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浏览/检索结果: 共14条，第1-10条 帮助

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Variations of precipitation characteristics during the period 1960-2014 in the Source Region of the Yellow River, China 期刊论文  iSwitch采集
JOURNAL OF ARID LAND, 2018, 卷号: 10, 期号: 3, 页码: 388-401
作者:  Iqbal, Mudassar;  Wen Jun;  Wang Shaoping;  Tian Hui;  Adnan, Muhammad
收藏  |  浏览/下载：50/0  |  提交时间：2019/10/09
Combined effects of climate, restoration measures and slope position in change in soil chemical properties and nutrient loss across lands affected by the Wenchuan Earthquake in China 期刊论文  OAI收割
Science of the Total Environment, 2017, 卷号: 596-597, 页码: 274-283
作者:  Lin, Yongming
收藏  |  浏览/下载：35/0  |  提交时间：2017/05/08
Effects of alpine swamp wetland change on rainfall season runoff and flood characteristics in the headwater area of the Yangtze River SCI/SSCI论文  OAI收割
2015
作者:  Li J.;  Shi, W. J.
收藏  |  浏览/下载：29/0  |  提交时间：2015/12/09
Landslide Developmental Characteristics and Response to Climate Change since the Last Glacial in the Upper Reaches of the Yellow River, NE Tibetan Plateau 期刊论文  OAI收割
ACTA GEOLOGICA SINICA-ENGLISH EDITION, 2014, 卷号: 88, 期号: 2, 页码: 635-646
作者:  Yin Zhiqiang;  Qin Xiaoguang;  Yin Yueping;  Zhao Wuji;  Wei Gang
  |  收藏  |  浏览/下载：19/0  |  提交时间：2018/09/26
Landslide Developmental Characteristics and Response to Climate Change since the Last Glacial in the Upper Reaches of the Yellow River, NE Tibetan Plateau 期刊论文  OAI收割
ACTA GEOLOGICA SINICA-ENGLISH EDITION, 2014, 卷号: 88, 期号: 2, 页码: 635-646
作者:  Yin Zhiqiang;  Qin Xiaoguang;  Yin Yueping;  Zhao Wuji;  Wei Gang
  |  收藏  |  浏览/下载：32/0  |  提交时间：2018/09/26
Landslide Developmental Characteristics and Response to Climate Change since the Last Glacial in the Upper Reaches of the Yellow River, NE Tibetan Plateau 期刊论文  OAI收割
ACTA GEOLOGICA SINICA-ENGLISH EDITION, 2014, 卷号: 88, 期号: 2, 页码: 635-646
作者:  Yin Zhiqiang;  Qin Xiaoguang;  Yin Yueping;  Zhao Wuji;  Wei Gang
  |  收藏  |  浏览/下载：24/0  |  提交时间：2018/09/26
Three-loop autopilot design and simulation (EI CONFERENCE) 会议论文  OAI收割
2012 9th IEEE International Conference on Mechatronics and Automation, ICMA 2012, August 5, 2012 - August 8, 2012, Chengdu, China
作者:  Zhang Y.
收藏  |  浏览/下载：44/0  |  提交时间：2013/03/25
In order to realize missile real-time change flight trajectory  three-loop autopilot is setting up. The structure characteristics  autopilot model  and control parameters design method were researched. Firstly  this paper introduced the 11th order three-loop autopilot model. With the principle of systems reduce model order  the 5th order model was deduced. On that basis  open-loop frequency characteristic and closed-loop frequency characteristic were analyzed. The variables of velocity ratio  dynamic pressure ratio and elevator efficiency ratio were leading to correct system nonlinear. And then autopilot gains design method were induced. System flight simulations were done  and result shows that autopilot gains played a good job in the flight trajectory  autopilot satisfied the flight index. 2012 IEEE.  
The new approach for infrared target tracking based on the particle filter algorithm (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:  Sun H.;  Han H.-X.;  Sun H.
收藏  |  浏览/下载：59/0  |  提交时间：2013/03/25
Target tracking on the complex background in the infrared image sequence is hot research field. It provides the important basis in some fields such as video monitoring  precision  and video compression human-computer interaction. As a typical algorithms in the target tracking framework based on filtering and data connection  the particle filter with non-parameter estimation characteristic have ability to deal with nonlinear and non-Gaussian problems so it were widely used. There are various forms of density in the particle filter algorithm to make it valid when target occlusion occurred or recover tracking back from failure in track procedure  but in order to capture the change of the state space  it need a certain amount of particles to ensure samples is enough  and this number will increase in accompany with dimension and increase exponentially  this led to the increased amount of calculation is presented. In this paper particle filter algorithm and the Mean shift will be combined. Aiming at deficiencies of the classic mean shift Tracking algorithm easily trapped into local minima and Unable to get global optimal under the complex background. From these two perspectives that "adaptive multiple information fusion" and "with particle filter framework combining"  we expand the classic Mean Shift tracking framework.Based on the previous perspective  we proposed an improved Mean Shift infrared target tracking algorithm based on multiple information fusion. In the analysis of the infrared characteristics of target basis  Algorithm firstly extracted target gray and edge character and Proposed to guide the above two characteristics by the moving of the target information thus we can get new sports guide grayscale characteristics and motion guide border feature. Then proposes a new adaptive fusion mechanism  used these two new information adaptive to integrate into the Mean Shift tracking framework. Finally we designed a kind of automatic target model updating strategy to further improve tracking performance. Experimental results show that this algorithm can compensate shortcoming of the particle filter has too much computation  and can effectively overcome the fault that mean shift is easy to fall into local extreme value instead of global maximum value.Last because of the gray and fusion target motion information  this approach also inhibit interference from the background  ultimately improve the stability and the real-time of the target track. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).  
Theoretical analysis of emission characteristics of second-order distributed feedback semiconductor lasers (EI CONFERENCE) 会议论文  OAI收割
Semiconductor Lasers and Applications IV, October 18, 2010 - October 19, 2010, Beijing, China
作者:  Liu Y.;  Liu Y.;  Qin L.;  Liu Y.;  Wang L.
收藏  |  浏览/下载：24/0  |  提交时间：2013/03/25
Based on the modified coupled-wave theory  the emission characteristics  including threshold gain  photon density distribution in the cavity  and external differential quantum efficiency for second-order DFB lasers are investigated. Numerical simulation results show that for given device structure with wavelength of 1.55 m  the feedback coupling coefficient and the surface radiation coupling coefficient of the second-order grating have great influence on the emission characteristics of the device. By choosing different duty cycles of the grating  we can change the two coupling coefficients  which affect the emission characteristics. For an overall consideration  an optimal duty cycle of 0.43 is chosen. The optimized results show that the device works without degeneracy modes and spatial burning hole. Besides  the side-mode suppress ratio (SMSR) and external differential quantum efficiency reach as high as 42 dB and 47%  respectively. 2010 SPIE.  
Scene matching based on directional keylines and polar transform (EI CONFERENCE) 会议论文  OAI收割
2010 IEEE 10th International Conference on Signal Processing, ICSP2010, October 24, 2010 - October 28, 2010, Beijing, China
作者:  Wang Y.;  Wang Y.;  Wang Y.;  Wang Y.;  Wang Y.
收藏  |  浏览/下载：24/0  |  提交时间：2013/03/25
Scene matching under complex background is a priority and difficulty in the field of computer vision  it has the characteristics of rotation and scaling invariance  commonly used in matching real-time collected images and photos for navigation. Scene matching techniques are faced with complex natural scenes  anti-light and anti-slight-distortion  the image distortion exist  applicable for complex scene matching. The project has a new idea: combining the keylines with the vectors description based on polar image translation  such as light  and utilize the rotation-scale-invariance vectors to describe the extracted keylines  change of gray levels  this method includes three steps: keylines extraction  perspective  description and matching. Preliminary experiments show that this keylines-based scene matching algorithm is applicable for image matching under complex background. 2010 IEEE.  scaling and other differences  which cause matching difficult. This paper aims to find a scene matching algorithm