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Fractional Envelope Analysis for Rolling Element Bearing Weak Fault Feature Extraction

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IEEE/CAA Journal of Automatica Sinica 2017年第2期4卷 353-360页

作者： Jianhong Wang liyan qiao Yongqiang Ye YangQuan Chen School of Science Nantong University School of Engineering University of California IEEE College of Automation Engineering Nanjing University of Aeronautics and Astronautics

The bearing weak fault feature extraction is crucial to mechanical fault diagnosis and machine condition monitoring. Envelope analysis based on Hilbert transform has been widely used in bearing fault feature extraction. A generalization of the Hilbert transform, the fractional Hilbert transform is defined in the frequency domain, it is based upon the modification of spatial filter with a fractional parameter, and it can be used to construct a new kind of fractional analytic signal. By performing spectrum analysis on the fractional envelope signal, the fractional envelope spectrum can be obtained. When weak faults occur in a bearing, some of the characteristic frequencies will clearly appear in the fractional envelope spectrum. These characteristic frequencies can be used for bearing weak fault feature extraction. The effectiveness of the proposed method is verified through simulation signal and experiment data. © 2017 Chinese Association of Automation.

关键词： Bearings (machine parts) Condition monitoring Extraction Fault detection Feature extraction Frequency domain analysis Hilbert spaces Mathematical transformations Spectrum analysis

A Computer-Aided System for Ocular Myasthenia Gravis Diagnosis

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Tsinghua Science and Technology 2021年第5期26卷 749-758页

作者： Guanjie Liu Yan Wei Yunshen Xie Jianqiang Li liyan qiao Ji-jiang Yang the Faculty of Information Technology Beijing University of TechnologyBeijing 100124China the Neurology Department The Second Affiliated Hospital of Tsinghua UniversityBeijing 100040China the Department of Automation Tsinghua UniversityBeijing 100084China

The current mode of clinical aided diagnosis of Ocular Myasthenia Gravis(OMG)is time-consuming and laborious,and it lacks quantitative *** aided diagnostic system for OMG is proposed to solve this *** values calculated by the system include three clinical indicators:eyelid distance,sclera distance,and palpebra superior fatigability test *** the first two indicators,the semantic segmentation method was used to extract the pathological features of the patient's eye image and a semantic segmentation model was *** patient eye image was divided into three regions:iris,sclera,and *** indicators were calculated based on the position of the pixels in the segmentation *** the last indicator,a calculation method based on the Eyelid Aspect Ratio(EAR)is proposed;this method can better reflect the change of eyelid distance over *** system was evaluated based on the collected patient *** results show that the segmentation model achieves a mean Intersection-Over-Union(mIoU)value of 86.05%.The paired-sample T-test was used to compare the results obtained by the system and doctors,and the p values were all greater than ***,the system can reduce the cost of clinical diagnosis and has high application value.

关键词： ocular myasthenia gravis computer-aided system semantic segmentation eyelid aspect ratio

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异常值干扰下的加权中值截取相位检索算法

宇航总体技术 2024年第3期8卷 44-49页

作者：李晓东刘冠男付宁乔立岩哈尔滨工业大学电子与信息工程学院哈尔滨150001 北京宇航系统工程研究所北京100076

在航天领域的许多测量场景中,信号的相位信息容易遭到破坏。本文旨在解决有异常值干扰的相位检索问题。中值可以对抗异常值,故常作为正则化标准截取无相测量值,这会导致可用测量值的减少,从而提高测量复杂度。为克服这一难点,进行加权处... 详细信息

在航天领域的许多测量场景中,信号的相位信息容易遭到破坏。本文旨在解决有异常值干扰的相位检索问题。中值可以对抗异常值,故常作为正则化标准截取无相测量值,这会导致可用测量值的减少,从而提高测量复杂度。为克服这一难点,进行加权处理,提出了加权中值截取算法,利用可以表征指向原信号概率的权值进一步挖掘了未被截取测量值的可用信息,与同类算法相比,在测量复杂度和对抗异常值干扰方面更为优越。

关键词：相位检索异常值中值截取

Cell-based therapy in Alzheimer's disease: Current knowledge and perspective

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Translational Neuroscience and Clinics 2016年第1期2卷 50-58页

作者： liyan qiao Hongyun Huang Lin Chen Department of Neurology Tsinghua University Yuquan Hospital Institute of Neurorestoratology General Hospital of Armed Police Forces Beijing Hongtianji Neuroscience Academy Lingxiu Building Department of Neurosurgery Tsinghua University Yuquan Hospital

Alzheimer’s disease(AD)is the most prevalent type of dementia,and its neuropathology is characterized by the deposition of insolubleβ‐amyloid(Aβ)peptides,intracellular neurofibrillary tangles,amyloid angiopathy,age‐related brain atrophy,synaptic pathology,white matter rarefaction,granulovacuolar degeneration,neuron loss,and *** much is known about the neurobiology of AD,very few conventional therapies are available to arrest or slow the *** is an urgent need for novel therapeutic approaches for *** subjects have significantly fewer viable precursor cells in the hippocampus compared with age‐matched healthy control ***,the viable precursor cells that remain in AD and age‐matched healthy control brain specimens can be induced to *** facilitate or mimic the natural compensatory effect in AD,cell therapy,including endogenous and exogenous stem cells,has been considered in *** this review,we focus on the history and development of cell therapy in AD,and consider the role of cell therapy as a potential treatment for AD.

关键词： Alzheimer’s disease cell therapy stem cells neurogenesis

Parameter Estimation of Multi-component Chirp Signal Based on Differential Evolution

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Instrumentation 2017年第2期4卷 34-43页

作者： ZHAO Haoran MENG Fankuo qiao liyan Department of Automatic Test and Control Harbin Institute of Technology

Chirp signals show energy aggregation in the fractional Fourier domain(FrFD) w hich can be used to estimate the parameter of the signals. In this paper,a parameter estimation method for multi-component chirp signal w hich corrupted by w hite Gaussian noise is proposed based on the discrete fractional Fourier transform(DFrFT) and the differential evolution( DE) algorithm. The proposed algorithm uses the DE algorithm instead of the conventional fine search algorithm to detect the peak of the signals in the FrFD. The paper simulated the influence of the noise and the resolution of the proposed algorithm. The results of the simulation show the proposed method does not only improve the estimation accuracy of the peak coordinate,but also reduces time consuming.

关键词： Chirp Signal Fractional Fourier Transform Parameter Estimation Differential Evolution

移动互联网视域下移动图书馆数字资源版权管理探究

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图书馆工作与研究 2021年第7期 18-24页

作者：乔丽彦南阳市图书馆

移动图书馆对数字版权资源的利用呈现出组织碎片化、来源多元化和传播广域化等特征。在移动服务模式下,图书馆无论是对自有馆藏资源,还是对第三方资源,抑或对用户生成资源的组织和传播都存在直接侵权,或者间接侵权与责任承担等法律问题... 详细信息

移动图书馆对数字版权资源的利用呈现出组织碎片化、来源多元化和传播广域化等特征。在移动服务模式下,图书馆无论是对自有馆藏资源,还是对第三方资源,抑或对用户生成资源的组织和传播都存在直接侵权,或者间接侵权与责任承担等法律问题。图书馆防范和化解移动服务的版权风险,一方面,要严格遵循版权限制与例外制度和"通知—删除"程序等免责规范,不触碰"红旗标准"的底线,积极完善综合性版权管理对策;另一方面,第三方权利人和用户要增强版权保护意识和能力,为移动图书馆提供无权利瑕疵的版权资源。同时要健全版权立法,为移动图书馆发展提供宽松的法律条件,政府还要加大对侵权违法行为的查处力度,并对图书馆版权管理工作进行经常化的监督、指导。

关键词：图书馆移动互联网移动图书馆版权管理

基于频域时延-多普勒二维聚焦的欠采样雷达信号参数估方法

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电子与信息学报 2021年第11期43卷 3228-3236页

作者：尉志良付宁乔立岩哈尔滨工业大学电子与信息工程学院自动化测试与控制研究所哈尔滨150001

针对欠采样脉冲多普勒雷达信号参数估计中已有方法抗噪性差、顺序参数估计方法中后续参数估计受前面参数估计精度影响严重等问题,该文提出一种基于有限新息率(Finite Rate of Innovation,FRI)采样的频域时延-多普勒2维聚焦(FD2TF)算法... 详细信息

针对欠采样脉冲多普勒雷达信号参数估计中已有方法抗噪性差、顺序参数估计方法中后续参数估计受前面参数估计精度影响严重等问题,该文提出一种基于有限新息率(Finite Rate of Innovation,FRI)采样的频域时延-多普勒2维聚焦(FD2TF)算法。在该算法中,利用FRI采样结构能够以低于奈奎斯特采样频率的速率获得信号的一系列傅里叶系数,通过频域2维聚焦过程能够同时估计时延和多普勒参数,避免了参数顺序估计中误差累积的问题,理论分析证明了该算法能够大幅提升采样信号的信噪比,提高算法抗噪性和鲁棒性。在2维聚焦算法的基础上该文还提出了基于逆傅里叶变换的2维聚焦简化算法,在提高参数估计网格密度的同时,大大减低了2维聚焦算法的计算量。仿真和对比实验结果证明了该方法的有效性和良好的抗噪性。

关键词：脉冲多普勒雷达有限新息率采样欠采样参数估计

A visible-light-assisted Pd/TiO_(2)gas sensor with carbon nanotubes electrodes for trace formaldehyde detection

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Rare Metals 2024年第1期43卷 257-266页

作者： Can Liu qiao-qiao Zou Bin Liu Yong Zhang School of Physics and Optoelectronics Xiangtan UniversityXiangtan 411105China Hunan Institute of Advanced Sensing and Information Technology Xiangtan UniversityXiangtan 411105China School of Materials Science and Engineering Xiangtan UniversityXiangtan 411105China

Owing to the ppb-level detection standard toward the toxic and harmful gas,the detection of trace gases has become an important subject in the field of indoor environment ***,the traditional resistive gas sensors hardly meet the requirement due to the weak signal generated by trace gas molecules that are difficult to ***,a visible-light-assisted Pd/TiO_(2)gas sensor is proposed to endow the effective detection of trace formaldehyde(HCHO)gas without heating *** from the enhanced photocatalytic properties of TiO_(2)by Pd decoration,the visible-light-assisted Pd/TiO_(2)gas sensor can detect the HCHO gas as low as80×10^(–9)at room *** successful preparation of nanoscale TiO_(2)sensing layer is facilitated by the ultrathin carbon nanotube interdigital electrode in the gas sensor,which avoids the discontinuity of the sensing layer caused by the excessive thickness of the traditional metal *** addition,the whole preparation process of the Pd/TiO_(2)gas sensor with carbon nanotube electrodes is compatible with mainstream CMOS fabrication technology,which is expected to realize the batch fabrication and micro-integrated application of gas *** is expected that our work can provide a new strategy for the batch preparation of high-performance trace HCHO gas sensors and their future applications in portable electronic devices such as smartphones.

关键词： Visible-light-assisted gas sensor Pd/TiO_(2) Trace HCHO detection Carbon nanotubes electrodes

Reconfigurable Test Software

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Reconfigurable Test Software