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Assessment of radio observatory sites using a multi-threshold algorithm
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作者 Hang Yang Liang Dong Lesheng He 《Astronomical Techniques and Instruments》 2025年第4期255-264,共10页
Radio environment plays an important role in radio astronomy observations.Further analysis is needed on the time and intensity distributions of interference signals for long-term radio environment monitoring.Sample va... Radio environment plays an important role in radio astronomy observations.Further analysis is needed on the time and intensity distributions of interference signals for long-term radio environment monitoring.Sample variance is an important estimate of the interference signal decision threshold.Here,we propose an improved algorithm for calculating data sample variance relying on four established statistical methods:the variance of the trimmed data,winsorized sample variance,median absolute deviation,and median of the trimmed data pairwise averaged squares method.The variance and decision threshold in the protected section of the radio astronomy L-band are calculated.Among the four methods,the improved median of the trimmed data pairwise averaged squares algorithm has higher accuracy,but in a comparison of overall experimental results,the cleanliness rate of all algorithms is above 96%.In a comparison between the improved algorithm and the four methods,the cleanliness rate of the improved algorithm is above 98%,verifying its feasibility.The time-intensity interference distribution in the radio protection band is also obtained.Finally,we use comprehensive monitoring data of radio astronomy protection bands,radio interference bands,and interfered frequency bands to establish a comprehensive evaluation system for radio observatory sites,including the observable time proportion in the radio astronomy protection band,the occasional time-intensity distribution in the radio interference frequency band,and the intensity distribution of the interfered frequency band. 展开更多
关键词 Radio astronomy Electromagnetic environment threshold algorithm Cleanliness rate
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Defect image segmentation using multilevel thresholding based on firefly algorithm with opposition-learning 被引量:3
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作者 陈恺 戴敏 +2 位作者 张志胜 陈平 史金飞 《Journal of Southeast University(English Edition)》 EI CAS 2014年第4期434-438,共5页
To segment defects from the quad flat non-lead QFN package surface a multilevel Otsu thresholding method based on the firefly algorithm with opposition-learning is proposed. First the Otsu thresholding algorithm is ex... To segment defects from the quad flat non-lead QFN package surface a multilevel Otsu thresholding method based on the firefly algorithm with opposition-learning is proposed. First the Otsu thresholding algorithm is expanded to a multilevel Otsu thresholding algorithm. Secondly a firefly algorithm with opposition-learning OFA is proposed.In the OFA opposite fireflies are generated to increase the diversity of the fireflies and improve the global search ability. Thirdly the OFA is applied to searching multilevel thresholds for image segmentation. Finally the proposed method is implemented to segment the QFN images with defects and the results are compared with three methods i.e. the exhaustive search method the multilevel Otsu thresholding method based on particle swarm optimization and the multilevel Otsu thresholding method based on the firefly algorithm. Experimental results show that the proposed method can segment QFN surface defects images more efficiently and at a greater speed than that of the other three methods. 展开更多
关键词 quad flat non-lead QFN surface defects opposition-learning firefly algorithm multilevel Otsu thresholding algorithm
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An Improved Artificial Immune Algorithm with a Dynamic Threshold 被引量:5
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作者 Zhang Qiao Xu Xu Liang Yan-chun 《Journal of Bionic Engineering》 SCIE EI CSCD 2006年第2期93-97,共5页
An improved artificial immune algorithm with a dynamic threshold is presented. The calculation for the affinity function in the real-valued coding artificial immune algorithm is modified through considering the antib... An improved artificial immune algorithm with a dynamic threshold is presented. The calculation for the affinity function in the real-valued coding artificial immune algorithm is modified through considering the antibody's fitness and setting the dynamic threshold value. Numerical experiments show that compared with the genetic algorithm and the originally real-valued coding artificial immune algorithm, the improved algorithm possesses high speed of convergence and good performance for preventing premature convergence. 展开更多
关键词 dynamic threshold artificial immune algorithm genetic algorithm ANTIBODY
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Dynamic threshold for SPWVD parameter estimation based on Otsu algorithm 被引量:11
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作者 Ning Ma Jianxin Wang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2013年第6期919-924,共6页
Time-frequency-based methods are proven to be effective for parameter estimation of linear frequency modulation (LFM) signals. The smoothed pseudo Winger-Ville distribution (SPWVD) is used for the parameter estima... Time-frequency-based methods are proven to be effective for parameter estimation of linear frequency modulation (LFM) signals. The smoothed pseudo Winger-Ville distribution (SPWVD) is used for the parameter estimation of multi-LFM signals, and a method of the SPWVD binarization by a dynamic threshold based on the Otsu algorithm is proposed. The proposed method is effective in the demand for the estimation of different parameters and the unknown signal-to-noise ratio (SNR) circumstance. The performance of this method is confirmed by numerical simulation. 展开更多
关键词 parameter estimation smoothed pseudo Winger-Ville distribution (SPWVD) dynamic threshold Otsu algorithm
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Optimized quantum singular value thresholding algorithm based on a hybrid quantum computer 被引量:1
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作者 Yangyang Ge Zhimin Wang +9 位作者 Wen Zheng Yu Zhang Xiangmin Yu Renjie Kang Wei Xin Dong Lan Jie Zhao Xinsheng Tan Shaoxiong Li Yang Yu 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第4期752-756,共5页
Quantum singular value thresholding(QSVT) algorithm,as a core module of many mathematical models,seeks the singular values of a sparse and low rank matrix exceeding a threshold and their associated singular vectors.Th... Quantum singular value thresholding(QSVT) algorithm,as a core module of many mathematical models,seeks the singular values of a sparse and low rank matrix exceeding a threshold and their associated singular vectors.The existing all-qubit QSVT algorithm demands lots of ancillary qubits,remaining a huge challenge for realization on nearterm intermediate-scale quantum computers.In this paper,we propose a hybrid QSVT(HQSVT) algorithm utilizing both discrete variables(DVs) and continuous variables(CVs).In our algorithm,raw data vectors are encoded into a qubit system and the following data processing is fulfilled by hybrid quantum operations.Our algorithm requires O [log(MN)] qubits with0(1) qumodes and totally performs 0(1) operations,which significantly reduces the space and runtime consumption. 展开更多
关键词 singular value thresholding algorithm hybrid quantum computation
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Fast recursive algorithm for two-dimensional Tsallis entropy thresholding method 被引量:2
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作者 Tang Yinggan Di Qiuyan Guan Xinping 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第3期619-624,共6页
Recently, a two-dimensional (2-D) Tsallis entropy thresholding method has been proposed as a new method for image segmentation. But the computation complexity of 2-D Tsallis entropy is very large and becomes an obst... Recently, a two-dimensional (2-D) Tsallis entropy thresholding method has been proposed as a new method for image segmentation. But the computation complexity of 2-D Tsallis entropy is very large and becomes an obstacle to real time image processing systems. A fast recursive algorithm for 2-D Tsallis entropy thresholding is proposed. The key variables involved in calculating 2-D Tsallis entropy are written in recursive form. Thus, many repeating calculations are avoided and the computation complexity reduces to O(L2) from O(L4). The effectiveness of the proposed algorithm is illustrated by experimental results. 展开更多
关键词 image segmentation thresholdING Tsallis entropy fast recursive algorithm
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2-D mini mumfuzzy entropy method of image thresholding based on genetic algorithm 被引量:1
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作者 张兴会 刘玲 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2005年第3期557-560,共4页
A new image thresholding method is introduced, which is based on 2-D histgram and minimizing the measures of fuzziness of an input image. A new definition of fuzzy membership function is proposed, it denotes the chara... A new image thresholding method is introduced, which is based on 2-D histgram and minimizing the measures of fuzziness of an input image. A new definition of fuzzy membership function is proposed, it denotes the characteristic relationship between the gray level of each pixel and the average value of its neighborhood. When the threshold is not located at the obvious and deep valley of the histgram, genetic algorithm is devoted to the problem of selecting the appropriate threshold value. The experimental results indicate that the proposed method has good performance. 展开更多
关键词 image thresholding 2-D fuzzy entropy genetic algorithm.
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A Context Sensitive Multilevel Thresholding Using Swarm Based Algorithms 被引量:7
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作者 Shreya Pare Anil Kumar +1 位作者 Varun Bajaj Girish Kumar Singh 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2019年第6期1471-1486,共16页
In this paper, a comprehensive energy function is used to formulate the three most popular objective functions:Kapur's, Otsu and Tsalli's functions for performing effective multilevel color image thresholding.... In this paper, a comprehensive energy function is used to formulate the three most popular objective functions:Kapur's, Otsu and Tsalli's functions for performing effective multilevel color image thresholding. These new energy based objective criterions are further combined with the proficient search capability of swarm based algorithms to improve the efficiency and robustness. The proposed multilevel thresholding approach accurately determines the optimal threshold values by using generated energy curve, and acutely distinguishes different objects within the multi-channel complex images. The performance evaluation indices and experiments on different test images illustrate that Kapur's entropy aided with differential evolution and bacterial foraging optimization algorithm generates the most accurate and visually pleasing segmented images. 展开更多
关键词 COLOR image segmentation Kapur's ENTROPY MULTILEVEL thresholdING OTSU method SWARM based optimization algorithms Tsalli's ENTROPY
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Mean Threshold and ARNN Algorithms for Identification of Eye Commands in an EEG-Controlled Wheelchair
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作者 Nguyen Thanh Hai Nguyen Van Trung Vo Van Toi 《Engineering(科研)》 2013年第10期284-291,共8页
This paper represented Autoregressive Neural Network (ARNN) and meant threshold methods for recognizing eye movements for control of an electrical wheelchair using EEG technology. The eye movements such as eyes open, ... This paper represented Autoregressive Neural Network (ARNN) and meant threshold methods for recognizing eye movements for control of an electrical wheelchair using EEG technology. The eye movements such as eyes open, eyes blinks, glancing left and glancing right related to a few areas of human brain were investigated. A Hamming low pass filter was applied to remove noise and artifacts of the eye signals and to extract the frequency range of the measured signals. An autoregressive model was employed to produce coefficients containing features of the EEG eye signals. The coefficients obtained were inserted the input layer of a neural network model to classify the eye activities. In addition, a mean threshold algorithm was employed for classifying eye movements. Two methods were compared to find the better one for applying in the wheelchair control to follow users to reach the desired direction. Experimental results of controlling the wheelchair in the indoor environment illustrated the effectiveness of the proposed approaches. 展开更多
关键词 AUTOREGRESSIVE NN Model threshold algorithm EEG Technology Eye Activity and Electrical WHEELCHAIR
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Study and Implementation of Web Mining Classification Algorithm Based on Building Tree of Detection Class Threshold
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作者 陈俊杰 宋瀚涛 陆玉昌 《Journal of Beijing Institute of Technology》 EI CAS 2005年第2期126-129,共4页
A new classification algorithm for web mining is proposed on the basis of general classification algorithm for data mining in order to implement personalized information services. The building tree method of detecting... A new classification algorithm for web mining is proposed on the basis of general classification algorithm for data mining in order to implement personalized information services. The building tree method of detecting class threshold is used for construction of decision tree according to the concept of user expectation so as to find classification rules in different layers. Compared with the traditional C4.5 algorithm, the disadvantage of excessive adaptation in C4.5 has been improved so that classification results not only have much higher accuracy but also statistic meaning. 展开更多
关键词 data mining classification algorithm class threshold induced concept
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Extracting Parameters of OFET Before and After Threshold Voltage Using Genetic Algorithms
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作者 Imad Benacer Zohir Dibi 《International Journal of Automation and computing》 EI CSCD 2016年第4期382-391,共10页
This paper presents a compact analytical model for the organic field-effect transistors (OFETs), which describes two main aspects, the first one is related to the behavior in above threshold regime, while the other ... This paper presents a compact analytical model for the organic field-effect transistors (OFETs), which describes two main aspects, the first one is related to the behavior in above threshold regime, while the other corresponds to the below threshold regime. The total drain current in the OFET device is calculated as the sum of two components, with the inclusion of a smooth transition function in order to take into account both regions using a single expression. A genetic algorithm based approach (GA) is investigated as a parameter extraction tool in the case of the compact OFET model to find the parameters' values from experimental data such as: mobility enhancement factor % threshold voltage VTh, subthreshold swing S, channel length modulation A, and knee region sharpness m. The comparison of the developed current model with the experimental data shows a good agreement in terms of the transfer and the output characteristics. Therefore, the GA based approach can be considered as a competitive candidate compared to the direct method. 展开更多
关键词 Organic field effect transistor (OFET) compact model parameter extraction genetic algorithm (GA) threshold regime.
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Reduction of ultrasonic echo noise based on improved wavelet threshold de-noising algorithm for friction welding
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作者 尹欣 张臻 王旻 《China Welding》 EI CAS 2010年第3期61-65,共5页
In the ultrasonic detection of defects in friction welded joints, it is difficult to exactly detect some weak bonding defects because of the noise pollution. This paper proposed an improved threshold function based on... In the ultrasonic detection of defects in friction welded joints, it is difficult to exactly detect some weak bonding defects because of the noise pollution. This paper proposed an improved threshold function based on the multi-resolution analysis wavelet threshold de-noising method which was put forward by Donoho and Johnstone, and applied this method in the de-noising of the defective signals. This threshold function overcomes the discontinuous shortcoming of the hard-threshold function and the disadvantage of soft threshold function which causes an invariable deviation between the estimated wavelet coeffwients and the decomposed wavelet coefficients. The improved threshold function is of simple expression and convenient for calculation. The actual test results of defect noise signal show that this improved method can get less mean square error ( MSE ) and higher signal-to-noise ratio of reconstructed signals than those calculated from hard threshold and soft threshold methods. The improved threshold function has excellent de-noising effect. 展开更多
关键词 wavelet threshold friction welding DE-NOISING improved algorithm
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A lifting-wavelet-based iterative thresholding correction for atomic force microscopy images with vertical distortion
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作者 Yifan Bai Yinan Wu Yongchun Fang 《Nanotechnology and Precision Engineering》 2025年第3期29-40,共12页
To eliminate distortion caused by vertical drift and illusory slopes in atomic force microscopy(AFM)imaging,a lifting-wavelet-based iterative thresholding correction method is proposed in this paper.This method achiev... To eliminate distortion caused by vertical drift and illusory slopes in atomic force microscopy(AFM)imaging,a lifting-wavelet-based iterative thresholding correction method is proposed in this paper.This method achieves high-quality AFM imaging via line-by-line corrections for each distorted profile along the fast axis.The key to this line-by-line correction is to accurately simulate the profile distortion of each scanning row.Therefore,a data preprocessing approach is first developed to roughly filter out most of the height data that impairs the accuracy of distortion modeling.This process is implemented through an internal double-screening mechanism.A line-fitting method is adopted to preliminarily screen out the obvious specimens.Lifting wavelet analysis is then carried out to identify the base parts that are mistakenly filtered out as specimens so as to preserve most of the base profiles and provide a good basis for further distortion modeling.Next,an iterative thresholding algorithm is developed to precisely simulate the profile distortion.By utilizing the roughly screened base profile,the optimal threshold,which is used to screen out the pure bases suitable for distortion modeling,is determined through iteration with a specified error rule.On this basis,the profile distortion is accurately modeled through line fitting on the finely screened base data,and the correction is implemented by subtracting the modeling result from the distorted profile.Finally,the effectiveness of the proposed method is verified through experiments and applications. 展开更多
关键词 Atomic force microscopy Lifting wavelet analysis Iterative thresholding algorithm Vertical distortion
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基于激光测距的深松作业检测技术
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作者 侯云涛 吴泽全 +4 位作者 蔡晓华 东忠阁 程睿 李源源 祝天宇 《农机化研究》 北大核心 2026年第4期110-117,共8页
针对激光测距技术在深松作业检测中的应用进行深入研究,提出了一种自适应多门限值误差拟合方法。算法通过自适应调整多个门限值,动态寻找激光飞行时间误差最佳拟合校正方案,能够有效克服回波信号上升沿鉴别时刻因干扰脉冲产生的误差。... 针对激光测距技术在深松作业检测中的应用进行深入研究,提出了一种自适应多门限值误差拟合方法。算法通过自适应调整多个门限值,动态寻找激光飞行时间误差最佳拟合校正方案,能够有效克服回波信号上升沿鉴别时刻因干扰脉冲产生的误差。基于此方法,研发了一款智能化深松作业检测设备,其能够自主进行耕层断面数据的采集和保存,提高数据采集和处理的效率。同时,开展了测距试验,具体方法为:将SICK DL100-22AA2101激光测距仪的测距值作为标准距离,试验距离为1~4 m,取1 m作为步长,基于所研发设备,采用本文方法与双门限值时刻鉴别方法分别对同一距离进行5次测量作为实测距离,比较实测距离的标准差,以及实测距离均值与对应标准距离的误差。采用本文研发设备和人工方式分别对土壤膨松度和扰动系数进行检测,设备检测结果为土壤蓬松度27.0%、土壤扰动系数22.3%,人工方式检测结果为土壤蓬松度27.1%、土壤扰动系数22.7%。试验证明:研发设备在显著提高测量效率的前提下,得到的测量结果与传统人工测量方式几乎没有差异,具有较高的实用性和可靠性。 展开更多
关键词 深松作业检测 激光测距 自适应多门限值误差拟合算法
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基于自适应多阈值的复杂场景激光图像目标分割方法研究
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作者 周珂 王睿志 +2 位作者 韩继贤 蒋玉华 向兵 《激光杂志》 北大核心 2026年第2期130-135,共6页
传统方法无法适应复杂场景的变化,分割效果不佳,为此提出基于自适应多阈值的复杂场景激光图像目标分割方法。对复杂场景激光图像进行去除噪声处理,通过区域生长将图像划分为多个子区域,然后对每个子区域利用遗传算法获得对应阈值,实现... 传统方法无法适应复杂场景的变化,分割效果不佳,为此提出基于自适应多阈值的复杂场景激光图像目标分割方法。对复杂场景激光图像进行去除噪声处理,通过区域生长将图像划分为多个子区域,然后对每个子区域利用遗传算法获得对应阈值,实现图像自适应多阈值分割,通过合并相似区域和采用形态学操作有效消除过分割现象和图像中的孔洞、毛刺,提高分割结果的清晰度和平滑度,确保分割效果。结果表明:采用所提方法进行复杂场景激光图像目标分割,分割后F1值更高,可达到0.96,结构相似指数更小,为-0.23,能有效提高复杂场景激光图像目标分割效果。 展开更多
关键词 视觉传达 复杂场景激光图像 预处理 遗传算法 多阈值分割
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近岸海域EnviSat卫星测高波形重定的Threshold优化算法 被引量:19
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作者 郭金运 高永刚 +1 位作者 常晓涛 黄金维 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2010年第4期807-814,共8页
波形重定是改善近岸海域卫星测高数据精度的一种有效方法.分析了EnviSat雷达测高波形重定算法,并对Threshold算法进行了优化,开发了波形重定程序;以地中海为实验区,利用几种波形重定方法,对近岸海域的EnviSat测高波形进行重定,认为优化... 波形重定是改善近岸海域卫星测高数据精度的一种有效方法.分析了EnviSat雷达测高波形重定算法,并对Threshold算法进行了优化,开发了波形重定程序;以地中海为实验区,利用几种波形重定方法,对近岸海域的EnviSat测高波形进行重定,认为优化的Threshold算法是几种波形重定算法中最稳健的重定算法,适合于地中海近岸海域EnviSat测高波形的重定,对其他近岸海域的应用也有一定的参考意义. 展开更多
关键词 ENVISAT 卫星测高 波形重定 threshold算法
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基于CPO-ICEEMDAN-WTD的称重信号去噪方法研究
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作者 赵栓峰 闵雨轩 李小雨 《现代电子技术》 北大核心 2026年第6期145-151,共7页
车辆轴重信号去噪对提高动态称重精度有重要的作用。针对噪声干扰问题,文中提出一种基于冠豪猪优化(CPO)算法优化改进自适应噪声完备经验模态分解(ICEEMDAN)、样本熵(SampEn)以及小波软阈值去噪(WTD)的混合信号去噪方法。首先,利用CPO优... 车辆轴重信号去噪对提高动态称重精度有重要的作用。针对噪声干扰问题,文中提出一种基于冠豪猪优化(CPO)算法优化改进自适应噪声完备经验模态分解(ICEEMDAN)、样本熵(SampEn)以及小波软阈值去噪(WTD)的混合信号去噪方法。首先,利用CPO优化ICEEMDAN的白噪声幅值权重和噪声添加次数,并对车辆的轴重信号进行ICEEMDAN分解,得到若干本征模态分量;然后,计算各分量的样本熵,利用阈值判断含噪分量和有用分量,并对含噪分量进行小波软阈值去噪;最后,将处理后的分量与有用分量重构,得到去噪信号。实验结果表明,所提方法可以有效去除原始轴重信号中的噪声,进而提高动态称重系统的测量精度。 展开更多
关键词 动态称重 信号滤波 经验模态分解 小波软阈值去噪 冠豪猪优化算法 信号分解和重构 样本熵
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基于RIME-VMD联合小波阈值的爆破振动信号去噪方法
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作者 王薇 程忠耀 +1 位作者 向延念 宋良俊 《铁道科学与工程学报》 北大核心 2026年第1期465-479,共15页
随着现代化建设的加速推进,邻近既有建筑的爆破作业日益增多,监测和分析爆破引起的振动对结构安全的评估至关重要。然而,爆破振动信号的非线性特性和复杂的环境因素干扰使得从实测信号中提取有效信号成分难度较大,给后续的信号分析造成... 随着现代化建设的加速推进,邻近既有建筑的爆破作业日益增多,监测和分析爆破引起的振动对结构安全的评估至关重要。然而,爆破振动信号的非线性特性和复杂的环境因素干扰使得从实测信号中提取有效信号成分难度较大,给后续的信号分析造成了较大影响。为提高爆破振动信号的降噪精度,将雾凇优化算法(RIME)、变分模态分解(VMD)和小波阈值进行融合,形成一种爆破振动信号联合去噪方法。该方法首先通过雾凇优化算法对VMD关键参数进行优化,然后通过优化后的VMD对振动信号进行自适应分解,剔除方差贡献率较低的分量,再采用小波阈值对筛选后的分量进行降噪处理,最终重构得到去噪后的信号。对该方法的降噪效果进行仿真分析和实际工程验证,结果表明:在仿真信号分析中,经RIME-VMD联合小波阈值的降噪方法去噪后的信号与无噪声的纯净信号相比,形状与特征高度吻合,且信噪比(SNR)和均方根误差(RMSE)等去噪指标优于EMD、小波阈值、EMD联合小波阈值等常用去噪方法;经工程实际案例验证,该方法能够在极大保留原信号基本特征的前提下,有效去除爆破振动信号中的高频噪声,降噪后信号更加符合爆破振动信号的主频范围,且具有比EMD、小波阈值、EMD联合小波阈值等常用去噪方法更好的去噪效果。该研究成果对爆破振动信号的降噪处理具有参考意义。 展开更多
关键词 爆破振动 信号处理 联合降噪 雾凇优化算法 变分模态分解 小波阈值去噪
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‘Outbreak Gold Standard’Selection to Provide Optimized Threshold for Infectious Diseases Early-alert Based on China Infectious Disease Automated-alert and Response System 被引量:5
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作者 王瑞平 姜永根 +2 位作者 赵根明 郭晓芹 Engelgau Michael 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2017年第6期833-841,共9页
The China Infectious Disease Automated-alert and Response System(CIDARS) was successfully implemented and became operational nationwide in 2008. The CIDARS plays an important role in and has been integrated into the... The China Infectious Disease Automated-alert and Response System(CIDARS) was successfully implemented and became operational nationwide in 2008. The CIDARS plays an important role in and has been integrated into the routine outbreak monitoring efforts of the Center for Disease Control(CDC) at all levels in China. In the CIDARS, thresholds are determined using the ?Mean+2SD? in the early stage which have limitations. This study compared the performance of optimized thresholds defined using the ?Mean +2SD? method to the performance of 5 novel algorithms to select optimal ?Outbreak Gold Standard(OGS)? and corresponding thresholds for outbreak detection. Data for infectious disease were organized by calendar week and year. The ?Mean+2 SD?, C1, C2, moving average(MA), seasonal model(SM), and cumulative sum(CUSUM) algorithms were applied. Outbreak signals for the predicted value(Px) were calculated using a percentile-based moving window. When the outbreak signals generated by an algorithm were in line with a Px generated outbreak signal for each week, this Px was then defined as the optimized threshold for that algorithm. In this study, six infectious diseases were selected and classified into TYPE A(chickenpox and mumps), TYPE B(influenza and rubella) and TYPE C [hand foot and mouth disease(HFMD) and scarlet fever]. Optimized thresholds for chickenpox(P_(55)), mumps(P_(50)), influenza(P_(40), P_(55), and P_(75)), rubella(P_(45) and P_(75)), HFMD(P_(65) and P_(70)), and scarlet fever(P_(75) and P_(80)) were identified. The C1, C2, CUSUM, SM, and MA algorithms were appropriate for TYPE A. All 6 algorithms were appropriate for TYPE B. C1 and CUSUM algorithms were appropriate for TYPE C. It is critical to incorporate more flexible algorithms as OGS into the CIDRAS and to identify the proper OGS and corresponding recommended optimized threshold by different infectious disease types. 展开更多
关键词 outbreak gold standard optimized threshold algorithms early-alert signal China Infectious Disease Automated-alert and Response System
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一种改进型Canny的焊缝缺陷快速检测方法
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作者 穆向阳 王宣 《激光杂志》 北大核心 2026年第2期70-76,共7页
针对Canny算法在焊缝缺陷检测中出现边缘信息丢失、检测精度不足以及实时性偏低等问题,提出一种基于FPGA的改进型Canny焊缝缺陷检测方法。首先,该方法将自适应中值滤波和双边滤波技术结合起来,有效抑制噪声的同时最大限度地将焊缝边缘... 针对Canny算法在焊缝缺陷检测中出现边缘信息丢失、检测精度不足以及实时性偏低等问题,提出一种基于FPGA的改进型Canny焊缝缺陷检测方法。首先,该方法将自适应中值滤波和双边滤波技术结合起来,有效抑制噪声的同时最大限度地将焊缝边缘细节保留下来;其次,为了提升边缘提取的完整性,利用高斯加权的Sobel算子计算图像梯度;最后,通过引入基于梯度的自适应多级阈值选择策略,有效连接焊缝边缘的同时提升检测的自适应性。本研究采用FPGA的高速并行处理技术与分层流水线架构,开发了一种在硬件加速平台下的实时边缘检测系统。实验结果表明,该方法在焊缝区域内的边缘连通性较“自适应中值滤波+Canny算法”提升了24%,边缘强度提升了22.7%,并在100 MHz时钟频率下处理一张640×480的图片仅耗时4.1005 ms。本算法在检测精度及实时性方面更具优势,满足复杂环境下对焊缝缺陷检测的相关需求。 展开更多
关键词 CANNY算子 FPGA 自适应中值-双边滤波 自适应多级阈值 并行架构
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