中国科学院机构知识库网格系统: 检索

Optical axis consistency alignment method for 1m-diameter solar telescope 会议论文 OAI收割
Shenzhen, China, 2023-08-04
作者: Xing, Fu; Lei, Yu; Bindong, Ji; Keiwei, E.

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收藏 | 浏览/下载：8/0 | 提交时间：2024/02/28

AIMS 1M solar telescope Computer-aided Alignment

Computer-aided alignment method for AIMS solar telescope 会议论文 OAI收割
Shanghai, China, 2021-10-28
作者: E., Kewei; Fu, Xin; Shen, Yuliang; Zhao, Jianke; Wang, Tao

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收藏 | 浏览/下载：36/0 | 提交时间：2022/03/18

Alignment Telescope AIMS Optical testing Sub-aperture testing

Comparison of simulated backgrounds with in-orbit observations for HE, ME, and LE onboard Insight-HXMT 期刊论文 OAI收割
Astrophysics and Space Science, 2020, 卷号: 365, 页码: 158
作者: HXMT

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收藏 | 浏览/下载：50/0 | 提交时间：2022/02/08

Insight-HXMT Geant4 simulation Background observation Astrophysics - Instrumentation and Methods for Astrophysics Abstract: Insight-HXMT, the first X-ray astronomical satellite in China, aims to reveal new sources in the Galaxy and to study fundamental physics of X-ray binaries from 1 to 250 keV. It has three collimated telescopes, the High Energy X-ray telescope (HE), the Medium Energy X-ray telescope (ME), and the Low Energy X-ray telescope (LE). Before the launch, in-orbit backgrounds of these three telescopes had been estimated through Geant4 simulation, in order to investigate the instrument performance and the achievement of scientific goals. In this work, these simulated backgrounds are compared with in-orbit observations. Good agreements are shown for all three telescopes. For HE, (1) the deviation of the simulated background rate after two years of operation in space is 5 % from the observation (2) the total background spectrum and the relative abundance of the 67 keV line show long-term increases both in simulations and observations. For ME, (1) the deviation of simulated background rate is within 15 % from the observation, and (2) there are no obvious long-term increase features in the background spectra of simulations and observations. For LE, the background level given by simulations is also consistent with observations. The consistencies of these comparisons validate that the Insight-HXMT mass model, i.e., space environment components and models adopted, physics processes selected, and detector constructions built, is reasonable. However, the line features at 7.5 and 8.0 keV, which are obvious in the observed spectra of LE, are not evident in simulations. This might result from uncertainties in the LE constructions.

An underlying clock in the extreme flip-flop state transitions of the black hole transient Swift J1658.2-4242 期刊论文 OAI收割
Astronomy and Astrophysics, 2020, 卷号: 641, 页码: A101
作者: HXMT

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收藏 | 浏览/下载：59/0 | 提交时间：2022/02/08

accretion accretion disks black hole physics X-rays: binaries time Astrophysics - High Energy Astrophysical Phenomena Abstract:
Aims: Flip-flops are top-hat-like X-ray flux variations, which have been observed in some transient accreting black hole binary systems, and feature simultaneous changes in the spectral hardness and the power density spectrum (PDS). They occur at a crucial time in the evolution of these systems, when the accretion disc emission starts to dominate over coronal emission. Flip-flops remain a poorly understood phenomenon, so we aim to thoroughly investigate them in a system featuring several such transitions.
Methods: Within the multitude of observations of Swift J1658.2-4242 during its outburst in early 2018, we detected 15 flip-flops, enabling a detailed analysis of their individual properties and the differences between them. We present observations by XMM-Newton, NuSTAR, Astrosat, Swift, Insight-HXMT, INTEGRAL, and ATCA. We analysed their light curves, searched for periodicities, computed their PDSs, and fitted their X-ray spectra, to investigate the source behaviour during flip-flop transitions and how the interval featuring flip-flops differs from the rest of the outburst.
Results: The flip-flops of Swift J1658.2-4242 are of an extreme variety, exhibiting flux differences of up to 77% within 100 s, which is much larger than what has been seen previously. We observed radical changes in the PDS simultaneous with the sharp flux variations, featuring transitions between the quasi-periodic oscillation types C and A, which have never been observed before. Changes in the PDS are delayed, but more rapid than changes in the light curve. Flip-flops occur in two intervals within the outburst, separated by about two weeks in which these phenomena were not seen. Transitions between the two flip-flop states occurred at random integer multiples of a fundamental period of 2.761 ks in the first interval and 2.61 ks in the second. Spectral analysis reveals the high and low flux flip-flop states to be very similar, but distinct from intervals lacking flip-flops. A change of the inner temperature of the accretion disc is responsible for most of the flux difference in the flip-flops. We also highlight the importance of correcting for the influence of the dust scattering halo on the X-ray spectra.

STEP Mission: Search for Terrestrial Exo-Planets 会议论文 OAI收割
European Planetary Science Congress 2013,, London, UK, 2013
Chen D.; Wu; J.; Li B.

收藏 | 浏览/下载：32/0 | 提交时间：2014/04/30

Search for Terrestrial Exo-Planest (hereafter STEP) mission is a latest advanced research project in Chinese Strategic Pioneer Program (SPP) on Space Science. STEP aims at the nearby earth-alike planets detection comprehensive research on the planetary system and some astrometry research with 0.5 uas precision in the space which will get the fruitful achievements in the exo-planetary and astrometry research fields. STEP will take the Space Astrometry technique in the optical band. The FOV is 0.44 degree based on 1.2m primary and focus length is 50m. The special metrology technique will be taken to reach 0.5 uas astrometry precision which will be idea for terrestrial exo-planets detection. The mission will take the L2 orbit.

A Japanese-specific allele in the GALNT11 gene 期刊论文 OAI收割
LEGAL MEDICINE, 2010, 卷号: 12, 期号: 4, 页码: 208-211
作者: Yuasa, Isao

收藏 | 浏览/下载：43/0 | 提交时间：2015/09/14

Ancestry-informative markers (AIMS) Genotyping Single nucleotide polymorphism (SNP) Population-specific Population study

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

An intelligent method for early design and decision of space payload (EI CONFERENCE) 会议论文 OAI收割
2010 1st IEEE International Conference on Progress in Informatics and Computing, PIC 2010, December 10, 2010 - December 12, 2010, Shanghai, China
作者: Han C.-S.; Wen M.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

This paper is concerned with the design and decision method of space payload in the early design phase. The objective is to develop a generalized intelligent framework to assist designers in designing space payload. A multi-level method is introduced which is based on the combination of case-based reasoning (CBR) multicriteria rough sets theory (MRST) and kernel-based self-organizing maps (KSOM). The first is CBR module which aims to help designers to obtain some similar cases of the new situation. The second is MRST module which can extract the decision rules of configuration seletion. The third is KSOM module which can reduce the variable range and design space of the space payload. The results demonstrate the effectiveness of the proposed design method. 2010 IEEE.

A segment detection method based on improved Hough transform (EI CONFERENCE) 会议论文 OAI收割
ICO20: Optical Information Processing, August 21, 2005 - August 26, 2005, Changchun, China
作者: Yao Z.-J.

收藏 | 浏览/下载：25/0 | 提交时间：2013/03/25

Hough transform is recognized as a powerful tool in shape analysis which gives good results even in the presence of noise and the disconnection of edge. However 3. applying the standard Hough transform equation to every point of the input image edge 4. according to the local threshold 6. merging the segments whose extreme points are near. Experiment results show the approach not only can recognize regular geometric object but also can extract the segment feature of real targets in complex environment. So the proposed method can be used in the target detection of complicated scenes traditional Hough transform can only detect the lines 2. quantizing the parameter space and extracting a group of maximums according to the global threshold eliminating spurious peaks which are caused by the spreading effects and will improve the precision of tracking. cannot give the endpoints and length of the line segments and it is vulnerable to the quantization errors. Based on the analysis of its limitations Hough transform has been improved in order to detect line segment feature of targets. The algorithm aims to avoid the loss of spatial information as well as to eliminate the spurious peaks and fix on the line segments endpoints accurately 5. fixing on the endpoints of the segments according to the dynamic clustering rule which can expediently be used for the description and classification of regular objects. The method consists of 6 steps: 1. setting up the image parameter and line-segment spaces

车型自动识别研究 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, 2003
李训青

收藏 | 浏览/下载：68/0 | 提交时间：2015/09/02

智能交通系统车牌定位车型识别候选区域 Intelligent Transportation System ITS vehicle card localization vehicle type recognition available brand aims