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A comparative study of optimization algorithms for wavefront shaping 被引量:3
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作者 Zahra Fayyaz Nafiseh Mohammadian +2 位作者 M.Reza Rahimi Tabar Rayyan Manwar Kamran(Mohammad)Avanaki 《Journal of Innovative Optical Health Sciences》 SCIE EI CAS 2019年第4期74-82,共9页
By manipulating the phase map of a wavefront of light using a spatial light modulator,the scattered light can be sharply focused on a specific target.Several iterative optimization algo-rithrns for obtaining the optim... By manipulating the phase map of a wavefront of light using a spatial light modulator,the scattered light can be sharply focused on a specific target.Several iterative optimization algo-rithrns for obtaining the optimumn phase map have been explored.However,there has not been a comparative study on the performance of these algorithms.In this paper,six optimization algorithms for wavefront shaping inchuding continuous sequential,partitioning algorithm,transmission matrix estimation method,particle swarm optimization,genetic algorithm(GA),and simulated annealing(SA)are discussed and compared based on their efficiency when introduced with various measurement noise levels. 展开更多
关键词 wave front shaping algorithms OPTIMIZATION turbid media wavefront shaping
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Bispectrum and asymmetry of wave shape
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作者 Ding Pingxing Kong Yazhen +1 位作者 and Sun Fu (State Key Laboratory Of Estuarine and  ̄al R ̄h, Institute of EStuarine and  ̄al R ̄h, East China NOrmalUniversity. Shanghai 2(XX)62, China Laboratory of Physical  ̄raphy,  ̄n University Of Qngdao,  ̄ac 266003, Chin 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1996年第3期297-305,共9页
on the definition and concept introduced in this paper, the theoretical expareion of surface slope bispectrum for two-dimensional waves is derived. Furthermore,the skewness of surface elevation distribution and that... on the definition and concept introduced in this paper, the theoretical expareion of surface slope bispectrum for two-dimensional waves is derived. Furthermore,the skewness of surface elevation distribution and that of surface slope distribution are respectively employed to define the up-down and front-back asymmetry of a wavee hape so that the relations between bispectrum and skewness are proposed. Through these relations, the updownand front-back asymmetry of the wave shape can be quantitatively determined by means of the bispectral analyses of observed wave data. 展开更多
关键词 Bispecrum wave shape asymmetry NONLINEAR
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NUMERICAL ANALYSIS OF NONLINEAR WAVE FORCE ON LARGE BODY WITH ARBITRARY SHAPE
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作者 Li Jianchu , Fan Jianjun Huang Hening Professor, Dalian Institute of TechnologyPostgraduate, Dalian Institute of TechnologyEngineer, Institute of Marine Environmental Protection State Oceanic Administration 《China Ocean Engineering》 SCIE EI 1989年第2期131-140,共10页
In this paper a nonlinear diffraction theory due to Stoke's 2nd-order wave for computing the wave force on the large body is presented. The radiation condition as r-∞ for 2nd-order scattered potential has been st... In this paper a nonlinear diffraction theory due to Stoke's 2nd-order wave for computing the wave force on the large body is presented. The radiation condition as r-∞ for 2nd-order scattered potential has been studied in connection with asymptotic solutions. A numerical procedure has been developed for the purpose of calculating the nonlinear wave force on the large body with arbitrary shape. 展开更多
关键词 NUMERICAL ANALYSIS OF NONLINEAR wave FORCE ON LARGE BODY WITH ARBITRARY SHAPE BODY BODY
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ROLLING BEARING FAULT DETECTION USING CORRELATION TECHNIQUE
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作者 Xu Yin-ge Yan Yu-ling 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1992年第7期617-622,共6页
It's known that auto-correlation technique is effective in extracting periodical signals from random noises.In the case of fault monitoring of rolling element bearing,we can't acquire the fault information dir... It's known that auto-correlation technique is effective in extracting periodical signals from random noises.In the case of fault monitoring of rolling element bearing,we can't acquire the fault information directly from the original signal because of the difference of signal phases.And the signal is shown as the wide band random signal in auto-correlation function.In this paper,the signal is pre-processed and the results are proved effective.Moreover,by taking the auto-correlation function we can obtain the determined and comparable samples.This is very important for establishing the data base of running condition and for detecting the faults. 展开更多
关键词 auto-correlation function wave shape factor crest factor impulse factor kurtosis factor
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The shape of incident shock wave in steady axisymmetric conical Mach reflection 被引量:3
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作者 Yu-xin Ren Lianhua Tan Zi-niu Wu 《Advances in Aerodynamics》 2020年第1期474-484,共11页
For internal flow with supersonic inflow boundary conditions,a complicated oblique shock reflection may occur.Different from the planar shock reflection problem,where the shape of the incident shock can be a straight ... For internal flow with supersonic inflow boundary conditions,a complicated oblique shock reflection may occur.Different from the planar shock reflection problem,where the shape of the incident shock can be a straight line,the shape of the incident shock wave in the inward-facing axisymmetric shock reflection in steady flow is an unknown curve.In this paper,a simple theoretical approach is proposed to determine the shape of this incident shock wave.The present theory is based on the steady Euler equations.When the assumption that the streamlines are straight lines at locations just behind the incident shock is adopted,an ordinary differential equation can be derived,and the shape of the incident shock wave is given by the solution of this ordinary differential equation.The predicted curves of the incident shock wave at several inlet conditions agree very well with the results of the numerical simulations. 展开更多
关键词 Axisymmetric shock reflection The shape of incident shock wave Euler equations
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A Solver for Helmholtz System Generated by the Discretization of Wave Shape Functions
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作者 Long Yuan Qiya Hu 《Advances in Applied Mathematics and Mechanics》 SCIE 2013年第6期791-808,共18页
An interesting discretization method for Helmholtz equations was introduced in B.Despres[1].This method is based on the ultra weak variational formulation(UWVF)and the wave shape functions,which are exact solutions of... An interesting discretization method for Helmholtz equations was introduced in B.Despres[1].This method is based on the ultra weak variational formulation(UWVF)and the wave shape functions,which are exact solutions of the governing Helmholtz equation.In this paper we are concerned with fast solver for the system generated by the method in[1].We propose a new preconditioner for such system,which can be viewed as a combination between a coarse solver and the block diagonal preconditioner introduced in[13].In our numerical experiments,this preconditioner is applied to solve both two-dimensional and three-dimensional Helmholtz equations,and the numerical results illustrate that the new preconditioner is much more efficient than the original block diagonal preconditioner. 展开更多
关键词 Helmholtz equation ultra weak variational formulation wave shape functions PRECONDITIONER iteration counts
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Scattering of steady cross-plane shear waves by surfaces of arbitrary shape in homogeneous and transversely isotropic media
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作者 WANG Xiaomin LI Mingxuan(Institute of Acoustics, Academia Sinica Beijing 100080) 《Chinese Journal of Acoustics》 1998年第4期307-317,共11页
Two-dimensional scalar equation for the displacement of steady cross-plane shear (SH) waves in homogeneous and transversely isotropic media like unidirectional fibrous com-posites is given. Then, thrbugh a simple coor... Two-dimensional scalar equation for the displacement of steady cross-plane shear (SH) waves in homogeneous and transversely isotropic media like unidirectional fibrous com-posites is given. Then, thrbugh a simple coordinate system transform, the scalar equation is standardized into a Helmholtz equation. Corresponding integral equations are derived for the scattering problems and boundary element method (BEM) is used to calculate the scattered fields of arbitrarily shaped obstacles with both soft and rigid boudary conditions numerically.A discussion is given on the numerical results which is mainly focused on the influence of the a-nisotropy of the media to the directivity of the scattered fields by circular cylindrical voids. 展开更多
关键词 Scattering of steady cross-plane shear waves by surfaces of arbitrary shape in homogeneous and transversely isotropic media
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