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Real time remaining useful life prediction based on nonlinear Wiener based degradation processes with measurement errors 被引量:22
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作者 唐圣金 郭晓松 +3 位作者 于传强 周志杰 周召发 张邦成 《Journal of Central South University》 SCIE EI CAS 2014年第12期4509-4517,共9页
Real time remaining useful life(RUL) prediction based on condition monitoring is an essential part in condition based maintenance(CBM). In the current methods about the real time RUL prediction of the nonlinear degrad... Real time remaining useful life(RUL) prediction based on condition monitoring is an essential part in condition based maintenance(CBM). In the current methods about the real time RUL prediction of the nonlinear degradation process, the measurement error is not considered and forecasting uncertainty is large. Therefore, an approximate analytical RUL distribution in a closed-form of a nonlinear Wiener based degradation process with measurement errors was proposed. The maximum likelihood estimation approach was used to estimate the unknown fixed parameters in the proposed model. When the newly observed data are available, the random parameter is updated by the Bayesian method to make the estimation adapt to the item's individual characteristic and reduce the uncertainty of the estimation. The simulation results show that considering measurement errors in the degradation process can significantly improve the accuracy of real time RUL prediction. 展开更多
关键词 remaining useful life Wiener based degradation process measurement error nonlinear maximum likelihood estimation Bayesian method
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Current measurement method based on magneto-optic rotation effect
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作者 SHUI Huasheng RONG Yufei +1 位作者 JIANG Chunlei DONG Taiji 《Optoelectronics Letters》 EI 2023年第9期563-569,共7页
Aiming at the approximate measurement of magnetic rotation angle in optical current sensor based on light intensity detection mode,this paper proposes a current measurement method based on triangular constant transfor... Aiming at the approximate measurement of magnetic rotation angle in optical current sensor based on light intensity detection mode,this paper proposes a current measurement method based on triangular constant transformation to reconstruct magnetic rotation angle,so as to avoid the large current measurement error caused by the approximate measurement of the magnetic rotation angle.By extracting the direct current(DC)component and the alternating current(AC)component of the light intensity signal detected by the photoelectric detector(PD),the sine signal containing the magnetic rotation angle is directly obtained by dividing the two components,and then the triangular identity transformation method is used to linearly demodulate the magnetic rotation angle and reconstruct the current waveform.The experimental results show that the relative error of current measurement does not exceed 1.40%in the current range of 0.05—0.50 A,which is less than the approximate linear measurement(ALM)method,and the magnetic rotation angle and the current have a good linear relationship. 展开更多
关键词 Current measurement method based on magneto-optic rotation effect
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Absolute surface form measurement of flat optics based on oblique incidence method 被引量:1
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作者 Longbo Xu Shijie Liu +2 位作者 Rihong Zhu You Zhou Jie Chen 《Chinese Optics Letters》 SCIE EI CAS CSCD 2018年第10期30-33,共4页
In this Letter, a test method based on oblique incidence is practically implemented in the interferometric measurement process. Three sets of wavefront data are achieved through cavity interference measurement with a ... In this Letter, a test method based on oblique incidence is practically implemented in the interferometric measurement process. Three sets of wavefront data are achieved through cavity interference measurement with a Fizeau interferometer and one oblique incidence measurement. An iterative algorithm is applied to retrieve the absolute surface shape of the test flat. By adding two sets of measurements, the absolute surface error of the interferometer's reference flat can be obtained. The new method can not only calibrate the reference flat error of interferometer, but also provide the absolute measurement method for high precision optical components applied in high power laser systems. 展开更多
关键词 Absolute surface form measurement of flat optics based on oblique incidence method
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An objective method for color vision deficiencies measurement based on visual evoked potential
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作者 熊凯 侯民贤 叶关荣 《Chinese Optics Letters》 SCIE EI CAS CSCD 2005年第7期432-434,共3页
The equi-luminance of color stimulus in normal subjects is characterized by L-cone and M-cone activation in retina. For the protanopes and deuternopes, only the activations of one relevant remaining cone type should b... The equi-luminance of color stimulus in normal subjects is characterized by L-cone and M-cone activation in retina. For the protanopes and deuternopes, only the activations of one relevant remaining cone type should be considered. The equi-luminance turning curve was established for the recorded visual evoked potentials (VEPs) of the luminance changes of the red and green color stimulus, and the position of the equi-luminance was used to define the kind and degree of color vision deficiencies. In the test of 47 volunteers we got the VEP traces and the equi-luminance turning curves, which was in accordance with the judgment by the pseudoisochromatic plate used in clinic. The method fulfills the objective and quantitative requirements in color vision deficiencies test. 展开更多
关键词 An objective method for color vision deficiencies measurement based on visual evoked potential VEP
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Measuring method for micro-diameter based on structured-light vision technology 被引量:7
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作者 刘斌 王鹏 +1 位作者 曾勇 孙长库 《Chinese Optics Letters》 SCIE EI CAS CSCD 2010年第7期666-669,共4页
Based on structured-light vision measurement technology, we study a measuring method for microdiameter. The measurement principle and mathematical model are described. A novel grayscale barycenter extraction algorithm... Based on structured-light vision measurement technology, we study a measuring method for microdiameter. The measurement principle and mathematical model are described. A novel grayscale barycenter extraction algorithm along the radial direction is proposed, which can precisely gather the image coor- dinates of the ellipse-shaped light-stripe centers. The accuracy of the measurement result shows marked improvement by using the algorithm. The method executes circle fitting to the measured three-dimensional (3D) data using linear least square method, which can acquire the diameter, surface profile, and other information of the object effectively. On the scene, a line-structured light vision system using the presented method is applied to measure the curvature radius of metal blades. Experimental results show that the measurement precision of the system is higher than 2 μm. 展开更多
关键词 Measuring method for micro-diameter based on structured-light vision technology AUTOCAD
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A lattice measuring method based on integral imaging technology 被引量:1
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作者 ZHANG Xiao-dong LI Suo-yin +3 位作者 HAN Zhi-guo ZHAO Lin LIANG Fa-guo WU Ai-hua 《Optoelectronics Letters》 EI 2021年第5期313-316,共4页
Aiming at the problem that the lattice feature exceeds the view field of the scanning electron microscope(SEM)measuring system,a new lattice measuring method is proposed based on integral imaging technology.When the s... Aiming at the problem that the lattice feature exceeds the view field of the scanning electron microscope(SEM)measuring system,a new lattice measuring method is proposed based on integral imaging technology.When the system works,the SEM measuring system is equivalent to an integral image acquisition system.Firstly,a lattice measuring method is researched based on integral imaging theory.Secondly,the system parameters are calibrated by the VLSI lattice standard.Finally,the value of the lattice standard to be tested is determined based on the calibration parameters and the lattice measuring algorithm.The experimental results show that,compared with the traditional electron microscope measurement method,the relative error of the measured value of the algorithm is maintained within 0.2%,with the same level of measurement accuracy,but it expands the field of view of the electron microscope measurement system,which is suitable for the measurement of samples under high magnification. 展开更多
关键词 SEM IMAGE A lattice measuring method based on integral imaging technology
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Method based on broadband compressed pulse superposition to measure properties of underwater acoustic materials 被引量:2
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作者 LI Shui,MIAO Rongxing (National Defence Underwater Acoustic Metrology Center Fuyang Zhejiang 311400) 《Chinese Journal of Acoustics》 2001年第1期52-60,共9页
A method is proposed for the measurements of the performances of underwater acoustic finite sized large area material samples in a free field by using broadband pulse compression technique. As the result of which, th... A method is proposed for the measurements of the performances of underwater acoustic finite sized large area material samples in a free field by using broadband pulse compression technique. As the result of which, the low-frequency cutoff of the standard tests is obviously reduced, and the broadband measurements are also realized. The experimental system provides measurements of complex reflection and transmission coefficients at continuous frequency points. From the data one can obtain the following acoustic parameters: echo reduction and insertion loss, absorption and attenuation coefficients, etc. The measurements are performed for two actual panels with the size 1 m x 1 m in the frequency range from 2-20 kHz. 展开更多
关键词 method based on broadband compressed pulse superposition to measure properties of underwater acoustic materials
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