中国科学院机构知识库网格系统: 检索

Determination of the maximal singularity-free zone in the whole workspace of 3-RRR planar parallel mechanism 会议论文 OAI收割
2015 IEEE International Conference on Cyber Technology in Automation, Control, and Intelligent Systems (CYBER), Shenyang, China, June 8-12, 2015
作者: Yang Q(杨强); Wang HG(王洪光); Li SJ(李树军)

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parallel mechanism singularity 3-RRR mechanism singularity-free zones kinematic analysis

A Practical Guide to Discrete Wavelet Decomposition of Hydrologic Time Series SCI/SSCI论文 OAI收割
2012
Sang Y. F.

收藏 | 浏览/下载：28/0 | 提交时间：2014/12/24

Hydrologic series analysis Discrete wavelet decomposition Reference energy function Significance testing Noise Uncertainty rainfall-runoff singularity detection spectral-analysis neural-networks climate-change model multiresolution identification variance scales

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).

United steering of control moment gyros for small satellite with limited gimbal rate (EI CONFERENCE) 会议论文 OAI收割
2010 IEEE International Conference on Information and Automation, ICIA 2010, June 20, 2010 - June 23, 2010, Harbin, Heilongjiang, China
Xu K.; Jin G.; Chen C.

收藏 | 浏览/下载：18/0 | 提交时间：2013/03/25

Single Gimbal Control Moment Gyroscopes (SGCMG) can could provide large control torque and quick attitude maneuver rate to small satellites without any increase in power volume and mass which will help small satellites become more powerful. Singularity avoidance and failure steering are two important problems to SGCMGs and also the main focus in this field. A new united steering law for SGCMGs with capabilities of singularity avoidance and quick transition of singularity surfaces is developed in this paper. To ensuring the existence of null motion the commanded output of controller was changed real-timely as the variation of singularity measurement of SGCMGs which can avoid the gimbal angle rate saturation. This developed steering law could help the SGCMGs provide real-time control toques in spite of limitation of gimbal angle rate. Simulation analysis is conducted for a certain 4-SGCMG system mounted on a small satellite. Simulation results indicate that the steering law is very effective in singularity avoidance. 2010 IEEE.

Singularity analysis for a 5-DoF fully-symmetrical parallel manipulator 5-(RRR) under bar(RR) 会议论文 OAI收割
IEEE International Conference on Robotics and Automation, Rome, ITALY, April 10-14, 2007
作者: Zhu SJ(朱思俊); Huang Z(黄真); Zhao MY(赵明扬)

收藏 | 浏览/下载：13/0 | 提交时间：2012/06/06

singularity analysis 5-DoF fully-symmetrical parallel manipulator

A new approach for the removal of mixed noise based on wavelet transform (EI CONFERENCE) 会议论文 OAI收割
ICO20: Remote Sensing and Infrared Devices and Systems, August 21, 2005 - August 26, 2005, Changchun, China
作者: Li Y.; Li Y.; Li Y.; Li Y.

收藏 | 浏览/下载：38/0 | 提交时间：2013/03/25

This paper proposed a new approach for the removal of mixed noise. There are many different ways in image denoising. Donoho et al have proposed a method for image de-noising by thresholding ambiguity is often resulted in determining the correspondence of a modulus maximum to a singularity. In the light and indeed we combine the merits of the two techniques to form a new approach for the removal of mixed noise. At first the application of their method to image denoising has been extremely successful. But the method of Donoho is based on the assumption that the type of noise is only additive Gaussian noise we used wavelet singularity detection (WSD) technique to analyze singularities of signal and noise. According to the characteristic that wavelet transform modulus maxima of impulse noise rapidly decreases as the scale increases in wavelet domain which is not successful for impulse noise. Mallat has also presented a method for signal denoising by discriminating the noise and the signal singularities through an analysis of their wavelet transform modulus maxima (WTMM). Nevertheless it can be accurately located with multiscale space by going through dyadic orthogonal wavelet transform and removed. Furthermore the Gaussian noise is also removed through a level-dependent thresholding algorithm the tracing of WTMM is not just tedious procedure computationally algorithm. The experimental results demonstrate that the proposed method can effectively detect impulse noise and remove almost all of the noise while preserve image details very well.

Singularity analysis of fine-tuning Stewart platform for large radio telescope using genetic algorithm 期刊论文 OAI收割
MECHATRONICS, 2003, 卷号: 13, 期号: 5, 页码: 413-425
作者: Su, YX; Duan, BY; Peng, B; Nan, RD

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Stewart platform mechatronics singularity analysis genetic algorithm large radio telescope

Potential inversion problems for coupled system of downgoing and upcoming one-way wave equations 期刊论文 OAI收割
JOURNAL OF COMPUTATIONAL MATHEMATICS, 1998, 卷号: 16, 期号: 6, 页码: 551-560
作者: Zhang, GQ; Dou, XL

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收藏 | 浏览/下载：22/0 | 提交时间：2018/07/30

2-D potential inversion wave splitting singularity analysis

Symmetries and similarity reductions of the dym equation 期刊论文 OAI收割
PHYSICA SCRIPTA, 1996, 卷号: 54, 期号: 5, 页码: 428-435
作者: Lou, SY; Lou, SY , NINGBO NORMAL COLL,INST MODERN PHYS,NINGBO 315211,PEOPLES R CHINA.

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收藏 | 浏览/下载：24/0 | 提交时间：2012/08/29

Partial-differential Equations Dym Korteweg-devries Hierarchy Harry Linear Evolution-equations Sawada-kotera Equation Recursion Operator Painleve Property Discrete Eigenfunctions Singularity Analysis Kdv Equation

SYMMETRIES AND LIE-ALGEBRAS OF THE HARRY-DYM HIERARCHY 期刊论文 OAI收割
CHAOS SOLITONS & FRACTALS, 1994, 卷号: 4, 期号: 10, 页码: 1961-1964
作者: LOU, SY

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收藏 | 浏览/下载：25/0 | 提交时间：2012/08/29

Partial-differential Equations Bi-hamiltonian Structure Painleve Property Singularity Analysis Evolution-equations Integrable Systems Recursion Operator Transformation Potentials