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类噪声环境下基于滑动相干谱的强迫振荡检测方法研究 被引量:3
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作者 蔡国伟 王丽馨 杨德友 《电工电能新技术》 CSCD 北大核心 2017年第1期59-65,共7页
电力系统中时刻存在负荷投切等环境激励,使得系统响应表现为类似噪声的小幅波动。如果强迫功率振荡的幅值较小,很容易淹没在类噪声信号中。本文推导了类噪声环境下电力系统强迫功率振荡解析表达式,从数学角度阐释了类噪声环境下强迫振... 电力系统中时刻存在负荷投切等环境激励,使得系统响应表现为类似噪声的小幅波动。如果强迫功率振荡的幅值较小,很容易淹没在类噪声信号中。本文推导了类噪声环境下电力系统强迫功率振荡解析表达式,从数学角度阐释了类噪声环境下强迫振荡的机理特性。在深入分析类噪声环境下小幅强迫振荡频谱特征的基础上,提出了基于滑动相干谱法(SCM)的小幅强迫功率振荡检测方法。首先采集得到两组发电机有功功率类噪声响应数据,计算得到对应的自功率谱密度和互功率谱密度,从而计算得到两组数据的幅值平方相干函数值,进而通过对所得幅值平方相干函数值的量化比较,检测出淹没在类噪声信号中的小幅强迫功率振荡。IEEE 4机2区域系统和16机68节点系统验证了所提检测方法的可行性及有效性。 展开更多
关键词 类噪声环境 低频振荡 强迫功率振荡 滑动相干谱法
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Improved speech absence probability estimation based on environmental noise classification 被引量:2
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作者 SON Young-ho LEE Sang-min 《Journal of Central South University》 SCIE EI CAS 2012年第9期2548-2553,共6页
An improved speech absence probability estimation was proposed using environmental noise classification for speech enhancement.A relevant noise estimation approach,known as the speech presence uncertainty tracking met... An improved speech absence probability estimation was proposed using environmental noise classification for speech enhancement.A relevant noise estimation approach,known as the speech presence uncertainty tracking method,requires seeking the "a priori" probability of speech absence that is derived by applying microphone input signal and the noise signal based on the estimated value of the "a posteriori" signal-to-noise ratio(SNR).To overcome this problem,first,the optimal values in terms of the perceived speech quality of a variety of noise types are derived.Second,the estimated optimal values are assigned according to the determined noise type which is classified by a real-time noise classification algorithm based on the Gaussian mixture model(GMM).The proposed algorithm estimates the speech absence probability using a noise classification algorithm which is based on GMM to apply the optimal parameter of each noise type,unlike the conventional approach which uses a fixed threshold and smoothing parameter.The performance of the proposed method was evaluated by objective tests,such as the perceptual evaluation of speech quality(PESQ) and composite measure.Performance was then evaluated by a subjective test,namely,mean opinion scores(MOS) under various noise environments.The proposed method show better results than existing methods. 展开更多
关键词 speech enhancement soft decision speech absence probability Gaussian mixture model (GMM)
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A Fourier spectrum-based strain energy damage detection method for beam-like structures in noisy conditions 被引量:1
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作者 YANG ZhiBo CHEN XueFeng +2 位作者 RADZIENSKI Maciej KUDELA Pawel OSTACHOWICZ Wieslaw 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2017年第8期1188-1196,共9页
In this paper,the Fourier spectrum-based strain energy damage detection method for beam-like structures is proposed based on the discrete Fourier transform.The classical strain energy damage detection method localizes... In this paper,the Fourier spectrum-based strain energy damage detection method for beam-like structures is proposed based on the discrete Fourier transform.The classical strain energy damage detection method localizes damage by the comparison of the strain energy between the intact and inspected structures.The evaluation of the 2nd-order derivative term in the strain energy plays a crucial part in the comparison.The classical methods are mostly based on a numerical derivative estimation for this term.The numerical derivative,however,introduces additional disturbances into damage indications.To address this problem,a discrete Fourier transform-based strain energy is proposed with the emphasis of enhancing the performance in noisy condition.The validations conducted on the simulated and experimental data show that the developed method is effective enough for composite beam damage detection in noisy environments. 展开更多
关键词 Fourier spectrum strain energy (SE) composite beam noisy condition damage detection mode shape
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