中国科学院机构知识库网格系统: 检索

Direct Approach to Treatment of Contact in Numerical Manifold Method 期刊论文 OAI收割
INTERNATIONAL JOURNAL OF GEOMECHANICS, 2017, 卷号: 17, 期号: 5, 页码: -
作者: Yang, Yongtao; Zheng, Hong

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收藏 | 浏览/下载：19/0 | 提交时间：2018/06/05

Numerical manifold methods (NMM) Mathematical cover Physical cover Contact Penalty parameter Direct approach Lagrange multiplier method

Mathematical modeling of autotrophic denitrification (AD) process with sulphide as electron donor 期刊论文 OAI收割
WATER RESEARCH, 2016, 卷号: 91, 页码: 225-234
作者: Xu, Guihua; Yin, Fengjun; Chen, Shaohua; Xu, Yuanjian; Yu, Han-Qing

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收藏 | 浏览/下载：21/0 | 提交时间：2018/03/15

Autotrophic denitrification (AD) Mathematical modeling Sulphide Kinetic approach

Linear auto disturbance rejection controller for vector-controlled PMSM drive system (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Transportation, Mechanical, and Electrical Engineering, TMEE 2011, December 16, 2011 - December 18, 2011, Changchun, China
作者: Zhang K.; Zhang K.; Zhang K.; Zhang K.

收藏 | 浏览/下载：36/0 | 提交时间：2013/03/25

A high-performance robust controller of permanent-magnet synchronous motor (PMSM) drive with cascade linear auto disturbance rejection controller (LADRC) is proposed. The robust controller combines the simplicity of linear controller and the merit of the auto disturbance rejection controller (ADRC). First a systematic mathematical model is derived according to the required specifications for the PMSM drive system. Then for the model this paper designs the controller that includes three first-order LADRCs. The controller does not rely on the accurate mathematical model of motor. The controller can estimate and compensate the disturbances that include load disturbance and systematic parameters changes by the linear extended state observer (LESO). Simulation results show that compared with conventional PI controller the proposed approach has strong robustness. In the same load disturbance the speed fluctuation of the LADRCs accounts for 30% of PI controller. 2011 IEEE.

Gimbal displacement error analysis on an electro-optical seeker (EI CONFERENCE) 会议论文 OAI收割
Optical Design and Testing IV, October 18, 2010 - October 20, 2010, Beijing, China
作者: Zhang X.; Zhang X.; Zhang X.

收藏 | 浏览/下载：35/0 | 提交时间：2013/03/25

It is essential to analyze the gimbal displacement errors for a seeker due to the importance for cueing of targets and tracking for the final approach. Otherwise for a seeker electro-driven with a concentric glass dome the large errors will decrease the picking pointing and tracking precision rooted from the displacement errors existing between the rotation center of the optical system and the gimbal. And the gimbaled camera system displacement errors are never eliminated but reduced due to the geometric errors consists of geometric tolerances of gimbal structure manufacture installation and vibration coming from working environment. In this paper the gimbal displacement errors in an electro-optically stabilized platform resulting from geometric errors and environment errors were analyzed and shown in detail. The mathematical modal of the gimbal displacement errors created based on multi-body dynamics demonstrated the connection between the gimbal displacement errors and the stabilized platform. Taking a visible light image seeker as a case the diameter is 120mm and the geometric tolerances came from the values of primary design and the vibration data came from the environmental vibration test on the pitch-yaw seeker and at the same time the errors resulting from installation were considered too. Based on calculating the maximum gimbal displacement error will reach to 0.2mm for pitching angle smaller than 40 and yawing angle smaller than 60. However the critical parts have been found out according to the probability theory and the reliability analysis successfully used in the paper and finally the maximum gimbal displacement error reduced to 0.1mm which is acceptable corresponding to the picking pointing and tracking precision for an optical imaging seeker. 2010 Copyright SPIE - The International Society for Optical Engineering.

The method on the measurement of the aircraft attitude by the spatial cosines relationship of the single station and planes to the intersection the multi-station of electro-optical theodolite (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on Computer, Mechatronics, Control and Electronic Engineering, CMCE 2010, August 24, 2010 - August 26, 2010, Changchun, China
Zhao L.-R.; Cao Y.-G.

收藏 | 浏览/下载：17/0 | 提交时间：2013/03/25

In order to realize the aircraft attitude measurement The paper advances electro-optical theodolite methods of measuring the aircraft attitude by using the spatial cosines relationship the single station theodolite and how to use intersection of the multi-station theodolite. The single station theodolite was introduced in a measured distance from the aircraft posture information. An exhaustive approach was used to access to the aircraft axis of the feature points and the location in the space was used to obtain space posture parameters. The multi-station theodolite was introduced to get the information of the aircraft flight attitude by method of using planes to the intersection. Two-dimensional image to obtain objective axis by fitting algorithm using Hough transform. And then Calculate the vertical distance of the origin to the target of the central axis and the origin to the target of the central axis of the angle between the normal and the X-axis obtaining the linear equation in the two-dimensional plane. Two-dimensional axis of the target image and the camera system's optical center only identified a space plane. The aircraft yaw axis angle and pitch angle can be obtained by getting the space axis using plains to the intersection method. Experimental results show that attitude angle error of the single station theodolite is less than 1 when its distance is less than 6000m and attitude angle error of the multi-station theodolite is less than 0.6 when its intersection angle is between 30 and 150. In this paper according to test result of precision comparing the mathematical model is correct and the algorithm is reasonable in extracting effective parameters of the aircraft's attitude. 2010 IEEE.

Measuring the system gain of the TDI CCD remote sensing camera (EI CONFERENCE) 会议论文 OAI收割
Advanced Materials and Devices for Sensing and Imaging II, November 8, 2004 - November 10, 2004, Beijing, China
Ya-xia L.; Hai-ming B.; Jie L.; Jin R.; Zhi-hang H.

收藏 | 浏览/下载：62/0 | 提交时间：2013/03/25

The gain of a TDI CCD camera is the conversion between the number of electrons recorded by the TDI CCD and the number of digital units (counts) contained in the CCD image"[1]. TDI CCD camera has been a main technical approach for meeting the requirements of high-resolution and lightweight of remote sensing equipment. It is useful to know this conversion for evaluating the performance of the TDI CCD camera. In general a lower gain is better. However the resulting slope is the gain of the TDI CCD. We did the experiments using the Integration Sphere in order to get a flat field effects. We calculated the gain of the four IT-EI-2048 TDI CCD. The results and figures of the four TDI CCD are given. this is only true as long as the total well depth (number of electrons that a pixel can hold) of the pixels can be represented. High gains result in higher digitization noise. System gains are designed to be a compromise between the extremes of high digitization noise and loss of well depth. In this paper the mathematical theory is given behind the gain calculation on a TDI CCD camera and shows how the mathematics suggests ways to measure the gain accurately according to the Axiom Tech. The gains were computed using the mean-variance method also known as the method of photon transfer curves. This method uses the effect of quantization on the variance in the measured counts over a uniformly illuminated patch of the detector. This derivation uses the concepts of signal and noise. A linear fit is done of variance vs. mean

The geometric distortions correction of uncooled large-sized relative aperture infrared imaging system (EI CONFERENCE) 会议论文 OAI收割
Infrared Components and their Applications, November 8, 2004 - November 11, 2004, Beijing, China
作者: Sun Q.

收藏 | 浏览/下载：20/0 | 提交时间：2013/03/25

The geometric distortion of infrared image which was created by the large-sized relative aperture optical system. It could be corrected by the digital image processing technology. The magnitude of distortion would be enlarged quickly with the enlargement of relative aperture. Though the distortion could not impact on the articulation of the image it would affect geometric location precision of the image directly. In this paper the distortion correction of uncooled large-sized relative aperture infrared imaging system was discussed and the mathematical model of distortion correction was established. A algorithm of digital image processing was presented and applied based on control points by combining polynomial warping and space variant linear image interpolation. The method of polynomial warping was used to establish the locality relationship between the original image and the distortion ones. The space-variant linear image interpolation provided an efficient way to rebuild the frame of images. The computational costs of the proposed approach are very little and the precision is almost as high as the method of bicubic interpolation when compared to those of state-of-the-art nonlinear interpolation operators.

An entropic regularization approach for mathematical programs with equilibrium constraints 期刊论文 OAI收割
COMPUTERS & OPERATIONS RESEARCH, 2004, 卷号: 31, 期号: 13, 页码: 2249-2262
作者: Birbil, SI; Fang, SC; Han, JY

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收藏 | 浏览/下载：21/0 | 提交时间：2018/07/30

mathematical programs with equilibrium constraints smoothing approach entropic regularization online solvers

Mathematical approach to sedimentary component partitioning of polymodal sediments and its applications 期刊论文 OAI收割
PROGRESS IN NATURAL SCIENCE, 2001, 卷号: 11, 期号: 5, 页码: 374-382
作者: Sun, DH; An, ZS; Su, RX; Wu, XH; Wang, SM

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收藏 | 浏览/下载：27/0 | 提交时间：2020/05/28

grain-size components distribution function sediments mathematical approach

Mathematical approach to sedimentary component partitioning of polymodal sediments and its applications 期刊论文 OAI收割
PROGRESS IN NATURAL SCIENCE, 2001, 卷号: 11, 期号: 5, 页码: 374-382
Sun, DH; An, ZS; Su, RX; Wu, XH; Wang, SM; Sun, QL; Rea, DK; Vandenberghe, J

收藏 | 浏览/下载：30/0 | 提交时间：2011/07/03

grain-size components distribution function sediments mathematical approach