functional flow charts will be illustrated and explained at the presentation. A pilot case study will be also demonstrated.

  15. Techniques for Clutter Suppression in the Presence of Body Movements during the Detection of Respiratory Activity through UWB Radars

    Directory of Open Access Journals (Sweden)

    Antonio Lazaro

    2014-02-01

    Full Text Available This paper focuses on the feasibility of tracking the chest wall movement of a human subject during respiration from the waveforms recorded using an impulse-radio (IR ultra-wideband radar. The paper describes the signal processing to estimate sleep apnea detection and breathing rate. Some techniques to solve several problems in these types of measurements, such as the clutter suppression, body movement and body orientation detection are described. Clutter suppression is achieved using a moving averaging filter to dynamically estimate it. The artifacts caused by body movements are removed using a threshold method before analyzing the breathing signal. The motion is detected using the time delay that maximizes the received signal after a clutter removing algorithm is applied. The periods in which the standard deviations of the time delay exceed a threshold are considered macro-movements and they are neglected. The sleep apnea intervals are detected when the breathing signal is below a threshold. The breathing rate is determined from the robust spectrum estimation based on Lomb periodogram algorithm. On the other hand the breathing signal amplitude depends on the body orientation respect to the antennas, and this could be a problem. In this case, in order to maximize the signal-to-noise ratio, multiple sensors are proposed to ensure that the backscattered signal can be detected by at least one sensor, regardless of the direction the human subject is facing. The feasibility of the system is compared with signals recorded by a microphone.

  16. An Airborne Radar Clutter Tracking Algorithm Based on Multifractal and Fuzzy C-Mean Cluster

    Institute of Scientific and Technical Information of China (English)

    Wei Zhang; Sheng-Lin Yu; Gong Zhang

    2007-01-01

    For an airborne lookdown radar, clutter power often changes dynamically about 80 dB with wide distributions as the platform moves. Therefore, clutter tracking techniques are required to guide the selection of const false alarm rate (CFAR) schemes. In this work, clutter tracking is done in image domain and an algorithm combining multifractal and fuzzy C-mean (FCM) cluster is proposed. The clutter with large dynamic distributions in power density is converted to steady distributions of multifractal exponents by the multifractal transformation with the optimum moment. Then, later, the main lobe and side lobe are tracked from the multifractal exponents by FCM clustering method.

  17. Clutter in electronic medical records: examining its performance and attentional costs using eye tracking.

    Science.gov (United States)

    Moacdieh, Nadine; Sarter, Nadine

    2015-06-01

    The objective was to use eye tracking to trace the underlying changes in attention allocation associated with the performance effects of clutter, stress, and task difficulty in visual search and noticing tasks. Clutter can degrade performance in complex domains, yet more needs to be known about the associated changes in attention allocation, particularly in the presence of stress and for different tasks. Frequently used and relatively simple eye tracking metrics do not effectively capture the various effects of clutter, which is critical for comprehensively analyzing clutter and developing targeted, real-time countermeasures. Electronic medical records (EMRs) were chosen as the application domain for this research. Clutter, stress, and task difficulty were manipulated, and physicians' performance on search and noticing tasks was recorded. Several eye tracking metrics were used to trace attention allocation throughout those tasks, and subjective data were gathered via a debriefing questionnaire. Clutter degraded performance in terms of response time and noticing accuracy. These decrements were largely accentuated by high stress and task difficulty. Eye tracking revealed the underlying attentional mechanisms, and several display-independent metrics were shown to be significant indicators of the effects of clutter. Eye tracking provides a promising means to understand in detail (offline) and prevent (in real time) major performance breakdowns due to clutter. Display designers need to be aware of the risks of clutter in EMRs and other complex displays and can use the identified eye tracking metrics to evaluate and/or adjust their display. © 2015, Human Factors and Ergonomics Society.

  18. INVESTIGATION OF PROCESS PERTAINING TO INTERACTION OF TRACTOR DRIVING WHEELS WITH GROUND SURFACE

    Directory of Open Access Journals (Sweden)

    V. V. Guskov

    2017-01-01

    Full Text Available The paper presents results of investigations on the process pertaining to interaction of a driving wheel with ground surface and describes methodology for optimization of backbone parameters. The mentioned process has some specific differences in comparison with the process of wheel rolling along hard surface. Ground surface is represented by mixture of sandy and clay particles with plant residues and it has a number of physical and mechanical properties. The main of these properties is resistance of soil against compression and displacement. Compression process determines a track depth and resistance to motion and displacement process determines wheel gripping property and its tangential traction force. While executing the investigations laws of compression and displacement proposed by Prof.V. V. Katsygin as the most adequate reflection of actual processes have been used in the paper. Motion of the driving wheel along ground surface is accompanied by its slipping. It has been determined that the maximum wheel traction force is formed not with 100% slipping as it was supposed until present but the value has been obtained at 45–60 % slipping according to soil category. The developed integral equations with due account of the aspect make it possible to calculate road hold characteristics of driving wheels of the designed wheel tractor and evaluate its traction, speed and economic characteristics. Methodology has been developed for optimization of backbone parameters of wheeled running gear in the designed tractor such as design mass and adhesion weight, width, diameter and air pressure in a tire. The proposed methodology has been introduced in designing practice of wheeled tractors at OJSC “Minsk Tractor Works”.

  19. Robowell: An automated process for monitoring ground water quality using established sampling protocols

    Science.gov (United States)

    Granato, G.E.; Smith, K.P.

    1999-01-01

    Robowell is an automated process for monitoring selected ground water quality properties and constituents by pumping a well or multilevel sampler. Robowell was developed and tested to provide a cost-effective monitoring system that meets protocols expected for manual sampling. The process uses commercially available electronics, instrumentation, and hardware, so it can be configured to monitor ground water quality using the equipment, purge protocol, and monitoring well design most appropriate for the monitoring site and the contaminants of interest. A Robowell prototype was installed on a sewage treatment plant infiltration bed that overlies a well-studied unconfined sand and gravel aquifer at the Massachusetts Military Reservation, Cape Cod, Massachusetts, during a time when two distinct plumes of constituents were released. The prototype was operated from May 10 to November 13, 1996, and quality-assurance/quality-control measurements demonstrated that the data obtained by the automated method was equivalent to data obtained by manual sampling methods using the same sampling protocols. Water level, specific conductance, pH, water temperature, dissolved oxygen, and dissolved ammonium were monitored by the prototype as the wells were purged according to U.S Geological Survey (USGS) ground water sampling protocols. Remote access to the data record, via phone modem communications, indicated the arrival of each plume over a few days and the subsequent geochemical reactions over the following weeks. Real-time availability of the monitoring record provided the information needed to initiate manual sampling efforts in response to changes in measured ground water quality, which proved the method and characterized the screened portion of the plume in detail through time. The methods and the case study described are presented to document the process for future use.

  20. Ground Motions Induced by Precipitation and Fluvial Processes: An Example from Taiwan

    Science.gov (United States)

    Yang, Chu-Fang; Chi, Wu-Cheng; Lai, Ying-Ju

    2016-04-01

    Ground motions can be induced by weather-related processes. Analyzing such signals might help quantify those natural processes. Here, we used continuous seismic, meteorological and stream data to analyze broadband ground motions during heavy precipitation events in Taiwan. We detected long period seismic signals in drainage basins during two meteorological cases: Typhoon Morakot in 2009 and East Asian rainy season in 2012. The amplitudes of the seismic waveform correlate well with the amount of the precipitation and the derivative of water level and discharge in a nearby river. We proposed that these seismic signals were induced by ground tilt induced by the loading from the increased water volume in the nearby river. Furthermore, we used the seismic data to estimate and quantify the strength of precipitation during such events. The seismically derived precipitation correlates well with the observed meteorological data. It shows that the long period seismic data may be used to monitor rainfall in real-time. Next, we will try to test our tilt hypothesis using other independent datasets.

  1. Prospects for the formation of ultracold polar ground state KCs molecules via an optical process

    CERN Document Server

    Borsalino, D; Aymar, M; Luc-Koenig, E; Dulieu, O; Bouloufa-Maafa, N

    2015-01-01

    Heteronuclear alkali-metal dimers represent the class of molecules of choice for creating samples of ultracold molecules exhibiting an intrinsic large permanent electric dipole moment. Among them, the KCs molecule, with a permanent dipole moment of 1.92 Debye still remains to be observed in ultracold conditions. Based on spectroscopic studies available in the literature completed by accurate ab initio calculations, we propose several optical coherent schemes to create ultracold bosonic and fermionic KCs molecules in their absolute rovibrational ground level, starting from a weakly bound level of their electronic ground state manifold. The processes rely on the existence of convenient electronically excited states allowing an efficient stimulated Raman adiabatic transfer of the level population.

  2. Resolved target detection in clutter using correlated, dual-band imagery

    Science.gov (United States)

    Stotts, Larry B.

    2015-10-01

    This paper develops a log-likelihood ratio test statistic for resolved target detection in dual-band imagery because the previous work indicates that most of the processing gains come from processing just two bands. Simple, closed-form equations for the closed-form probabilities of false alarm and detection are given. A computer simulation validates the theory. A constant false alarm rate version of the theory is applied to real available multiband data with quasi-resolved target sets and fixed clutter noise. The results show very reasonable performance in target detectability using three sets of correlated dual-band images. Finally, this paper shows that the resolved target detection problem depends on the weighted difference between the dual-band target contrasts. The theoretical development reaffirms that the signal-to-noise ratio or contrast-to-noise ratio is approximately the weighted difference squared, divided by the normalized total image noise variance.

  3. Computational architecture for image processing on a small unmanned ground vehicle

    Science.gov (United States)

    Ho, Sean; Nguyen, Hung

    2010-08-01

    Man-portable Unmanned Ground Vehicles (UGVs) have been fielded on the battlefield with limited computing power. This limitation constrains their use primarily to teleoperation control mode for clearing areas and bomb defusing. In order to extend their capability to include the reconnaissance and surveillance missions of dismounted soldiers, a separate processing payload is desired. This paper presents a processing architecture and the design details on the payload module that enables the PackBot to perform sophisticated, real-time image processing algorithms using data collected from its onboard imaging sensors including LADAR, IMU, visible, IR, stereo, and the Ladybug spherical cameras. The entire payload is constructed from currently available Commercial off-the-shelf (COTS) components including an Intel multi-core CPU and a Nvidia GPU. The result of this work enables a small UGV to perform computationally expensive image processing tasks that once were only feasible on a large workstation.

  4. Form control in atmospheric pressure plasma processing of ground fused silica

    Science.gov (United States)

    Li, Duo; Wang, Bo; Xin, Qiang; Jin, Huiliang; Wang, Jun; Dong, Wenxia

    2014-08-01

    Atmospheric Pressure Plasma Processing (APPP) using inductively coupled plasma has demonstrated that it can achieve comparable removal rate on the optical surface of fused silica under the atmosphere pressure and has the advantage of inducing no sub-surface damage for its non-contact and chemical etching mechanism. APPP technology is a cost effective way, compared with traditional mechanical polishing, magnetorheological finishing and ion beam figuring. Thus, due to these advantages, this technology is being tested to fabricate large aperture optics of fused silica to help shorten the polishing time in optics fabrication chain. Now our group proposes to use inductively coupled plasma processing technology to fabricate ground surface of fused silica directly after the grinding stage. In this paper, form control method and several processing parameters are investigated to evaluate the removal efficiency and the surface quality, including the robustness of removal function, velocity control mode and tool path strategy. However, because of the high heat flux of inductively coupled plasma, the removal depth with time can be non-linear and the ground surface evolvement will be affected. The heat polishing phenomenon is founded. The value of surface roughness is reduced greatly, which is very helpful to reduce the time of follow-up mechanical polishing. Finally, conformal and deterministic polishing experiments are analyzed and discussed. The form error is less 3%, before and after the APPP, when 10μm depth of uniform removal is achieved on a 60×60mm ground fused silica. Also, a basin feature is fabricated to demonstrate the figuring capability and stability. Thus, APPP is a promising technology in processing the large aperture optics.

  5. Study on Dim Target Detection and Discrimination from Sea Clutter

    Institute of Scientific and Technical Information of China (English)

    WANG Wen-guang; SUN Zuo-wei; LI Chen-ming; WANG Jun

    2013-01-01

    Dim target detection from sea clutter is one of the difficult topics in ocean remote sensing application.By aiming at the shortcoming of false alarms when using track before detect (TBD) based on dynamic programming,a new discrimination method called statistics of direction histogram (SDH) is proposed,which is based on different features of trajectories between the true target and false one.Moreover,a new series of discrimination schemes of SDH and Local Extreme Value method (LEV) are studied and applied to simulate the actually measured radar data.The results show that the given discrimination is effective to reduce false alarms during dim targets detection.

  6. A Process Model for Deployment Planning of Ground-based Air Defense System Against Asymmetric Homeland Threat

    Science.gov (United States)

    2009-01-01

    A Process Model for Deployment Planning of Ground-based Air Defense System Against Asymmetric Homeland Threat Ronald L. Cypert Scientific...units, along with coordination at the state and federal agency level, a dynamic process modeling capability was chosen to chart the myriad...COVERED 00-00-2009 to 00-00-2009 4. TITLE AND SUBTITLE A Process Model for Deployment Planning of Ground-based Air Defense System Against

  7. Research on Gaussian distribution preprocess method of infrared multispectral image background clutter

    Institute of Scientific and Technical Information of China (English)

    张伟; 武春风; 邓盼; 范宁

    2004-01-01

    This paper introduces a sliding-window mean removal high pass filter by which background clutter of infrared multispectral image is obtained. The method of selecting the optimum size of the sliding-window is based on the skewness-kurtosis test. In the end, a multivariate Gaussian distribution mathematical expression of background clutter image is given.

  8. Object Recognition in Clutter: Cortical Responses Depend on the Type of Learning

    Directory of Open Access Journals (Sweden)

    Jay eHegdé

    2012-06-01

    Full Text Available Theoretical studies suggest that the visual system uses prior knowledge of visual objects to recognize them in visual clutter, and posit that the strategies for recognizing objects in clutter may differ depending on whether or not the object was learned in clutter to begin with. We tested this hypothesis using functional magnetic resonance imaging (fMRI of human subjects. We trained subjects to recognize naturalistic, yet novel objects in strong or weak clutter. We then tested subjects’ recognition performance for both sets of objects in strong clutter. We found many brain regions that were differentially responsive to objects during object recognition depending on whether they were learned in strong or weak clutter. In particular, the responses of the left fusiform gyrus reliably reflected, on a trial-to-trial basis, subjects’ object recognition performance for objects learned in the presence of strong clutter. These results indicate that the visual system does not use a single, general-purpose mechanism to cope with clutter. Instead, there are two distinct spatial patterns of activation whose responses are attributable not to the visual context in which the objects were seen, but to the context in which the objects were learned.

  9. Coherent Surface Clutter Suppression Techniques with Topography Estimation for Multi-Phase-Center Radar Ice Sounding

    DEFF Research Database (Denmark)

    Nielsen, Ulrik; Dall, Jørgen; Kristensen, Steen Savstrup;

    2012-01-01

    Radar ice sounding enables measurement of the thickness and internal structures of the large ice sheets on Earth. Surface clutter masking the signal of interest is a major obstacle in ice sounding. Algorithms for surface clutter suppression based on multi-phase-center radars are presented...

  10. Optimal waveform-based clutter suppression algorithm for recursive synthetic aperture radar imaging systems

    Science.gov (United States)

    Zhu, Binqi; Gao, Yesheng; Wang, Kaizhi; Liu, Xingzhao

    2016-04-01

    A computational method for suppressing clutter and generating clear microwave images of targets is proposed in this paper, which combines synthetic aperture radar (SAR) principles with recursive method and waveform design theory, and it is suitable for SAR for special applications. The nonlinear recursive model is introduced into the SAR operation principle, and the cubature Kalman filter algorithm is used to estimate target and clutter responses in each azimuth position based on their previous states, which are both assumed to be Gaussian distributions. NP criteria-based optimal waveforms are designed repeatedly as the sensor flies along its azimuth path and are used as the transmitting signals. A clutter suppression filter is then designed and added to suppress the clutter response while maintaining most of the target response. Thus, with fewer disturbances from the clutter response, we can generate the SAR image with traditional azimuth matched filters. Our simulations show that the clutter suppression filter significantly reduces the clutter response, and our algorithm greatly improves the SINR of the SAR image based on different clutter suppression filter parameters. As such, this algorithm may be preferable for special target imaging when prior information on the target is available.

  11. Coherent Surface Clutter Suppression Techniques with Topography Estimation for Multi-Phase-Center Radar Ice Sounding

    DEFF Research Database (Denmark)

    Nielsen, Ulrik; Dall, Jørgen; Kristensen, Steen Savstrup

    2012-01-01

    Radar ice sounding enables measurement of the thickness and internal structures of the large ice sheets on Earth. Surface clutter masking the signal of interest is a major obstacle in ice sounding. Algorithms for surface clutter suppression based on multi-phase-center radars are presented. These ...

  12. Neural Dynamics of Feedforward and Feedback Processing in Figure-Ground Segregation

    Directory of Open Access Journals (Sweden)

    Oliver W. Layton

    2014-09-01

    Full Text Available Determining whether a region belongs to the interior or exterior of a shape (figure-ground segregation is a core competency of the primate brain, yet the underlying mechanisms are not well understood. Many models assume that figure-ground segregation occurs by assembling progressively more complex representations through feedforward connections, with feedback playing only a modulatory role. We present a dynamical model of figure-ground segregation in the primate ventral stream wherein feedback plays a crucial role in disambiguating a figure’s interior and exterior. We introduce a processing strategy whereby jitter in RF center locations and variation in RF sizes is exploited to enhance and suppress neural activity inside and outside of figures, respectively. Feedforward projections emanate from units that model cells in V4 known to respond to the curvature of boundary contours (curved contour cells, and feedback projections from units predicted to exist in IT that strategically group neurons with different RF sizes and RF center locations (teardrop cells. Neurons (convex cells that preferentially respond when centered on a figure dynamically balance feedforward (bottom-up information and feedback from higher visual areas. The activation is enhanced when an interior portion of a figure is in the RF via feedback from units that detect closure in the boundary contours of a figure. Our model produces maximal activity along the medial axis of well-known figures with and without concavities, and inside algorithmically generated shapes. Our results suggest that the dynamic balancing of feedforward signals with the specific feedback mechanisms proposed by the model is crucial for figure-ground segregation.

  13. Systematic comparisons between PRISM version 1.0.0, BAP, and CSMIP ground-motion processing

    Science.gov (United States)

    Kalkan, Erol; Stephens, Christopher

    2017-02-23

    A series of benchmark tests was run by comparing results of the Processing and Review Interface for Strong Motion data (PRISM) software version 1.0.0 to Basic Strong-Motion Accelerogram Processing Software (BAP; Converse and Brady, 1992), and to California Strong Motion Instrumentation Program (CSMIP) processing (Shakal and others, 2003, 2004). These tests were performed by using the MatLAB implementation of PRISM, which is equivalent to its public release version in Java language. Systematic comparisons were made in time and frequency domains of records processed in PRISM and BAP, and in CSMIP, by using a set of representative input motions with varying resolutions, frequency content, and amplitudes. Although the details of strong-motion records vary among the processing procedures, there are only minor differences among the waveforms for each component and within the frequency passband common to these procedures. A comprehensive statistical evaluation considering more than 1,800 ground-motion components demonstrates that differences in peak amplitudes of acceleration, velocity, and displacement time series obtained from PRISM and CSMIP processing are equal to or less than 4 percent for 99 percent of the data, and equal to or less than 2 percent for 96 percent of the data. Other statistical measures, including the Euclidian distance (L2 norm) and the windowed root mean square level of processed time series, also indicate that both processing schemes produce statistically similar products.

  14. DATA PROCESSING AND ANALYSIS TOOLS BASED ON GROUND-BASED SYNTHETIC APERTURE RADAR IMAGERY

    Directory of Open Access Journals (Sweden)

    M. Crosetto

    2017-09-01

    Full Text Available The Ground-Based SAR (GBSAR is a terrestrial remote sensing technique used to measure and monitor deformation. In this paper we describe two complementary approaches to derive deformation measurements using GBSAR data. The first approach is based on radar interferometry, while the second one exploits the GBSAR amplitude. In this paper we consider the so-called discontinuous GBSAR acquisition mode. The interferometric process is not always straightforward: it requires appropriate data processing and analysis tools. One of the main critical steps is phase unwrapping, which can critically affect the deformation measurements. In this paper we describe the procedure used at the CTTC to process and analyse discontinuous GBSAR data. In the second part of the paper we describe the approach based on GBSAR amplitude images and an image-matching method.

  15. Ground Motion Data Profile of Western Turkey with Intelligent Hybrid Processing

    Science.gov (United States)

    Korkmaz, Kasim A.; Demir, Fuat

    2016-09-01

    The recent earthquakes caused severe damages on the existing buildings. By this motivation, an important amount of research work has been conducted to determine the seismic risk of seismically active regions. For an accurate seismic risk assessment, processing of ground motions would provide an advantage. Using the current technology, it is not possible to precisely predict the future earthquakes. Therefore, most of the current seismic risk assessment methodologies are based on statistical evaluation by using recurrence and magnitude of the earthquakes hit the specified region. Because of the limited number of records on earthquakes, the quality of definitions is questionable. Fuzzy logic algorithm can be used to improve the quality of the definition. In the present study, ground motion data profile of western Turkey is defined using an intelligent hybrid processing. The approach is given in a practical way for an easier and faster calculation. Earthquake data between 1970 and 1999 from western part of Turkey have been used for training. The results are tested and validated with the earthquake data between 2000 and 2015 of the same region. Enough approximation was validated between calculated values and the earthquake data by using the intelligent hybrid processing.

  16. Ground Motion Data Profile of Western Turkey with Intelligent Hybrid Processing

    Science.gov (United States)

    Korkmaz, Kasim A.; Demir, Fuat

    2017-01-01

    The recent earthquakes caused severe damages on the existing buildings. By this motivation, an important amount of research work has been conducted to determine the seismic risk of seismically active regions. For an accurate seismic risk assessment, processing of ground motions would provide an advantage. Using the current technology, it is not possible to precisely predict the future earthquakes. Therefore, most of the current seismic risk assessment methodologies are based on statistical evaluation by using recurrence and magnitude of the earthquakes hit the specified region. Because of the limited number of records on earthquakes, the quality of definitions is questionable. Fuzzy logic algorithm can be used to improve the quality of the definition. In the present study, ground motion data profile of western Turkey is defined using an intelligent hybrid processing. The approach is given in a practical way for an easier and faster calculation. Earthquake data between 1970 and 1999 from western part of Turkey have been used for training. The results are tested and validated with the earthquake data between 2000 and 2015 of the same region. Enough approximation was validated between calculated values and the earthquake data by using the intelligent hybrid processing.

  17. Language Processing as Cue Integration: Grounding the Psychology of Language in Perception and Neurophysiology.

    Science.gov (United States)

    Martin, Andrea E

    2016-01-01

    I argue that cue integration, a psychophysiological mechanism from vision and multisensory perception, offers a computational linking hypothesis between psycholinguistic theory and neurobiological models of language. I propose that this mechanism, which incorporates probabilistic estimates of a cue's reliability, might function in language processing from the perception of a phoneme to the comprehension of a phrase structure. I briefly consider the implications of the cue integration hypothesis for an integrated theory of language that includes acquisition, production, dialogue and bilingualism, while grounding the hypothesis in canonical neural computation.

  18. Blends of ground tire rubber devulcanized by microwaves/HDPE - Part A: influence of devulcanization process

    Directory of Open Access Journals (Sweden)

    Fabiula Danielli Bastos de Sousa

    2015-06-01

    Full Text Available AbstractThe main objective of this work is the study of the influence of microwaves devulcanization of the elastomeric phase on dynamically revulcanized blends based on Ground Tire Rubber (GTR/High Density Polyethylene (HDPE. The devulcanization of the GTR was performed in a system comprised of a conventional microwave oven adapted with a motorized stirring at a constant microwaves power and at various exposure times. The influence of the devulcanization process on the final properties of the blends was evaluated in terms of mechanical, viscoelastic, thermal and rheological properties. The morphology was also studied.

  19. Ground Test of the Urine Processing Assembly for Accelerations and Transfer Functions

    Science.gov (United States)

    Houston, Janice; Almond, Deborah F. (Technical Monitor)

    2001-01-01

    This viewgraph presentation gives an overview of the ground test of the urine processing assembly for accelerations and transfer functions. Details are given on the test setup, test data, data analysis, analytical results, and microgravity assessment. The conclusions of the tests include the following: (1) the single input/multiple output method is useful if the data is acquired by tri-axial accelerometers and inputs can be considered uncorrelated; (2) tying coherence with the matrix yields higher confidence in results; (3) the WRS#2 rack ORUs need to be isolated; (4) and future work includes a plan for characterizing performance of isolation materials.

  20. Inversion for atmosphere duct parameters using real radar sea clutter

    Science.gov (United States)

    Sheng, Zheng; Fang, Han-Xian

    2012-02-01

    This paper addresses the problem of estimating the lower atmospheric refractivity (M profile) under nonstandard propagation conditions frequently encountered in low altitude maritime radar applications. The vertical structure of the refractive environment is modeled using five parameters and the horizontal structure is modeled using five parameters. The refractivity model is implemented with and without a priori constraint on the duct strength as might be derived from soundings or numerical weather-prediction models. An electromagnetic propagation model maps the refractivity structure into a replica field. Replica fields are compared with the observed clutter using a squared-error objective function. A global search for the 10 environmental parameters is performed using genetic algorithms. The inversion algorithm is implemented on the basis of S-band radar sea-clutter data from Wallops Island, Virginia (SPANDAR). Reference data are from range-dependent refractivity profiles obtained with a helicopter. The inversion is assessed (i) by comparing the propagation predicted from the radar-inferred refractivity profiles with that from the helicopter profiles, (ii) by comparing the refractivity parameters from the helicopter soundings with those estimated. This technique could provide near-real-time estimation of ducting effects.

  1. Inversion for atmosphere duct parameters using real radar sea clutter

    Institute of Scientific and Technical Information of China (English)

    Sheng Zheng; Fang Han-Xian

    2012-01-01

    This paper addresses the problem of estimating the lower atmospheric refractivity (M profile) under nonstandard propagation conditions frequently encountered in low altitude maritime radar applications.The vertical structure of the refractive environment is modeled using five parameters and the horizontal structure is modeled using five parameters.The refractivity model is implemented with and without a priori constraint on the duct strength as might be derived from soundings or numerical weather-prediction models.An electromagnetic propagation model maps the refractivity structure into a replica field.Replica fields are compared with the observed clutter using a squared-error objective function.A global search for the 10 environmental parameters is performed using genetic algorithms.The inversion algorithm is implemented on the basis of S-band radar sea-clutter data from Wallops Island,Virginia (SPANDAR).Reference data are from range-dependent refractivity profiles obtained with a helicopter. The inversion is assessed (i) by comparing the propagation predicted from the radar-inferred refractivity profiles with that from the helicopter profiles,(ii) by comparing the refractivity parameters from the helicopter soundings with those estimated.This technique could provide near-real-time estimation of ducting effects.

  2. Workstation for multispectral multitemporal simulation of targets and clutter

    Science.gov (United States)

    Noah, Paul V.; Noah, Meg A.; Schroeder, John W.; Rudzinsky, Marilyn R.; Bailey, Edward W.

    1992-09-01

    DOD has a requirement to develop and evaluate systems to detect targets against clutter backgrounds. This requires a comprehensive understanding of both target and clutter properties, such as spectral signatures, radiance distributions, edge effects, etc. Acquiring a complete database for all possible physical conditions and instrument parameters is not feasible. To supplement the measured database, Ontar, under two Phase I Small Business Innovative Research (SBIR) contracts to the Naval Surface Warfare Center, and the Naval Weapons Center has developed a workstation for generating radiance maps of complicated objects and performing integrated, multispectral, multitemporal image simulation. The system includes the capability to model targets, atmosphere, clouds, sea surface, natural and man- made terrain features. Currently, the package uses an aircraft model and a first-principle's cloud model. The software, written in FORTRAN, has a user-friendly interface and graphics capabilities. The current software operates on high end PC (80386 and 80486 machines). Results of integrated scene simulation and model validation will be presented.

  3. Wind turbine clutter mitigation in coastal UHF radar.

    Science.gov (United States)

    Yang, Jing; Pan, Chao; Wang, Caijun; Jiang, Dapeng; Wen, Biyang

    2014-01-01

    Coastal UHF radar provides a unique capability to measure the sea surface dynamic parameters and detect small moving targets, by exploiting the low energy loss of electromagnetic waves propagating along the salty and good conducting ocean surface. It could compensate the blind zone of HF surface wave radar at close range and reach further distance than microwave radars. However, its performance is susceptible to wind turbines which are usually installed on the shore. The size of a wind turbine is much larger than the wavelength of radio waves at UHF band, which results in large radar cross section. Furthermore, the rotation of blades adds time-varying Doppler frequency to the clutter and makes the suppression difficult. This paper proposes a mitigation method which is based on the specific periodicity of wind turbine clutter and performed mainly in the time-frequency domain. Field experimental data of a newly developed UHF radar are used to verify this method, and the results prove its effectiveness.

  4. Looking for shapes in two-dimensional cluttered point clouds.

    Science.gov (United States)

    Srivastava, Anuj; Jermyn, Ian H

    2009-09-01

    We study the problem of identifying shape classes in point clouds. These clouds contain sampled points along contours and are corrupted by clutter and observation noise. Taking an analysis-by-synthesis approach, we simulate high-probability configurations of sampled contours using models learned from training data to evaluate the given test data. To facilitate simulations, we develop statistical models for sources of (nuisance) variability: 1) shape variations within classes, 2) variability in sampling continuous curves, 3) pose and scale variability, 4) observation noise, and 5) points introduced by clutter. The variability in sampling closed curves into finite points is represented by positive diffeomorphisms of a unit circle. We derive probability models on these functions using their square-root forms and the Fisher-Rao metric. Using a Monte Carlo approach, we simulate configurations from a joint prior on the shape-sample space and compare them to the data using a likelihood function. Average likelihoods of simulated configurations lead to estimates of posterior probabilities of different classes and, hence, Bayesian classification.

  5. Door recognition in cluttered building interiors using imagery and lidar data

    Science.gov (United States)

    Díaz-Vilariño, L.; Martínez-Sánchez, J.; Lagüela, S.; Armesto, J.; Khoshelham, K.

    2014-06-01

    Building indoors reconstruction is an active research topic due to the importance of the wide range of applications to which they can be subjected, from architecture and furniture design, to movies and video games editing, or even crime scene investigation. Among the constructive elements defining the inside of a building, doors are important entities in applications like routing and navigation, and their automated recognition is advantageous e.g. in case of large multi-storey buildings with many office rooms. The inherent complexity of the automation of the recognition process is increased by the presence of clutter and occlusions, difficult to avoid in indoor scenes. In this work, we present a pipeline of techniques used for the reconstruction and interpretation of building interiors using information acquired in the form of point clouds and images. The methodology goes in depth with door detection and labelling as either opened, closed or furniture (false positive)

  6. Automated Planning of Science Products Based on Nadir Overflights and Alerts for Onboard and Ground Processing

    Science.gov (United States)

    Chien, Steve A.; McLaren, David A.; Rabideau, Gregg R.; Mandl, Daniel; Hengemihle, Jerry

    2013-01-01

    A set of automated planning algorithms is the current operations baseline approach for the Intelligent Payload Module (IPM) of the proposed Hyper spectral Infrared Imager (HyspIRI) mission. For this operations concept, there are only local (e.g. non-depletable) operations constraints, such as real-time downlink and onboard memory, and the forward sweeping algorithm is optimal for determining which science products should be generated onboard and on ground based on geographical overflights, science priorities, alerts, requests, and onboard and ground processing constraints. This automated planning approach was developed for the HyspIRI IPM concept. The HyspIRI IPM is proposed to use an X-band Direct Broadcast (DB) capability that would enable data to be delivered to ground stations virtually as it is acquired. However, the HyspIRI VSWIR and TIR instruments will produce approximately 1 Gbps data, while the DB capability is 15 Mbps for a approx. =60X oversubscription. In order to address this mismatch, this innovation determines which data to downlink based on both the type of surface the spacecraft is overflying, and the onboard processing of data to detect events. For example, when the spacecraft is overflying Polar Regions, it might downlink a snow/ice product. Additionally, the onboard software will search for thermal signatures indicative of a volcanic event or wild fire and downlink summary information (extent, spectra) when detected, thereby reducing data volume. The planning system described above automatically generated the IPM mission plan based on requested products, the overflight regions, and available resources.

  7. Geocenter variations derived from a combined processing of LEO- and ground-based GPS observations

    Science.gov (United States)

    Männel, Benjamin; Rothacher, Markus

    2017-08-01

    GNSS observations provided by the global tracking network of the International GNSS Service (IGS, Dow et al. in J Geod 83(3):191-198, 2009) play an important role in the realization of a unique terrestrial reference frame that is accurate enough to allow a detailed monitoring of the Earth's system. Combining these ground-based data with GPS observations tracked by high-quality dual-frequency receivers on-board low earth orbiters (LEOs) is a promising way to further improve the realization of the terrestrial reference frame and the estimation of geocenter coordinates, GPS satellite orbits and Earth rotation parameters. To assess the scope of the improvement on the geocenter coordinates, we processed a network of 53 globally distributed and stable IGS stations together with four LEOs (GRACE-A, GRACE-B, OSTM/Jason-2 and GOCE) over a time interval of 3 years (2010-2012). To ensure fully consistent solutions, the zero-difference phase observations of the ground stations and LEOs were processed in a common least-squares adjustment, estimating all the relevant parameters such as GPS and LEO orbits, station coordinates, Earth rotation parameters and geocenter motion. We present the significant impact of the individual LEO and a combination of all four LEOs on the geocenter coordinates. The formal errors are reduced by around 20% due to the inclusion of one LEO into the ground-only solution, while in a solution with four LEOs LEO-specific characteristics are significantly reduced. We compare the derived geocenter coordinates w.r.t. LAGEOS results and external solutions based on GPS and SLR data. We found good agreement in the amplitudes of all components; however, the phases in x- and z-direction do not agree well.

  8. Adaptive clutter rejection for 3D color Doppler imaging: preliminary clinical study.

    Science.gov (United States)

    Yoo, Yang Mo; Sikdar, Siddhartha; Karadayi, Kerem; Kolokythas, Orpheus; Kim, Yongmin

    2008-08-01

    In three-dimensional (3D) ultrasound color Doppler imaging (CDI), effective rejection of flash artifacts caused by tissue motion (clutter) is important for improving sensitivity in visualizing blood flow in vessels. Since clutter characteristics can vary significantly during volume acquisition, a clutter rejection technique that can adapt to the underlying clutter conditions is desirable for 3D CDI. We have previously developed an adaptive clutter rejection (ACR) method, in which an optimum filter is dynamically selected from a set of predesigned clutter filters based on the measured clutter characteristics. In this article, we evaluated the ACR method with 3D in vivo data acquired from 37 kidney transplant patients clinically indicated for a duplex ultrasound examination. We compared ACR against a conventional clutter rejection method, down-mixing (DM), using a commonly-used flow signal-to-clutter ratio (SCR) and a new metric called fractional residual clutter area (FRCA). The ACR method was more effective in removing the flash artifacts while providing higher sensitivity in detecting blood flow in the arcuate arteries and veins in the parenchyma of transplanted kidneys. ACR provided 3.4 dB improvement in SCR over the DM method (11.4 +/- 1.6 dB versus 8.0 +/- 2.0 dB, p < 0.001) and had lower average FRCA values compared with the DM method (0.006 +/- 0.003 versus 0.036 +/- 0.022, p < 0.001) for all study subjects. These results indicate that the new ACR method is useful for removing nonstationary tissue motion while improving the image quality for visualizing 3D vascular structure in 3D CDI.

  9. A positioning system with no line-of-sight restrictions for cluttered environments

    Science.gov (United States)

    Prigge, Eric A.

    Accurate sensing of vehicle location and attitude is a fundamental requirement in many mobile-robot applications, but is a very challenging problem in the cluttered and unstructured environment of the real world. Many existing indoor positioning systems are limited in workspace and robustness because they require clear lines of sight or do not provide absolute, drift-free measurements. Examples include overhead vision systems, where an unobstructed view must be maintained between robot and camera, and inertial systems, where the measurements drift over time. The research presented in this dissertation provides a new location- and attitude-sensing system designed specifically to meet the challenges of operation in a realistic, cluttered indoor environment, such as that of an office building or warehouse. The system is not limited by line-of-sight restrictions and produces drift-free measurements throughout a three-dimensional operating volume that can span a large building. Accuracy of several centimeters and a few degrees is delivered at 10 Hz, and any number of the small sensor units can be in operation, all providing estimates in a common reference frame. This positioning system is based on extremely-low-frequency magnetic fields, which have excellent characteristics for penetrating line-of-sight obstructions. Beacons located throughout the workspace create the low-level fields. A sensor unit on the mobile robot samples the local magnetic field and processes the measurements to determine its location and attitude. This research overcomes limitations in existing magnetic-based systems. The design of the signal structure, based on pseudorandom codes, enables the use of multiple, distributed L-beacons and greatly expands coverage volume. The development of real-time identification and correction methods mitigates the impact of distortions caused by materials in the environment. A novel solution algorithm combats both challenges, providing increased coverage volume

  10. Image segmentation techniques for improved processing of landmine responses in ground-penetrating radar data

    Science.gov (United States)

    Torrione, Peter A.; Collins, Leslie

    2007-04-01

    As ground penetrating radar sensor phenomenology improves, more advanced statistical processing approaches become applicable to the problem of landmine detection in GPR data. Most previous studies on landmine detection in GPR data have focused on the application of statistics and physics based prescreening algorithms, new feature extraction approaches, and improved feature classification techniques. In the typical framework, prescreening algorithms provide spatial location information of anomalous responses in down-track / cross-track coordinates, and feature extraction algorithms are then tasked with generating low-dimensional information-bearing feature sets from these spatial locations. However in time-domain GPR, a significant portion of the data collected at prescreener flagged locations may be unrelated to the true anomaly responses - e.g. ground bounce response, responses either temporally "before" or "after" the anomalous response, etc. The ability to segment the information-bearing region of the GPR image from the background of the image may thus provide improved performance for feature-based processing of anomaly responses. In this work we will explore the application of Markov random fields (MRFs) to the problem of anomaly/background segmentation in GPR data. Preliminary results suggest the potential for improved feature extraction and overall performance gains via application of image segmentation approaches prior to feature extraction.

  11. Challenges to Airborne and Orbital Radar Sounding in the Presence of Surface Clutter: Lessons Learned (so far) from the Dry Valleys of Antarctica

    Science.gov (United States)

    Holt, J. W.; Peters, M. E.; Kempf, S. D.; Morse, D. L.; Blankenship, D. D.

    2005-12-01

    radar sounding data. The first technique simulates radar data using a digital elevation model (DEM) of surface topography to predict the location and shape of surface echoes in the radar data. This is complemented by the cross-track migration of radar echoes onto the surface. These migrated echoes are superimposed on imagery in order to correlate them with potential surface sources. Using these techniques enabled us to identify a number of echoes in a 24-km segment of the Dry Valleys flight path as arising from the surface and to identify subsurface echoes under the main trunk of Taylor Glacier and possibly multiple reflectors beneath the toe of Taylor Glacier. Surface-based radar confirms the thickness of the glacier at three crossing points. In the ice-free section of the test segment no real subsurface reflectors were found, indicating that the electromagnetic properties of the ground there do not allow significant radar penetration at 60 MHz and/or no radar-significant subsurface interfaces exist. These results illustrate the importance of using complementary techniques, the usefulness of a DEM, and the limitations of single-pass radar sounding data. Advanced processing techniques utilizing radar phase information show promise for achieving better clutter removal for single-pass data. Multi-pass data that we recently collected in the Dry Valleys should allow for the development of techniques to reduce or eliminate the need for a surface elevation model.

  12. GWM-a ground-water management process for the U.S. Geological Survey modular ground-water model (MODFLOW-2000)

    Science.gov (United States)

    Ahlfeld, David P.; Barlow, Paul M.; Mulligan, Anne E.

    2005-01-01

    GWM is a Ground?Water Management Process for the U.S. Geological Survey modular three?dimensional ground?water model, MODFLOW?2000. GWM uses a response?matrix approach to solve several types of linear, nonlinear, and mixed?binary linear ground?water management formulations. Each management formulation consists of a set of decision variables, an objective function, and a set of constraints. Three types of decision variables are supported by GWM: flow?rate decision variables, which are withdrawal or injection rates at well sites; external decision variables, which are sources or sinks of water that are external to the flow model and do not directly affect the state variables of the simulated ground?water system (heads, streamflows, and so forth); and binary variables, which have values of 0 or 1 and are used to define the status of flow?rate or external decision variables. Flow?rate decision variables can represent wells that extend over one or more model cells and be active during one or more model stress periods; external variables also can be active during one or more stress periods. A single objective function is supported by GWM, which can be specified to either minimize or maximize the weighted sum of the three types of decision variables. Four types of constraints can be specified in a GWM formulation: upper and lower bounds on the flow?rate and external decision variables; linear summations of the three types of decision variables; hydraulic?head based constraints, including drawdowns, head differences, and head gradients; and streamflow and streamflow?depletion constraints. The Response Matrix Solution (RMS) Package of GWM uses the Ground?Water Flow Process of MODFLOW to calculate the change in head at each constraint location that results from a perturbation of a flow?rate variable; these changes are used to calculate the response coefficients. For linear management formulations, the resulting matrix of response coefficients is then combined with other

  13. Influence of post harvest processing conditions on yield and quality of ground turmeric (Curcuma longa L.

    Directory of Open Access Journals (Sweden)

    Bambirra Maria Lúcia A.

    2002-01-01

    Full Text Available Studies were carried out to evaluate the influence of post harvest processing conditions on yield and quality of ground turmeric. Rhizomes were peeled, cooked (autoclave or immersion in water or alkaline media, sliced, dehydrated, ground, sieved, packaged in polyethylene bags and stored for 60 days at room temperature. Yields ranged from 9.84 to 14.51 g of powder/100 g of rhizome with moisture varying from 8.84 to 9.86 g/100 g. Peel removal caused 30% mass loss but the powder obtained had higher intensity of yellow and red. Cooking caused a reduction in dehydration time and provided a powder with lower moisture content, higher levels of curcuminoid pigments and higher Hunter CIE L*, a* and b* values. Cooking by immersion provided higher quality powder compared to autoclave. Use of alkaline media resulted in a product with lower curcuminoid content, and higher intensity of yellow. There was no change in pigment and colour characteristics during storage.

  14. A biophysical process based approach for estimating net primary production using satellite and ground observations

    Science.gov (United States)

    Choudhury, Bhaskar J.

    An approach is presented for calculating interannual variation of net primary production (C) of terrestrial plant communities at regional scale using satellite and ground measurements. C has been calculated as the difference of gross photosynthesis (A g) and respiration (R), recognizing that different biophysical factors exert major control on these two processes. A g has been expressed as the product of radiation use efficiency for gross photosynthesis by an unstressed canopy and intercepted photosynthetically active radiation, which is then adjusted for stresses due to soil water shortage and temperature away from optimum. R has been calculated as the sum of growth and maintenance components (respectively, R g and R m. The R m has been determined from nitrogen content of plant tissue per unit ground area, while R g has been obtained as a fraction of the difference of A g and R m. Model parameters have not been determined by matching the calculated fluxes against observations at any location. Results are presented for cultivated and temperate deciduous forest areas over North America for five consecutive years (1986-1990) and compared with observations.

  15. Climatological Processing and Product Development for the TRMM Ground Validation Program

    Science.gov (United States)

    Marks, D. A.; Kulie, M. S.; Robinson, M.; Silberstein, D. S.; Wolff, D. B.; Ferrier, B. S.; Amitai, E.; Fisher, B.; Wang, J.; Augustine, D.; Thiele, O.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The Tropical Rainfall Measuring Mission (TRMM) satellite was successfully launched in November 1997.The main purpose of TRMM is to sample tropical rainfall using the first active spaceborne precipitation radar. To validate TRMM satellite observations, a comprehensive Ground Validation (GV) Program has been implemented. The primary goal of TRMM GV is to provide basic validation of satellite-derived precipitation measurements over monthly climatologies for the following primary sites: Melbourne, FL; Houston, TX; Darwin, Australia- and Kwajalein Atoll, RMI As part of the TRMM GV effort, research analysts at NASA Goddard Space Flight Center (GSFC) generate standardized rainfall products using quality-controlled ground-based radar data from the four primary GV sites. This presentation will provide an overview of TRMM GV climatological processing and product generation. A description of the data flow between the primary GV sites, NASA GSFC, and the TRMM Science and Data Information System (TSDIS) will be presented. The radar quality control algorithm, which features eight adjustable height and reflectivity parameters, and its effect on monthly rainfall maps, will be described. The methodology used to create monthly, gauge-adjusted rainfall products for each primary site will also be summarized. The standardized monthly rainfall products are developed in discrete, modular steps with distinct intermediate products. A summary of recently reprocessed official GV rainfall products available for TRMM science users will be presented. Updated basic standardized product results involving monthly accumulation, Z-R relationship, and gauge statistics for each primary GV site will also be displayed.

  16. An analysis of the trend in ground-level ozone using non-homogeneous poisson processes

    Science.gov (United States)

    Shively, Thomas S.

    This paper provides a method for measuring the long-term trend in the frequency with which ground-level ozone present in the ambient air exceeds the U.S. Environmental Protection Agency's National Ambient Air Quality Standard (NAAQS) for ozone. A major weakness of previous studies that estimate the long-term trend in the very high values of ozone, and therefore the long-term trend in the probability of satisfying the NAAQS for ozone, is their failure to account for the confounding effects of meterological conditions on ozone levels. Meteorological variables such as temperature, wind speed, and frontal passage play an important role in the formation of ground-level ozone. A non-homogenous Poisson process is used to account for the relationship between very high values of ozone and meteorological conditions. This model provides an estimate of the trend in the ozone values after allowing for the effects of meteorological conditions. Therefore, this model provides a means to measure the effectiveness of pollution control programs after accounting for the effects of changing weather conditions. When our approach is applied to data collected at two sites in Houston, TX, we find evidence of a gradual long-term downward trend in the frequency of high values of ozone. The empirical results indicate how possibly misleading results can be obtained if the analysis does not account for changing weather conditions.

  17. Observer detection and discrimination performance as a function of clutter: a signal detection approach

    Science.gov (United States)

    Bora, Archana; Aggarwal, Tarun; Lakshminarayanan, Vasudevan

    2011-11-01

    In this paper we investigate the use of signal detection theory (SDT) in predicting target detection and discrimination in disorganized clutter. Two normal observers performed monocular visual search experiments at 25 cm, in the dark. They detected Gabor gratings on an achromatic background cluttered with 2000 or 500 random dots. The targets were displayed at pseudorandom locations from 0-20° and 20-47°, by method of constant stimuli. A contrast-based detection and orientation-based discrimination task was completed in a yes/no or 2-alternative-forced-choice (2AFC) task. The hit rate, false alarm rate, detectability, criterion and bias were analysed. The psychometric function indicated low detection and discrimination thresholds in low clutter that increased in high clutter. Increased clutter showed high hit rates and a false alarm rate that increased with low detectability and liberal criterion. In the detection task, low clutter showed high hit rates and low false alarm rates in the central field. Therefore, SDT proves useful to predict observer performance in visual scenes with disorganized clutter.

  18. Bayesian Contrast Measures and Clutter Distribution Determinants of Human Target Detection.

    Science.gov (United States)

    Novak, Ana; Armstrong, Nicholas; Caelli, Terry; Blair, Iain

    2017-03-01

    Human target detection is known to be dependent on a number of components: one, basic electro-optics including image contrast, the target size, pixel resolution, and contrast sensitivity; two, target shape, image type and features, types of clutter; and three, context and task requirements. Here, we consider a Bayesian approach to investigating how these components contribute to target detection. To this end, we develop and compare three different formulations for contrast: mean contrast, perceptual contrast, and a Bayesian-based histogram contrast statistic. Results on past detection data show how the latter contrast measure correlates well with human performance factoring out all other dimensions. As for clutter, our findings show that with large targets, there are effectively no clutter effects. Furthermore, clutter does not have a major effect on detection when it is not contiguous with the target even when it is smaller. However, except for large targets, when the target is contiguous with the clutter, detection clearly decreases as a function of the similarity of target and clutter features-creating type of "clutter camouflage". This Bayesian formulation uses priors based on the contrast histogram statistics derived from all the images, the image context, and implies that human observers have adapted their criteria to fit with the image set, context, and task.

  19. Weak Target Detection within the Nonhomogeneous Ionospheric Clutter Background of HFSWR Based on STAP

    Directory of Open Access Journals (Sweden)

    Xin Zhang

    2013-01-01

    Full Text Available High Frequency Surface Wave Radar (HFSWR can perform the functions of ocean environment monitoring, target detection, and target tracking over the horizon. However, its system's performance is always limited by the severe ionospheric clutter environment, especially by the nonhomogeneous component. The nonhomogeneous ionospheric clutter generally can cover a few Doppler shift units and a few angle units. Consequently, weak targets masked by the nonhomogeneous ionospheric clutter are difficult to be detected. In this paper, a novel algorithm based on angle-Doppler joint eigenvector which considers the angle-Doppler map of radar echoes is adopted to analyze the characteristics of the nonhomogeneous ionospheric clutter. Given the measured data set, we first investigate the correlation between the signal of interest (SOI and the nonhomogeneous ionospheric clutter and then the correlation between the nonhomogeneous ionospheric clutters in different two ranges. Finally, a new strategy of training data selection is proposed to improve the joint domain localised (JDL algorithm. Simulation results show that the improved-JDL algorithm is effective and the performance of weak target detection within nonhomogeneous ionospheric clutter is improved.

  20. Modern Approaches to the Computation of the Probability of Target Detection in Cluttered Environments

    Science.gov (United States)

    Meitzler, Thomas J.

    The field of computer vision interacts with fields such as psychology, vision research, machine vision, psychophysics, mathematics, physics, and computer science. The focus of this thesis is new algorithms and methods for the computation of the probability of detection (Pd) of a target in a cluttered scene. The scene can be either a natural visual scene such as one sees with the naked eye (visual), or, a scene displayed on a monitor with the help of infrared sensors. The relative clutter and the temperature difference between the target and background (DeltaT) are defined and then used to calculate a relative signal -to-clutter ratio (SCR) from which the Pd is calculated for a target in a cluttered scene. It is shown how this definition can include many previous definitions of clutter and (DeltaT). Next, fuzzy and neural -fuzzy techniques are used to calculate the Pd and it is shown how these methods can give results that have a good correlation with experiment. The experimental design for actually measuring the Pd of a target by observers is described. Finally, wavelets are applied to the calculation of clutter and it is shown how this new definition of clutter based on wavelets can be used to compute the Pd of a target.

  1. Study of clutter origin in in-vivo epi-optoacoustic imaging of human forearms

    Science.gov (United States)

    Preisser, Stefan; Held, Gerrit; Akarçay, Hidayet G.; Jaeger, Michael; Frenz, Martin

    2016-09-01

    Epi-optoacoustic (OA) imaging offers flexible clinical diagnostics of the human body when the irradiation optic is attached to or directly integrated into the acoustic probe. Epi-OA images, however, encounter clutter that deteriorates contrast and significantly limits imaging depth. This study elaborates clutter origin in clinical epi-optoacoustic imaging using a linear array probe for scanning the human forearm. We demonstrate that the clutter strength strongly varies with the imaging location but stays stable over time, indicating that clutter is caused by anatomical structures. OA transients which are generated by strong optical absorbers located at the irradiation spot were identified to be the main source of clutter. These transients obscure deep in-plane OA signals when detected by the transducer either directly or after being acoustically scattered in the imaging plane. In addition, OA transients generated in the skin below the probe result in acoustic reverberations, which cause problems in image interpretation and limit imaging depth. Understanding clutter origin allows a better interpretation of clinical OA imaging, helps to design clutter compensation techniques and raises the prospect of contrast optimization via the design of the irradiation geometry.

  2. Negotiating the equivocality of palliative care: a grounded theory of team communicative processes in inpatient medicine.

    Science.gov (United States)

    Ledford, Christy J W; Canzona, Mollie Rose; Cafferty, Lauren A; Kalish, Virginia B

    2016-01-01

    In the majority of U.S. hospitals, inpatient medicine teams make palliative care decisions in the absence of a formalized palliative system. Using a grounded theory approach, interviews with inpatient team members were systematically analyzed to uncover how participants conceptualize palliative care and how they regard the communicative structures that underlie its delivery. During analysis, Weick's model of organizing emerged as a framework that fit the data. The 39 participant inpatient team members discussed palliative care as primarily a communicative process. Themes describing the meaning of palliative care emerged around the concepts of receiver of care, timeline of care, and location of care. The emerging model included four stages in the communicative processes of inpatient palliative care: (a) interpret the need, (b) initiate the conversation, (c) integrate the processes, and (d) identify what works. In contrast to stable, focused palliative care teams or hospice care teams, which have prescribed patient populations and processes, the inpatient medicine team faces the equivocality of providing palliative care within a broader practice. This research offers a four-phase model to show how these inpatient teams communicate within this context. Implications for the provision of palliative care are discussed.

  3. Surface roughening of ground fused silica processed by atmospheric inductively coupled plasma

    Energy Technology Data Exchange (ETDEWEB)

    Xin, Qiang; Li, Na; Wang, Jun; Wang, Bo, E-mail: bradywang@hit.edu.cn; Li, Guo; Ding, Fei; Jin, Huiliang

    2015-06-30

    Highlights: • The morphology evolution of ground fused silica, processed by atmospheric plasma, was investigated experimentally. • The roughness development results from opening and coalescing of the plasma-etched cracks. • The shapes of grain-like etched pits are the results of the adjacent cracks coalescing with one another. • The descent of the pits density is due to some smaller etched pits that are swallowed up by larger pits. • Leading role in surface smoothing is laterally etching away the side walls of the intersecting pits. - Abstract: Subsurface damage (SSD) is a defect that is inevitably induced during mechanical processes, such as grinding and polishing. This defect dramatically reduces the mechanical strength and the laser damage thresholds of optical elements. Compared with traditional mechanical machining, atmospheric pressure plasma processing (APPP) is a relatively novel technology that induces almost no SSD during the processing of silica-based optical materials. In this paper, a form of APPP, inductively coupled plasma (ICP), is used to process fused silica substrates with fluorocarbon precursor under atmospheric pressure. The surface morphology evolution of ICP-processed substrates was observed and characterized by confocal laser scanning microscope (CLSM), field emission scanning electron microscope (SEM), and atomic force microscopy (AFM). The results show that the roughness evolves with the etching depth, and the roughness evolution is a single-peaked curve. This curve results from the opening and the coalescing of surface cracks and fractures. The coalescence procedure of these microstructures was simulated with two common etched pits on a polished fused silica surface. Understanding the roughness evolution of plasma-processed surface might be helpful in optimizing the optical fabrication chain that contains APPP.

  4. Decision-making processes for the self-management of persistent pain: a grounded theory study.

    Science.gov (United States)

    Fenwick, Clare; Chaboyer, Wendy; St John, Winsome

    2012-08-01

    Persistent pain negatively impacts upon the individual suffering this condition. Almost all care related to persistent pain is self-managed. Decision-making is a critical skill of the self-manager and without these skills it would be improbable that effective self-management would emerge. However, current theories regarding decision-making and self-management have not adequately accounted for the many difficulties faced by individuals enduring persistent pain and the consequences of these experiences for the decision-maker. This grounded theory study revealed that individuals will transform into three distinct types of decision-makers using three different styles of decision-making in response to the many and varied problems related to the experience of persistent pain. These findings will provide nurses with valuable information to better equip individuals with persistent pain through the decision-making processes necessary for successful self-management.

  5. Intermittency of the turbulent processes in the Earth's magnetosphere detected from the ground-based measurements

    Science.gov (United States)

    Stepanova, Marina; Foppiano, Alberto; Ovalle, Elias; Antonova, Elizavieta; Troshichev, Oleg

    2008-11-01

    Turbulent processes in the Earth's magnetosphere are reflected in the dynamical behavior of the geomagnetic indices and other parameters determined from ground based observations. Intermittent properties of one minute Polar Cap (PC) index and auroral radio wave absorption are studied using 1995-2000 data sets. It was found that the probability distribution functions (PDFs) of both PC-index and absorption fluctuations display a strong non-Gaussian shape. This indicates that they are not characterized by a global time self-similarity but rather exhibit intermittency, as previously reported for solar wind velocity and auroral electrojet index values. In the case of the auroral absorption it was also found that intermittency strongly depends on the magnetic local time, being largest in the nighttime sector. This shows that the acceleration of precipitating particles is intermittent, especially near the substorm eye, where the level of turbulence increases. Application of the Local Intermittency Measure (LIM) technique confirms the aforementioned results to a better precision.

  6. A model and regularization scheme for ultrasonic beamforming clutter reduction.

    Science.gov (United States)

    Byram, Brett; Dei, Kazuyuki; Tierney, Jaime; Dumont, Douglas

    2015-11-01

    Acoustic clutter produced by off-axis and multipath scattering is known to cause image degradation, and in some cases these sources may be the prime determinants of in vivo image quality. We have previously shown some success addressing these sources of image degradation by modeling the aperture domain signal from different sources of clutter, and then decomposing aperture domain data using the modeled sources. Our previous model had some shortcomings including model mismatch and failure to recover B-Mode speckle statistics. These shortcomings are addressed here by developing a better model and by using a general regularization approach appropriate for the model and data. We present results with L1 (lasso), L2 (ridge), and L1/L2 combined (elastic-net) regularization methods. We call our new method aperture domain model image reconstruction (ADMIRE). Our results demonstrate that ADMIRE with L1 regularization, or weighted toward L1 in the case of elastic-net regularization, have improved image quality. L1 by itself works well, but additional improvements are seen with elastic-net regularization over the pure L1 constraint. On in vivo example cases, L1 regularization showed mean contrast improvements of 4.6 and 6.8 dB on fundamental and harmonic images, respectively. Elastic net regularization (α = 0.9) showed mean contrast improvements of 17.8 dB on fundamental images and 11.8 dB on harmonic images. We also demonstrate that in uncluttered Field II simulations the decluttering algorithm produces the same contrast, contrast-tonoise ratio, and speckle SNR as normal B-mode imaging, demonstrating that ADMIRE preserves typical image features.

  7. Comparison of the accident process, radioactivity release and ground contamination between Chernobyl and Fukushima-1.

    Science.gov (United States)

    Imanaka, Tetsuji; Hayashi, Gohei; Endo, Satoru

    2015-12-01

    In this report, we have reviewed the basic features of the accident processes and radioactivity releases that occurred in the Chernobyl accident (1986) and in the Fukushima-1 accident (2011). The Chernobyl accident was a power-surge accident that was caused by a failure of control of a fission chain reaction, which instantaneously destroyed the reactor and building, whereas the Fukushima-1 accident was a loss-of-coolant accident in which the reactor cores of three units were melted by decay heat after losing the electricity supply. Although the quantity of radioactive noble gases released from Fukushima-1 exceeded the amount released from Chernobyl, the size of land area severely contaminated by (137)Cesium ((137)Cs) was 10 times smaller around Fukushima-1 compared with around Chernobyl. The differences in the accident process are reflected in the composition of the discharged radioactivity as well as in the composition of the ground contamination. Volatile radionuclides (such as (132)Te-(132)I, (131)I, (134)Cs and (137)Cs) contributed to the gamma-ray exposure from the ground contamination around Fukishima-1, whereas a greater variety of radionuclides contributed significantly around Chernobyl. When radioactivity deposition occurred, the radiation exposure rate near Chernobyl is estimated to have been 770 μGy h(-1) per initial (137)Cs deposition of 1000 kBq m(-2), whereas it was 100 μGy h(-1) around Fukushima-1. Estimates of the cumulative exposure for 30 years are 970 and 570 mGy per initial deposition of 1000 kBq m(-2) for Chernobyl and Fukusima-1, respectively. Of these exposures, 49 and 98% were contributed by radiocesiums ((134)Cs + (137)Cs) around Chernobyl and Fukushima-1, respectively. © The Author 2015. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

  8. Comparison of the accident process, radioactivity release and ground contamination between Chernobyl and Fukushima-1

    Science.gov (United States)

    Imanaka, Tetsuji; Hayashi, Gohei; Endo, Satoru

    2015-01-01

    In this report, we have reviewed the basic features of the accident processes and radioactivity releases that occurred in the Chernobyl accident (1986) and in the Fukushima-1 accident (2011). The Chernobyl accident was a power-surge accident that was caused by a failure of control of a fission chain reaction, which instantaneously destroyed the reactor and building, whereas the Fukushima-1 accident was a loss-of-coolant accident in which the reactor cores of three units were melted by decay heat after losing the electricity supply. Although the quantity of radioactive noble gases released from Fukushima-1 exceeded the amount released from Chernobyl, the size of land area severely contaminated by 137Cesium (137Cs) was 10 times smaller around Fukushima-1 compared with around Chernobyl. The differences in the accident process are reflected in the composition of the discharged radioactivity as well as in the composition of the ground contamination. Volatile radionuclides (such as 132Te-132I, 131I, 134Cs and 137Cs) contributed to the gamma-ray exposure from the ground contamination around Fukishima-1, whereas a greater variety of radionuclides contributed significantly around Chernobyl. When radioactivity deposition occurred, the radiation exposure rate near Chernobyl is estimated to have been 770 μGy h−1 per initial 137Cs deposition of 1000 kBq m−2, whereas it was 100 μGy h−1 around Fukushima-1. Estimates of the cumulative exposure for 30 years are 970 and 570 mGy per initial deposition of 1000 kBq m−2 for Chernobyl and Fukusima-1, respectively. Of these exposures, 49 and 98% were contributed by radiocesiums (134Cs + 137Cs) around Chernobyl and Fukushima-1, respectively. PMID:26568603

  9. Geocenter Coordinates from a Combined Processing of LEO and Ground-based GPS Observations

    Science.gov (United States)

    Männel, Benjamin; Rothacher, Markus

    2017-04-01

    The GPS observations provided by the global IGS (International GNSS Service) tracking network play an important role for the realization of a unique terrestrial reference frame that is accurate enough to allow the monitoring of the Earth's system. Combining these ground-based data with GPS observations tracked by high-quality dual-frequency receivers on-board Low Earth Orbiters (LEO) might help to further improve the realization of the terrestrial reference frame and the estimation of the geocenter coordinates, GPS satellite orbits and Earth rotation parameters (ERP). To assess the scope of improvement, we processed a network of 50 globally distributed and stable IGS-stations together with four LEOs (GRACE-A, GRACE-B, OSTM/Jason-2 and GOCE) over a time interval of three years (2010-2012). To ensure fully consistent solutions the zero-difference phase observations of the ground stations and LEOs were processed in a common least-square adjustment, estimating GPS orbits, LEO orbits, station coordinates, ERPs, site-specific tropospheric delays, satellite and receiver clocks and ambiguities. We present the significant impact of the individual LEOs and a combination of all four LEOs on geocenter coordinates derived by using a translational approach (also called network shift approach). In addition, we present geocenter coordinates derived from the same set of GPS observations by using a unified approach. This approach combines the translational and the degree-one approach by estimating translations and surface deformations simultaneously. Based on comparisons against each other and against geocenter time series derived by other techniques the effect of the selected approach is assessed.

  10. Multi-contact Variable-Compliance Manipulation in Extreme Clutter

    Science.gov (United States)

    2014-06-16

    tactile pixel.’ Each patch is supplied with 5V via a pull-up resister and an Arduino board. The outer conductive layer is a single sheet covering the...entire sleeve, and is connected to the ground of the Arduino . As the 13 central resistive fabric is compressed, the conductivity across the compressed...portion of the fabric increases, and a drop in voltage can be detected by the Arduino in the circuit of the underlying taxel. This process is nonlinear

  11. Validating determinants for an alternate foot placement selection algorithm during human locomotion in cluttered terrain.

    Science.gov (United States)

    Moraes, Renato; Allard, Fran; Patla, Aftab E

    2007-10-01

    The goal of this study was to validate dynamic stability and forward progression determinants for the alternate foot placement selection algorithm. Participants were asked to walk on level ground and avoid stepping, when present, on a virtual white planar obstacle. They had a one-step duration to select an alternate foot placement, with the task performed under two conditions: free (participants chose the alternate foot placement that was appropriate) and forced (a green arrow projected over the white planar obstacle cued the alternate foot placement). To validate the dynamic stability determinant, the distance between the extrapolated center of mass (COM) position, which incorporates the dynamics of the body, and the limits of the base of support was calculated in both anteroposterior (AP) and mediolateral (ML) directions in the double support phase. To address the second determinant, COM deviation from straight ahead was measured between adaptive and subsequent steps. The results of this study showed that long and lateral choices were dominant in the free condition, and these adjustments did not compromise stability in both adaptive and subsequent steps compared with the short and medial adjustments, which were infrequent and adversely affected stability. Therefore stability is critical when selecting an alternate foot placement in a cluttered terrain. In addition, changes in the plane of progression resulted in small deviations of COM from the endpoint goal. Forward progression of COM was maintained even for foot placement changes in the frontal plane, validating this determinant as part of the selection algorithm.

  12. Vibrating Ground Target Detection and Feature Extraction of One-stationary Bistatic Frequency-modulated Continuous-wave Synthetic Aperture Radar

    Directory of Open Access Journals (Sweden)

    Liang Ying

    2015-12-01

    Full Text Available One of the unique characteristics of a ground target is its micro-motion, which can be used for target classification and identification. In this study, methods for vibrating ground target detection and feature extraction of the one-stationary bistatic frequency-modulated continuous-wave Synthetic Aperture Radar (SAR are studied. The Displaced Phase Center Antenna (DPCA technique is adopted to suppress the ground clutter, allowing the ground-vibrating targets to be detected. Analysis of the received signal indicates that the DPCA processing results in a slow time-varying envelope, known as the Slow Time Envelope (STE. The STE has a direct effect on the micro-Doppler time-frequency curve, which therefore cannot be obtained unbroken. Furthermore, vibrating features are extracted by utilizing their relationship with the STE term. Finally, some simulations are provided to validate the theoretical derivation and effectiveness of the proposed extraction method.

  13. The process of patient enablement in general practice nurse consultations: a grounded theory study.

    Science.gov (United States)

    Desborough, Jane; Banfield, Michelle; Phillips, Christine; Mills, Jane

    2017-05-01

    The aim of this study was to gain insight into the process of patient enablement in general practice nursing consultations. Enhanced roles for general practice nurses may benefit patients through a range of mechanisms, one of which may be increasing patient enablement. In studies with general practitioners enhanced patient enablement has been associated with increases in self-efficacy and skill development. This study used a constructivist grounded theory design. In-depth interviews were conducted with 16 general practice nurses and 23 patients from 21 general practices between September 2013 - March 2014. Data generation and analysis were conducted concurrently using constant comparative analysis and theoretical sampling focussing on the process and outcomes of patient enablement. Use of the storyline technique supported theoretical coding and integration of the data into a theoretical model. A clearly defined social process that fostered and optimised patient enablement was constructed. The theory of 'developing enabling healthcare partnerships between nurses and patients in general practice' incorporates three stages: triggering enabling healthcare partnerships, tailoring care and the manifestation of patient enablement. Patient enablement was evidenced through: 1. Patients' understanding of their unique healthcare requirements informing their health seeking behaviours and choices; 2. Patients taking an increased lead in their partnership with a nurse and seeking choices in their care and 3. Patients getting health care that reflected their needs, preferences and goals. This theoretical model is in line with a patient-centred model of health care and is particularly suited to patients with chronic disease. © 2016 John Wiley & Sons Ltd.

  14. Ingredients and change processes in occupational therapy for children: a grounded theory study.

    Science.gov (United States)

    Armitage, Samantha; Swallow, Veronica; Kolehmainen, Niina

    2017-05-01

    There is limited evidence about the effectiveness of occupational therapy interventions for participation outcomes in children with coordination difficulties. Developing theory about the interventions, i.e. their ingredients and change processes, is the first step to advance the evidence base. To develop theory about the key ingredients of occupational therapy interventions for children with coordination difficulties and the processes through which change in participation might happen. Grounded theory methodology, as described by Kathy Charmaz, was used to develop the theory. Children and parents participated in semi-structured interviews to share their experiences of occupational therapy and processes of change. Data collection and analysis were completed concurrently using constant comparison methods. Five key ingredients of interventions were described: performing activities and tasks; achieving; carer support; helping and supporting the child; and labelling. Ingredients related to participation by changing children's mastery experience, increasing capability beliefs and sense of control. Parents' knowledge, skills, positive emotions, sense of empowerment and capability beliefs also related to children's participation. The results identify intervention ingredients and change pathways within occupational therapy to increase participation. It is unclear how explicitly and often therapists consider and make use of these ingredients and pathway.

  15. Occupational therapy students in the process of interprofessional collaborative learning: a grounded theory study.

    Science.gov (United States)

    Howell, Dana

    2009-01-01

    The purpose of this grounded theory study was to generate a theory of the interprofessional collaborative learning process of occupational therapy (OT) students who were engaged in a collaborative learning experience with students from other allied health disciplines. Data consisted of semi-structured interviews with nine OT students from four different interprofessional collaborative learning experiences at three universities. The emergent theory explained OT students' need to build a culture of mutual respect among disciplines in order to facilitate interprofessional collaborative learning. Occupational therapy students went through a progression of learned skills that included learning how to represent the profession of OT, hold their weight within a team situation, solve problems collaboratively, work as a team, and ultimately, to work in an actual team in practice. This learning process occurred simultaneously as students also learned course content. The students had to contend with barriers and facilitators that influenced their participation and the success of their collaboration. Understanding the interprofessional learning process of OT students will help allied health faculty to design more effective, inclusive interprofessional courses.

  16. A Grounded Theory Study of the Mentoring Process Involved With Undergraduate Athletic Training Students.

    Science.gov (United States)

    Pitney, William A; Ehlers, Greg G

    2004-12-01

    OBJECTIVE: To gain insight regarding the mentoring processes involving students enrolled in athletic training education programs and to create a mentoring model. DESIGN AND SETTING: We conducted a grounded theory study with students and mentors currently affiliated with 1 of 2 of the athletic training education programs accredited by the Commission on Accreditation of Allied Health Education Programs. PARTICIPANTS: Sixteen interviews were conducted, 13 with athletic training students and 3 with individuals identified as mentors. The students ranged in age from 20 to 24 years, with an average of 21.6 years. The mentors ranged from 24 to 38 years of age, with an average of 33.3 years. Participants were purposefully selected based on theoretic sampling and availability. DATA ANALYSIS: The transcribed interviews were analyzed using open-, axial-, and selective-coding procedures. Member checks, peer debriefings, and triangulation were used to ensure trustworthiness. RESULTS: Students who acknowledged having a mentor overwhelmingly identified their clinical instructor in this role. The open-coding procedures produced 3 categories: (1) mentoring prerequisites, (2) interpersonal foundations, and (3) educational dimensions. Mentoring prerequisites included accessibility, approachability, and protege initiative. Interpersonal foundations involved the mentor and protege having congruent values, trust, and a personal relationship. The educational dimensions category involved the mentor facilitating knowledge and skill development, encouraging professional perspectives, and individualizing learning. Although a student-certified athletic trainer relationship can be grounded in either interpersonal or educational aspects, the data support the occurrence of an authentic mentoring relationship when the dimensions coalesced. CONCLUSIONS: Potential mentors must not only be accessible but also approachable by a prospective protege. Mentoring takes initiative on behalf of a student and

  17. Redefining fine roots improves understanding of below-ground contributions to terrestrial biosphere processes.

    Science.gov (United States)

    McCormack, M Luke; Dickie, Ian A; Eissenstat, David M; Fahey, Timothy J; Fernandez, Christopher W; Guo, Dali; Helmisaari, Heljä-Sisko; Hobbie, Erik A; Iversen, Colleen M; Jackson, Robert B; Leppälammi-Kujansuu, Jaana; Norby, Richard J; Phillips, Richard P; Pregitzer, Kurt S; Pritchard, Seth G; Rewald, Boris; Zadworny, Marcin

    2015-08-01

    Fine roots acquire essential soil resources and mediate biogeochemical cycling in terrestrial ecosystems. Estimates of carbon and nutrient allocation to build and maintain these structures remain uncertain because of the challenges of consistently measuring and interpreting fine-root systems. Traditionally, fine roots have been defined as all roots ≤ 2 mm in diameter, yet it is now recognized that this approach fails to capture the diversity of form and function observed among fine-root orders. Here, we demonstrate how order-based and functional classification frameworks improve our understanding of dynamic root processes in ecosystems dominated by perennial plants. In these frameworks, fine roots are either separated into individual root orders or functionally defined into a shorter-lived absorptive pool and a longer-lived transport fine-root pool. Using these frameworks, we estimate that fine-root production and turnover represent 22% of terrestrial net primary production globally - a c. 30% reduction from previous estimates assuming a single fine-root pool. Future work developing tools to rapidly differentiate functional fine-root classes, explicit incorporation of mycorrhizal fungi into fine-root studies, and wider adoption of a two-pool approach to model fine roots provide opportunities to better understand below-ground processes in the terrestrial biosphere.

  18. Contextual learning in ground-penetrating radar data using Dirichlet process priors

    Science.gov (United States)

    Ratto, Christopher R.; Morton, Kenneth D., Jr.; Collins, Leslie M.; Torrione, Peter A.

    2011-06-01

    In landmine detection applications, fluctuation of environmental and operating conditions can limit the performance of sensors based on ground-penetrating radar (GPR) technology. As these conditions vary, the classification and fusion rules necessary for achieving high detection and low false alarm rates may change. Therefore, context-dependent learning algorithms that exploit contextual variations of GPR data to alter decision rules have been considered for improving the performance of landmine detection systems. Past approaches to contextual learning have used both generative and discriminative methods to learn a probabilistic mixture of contexts, such as a Gaussian mixture, fuzzy c-means clustering, or a mixture of random sets. However, in these approaches the number of mixture components is pre-defined, which could be problematic if the number of contexts in a data collection is unknown a priori. In this work, a generative context model is proposed which requires no a priori knowledge in the number of mixture components. This was achieved through modeling the contextual distribution in a physics-based feature space with a Gaussian mixture, while also incorporating a Dirichlet process prior to model uncertainty in the number of mixture components. This Dirichlet process Gaussian mixture model (DPGMM) was then incorporated in the previously-developed Context-Dependent Feature Selection (CDFS) framework for fusion of multiple landmine detection algorithms. Experimental results suggest that when the DPGMM was incorporated into CDFS, the degree of performance improvement over conventional fusion was greater than when a conventional fixed-order context model was used.

  19. A Grounded Theory Approach in a Branding Context: Challenges and lessons learnt during the research process

    Directory of Open Access Journals (Sweden)

    Anne Rindell, PhD.

    2009-06-01

    Full Text Available The purpose of this paper is to discuss challenges and lessons learnt when conducting a classic grounded theory study in a marketing context. The paper focuses on two specific challenges that were met during a specific research process. The first challenge related to positioning the study, namely, specifying“what the study is a study of”. The second challenge concerned the choice between formal or substantive theory. Both challenges were accentuated as the emerged core category concerned a phenomenon that has caught less attention in marketing, that is, the temporal dimension in corporate images. By the temporal dimension in corporate images we mean that corporate images often have roots in earlier times through consumer memories. In other words, consumers are not tabula rasa, that is, blank sheets of paper on which communication messages can be printed. Rather, consumers have a pre-understanding of the company that works as an interpretation framework for company actions in the present. The lessons learnt from this research process can be summarized as “stay faithful to the data”, “write memos on issues you reflect upon although they might be in another substantial field” as they might become useful later, and, “look into thinking in other disciplines” as disciplines do not develop equally.

  20. Intermittent Clutter Removal Approac for wind Profiler Data Based on Fractional Fourier Transform

    Institute of Scientific and Technical Information of China (English)

    YUAN Lei; AN Jian-ping; BU Xiang-yuan

    2009-01-01

    Through the analysis of the target characteristics and according to the intermittent clutter bursting and short duration characteristics, a new method for the clutter recognition based on the fractional Fourier transform (FRFT) is proposed. This method is predicated on the fact that the FRFT perfectly localizes a chirp signal as an impulse when the angle parameter of the transform matches the chirp rate of the chirp signal. The method involves detecting the presence of the intermittent clutter and correctly estimating its orientation in the time-frequency plane, removing the intermittent clutter in the fractional domain, and completing wind estimation by the power spectrum. By testing the artificial WPR-like signal and data measured from the field, we verify that the FRFT-based method is very effective.

  1. Clutter attenuation using the Doppler effect in standoff electromagnetic quantum sensing

    Science.gov (United States)

    Lanzagorta, Marco; Jitrik, Oliverio; Uhlmann, Jeffrey; Venegas, Salvador

    2016-05-01

    In the context of traditional radar systems, the Doppler effect is crucial to detect and track moving targets in the presence of clutter. In the quantum radar context, however, most theoretical performance analyses to date have assumed static targets. In this paper we consider the Doppler effect at the single photon level. In particular, we describe how the Doppler effect produced by clutter and moving targets modifies the quantum distinguishability and the quantum radar error detection probability equations. Furthermore, we show that Doppler-based delayline cancelers can reduce the effects of clutter in the context of quantum radar, but only in the low-brightness regime. Thus, quantum radar may prove to be an important technology if the electronic battlefield requires stealthy tracking and detection of moving targets in the presence of clutter.

  2. Comparing Image-Based Methods for Assessing Visual Clutter in Generalized Maps

    Science.gov (United States)

    Touya, G.; Decherf, B.; Lalanne, M.; Dumont, M.

    2015-08-01

    Map generalization abstracts and simplifies geographic information to derive maps at smaller scales. The automation of map generalization requires techniques to evaluate the global quality of a generalized map. The quality and legibility of a generalized map is related to the complexity of the map, or the amount of clutter in the map, i.e. the excessive amount of information and its disorganization. Computer vision research is highly interested in measuring clutter in images, and this paper proposes to compare some of the existing techniques from computer vision, applied to generalized maps evaluation. Four techniques from the literature are described and tested on a large set of maps, generalized at different scales: edge density, subband entropy, quad tree complexity, and segmentation clutter. The results are analyzed against several criteria related to generalized maps, the identification of cluttered areas, the preservation of the global amount of information, the handling of occlusions and overlaps, foreground vs background, and blank space reduction.

  3. COMPARING IMAGE-BASED METHODS FOR ASSESSING VISUAL CLUTTER IN GENERALIZED MAPS

    Directory of Open Access Journals (Sweden)

    G. Touya

    2015-08-01

    Full Text Available Map generalization abstracts and simplifies geographic information to derive maps at smaller scales. The automation of map generalization requires techniques to evaluate the global quality of a generalized map. The quality and legibility of a generalized map is related to the complexity of the map, or the amount of clutter in the map, i.e. the excessive amount of information and its disorganization. Computer vision research is highly interested in measuring clutter in images, and this paper proposes to compare some of the existing techniques from computer vision, applied to generalized maps evaluation. Four techniques from the literature are described and tested on a large set of maps, generalized at different scales: edge density, subband entropy, quad tree complexity, and segmentation clutter. The results are analyzed against several criteria related to generalized maps, the identification of cluttered areas, the preservation of the global amount of information, the handling of occlusions and overlaps, foreground vs background, and blank space reduction.

  4. A Polarization Technique for Mitigating Low Grazing Angle Radar Sea Clutter

    Science.gov (United States)

    2017-03-03

    A Polarization Technique for Mitigating Low-Grazing-Angle Radar Sea Clutter Molly K. Crane MIT Lincoln Laboratory Lexington, MA 02420 Email...MA 02420 Email: mabel.ramirez@ll.mit.edu Abstract—Traditional detection schemes in conventional mar- itime surveillance radars may suffer serious...effective means of enhancing target detection in sea clutter, MIT Lincoln Laboratory (MIT LL) collected a fully polarimetric X-band radar dataset on

  5. Analysis and Modeling of Multistatic Clutter and Reverberation and Support for the FORA

    Science.gov (United States)

    2014-09-30

    ABSTRACT Same as Report ( SAR ) 18. NUMBER OF PAGES 8 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b. ABSTRACT unclassified c. THIS...effort, the PI completed work to statistically characterize the bistatic bottom clutter and shipwreck echoes seen in the Clutter07 data sets using...Reverberation Modeling Workshop proceedings, Apr. 2007. [14] Dale D. Ellis, John R. Preston, Paul C. Hines, and Victor W. Young, Bistatic signal excess

  6. Advanced methods and means to improve atmospheric lidar stability against sky background clutter

    Science.gov (United States)

    Agishev, Ravil R.

    2011-11-01

    An impact of intensive background clutter on lidar photodetectors leads to changes of their sensitivity and can even overload them. As a result, information on atmospheric optical parameters is distorted and sometimes can be completely lost. Since a problem of lidar system structure and parameters adaptation to background radiation remains actual one, some advanced methods and means to improve atmospheric lidar stability against sky background clutter are discussed.

  7. 机载MIMO 雷达3-CAP杂波抑制方法%3-CAP Clutter Suppression Method Research for Airborne Radar

    Institute of Scientific and Technical Information of China (English)

    郝琳; 张永顺; 李哲

    2014-01-01

    To solve the problem of clutter suppression faced by airborned MIMO radar,after considering the element error,channel uncertainty as well as clutter fluctuation,,the clutter model for airborne MIMO ra-dar under different error conditions is established,a new space-time adaptive processing method based on MIMO systems---M3-CAP method is proposed.Firstly,temporal filtering is performed on the space-time received data,and then the output data of three Doppler channels which are the detected Doppler channel and two of its adj acent channels,is adaptively filtered .By combining MIMO systems and 3-CAP method ef-fectively,the advantage of waveform diversity is extended into 3-CAP method,this new method improves the degree of freedom and clutter estimation accuracy.By analyzing and comparing the clutter suppression performance under different radar systems and different error conditions,the result turns out:the clutter suppression performance of M3-CAP method is superior to JDL-GMB、Modified JDL、3-CAP methods.%针对机载雷达面临的杂波抑制问题,在考虑阵元误差、通道误差和杂波起伏等误差因素对杂波特性影响的基础上,建立了机载 MIMO 雷达杂波数学模型,提出了一种基于 MIMO 雷达体制下的空时自适应新方法---M3-CAP方法。对接收信号进行时域滤波,选取被检测通道与其2个相邻通道为一组,进行自适应处理。该方法通过MIMO 技术与3-CAP 方法的有效结合,将波形分集的优势扩展到3-CAP方法中,显著提高了雷达系统自由度和杂波协方差矩阵估计精度。通过对不同雷达体制以及不同误差条件下杂波抑制性能的分析比较,结果表明:提出的M3-CAP方法的杂波抑制性能明显优于JDL-GMB、改进的JDL、3-CAP等方法。

  8. Developing a Logistics Data Process for Support Equipment for NASA Ground Operations

    Science.gov (United States)

    Chakrabarti, Suman

    2010-01-01

    The United States NASA Space Shuttle has long been considered an extremely capable yet relatively expensive rocket. A great part of the roughly US $500 million per launch expense was the support footprint: refurbishment and maintenance of the space shuttle system, together with the long list of resources required to support it, including personnel, tools, facilities, transport and support equipment. NASA determined to make its next rocket system with a smaller logistics footprint, and thereby more cost-effective and quicker turnaround. The logical solution was to adopt a standard Logistics Support Analysis (LSA) process based on GEIA-STD-0007 http://www.logisticsengineers.org/may09pres/GEIASTD0007DEXShortIntro.pdf which is the successor of MIL-STD-1388-2B widely used by U.S., NATO, and other world military services and industries. This approach is unprecedented at NASA: it is the first time a major program of programs, Project Constellation, is factoring logistics and supportability into design at many levels. This paper will focus on one of those levels NASA ground support equipment for the next generation of NASA rockets and on building a Logistics Support Analysis Record (LSAR) for developing and documenting a support solution and inventory of resources for. This LSAR is actually a standards-based database, containing analyses of the time and tools, personnel, facilities and support equipment required to assemble and integrate the stages and umbilicals of a rocket. This paper will cover building this database from scratch: including creating and importing a hierarchical bill of materials (BOM) from legacy data; identifying line-replaceable units (LRUs) of a given piece of equipment; analyzing reliability and maintainability of said LRUs; and therefore making an assessment back to design whether the support solution for a piece of equipment is too much work, i.e., too resource-intensive. If one must replace or inspect an LRU too much, perhaps a modification of

  9. Developing a Logistics Data Process for Support Equipment for NASA Ground Operations

    Science.gov (United States)

    Chakrabarti, Suman

    2010-01-01

    The United States NASA Space Shuttle has long been considered an extremely capable yet relatively expensive rocket. A great part of the roughly US $500 million per launch expense was the support footprint: refurbishment and maintenance of the space shuttle system, together with the long list of resources required to support it, including personnel, tools, facilities, transport and support equipment. NASA determined to make its next rocket system with a smaller logistics footprint, and thereby more cost-effective and quicker turnaround. The logical solution was to adopt a standard Logistics Support Analysis (LSA) process based on GEIA-STD-0007 http://www.logisticsengineers.org/may09pres/GEIASTD0007DEXShortIntro.pdf which is the successor of MIL-STD-1388-2B widely used by U.S., NATO, and other world military services and industries. This approach is unprecedented at NASA: it is the first time a major program of programs, Project Constellation, is factoring logistics and supportability into design at many levels. This paper will focus on one of those levels NASA ground support equipment for the next generation of NASA rockets and on building a Logistics Support Analysis Record (LSAR) for developing and documenting a support solution and inventory of resources for. This LSAR is actually a standards-based database, containing analyses of the time and tools, personnel, facilities and support equipment required to assemble and integrate the stages and umbilicals of a rocket. This paper will cover building this database from scratch: including creating and importing a hierarchical bill of materials (BOM) from legacy data; identifying line-replaceable units (LRUs) of a given piece of equipment; analyzing reliability and maintainability of said LRUs; and therefore making an assessment back to design whether the support solution for a piece of equipment is too much work, i.e., too resource-intensive. If one must replace or inspect an LRU too much, perhaps a modification of

  10. Using an improved SIFT algorithm and fuzzy closed-loop control strategy for object recognition in cluttered scenes.

    Science.gov (United States)

    Nie, Haitao; Long, Kehui; Ma, Jun; Yue, Dan; Liu, Jinguo

    2015-01-01

    Partial occlusions, large pose variations, and extreme ambient illumination conditions generally cause the performance degradation of object recognition systems. Therefore, this paper presents a novel approach for fast and robust object recognition in cluttered scenes based on an improved scale invariant feature transform (SIFT) algorithm and a fuzzy closed-loop control method. First, a fast SIFT algorithm is proposed by classifying SIFT features into several clusters based on several attributes computed from the sub-orientation histogram (SOH), in the feature matching phase only features that share nearly the same corresponding attributes are compared. Second, a feature matching step is performed following a prioritized order based on the scale factor, which is calculated between the object image and the target object image, guaranteeing robust feature matching. Finally, a fuzzy closed-loop control strategy is applied to increase the accuracy of the object recognition and is essential for autonomous object manipulation process. Compared to the original SIFT algorithm for object recognition, the result of the proposed method shows that the number of SIFT features extracted from an object has a significant increase, and the computing speed of the object recognition processes increases by more than 40%. The experimental results confirmed that the proposed method performs effectively and accurately in cluttered scenes.

  11. New adaptive clutter rejection for ultrasound color Doppler imaging: in vivo study.

    Science.gov (United States)

    Yoo, Yang Mo; Kim, Yongmin

    2010-03-01

    Clutter rejection is essential for accurate flow estimation in ultrasound color Doppler imaging. In this article, we present a new adaptive clutter rejection (ACR) technique where an optimum filter is dynamically selected depending upon the underlying clutter characteristics (e.g., tissue acceleration and power). We compared the performance of the ACR method with other adaptive methods, i.e., down-mixing (DM) and adaptive clutter filtering (ACF), using in vivo data acquired from the kidney, liver and common carotid artery. With the kidney data, the ACR method provided an average improvement of 3.05 dB and 1.7 dB in flow signal-to-clutter ratio (SCR) compared with DM and ACF, respectively. With the liver data, SCR was improved by 2.75 dB and 1.8 dB over DM and ACF while no significant improvement with ACR was found in the common carotid artery data. Thus, the proposed adaptive method could provide more accurate flow estimation by improving clutter rejection in abdominal ultrasound color Doppler imaging pending validation.

  12. Eigen-based clutter filter design for ultrasound color flow imaging: a review.

    Science.gov (United States)

    Yu, Alfred; Lovstakken, Lasse

    2010-05-01

    Proper suppression of tissue clutter is a prerequisite for visualizing flow accurately in ultrasound color flow imaging. Among various clutter suppression methods, the eigen-based filter has shown potential because it can theoretically adapt its stopband to the actual clutter characteristics even when tissue motion is present. This paper presents a formative review on how eigen-based filters should be designed to improve their practical efficacy in adaptively suppressing clutter without affecting the blood flow echoes. Our review is centered around a comparative assessment of two eigen-filter design considerations: 1) eigen-component estimation approach (single-ensemble vs. multi-ensemble formulations), and 2) filter order selection mechanism (eigenvalue-based vs. frequencybased algorithms). To evaluate the practical efficacy of existing eigen-filter designs, we analyzed their clutter suppression level in two in vivo scenarios with substantial tissue motion (intra-operative coronary imaging and thyroid imaging). Our analysis shows that, as compared with polynomial regression filters (with or without instantaneous clutter downmixing), eigen-filters that use a frequency-based algorithm for filter order selection generally give Doppler power images with better contrast between blood and tissue regions. Results also suggest that both multi-ensemble and single-ensemble eigen-estimation approaches have their own advantages and weaknesses in different imaging scenarios. It may be beneficial to develop an algorithmic way of defining the eigen-filter formulation so that its performance advantages can be better realized.

  13. Signal Processing System for the CASA Integrated Project I Radars

    Energy Technology Data Exchange (ETDEWEB)

    Bharadwaj, Nitin; Chandrasekar, V.; Junyent, Francesc

    2010-09-01

    This paper describes the waveform design space and signal processing system for dual-polarization Doppler weather radar operating at X band. The performance of the waveforms is presented with ground clutter suppression capability and mitigation of range velocity ambiguity. The operational waveform is designed based on operational requirements and system/hardware requirements. A dual Pulse Repetition Frequency (PRF) waveform was developed and implemented for the first generation X-band radars deployed by the Center for Collaborative Adaptive Sensing of the Atmosphere (CASA). This paper presents an evaluation of the performance of the waveforms based on simulations and data collected by the first-generation CASA radars during operations.

  14. 机载共形相控阵雷达二维杂波建模与分析%Space-Time Clutter Model and Analysis for Airborne Radar With Conformal Phased Array Antenna

    Institute of Scientific and Technical Information of China (English)

    汤子跃; 王永良; 蒋兴舟

    2001-01-01

    分析了机载预警(AEW)雷达可能采用的横柱型和竖柱型这两种基本的共形相控阵的方向图特性,提出了其阵元的放置规律,对这两种机载侧视共形相控阵雷达的杂波进行了建模,并依此模型对这两种机载共形相控阵雷达的杂波数据进行了计算机仿真,通过杂波协方差矩阵的估计求得其空-时二维杂波谱,检验了杂波模型的准确性,所做工作将对实际的共形阵具有重要的指导意义,也为进一步研究机载共形相控阵雷达信号处理和杂波抑制的技术和方法奠定了基础。%The space-time clutter model and simulation of AEW (airborneearly warning) radar with conformal phased array are studied. The patterns of the two types of conformal are investigated, the principle of element placement is presented, a space-time clutter model is developed, and the characteristics of the space-time clutter are analyzed. The computer simulating of generating the space-time clutter data for a conformal phased array radar is discussed. Finally, the space-time clutter power-spectra are given by estimating the covariance matrix of space-time clutter, and the simulation result shows that the model is creditable. These results are available for further researching the space-time adaptive processing for practical conformal phased array radar.

  15. The CryoSat-2 Payload Data Ground Segment and Data Processing

    Science.gov (United States)

    Frommknecht, Bjoern; Parrinello, Tommaso; Badessi, Stefano; Mizzi, Loretta; Torroni, Vittorio

    2016-04-01

    Selected as the first Earth Explorer Opportunity mission and following the launch failure of Cryosat-1 in 2005, the Cryosat-2 mission was launched on the 8th April 2010 and it is the first European ice mission dedicated to monitoring precise changes in the thickness of polar ice sheets and floating sea ice over a baseline 3-year period. The main CryoSat-2 mission objectives can be summarised in the determination of the regional and basin-scale trends in perennial Arctic sea ice thickness and mass, and in the determination of regional and total contributions to global sea level of the Antarctic and Greenland Ice. Therefore, the observations made over the life time of the mission will provide conclusive evidence as to whether there is a trend towards diminishing polar ice cover and consequently improve our understanding of the relationship between ice and global climate change. Scope of this paper is to describe the Cryosat-2 Ground Segment present configuration and its main function to satisfy the Cryosat-2 mission requirements. In particular, the paper will highlight the current status of the processing of the SIRAL instrument L1b and L2 products, both for ocean and ice products, in terms of completeness and availability. Additional information will be also given on the PDGS current status and planned evolutions, including product and processor updates and associated reprocessing campaigns.

  16. Analysis of the decision-making process leading to appendectomy: a grounded theory study.

    Science.gov (United States)

    Larsson, Gerry; Weibull, Henrik; Larsson, Bodil Wilde

    2004-11-01

    The aim was to develop a theoretical understanding of the decision-making process leading to appendectomy. A qualitative interview study was performed in the grounded theory tradition using the constant comparative method to analyze data. The study setting was one county hospital and two local hospitals in Sweden, where 11 surgeons and 15 surgical nurses were interviewed. A model was developed which suggests that surgeons' decision making regarding appendectomy is formed by the interplay between their medical assessment of the patient's condition and a set of contextual characteristics. The latter consist of three interacting factors: (1) organizational conditions, (2) the professional actors' individual characteristics and interaction, and (3) the personal characteristics of the patient and his or her family or relatives. In case the outcome of medical assessment is ambiguous, the risk evaluation and final decision will be influenced by an interaction of the contextual characteristics. It was concluded that, compared to existing, rational models of decision making, the model presented identified potentially important contextual characteristics and an outline on when they come into play.

  17. Ground state correlations in Deep Inelastic Scattering and the Drell-Yan process

    CERN Document Server

    Linnyk, O; Mosel, U

    2004-01-01

    Non-perturbative corrections to the LO cross section formulae for DIS and the Drell-Yan process were calculated. The interaction of partons was taken into account via dressing the incoming quark lines with spectral functions. We found the effect of ground state correlation in DIS to be large in the region of small Bjorken x and low momentum transfer Q. For a quark width of the order of 200 MeV, the deviation from parton model cross section reaches as much as 50% for Q^2=10 GeV^2. On the other hand, for the values of Q well above the resonance region, the effect of ISI turned out to be small in DIS, but still substantial for the triple differential Drell-Yan cross section. Our calculations show that the shape of the high mass Drell-Yan pair transverse momentum distribution is fully determined by quark off-shellness. From comparison to the resent data on the Drell-Yan cross section from NuSea collaboration, we obtained for the quark width in the nucleon the value about 200 MeV.

  18. Experimental quantum key distribution with simulated ground-to-satellite photon losses and processing limitations

    Science.gov (United States)

    Bourgoin, Jean-Philippe; Gigov, Nikolay; Higgins, Brendon L.; Yan, Zhizhong; Meyer-Scott, Evan; Khandani, Amir K.; Lütkenhaus, Norbert; Jennewein, Thomas

    2015-11-01

    Quantum key distribution (QKD) has the potential to improve communications security by offering cryptographic keys whose security relies on the fundamental properties of quantum physics. The use of a trusted quantum receiver on an orbiting satellite is the most practical near-term solution to the challenge of achieving long-distance (global-scale) QKD, currently limited to a few hundred kilometers on the ground. This scenario presents unique challenges, such as high photon losses and restricted classical data transmission and processing power due to the limitations of a typical satellite platform. Here we demonstrate the feasibility of such a system by implementing a QKD protocol, with optical transmission and full post-processing, in the high-loss regime using minimized computing hardware at the receiver. Employing weak coherent pulses with decoy states, we demonstrate the production of secure key bits at up to 56.5 dB of photon loss. We further illustrate the feasibility of a satellite uplink by generating a secure key while experimentally emulating the varying losses predicted for realistic low-Earth-orbit satellite passes at 600 km altitude. With a 76 MHz source and including finite-size analysis, we extract 3374 bits of a secure key from the best pass. We also illustrate the potential benefit of combining multiple passes together: while one suboptimal "upper-quartile" pass produces no finite-sized key with our source, the combination of three such passes allows us to extract 165 bits of a secure key. Alternatively, we find that by increasing the signal rate to 300 MHz it would be possible to extract 21 570 bits of a secure finite-sized key in just a single upper-quartile pass.

  19. Signature of magmatic processes in ground deformation signals from Phlegraean Fields (Italy)

    Science.gov (United States)

    Bagagli, Matteo; Montagna, Chiara Paola; Longo, Antonella; Papale, Paolo

    2016-04-01

    Ground deformation signals such as dilatometric and tiltmetric ones, are nowadays well studied from the vulcanological community all over the world. These signals can be used to retrieve information on volcanoes state and to study the magma dynamics in their plumbing system. We compared synthetic signals in the Very Long Period (VLP, 10-2 - 10-1 Hz) and Ultra Long Period (ULP, 10-4 - 10-2 Hz) bands obtained from the simulation of magma mixing in shallow reservoirs ([3],[4]) with real data obtained from the dilatometers and tiltmeters network situated in the Phlegraean Fields near Naples (Italy), in order to define and constrain the relationships between them. Analyses of data from the October 2006 seismic swarm in the area show that the frequency spectrum of the synthetics is remarkably similar to the transient present in the real signals. In depth studies with accurated techniques for spectral analysis (i.e wavelet transform) and application of this method to other time windows have identified in the bandwidth around 10-4Hz (between 1h30m and 2h45m) peaks that are fairly stable and independent from the processing carried out on the full-band signal. These peaks could be the signature of ongoing convection at depth. It is well known that re-injection of juvenile magmas can reactivate the eruption dynamics ([1],[2]), thus being able to define mixing markers and detect them in the ground deformation signals is a relevant topic in order to understand the dynamics of active and quiescent vulcanoes and to eventually improve early-warning methods for impending eruptions. [1] Arienzo, I. et al. (2010). "The feeding system of Agnano-Monte Spina eruption (Campi Flegrei, Italy): dragging the past into present activity and future scenarios". In: Chemical Geology 270.1, pp. 135-147. [2] Bachmann, Olivier and George Bergantz (2008). "The magma reservoirs that feed supereruptions". In: Elements 4.1, pp. 17-21. [3] Longo, Antonella et al. (2012). "Magma convection and mixing

  20. Suitability of ground-based SfM-MVS for monitoring glacial and periglacial processes

    Science.gov (United States)

    Piermattei, Livia; Carturan, Luca; de Blasi, Fabrizio; Tarolli, Paolo; Dalla Fontana, Giancarlo; Vettore, Antonio; Pfeifer, Norbert

    2016-05-01

    Photo-based surface reconstruction is rapidly emerging as an alternative survey technique to lidar (light detection and ranging) in many fields of geoscience fostered by the recent development of computer vision algorithms such as structure from motion (SfM) and dense image matching such as multi-view stereo (MVS). The objectives of this work are to test the suitability of the ground-based SfM-MVS approach for calculating the geodetic mass balance of a 2.1 km2 glacier and for detecting the surface displacement of a neighbouring active rock glacier located in the eastern Italian Alps. The photos were acquired in 2013 and 2014 using a digital consumer-grade camera during single-day field surveys. Airborne laser scanning (ALS, otherwise known as airborne lidar) data were used as benchmarks to estimate the accuracy of the photogrammetric digital elevation models (DEMs) and the reliability of the method. The SfM-MVS approach enabled the reconstruction of high-quality DEMs, which provided estimates of glacial and periglacial processes similar to those achievable using ALS. In stable bedrock areas outside the glacier, the mean and the standard deviation of the elevation difference between the SfM-MVS DEM and the ALS DEM was -0.42 ± 1.72 and 0.03 ± 0.74 m in 2013 and 2014, respectively. The overall pattern of elevation loss and gain on the glacier were similar with both methods, ranging between -5.53 and + 3.48 m. In the rock glacier area, the elevation difference between the SfM-MVS DEM and the ALS DEM was 0.02 ± 0.17 m. The SfM-MVS was able to reproduce the patterns and the magnitudes of displacement of the rock glacier observed by the ALS, ranging between 0.00 and 0.48 m per year. The use of natural targets as ground control points, the occurrence of shadowed and low-contrast areas, and in particular the suboptimal camera network geometry imposed by the morphology of the study area were the main factors affecting the accuracy of photogrammetric DEMs negatively

  1. Below-ground process responses to elevated CO2 and temperature: a discussion of observations, measurement methods, and models

    Science.gov (United States)

    Elise Pendall; Scott Bridgham; Paul J. Hanson; Bruce Hungate; David W. Kicklighter; Dale W. Johnson; Beverly E. Law; Yiqi Luo; J. Patrick Megonigal; Maria Olsrud; Michael G. Ryan; Shiqiang Wan

    2004-01-01

    Rising atmospheric CO2 and temperatures are probably altering ecosystem carbon cycling, causing both positive and negative feedbacks to climate. Below-ground processes play a key role in the global carbon (C) cycle because they regulate storage of large quantities of C, and are potentially very sensitive to direct and indirect effects of elevated...

  2. Plug and Play Realtime Diagnosis for Ground Processing System Integration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's "Ground Systems Development and Operations Program" is moving towards transforming parts of the Kennedy Space Center from a historically government-only...

  3. On-Ground Processing of Yaogan-24 Remote Sensing Satellite Attitude Data and Verification Using Geometric Field Calibration.

    Science.gov (United States)

    Wang, Mi; Fan, Chengcheng; Yang, Bo; Jin, Shuying; Pan, Jun

    2016-07-30

    Satellite attitude accuracy is an important factor affecting the geometric processing accuracy of high-resolution optical satellite imagery. To address the problem whereby the accuracy of the Yaogan-24 remote sensing satellite's on-board attitude data processing is not high enough and thus cannot meet its image geometry processing requirements, we developed an approach involving on-ground attitude data processing and digital orthophoto (DOM) and the digital elevation model (DEM) verification of a geometric calibration field. The approach focuses on three modules: on-ground processing based on bidirectional filter, overall weighted smoothing and fitting, and evaluation in the geometric calibration field. Our experimental results demonstrate that the proposed on-ground processing method is both robust and feasible, which ensures the reliability of the observation data quality, convergence and stability of the parameter estimation model. In addition, both the Euler angle and quaternion could be used to build a mathematical fitting model, while the orthogonal polynomial fitting model is more suitable for modeling the attitude parameter. Furthermore, compared to the image geometric processing results based on on-board attitude data, the image uncontrolled and relative geometric positioning result accuracy can be increased by about 50%.

  4. The ground side of an object: perceived as shapeless yet processed for semantics.

    Science.gov (United States)

    Sanguinetti, Joseph L; Allen, John J B; Peterson, Mary A

    2014-01-01

    Traditional theories of perception posit that only objects access semantics; abutting, patently shapeless grounds do not. Surprisingly, this assumption has been untested until now. In two experiments, participants classified silhouettes as depicting meaningful real-world or meaningless novel objects while event-related potentials (ERPs) were recorded. The borders of half of the novel objects suggested portions of meaningful objects on the ground side. Participants were unaware of these meaningful objects because grounds are perceived as shapeless. In Experiment 1, in which silhouettes were presented twice, N400 ERP repetition effects indicated that semantics were accessed for novel silhouettes that suggested meaningful objects in the ground and for silhouettes that depicted real-world objects, but not for novel silhouettes that did not suggest meaningful objects in the ground. In Experiment 2, repetition was manipulated via matching prime words. This experiment replicated the effect observed in Experiment 1. These experiments provide the first neurophysiological evidence that semantic access can occur for the apparently shapeless ground side of a border.

  5. Audio-visual speech timing sensitivity is enhanced in cluttered conditions.

    Directory of Open Access Journals (Sweden)

    Warrick Roseboom

    Full Text Available Events encoded in separate sensory modalities, such as audition and vision, can seem to be synchronous across a relatively broad range of physical timing differences. This may suggest that the precision of audio-visual timing judgments is inherently poor. Here we show that this is not necessarily true. We contrast timing sensitivity for isolated streams of audio and visual speech, and for streams of audio and visual speech accompanied by additional, temporally offset, visual speech streams. We find that the precision with which synchronous streams of audio and visual speech are identified is enhanced by the presence of additional streams of asynchronous visual speech. Our data suggest that timing perception is shaped by selective grouping processes, which can result in enhanced precision in temporally cluttered environments. The imprecision suggested by previous studies might therefore be a consequence of examining isolated pairs of audio and visual events. We argue that when an isolated pair of cross-modal events is presented, they tend to group perceptually and to seem synchronous as a consequence. We have revealed greater precision by providing multiple visual signals, possibly allowing a single auditory speech stream to group selectively with the most synchronous visual candidate. The grouping processes we have identified might be important in daily life, such as when we attempt to follow a conversation in a crowded room.

  6. Bumblebee flight performance in cluttered environments: effects of obstacle orientation, body size and acceleration.

    Science.gov (United States)

    Crall, James D; Ravi, Sridhar; Mountcastle, Andrew M; Combes, Stacey A

    2015-09-01

    Locomotion through structurally complex environments is fundamental to the life history of most flying animals, and the costs associated with movement through clutter have important consequences for the ecology and evolution of volant taxa. However, few studies have directly investigated how flying animals navigate through cluttered environments, or examined which aspects of flight performance are most critical for this challenging task. Here, we examined how body size, acceleration and obstacle orientation affect the flight of bumblebees in an artificial, cluttered environment. Non-steady flight performance is often predicted to decrease with body size, as a result of a presumed reduction in acceleration capacity, but few empirical tests of this hypothesis have been performed in flying animals. We found that increased body size is associated with impaired flight performance (specifically transit time) in cluttered environments, but not with decreased peak accelerations. In addition, previous studies have shown that flying insects can produce higher accelerations along the lateral body axis, suggesting that if maneuvering is constrained by acceleration capacity, insects should perform better when maneuvering around objects laterally rather than vertically. Our data show that bumblebees do generate higher accelerations in the lateral direction, but we found no difference in their ability to pass through obstacle courses requiring lateral versus vertical maneuvering. In sum, our results suggest that acceleration capacity is not a primary determinant of flight performance in clutter, as is often assumed. Rather than being driven by the scaling of acceleration, we show that the reduced flight performance of larger bees in cluttered environments is driven by the allometry of both path sinuosity and mean flight speed. Specifically, differences in collision-avoidance behavior underlie much of the variation in flight performance across body size, with larger bees

  7. Comparative analyses of different variants of standard ground for automatic control systems of technical processes of oil and gas production

    Science.gov (United States)

    Gromakov, E. I.; Gazizov, A. T.; Lukin, V. P.; Chimrov, A. V.

    2017-01-01

    The paper analyses efficiency (interference resistance) of standard TT, TN, IT networks in control links of automatic control systems (ACS) of technical processes (TP) of oil and gas production. Electromagnetic compatibility (EMC) is a standard term used to describe the interference in grounding circuits. Improved EMC of ACS TP can significantly reduce risks and costs of malfunction of equipment that could have serious consequences. It has been proved that an IT network is the best type of grounds for protection of ACS TP in real life conditions. It allows reducing the interference down to the level that is stated in standards of oil and gas companies.

  8. Detecting and mitigating wind turbine clutter for airspace radar systems.

    Science.gov (United States)

    Wang, Wen-Qin

    2013-01-01

    It is well recognized that a wind turbine has a large radar cross-section (RCS) and, due to the movement of the blades, the wind turbine will generate a Doppler frequency shift. This scattering behavior may cause severe interferences on existing radar systems including static ground-based radars and spaceborne or airborne radars. To resolve this problem, efficient techniques or algorithms should be developed to mitigate the effects of wind farms on radars. Herein, one transponder-based mitigation technique is presented. The transponder is not a new concept, which has been proposed for calibrating high-resolution imaging radars. It modulates the radar signal in a manner that the retransmitted signals can be separated from the scene echoes. As wind farms often occupy only a small area, mitigation processing in the whole radar operation will be redundant and cost inefficient. Hence, this paper uses a transponder to determine whether the radar is impacted by the wind farms. If so, the effects of wind farms are then mitigated with subsequent Kalman filtering or plot target extraction algorithms. Taking airborne synthetic aperture radar (SAR) and pulse Doppler radar as the examples, this paper provides the corresponding system configuration and processing algorithms. The effectiveness of the mitigation technique is validated by numerical simulation results.

  9. Parametric Coding of the Size and Clutter of Natural Scenes in the Human Brain.

    Science.gov (United States)

    Park, Soojin; Konkle, Talia; Oliva, Aude

    2015-07-01

    Estimating the size of a space and its degree of clutter are effortless and ubiquitous tasks of moving agents in a natural environment. Here, we examine how regions along the occipital-temporal lobe respond to pictures of indoor real-world scenes that parametrically vary in their physical "size" (the spatial extent of a space bounded by walls) and functional "clutter" (the organization and quantity of objects that fill up the space). Using a linear regression model on multivoxel pattern activity across regions of interest, we find evidence that both properties of size and clutter are represented in the patterns of parahippocampal cortex, while the retrosplenial cortex activity patterns are predominantly sensitive to the size of a space, rather than the degree of clutter. Parametric whole-brain analyses confirmed these results. Importantly, this size and clutter information was represented in a way that generalized across different semantic categories. These data provide support for a property-based representation of spaces, distributed across multiple scene-selective regions of the cerebral cortex.

  10. Settlement process of radioactive dust to the ground inferred from the atmospheric electric field measurement

    Directory of Open Access Journals (Sweden)

    M. Yamauchi

    2012-01-01

    Full Text Available Radioactive materials from the accident at Fukushima Dai-ichi nuclear power plant (FNPP in March 2011 spread over a large area, increasing the atmospheric electric conductivity by their ionizing effect, and reducing the vertical (downward component of the DC electric field near the ground, or potential gradient (PG. PG data at Kakioka, 150 km away from the FNPP, showed independent changes compared to the radiation dose rate, and a comparison of these data revealed the local dynamics of the radioactive dust.

    (1 The initial drop of the PG to almost zero during 14–15 March is most likely due to radioactive dust suspended in the air near the ground during cloudy weather. (2 An episode of PG increase to more than 50 V m−1 on 16 March is most likely due to the re-suspension of the radioactive dust from the surface and subsequent removal from Kakioka by the strong wind from the non-contaminated area. (3 Low but finite values of the PG during 16–20 March most likely reflect a reduced amount of radioactive material near the ground after the above wind transported away the majority of the suspended radioactive dust. (4 Very low values of the PG after substantial rain on 20–22 March most likely reflect settlement of the radioactive material by rain-induced fallout. (5 Temporal recovery of daily variations from the end of March to the middle of April with low nighttime fair-weather baseline PG most likely reflects re-suspension of the radioactive dust into the air from the ground and trees, and subsequent transport to the other region or fallout to the ground until late April. (6 Weakening of the daily variation and gradual recovery of the nighttime fair-weather baseline after mid-April suggests a complete settlement of the radioactive material to the ground with partial migration to the subsurface.

  11. Settlement process of radioactive dust to the ground inferred from the atmospheric electric field measurement

    Energy Technology Data Exchange (ETDEWEB)

    Yamauchi, M. [Swedish Institute of Space Physics, Kiruna (Sweden); Takeda, M. [Kyoto Univ. (Japan). Data Analysis Center for Geomagnetism and Space Magnetism; Makino, M.; Miyagi, I. [National Institute of Advanced Industrial Science and Technology, Tsukuba (Japan); Owada, T. [Japan Meteorological Agency, Ishioka (Japan). Kakioka Magnetic Observatory

    2012-07-01

    Radioactive materials from the accident at Fukushima Dai-ichi nuclear power plant (FNPP) in March 2011 spread over a large area, increasing the atmospheric electric conductivity by their ionizing effect, and reducing the vertical (downward) component of the DC electric field near the ground, or potential gradient (PG). PG data at Kakioka, 150 km away from the FNPP, showed independent changes compared to the radiation dose rate, and a comparison of these data revealed the local dynamics of the radioactive dust. (1) The initial drop of the PG to almost zero during 14-15 March is most likely due to radioactive dust suspended in the air near the ground during cloudy weather. (2) An episode of PG increase to more than 50Vm{sup -1} on 16 March is most likely due to the re-suspension of the radioactive dust from the surface and subsequent removal from Kakioka by the strong wind from the non-contaminated area. (3) Low but finite values of the PG during 16-20 March most likely reflect a reduced amount of radioactive material near the ground after the above wind transported away the majority of the suspended radioactive dust. (4) Very low values of the PG after substantial rain on 20-22 March most likely reflect settlement of the radioactive material by rain-induced fallout. (5) Temporal recovery of daily variations from the end of March to the middle of April with low nighttime fair-weather baseline PG most likely reflects re-suspension of the radioactive dust into the air from the ground and trees, and subsequent transport to the other region or fallout to the ground until late April. (6) Weakening of the daily variation and gradual recovery of the nighttime fair-weather baseline after mid-April suggests a complete settlement of the radioactive material to the ground with partial migration to the subsurface. (orig.)

  12. Settlement process of radioactive dust to the ground inferred from the atmospheric electric field measurement

    Science.gov (United States)

    Yamauchi, M.; Takeda, M.; Makino, M.; Owada, T.; Miyagi, I.

    2012-01-01

    Radioactive materials from the accident at Fukushima Dai-ichi nuclear power plant (FNPP) in March 2011 spread over a large area, increasing the atmospheric electric conductivity by their ionizing effect, and reducing the vertical (downward) component of the DC electric field near the ground, or potential gradient (PG). PG data at Kakioka, 150 km away from the FNPP, showed independent changes compared to the radiation dose rate, and a comparison of these data revealed the local dynamics of the radioactive dust. (1) The initial drop of the PG to almost zero during 14-15 March is most likely due to radioactive dust suspended in the air near the ground during cloudy weather. (2) An episode of PG increase to more than 50 V m-1 on 16 March is most likely due to the re-suspension of the radioactive dust from the surface and subsequent removal from Kakioka by the strong wind from the non-contaminated area. (3) Low but finite values of the PG during 16-20 March most likely reflect a reduced amount of radioactive material near the ground after the above wind transported away the majority of the suspended radioactive dust. (4) Very low values of the PG after substantial rain on 20-22 March most likely reflect settlement of the radioactive material by rain-induced fallout. (5) Temporal recovery of daily variations from the end of March to the middle of April with low nighttime fair-weather baseline PG most likely reflects re-suspension of the radioactive dust into the air from the ground and trees, and subsequent transport to the other region or fallout to the ground until late April. (6) Weakening of the daily variation and gradual recovery of the nighttime fair-weather baseline after mid-April suggests a complete settlement of the radioactive material to the ground with partial migration to the subsurface.

  13. Rule-Driven Object Tracking in Clutter and Partial Occlusion with Model-Based Snakes

    Directory of Open Access Journals (Sweden)

    Rapantzikos Konstantinos

    2004-01-01

    Full Text Available In the last few years it has been made clear to the research community that further improvements in classic approaches for solving low-level computer vision and image/video understanding tasks are difficult to obtain. New approaches started evolving, employing knowledge-based processing, though transforming a priori knowledge to low-level models and rules are far from being straightforward. In this paper, we examine one of the most popular active contour models, snakes, and propose a snake model, modifying terms and introducing a model-based one that eliminates basic problems through the usage of prior shape knowledge in the model. A probabilistic rule-driven utilization of the proposed model follows, being able to handle (or cope with objects of different shapes, contour complexities and motions; different environments, indoor and outdoor; cluttered sequences; and cases where background is complex (not smooth and when moving objects get partially occluded. The proposed method has been tested in a variety of sequences and the experimental results verify its efficiency.

  14. Circular economy in drinking water treatment: reuse of ground pellets as seeding material in the pellet softening process.

    Science.gov (United States)

    Schetters, M J A; van der Hoek, J P; Kramer, O J I; Kors, L J; Palmen, L J; Hofs, B; Koppers, H

    2015-01-01

    Calcium carbonate pellets are produced as a by-product in the pellet softening process. In the Netherlands, these pellets are applied as a raw material in several industrial and agricultural processes. The sand grain inside the pellet hinders the application in some high-potential market segments such as paper and glass. Substitution of the sand grain with a calcite grain (100% calcium carbonate) is in principle possible, and could significantly improve the pellet quality. In this study, the grinding and sieving of pellets, and the subsequent reuse as seeding material in pellet softening were tested with two pilot reactors in parallel. In one reactor, garnet sand was used as seeding material, in the other ground calcite. Garnet sand and ground calcite performed equally well. An economic comparison and a life-cycle assessment were made as well. The results show that the reuse of ground calcite as seeding material in pellet softening is technologically possible, reduces the operational costs by €38,000 (1%) and reduces the environmental impact by 5%. Therefore, at the drinking water facility, Weesperkarspel of Waternet, the transition from garnet sand to ground calcite will be made at full scale, based on this pilot plant research.

  15. Effect of boiling water carcass immersion on aerobic bacteria counts of poultry skin and processed ground poultry meat.

    Science.gov (United States)

    Tompkins, N M; Avens, J S; Kendall, P A; Salman, M D

    2008-06-01

    This study was conducted to determine the relationship between bacteria destruction on poultry carcass skin and bacteria in raw ground poultry meat from the same carcasses. Immersion time in boiling water of broiler chicken whole carcasses required for maximum reduction of naturally occurring aerobic bacterial count on skin was measured. Treatments for chicken carcasses consisted of immersion in boiling water (approximately 95 degrees C) for 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, and 4 min. Four skin samples taken following treatment and three taken from subsequently ground carcass meat were analyzed for total aerobic plate counts (APC). Analysis of the data indicated a linear increase in bacterial destruction on skin with increased boiling water immersion time from 0 to 4 min. Reduction of skin bacteria to less than 1 log10 occurred at 3 min carcass immersion or longer. The analysis also indicated that treatment with boiling water and removal of skin was effective in reducing bacterial counts in ground meat to similar levels at all treatment times from 0.5 to 4.0 min. Findings from this study indicated that a boiling water immersion intervention and removal of skin could reduce subsequent bacteria contamination of ground meat. This intervention could minimize the risk of pathogen-contaminated primary processed poultry carcasses used in further processing.

  16. How human resource organization can enhance space information acquisition and processing: the experience of the VENESAT-1 ground segment

    Science.gov (United States)

    Acevedo, Romina; Orihuela, Nuris; Blanco, Rafael; Varela, Francisco; Camacho, Enrique; Urbina, Marianela; Aponte, Luis Gabriel; Vallenilla, Leopoldo; Acuña, Liana; Becerra, Roberto; Tabare, Terepaima; Recaredo, Erica

    2009-12-01

    Built in cooperation with the P.R of China, in October 29th of 2008, the Bolivarian Republic of Venezuela launched its first Telecommunication Satellite, the so called VENESAT-1 (Simón Bolívar Satellite), which operates in C (covering Center America, The Caribbean Region and most of South America), Ku (Bolivia, Cuba, Dominican Republic, Haiti, Paraguay, Uruguay, Venezuela) and Ka bands (Venezuela). The launch of VENESAT-1 represents the starting point for Venezuela as an active player in the field of space science and technology. In order to fulfill mission requirements and to guarantee the satellite's health, local professionals must provide continuous monitoring, orbit calculation, maneuvers preparation and execution, data preparation and processing, as well as data base management at the VENESAT-1 Ground Segment, which includes both a primary and backup site. In summary, data processing and real time data management are part of the daily activities performed by the personnel at the ground segment. Using published and unpublished information, this paper presents how human resource organization can enhance space information acquisition and processing, by analyzing the proposed organizational structure for the VENESAT-1 Ground Segment. We have found that the proposed units within the organizational structure reflect 3 key issues for mission management: Satellite Operations, Ground Operations, and Site Maintenance. The proposed organization is simple (3 hierarchical levels and 7 units), and communication channels seem efficient in terms of facilitating information acquisition, processing, storage, flow and exchange. Furthermore, the proposal includes a manual containing the full description of personnel responsibilities and profile, which efficiently allocates the management and operation of key software for satellite operation such as the Real-time Data Transaction Software (RDTS), Data Management Software (DMS), and Carrier Spectrum Monitoring Software (CSM

  17. Background Noise Distribution before and afterHigh-Resolution Processing in Ship-borne Radar

    Institute of Scientific and Technical Information of China (English)

    ZHANGZhong

    2005-01-01

    When high-resolution algorithm is applied in ship-borne radar~ high-resolution algorithm's nonlinearity and distributional characteristics before highresolution processing determine background clutter's distributional characteristics after high-resolution and detector design afterwards. Because background noise before high-resolution has physical significance, the statistical model of first-order Bragg lines and second order components of sea clutter is put forward. Then by using higher-order cumulative quantity's statistical verification of actually measured data, it is concluded that background noise before high-resolution conforms to normal distribution in ship-borne radar. The non-linearity of high-resolution algorithm determines that background noise after high-resolution processing conforms to non-normal distribution. Non-normal distributed clutter mainly include Weibull, Lognormal and K clutter. Rayleigh clutter can be seen as special case of Weibull clutter. These clutter have differently statistical characteristics and can be discriminated by clutter characteristics recognition. The numerical domain's distribution after high-resolution processing is determined by improved minimum entropy clutter characteristics recognition method based on rule AIC, namely two-parameter domain scanning method. This identification method has higher recognition rate. It is verified that background noise after high-resolution by pre-whitenedMUSIC conforms to lognormal distribution.

  18. Using particle filter to track horizontal variations of atmospheric duct structure from radar sea clutter

    Directory of Open Access Journals (Sweden)

    X. F. Zhao

    2012-08-01

    Full Text Available This paper addresses the problem of estimating range-varying parameters of the height-dependent refractivity over the sea surface from radar sea clutter. In the forward simulation, the split-step Fourier parabolic equation (PE is used to compute the radar clutter power in the complex refractive environments. Making use of the inherent Markovian structure of the split-step Fourier PE solution, the refractivity from clutter (RFC problem is formulated within a nonlinear recursive Bayesian state estimation framework. Particle filter (PF that is a technique for implementing a recursive Bayesian filter by Monte Carlo simulations is used to track range-varying characteristics of the refractivity profiles. Basic ideas of employing PF to solve RFC problem are introduced. Both simulation and real data results are presented to check up the feasibility of PF-RFC performances.

  19. Photoacoustic clutter reduction by inversion of a linear scatter model using plane wave ultrasound measurements.

    Science.gov (United States)

    Schwab, Hans-Martin; Beckmann, Martin F; Schmitz, Georg

    2016-04-01

    Photoacoustic imaging aims to visualize light absorption properties of biological tissue by receiving a sound wave that is generated inside the observed object as a result of the photoacoustic effect. In clinical applications, the strong light absorption in human skin is a major problem. When high amplitude photoacoustic waves that originate from skin absorption propagate into the tissue, they are reflected back by acoustical scatterers and the reflections contribute to the received signal. The artifacts associated with these reflected waves are referred to as clutter or skin echo and limit the applicability of photoacoustic imaging for medical applications severely. This study seeks to exploit the acoustic tissue information gained by plane wave ultrasound measurements with a linear array in order to correct for reflections in the photoacoustic image. By deriving a theory for clutter waves in k-space and a matching inversion approach, photoacoustic measurements compensated for clutter are shown to be recovered.

  20. Statistical-physical model for foliage clutter in ultra-wideband synthetic aperture radar images.

    Science.gov (United States)

    Banerjee, Amit; Chellappa, Rama

    2003-01-01

    Analyzing foliage-penetrating (FOPEN) ultra-wideband synthetic aperture radar (SAR) images is a challenging problem owing to the noisy and impulsive nature of foliage clutter. Indeed, many target-detection algorithms for FOPEN SAR data are characterized by high false-alarm rates. In this work, a statistical-physical model for foliage clutter is proposed that explains the presence of outliers in the data and suggests the use of symmetric alpha-stable (SalphaS) distributions for accurate clutter modeling. Furthermore, with the use of general assumptions of the noise sources and propagation conditions, the proposed model relates the parameters of the SalphaS model to physical parameters such as the attenuation coefficient and foliage density.

  1. Impact of atmospheric clutter on Doppler-limited gas sensors in the submillimeter/terahertz.

    Science.gov (United States)

    Medvedev, Ivan R; Neese, Christopher F; Plummer, Grant M; De Lucia, Frank C

    2011-06-20

    It is well known that clutter (spectral interference) from atmospheric constituents can be a severe limit for spectroscopic point sensors, especially where high sensitivity and specificity are required. In this paper, we will show for submillimeter/terahertz (SMM/THz) sensors that use cw electronic techniques the clutter limit for the detection of common target gases with absolute specificity (probability of false alarm ≪ 10⁻¹⁰) is in the ppt (1 part in 10¹²) range or lower. This is because the most abundant atmospheric gases are either transparent to SMM/THz radiation (e.g., CO₂) or have spectra that are very sparse relative to the 10⁵ Doppler-limited resolution elements available (e.g., H₂O). Moreover, the low clutter limit demonstrated for cw electronic systems in the SMM/THz is independent of system size and complexity.

  2. Simulation and Prediction of Weather Radar Clutter Using a Wave Propagator on High Resolution NWP Data

    DEFF Research Database (Denmark)

    Benzon, Hans-Henrik; Bovith, Thomas

    2008-01-01

    for prediction of this type of weather radar clutter is presented. The method uses a wave propagator to identify areas of potential non-standard propagation. The wave propagator uses a three dimensional refractivity field derived from the geophysical parameters: temperature, humidity, and pressure obtained from...... a high-resolution Numerical Weather Prediction (NWP) model. The wave propagator is based on the parabolic equation approximation to the electromagnetic wave equation. The parabolic equation is solved using the well-known Fourier split-step method. Finally, the radar clutter prediction technique is used......Weather radars are essential sensors for observation of precipitation in the troposphere and play a major part in weather forecasting and hydrological modelling. Clutter caused by non-standard wave propagation is a common problem in weather radar applications, and in this paper a method...

  3. Trawling bats exploit an echo-acoustic ground effect

    Directory of Open Access Journals (Sweden)

    Sandor eZsebok

    2013-04-01

    Full Text Available A water surface acts not only as an optic mirror but also as an acoustic mirror. Echolocation calls emitted by bats at low heights above water are reflected away from the bat, and hence the background clutter is reduced. Moreover, targets on the surface create an enhanced echo. Here, we formally quantified the effect of the substrate and target height on both target detection and –discrimination in a combined laboratory and field approach with Myotis daubentonii. In a two-alternative, forced-choice paradigm, the bats had to detect a mealworm and discriminate it from an inedible dummy (20 mm PVC disc. Psychophysical performance was measured as a function of height above either smooth substrates (water or PVC or above a clutter substrate (artificial grass. At low heights above the clutter substrate (10, 20 or 35 cm, the bats’ detection performance was worse than above a smooth substrate. At a height of 50 cm, the substrate structure had no influence on target detection. Above the clutter surface, also target discrimination was significantly impaired with decreasing target height. A detailed analysis of the bats’ echolocation calls during target approach shows that above the clutter substrate, the bats produce calls with significantly higher peak frequency. Flight-path reconstruction revealed that the bats attacked an object from below over water but from above over a clutter substrate.These results are consistent with the hypothesis that trawling bats exploit an echo-acoustic ground effect, in terms of a spatio-temporal integration of direct reflections with indirect reflections from the water surface, to optimize prey detection and –discrimination not only for prey on the water but also for some range above.

  4. Trawling bats exploit an echo-acoustic ground effect.

    Science.gov (United States)

    Zsebok, Sandor; Kroll, Ferdinand; Heinrich, Melina; Genzel, Daria; Siemers, Björn M; Wiegrebe, Lutz

    2013-01-01

    A water surface acts not only as an optic mirror but also as an acoustic mirror. Echolocation calls emitted by bats at low heights above water are reflected away from the bat, and hence the background clutter is reduced. Moreover, targets on the surface create an enhanced echo. Here, we formally quantified the effect of the surface and target height on both target detection and -discrimination in a combined laboratory and field approach with Myotis daubentonii. In a two-alternative, forced-choice paradigm, the bats had to detect a mealworm and discriminate it from an inedible dummy (20 mm PVC disc). Psychophysical performance was measured as a function of height above either smooth surfaces (water or PVC) or above a clutter surface (artificial grass). At low heights above the clutter surface (10, 20, or 35 cm), the bats' detection performance was worse than above a smooth surface. At a height of 50 cm, the surface structure had no influence on target detection. Above the clutter surface, also target discrimination was significantly impaired with decreasing target height. A detailed analysis of the bats' echolocation calls during target approach shows that above the clutter surface, the bats produce calls with significantly higher peak frequency. Flight-path reconstruction revealed that the bats attacked an target from below over water but from above over a clutter surface. These results are consistent with the hypothesis that trawling bats exploit an echo-acoustic ground effect, in terms of a spatio-temporal integration of direct reflections with indirect reflections from the water surface, to optimize prey detection and -discrimination not only for prey on the water but also for some range above.

  5. Advancing Nursing Research in the Visual Era: Reenvisioning the Photovoice Process Across Phenomenological, Grounded Theory, and Critical Theory Methodologies.

    Science.gov (United States)

    Evans-Agnew, Robin A; Boutain, Doris M; Rosemberg, Marie-Anne S

    Photovoice is a powerful research method that employs participant photography for advancing voice, knowledge, and transformative change among groups historically or currently marginalized. Paradoxically, this research method risks exploitation of participant voice because of weak methodology to method congruence. The purposes of this retrospective article are to revisit current interdisciplinary research using photovoice and to suggest how to advance photovoice by improving methodology-method congruence. Novel templates are provided for improving the photovoice process across phenomenological, grounded theory, and critical theory methodologies.

  6. Precipitation and microphysical processes observed by three polarimetric X-band radars and ground-based instrumentation during HOPE

    OpenAIRE

    Xie, Xinxin; Evaristo, Raquel; Simmer, Clemens; Handwerker, Jan; Trömel, Silke

    2016-01-01

    This study presents a first analysis of precipitation and related microphysical processes observed by three polarimetric X-band Doppler radars (BoXPol, JuXPol and KiXPol) in conjunction with a ground-based network of disdrometers, rain gauges and vertically pointing micro rain radars (MRRs) during the High Definition Clouds and Precipitation for advancing Climate Prediction (HD(CP)2) Observational Prototype Experiment (HOPE) during April and May 2013 in Germany. While JuXPol...

  7. Visual Multi-Object Tracking in the Presence of Cluttered Scenes

    Directory of Open Access Journals (Sweden)

    Xu-Sheng Gan

    2013-07-01

    Full Text Available The aim of this study was to investigate the visual multi-object tracking in the presence of cluttered scenes. A improved algorithm of fusing multi-source information including location and color evidences were introduced based on Dezert-Smarandache Theory (DSmT and Particle Filters (PF. Results showed that the conflict strategy and DSmT combination model were available and the proposed approach exhibited a significantly better performance for dealing with high conflict between evidences than a conventional PF. The suggested approach can easily be generalized to deal with larger number of visual multi-object and additional cues in the presence of cluttered scenes.

  8. Direction-of-Arrival Estimation for Radar Ice Sounding Surface Clutter Suppression

    DEFF Research Database (Denmark)

    Nielsen, Ulrik; Dall, Jørgen

    2015-01-01

    Ice sounding radars are able to measure ice sheets by profiling their glaciological features from the surface to the bedrock. The current airborne and, in particular, future space-based systems are suffering from off-nadir surface clutter, which can mask the depth signal of interest. The most...... estimation for surface clutter signals, which includes a formulation of the mathematical foundation of spatial aliasing. DOA estimation is applied to data acquired with the P-band POLarimetric Airborne Radar Ice Sounder at the Jutulstraumen Glacier, Antarctica. The effects of spatial aliasing related...

  9. Numerical simulation of radar surveillance for the ship target in oceanic clutters

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A fast iterative approach of generalized forward-backward method with the spectrum acceleration algorithm (GFBM/SAA) is developed for solving electromagnetic field integral equation and is applied to numerical simulation of radar surveillance of the ship target in oceanic clutters. Randomly rough surface is realized by the Monte Carlo method using the Pierson-Moskowitz spectrum. Numerical results of bistatic and back-scattering from the ship target and oceanic clutters demonstrate the functional dependencies upon the situation of radar surveillance such as the incidence and observation angles, radar altitude, ship RCS and other oceanic conditions.

  10. Inactivation of a diverse set of shiga toxin-producing Escherichia coli in ground beef by high pressure processing.

    Science.gov (United States)

    Sheen, Shiowshuh; Cassidy, Jennifer; Scullen, Butch; Sommers, Christopher

    2015-12-01

    Shiga toxin-producing Escherichia coli (STEC) are regularly implicated in foodborne illness outbreaks and recalls of ground beef. In this study we determined the High Pressure Processing (HPP) D10 value (the processing conditions needed to reduce the microbial population by 1 log) of 39 STEC isolates, including the "big six" serovars, O104 and O157:H7. STEC isolates included those isolated from animals and environmental sources in addition to those associated with illness in humans. Individual STEC were inoculated into 80% lean ground beef and treated with HPP (350 MPa, 4 °C, up to 40 min). The mean D10 was 9.74 min, with a range of 0.89-25.70 min. The D10 of the STEC involved in human illness was 9.25 vs. 10.40 min for those not involved in human illness (p > 0.05). The presence or absence of genes encoding virulence factors (e.g. Shiga toxin 1 or 2, intimin, or enterohemolysin) had no effect on the HPP D10 (p > 0.05). The high D10 of some STEC involved in human illness should be considered in selecting HPP processing parameters for ground beef. This study demonstrates the heterogeneity of STEC resistance to HPP. Risk assessors and the food industry can use this information to provide safer meat products to consumers.

  11. Finite Element Optimization for Nondestructive Evaluation on a Graphics Processing Unit for Ground Vehicle Hull Inspection

    Science.gov (United States)

    2013-08-22

    GPU ,GA, genetic algorithm, FE, optimization, CUDA , Damage, Evaluation 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF... GPU with CUDA architecture [4]). There is however a severe memory limit – 4 GB at present. This would limit large problems as well as optimization...August 2013 UNCLASSIFIED UNCLASSIFIED Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 FE Optimization for NDE on GPUs for Ground

  12. Modeling of Rocket Fuel Heating and Cooling Processes in the Interior Receptacle Space of Ground-Based Systems

    Directory of Open Access Journals (Sweden)

    K. I. Denisova

    2016-01-01

    Full Text Available The propellant to fill the fuel tanks of the spacecraft, upper stages, and space rockets on technical and ground-based launch sites before fueling should be prepared to ensure many of its parameters, including temperature, in appropriate condition. Preparation of fuel temperature is arranged through heating and cooling the rocket propellants (RP in the tanks of fueling equipment. Processes of RP temperature preparation are the most energy-intensive and timeconsuming ones, which require that a choice of sustainable technologies and modes of cooling (heating RP provided by the ground-based equipment has been made through modeling of the RP [1] temperature preparation processes at the stage of design and operation of the groundbased fueling equipment.The RP temperature preparation in the tanks of the ground-based systems can be provided through the heat-exchangers built-in the internal space and being external with respect to the tank in which antifreeze, air or liquid nitrogen may be used as the heat transfer media. The papers [1-12], which note a promising use of the liquid nitrogen to cool PR, present schematic diagrams and modeling systems for the RP temperature preparation in the fueling equipment of the ground-based systems.We consider the RP temperature preparation using heat exchangers to be placed directly in RP tanks. Feeding the liquid nitrogen into heat exchanger with the antifreeze provides the cooling mode of PR while a heated air fed there does that of heating. The paper gives the systems of equations and results of modeling the processes of RP temperature preparation, and its estimated efficiency.The systems of equations of cooling and heating RP are derived on the assumption that the heat exchange between the fuel and the antifreeze, as well as between the storage tank and the environment is quasi-stationary.The paper presents calculation results of the fuel temperature in the tank, and coolant temperature in the heat exchanger, as

  13. Wall Clutter Mitigation in Through-the-Wall Imaging Radar with Sparse Array Antenna Based on Independent Component Analysis

    Directory of Open Access Journals (Sweden)

    Zhang Chi

    2014-10-01

    Full Text Available For Through-the-Wall Imaging Radar (TWIR, wall clutter is critical for detecting target signals behind a wall. For a system with a sparse antenna array, the lack of observation channels makes it more difficult to separate the target signals and wall clutter. On the basis of fluctuation of the range profile in real transmit/receive channels, this paper proposes to use Independent Component Analysis (ICA on multiple down-range observations of each transmit/receive channel to remove the wall clutter. The simulation and experimental results show that the proposed method effectively separate target and clutter components, even though the signal-to-clutter ratio is only -30 dB.

  14. Advancement of High Resolution Radar Polarimetry in Target Verses Clutter Detection, Discrimination, Classification: A. Basic Theory and Modeling of Polarimetric Clutter Phenomenology.

    Science.gov (United States)

    1988-07-15

    Humboldt award, and another 15,000 km by train (during the tough winter months 1987 Jan.-March) and airplane (from Noordkap to Lisbon, from Weston -Super...polarLmetry to target/clutter analysis was recognized Kannen (11 with deletions and addition to meet his- long ago. w. also note here that Copeland (1960...8217. 1960 Copeland classifies (syimnetrical) radar 1975 Poelman reports on using orthoonally targets by polarization properties. polarized returns to detect

  15. Ground-water quality and geochemical processes at a municipal landfill, Town of Brookhaven, Long Island, New York

    Science.gov (United States)

    Pearsall, Kenneth A.; Aufderheide, Mary Jean

    1995-01-01

    The principal geochemical process within a plume of leachate-contaminated ground water downgradient from the municipal landfill in the Town of Brookhaven is the oxidation of organic matter. Concurrent reducing processes are the reduction of iron and manganese oxyhydroxides to soluble ferrous and manganous forms, of nitrate and nitrite to nitrogen and ammonia, of sulfate to sulfide (sulfide precipitates from solution as iron and manganese sulfides), and, under extreme conditions, of some organic matter to methane. Secondary processes unrelated to bacterial activity and redox processes are the exchange of dissolved sodium and potassium for calcium and magnesium at ion-exchange sites and the dissolution of calcium and magnesium silicate minerals; these processes cause sodium and potassium concentrations to decrease with depth and with distance from the landfill and cause calcium, magnesium, and silica concentrations to increase.

  16. Mine detection with a forward-looking ground-penetrating synthetic aperture radar

    Science.gov (United States)

    Bradley, Marshall R.; Witten, Thomas R.; Duncan, Michael; McCummins, Robert

    2003-09-01

    In order to detect buried land mines in clutter, Planning Systems Incorporated has adapted its Ground Penetrating Synthetic Aperture Radar (GPSAR) technology for forward-looking applications. The Forward Looking GPSAR (FLGPSAR), is a wide-band stepped-frequency radar operating over frequencies from 400 MHz to 4 GHz. The FLGPSAR system is based on a modified John Deere E-Gator turf vehicle that is capable of remote control. Custom Archimedean spiral antennas are used to populate the GPSAR array. These antennas are designed and built by PSI and have exceptional broad-band radiation characteristics. The FLGSPAR system has been used to detect plastic and metallic landmines at U.S. Army test facilities and at PSI's engineering center in Long Beach Mississippi. Multi-look SAR processing has been shown to significantly improve the quality of FLGPSAR imagery.

  17. Becoming Therapeutic Agents: A Grounded Theory of Mothers' Process When Implementing Cognitive Behavioural Therapy at Home with an Anxious Child.

    Science.gov (United States)

    Pishva, Rana

    2016-09-29

    The premise of parent-centred programmes for parents of anxious children is to educate and train caregivers in the sustainable implementation of cognitive behaviour therapy (CBT) in the home. The existing operationalization of parent involvement, however, does not address the systemic, parent or child factors that could influence this process. The qualitative approach of grounded theory was employed to examine patterns of action and interaction involved in the complex process of carrying out CBT with one's child in one's home. A grounded theory goes beyond the description of a process, offering an explanatory theory that brings taken-for-granted meanings and processes to the surface. The theory that emerged from the analysis suggests that CBT implementation by mothers of anxious children is characterized by the evolution of mothers' perception of their child and mothers' perception of their role as well as a shift from reacting with emotion to responding pragmatically to the child. Changes occur as mothers recognize the crisis, make links between the treatment rationale, child's symptoms and their own parenting strategies, integrate tenets of CBT for anxiety and eventually focus on sustaining therapeutic gains through natural life transitions. The theory widens our understanding of mothers' role, therapeutic engagement, process, and decision-making. The theory also generates new hypotheses regarding parent involvement in the treatment of paediatric anxiety disorders and proposes novel research avenues that aim to maximize the benefits of parental involvement in the treatment of paediatric anxiety disorders. Copyright © 2016 John Wiley & Sons, Ltd.

  18. Analyzing the transmission structures of long continuing current processes from negative ground flashes on the Qinghai-Tibetan Plateau

    Science.gov (United States)

    Fan, Xiangpeng; Zhang, Guangshu; Wang, Yanhui; Li, Yajun; Zhang, Tong; Wu, Bin

    2014-03-01

    This paper presents a new overlap and progressive method using either a one-point charge model or a point dipole model for studying the electric field change data of lightning and tests the suitability of the proposed method by analyzing the slow electric field change of the long continuing current data from two negative ground flashes. The current measurements of the ground flashes are from the Composite Observing Experiment for Lightning project carried out in the Datong region of Qinghai Province, China, in 2009, obtained from field observations synchronized through high-precision GPS clocks at seven observation stations. Analysis shows that the time-averaged current can reach 800 A, and the current intensity relates to the height of the top of the return stroke before the continuing current process. The two current processes studied in this work neutralized a large amount of negative charge, 39.5C and 60.8C, respectively. The neutralized charges from the negative charge layer are typically at 2.5-4.7 km above ground. The intracloud transition of the positive leader is a complex process, and the horizontal propagation of the positive leader plays an important role in current duration as well as horizontally influencing the center of the electrical dipole moment with an obvious change of up to 3.0 km. The proposed analysis method is very useful compared to previous methods in terms of determining infinitesimal changes in long continuing currents. This work's new analysis method will help increase understanding of the fine physical processes of long continuing current processes.

  19. The SIMCA algorithm for processing Ground Penetrating Radar data and its use in landmine detection

    OpenAIRE

    Sengodan, A.; Cockshott, W. P.

    2012-01-01

    The main challenge of ground penetrating radar (GPR)\\ud based land mine detection is to have an accurate image\\ud analysis method that is capable of reducing false alarms.\\ud However an accurate image relies on having sufficient spatial\\ud resolution in the received signal. But because the diameter\\ud of an AP mine can be as low as 2cm and many soils\\ud have very high attenuations at frequencies above 3GHz,\\ud the accurate detection of landmines is accomplished using\\ud advanced algorithms. U...

  20. Ground-penetrating radar signal processing for the detection of buried objects

    Science.gov (United States)

    Walters, Mitchell; Garcia, Ephrahim

    2011-06-01

    In this work the singular value decomposition (SVD) is used to analyze matrices of ground penetrating radar (GPR) data. The targets to be detected are Russian PMN antipersonnel landmines and improvised explosive devices constructed from 155mm artillery shells. Target responses are simulated with GPRmax 2D, a simulation package based on the Finite- Difference-Time-Domain method. First, the utility of the SVD for image enhancement and reconstruction is demonstrated. Then the singular values and singular vectors of the decomposed matrices are analyzed with the goal of finding properties that will aid in the development of automated underground detection algorithms.

  1. Realtime generation of K-Distributed sea clutter for hardware in the loop radar evaluation

    CSIR Research Space (South Africa)

    Van der Merwe, Johannes R

    2016-10-01

    Full Text Available This paper proposes a practical implementation for the generation of real-time K-Distributed correlated sea-clutter in firmware. The method uses a dual cumulative distribution function (CDF) based look-up method to transpose a complex uniformly...

  2. Breaking through the clutter : Benefits of advertisement originality and familiarity for brand attention and memory

    NARCIS (Netherlands)

    Pieters, R; Warlop, L; Wedel, M

    2002-01-01

    Rising levels of advertising competition have made it increasingly difficult to attract and hold consumers' attention and to establish strong memory traces for the advertised brand. A common communication strategy to break through this competitive clutter is to increase ad originality However, ad or

  3. Breaking through the Advertising Clutter: A Qualitative Analysis of Broken Stereotypes in Print and Television Advertisements.

    Science.gov (United States)

    Larson, Charles U.

    As a result of the overwhelming amount of print and electronic advertisements which compete for consumer attention, advertisers must find effective methods to get through the ad clutter and capture their audience's interest. Several tactics can accomplish this strategy, including the tactic of breaking or reversing audience expectations or…

  4. Moment-Based Physical Models of Broadband Clutter due to Aggregations of Fish

    Science.gov (United States)

    2013-09-30

    their false alarm rate and latency. Accordingly, a quantitative assesment has begun of the temporal persistence of the observed fish-clutter echoes...Assessment of the Pacific Sardine Resource in 2012 for U.S. Management in 2013,” Pacific Fishery Management Council November 2012 Briefing Book

  5. An Improved Clutter Suppression Method for Weather Radars Using Multiple Pulse Repetition Time Technique

    Directory of Open Access Journals (Sweden)

    Yingjie Yu

    2017-01-01

    Full Text Available This paper describes the implementation of an improved clutter suppression method for the multiple pulse repetition time (PRT technique based on simulated radar data. The suppression method is constructed using maximum likelihood methodology in time domain and is called parametric time domain method (PTDM. The procedure relies on the assumption that precipitation and clutter signal spectra follow a Gaussian functional form. The multiple interleaved pulse repetition frequencies (PRFs that are used in this work are set to four PRFs (952, 833, 667, and 513 Hz. Based on radar simulation, it is shown that the new method can provide accurate retrieval of Doppler velocity even in the case of strong clutter contamination. The obtained velocity is nearly unbiased for all the range of Nyquist velocity interval. Also, the performance of the method is illustrated on simulated radar data for plan position indicator (PPI scan. Compared with staggered 2-PRT transmission schemes with PTDM, the proposed method presents better estimation accuracy under certain clutter situations.

  6. A single-ensemble-based hybrid approach to clutter rejection combining bilinear Hankel with regression.

    Science.gov (United States)

    Shen, Zhiyuan; Feng, Naizhang; Lee, Chin-Hui

    2013-04-01

    Clutter regarded as ultrasound Doppler echoes of soft tissue interferes with the primary objective of color flow imaging (CFI): measurement and display of blood flow. Multi-ensemble samples based clutter filters degrade resolution or frame rate of CFI. The prevalent single-ensemble clutter rejection filter is based on a single rejection criterion and fails to achieve a high accuracy for estimating both the low- and high-velocity blood flow components. The Bilinear Hankel-SVD achieved more exact signal decomposition than the conventional Hankel-SVD. Furthermore, the correlation between two arbitrary eigen-components obtained by the B-Hankel-SVD was demonstrated. In the hybrid approach, the input ultrasound Doppler signal first passes through a low-order regression filter, and then the output is properly decomposed into a collection of eigen-components under the framework of B-Hankel-SVD. The blood flow components are finally extracted based on a frequency threshold. In a series of simulations, the proposed B-Hankel-SVD filter reduced the estimation bias of the blood flow over the conventional Hankel-SVD filter. The hybrid algorithm was shown to be more effective than regression or Hankel-SVD filters alone in rejecting the undesirable clutter components with single-ensemble (S-E) samples. It achieved a significant improvement in blood flow frequency estimation and estimation variance over the other competing filters.

  7. Breaking through the clutter : Benefits of advertisement originality and familiarity for brand attention and memory

    NARCIS (Netherlands)

    Pieters, R; Warlop, L; Wedel, M

    2002-01-01

    Rising levels of advertising competition have made it increasingly difficult to attract and hold consumers' attention and to establish strong memory traces for the advertised brand. A common communication strategy to break through this competitive clutter is to increase ad originality However, ad or

  8. Detection of dim point targets in cluttered maritime backgrounds through multisensor image fusion

    NARCIS (Netherlands)

    Toet, A.

    2002-01-01

    Multispectral IR imaging techniques are frequently deployed in maritime operations, for instance to detect floating mines or to find small dinghies and swimmers during search and rescue operations. However, maritime backgrounds usually contain a large amount of clutter that severely hampers the

  9. Detection of dim point targets in cluttered maritime backgrounds through multisensor image fusion

    NARCIS (Netherlands)

    Toet, A.

    2002-01-01

    Multispectral IR imaging techniques are frequently deployed in maritime operations, for instance to detect floating mines or to find small dinghies and swimmers during search and rescue operations. However, maritime backgrounds usually contain a large amount of clutter that severely hampers the dete

  10. Breaking through the clutter : Benefits of advertisement originality and familiarity for brand attention and memory

    NARCIS (Netherlands)

    Pieters, R; Warlop, L; Wedel, M

    Rising levels of advertising competition have made it increasingly difficult to attract and hold consumers' attention and to establish strong memory traces for the advertised brand. A common communication strategy to break through this competitive clutter is to increase ad originality However, ad

  11. Design for human factors (DfHF): a grounded theory for integrating human factors into production design processes.

    Science.gov (United States)

    Village, Judy; Searcy, Cory; Salustri, Filipo; Patrick Neumann, W

    2015-01-01

    The 'design for human factors' grounded theory explains 'how' human factors (HF) went from a reactive, after-injury programme in safety, to being proactively integrated into each step of the production design process. In this longitudinal case study collaboration with engineers and HF Specialists in a large electronics manufacturer, qualitative data (e.g. meetings, interviews, observations and reflections) were analysed using a grounded theory methodology. The central tenet in the theory is that when HF Specialists acclimated to the engineering process, language and tools, and strategically aligned HF to the design and business goals of the organisation, HF became a means to improve business performance. This led to engineers 'pulling' HF Specialists onto their team. HF targets were adopted into engineering tools to communicate HF concerns quantitatively, drive continuous improvement, visibly demonstrate change and lead to benchmarking. Senior management held engineers accountable for HF as a key performance indicator, thus integrating HF into the production design process. Practitioner Summary: Research and practice lack explanations about how HF can be integrated early in design of production systems. This three-year case study and the theory derived demonstrate how ergonomists changed their focus to align with design and business goals to integrate HF into the design process.

  12. Upscaling of a Batch De-Vulcanization Process for Ground Car Tire Rubber to a Continuous Process in a Twin Screw Extruder

    Directory of Open Access Journals (Sweden)

    Sitisaiyidah Saiwari

    2016-08-01

    Full Text Available As a means to decrease the amount of waste tires and to re-use tire rubber for new tires, devulcanization of ground passenger car tires is a promising process. Being an established process for NR and EPDM, earlier work has shown that for ground passenger car tire rubber with a relatively high amount of SBR, a devulcanization process can be formulated, as well. This was proven for a laboratory-scale batch process in an internal mixer, using diphenyl disulfide as the devulcanization aid and powder-sized material. In this paper, the devulcanization process for passenger car tire rubber is upscaled from 15 g per batch and transformed into a continuous process in a co-rotating twin screw extruder with a capacity of 2 kg/h. As SBR is rather sensitive to devulcanization process conditions, such as thermal and mechanical energy input, the screw design was based on a low shear concept. A granulate with particle sizes from 1–3.5 mm was chosen for purity, as well as economic reasons. The devulcanization process conditions were fine-tuned in terms of: devulcanization conditions (time/temperature profile, concentration of devulcanization aid, extruder parameters (screw configuration, screw speed, fill factor and ancillary equipment (pre-treatment, extrudate handling. The influence of these parameters on the devulcanization efficiency and the quality of the final product will be discussed. The ratio of random to crosslink scission as determined by a Horikx plot was taken for the evaluation of the process and material. A best practice for continuous devulcanization will be given.

  13. Programme notes. 36th IPA Congress, Rome, 1989. The search for common ground: clinical aims and processes.

    Science.gov (United States)

    Richards, A D

    1991-01-01

    This paper presents a summary and an overview of the 36th IPA Congress, 'Common ground in psychoanalysis: clinical aims and processes'. The theme emerged from Dr Robert Wallerstein's 1987 Montreal Congress Plenary Address, 'One psychoanalysis or many'. The paper focuses on the three Rome Plenary presentations and their discussions, Wallerstein's presidential address, and the final panel review. A paper presented at the meeting by Charles Hanly, 'The concept of truth in psychoanalysis', which outlines theories of truth: correspondence versus coherence, provides the conceptual tools for considering the different points of view. The author shares Hanly's support for a pragmatically qualified commitment to a correspondence theory of truth.

  14. Inactivation of Salmonella spp. in ground chicken using High Pressure Processing

    Science.gov (United States)

    High pressure processing (HPP) is a safe and effective process for improving the microbial safety and shelf-life of foods. Salmonella is a common contaminant in poultry meat and is frequently responsible for foodborne illness associated with contaminated poultry meat. In this study the inactivation...

  15. How parents process child health and nutrition information: A grounded theory model.

    Science.gov (United States)

    Lovell, Jennifer L

    2016-02-01

    The aim of the present study was to investigate low-income parents' experiences receiving, making meaning of, and applying sociocultural messages about childhood health and nutrition. Semi-structured interviews were conducted with parents from 16 low-income Early Head Start families. Verbatim interview transcripts, observations, field notes, documentary evidence, and follow-up participant checks were used during grounded theory analysis of the data. Data yielded a potential theoretical model of parental movement toward action involving (a) the culture and context influencing parents, (b) parents' sources of social and cultural messages, (c) parental values and engagement, (d) parental motivation for action, (e) intervening conditions impacting motivation and application, and (f) parent action taken on the individual and social levels. Parent characteristics greatly impacted the ways in which parents understood and applied health and nutrition information. Among other implications, it is recommended that educators and providers focus on a parent's beliefs, values, and cultural preferences regarding food and health behaviors as well as his/her personal/family definition of "health" when framing recommendations and developing interventions.

  16. Precipitation and microphysical processes observed by three polarimetric X-band radars and ground-based instrumentation during HOPE

    Science.gov (United States)

    Xie, Xinxin; Evaristo, Raquel; Simmer, Clemens; Handwerker, Jan; Trömel, Silke

    2016-06-01

    This study presents a first analysis of precipitation and related microphysical processes observed by three polarimetric X-band Doppler radars (BoXPol, JuXPol and KiXPol) in conjunction with a ground-based network of disdrometers, rain gauges and vertically pointing micro rain radars (MRRs) during the High Definition Clouds and Precipitation for advancing Climate Prediction (HD(CP)2) Observational Prototype Experiment (HOPE) during April and May 2013 in Germany. While JuXPol and KiXPol were continuously observing the central HOPE area near Forschungszentrum Jülich at a close distance, BoXPol observed the area from a distance of about 48.5 km. MRRs were deployed in the central HOPE area and one MRR close to BoXPol in Bonn, Germany. Seven disdrometers and three rain gauges providing point precipitation observations were deployed at five locations within a 5 km × 5 km region, while three other disdrometers were collocated with the MRR in Bonn. The daily rainfall accumulation at each rain gauge/disdrometer location estimated from the three X-band polarimetric radar observations showed very good agreement. Accompanying microphysical processes during the evolution of precipitation systems were well captured by the polarimetric X-band radars and corroborated by independent observations from the other ground-based instruments.

  17. Effect of different rates of spent coffee grounds (SCG) on composting process, gaseous emissions and quality of end-product.

    Science.gov (United States)

    Santos, Cátia; Fonseca, João; Aires, Alfredo; Coutinho, João; Trindade, Henrique

    2017-01-01

    The use of spent coffee grounds (SCG) in composting for organic farming is a viable way of valorising these agro-industrial residues. In the present study, four treatments with different amounts of spent coffee grounds (SCG) were established, namely, C0 (Control), C10, C20 and C40, containing 0, 10, 20 and 40% of SCG (DM), respectively; and their effects on the composting process and the end-product quality characteristics were evaluated. The mixtures were completed with Acacia dealbata L. shoots and wheat straw. At different time intervals during composting, carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) emissions were measured and selected physicochemical characteristics of the composts were evaluated. During the composting process, all treatments showed a substantial decrease in total phenolics and total tannins, and an important increase in gallic acid. Emissions of greenhouse gases were very low and no significant difference between the treatments was registered. The results indicated that SCG may be successfully composted in all proportions. However C40, was the treatment which combined better conditions of composting, lower GHG emissions and better quality of end product. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Detectability of underground electrical cables junction with a ground penetrating radar: electromagnetic simulation and experimental measurements

    Science.gov (United States)

    Liu, Xiang; serhir, mohammed; kameni, abelin; lambert, marc; pichon, lionel

    2016-04-01

    For a company like Electricity De France (EDF), being able to detect accurately using non-destructive methods the position of the buried junction between two underground cables is a crucial issue. The junction is the linking part where most maintenance operations are carried out. The challenge of this work is to conduct a feasibility study to confirm or deny the relevance of Ground Penetrating Radar (GPR) to detect these buried junctions in their actual environment against clutter. Indeed, the cables are buried in inhomogeneous medium at around 80cm deep. To do this, the study is conducted in a numerical environment. We use the 3D simulation software CST MWS to model a GPR scenario. In this simulation, we place the already optimized bowtie antennas operating in the frequency band [0.5 GHz - 3 GHz] in front of wet soil (dispersive) and dry soil where the underground cable is placed at 80cm deep. We collect the amplitude and phase of the reflected waves in order to detect the contrast provoked by the geometric dimensions variation of the cable [1] (diameter of the cable is 48mm and the diameter of the junction 74mm). The use of an ultra-wideband antenna is necessary to reconcile resolution and penetration of electromagnetic waves in the medium to be characterized. We focus on the performance of the GPR method according to the characteristics of the surrounding medium in which the electric cables are buried, the polarization of the Tx and Rx antennas. The experimental measurement collected in the EDF site will be presented. The measured data are processed using the clutter reduction method based on digital filtering [2]. We aim at showing that using the developed bowtie antennas that the GPR technique is well adapted for the cable junction localization even in cluttered environment. References [1] D. J. Daniels, "Surface-Penetrating Radar", London, IEE 1996. [2] Potin, D.; Duflos, E.; Vanheeghe, P., "Landmines Ground-Penetrating Radar Signal Enhancement by Digital

  19. The Process of Professional School Counselor Multicultural Competency Development: A Grounded Theory

    Science.gov (United States)

    Berry, Jessica L.

    2013-01-01

    Professional School Counselors who work in schools with a range of student diversity are posed with a unique set of challenges which require them to develop their multicultural competencies. The following qualitative study examined the process of developing multicultural competence for four professional school counselors. The four professional…

  20. Interrelated Processes toward Quality of Life in Survivors of Childhood Cancer: A Grounded Theory

    Science.gov (United States)

    Tsonis, Miranda; McDougall, Janette; Mandich, Angela; Irwin, Jennifer

    2012-01-01

    Past research has not adequately addressed the quality of life (QOL) of survivors of childhood cancer. The purpose of this study was to understand how QOL is experienced for individuals who have survived childhood cancer. Specific research questions included: (a) How do childhood cancer survivors define the concept of QOL and (b) What processes do…

  1. Ground-level ozone in four Chinese cities: precursors, regional transport and heterogeneous processes

    Directory of Open Access Journals (Sweden)

    L. K. Xue

    2014-08-01

    Full Text Available We analyzed measurements of ozone (O3 and its precursors made at rural/suburban sites downwind of four large Chinese cities – Beijing, Shanghai, Guangzhou and Lanzhou, to elucidate their pollution characteristics, regional transport, in situ production, and impacts of heterogeneous processes. The same measurement techniques and observation-based model were used to minimize uncertainties in comparison of the results due to difference in methodologies. All four cities suffered from serious O3 pollution but showed different precursor distributions. The model-calculated in situ O3 production rates were compared with the observed change rates to infer the relative contributions of on-site photochemistry and transport. At the rural site of Beijing, export of the well-processed urban plumes contributed to the extremely high O3 levels (up to an hourly value of 286 ppbv, while the O3 pollution observed at suburban sites of Shanghai, Guangzhou and Lanzhou was dominated by intense in-situ production. The O3 production was in a VOCs-limited regime in both Shanghai and Guangzhou, and a NOx-controlled regime in Lanzhou. The key VOC precursors are aromatics and alkenes in Shanghai, and aromatics in Guangzhou. The potential impacts on O3 production of several heterogeneous processes, namely, hydrolysis of dinitrogen pentoxide (N2O5, uptake of hydro peroxy radical (HO2 on particles and surface reactions of NO2 forming nitrous acid (HONO, were assessed. The analyses indicate the varying and considerable impacts of these processes in different areas of China depending on the atmospheric abundances of aerosol and NOx, and suggest the urgent need to better understand these processes and represent them in photochemical models.

  2. Heritability and Genetic Relationship of Adult Self-Reported Stuttering, Cluttering and Childhood Speech-Language Disorders

    DEFF Research Database (Denmark)

    Fagnani, Corrado; Fibiger, Steen; Skytthe, Axel;

    2011-01-01

    Genetic influence and mutual genetic relationship for adult self-reported childhood speech-language disorders, stuttering, and cluttering were studied. Using nationwide questionnaire answers from 34,944 adult Danish twins, a multivariate biometric analysis based on the liability-threshold model......, 0.78/0.80 for stuttering, and 0.53/0.65 for cluttering. For each trait, the same genes were suggested to affect liability in males and females. Furthermore, high genetic correlations between the traits were obtained; the estimates for childhood speech-language disorders and stuttering were 0.......71/0.79 for males/females, for childhood speech-language disorders and cluttering 0.73/0.56, and for stuttering and cluttering 0.53/0.57. Substantial unique environmental correlations between the traits were also found in both genders. Conclusion: With the limitations related to self-reporting from adult age...

  3. Optimising UAV topographic surveys processed with structure-from-motion: Ground control quality, quantity and bundle adjustment

    Science.gov (United States)

    James, M. R.; Robson, S.; d'Oleire-Oltmanns, S.; Niethammer, U.

    2017-03-01

    Structure-from-motion (SfM) algorithms greatly facilitate the production of detailed topographic models from photographs collected using unmanned aerial vehicles (UAVs). However, the survey quality achieved in published geomorphological studies is highly variable, and sufficient processing details are never provided to understand fully the causes of variability. To address this, we show how survey quality and consistency can be improved through a deeper consideration of the underlying photogrammetric methods. We demonstrate the sensitivity of digital elevation models (DEMs) to processing settings that have not been discussed in the geomorphological literature, yet are a critical part of survey georeferencing, and are responsible for balancing the contributions of tie and control points. We provide a Monte Carlo approach to enable geomorphologists to (1) carefully consider sources of survey error and hence increase the accuracy of SfM-based DEMs and (2) minimise the associated field effort by robust determination of suitable lower-density deployments of ground control. By identifying appropriate processing settings and highlighting photogrammetric issues such as over-parameterisation during camera self-calibration, processing artefacts are reduced and the spatial variability of error minimised. We demonstrate such DEM improvements with a commonly-used SfM-based software (PhotoScan), which we augment with semi-automated and automated identification of ground control points (GCPs) in images, and apply to two contrasting case studies - an erosion gully survey (Taroudant, Morocco) and an active landslide survey (Super-Sauze, France). In the gully survey, refined processing settings eliminated step-like artefacts of up to 50 mm in amplitude, and overall DEM variability with GCP selection improved from 37 to 16 mm. In the much more challenging landslide case study, our processing halved planimetric error to 0.1 m, effectively doubling the frequency at which changes in

  4. Chromium speciation and fractionation in ground and surface waters in the vicinity of chromite ore processing residue disposal sites.

    Science.gov (United States)

    Farmer, John G; Thomas, Rhodri P; Graham, Margaret C; Geelhoed, Jeanine S; Lumsdon, David G; Paterson, Edward

    2002-04-01

    Chromium concentrations of up to 91 mg l(-1) were found by ICP-OES for ground water from nine boreholes at four landfill sites in an area of S.E. Glasgow/S. Lanarkshire where high-lime chromite ore processing residue (COPR) from a local chemical works had been deposited from 1830 to 1968. Surface water concentrations of up to 6.7 mg l(-1) in a local tributary stream fell to 0.11 mg l(-1) in the River Clyde. Two independent techniques of complexation/colorimetry and speciated isotope dilution mass spectrometry (SIDMS) showed that Cr was predominantly (>90%) in hexavalent form (CrVI) as CrO4(2-), as anticipated at the high pH (7.5-12.5) of the sites. Some differences between the implied and directly determined concentrations of dissolved CrIII, however, appeared related to the total organic carbon (TOC) content. This was most significant for the ground water from one borehole that had the highest TOC concentration of 300 mg l(-1) and at which ultrafiltration produced significant decreases in Cr concentration with decreasing size fractions, e.g. complex. This showed for the main Cr-containing fraction, 100 kDa-0.45 microm, that the Cr was associated with a dark brown band characteristic of organic (humic) matter. Comparison of gel electrophoresis and FTIR results for ultrafilter retentates of ground water from this borehole with those for a borehole at another site where CrVI predominated suggested the influence of carboxylate groups, both in reducing CrVI and in forming soluble CrIII-humic complexes. The implications of this for remediation strategies (especially those based on the addition of organic matter) designed to reduce highly mobile and carcinogenic Cr(VI)O4(2-) to the much less harmful CrIII as insoluble Cr(OH)3 are discussed.

  5. Embedded parallel processing based ground control systems for small satellite telemetry

    Science.gov (United States)

    Forman, Michael L.; Hazra, Tushar K.; Troendly, Gregory M.; Nickum, William G.

    1994-01-01

    The use of networked terminals which utilize embedded processing techniques results in totally integrated, flexible, high speed, reliable, and scalable systems suitable for telemetry and data processing applications such as mission operations centers (MOC). Synergies of these terminals, coupled with the capability of terminal to receive incoming data, allow the viewing of any defined display by any terminal from the start of data acquisition. There is no single point of failure (other than with network input) such as exists with configurations where all input data goes through a single front end processor and then to a serial string of workstations. Missions dedicated to NASA's ozone measurements program utilize the methodologies which are discussed, and result in a multimission configuration of low cost, scalable hardware and software which can be run by one flight operations team with low risk.

  6. Modeling and Analysis of Target Echo and Clutter in Range-Dependent Bistatic Environments: FY14 Annual Report for ONR

    Science.gov (United States)

    2014-09-30

    Clutter Model: Range-dependent predictions compared with towed array reverberation and clutter data from the Malta Plateau. In Papadakis and Bjørnø...dependent shallow water area. In John S. Papadakis and Leif Bjørnø, editors, 1st Underwater Acoustic Conference and Exhibition: Proceedings, pages 465–472... Papadakis and Leif Bjørnø, editors, 2nd Underwater Acoustic Conference and Exhibition: Proceedings, pages 715–722, 2014. Conference held at Island of

  7. Modeling and Analysis of Target Echo and Clutter in Range-Dependent Bistatic Environments: FY13 Annual Report for ONR

    Science.gov (United States)

    2013-09-30

    to reverberation ratio for isovelocity waveguides related to Weston Memorial Workshop Scenarios A2.I and A2.IV. In John S. Papadakis and Leif...Ell11] Dale D. Ellis. Solutions to range-dependent reverberation and sonar workshop problems using an adiabatic normal mode model. In Papadakis and...DRDC Clutter Model: Range-dependent predictions compared with towed array reverberation and clutter data from the Malta Plateau. In Papadakis and

  8. Experimental impact cratering provides ground truth data for understanding planetary-scale collision processes

    Science.gov (United States)

    Poelchau, Michael H.; Deutsch, Alex; Kenkmann, Thomas

    2013-04-01

    Impact cratering is generally accepted as one of the primary processes that shape planetary surfaces in the solar system. While post-impact analysis of craters by remote sensing or field work gives many insights into this process, impact cratering experiments have several advantages for impact research: 1) excavation and ejection processes can be directly observed, 2) physical parameters of the experiment are defined and can be varied, and 3) cratered target material can be analyzed post-impact in an unaltered, uneroded state. The main goal of the MEMIN project is to comprehensively quantify impact processes by conducting a stringently controlled experimental impact cratering campaign on the meso-scale with a multidisciplinary analytical approach. As a unique feature we use two-stage light gas guns capable of producing impact craters in the decimeter size-range in solid rocks that, in turn, allow detailed spatial analysis of petrophysical, structural, and geochemical changes in target rocks and ejecta. In total, we have carried out 24 experiments at the facilities of the Fraunhofer EMI, Freiburg - Germany. Steel, aluminum, and iron meteorite projectiles ranging in diameter from 2.5 to 12 mm were accelerated to velocities ranging from 2.5 to 7.8 km/s. Targets were solid rocks, namely sandstone, quartzite and tuff that were either dry or saturated with water. In the experimental setup, high speed framing cameras monitored the impact process, ultrasound sensors were attached to the target to record the passage of the shock wave, and special particle catchers were positioned opposite of the target surface to capture the ejected target and projectile material. In addition to the cratering experiments, planar shock recovery experiments were performed on the target material, and numerical models of the cratering process were developed. The experiments resulted in craters with diameters up to 40 cm, which is unique in laboratory cratering research. Target porosity

  9. Positive Charge Region in Lower Part of Thunderstorm and Preliminary Breakdown Process of Negative Cloud-to-Ground Lightning

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yijun; MENG Qing; LU Weitao; MA Ming; ZHENG Dong; Pau R. Krehbiel

    2009-01-01

    A new lightning locating technology, called Lightning Mapping Array (LMA), has been developed. The system takes advantage of GPS technology to measure the times of arrival (TOA) of lightning impulsive very high frequency (VHF) radiation events at each remote location. The spatiotemporal development processes of lightning are described in three-dimension by measurement of the system with high time resolution (50 ns) and space precision (50-100 m). The charge structures in thunderstorm and their relationship with lightning discharge processes are revealed. The temporal and spatial characteristics of preliminary breakdown process involved in negative cloud-to-ground (CG) lightning discharges are analyzed based on the data of lightning VHF radiation events. The effect of positive charge region in lower part of thunderstorm on the occurrence of negative CG lightning discharge is discussed. The results indicate that the preliminary breakdown process with longer duration in negative CG lightning discharges is an intracloud discharge process. It occurs between negative and positive charge regions located in middle and lower parts of thunderstorm respectively.It initiates from the negative charge region and propagates downward. After propagating into the positive charge region, the lightning channel develops horizontally. The characteristics of the preliminary breakdown process are consistent with that of intracloud lightning discharges. The stepped leaders are initiated by the K type breakdown which occurs in the last stage of the preliminary breakdown process and develops downward through the positive charge region. The existence of positive charge region in lower part of thunderstorm results in the occurrence of preliminary breakdown process with longer duration before the return stroke of negative CG lightning discharges.

  10. Processes and mechanisms of multi-collapse of loess roads in seasonally frozen ground regions:A review

    Institute of Scientific and Technical Information of China (English)

    GuoYu Li; Wei Ma; Fei Wang; YanHu Mu; YunCheng Mao; Xin Hou; Hui Bing

    2015-01-01

    Usually, the collapsible loess widely distributed across the world can serve as a type of foundation soil that meets its strength requirement after dense compaction and elimination of collapsibility. However, many problems such as cracks and differential settlement still occur in loess roads in the seasonally frozen ground regions after several years of op-eration. Many studies have demonstrated that these secondary or multiple collapses primarily result from the repeated freezing-thawing, wetting-drying, and salinization-desalinization cycles. Therefore, we conducted a research program to (1) monitor the in-situ ground temperatures and water content in certain loess roads to understand their changes, (2) study the effects of freezing-thawing, wetting-drying, and salinization-desalinization cycles on geotechnical properties and mi-cro-fabrics of compacted loess in the laboratory, and (3) develop mitigative measures and examine their engineered ef-fectiveness,i.e., their thermal insulating and water-proofing effects in field and laboratory tests. Our results and advances are reviewed and some further research needs are proposed. These findings more clearly explain the processes and mechanisms of secondary and multiple collapse of loess roads. We also offer references for further study of the weakening mechanisms of similar structural soils.

  11. 4D ground penetrating radar measurements as non-invasive means for hydrological process investigation

    Science.gov (United States)

    Jackisch, Conrad; Allroggen, Niklas

    2017-04-01

    The missing vision into the subsurface appears to be a major limiting factor for our hydrological process understanding and theory development. Today, hydrology-related sciences have collected tremendous evidence for soils acting as drainage network and retention stores simultaneously in structured and self-organising domains. However, our present observation technology relies mainly on point-scale sensors, which integrate over a volume of unknown structures and is blind for their distribution. Although heterogeneity is acknowledged at all scales, it is rarely seen as inherent system property. At small scales (soil moisture probe) and at large scales (neutron probe) our measurements leave quite some ambiguity. Consequently, spatially and temporally continuous measurement of soil water states is essential for advancing our understanding and development of subsurface process theories. We present results from several irrigation experiments accompanied by 2D and 3D time-lapse GPR for the development of a novel technique to visualise and quantify water dynamics in the subsurface. Through the comparison of TDR, tracer and gravimetric measurement of soil moisture it becomes apparent that all sensor-based techniques are capable to record temporal dynamics, but are challenged to precisely quantify the measurements and to extrapolate them in space. At the same time excavative methods are very limited in temporal and spatial resolution. The application of non-invasive 4D GPR measurements complements the existing techniques and reveals structural and temporal dynamics simultaneously. By consequently increasing the density of the GPR data recordings in time and space, we find means to process the data also in the time-dimension. This opens ways to quantitatively analyse soil water dynamics in complex settings.

  12. An Improved Sequential Initiation Method for Multitarget Track in Clutter with Large Noise Measurement

    Directory of Open Access Journals (Sweden)

    Daxiong Ji

    2014-01-01

    Full Text Available This paper proposes an improved sequential method for underwater multiple objects tracks initiation in clutter, estimating the initial position for the trajectory. The underwater environment is complex and changeable, and the sonar data are not very ideal. When the detection distance is far, the error of measured data is also great. Besides that, the clutter has a grave effect on the tracks initiation. So it is hard to initialize a track and estimate the initial position. The new tracks initiation is that when at least six of ten points meet the requirements, then we determine that there is a new track and the initial states of the parameters are estimated by the linear least square method. Compared to the conventional tracks initiation methods, our method not only considers the kinematics information of targets, but also regards the error of the sonar sensors as an important element. Computer simulations confirm that the performance of our method is very nice.

  13. Classification of ground moving targets using bicepstrum-based features extracted from Micro-Doppler radar signatures

    Science.gov (United States)

    Molchanov, Pavlo O.; Astola, Jaakko T.; Egiazarian, Karen O.; Totsky, Alexander V.

    2013-12-01

    In this article, a novel bicepstrum-based approach is suggested for ground moving radar target classification. Distinctive classification features were extracted from short-time backscattering bispectrum estimates of the micro-Doppler signature. Real radar data were obtained using surveillance Doppler microwave radar operating at 34 GHz. Classifier performance was studied in detail using the Gaussian Mixture Mode and Maximum Likelihood decision making rule, and the results were verified on a multilayer perceptron and Support Vector Machine. Experimental real radar measurements demonstrated that it is quite feasible to discern three classes of humans (single, two and three persons) walking in a vegetation cluttered environment using proposed bicepstrum-based classification features. Sophisticated bispectrum-based signal processing provides the extraction of new classification features in the form of phase relationships in the radar data. It provides a novel insight into moving radar target classification compared to the commonly used energy-based strategy.

  14. Source Rupture Process and Near-Fault Ground Motions of the 2016 Kumamoto Earthquake Sequence Estimated from Strong Motion Data

    Science.gov (United States)

    Asano, K.; Iwata, T.

    2016-12-01

    The 2016 Kumamoto earthquake sequence started with an MJMA 6.5 foreshock on April 14, 2016 occurring along the northern part of the Hinagu fault, central Kyushu, Japan, and the MJMA 7.3 mainshock occurred just 28 h after the foreshock. Both events brought severe ground motions to the near-source region. We analyzed the kinematic source rupture processes of the foreshock and mainshock by the multiple time window linear waveform inversion using strong motion data (e.g., Hartzell and Heaton, 1983). The foreshock (Mw 6.1) was characterized by right-lateral strike-slip occurring on a nearly vertical fault plane along the northern part of the Hinagu fault, and it had two large-slip areas: one near the hypocenter and another at a shallow depth. These two large-slip areas mainly contribute ground motions in the near-source area. For the analysis of the mainshock, we assumed a fault geometry changing strike and dip angles along the Hinagu and Futagawa faults in accordance with the surface ruptures mapped by emergency field surveys (Kumahara et al., 2016). We assigned point sources densely with an interval of 0.2 km on the assumed fault planes in order to reproduce appropriately near-fault ground motions, and estimated spatiotemporal slip history, which was discretized with an interval of 1.8 km on the fault planes. The estimated source model reveals that the rupture of the mainshock started at a northwest-dipping fault plane along the Hinagu fault, which is close to the vertical fault plane of the foreshock, and almost continuously propagated across the junction of the Hinagu and Futagawa faults. Then the rupture propagated northeastward along the Futagawa fault, and stopped to rupture in the western part of the Aso caldera. The significant slip with 3-5 m were observed on the Futagawa fault, and shallowest part has slip ranging from 1 to 2 m. We also tried to reproduce ground motions observed at some near-fault strong motion stations, which recorded significant coseismic

  15. Adaptive clutter filter in 2-D color flow imaging based on in vivo I/Q signal.

    Science.gov (United States)

    Zhou, Xiaoming; Zhang, Congyao; Liu, Dong C

    2014-01-01

    Color flow imaging has been well applied in clinical diagnosis. For the high quality color flow images, clutter filter is important to separate the Doppler signals from blood and tissue. Traditional clutter filters, such as finite impulse response, infinite impulse response and regression filters, were applied, which are based on the hypothesis that the clutter signal is stationary or tissue moves slowly. However, in realistic clinic color flow imaging, the signals are non-stationary signals because of accelerated moving tissue. For most related papers, simulated RF signals are widely used without in vivo I/Q signal. Hence, in this paper, adaptive polynomial regression filter, which is down mixing with instantaneous clutter frequency, was proposed based on in vivo carotid I/Q signal in realistic color flow imaging. To get the best performance, the optimal polynomial order of polynomial regression filter and the optimal polynomial order for estimation of instantaneous clutter frequency respectively were confirmed. Finally, compared with the mean blood velocity and quality of 2-D color flow image, the experiment results show that adaptive polynomial regression filter, which is down mixing with instantaneous clutter frequency, can significantly enhance the mean blood velocity and get high quality 2-D color flow image.

  16. Real-Time On-Board Processing Validation of MSPI Ground Camera Images

    Science.gov (United States)

    Pingree, Paula J.; Werne, Thomas A.; Bekker, Dmitriy L.

    2010-01-01

    The Earth Sciences Decadal Survey identifies a multiangle, multispectral, high-accuracy polarization imager as one requirement for the Aerosol-Cloud-Ecosystem (ACE) mission. JPL has been developing a Multiangle SpectroPolarimetric Imager (MSPI) as a candidate to fill this need. A key technology development needed for MSPI is on-board signal processing to calculate polarimetry data as imaged by each of the 9 cameras forming the instrument. With funding from NASA's Advanced Information Systems Technology (AIST) Program, JPL is solving the real-time data processing requirements to demonstrate, for the first time, how signal data at 95 Mbytes/sec over 16-channels for each of the 9 multiangle cameras in the spaceborne instrument can be reduced on-board to 0.45 Mbytes/sec. This will produce the intensity and polarization data needed to characterize aerosol and cloud microphysical properties. Using the Xilinx Virtex-5 FPGA including PowerPC440 processors we have implemented a least squares fitting algorithm that extracts intensity and polarimetric parameters in real-time, thereby substantially reducing the image data volume for spacecraft downlink without loss of science information.

  17. Grounding cognitive-level processes in behavior: the view from dynamic systems theory.

    Science.gov (United States)

    Samuelson, Larissa K; Jenkins, Gavin W; Spencer, John P

    2015-04-01

    Marr's seminal work laid out a program of research by specifying key questions for cognitive science at different levels of analysis. Because dynamic systems theory (DST) focuses on time and interdependence of components, DST research programs come to very different conclusions regarding the nature of cognitive change. We review a specific DST approach to cognitive-level processes: dynamic field theory (DFT). We review research applying DFT to several cognitive-level processes: object permanence, naming hierarchical categories, and inferring intent, that demonstrate the difference in understanding of behavior and cognition that results from a DST perspective. These point to a central challenge for cognitive science research as defined by Marr-emergence. We argue that appreciating emergence raises questions about the utility of computational-level analyses and opens the door to insights concerning the origin of novel forms of behavior and thought (e.g., a new chess strategy). We contend this is one of the most fundamental questions about cognition and behavior. Copyright © 2015 Cognitive Science Society, Inc.

  18. Cognitive software defined radar: waveform design for clutter and interference suppression

    Science.gov (United States)

    Kirk, Benjamin H.; Owen, Jonathan W.; Narayanan, Ram M.; Blunt, Shannon D.; Martone, Anthony F.; Sherbondy, Kelly D.

    2017-05-01

    Clutter and radio frequency interference (RFI) are prevalent issues in the field of radar and are specifically of interest to of cognitive radar. Here, methods for applying and testing the utility of cognitive radar for clutter and RFI mitigation are explored. Using the adaptable transmit capability, environmental database, and general "awareness" of a cognitive radar system (i.e. spectrum sensing, geographical location, etc.), a matched waveform is synthesized that improves the signal-to-clutter ratio (SCR), assuming at least an estimate of the target response and the environmental clutter response are known a prior i. RFI may also be mitigated by sensing the RF spectrum and adapting the transmit center frequency and bandwidth using methods that optimize bandwidth and signal-to-interference plus noise ratio (SINR) (i.e. the spectrum sensing, multi-objective (SS-MO) algorithm). The improvement is shown by a decrease in the noise floor. The above methods' effectiveness are examined via a test-bed developed around a software defined radio (SDR). Testing and the general use of commercial off the shelf (COTS) devices are desirable for their cost effectiveness, general ease of use, as well as technical and community support, but these devices provide design challenges in order to be effective. The universal software radio peripheral (USRP) X310 SDR is a relatively cheap and portable device that has all the system components of a basic cognitive radar. Design challenges of the SDR include phase coherency between channels, bandwidth limitations, dynamic range, and speed of computation and data communication / recording.

  19. Calculation of Radar Probability of Detection in K-Distributed Sea Clutter and Noise

    Science.gov (United States)

    2011-04-01

    Expanded Swerling Target Models, IEEE Trans. AES 39 (2003) 1059-1069. 18. G. Arfken , Mathematical Methods for Physicists, Second Edition, Academic...form solution for the probability of detection in K-distributed clutter, so numerical methods are required. The K distribution is a compound model...the integration, with the nodes and weights calculated using matrix methods , so that a general purpose numerical integration routine is not required

  20. Measurements and Analysis of Reverberation, Target Echo, and Clutter: FY10 Annual Report for ONR

    Science.gov (United States)

    2010-09-30

    NATO Undersea Research Centre ( NURC ). The primary effort is analysis and interpretation of data, together with development and validation of improved...Research Projects (JRPs) between NURC , Canada, and several US research laboratories (ARL in particular). The present JRP “Characterizing and Reducing...Canada/ NURC Joint Research Project “Characterizing and Reducing Clutter in Broadband Active Sonar” which received substantial funding from ONR. A

  1. Quasi-Analytic Model of OTHR Clutter from Equatorial Bubbles in the Ionosphere

    Science.gov (United States)

    2006-02-27

    raytrace code developed to study OTH radar clutter is based on the theory provided by Hazelgrove [1954], Yeh and Liu [1972], Jones and Stephenson [1975... radar (OTHR) sky wave becomes Doppler shifted because the ionosphere through which the radio rays are propagating changes. One source of these changes...trace computations to yield predictions for Doppler shifts in the unstable ionosphere. 15. SUBJECT TERMS Over-the-horizon radar Computer model of the

  2. Biogeochemical Processes Responsible for the Enhanced Transport of Plutonium Under transient Unsaturated Ground Water Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Fred J. Molz, III

    2010-05-28

    to Pu uptake by corn roots and xylem transport. Plants were started in wet paper wrapped around each corn seed. When the tap roots were sufficiently long, the seedlings were transplanted to a soil container with the tap root extending out the container bottom. The soil container was then placed over a nutrient solution container, and the solution served as an additional medium for root growth. To conduct an uptake study, a radioactive substance, such as Pu complexed with the bacterial siderophore DFOB, was added to the nutrient solution. After a suitable elapsed time, the corn plant was sacrificed, cut into 10 cm lengths, and the activity distribution measured. Experimental results clarified the basic nature of Pu uptake and transport in corn plants, and resulting simulations suggested that each growing season Pu in the SRS lysimeters would move into the plant shoots and be deposited on the soil surface during the Fall dieback. Subsequent isotope ratio analyses showed that this did happen. OVERALL RESULTS AND CONCLUSIONS - (1) Pu transport downward from the source is controlled by advection, dispersion and adsorption, along with surface-mediated REDOX reactions. (2) Hysteresis, extreme root distribution functions, air-content dependent oxidation rate constants, and large evaporation rates from the soil surface were not able to explain the observed upward migration of Pu. (3) Small amounts of Pu uptake by plant roots and translocation in the transpiration stream creates a realistic mechanism for upward Pu migration (4) Realistic xylem cross-sectional areas imply high flow velocities under hot, wet conditions. Such flow velocities produce the correct shape for the observed activity distributions in the top 20 cm of the lysimeter soil. (5) Simulations imply that Pu should have moved into the above-ground grass tissue each year during the duration of the experiments, resulting in an activity residual accumulating on the soil surface. An isotope ratio analysis showed that

  3. Standards and Specifications for Ground Processing of Space Vehicles: From an Aviation-Based Shuttle Project to Global Application

    Science.gov (United States)

    Ingalls, John; Cipolletti, John

    2011-01-01

    Proprietary or unique designs and operations are expected early in any industry's development, and often provide a competitive early market advantage. However, there comes a time when a product or industry requires standardization for the whole industry to advance...or survive. For the space industry, that time has come. Here, we will focus on standardization of ground processing for space vehicles and their ground systems. With the retirement of the Space Shuttle, and emergence of a new global space race, affordability and sustainability are more important now than ever. The growing commercialization of the space industry and current global economic environment are driving greater need for efficiencies to save time and money. More RLV's (Reusable Launch Vehicles) are being developed for the gains of reusability not achievable with traditional ELV's (Expendable Launch Vehicles). More crew/passenger vehicles are also being developed. All of this calls for more attention needed for ground processing-repeatedly before launch and after landing/recovery. RLV's should provide more efficiencies than ELV's, as long as MRO (Maintenance, Repair, and Overhaul) is well-planned-even for the unplanned problems. NASA's Space Shuttle is a primary example of an RLV which was supposed to thrive on reusability savings with efficient ground operations, but lessons learned show that costs were (and still are) much greater than expected. International standards and specifications can provide the commonality needed to simplify design and manufacturing as well as to improve safety, quality, maintenance, and operability. There are standards organizations engaged in the space industry, but ground processing is one of the areas least addressed. Challenges are encountered due to various factors often not considered during development. Multiple vehicle elements, sites, customers, and contractors pose various functional and integration difficulties. Resulting technical publication structures

  4. COST Action TU1208 - Working Group 3 - Electromagnetic modelling, inversion, imaging and data-processing techniques for Ground Penetrating Radar

    Science.gov (United States)

    Pajewski, Lara; Giannopoulos, Antonios; Sesnic, Silvestar; Randazzo, Andrea; Lambot, Sébastien; Benedetto, Francesco; Economou, Nikos

    2017-04-01

    This work aims at presenting the main results achieved by Working Group (WG) 3 "Electromagnetic methods for near-field scattering problems by buried structures; data processing techniques" of the COST (European COoperation in Science and Technology) Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" (www.GPRadar.eu, www.cost.eu). The main objective of the Action, started in April 2013 and ending in October 2017, is to exchange and increase scientific-technical knowledge and experience of Ground Penetrating Radar (GPR) techniques in civil engineering, whilst promoting in Europe the effective use of this safe non-destructive technique. The Action involves more than 150 Institutions from 28 COST Countries, a Cooperating State, 6 Near Neighbour Countries and 6 International Partner Countries. Among the most interesting achievements of WG3, we wish to mention the following ones: (i) A new open-source version of the finite-difference time-domain simulator gprMax was developed and released. The new gprMax is written in Python and includes many advanced features such as anisotropic and dispersive-material modelling, building of realistic heterogeneous objects with rough surfaces, built-in libraries of antenna models, optimisation of parameters based on Taguchi's method - and more. (ii) A new freeware CAD was developed and released, for the construction of two-dimensional gprMax models. This tool also includes scripts easing the execution of gprMax on multi-core machines or network of computers and scripts for a basic plotting of gprMax results. (iii) A series of interesting freeware codes were developed will be released by the end of the Action, implementing differential and integral forward-scattering methods, for the solution of simple electromagnetic problems by buried objects. (iv) An open database of synthetic and experimental GPR radargrams was created, in cooperation with WG2. The idea behind this initiative is to give researchers the

  5. Duct heights inferred from radar sea clutter using proper orthogonal bases

    Science.gov (United States)

    Fountoulakis, Vasileios; Earls, Christopher

    2016-10-01

    Maritime electromagnetic (EM)-based communication and detection systems are strongly influenced by meteorological conditions, as they can cause anomalous electromagnetic propagation within the surface layer. To predict the performance of such systems, detailed knowledge of the refractivity profile is required. In recent years, refractivity from clutter (RFC) methods has been developed to estimate this refractivity profile by measuring radar clutter return from the rough ocean surface. The current work proposes an RFC framework that utilizes a novel surrogate model for EM propagation. The surrogate model is based on an offline created library of sparsely sampled field data of clutter returns, compressed into proper orthogonal bases, and indexed on specific surface layer refractive parameters. By exploiting the Riemannian manifold structure of the space that proper orthogonal bases occur in, we are able to interpolate among them. This, then, enables us to use the surrogate model in an inverse problem setting, whose goal is to uncover in situ maritime EM propagation conditions efficiently. We demonstrate the feasibility of our proposed surrogate model-based RFC approach for evaporation duct by testing it with field data obtained from an experimental campaign.

  6. Age differences in search of web pages: the effects of link size, link number, and clutter.

    Science.gov (United States)

    Grahame, Michael; Laberge, Jason; Scialfa, Charles T

    2004-01-01

    Reaction time, eye movements, and errors were measured during visual search of Web pages to determine age-related differences in performance as a function of link size, link number, link location, and clutter. Participants (15 young adults, M = 23 years; 14 older adults, M = 57 years) searched Web pages for target links that varied from trial to trial. During one half of the trials, links were enlarged from 10-point to 12-point font. Target location was distributed among the left, center, and bottom portions of the screen. Clutter was manipulated according to the percentage of used space, including graphics and text, and the number of potentially distracting nontarget links was varied. Increased link size improved performance, whereas increased clutter and links hampered search, especially for older adults. Results also showed that links located in the left region of the page were found most easily. Actual or potential applications of this research include Web site design to increase usability, particularly for older adults.

  7. Curl-meter of Electrical Fields In The Ground.

    Science.gov (United States)

    Krylov, S. M.; Maibuk, Z.-Ju. Ja.; Nikiforova, N. N.

    A special instrument U curl-meter was designed and manufactured in the Institute of Physics of the Earth of RAS for measuring of variable electric fields during alternation of stressedly-deformed state in rock mass. The instrument consist the four-electrode unit and a circuit of analogue signal processing for separation of E U circulations or according to the StokesSs theorem, Curl E in absence of indirect sources. Four electrodes are laied out in rocks on angles of square and they are affixed by ring-type circuit to uninverting inputs of precision operational amplifiers. First input is connected to electrode N1, the second one is connected to N2 and so on. The independent inputs are grounded to a arbitrary point (the fifth electrode is SzeroT). The transmission factors of the circuit are set by resistors accurate to within 0.25 %. First and third, and also second and fourth outputs of the amplifiers are connected to the grad EX and grad EY calculation circuit (deduction circuits). So, if the vector components have different signs of both two EX values and two values EY, the gradient calculation circuit generates signal extremums. If in this case the signs inside pairs are identical , that means that the signal not- ring-type and it is absent on output (difference of the equal values with equal signs). The signals from outputs of the gradient calculations act into adding device for calculation of Curl E (circulation). Curl-meter differs by high security from clutters and from cues on any of inputs rather of "zero point" (ground) reacting only on a ring-type current, thus it is essential (on the order) the noise level and drift of operational amplifiers is moderated. Curl-meter works in a complex of measuring devices on Obninsk seismological polygon for study of behavior of superlow frequency of tectonic genesis electromagnetic emission. Through four inputs (electrode spacing 7x7 2, resistance between welding rods 0.8 - 1.1 kOm), manufactured from fine- dyspersated

  8. The Process of Parents' Decision-Making to Discharge Their Child against Medical Advice (DAMA: A grounded theory study

    Directory of Open Access Journals (Sweden)

    Nikbakht Nasrabadi Alireza

    2016-05-01

    Full Text Available Discharge against medical advice (DAMA refers to the phenomenon that patient or the patient’s surrogate decides to leave the hospital before the attending physician confirms the patient is discharged. Children are much more vulnerable to such discharges. This process occurs with different mechanisms that identifying them can be helpful in reducing this phenomenon. We aimed to explore the process of parents' decision-making to discharge their child against medical advice. In-depth, semi-structured interviews were conducted with 10 fathers, 10 mothers, 6 nurses and 3 physician assistants and the data were collected to the point of saturation. Grounded theory methodology was adopted for data collection and analysis. The results of qualitative analysis in the field of the parents' decisionmaking on the DAMA revealed 4 main themes: "lack of family-centered care", "disruption of the parenting process", "distrust to the medical team and center" and "psychological strategy of shirk responsibility for child care and treatment ". By providing family-centered care, adopting measures to empowering the families, developing the trust of parents to the health care team and developing a discharge plan from the beginning of children hospitalization with the cooperation of health care team and parents and considering all factors such as child's special health condition and parent's health related perceptions and beliefs, children will not be discharged against medical advice and will experience better outcomes.

  9. The evolution of discharge current and channel radius in cloud-to-ground lightning return stroke process

    Science.gov (United States)

    Fan, Tingting; Yuan, Ping; Wang, Xuejuan; Cen, Jianyong; Chang, Xuan; Zhao, Yanyan

    2017-09-01

    The spectra of two negative cloud-to-ground lightning discharge processes with multi-return strokes are obtained by a slit-less high-speed spectrograph, which the temporal resolution is 110 μs. Combined with the synchronous electrical observation data and theoretical calculation, the physical characteristics during return strokes process are analysed. A positive correlation between discharge current and intensity of ionic lines in the spectra is verified, and based on this feature, the current evolution characteristics during four return strokes are investigated. The results show that the time from peak current to the half-peak value estimated by multi point-fitting is about 101 μs-139 μs. The Joule heat in per unit length of four return strokes channel is in the order of 105J/m-106 J/m. The radius of arc discharge channel is positively related to the discharge current, and the more intense the current is, the greater the radius of channel is. Furthermore, the evolution for radius of arc core channel in the process of return stroke is consistent with the change trend of discharge current after the peak value. Compared with the decay of the current, the temperature decreases more slowly.

  10. Coordinated polar spacecraft, geosynchronous spacecraft, and ground-based observations of magnetopause processes and their coupling to the ionosphere

    Directory of Open Access Journals (Sweden)

    G. Le

    2004-12-01

    Full Text Available In this paper, we present in-situ observations of processes occurring at the magnetopause and vicinity, including surface waves, oscillatory magnetospheric field lines, and flux transfer events, and coordinated observations at geosynchronous orbit by the GOES spacecraft, and on the ground by CANOPUS and 210° Magnetic Meridian (210MM magnetometer arrays. On 7 February 2002, during a high-speed solar wind stream, the Polar spacecraft was skimming the magnetopause in a post-noon meridian plane for ~3h. During this interval, it made two short excursions and a few partial crossings into the magnetosheath and observed quasi-periodic cold ion bursts in the region adjacent to the magnetopause current layer. The multiple magnetopause crossings, as well as the velocity of the cold ion bursts, indicate that the magnetopause was oscillating with an ~6-min period. Simultaneous observations of Pc5 waves at geosynchronous orbit by the GOES spacecraft and on the ground by the CANOPUS magnetometer array reveal that these magnetospheric pulsations were forced oscillations of magnetic field lines directly driven by the magnetopause oscillations. The magnetospheric pulsations occurred only in a limited longitudinal region in the post-noon dayside sector, and were not a global phenomenon, as one would expect for global field line resonance. Thus, the magnetopause oscillations at the source were also limited to a localized region spanning ~4h in local time. These observations suggest that it is unlikely that the Kelvin-Helmholz instability and/or fluctuations in the solar wind dynamic pressure were the direct driving mechanisms for the observed boundary oscillations. Instead, the likely mechanism for the localized boundary oscillations was pulsed reconnection at the magnetopause occurring along the X-line extending over the same 4-h region. The Pc5 band pressure fluctuations commonly seen in high-speed solar wind streams may modulate the reconnection rate as

  11. 基于星载双天线的月球表面杂波抑制方法研究%Research on Lunar Surface Clutter Cancellation Method Based on Spaceborne Dual- antenna

    Institute of Scientific and Technical Information of China (English)

    王莹瑛; 方广有

    2011-01-01

    Spaceborne Radio Echo Sounder (RES) is a promising opportunity to investigate planets subsurface. Geological feature of subsurface layers was essential to understand the origin and evolution process of planets. For spacebome RES, the return signal was the sum of the surface clutter and subsurface reflected signal. How to reduce the surface clutter was a hot issue in RES technology field. The ESA's Mars Expess Mission carried a spaceborne radar sounder called MARSIS and applied the dual - antenna method. This paper deduced the mathematical formulation of dual-antenna clutter cancellation. Numerical simulation results show that the signal to clutter ratio is effectively improved and this method can be used in Moon exploration.%研究星载双天线优化问题,针对更好地提取地下分层结构的回波,星载射频回波探测仪RES(Radio Echo Sounder)在行星内部结构探测.为了对表面杂波进行抑制,利用双天线抑制月球表面杂波的数学模型.对于星载RES系统,接收信号包括表面杂波和地下分层结构产生的回波.对杂波要进行有效地抑制.根据ESA火星快车MARSIS高频雷达系统中使用的双天线技术进行仿真.数值计算表明采用双天线杂波抑制法可以显著提高回波的信杂比,可以应用到月球探测中.

  12. Robust frequency diversity based algorithm for clutter noise reduction of ultrasonic signals using multiple sub-spectrum phase coherence

    Energy Technology Data Exchange (ETDEWEB)

    Gongzhang, R.; Xiao, B.; Lardner, T.; Gachagan, A. [Centre for Ultrasonic Engineering, University of Strathclyde, Glasgow, G1 1XW (United Kingdom); Li, M. [School of Engineering, University of Glasgow, Glasgow, G12 8QQ (United Kingdom)

    2014-02-18

    This paper presents a robust frequency diversity based algorithm for clutter reduction in ultrasonic A-scan waveforms. The performance of conventional spectral-temporal techniques like Split Spectrum Processing (SSP) is highly dependent on the parameter selection, especially when the signal to noise ratio (SNR) is low. Although spatial beamforming offers noise reduction with less sensitivity to parameter variation, phased array techniques are not always available. The proposed algorithm first selects an ascending series of frequency bands. A signal is reconstructed for each selected band in which a defect is present when all frequency components are in uniform sign. Combining all reconstructed signals through averaging gives a probability profile of potential defect position. To facilitate data collection and validate the proposed algorithm, Full Matrix Capture is applied on the austenitic steel and high nickel alloy (HNA) samples with 5MHz transducer arrays. When processing A-scan signals with unrefined parameters, the proposed algorithm enhances SNR by 20dB for both samples and consequently, defects are more visible in B-scan images created from the large amount of A-scan traces. Importantly, the proposed algorithm is considered robust, while SSP is shown to fail on the austenitic steel data and achieves less SNR enhancement on the HNA data.

  13. New adaptive clutter rejection based on spectral analysis for ultrasound color Doppler imaging: phantom and in vivo abdominal study.

    Science.gov (United States)

    Geunyong Park; Sunmi Yeo; Jae Jin Lee; Changhan Yoon; Hyun-Woo Koh; Hyungjoon Lim; Youngtae Kim; Hwan Shim; Yangmo Yoo

    2014-01-01

    Effective rejection of time-varying clutter originating from slowly moving vessels and surrounding tissues is important for depicting hemodynamics in ultrasound color Doppler imaging (CDI). In this paper, a new adaptive clutter rejection method based on spectral analysis (ACR-SA) is presented for suppressing nonstationary clutter. In ACR-SA, tissue and flow characteristics are analyzed by singular value decomposition and tissue acceleration of backscattered Doppler signals to determine an appropriate clutter filter from a set of clutter filters. To evaluate the ACR-SA method, 20 frames of complex baseband data were acquired by a commercial ultrasound system equipped with a research package (Accuvix V10, Samsung Medison, Seoul, Korea) using a 3.5-MHz convex array probe by introducing tissue movements to the flow phantom (Gammex 1425 A LE, Gammex, Middleton, WI, USA). In addition, 20 frames of in vivo abdominal data from five volunteers were captured. From the phantom experiment, the ACR-SA method provided 2.43 dB (p SCR) compared to static (STA) and down-mixing (ACR-DM) methods. Similarly, it showed smaller values in fractional residual clutter area (FRCA) compared to the STA and ACR-DM methods (i.e., 2.3% versus 5.4% and 3.7%, respectively, ). The consistent improvements in SCR from the proposed ACR-SA method were obtained with the in vivo abdominal data (i.e., 4.97 dB and 3.39 dB over STA and ACR-DM, respectively). The ACR-SA method showed less than 1% FRCA values for all in vivo abdominal data. These results indicate that the proposed ACR-SA method can improve image quality in CDI by providing enhanced rejection of nonstationary clutter.

  14. Observation and study on the whole process of cloud-to-ground lightning using narrowband radio interferometer

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A narrowband radio interferometer has been developed and used to locate the entire sources of VHF radiations from a negative cloud-to-ground (CG) lightning discharge which contains 19 strokes. This system uses five antennas to form an array consisting of short- and long-baselines along two or- thogonal directions. The system error which comes from frequency conversion is reduced by phase detection through direct high frequency amplifying. An interactive graphic analysis procedure is used to remove the fringe ambiguities which exist inherently in interferometry and to determine the direction of lightning radiation sources in two dimensions (azimuth and elevation) as a function of time at a time resolution of microsecond orders. With the developed system, the whole progression process in time and space of a lightning flash can be reconstructed. In this paper, combining the synchronous data of electric filed change and VHF radiation, the whole processes of an example negative CG flash have been studied in detail. It is found that the preliminary breakdown event of the CG flash started from negative charge region and exhibited firstly a downward pregression and then an upward propagation. There were very intense and continuous radiations during stepped leaders which became much stronger when the first return stroke began. In contrast, there were less and only discrete radiations during dart leaders. Stepped leader and dart leader may transform to each other depending on the state of the ionization of the path. The progression speed of initial stepped leaders was about 105 ms?1, while that was about 4.1×106 and 6.0×106 ms?1 for dart leaders and dart-stepped leaders, respectively. M events produced hook-shaped field changes accompanied by active burst of radiations at their begin- nings. Followed these active radiation processes, M events appeared to contact finally into conducting main discharge channels. The mean progression speed of M events was about 7×107 ms?1

  15. Observation and study on the whole process of cloud-to-ground lightning using narrowband radio interferometer

    Institute of Scientific and Technical Information of China (English)

    ZHANG GuangShu; ZHAO YuXiang; QIE XiuShu; ZHANG Tong; WANG YanHui; CHEN ChengPin

    2008-01-01

    A narrowband radio interferometer has been developed and used to locate the entire sources of VHF radiations from a negative cloud-to-ground (CG) lightning ischarge which contains 19 strokes. This system uses five antennas to form an array consisting of short- and long-baselines along two or-thogonal directions. The system error which comes from frequency conversion is reduced by phase detection through direct high frequency amplifying. An interactive graphic analysis procedure is used to remove the fringe ambiguities which exist inherently in interferometry and to determine the direction of lightning radiation sources in two dimensions (azimuth and elevation) as a function of time at a time resolution of microsecond orders. With the developed system, the whole progression process in time and space of a lightning flash can be reconstructed, in this paper, combining the synchronous data of electric filed change and VHF radiation, the whole processes of an example negative CG flash have been studied in detail. It is found that the preliminary breakdown event of the CG flash started from negative charge region and exhibited firstly a downward pregression and then an upward propagation. There were very intense and continuous radiations during stepped leaders which became much stronger when the first return stroke began. In contrast, there were less and only discrete radiations during dart leaders. Stepped leader and dart leader may transform to each other depending on the state of the ionization of the path. The progression speed of initial stepped leaders was about 105 ms-1, while that was about 4.1×106 and 6.0×106 ms-1 for dart leaders and dart-stepped leaders, respectively. M events produced hook-shaped field changes accompanied by active burst of radiations at their begin-nings. Followed these active radiation processes, M events appeared to contact finally into conducting main discharge channels. The mean progression speed of M events was about 7×107 ms-1

  16. Reclaiming life on one's own terms: a grounded theory study of the process of breast cancer survivorship.

    Science.gov (United States)

    Sherman, Deborah Witt; Rosedale, Mary; Haber, Judith

    2012-05-01

    To develop a substantive theory of the process of breast cancer survivorship. Grounded theory. A LISTSERV announcement posted on the SHARE Web site and purposeful recruitment of women known to be diagnosed and treated for breast cancer. 15 women diagnosed with early-stage breast cancer. Constant comparative analysis. Breast cancer survivorship. The core variable identified was Reclaiming Life on One's Own Terms. The perceptions and experiences of the participants revealed overall that the diagnosis of breast cancer was a turning point in life and the stimulus for change. That was followed by the recognition of breast cancer as now being a part of life, leading to the necessity of learning to live with breast cancer, and finally, creating a new life after breast cancer. Participants revealed that breast cancer survivorship is a process marked and shaped by time, the perception of support, and coming to terms with the trauma of a cancer diagnosis and the aftermath of treatment. The process of survivorship continues by assuming an active role in self-healing, gaining a new perspective and reconciling paradoxes, creating a new mindset and moving to a new normal, developing a new way of being in the world on one's own terms, and experiencing growth through adversity beyond survivorship. The process of survivorship for women with breast cancer is an evolutionary journey with short- and long-term challenges. This study shows the development of an empirically testable theory of survivorship that describes and predicts women's experiences following breast cancer treatment from the initial phase of recovery and beyond. The theory also informs interventions that not only reduce negative outcomes, but promote ongoing healing, adjustment, and resilience over time.

  17. Modeling ground vehicle acoustic signatures for analysis and synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Haschke, G. [Sandia National Labs., Albuquerque, NM (United States); Stanfield, R. [US Army CECOM, Night Vision and Electronic Sensors Directorate, Fort Belvoir, VA (United States)

    1995-07-01

    Security and weapon systems use acoustic sensor signals to classify and identify moving ground vehicles. Developing robust signal processing algorithms for this is expensive, particularly in presence of acoustic clutter or countermeasures. This paper proposes a parametric ground vehicle acoustic signature model to aid the system designer in understanding which signature features are important, developing corresponding feature extraction algorithms and generating low-cost, high-fidelity synthetic signatures for testing. The authors have proposed computer-generated acoustic signatures of armored, tracked ground vehicles to deceive acoustic-sensored smart munitions. They have developed quantitative measures of how accurately a synthetic acoustic signature matches those produced by actual vehicles. This paper describes parameters of the model used to generate these synthetic signatures and suggests methods for extracting these parameters from signatures of valid vehicle encounters. The model incorporates wide-bandwidth and narrow- bandwidth components that are modulated in a pseudo-random fashion to mimic the time dynamics of valid vehicle signatures. Narrow- bandwidth feature extraction techniques estimate frequency, amplitude and phase information contained in a single set of narrow frequency- band harmonics. Wide-bandwidth feature extraction techniques estimate parameters of a correlated-noise-floor model. Finally, the authors propose a method of modeling the time dynamics of the harmonic amplitudes as a means adding necessary time-varying features to the narrow-bandwidth signal components. The authors present results of applying this modeling technique to acoustic signatures recorded during encounters with one armored, tracked vehicle. Similar modeling techniques can be applied to security systems.

  18. Ground-penetrating radar study of beach-ridge deposits in Huangqihai Lake, North China: the imprint of washover processes

    Institute of Scientific and Technical Information of China (English)

    Xin SHAN; Xinghe YU; Peter D.CLIFT; Chengpeng TAN; Shunli LI; Zhixing WANG; Dongxu SU

    2016-01-01

    Determining the origin of beach ridges in lacustrine basins can often be problematic.The sedimentary processes responsible for formation of beach ridges on the north shore of Huangqihai Lake were investigated by using ground penetrating radar (GPR).A 400 MHz GPR antenna was used to achieve a high vertical resolution of 0.04-0.08 m.The radar stratigraphy was then determined using principles of seismic stratigraphy.The radar facies (RF) were determined by analyzing internal configuration and continuity of reflections,as well as reflection termination patterns.The identified RF fall into three groups (inclined,horizontal and irregular).The inclined group consists of RF that display inclined reflections.The horizontal group consists of RF that exhibit predominantly horizontal reflections.In the irregular group,the reflections are typically weak.RF with reflections with gently landward dips in the shore-normal profile are interpreted as washover sheet deposits.RF with steeply landward-dipping and imbricated reflections are interpreted as washover lobes.Washover sheets develop when overwash fails to enter a significant body of water and sedimentation takes place entirely on the relatively flattened topography.Washover lobe development occurs when overwash enters a region in which topography dips steeply landward,and sedimentation takes place on the surface of washover sheets or previous washover lobes.The beach-ridge deposits are interpreted as being formed entirely from vertically and laterally stacked washover sheets and washover lobes.They were formed by wave-dominated processes and secondary overwash processes supplemented by longshore currents.

  19. Logarithmic r-θ mapping for hybrid optical neural network filter for multiple objects recognition within cluttered scenes

    Science.gov (United States)

    Kypraios, Ioannis; Young, Rupert C. D.; Chatwin, Chris R.; Birch, Phil M.

    2009-04-01

    θThe window unit in the design of the complex logarithmic r-θ mapping for hybrid optical neural network filter can allow multiple objects of the same class to be detected within the input image. Additionally, the architecture of the neural network unit of the complex logarithmic r-θ mapping for hybrid optical neural network filter becomes attractive for accommodating the recognition of multiple objects of different classes within the input image by modifying the output layer of the unit. We test the overall filter for multiple objects of the same and of different classes' recognition within cluttered input images and video sequences of cluttered scenes. Logarithmic r-θ mapping for hybrid optical neural network filter is shown to exhibit with a single pass over the input data simultaneously in-plane rotation, out-of-plane rotation, scale, log r-θ map translation and shift invariance, and good clutter tolerance by recognizing correctly the different objects within the cluttered scenes. We record in our results additional extracted information from the cluttered scenes about the objects' relative position, scale and in-plane rotation.

  20. Generation of Clutter within a Structured Target Synthesizer

    Science.gov (United States)

    2012-09-01

    microprocessor. Along with the phase and gain coefficients, every ( , )m n is processed through a phase adder , a look-up table (LUT), a gain block...and a summation adder within each range bin modulator. From Figure 5, the DRFM sampled phase is first added to the phase coefficient ( , )inc r n...through the phase adder and the resultant output is given as ˆ( , , ) ( , ) ( , )incr m n m n r n    (3.14) which implies the phase of the

  1. Joint statistical correction of clutters, spokes and beam height for a radar climatology in Southern Germany

    Directory of Open Access Journals (Sweden)

    A. Wagner

    2012-04-01

    Full Text Available Extensive corrections of radar data are a crucial prerequisite for radar derived climatology. This kind of climatology demands a high level of data quality. Little deviations or minor systematic underestimations or overestimations in single radar images become a major cause of error in statistical analysis. First results of radar derived climatology have emerged over the last years, as data sets of appropriate extent are becoming available. Usually, these statistics are based on time series lasting up to ten years as storage of radar data was not achieved before.

    We present a new statistical post-correction scheme, which is based on seven years of radar data of the Munich weather radar (2000–2006 that is operated by DWD (German Weather Service. The typical correction algorithms for single radar images, such as clutter corrections, are used. Then an additional statistical post-correction based on the results of a climatological analysis from radar images follows. The aim of this statistical correction is to correct systematic errors caused by clutter effects or measuring effects but to conserve small-scale natural variations in space.

    The statistical correction is based on a thorough analysis of the different causes of possible errors for the Munich weather radar. This robust analysis revealed the following basic effects: the decrease of rain rate in relation to height and distance from the radar, clutter effects such as remaining clutter, eliminated clutter or shading effects from obstacles near the radar, visible as spokes, as well as the influence of the Bright Band. The correction algorithm is correspondingly based on these results. It consists of three modules. The first one is an altitude correction, which minimizes measuring effects. The second module corrects clutter effects and the third one realizes a mean adjustment to selected rain gauges. Two different radar products are used. The statistical analysis as well as

  2. Adolescent girls' experiences of underlying social processes triggering stress in their everyday life: a grounded theory study.

    Science.gov (United States)

    Haraldsson, Katarina; Lindgren, Eva-Carin; Mattsson, Bengt; Fridlund, Bengt; Marklund, Bertil

    2011-04-01

    The aim of this study was to generate a theoretical model of underlying social processes that trigger stress in adolescent girls' everyday life. In-depth interviews regarding the experiences of stress at home, school and during leisure time were conducted with 14 17-year-old schoolgirls. Data were analysed by means of the grounded theory method. Stress was triggered in the interaction between responsibility and the way in which the girls were encountered. Triggered emotional reactions took the form of four dimensions of stress included ambivalence, frustration, despair and downheartedness. These reactions were dependent on whether the girls voluntary assumed responsibility for various situations or whether they were forced, or felt they were being forced, to assume responsibility in interaction with an encounter characterized by closeness or distance. These forms of stress reactions could appear in one dimension and subsequently shift to another. From the public health perspective, the generated stress model can be used in the planning and implementation of future actions to prevent stress and promote well-being related to stress in adolescent girls.

  3. Nursing care process for releasing psychiatric inpatients from long-term seclusion in Japan: modified grounded theory approach.

    Science.gov (United States)

    Nagayama, Yutaka; Hasegawa, Masami

    2014-09-01

    Based on a modified grounded theory approach, in this study, we sought to elucidate the nursing care process used to guide psychiatric inpatients in long-term seclusion towards release from seclusion. Participant observations and interviews were conducted with a total of 18 nurses from three long-term psychiatric wards at two institutions from September 2011 to November 2012, to collect data on the nursing care they provided for psychiatric patients in long-term seclusion. Consequently, four categories and 15 concepts were extracted. The nurses viewed "a mature therapeutic environment that utilizes flexible apportionment of care" as the foundation (i.e. the core category) in guiding psychiatric inpatients towards release from long-term seclusion. The results revealed a care structure in which nurses in such a treatment environment provided care by flexible apportionment of three types of care: care aimed at avoiding mental and physical exhaustion, standardized care that does not confer a disadvantage to patients, and immediately responding to prevent problematic behaviors.

  4. Intermittency of the turbulent processes in the Earth's magnetosphere detected from the ground-based measurements

    Energy Technology Data Exchange (ETDEWEB)

    Stepanova, Marina [Physical Department, Universidad de Santiago de Chile (Chile); Foppiano, Alberto; Ovalle, Elias [Departmento de Geofisica, Universidad de Conception (Chile); Antonova, Elizavieta [Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow (Russian Federation); Troshichev, Oleg [Department of Geophysics, Arctic and Antarctic Research Institute, St. Petersburg (Russian Federation)], E-mail: mstepano@usach.cl

    2008-11-01

    Turbulent processes in the Earth's magnetosphere are reflected in the dynamical behavior of the geomagnetic indices and other parameters determined from ground based observations. Intermittent properties of one minute Polar Cap (PC) index and auroral radio wave absorption are studied using 1995-2000 data sets. It was found that the probability distribution functions (PDFs) of both PC-index and absorption fluctuations display a strong non-Gaussian shape. This indicates that they are not characterized by a global time self-similarity but rather exhibit intermittency, as previously reported for solar wind velocity and auroral electrojet index values. In the case of the auroral absorption it was also found that intermittency strongly depends on the magnetic local time, being largest in the nighttime sector. This shows that the acceleration of precipitating particles is intermittent, especially near the substorm eye, where the level of turbulence increases. Application of the Local Intermittency Measure (LIM) technique confirms the aforementioned results to a better precision.

  5. Rupture Process of the 2003 Bam, Iran, Earthquake: Did Shallow Asperities on a Fresh Fault Cause Extreme Ground Motions?

    Science.gov (United States)

    Miyake, H.; Koketsu, K.; Mostafaei, H.

    2004-12-01

    The Bam, Iran, earthquake on December 26, 2003 caused heavy damage to the city of Bam including the historic heritage of Arg-e-Bam. This Mw6.5 earthquake rupture created fresh faults 5 km westward away from the Bam fault. The Bam strong-motion station recorded 992 gal in the UD component and two directivity pulses in the horizontal components with a dominant frequency of 1 Hz. We inferred the rupture process of the 2003 Bam earthquake from strong motion data observed by BHRC, together with teleseismic data to constrain global features of the source. Waveform inversions using teleseismic data (e.g. Yamanaka, 2003; Yagi, 2003) have suggested the existence of a shallow asperity. Nakamura et al. (2004) estimated aftershock distribution with vertical dipping that superimposed the fresh faults, not the Bam fault. They proposed fault planes consisting N-S alignment with northward branches beneath the city of Bam. Our preliminary analyses show that two directivity pulses are created by northward rupture near the hypocenter and north-eastward rupture beneath the city. Recent earthquakes occurred on immature faults with shallow asperities have also generated localized extreme-strong motions (e.g., 2003 Miyagi-ken Hokubu, Japan, with Mw6.1; 2000 Tottori, Japan, with Mw6.6). Larger fracture energy is expected for shallow asperities on immature faults than those on mature faults. For example, the 2000 Tottori earthquake has several times larger fracture energy than expected by the scaling between seismic moment and fracture energy. When considering the energy budget, are radiated energy from the immature faults enough to generate the extreme ground motions? Detailed source process inversions might be able to answer this question.

  6. Sedimentary and water column processes in the Oyster Grounds: a potentially hypoxic region of the North Sea.

    Science.gov (United States)

    Weston, K; Fernand, L; Nicholls, J; Marca-Bell, A; Mills, D; Sivyer, D; Trimmer, M

    2008-04-01

    The purpose of this research was to investigate the potential causes of low oxygen levels in the bottom water of the Oyster Grounds region of the shallow southern North Sea, an area which provides suitable conditions for low oxygen levels to develop. At the end of the summer stratified period, relevant biogeochemical processes were investigated using a combination of sedimentary and water column rate measurements. Phytoplankton nitrate and ammonium uptake was measured throughout the water column using (15)N labelled isotopes and showed ammonium uptake dominated in the upper and bottom mixed layer with a maximum 294.4 micromol N m(-3)h(-1). In the deep chlorophyll maximum at the thermocline, primary production was dominated by nitrate uptake, with an average of 35.0 micromol N m(-3)h(-1), relative to ammonium uptake, with an average of 24.6 micromol N m(-3)h(-1). This high relative nitrate uptake will in part result in exportable new production to the isolated bottom mixed layer and sediments, as opposed to regenerated ammonium driven uptake. This biomass export was indicated by significant benthic oxygen consumption rates in the stratified region (782-1275 micromol O(2)m(-2)h(-1)micromol N m(-3)h(-1)) long after the end of the spring bloom. The sediments were also an active net source of nitrate, ammonium, phosphate and silicate into the bottom mixed layer of 4.4, 8.4, 2.3 and 68.8 micromol m(-2)h(-1), respectively. The export of new production within the thermocline to the bottom mixed layer and the consequent sediment oxygen consumption in the isolated bottom mixed layer in the Oyster Grounds are expected to have contributed to the low bottom water oxygen concentrations of 2.07 mg l(-1) (64.7 micromol l(-1)) measured. The long stratified period associated with this low oxygen is predicted to occur more regularly in the future and continued monitoring of this ecologically important region is therefore essential if the causes of these potentially damaging low

  7. Sill emplacement and corresponding ground deformation processes at the Alu-Dalafilla volcanic centre in the Danakil Depression, Ethiopia

    Science.gov (United States)

    Magee, Craig; Bastow, Ian; Hetherington, Rachel; van Wyk de Vries, Ben; Jackson, Christopher

    2016-04-01

    evaporitic host rock sequence. Important consequences of the shift to sill-dominated magmatism in the Danakil Depression include: (i) roof uplift induced by sill intrusion may not directly relate to the emplaced magma volume if intrusion promotes ductile deformation of the host evaporitic sequence (Schofield et al. 2014), implying that InSAR studies of ground deformation, crucial to volcanic hazard assessment, may under-estimate intruded magma volumes; and (ii) sill volumes are not incorporated into total melt volume estimates, which are used to constrain lithospheric processes active during continental break-up.

  8. Simplified formulae for the estimation of offshore wind turbines clutter on marine radars.

    Science.gov (United States)

    Grande, Olatz; Cañizo, Josune; Angulo, Itziar; Jenn, David; Danoon, Laith R; Guerra, David; de la Vega, David

    2014-01-01

    The potential impact that offshore wind farms may cause on nearby marine radars should be considered before the wind farm is installed. Strong radar echoes from the turbines may degrade radars' detection capability in the area around the wind farm. Although conventional computational methods provide accurate results of scattering by wind turbines, they are not directly implementable in software tools that can be used to conduct the impact studies. This paper proposes a simple model to assess the clutter that wind turbines may generate on marine radars. This method can be easily implemented in the system modeling software tools for the impact analysis of a wind farm in a real scenario.

  9. Detecting Weather Radar Clutter by Information Fusion With Satellite Images and Numerical Weather Prediction Model Output

    DEFF Research Database (Denmark)

    Bøvith, Thomas; Nielsen, Allan Aasbjerg; Hansen, Lars Kai

    2006-01-01

    A method for detecting clutter in weather radar images by information fusion is presented. Radar data, satellite images, and output from a numerical weather prediction model are combined and the radar echoes are classified using supervised classification. The presented method uses indirect...... information on precipitation in the atmosphere from Meteosat-8 multispectral images and near-surface temperature estimates from the DMI-HIRLAM-S05 numerical weather prediction model. Alternatively, an operational nowcasting product called 'Precipitating Clouds' based on Meteosat-8 input is used. A scale...

  10. Measurements and Analysis of Reverberation, Target Echo, and Clutter: FY11 Annual Report for ONR

    Science.gov (United States)

    2011-09-01

    and sonar workshop problems using an adiabatic normal mode model. In Papadakis and Bjørnø [PB11], pages 485–490. Contributed paper in Structured...and clutter data from the Malta Plateau. In Papadakis and Bjørnø [PB11], pages 657–664. Invited paper in Structured Session “Temporal and Spatial...Marigola, Lerici, Italy, 9–12 September 2008. [PB11] John S. Papadakis and Leif Bjørnø, editors. 4th International Conference on Underwater

  11. Measurement of nadir and near-nadir 94-GHz brightness temperatures of several tactical-scene clutter types

    Science.gov (United States)

    Wikner, David A.; Pizzillo, Thomas J.

    1999-07-01

    The authors present 94-GHz radiometric brightness temperatures of various clutter materials at nadir. The clutter materials measured include field vegetation, asphalt pavement, and an asphalt shingle roof and data is presented for each clutter type. We also report measurements that quantify the effect of water on the brightness temperature of metal. These measurements were made by adding calibrated quantities of water to a metal plate while recording the plate's millimeter-wave brightness temperature. Off-nadir data out to 45 deg is also presented for the field vegetation and asphalt pavement. Using a simple rough scattering model for the materials, we made estimates of the emissivity of the field vegetation and asphalt. The emissivity of the roof was determined by measuring its brightness temperature as it was heated.

  12. A Grounded Theory Study of the Process of Accessing Information on the World Wide Web by People with Mild Traumatic Brain Injury

    Science.gov (United States)

    Blodgett, Cynthia S.

    2008-01-01

    The purpose of this grounded theory study was to examine the process by which people with Mild Traumatic Brain Injury (MTBI) access information on the web. Recent estimates include amateur sports and recreation injuries, non-hospital clinics and treatment facilities, private and public emergency department visits and admissions, providing…

  13. Modeling the inactivatin of Escherichia coli 0157:H7 and uropathogenic E. coli in ground beef by high pressure processing and citral

    Science.gov (United States)

    Disease causing Escherichia coli commonly found in meat and poultry include intestinal pathogenic E. coli (iPEC) as well as extraintestinal types such as the Uropathogenic E. coli (UPEC). In this study we compared the resistance of iPEC (O157:H7) to UPEC in ground beef using High Pressure Processing...

  14. Multiwaveband simulation-based signature analysis of camouflaged human dismounts in cluttered environments with TAIThermIR and MuSES

    Science.gov (United States)

    Packard, Corey D.; Klein, Mark D.; Viola, Timothy S.; Hepokoski, Mark A.

    2016-10-01

    The ability to predict electro-optical (EO) signatures of diverse targets against cluttered backgrounds is paramount for signature evaluation and/or management. Knowledge of target and background signatures is essential for a variety of defense-related applications. While there is no substitute for measured target and background signatures to determine contrast and detection probability, the capability to simulate any mission scenario with desired environmental conditions is a tremendous asset for defense agencies. In this paper, a systematic process for the thermal and visible-through-infrared simulation of camouflaged human dismounts in cluttered outdoor environments is presented. This process, utilizing the thermal and EO/IR radiance simulation tool TAIThermIR (and MuSES), provides a repeatable and accurate approach for analyzing contrast, signature and detectability of humans in multiple wavebands. The engineering workflow required to combine natural weather boundary conditions and the human thermoregulatory module developed by ThermoAnalytics is summarized. The procedure includes human geometry creation, human segmental physiology description and transient physical temperature prediction using environmental boundary conditions and active thermoregulation. Radiance renderings, which use Sandford-Robertson BRDF optical surface property descriptions and are coupled with MODTRAN for the calculation of atmospheric effects, are demonstrated. Sensor effects such as optical blurring and photon noise can be optionally included, increasing the accuracy of detection probability outputs that accompany each rendering. This virtual evaluation procedure has been extensively validated and provides a flexible evaluation process that minimizes the difficulties inherent in human-subject field testing. Defense applications such as detection probability assessment, camouflage pattern evaluation, conspicuity tests and automatic target recognition are discussed.

  15. Modeling and Analysis of Target Echo and Clutter in Range-Dependent Bistatic Environments: FY12 Annual Report for ONR

    Science.gov (United States)

    2012-09-30

    and sonar workshop problems using an adiabatic normal mode model. In Papadakis and Bjørnø [PB11], pages 485–490. Contributed paper in Structured...Clutter Model: Range-dependent predictions compared with towed array reverberation and clutter data from the Malta Plateau. In Papadakis and Bjørnø...35(3):502–515, 2010. 10 [PB11] John S. Papadakis and Leif Bjørnø, editors. 4th International Conference on Underwater Acoustic Measurements

  16. Numerical simulation of the process of geothermal low-potential ground energy extraction in Perm region (Russia

    Directory of Open Access Journals (Sweden)

    Ponomaryov Andrey

    2016-01-01

    Full Text Available The aim of our research is to study the interaction of energy foundations with the ground mass and to develop methods for their construction on the example of the city of Perm. Field studies of ground were carried out in a specially chosen pilot site to determine temperature distribution in the ground mass, change of ground-water level and physical-mechanical and thermal-physical characteristics of the ground mass. The diagrams of depth temperature distribution in the ground and its seasonal variations were obtained on the results of monitoring, and also the average groundwater level. To carry out numerical simulation, software-complex “GeoStudio” was selected. Its basic differential equation is the fundamental heat conduction equation with an internal heat source. The purpose of the numerical simulation was quantitative evaluation of the thermal energy extracted from different energy foundations under soil conditions in the city of Perm. By results of the spent numerical experiments the equations of regress and nomographs dependences of size of received thermal energy on geometrical parameters of the projected power bases to hydro-geological and climatic conditions of the Perm region are constructed.

  17. Big brown bats (Eptesicus fuscus) reveal diverse strategies for sonar target tracking in clutter.

    Science.gov (United States)

    Mao, Beatrice; Aytekin, Murat; Wilkinson, Gerald S; Moss, Cynthia F

    2016-09-01

    Bats actively adjust the acoustic features of their sonar calls to control echo information specific to a given task and environment. A previous study investigated how bats adapted their echolocation behavior when tracking a moving target in the presence of a stationary distracter at different distances and angular offsets. The use of only one distracter, however, left open the possibility that a bat could reduce the interference of the distracter by turning its head. Here, bats tracked a moving target in the presence of one or two symmetrically placed distracters to investigate adaptive echolocation behavior in a situation where vocalizing off-axis would result in increased interference from distracter echoes. Both bats reduced bandwidth and duration but increased sweep rate in more challenging distracter conditions, and surprisingly, made more head turns in the two-distracter condition compared to one, but only when distracters were placed at large angular offsets. However, for most variables examined, subjects showed distinct strategies to reduce clutter interference, either by (1) changing spectral or temporal features of their calls, or (2) producing large numbers of sonar sound groups and consistent head-turning behavior. The results suggest that individual bats can use different strategies for target tracking in cluttered environments.

  18. Radar signatures of indoor clutter for through-the-wall radar applications

    Science.gov (United States)

    Bufler, Travis D.; Narayanan, Ram M.; Dogaru, Traian

    2014-05-01

    In through-the-wall radar (TTWR) applications, scattering by indoor clutter elements can greatly confound the detection of humans. This paper analyzes the spectral and azimuthal scattering characteristics of various types of individual furniture targets and compares these to humans. Radar cross section (RCS) values of furniture and humans are obtained using the finite difference time domain (FDTD) technique over the 1-5 GHz frequency range and the 0-360 azimuth angle range for both co- and cross-polarized scattering. In the case of furniture, RCS responses show to the highest returns when viewing the planar surfaces of the clutter objects. Objects consisting primarily of smaller planar surfaces with more complex geometrical features showed a more uniform response with no preferred orientation showing a larger response. Human RCS produced from the biological models showed a more constant RCS when viewing the co-polarized response, where the back produced the highest response due to the more planar surface. The cross-polarized response was more varied providing for a wider range of RCS values.

  19. The estimation of lower refractivity uncertainty from radar sea clutter using the Bayesian-MCMC method

    Institute of Scientific and Technical Information of China (English)

    Sheng Zheng

    2013-01-01

    The estimation of lower atmospheric refractivity from radar sea clutter (RFC) is a complicated nonlinear optimization problem.This paper deals with the RFC problem in a Bayesian framework.It uses the unbiased Markov Chain Monte Carlo (MCMC) sampling technique,which can provide accurate posterior probability distributions of the estimated refractivity parameters by using an electromagnetic split-step fast Fourier transform terrain parabolic equation propagation model within a Bayesian inversion framework.In contrast to the global optimization algorithm,the Bayesian-MCMC can obtain not only the approximate solutions,but also the probability distributions of the solutions,that is,uncertainty analyses of solutions.The Bayesian-MCMC algorithm is implemented on the simulation radar sea-clutter data and the real radar seaclutter data.Reference data are assumed to be simulation data and refractivity profiles are obtained using a helicopter.The inversion algorithm is assessed (i) by comparing the estimated refractivity profiles from the assumed simulation and the helicopter sounding data; (ii) the one-dimensional (1D) and two-dimensional (2D) posterior probability distribution of solutions.

  20. Spatial memory and stereotypy of flight paths by big brown bats in cluttered surroundings.

    Science.gov (United States)

    Barchi, Jonathan R; Knowles, Jeffrey M; Simmons, James A

    2013-03-15

    The big brown bat, Eptesicus fuscus, uses echolocation for foraging and orientation. The limited operating range of biosonar implies that bats must rely upon spatial memory in familiar spaces with dimensions larger than a few meters. Prior experiments with bats flying in obstacle arrays have revealed differences in flight and acoustic emission patterns depending on the density and spatial extent of the obstacles. Using the same method, combined with acoustic microphone array tracking, we flew big brown bats in an obstacle array that varied in density and distribution in different locations in the flight room. In the initial experiment, six bats learned individually stereotyped flight patterns as they became familiar with the space. After the first day, the repetition rate of sonar broadcasts dropped to a stable level, consistent with low-density clutter. In a second experiment, after acquiring their stable paths, each bat was released from each of two unfamiliar locations in the room. Each bat still followed the same flight path it learned originally. In a third experiment, performed 1 month after the first two experiments, three of the bats were re-flown in the same configuration of obstacles; these three resumed flying in their accustomed path. The other three bats were flown in a mirror-image reconfiguration of the obstacles; these bats quickly found stable flight paths that differed from their originally learned paths. Overall, the flight patterns indicate that the bats perceive the cluttered space as a single scene through which they develop globally organized flight paths.

  1. Coordinate-Based Clustering Method for Indoor Fingerprinting Localization in Dense Cluttered Environments

    Directory of Open Access Journals (Sweden)

    Wen Liu

    2016-12-01

    Full Text Available Indoor positioning technologies has boomed recently because of the growing commercial interest in indoor location-based service (ILBS. Due to the absence of satellite signal in Global Navigation Satellite System (GNSS, various technologies have been proposed for indoor applications. Among them, Wi-Fi fingerprinting has been attracting much interest from researchers because of its pervasive deployment, flexibility and robustness to dense cluttered indoor environments. One challenge, however, is the deployment of Access Points (AP, which would bring a significant influence on the system positioning accuracy. This paper concentrates on WLAN based fingerprinting indoor location by analyzing the AP deployment influence, and studying the advantages of coordinate-based clustering compared to traditional RSS-based clustering. A coordinate-based clustering method for indoor fingerprinting location, named Smallest-Enclosing-Circle-based (SEC, is then proposed aiming at reducing the positioning error lying in the AP deployment and improving robustness to dense cluttered environments. All measurements are conducted in indoor public areas, such as the National Center For the Performing Arts (as Test-bed 1 and the XiDan Joy City (Floors 1 and 2, as Test-bed 2, and results show that SEC clustering algorithm can improve system positioning accuracy by about 32.7% for Test-bed 1, 71.7% for Test-bed 2 Floor 1 and 73.7% for Test-bed 2 Floor 2 compared with traditional RSS-based clustering algorithms such as K-means.

  2. Tracking a maneuvering target in clutter with out-of-sequence measurements for airborne radar

    Institute of Scientific and Technical Information of China (English)

    Weihua Wu; Jing Jiang; Yang Wan

    2015-01-01

    There are many proposed optimal or suboptimal al-gorithms to update out-of-sequence measurement(s) (OoSM(s)) for linear-Gaussian systems, but few algorithms are dedicated to track a maneuvering target in clutter by using OoSMs. In order to address the nonlinear OoSMs obtained by the airborne radar located on a moving platform from a maneuvering target in clut-ter, an interacting multiple model probabilistic data association (IMMPDA) algorithm with the OoSM is developed. To be practical, the algorithm is based on the Earth-centered Earth-fixed (ECEF) coordinate system where it considers the effect of the platform’s attitude and the curvature of the Earth. The proposed method is validated through the Monte Carlo test compared with the perfor-mance of the standard IMMPDA algorithm ignoring the OoSM, and the conclusions show that using the OoSM can improve the track-ing performance, and the shorter the lag step is, the greater degree the performance is improved, but when the lag step is large, the performance is not improved any more by using the OoSM, which can provide some references for engineering application.

  3. 3-D Laser-Based Multiclass and Multiview Object Detection in Cluttered Indoor Scenes.

    Science.gov (United States)

    Zhang, Xuesong; Zhuang, Yan; Hu, Huosheng; Wang, Wei

    2017-01-01

    This paper investigates the problem of multiclass and multiview 3-D object detection for service robots operating in a cluttered indoor environment. A novel 3-D object detection system using laser point clouds is proposed to deal with cluttered indoor scenes with a fewer and imbalanced training data. Raw 3-D point clouds are first transformed to 2-D bearing angle images to reduce the computational cost, and then jointly trained multiple object detectors are deployed to perform the multiclass and multiview 3-D object detection. The reclassification technique is utilized on each detected low confidence bounding box in the system to reduce false alarms in the detection. The RUS-SMOTEboost algorithm is used to train a group of independent binary classifiers with imbalanced training data. Dense histograms of oriented gradients and local binary pattern features are combined as a feature set for the reclassification task. Based on the dalian university of technology (DUT)-3-D data set taken from various office and household environments, experimental results show the validity and good performance of the proposed method.

  4. Phase-modulated waveform design for extended target detection in the presence of clutter.

    Science.gov (United States)

    Gong, Xuhua; Meng, Huadong; Wei, Yimin; Wang, Xiqin

    2011-01-01

    The problem to be addressed in this paper is a phase-modulated waveform design for the detection of extended targets contaminated by signal-dependent noise (clutter) and additive noise in practical radar systems. An optimal waveform design method that leads to the energy spectral density (ESD) of signal under the maximum signal-to-clutter-and-noise ratio (SCNR) criterion is introduced first. In order to make full use of the transmission power, a novel phase-iterative algorithm is then proposed for designing the phase-modulated waveform with a constant envelope, whose ESD matches the optimal one. This method is proven to be able to achieve a small SCNR loss by minimizing the mean-square spectral distance between the optimal waveform and the designed waveform. The results of extensive simulations demonstrate that our approach provides less than 1 dB SCNR loss when the signal duration is greater than 1 μs, and outperforms the stationary phase method and other phase-modulated waveform design methods.

  5. Coordinate-Based Clustering Method for Indoor Fingerprinting Localization in Dense Cluttered Environments.

    Science.gov (United States)

    Liu, Wen; Fu, Xiao; Deng, Zhongliang

    2016-12-02

    Indoor positioning technologies has boomed recently because of the growing commercial interest in indoor location-based service (ILBS). Due to the absence of satellite signal in Global Navigation Satellite System (GNSS), various technologies have been proposed for indoor applications. Among them, Wi-Fi fingerprinting has been attracting much interest from researchers because of its pervasive deployment, flexibility and robustness to dense cluttered indoor environments. One challenge, however, is the deployment of Access Points (AP), which would bring a significant influence on the system positioning accuracy. This paper concentrates on WLAN based fingerprinting indoor location by analyzing the AP deployment influence, and studying the advantages of coordinate-based clustering compared to traditional RSS-based clustering. A coordinate-based clustering method for indoor fingerprinting location, named Smallest-Enclosing-Circle-based (SEC), is then proposed aiming at reducing the positioning error lying in the AP deployment and improving robustness to dense cluttered environments. All measurements are conducted in indoor public areas, such as the National Center For the Performing Arts (as Test-bed 1) and the XiDan Joy City (Floors 1 and 2, as Test-bed 2), and results show that SEC clustering algorithm can improve system positioning accuracy by about 32.7% for Test-bed 1, 71.7% for Test-bed 2 Floor 1 and 73.7% for Test-bed 2 Floor 2 compared with traditional RSS-based clustering algorithms such as K-means.

  6. Phase-Modulated Waveform Design for Extended Target Detection in the Presence of Clutter

    Directory of Open Access Journals (Sweden)

    Xiqin Wang

    2011-07-01

    Full Text Available The problem to be addressed in this paper is a phase-modulated waveform design for the detection of extended targets contaminated by signal-dependent noise (clutter and additive noise in practical radar systems. An optimal waveform design method that leads to the energy spectral density (ESD of signal under the maximum signal-to-clutter-and-noise ratio (SCNR criterion is introduced first. In order to make full use of the transmission power, a novel phase-iterative algorithm is then proposed for designing the phase-modulated waveform with a constant envelope, whose ESD matches the optimal one. This method is proven to be able to achieve a small SCNR loss by minimizing the mean-square spectral distance between the optimal waveform and the designed waveform. The results of extensive simulations demonstrate that our approach provides less than 1 dB SCNR loss when the signal duration is greater than 1 μs, and outperforms the stationary phase method and other phase-modulated waveform design methods.

  7. Simulating the thermal regime and thaw processes of ice-rich permafrost ground with the land-surface model CryoGrid 3

    Science.gov (United States)

    Westermann, S.; Langer, M.; Boike, J.; Heikenfeld, M.; Peter, M.; Etzelmüller, B.; Krinner, G.

    2016-02-01

    Thawing of permafrost in a warming climate is governed by a complex interplay of different processes of which only conductive heat transfer is taken into account in most model studies. However, observations in many permafrost landscapes demonstrate that lateral and vertical movement of water can have a pronounced influence on the thaw trajectories, creating distinct landforms, such as thermokarst ponds and lakes, even in areas where permafrost is otherwise thermally stable. Novel process parameterizations are required to include such phenomena in future projections of permafrost thaw and subsequent climatic-triggered feedbacks. In this study, we present a new land-surface scheme designed for permafrost applications, CryoGrid 3, which constitutes a flexible platform to explore new parameterizations for a range of permafrost processes. We document the model physics and employed parameterizations for the basis module CryoGrid 3, and compare model results with in situ observations of surface energy balance, surface temperatures, and ground thermal regime from the Samoylov permafrost observatory in NE Siberia. The comparison suggests that CryoGrid 3 can not only model the evolution of the ground thermal regime in the last decade, but also consistently reproduce the chain of energy transfer processes from the atmosphere to the ground. In addition, we demonstrate a simple 1-D parameterization for thaw processes in permafrost areas rich in ground ice, which can phenomenologically reproduce both formation of thermokarst ponds and subsidence of the ground following thawing of ice-rich subsurface layers. Long-term simulation from 1901 to 2100 driven by reanalysis data and climate model output demonstrate that the hydrological regime can both accelerate and delay permafrost thawing. If meltwater from thawed ice-rich layers can drain, the ground subsides, as well as the formation of a talik, are delayed. If the meltwater pools at the surface, a pond is formed that enhances heat

  8. Curvelet filter based prescreener for explosive hazard detection in hand-held ground penetrating radar

    Science.gov (United States)

    White, Julie L.; Anderson, Derek T.; Ball, John E.; Parker, Brian

    2016-05-01

    Explosive hazards, above and below ground, are a serious threat to civilians and soldiers. In an attempt to mitigate these threats, different forms of explosive hazard detection (EHD) exist; e.g., multi-sensor hand-held platforms, downward looking and forward looking vehicle mounted platforms, etc. Robust detection of these threats resides in the processing and fusion of different data from multiple sensing modalities, e.g., radar, infrared, electromagnetic induction (EMI), etc. Herein, we focus on a new energy-based prescreener in hand-held ground penetrating radar (GPR). First, we Curvelet filter B-scan signal data using either Reverse-Reconstruction followed by Enhancement (RRE) or selectivity with respect to wedge information in the Curvelet transform. Next, we aggregate the result of a bank of matched filters and run a size contrast filter with Bhattacharyya distance. Alarms are then combined using weighted mean shift clustering. Results are demonstrated in the context of receiver operating characteristics (ROC) curve performance on data from a U. S. Army test site that contains multiple target and clutter types, burial depths and times of the day.

  9. Ground Penetrating Radar Field Studies of Lunar-Analog Geologic Settings and Processes: Barringer Meteor Crater and Northern Arizona Volcanics

    Science.gov (United States)

    Russell, P. S.; Grant, J. A.; Williams, K. K.; Bussey, B.

    2010-12-01

    Ground-Penetrating Radar (GPR) data from terrestrial analog environments can help constrain models for evolution of the lunar surface, aid in interpretation of orbital SAR data, and help predict what might be encountered in the subsurface during future, landed, scientific or engineering operations on the Moon. GPR can yield insight into the physical properties, clast-size distribution, and layering of the subsurface, granting a unique view of the processes affecting an area over geologic time. The purpose of our work is to demonstrate these capabilities at sites at which geologic processes, settings, and/or materials are similar to those that may be encountered on the moon, especially lava flows, impact-crater ejecta, and layered materials with varying properties. We present results from transects obtained at Barringer Meteor Crater, SP Volcano cinder cone, and Sunset Crater Volcano National Monument, all in northern Arizona. Transects were taken at several sites on the ejecta of Meteor Crater, all within a crater radius (~400 m) of the crater rim. Those taken across ejecta lobes or mounds reveal the subsurface contact of the ejecta upper surface and overlying, embaying sediments deposited by later alluvial, colluvial, and/or aeolian processes. Existing mine shafts and pits on the south side of the crater provide cross sections of the subsurface against which we compare adjacent GPR transects. The ‘actual’ number, size, and depth of clasts in the top 1-2 m of the subsurface are estimated from photos of the exposed cross sections. In GPR radargrams, reflections attributed to blocks in the top 2-5 m of the subsurface are counted, and their depth distribution noted. Taking GPR measurements along a transect at two frequencies (200 and 400 MHz) and to various depths, we obtain the ratio of the actual number of blocks in the subsurface to the number detectable with GPR, as well as an assessment of how GPR detections in ejecta decline with depth and depend on antenna

  10. A single-ensemble clutter rejection method based on the analytic geometry for ultrasound color flow imaging.

    Science.gov (United States)

    You, Wei; Wang, Yuanyuan

    2011-11-01

    In ultrasound color flow imaging (CFI), the single-ensemble eigen-based filters can reject clutter components using each slow-time ensemble individually. They have shown excellent spatial adaptability. This article proposes a novel clutter rejection method called the single-ensemble geometry filter (SGF), which is derived from an analytic geometry perspective. If the transmitted pulse number M equals two, the clutter component distribution on a two-dimensional (2-D) plane will be similar to a tilted ellipse. Therefore, the direction of the major axis of the ellipse can be used as the first principal component of the autocorrelation matrix estimated from multiple ensembles. Then the algorithm is generalized from 2-D to a higher dimensional space by using linear algebra representations of the ellipse. Comparisons have been made with the high-pass filter (HPF), the Hankel-singular value decomposition (SVD) filter and the recursive eigen-decomposition (RED) method using both simulated and human carotid data. Results show that compared with HPF and Hankel-SVD, the proposed filter causes less bias on the velocity estimation when the clutter velocity is close to that of the blood flow. On the other hand, the proposed filter does not need to update the autocorrelation matrix and can achieve better spatial adaptability than the RED.

  11. Using acoustic sensor technologies to create a more terrain capable unmanned ground vehicle

    OpenAIRE

    Odedra, Sid; Prior, Stephen D.; Karamanoglu, Mehmet; Erbil, Mehmet Ali; Shen, Siu-Tsen; International Conference on Engineering Psychology and Cognitive Ergonomics

    2009-01-01

    Unmanned Ground Vehicle’s (UGV) have to cope with the most complex range of dynamic and variable obstacles and therefore need to be highly intelligent in order to cope with navigating in such a cluttered environment. When traversing over different terrains (whether it is a UGV or a commercial manned vehicle) different drive styles and configuration settings need to be selected in order to travel successfully over each terrain type. These settings are usually selected by a human operator in ma...

  12. Full-wave modelling of ground-penetrating radars: antenna mutual coupling phenomena and sub-surface scattering processes

    NARCIS (Netherlands)

    Caratelli, D.; Yarovoy, A.

    2011-01-01

    Ground-penetrating radar (GPR) technology finds applications in many areas such as geophysical prospecting, archaeology, civil engineering, environmental engineering, and defence applications as a non-invasive sensing tool [3], [6], [18]. One key component in any GPR system is the receiver/transmitt

  13. Ground-water flow and contaminant transport at a radioactive-materials processing site, Wood River Junction, Rhode Island

    Science.gov (United States)

    Ryan, Barbara J.; Kipp, Kenneth L.

    1997-01-01

    Liquid wastes from an enriched-uranium cold-scrap recovery plant at Wood River Junction, Rhode Island, were discharged to the environment through evaporation ponds and trenches from 1966 through 1980. Leakage from the ponds and trenches resulted in a plume of contaminated ground water extending northwestward to the Pawcatuck River through a highly permeable sand and gravel aquifer of glacial origin.

  14. Clutter Modeling of Airborne MIMO Radar Based on CUDA%基于CUDA的机载MIMO雷达杂波建模

    Institute of Scientific and Technical Information of China (English)

    王占广; 罗忠涛; 李军; 孙颖

    2011-01-01

    针对机载MIMO雷达杂波模型运算量大的问题,建立了基于CUDA的模型,利用图形处理器的并行运算能力来加速运算。为了符合CUDA的通用计算架构特性,该模型在算法上优先设计并行运算,在编程上尽量引入并行线程,实现图形处理器的浮点运算、存储器以及带宽资源的有效利用。最后测试了加速效果与模型结构、数据规模的关系。实验结果表明,与CPUInteli5750比较。图形处理器Grrx465的建模运算结果准确.效率提升教十倍.能麦特委大的运算号.%Considering big operand problem of clutter model for airborne MIMO radar, a clutter based on Compute Unified Device Architecture (CUDA) is established and operation is speeded up by using parallel operational capa- bility of Graphic Processing Unit(GPU). In order to accord with general computation architecture characteristic of CUPD, the new model prefers designing parallel computing in algorithm and introducing parallel threads in programming to implement effective usage of floating point operation, storage and wideband resources of GPU. And finally, relation between the speedup effect and model architecture and data size is tested. The tested results prove that modeling computation result of GPU based on GTX 465 is accurate in computing result, and efficiency is increased by tens of times and bigger operand can be supported comparing with CPUIntel i5 750.

  15. OPTIMAL SELECTION OF THE CA-CFAR ADJUSTMENT FACTOR FOR K POWER SEA CLUTTER WITH STATISTICAL VARIATIONS

    Directory of Open Access Journals (Sweden)

    José Raúl Machado Fernández

    2017-01-01

    Full Text Available La presencia de la señal interferente de clutter marino establece limitaciones en la calidad de la detección de radar en ambientes costeros y de alta mar. El procesador CA-CFAR es la solución clásica para detectar blancos de radar. Usualmente mantiene su factor de ajuste constante todo el período de operación. Como consecuencia, el esquema no toma en consideración las variaciones estadísticas de la señal de fondo cuando realiza la discriminación del clutter . Para resolver este problema, los autores realizaron un procesamiento intensivo de 40 millones de muestras de clutter de intensidad, generadas en computadora a través de MATLAB. Como resultado, encontraron los valores óptimos del factor de ajuste a ser aplicados para 40 posibles estados estadísticos del clutter , sugiriendo el uso de la arquitectura CA-CFAR con un factor de ajuste variable. Adicionalmente, fue llevado a cabo un ajuste de curvas, obteniéndose expresiones matemáticas que generalizan los resultados en todo el intervalo de considerado de estados estadísticos del clutter . Los experimentos se ejecutaron con un CA-CFAR de 64 celdas y apuntaron a encontrar los valores del factor de ajuste para tres probabilidades de falsa alarma comunes. La distribución K fue elegida como el modelo usado para el clutter , gracias a su amplia popularidad. Este artículo facilita el manejo de la distribución K de intensidad, evitando el uso de funciones Gamma y Bessel, comúnmente encontradas en desarrollos relacionados con el modelo K. Además, fueron cumplidos los requerimientos necesarios para construir un detector adaptativo en clutter de potencia K con conocimiento previo del parámetro de forma. Al mismo tiempo, fueron dadas varias recomendaciones para continuar el desarrollo de una solución más general que también incluirá la estimación del parámetro de forma.

  16. Design of a Free and Open Source Data Processing, Archiving, and Distribution Subsystem for the Ground Receiving Station of the Philippine Scientific Earth Observation Micro-Satellite

    Science.gov (United States)

    Aranas, R. K. D.; Jiao, B. J. D.; Magallon, B. J. P.; Ramos, M. K. F.; Amado, J. A.; Tamondong, A. M.; Tupas, M. E. A.

    2016-06-01

    The Philippines's PHL-Microsat program aims to launch its first earth observation satellite, DIWATA, on the first quarter of 2016. DIWATA's payload consists of a high-precision telescope (HPT), spaceborne multispectral imager (SMI) with liquid crystal tunable filter (LCTF), and a wide field camera (WFC). Once launched, it will provide information about the Philippines, both for disaster and environmental applications. Depending on the need, different remote sensing products will be generated from the microsatellite sensors. This necessitates data processing capability on the ground control segment. Rather than rely on commercial turnkey solutions, the PHL-Microsat team, specifically Project 3:DPAD, opted to design its own ground receiving station data subsystems. This paper describes the design of the data subsystems of the ground receiving station (GRS) for DIWATA. The data subsystems include: data processing subsystem for automatic calibration and georeferencing of raw images as well as the generation of higher level processed data products; data archiving subsystem for storage and backups of both raw and processed data products; and data distribution subsystem for providing a web-based interface and product download facility for the user community. The design covers the conceptual design of the abovementioned subsystems, the free and open source software (FOSS) packages used to implement them, and the challenges encountered in adapting the existing FOSS packages to DIWATA GRS requirements.

  17. DESIGN OF A FREE AND OPEN SOURCE DATA PROCESSING, ARCHIVING, AND DISTRIBUTION SUBSYSTEM FOR THE GROUND RECEIVING STATION OF THE PHILIPPINE SCIENTIFIC EARTH OBSERVATION MICRO-SATELLITE

    Directory of Open Access Journals (Sweden)

    R. K. D. Aranas

    2016-06-01

    Full Text Available The Philippines’s PHL-Microsat program aims to launch its first earth observation satellite, DIWATA, on the first quarter of 2016. DIWATA’s payload consists of a high-precision telescope (HPT, spaceborne multispectral imager (SMI with liquid crystal tunable filter (LCTF, and a wide field camera (WFC. Once launched, it will provide information about the Philippines, both for disaster and environmental applications. Depending on the need, different remote sensing products will be generated from the microsatellite sensors. This necessitates data processing capability on the ground control segment. Rather than rely on commercial turnkey solutions, the PHL-Microsat team, specifically Project 3:DPAD, opted to design its own ground receiving station data subsystems. This paper describes the design of the data subsystems of the ground receiving station (GRS for DIWATA. The data subsystems include: data processing subsystem for automatic calibration and georeferencing of raw images as well as the generation of higher level processed data products; data archiving subsystem for storage and backups of both raw and processed data products; and data distribution subsystem for providing a web-based interface and product download facility for the user community. The design covers the conceptual design of the abovementioned subsystems, the free and open source software (FOSS packages used to implement them, and the challenges encountered in adapting the existing FOSS packages to DIWATA GRS requirements.

  18. Statistical Signal Processing in Humanitarian Mine Clerance Systems

    DEFF Research Database (Denmark)

    Karlsen, Brian; Sørensen, Helge Bjarup Dissing; Larsen, Jan;

    2002-01-01

    Denne artikel beskriver kortfattet metoder og resultater relateret til clutterreduktion (clutter: uønskede reflekterede signaler) i jordradar- (eng. ground penetrating radar, GPR) signaler vha. statistiske signalbehandlingsmetoder baseret på Independent Component Analysis (ICA). Formålet ved denn...

  19. Real-time Gaussian Markov random-field-based ground tracking for ground penetrating radar data

    Science.gov (United States)

    Bradbury, Kyle; Torrione, Peter A.; Collins, Leslie

    2009-05-01

    Current ground penetrating radar algorithms for landmine detection require accurate estimates of the location of the air/ground interface to maintain high levels of performance. However, the presence of surface clutter, natural soil roughness, and antenna motion lead to uncertainty in these estimates. Previous work on improving estimates of the location of the air/ground interface have focused on one-dimensional filtering techniques to localize the air/ground interface. In this work, we propose an algorithm for interface localization using a 2- D Gaussian Markov random field (GMRF). The GMRF provides a statistical model of the surface structure, which enables the application of statistical optimization techniques. In this work, the ground location is inferred using iterated conditional modes (ICM) optimization which maximizes the conditional pseudo-likelihood of the GMRF at a point, conditioned on its neighbors. To illustrate the efficacy of the proposed interface localization approach, pre-screener performance with and without the proposed ground localization algorithm is compared. We show that accurate localization of the air/ground interface provides the potential for future performance improvements.

  20. An X-ray scatter system for material identification in cluttered objects: A Monte Carlo simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Lakshmanan, Manu N. [Ravin Advanced Imaging Laboratories, Dept. of Radiology, Duke University Medical Center, Durham, NC (United States); Kapadia, Anuj J., E-mail: anuj.kapadia@duke.edu [Ravin Advanced Imaging Laboratories, Dept. of Radiology, Duke University Medical Center, Durham, NC (United States); Sahbaee, Pooyan [Ravin Advanced Imaging Laboratories, Dept. of Radiology, Duke University Medical Center, Durham, NC (United States); Dept. of Physics, NC State University, Raleigh, NC (United States); Wolter, Scott D. [Dept. of Physics, Elon University, Elon, NC (United States); Harrawood, Brian P. [Ravin Advanced Imaging Laboratories, Dept. of Radiology, Duke University Medical Center, Durham, NC (United States); Brady, David [Dept. of Electrical and Computer Engineering, Duke University, Durham, NC (United States); Samei, Ehsan [Ravin Advanced Imaging Laboratories, Dept. of Radiology, Duke University Medical Center, Durham, NC (United States); Dept. of Electrical and Computer Engineering, Duke University, Durham, NC (United States)

    2014-09-15

    The analysis of X-ray scatter patterns has been demonstrated as an effective method of identifying specific materials in mixed object environments, for both biological and non-biological applications. Here we describe an X-ray scatter imaging system for material identification in cluttered objects and investigate its performance using a large-scale Monte Carlo simulation study of one-thousand objects containing a broad array of materials. The GEANT4 Monte Carlo source code for Rayleigh scatter physics was modified to model coherent scatter diffraction in bulk materials based on experimentally measured form factors for 33 materials. The simulation was then used to model coherent scatter signals from a variety of targets and clutter (background) materials in one thousand randomized objects. The resulting scatter images were used to characterize four parameters of the imaging system that affected its ability to identify target materials: (a) the arrangement of materials in the object, (b) clutter attenuation, (c) type of target material, and (d) the X-ray tube current. We found that the positioning of target materials within the object did not significantly affect their detectability; however, a strong negative correlation was observed between the target detectability and the clutter attenuation of the object. The imaging signal was also found to be relatively invariant to increases in X-ray tube current above 1 mAs for most materials considered in the study. This work is the first Monte Carlo study to our knowledge of a large population of cluttered object of an X-ray scatter imaging system for material identification and lays the foundation for large-scale studies of the effectiveness of X-ray scatter imaging systems for material identification in complex samples.

  1. An X-ray scatter system for material identification in cluttered objects: A Monte Carlo simulation study

    Science.gov (United States)

    Lakshmanan, Manu N.; Kapadia, Anuj J.; Sahbaee, Pooyan; Wolter, Scott D.; Harrawood, Brian P.; Brady, David; Samei, Ehsan

    2014-09-01

    The analysis of X-ray scatter patterns has been demonstrated as an effective method of identifying specific materials in mixed object environments, for both biological and non-biological applications. Here we describe an X-ray scatter imaging system for material identification in cluttered objects and investigate its performance using a large-scale Monte Carlo simulation study of one-thousand objects containing a broad array of materials. The GEANT4 Monte Carlo source code for Rayleigh scatter physics was modified to model coherent scatter diffraction in bulk materials based on experimentally measured form factors for 33 materials. The simulation was then used to model coherent scatter signals from a variety of targets and clutter (background) materials in one thousand randomized objects. The resulting scatter images were used to characterize four parameters of the imaging system that affected its ability to identify target materials: (a) the arrangement of materials in the object, (b) clutter attenuation, (c) type of target material, and (d) the X-ray tube current. We found that the positioning of target materials within the object did not significantly affect their detectability; however, a strong negative correlation was observed between the target detectability and the clutter attenuation of the object. The imaging signal was also found to be relatively invariant to increases in X-ray tube current above 1 mAs for most materials considered in the study. This work is the first Monte Carlo study to our knowledge of a large population of cluttered object of an X-ray scatter imaging system for material identification and lays the foundation for large-scale studies of the effectiveness of X-ray scatter imaging systems for material identification in complex samples.

  2. Towards automatic indoor reconstruction of cluttered building rooms from point clouds

    Science.gov (United States)

    Previtali, M.; Barazzetti, L.; Brumana, R.; Scaioni, M.

    2014-05-01

    Terrestrial laser scanning is increasingly used in architecture and building engineering for as-built modelling of large and medium size civil structures. However, raw point clouds derived from laser scanning survey are generally not directly ready for generation of such models. A manual modelling phase has to be undertaken to edit and complete 3D models, which may cover indoor or outdoor environments. This paper presents an automated procedure to turn raw point clouds into semantically-enriched models of building interiors. The developed method mainly copes with a geometric complexity typical of indoor scenes with prevalence of planar surfaces, such as walls, floors and ceilings. A characteristic aspect of indoor modelling is the large amount of clutter and occlusion that may characterize any point clouds. For this reason the developed reconstruction pipeline was designed to recover and complete missing parts in a plausible way. The accuracy of the presented method was evaluated against traditional manual modelling and showed comparable results.

  3. Radar Constant-Modulus Waveform Design with Prior Information of the Extended Target and Clutter.

    Science.gov (United States)

    Yue, Wenzhen; Zhang, Yan; Liu, Yimin; Xie, Jingwen

    2016-06-17

    Radar waveform design is of great importance for radar system performances and has drawn considerable attention recently. Constant modulus is an important waveform design consideration, both from the point of view of hardware realization and to allow for full utilization of the transmitter's power. In this paper, we consider the problem of constant-modulus waveform design for extended target detection with prior information about the extended target and clutter. At first, we propose an arbitrary-phase unimodular waveform design method via joint transmitter-receiver optimization. We exploit a semi-definite relaxation technique to transform an intractable non-convex problem into a convex problem, which can then be efficiently solved. Furthermore, quadrature phase shift keying waveform is designed, which is easier to implement than arbitrary-phase waveforms. Numerical results demonstrate the effectiveness of the proposed methods.

  4. [Introduction to grounded theory].

    Science.gov (United States)

    Wang, Shou-Yu; Windsor, Carol; Yates, Patsy

    2012-02-01

    Grounded theory, first developed by Glaser and Strauss in the 1960s, was introduced into nursing education as a distinct research methodology in the 1970s. The theory is grounded in a critique of the dominant contemporary approach to social inquiry, which imposed "enduring" theoretical propositions onto study data. Rather than starting from a set theoretical framework, grounded theory relies on researchers distinguishing meaningful constructs from generated data and then identifying an appropriate theory. Grounded theory is thus particularly useful in investigating complex issues and behaviours not previously addressed and concepts and relationships in particular populations or places that are still undeveloped or weakly connected. Grounded theory data analysis processes include open, axial and selective coding levels. The purpose of this article was to explore the grounded theory research process and provide an initial understanding of this methodology.

  5. The Complexity of Background Clutter Affects Nectar Bat Use of Flower Odor and Shape Cues.

    Directory of Open Access Journals (Sweden)

    Nathan Muchhala

    Full Text Available Given their small size and high metabolism, nectar bats need to be able to quickly locate flowers during foraging bouts. Chiropterophilous plants depend on these bats for their reproduction, thus they also benefit if their flowers can be easily located, and we would expect that floral traits such as odor and shape have evolved to maximize detection by bats. However, relatively little is known about the importance of different floral cues during foraging bouts. In the present study, we undertook a set of flight cage experiments with two species of nectar bats (Anoura caudifer and A. geoffroyi and artificial flowers to compare the importance of shape and scent cues in locating flowers. In a training phase, a bat was presented an artificial flower with a given shape and scent, whose position was constantly shifted to prevent reliance on spatial memory. In the experimental phase, two flowers were presented, one with the training-flower scent and one with the training-flower shape. For each experimental repetition, we recorded which flower was located first, and then shifted flower positions. Additionally, experiments were repeated in a simple environment, without background clutter, or a complex environment, with a background of leaves and branches. Results demonstrate that bats visit either flower indiscriminately with simple backgrounds, with no significant difference in terms of whether they visit the training-flower odor or training-flower shape first. However, in a complex background olfaction was the most important cue; scented flowers were consistently located first. This suggests that for well-exposed flowers, without obstruction from clutter, vision and/or echolocation are sufficient in locating them. In more complex backgrounds, nectar bats depend more heavily on olfaction during foraging bouts.

  6. Path Planning for Non-Circular, Non-Holonomic Robots in Highly Cluttered Environments.

    Science.gov (United States)

    Samaniego, Ricardo; Lopez, Joaquin; Vazquez, Fernando

    2017-08-15

    This paper presents an algorithm for finding a solution to the problem of planning a feasible path for a slender autonomous mobile robot in a large and cluttered environment. The presented approach is based on performing a graph search on a kinodynamic-feasible lattice state space of high resolution; however, the technique is applicable to many search algorithms. With the purpose of allowing the algorithm to consider paths that take the robot through narrow passes and close to obstacles, high resolutions are used for the lattice space and the control set. This introduces new challenges because one of the most computationally expensive parts of path search based planning algorithms is calculating the cost of each one of the actions or steps that could potentially be part of the trajectory. The reason for this is that the evaluation of each one of these actions involves convolving the robot's footprint with a portion of a local map to evaluate the possibility of a collision, an operation that grows exponentially as the resolution is increased. The novel approach presented here reduces the need for these convolutions by using a set of offline precomputed maps that are updated, by means of a partial convolution, as new information arrives from sensors or other sources. Not only does this improve run-time performance, but it also provides support for dynamic search in changing environments. A set of alternative fast convolution methods are also proposed, depending on whether the environment is cluttered with obstacles or not. Finally, we provide both theoretical and experimental results from different experiments and applications.

  7. Application of time-reversal-based processing techniques to enhance detection of GPR targets

    CERN Document Server

    Santos, Vinicius R N

    2016-01-01

    In this paper we analyze the performance of time-reversal (TR) techniques in conjunction with various Ground Penetrating Radar (GPR) pre-processing methods aimed at improving detection of subsurface targets. TR techniques were first developed for ultrasound applications and, by exploiting the invariance of the wave equation under time reversal, can yield features such as superresolution and statistical stability. The TR method was examined here using both synthetic and actual GPR field data under four different pre-processing strategies on the raw data, namely: mean background removal, eigenvalue background removal, a sliding-window space-frequency technique, and a noise-robust spatial differentiator along the scan direction. Depending on the acquisition mode, it was possible to determine with good precision the position and depth of the studied targets as well as, in some cases, to differentiate the targets from nearby clutter such as localized geological anomalies. The proposed methodology has the potential...

  8. Analysis of the ground vibration produced by debris flows and other torrential processes at the Rebaixader monitoring site (Central Pyrenees, Spain

    Directory of Open Access Journals (Sweden)

    C. Abancó

    2013-08-01

    Full Text Available The use of ground vibration sensors for debris-flow monitoring has increased in the last two decades. However, the correct interpretation of the seismic signals produced by debris flows still presents many uncertainties. In the Rebaixader monitoring site (Central Pyrenees, Spain two different ground vibration stations with different characteristics in terms of recording systems and site-specific factors have been compared. The shape of the time series has been recognised as one of the key parameters to identify events and to distinguish between different types of torrential processes. The results show that the site-specific factors strongly influence on the ground vibration registered at each geophone. The attenuation of the signal with the distance has been identified as linear to exponential. In addition, the assembly of the geophones to the terrain also has an important effect on the amplification of the signal. All these results highlight that the definition of ground vibration thresholds for debris-flow detection or warning purposes is a difficult task which is clearly influenced by site-specific conditions of the geophones.

  9. Ground-based simulation of telepresence for materials science experiments. [remote viewing and control of processes aboard Space Station

    Science.gov (United States)

    Johnston, James C.; Rosenthal, Bruce N.; Bonner, Mary JO; Hahn, Richard C.; Herbach, Bruce

    1989-01-01

    A series of ground-based telepresence experiments have been performed to determine the minimum video frame rate and resolution required for the successive performance of materials science experiments in space. The approach used is to simulate transmission between earth and space station with transmission between laboratories on earth. The experiments include isothermal dendrite growth, physical vapor transport, and glass melting. Modifications of existing apparatus, software developed, and the establishment of an inhouse network are reviewed.

  10. Ground-based simulation of telepresence for materials science experiments. [remote viewing and control of processes aboard Space Station

    Science.gov (United States)

    Johnston, James C.; Rosenthal, Bruce N.; Bonner, Mary JO; Hahn, Richard C.; Herbach, Bruce

    1989-01-01

    A series of ground-based telepresence experiments have been performed to determine the minimum video frame rate and resolution required for the successive performance of materials science experiments in space. The approach used is to simulate transmission between earth and space station with transmission between laboratories on earth. The experiments include isothermal dendrite growth, physical vapor transport, and glass melting. Modifications of existing apparatus, software developed, and the establishment of an inhouse network are reviewed.

  11. Detachment of Tertiary Dendrite Arms during Controlled Directional Solidification in Aluminum - 7 wt Percent Silicon Alloys: Observations from Ground-based and Microgravity Processed Samples

    Science.gov (United States)

    Grugel, Richard N.; Erdman, Robert; Van Hoose, James R.; Tewari, Surendra; Poirier, David

    2012-01-01

    Electron Back Scattered Diffraction results from cross-sections of directionally solidified aluminum 7wt% silicon alloys unexpectedly revealed tertiary dendrite arms that were detached and mis-oriented from their parent arm. More surprisingly, the same phenomenon was observed in a sample similarly processed in the quiescent microgravity environment aboard the International Space Station (ISS) in support of the joint US-European MICAST investigation. The work presented here includes a brief introduction to MICAST and the directional solidification facilities, and their capabilities, available aboard the ISS. Results from the ground-based and microgravity processed samples are compared and possible mechanisms for the observed tertiary arm detachment are suggested.

  12. Clutter modeling and suppression for airborne fire control radar with conformal antennas array%共形阵机载火控雷达杂波建模与杂波抑制

    Institute of Scientific and Technical Information of China (English)

    段克清; 谢文冲; 王永良; 张增辉

    2011-01-01

    Airborne fire control radar with conformal antennas array offers many advantages over conventional one with planar antenna array, such as less payload weight, larger effective aperture and increased field of view, without mechanically canting or rotating the array. The airborne fire control radar with conformal antennas array is analyzed in terms of subarray division, clutter characteristics and clutter suppression, etc. Firstly, the mathematical model and geometry configuration of conformal antennas array are given, and the manners of subarray division and working are obtained based on the requirement for the moved target detection of airborne fire control radar, and the properties of conformal antennas array pattern are analyzed. Secondly, the clutter spectrum distribution in space-time plane is analyzed. Finally, the clutter suppression performance of existing space time adaptive processing (STAP) techniques for practice is compared, and the minimum detectable velocity of airborne fire control radar with conformal antennas array is shown.%共形阵机载火控雷达较常规平面阵机载火控雷达有着更少的负载、更好的空气动力性能及更大的扫描范围等优点.对机头共形阵火控雷达的子阵划分、方向图特性、杂波建模和杂波抑制等问题进行了研究.首先,给出了机头共形阵天线的数学模型和几何结构,依据火控雷达动目标检测需求确定了该天线工作方式和子阵合成方式,并分析了机头共形阵的天线方向图特性;然后,结合共形阵阵面结构特点分析了机头共形阵的杂波谱分布特性;最后,利用空时自适应处理(space time adaptive processing,STAP)方法对共形阵机载火控雷达进行了杂波抑制处理,并通过仿真分析了STAP方法的杂波抑制性能.

  13. Grounded theory.

    Science.gov (United States)

    Harris, Tina

    2015-04-29

    Grounded theory is a popular research approach in health care and the social sciences. This article provides a description of grounded theory methodology and its key components, using examples from published studies to demonstrate practical application. It aims to demystify grounded theory for novice nurse researchers, by explaining what it is, when to use it, why they would want to use it and how to use it. It should enable nurse researchers to decide if grounded theory is an appropriate approach for their research, and to determine the quality of any grounded theory research they read.

  14. Implementation of a ground truth process for development of a submerged aquatic vegetation (SAV) mapping protocol using hyperspectral imagery

    Science.gov (United States)

    Hall, Carlton R.; Bostater, Charles R., Jr.; Virnstein, Robert W.

    2006-09-01

    Protocol development for science based mapping of submerged aquatic vegetation (SAV) requires comprehensive ground truth data describing the full range of variability observed in the target. The Indian River Lagoon, Florida, extends along 250 km of the east central Florida coast adjacent to the Atlantic Ocean. The lagoon crosses the transition zone between the Caribbean and Carolinian zoogeographic provinces making it highly diverse. For large scale mapping and management of SAV four common and three uncommon species of seagrass (Tracheophyta) and three broad groups of macroalgae; red algae (Rhodophyta), green algae (Chlorophyta), and brown algae (Phaeophyta) are recognized. Based on technical and cost limitations we established twenty, 7-10 km long flight transects for collection of 1.2 m2 spatial resolution hyperspectral imagery covering the length of the lagoon. Emphasis was placed on the area near the Sebastian River and adjacent Sebastian Inlet. Twenty six 40 m long ground truth transects were established in the lagoon using 1 m2 white panels to mark each transect end. Each transect target was located in the field using high precision GPS. Transects were positioned to cover a range of depths, SAV densities, mixed and monotypic species beds, water quality conditions and general sediment types. A 3 m wide by 30 m long grid was centered on each transect to avoid spectral influences of the white targets. Water depth, species of seagrasses, estimates of vegetation cover percentage, estimates of epiphytic density, and measured canopy height were made for each 1 m2 (n=90). This target based grid arrangement allows for identification and extraction of pixel based hyperspectral signatures corresponding to individual ground truth grid cells without significant concern for rectification and registration error.

  15. How much is particulate matter near the ground influenced by upper level processes within and above the PBL? A summertime case study in Milan (Italy

    Directory of Open Access Journals (Sweden)

    G. Curci

    2014-10-01

    Full Text Available Chemical and dynamical processes yield to the formation of aerosol layers in the upper planetary boundary layer (PBL and above it. Through vertical mixing and entrainment into the PBL these layers may contribute to the ground-level particulate matter (PM, but a quantitative assessment of such contribution is still missing. This study investigates this aspect combining chemical and physical aerosol measurements with WRF/Chem model simulations. The observations were collected in the Milan urban area (Northern Italy during summer of 2007. The period coincided with the passage of a meteorological perturbation that cleansed the lower atmosphere, followed by a high pressure period that favoured pollutant accumulation. Lidar observations reveal the formation of elevated aerosol layers and show evidences of their entrainment into the PBL. We analyze the budget of ground-level PM2.5 (particulate matter with aerodynamic diameter less than 2.5 μm with the help of the online meteorology-chemistry WRF/Chem model, with particular focus on the contribution of upper level processes. We find that an important player in determining the upper PBL aerosol layer is particulate nitrate, which may reach higher values in the upper PBL (up to 30% of the aerosol mass than the lower. The nitrate formation process is predicted to be largely driven by the relative humidity vertical profile, that may trigger efficient aqueous nitrate formation when exceeding the ammonium nitrate deliquescence point. Secondary PM2.5 produced in the upper half of the PBL may contribute up to 7–8 μg m−3 (or 25% to ground level concentrations on hourly basis. A large potential role is also found to be played by the residual aerosol layer above the PBL, which may occasionally contribute up to 10–12 μg m−3 (or 40% to hourly ground level PM2.5 concentrations during the morning. This study highlights the importance of considering the interplay between chemical and dynamical processes

  16. Rupture process of the main shock of the 2016 Kumamoto earthquake with special reference to damaging ground motions: waveform inversion with empirical Green's functions

    Science.gov (United States)

    Nozu, Atsushi; Nagasaka, Yosuke

    2017-01-01

    In this study, the rupture process of the main shock of the Kumamoto earthquake, particularly the generation of strong ground motions in the frequency range relevant to structural damage, was investigated based on the inversion of strong ground motions. Strong-motion records in the near-source region were mainly utilized because the authors were interested in the generation mechanism of damaging ground motions in the near-source region. Empirical Green's functions (EGFs) were applied to avoid uncertainty in the subsurface structure model. Four cases of inversions with different combinations of small events were used to investigate the dependence of the inversion results on the selection of the small events. It was found that the dependence of the final slip distribution and peak slip velocity distribution on the selection of the EGF events is small. The results clearly indicate that a region of significantly large slip and slip velocity existed approximately 15 km northeast of the hypocenter. However, no "asperity" was observed between the hypocenter and Mashiki. Thus, it is not appropriate to conclude that the large-amplitude pulse-like ground motion in Mashiki was generated by the forward-directivity effect associated with the rupture of an asperity. As far as the source effect is concerned, the ground motion in Mashiki cannot be interpreted as the worst case scenario. On the other hand, the rupture of the "asperity" 15 km northeast of the hypocenter should have caused significantly large ground motions in regions close to the asperity. The significant damage of highway bridges in the region can potentially be attributed to the rupture of the asperity. The result of this study was compared with an inversion result obtained from numerical Green's functions for a layered half-space. The two results share the main features in spite of the difference of the Green's functions and stations used. Therefore, it can be concluded that these two source models capture the

  17. Geochemical processes in ground water resulting from surface mining of coal at the Big Sky and West Decker Mine areas, southeastern Montana

    Science.gov (United States)

    Clark, D.W.

    1995-01-01

    A potential hydrologic effect of surface mining of coal in southeastern Montana is a change in the quality of ground water. Dissolved-solids concen- trations in water in spoils aquifers generally are larger than concentrations in water in the coal aquifers they replaced; however, laboratory experiments have indicated that concentrations can decrease if ground water flows from coal-mine spoils to coal. This study was conducted to determine if decreases in concentrations occur onsite and, if so, which geochemical processes caused the decreases. Solid-phase core samples of spoils, unmined over- burden, and coal, and ground-water samples were collected from 16 observation wells at two mine areas. In the Big Sky Mine area, changes in ground- water chemistry along a flow path from an upgradient coal aquifer to a spoils aquifer probably were a result of dedolomitization. Dissolved-solids concentrations were unchanged as water flowed from a spoils aquifer to a downgradient coal aquifer. In the West Decker Mine area, dissolved-solids concentrations apparently decreased from about 4,100 to 2,100 milligrams per liter as water moved along an inferred flow path from a spoils aquifer to a downgradient coal aquifer. Geochemical models were used to analyze changes in water chemistry on the basis of results of solid-phase and aqueous geochemical characteristics. Geochemical processes postulated to result in the apparent decrease in dissolved-solids concentrations along this inferred flow path include bacterial reduction of sulfate, reverse cation exchange within the coal, and precipitation of carbonate and iron-sulfide minerals.

  18. Status of the Correlation Process of the V-HAB Simulation with Ground Tests and ISS Telemetry Data

    Science.gov (United States)

    Ploetner, Peter; Anderson, Molly S.; Czupalla, Markus; Ewert, Micahel K.; Roth, Christof Martin; Zhulov, Anton

    2012-01-01

    The Virtual Habitat (V-HAB) is a dynamic Life Support System (LSS) simulation, created to investigate future human spaceflight missions. V-HAB provides the capability to optimize LSS during early design phases. Furthermore, it allows simulation of worst case scenarios which cannot be tested in reality. In a nutshell, the tool allows the testing of LSS robustness by means of computer simulations. V-HAB is a modular simulation consisting of a: 1. Closed Environment Module 2. Crew Module 3. Biological Module 4. Physio-Chemical Module The focus of the paper will be the correlation and validation of V-HAB against ground test and flight data. The ECLSS technologies (CDRA, CCAA, OGA, etc.) are correlated one by one against available ground test data, which is briefly described in this paper. The technology models in V-HAB are merged to simulate the ISS ECLSS. This simulation is correlated against telemetry data from the ISS, including the water recovery system and the air revitalization system. Finally, an analysis of the results is included in this paper.

  19. MODFLOW-2000, the U.S. Geological Survey Modular Ground-Water Model--Documentation of the SEAWAT-2000 Version with the Variable-Density Flow Process (VDF) and the Integrated MT3DMS Transport Process (IMT)

    Science.gov (United States)

    Langevin, Christian D.; Shoemaker, W. Barclay; Guo, Weixing

    2003-01-01

    SEAWAT-2000 is the latest release of the SEAWAT computer program for simulation of three-dimensional, variable-density, transient ground-water flow in porous media. SEAWAT-2000 was designed by combining a modified version of MODFLOW-2000 and MT3DMS into a single computer program. The code was developed using the MODFLOW-2000 concept of a process, which is defined as ?part of the code that solves a fundamental equation by a specified numerical method.? SEAWAT-2000 contains all of the processes distributed with MODFLOW-2000 and also includes the Variable-Density Flow Process (as an alternative to the constant-density Ground-Water Flow Process) and the Integrated MT3DMS Transport Process. Processes may be active or inactive, depending on simulation objectives; however, not all processes are compatible. For example, the Sensitivity and Parameter Estimation Processes are not compatible with the Variable-Density Flow and Integrated MT3DMS Transport Processes. The SEAWAT-2000 computer code was tested with the common variable-density benchmark problems and also with problems representing evaporation from a salt lake and rotation of immiscible fluids.

  20. Heritability and Genetic Relationship of Adult Self-Reported Stuttering, Cluttering and Childhood Speech-Language Disorders

    DEFF Research Database (Denmark)

    Fagnani, Corrado; Fibiger, Steen; Skytthe, Axel

    2011-01-01

    Genetic influence and mutual genetic relationship for adult self-reported childhood speech-language disorders, stuttering, and cluttering were studied. Using nationwide questionnaire answers from 34,944 adult Danish twins, a multivariate biometric analysis based on the liability-threshold model...... for monozygotic compared to dizygotic pairs, suggesting genetic influence. Multivariate biometric analyses showed that additive genetic and unique environmental factors best explained the observed concordance patterns. Heritability estimates for males/females were 0.71/0.87 for childhood speech-language disorders......, 0.78/0.80 for stuttering, and 0.53/0.65 for cluttering. For each trait, the same genes were suggested to affect liability in males and females. Furthermore, high genetic correlations between the traits were obtained; the estimates for childhood speech-language disorders and stuttering were 0...

  1. Ground-based verification and data processing of Yutu rover Active Particle-induced X-ray Spectrometer

    CERN Document Server

    Guo, Dongya; Peng, Wenxi; Cui, Xingzhu; Zhang, Chengmo; Liu, Yaqing; Liang, Xiaohua; Dong, Yifan; Wang, Jinzhou; Gao, Min; Yang, Jiawei; Zhang, Jiayu; Li, Chunlai; Zou, Yongliao; Zhang, Guangliang; Zhang, Liyan; Fu, Xiaohui

    2015-01-01

    The Active Particle-induced X-ray Spectrometer (APXS) is one of the payloads on board the Yutu rover of Chang'E-3 mission. In order to assess the instrumental performance of APXS, a ground verification test was done for two unknown samples (basaltic rock, mixed powder sample). In this paper, the details of the experiment configurations and data analysis method are presented. The results show that the elemental abundance of major elements can be well determined by the APXS with relative deviations < 15 wt. % (detection distance = 30 mm, acquisition time = 30 min). The derived detection limit of each major element is inversely proportional to acquisition time and directly proportional to detection distance, suggesting that the appropriate distance should be < 50mm.

  2. Data Processing for the Near Earth Asteroid Rendezvous (NEAR), X-Ray and Gamma-Ray Spectrometer (XRS) Ground System

    Science.gov (United States)

    McClanahan, Timothy P.; Mikheeva, I.; Trombka, J. I.; Floyd, S. R.; Boynton, W. V.; Bailey, H.; Bhangoo, J.; Starr, R.; Clark, P. E.; Evans, L. G.

    1999-01-01

    An X-ray and Gamma-ray spectrometer (XGRS) is onboard the Near Earth Asteroid Rendezvous (NEAR) spacecraft to determine the elemental composition of the surface of the asteroid 433Eros. The Eros asteroid is highly non-spherical in physical shape and the development of data management and analysis methodologies are in several areas a divergence from traditional remotely sensed geographical information systems techniques. Field of view and asteroid surface geometry must be derived virtually and then combined with real measurements of solar, spectral and instrument calibration information to derive meaningful scientific results. Spatial resolution of planned geochemical maps will be improved from the initial conditions of low statistical significance per integration by repeated surface flyovers and regional spectral accumulation. This paper describes the results of a collaborative effort of design and development of the NEAR XGRS instrument ground system undertaken by participants at the Goddard Space Flight Center, University of Arizona, Cornell University, Applied Physics Laboratory, and Max Plank institute.

  3. Data Processing for the Near Earth Asteroid Rendezvous (NEAR), X-ray and Gamma-ray Spectrometer (XGRS) Ground System

    Science.gov (United States)

    McClanahan, Timothy P.; Mikheeva, I.; Trombka, J. I.; Floyd, S. R.; Boynton, W. V.; Bailey, H.; Bhangoo, J.; Starr, R.; Clark, P. E.; Evans, L. G.

    1999-01-01

    An X-ray and Gamma-ray spectrometer (XGRS) is onboard the Near Earth Asteroid Rendezvous (NEAR) spacecraft to determine the elemental composition of the surface of the asteroid 433Eros. The Eros asteroid is highly non-spherical in physical shape and the development of data management and analysis methodologies are in several areas a divergence from traditional remotely sensed geographical information systems techniques. Field of view and asteroid surface geometry must be derived virtually and then combined with real measurements of solar, spectral and instrument calibration information to derive meaningful scientific results. Spatial resolution of planned geochemical maps will be improved from the initial conditions of low statistical significance per integration by repeated surface flyovers and regional spectral accumulation. This paper describes the results of a collaborative effort of design and development of the NEAR XGRS instrument ground system undertaken by participants at the Goddard Space Flight Center, University of Arizona, Cornell University, Applied Physics Laboratory, and Max Plank institute.

  4. Ground-based verification and data processing of Yutu rover Active Particle-induced X-ray Spectrometer

    Institute of Scientific and Technical Information of China (English)

    GUO Dong-Ya; WANG Huan-Yu; PENG Wen-Xi; CUI Xing-Zhu; ZHANG Cheng-Mo; LIU Ya-Qing; LIANG Xiao-Hua

    2015-01-01

    The Active Particle-induced X-ray Spectrometer (APXS) is one of the payloads on board the Yutu rover of the Chang'E-3 mission.In order to assess the instrumental performance of APXS,a ground verification test was performed for two unknown samples (basaltic rock,mixed powder sample).In this paper,the details of the experiment configurations and data analysis method are presented.The results show that the elemental abundance of major elements can be well determined by the APXS with relative deviations <15 wt.% (detection distance=30 mm,acquisition time=30 min).The derived detection limit of each major element is inversely proportional to acquisition time and directly proportional to detection distance,suggesting that the appropriate distance should be <50 mm.

  5. From the clouds to the ground - snow precipitation patterns vs. snow accumulation patterns

    Science.gov (United States)

    Gerber, Franziska; Besic, Nikola; Mott, Rebecca; Gabella, Marco; Germann, Urs; Bühler, Yves; Marty, Mauro; Berne, Alexis; Lehning, Michael

    2017-04-01

    patterns show a snowfall gradient consistent with the prevailing wind direction. Deriving snow accumulation based on radar data is challenging as the close-ground precipitation patters cannot be resolved by the radar due to shielding and ground clutter in highly complex terrain. Nonetheless, radar measurements show distinct patterns of snowfall and accumulation, which may be the result of orographic enhancement. Station-based snow accumulation measurements are in reasonable agreement with the estimated large-scale radar snow accumulation. The ADS-based snow accumulation maps feature much smaller scale snow accumulation patterns likely due to close-ground wind effects and snow redistribution on top of an altitudinal gradient. To evaluate microphysical processes and patterns influenced by the topography we run a hydrometeor classification on the radar data. The relative importance of topographically induced effects on snow accumulation patterns is investigated based on vertical cross sections of hydrometeor data and corresponding snow accumulation.

  6. GPR Signal Processing with Geography Adaptive Scanning using Vector Radar for Antipersonal Landmine Detection

    OpenAIRE

    Shinsuke Sato; Zakarya Zyada; Takayuki Matsuno; Yasuhiro Kawai; Yasuhisa Hasegawa; Toshio Fukuda

    2007-01-01

    Ground Penetrating Radar (GPR) is a promising sensor for landmine detection, however there are two major problems to overcome. One is the rough ground surface. The other problem is the distance between the antennas of GPR. It remains irremovable clutters on a sub-surface image output from GPR by first problem. Geography adaptive scanning is useful to image objects beneath rough ground surface. Second problem makes larger the nonlinearity of the relationship between the time for propagation an...

  7. Grounded cognition.

    Science.gov (United States)

    Barsalou, Lawrence W

    2008-01-01

    Grounded cognition rejects traditional views that cognition is computation on amodal symbols in a modular system, independent of the brain's modal systems for perception, action, and introspection. Instead, grounded cognition proposes that modal simulations, bodily states, and situated action underlie cognition. Accumulating behavioral and neural evidence supporting this view is reviewed from research on perception, memory, knowledge, language, thought, social cognition, and development. Theories of grounded cognition are also reviewed, as are origins of the area and common misperceptions of it. Theoretical, empirical, and methodological issues are raised whose future treatment is likely to affect the growth and impact of grounded cognition.

  8. Water erosion as a cause for agricultural soil loss: modeling of dynamic processes using high-resolution ground based LiDAR measurements

    Science.gov (United States)

    Oz, Imri; Filin, Sagi; Assouline, Shmuel; Shtain, Zachi; Furman, Alexander

    2016-04-01

    Soil erosion by rainfall and water flow is a frequent natural geomorphic process shaping the earth's surface at various scales. Conventional agrotechnical methods enhance soil erosion at the field scale and are at the origin of the reduction of the upper soil layer depth. This reduction is expressed in two aspects: decrease of soil depth, mainly due to erosion, and the diminution of soil quality, mainly due to the loss of fine material, nutrients and organic matter. Rain events, not even the most extremes, cause detachment and transport of fertile soil rich in organic matter and nutrients away from the fields, filling and plugging drainage channels, blocking infrastructure and contaminating water sources. Empirical, semi-empirical and mechanistic models are available to estimate soil erosion by water flow and sediment transport (e.g. WEPP, KINEROSS, EUROSEM). Calibration of these models requires data measured at high spatial and temporal resolutions. Development of high-resolution measurement tools (for both spatial and temporal aspects) should improve the calibration of functions related to particles detachment and transport from the soil surface. In addition, despite the great impact of different tillage systems on the soil erosion process, the vast majority of the models ignore this fundamental factor. The objective of this study is to apply high-resolution ground-based LiDAR measurements to different tillage schemes and scales to improve the ability of models to accurately describe the process of soil erosion induced by rainfall and overland flow. Ground-based laser scans provide high resolution accurate and subtle geomorphic changes, as well as larger-scale deformations. As such, it allows frequent monitoring, so that even the effect of a single storm can be measured, thus improving the calibration of the erosion models. Preliminary results for scans made in the field show the potential and limitations of ground-based LiDAR, and at this point qualitatively can

  9. Physically-based modifications to the Sacramento Soil Moisture Accounting model. Part A: Modeling the effects of frozen ground on the runoff generation process

    Science.gov (United States)

    Koren, Victor; Smith, Michael; Cui, Zhengtao

    2014-11-01

    This paper presents the first of two physically-based modifications to a widely-used and well-validated hydrologic precipitation-runoff model. Here, we modify the Sacramento Soil Moisture Accounting (SAC-SMA) model to include a physically-based representation of the effects of freezing and thawing soil on the runoff generation process. This model is called the SAC-SMA Heat Transfer model (SAC-HT). The frozen ground physics are taken from the Noah land surface model which serves as the land surface component of several National Center for Environmental Prediction (NCEP) numerical weather prediction models. SAC-HT requires a boundary condition of the soil temperature at the bottom of the soil column (a climatic annual air temperature is typically used, and parameters derived from readily available soil texture data). A noteworthy feature of SAC-HT is that the frozen ground component needs no parameter calibration. SAC-HT was tested at 11 sites in the U.S. for soil temperature, one site in Russia for soil temperature and soil moisture, eight basins in the upper Midwest for the effects of frozen-ground on streamflow, and one location for frost depth. High correlation coefficients for simulated soil temperature at three depths at 11 stations were achieved. Multi-year simulations of soil moisture and soil temperature agreed very well at the Valdai, Russia test location. In eight basins affected by seasonally frozen soil in the upper Midwest, SAC-HT provided improved streamflow simulations compared to SAC-SMA when both models used a priori parameters. Further improvement was gained through calibration of the non-frozen ground a priori parameters. Frost depth computed by SAC-HT compared well with observed values in the Root River basin in Minnesota.

  10. Polarization differences in airborne ground penetrating radar performance for landmine detection

    Science.gov (United States)

    Dogaru, Traian; Le, Calvin

    2016-05-01

    The U.S. Army Research Laboratory (ARL) has investigated the ultra-wideband (UWB) radar technology for detection of landmines, improvised explosive devices and unexploded ordnance, for over two decades. This paper presents a phenomenological study of the radar signature of buried landmines in realistic environments and the performance of airborne synthetic aperture radar (SAR) in detecting these targets as a function of multiple parameters: polarization, depression angle, soil type and burial depth. The investigation is based on advanced computer models developed at ARL. The analysis includes both the signature of the targets of interest and the clutter produced by rough surface ground. Based on our numerical simulations, we conclude that low depression angles and H-H polarization offer the highest target-to-clutter ratio in the SAR images and therefore the best radar performance of all the scenarios investigated.

  11. Studies of the dayside boundary layer processes based on ground observations in the svalbard area. Phase 1. Final report, 15 September 1992-14 November 1993

    Energy Technology Data Exchange (ETDEWEB)

    Egeland, A.; Holtet, J.A.; Sandholt, P.E.

    1994-01-13

    Based on extensive, diagnostic ground observations in the Svalbard area (mainly at Ny Alesund at 76 deg A) together with simultaneous, coordinated measurements from east Greenland the EISCAT radars as well as DMSP satellite-recordings, structures and dynamics of the dayside cleft and polar cap region have been obtained. This is an important prerequisite to the understanding of the physics of dayside boundary layers processes. Several papers have been published, many lectures given and a NATO Advanced Workshop related to this program arranged. Possible generation mechanisms of dayside cusp/cleft auroras including magnetic merging, external pressure pulses, Kelvin-Helmholtz-instabilities, and dynamo processes by intruding plasma elements are discussed. Characteristics of these boundary layer processes and their ionospheric effects are a major objective of these studies. The Fast Explorer project as well as the new EISCAT radar.

  12. The potential surface in the ground electronic state of HCP with the isomerization process: the validity of calculating potential surface with DFT methods

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The density functional theory (DFT) provides us an effective way to calculate large cluster systems with moderate computational demands. We calculate potential energy surfaces (PES) with several different approaches of DFT. The PES in the ground electronic state are related to HCP's isomerization process. The calculated PES are compared with the “experimental” PES obtained by fitting from the experimental vibrational spectra and that given by the “accurate” quantum chemistry calculation with more expensive computations. The comparisons show that the potential surfaces calculated with DFT methods can reach the accuracy of less than 0.1 eV.

  13. Expertise Effects in Face-Selective Areas are Robust to Clutter and Diverted Attention, but not to Competition.

    Science.gov (United States)

    McGugin, Rankin Williams; Van Gulick, Ana E; Tamber-Rosenau, Benjamin J; Ross, David A; Gauthier, Isabel

    2015-09-01

    Expertise effects for nonface objects in face-selective brain areas may reflect stable aspects of neuronal selectivity that determine how observers perceive objects. However, bottom-up (e.g., clutter from irrelevant objects) and top-down manipulations (e.g., attentional selection) can influence activity, affecting the link between category selectivity and individual performance. We test the prediction that individual differences expressed as neural expertise effects for cars in face-selective areas are sufficiently stable to survive clutter and manipulations of attention. Additionally, behavioral work and work using event related potentials suggest that expertise effects may not survive competition; we investigate this using functional magnetic resonance imaging. Subjects varying in expertise with cars made 1-back decisions about cars, faces, and objects in displays containing one or 2 objects, with only one category attended. Univariate analyses suggest car expertise effects are robust to clutter, dampened by reducing attention to cars, but nonetheless more robust to manipulations of attention than competition. While univariate expertise effects are severely abolished by competition between cars and faces, multivariate analyses reveal new information related to car expertise. These results demonstrate that signals in face-selective areas predict expertise effects for nonface objects in a variety of conditions, although individual differences may be expressed in different dependent measures depending on task and instructions.

  14. The application of the multifractal cross-correlation analysis methods in radar target detection within sea clutter

    Science.gov (United States)

    Xi, Caiping; Zhang, Shuning; Xiong, Gang; Zhao, Huichang; Yang, Yonghong

    2017-02-01

    Many complex systems generate multifractal time series which are long-range cross-correlated. This paper introduces three multifractal cross-correlation analysis methods, such as multifractal cross-correlation analysis based on the partition function approach (MFXPF), multifractal detrended cross-correlation analysis (MFDCCA) methods based on detrended fluctuation analysis (MFXDFA) and detrended moving average analysis (MFXDMA), which only consider one moment order. We do comparative analysis of the artificial time series (binomial multiplicative cascades and Cantor sets with different probabilities) by these methods. Then we do a feasibility test of the fixed threshold target detection within sea clutter by applying the multifractal cross-correlation analysis methods to the IPIX radar sea clutter data. The results show that it is feasible to use the method of the fixed threshold based on the multifractal feature parameter Δf(α) by the MFXPF and MFXDFA-1 methods. At last, we give the main conclusions and provide a valuable reference on how to choose the multifractal algorithms, the detection parameters and the target detection methods within sea clutter in practice.

  15. Mixture-Tuned, Clutter Matched Filter for Remote Detection of Subpixel Spectral Signals

    Science.gov (United States)

    Thompson, David R.; Mandrake, Lukas; Green, Robert O.

    2013-01-01

    Mapping localized spectral features in large images demands sensitive and robust detection algorithms. Two aspects of large images that can harm matched-filter detection performance are addressed simultaneously. First, multimodal backgrounds may thwart the typical Gaussian model. Second, outlier features can trigger false detections from large projections onto the target vector. Two state-of-the-art approaches are combined that independently address outlier false positives and multimodal backgrounds. The background clustering models multimodal backgrounds, and the mixture tuned matched filter (MT-MF) addresses outliers. Combining the two methods captures significant additional performance benefits. The resulting mixture tuned clutter matched filter (MT-CMF) shows effective performance on simulated and airborne datasets. The classical MNF transform was applied, followed by k-means clustering. Then, each cluster s mean, covariance, and the corresponding eigenvalues were estimated. This yields a cluster-specific matched filter estimate as well as a cluster- specific feasibility score to flag outlier false positives. The technology described is a proof of concept that may be employed in future target detection and mapping applications for remote imaging spectrometers. It is of most direct relevance to JPL proposals for airborne and orbital hyperspectral instruments. Applications include subpixel target detection in hyperspectral scenes for military surveillance. Earth science applications include mineralogical mapping, species discrimination for ecosystem health monitoring, and land use classification.

  16. A Low-Complexity Algorithm for Static Background Estimation from Cluttered Image Sequences in Surveillance Contexts

    Directory of Open Access Journals (Sweden)

    Reddy Vikas

    2011-01-01

    Full Text Available Abstract For the purposes of foreground estimation, the true background model is unavailable in many practical circumstances and needs to be estimated from cluttered image sequences. We propose a sequential technique for static background estimation in such conditions, with low computational and memory requirements. Image sequences are analysed on a block-by-block basis. For each block location a representative set is maintained which contains distinct blocks obtained along its temporal line. The background estimation is carried out in a Markov Random Field framework, where the optimal labelling solution is computed using iterated conditional modes. The clique potentials are computed based on the combined frequency response of the candidate block and its neighbourhood. It is assumed that the most appropriate block results in the smoothest response, indirectly enforcing the spatial continuity of structures within a scene. Experiments on real-life surveillance videos demonstrate that the proposed method obtains considerably better background estimates (both qualitatively and quantitatively than median filtering and the recently proposed "intervals of stable intensity" method. Further experiments on the Wallflower dataset suggest that the combination of the proposed method with a foreground segmentation algorithm results in improved foreground segmentation.

  17. Great expectations: top-down attention modulates the costs of clutter and eccentricity.

    Science.gov (United States)

    Steelman, Kelly S; McCarley, Jason S; Wickens, Christopher D

    2013-12-01

    An experiment and modeling effort examined interactions between bottom-up and top-down attentional control in visual alert detection. Participants performed a manual tracking task while monitoring peripheral display channels for alerts of varying salience, eccentricity, and spatial expectancy. Spatial expectancy modulated the influence of salience and eccentricity; alerts in low-probability locations engendered higher miss rates, longer detection times, and larger costs of visual clutter and eccentricity, indicating that top-down attentional control offset the costs of poor bottom-up stimulus quality. Data were compared to the predictions of a computational model of scanning and noticing that incorporates bottom-up and top-down sources of attentional control. The model accounted well for the overall pattern of miss rates and response times, predicting each of the observed main effects and interactions. Empirical results suggest that designers should expect the costs of poor bottom-up visibility to be greater for low expectancy signals, and that the placement of alerts within a display should be determined based on the combination of alert expectancy and response priority. Model fits suggest that the current model can serve as a useful tool for exploring a design space as a precursor to empirical data collection and for generating hypotheses for future experiments.

  18. Object Extraction in Cluttered Environments via a P300-Based IFCE

    Directory of Open Access Journals (Sweden)

    Xiaoqian Mao

    2017-01-01

    Full Text Available One of the fundamental issues for robot navigation is to extract an object of interest from an image. The biggest challenges for extracting objects of interest are how to use a machine to model the objects in which a human is interested and extract them quickly and reliably under varying illumination conditions. This article develops a novel method for segmenting an object of interest in a cluttered environment by combining a P300-based brain computer interface (BCI and an improved fuzzy color extractor (IFCE. The induced P300 potential identifies the corresponding region of interest and obtains the target of interest for the IFCE. The classification results not only represent the human mind but also deliver the associated seed pixel and fuzzy parameters to extract the specific objects in which the human is interested. Then, the IFCE is used to extract the corresponding objects. The results show that the IFCE delivers better performance than the BP network or the traditional FCE. The use of a P300-based IFCE provides a reliable solution for assisting a computer in identifying an object of interest within images taken under varying illumination intensities.

  19. Stochastic transfer of polarized radiation in finite cluttered atmospheric media with dual statistical analysis

    Science.gov (United States)

    Sallah, M.

    2015-09-01

    The stochastic transfer of polarized radiation in a finite cluttered atmospheric medium (e.g. clouds) is investigated, the solution being presented for arbitrary absorption and scattering cross sections. The extinction function of the medium is assumed to be a continuous random function of position, with fluctuations about the mean taken as Gaussian distributed. The deterministic analytical solution is obtained by using Pomraning-Eddington technique with weight function method. Two correlated random variables appear in the solution, namely the optical space variable and the medium optical thickness. The dual Gaussian probability density function of these two random variables is derived, from which the ensemble-averaged solution is calculated for an arbitrary correlation function. The first and the second statistical moments of some quantities of interest, such as radiant energy, net flux, reflectivity and transmissivity, are obtained. Numerical calculations are performed for specular-reflecting boundaries and an incident flux of radiation upon the medium from one side (x = 0) and with no flux from other side (x = L) .

  20. Reinforcement Learning with Autonomous Small Unmanned Aerial Vehicles in Cluttered Environments

    Science.gov (United States)

    Tran, Loc; Cross, Charles; Montague, Gilbert; Motter, Mark; Neilan, James; Qualls, Garry; Rothhaar, Paul; Trujillo, Anna; Allen, B. Danette

    2015-01-01

    We present ongoing work in the Autonomy Incubator at NASA Langley Research Center (LaRC) exploring the efficacy of a data set aggregation approach to reinforcement learning for small unmanned aerial vehicle (sUAV) flight in dense and cluttered environments with reactive obstacle avoidance. The goal is to learn an autonomous flight model using training experiences from a human piloting a sUAV around static obstacles. The training approach uses video data from a forward-facing camera that records the human pilot's flight. Various computer vision based features are extracted from the video relating to edge and gradient information. The recorded human-controlled inputs are used to train an autonomous control model that correlates the extracted feature vector to a yaw command. As part of the reinforcement learning approach, the autonomous control model is iteratively updated with feedback from a human agent who corrects undesired model output. This data driven approach to autonomous obstacle avoidance is explored for simulated forest environments furthering autonomous flight under the tree canopy research. This enables flight in previously inaccessible environments which are of interest to NASA researchers in Earth and Atmospheric sciences.

  1. Bistatic, above-critical angle scattering measurements of fully buried unexploded ordnance (UXO) and clutter.

    Science.gov (United States)

    Waters, Z J; Simpson, H J; Sarkissian, A; Dey, S; Houston, B H; Bucaro, J A; Yoder, T J

    2012-11-01

    Laboratory grade bistatic scattering measurements are conducted in order to examine the acoustic response of realistic fully buried unexploded ordnance (UXO) from above-critical angle insonification, between 2 and 40 kHz. A 127 mm diameter rocket UXO, a 155 mm diameter artillery shell, a natural rock of approximately the same size, and a cinder block are fully buried in water-saturated medium grained sand (mean grain diameter, 240 μm) at depths of 10 cm below the water-sediment interface. A two-dimensional array of bistatic scattering measurements is generated synthetically by scanning a single hydrophone in steps of 3 cm over a 1 m × 1 m patch directly above the targets at a height of 20 cm above the water-sediment interface. Three-dimensional volumetric acoustic images generated from the return waveforms reveal scattering components attributed to geometric and elastic scattering, as well as multiple-scattering interactions of returns between the sediment-water interface and the buried objects. The far-field target strength of the objects is estimated through extrapolation of the angular spectrum. Agreement is found between experimental data and simulated data generated from a finite-element-based, three-dimensional time-harmonic model (2-25 kHz). Separation of the measured UXO from the clutter objects is demonstrated through exploitation of structural-acoustics-based features.

  2. Significance of spatial variability in precipitation for process-oriented modelling: results from two nested catchments using radar and ground station data

    Directory of Open Access Journals (Sweden)

    D. Tetzlaff

    2005-01-01

    Full Text Available The importance of considering the spatial distribution of rainfall for process-oriented hydrological modelling is well-known. However, the application of rainfall radar data to provide such detailed spatial resolution is still under debate. In this study the process-oriented TACD (Tracer Aided Catchment model, Distributed model had been used to investigate the effects of different spatially distributed rainfall input on simulated discharge and runoff components on an event base. TACD is fully distributed (50x50m2 raster cells and was applied on an hourly base. As model input rainfall data from up to 7 ground stations and high resolution rainfall radar data from operational C-band radar were used. For seven rainfall events the discharge simulations were investigated in further detail for the mountainous Brugga catchment (40km2 and the St. Wilhelmer Talbach (15.2km2 sub-basin, which are located in the Southern Black Forest Mountains, south-west Germany. The significance of spatial variable precipitation data was clearly demonstrated. Dependent on event characteristics, localized rain cells were occasionally poorly captured even by a dense ground station network, and this resulted in inadequate model results. For such events, radar data can provide better input data. However, an extensive data adjustment using ground station data is required. For this purpose a method was developed that considers the temporal variability in rainfall intensity in high temporal resolution in combination with the total rainfall amount of both data sets. The use of the distributed catchment model allowed further insights into spatially variable impacts of different rainfall estimates. Impacts for discharge predictions are the largest in areas that are dominated by the production of fast runoff components. The improvements for distributed runoff simulation using high resolution rainfall radar input data are strongly dependent on the investigated scale, the event

  3. A framework for the natural-language-perception-based creative control of unmanned ground vehicles

    Science.gov (United States)

    Ghaffari, Masoud; Liao, Xiaoqun; Hall, Ernest L.

    2004-09-01

    Mobile robots must often operate in an unstructured environment cluttered with obstacles and with many possible action paths. That is why mobile robotics problems are complex with many unanswered questions. To reach a high degree of autonomous operation, a new level of learning is required. On the one hand, promising learning theories such as the adaptive critic and creative control have been proposed, while on other hand the human brain"s processing ability has amazed and inspired researchers in the area of Unmanned Ground Vehicles but has been difficult to emulate in practice. A new direction in the fuzzy theory tries to develop a theory to deal with the perceptions conveyed by the natural language. This paper tries to combine these two fields and present a framework for autonomous robot navigation. The proposed creative controller like the adaptive critic controller has information stored in a dynamic database (DB), plus a dynamic task control center (TCC) that functions as a command center to decompose tasks into sub-tasks with different dynamic models and multi-criteria functions. The TCC module utilizes computational theory of perceptions to deal with the high levels of task planning. The authors are currently trying to implement the model on a real mobile robot and the preliminary results have been described in this paper.

  4. The Chemi-Ionization Processes in Slow Collisions of Rydberg Atoms with Ground State Atoms: Mechanism and Applications

    CERN Document Server

    Mihajlov, A A; Ignjatovic, Lj M; Klyucharev, A N; 10.1007/s10876-011-0438-7

    2012-01-01

    In this article the history and the current state of research of the chemiionization processes in atom-Rydberg atom collisions is presented. The principal assumptions of the model of such processes based on the dipole resonance mechanism, as well as the problems of stochastic ionization in atom-Rydberg atom collisions, are exposed. The properties of the collision kinetics in atom beams of various types used in contemporary experimentations are briefly described. Results of the calculation of the chemi-ionization rate coefficients are given and discussed for the range of the principal quantum number values 5 < n < 25. The role of the chemi-ionization processes in astrophysical and laboratory low-temperature plasmas, and the contemporary methods of their investigation are described. Also the directions of further research of chemi-ionization processes are discussed in this article.

  5. The Chemi-Ionization Processes in Slow Collisions of Rydberg Atoms with Ground State Atoms: Mechanism and Applications

    OpenAIRE

    Mihajlov, A. A.; Sreckovic, V. A.; Ignjatovic, Lj. M.; Klyucharev, A. N.

    2012-01-01

    In this article the history and the current state of research of the chemiionization processes in atom-Rydberg atom collisions is presented. The principal assumptions of the model of such processes based on the dipole resonance mechanism, as well as the problems of stochastic ionization in atom-Rydberg atom collisions, are exposed. The properties of the collision kinetics in atom beams of various types used in contemporary experimentations are briefly described. Results of the calculation of ...

  6. DESCRIPTION OF THE ORGANIZATIONAL AND TECHNOLOGICAL PROCESSES ON THE GROUND OF THE BASIC MODEL OF THE CYCLE OF REORGANIZATION

    Directory of Open Access Journals (Sweden)

    Gazaryan Robert Kamoevich

    2012-12-01

    Full Text Available The objective of this scientific research is application of the basic model of interaction between phases of a cycle of reorganization of organizational and technological processes underway at industrial enterprises. The authors describe interactions between all six phases of the process of reorganization within the framework of the basic model of a cycle that contemplates organizational and technological processes. Engineering studies are necessary to check for the feasibility of reorganization of industrial enterprises and application of results extracted from the design documentation with a view to reorganization of production activities and construction operations. Upon completion of the decision-making process concerning the need for reorganization in accordance with the basic model of interaction between phases, there occurs restructuring that incorporates processes of design and construction. The authors have demonstrated that reorganization of the basic model cycle should be used in the design of organizational and technological processes with a view to the integrated consideration of reorganization of enterprises in order to comprehend and improve the efficiency of reorganization at each stage, as well as the control over the reorganization of a construction facility.

  7. A presentation of ATR processing chain validation procedure of IR terminal guidance version of the AASM modular air-to-ground weapon

    Science.gov (United States)

    Duclos, D.; Quinquis, N.; Broda, G.; Galmiche, F.; Oudyi, F.; Coulon, N.; Cordier, D.; Sonier, C.

    2009-05-01

    Developed by Sagem (SAFRAN Group), the AASM is a modular Air-To-Ground "Fire and Forget" weapon designed to be able to neutralise a large range of targets under all conditions. The AASM is composed of guidance and range enhancement kits that give bombs, already in service, new operational capabilities. AASM Guidance kit exists in two different versions. The IMU/GPS guidance version is able to achieve "ten-meter class" accuracy on target in all weather conditions. The IMU/GPS/IR guidance version is able to achieve "meter class" accuracy on target with poor precision geographic designation or in GPS-denied flight context, thanks to a IR sensor and a complex image processing chain. In this night/day IMU/GPS/IR version, the terminal guidance phase adjusts the missile navigation to the true target by matching the image viewed through the infrared sensor with a target model stored in the missile memory. This model will already have been drawn up on the ground using a mission planning system and, for example, a satellite image. This paper will present the main steps of the procedure applied to qualify the complete image processing chain of the AASM IMU/GPS/IR version, including open-loop validation of ATR algorithms on real and synthetic images, and closed-loop validation using AASM simulation reference model.

  8. Adapting school-based substance use prevention curriculum through cultural grounding: a review and exemplar of adaptation processes for rural schools.

    Science.gov (United States)

    Colby, Margaret; Hecht, Michael L; Miller-Day, Michelle; Krieger, Janice L; Syvertsen, Amy K; Graham, John W; Pettigrew, Jonathan

    2013-03-01

    A central challenge facing twenty-first century community-based researchers and prevention scientists is curriculum adaptation processes. While early prevention efforts sought to develop effective programs, taking programs to scale implies that they will be adapted, especially as programs are implemented with populations other than those with whom they were developed or tested. The principle of cultural grounding, which argues that health message adaptation should be informed by knowledge of the target population and by cultural insiders, provides a theoretical rational for cultural regrounding and presents an illustrative case of methods used to reground the keepin' it REAL substance use prevention curriculum for a rural adolescent population. We argue that adaptation processes like those presented should be incorporated into the design and dissemination of prevention interventions.

  9. Understanding Students Prior Knowledge On The Process Of Seeing And Perception Of Colors Using The Grounded Theory Implications To Science Teaching

    Directory of Open Access Journals (Sweden)

    Ian Phil Canlas

    2015-08-01

    Full Text Available The foregoing is a part of a developmental study that attempted to investigate the prior knowledge of students on the process of seeing and perception of colors using the Grounded theory approach. One hundred twenty-two 122 university students in their first year taking programs under the College of Education and College of Arts and Sciences enrolled in a course on biological sciences took part in the study. Explanations of the students related to light absorption in photosynthesis were analyzed to establish an illustration on how they understand the process of seeing and perception of colors. Results revealed that a gap in their understanding of these concepts existed despite its introduction during their basic education. The use of common phenomena and daily context as a form of diagnostic assessment and the importance of integrated lessons were also discussed in this paper.

  10. Inactivation of Uropathogenic Escherichia coli in Ground Chicken Meat Using High Pressure Processing and Gamma Radiation, and in Purge and Chicken Meat Surfaces by Ultraviolet Light.

    Science.gov (United States)

    Sommers, Christopher H; Scullen, O J; Sheen, Shiowshuh

    2016-01-01

    Extraintestinal pathogenic Escherichia coli, including uropathogenic E. coli (UPEC), are common contaminants in poultry meat and may cause urinary tract infections after colonization of the gastrointestinal tract and transfer of contaminated feces to the urethra. Three non-thermal processing technologies used to improve the safety and shelf-life of both human and pet foods include high pressure processing (HPP), ionizing (gamma) radiation (GR), and ultraviolet light (UV-C). Multi-isolate cocktails of UPEC were inoculated into ground chicken which was then treated with HPP (4°C, 0-25 min) at 300, 400, or 500 MPa. HPP D10, the processing conditions needed to inactivate 1 log of UPEC, was 30.6, 8.37, and 4.43 min at 300, 400, and 500 MPa, respectively. When the UPEC was inoculated into ground chicken and gamma irradiated (4 and -20°C) the GR D10 were 0.28 and 0.36 kGy, respectively. The UV-C D10 of UPEC in chicken suspended in exudate and placed on stainless steel and plastic food contact surfaces ranged from 11.4 to 12.9 mJ/cm(2). UV-C inactivated ca. 0.6 log of UPEC on chicken breast meat. These results indicate that existing non-thermal processing technologies such as HPP, GR, and UV-C can significantly reduce UPEC levels in poultry meat or exudate and provide safer poultry products for at-risk consumers.

  11. Inactivation of Uropathogenic Escherichia coli in Ground Chicken Meat Using High Pressure Processing and Gamma Radiation, and in Purge and Chicken Meat Surfaces by Ultraviolet Light

    Directory of Open Access Journals (Sweden)

    Christopher H Sommers

    2016-04-01

    Full Text Available Extraintestinal pathogenic Escherichia coli (ExPEC, including uropathogenic E. coli (UPEC are common contaminants in poultry meat and may cause urinary tract infections after colonization of the gastrointestinal tract and transfer of contaminated feces to the urethra. Three nonthermal processing technologies used to improve the safety and shelf-life of both human and pet foods include high pressure processing (HPP, ionizing (gamma radiation (GR, and ultraviolet light (UV-C. Multi-isolate cocktails of UPEC were inoculated into ground chicken which was then treated with HPP (4 oC, 0-25 min at 300, 400 or 500 MPa. HPP D10, the processing conditions needed to inactivate 1 log of UPEC, was 30.6, 8.37, and 4.43 min at 300, 400, and 500 MPa, respectively. When the UPEC was inoculated into ground chicken and gamma irradiated (4 and -20 oC the GR D10 were 0.28 and 0.36 kGy, respectively. The UV-C D10 of UPEC in chicken suspended in exudate and placed on stainless steel and plastic food contact surfaces ranged from 11.4 to 12.9 mJ/cm2. UV-C inactivated ca. 0.6 log of UPEC on chicken breast meat. These results indicate that existing nonthermal processing technologies such as HPP, GR, and UV-C can significantly reduce UPEC levels in poultry meat or exudate and provide safer poultry products for at-risk consumers.

  12. NASA Cold Land Processes Experiment (CLPX 2002/03): Ground-based and near-surface meteorological observations

    Science.gov (United States)

    Kelly Elder; Don Cline; Angus Goodbody; Paul Houser; Glen E. Liston; Larry Mahrt; Nick Rutter

    2009-01-01

    A short-term meteorological database has been developed for the Cold Land Processes Experiment (CLPX). This database includes meteorological observations from stations designed and deployed exclusively for CLPXas well as observations available from other sources located in the small regional study area (SRSA) in north-central Colorado. The measured weather parameters...

  13. The Learning Process of Supervisees Who Engage in the Reflecting Team Model within Group Supervision: A Grounded Theory Inquiry

    Science.gov (United States)

    Pender, Rebecca Lynn

    2012-01-01

    In recent years, counselor educators have begun to incorporate the use of the reflecting team process with the training of counselors. Specifically, the reflecting team has been used in didactic courses (Cox, 2003; Landis & Young, 1994; Harrawood, Wilde & Parmanand, 2011) and in supervision (Cox, 1997; Prest, Darden, & Keller, 1990;…

  14. Methodological Grounds of Formation of the Scorecard of Diagnostics of the Innovation Component of Technological Processes of Industrial Enterprises

    Directory of Open Access Journals (Sweden)

    Zhezhuha Volodymyr Yo.

    2014-01-01

    Full Text Available The goal of the article is development of scientific provisions with respect of methodological specific features of formation of the scorecard of diagnostics of the innovation component of technological processes of industrial enterprises. The article proves fragmentariness of views of theoreticians and practitioners on this problem. It justifies a necessity of formation of these indicators from the point of view of a system approach, consequently, accounting of all interconnections and interdependencies between them, and also coverage of main factors that identify the diagnosed innovation component. Pursuant to result of the study the article specifies system properties of the scorecard of diagnostics of the innovation component of technological processes of industrial enterprises. It reveals a possibility of application of two alternative approaches to formation of this scorecard, and also establishes their advantages and shortcomings. It gives a number of requirements, which have to be met when selecting, developing and forming the scorecard of diagnostics of the innovation component of technological processes of industrial enterprises. It reflects key issues that should form the basis of the methodological approach to formation of this system. It shows typology of indicators of diagnostics of the innovation component of technological processes of industrial enterprises, which gives subjects of diagnostics a possibility to select relevant indicators depending on the set criteria and restrictions. Prospects of further studies in this direction should lie in development of the system of a specific scorecard of diagnostics of each innovation component of technological processes of industrial enterprises with consideration of methodological specific features of its formation described in the article.

  15. Ground Wars

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Kleis

    Political campaigns today are won or lost in the so-called ground war--the strategic deployment of teams of staffers, volunteers, and paid part-timers who work the phones and canvass block by block, house by house, voter by voter. Ground Wars provides an in-depth ethnographic portrait of two...... infrastructures that utilize large databases with detailed individual-level information for targeting voters, and armies of dedicated volunteers and paid part-timers. Nielsen challenges the notion that political communication in America must be tightly scripted, controlled, and conducted by a select coterie...... of professionals. Yet he also quashes the romantic idea that canvassing is a purer form of grassroots politics. In today's political ground wars, Nielsen demonstrates, even the most ordinary-seeming volunteer knocking at your door is backed up by high-tech targeting technologies and party expertise. Ground Wars...

  16. Transport and fate of nitrate in a glacial outwash aquifer in relation to ground water age, land use practices, and redox processes

    Science.gov (United States)

    Puckett, L.J.; Cowdery, T.K.

    2002-01-01

    A combination of ground water modeling, chemical and dissolved gas analyses, and chlorofluorocarbon age dating of water was used to determine the relation between changes in agricultural practices, and NO3- concentrations in ground water of a glacial outwash aquifer in west-central Minnesota. The results revealed a redox zonation throughout the saturated zone with oxygen reduction occurring near the water table, NO3- reduction immediately below it, and then a large zone of ferric iron reduction, with a small area of sulfate (SO42-) reduction and methanogenesis (CH4) near the end of the transect. Analytical and NETPATH modeling results supported the hypothesis that organic carbon served as the electron donor for the redox reactions. Denitrification rates were quite small, 0.005 to 0.047 mmol NO3- yr-1, and were limited by the small amounts of organic carbon, 0.01 to 1.45%. In spite of the organic carbon limitation, denitrification was virtually complete because residence time is sufficient to allow even slow processes to reach completion. Ground water sample ages showed that maximum residence times were on the order of 50 to 70 yr. Reconstructed NO3- concentrations, estimated from measured NO3- and dissolved N gas showed that NO3- concentrations have been increasing in the aquifer since the 1940s, and have been above the 714 ??mol L-1 maximum contaminant level at most sites since the mid- to late-1960s. This increase in NO3- has been accompanied by a corresponding increase in agricultural use of fertilizer, identified as the major source of NO3- to the aquifer.

  17. Advancing Understanding of the Role of Belowground Processes in Terrestrial Carbon Sinks trhrough Ground-Penetrating Radar. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Day, Frank P. [Old Dominion Univ., Norfolk, VA (United States)

    2015-02-06

    Coarse roots play a significant role in belowground carbon cycling and will likely play an increasingly crucial role in belowground carbon sequestration as atmospheric CO2 levels continue to rise, yet they are one of the most difficult ecosystem parameters to quantify. Despite promising results with ground-penetrating radar (GPR) as a nondestructive method of quantifying biomass of coarse roots, this application of GPR is in its infancy and neither the complete potential nor limitations of the technology have been fully evaluated. The primary goals and questions of this study fell into four groups: (1) GPR methods: Can GPR detect change in root biomass over time, differentiate live roots from dead roots, differentiate between coarse roots, fine roots bundled together, and a fine root mat, remain effective with varied soil moisture, and detect shadowed roots (roots hidden below larger roots); (2) CO2 enrichment study at Kennedy Space Center in Brevard County, Florida: Are there post-fire legacy effects of CO2 fertilization on plant carbon pools following the end of CO2application ? (3) Disney Wilderness Study: What is the overall coarse root biomass and potential for belowground carbon storage in a restored longleaf pine flatwoods system? Can GPR effectively quantify coarse roots in soils that are wetter than the previous sites and that have a high percentage of saw palmetto rhizomes present? (4) Can GPR accurately represent root architecture in a three-dimensional model? When the user is familiar with the equipment and software in a setting that minimizes unsuitable conditions, GPR is a relatively precise, non-destructive, useful tool for estimating coarse root biomass. However, there are a number of cautions and guidelines that should be followed to minimize inaccuracies or situations that are untenable for GPR use. GPR appears to be precise as it routinely predicts highly similar values for a given area across multiple

  18. A proposal on the study of solar-terrestrial coupling processes with atmospheric radars and ground-based observation network

    Science.gov (United States)

    Tsuda, Toshitaka; Yamamoto, Mamoru; Hashiguchi, Hiroyuki; Shiokawa, Kazuo; Ogawa, Yasunobu; Nozawa, Satonori; Miyaoka, Hiroshi; Yoshikawa, Akimasa

    2016-09-01

    The solar energy can mainly be divided into two categories: the solar radiation and the solar wind. The former maximizes at the equator, generating various disturbances over a wide height range and causing vertical coupling processes of the atmosphere between the troposphere and middle and upper atmospheres by upward propagating atmospheric waves. The energy and material flows that occur in all height regions of the equatorial atmosphere are named as "Equatorial Fountain." These processes from the bottom also cause various space weather effects, such as satellite communication and Global Navigation Satellite System positioning. While, the electromagnetic energy and high-energy plasma particles in the solar wind converge into the polar region through geomagnetic fields. These energy/particle inflow results in auroral Joule heating and ion drag of the atmosphere particularly during geomagnetic storms and substorms. The ion outflow from the polar ionosphere controls ambient plasma constituents in the magnetosphere and may cause long-term variation of the atmosphere. We propose to clarify these overall coupling processes in the solar-terrestrial system from the bottom and from above through high-resolution observations at key latitudes in the equator and in the polar region. We will establish a large radar with active phased array antenna, called the Equatorial Middle and Upper atmosphere radar, in west Sumatra, Indonesia. We will participate in construction of the EISCAT_3D radar in northern Scandinavia. These radars will enhance the existing international radar network. We will also develop a global observation network of compact radio and optical remote sensing equipment from the equator to polar region.

  19. Channel probe measurements for the American sector clutter experiment, January, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Fitzgerald, T.J.

    1994-05-20

    The ionospheric phenomenon called Equatorial Spread F encompasses a variety of effects associated with plasma irregularities occurring in the post-sunset and nighttime ionosphere near the magnetic equator. These irregularities can seriously degrade the performance of systems which involve either of necessity or inadvertently radio propagation through the equatorial ionosphere. One such system is Over-the-Horizon (OTH) radars which operate in the high-frequency (hf) band and use ionospheric reflection for forward and backscatter propagation to ranges of thousands of kilometers. When such radars are directed towards the equator, Spread F irregularities can cause scintillation effects which may be aliased into the ranges of interest and have the effect of causing, excess clutter in which targets may be hidden. In January, 1994 Los Alamos participated in a campaign to measure Spread F effects on OTH propagation from the United States looking towards South America in conjunction with local diagnostics in Peru. During the campaign Los Alamos fielded a 1600 km bistatic path between Piura, Peru, and Arequipa, Peru-, the one-hop reflection region for this path was near the magnetic equator, We obtained four types of measurements: an oblique ionogram between Piura and Arequipa every three minutes; Doppler spread and spatial correlation for a single frequency cw path between Piura and Arequipa; Doppler spread, time-delay spread, and spatial coherence for a 10 kHz bandwidth path between Piura and Arequipa-, and Doppler spread and time-delay spread for the one-way path between the AVA radar in New York and Arequipa, Peru. This report describes the diagnostic experiments that we carried out and gives a brief description of some of the data we obtained.

  20. Microbially induced carbonate precipitation (MICP) by denitrification as ground improvement method - Process control in sand column experiments

    Science.gov (United States)

    Pham, Vinh; van Paassen, Leon; Nakano, Akiko; Kanayama, Motohei; Heimovaara, Timo

    2013-04-01

    Calcite precipitation induced by microbes has been proven to be efficient in stabilizing granular soils, especially with urea hydrolysis, as it has been successfully demonstrated in a pilot application 2010. However, as a byproduct highly concentrated ammonium chloride (NH4Cl) solution is produced, which has to be removed and disposed and forms a significant disadvantage of the technique that makes an alternative process like denitrification preferred. The proof of principle of microbially induced calcite precipitation (MICP) by denitrification has been demonstrated by Van Paassen et al (2010) who suggested that instead of producing waste as a byproduct, different pre-treated waste streams could be used as substrates for in situ growth of denitrifying bacteria and simultaneous cementation without producing waste to be removed. In this study sand column experiments are performed in which calcium carbonate was successfully precipitated by indigenous denitrifying micro-organisms, which were supplied weekly with a pulse of a substrate solution containing calcium acetate and calcium nitrate. Besides the production of calcite and the growth of bacteria in biofilms, the reduction of nitrate resulted in the production of (nitrogen) gas. It was observed that this gas partly fills up the pore space and consequently contributed to a reduction of the permeability of the treated sand. The presence of gas in the pore space affected the flow of the injected substrates and influenced to the distribution of calcium carbonate. The effect of the mean particle size (D50) on the flow and transport of solutes and gas in the porous media has been evaluated by treating several columns with varying grain size distribution and comparing the change in permeability after each incubation period and analyzing the distribution of the gas throughout the columns using X-ray computed tomography (CT) scanning. The present results show that there is a considerable decrease of permeability - a

  1. Vertical Extraction Process Implemented at the 118-K-1 Burial Ground for Removal of Irradiated Reactor Debris from Silo Structures - 12431

    Energy Technology Data Exchange (ETDEWEB)

    Teachout, Douglas B. [Vista Engineering Technologies, LLC, Richland, Washington, 99352 (United States); Adamson, Clinton J.; Zacharias, Ames [Washington Closure Hanford, LLC, Richland, Washington, 99352 (United States)

    2012-07-01

    The primary objective of a remediation project is the safe extraction and disposition of diverse waste forms and materials. Remediation of a solid waste burial ground containing reactor hardware and irradiated debris involves handling waste with the potential to expose workers to significantly elevated dose rates. Therefore, a major challenge confronted by any remediation project is developing work processes that facilitate compliant waste management practices while at the same time implementing controls to protect personnel. Traditional burial ground remediation is accomplished using standard excavators to remove materials from trenches and other excavation configurations often times with minimal knowledge of waste that will be encountered at a specific location. In the case of the 118-K-1 burial ground the isotopic activity postulated in historic documents to be contained in vertical cylindrical silos was sufficient to create the potential for a significant radiation hazard to project personnel. Additionally, certain reported waste forms posed an unacceptably high potential to contaminate the surrounding environment and/or workers. Based on process knowledge, waste management requirements, historic document review, and a lack of characterization data it was determined that traditional excavation techniques applied to remediation of vertical silos would expose workers to unacceptable risk. The challenging task for the 118-K-1 burial ground remediation project team then became defining an acceptable replacement technology or modification of an existing technology to complete the silo remediation. Early characterization data provided a good tool for evaluating the location of potential high exposure rate items in the silos. Quantitative characterization was a different case and proved difficult because of the large diameter of the silos and the potential for variable density of attenuating soils and waste forms in the silo. Consequently, the most relevant

  2. Detection of Ground Moving Targets for Two-Channel Spaceborne SAR-ATI

    Directory of Open Access Journals (Sweden)

    Diannong Liang

    2010-01-01

    Full Text Available Many present spaceborne synthetic aperture radar (SAR systems are constrained to only two channels for ground moving target indication (GMTI. Along-track interferometry (ATI technique is currently exploited to detect slowly moving targets and measure their radial velocity and azimuth real position. In this paper, based on the joint probability density function (PDF of interferogram's phase and amplitude and the two hypotheses “clutter” and “clutter plus signal”, several constant false alarm rate (CFAR detection criteria are analyzed for their capabilities and limitations under low signal-to-clutter ratio (SCR and low clutter-to-noise ratio (CNR conditions. The CFAR detectors include one-step CFAR detector with interferometric phase, two-step CFAR detectors, and two-dimensional (2D CFAR detector. The likelihood ratio test (LRT based on the Neyman-Pearson (NP criterion is exploited as an upper bound for the performance of the other CFAR detectors. Performance analyses demonstrate the superiority of the 2D CFAR techniques to detect dim slowly moving targets for spaceborne system.

  3. Validation of the use of organic acids and acidified sodium chlorite to reduce Escherichia coli O157 and Salmonella typhimurium in beef trim and ground beef in a simulated processing environment.

    Science.gov (United States)

    Harris, K; Miller, M F; Loneragan, G H; Brashears, M M

    2006-08-01

    A study was conducted to determine if acidified sodium chlorite (1,200 ppm) and acetic and lactic acids (2 and 4%) were effective in reducing foodborne pathogens in beef trim prior to grinding in a simulated processing environment. The reduction of Salmonella Typhimurium and Escherichia coli O157:H7 at high (4.0 log CFU/g) and low (1.0 log CFU/g) inoculation doses was evaluated at various processing steps, including the following: (i) in trim just after treatment application, (ii) in ground beef just after grinding, (iii) in ground beef 24 h after refrigerated storage, (iv) in ground beef 5 days after refrigerated storage, and (v) in ground beef 30 days after frozen storage. All antimicrobial treatments reduced the pathogens on the trim inoculated with the lower inoculation dose to nondetectable numbers in the trim and in the ground beef. There were significant reductions of both pathogens in the trim and in the ground beef inoculated with the high inoculation doses. On the trim itself, E. coli O157:H7 and Salmonella Typhimurium were reduced by 1.5 to 2.0 log cycles, with no differences among all treatments. In the ground beef, the organic acids were more effective in reducing both pathogens than the acidified sodium chlorite immediately after grinding, but after 1 day of storage, there were no differences among treatments. Overall, in the ground beef, there was a 2.5-log reduction of E. coli O157:H7 and a 1.5-log reduction of Salmonella Typhimurium that was sustained over time in refrigerated and frozen storage. Very few sensory differences between the control samples and the treated samples were detected by a consumer panel. Thus, antimicrobial treatments did not cause serious adverse sensory changes. Use of these antimicrobial treatments can be a promising intervention available to ground beef processors who currently have few interventions in their process.

  4. Human Factors Throughout the Life Cycle: Lessons Learned from the Shuttle Program. [Human Factors in Ground Processing

    Science.gov (United States)

    Kanki, Barbara G.

    2011-01-01

    With the ending of the Space Shuttle Program, it is critical that we not forget the Human Factors lessons we have learned over the years. At every phase of the life cycle, from manufacturing, processing and integrating vehicle and payload, to launch, flight operations, mission control and landing, hundreds of teams have worked together to achieve mission success in one of the most complex, high-risk socio-technical enterprises ever designed. Just as there was great diversity in the types of operations performed at every stage, there was a myriad of human factors that could further complicate these human systems. A single mishap or close call could point to issues at the individual level (perceptual or workload limitations, training, fatigue, human error susceptibilities), the task level (design of tools, procedures and aspects of the workplace), as well as the organizational level (appropriate resources, safety policies, information access and communication channels). While we have often had to learn through human mistakes and technological failures, we have also begun to understand how to design human systems in which individuals can excel, where tasks and procedures are not only safe but efficient, and how organizations can foster a proactive approach to managing risk and supporting human enterprises. Panelists will talk about their experiences as they relate human factors to a particular phase of the shuttle life cycle. They will conclude with a framework for tying together human factors lessons-learned into system-level risk management strategies.

  5. Fingerprints of endogenous process on Europa through linear spectral modeling of ground-based observations (ESO/VLT/SINFONI)

    Science.gov (United States)

    Ligier, Nicolas; Carter, John; Poulet, François; Langevin, Yves; Dumas, Christophe; Gourgeot, Florian

    2016-04-01

    . 2011, Dalton et al. 2013). However, the distribution of chlorine species is inconsistent with this process and together with abundance maps of different sizes of crystalline water-ice grain exhibits clear spatial inhomogeneities in their distribution, hence suggesting an endogenous origin for these species. Abundance maps will be presented and the question of the distribution and the formation of these species will be addressed.

  6. Road-Aided Ground Slowly Moving Target 2D Motion Estimation for Single-Channel Synthetic Aperture Radar.

    Science.gov (United States)

    Wang, Zhirui; Xu, Jia; Huang, Zuzhen; Zhang, Xudong; Xia, Xiang-Gen; Long, Teng; Bao, Qian

    2016-03-16

    To detect and estimate ground slowly moving targets in airborne single-channel synthetic aperture radar (SAR), a road-aided ground moving target indication (GMTI) algorithm is proposed in this paper. First, the road area is extracted from a focused SAR image based on radar vision. Second, after stationary clutter suppression in the range-Doppler domain, a moving target is detected and located in the image domain via the watershed method. The target's position on the road as well as its radial velocity can be determined according to the target's offset distance and traffic rules. Furthermore, the target's azimuth velocity is estimated based on the road slope obtained via polynomial fitting. Compared with the traditional algorithms, the proposed method can effectively cope with slowly moving targets partly submerged in a stationary clutter spectrum. In addition, the proposed method can be easily extended to a multi-channel system to further improve the performance of clutter suppression and motion estimation. Finally, the results of numerical experiments are provided to demonstrate the effectiveness of the proposed algorithm.

  7. Road-Aided Ground Slowly Moving Target 2D Motion Estimation for Single-Channel Synthetic Aperture Radar

    Directory of Open Access Journals (Sweden)

    Zhirui Wang

    2016-03-01

    Full Text Available To detect and estimate ground slowly moving targets in airborne single-channel synthetic aperture radar (SAR, a road-aided ground moving target indication (GMTI algorithm is proposed in this paper. First, the road area is extracted from a focused SAR image based on radar vision. Second, after stationary clutter suppression in the range-Doppler domain, a moving target is detected and located in the image domain via the watershed method. The target’s position on the road as well as its radial velocity can be determined according to the target’s offset distance and traffic rules. Furthermore, the target’s azimuth velocity is estimated based on the road slope obtained via polynomial fitting. Compared with the traditional algorithms, the proposed method can effectively cope with slowly moving targets partly submerged in a stationary clutter spectrum. In addition, the proposed method can be easily extended to a multi-channel system to further improve the performance of clutter suppression and motion estimation. Finally, the results of numerical experiments are provided to demonstrate the effectiveness of the proposed algorithm.

  8. Modeling the Inactivation of Intestinal Pathogenic Escherichia coli O157:H7 and Uropathogenic E. coli in Ground Chicken by High Pressure Processing and Thymol.

    Science.gov (United States)

    Chien, Shih-Yung; Sheen, Shiowshuh; Sommers, Christopher H; Sheen, Lee-Yan

    2016-01-01

    Disease causing Escherichia coli commonly found in meat and poultry include intestinal pathogenic E. coli (iPEC) as well as extraintestinal types such as the Uropathogenic E. coli (UPEC). In this study we compared the resistance of iPEC (O157:H7) to UPEC in chicken meat using High Pressure Processing (HPP) in with (the hurdle concept) and without thymol essential oil as a sensitizer. UPEC was found slightly more resistant than E. coli O157:H7 (iPEC O157:H7) at 450 and 500 MPa. A central composite experimental design was used to evaluate the effect of pressure (300-400 MPa), thymol concentration (100-200 ppm), and pressure-holding time (10-20 min) on the inactivation of iPEC O157:H7 and UPEC in ground chicken. The hurdle approach reduced the high pressure levels and thymol doses imposed on the food matrices and potentially decreased food quality damaged after treatment. The quadratic equations were developed to predict the impact (lethality) on iPEC O157:H7 (R (2) = 0.94) and UPEC (R (2) = 0.98), as well as dimensionless non-linear models [Pr > F (<0.0001)]. Both linear and non-linear models were validated with data obtained from separated experiment points. All models may predict the inactivation/lethality within the same order of accuracy. However, the dimensionless non-linear models showed potential applications with parameters outside the central composite design ranges. The results provide useful information of both iPEC O157:H7 and UPEC in regard to how they may survive HPP in the presence or absence of thymol. The models may further assist regulatory agencies and food industry to assess the potential risk of iPEC O157:H7 and UPEC in ground chicken.

  9. Support vector data description for detecting the air-ground interface in ground penetrating radar signals

    Science.gov (United States)

    Wood, Joshua; Wilson, Joseph

    2011-06-01

    In using GPR images for landmine detection it is often useful to identify the air-ground interface in the GRP signal for alignment purposes. A common simple technique for doing this is to assume that the highest return in an A-scan is from the reflection due to the ground and to use that as the location of the interface. However there are many situations, such as the presence of nose clutter or shallow sub-surface objects, that can cause the global maximum estimate to be incorrect. A Support Vector Data Description (SVDD) is a one-class classifier related to the SVM which encloses the class in a hyper-sphere as opposed to using a hyper-plane as a decision boundary. We apply SVDD to the problem of detection of the air-ground interface by treating each sample in an A-scan, with some number of leading and trailing samples, as a feature vector. Training is done using a set of feature vectors based on known interfaces and detection is done by creating feature vectors from each of the samples in an A-scan, applying the trained SVDD to them and selecting the one with the least distance from the center of the hyper-sphere. We compare this approach with the global maximum approach, examining both the performance on human truthed data and how each method affects false alarm and true positive rates when used as the alignment method in mine detection algorithms.

  10. Towards an integrated design of voluntary approaches and standardization processes: An analysis of issues and trends in the Italian regulation on ground coupled heat pumps

    Energy Technology Data Exchange (ETDEWEB)

    Rizzi, Francesco, E-mail: f.rizzi@sssup.it [Scuola Superiore Sant' Anna - Istituto di Management, P.zza Martiri della Liberta 33, 56127 Pisa (Italy); Frey, Marco, E-mail: frey@sssup.it [Scuola Superiore Sant' Anna - Istituto di Management, P.zza Martiri della Liberta 33, 56127 Pisa (Italy); Iraldo, Fabio, E-mail: f.iraldo@sssup.it [Scuola Superiore Sant' Anna - Istituto di Management, P.zza Martiri della Liberta 33, 56127 Pisa (Italy)

    2011-09-15

    Highlights: {yields} We investigate GCHP regulation development from an entrepreneurial perspective. {yields} Threats in booming market orient entrepreneurs toward green management. {yields} Command and control regulation is not sufficient to guarantee market sustainability. {yields} Voluntary regulation encourage best performers to invest in long-term strategies. {yields} Bottom-up regulation design advances integration of process and product standards. - Abstract: Despite the lack of specific incentives, ground coupled heat pump (GCHP) installations are booming in Italy both in the private and public sectors. Such rapid growth is coupled with increasing concern for environmental and technical performances since no comprehensive regulation and reliable standards currently exist. This paper discusses potential schemes aimed at balancing mandatory and voluntary requirements by using SWOT-based techniques and examining the opinions of sectoral leaders. The analysis suggests that standardization and voluntary schemes are perceived as efficient and effective tools to encourage the greening of Italian GCHP-SMEs in the short-term while laying the foundations for sustainable policies in the longer run. A potential scheme is discussed that was simulated by reflecting the supply-side of the market, and which involves process and product standards.

  11. Weighing up the costs of seeking health care for dengue symptoms: a grounded theory study of backpackers' decision-making processes.

    Science.gov (United States)

    Vajta, Bálint; Holberg, Mette; Mills, Jane; McBride, William J H

    2015-01-01

    Dengue fever, a mosquito-borne virus, is an ongoing public health issue in North Queensland. Importation of dengue fever by travellers visiting or returning to Australia can lead to epidemics. The mosquito can acquire the virus in the symptomatic viraemic phase, so timely recognition of cases is important to prevent epidemics. There is a gap in the literature about backpackers' knowledge of dengue fever and the decision-making process they use when considering utilising the Australian health-care system. This study uses grounded theory methods to construct a theory that explains the process backpackers use when seeking health care. Fifty semi-structured interviews with backpackers, hostel receptionists, travel agents and pharmacists were analysed, resulting in identification of a core category: 'weighing up the costs of seeking health care'. This core category has three subcategories: 'self-assessment of health status', 'wait-and-see' and 'seek direction'. Findings from this study identified key areas where health promotion material and increased access to health-care professionals could reduce the risk of backpackers spreading dengue fever.

  12. Analisa Penggunaan Sinyal Radar Bentuk Pulsa dan Gelombang Kontinyu untuk Target Bergerak dengan Model Clutter Terdistribusi Rayleigh

    Directory of Open Access Journals (Sweden)

    Fery Gustomo

    2013-09-01

    Full Text Available Radar (Radio, Detection, and Ranging mampu mendeteksi target untuk mendapatkan informasi berupa jarak, azimuth, dan kecepatan. Sinyal Radar ada dua jenis, yaitu pulsa (Pulsed Radar dan gelombang kontinyu (Continuous Wave Radar. Pulsed Radar mempunyai prinsip kerja memancarkan sinyal pulsa dengan PRI (Pulse Repetition Interval dan PRF (Pulse Repetition Frequency tertentu dipancarkan dengan modulasi ke dalam sinyal sinusoidal dengan frekuensi yang lebih tinggi serta memanfaatkan delay dari setiap pulsanya untuk mendapatkan informasi dari target. Sedangkan Continuous Wave Radar mempunyai prinsip kerja memancarkan sinyal sinusoidal secara terus menerus dan memanfaatkan sinyal echo yang terdiri dari beberapa variasi frekuensi akibat adanya efek Doppler untuk mendeteksi target. Terdapat pengaruh jenis gelombang sinyal radar terhadap kemampuan deteksi radar. Model distribusi Rayleigh dipilih untuk dapat mewakili suatu kondisi lingkungan (clutter yang bergerak dan mempunyai parameter kecepatan angin. Hasil simulasi dari kedua jenis sinyal menunjukkan bahwa pada model clutter terdistribusi Rayleigh, radar CW mempunyai kemampuan deteksi yang lebih baik pada kecepatan target yang lebih tinggi, karena mampu mendeteksi target dengan kecepatan 20-60 knots. Sedangkan radar pulsa mempunyai kemampuan deteksi yang lebih baik pada kecepatan target rendah yaitu pada kecepatan 15-55 knots. Untuk Probabilitas deteksi minimum 90%, Radar CW mempunyai ketahanan yang lebih baik terhadap noise daripada radar pulsa karena kemampuan radar pulsa terbatas pada nilai SNR 20 dB. Sedangkan radar CW mampu mendeteksi target dengan baik sampai SNR bernilai 15 dB. Sedangkan untuk deteksi terhadap kecepatan target, radar CW mempunyai hasil yang lebih akurat daripada radar pulsa.

  13. Joint statistical correction of clutters, spokes and beam height for a radar derived precipitation climatology in southern Germany

    Directory of Open Access Journals (Sweden)

    A. Wagner

    2012-11-01

    Full Text Available First results of radar derived climatology have emerged over the last years, as datasets of appropriate extent are becoming available. Usually, these statistics are based on time series lasting up to ten years as continuous storage of radar data was often not achieved before. This kind of climatology demands a high level of data quality. Small deviations or minor systematic under- or overestimations in single radar images become a major cause of error in statistical analysis. Extensive corrections of radar data are a crucial prerequisite for radar derived climatology. We present a new statistical post-correction scheme based on a climatological analysis of seven years of radar data of the Munich weather radar (2000–2006 operated by DWD (German Weather Service. Original radar products are used subject only to corrections within the signal processor without any further corrections on single radar images. The aim of this statistical correction is to make up for the average systematic errors caused by clutter, propagation, or measuring effects but to conserve small-scale natural variations in space.

    The statistical correction is based on a thorough analysis of the different causes of possible errors for the Munich weather radar. This analysis revealed the following basic effects: the decrease of rain amount as a function of height and distance from the radar, clutter effects such as clutter remnants after filtering, holes by eliminated clutter or shading effects from obstacles near the radar, visible as spokes, as well as the influence of the bright band. The correction algorithm is correspondingly based on these results. It consists of three modules. The first one is an altitude correction which minimises measuring effects. The second module corrects clutter effects and disturbances and the third one realises a mean adjustment to selected rain gauges. Two different sets of radar products are used. The statistical analysis as well as

  14. [Solidification/Stabilization of Chromite Ore Processing Residue (COPR) Using Zero-Valent Iron and Lime-Activated Ground Granulated Blast Furnace Slag].

    Science.gov (United States)

    Chen, Zhong-lin; Li, Jin-chunzi; Wang, Bin-yuan; Fan, Lei-tao; Shen, Ji-min

    2015-08-01

    The solidification/stabilization (S/S) of chromite ore processing residue (COPR) was performed using zero-valent iron (ZVI) and lime-activated ground granulated blast furnace slag (GGBFS). The degree of Cr immobilization was evaluated using the leaching procedure, mineral composition analysis and morphology analysis. Semi-dynamic leaching tests were implemented to investigate the potential for reusing the final treatment product as a readily available construction material. The results showed that after reduction, all of the S/S treated COPR samples met the pollution control limit of bricks and building block products (Chinese standard HJ/T 301-2007) produced with COPR for total Cr (0.3 mg x L(-1)), the compressive strength of all the S/S samples could meet the compressive strength standard (15 MPa) for producing clay bricks, and Cr existed as the specie that bound to Fe/Mn oxides in the S/S samples. At the same time, all of the S/S treated specimens tested were suitable for utilization at certain levels.

  15. Collection, processing, and interpretation of ground-penetrating radar data to determine sediment thickness at selected locations in Deep Creek Lake, Garrett County, Maryland, 2007

    Science.gov (United States)

    Banks, William S.L.; Johnson, Carole D.

    2011-01-01

    The U.S. Geological Survey collected geophysical data in Deep Creek Lake in Garrett County, Maryland, between September 17 through October 4, 2007 to assist the Maryland Department of Natural Resources to better manage resources of the Lake. The objectives of the geophysical surveys were to provide estimates of sediment thickness in shallow areas around the Lake and to test the usefulness of three geophysical methods in this setting. Ground-penetrating radar (GPR), continuous seismic-reflection profiling (CSP), and continuous resistivity profiling (CRP) were attempted. Nearly 90 miles of GPR radar data and over 70 miles of CSP data were collected throughout the study area. During field deployment and testing, CRP was determined not to be practical and was not used on a large scale. Sediment accumulation generally could be observed in the radar profiles in the shallow coves. In some seismic profiles, a thin layer of sediment could be observed at the water bottom. The radar profiles appeared to be better than the seismic profiles for the determination of sediment thickness. Although only selected data profiles were processed, all data were archived for future interpretation.

  16. 面向GPU快速处理的地面材质数据压缩方法%Ground Material Data Compression Method for GPU Rapid Processing

    Institute of Scientific and Technical Information of China (English)

    陆巍巍; 徐涛; 徐珂文

    2015-01-01

    To solve the problems of saving and loading of mass ground materiel data in radar imaging simulation, an adap?tive max run length coding and modified pairing based algorithm is proposed for data compression. It reduces the amount of data in storage, and eliminates bottleneck of data flow. The compression algorithm is designed for GPU rapid processing, so the compressed data can be decompressed in GPU effectively.%为解决雷达图像仿真中海量地面材质数据的存储和加载问题,采用基于自适应最大行程长度编码和修正偶对的压缩算法进行材质数据的压缩,从而有效地减少了数据的存储量,消除数据传输的瓶颈,提高了数据传输的吞吐能力.压缩算法面向GPU快速处理,得到压缩数据适用于GPU进行快速解压.

  17. Measurement of ground state properties of neutron-rich nuclei on the r-process path between the N=50 and N=82 shells

    CERN Multimedia

    2007-01-01

    The evolution of the unknown ground-state ${\\beta}$-decay properties of the neutron-rich $^{84-89}$Ge, $^{90-93}$Se and $^{102-104}$Sr isotopes near the r-process path is of high interest for the study of the abundance peaks around the N=50 and N=82 neutron shells. At ISOLDE, beams of certain elements with sufficient isotopic purity are produced as molecular sidebands rather than atomic beams. This applies e.g, to germanium, separated as GeS$^{+}$, selenium separated as SeCO$^{+}$ and strontium separated as SrF$^{+}$. However, in case of neutron-rich isotopes produced in actinide targets, new "isobaric" background of atomic ions appears on the mass of the molecular sideband. For this particular case, the ECR charge breeder, positioned in the experimental hall after ISOLDE first mass separation, can be advantageously used as a purification device, by breaking the molecules and removing the molecular contaminants. This proposal indicates our interest in the study of basic nuclear structure properties of neutron...

  18. 'Grounded' Politics

    DEFF Research Database (Denmark)

    Schmidt, Garbi

    2012-01-01

    play within one particular neighbourhood: Nørrebro in the Danish capital, Copenhagen. The article introduces the concept of grounded politics to analyse how groups of Muslim immigrants in Nørrebro use the space, relationships and history of the neighbourhood for identity political statements....... The article further describes how national political debates over the Muslim presence in Denmark affect identity political manifestations within Nørrebro. By using Duncan Bell’s concept of mythscape (Bell, 2003), the article shows how some political actors idealize Nørrebro’s past to contest the present...

  19. A grounded theory approach to understand the process of decision making on fertility control methods in urban society of Mashhad, Iran.

    Science.gov (United States)

    Roudsari, Robab Latifnejad; Khadivzadeh, Talat; Bahrami, Masoud

    2013-09-01

    More than 30% of pregnancies in Iran are unintended and most of them happen among the women who use various contraceptive methods. Results of Integrated Monitoring and Evaluation System (IMES) showed that the rate of innovative contraceptive use in Mashhad has been 41.5%-57% in different urban areas. This study was conducted to explore the process of making decision toward using family planning methods in women of reproductive age in urban society of Mashhad, Iran. In this grounded theory study, semi-structured interviews were conducted with 45 purposefully selected participants including 28 women and 17 key informants including family health providers and managers, and participants' mothers and husbands, who lived in urban society of Mashhad, Iran, in 2011-2012. Participants' recruitment continued until data saturation occurred. Data were analyzed using Strauss and Corbin's mode of analysis through constant comparative method, applying levels of open, axial, and selective coding with MAXqda software. Study rigor was confirmed through prolonged engagement, member check, expert debriefing, and thick description of the data. The core category of "caring the comprehensive health of my family," which emerged from the data, described the process of couples' decision making toward using family planning methods in this study. Other developed categories which were presented into a theoretical scheme consisted of 1) shaping the ideas of fertility control, 2) developing cognition about the fertility control methods, 3) appraising available choices and choosing the most appropriate one, 4) managing the course of using methods, and 5) realizing the fertility intentions. It is important that family planning providers understand the motivations, perceptions, and knowledge of women about contraceptive methods in their contextual situation, which illustrates their mode of interaction in the arenas of family planning decision making.

  20. Modeling and Simulation of High Resolution Radar Clutter on SIRV%基于SIRV高分辨率雷达杂波建模与仿真

    Institute of Scientific and Technical Information of China (English)

    谢洪森; 周鹏; 栾宝宽; 邹鲲

    2012-01-01

    Modeling and simulation of the high resolution radar clutter is the most important method to evaluate the radar performance. The generalized compound (GO probability density function(PDF) is used to describe the high resolution radar clutter statistics. The GC PDF is formed using the generalized gamma PDF to describe the speckle and modulation components of the radar clutter. The advantageous of radar clutter modeling by use of spherically invariant random vector (SIRV) is that the correlation matrix and marginal PDF of random vectors can be control respectively and independently. In this paper, the GC PDF radar clutter and SIRV modeling methods are discussed, and the SIRV model of the GC PDF radar clutter is proposed. The computer simulation is used to validate the model, and the statistics of the simulated GC-PDF clutter is compared with the theoretical results. The simulation results are identical with the theoretical results, which proves that the SIRV model is of availability and universality.%高分辨率雷达杂波建模与仿真是评估雷达性能的重要手段.广义复合概率密度通常用来描述高分辨率雷达杂波.在广义复合分布中,将散斑分量和调制分量均采用广义伽马(GΓ)分布来表示.采用球不变随机矢量(SIRV)进行杂波建模的优点在于能够独立控制其相关性和一维边缘概率密度.对广义复合分布和SIRV建模方法进行了讨论,在此基础上,给出了相干相关的广义复合分布的SIRV模型,利用计算机进行了广义复合分布的杂波仿真,并对杂波仿真的统计特性与理论值进行了比较.仿真结果与理论分析相吻合,说明了该模型的有效性和普适性.

  1. Simulating the thermal operating conditions in the thermal wells of ground-source heat-pump heat supply systems. Part I: Porous moisture freezing processes in soil

    Science.gov (United States)

    Vasilyev, G. P.; Peskov, N. V.; Lichman, V. A.; Gornov, V. F.; Kolesova, M. V.

    2015-08-01

    The mathematical models laid down in the new blocks of the INSOLAR.GSHP.12 software system simulating unsteady operating conditions of ground-source heat-pump (GSHP) heat supply systems are presented. The new model blocks take into account the effect the freezing of porous moisture in soil has on the GSHP system performance efficiency. Illustration is given to the need of taking into account the porous moisture freezing/thawing processes in soil, and the results from investigations devoted to the opening possibilities of constructing adaptive GSHP systems with controlled intensity of heat transfer in the soil-thermal well system are presented. The development of software simulating the porous moisture phase state variation processes in soil was preceded by development of mathematical equations representing the thermal conditions of soil body involving porous moisture freezing/thawing processes. A description of these equations is also given in the article. In constructing the mathematical model, the notion "effective thermal conductivity" of soil was introduced for taking into account the latent heat of phase transition that releases during the freezing of moisture. The above-mentioned effective thermal conductivity of soil involves two components: the soil thermal conductivity coefficient itself and an additional term modifying the thermal conductivity value for taking into account the influence of phase transition. For quantitatively evaluating the soil effective thermal conductivity component that takes into account the influence of phase transition, the soil freezing zone radius around the thermal well was determined. The obtained analytic solutions have been implemented in the form of computer program blocks, after which a "numerical experiment" was carried out for estimating the effect the porous moisture freezing/thawing processes have on the soil thermal conditions. It was demonstrated during that experiment that the soil thermal conductivities determined

  2. Modeling Water and Nutrient Transport through the Soil-Root-Canopy Continuum: Explicitly Linking the Below- and Above-Ground Processes

    Science.gov (United States)

    Kumar, P.; Quijano, J. C.; Drewry, D.

    2010-12-01

    Vegetation roots provide a fundamental link between the below ground water and nutrient dynamics and above ground canopy processes such as photosynthesis, evapotranspiration and energy balance. The “hydraulic architecture” of roots, consisting of the structural organization of the root system and the flow properties of the conduits (xylem) as well as interfaces with the soil and the above ground canopy, affect stomatal conductance thereby directly linking them to the transpiration. Roots serve as preferential pathways for the movement of moisture from wet to dry soil layers during the night, both from upper soil layer to deeper layers during the wet season (‘hydraulic descent’) and vice-versa (‘hydraulic lift’) as determined by the moisture gradients. The conductivities of transport through the root system are significantly, often orders of magnitude, larger than that of the surrounding soil resulting in movement of soil-moisture at rates that are substantially larger than that through the soil. This phenomenon is called hydraulic redistribution (HR). The ability of the deep-rooted vegetation to “bank” the water through hydraulic descent during wet periods for utilization during dry periods provides them with a competitive advantage. However, during periods of hydraulic lift these deep-rooted trees may facilitate the growth of understory vegetation where the understory scavenges the hydraulically lifted soil water. In other words, understory vegetation with relatively shallow root systems have access to the banked deep-water reservoir. These inter-dependent root systems have a significant influence on water cycle and ecosystem productivity. HR induced available moisture may support rhizosphere microbial and mycorrhizal fungi activities and enable utilization of heterogeneously distributed water and nutrient resources To capture this complex inter-dependent nutrient and water transport through the soil-root-canopy continuum we present modeling

  3. EXTRACTING A RADAR REFLECTION FROM A CLUTTERED ENVIRONMENT USING 3-D INTERPRETATION

    Science.gov (United States)

    A 3-D Ground Penetrating Radar (GPR) survey at 50 MHz center frequency was conducted at Hill Air Force Base, Utah, to define the topography of the base of a shallow aquifer. The site for the survey was Chemical Disposal Pit #2 where there are many man-made features that generate ...

  4. EXTRACTING A RADAR REFLECTION FROM A CLUTTERED ENVIRONMENT USING 3-D INTERPRETATION

    Science.gov (United States)

    A 3-D Ground Penetrating Radar (GPR) survey at 50 MHz center frequency was conducted at Hill Air Force Base, Utah, to define the topography of the base of a shallow aquifer. The site for the survey was Chemical Disposal Pit #2 where there are many man-made features that generate ...

  5. Sensitivity Study of Cross-Atlantic Dust Transport to Dust Emissions, Chemical Aging and Removal Processes and Comparison with Ground and Satellite Data

    Science.gov (United States)

    Abdelkader, Mohamed; Metzger, Swen; Klingmüller, Klaus; Steil, Benedikt; Lelieveld, Jos

    2016-04-01

    -range transport. The comparison of the EMAC results with ground-based observations (AERONET, CASTNET, EMEP), as well as various satellite data (MODIS, MISR and CALIPSO) shows that uncertainties associated with the calculation of the dust transport into the Caribbean reduces by considering the dust aging processes.

  6. Ground-based LiDAR application to characterize sea cliff instability processes along a densely populated coastline in Southern Italy

    Science.gov (United States)

    Esposito, Giuseppe; Semaan, Fouad; Salvini, Riccardo; Troise, Claudia; Somma, Renato; Matano, Fabio; Sacchi, Marco

    2017-04-01

    Sea cliff retreatment along the coastline of the Campi Flegrei volcanic area (Southern Italy) is becoming a threat for public and private structures due to the massive urbanization occurred in the last few decades. In this area, geological features of the outcropping rocks represent one of the most important factors conditioning the sea cliff retreatment. In fact, pyroclastic deposits formed by pumices, scoria, ashes and lapilli are arranged in weakly to moderately welded layers of variable thicknesses, resulting very erodible and prone to landslide processes. Available methods to evaluate topographic changes and retreat rates of sea cliffs include a variety of geomatic techniques, like terrestrial and aerial photogrammetry and LiDAR (Light Detection And Ranging). By means of such techniques, it is in fact possible to obtain high resolution topography of sea cliffs and perform multi-temporal change detection analysis. In this contribution, we present an application of Terrestrial Laser Scanning (TLS or ground-based LiDAR) aimed to identify and quantify instability processes acting along the Torrefumo coastal cliff, in the Campi Flegrei area. Specifically, we acquired a series of 3D point clouds on the years 2013 and 2016, and compared them through a cloud-to-cloud distance computation. Furthermore, a statistical analysis was applied to the change detection results. In this way, an inventory of the cliff failures occurred along the Torrefumo cliff in the 2013-2016 time span was created, as well as the spatial and volumetric distribution of these failures was evaluated. The volumetric analysis shows that large collapses occurred rarely, whereas the spatial analysis shows that the majority of failures occurred in the middle and upper parts of the cliff face. Results also show that both rock fall and surficial erosion processes contribute to the cliff retreatment, acting in turn according to the geological properties of the involved pyroclastic deposits. The presented

  7. Geological and Geophysical Analysis of the Processes Ground Cracking and Associated Risks in Urban Basins in the Eastern and Northern of Jalisco Block, Mexico.

    Science.gov (United States)

    Suarez-Plascencia, C.

    2016-12-01

    The Jalisco Block (JB) is located in the western sector of Mexican Volcanic Belt; it is bounded on the east by the Colima graben-Zacoalco and apparently the north by the River Grande de Santiago. Three landform are regionally identified: mountain areas, piedmont and plains formed by deposits of tuffs, volcanic ash and sediment filled. These plains have been progressively urbanized since the sixteenth century; they were built in around the Guadalajara Metropolitan Area, as well as small towns like Sayula, Ciudad Guzman, Zacoalco, Jocotepec and nearby villages, in which all together are populated by about 6 million people. Since 1912 there are records of damages by the continuous formation of ground cracking, this process has increased over the past two decades, affecting natural soil, agricultural areas, urban areas and infrastructure of roads and highways. These cracks generally have a SW-NE orientation similar with the alignment of regional geological structures. They are characterized by settlements and forming steps of a few centimeters, with lengths from 300 to 1000 m and depths of a few centimeters to 15 meters and width of up to 2.5 m. Formed mainly during the rainy season from June to October each year. Recent damages have generated losses of several hundreds of thousands of dollars, especially in Ciudad Guzman, located in southern BJ, where a crack of 2.5 km was observed in 2012 and it has long affected the downtown area, the town of Nextipac-Tesistan, municipality of Zapopan in the northern sector of JB. This territory is formed by a thick deposit of pumice tuffs, which has presented cracks in the years 1912, 1975, 1987, 2004 and 2015, affecting also agricultural and urban areas. The paper will presents results which will analyze and discern through geological, geophysical and with technology of geographic information, the origin of these cracks, which can be associated with active tectonic structures, geo-hydrological processes, extraction of underground

  8. Threat of the feminine identity: The emerging structure in exploring the process of women's empowerment for menopause management: A grounded theory study

    Directory of Open Access Journals (Sweden)

    Mansoureh Yazdkhasti

    2016-11-01

    Full Text Available Women empowerment in different spheres of life especially menopause is among the key elements of health promotion in all communities. However there is no realistic images of empowering women in menopausal symptoms management. The present survey aimed to explain the process of women's empowerment for menopausal symptoms management. This qualitative study is part of a larger project which was conducted using Grounded Theory between 2013 and 2015. The article's main focus was to explore the underlying conditions and factors affecting the process of women's empowerment. Using a purposive and theoretical sampling method, 25 participants were interviewed 28 times. Data was collected through some in-depth, semi-structural and open ended interviews with the participant and also memoing and field notes. The interviews were conducted in Neighborhoods House affiliated to Tehran municipality and two gynecological clinics affiliated to Tehran University of Medical Sciences. Data analysis was applied through Strauss and Corbin approach (2008 using MAXQDA10 software. Threat of the feminine identity has been noted as the women's most common concern to being empowered in menopause management. The key theme emerged in the present study (threat of the feminine identity included four main categories (consciousness about the likelihood of femininity decline, negative attitude towards herself, inadequate supportive context, latent opportunity, two subcategories and 109 first-level codes. There is a logical, coherent and integrated relationship between all these concepts and the theme of feminine identity threat. This theme is considered as an underlying social problem and a major concern for postmenopausal women in the context of this group of women's empowerment. The factors (barriers and facilitators affecting women's empowerment in menopause management are associated with social context, intensity and origin of each society. Evaluation of Iranian women

  9. No consistent effect of plant species richness on resistance to simulated climate change for above- or below-ground processes in managed grasslands.

    Science.gov (United States)

    Dormann, Carsten F; von Riedmatten, Lars; Scherer-Lorenzen, Michael

    2017-06-17

    Species richness affects processes and functions in many ecosystems. Since management of temperate grasslands is directly affecting species composition and richness, it can indirectly govern how systems respond to fluctuations in environmental conditions. Our aim in this study was to investigate whether species richness in managed grasslands can buffer the effects of drought and warming manipulations and hence increase the resistance to climate change. We established 45 plots in three regions across Germany, each with three different management regimes (pasture, meadow and mown pasture). We manipulated spring warming using open-top chambers and summer drought using rain-out shelters for 4 weeks. Measurements of species richness, above- and below-ground biomass and soil carbon and nitrogen concentrations showed significant but inconsistent differences among regions, managements and manipulations. We detected a three-way interaction between species richness, management and region, indicating that our study design was sensitive enough to detect even intricate effects. We could not detect a pervasive effect of species richness on biomass differences between treatments and controls, indicating that a combination of spring warming and summer drought effects on grassland systems are not consistently moderated by species richness. We attribute this to the relatively high number of species even at low richness levels, which already provides the complementarity required for positive biodiversity-ecosystem functioning relationships. A review of the literature also indicates that climate manipulations largely fail to show richness-buffering, while natural experiments do, suggesting that such manipulations are milder than reality or incur treatment artefacts.

  10. Analysis of calibrated sea clutter and boat reflectivity data at C- and X-band in South African coastal waters

    CSIR Research Space (South Africa)

    Herselman, PLR

    2007-10-01

    Full Text Available , southwest of the deployment site which is located in a small bay area with a sea bed depth varying between 10 – 30 m at ranges of 3 and 10 km respectively. The ground truth tracks of the boats were estimated using a differential processing Global... below a helicopter, tracked in range with a typical α-β tracker and in angle with a video centroid tracker, was measured and the calibration coefficient was calculated as [ ] ( ) ( ) ( ) ,,10log20 1 4 1 1 1 max max...

  11. A radar unattended ground sensor with micro-Doppler capabilities for false alarm reduction

    Science.gov (United States)

    Tahmoush, Dave; Silvious, Jerry; Burke, Ed

    2010-10-01

    Unattended ground sensors (UGS) provide the capability to inexpensively secure remote borders and other areas of interest. However, the presence of normal animal activity can often trigger a false alarm. Accurately detecting humans and distinguishing them from natural fauna is an important issue in security applications to reduce false alarm rates and improve the probability of detection. In particular, it is important to detect and classify people who are moving in remote locations and transmit back detections and analysis over extended periods at a low cost and with minimal maintenance. We developed and demonstrate a compact radar technology that is scalable to a variety of ultra-lightweight and low-power platforms for wide area persistent surveillance as an unattended, unmanned, and man-portable ground sensor. The radar uses micro-Doppler processing to characterize the tracks of moving targets and to then eliminate unimportant detections due to animals as well as characterize the activity of human detections. False alarms from sensors are a major liability that hinders widespread use. Incorporating rudimentary intelligence into sensors can reduce false alarms but can also result in a reduced probability of detection. Allowing an initial classification that can be updated with new observations and tracked over time provides a more robust framework for false alarm reduction at the cost of additional sensor observations. This paper explores these tradeoffs with a small radar sensor for border security. Multiple measurements were done to try to characterize the micro-Doppler of human versus animal and vehicular motion across a range of activities. Measurements were taken at the multiple sites with realistic but low levels of clutter. Animals move with a quadrupedal motion, which can be distinguished from the bipedal human motion. The micro-Doppler of a vehicle with rotating parts is also shown, along with ground truth images. Comparisons show large variations for

  12. Classification of artificial (man-made) ground

    OpenAIRE

    Rosenbaum, M.S.; McMillan, A.A.; Powell, J H; Cooper, A.H.; Culshaw, M.G.; Northmore, K.J.

    2003-01-01

    The legacy inherited from anthropogenic processes needs to be addressed in order to provide reliable and up-to-date ground information relevant to development and regeneration in the urban environment. The legacy includes voids as well as anthropogenic deposits (artificial ground). Their characteristics derive from former quarrying and mining activities, industrial processes creating derelict ground, variably consolidated made ground, and contaminated groundwater and soils. All need to be sys...

  13. Observations on syntactic landmine detection using impulse ground-penetrating radar

    Science.gov (United States)

    Nasif, Ahmed O.; Hintz, Kenneth J.

    2011-06-01

    We discuss some results and observations on applying syntactic pattern recognition (SPR) methodology for landmine detection using impulse ground-penetrating radar (GPR). In the SPR approach, the GPR A-scans are first converted into binary-valued strings by inverse filtering, followed by concavity detection to identify the peaks and valleys representing the locations of impedance discontinuities in the return signal. During the training phase, the characteristic binary strings for a particular landmine are found by looking at all the exemplars of that mine and selecting the collection of strings that yield the best detection results on these exemplars. These characteristic strings can be detected very efficiently using finite state machines (FSMs). Finally, the FSM detections are clustered to assign confidence to each detection, and discard sparse detections. Provided that the impulse GPR provides enough resolution in range, the SPR method can be a robust and high-speed solution for landmine detection and classification, because it aims to exploit the impedance discontinuity profile of the target, which is a description of the internal material structure of the target and little affected by external clutter. To evaluate the proposed methodology, the SPR scheme is applied to a set of impulse GPR data taken at a government test site. We suggest that coherent frequency-agile radar may be a better option for the SPR approach, since it addresses some of the drawbacks of a non-coherent impulse GPR caused by internally non-coherent within-channel signals which necessitate non-coherent integration and its attendant longer integration times, and non-coherent adjacent channels which severely limit the ability to do spatial, or at a minimum, cross-range processing if the GPR is in a linear array antenna.

  14. Raw and processed ground-penetrating radar and postprocessed differential global positioning system data collected from Assateague Island, Maryland, October 2014

    Science.gov (United States)

    Zaremba, Nicholas J.; Bernier, Julie C.; Forde, Arnell S.; Smith, Christopher G.

    2016-06-08

    Scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center acquired sediment cores, sediment surface grab samples, ground-penetrating radar (GPR) and Differential Global Positioning System (DGPS) data from Assateague Island, Maryland, in October 2014. The objectives were to identify washover deposits in the stratigraphic record to aid in understanding barrier island evolution.

  15. PRODUCT SAFETY AND COLOR CHARACTERISTICS OF GROUND BEEF PROCESSED FROM BEEF TRIMMINGS TREATED WITH PEROXYACETIC ACID ALONE OR FOLLOWED BY NOVEL ORGANIC ACIDS

    Directory of Open Access Journals (Sweden)

    Fred Pohlman

    2014-10-01

    Full Text Available The objective of this study was to evaluate the effectiveness of antimicrobial interventions using peroxyacetic acetic acid (PAA followed by novel organic acids on beef trimmings prior to grinding with conventional spray (CS or electrostatic spray (ES on ground beef microbial populations and color. Beef trimmings (80/20; 25kg were inoculated with E. coli O157:H7, non- O157:H7 shiga toxin producing (STEC E. coli (EC and Salmonella spp. (SA at 105 CFU/g. Inoculated trimmings (1.5 kg /treatment/replicate, 2 replicates were treated with CS application of 0.02% PAA alone or followed by CS or ES application of 3% octanoic acid (PO, 3% pyruvic acid (PP, 3% malic acid (PM, saturated solution of fumaric acid (PF or deionized water (W. Findings from this study suggest that PA as a single or multiple chemical hurdle approach with malic, pyruvic, octanoic and fumaric acid on beef trimmings may be effective in reducing E. coli O157:H7 as well as non-STEC serotypes and Salmonella in ground beef up to day 2 of simulated retail display. Results of this study showed that instrumental color properties of ground beef treated with peroxyacetic acid followed by organic acids had little or no difference (P > 0.05 compared to the untreated un-inoculated control ground beef samples. The results also indicate that ES application of some organic acids may have similar or greater efficiency in controlling ground beef microbial populations compared to the CS application of the same acid providing a more economical and waste manageable decontamination approach.

  16. MCMC Particle Filter Using New Data Association Technique with Viterbi Filtered Gate Method for Multi-Target Tracking in Heavy Clutter

    Directory of Open Access Journals (Sweden)

    E. M.Saad

    2011-08-01

    Full Text Available Improving data association technique in dense clutter environment for multi-target tracking used in Markov chain Monte Carlo based particle filter (MCMC-PF are discussed in this paper. A new method named Viterbi filtered gate Markov chain Monte Carlo VFG-MCMC is introduced to avoid track swap and to overcome the issue of loosing track to highly maneuvering targets in the presence of more background clutter and false signals. An adaptive search based on Viterbi algorithm is then used to detect the valid filtered data point in each target gate. The detected valid point for each target is applied to the estimation algorithm of MCMC-PF during calculating the sampling weights. This proposed method makes the MCMC interacts only with the valid target that is candidate from the filtered gate and no more calculations are considered for invalid targets. Simulation results demonstrate the effectiveness and better performance when compared to conventional algorithm MCMC-PF.

  17. Automated Ground Penetrating Radar hyperbola detection in complex environment

    Science.gov (United States)

    Mertens, Laurence; Lambot, Sébastien

    2015-04-01

    Ground Penetrating Radar (GPR) systems are commonly used in many applications to detect, amongst others, buried targets (various types of pipes, landmines, tree roots ...), which, in a cross-section, present theoretically a particular hyperbolic-shaped signature resulting from the antenna radiation pattern. Considering the large quantity of information we can acquire during a field campaign, a manual detection of these hyperbolas is barely possible, therefore we have a real need to have at our disposal a quick and automated detection of these hyperbolas. However, this task may reveal itself laborious in real field data because these hyperbolas are often ill-shaped due to the heterogeneity of the medium and to instrumentation clutter. We propose a new detection algorithm for well- and ill-shaped GPR reflection hyperbolas especially developed for complex field data. This algorithm is based on human recognition pattern to emulate human expertise to identify the hyperbolas apexes. The main principle relies in a fitting process of the GPR image edge dots detected with Canny filter to analytical hyperbolas, considering the object as a punctual disturbance with a physical constraint of the parameters. A long phase of observation of a large number of ill-shaped hyperbolas in various complex media led to the definition of smart criteria characterizing the hyperbolic shape and to the choice of accepted value ranges acceptable for an edge dot to correspond to the apex of a specific hyperbola. These values were defined to fit the ambiguity zone for the human brain and present the particularity of being functional in most heterogeneous media. Furthermore, the irregularity is particularly taken into account by defining a buffer zone around the theoretical hyperbola in which the edge dots need to be encountered to belong to this specific hyperbola. First, the method was tested in laboratory conditions over tree roots and over PVC pipes with both time- and frequency-domain radars

  18. Robust design of multiple-input multiple-output radar waveform covariance matrix in the presence of clutter

    Science.gov (United States)

    Guo, Rongyan; Wang, Hongyan

    2016-07-01

    In this work, the issue of robust waveform optimization is addressed in the presence of clutter to improve the worst-case estimation accuracy for collocated multiple-input multiple-output (MIMO) radar. Robust design is necessary due to the fact that waveform design may be sensitive to uncertainties in the initial parameter estimates. Following the min-max approach, the robust waveform covariance matrix design is formulated here on the basis of Cramér-Rao Bound to ease this sensitivity systematically for improving the worst-case accuracy. To tackle the resultant complicated and nonlinear problem, a new diagonal loading (DL)-based iterative approach is developed, in which the inner optimization problem can first be decomposed to some independent subproblems by using the Hadamard's inequality, and then these subproblems can be reformulated into convex issues by using DL method, as well as the outer optimization problem can also be relaxed to a convex issue by translating the nonlinear function into a linear one, and, hence, both of them can be solved very effectively. An optimal solution to the original problem can be obtained via the least-squares fitting of the solution acquired by the iterative approach. Numerical simulations show the efficiency of the proposed method.

  19. Hyperspectral Imaging and Association Phenomenology of Pedestrians in a Cluttered Urban Environment

    Science.gov (United States)

    Herweg, Jared A.

    Remote hyperspectral imaging (HSI) has shown promise in several applications such as object detection and tracking. Typically research has focused on large objects, such as vehicles, for tracking due to the spatial resolution of current operational HSI systems. This research seeks to extend the utility of applying HSI to human pedestrian detection using the reflective solar spectral range between 400 - 2500 nm. A phenomenological investigation of a novel scheme to differentiate between pedestrians is studied. By applying the basics of detection theory, this research focuses on being able to differentiate between pedestrians, as well as background materials. Specifically, this research explores the likelihood of detecting and differentiating pedestrians based on four defined subregions comprised of the exposed hair, skin, and the fabrics used for shirts and trousers. The scope of this work encompassed detecting a pedestrian of interest outdoors among other pedestrians in an urban environment consisting of a mixture of asphalt, concrete, grass, and trees. Two unique datasets were created during the course of this effort. One dataset was a collection of fully ground-truthed hyperspectral images of pedestrians in an urban environment. A second dataset was a synthetic rendering of the real-world ground truthed pedestrian scene developed using the Digital Imaging and Remote Sensing Image Generation (DIRSIG) model. Subregion separability analysis results, using spectral reflectance data, provided strong evidence that combining the observable spectral features of detectable subregions is a viable means of distinguishing between pedestrians. Further analysis using real-world HSI data demonstrated that the detection and classification of the pedestrian subregions when changes in illumination, location, and background occur within the field of view of a hyperspectral sensor is achievable with a greater than 60% accuracy. In addition to the direct detection and association

  20. Bistatic MIMO Radar Clutter Suppression by Exploiting the Transmit Angle%利用发射角度的双基地MIMO雷达杂波抑制方法

    Institute of Scientific and Technical Information of China (English)

    李军; 党博; 刘长赞; 廖桂生

    2014-01-01

    双基地雷达中引入多输入多输出(MIMO)技术,可以从接收数据中获取双基地雷达发射角度信息。这一新增的角度信息用于空时自适应处理,获得发射空间-接收空间和多普勒3维杂波谱。该文旨在对双基地MIMO雷达空时自适应处理抑制杂波方法进行综述。首先介绍了双基地MIMO雷达信号模型,然后介绍了几种正侧视双基地MIMO雷达空时3维自适应处理方法(3D-STAP),包括3维线性最小方差(3D-LCMV)方法、3维辅助通道方法、3维局域化联合处理以及3维投影的空时3维降维杂波抑制方法,仿真分析表明这些降维方法能够有效提高小样本条件下的双基地MIMO雷达距离依赖杂波抑制性能。最后,对双基地MIMO雷达空时自适应处理研究做了总结和展望。%The transmit angle of bistatic radars can be obtained by introducing Multiple-Input Multiple-Output (MIMO) radar techniques. The Three-Dimensional (3D) clutter spectra, that is, the transmit angle, receive angle, and Doppler frequency, are introduced using the additional angle information to Space-Time Adaptive Processing (STAP). This study reviews the researches on bistatic MIMO-STAP. 3D space-time adaptive processing methods for airborne bistatic side-looking MIMO radars, such as 3D-LCMV, 3D-ACR, 3D-JDL, and 3D projection-based reduced dimensional STAP methods, are discussed. Simulation results show that the proposed methods can improve the small-sample support performance of range-dependent clutter suppression in bistatic side-looking MIMO radar. Finally, the results are summarized and the prospects of bistatic MIMO-STAP are discussed.