检索结果-内蒙古大学图书馆

Novelty method for the utility harmonic impedance estimation based on Gaussian mixed model

IET GENERATION TRANSMISSION & DISTRIBUTION 2020年第13期14卷 2573-2580页

作者： Tang, Zhirong Shu, Qin Xu, Fangwei Jiang, Yue Chengdu Univ Technol Coll Nucl Technol & Automat Engn Chengdu 610059 Peoples R China Sichuan Univ Coll Elect Engn Chengdu 610065 Peoples R China

The accurate estimation of harmonic impedance on the utility side of a point of common coupling (PCC) is much important to harmonic control, harmonic emission level, and harmonic responsibility analysis. In this study, a novel estimation method for the utility harmonic impedance is proposed, which employs the Gaussian mixed model (GMM) to fit the measured data at a PCC, because the authors find that the statistical distribution of the measured data at a PCC is close to the Gaussian distribution. Also, in theory, GMM can approach the probability distribution of any data. In this method, the Norton equivalent circuit model at a PCC is first expressed as a GMM, and the utility harmonic impedance in the GMM is estimated by expectation maximisation iterative method. Compared to the existing estimation methods, an outstanding advantage of this method is that it is less affected by background harmonics;therefore, higher accuracy can be acquired in this method. The effectiveness and accuracy of this method are verified by simulation experiments and field data.

关键词： expectation-maximisation algorithm Gaussian processes equivalent circuits harmonic analysis iterative methods electric impedance Gaussian distribution power system harmonics statistical distributions parameter estimation probability novelty method utility harmonic impedance estimation Gaussian mixed model PCC harmonic control harmonic emission level harmonic responsibility analysis novel estimation method GMM Gaussian distribution Norton equivalent circuit model expectation maximisation iterative method existing estimation methods background harmonics

来源：评论

学校读者我要写书评

暂无评论

ONLINE ESTIMATION OF DYNAMIC SHOCK-ERROR MODELS BASED ON THE KULLBACK-LEIBLER INFORMATION MEASURE

引用

IEEE TRANSACTIONS ON AUTOMATIC CONTROL 1994年第5期39卷 1129-1135页

作者： KRISHNAMURTHY, V Cooperative Res. Center for Robust & Adaptive Syst. Australian Nat. Univ. Canberra ACT Australia

In this paper we develop two sequential or ''on-line'' estimation schemes in the time domain for dynamic shock-error models which are special cases of errors-in-variables models. Our approach utilizes a state-space representation of the model, Kalman filtering techniques, and on-line algorithms. The first on-line algorithm is based on the expectation-maximization algorithm and uses a recursive Gauss-Newton scheme to maximize the Kullback Leibler information measure. The second on-line algorithm we propose is a gradient-based scheme and uses stochastic approximations to maximize the log likelihood. In comparison to the off-line Maximum Likelihood estimation scheme used in [1], our on-line algorithms have significantly reduced computational costs and negligible memory requirements. Simulations illustrate the satisfactory performance of the algorithms in estimating errors-in-variables systems with parameters that vary slowly with time or undergo infrequent jump changes.

关键词： error model Scheme State-space Representation variable system TIME-DOMAIN expectation-maximisation algorithm algorithms Writers IN-LINE

来源：评论

学校读者我要写书评

暂无评论

Radar coincidence imaging by exploiting the continuity of extended target

引用

IET RADAR SONAR AND NAVIGATION 2017年第1期11卷 60-69页

作者： Zhou, Xiaoli Wang, Hongqiang Cheng, Yongqiang Qin, Yuliang Natl Univ Def Technol Sch Elect Sci & Engn Changsha 410073 Peoples R China

Radar coincidence imaging (RCI) is a recently developed concept of radar imaging, which introduces the optical coincidence imaging to traditional microwave imaging. Conventional RCI methods ignore the structure information of complex extended target, which limits its applications in high resolution imaging, thus an adaptive clustered sparse Bayesian learning algorithm is proposed in this study. To exploit the continuity of extended target, a hierarchical correlated Gaussian prior model is introduced to take into account both the sparse prior and the cluster prior, and then the algorithm alternates between steps of target reconstruction and parameter optimisation under the variational Bayesian expectation-maximisation framework. Therefore, the reconstruction of each coefficient involves its immediate neighbours, and the parameter indicating the pattern relevance among neighbouring scatterers is updated adaptively during the iterations. Experimental results demonstrate that the proposed algorithm could realise high resolution imaging effectively for extended target.

关键词： radar imaging radar tracking target tracking learning (artificial intelligence) Gaussian processes expectation-maximisation algorithm radar coincidence imaging extended target continuity RCI optical coincidence imaging microwave imaging structure information complex extended target high resolution imaging adaptive clustered sparse Bayesian learning algorithm correlated Gaussian prior model parameter optimisation target reconstruction variational Bayesian expectation-maximisation framework

来源：评论

学校读者我要写书评

暂无评论

Low-complexity joint data detection and channel equalisation for highly mobile orthogonal frequency division multiplexing systems

引用

IET COMMUNICATIONS 2010年第8期4卷 1000-1011页

作者： Dogan, H. Panayirci, E. Poor, H. Vincent Istanbul Univ Dept Elect & Elect Engn TR-34320 Istanbul Turkey Princeton Univ Dept Elect Engn Princeton NJ 08544 USA

This study is concerned with the challenging and timely problem of channel equalisation and data detection for orthogonal frequency division multiplexing (OFDM) systems in the presence of frequency-selective and very rapidly time-varying channels. The algorithm is based on the space alternating generalised expectation-maximisation (SAGE) technique which is particularly well suited to multicarrier signal formats and can be easily extended to multi-input multi-output-OFDM systems. In fast fading channels, the orthogonality between subcarriers is destroyed by the time variation of a fading channel over an OFDM symbol duration which causes severe inter-carrier interference (ICI) and, in conventional frequency-domain approaches, results in an irreducible error floor. The proposed joint data detection and equalisation algorithm updates the data sequences in series leading to a receiver structure that also incorporates ICI cancellation, enabling the system to operate at high vehicle speeds. A computational complexity investigation as well as detailed computer simulations indicate that this algorithm has significant performance and complexity advantages over existing suboptimal detection and equalisation algorithms proposed earlier in the literature.

关键词： Electromagnetic compatibility and interference expectation-maximisation algorithm channel equalisation frequency selective channels fading channels Modulation and coding methods Mobile radio systems ICI cancellation Other topics in statistics OFDM modulation time-varying channels channel estimation space alternating generalised expectation-maximisation technique low complexity joint data detection highly mobile orthogonal frequency division multiplexing systems mobile radio intercarrier interference Communication channel equalisation and identification multicarrier signal suboptimal detection multiinput multioutput OFDM systems MIMO communication interference suppression

来源：评论

学校读者我要写书评

暂无评论

Cardinalised probability hypothesis density tracking algorithm for extended objects with glint noise

引用

IET SCIENCE MEASUREMENT & TECHNOLOGY 2016年第5期10卷 528-536页

作者： Li, Cuiyun Wang, Rong Hu, Yuhen Wang, Jinbin Xidian Univ Sch Elect Engn Xian 710071 Peoples R China Shangluo Univ Sch Elect Informat & Elect Engn Shang Luo 726000 Peoples R China Univ Wisconsin Dept Elect & Comp Engn 1415 Johnson Dr Madison WI 53706 USA

The authors present a novel cardinalised probability hypothesis density (CPHD) algorithm under the assumption of a glint measurement noise model with unknown inverse covariance. Noise parameters are assumed to have a Gamma prior distribution so that the predicted and updated PHDs can have mixture of Gaussians representations. A variational Bayesian expectation maximisation procedure is applied to iteratively estimate parameters of the mixture distributions through random hypersurface model CPHD prediction and update steps. Simulation results show that the proposed algorithm can adaptively track extended objects with unknown object number and glint measurement noise, while achieving higher precision compared against the traditional approach.

关键词： object tracking measurement errors measurement uncertainty covariance analysis Gaussian processes Bayes methods expectation-maximisation algorithm parameter estimation cardinalised probability hypothesis density tracking algorithm extended objects glint measurement noise model unknown inverse covariance noise parameters gamma prior distribution Gaussians representations variational Bayesian expectation maximisation procedure iterative parameter estimate

来源：评论

学校读者我要写书评

暂无评论

Direct speech feature estimation using an iterative EM algorithm for vocal fold pathology detection

引用

IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING 1996年第4期43卷 373-383页

作者： GavidiaCeballos, L Hansen, JHL DUKE UNIV ROBUST SPEECH PROC LABDEPT ELECT ENGNDURHAMNC 27708 DUKE UNIV ROBUST SPEECH PROC LABDEPT BIOMED ENGNDURHAMNC 27708

The focus of this study is to formulate a speech parameter estimation algorithm for analysis/detection of vocal fold pathology, The speech processing algorithm proposed estimates features necessary to formulate a stochastic model to characterize healthy and pathology conditions from speech recordings, The general idea is to separate speech components under healthy and assumed pathology conditions, This problem is addressed using an iterative maximum-likelihood (ML) estimation procedure, based on the estimation-maximization (EM) algorithm, A new feature for characterizing pathology, termed enhanced-spectral-pathology component (ESPC), is estimated and shown to vary consistently between healthy and pathology conditions, It is also shown that the mean-area-peak-value (MAPV) and the weighted-slope (WSLOPE) indexes, which are obtained from the ESPC estimate, are meaningful measures of speech pathology conditions, For classification purposes, a five-state hidden-Markov-model (HMM) recognizer was formulated, based on the MAPV, WSLOPE, and ESPC spectral features. A set of log Mel-frequency filter bank coefficients were used to parameterize the ESPC feature, An evaluation of the HMM-based classifier was performed using speech recordings from healthy and vocal fold cancer patients of sustained vowel sounds, It is shown that while both MAPV and WSLOPE are useful features for vocal fold pathology detection, superior performance was achieved using a finer spectral representation of ESPC (e,g,, a detection rate of 88.7% for pathology and 92.8% for healthy condition), One main advantage of the proposed method is that it does not require direct estimation of the glottal flow waveform, Therefore, the limitation of the inability to characterize vocal fold pathology, due to incomplete glottal closure, is no longer an issue, The results suggest that general analysis of the ESPC feature can provide a quantitative, noninvasive approach for analysis, detection, and characterization of spe

关键词： detection rate (DR) expectation-maximisation algorithm Speech Vocal Cords Speech Pathology pathology

来源：评论

学校读者我要写书评

暂无评论

The EM imaging reconstruction method in γ-ray astronomy

引用

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS 1998年第3期145卷 469-481页

作者： Rosello, FJB Martinez, FS Velasco, VR Univ Valencia CSIC Inst Fis Corpuscular E-46100 Valencia Spain Univ Valencia Dept Astron & Astrophys E-46100 Valencia Spain

The simpler imaging reconstruction methods used for gamma-ray coded mask telescopes are based on correlation methods, very fast and simple-to-use but with limitations in the reconstructed image. To improve these results, other reconstruction methods have been developed, such as the maximum entropy methods or the Iterative Removal Of Sources (IROS). However, such kind of methods are slower and can be impracticable for very complex telescopes. In this paper we present an alternative image reconstruction method, based on an iterative maximum likelihood algorithm called the EM algorithm, easy to implement and that can be successfully used for not very complex coded mask systems, as is the case of the LEGRI telescope. This is the first time this algorithm has been applied in gamma-ray astronomy. (C) 1998 Elsevier Science B.V. All rights reserved.

关键词： correlation methods GAMMA RAY ASTRONOMY image reconstruction MAXIMUM ENTROPY METHODS expectation-maximisation algorithm Masks Telescopes Gamma Rays Reconstruction algorithm

来源：评论

学校读者我要写书评

暂无评论

An expert system for predicting nonlinear aeroelastic behavior of an airfoil

引用

JOURNAL OF SOUND AND VIBRATION 2009年第3-5期319卷 1312-1329页

作者： Popescu, C. A. Wong, Y. S. Lee, B. H. K. Grant MacEwan Coll Dept Math & Stat Edmonton AB T5J 4S2 Canada Univ Alberta Dept Math & Stat Sci Edmonton AB T6G 2G1 Canada Inst Aerosp Res Ottawa ON K1A 0R6 Canada

In this paper we present an expert system to perform steady-state response predictions. We consider an aeroelastic model simulating a two degree-of-freedom airfoil oscillating in pitch and plunge with a freeplay nonlinearity in the pitch degree-of-freedom. In the proposed data-driven methodology, a freeplay is first confirmed, and then the locations of the switching points are determined. A state-space formulation is constructed to model the piece-wise linear system. The parameters of the system are estimated using the Kalman filter and the expectation maximization algorithm. The attractive feature of the present approach is its ability to accurately predict the steady-state behavior of the nonlinear aeroelastic system with freeplay, using only a limited amount of transient input data. To demonstrate the effectiveness of the proposed methodology, we present applications to freeplay aeroelastic data arising from wind tunnel experiments and numerical simulations. (C) 2008 Elsevier Ltd. All rights reserved.

关键词： EM algorithm expectation-maximisation algorithm Airfoils Aeroelastics Expert System plunge pitch Kalman filters nonlinearity

来源：评论

学校读者我要写书评

暂无评论

Joint phase noise estimation and data detection in coded multi-input-multi-output systems

引用

IET COMMUNICATIONS 2014年第7期8卷 981-989页

作者： Isikman, Arif O. Mehrpouyan, Hani Nasir, Ali A. Amat, Alexandre G. Kennedy, Rodney. A. Chalmers Univ Technol Commun Syst Grp S-41296 Gothenburg Sweden Calif State Univ Dept Elect & Comp Engn Bakersfield CA USA Australian Natl Univ Res Sch Engn Canberra ACT Australia

The problem of joint oscillator phase noise (PHN) estimation and data detection for multi-input multi-output (MIMO) systems using bit-interleaved-coded modulation is analysed. A new MIMO receiver that iterates between the estimator and the detector, based on the expectation-maximisation (EM) framework, is proposed. It is shown that at high signal-to-noise ratios, a maximum a posteriori (MAP) estimator can be used to carry out the maximisation step of the EM algorithm. Moreover, to reduce the computational complexity of the proposed EM algorithm, a soft decision-directed extended Kalman filter-smoother (EKFS) is applied instead of the MAP estimator to track the PHN parameters. The numerical results show that by combining the proposed EKFS-based approach with an iterative detector that employs low-density parity check codes, PHN can be accurately tracked. The simulations also demonstrate that compared to the existing algorithms, the proposed iterative receiver can significantly enhance the performance of MIMO systems in the presence of PHN.

关键词： phase noise MIMO communication radio receivers interleaved codes oscillators expectation-maximisation algorithm maximum likelihood estimation Kalman filters parity check codes iterative methods data detection coded multi-input-multi-output system joint oscillator phase noise estimation PHN estimation MIMO receiver bit-interleaved-coded modulation expectation-maximisation EM algorithm signal-to-noise ratio maximum a posteriori MAP estimator soft decision-directed extended Kalman filter-smoother EKFS-based approach low-density parity check code iterative receiver

来源：评论

学校读者我要写书评

暂无评论

Ultra wideband OFDM channel estimation through a wavelet based EM-MAP algorithm

引用

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS 2008年第7期19卷 761-771页

作者： Sadough, S. M. S. Ichir, M. Duhamel, P. Jaffrot, E. ENSTA UEI F-75015 Paris France CNRS Supelec Signaux & Syst Lab F-91190 Gif Sur Yvette France Univ Nacl San Marin Pcia De Buenos Aires Argentina

Ultra wideband (UWB) communications involve very sparse channels, since the bandwidth increase results in a better time resolution. This property is used here to propose an efficient algorithm jointly estimating the channel and the transmitted symbols. More precisely, this paper introduces an expectation-maximisation (EM) algorithm within a wavelet domain Bayesian framework for semi-blind channel estimation of multiband orthogonal frequency-division multiplexing (MB-OFDM) based UWB communications. A prior distribution is chosen for the wavelet coefficients of the unknown channel impulse response (CIR) in order to model a sparseness property of the wavelet representation. This prior yields, in maximum a posteriori (MAP) estimation, a thresholding rule within the EM algorithm. We particularly focus Oil reducing the number of estimated parameters by iteratively discarding 'insignificant' wavelet coefficients from the estimation process. Simulation results using UWB channels issued from both models and measurements show that under sparsity conditions, the proposed algorithm outperforms pilot based channel estimation in terms of mean square error (MSE) and bit error rate (BER). Moreover, the estimation accuracy is improved, while the computational complexity is reduced, when compared to traditional semi-blind methods. Copyright (C) 2008 John Wiley & Sons, Ltd.

关键词： Orthogonal frequency division multiplexing sparse channel wavelets channel estimation expectation-maximisation algorithm Ultra wideband communication Ultra wideband technologies complexity classes Bit error rate Mean square error Wavelet coefficients channel blind estimation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：