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A Bayesian approach to seafloor classification using multi-beam echo-sounder backscatter data 总被引:2,自引:0,他引:2
Dick G. Simons 《Applied Acoustics》2009,70(10):1258-520
Seafloor classification using acoustic remote sensing techniques is an attractive approach due to its high-coverage capabilities and limited costs. The multi-beam echo-sounder (MBES) system provides high-resolution bathymetry and backscatter information with 100% coverage. In this paper, we present a seafloor classification method that employs the MBES backscatter data. The method uses the averaged backscatter data per beam. It, therefore, is independent on the quality of the MBES calibration. Also, its performance is insensitive to seafloor type variation along the MBES swathe and corrections for the angular dependence of the backscatter are not needed. The method accounts for the ping-to-ping variability of the backscatter intensity. It estimates both the number of seafloor types present in the survey area and the probability density function for the backscatter strength at a certain angle for each of the seafloor types. Application of the method to MBES backscatter data acquired in a well-known test area in the North Sea shows very good agreement with available ground truth. The method’s discriminatory performance for this area is demonstrated to be comparable to that of taking samples of the sediment. All seafloor types known to be present in the area are resolved for. Application of the method to the Stanton bank data set shows clearly separable areas that differ in seafloor composition. 相似文献
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I.IntroductionTheprob1cmofsuppressingstrongpointinterferencesourceisavcryimportantthesisinsonardesign.Fortheana1ogsonar,thesolutionofthisprob1emisquitedifficu1t.Untilthedevelopmentofdigitalsonar,thereissomerescarchreportsaboutsuppressingstrongpointin-terferencesource.Theear1ierworkin1969,dedicatcdbyV.C.Anderson,istheconccptofDICANNE(DigitalInterfcrcnceCance1lingAdaptiveNu1lNetworkEquipment)['l.Thisisadoublecompensatormulti-bcamsystcm.Oneisusedtoformintcrfercncebeamandanothcrisusedtofor… 相似文献
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Dong-Xing Cao·Wei Zhang·Ming-Hui Yao College of Mechanical Engineering Beijing University of Technology Beijing China 《Acta Mechanica Sinica》2010,26(6):967-976
This paper focuses on theoretical and experimental investigations of planar nonlinear vibrations and chaotic dynamics of an L-shape beam structure subjected to fundamental harmonic excitation,which is composed of two beams with right-angled L-shape.The ordinary differential governing equation of motion for the L-shape beam structure with two-degree-of-freedom is firstly derived by applying the substructure synthesis method and the Lagrangian equation.Then,the method of multiple scales is utilized to obtain a four-dimensional averaged equation of the L-shape beam structure.Numerical simulations,based on the mathematical model,are presented to analyze the nonlinear responses and chaotic dynamics of the L-shape beam structure.The bifurcation diagram,phase portrait,amplitude spectrum and Poincare map are plotted to illustrate the periodic and chaotic motions of the L-shape beam structure.The existence of the Shilnikov type multi-pulse chaotic motion is also observed from the numerical results.Furthermore, experimental investigations of the L-shape beam structure are performed,and there is a qualitative agreement between the numerical and experimental results.It is also shown that out-of-plane motion may appear intuitively. 相似文献
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张洋 《电子信息对抗技术》2003,18(6):16-17
本文详细介绍了一种新多波束发射机的设计方案,不采用微波大功率单刀双掷开关而采用前后向发射机获得双向发射功能。本文给出这种发射机等效辐射功率的计算公式,并与传统多波束发射机相比较,讨论这种新发射机的优缺点。 相似文献
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高峰值功率速调管因其作为高功率微波源而受到各国的重视。采用单电子注方案的高峰值功率速调管存在许多难以克服的问题,如工作电压很高,输出效率偏低,系统体积偏大等。对高峰值功率多注速调管进行了初步的研究,重点研究了S波段50 MW多注速调管的电子光学系统和高频互作用系统。研究表明,在与单注速调管相同的功率电平下,多注速调管的工作电压明显降低,输出效率明显提高,同时,这种管型也存在结构复杂、电子注聚焦和消除非工作模式困难等技术问题。 相似文献
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Phased Array Feed (PAF) is a small two-dimensional phased array antenna, playing a role as the multi-beam feed for the reflector antenna. The prominent capability of large continuous Field-of-View (FoV) coverage and fast survey speed makes PAF the promising feed for radio telescopes. In this paper, the effect of feed array of PAF on the gain fluctuations over FoV is analyzed on a simplified model of the Five-hundred-meter Spherical Aperture radio Telescope (FAST), including illumination pattern edge taper, element spacing, element arrangement and element amount. And the differences between rectangular and hexagonal array arrangements are compared. The relationship between the FoV and array configuration are concluded at last. 相似文献