检索结果-内蒙古大学图书馆

Research on the intrinsic mode function (IMF) criterion in emd method

MECHANICAL SYSTEMS AND SIGNAL PROCESSING 2006年第4期20卷 817-822页

作者： Cheng, JS Yu, DJ Yang, Y Hunan Univ Coll Mech & Automot Engn Changsha 410082 Peoples R China

Empirical mode decomposition (emd) is a self-adaptive signal-processing method, which has been applied in nonstationary signal-processing successfully. Aiming at the problem of intrinsic mode function (IMF) criterion in the emd method, the energy difference tracking method is proposed in this paper according to the integrity and orthogonality of the IMFs and used to define the IMF in the sifting process. By analyzing the simulated and actual signals, it is confirmed that the IMFs defined by the energy difference tracking method meet the orthogonality condition and reflect the intrinsic and real information of the analysed signal. By comparing the energy difference tracking method with the Cauchy-type convergence criterion, it is demonstrated that the IMFs obtained by the energy difference tracking method can reflect the intrinsic information included in the signal more clearly and their index of orthogonal (IO) is smaller. (c) 2005 Elsevier Ltd. All rights reserved.

关键词： emd method IMF criterion orthogonality energy difference tracking method

来源：评论

学校读者我要写书评

暂无评论

Application of emd method to friction signal processing

引用

MECHANICAL SYSTEMS AND SIGNAL PROCESSING 2008年第1期22卷 248-259页

作者： Guo, Kejian Zhang, Xingang Li, Hongguang Meng, Guang Shanghai Jiao Tong Univ State Key Lab Mech Syst & Vibrat Shanghai 200240 Peoples R China

Due to measurement limitation, the measured friction signal often contains noise and other force components such as elastic forces. Traditional Fourier-based analysis methods are not suitable to process nonlinear and non-stationary signal. In this paper, the combination of median filter and empirical mode decomposition (emd) method is used to analyze the measured friction signal. Median filter is a nonlinear process useful in reducing random noise, while emd method has offered a powerful method for nonlinear and non-stationary data processing. The background noise and the noise arising from the measurement system in the measured friction signal are removed using median filter first. Then the other force components except the real friction force can be extracted from the measured friction signal using the emd method. The residue after extracting can be taken as a relatively clean and real friction force. This method is compared with the traditional Fourier-based methods and wavelet decomposition method. The comparison results both in time domain and in Hilbert spectrum can show the superiority of the emd method in dealing with the problem of friction signal processing. (c) 2007 Elsevier Ltd. All rights reserved.

关键词： emd method median filter nonlinear and non-stationary traditional Fourier-based analysis wavelet decomposition Hilbert spectrum

来源：评论

学校读者我要写书评

暂无评论

A fault diagnosis approach for roller bearings based on emd method and AR model

引用

MECHANICAL SYSTEMS AND SIGNAL PROCESSING 2006年第2期20卷 350-362页

作者： Cheng, JS Yu, DJ Yang, Y Hunan Univ Coll Mech & Automot Engn Changsha 410082 Peoples R China

The main purpose of this paper is to propose a new fault feature extraction approach based on empirical mode decomposition (emd) method and autoregressive (AR) model for roller bearings. AR model is an effective approach to extract the fault feature of the vibration signals and the fault pattern can be identified directly by the extracted fault features without establishing the mathematical model and studying the fault mechanism of the system. However, AR model can only be applied to stationary signals, while the fault vibration signals of a roller bearing are non-stationary. Aiming at this problem, in this paper, the emd method is used as a pretreatment to decompose the non-stationary vibration signal of a roller bearing into a number of intrinsic mode function (IMF) components which are stationary, then the AR model of each IMF component can be established. The AR parameters and the remnant's variance of the AR models of each IMF components are regarded as the feature vectors. The Mahalanobis distance criterion function is used to identify the condition and fault pattern of a roller bearing. Experimental analysis results show that the roller bearing fault features can be extracted by the proposed approach effectively. (c) 2004 Elsevier Ltd. All rights reserved.

关键词： emd method AR model roller bearings fault diagnosis distance criterion function

来源：评论

学校读者我要写书评

暂无评论

Improving the measurement accuracy of an absolute imaging position encoder via a new edge detection method

引用

IET SCIENCE MEASUREMENT & TECHNOLOGY 2017年第4期11卷 406-413页

作者： Cai, Nian Xiao, Pan Ye, Qian Wang, Han Chen, Xindu Ling, Bingo Wing-Kuen Guangdong Univ Technol Sch Informat Engn Guangzhou 510006 Guangdong Peoples R China Guangdong Univ Technol Sch Electromech Engn Guangzhou 510006 Guangdong Peoples R China

To improve the measurement accuracy of an absolute imaging position encoder, a novel edge detection method is developed to accurately detect the edges of grating lines based on empirical mode decomposition (emd). First, according to the characteristics of the absolute position coding image (APCI), the vertical projection of the grey-level APCI is achieved by conventional grey-level transformation. Then, the vertical projection contour is decomposed by an emd method and a finite number of intrinsic mode functions (IMFs) are achieved. Next, the last two IMFs are used to describe the trend of the projection contour. The trend is used as adaptive thresholds to divide the vertical projection contour into different intervals. Finally, the second derivate of the vertical projection contour is applied to obtain the accurate edges in each interval. Experimental results indicate that the proposed method is more robust to heavy noise, bad illumination and a slope compared with the existing methods with respect to edge detection. Also, the proposed method achieves better measurement accuracy than the existing methods.

关键词： computerised instrumentation image colour analysis decomposition diffraction gratings position measurement image coding edge detection measurement accuracy edge detection method grating line empirical mode decomposition absolute position coding image grey-level APCI transformation vertical projection contour decomposition emd method intrinsic mode function IMF

来源：评论

学校读者我要写书评

暂无评论

Scale analysis of pre- and post-midnight ESF bubbles at storm time and quiet time

引用

ADVANCES IN SPACE RESEARCH 2008年第7期42卷 1202-1212页

作者： Chen, K. Y. Su, S. Y. Yeh, H. C. Liu, C. H. Huafan Univ Dept Elect Engn Taipei Hsien Taiwan Natl Cent Univ Inst Space Sci Chungli 32054 Taiwan Acad Sinica Taipei 115 Taiwan

This paper adopts a scale analysis technique to investigate the properties of intermediate-scale plasma structures observed by ROC-SAT-I in the equatorial F-region. A procedure of scale analysis that is developed via the empirical mode decomposition (emd) method of Hilbert-Huang transform (HHT) technique allows the mutually correlated components in velocity, density and relative density gradient to be identified and extracted. Comparing the three parameters, good match in wave form is found for density and velocity in the scales between kilometers and hundred meters (few kilometers to 300 m). It implies that there are electric fields proportional to density fluctuation -delta n/n in the form similar to what is expected for the generalized Rayleigh-Taylor instability. We find that such a one-to-one match holds for various pre- and post-midnight ESF bubbles during quiet and storm times. It, therefore, means that spatial structures of electric field in the intermediate-scale (300 m to few kilometers) correlates to the density structures in a manner of delta E proportional to -delta n/n that is not necessarily depending on the driving mechanism of ESF bubbles, although it is known that ESF bubbles can be driven by different mechanisms under different space weather conditions. In smaller scales (300-50 m), fluctuation patterns of density and velocity do not correlate to each other any more, the good match is then found in the density gradient del(x)n/n and velocity. It is known as the manifestation of the Boltzmann relation. We note that the GRT instability related relationship delta V(z) proportional to delta n/n for irregularities in scale of kilometers holds only for ESF bubbles that occur within +/-5 dip latitude, while the Boltzmann relation (delta V(z) proportional to del(x)n/n) holds for small-scale irregularities without such a limitation. (C) 2007 COSPAR. Published by Elsevier Ltd. All rights reserved.

关键词： ESF irregularity Hilbert-Huang transform emd method scale analysis

来源：评论

学校读者我要写书评

暂无评论

Realising the decomposition of a multi-frequency signal under the coloured noise background by the adaptive stochastic resonance in the non-linear system with periodic potential

引用

IET SIGNAL PROCESSING 2018年第7期12卷 930-936页

作者： Huang, Xiaogang Zhang, Jingling Lv, Meilei Shen, Gang Yang, Jianhua Shanghai Maritime Univ Dept Elect Automat Shanghai 201306 Peoples R China Quzhou Univ Coll Elect & Informat Engn Quzhou 324000 Peoples R China China Univ Min & Technol Sch Mechatron Engn Xuzhou 221116 Jiangsu Peoples R China Univ Michigan Dept Mech Engn Ann Arbor MI 48109 USA

The authors investigate a multi-frequency signal which is decomposed failure by the traditional empirical mode decomposition (emd) method. Moreover, the multi-frequency signal submerged in the coloured noise increases the difficulty in signal decomposition. As a result, this noisy signal is decomposed unsuccessfully by the cooperation of the adaptive stochastic resonance (SR) in the classic bistable system and emd. Then, a method combined adaptive SR in the periodic potential system and emd is put forward to realise the decomposition. Meanwhile, the random particle swarm optimisation algorithm is applied to reach the optimal situation when signal-to-noise ratio attains the maximum value. Different simulation results verify the effectiveness of the proposed method. The proposed method might be useful in dealing with signal processing problems.

关键词： nonlinear systems stochastic processes adaptive signal processing particle swarm optimisation random processes multifrequency signal decomposition coloured noise background adaptive stochastic resonance nonlinear system periodic potential system empirical mode decomposition method emd method classic bistable system random particle swarm optimisation algorithm signal-to-noise ratio signal processing problems

来源：评论

学校读者我要写书评

暂无评论

Internal wave parameter inversion based on Empirical Mode Decomposition

引用

The Journal of China Universities of Posts and Telecommunications 2014年第6期21卷 87-93页

作者： XU Xiao-ge WANG Jing-tao MENG Xiang-hua WEN Xiao-yong School of Information Beijing Wuzi University School of Applied Science Beijing Information Science and Technology University Information Security Center State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications

Wind, the result of earth rotation and other processes,inaugurate the phenomenon of oceanic internal waves（OIWs）, including driving turbulence, affecting nutrient and biomass distribution, and resuspending sediment. Therefore, a good understanding to OIWs＇ characters becomes a vital component to enhance its monitoring and utilization. The parameter inversion was conducted in the article for the OIW based on the empirical mode decomposition（emd） method. The experimental data, the advanced synthetic aperture radar（ASAR） image, was captured in Dongsha Islands surrounding area on July 22, 2011. Considering the formation mechanism of internal waves, two important issues in the emd method-the curve fitting and end effects-were studied. After comparing different algorithms, the cubic spline interpolation（CSI） was used for curve fitting and the boundary full-wave（BFW） method was applied to inhibit the end effects. Used this inversion method, the internal wave signal was extracted from the ASAR image, the distance of the internal wave between peak and trough was calculated, and the half-width of soliton was obtained as well. In addition, the inversion result is consistent with the previous experimental findings, which indicates the effectiveness of our algorithm.

关键词： emd method curve fitting end effects internal wave parameter

来源：评论

学校读者我要写书评

暂无评论

Characterisation of turbulence at sites with coexisting waves and currents: An analysis by empirical mode decomposition

引用

OCEAN ENGINEERING 2024年 313卷

作者： Tan, Tian Venugopal, Vengatesan Univ Edinburgh Inst Energy Syst Sch Engn Kings BldgColin Maclaurin Rd Edinburgh EH9 3DW Scotland

This paper presents a novel side information assisted Empirical Mode Decomposition (emd) method for separating wave orbital velocity from a combined wave-tidal current velocity data, measured by three different Acoustic Doppler Current Profilers (ADCPs) deployed in the Pentland Firth, Orkney Waters, UK. The effectiveness of this technique is confirmed through two methods: (1) the spectra of the wave-removed velocity align with the Kolmogorov -5/3 power law, and (2) the extracted wave orbital velocities were used to derive significant wave heights, which were validated against wave heights measured by the same ADCPs and through numerical modelling carried out with a coupled wave-current tool (TOMAWAC-TELEMAC 3D). The decomposed data was further used to calculate three-dimensional turbulence intensities (TI) for combined wave-current, wave-only, and current-only conditions, across different flow speeds and wave heights. The results demonstrate the robustness of the decomposition method in various scenarios and quantify the individual TI contributions from waves, currents, and their combined effects. This work provides valuable insights into the dynamics of areas where waves and currents coexist.

关键词： Wave-current interactions emd method Tidal energy ADCP measurements Turbulence intensity Wave and current turbulence

来源：评论

学校读者我要写书评

暂无评论

Local rub-impact fault diagnosis of the rotor systems based on emd

引用

MECHANISM AND MACHINE THEORY 2009年第4期44卷 784-791页

作者： Cheng, Junsheng Yu, Dejie Tang, Jiashi Yang, Yu Hunan Univ State Key Lab Adv Design & Mfg Vehicle Body Changsha 410082 Hunan Peoples R China Hunan Univ Coll Mech & Aerosp Changsha 410082 Hunan Peoples R China

Aiming at the characteristics of the vibration signal of a rotor system with local rub-impact fault, a local rub-impact fault diagnosis method of rotor system based on emd (empirical mode decomposition) is proposed in this paper. When the local rub-impact fault occurs in the rotor system, the vibration signals of the rotor system will present amplitude-modulated feature because of the periodic rub-impact between the stator and the rotor. However, it is hard to extract the rub-impact feature for the rub-impact signal is always submerged in the background and noise signals. By using emd, any complicated signal can be decomposed into a finite and often small number of IMFs (intrinsic mode functions), and each IMF may be amplitude-modulated or frequency-modulated signal. Therefore, the rub-impact signal, background signal and noise signal can be separated efficiently and the fault feature of vibration signal of a rotor system with local rub-impact fault can be extracted after the vibration signal of the rotor system is decomposed by emd method. The analysis results from the experimental signal show that the intrinsic mode functions of the vibration signal of a rotor system with local rub-impact fault obviously own the amplitude-modulated characteristics, while those under other work conditions own no distinct amplitude-modulated characteristics. Therefore, the emd method can be applied to the local rub-impact fault diagnosis of the rotor systems efficiently. (C) 2008 Elsevier Ltd. All rights reserved.

关键词： Rotor Local rub-impact fault emd method Fault characteristic

来源：评论

学校读者我要写书评

暂无评论

Multiple scale analysis of complex networks using the empirical mode decomposition method

引用

PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 2008年第12期387卷 2981-2986页

作者： Li, KePing Gao, ZiYou Zhao, XiaoMei Beijing Jiaotong Univ State Key Lab Rail Traff Control & Safety Beijing 100044 Peoples R China

Empirical mode decomposition (emd) method can decompose any complicated data into finite 'intrinsic mode functions' (IMFs). In this paper, we use emd method to analyze and discuss the structural properties of complex networks. A random-walk method is used to collect the data series of network systems. Utilizing the emd method, we decompose the obtained data into finite IMFs under different spatial scales. The analysis results show that emd method is an effective tool for capturing the topological properties of network systems under different spatial scales, such as the modular structures of network systems and their energy densities. (c) 2008 Elsevier B.V. All rights reserved.

关键词： emd method complex network random walk

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：