中国科学院机构知识库网格系统: 检索

The Bo-Tai Line: Establishing the concepts of a balanced regional development line and a national development backbone 期刊论文 OAI收割
JOURNAL OF GEOGRAPHICAL SCIENCES, 2021, 卷号: 31, 期号: 6, 页码: 839-858
作者: Fang Chuanglin

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Bo-Tai Line identification line for regional balanced development Hu Huanyong Line important function construction conception

The Bo-Tai Line: Establishing the concepts of a balanced regional development line and a national development backbone 期刊论文 OAI收割
JOURNAL OF GEOGRAPHICAL SCIENCES, 2021, 卷号: 31, 期号: 6, 页码: 839-858
作者: Fang Chuanglin

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收藏 | 浏览/下载：16/0 | 提交时间：2021/08/19

Bo-Tai Line identification line for regional balanced development Hu Huanyong Line important function construction conception

Evaluation of the Radiation Benefits of Soil Conservation Services in the Longdong Loess Plateau Important Eco-Function Area in China 期刊论文 OAI收割
Geology; Meteorology & Atmospheric Sciences; Water Resources, 2012, 卷号: 5, 期号: 1, 页码: 146-151
Han, Yongwei; Li, Feng; Gao, Jixi; Wang, Baoliang; Liu, Chengcheng; Gao, Xinting

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soil conservation ecosystem services radiation benefit important eco-function area Longdong loess plateau of China

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.

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.

Research on infrared dim-point target detection and tracking under sea-sky-line complex background (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Infrared Imaging and Applications, May 24, 2011 - May 24, 2011, Beijing, China
作者: Dong Y.-X.; Zhang H.-B.; Li Y.; Li Y.; Li Y.

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Target detection and tracking technology in infrared image is an important part of modern military defense system. Infrared dim-point targets detection and recognition under complex background is a difficulty and important strategic value and challenging research topic. The main objects that carrier-borne infrared vigilance system detected are sea-skimming aircrafts and missiles. Due to the characteristics of wide field of view of vigilance system the target is usually under the sea clutter. Detection and recognition of the target will be taken great difficulties.There are some traditional point target detection algorithms such as adaptive background prediction detecting method. When background has dispersion-decreasing structure the traditional target detection algorithms would be more useful. But when the background has large gray gradient such as sea-sky-line sea waves etc.The bigger false-alarm rate will be taken in these local area.It could not obtain satisfactory results. Because dim-point target itself does not have obvious geometry or texture feature in our opinion from the perspective of mathematics the detection of dim-point targets in image is about singular function analysis.And from the perspective image processing analysis the judgment of isolated singularity in the image is key problem. The foregoing points for dim-point targets detection its essence is a separation of target and background of different singularity characteristics.The image from infrared sensor usually accompanied by different kinds of noise. These external noises could be caused by the complicated background or from the sensor itself. The noise might affect target detection and tracking. Therefore the purpose of the image preprocessing is to reduce the effects from noise also to raise the SNR of image and to increase the contrast of target and background. According to the low sea-skimming infrared flying small target characteristics the median filter is used to eliminate noise improve signal-to-noise ratio then the multi-point multi-storey vertical Sobel algorithm will be used to detect the sea-sky-line so that we can segment sea and sky in the image. Finally using centroid tracking method to capture and trace target. This method has been successfully used to trace target under the sea-sky complex background. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

On optimal guidance arithmetic of Super-maneuverable aircraft (EI CONFERENCE) 会议论文 OAI收割
30th Chinese Control Conference, CCC 2011, July 22, 2011 - July 24, 2011, Yantai, China
作者: Liu Y.; Gong Y.; Wang Z.; Wang Z.; Liu Y.

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Due to the complexity of maneuverability Super-maneuver attack guidance of modern aircraft has become the most important function to be immediately solved and perfectly completed. Proceed from the maneuvering optimization position and based on the optimal control theory the optimal angle maneuver guidance arithmatic is proposed. On the basis of aircraft maneuver guidance algorithm we come up with a variety of constraint condition optimized index and optimization rule and present a set of steepest optimal angle maneuver guidance algorithm and the validity and feasibility of the steepest optimal angle maneuver guidance algorithm has been comfirmed by the super-maneuver guidance simulation. 2011 Chinese Assoc of Automati.

Thermal-structure analysis of supersonic dome based on three materials (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Electric Information and Control Engineering, ICEICE 2011, April 15, 2011 - April 17, 2011, Wuhan, China
Jiang Z.; Ai X.; Wei Q.; Liu B.; Jia H.

收藏 | 浏览/下载：25/0 | 提交时间：2013/03/25

To a supersonic missile a seeker could enhance the aerodynamic ability due to decrease the resistance in flying. At the same time the primary function of a seeker has been considered as the most important equipment for a missile due to the importance for cueing of targets and tracking for the final approach. However the dome of a seeker which is made up of glass has poor mechanical performance. Especially in the higher altitude for a dome in which the aerothermal and pressure loads could destroy the structure easily it is necessary to do the thermal-structure coupled analysis due to varied materials. In the paper to take the spherical dome of a seeker as a example the analysis has been completed according to the varied materials consist of MgF2 Al2O3 and ZnS. The temperature loads and the pressure loads derived from the results of fluent analysis has been forced on the surface of dome which simulates the actual Mach 2.5 in flying. According to the results of coupled analysis the SEQV stress of the dome radium 80mm based on three materials had reached to 31MPa which shows that the strength is sufficient for Mach 2.5 and offered the warranty to design the attaching to missile for the dome. At the same time the results required the flexible mounting for the dome due to the displacements results which the crystal material couldn't accept. 2011 IEEE.

Modular aircraft simulation platform based on simulink (EI CONFERENCE) 会议论文 OAI收割
2010 IEEE International Conference on Mechatronics and Automation, ICMA 2010, August 4, 2010 - August 7, 2010, Xi'an, China
Chen C.-Q.; Ji Y.

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Aircraft simulation platform is the most important supporting technology in the aircraft development process. This simulation platform can be used for validating the design of subsystem and also it provides the necessary data for the Aircraft design. Wind has great impact on the flight parameter. In order to accurately simulate the wind model and calculate the flight parameters a simulation modeling method for flight parameter simulation platform under wind field environment is established. Firstly the various sub-systems which affecting flight parameters are analyzed some mathematical models of the flight parameter simulation platform is established. Secondly the atmospheric wind field is studied to analyze the impact on its trajectory. Then the model is built in the Simulink toolbox in the Matlab which is based on the principles of hierarchy and modularity using C MEX S-function for the complex kinetic equations. Finally when the models have been established encapsulating models for several subsystem and assembling them for the Aircraft simulation platform based on the unified interface. The simulation tests (including the performance test of a certain gliding Aircraft the wind influence test of a certain uncontrolled aircraft) prove the simulation capability of the platform and its calculating step can reach 1 ms. Comparing simulation with field test data of a certain uncontrolled aircraft it shows that the relative deviation of range is 0.47% the relative deviation of maximal altitude is 2.1%. Taking relevant standards as a reference standard it is demonstrated the platform is reliable meets the engineering accuracy requirements. 2010 IEEE.

Auto-focusing evaluation functions in digital image system (EI CONFERENCE) 会议论文 OAI收割
2010 3rd International Conference on Advanced Computer Theory and Engineering, ICACTE 2010, August 20, 2010 - August 22, 2010, Chengdu, China
作者: Gao Y.

收藏 | 浏览/下载：20/0 | 提交时间：2013/03/25

Evaluation function is an important item to measure the quality of images in auto-focusing systems. This paper introduces four categories of evaluation functions which are respectively based on gradient correlation statistics and transform. These functions formally differ from each other and their performances are not consistent when dealing with different images. The same function also performs different when the processed images have different characteristics. Five commonly used functions from the four categories are verified and compared under different circumstances in order to validate their performances. The result provides references for variety of selections in the practical application. 2010 IEEE.