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基于Transformer-LSTM网络的轴承寿命预测
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作者 张帆 姚德臣 +4 位作者 姚圣卓 杨建伟 王琰亮 魏明辉 胡忠硕 《振动与冲击》 EI CSCD 北大核心 2024年第6期320-328,共9页
轴承是旋转机械设备中的重要部件,由于工况、材质、加工方式等原因,轴承寿命时长相差许多。传统的并行或串行神经网络预测方式,对数据集有一定要求。因此,需要一种能够适用于不同数据长短的轴承剩余使用寿命预测网络。为此提出了一种能... 轴承是旋转机械设备中的重要部件,由于工况、材质、加工方式等原因,轴承寿命时长相差许多。传统的并行或串行神经网络预测方式,对数据集有一定要求。因此,需要一种能够适用于不同数据长短的轴承剩余使用寿命预测网络。为此提出了一种能够预测不同寿命时长的Transformer-LSTM串并行神经网络预测模型。通过将Transformer解码层进行重构,并与长短期记忆时序神经网络(long short-term memory,LSTM)网络结构融合,实现轴承寿命数据的串并行预测处理。试验结果表明Transformer-LSTM神经网络能够精准预测长、中、短不同寿命时长的轴承失效时间,具有较强的模型泛化能力,提升轴承寿命预测精度与模型的泛化能力。 展开更多
关键词 滚动轴承 轴承寿命预测 transformer神经网络 LSTM神经网络 非线性时间序列预测
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Numerical Experiments and Structural Transformation of Non-Linear Evolution in Ill-posed Systems 被引量:1
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作者 OuYang Shoucheng,Wang Liuran(Chengdu University of Information and Technology,610041,China) 《工程科学(英文版)》 2007年第3期57-63,共7页
Numerical experiments on non-linear equations of the 1st-and 3rd-order derivatives have been carried out through structural analyses in the phase space according to the numerical instability of ill-posed systems,with ... Numerical experiments on non-linear equations of the 1st-and 3rd-order derivatives have been carried out through structural analyses in the phase space according to the numerical instability of ill-posed systems,with changes of initial values and parameters,etc..The results show that the quantitative instability in an ill-posed system may reveal reversed transformation in system evolution by structural representation,and confirm A·Dauglas' theorem that "a non-linear equation does not satisfy the existence of the initial value in a linear well-posed system". 展开更多
关键词 non-linearity ILL-POSED SYSTEMS INSTABILITY of quantity reversed transformATION CURVATURE
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Double Elzaki Transform Decomposition Method for Solving Non-Linear Partial Differential Equations
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作者 Moh A. Hassan Tarig M. Elzaki 《Journal of Applied Mathematics and Physics》 2020年第8期1463-1471,共9页
In this paper, we discuss a new method employed to tackle non-linear partial differential equations, namely Double Elzaki Transform Decomposition Method (DETDM). This method is a combination of the Double ELzaki Trans... In this paper, we discuss a new method employed to tackle non-linear partial differential equations, namely Double Elzaki Transform Decomposition Method (DETDM). This method is a combination of the Double ELzaki Transform and Adomian Decomposition Method. This technique is hereafter provided and supported with necessary illustrations, together with some attached examples. The results reveal that the new method is very efficient, simple and can be applied to other non-linear problems. 展开更多
关键词 Double Elzaki transform Adomian Decomposition Method non-linear Partial Differential Equations
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A Novel Nonlinear Algorithm for Typhoon Cloud Image Enhancement
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作者 Chang-Jiang Zhang Bo Yang 《International Journal of Automation and computing》 EI 2011年第2期161-169,共9页
A novel nonlinear gray transform method is proposed to enhance the contrast of a typhoon cloud image.Generally,the typhoon cloud image obtained by a satellite cannot be directly used to make an accurate prediction of ... A novel nonlinear gray transform method is proposed to enhance the contrast of a typhoon cloud image.Generally,the typhoon cloud image obtained by a satellite cannot be directly used to make an accurate prediction of the typhoon's center or intensity because the contrast of the received typhoon cloud image may be bad.Our aim is to extrude the typhoon's eye in the typhoon cloud image.A normalized arc-tangent transformation operation is designed to enhance global contrast of the typhoon cloud image.Differential evolution algorithm is used to choose the optimal nonlinear transform parameter.Finally,geodesic activity contour model is used to extract the typhoon's eye to verify the performance of the proposed method.Experimental results show that the proposed method can efficiently enhance the global contrast of the typhoon cloud image while greatly extruding the typhoon's eye. 展开更多
关键词 TYPHOON image enhancement differential evolution algorithm non-linear transform partial differential equation.
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Nonlinear analysis of a structure loaded by a stochastic excitation
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作者 高世桥 金磊 +2 位作者 M.Kasperski 刘海鹏 李明辉 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2007年第11期1479-1485,共7页
For a non-linear system excited by a stochastic load which is expressed as a time series, a recursive method based on the Z-transform is presented: To identify the obtained response time series, a discrete wavelet tr... For a non-linear system excited by a stochastic load which is expressed as a time series, a recursive method based on the Z-transform is presented: To identify the obtained response time series, a discrete wavelet transform (DWT) technique is proposed. 展开更多
关键词 non-linear STOCHASTIC RECURSIVE wavelet transform
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Line-element based nonlinear adaptive piecewise compensating correction for LVDT sensors
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作者 王立鹏 王军政 +1 位作者 赵江波 吴江丰 《Journal of Beijing Institute of Technology》 EI CAS 2013年第4期497-503,共7页
In order to solve the linear variable differential transformer (LVDT) displacement sensor nonlinearity of overall range and extend its working range, a novel line-element based adaptively seg- menting method for pie... In order to solve the linear variable differential transformer (LVDT) displacement sensor nonlinearity of overall range and extend its working range, a novel line-element based adaptively seg- menting method for piecewise compensating correction was proposed. According to the mechanical structure of LVDT, the output equation was calculated, and then the theoretic nonlinear source of output was analyzed. By the proposed line-element adaptive segmentation method, the nonlinear output of LVDT was divided into linear and nonlinear regions with a given threshold. Then the com- pensating correction function was designed for nonlinear parts employing polynomial regression tech- nique. The simulation of LVDT validates the feasibility of proposed scheme, and the results of cali- bration and testing experiments fully prove that the proposed method has higher accuracy than the state-of-art correction algorithms. 展开更多
关键词 line element adaptively segment linear variable differential transformer (LVDT) non-linear compensation correction
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Non-Frobenius Spectrum-Transformation Method
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作者 Albert Iskhakov Vladimir Pospelov Sergey Skovpen 《Applied Mathematics》 2012年第10期1471-1479,共9页
A method allowing a desirable matrix spectrum to be constructed as an alternative to the method using matrix transformation to the Frobenius form is stated. It can be applied to implement control algorithms for techni... A method allowing a desirable matrix spectrum to be constructed as an alternative to the method using matrix transformation to the Frobenius form is stated. It can be applied to implement control algorithms for technical systems without executing the variables transformation procedures that are needed for deriving a Frobenius matrix. The method can be used for simulation of systems with different spectrums for choosing an alternative that satisfies to the distinct demands. 展开更多
关键词 MATRIX SPECTRUM Modal Control SPECTRUM transformATION FROBENIUS MATRIX linear Spectral transformATION non-Frobenius transformATION
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Time-Frequency Bandwidth Product Estimation of Sinusoidal Non-Linear Chirp Keying Scheme 被引量:1
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作者 Zhiguo Sun Xiaoyan Ning Danyang Tian 《China Communications》 SCIE CSCD 2017年第8期184-194,共11页
Sine Non-linear Chirp Keying(SNCK) is a kind of high-efficient modulation scheme, which provides a potential new beamforming method in communication and radar systems. It has been proved to have advantages in some par... Sine Non-linear Chirp Keying(SNCK) is a kind of high-efficient modulation scheme, which provides a potential new beamforming method in communication and radar systems. It has been proved to have advantages in some parameter estimation issues over conventional modulation schemes. In this paper, a novel transform termed as Discrete Sinusoidal Frequency Modulation transform(DSFMT) is proposed. Then, the DSFMT of SNCK signal is deduced and classified into three types, based on which, the time-bandwidth product is estimated by the proposed algorithm. Simulation results show that the noise has a signifi cant impact on the localization of the peak value and the time-bandwidth product can be estimated by using local ratio values when. 展开更多
关键词 非线性调频 估计问题 正弦调频 键控 频带宽 时间带宽积 乘积 调制方式
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Transformer Characteristics of Linear Motor-Transformer Apparatus
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作者 Nobuo Fujii Shuhei Kanamitsu Takeshi Mizuma 《Journal of Transportation Technologies》 2011年第4期94-101,共8页
The characteristics of linear transformer are studied analytically. The transformer is composed in one of modes of linear motor-transformer apparatus proposed for future wireless light rail vehicle (LRV). The secondar... The characteristics of linear transformer are studied analytically. The transformer is composed in one of modes of linear motor-transformer apparatus proposed for future wireless light rail vehicle (LRV). The secondary (onboard) power factor can be adjusted at any value by an onboard converter. The equivalent circuit is used to study the transferred power control. The parameters are determined by three-dimensional finite element method (FEM) analysis for one pole-pair model. Under the rated primary (input) and secondary voltage and current, which are specified for linear motor operation, the characteristics of the secondary power factor are cleared. It is also shown that the input capacitor can improve the primary power factor and decrease the input power capacity, but does not change the efficiency. This linear transformer has the efficiency of 91% and the input power factor of 0.87 when the apparatus without input capacitor is controlled at the secondary power factor of 0.4. 展开更多
关键词 linear Motor LIM linear transformER non-CONTACT POWER Collection Wireless LRV FEM Finite Element Method POWER Factor Equivalent Circuit
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The Assessment of Non-Linear Effects in Clinical Research
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作者 Ton J. Cleophas Aeilko H. Zwinderman 《Pharmacology & Pharmacy》 2012年第2期139-147,共9页
Background: Novel models for the assessment of non-linear data are being developed for the benefit of making better predictions from the data. Objective: To review traditional and modern models. Results, and Conclusio... Background: Novel models for the assessment of non-linear data are being developed for the benefit of making better predictions from the data. Objective: To review traditional and modern models. Results, and Conclusions: 1) Logit and probit transformations are often successfully used to mimic a linear model. Logistic regression, Cox regression, Poisson regression, and Markow modeling are examples of logit transformation;2) Either the x- or y-axis or both of them can be logarithmically transformed. Also Box Cox transformation equations and ACE (alternating conditional expectations) or AVAS (additive and variance stabilization for regression) packages are simple empirical methods often successful for linearly remodeling of non-linear data;3) Data that are sinusoidal, can, generally, be successfully modeled using polynomial regression or Fourier analysis;4) For exponential patterns like plasma concentration time relationships exponential modeling with or without Laplace transformations is a possibility. Spline and Loess are computationally intensive modern methods, suitable for smoothing data patterns, if the data plot leaves you with no idea of the relationship between the y- and x-values. There are no statistical tests to assess the goodness of fit of these methods, but it is always better than that of traditional models. 展开更多
关键词 non-linear Effects Clinical Research Logit/Probit transformATION Box Cox transformATION ACE/AVAS Packages Curvilinear Data SPLINE MODELING Loess MODELING
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融入上下文特征提取的非自回归神经机器翻译
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作者 赵光耀 王剑 +1 位作者 高盛祥 余正涛 《陕西理工大学学报(自然科学版)》 2024年第3期44-51,83,共9页
非自回归翻译(NAT)模型是一种消除目标句子中的顺序依赖关系的翻译模型,在推理速度上取得了显著的突破。然而该模型在翻译质量方面存在一些局限,为探究原因,主要对注意机制进行了细致而全面的初步研究,研究结果揭示了NAT模型在捕捉局部... 非自回归翻译(NAT)模型是一种消除目标句子中的顺序依赖关系的翻译模型,在推理速度上取得了显著的突破。然而该模型在翻译质量方面存在一些局限,为探究原因,主要对注意机制进行了细致而全面的初步研究,研究结果揭示了NAT模型在捕捉局部性特征方面存在明显不足。为此提出了一种通过明确引入周围词汇信息而改进NAT模型局部性能力的方法。具体而言,在编码器和解码器两个方向上引入了混合分组线性变换,以获得更具局部感知性的表示。通过在WMT14英德与WMT16英罗两个数据集上进行实验,结果表明该方法以微弱的速度代价分别提高了0.7与1.03个BLEU分数,这表明该研究方法在改善NAT模型的局部性特征提取方面具有显著的效果和潜力。 展开更多
关键词 非自回归 局部性特征 混合分组线性变换 自回归
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非线性最小二乘法在傅里叶变换红外光谱定量分析中的误差估计
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作者 李新春 刘建国 +7 位作者 徐亮 沈先春 徐寒杨 束胜全 王钰豪 金岭 邓亚颂 孙永丰 《光子学报》 EI CAS CSCD 北大核心 2024年第4期20-31,共12页
根据统计学的参数估计理论,提出在傅里叶变换红外光谱定量分析中使用非线性最小二乘法进行浓度反演的参数误差估计方法。实验中,通过光谱平均次数来控制噪声水平,以此来评估不同噪声水平下混合气体中各组分反演结果的估计误差。结果表明... 根据统计学的参数估计理论,提出在傅里叶变换红外光谱定量分析中使用非线性最小二乘法进行浓度反演的参数误差估计方法。实验中,通过光谱平均次数来控制噪声水平,以此来评估不同噪声水平下混合气体中各组分反演结果的估计误差。结果表明,对于自研抽取式傅里叶变换红外光谱仪,8次平均光谱即可满足反演误差小于3%的需求,64次平均光谱的反演结果配合估计误差可以实现对平均浓度的覆盖率达到100%。随着噪声水平的降低,仪器、环境等非噪声因素的扰动是估计误差的主要部分。该方法在优化光谱定量分析的参数配置和指导光谱仪器系统设计等诸多方面具有重要的应用前景。 展开更多
关键词 傅里叶变换红外光谱 定量分析 非线性最小二乘 多组分 误差估计
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计及振动响应的变压器绕组轴向机械强度动态评估方法研究 被引量:2
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作者 张凡 马程 +2 位作者 李秀广 朱筱瑜 汲胜昌 《中国电机工程学报》 EI CSCD 北大核心 2023年第16期6494-6504,共11页
变压器线圈在短路电动力的作用下产生强烈的轴向振动,影响线圈强度。为了深入研究线圈的短路振动特性及其对轴向强度的影响规律,该文首先建立绕组轴向的非线性振动模型,提出线圈、垫块、压板动态压缩力以及导线轴向弯曲应力的计算方法;... 变压器线圈在短路电动力的作用下产生强烈的轴向振动,影响线圈强度。为了深入研究线圈的短路振动特性及其对轴向强度的影响规律,该文首先建立绕组轴向的非线性振动模型,提出线圈、垫块、压板动态压缩力以及导线轴向弯曲应力的计算方法;然后,对一台SZ-50000/110kV变压器的动态轴向强度进行评估,并与传统的静态计算结果进行对比;最后,分析电流幅值、压紧力和固有频率对轴向强度的影响规律。研究结果表明,采用动态模型计算的线圈、垫块、压板压缩力和导线的轴向弯曲应力均大于静态计算结果。针对该文所研究的变压器,绕组二阶固有频率接近电动力频率时,线圈压缩力可增加10~25kN,压板最大应力可增加8MPa,轴向弯曲应力可分别增加5~10MPa。所提模型和计算方法对于提升变压器短路强度评估水平非常关键。 展开更多
关键词 电力变压器 外部短路 绕组机械强度 动态评估 非线性振动
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教育深化与文化产业发展非线性关系的理论机制与实证检验 被引量:2
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作者 刘杨 李春林 《山东大学学报(哲学社会科学版)》 北大核心 2023年第2期35-46,共12页
教育在推动文化产业高质量发展中发挥着重要作用,然而其影响机制始终是一个“黑箱”。通过构建包含文化产业部门的结构转型一般均衡模型,分析教育深化对文化产业发展的影响。研究表明,教育通过消费需求结构影响文化产业比重,而收入效应... 教育在推动文化产业高质量发展中发挥着重要作用,然而其影响机制始终是一个“黑箱”。通过构建包含文化产业部门的结构转型一般均衡模型,分析教育深化对文化产业发展的影响。研究表明,教育通过消费需求结构影响文化产业比重,而收入效应与价格效应是教育作用于消费需求结构的两个渠道,当收入效应为负向、价格效应为正向时,总效应随着收入水平的提高逐渐由负转正,教育水平与文化产业发展之间呈非线性关系。模型很好地解释了中国省份数据的特征事实。进一步,利用CHFS数据从微观层面对理论模型结论进行了定量估计和实证检验,在考虑内生性问题之后,两者间的非线性关系依然稳健。利用门槛模型的估计更细致地刻画了这一非线性关系,发现收入带来的调节效应当其跨过双重门槛值后会产生较大的跳跃。 展开更多
关键词 教育深化 文化产业 结构转型模型 非线性关系
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Generalized non-linear strength theory and transformed stress space 被引量:60
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作者 YAO Yangping LU Dechun +1 位作者 ZHOU Annan ZOU Bo 《Science China(Technological Sciences)》 SCIE EI CAS 2004年第6期691-709,共19页
Based on the test data of frictional materials and previous research achievements in this field, a generalized non-linear strength theory (GNST) is proposed. It describes non-linear strength properties on the π-plane... Based on the test data of frictional materials and previous research achievements in this field, a generalized non-linear strength theory (GNST) is proposed. It describes non-linear strength properties on the π-plane and the meridian plane using a unified formula, and it includes almost all the present non-linear strength theories, which can be used in just one material. The shape of failure function of the GNST is a smooth curve between the SMP criterion and the Mises criterion on the π-plane, and an exponential curve on the meridian plane. Through the transformed stress space based on the GNST, the combination of the GNST and various constitutive models using p and q as stress parameters can be realized simply and rationally in three-dimensional stress state. 展开更多
关键词 概括非线性的强度理论(GNST ) 转变应力 组成的模型 申请
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非理想条件下MMC-PET非线性复合控制策略 被引量:2
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作者 程启明 孙英豪 程尹曼 《南方电网技术》 CSCD 北大核心 2023年第10期1-12,共12页
由于模块化多电平变流器(modular multilevel converter,MMC)电力电子变压器(power electronic transformer,PET)使用传统的控制策略难以保证系统运行时的动态性能,在电网处于不平衡时使得控制难度进一步增加。为了提高系统的动态性能,... 由于模块化多电平变流器(modular multilevel converter,MMC)电力电子变压器(power electronic transformer,PET)使用传统的控制策略难以保证系统运行时的动态性能,在电网处于不平衡时使得控制难度进一步增加。为了提高系统的动态性能,提出了一种非线性的反馈线性化滑模复合控制策略。该复合控制策略将反馈线性化控制(feedback linearization control,FLC)和滑模控制(sliding mode control,SMC)的优势结合在一起实现优势互补。首先,建立了MMC-PET整体仿真模型;其次,通过数学模型建立反馈线性化滑模控制的控制模型;最后,利用仿真与实验平台进行仿真对比实验,将所提复合控制策略与单一的反馈线性化控制、滑模控制以及常用的PI控制作了仿真对比,以验证所提控制策略可以在外部扰动时具有良好的动态性能和较好的鲁棒性等优势。 展开更多
关键词 模块化多电平换流器 电力电子变压器 非理想条件 反馈线性化滑模控制 非线性复合控制
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基于非线性小波变换阈值法的大坝表面变形监测分析
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作者 次边 任志明 《吉林水利》 2023年第2期25-29,共5页
为了实现对大坝坝体GNSS原始监测数据中高斯噪声、白噪声等异常特性进行有效去噪,同时要求保留异常信号中的有效信息,基于小波变换分析理论,应用非线性小波变换阈值法对大坝坝体的GNSS原始监测数据进行去噪处理。结果表明,该方法能够有... 为了实现对大坝坝体GNSS原始监测数据中高斯噪声、白噪声等异常特性进行有效去噪,同时要求保留异常信号中的有效信息,基于小波变换分析理论,应用非线性小波变换阈值法对大坝坝体的GNSS原始监测数据进行去噪处理。结果表明,该方法能够有效剔除GNSS原始监测数据中不同类型的噪声点,明确了大坝坝体外部变形与库水位的相关性关系,分析了运行期内大坝坝体外部变形相对值分布状况,揭示了大坝坝体变形的周期性、趋势性等特征,为坝体变形监测的设计、变形趋势的观测与预测等提供参考。 展开更多
关键词 非线性小波变换阈值法 水利工程 GNSS技术 外部变形监测
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基于BiEWT算法和谱估计的非接触式心率测量研究
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作者 伊勋鹏 范赐恩 +1 位作者 张浩楠 王轶博 《电子设计工程》 2023年第14期107-112,共6页
传统非接触式心率测量采用快速傅里叶变换和峰值检测方法,存在易受环境噪声影响、测量结果波动较大、精度较低的问题。因此,提出一种二重经验小波变换(Binary Empirical Wavelet Trans⁃form,BiEWT)和功率谱估计(Power Spectrum Estimati... 传统非接触式心率测量采用快速傅里叶变换和峰值检测方法,存在易受环境噪声影响、测量结果波动较大、精度较低的问题。因此,提出一种二重经验小波变换(Binary Empirical Wavelet Trans⁃form,BiEWT)和功率谱估计(Power Spectrum Estimation,PSE)相结合的非接触毫米波雷达心率测量方法。BiEWT算法融合了自适应分解方法和引入先验知识的经验小波分解方法的优势。通过R-EWT提取去除与噪声相关的多尺度分析(Multiresolution Analysis,MRA)分量,并引入心率频率先验知识进行频点筛选。通过F-EWT进一步抑制残留噪声,重构出心跳信号。利用功率谱估计方法,计算被测人的心率。实验结果表明,该方法比单次高模数的EWT算法,注意力更集中于心率频率区间。比FFT+PD算法MAPE平均下降了1.74%,比WNR+PSE算法MAPE平均下降了1.18%。 展开更多
关键词 非接触式心率测量 经验小波变换 谱估计 线性调频连续波雷达
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一个(2+1)维KdV方程的自-BT和多重孤立波解 被引量:16
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作者 李晓燕 杨德五 +2 位作者 李向正 李保安 王明亮 《河南科技大学学报(自然科学版)》 CAS 2003年第3期108-110,共3页
通过引进新的位势函数,导出了一个(2+1)维KdV方程,并利用齐次平稀原则导出了该方程的自-B¨acklund变换(BT),借助BT获得了(2+1)维KdV方程的多重孤立波解。
关键词 KDV方程 自-BT 多重孤立波解 位势函数 齐次平稀原则
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一个变系数广义Fisher方程的自-BT和精确解 被引量:21
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作者 李向正 李保安 +1 位作者 王跃明 王明亮 《河南科技大学学报(自然科学版)》 CAS 2003年第3期105-107,共3页
设方程的系数满足线性相关条件,用齐次平衡原则导出了一个广义变系数Fisher方程的自-B¨acklund变换(BT)。利用BT获得了变系数广义Fisher方程的若干精确解。
关键词 变系数广义Fisher方程 自-BT 精确解 线性相关 微分方程 扩散方程
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