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Visual Passive Ranging Method Based on Re-entrant Coaxial Optical Path and Experimental Verification
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作者 杨金宝 刘建国 +1 位作者 祝宁华 于丽娟 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第12期32-36,共5页
To overcome the shortcomings of the traditional passive ranging technology based on image, such as poor ranging accuracy, low reliability and complex system, a new visual passive ranging method based on re-entrant coa... To overcome the shortcomings of the traditional passive ranging technology based on image, such as poor ranging accuracy, low reliability and complex system, a new visual passive ranging method based on re-entrant coaxial optical path is presented. The target image is obtained using double cameras with coaxial optical path. Since there is imaging optical path difference between the cameras, the images are different. In comparison of the image differences, the target range could be reversed. The principle of the ranging method and the ranging model are described. The relationship among parameters in the ranging process is analyzed quantitatively. Meanwhile,the system composition and technical realization scheme are also presented. Also, the principle of the method is verified by the equivalent experiment. The experimental results show that the design scheme is correct and feasible with good robustness. Generally, the ranging error is less than 10% with good convergence. The optical path is designed in a re-entrant mode to reduce the volume and weight of the system. Through the coaxial design,the visual passive range of the targets with any posture can be obtained in real time. The system can be widely used in electro-optical countermeasure and concealed photoelectric detection. 展开更多
关键词 Visual Passive ranging method Based on Re-entrant Coaxial Optical Path and Experimental Verification
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A new method of passive ranging for underwater target:distance information extraction based on wave guide invariant 被引量:9
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作者 LI Qihu 《Chinese Journal of Acoustics》 CSCD 2015年第2期97-106,共10页
The study of wave guide invariant in underwater acoustics is one of attracted topics in recent 30 years. The interferences of direct wave and reflect wave from sea surface and sea bottom of underwater target radiated ... The study of wave guide invariant in underwater acoustics is one of attracted topics in recent 30 years. The interferences of direct wave and reflect wave from sea surface and sea bottom of underwater target radiated noise inherent the information of target distance. Extraction of these distance information will provide a possible new way in passive ranging for underwater target. The theoretical analysis and the results of at sea experiments show that the LOFAR (Low Frequency Analysis Record) figure inherently contains the range and moving information of passive acoustic sources, even in the situation that the receiver is only one single hydrophone. The theoretical analysis of extraction of target distance information by using wave guide invariant is presented in this paper. It is shown that, based on the interference striation pattern of target, the hydrophone array system is possible to extract the distance information with quite high array gain. Although the mathematical constrain conditions in forming interference striation pattern are different for individual array element, but it is proved that the differences of time delays between array elements can be used in compensation of beamforming. The theoretical analysis, system simulation and some results of at sea experiment show a new way in passive ranging and target recognition. 展开更多
关键词 WAVE A new method of passive ranging for underwater target
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Length estimation of extended targets based on bistatic high resolution range profile 被引量:1
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作者 屈泉酉 郭琨毅 盛新庆 《Journal of Beijing Institute of Technology》 EI CAS 2015年第3期387-391,共5页
The approach to estimate the length of extended targets by using the bistatic high resolution range profile( H RRP) is analyzed in this paper. The relationship between the bistatic H RRP and the monostatic H RRP of ... The approach to estimate the length of extended targets by using the bistatic high resolution range profile( H RRP) is analyzed in this paper. The relationship between the bistatic H RRP and the monostatic H RRP of extended targets are investigated. It is demonstrated by simulations that the target length measured by the bistatic H RRP is more meaningful and accurate than that by the monostatic HRRP,though the monostatic H RRP has been well developed and widely used in target recognizing and classification. The estimation results of a cone shaped target are present and compared at the end of the paper. To assure the reliability of the simulation,the bistatic H RRP is obtained through the scattering field data calculated by a fullwave numerical method,FE-BI-MLFMA. 展开更多
关键词 bistatic radar high resolution range profile(HRRP) full-wave numerical method length estimation
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Forecasting Diabetes Patients Attendance at Al-Baha Hospitals Using Autoregressive Fractional Integrated Moving Average (ARFIMA) Models
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作者 Salem Al Zahrani Fath Al Rahman Al Sameeh +1 位作者 Abdulaziz C. M. Musa Ashaikh A. A. Shokeralla 《Journal of Data Analysis and Information Processing》 2020年第3期183-194,共12页
Diabetes has become a concern in the developed and developing countries with its growing number of patients reported to the ministry of health records. This paper discusses the use of the Autoregressive Fractional Mov... Diabetes has become a concern in the developed and developing countries with its growing number of patients reported to the ministry of health records. This paper discusses the use of the Autoregressive Fractional Moving Average (ARFIMA) technique to modeling the diabetes patient’s attendance at Al-Baha hospitals using monthly time series data. The data used in the analysis of this paper are monthly readings of diabetes patients data covered the period January 2006-December 2016. The data were collected from the General Directorate of Health Affairs, Al-Baha region. The autoregressive fractional moving average approach was applied to the data through the model identification, estimation, diagnostic checking and forecasting. Hurst test results and ACF confirmed that there is a long memory behavior in diabetic patient’s data. Also, the fractional difference to diabetes series data revealed that (<em>d</em> = 0.44). Moreover, unit root tests indicated that the fractional difference of diabetes series level is stationary. Furthermore, according to AIC and BIC of model selection criteria ARFIMA (1, 0.44, 0) model shown the smallest values, hence this model was chosen as an adequate represents the data. Also, a diagnostic check confirmed that ARFIMA was appropriate and highly recommended in modeling and forecasting this type of data. 展开更多
关键词 Long Memory ARFIMA Rescaled Range R/S method Diabetes Patients
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Effect of diffraction on the ultrasonic velocity measuredby the pulse interference method in VHF range 被引量:1
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作者 WEI Tingcun(Department of Electrical Engineering, Tohoku University Japan) 《Chinese Journal of Acoustics》 2002年第1期30-35,共6页
The effect of diffraction on the ultrasonic velocity measured by the pulse interference method has been investigated in VHF range theoretically and experimentally. Two silicate glasses are taken as the specimens, thei... The effect of diffraction on the ultrasonic velocity measured by the pulse interference method has been investigated in VHF range theoretically and experimentally. Two silicate glasses are taken as the specimens, their frequency dependences of longitudinal velocities are measured in the frequency range of 50-350 MHz, and the phase advances of ultrasonic signals caused by diffraction effect are calculated using A. O. Williams' theoretical expression. For the velocity error due to diffraction effect, the experimental results are in good agreement with the theoretical prediction. It has been shown that the velocity error due to diffraction effect is directly proportional to dθ21 (f)/df, whereθ21 (f) is the phase advances difference between the two partial reflection signals used in velocity measurement and f is the ultrasonic frequency. 展开更多
关键词 Effect of diffraction on the ultrasonic velocity measuredby the pulse interference method in VHF range VHF
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A novel method to determine the FOCAL energy range
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作者 张冬青 王向朝 施伟杰 《Chinese Optics Letters》 SCIE EI CAS CSCD 2005年第10期589-592,共4页
Determination of the energy range is an important precondition of focus calibration using alignment procedure (FOCAL) test. A new method to determine the energy range of FOCAL off-lined is presented in this paper. I... Determination of the energy range is an important precondition of focus calibration using alignment procedure (FOCAL) test. A new method to determine the energy range of FOCAL off-lined is presented in this paper. Independent of the lithographic tool, the method is time-saving and effective. The influences of some process factors, e.g. resist thickness, post exposure bake (PEB) temperature, PEB time and development time, on the energy range of FOCAL are analyzed. 展开更多
关键词 LINE AO A novel method to determine the FOCAL energy range
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Numerical study for bio-convection effects on MHD nano-fluid flow past a porous and extending wedge
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作者 Bagh Ali Muhammad Ilyas +3 位作者 Imran Siddique Huizhu Yang Muhammad Kamran Ashraf Sohaib Abdal 《Propulsion and Power Research》 SCIE 2023年第4期584-594,共11页
We explored the insinuations of bio-convection and thermal radiation on nanofluid transportation across stretching permeable wedge with magnetic force.Appropriate similarity transformation variables are utilized to ac... We explored the insinuations of bio-convection and thermal radiation on nanofluid transportation across stretching permeable wedge with magnetic force.Appropriate similarity transformation variables are utilized to achieve ordinary differential equations.In order to tackle the non-linearity of these equations,numerical procedure based on shooting technique and Range Kutta method are harnessed on MATLAB platform.Computational and devour is carried out to evaluate the influence of controlling limitations on temperature,velocity,concentration of nanofluids and micro-organisms density.The growing strength of thermophoresis and Brownian motion enhance the fluid temperature.The profile volume fraction show decline against higher values of parameters which are Lewis number,unsteadiness and Brownian motion but opposite trend noted against higher value of Williamson and thermophoresis parameters.The skin friction values rise with the growing values of parameter of wedge angle for the moving wedge.The motile organism profile exhibits decrease against growing strength of Peclet number,bioconvection Lewis number,temperature difference and unsteady parameters while opposite behavior has been noted against wedge angle parameter. 展开更多
关键词 MHD NANOFLUID BIOCONVECTION Porous stretching wedge Range Kutta method
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Measurement on the Construction Level of China's Green, Low-Carbon, and Circular-Development Economic System
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作者 ZHANG Youguo DOU Ruoyu BAI Yujie 《China Economic Transition》 2023年第1期1-33,共33页
This study aims to measure how well China's green,low-carbon,and circulardevelopment economic system(theGLCCD Economic System)is being developed.By establishing the indicator system and indicators,the spatiotempor... This study aims to measure how well China's green,low-carbon,and circulardevelopment economic system(theGLCCD Economic System)is being developed.By establishing the indicator system and indicators,the spatiotemporal range entropy weight method,Gini coefficient,Theil index,convergence model,and national and provincial data from 2012 to 2017 are employed.The construction level of almost all GLCCD Economic Systems at national and provincial levels has shown improvement during the study period.Among them,a significant boost is only observed in the development power indicator;improvement in the production system indicator and development benefit indicatorismild,andthelifesystemindicator sees a decline year by year.The construction level of the GLCCD Economic System throughout China is generally balanced but tends to expand in scale.However,the inter-regional developmenttbenefit indicator showsaconvergence trend.Based on the analysis of the similarities and differences between greenandlow-carboncircular development,the development power and development benefit,production system,and life system are incorporated into a unified logical framework.The construction level of the GLCCD Economic System is measured as a whole in a holistic manner.This study finds out the scientific connotation oftheGLCCD Economic System.The changing trends and regional differences in the construction level of the GLCCD Economic System are revealed.These findings provide a clear and reliable decision-making basis for the construction of the GLCCD Economic System. 展开更多
关键词 green low-carbon and circular development indicator system spatiotemporal range entropy weight method Gini coefficient Theil index
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Ultra-wide tuning single channel filter based on one-dimensional photonic crystal with an air cavity 被引量:1
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作者 Xiaodan Zhao Yibiao Yang +3 位作者 Zhihui Chen Yuncai Wang Hongming Fei Xiao Deng 《Journal of Semiconductors》 EI CAS CSCD 2017年第2期26-30,共5页
By inserting an air cavity into a one-dimensional photonic crystal of LiF/GaSb, a tunable filter covering the whole visible range is proposed. Following consideration of the dispersion of the materials, through modula... By inserting an air cavity into a one-dimensional photonic crystal of LiF/GaSb, a tunable filter covering the whole visible range is proposed. Following consideration of the dispersion of the materials, through modulating the thickness of the air cavity, we demonstrate that a single resonant peak can shift from 416.1 to 667.3 nm in the band gap at normal incidence by means of the transfer matrix method. The research also shows that the transmittance of the channel can be maximized when the number of periodic Li F/Ga Sb layers on one side of the air defect layer is equal to that of the other side. When adding a period to both sides respectively, the full width at half maximum of the defect mode is reduced by one order of magnitude. This structure will provide a promising approach to fabricate practical tunable filters in the visible region with ultra-wide tuning range. 展开更多
关键词 photonic crystal filters transfer matrix method single resonant peak ultra-wide tuning range mechanical modulation
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