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Identification of denatured and normal biological tissues based on compressed sensing and refined composite multi-scale fuzzy entropy during high intensity focused ultrasound treatment 被引量:4
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作者 Shang-Qu Yan Han Zhang +2 位作者 Bei Liu Hao Tang Sheng-You Qian 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第2期601-607,共7页
In high intensity focused ultrasound(HIFU)treatment,it is crucial to accurately identify denatured and normal biological tissues.In this paper,a novel method based on compressed sensing(CS)and refined composite multi-... In high intensity focused ultrasound(HIFU)treatment,it is crucial to accurately identify denatured and normal biological tissues.In this paper,a novel method based on compressed sensing(CS)and refined composite multi-scale fuzzy entropy(RCMFE)is proposed.First,CS is used to denoise the HIFU echo signals.Then the multi-scale fuzzy entropy(MFE)and RCMFE of the denoised HIFU echo signals are calculated.This study analyzed 90 cases of HIFU echo signals,including 45 cases in normal status and 45 cases in denatured status,and the results show that although both MFE and RCMFE can be used to identify denatured tissues,the intra-class distance of RCMFE on each scale factor is smaller than MFE,and the inter-class distance is larger than MFE.Compared with MFE,RCMFE can calculate the complexity of the signal more accurately and improve the stability,compactness,and separability.When RCMFE is selected as the characteristic parameter,the RCMFE difference between denatured and normal biological tissues is more evident than that of MFE,which helps doctors evaluate the treatment effect more accurately.When the scale factor is selected as 16,the best distinguishing effect can be obtained. 展开更多
关键词 compressed sensing high intensity focused ultrasound(HIFU)echo signal multi-scale fuzzy entropy refined composite multi-scale fuzzy entropy
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Radar emitter signal recognition based on multi-scale wavelet entropy and feature weighting 被引量:16
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作者 李一兵 葛娟 +1 位作者 林云 叶方 《Journal of Central South University》 SCIE EI CAS 2014年第11期4254-4260,共7页
In modern electromagnetic environment, radar emitter signal recognition is an important research topic. On the basis of multi-resolution wavelet analysis, an adaptive radar emitter signal recognition method based on m... In modern electromagnetic environment, radar emitter signal recognition is an important research topic. On the basis of multi-resolution wavelet analysis, an adaptive radar emitter signal recognition method based on multi-scale wavelet entropy feature extraction and feature weighting was proposed. With the only priori knowledge of signal to noise ratio(SNR), the method of extracting multi-scale wavelet entropy features of wavelet coefficients from different received signals were combined with calculating uneven weight factor and stability weight factor of the extracted multi-dimensional characteristics. Radar emitter signals of different modulation types and different parameters modulated were recognized through feature weighting and feature fusion. Theoretical analysis and simulation results show that the presented algorithm has a high recognition rate. Additionally, when the SNR is greater than-4 d B, the correct recognition rate is higher than 93%. Hence, the proposed algorithm has great application value. 展开更多
关键词 emitter recognition multi-scale wavelet entropy feature weighting uneven weight factor stability weight factor
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The Study of Image Segmentation Based on the Combination of the Wavelet Multi-scale Edge Detection and the Entropy Iterative Threshold Selection 被引量:3
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作者 ZHANG Qian HE Jian-feng +3 位作者 MA Lei PAN Li-peng LIU Jun-qing CHEN Hong-lei 《Chinese Journal of Biomedical Engineering(English Edition)》 2013年第4期154-160,共7页
This paper proposes an image segmentation method based on the combination of the wavelet multi-scale edge detection and the entropy iterative threshold selection.Image for segmentation is divided into two parts by hig... This paper proposes an image segmentation method based on the combination of the wavelet multi-scale edge detection and the entropy iterative threshold selection.Image for segmentation is divided into two parts by high- and low-frequency.In the high-frequency part the wavelet multiscale was used for the edge detection,and the low-frequency part conducted on segmentation using the entropy iterative threshold selection method.Through the consideration of the image edge and region,a CT image of the thorax was chosen to test the proposed method for the segmentation of the lungs.Experimental results show that the method is efficient to segment the interesting region of an image compared with conventional methods. 展开更多
关键词 wavelet multi-scale entropy iterative threshold lung images
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Multi-scale complexity entropy causality plane: An intrinsic measure for indicating two-phase flow structures
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作者 窦富祥 金宁德 +2 位作者 樊春玲 高忠科 孙斌 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第12期85-96,共12页
We extend the complexity entropy causality plane(CECP) to propose a multi-scale complexity entropy causality plane(MS-CECP) and further use the proposed method to discriminate the deterministic characteristics of ... We extend the complexity entropy causality plane(CECP) to propose a multi-scale complexity entropy causality plane(MS-CECP) and further use the proposed method to discriminate the deterministic characteristics of different oil-in-water flows. We first take several typical time series for example to investigate the characteristic of the MS-CECP and find that the MS-CECP not only describes the continuous loss of dynamical structure with the increase of scale, but also reflects the determinacy of the system. Then we calculate the MS-CECP for the conductance fluctuating signals measured from oil–water two-phase flow loop test facility. The results indicate that the MS-CECP could be an intrinsic measure for indicating oil-in-water two-phase flow structures. 展开更多
关键词 oil–water two-phase flow fluid dynamics complexity entropy multi-scale
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Upper bound for the time derivative of entropy for a stochastic dynamical system with double singularities driven by non-Gaussian noise 被引量:2
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作者 郭培荣 徐伟 刘迪 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第3期233-238,共6页
A stochastic dynamical system with double singularities driven by non-Gaussian noise is investigated. The Fokker Plank equation of the system is obtained through the path-integral approach and the method of transforma... A stochastic dynamical system with double singularities driven by non-Gaussian noise is investigated. The Fokker Plank equation of the system is obtained through the path-integral approach and the method of transformation. Based on the definition of Shannon's information entropy and the Schwartz inequality principle, the upper bound for the time derivative of entropy is calculated both in the absence and in the presence of non-equilibrium constraint. The present calculations can be used to interpret the effects of the system dissipative parameter, the system singularity strength parameter, the noise correlation time and the noise deviation parameter on the upper bound. 展开更多
关键词 non-Gaussian noise stochastic dynamical system with double singularities informationentropy upper bound for the time derivative of entropy
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Analysis of heart rate variability based on singular value decomposition entropy 被引量:2
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作者 李世阳 杨明 +1 位作者 李存岑 蔡萍 《Journal of Shanghai University(English Edition)》 CAS 2008年第5期433-437,共5页
Assessing the dynamics of heart rate fluctuations can provide valuable information about heart status. In this study, regularity of heart rate variability (HRV) of heart failure patients and healthy persons using th... Assessing the dynamics of heart rate fluctuations can provide valuable information about heart status. In this study, regularity of heart rate variability (HRV) of heart failure patients and healthy persons using the concept of singular value decomposition entropy (SvdEn) is analyzed. SvdEn is calculated from the time series using normalized singular values. The advantage of this method is its simplicity and fast computation. It enables analysis of very short and non-stationary data sets. The results show that SvdEn of patients with congestive heart failure (CHF) shows a low value (SvdEn: 0.056±0.006, p 〈 0.01) which can be completely separated from healthy subjects. In addition, differences of SvdEn values between day and night are found for the healthy groups. SvdEn decreases with age. The lower the SvdEn values, the higher the risk of heart disease. Moreover, SvdEn is associated with the energy of heart rhythm. The results show that using SvdEn for discriminating HRV in different physiological states for clinical applications is feasible and simple. 展开更多
关键词 heart rate variability (HRV) singular value decomposition (SVD) entropy congestive heart failure (CHF)
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High impedance fault detection in distribution network based on S-transform and average singular entropy 被引量:4
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作者 Xiaofeng Zeng Wei Gao Gengjie Yang 《Global Energy Interconnection》 EI CAS CSCD 2023年第1期64-80,共17页
When a high impedance fault(HIF)occurs in a distribution network,the detection efficiency of traditional protection devices is strongly limited by the weak fault information.In this study,a method based on S-transform... When a high impedance fault(HIF)occurs in a distribution network,the detection efficiency of traditional protection devices is strongly limited by the weak fault information.In this study,a method based on S-transform(ST)and average singular entropy(ASE)is proposed to identify HIFs.First,a wavelet packet transform(WPT)was applied to extract the feature frequency band.Thereafter,the ST was investigated in each half cycle.Afterwards,the obtained time-frequency matrix was denoised by singular value decomposition(SVD),followed by the calculation of the ASE index.Finally,an appropriate threshold was selected to detect the HIFs.The advantages of this method are the ability of fine band division,adaptive time-frequency transformation,and quantitative expression of signal complexity.The performance of the proposed method was verified by simulated and field data,and further analysis revealed that it could still achieve good results under different conditions. 展开更多
关键词 High impedance fault(HIF) Wavelet packet transform(WPT) S-transform(ST) singular entropy(SE)
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Time evolution of information entropy for a stochastic system with double singularities driven by quasimonochromatic noise 被引量:1
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作者 郭永峰 谭建国 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第12期99-103,共5页
This paper deals with the time evolution of information entropy for a stochastic system with double singularities driven by quasimonochromatic noise. The dimension of the Fokker Planck equation is reduced by the linea... This paper deals with the time evolution of information entropy for a stochastic system with double singularities driven by quasimonochromatic noise. The dimension of the Fokker Planck equation is reduced by the linear transfor- mation. The exact expression of the time dependence of information entropy is obtained based on the definition of Shannon's information entropy. The relationships between the properties of dissipative parameters, system singularity strength parameter, quasimonochromatic noise, and their effects on information entropy are discussed. 展开更多
关键词 information entropy quasimonochromatic noise Fokker-Planck equation stochastic sys-tem with double singularities
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Denoising Nonlinear Time Series Using Singular Spectrum Analysis and Fuzzy Entropy 被引量:1
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作者 江剑 谢洪波 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第10期19-23,共5页
We present a hybrid singular spectrum analysis (SSA) and fuzzy entropy method to filter noisy nonlinear time series. With this approach, SSA decomposes the noisy time series into its constituent components including... We present a hybrid singular spectrum analysis (SSA) and fuzzy entropy method to filter noisy nonlinear time series. With this approach, SSA decomposes the noisy time series into its constituent components including both the deterministic behavior and noise, while fuzzy entropy automatically differentiates the optimal dominant components from the noise based on the complexity of each component. We demonstrate the effectiveness of the hybrid approach in reconstructing the Lorenz and Mackey--Class attractors, as well as improving the multi-step prediction quality of these two series in noisy environments. 展开更多
关键词 of on or in Denoising Nonlinear Time Series Using singular Spectrum Analysis and Fuzzy entropy NLP IS
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A Fault Diagnosis Method Based on Wavelet Singular Entropy and SVM for VSC-HVDC Converter 被引量:1
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作者 XU Bingbing WANG Tianzhen +1 位作者 LUO Kai GAO Diju 《Wuhan University Journal of Natural Sciences》 CAS CSCD 2020年第4期359-368,共10页
The converter is the core component of voltage source converter-high voltage direct current(VSC-HVDC),which is related to the stable operation of the system.The converter has a complex structure where the accuracy of ... The converter is the core component of voltage source converter-high voltage direct current(VSC-HVDC),which is related to the stable operation of the system.The converter has a complex structure where the accuracy of feature extraction is low,and the computation speed of traditional fault diagnosis strategies is slow.To solve this problem,a fault diagnosis strategy based on wavelet singular entropy(WSE)and support vector machine(SVM)was proposed.This method includes fault and label setting,converter fault feature extraction based on wavelet singular entropy,and converter fault classification based on support vector machine.The DC-side voltage signal was used as the detection signal,and the wavelet singular entropy was used for feature extraction to avoid noise interference.The classification is based on SVM.The experimental verification in PSCAD simulation proved that the method has better fault diagnosis ability for various faults and meets the needs of converter fault diagnosis. 展开更多
关键词 CONVERTER wavelet singular entropy fault diagnosis support vector machine
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Short-Term Prediction of Photovoltaic Power Generation Based on LMD Permutation Entropy and Singular Spectrum Analysis 被引量:1
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作者 Wenchao Ma 《Energy Engineering》 EI 2023年第7期1685-1699,共15页
The power output state of photovoltaic power generation is affected by the earth’s rotation and solar radiation intensity.On the one hand,its output sequence has daily periodicity;on the other hand,it has discrete ra... The power output state of photovoltaic power generation is affected by the earth’s rotation and solar radiation intensity.On the one hand,its output sequence has daily periodicity;on the other hand,it has discrete randomness.With the development of new energy economy,the proportion of photovoltaic energy increased accordingly.In order to solve the problem of improving the energy conversion efficiency in the grid-connected optical network and ensure the stability of photovoltaic power generation,this paper proposes the short-termprediction of photovoltaic power generation based on the improvedmulti-scale permutation entropy,localmean decomposition and singular spectrum analysis algorithm.Firstly,taking the power output per unit day as the research object,the multi-scale permutation entropy is used to calculate the eigenvectors under different weather conditions,and the cluster analysis is used to reconstruct the historical power generation under typical weather rainy and snowy,sunny,abrupt,cloudy.Then,local mean decomposition(LMD)is used to decompose the output sequence,so as to extract more detail components of the reconstructed output sequence.Finally,combined with the weather forecast of the Meteorological Bureau for the next day,the singular spectrumanalysis algorithm is used to predict the photovoltaic classification of the recombination decomposition sequence under typical weather.Through the verification and analysis of examples,the hierarchical prediction experiments of reconstructed and non-reconstructed output sequences are compared.The results show that the algorithm proposed in this paper is effective in realizing the short-term prediction of photovoltaic generator,and has the advantages of simple structure and high prediction accuracy. 展开更多
关键词 Photovoltaic power generation short term forecast multiscale permutation entropy local mean decomposition singular spectrum analysis
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Research on the detecting methods of singularity in deformation signal based on two kinds of wavelet entropy
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作者 ZHANG Hua-rong QU Guo-qing RENTing 《Journal of Coal Science & Engineering(China)》 2012年第2期213-217,共5页
There are various influencing factors that affect the deformation observation, and deformation signals show differ- ent characteristics under different scales. Wavelet analysis possesses multi-scale property, and the ... There are various influencing factors that affect the deformation observation, and deformation signals show differ- ent characteristics under different scales. Wavelet analysis possesses multi-scale property, and the information entropy has great representational capability to the complexity of information. By hamming window to the wavelet coefficients and windowed wavelet energy obtained by multi-resolution analysis (MRA), it can be achieved to measure the wavelet time entropy (WTE) and wavelet energy entropy (WEE). The paper established deformation signals, selected the parameters, and compared the sin- gularity detection ability and anti-noise ability of two kinds of wavelet entropy and applied them to the singularity detection at the GPS continuously operating reference stations. It is shown that the WTE performs well in weak singularity information de- tection in finite frequency components signals and the WEE is more suitable for detecting the singularity in the signals with complex, strong background noise. 展开更多
关键词 deformation signal wavelet time entropy wavelet energy entropy singularity detection
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Wi-Wheat+:Contact-free wheat moisture sensing with commodity WiFi based on entropy 被引量:1
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作者 Weidong Yang Erbo Shen +3 位作者 Xuyu Wang Shiwen Mao Yuehong Gong Pengming Hu 《Digital Communications and Networks》 SCIE CSCD 2023年第3期698-709,共12页
In this paper,we propose a contact-free wheat moisture monitoring system,termed Wi-Wheatþ,to address the several limitations of the existing grain moisture detection technologies,such as time-consuming process,ex... In this paper,we propose a contact-free wheat moisture monitoring system,termed Wi-Wheatþ,to address the several limitations of the existing grain moisture detection technologies,such as time-consuming process,expensive equipment,low accuracy,and difficulty in real-time monitoring.The proposed system is based on Commodity WiFi and is easy to deploy.Leveraging WiFi CSI data,this paper proposes a feature extraction method based on multi-scale and multi-channel entropy.The feasibility and stability of the system are validated through experiments in both Line-Of-Sight(LOS)and Non-Line-Of-Sight(NLOS)scenarios,where ten types of wheat moisture content are tested using multi-class Support Vector Machine(SVM).Compared with the Wi-Wheat system proposed in our prior work,Wi-Wheatþhas higher efficiency,requiring only a simple training process,and can sense more wheat moisture content levels. 展开更多
关键词 Channel state information(CSI) WIFI multi-scale entropy Multi-class support vector machine(SVM) Radio frequency(RF)sensing
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Dense Fractal Networks, Trends, Noises and Switches in Homeostasis Regulation of Shannon Entropy for Chromosomes’ Activity in Living Cells for Medical Diagnostics
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作者 Nikolay E. Galich 《Applied Mathematics》 2013年第11期30-41,共12页
We analyze correlations and patterns of oxidative activity of 3D DNA at DNA fluorescence in complete sets of chromosomes in neutrophils of peripheral blood. Fluorescence of DNA is registered by method of flow cytometr... We analyze correlations and patterns of oxidative activity of 3D DNA at DNA fluorescence in complete sets of chromosomes in neutrophils of peripheral blood. Fluorescence of DNA is registered by method of flow cytometry with nanometer spatial resolution. Experimental data present fluorescence of many ten thousands of cells, from different parts of body in each population, in various blood samples. Data is presented in histograms as frequency distributions of flashes in the dependence on their intensity. Normalized frequency distribution of information in these histograms is used as probabilistic measure for definition of Shannon entropy. Data analysis shows that for this measure of Shannon entropy common sum of entropy, i.e. total entropy E, for any histogram is invariant and has identical trends of changes all values of E (r) = lnr at reduction of rank r of histogram. This invariance reflects informational homeostasis of chromosomes activity inside cells in multi-scale networks of entropy, for varied ranks r. Shannon entropy in multi-scale DNA networks has much more dense packing of correlations than in “small world” networks. As the rule, networks of entropy differ by the mix of normal D 2 and abnormal D > 2 fractal dimensions for varied ranks r, the new types of fractal patterns and hinges for various topology (fractal dimension) at different states of health. We show that all distributions of information entropy are divided on three classes, which associated in diagnostics with a good health or dominants of autoimmune or inflammatory diseases. This classification based on switching of stability at transcritical bifurcation in homeostasis regulation. We defined many ways for homeostasis regulation, coincidences and switching patterns in branching sequences, the averages of H&ouml;lder for deviations of entropy from homeostasis at different states of health, with various saturation levels the noises of entropy at activity of all chromosomes in support regulation of homeostasis. 展开更多
关键词 Abnormal Fractals DNA ACTIVITY and Shannon Information entropy FRACTAL Patterns and Fragmentation Informational HOMEOSTASIS Saturations of CHROMOSOMAL Correlations multi-scale FRACTAL NETWORKS of Shannon entropy
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Relic Entropy Growth and Initial Big Bang Conditions, as a Subset of Quantum Information
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作者 Andrew W. Beckwith 《Journal of High Energy Physics, Gravitation and Cosmology》 2016年第3期392-411,共20页
This paper shows how increased entropy values from an initially low big bang level can be measured experimentally by counting relic gravitons. Furthermore the physical mechanism of this entropy increase is explained v... This paper shows how increased entropy values from an initially low big bang level can be measured experimentally by counting relic gravitons. Furthermore the physical mechanism of this entropy increase is explained via analogies with early-universe phase transitions. The role of Ng’s revised infinite quantum statistics in the physics of gravitational wave detection is acknowledged. Ng’s infinite quantum statistics can be used to show that is a starting point to the increasing net universe cosmological entropy. Finally, in a nod to similarities with zero point energy (ZPE) analysis, it is important to note that the resulting in fact is much lower, allowing for evaluating initial graviton production as an emergent field phenomena, which may be similar to how ZPE states can be used to extract energy from a vacuum if entropy is not maximized. The rapid increase in entropy so alluded to without near sudden increases to 10<sup>88</sup> may be enough to allow successful modeling of relic graviton production for entropy in a manner similar to zero point energy (ZPE) energy extraction from a vacuum state. This entropy count is akin to quantum information models used to tell how much “information” may be stored in initial conditions, and transferred from a prior to the present 展开更多
关键词 entropy Cosmic singularity Zero Point Energy (ZPE) Emergent Fields GRAVITONS Vacuum States Quantum Information States Anti de Sitter Correspondence with Conformal Field Theory (Ads/CFT)
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石油行业图像数据高效安全传输方法 被引量:1
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作者 汤明 邹露 +3 位作者 何世明 谢玉森 周越淼 陈春钱 《深圳大学学报(理工版)》 北大核心 2025年第2期172-182,I0004-I0006,共14页
为解决石油行业大数据高效安全传输难题,将图像转化为三通道矩阵数据并对矩阵进行奇异值分解,综合考虑Laplace算子、灰度方差函数、离散余弦变换系数、图像相关系数、熵函数、图像结构相似度和图像信噪比等7个评价因素,利用熵权逼近理... 为解决石油行业大数据高效安全传输难题,将图像转化为三通道矩阵数据并对矩阵进行奇异值分解,综合考虑Laplace算子、灰度方差函数、离散余弦变换系数、图像相关系数、熵函数、图像结构相似度和图像信噪比等7个评价因素,利用熵权逼近理想解排序(technique for order preference by similarity to an ideal solution,TOPSIS)法对分解后的奇异值进行优选,在确保数据真实性的前提下用少量奇异值表征原始图像,进行图像压缩,降低数据大小,提高传输效率;提出多通道猫脸分割加密方法,分别对每个颜色通道的图像进行随机分割、随机加密和随机排序,解决了传统猫脸加密算法颜色通道线性相关度高,整体置乱度低的问题.结果表明:改进奇异值压缩技术在保证图像清晰的情况下仅利用15%的奇异值数据完成对图像的压缩,最大图像压缩比可达4.43,平均压缩后所占用的存储空间仅为原空间的26.29%,数据传输控制协议通信平均传输效率提高86.39%.在加密图像达到0相关的前提下,多通道猫脸分割加密算法加密图像在像素点处三通道颜色值完全不同,新方法颜色通道相关系数分别为0.20、0.22和0.25,对比传统猫脸加密方法,分别降低0.78、0.75和0.71.新方法加密效果好、难破解,可为石油行业数字化转型提供理论和技术支撑. 展开更多
关键词 石油天然气工业 图像数据 改进奇异值压缩 猫脸变换 熵权TOPSIS法 传输控制协议 数据安全
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基于改进SVD-HPO-VMD电缆局部放电去噪方法
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作者 马星河 李凯濛 +1 位作者 赵军营 刘鹏 《广东电力》 北大核心 2025年第4期89-100,共12页
对局部放电(partial discharge,PD)的检测是获知高压电缆绝缘状态的主要手段之一,但现场对PD信号的检测易受到噪声的干扰,从而影响对信号检测的准确度。为此,提出一种采用猎人猎物优化算法(hunter-prey optimization algorithm,HPO)优... 对局部放电(partial discharge,PD)的检测是获知高压电缆绝缘状态的主要手段之一,但现场对PD信号的检测易受到噪声的干扰,从而影响对信号检测的准确度。为此,提出一种采用猎人猎物优化算法(hunter-prey optimization algorithm,HPO)优化变分模态分解(variational mode decomposition,VMD),再采用改进奇异值分解(singular value decomposition,SVD)对PD信号进行降噪的方法。首先,对含噪PD信号进行傅里叶变换,在傅里叶变换功率谱中运用差分变换及设定阈值的方法去筛选周期性窄带干扰奇异值;然后,通过HPO优化VMD的参数选择,分解出K个本征模态函数(intrinsic mode function,IMF),利用模糊散布熵(fuzzy dispersion entropy,FuzzyDispEn)确定IMF的性质,从而区分有效分量和噪声分量,对分类后的噪声主导分量通过改进小波阈值方法进行去噪;最后,将信号进行重构,通过仿真和实验计算去噪后信号的信噪比、归一化相关系数以及均方误差,并与传统方法进行比对,证明提出的方法能够有效去除PD信号中的噪声分量,能够运用到供电系统中。 展开更多
关键词 局部放电 变分模态分解 奇异值分解 猎人猎物优化算法 模糊散布熵
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截止频率改进的CEEMDAN-SVD高压并联电抗器声信号协同去噪方法
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作者 王果 贺建山 +2 位作者 闵永智 何怡刚 郝大宇 《电机与控制学报》 北大核心 2025年第10期159-173,共15页
针对高压并联电抗器在现场声纹监测中易受各类复杂噪声干扰的问题,提出一种结合改进自适应噪声完备集合经验模态分解(CEEMDAN)与奇异值分解(SVD)的电抗器声信号协同降噪方法。首先,利用考虑电抗器噪声声纹特性的最小下限截止频率对CEEM... 针对高压并联电抗器在现场声纹监测中易受各类复杂噪声干扰的问题,提出一种结合改进自适应噪声完备集合经验模态分解(CEEMDAN)与奇异值分解(SVD)的电抗器声信号协同降噪方法。首先,利用考虑电抗器噪声声纹特性的最小下限截止频率对CEEMDAN的筛分停止条件进行改进,基于改进CEEMDAN分解电抗器染噪声信号。其次,通过计算分解后各阶分量的样本熵优选信号主导分量,去除噪声主导分量。然后对各信号主导分量进行SVD分解,以彻底压制边界分量处的剩余噪声和所有底噪,最后重构各阶分量得到纯净声信号。模拟实验和现场噪声实验表明,改进CEEMDAN-SVD协同去噪方法与维纳滤波、小波包降噪、VMD等方法或单一降噪算法相比去噪效果最优,在电抗器正常和异常状态下均能实现声信号的有效去噪,并能够完整保留50 Hz倍频特征,为后续声纹状态辨识提供可靠的数据基础。 展开更多
关键词 高压并联电抗器 声信号去噪 自适应完备集合经验模态分解 奇异值分解 截止频率 样本熵
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基于OOA-VMD-SVD的结构振动信号降噪研究
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作者 赵锐 卢西旺 岳子翔 《中国测试》 北大核心 2025年第10期148-159,共12页
为了解决建筑结构振动信号监测过程中存在的大量随机噪声问题,针对钢梁实测数据提出一种基于鱼鹰优化算法(OOA)的变分模态分解(VMD)联合奇异值分解(SVD)的新型降噪方法(OOA-VMD-SVD)。该方法首先基于仿真数据,利用鱼鹰优化算法,并结合... 为了解决建筑结构振动信号监测过程中存在的大量随机噪声问题,针对钢梁实测数据提出一种基于鱼鹰优化算法(OOA)的变分模态分解(VMD)联合奇异值分解(SVD)的新型降噪方法(OOA-VMD-SVD)。该方法首先基于仿真数据,利用鱼鹰优化算法,并结合能量熵判定机制,确定VMD分解层数K和二次惩罚因子α两个最优参数,从而有效抑制模态混叠现象;其次,利用皮尔逊系数判定机制区分有用信号分量与噪声分量,再采用SVD对有用信号分量进行降维;最后,对两次降噪保留的有用信号进行重构,得到降噪后的信号,并用钢梁实验和监测数据进行验证。仿真和钢梁实验结果表明,与小波软硬阈值法、VMD及VMD-小波降噪方法相比,OOA-VMD-SVD方法能够显著提高信噪比,对于监测数据也能更加有效地保留信号中的有用信息,为结构健康监测中的信号处理提供了一种高效、稳定的降噪方案。 展开更多
关键词 结构振动信号 变分模态分解 能量熵 奇异值分解 降噪
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基于相角差余弦值奇异熵的远海风电交流汇集线路单端量保护原理
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作者 戴志辉 韩哲宇 李杭泽 《电力系统保护与控制》 北大核心 2025年第4期1-13,共13页
海上风电柔直送出系统两侧电力电子设备均采用负序抑制控制策略。交流汇集线路故障时,两侧故障电流相角和幅值都发生较大变化,使传统工频量距离保护可靠性降低。为此,首先阐述了海上风电交流汇集系统结构,并分析负序抑制策略实现方法。... 海上风电柔直送出系统两侧电力电子设备均采用负序抑制控制策略。交流汇集线路故障时,两侧故障电流相角和幅值都发生较大变化,使传统工频量距离保护可靠性降低。为此,首先阐述了海上风电交流汇集系统结构,并分析负序抑制策略实现方法。其次,考虑电容电流分析传统距离保护适应性,并分析不同故障下相电流与其超前相电流相角差值余弦值的变化情况。在此基础上,利用Hankel矩阵反映特征量突变程度,提出一种基于相角差余弦值奇异熵的交流汇集线路单端量保护原理。最后,基于PSCAD/EMTDC搭建海上风电系统模型,分析并验证所提保护方案的有效性。结果表明,所提保护方案动作灵敏,可靠性高,能耐受20 dB噪声和100Ω过渡电阻。 展开更多
关键词 采样算法 单端量保护 奇异熵 接地故障 海上风电
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