中国科学院机构知识库网格系统: 检索

Constant cyclotron line energy in Hercules X-1 - Joint Insight-HXMT and NuSTAR observations 期刊论文 OAI收割
Journal of High Energy Astrophysics, 2019, 卷号: 23, 页码: 29-32
作者: HXMT

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收藏 | 浏览/下载：50/0 | 提交时间：2022/02/08

Stars: neutron star Pulsars: binary(Her X-1) X-rays: stars Astrophysics - High Energy Astrophysical Phenomena Abstract: The long-term evolution of the centroid energy of the CRSF in Her X-1 is still a mystery. We report a new measurement from a campaign between Insight-HXMT and NuSTAR performed in February 2018. Generally, the two satellites show well consistent results of timing and spectral properties. The joint spectral analysis confirms that the previously observed long decay phase has ended, and that the line energy instead keeps constant around 37.5 keV after flux correction.

A unified gas-kinetic scheme for continuum and rarefied flows,direct modeling,and full Boltzmann collision term 会议论文 OAI收割
The 29th International Symposium on Rarefied Gas Dynamics, 中国陕西西安, 2014-07-13
作者: Liu C; Xu K(徐昆); Sun QH(孙泉华); Cai QD

收藏 | 浏览/下载：21/0 | 提交时间：2015/09/10

unified collision Boltzmann hydrodynamic instead Stokes scales Navier continuum contour

Design of the real-time autofocusing system for collimator with long focus length and large aperture (EI CONFERENCE) 会议论文 OAI收割
2011 International Academic Conference on Numbers, Intelligence, Manufacturing Technology and Machinery Automation, MAMT 2011, December 24, 2011 - December 25, 2011, Wuhan, China
作者: Zhang X.; Zhang X.; Zhang X.

收藏 | 浏览/下载：40/0 | 提交时间：2013/03/25

Large aperture collimator which has been widely used for calibrating and testing various optical devices plays an essential role in correlative laboratories. As being the basic testing and calibration equipment the large aperture collimator's accuracy should be much higher than the device under testing in order to ensure the accuracy of the measurement. However the process of adjusting the collimator is extremely complicated due to the collimator's large aperture and long focal length. So it is difficult to ensure the measurement's quality and easy to cause the system being vulnerable to the surrounding environment. One of the most common problems is defocus. In order to solve the problem above this issue presents a new type of autocollimator autofocusing system which uses pentaprism instead of using large-aperture plane mirror semiconductor lasers as light source and CCD sensor as receiver. The system is smaller lighter and more convenient when using. The computer simulation shows that the autofocusing system's resolution could reach the accuracy of 40m. If we use the relevant algorithms to execute the sub-pixel scanning the resolution could reach the accuracy of 10m. It shows that the system could satisfy the required testing precision of testing large aperture optical device.

The design of space scanning mirror control system based on optimal tracking controller (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Electrical Insulating Materials and Electrical Engineering, EIMEE 2012, May 25, 2012 - May 27, 2012, Shenyang, Liaoning, China
作者: Zhang P.

收藏 | 浏览/下载：19/0 | 提交时间：2013/03/25

Control system of space scanning mirror has high requirement of scanning accuracy. The use of optimal tracking controller simulation experiment of the control system based on optimal tracking controller is carried out. The simulation result instead of traditional PID controller the control system based on optimal tracking controller is designed in comparison with the system based on a PID controller can effectively improve the scanning accuracy of space scanning mirror control system. State space model of the control system is established shows that the scanning mirror control system using optimal tracking controller instead of PID controller has higher scanning accuracy and faster response. (2012) Trans Tech Publications Switzerland.

Modeling and variable structure control of a vehicle flexible manipulator (EI CONFERENCE) 会议论文 OAI收割
10th World Congress on Intelligent Control and Automation, WCICA 2012, July 6, 2012 - July 8, 2012, Beijing, China
作者: Wang Z.; Li Y.; Li Y.; Li Y.; Li Y.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

In this paper the mathematical modeling and the application of a new trajectory tracking control technique for hydraulic-driven rigid-flexible manipulator are concerned. To get a closer dynamic behavior of the real system both the flexible manipulator linkage and the actuator dynamics are considered. The exact dynamic model of flexible manipulator is derived using Lagrange principle and assumed modes method. The partial decoupled dynamic equation is derived using nonlinear decoupling feedback control method. The whole dynamic model is established by a driven Jacobin matrix which represents the coupling between hydraulic servo system and mechanical system. A variable structure controller with inverse dynamics is designed for trajectory tracking. To weaken the chattering of control signal saturation function is used to instead of sign function. The experimental results investigate the effectiveness of the proposed approaches. 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：23/0 | 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.

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：57/0 | 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).

An autostereoscopic projecting system based on parallax barrier and lenticular sheets (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Multimedia Technology, ICMT 2011, July 26, 2011 - July 28, 2011, Hangzhou, China
Kong L.; Jin G.; Zhong X.

收藏 | 浏览/下载：17/0 | 提交时间：2013/03/25

In order to realize autostereoscopic 3D projecting display with higher brightness and larger size a technique of autostereoscopic 3D projecting using parallax barriers and lenticular sheets is proposed.The parameter design of lenticular sheets and parallax barriers is investigated.First projection distance of projector array is confirmed according to eye's resolution then the strips' character of lenticular sheets is analysed by zemax in four-view situation thickness and parameters of strips of lenticular sheets are confirmed. Finally the width of slit and pitch and viewing distance and etc of parallax barriers are confirmed according to parameters of strips of lenticular sheets.Data analysis indicate that the brightness of our four-view image is increased three times because of using lenticular sheets instead of parallax barriers comparing with the autostereoscopic 3D projector using two parallax barriers plates.Parameters design of parallax barriers and lenticular sheets are finished the feasibility and advantages of the 3D display of projecting are confirmed theoretically. 2011 IEEE.

An efficient color transfer algorithm for recoloring multiband night vision imagery (EI CONFERENCE) 会议论文 OAI收割
Enhanced and Synthetic Vision 2010, April 6, 2010 - April 6, 2010, Orlando, FL, United states
作者: Xu S.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

A color transfer method is presented to give fused multiband nighttime imagery a natural daytime color appearance in a simple and efficient way. Instead of using the traditional nonlinear l space the proposed method transfers the color distribution of the target image (daylight color image) to the source image (fused multiband nighttime imagery) in the linear YCBCR color space. The YCBCR transformation is simpler and more suitable for image fusion compared to the l conversion. The YCBCR transformation can be extended into a general formalism. And the paper mathematically proves that for color transfer using color spaces conforming to this general YC BCR space framework can produce same recoloring results as using the YCBCR space. Experimental results demonstrate that the YCBCR based color transfer method works surprisingly well for transferring natural color characteristics of daylight color images to false color fused multiband nighttime imagery and moreover can also be successfully applied to recoloring a variety of color images. 2010 SPIE.

Restoration of an atmospherically blurred image based on physical model fusion approach (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.; Li J.; Li J.; Li J.; Wang Y.

收藏 | 浏览/下载：26/0 | 提交时间：2013/03/25

This paper proposes a new restoration method only using the single image information combining atmospheric physical model with fusion techniques to reduce the degradation of the image contrast in bad weather conditions caused by atmospheric aerosols such as haze and fog. The basic idea of this method is to utilize physics-based model method instead of multisensors to generate a serial of virtual images and then to fuse those virtual images into a high contrast image based on the wavelet fusion technique. In contrast to previous methods our restoration technique is not only independent on predicted structure distributions of scene reflectance or detailed knowledge about the particular weather condition but also adapt to the situation without a reference image or images with moving objects captured by a video camera. Experiments on different poorcontrast images demonstrate the availability of the proposed method in case of restoring the atmospherically blurred images. 2010 IEEE.