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基于信噪比的GNSS随机模型分析 被引量:3
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作者 柴大帅 王胜利 卢秀山 《全球定位系统》 CSCD 2016年第5期42-46,65,共6页
使用差分进行定位时,观测值仍然含有残余的大气延迟以及受到噪声影响。由于信噪比能够很好的反映噪声部分的影响,卫星的高度角与信号传播路径上的大气延迟有很高的相关性,所以利用基于卫星高度角和信噪比的随机模型可以一定程度的削弱... 使用差分进行定位时,观测值仍然含有残余的大气延迟以及受到噪声影响。由于信噪比能够很好的反映噪声部分的影响,卫星的高度角与信号传播路径上的大气延迟有很高的相关性,所以利用基于卫星高度角和信噪比的随机模型可以一定程度的削弱这些误差的影响。本文以实测数据对等权随机模型、高度角随机模型和信噪比随机模型的处理效果进行分析,实验结果证明,信噪比随机模型的处理效果最好,高度角随机模型次之,等权随机模型的处理效果最差。同时本文分析了信噪比对伪距观测值质量的影响,并在此基础上对这三种随机模型进行分析,实验结果显示:在数据预处理时选取合理的信噪比可以使这三种模型的定位精度有所提高。 展开更多
关键词 GNSS 等权随机模型 高度角随机模型 随机模型
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基于小波消噪的EMD模型在GPS振动信号处理中的应用 被引量:4
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作者 李旋 孙磊 +2 位作者 骆辉 戴吾蛟 何伟 《工程勘察》 CSCD 北大核心 2011年第3期72-76,共5页
经验模式分解和小波分解是当前有效处理非平稳信号的两种时频分析方法,它们各具有其优缺点,适用于不同的应用。从对GPS振动信号的预处理、时域和频域处理入手,结果分析表明,对GPS振动信号先进行小波滤波消除随机噪声的干扰,再应用经验... 经验模式分解和小波分解是当前有效处理非平稳信号的两种时频分析方法,它们各具有其优缺点,适用于不同的应用。从对GPS振动信号的预处理、时域和频域处理入手,结果分析表明,对GPS振动信号先进行小波滤波消除随机噪声的干扰,再应用经验模式分解更有利于变形特征信息的分离和提取,提取的信号与振动平台记录数据更加吻合。 展开更多
关键词 经验模式分解(EMD) 小波分解(WD) 全球定位系统 振动变形
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Seismic random noise suppression using an adaptive nonlocal means algorithm 被引量:9
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作者 尚帅 韩立国 +1 位作者 吕庆田 谭尘青 《Applied Geophysics》 SCIE CSCD 2013年第1期33-40,117,118,共10页
Nonlocal means filtering is a noise attenuation method based on redundancies in image information. It is also a nonlocal denoising method that uses the self-similarity of an image, assuming that the valid structures o... Nonlocal means filtering is a noise attenuation method based on redundancies in image information. It is also a nonlocal denoising method that uses the self-similarity of an image, assuming that the valid structures of the image have a certain degree of repeatability that the random noise lacks. In this paper, we use nonlocal means filtering in seismic random noise suppression. To overcome the problems caused by expensive computational costs and improper filter parameters, this paper proposes a block-wise implementation of the nonlocal means method with adaptive filter parameter estimation. Tests with synthetic data and real 2D post-stack seismic data demonstrate that the proposed algorithm better preserves valid seismic information and has a higher accuracy when compared with traditional seismic denoising methods (e.g., f-x deconvolution), which is important for subsequent seismic processing and interpretation. 展开更多
关键词 seismic prospecting ADAPTIVE nonlocal means random noise attenuation
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Random noise attenuation by f–x spatial projection-based complex empirical mode decomposition predictive filtering 被引量:7
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作者 马彦彦 李国发 +2 位作者 王钧 周辉 张保江 《Applied Geophysics》 SCIE CSCD 2015年第1期47-54,121,共9页
The frequency–space(f–x) empirical mode decomposition(EMD) denoising method has two limitations when applied to nonstationary seismic data. First, subtracting the first intrinsic mode function(IMF) results in ... The frequency–space(f–x) empirical mode decomposition(EMD) denoising method has two limitations when applied to nonstationary seismic data. First, subtracting the first intrinsic mode function(IMF) results in signal damage and limited denoising. Second, decomposing the real and imaginary parts of complex data may lead to inconsistent decomposition numbers. Thus, we propose a new method named f–x spatial projection-based complex empirical mode decomposition(CEMD) prediction filtering. The proposed approach directly decomposes complex seismic data into a series of complex IMFs(CIMFs) using the spatial projection-based CEMD algorithm and then applies f–x predictive filtering to the stationary CIMFs to improve the signal-to-noise ratio. Synthetic and real data examples were used to demonstrate the performance of the new method in random noise attenuation and seismic signal preservation. 展开更多
关键词 Complex empirical mode decomposition complex intrinsic mode functions f–x predictive filtering random noise attenuation
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Seismic dip estimation based on the twodimensional Hilbert transform and its application in random noise attenuation 被引量:6
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作者 刘财 陈常乐 +3 位作者 王典 刘洋 王世煜 张亮 《Applied Geophysics》 SCIE CSCD 2015年第1期55-63,121,共10页
In seismic data processing, random noise seriously affects the seismic data quality and subsequently the interpretation. This study aims to increase the signal-to-noise ratio by suppressing random noise and improve th... In seismic data processing, random noise seriously affects the seismic data quality and subsequently the interpretation. This study aims to increase the signal-to-noise ratio by suppressing random noise and improve the accuracy of seismic data interpretation without losing useful information. Hence, we propose a structure-oriented polynomial fitting filter. At the core of structure-oriented filtering is the characterization of the structural trend and the realization of nonstationary filtering. First, we analyze the relation of the frequency response between two-dimensional(2D) derivatives and the 2D Hilbert transform. Then, we derive the noniterative seismic local dip operator using the 2D Hilbert transform to obtain the structural trend. Second, we select polynomial fitting as the nonstationary filtering method and expand the application range of the nonstationary polynomial fitting. Finally, we apply variableamplitude polynomial fitting along the direction of the dip to improve the adaptive structureoriented filtering. Model and field seismic data show that the proposed method suppresses the seismic noise while protecting structural information. 展开更多
关键词 Two-dimensional Hilbert transform random noise attenuation structure protection nonstationary polynomial fitting local seismic d
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An iterative curvelet thresholding algorithm for seismic random noise attenuation 被引量:8
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作者 王德利 仝中飞 +1 位作者 唐晨 朱恒 《Applied Geophysics》 SCIE CSCD 2010年第4期315-324,399,共11页
In this paper,we explore the use of iterative curvelet thresholding for seismic random noise attenuation.A new method for combining the curvelet transform with iterative thresholding to suppress random noise is demons... In this paper,we explore the use of iterative curvelet thresholding for seismic random noise attenuation.A new method for combining the curvelet transform with iterative thresholding to suppress random noise is demonstrated and the issue is described as a linear inverse optimal problem using the L1 norm.Random noise suppression in seismic data is transformed into an L1 norm optimization problem based on the curvelet sparsity transform. Compared to the conventional methods such as median filter algorithm,FX deconvolution, and wavelet thresholding,the results of synthetic and field data processing show that the iterative curvelet thresholding proposed in this paper can sufficiently improve signal to noise radio(SNR) and give higher signal fidelity at the same time.Furthermore,to make better use of the curvelet transform such as multiple scales and multiple directions,we control the curvelet direction of the result after iterative curvelet thresholding to further improve the SNR. 展开更多
关键词 curvelet transform iterative thresholding random noise attenuation
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Seismic data denoising based on mixed time-frequency methods 被引量:3
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作者 蔡涵鹏 贺振华 黄德济 《Applied Geophysics》 SCIE CSCD 2011年第4期319-327,371,共10页
Deconvolution denoising in the f-x domain has some defects when facing situations like complicated geology structure, coherent noise of steep dip angles, and uneven spatial sampling. To solve these problems, a new fil... Deconvolution denoising in the f-x domain has some defects when facing situations like complicated geology structure, coherent noise of steep dip angles, and uneven spatial sampling. To solve these problems, a new filtering method is proposed, which uses the generalized S transform which has good time-frequency concentration criterion to transform seismic data from the time-space to time-frequency-space domain (t-f-x). Then in the t-f-x domain apply Empirical Mode Decomposition (EMD) on each frequency slice and clear the Intrinsic Mode Functions (IMFs) that noise dominates to suppress coherent and random noise. The model study shows that the high frequency component in the first IMF represents mainly noise, so clearing the first IMF can suppress noise. The EMD filtering method in the t-f-x domain after generalized S transform is equivalent to self-adaptive f-k filtering that depends on position, frequency, and truncation characteristics of high wave numbers. This filtering method takes local data time-frequency characteristic into consideration and is easy to perform. Compared with AR predictive filtering, the component that this method filters is highly localized and contains relatively fewer low wave numbers and the filter result does not show over-smoothing effects. Real data processing proves that the EMD filtering method in the t-f-x domain after generalized S transform can effectively suppress random and coherent noise of steep dips. 展开更多
关键词 Empirical Mode Decomposition generalized S transform coherent noise random noise noise suppression
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Seismic data reconstruction based on CS and Fourier theory 被引量:10
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作者 张华 陈小宏 吴信民 《Applied Geophysics》 SCIE CSCD 2013年第2期170-180,236,共12页
Traditional seismic data sampling follows the Nyquist sampling theorem. In this paper, we introduce the theory of compressive sensing (CS), breaking through the limitations of the traditional Nyquist sampling theore... Traditional seismic data sampling follows the Nyquist sampling theorem. In this paper, we introduce the theory of compressive sensing (CS), breaking through the limitations of the traditional Nyquist sampling theorem, rendering the coherent aliases of regular undersampling into harmless incoherent random noise using random undersampling, and effectively turning the reconstruction problem into a much simpler denoising problem. We introduce the projections onto convex sets (POCS) algorithm in the data reconstruction process, apply the exponential decay threshold parameter in the iterations, and modify the traditional reconstruction process that performs forward and reverse transforms in the time and space domain. We propose a new method that uses forward and reverse transforms in the space domain. The proposed method uses less computer memory and improves computational speed. We also analyze the antinoise and anti-aliasing ability of the proposed method, and compare the 2D and 3D data reconstruction. Theoretical models and real data show that the proposed method is effective and of practical importance, as it can reconstruct missing traces and reduce the exploration cost of complex data acquisition. 展开更多
关键词 Fourier transform compressive sensing (CS) projection onto convex sets (POCS) data reconstruction
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偏置信号调制下色关联噪声驱动的线性系统的随机共振 被引量:17
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作者 徐伟 靳艳飞 +1 位作者 徐猛 李伟 《物理学报》 SCIE EI CAS CSCD 北大核心 2005年第11期5027-5033,共7页
研究了偏置信号调制下关联分段噪声驱动的过阻尼线性系统的随机共振现象,推导出了一阶矩、二阶矩和信噪比的解析表达式.通过对信噪比曲线的分析,发现该系统中存在三种不同形式的随机共振:传统的随机共振、真正的随机共振和广义的随机共... 研究了偏置信号调制下关联分段噪声驱动的过阻尼线性系统的随机共振现象,推导出了一阶矩、二阶矩和信噪比的解析表达式.通过对信噪比曲线的分析,发现该系统中存在三种不同形式的随机共振:传统的随机共振、真正的随机共振和广义的随机共振.此外,数值结果还表明,加性噪声能够减弱输出的信噪比,而噪声之间的互相关强度能够使输出的信噪比增强. 展开更多
关键词 随机共振 偏置信号调制的 分段 随机共振 线性系统 声驱动 信号调制 色关联 偏置 解析表达式 共振现象
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基于电子鼻系统的水果腐败过程表征方法 被引量:21
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作者 惠国华 厉鹏 +1 位作者 吴玉玲 朱琳姗 《农业工程学报》 EI CAS CSCD 北大核心 2012年第6期264-268,共5页
为了研究水果腐败过程的新的表征方法,该文采用便携式电子鼻系统试验研究了苹果、梨、桃子、李子、葡萄5种水果的腐败过程,采用非线性随机共振技术提取水果霉变程度特征信息,苹果腐败过程中产生的挥发特征气体量不断上升,而梨、桃子、... 为了研究水果腐败过程的新的表征方法,该文采用便携式电子鼻系统试验研究了苹果、梨、桃子、李子、葡萄5种水果的腐败过程,采用非线性随机共振技术提取水果霉变程度特征信息,苹果腐败过程中产生的挥发特征气体量不断上升,而梨、桃子、李子和葡萄在该过程中挥发气体量先达到最大值后下降,结果表明电子鼻系统可以快速表征水果的腐败过程,这为水果腐败机理研究提供了一种新表征技术手段。 展开更多
关键词 水果 腐烂 电子鼻 随机共振
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Array-enhanced Logical Stochastic Resonance in Coupled Bistable Systems 被引量:1
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作者 吴昊 江慧军 侯中怀 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2012年第1期70-76,I0004,共8页
We investigate the impact of coupling on the reliability of the logic system as well as the logical stochastic resonance (LSR) phenomenon in the coupled logic gates system. It is found that compared with single logi... We investigate the impact of coupling on the reliability of the logic system as well as the logical stochastic resonance (LSR) phenomenon in the coupled logic gates system. It is found that compared with single logic gate, the coupled system could yield reliable logic outputs in a much wider noise region, which means coupling can obviously improve the reliability of the logic system and thus enhance the LSR effect. Moreover, we find that the enhancement is larger for larger system size, whereas for large enough size the enhancement seems to be saturated. Finally, we also examine the effect of coupling strength, it can be observed that the noise region where reliable logic outputs can be obtained evolves non-monotonically as the coupling strength increases, displaying a resonance-like effect. 展开更多
关键词 Logic gate Noise COUPLING Logical stochastic resonance
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Noise-improved information transmission in a nonlinear threshold array for Gaussian mixture noise 被引量:1
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作者 王友国 吴乐南 《Journal of Southeast University(English Edition)》 EI CAS 2006年第1期31-34,共4页
To discuss further the dependence of stochastic resonance on signals, nonlinear systems and noise, especially on noise, the binary input signal buried in Gaussian mixture noise through a nonlinear threshold array is s... To discuss further the dependence of stochastic resonance on signals, nonlinear systems and noise, especially on noise, the binary input signal buried in Gaussian mixture noise through a nonlinear threshold array is studied based on mutual information. It is obtained that Gaussian mixture noise can improve the information transmission through the array. Both stochastic resonance (SR) and suprathreshold stochastic resonance (SSR) can be observed in the single threshold system and in the threshold array. The parameters in noise distribution affect the occurrence of SR and SSR. The efficacy of information transmission can be significantly enhanced as the number of threshold devices in the array increases. These results show further the dependence of SR and SSR on the noise distribution, and also extend the applicability of SR and SSR in information transmission. 展开更多
关键词 stochastic resonance suprathreshold stochastic resonance mutual information Gaussian mixture noise
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Auto-Bcklund transformation and exact solutions of Wick-type stochastic Burgers equation 被引量:1
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作者 陈彬 《Journal of Southeast University(English Edition)》 EI CAS 2005年第4期513-516,共4页
Burgers equation in random environment is studied. In order to give the exact solutions of random Burgers equation, we only consider the Wick-type stochastic Burgers equation which is the perturbation of the Burgers e... Burgers equation in random environment is studied. In order to give the exact solutions of random Burgers equation, we only consider the Wick-type stochastic Burgers equation which is the perturbation of the Burgers equation with variable coefficients by white noise W(t)=Bt, where Bt is a Brown motion. The auto-Baecklund transformation and stochastic soliton solutions of the Wick-type stochastic Burgers equation are shown by the homogeneous balance and Hermite transform. The generalization of the Wick-type stochastic Burgers equation is also studied. 展开更多
关键词 Wick-type stochastic Burgers equation auto-Baecklund transformation stochastic soliton solution white noise Hermite transform homogeneous balance principle
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Improved random noise attenuation using f-x empirical mode decomposition and local similarity 被引量:6
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作者 甘叔玮 王守东 +3 位作者 陈阳康 陈江龙 钟巍 张成林 《Applied Geophysics》 SCIE CSCD 2016年第1期127-134,220,共9页
Conventional f-x empirical mode decomposition(EMD) is an effective random noise attenuation method for use with seismic profiles mainly containing horizontal events.However,when a seismic event is not horizontal,the... Conventional f-x empirical mode decomposition(EMD) is an effective random noise attenuation method for use with seismic profiles mainly containing horizontal events.However,when a seismic event is not horizontal,the use of f-x EMD is harmful to most useful signals.Based on the framework of f-x EMD,this study proposes an improved denoising approach that retrieves lost useful signals by detecting effective signal points in a noise section using local similarity and then designing a weighting operator for retrieving signals.Compared with conventional f-x EMD,f-x predictive filtering,and f-x empirical mode decomposition predictive filtering,the new approach can preserve more useful signals and obtain a relatively cleaner denoised image.Synthetic and field data examples are shown as test performances of the proposed approach,thereby verifying the effectiveness of this method. 展开更多
关键词 Random noise attenuation f-x empirical mode decomposition local similarity dipping event
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oncausal spatial prediction filtering based on an ARMA model 被引量:8
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作者 Liu Zhipeng Chen Xiaohong Li Jingye 《Applied Geophysics》 SCIE CSCD 2009年第2期122-128,共7页
Conventional f-x prediction filtering methods are based on an autoregressive model. The error section is first computed as a source noise but is removed as additive noise to obtain the signal, which results in an assu... Conventional f-x prediction filtering methods are based on an autoregressive model. The error section is first computed as a source noise but is removed as additive noise to obtain the signal, which results in an assumption inconsistency before and after filtering. In this paper, an autoregressive, moving-average model is employed to avoid the model inconsistency. Based on the ARMA model, a noncasual prediction filter is computed and a self-deconvolved projection filter is used for estimating additive noise in order to suppress random noise. The 1-D ARMA model is also extended to the 2-D spatial domain, which is the basis for noncasual spatial prediction filtering for random noise attenuation on 3-D seismic data. Synthetic and field data processing indicate this method can suppress random noise more effectively and preserve the signal simultaneously and does much better than other conventional prediction filtering methods. 展开更多
关键词 AR model ARMA model noncasual random noise self-deconvolved projection filtering
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Random noise suppression for seismic data using a non-local Bayes algorithm 被引量:3
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作者 Chang De-Kuan Yang Wu-Yang +3 位作者 Wang Yi-Hui Yang Qing Wei Xin-Jian and Feng Xiao-Ying 《Applied Geophysics》 SCIE CSCD 2018年第1期91-98,149,共9页
For random noise suppression of seismic data, we present a non-local Bayes (NL- Bayes) filtering algorithm. The NL-Bayes algorithm uses the Gaussian model instead of the weighted average of all similar patches in th... For random noise suppression of seismic data, we present a non-local Bayes (NL- Bayes) filtering algorithm. The NL-Bayes algorithm uses the Gaussian model instead of the weighted average of all similar patches in the NL-means algorithm to reduce the fuzzy of structural details, thereby improving the denoising performance. In the denoising process of seismic data, the size and the number of patches in the Gaussian model are adaptively calculated according to the standard deviation of noise. The NL-Bayes algorithm requires two iterations to complete seismic data denoising, but the second iteration makes use of denoised seismic data from the first iteration to calculate the better mean and covariance of the patch Gaussian model for improving the similarity of patches and achieving the purpose of denoising. Tests with synthetic and real data sets demonstrate that the NL-Bayes algorithm can effectively improve the SNR and preserve the fidelity of seismic data. 展开更多
关键词 Non-local Bayes random noise suppression BLOCK-MATCHING Gaussian model
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Suppressing random noise to broaden the useful bandwidth of seismic reflection data 被引量:1
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作者 Liu Xuewei Gou Limin 《Applied Geophysics》 SCIE CSCD 2007年第1期37-44,共8页
The signal-to-noise ratio (SNR) of seismic reflection data in many areas is rather poor and conventional two-dimensional filters designed to suppress noise with different moveout from the signal tend to generate art... The signal-to-noise ratio (SNR) of seismic reflection data in many areas is rather poor and conventional two-dimensional filters designed to suppress noise with different moveout from the signal tend to generate artifacts. We have extended a method of multichannel filtering, based on the hypothesis that signals on adjacent channels are similar, for enhancing the SNR on stacked sections. Using only the mid-range frequencies where the SNR is highest, the event trend is found for overlapping windows on the section and the average signal vector is calculated. Then the data from the full bandwidth section are projected onto the spatially varying unit similarity vectors and the results are merged for the overlapping windows. Application of the method to synthetic data containing steeply dipping events and to a stacked section for a marine 2D line has produced good results. The modifications we have introduced carry a small overhead in computing time but they should enable the method to be used effectively even on sections containing steep dips. 展开更多
关键词 noise suppressing signal SNR bandwidth broadening.
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Resonance, Multi-resonance, and Reverse-resonance Induced by Multiplicative Dichotomous Noise 被引量:2
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作者 LI Jing-Hui HAN Yin-Xia 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第4X期605-609,共5页
A constant-potential system driven by multiplicative dichotomous noise and subject to an input oscillatory signal is investigated. Two phenomena of stochastic resonance are observed. One is the response as a function ... A constant-potential system driven by multiplicative dichotomous noise and subject to an input oscillatory signal is investigated. Two phenomena of stochastic resonance are observed. One is the response as a function of the noise's parameters; the other is that as a function of the input signal frequency. A phenomenon of multi-resonance (there are three or four peaks) is found for the response as a function of a parameter of the noise. A phenomenon of reverse-resonance is found, for which the response of the system to the signal can be weakened by the presence of the noise (there is an optimal minimum). These results help in studies of the systems with multiplicative dichotomous noise, such as the semiconductor, the proteins motor, the chemical reaction, and so on. 展开更多
关键词 stochastic resonance dichotomous noise
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Effect of Correlation of Two Dichotomous Noises on Stochastic Resonance 被引量:1
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作者 李东升 李静辉 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第2期298-302,共5页
The effect of the correlation of two dichotomous noises on stochastic resonance is investigated for a linear stochastic system subject to a periodic oscillatory signal. It is found that, the correlation between the tw... The effect of the correlation of two dichotomous noises on stochastic resonance is investigated for a linear stochastic system subject to a periodic oscillatory signal. It is found that, the correlation between the two dichotomous noises can not only affect the appearance of the stochastic resonance phenomenon, but also the distinctness of the stochastic resonance phenomenon. There is an optimal value of the correlation, at which the stochastic resonance phenomenon is most distinct. In addition, the correlation between the two dichotomous noises can also cause the movement of the peak of stochastic resonance. Finally, two stochastic resonances caused by two correlated multiplicative dichotomous noises can be found in this system. 展开更多
关键词 stochastic resonance dichotomous noise CORRELATION
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Application of suppressing random noise in seismic data based on Trivashrink and DTCWT 被引量:1
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作者 WANG Hongye HAN Liguo +1 位作者 LIU Chengming WEI Yajie 《Global Geology》 2014年第4期231-237,共7页
In process of seismic exploration,the noise of seismic signals produces serious interference. Conventional methods of wavelet threshold denoising cannot fully use the characteristics of seismic signals due to its limi... In process of seismic exploration,the noise of seismic signals produces serious interference. Conventional methods of wavelet threshold denoising cannot fully use the characteristics of seismic signals due to its limitations. There is always a certain degree of deviation between estimated value and actual value. In this study,a method of seismic data denoising is proposed,the authors use the current coefficients,the parent coefficients and the neighborhood coefficients based on dual-tree complex wavelet transform( DTCWT) and related sub-band denoising model( TrivaS hrink) to achieve the optimal estimation of shrinking factor and get the noise reduction of seismic records. It is found that the method is better than conventional methods of wavelet threshold denoising in removing random noise. 展开更多
关键词 dual-tree complex wavelet transform Trivashrink threshold seismogram denoising
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