中国科学院机构知识库网格系统: 检索

Synchronous X-ray/Optical QPOs from the Black Hole LMXB MAXI J1820+070 期刊论文 OAI收割
Monthly Notices of the Royal Astronomical Society, 2021
作者: HXMT

|

收藏 | 浏览/下载：59/0 | 提交时间：2022/02/08

black hole physics Low Mass X-ray Binaries accretion accretion discs stars: individual (MAXI J1820+070) Astrophysics - High Energy Astrophysical Phenomena Abstract: We present high-speed optical photometry from SAAO and SALT on the black hole LMXB MAXI J1820+070 (ASSASN-18ey), some of it simultaneous with NICER, Swift and Insight-HXMT X-ray coverage. We detect optical Quasi-Periodic Oscillations (QPOs) that move to higher frequencies as the outburst progresses, tracking both the frequency and evolution of similar X-ray QPOs previously reported. Correlated X-ray/optical data reveal a complex pattern of lags, including an anti-correlation and a sub-second lag that evolve over the first few weeks of outburst. They also show correlated components separated by a lag equal to the QPO period roughly centered on zero lag, implying that the inter-band variability is strongly and consistently affected by these QPOs at a constant phase lag of roughly ±Ю The synchronisation of X-ray and optical QPOs indicates that they must be produced in regions physically very close to each other we thus propose that they can be explained by a precessing jet model, based on analogies with V404 Cyg and MAXI J1348-630.

From quality to quantity: The role of common features in consumer preference 期刊论文 OAI收割
JOURNAL OF ECONOMIC PSYCHOLOGY, 2012, 卷号: 33, 期号: 6, 页码: 1043-1058
作者: Su, Yin; Rao, Li-Lin; Li, Xingshan; Wang, Yong; Li, Shu

收藏 | 浏览/下载：46/0 | 提交时间：2015/08/24

Common features Cancellation-and-focus model Equate-to-differentiate approach Eye-tracking Attribute-based strategies

Research on satellite platform vibration compensation method based on liquid crystal steering system (EI CONFERENCE) 会议论文 OAI收割
2011 SSITE International Conference on Future Material Research and Industry Application, FMRIA 2011, December 1, 2011 - December 2, 2011, Macau, China
作者: Wen M.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

This paper presents the disturbance compensation scheme based on liquid crystal steering system according to the problem that satellite platform vibration affects the tracking and pointing accuracy in space optical communication. The mathematical model of liquid crystal steering system is built. For improving convergence speed the adaptive controller based on posteriori estimation errors RLS lattice filter is designed which not only achieves fast adaptation but also reaches optimal steady-state disturbance compensation. Finally the simulation results show that this control scheme is valid and feasible. (2012) Trans Tech Publications Switzerland.

Analysis of zenith pass problem and tracking strategy design for roll-pitch seeker (EI CONFERENCE) 会议论文 OAI收割
作者: Jiang H.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

Roll-pitch seeker is currently applied in particular missiles. There is a stubborn problem called zenith pass problem while roll-pitch seeker is used. Analysis of the zenith pass problem which always results in loss of target is presented in this paper. Based on the analysis result tracking strategy is carried out to deal with zenith pass problem. To prove the validity of tracking strategy a practical roll-pitch seeker was accomplished. Model identification and common PID controllers for the physical roll-pitch seeker are taken on after that both disadvantages derived from zenith pass problem in tracking process and meliorated phenomenons by the tracking strategy are shown. It is concluded that the tracking strategy designed for solving the zenith pass problem is efficient. 2011 Elsevier Masson SAS. All rights reserved.

Trajectory tacking control of a quad-rotor based on active disturbance rejection control (EI CONFERENCE) 会议论文 OAI收割
2012 IEEE International Conference on Automation and Logistics, ICAL 2012, August 15, 2012 - August 17, 2012, Zhengzhou, China
Gong X.; Tian Y.; Bai Y.; Zhao C.

收藏 | 浏览/下载：36/0 | 提交时间：2013/03/25

The objective of this paper is to deal with a trajectory tracking of a Quad-rotor unmanned aerial vehicle (UAV). For the model uncertainty the external disturbance and the coupling factor are considered an active disturbance rejection control (ADRC) algorithm is introduced into the designing procedure. The aircraft dynamic model is proposed in this article based on which the closed-loop control system is divided into four independent channels with the coupling factor compensated by the extended state observer (ESO). The nonlinear state error feedback (NLSEF) algorithm is designed in each channel to improve the closed-loop dynamics. In this article the ADRC controller is expressed in the discrete form. And finally the simulation results show that the proposed control algorithm achieves a favourable tracking performance. 2012 IEEE.

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：20/0 | 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.

Trajectory tracking control for mobile robot based on the fuzzy sliding mode (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
Xie M.-J.; Li L.-T.; Wang Z.-Q.

收藏 | 浏览/下载：31/0 | 提交时间：2013/03/25

The trajectory tracking control problem of the uncertain mobile robot with nonholonomic constraints is analyzed. Sliding mode control is presented based on the kinematics models analysis. Switching function of sliding model control is designed according to back-stepping method. Trending law control is selected to improve the system dynamic performance. In order to solve the constant speed problem caused by conventional trending law control fuzzy control is used to adjust trending speed in the real time. The simulation results demonstrate that the fuzzy sliding mode controller improves the rapidity of trajectory tracking and reduces the tracking error and the chattering of the control output. 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：28/0 | 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.

任意手势的跟踪与识别技术研究 学位论文 OAI收割
工学硕士, 中国科学院自动化研究所: 中国科学院研究生院, 2011
石磊

收藏 | 浏览/下载：60/0 | 提交时间：2015/09/02

人机手势交互任意手势跟踪手势识别 SVM 隐马尔科夫模型 Gesture based Human Computer Interaction Arbitrary Hand-shape Tracking Hand Postures and Gestures Recognition Support Vector Machine Hidden Markov Model

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：63/0 | 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).