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Viewpoint Optimization Using Genetic Algorithm for Flying Robot Inspection of Electricity Transmission Tower Equipment

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Chinese Journal of Electronics 2014年第2期23卷 426-431页

作者： YANG Guotian dong ruifang WU Hua LIU Chang'an School of Control and Computer Engineering North China Electric Power University

To fully exploit the limited flight-time of the flying robot, and ensure the successful visibility of target, viewpoint optimization is proposed in this paper for the inspection of electricity transmission tower equipment with an optimization function to determine the best viewpoints in a local viewpoint region. The local viewpoint regions are generated from the local objective regions which are determined by the geometrical structure of a priori3 D model for the electricity transmission tower *** optimization function is structured based on three factors including visibility, viewing quality and observation distance. In addition, the fitness function of genetic algorithm is used to find the optimal viewpoint. The experimental results demonstrate the effectiveness and efficiency of the proposed viewpoint selection algorithm.

关键词： Flying robot inspection Electricity transmission tower equipment Viewpoint optimization Genetic algorithm 3D model

多传感器融合的SLAM算法在林业智能化的应用与改进

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东北林业大学学报 2025年第1期53卷 97-104页

作者：柳运昌韩军宇冯灵霄刘远航董蕊芳北京林业大学北京100083

同步定位与建图(SLAM)算法可实现机器人在未知环境下的定位,并对周围环境构建增量式地图,是机器人实现自主导航的基础。针对单一传感器(全球导航卫星系统(GNSS)、激光、相机等)的SLAM算法在林区环境存在定位精度低、构建的地图一致性较... 详细信息

同步定位与建图(SLAM)算法可实现机器人在未知环境下的定位,并对周围环境构建增量式地图,是机器人实现自主导航的基础。针对单一传感器(全球导航卫星系统(GNSS)、激光、相机等)的SLAM算法在林区环境存在定位精度低、构建的地图一致性较差的问题,提出了多传感器融合的SLAM算法在林业智能化的应用与改进。首先,联合使用激光雷达、单目相机、惯导对林区环境构建三维点云地图的同时对林业机器人进行实时定位;其次,提出以时间为约束的RS-T回环帧搜索法,进行候选回环帧搜索。结果表明:针对M2DGR数据集,RS-LVI-SAM算法与当前经典的SLAM算法对比,RS-LVI-SAM算法生成轨迹的均方根误差与标准差分别为0.09和0.04 m,定位精度最高;在林区场景中,RS-LVI-SAM算法建立的林区点云地图中侧柏的胸径与真实胸径的均方根误差与绝对平均误差分别为1.27、1.16 cm,建图效果最佳;生成的轨迹与真实轨迹的均方根误差与绝对平均误差分别为0.46、0.34 m,定位精度最高。因此,RS-LVI-SAM算法可以实现林区环境下的精准定位与林区点云地图构建,为机器人林区作业提供了技术支撑。

关键词：林业机器人同步定位与建图传感器激光雷达

Robust Transfer of Optical Frequency over 500km Fiber Link with Instability of 10^(−21)

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Chinese Physics Letters 2024年第8期41卷 22-27页

作者： Qian Zhou Xiang Zhang Qi Zang Mengfan Wu Dan Wang Jie Liu ruifang dong Tao Liu Shougang Zhang National Time Service Center Chinese Academy of SciencesXi’an 710600China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Time and Frequency Standards Chinese Academy of SciencesXi’an 710600China Hefei National Laboratory Hefei 230088China

Our primary objective is to mitigate the adverse effects of temperature fluctuations on the optical frequency transmission system by reducing the length of the *** optimization,the phase-temperature coefficient of the optical system is reduced to approximately 1.35 fs/*** applying a sophisticated temperature control to the remained“out-of-loop”optics fiber,the noise floor of the system has been effectively lowered to 10−21 *** on this performance-enhanced transfer system,we demonstrate coherent transmission of optical frequency through 500-km spooled fiber *** being actively compensated,the transfer instability of 4.5×10^(−16) at the averaging time of 1 s and 5.6×10^(−21) at 10000 s is *** frequency uncertainty of received light at remote site relative to that of the origin light at local site is achieved to be 1.15×10^(−19).This enhanced system configuration is particularly well suited for future long-distance frequency transmission and comparison of the most advanced optical clock signals.

关键词： fiber interferometer system

Surgical Management of Macular Epiretinal Membranes

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Eye Science 1996年第3期16卷 140-144页

作者： Fangtian dong, ruifang SuiChinese Acadamy of Medical Science, Peking Union Medical College Hospital, Beijing 100730, China Chinese Acadamy of Medical Science Perking Union Medical College Hospital Beijing China.

Purpose: To evaluate the effects of surgical treatment on macular epiretinal ***: Vitrectomy and membrane removal were undergone for idopathic or secondary macular epiretinal ***: Fourteen eyes of 15 patients (93%) had vision improvement after operation in which 8 eyes (57%) increased 3 or more Senellen lines. Only one case suffered from paracentral scotoma. No other complications were noted. Conclusion: Surgical management of macular epiretinal membrane is safe and effective with good visual outcome and few complications. Eye Science 1996; 12:140 -144.

关键词： epiretinal membrane macula vitrectomy

Coherent Optical Frequency Transfer via a 490 km Noisy Fiber Link

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Chinese Physics Letters 2022年第4期39卷 7-11页

作者： Xiang Zhang Xue Deng Qi Zang dongdong Jiao Jing Gao Dan Wang Qian Zhou Jie Liu Guanjun Xu ruifang dong Tao Liu Shougang Zhang National Time Service Center Chinese Academy of SciencesXi’an 710600China University of Chinese Academy of Sciences Beijing 100039China Key Laboratory of Time and Frequency Standards Chinese Academy of SciencesXi’an 710600China

We demonstrate the coherent transfer of an ultrastable optical frequency reference over a 490 km noisy field fiber *** fiber-induced phase noise power spectrum density per-unit-length at 1 Hz offset frequency can reach up to 510 rad^(2)·Hz^(-1)·km^(-1),which is much higher than the fiber noise observed in previous *** extreme level of phase noise is mainly due to the fiber link laying underground along the *** phaselocked loop parameters are chosen to complete the active compensation of fiber noise by measuring the intensity fluctuation of additional phase noise and designing a homemade digital frequency division phase discriminator with a large phase detection range of 2^(12)π***,a noise suppression intensity of approximately 40 d B at1 Hz is obtained,with fractional frequency instability of 1.1×10^(-14 )at 1 s averaging time,and 3.7×10^(-19) at10000 *** transfer system will be used for remote atomic clock comparisons and optical frequency distribution over a long-distance communication network established in China.

关键词： fiber noise underground

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某度假型酒店给排水系统设计重难点介绍

给水排水 2022年第3期48卷 98-102页

作者：董瑞芳科进柏诚工程技术(北京)有限公司北京100102

分析了某度假酒店给排水系统在设计过程中遇到的难点,重点就小市政排水方案、集中热水系统热源、别墅壁挂炉热水系统、集中热水系统分户计量等方面进行探讨,并提出设计中应关注的重点。

关键词：山地酒店小市政集中热水重难点

Surpassing the classical limit of the microwave photonic frequency fading effect by quantum microwave photonics

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Photonics Research 2023年第6期11卷 1094-1104页

作者： YAQING JIN YE YANG HUIBO HONG XIAO XIANG RUN'AI QUAN TAO LIU NINGHUA ZHU MING LI SHOUGANG ZHANG ruifang dong Key Laboratory of Time and Frequency Primary Standards National Time Service CenterChinese Academy of SciencesXi’an 710600China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory on Integrated Optoelectronics Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China School of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of SciencesBeijing 100049China The 29th Research Institute of China Electronics Technology Group Corporation Chengdu 610029China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100190China

With energy-time entangled biphoton sources as the optical carrier and time-correlated single-photon detection for high-speed radio frequency(RF)signal recovery,the method of quantum microwave photonics(QMWP)has presented the unprecedented potential of nonlocal RF signal encoding and efficient RF signal distilling from the dispersion interference associated with ultrashort pulse *** this paper,its capability in microwave signal processing and prospective superiority are further *** QMWP RF phase shifting and transversal filtering functionality,which are the fundamental building blocks of microwave signal processing,are *** good immunity to the dispersion-induced frequency fading effect associated with the broadband carrier in classical MWP,a native two-dimensional parallel microwave signal processor is *** results well demonstrate the superiority of QMWP over classical MWP and open the door to new application fields of MWP involving encrypted processing.

关键词： microwave quantum dispersion

Quantum microwave photonics in radio-over-fiber systems

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Photonics Research 2022年第7期10卷 1669-1678页

作者： YAQING JIN YE YANG HUIBO HONG XIAO XIANG RUNAI QUAN TAO LIU SHOUGANG ZHANG NINGHUA ZHU MING LI ruifang dong Key Laboratory of Time and Frequency Primary Standards National Time Service CenterChinese Academy of SciencesXi’an 710600China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory on Integrated Optoelectronics Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China The 29th Research Institute of China Electronics Technology Group Corporation Chengdu 610029China School of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of SciencesBeijing 100049China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100190China

As the main branch of microwave photonics,radio-over-fiber technology provides high bandwidth,low-loss,and long-distance propagation capability,facilitating wide applications ranging from telecommunication to wireless *** ultrashort pulses as the optical carrier,a large capacity is further ***,the wide bandwidth of ultrashort pulses results in the severe vulnerability of high-frequency radio frequency(RF)signals to fiber *** a time-energy entangled biphoton source as the optical carrier combined with the singlephoton detection technique,a quantum microwave photonics method in radio-over-fiber systems is proposed and demonstrated *** results show that it not only realizes unprecedented nonlocal RF signal modulation with strong resistance to the dispersion but also provides an alternative mechanism to distill the RF signal out from the dispersion ***,the spurious-free dynamic ranges of the nonlocally modulated and distilled RF signals have been significantly *** the ultra-weak detection and the high-speed processing advantages endowed by the low-timing-jitter single-photon detection,the quantum microwave photonics method opens new possibilities in modern communication and networks.

关键词： fiber ultrashort microwave

基于改进ORB_SLAM2的机器人视觉导航方法

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农业机械学报 2022年第10期53卷 306-317页

作者：董蕊芳王宇鹏阚江明北京林业大学工学院北京100083 林业装备与自动化国家林业和草原局重点实验室北京100083

提出了一种基于改进ORB_SLAM2的视觉导航方法。针对ORB_SLAM2构建的稀疏地图信息不充分、缺少占据信息、复用性差而无法直接用于导航的问题,对ORB_SLAM2算法进行了改进,融合环境的3D、2D占据特征以及路标点空间位置、视觉特征等多模态... 详细信息

提出了一种基于改进ORB_SLAM2的视觉导航方法。针对ORB_SLAM2构建的稀疏地图信息不充分、缺少占据信息、复用性差而无法直接用于导航的问题,对ORB_SLAM2算法进行了改进,融合环境的3D、2D占据特征以及路标点空间位置、视觉特征等多模态信息构建了包含定位、规划、交互图层的多图层地图以支撑机器人的精准定位和最优路径规划;针对机器人的自主导航任务,基于先验多图层地图建立约束进行机器人的位姿估计,融合运动约束进行机器人位姿优化,实现了基于先验地图的机器人精准定位,同时基于规划图层进行机器人的最优路径规划,提升了机器人的自主导航能力。在TUM数据集及北京鹫峰国家森林公园进行实验,结果表明:所构建的多图层地图提升了机器人定位的精度和效率,性能明显优于RGB-D SLAM;基于先验地图的视觉定位方法能够进行机器人移动过程中精准、实时地定位,助力机器人按照所规划的路径实现准确的自主导航。

关键词：机器人自主导航视觉SLAM 多图层地图先验地图路径规划