中国科学院机构知识库网格系统: 检索

Analysis of the gains and losses of ecosystem service value under land use change and zoning in Qiqihar 期刊论文 OAI收割
FRONTIERS IN ECOLOGY AND EVOLUTION, 2023, 卷号: 11, 页码: 14
作者: Zuo, Zhiqian; Yang, Yanzhao; Wang, Ran; Li, Jinxiao; Zhang, Pengtao

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收藏 | 浏览/下载：13/0 | 提交时间：2023/10/09

land use change ecosystem service value the flow-oriented model ecological function zoning Qiqihar city

Reentry guidance based on parametric optimization (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Mechatronics and Control Engineering, ICMCE 2012, November 29, 2012 - November 30, 2012, Guangzhou, China
作者: Li D.

收藏 | 浏览/下载：163/0 | 提交时间：2013/03/25

This paper presents a parametric optimization approach to solve reentry guidance. Due to the various constraints imposed on the trajectory original guidance problem can be converted into an optimal control problem with a merit function to be minimized. Direct implementation of method of variation and is too complex to get a reasonable result while a numerical parametric optimization approach is feasible and efficient if we choose appropriate control variables as the optimization parameters and effective optimization algorithm. A simulation of the approach is performed to show its validity on reentry guidance problem: as the value of merit function converges to acceptable threshold all constraints are hold. (2013) Trans Tech Publications Switzerland.

Null compensator testing convex freeform surface mirror with CGH technology (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Future Optical Materials and Circuit Design, FOMCD 2012, December 27, 2012 - December 28, 2012, Xiamen, China
作者: Zhang Z.-Y.; Zhang Z.-Y.; Zhang B.-Z.

收藏 | 浏览/下载：29/0 | 提交时间：2013/03/25

The Computer Generated Hologram (CGH) technique is the main method for optical testing the free form surface.For testing a convex free form surface mirror a CGH element with the surface testing interferometer and free form mirror precise position function was designed by use of appropriative software the testing precision was less than 0.011(=632.8nm) in RMS value by this means. (2013) Trans Tech Publications Switzerland.

A shape context based Hausdorff similarity measure in image matching 会议论文 OAI收割
5th International Symposium on Photoelectronic Detection and Imaging (ISPDI) - Infrared Imaging and Applications, Beijing, June 25-27, 2013
作者: Ma TL(马天磊); Liu YP(刘云鹏); Shi ZL(史泽林); Yin J(尹健)

收藏 | 浏览/下载：36/0 | 提交时间：2013/12/26

The traditional Hausdorff measure, which uses Euclidean distance metric (L2 norm) to define the distance between coordinates of any two points, has poor performance in the presence of the rotation and scale change although it is robust to the noise and occlusion. To address the problem, we define a novel similarity function including two parts in this paper. The first part is Hausdorff distance between shapes which is calculated by exploiting shape context that is rotation and scale invariant as the distance metric. The second part is the cost of matching between centroids. Unlike the traditional method, we use the centroid as reference point to obtain its shape context that embodies global information of the shape. Experiment results demonstrate that the function value between shapes is rotation and scale invariant and the matching accuracy of our algorithm is higher than that of previously proposed algorithm on the MEPG-7 database.

The design and implementation of temperature acquisition system based on PXI (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Control Engineering and Communication Technology, ICCECT 2012, December 7, 2012 - December 9, 2012, Shenyang, Liaoning, China
作者: Wang J.

收藏 | 浏览/下载：32/0 | 提交时间：2013/03/25

This paper introduces the design of temperature acquisition system which is based on the PXI-6251 DAQ device thermocouple acquisition module SCXI-1102 and the LabVIEW program language of NI. The design of temperature collection software and the configuration of hardware are described in details. The software developed in LabVIEW program language can acquire temperature data rapidly what's more the acquired data can be displayed real timely and saved to the disk. It is proved that the system is easy to practical use and can extraction mean square value and mean value after gathering the stable high-speed temperature. The function can be extended according to the demands of users. 2012 IEEE.

Tracking error modeling of the theodolite based on GRNN method (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Frontiers of Manufacturing and Design Science, ICFMD 2011, December 11, 2011 - December 13, 2011, Taichung, Taiwan
作者: Li M.

收藏 | 浏览/下载：24/0 | 提交时间：2013/03/25

To meet the requirement of high tracking accuracy as well as develop more reasonable evaluation method in this paper the General Regression Neural Network (GRNN) has been applied to build the tracking error model of the theodolite. First we analyze the nonlinear factors in the theodolite. Second we discuss the principle of GRNN including its structure the function as well as its priors. Third we build the tracking error model based on GRNN and verify the model through the different parameters. The result indicated that the network model based on GRNN has high accuracy and good generalization ability. It could instead the real system to a certain extent. The research in this paper has important value to the engineering practice.

Image quality assessment based on gradient complex matrix (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Systems and Informatics, ICSAI 2012, May 19, 2012 - May 20, 2012, Yantai, China
作者: Wang Y.; Wang Y.; Wang Y.; Wang Y.; Wang Y.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

An image quality assessment model based on gradient complex matrix is proposed. The vertical and horizontal gradient information of grayscale image is calculated. Complex number is used to construct the measuring matrix. Singular value decomposition is performed in order to obtain the main structure information of the image. The singular value feature vectors of the image gradient complex matrices corresponding to the reference image and the distorted image are used to measure the structural similarity of the two images. PSNR is taken as a tool to evaluate the gradient distribution similarity. Their properties are analyzed by using LIVE database and nonlinearity regression function. 2012 IEEE.

Structure buckling load interval analysis of supercavitating projectile (EI CONFERENCE) 会议论文 OAI收割
2011 9th International Conference on Reliability, Maintainability and Safety: Safety First, Reliability Primary, ICRMS'2011, June 12, 2011 - June 15, 2011, Guiyang, China
作者: Zhou L.

收藏 | 浏览/下载：26/0 | 提交时间：2013/03/25

As a result of supercavitating projectiles with high underwater velocity their structures undergo high longitudinal force. It is necessary to perform structure buckling load interval analysis because the uncertainty of structural own parameters should be considered. Critical buckling load of supercavitating projectiles is calculated by Galerkin method. The partial matrixes of critical buckling load implicit function to each uncertainty variable are deduced and the interval of structure critical buckling load is calculated by interval analysis and convex model methods. Numerical results show that the nominal value lower and upper bounds of critical buckling load increase with the increment of the ratio of base diameter to cavitator diameter. And the uncertainty degree of basic variables should be controlled as far as possible in the project for high reliability. 2011 IEEE.

Space camera dynamic image quality measurement and evaluation (EI CONFERENCE) 会议论文 OAI收割
3rd International Conference on Measuring Technology and Mechatronics Automation, ICMTMA 2011, January 6, 2011 - January 7, 2011, Shanghai, China
作者: Zhang X.; Zhang X.; Zhang X.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

By using analysis of the infinity image of the space camera we intend to obtain the curve of the dynamic modulation transfer function. We extract the pixel gray values at the image edge which distribute as a knife-edge function and make differential calculation and Fourier transformation of it and then we can obtain the dynamic MTF curve of the optical system. The value of the curve at the Nyquist frequency is the most important parameter that reflects the image quality. We add push-scanning imaging and environmental effects to the static MTF of space camera and compare the MTF value with the dynamic MTF at Nyquist frequency. The comparison result can help us verify the accuracy of the calculating results and the feasibility of our method. (2011) Trans Tech Publications.

Space optical remote sensor of the CAE thermal control index calculation method (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Advanced Design and Manufacturing Engineering, ADME 2011, September 16, 2011 - September 18, 2011, Guangzhou, China
作者: Li L.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

The thermal control indicators CAE methods of Space optical remote sensor are analyzed in the presented work. We sat up a thermal optical analysis model for space optical remote sensor. By assuming fully covered by in-orbit temperature load and using the finite element method for thermal deformation analysis we obtained the optical remote sensor surface deformation and displacement under various thermal loading. Using ZERNIKE polynomial wave was fitted to obtain ZERNIKE polynomial coefficients which were incorporated into the optical system design. Using CODE V optical calculation software heat-ray machines under elastic deformation of the system point spread function transfer function (MTF) wave front differential (WFE) etc. were calculated. Image quality changes of remote sensors are discussed in variety assumed cases such as temperature loads of quality change. By repeated iteration critical value of temperature fields meeting the design requirements are obtained for the optical system. Optical indicators were converged to the temperature field indicator then reasonable indicators of thermal control for remote sensors were obtained. For the thermal control design this method provided a reliable basis for design. (2011) Trans Tech Publications Switzerland.