检索结果-南通市图书馆

Acta Mathematica Sinica,English Series 2019年第12期35卷 1891-1905页

作者： Ming Chu GAO School of Mathematics and Information Science Baoji University of Arts and Sciences Department of Mathematics Louisiana College

In this paper,we construct random two-faced families of matrices with non-gaussian entries to approximate a bi-free central limit distribution with a positive definite covariance *** prove that,under modest conditions weaker than independence,a family of random two-faced families of matrices with non-gaussian entries is asymptotically bi-free from a two-faced family of constant diagonal matrices.

关键词： Bi-free central limit distributions non-gaussian random matrices asymptotic bi-freeness

non-gaussian feature of the output field from a double qubit-cavity ultrastrong coupling system

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2024年第7期76卷 30-36页

作者： Sheng-wen Xu Shi-yu Dai Teng Zhao Center for Quantum Science and Technology Jiangxi Normal UniversityNanchang 330022China

We investigate the non-gaussian feature of radiation in a circuit quantum electrodynamics(QED)system where two qubits are strongly coupled to a single-mode *** the regime of ultrastrong coupling(USC),the rotating-wave approximation is not valid,and the Rabi Hamiltonian contains counter-rotating wave terms,leading to level crossing and avoided crossings in the energy *** further analyze the intensity-amplitude correlation of the output field in these two novel *** the USC regime,the creation and annihilation operators in the correlation function are replaced,allowing for the identification of non-gaussian features in the output *** findings reveal that despite the absence of squeezing effects in the output light,significant non-gaussian characteristics are ***,we demonstrate that as the driving or coupling strength increases,the non-gaussian features of the output field become more *** suggests that USC systems hold broad potential applications in the realms of nonlinear optics and the generation of non-gaussian states.

关键词： ultrastrong coupling non-gaussian intensity-amplitude correlation

The Impact of non—gaussian Distribution Traffic on Network Performnce

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2002年第1期17卷 106-111页

作者：金志刚 OliverW.W.Yang 等 DepartmentofComputerScience TianjinUniversityTianjin300072P.R.China SchoolofInformationTechnologyandEngineering UniversityofOttawaOttawaOntarioCanadaK1N6N5

Recent extensive measurements of real-life traffic demonstrate that the probability density function of the traffic in *** a traffic model does not capture this characteristics,any analytical or simulation results will not be *** this work,we study the impact of non-gaussian traffic on network performance,and present an approach that can accurately model the marginal distribution of real-life *** the long-and short-range autocorrelations are also *** show that the removal of non-gaussian components of the process does not change its correlation structure,and we validate our promising procedure by simulations.

关键词： non-gaussian self-similarity performance

Space-time clutter model for airborne bistatic radar with non-gaussian statistics

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2009年第2期20卷 283-290页

作者： Duan Rui Wang Xuegang Jiang Chaoshu Chen Zhuming Dept.of Electronic Engineering Univ. of Electronic Science and Technology of China Chengdu 610054 P. R. China

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 bistatic 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.

关键词： airborne bistatic radar clutter model geometry non-gaussian

Control method for multi-input multi-output non-gaussian random vibration test with cross spectra consideration

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2017年第6期30卷 1895-1906页

作者： Ronghui ZHENG Huaihai CHEN Xudong HE State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

A control method for Multi-Input Multi-Output（MIMO） non-gaussian random vibration test with cross spectra consideration is proposed in the paper. The aim of the proposed control method is to replicate the specified references composed of auto spectral densities, cross spectral densities and kurtoses on the test article in the laboratory. It is found that the cross spectral densities will bring intractable coupling problems and induce difficulty for the control of the multioutput kurtoses. Hence, a sequential phase modification method is put forward to solve the coupling problems in multi-input multi-output non-gaussian random vibration test. To achieve the specified responses, an improved zero memory nonlinear transformation is utilized first to modify the Fourier phases of the signals with sequential phase modification method to obtain one frame reference response signals which satisfy the reference spectra and reference kurtoses. Then, an inverse system method is used in frequency domain to obtain the continuous stationary drive signals. At the same time, the matrix power control algorithm is utilized to control the spectra and kurtoses of the response signals further. At the end of the paper, a simulation example with a cantilever beam and a vibration shaker test are implemented and the results support the proposed method very well.

关键词： Cross spectra Kurtosis control Multi-input multi-output non-gaussian Random vibration test

Wave Period Distributions in non-gaussian Mixed Sea States

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2013年第6期27卷 809-820页

作者：王迎光 Department of Naval Architecture and Ocean Engineering Shanghai Jiao Tong University State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University

The wave period probability densities in non-gaussian mixed sea states are calculated by utilizing a transformed gaussian process method. The transformation relating the non-gaussian process and the original gaussian process is obtained based on the equivalence of the level up-crossing rates of the two processes. A saddle point approximation procedure is applied for calculating the level up-crossing rates in this study. The accuracy and efficiency of the transformed gaussian process method are validated by comparing the results predicted by using the method with those predicted by the Monte Carlo simulation method.

关键词： wave period mixed sea state non-gaussian saddle point approximation Monte Carlo simulation

Generation of non-gaussian Random Vibration Excitation Signal for Reliability Enhancement Test

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2007年第3期20卷 236-239页

作者： YU Ying-yang JIANG Tong-min Department of System Engineering of Engineering Technolog） Beijing University of Aeronautics and Astronautics Beijing 100083 China

During environment testing, the time histories of some dynamic environments follow non-gaussian distribution. It is always assumed that the random vibration simulated follows gaussian distribution, because the traditional digital random vibration control system can only supply the random vibration excitation signal of gaussian. Yo simulate the real environment of product, a method is developed in this paper that can generate non-gaussian random signal with specified power spectrum density （PSD）, skewness and kurtosis by shot noise. In this way, non-gaussian random vibration can be produced on traditional electrodynamic shaker. It solves the problems of spectral valley and energy shortage in low frequency on omni-axis shaker. At last, the wavelet is used to analyze the non-gaussian signal

关键词： non-gaussian shot noise skewness kurtosis wavelet

Performance Analysis of Outage Probability and Error Rate of Square M-QAM in Mobile Wireless Communication Systems over Generalized α-μ Fading Channels with non-gaussian Noise

在线全文

学校读者我要写书评

暂无评论

China Communications 2018年第1期15卷 62-71页

作者： Fares S. Aimehmadi Osamah S. Badarneh University of Tabuk Electrical Engineering Department Tabuk 71491 Saudi Arabia

This paper derives new and exact closed-form expressions for the average symbol error rate(SER) of square M-ary quadrature amplitude modulation(M-QAM) in wireless communication systems over theα-μfading channels subject to an additive non-gaussian noise. The obtained expressions take into account static and mobile wireless receivers. In addition, a closed-form expression for the outage probability in mobile networks is obtained. Please note that all derived expressions in this paper a valid for integer and non-integer values of the fading parameters. Analytical results are presented to study the impact of noise shaping parameter, severity of fading, and mobility on the average SER. Monte-Carlo simulations results are also provided to validate the accuracy of the analytical results.

关键词： α-μ fading symbol error rate non-gaussian noise random waypoint mobili-ty model

Effect of non-gaussian properties of the sea surface on the low-incidence radar backscatter and its inversion in terms of wave spectra by an ocean wave spectrometer

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Oceanology and Limnology 2015年第5期33卷 1142-1156页

作者：陈萍尹巧华黄萍 Science and Technology on Multi-spectral Information Processing Laboratory School of Electronic Information and Communications Huazhong University of Science and Technology

The principle of ocean wave spectrometers was first presented several decades ago to detect the directional wave spectrum with real-aperture radar(Jackson,1981). To invert wave spectra using an ocean wave spectrometer,for simplicity,the hydrodynamic forcing and wave-wave interaction effect are neglected and a gaussian slope probability density function(pdf) is used to calculate the normalized backscattering cross-section( σ 0) of the ocean surface. However,the real sea surface is non-gaussian. It is not known whether the non-gaussian property of the sea surface will affect the performance of the inversion of the wave spectrum if following existing inversion steps and methods. In this paper,the pdf of the sea surface slope is expressed as a Gram-Charlier fourth-order expansion,which is quasi-gaussian. The modulation transfer function(MTF) is derived for a non-gaussian slope pdf. The effects of non-gaussian properties of the sea surface slope on the inversion process and result are then studied in a simulation of the SWIM(Surface Waves Investigation and Monitoring) instrument configuration to be used on the CFOSAT(China-France Oceanography Satellite) mission. The simulation results show that the mean trend of σ 0 depends on the sea slope pdf,and the peakedness and skewness coefficients of the slope pdf affect the shape of the mean trend of σ 0 versus incidence and azimuth; owing to high resolution of σ 0 in the range direction,MTF obtained using the mean trend of σ 0 is almost as accurate as that set in the direct simulation; in the inversion,if ignoring the non-gaussian assumption,the inversion performances for the wave spectrum decrease,as seen for an increase in the energy error of the inverted wave slope spectrum. However,the peak wavelength and wave direction are the same for inversions that consider and ignore the non-gaussian property.

关键词： slope probability density of the sea surface ocean wave spectrometer non-gaussian directionalwave spectrum energy error

Estimation Performance for the Cubature Particle Filter under nonlinear/non-gaussian Environments

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2021年第5期67卷 1555-1575页

作者： Dah-Jing Jwo Chien-Hao Tseng Department of Communications Navigation and Control EngineeringTaiwan Ocean UniversityKeelung202301TaiwanChina National Center for High-Performance Computing National Applied Research LaboratoriesHsinchu30076TaiwanChina

This paper evaluates the state estimation performance for processing nonlinear/non-gaussian systems using the cubature particle lter(CPF),which is an estimation algorithm that combines the cubature Kalman lter(CKF)and the particle lter(PF).The CPF is essentially a realization of PF where the third-degree cubature rule based on numerical integration method is adopted to approximate the proposal *** is benecial where the CKF is used to generate the importance density function in the PF framework for effectively resolving the nonlinear/non-gaussian *** on the spherical-radial transformation to generate an even number of equally weighted cubature points,the CKF uses cubature points with the same weights through the spherical-radial integration rule and employs an analytical probability density function(pdf)to capture the mean and covariance of the posterior distribution using the total probability theorem and subsequently uses the measurement to update with Bayes’*** is capable of acquiring a maximum a posteriori probability estimate of the nonlinear system,and thus the importance density function can be used to approximate the true posterior density *** Bayesian ltering,the nonlinear lter performs well when all conditional densities are assumed *** applied to the nonlinear/non-gaussian distribution systems,the CPF algorithm can remarkably improve the estimation accuracy as compared to the other particle lterbased approaches,such as the extended particle lter(EPF),and unscented particle lter(UPF),and also the Kalman lter(KF)-type approaches,such as the extended Kalman lter(EKF),unscented Kalman lter(UKF)and *** illustrative examples are presented showing that the CPF achieves better performance as compared to the other approaches.

关键词： nonlinear estimation non-gaussian Kalman lter unscented Kalman lter cubature particle filter