中国科学院机构知识库网格系统: 检索

Approaches to assessing the daily average ground surface soil heat flux on a regional scale over the Qinghai-Tibet Plateau 期刊论文 OAI收割
AGRICULTURAL AND FOREST METEOROLOGY, 2023, 卷号: 336, 页码: 13
作者: Yang, Cheng; Wu, Tonghua; Hu, Guojie; Zhu, Xiaofan; Yao, Jimin

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收藏 | 浏览/下载：67/0 | 提交时间：2023/10/09

Qinghai-Tibet Plateau Daily average ground surface soil heat flux Remote sensing-based model Combination method Sine method

Tracking error estimate for theodolite based on general regression neural network (EI CONFERENCE) 会议论文 OAI收割
3rd international Conference on Manufacturing Science and Engineering, ICMSE 2012, March 27, 2012 - March 29, 2012, Xiamen, China
作者: Li M.

收藏 | 浏览/下载：17/0 | 提交时间：2013/03/25

To efficiently evaluate the tracking index of theodolite as well as avoiding influence resulted from higher harmonics when used opto dynamic target and use equivalent sine to evaluate the tracking index in this paper we resorted to General Regression Neural Network to do the new research on theodolite tracking accuracy evaluation method. Experimental results indicate that the method realized the equivalent sine to evaluate the tracking index of theodolite and avoided the higher harmonics influence with opto dynamic target. The research in this paper has important value to the engineering practice. (2012) Trans Tech Publications.

The Research of real time auto-recognition of the moire fringe (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Imaging Detectors and Applications, May 24, 2011 - May 26, 2011, Beijing, China
Wang M.-J.; Wu Z.-G.

收藏 | 浏览/下载：18/0 | 提交时间：2013/03/25

Measuring the movement of raster by the method of moire fringe has the advantage of high sensitivity high resolution and non-contacted measurement. The characteristic of moire fringe is that the image is white alternate with black the angle of the stripes is uniform the width of the stripes is uniform the terminators of the stripes aren't clear. A fast method that can figure out the width and angle of the moire fringe precisely is put forward in this paper. It calculates the angle the stripes firstly. According to the principle of the minimum mean squared error (MMSE) the closer a series of data is the smaller the value of the MMSE will be. The method is described as follows: It takes the image's center as the origin 180 beelines pass through the origin with the same angle interval. it calculates the value of the minimum mean squared error of the 180 beelines and find out the least one among those then the angle of the moire fringe comes out primarily. In order to improving the calculating precision of moire fringe 60 equal angles are divided in the neighborhood of the angle then a precise angle of moire fringe is calculated according to the principle of the MMSE. After getting out the angle of the moire fringe we begin to calculate the width of moire fringe. A line vertical with the moire fringe is drawn and we can get the width of the moire fringe by the vertical line. In order to get over the influence of the noise an effective area with the shape of diamond is selected in the image. The data of area is accumulated and projected according to the direction of moire fringe and a sine curve come out. The width of moire fringe can be obtained by getting the position of the first wave crest the position of the last wave crest and the number of wave crest. Experiments prove that the precision of the method put forward in this paper is enhanced in comparison with the traditional frequency method the precision of width calculation achieves to 99.6% according to the evaluation indicators of width detection error. The computing speed is boosted largely compared with traditional method and it can achieve with 15 ms that satisfying the demand of real time. 2011 SPIE.

New phase measurement method for laser rangefinder (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, April 26, 2010 - April 29, 2010, Dalian, China
作者: Meng Z.; Meng Z.

收藏 | 浏览/下载：25/0 | 提交时间：2013/03/25

A new phase measurement method is designed and presented by using the technique of signal shifting phase and the technique of signal multiplication for laser rangefinder. The intensity of laser light is modulated by cosine circuit signal at the same time the cosine circuit signal is thansformed sine signal by the shifting phase technique. Two signals mentioned above are multiplied by received signal from the target respectively then being transmitted into signal processor after passing through low band filter respectively. The result of phase-shift between the received signal and sent signal is calculated by means of signal processor and time-counter with double frequency of modulation signal. The proposed system is composed of four units such as control and count unit emitting and receiving unit of laser light signal processing unit and result display unit. The two most advantages of proposed system over others are its ability of proper isolation which reduces crosstalk and its independency thermal drift. Theoretical calculations and experimental results have shown the accuracy better than 2 mm. 2010 Copyright SPIE - The International Society for Optical Engineering.

Method for recovering dynamic position of photoelectric encoder (EI CONFERENCE) 会议论文 OAI收割
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, November 19, 2008 - November 21, 2008, Chengdu, China
作者: Sun Y.; Liu Y.-S.; Liang L.-H.; Sun Y.; Wan Q.-H.

收藏 | 浏览/下载：16/0 | 提交时间：2013/03/25

This paper presents a method to recover dynamic position of photoelectric encoder. While working at dynamic state original outputs of the photoelectric encoder are in theory two sine or triangular signals with a phase difference of /2. However there are still deviations of actual output signals. Interpolating on the basis of this deviation signal will result in interpolation errors. In dynamic state true original signal data obtained by data acquisition system is a time equation. Through processing these data by data equiangular and harmonic analysis the equation will be converted from time domain to position domain and an original position equation can be formed. Then the interpolation errors also can be obtained. By this method the interpolation errors can be checked in dynamic state and it can also provide electric interpolation basis so that to improve dynamic interpolation precision of the encoder. Software simulation and experimental analysis all prove the method effective. This method is he basis in theory for precision checking and calibration in motion. 2009 SPIE.

System identification of tracking error and evaluation of tracking performance using BP neural network (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2009: Advances in Infrared Imaging and Applications, June 17, 2009 - June 19, 2009, Beijing, China
Zhang N.; Shen X.-H.

收藏 | 浏览/下载：19/0 | 提交时间：2013/03/25

A novel approach for evaluating the tracking performance of optoelectronic theodolite is proposed. First an equivalent mathematic model of tracking error is established. Then the equivalent sine signal is inputted to the equivalent model and the outputs are sampled. The results of evaluating the tracking performance are obtained based on the statistical calculation of output produced by equivalent model. Equivalent model using the BP (Backprogration) neural network structure is identified. The training method of BP neural network adopts the LM (Levenberg-Marquardt) algorithm for the sake of speeding up training process. The BP neural network is trained and tested by using the training and testing samples gotten from the simulation model of optoelectronic theodolite tracking system under MATLAB/SIMULINK. The estimate errors of equivalent model including average error maximum error and standard error are 2.5872e-0060 2.8 and 1.9. The results show that the equivalent model identified based on BP neural network meets the needs of evaluating the tracking performance of optoelectronic theodolite. The accurate evaluation of tracking performance is achieved. 2009 SPIE.

Eigenfrequency computation by the finite sine transform method on a rectangular plate carrying arbitrary number of concentrated masses and springs 会议论文 OAI收割
14th International Congress on Sound and Vibration 2007, ICSV 2007, Cairns, QLD, Australia, July 9, 2007 - July 12, 2007
作者: Zhang Y(张吟)

收藏 | 浏览/下载：20/0 | 提交时间：2017/06/01

Arbitrary number Combined method Concentrated mass Eigen frequencies Eigenfrequency Mode shapes Rectangular plates Sine transforms

An application of the modified Adomian decomposition method for (N+1)-dimensional sine-Gordon field 期刊论文 OAI收割
APPLIED MATHEMATICS AND COMPUTATION, 2006, 卷号: 181, 期号: 1, 页码: 147-152
作者: Wang, Qi

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收藏 | 浏览/下载：26/0 | 提交时间：2018/07/30

(N+1)-dimensional sine-Gordon field modified Adomian decomposition method Jacobi elliptic function solution error analysis

Discrete exact solutions of modified Volterra and Volterra lattice equations via the new discrete sine-Gordon expansion algorithm 期刊论文 OAI收割
NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS, 2006, 卷号: 64, 期号: 8, 页码: 1798-1811
作者: Yan, ZY

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收藏 | 浏览/下载：11/0 | 提交时间：2018/07/30

discrete soliton equations discrete sine-Gordon expansion method solitary wave solution symbolic computation

Numerical solution for series sine-Gordon equations using variational method and finite element approximation 期刊论文 OAI收割
APPLIED MATHEMATICS AND COMPUTATION, 2005, 卷号: 168, 期号: 1, 页码: 567-599
作者: Wang, QF

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收藏 | 浏览/下载：24/0 | 提交时间：2018/07/30

sine-Gordon equations numerical solution finite element methods Gauss-Legendre quadrature Runge-Kutta method