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基于PSD特征的FBCCA脑电信号识别方法 被引量:1
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作者 张学军 杨京儒 《科学技术与工程》 北大核心 2024年第4期1411-1417,共7页
当前基于稳态视觉诱发电位(steady-state visual evoked potential,SSVEP)的脑机接口(brain-computer interfaces,BCIs)使用的都是单一识别算法,针对不同时间长度的识别准确率较低。提出了一种基于滤波器组的典型相关分析(filter bank c... 当前基于稳态视觉诱发电位(steady-state visual evoked potential,SSVEP)的脑机接口(brain-computer interfaces,BCIs)使用的都是单一识别算法,针对不同时间长度的识别准确率较低。提出了一种基于滤波器组的典型相关分析(filter bank canonical correlation analysis,FBCCA)与功率谱密度(power spectral density,PSD)分析相结合的SSVEP识别算法,可以提高SSVEP识别的普适性与准确率。该方法使用FBCCA寻找高相似度的参考频率信号,再通过多组PSD分析来锁定最终的响应频率,完成频率识别。该方法无需经过训练就能得到较高的识别准确率。实验结果表明:在刺激时长为1 s时,该方法能达到86.61%的准确率,比PSD分析方法提升了5.44%,比典型相关性分析方法(canonical correlation analysis,CCA)提升了10.38%的准确率,比FBCCA提升了8.86%的准确率。 展开更多
关键词 脑机接口(BCI) 稳态视觉诱发电位(SSVEP) 滤波器组的典型相关分析(FBCCA) 功率谱密度(psd) 频率识别
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Life Prediction Based on Transient Dynamics Analysis of Van Semi-trailer with Air Suspension System 被引量:3
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作者 LI Liang SONG Jian HE Lin ZHANG Mengjun LI Hongzhi 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2011年第3期372-379,共8页
The early fatigue damage in the van-body of the semi-trailer is often caused by the unique mechanical characteristics and the dynamic impact of the loads.The traditional finite element method with static strength anal... The early fatigue damage in the van-body of the semi-trailer is often caused by the unique mechanical characteristics and the dynamic impact of the loads.The traditional finite element method with static strength analysis cannot support the fatigue design of van-body;thus,the dynamics analysis should be adopted for the endurance performance.The accurate dynamics model to describe the transient impacts of all kinds of uneven road and the proper system transfer functions to calculate the load transfer effects from tire to van-body are two critical factors for transient dynamics analysis.In order to evaluate the dynamic performance,the dynamics model of the trailer with the air suspension is brought forward.Then the analysis method of the power spectral density (PSD) is set up to study the transient responses of the road dynamic impacts.The transient responses transferred from axles to van-body are calculated,such as dynamic stress,dynamic RMS acceleration,and dynamic load factors.Based on the above dynamic responses,the fatigue life of van-body is predicted with the finite element analysis (FEA) method.Applying the test parameters of the trailer with air suspension,the simulation system with Matlab/Simulink is constructed to describe the dynamic responses of the impacts of the tested PSD of the vehicle axles,and then the fatigue life is predicted with FEA method.The simulated results show that the vibration level of the van-body with air suspension is reduced and the fatigue life is improved.The real vehicle tests on different roads are carried out,and the test results validate the accuracy of the simulation system.The proposed fatigue life prediction method is effective for the virtual design of auto-body. 展开更多
关键词 van-body air suspension system transient dynamics power spectral density (psd life prediction
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Analysis of Turbulence Structure in the Stirred Tank with a Deep Hollow Blade Disc Turbine by Time-resolved PIV 被引量:6
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作者 刘心洪 包雨云 +1 位作者 李志鹏 高正明 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2010年第4期588-599,共12页
The turbulence structure in the stirred tank with a deep hollow blade(semi-ellispe) disc turbine(HEDT) was investigated by using time-resolved particle image velocimetry(TRPIV) and traditional PIV.In the stirred tank,... The turbulence structure in the stirred tank with a deep hollow blade(semi-ellispe) disc turbine(HEDT) was investigated by using time-resolved particle image velocimetry(TRPIV) and traditional PIV.In the stirred tank,the turbulence generated by blade passage includes the periodic components and the random turbulent ones.Traditional PIV with angle-resolved measurement and TRPIV with wavelet analysis were both used to obtain the random turbulent kinetic energy as a comparison.The wavelet analysis method was successfully used in this work to separate the random turbulent kinetic energy.The distributions of the periodic kinetic energy and the random turbulent kinetic energy were obtained.In the impeller region,the averaged random turbulent kinetic energy was about 2.6 times of the averaged periodic one.The kinetic energies at different wavelet scales from a6 to d1 were also calculated and compared.TRPIV was used to record the sequence of instantaneous velocity in the impeller stream.The evolution of the impeller stream was observed clearly and the sequence of the vorticity field was also obtained for the identification of vortices.The slope of the energy spectrum was approximately-5/3 in high frequency representing the existence of inertial subrange and some isotropic properties in stirred tank.From the power spectral density(PSD) ,one peak existed evidently,which was located at f0(blade passage frequency) generated by the blade passage. 展开更多
关键词 stirred tank time-resolved particle image velocimetry wavelet analysis energy spectrum power spectral density turbulent kinetic energy
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AFM Analysis of TiN, TiAlN, and TiAlSiN Coatings Prepared by Cathodic Arc Ion Plating 被引量:5
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作者 王文昌 ZHANG Ling 孔德军 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2016年第5期1093-1098,共6页
The TiN, TiAlN, and TiAlSiN coatings were prepared on YT14 cutting tool surface with CAIP(cathode arc ion plating), the surface morphologies and phases were analyzed with FESEM(field emission scanning electron micr... The TiN, TiAlN, and TiAlSiN coatings were prepared on YT14 cutting tool surface with CAIP(cathode arc ion plating), the surface morphologies and phases were analyzed with FESEM(field emission scanning electron microscopy), and XRD(X-ray diffraction), respectively, and the coating parameters such as 3D surface micro-topography, grain size, surface height, hierarchy, profile height, and power spectral density, etc, were measured with AFM(atomic force microscope). The results show that the phases of TiN, TiAlN, and TiAlSiN coatings are TiN, TiN+TiAlN, TiN+Si_3N_4+TiAlN, respectively, while the surface roughness Sa of TiN, TiAlN, and TiAlSiN coatings is 75.3, 98.9, and 42.1 nm, respectively, and the roughness depth Sk is 209, 389, and 54 nm, respectively, the sequence of average grain sizes is TiAlN〉TiN〉TiAlSiN. The surface bearing index Sbi of TiN, TiAlN, and TiAlSiN coatings is 0.884, 1.01, and 0.37, respectively, and the sequence of surface bearing capability is TiAlN〉TiN〉TiAlSiN. At the lower wavelength(102-103 nm), the power spectral densities have a certain correlation, and the sequence of TiN〉TiAlN〉TiAlSiN, while the correlation is low at the higher wavelength(〉103 nm). 展开更多
关键词 TiN TiAlN and TiAlSiN coatings AFM 3D surface micro-topography height analysis power spectral density
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Nonlinear Dynamic Analysis of MPEG-4 Video Traffic
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作者 GE Fei CAO Yang WANG Yuan-ni 《Wuhan University Journal of Natural Sciences》 EI CAS 2005年第6期1019-1024,共6页
The main research motive is to analysis and to veiny the inherent nonlinear character of MPEG-4 video. The power spectral density estimation of the video trafiic describes its 1/f^β and periodic characteristics.The p... The main research motive is to analysis and to veiny the inherent nonlinear character of MPEG-4 video. The power spectral density estimation of the video trafiic describes its 1/f^β and periodic characteristics.The priraeipal compohems analysis of the reconstructed space dimension shows only several principal components can be the representation of all dimensions. The correlation dimension analysis proves its fractal characteristic. To accurately compute the largest Lyapunov exponent, the video traffic is divided into many parts.So the largest Lyapunov exponent spectrum is separately calculated using the small data sets method. The largest Lyapunov exponent spectrum shows there exists abundant nonlinear chaos in MPEG-4 video traffic. The conclusion can be made that MPEG-4 video traffic have complex nonlinear be havior and can be characterized by its power spectral density,principal components, correlation dimension and the largest Lyapunov exponent besides its common statistics. 展开更多
关键词 MPEG-4 video traffic behavior nonlinear dynamic analysis power spectral density principal components analysis correlation dimension largest Lyapunov exponent
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Radiator Vibration Fatigue Analysis
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作者 Toure Ismael Buyun Sheng 《Journal of Electronics Cooling and Thermal Control》 2017年第1期8-21,共14页
This paper is the second step of our work. The first step presents a set of parametric studies performed on automotive radiators by designing different heat exchanger models. The analysis focuses on the cooling perfor... This paper is the second step of our work. The first step presents a set of parametric studies performed on automotive radiators by designing different heat exchanger models. The analysis focuses on the cooling performance for automobile radiator by changing several dimensions of the radiator fin phase (P2.5, P2.4, P2.3, P2.2, and P2.1) as well as the importance of coolant flow lay-out on the radiator global performance [1]. The second step consists on the study of the vibration fatigue of the sample with the best heat dissipation performance we design (radiator P2.1). We use Hyper Mesh to proceed with the finite element model. Frequency response analysis is solved by using MSC. Nastran (MSC. MD. Nastran. v2010.1.3-MAGNiTUDE), fatigue durability ana-lysis by using MSC Fatigue. In this experiment, the frequency response of the unit load (the unit load is 1 g) is analyzed. Based on the analysis of the frequency response of the unit load, the fatigue life of the radiator is analyzed by the PSD (power spectral density) curve and the S-N curve. From our experiments results, we observe that the radiator we design meets the international requirements of fatigue vibration under automobile normal working condition. 展开更多
关键词 AUTOMOBILE RADIATOR RADIATOR FIN S-N and psd (power spectral density) CURVE Fatigue Durability Frequency Response
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基于ICA与PSD的ERD/ERS信号检测 被引量:6
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作者 万柏坤 周仲兴 +4 位作者 刘亚伟 程龙龙 明东 綦宏志 朱誉环 《天津大学学报》 EI CAS CSCD 北大核心 2008年第11期1383-1390,共8页
介绍一种基于独立分量分析(ICA)空间滤波结合功率谱密度(PSD)曲线分析法用于提取大脑在想象动作时产生事件相关去同步/同步(ERD/ERS)信号的方法.其检测流程为:先对想象动作诱发的脑电(EEG)信号进行ICA分解得到独立分量与相应的解混矩阵... 介绍一种基于独立分量分析(ICA)空间滤波结合功率谱密度(PSD)曲线分析法用于提取大脑在想象动作时产生事件相关去同步/同步(ERD/ERS)信号的方法.其检测流程为:先对想象动作诱发的脑电(EEG)信号进行ICA分解得到独立分量与相应的解混矩阵,再按特征频段取其主要分量得到滤波后数据,然后采用短时傅里叶变换计算相关导联EEG信号在特征时段与频段的PSD曲线,引入ERD/ERS系数作为量化指标以进行想象动作的识别.计算结果表明,上述方法能够显著增强运动想象脑电信号的ERD/ERS特征信息,且通过实际分类验证,采用该方法可以获得更高的识别正确率,较传统信息检测方法平均提高8%以上. 展开更多
关键词 脑电 想象动作 独立分量分析 功率谱密度 短时傅里叶变换 ERD/ERS系数
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PSD在超精密加工实验数据分析的应用 被引量:4
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作者 王素娟 陈新度 李克天 《实验技术与管理》 CAS 北大核心 2015年第5期75-81,共7页
功率谱密度(power spectral density,PSD)用于描述随机过程的功率随频率的分布。在超精密加工实验中,功率谱方法不仅仅用于切削力信号分析,还可以用于超精密加工表面微观形貌分析;既可以反映出不同频率在表面形貌中所占的比重,还可揭示... 功率谱密度(power spectral density,PSD)用于描述随机过程的功率随频率的分布。在超精密加工实验中,功率谱方法不仅仅用于切削力信号分析,还可以用于超精密加工表面微观形貌分析;既可以反映出不同频率在表面形貌中所占的比重,还可揭示切削参数、工件材料性能等对超精密加工表面生成的影响程度。该文使用PSD方法对超精密飞刀铣削在不同进给速度下加工不同工件材料的实验结果进行分析,结果表明,相比于表面粗糙度参数来说,PSD方法更有利于表现出工件材料对超精密加工表面的影响。 展开更多
关键词 功率谱密度 超精密加工 表面质量 切削力
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基于EMD-PSD的OLTC振动信号特征提取方法 被引量:12
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作者 徐艳 陈冰冰 +3 位作者 马宏忠 许洪华 王梁 王春宁 《电力科学与技术学报》 CAS 北大核心 2020年第5期3-10,共8页
在有载分接开关(OLTC)故障案例中机械故障占很大的比例,为确保OLTC可靠运行,提出一种基于EMD-PSD的OLTC振动信号特征提取方法。首先,模拟OLTC机械故障,采集振动信号,并根据奇异熵确定奇异值分解(SVD)的降噪阶次进行小波包-SVD降噪;其次... 在有载分接开关(OLTC)故障案例中机械故障占很大的比例,为确保OLTC可靠运行,提出一种基于EMD-PSD的OLTC振动信号特征提取方法。首先,模拟OLTC机械故障,采集振动信号,并根据奇异熵确定奇异值分解(SVD)的降噪阶次进行小波包-SVD降噪;其次,对降噪后的信号进行经验模态分解(EMD),并求其功率谱密度(PSD);最后,运用功率谱密度能量构造特征量。实验结果表明,基于奇异熵选择SVD降噪阶次,可以提高振动信号的信噪比,并且将EMD和PSD算法结合可以有效地提取OLTC故障特征。 展开更多
关键词 有载分接开关 经验模态分解 功率谱密度 奇异值分解 振动信号
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对PSDTOMA方法适用性的探究 被引量:1
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作者 刘文俊 张昱 朱彤 《噪声与振动控制》 CSCD 2020年第4期21-26,37,共7页
基于传递率的运行模态分析(TOMA)是一种新颖的模态参数识别技术,其主要特点是能够在有色激励条件下实现运行模态分析。基于功率谱密度传递率的TOMA方法(PSDTOMA)是TOMA中最具实用性的一类方法,仅根据单一荷载条件下的响应信息即可识别... 基于传递率的运行模态分析(TOMA)是一种新颖的模态参数识别技术,其主要特点是能够在有色激励条件下实现运行模态分析。基于功率谱密度传递率的TOMA方法(PSDTOMA)是TOMA中最具实用性的一类方法,仅根据单一荷载条件下的响应信息即可识别模态参数。然而,PSDTOMA技术的普遍适用性一直没有得到系统研究。从理论出发,得到了一些关于PSDTOMA方法应用局限性的结论,数值和物理试验的结果随后验证了结论的正确性。 展开更多
关键词 振动与波 运行模态分析 功率谱密度传递率 风机叶片 适用性
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PSD法在超精密加工质量评价中的应用 被引量:1
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作者 闫英 周平 +3 位作者 郭晓光 王一奇 白倩 司立坤 《实验室科学》 2018年第4期11-14,共4页
功率谱密度法(Power Spectral Density,PSD)从物理意义上来讲就是单位频率内的信号能量,用于描述随机过程的功率与频率之间的关系。PSD法可以用于分析超精密加工表面的形貌特征,也可以分析不同频率在表面形貌中的分布,从而评价加工工艺... 功率谱密度法(Power Spectral Density,PSD)从物理意义上来讲就是单位频率内的信号能量,用于描述随机过程的功率与频率之间的关系。PSD法可以用于分析超精密加工表面的形貌特征,也可以分析不同频率在表面形貌中的分布,从而评价加工工艺对超精密加工表面质量的影响。利用一维PSD的方法,评价了磨削硅片、抛光硅片、抛光铜片表面的质量,通过结果分析可知,与表面粗糙度方法相比,PSD方法可以更全面地评价被加工工件的表面质量。因此,需要在实验室教学过程中引导学生关注功率谱密度分析方法,建立功率谱密度函数与超精密加工表面质量之间的关系。 展开更多
关键词 功率谱密度 超精密加工 表面形貌 质量评价
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PSD analyzing for complicated shock signal 被引量:1
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作者 郭旻 钞红晓 +1 位作者 张鹏飞 曹馨 《Journal of Measurement Science and Instrumentation》 CAS 2013年第2期155-157,共3页
This paper presents a new idea for an a lyzing the complicated shock signal.Based on this kind of analysis,an equivale nt power spectral density(PSD) chart is drawn for vibration environmental test,which is carried to... This paper presents a new idea for an a lyzing the complicated shock signal.Based on this kind of analysis,an equivale nt power spectral density(PSD) chart is drawn for vibration environmental test,which is carried to test the vehicle loading instrument's vibration behavior.T he environment test is equivalent to the condition under which the vehicle and t he instrument is experiencing a firing period.Exactly speaking,the short time vibration during the firing period is a complicated shock event.The paper point s out the deficiency of the commonly used half sine equivalence for the shock an d vibration environment test and gives the procedure of how to draw the PSD char t through the actual acceleration data. 展开更多
关键词 environment test waveform equivalence complicated shock power spectral density(psd
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内蒙古地区强震动台站背景噪声与数据质量分析 被引量:1
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作者 安全 韩晓明 +3 位作者 包文超 翟浩 赵铁锁 赵星 《地震学报》 CSCD 北大核心 2024年第3期490-501,共12页
计算了内蒙古地区193个强震动台站2022年连续观测数据的加速度功率谱密度,通过绘制不同时空、不同加速度计、不同频段的功率谱密度和功率谱概率密度函数图及背景噪声速度均方根值分布图,评估了该区强震动台站的背景噪声变化特征,对出现... 计算了内蒙古地区193个强震动台站2022年连续观测数据的加速度功率谱密度,通过绘制不同时空、不同加速度计、不同频段的功率谱密度和功率谱概率密度函数图及背景噪声速度均方根值分布图,评估了该区强震动台站的背景噪声变化特征,对出现的功率谱密度异常进行了具体分析,并针对强震动台站数据异常检测及处理提出了相应的建议。研究结果显示:不同加速度计、不同时空强震动台站的背景噪声功率谱密度昼夜差异主要体现在1 Hz以上频段,且不同区域的昼夜差异变化较大;QA-2g型、JS-A2型和TDA-33M型三种加速度计在2 s频点的背景噪声功率谱密度随区域和三分向变化较小;从强震动台站2 s频点背景噪声的监控能得到可靠的观测数据异常,数据异常主要由加速度计零点漂移大、加速度计故障、脉冲干扰、系统参数有误造成,建议优化站点观测环境,进一步规范仪器安装、调试及JOPENS系统的参数配置和审核。 展开更多
关键词 强震动台站 功率谱密度(psd)值 速度均方根 数据质量 加速度计
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随机振动下管径壁厚对航空液压管路的疲劳寿命的影响
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作者 张凌云 王永健 +2 位作者 杨镇 何建冬 石绍秋 《热加工工艺》 北大核心 2024年第10期88-92,96,共6页
根据目前存在由流量设计的不同管径液压管路的疲劳寿命达不到要求的情况,不同管径和壁厚的航空液压导管在随机振动工况下进行疲劳寿命的影响分析。将管路模型简化处理并进行模态分析和随机振动响应分析,最后结合疲劳损伤累积理论和材料... 根据目前存在由流量设计的不同管径液压管路的疲劳寿命达不到要求的情况,不同管径和壁厚的航空液压导管在随机振动工况下进行疲劳寿命的影响分析。将管路模型简化处理并进行模态分析和随机振动响应分析,最后结合疲劳损伤累积理论和材料的S-N曲线数据得出不同管径壁厚下的疲劳寿命时间。结果表明:当管径和壁厚越大时,对疲劳寿命时间的影响越大。 展开更多
关键词 液压管路 有限元方法 随机振动 功率谱密度 疲劳寿命
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几种常用水声信号的特性研究
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作者 代伟 刘漩 《舰船电子工程》 2024年第4期173-177,共5页
水声信号是水下导航定位通信的主要信息载体,对其特性进行研究尤为重要。水声常用信号主要有连续波信号、线性调频信号和双曲线调频信号,研究了这三种常用信号的时域、频域以及功率谱波形,对它们的模糊函数、模糊度、模糊函数ξ=0和τ=... 水声信号是水下导航定位通信的主要信息载体,对其特性进行研究尤为重要。水声常用信号主要有连续波信号、线性调频信号和双曲线调频信号,研究了这三种常用信号的时域、频域以及功率谱波形,对它们的模糊函数、模糊度、模糊函数ξ=0和τ=0截面进行了计算,研究了这三种信号的自相关函数及小波时频分析,研究结果表明实验结果与理论值符合较好。 展开更多
关键词 频域 功率谱 模糊函数 自相关函数 小波时频分析
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融合多工况功率谱密度函数的工作模态分析方法 被引量:1
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作者 曾舒洪 康杰 +1 位作者 孙嘉宝 罗杰 《振动与冲击》 EI CSCD 北大核心 2024年第4期179-189,共11页
频域分解(frequency domain decomposition,FDD)方法是开展环境激励下结构工作模态分析(operational modal analysis,OMA)的常用方法。但是,现有的FDD方法存在一些不足:①无法剔除非白激励及谐波激励引起的虚假模态;②无法区分结构密集... 频域分解(frequency domain decomposition,FDD)方法是开展环境激励下结构工作模态分析(operational modal analysis,OMA)的常用方法。但是,现有的FDD方法存在一些不足:①无法剔除非白激励及谐波激励引起的虚假模态;②无法区分结构密集模态与不相关非白激励产生的虚假模态。通过研究发现功率谱密度(power spectral density,PSD)矩阵的秩是FDD方法性能的决定性因素。在此基础上,提出一种新的工作模态识别OMA方法,该方法结合了不同激励工况下的响应PSD函数矩阵,并分别对单个激励工况下的响应PSD矩阵与多工况下的增广响应PSD矩阵进行奇异值分解,通过对比单工况PSD矩阵与增广PSD矩阵在奇异值峰值处秩的变化,识别出包括密集模态在内的结构模态参数,并消除由非白激励产生的虚假模态。采用桁架结构仿真算例和广州塔的工程数据集验证所提方法的有效性。 展开更多
关键词 工作模态分析(OMA) 非白噪声激励 密集模态 功率谱密度(psd)
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Spectrum analysis of interval process model and its application in uncertain vibration analysis
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作者 LI JinWu JIANG Chao NI BingYu 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2024年第8期2549-2564,共16页
In recent years, the authors have extended the traditional interval method into the time dimension to develop a new mathematical tool called the “interval process model” for quantifying time-varying or dynamic uncer... In recent years, the authors have extended the traditional interval method into the time dimension to develop a new mathematical tool called the “interval process model” for quantifying time-varying or dynamic uncertainties. This model employs upper and lower bounds instead of precise probability distributions to quantify uncertainty in a parameter at any given time point. It is anticipated to complement the conventional stochastic process model in the coming years owing to its relatively low dependence on experimental samples and ease of understanding for engineers. Building on our previous work, this paper proposes a spectrum analysis method to describe the frequency domain characteristics of an interval process, further strengthening the theoretical foundation of the interval process model and enhancing its applicability for complex engineering problems. In this approach, we first define the zero midpoint function interval process and its auto/cross-power spectral density(PSD) functions. We also deduce the relationship between the auto-PSD function and the auto-covariance function of the stationary zero midpoint function interval process. Next, the auto/cross-PSD function matrices of a general interval process are defined, followed by the introduction of the concepts of PSD function matrix and cross-PSD function matrix for interval process vectors. The spectrum analysis method is then applied to random vibration problems, leading to the creation of a spectrum-analysis-based interval vibration analysis method that determines the PSD function for the system displacement response under stationary interval process excitations. Finally, the effectiveness of the formulated spectrum-analysis-based interval vibration analysis approach is verified through two numerical examples. 展开更多
关键词 interval process spectrum analysis power spectral density(psd) time-varying uncertainty uncertain vibration analysis
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Contrastive Analysis of General and Special Forced Oscillations of Power Systems 被引量:4
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作者 Yongfei Liu Ping Ju +2 位作者 Jun Chen Yiming Zhang Yiping Yu 《CSEE Journal of Power and Energy Systems》 SCIE 2015年第1期61-68,共8页
With the continuous incorporation of renewable energy and new loads into the electric power grid,random factors that induce general forced oscillations(GFOs)gradually become risks that affect the power system's se... With the continuous incorporation of renewable energy and new loads into the electric power grid,random factors that induce general forced oscillations(GFOs)gradually become risks that affect the power system's security and stability.T his research conducts a comparative analysis of the generation mechanisms of GFOs versus the traditional special forced oscillations(SFOs),specifically,from the perspective of frequency domain.Similarities and differences in en-oscillating conditions,occurrence probabilities,and the influencing factors of GFO and SFO are compared to better understand and recognize the GFO theory and the response characteristics of the power system under random excitations.A series of simulations in the lO-generator,39-bus New England Test System is carried out to verify the analysis. 展开更多
关键词 Forced oscillations modal analysis power spectral density(psd) power system random excitations
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基于响应谱传递比估计误差的结构模态参数识别精度分析
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作者 孙倩 颜王吉 任伟新 《湖南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第7期72-82,共11页
为了研究响应谱估计误差及其传递对振动响应功率谱密度传递比(Power Spectrum Density Transmissibility,PSDT)估计的影响,基于摄动理论和统计矩定义,推导了两个变量比例函数的均值和方差近似表达式;将响应谱估计统计矩代入,可以推导出... 为了研究响应谱估计误差及其传递对振动响应功率谱密度传递比(Power Spectrum Density Transmissibility,PSDT)估计的影响,基于摄动理论和统计矩定义,推导了两个变量比例函数的均值和方差近似表达式;将响应谱估计统计矩代入,可以推导出由响应相干函数、谱估计中信号平均分段数,近似表征的PSDT估计幅值的均值和方差解析公式.基于此,揭示了共振频率处PSDT估计幅值误差规律,并实现了模态振型幅值的精度度量.研究发现,共振频率处PSDT幅值方差存在极小值,且变异系数小于相关响应谱.通过数值框架数据验证了文中误差公式的准确性.此外,还研究了参考响应的选择、响应时长、窗函数类型对PSDT和模态振型估计的影响.结果表明,以PSDT两组响应作为参考响应,能得到较好PSDT和模态分析结果;同时模态振型估计标准差随测试数据时长的增加,也随之降低至一定水平. 展开更多
关键词 频谱误差 响应功率谱传递比 模态识别 误差分析 摄动法
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波前功率谱密度函数评价方法探讨 被引量:6
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作者 任寰 卓志云 +4 位作者 蒋晓东 彭净 叶琳 黄祖鑫 唐灿 《强激光与粒子束》 EI CAS CSCD 北大核心 2002年第2期279-282,共4页
波前功率谱密度 PSD( Power Spectral Density)能定量给出波前畸变的空间频率分布、限定波纹度和粗糙度指标 ,全面反映 ICF驱动器对高功率激光光学元件加工质量的特殊要求。给出了波前功率谱密度 PSD的定义及计算方法 ,并使用大口径相... 波前功率谱密度 PSD( Power Spectral Density)能定量给出波前畸变的空间频率分布、限定波纹度和粗糙度指标 ,全面反映 ICF驱动器对高功率激光光学元件加工质量的特殊要求。给出了波前功率谱密度 PSD的定义及计算方法 ,并使用大口径相移干涉仪作为波前检测仪器 ,对光学磷酸盐钕玻璃透射波前进行了测试实验 ,获得波前一维 PSD分布 ,证实功率谱密度为高功率激光光学元件波前参数的一种有效表征方式。同时 ,还对 PSD与均方根 RMS之间的关系进行了初步的讨论。 展开更多
关键词 高功率激光驱动器 光元件 波前功率谱密度 psd ICF 惯性约束聚变 函数评价法
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