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关键词

临震信号 3

滚动轴承 3

噪声 2

振动信号 2

故障诊断 2

特征提取 2

AD9954 1

AR模型 1

BPSK 1

CFD 1

CMOS；跨导提升技术；低噪声放大器；变压器；共栅级 1

FGR预测 1

RBF神经网络 1

SARS 1

Z干扰信道；非正则信号；和速率；帕累托边界；协方差；伪协方差 1

主动噪声控制（ANC）；过滤扩展最小均方（FXLMS）；模拟计算；遗传算法；内点法 1

事件定位 1

二次防御 1

交通信号控制；交通预测；交通世界模型；强化学习 1

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Target tracking methods based on a signal-to-noise ratio model

Dai Liu, Yong-bo Zhao, Zi-qiao Yuan, Jie-tao Li, Guo-ji Chen,ybzhao@xidian.edu.cn

《信息与电子工程前沿（英文）》 2020年第21卷第12期页码 1671-1814 doi: 10.1631/FITEE.1900679

摘要： In traditional methods, the and are often measured by the empirical value, while observation noise is a constant. In this paper, the and are analyzed. They are influenced by the signal-to-noise ratio (SNR). Therefore, a model related to SNR has been established, in which the SNR information is applied for . Combined with an advanced method, the extended Kalman filter method based on the SNR model (SNR-EKF) and the unscented Kalman filter method based on the SNR model (SNR-UKF) are proposed. There is little difference between the SNR-EKF and SNR-UKF methods in position precision, but the SNR-EKF method has advantages in computation time and the SNR-UKF method has advantages in velocity precision. Simulation results show that methods based on the SNR model can greatly improve the tracking performance compared with traditional tracking methods. The accuracy and convergence speed of the proposed methods have significant improvements.

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De-noising of diesel vibration signal using wavelet packet and singular value decomposition

DUAN Li-xiang, ZHANG Lai-bin, WANG Zhao-hui

《机械工程前沿（英文）》 2006年第1卷第4期页码 443-447 doi: 10.1007/s11465-006-0055-6

摘要： The vibration signals of diesel include excess noise that must be eliminated before extraction of characteristic parameters. Firstly, the effects of vibration-signal de-noising among Fourier transform, wavelet decomposition and wavelet packet decomposition are compared. Secondly, singular value decomposition is applied to de-noising vibration signals. Finally, a new de-noise method integrated with wavelet packet and singular value is presented. In this method, vibration signals are decomposed by wavelet packet, and the wavelet packet coefficient is de-noised by singular value decomposition again. The results indicate that the new de-noising method is the best. The SNR (signal-to-noise ratio) of the vibration signals of a diesel cylinder lid is the highest. The diesel vibration waveforms of combustion and valve become clear and the extracted characteristic parameters become more precise.

关键词： coefficient de-noised cylinder signal-to-noise wavelet decomposition

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Process improvement in laser hot wire cladding for martensitic stainless steel based on the Taguchi method

Zilin HUANG,Gang WANG,Shaopeng WEI,Changhong LI,Yiming RONG

《机械工程前沿（英文）》 2016年第11卷第3期页码 242-249 doi: 10.1007/s11465-016-0397-7

摘要：

Laser hot wire cladding, with the prominent features of low heat input, high energy efficiency, and high precision, is widely used for remanufacturing metal parts. The cladding process, however, needs to be improved by using a quantitative method. In this work, volumetric defect ratio was proposed as the criterion to describe the integrity of forming quality for cladding layers. Laser deposition experiments with FV520B, one of martensitic stainless steels, were designed by using the Taguchi method. Four process variables, namely, laser power (P), scanning speed (V_s), wire feed rate (V_f), and wire current (I), were optimized based on the analysis of signal-to-noise (S/N) ratio. Metallurgic observation of cladding layer was conducted to compare the forming quality and to validate the analysis method. A stable and continuous process with the optimum parameter combination produced uniform microstructure with minimal defects and cracks, which resulted in a good metallurgical bonding interface.

关键词： process optimization Taguchi method signal-to-noise (S/N) ratio volumetric defect ratio laser hot wire cladding

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提高地下金属管振动波测试中冲击响应信号的信噪比

韩修廷,王洁春,焦振强,高飞,宋宇波

《中国工程科学》 2005年第7卷第10期页码 64-68

摘要：

提出了在套损振动波检测过程中提高信号信噪比的方法。检测过程中，在井口敲击套管并接收、分析套管的回波，以了解介质的变化情况。由于反射波信号强度较微弱，单纯用一组接收信号无法进行正确的套损分析，采用信号增强方法，即利用多个类似信号进行叠加，增强反射波的有效信号，降低背景噪声，从而得到有用信息，进行正确的套损状况分析。开发了相应的信号处理软件，提高了信号处理速度。通过10井次的测试表明，技术原理可行，软件工作稳定、可靠，便于操作，可以进行多种方法的信号处理，极大地提高了工作效率。

关键词：振动波反射波信号增强信号叠加

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微地震监测技术探究

唐春华,顾广庆

《中国工程科学》 2012年第14卷第4期页码 95-99

摘要：

微地震监测是地球物理学中的一个重要研究方向，它在油田勘探开采等众多领域有广泛的应用。从微地震的形成机理出发，介绍了微地震的发展历程。重点讨论了微地震监测系统的重要组成部分、关键技术和微地震监测的具体实施，最后讨论了微地震未来的发展与趋势。

关键词：微地震监测水力压裂石油天然气信噪比事件定位

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Adaptive robust beamformer formulti-pair two-way relay networks with imperfect channel state information

Jin WANG,Feng SHU,Ri-qing CHEN,Yu-di CUI,Yu CHEN,Jun LI

《信息与电子工程前沿（英文）》 2016年第17卷第3期页码 265-280 doi: 10.1631/FITEE.1500134

摘要： In wideband multi-pair two-way relay networks, the performance of beamforming at a relay station (RS) is intimately related to the accuracy of the channel state information (CSI) available. The accuracy of CSI is determined by Doppler spread, delay between beamforming and channel estimation, and density of pilot symbols, including transmit power of pilot symbols. The coefficient of the Gaussian-Markov CSI error model is modeled as a function of CSI delay, Doppler spread, and signal-to-noise ratio, and can be estimated in real time. In accordance with the real-time estimated coefficients of the error model, an adaptive robust maximum signal-to-interferenceand- noise ratio (Max-SINR) plus maximum signal-to-leakage-and-noise ratio (Max-SLNR) beamformer at an RS is proposed to track the variation of the CSI error. From simulation results and analysis, it is shown that: compared to existing non-adaptive beamformers, the proposed adaptive beamformer is more robust and performs much better in the sense of bit error rate (BER); with increase in the density of transmit pilot symbols, its BER and sum-rate performances tend to those of the beamformer of Max-SINR plus Max-SLNR with ideal CSI.

关键词： Multi-pair two-way relay Adaptive robust beamformer Channel state information (CSI) Maximum signal-to-interference-and-noise ratio (Max-SINR) Maximum signal-to-leakage-and-noise ratio (Max-SLNR)

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基于经验模式分解的旋转机械振动信号降噪处理

杨建文,贾民平,许飞云,胡建中

《中国工程科学》 2005年第7卷第8期页码 66-69

摘要：

分析了经验模式分解的滤波性能；针对旋转机械振动信号信噪比低及非平稳特性，应用经验模式分解对振动信号进行降噪处理，突出了有用振动信号，为旋转机械在线监测和故障诊断提供了有效的依据；仿真实验及真实数据分析表明，经验模式分解在振动信号降噪处理中是有效的，为振动信号分析提供了新的方法。

关键词：故障诊断经验模式分解旋转机械滤波

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Wavelet-based iterative data enhancement for implementation in purification of modal frequency for extremely noisy ambient vibration tests in Shiraz-Iran

Hassan YOUSEFI, Alireza TAGHAVI KANI, Iradj MAHMOUDZADEH KANI, Soheil MOHAMMADI

《结构与土木工程前沿（英文）》 2020年第14卷第2期页码 446-472 doi: 10.1007/s11709-019-0605-8

摘要： The main purpose of the present study is to enhance high-level noisy data by a wavelet-based iterative filtering algorithm for identification of natural frequencies during ambient wind vibrational tests on a petrochemical process tower. Most of denoising methods fail to filter such noise properly. Both the signal-to-noise ratio and the peak signal-to-noise ratio are small. Multiresolution-based one-step and variational-based filtering methods fail to denoise properly with thresholds obtained by theoretical or empirical method. Due to the fact that it is impossible to completely denoise such high-level noisy data, the enhancing approach is used to improve the data quality, which is the main novelty from the application point of view here. For this iterative method, a simple computational approach is proposed to estimate the dynamic threshold values. Hence, different thresholds can be obtained for different recorded signals in one ambient test. This is in contrast to commonly used approaches recommending one global threshold estimated mainly by an empirical method. After the enhancements, modal frequencies are directly detected by the cross wavelet transform (XWT), the spectral power density and autocorrelation of wavelet coefficients. Estimated frequencies are then compared with those of an undamaged-model, simulated by the finite element method.

关键词： ambient vibration test high level noise iterative signal enhancement wavelet cross and autocorrelation of wavelets

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Ambient noise tomography for coral islands

Shaohong Xia,Changrong Zhang,Jinghe Cao,

《工程（英文）》 doi: 10.1016/j.eng.2021.09.022

摘要： As valuable land in the ocean, coral islands are not only important bases for making use of marine resources and protecting marine rights and interests, but also important for breakthrough research in many fields of earth science. Hence, the economical and efficient determination of the underground structure of coral islands has become significant in coral island engineering geology, but remains challenging for traditional marine geophysical prospecting and drilling methods. While ambient noise tomography with dense arrays has been widely used in continental regions, its applicability to coral islands remains undetermined. In this study, based on the data recorded by a dense array on an isolated coral island in the South China Sea, we analyzed the ambient noise characteristics and obtained a 3D subsurface structure of the coral island using ambient noise tomography. We made the following findings: ① The ambient noise frequencies can be roughly categorized into three levels: < 1, 1–5, and > 5 Hz. The spectral characteristics of the noise below 5 Hz were consistent at different stations, but there were significant differences in the characteristics of the noise above 5 Hz. ② For ambient noise frequencies below 5 Hz, cross-correlation functions with high quality could be obtained with only 24 h of waveform data. However, it was difficult to extract meaningful cross-correlation functions for ambient noise frequencies above 5 Hz. ③ The S-wave velocity in the coral island was higher toward the sea and lower toward the lagoon, which was consistent with the high degree of cementation of the outer reef flat stratum on the seaward side. ④ There were two low-velocity horizons at 25–75 and 200–300 m, which were in good agreement with the high-porosity horizons that were revealed by drilling core samples, reflecting the weathering history of the reef. Our research demonstrates that ambient noise tomography is a potentially economical, efficient, and environmentally friendly method for the geological prospecting of coral reefs.

关键词： Coral island Ambient noise tomography Engineering geology South China Sea

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基于特征分析和最大信干噪比波束形成器的鲁棒广义旁瓣消除器 Research Articles

Quan-dong WANG, Liang-hao GUO, Wei-yu ZHANG, Sui-ling REN, Chao YAN

《信息与电子工程前沿（英文）》 2019年第20卷第7期页码 975-987 doi: 10.1631/FITEE.1700367

摘要：提出一种鲁棒的广义旁瓣消除器抵抗到达方向失配的影响。为估计干扰加噪声的统计特性，传统信号提取方法常需收集大量仅存在干扰噪声的信号片段。为避免该收集过程，我们使用特征分析方法重新设计阻塞矩阵结构，从接收样本中重建干扰噪声的协方差矩阵。另外，基于秩-1矩阵假设，改进特征分析重建方法，以实现更高重建精度。将该重建方法与最大信干噪声比波束形成器结合，获得阻塞矩阵，最大限度减少信号泄漏的影响，并最大化干扰噪声功率，以进一步在最终输出中抑制噪声和干扰成分。数值结果表明，在存在到达方向失配和快照数有限的情况下，上述两种方法在输出波形信干噪比和与期望信号的相关系数方面有显著改进。与所提第一种方法相比，改进后的方法可进一步减少信号失真。

关键词：特征分析；干扰噪声协方差矩阵重建；最大信干噪比准则；阻塞矩阵；广义旁瓣消除器；到达方向失配

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Design of noise-reduction seats for high-speed trains

Xiaojun DENG, Yanju ZHAO, Haijin ZHANG, Renzhong SHUAI, Leiwei ZHU

《机械工程前沿（英文）》 2018年第13卷第3期页码 385-389 doi: 10.1007/s11465-017-0438-x

摘要：

Noise-reduction seats have been successfully used in concert halls, theaters, and other places that reduce noise. In this study, a new noise-reduction seat design was proposed for high-speed trains, which have unique interior noise spectral characteristics. First, before the noise-reduction seat models were fabricated, the parameters of high-performance sound-absorbing materials and perforated plates were selected by conducting a standing-wave tube test. The sound-absorption effects of the noise-reduction seats and normal seats were investigated and compared in a reverberation chamber. Test results showed that, compared with normal seats, the noise-reduction seats obtained a significantly improved sound-absorption coefficient in the entire frequency band. Furthermore, the test results were used to establish a simulation model for calculation, and the simulation results proved that the noise-reduction seats substantially reduced the noise in an entire train car. Finally, the noise-reduction seats were fabricated and installed in a full train car of an actual high-speed train. The test results showed that, compared with the normal seats, the noise-reduction seats decreased the noise level at a standard point in the passenger car by 1.5 dB. Therefore, the noise-reduction seats are effective in noise reduction.

关键词： high-speed train sound-absorbing materials perforated board noise-reduction seats

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CHARACTERISTICS OF HERBIVORY/WOUND-ELICITED ELECTRICAL SIGNAL TRANSDUCTION IN TOMATO

《农业科学与工程前沿（英文）》 2021年第8卷第2期

摘要：

Electrical signals commonly occur in plants in response to various environmental changes and have a dominant function in plant acclimation. The transduction of wound-elicited electrical signals in the model plant species Arabidopsis has been characterized but the characteristics of electrical signal transduction in response to herbivory or wounding in crop species remain unknown. Here, the features of electrical signals elicited by insect herbivory and wounding in tomato were investigated. Unlike those in Arabidopsis, wounding tomato leaves did not cause leaf-to-leaf electrical signal transduction. In contrast, electrical signals elicited in response to petiole wounding were stronger and more strongly transduced. Leaflet wounding also activated electrical signal transduction and jasmonic acid (JA) signaling within the whole compound leaf. It was also demonstrated that tomato glutamate receptor-like 3.3 (GLR3.3) and GLR3.5 mediated leaflet-to-leaflet electrical signal transduction. Herbivory-induced JA accumulation and Helicoverpa armigera resistance were reduced in glr3.3/3.5 plants. This work reveals the nature of electrical signal transduction in tomato and emphasizes the key roles of GLR3.3 and GLR3.5 in electrical signal transduction and JA signaling activation.

关键词： electrical signal / glutamate receptor-like / herbivory / jasmonic acid / tomato

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Anovel approach of noise statistics estimate using H∞ filter in target tracking

Xie WANG,Mei-qin LIU,Zhen FAN,Sen-lin ZHANG

《信息与电子工程前沿（英文）》 2016年第17卷第5期页码 449-457 doi: 10.1631/FITEE.1500262

摘要： Noise statistics are essential for estimation performance. In practical situations, however, a priori information of noise statistics is often imperfect. Previous work on noise statistics identification in linear systems still requires initial prior knowledge of the noise. A novel approach is presented in this paper to solve this paradox. First, we apply the H∞ filter to obtain the system state estimates without the common assumptions about the noise in conventional adaptive filters. Then by applying state estimates obtained from the H∞ filter, better estimates of the noise mean and covariance can be achieved, which can improve the performance of estimation. The proposed approach makes the best use of the system knowledge without a priori information with modest computation cost, which makes it possible to be applied online. Finally, numerical examples are presented to show the efficiency of this approach.

关键词： Noise estimate H∞ filter Target tracking

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Acoustic fault signal extraction via the line-defect phononic crystals

《机械工程前沿（英文）》 2022年第17卷第1期页码 10-10 doi: 10.1007/s11465-021-0666-y

摘要： Rotating machine fault signal extraction becomes increasingly important in practical engineering applications. However, fault signals with low signal-to-noise ratios (SNRs) are difficult to extract, especially at the early stage of fault diagnosis. In this paper, 2D line-defect phononic crystals (PCs) consisting of periodic acrylic tubes with slit are proposed for weak signal detection. The defect band, namely, the formed resonance band of line-defect PCs enables the incident acoustic wave at the resonance frequency to be trapped and enhanced at the resonance cavity. The noise can be filtered by the band gap. As a result, fault signals with high SNRs can be obtained for fault feature extraction. The effectiveness of weak harmonic and periodic impulse signal detection via line-defect PCs are investigated in numerical and experimental studies. All the numerical and experimental results indicate that line-defect PCs can be well used for extracting weak harmonic and periodic impulse signals. This work will provide potential for extracting weak signals in many practical engineering applications.

关键词： phononic crystals line-defect fault signal extraction acoustic enhancement

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Investigation of flow dynamics and decrease of vortex noise inside volute of centrifugal fans

LI Chunxi, WANG Songling

《能源前沿（英文）》 2008年第2卷第2期页码 235-240 doi: 10.1007/s11708-008-0040-3

摘要： The characteristics of three-dimension flow dynamics inside the volute of a G4-73No.8D centrifugal fan was simulated numerically using a computational fluid dynamics(CFD) technique. The generation, evolution, and noise of the vortex were investigated when cylinder-shaped and cone-cylinder-shaped anti-vortex rings were added separately. Numerical results showed that large-scale vortices were broken effectively and the flow fields inside the fan were more uniform with the two anti-vortex rings installed. Experimental results indicated A-sound level and spectrum noise of the refitted fan decreased and the two anti-vortex rings were effective in decreasing vortex noise. The cone-cylinder-shaped anti-vortex ring was more effective than the cylinder-shaped one in breaking large-scale vortexes and decreasing vortex noise.

关键词： cylinder-shaped evolution computational effective large-scale

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标题作者时间类型操作

Target tracking methods based on a signal-to-noise ratio model

Dai Liu, Yong-bo Zhao, Zi-qiao Yuan, Jie-tao Li, Guo-ji Chen,ybzhao@xidian.edu.cn

期刊论文

De-noising of diesel vibration signal using wavelet packet and singular value decomposition

DUAN Li-xiang, ZHANG Lai-bin, WANG Zhao-hui

期刊论文

Process improvement in laser hot wire cladding for martensitic stainless steel based on the Taguchi method

Zilin HUANG,Gang WANG,Shaopeng WEI,Changhong LI,Yiming RONG

期刊论文

提高地下金属管振动波测试中冲击响应信号的信噪比

韩修廷,王洁春,焦振强,高飞,宋宇波

期刊论文

微地震监测技术探究

唐春华,顾广庆

期刊论文

Adaptive robust beamformer formulti-pair two-way relay networks with imperfect channel state information

Jin WANG,Feng SHU,Ri-qing CHEN,Yu-di CUI,Yu CHEN,Jun LI

期刊论文

基于经验模式分解的旋转机械振动信号降噪处理

杨建文,贾民平,许飞云,胡建中

期刊论文

Wavelet-based iterative data enhancement for implementation in purification of modal frequency for extremely noisy ambient vibration tests in Shiraz-Iran

Hassan YOUSEFI, Alireza TAGHAVI KANI, Iradj MAHMOUDZADEH KANI, Soheil MOHAMMADI

期刊论文

Ambient noise tomography for coral islands

Shaohong Xia,Changrong Zhang,Jinghe Cao,

期刊论文

基于特征分析和最大信干噪比波束形成器的鲁棒广义旁瓣消除器

Quan-dong WANG, Liang-hao GUO, Wei-yu ZHANG, Sui-ling REN, Chao YAN

期刊论文

Design of noise-reduction seats for high-speed trains

Xiaojun DENG, Yanju ZHAO, Haijin ZHANG, Renzhong SHUAI, Leiwei ZHU

期刊论文

CHARACTERISTICS OF HERBIVORY/WOUND-ELICITED ELECTRICAL SIGNAL TRANSDUCTION IN TOMATO