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Outage Performance of Cognitive AF Relay Networks with Imperfect CSI Based on geometrical analysis

Chinese Journal of Electronics 2017年第5期26卷 1048-1056页

作者： LIU Shuai SUN Dechun LIU Zujun YI Kechu YANG Hong WANG Kan State Key Laboratory of Integrated Services Networks Xidian University China Academy of Space Technology

This paper studies the outage performance of a cognitive Amplify-and-forward(AF) relay network subject to Rayleigh *** the condition of imperfect Channel state information(CSI) estimations of the links from the secondary system to the Primary user(PU),the closed-form upper and lower bounds of the outage probability are derived through a geometrical analysis *** asymptotic analysis of the outage probability is also derived in the high Signal-to-noise ratio(SNR)regime to gain additional insights on the *** simulation results corroborate our theoretical analysis,and the effectiveness of the geometrical analysis method is verified with the conventional approach as a *** asymptotic results are very tight with the analytical lower bound in the high SNR *** also can be observed from the simulation results that the impact of the number of relays as well as the imperfect CSI on the outage probability and the diversity order.

关键词： Cognitive relay networks Imperfect Channel state information(CSI) geometrical analysis

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Efficient and accurate worm grinding of spur face gears according to an advanced geometrical analysis and a closed-loop manufacturing process

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Journal of Central South University 2022年第1期29卷 1-13页

作者： ZHOU Yuan-sheng TANG Zhong-wei SHI Xian-lin TANG Jin-yuan LI Zheng-min-qing State Key Laboratory of High Performance Complex Manufacturing Central South UniversityChangsha 410083China College of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China National Key Laboratory of Science and Technology on Helicopter Transmission Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Worm grinding has been applied to manufacture gears to pursue high accuracy and fine surface *** the worm used to grind face gears is manufactured with multi-axis computer numerical control(CNC)machining,the machining accuracy is usually improved by increasing the number of tool paths with more time ***,this work proposes a generated method to improve the efficiency by dressing the worm surface with only one path,and a closed-loop manufacturing process is applied to ensure the machining *** to an advanced geometric analysis,the worm surface is practically approximated as a swept surface generated by a planar ***,this curve is applied as the profile of a dressing wheel,which is used to dress the worm *** practical machining is carried out in a CNC machine tool,which was originally used to grind helical ***,a closed-loop manufacturing process including machining,measurement,and modification is proposed to compensate the machining *** proposed method is validated with simulations and practical experiments.

关键词： face gears worm grinding worm dressing geometrical analysis closed-loop manufacturing

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geometrical-analysis-Based Algorithm for Stereo Matching of Single-Lens Binocular and Multi-Ocular Stereovision System

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Journal of Electronic Science and Technology 2012年第2期10卷 107-112页

作者： Kah Bin Lim Wei Loon Kee the Department of Mechanical Engineering National University of Singapore

A geometrical analysis based algorithm is proposed to achieve the stereo matching of a single-lens prism based stereovision system. By setting the multi- face prism in frontal position of the static CCD （CM-140MCL） camera, equivalent stereo images with different orientations are captured synchronously by virtual cameras which are defined by two boundary lines： the optical axis and CCD camera field of view boundary. Subsequently, the geometrical relationship between the 2D stereo images and corresponding 3D scene is established by employing two fundamentals： ray sketching in which all the pertinent points, lines, and planes are expressed in the 3D camera coordinates and the rule of refraction. Landing on this relationship, the epipolar geometry is thus obtained by fitting a set of corresponding candidate points and thereafter, stereo matching of the prism based stereovision system is obtained. Moreover, the unique geometrical properties of the imaging system allow the proposed method free from the complicated camera calibration procedures and to be easily generalized from binocular and tri-oeular to multi-ocular stereovision systems. The performance of the algorithm is presented through the experiments on the binocular imaging system and the comparison with a conventional projection method demonstrates the efficient assessment of our novel contributions.

关键词： Epipolar line geometrical analysis prism single-lens stereo matching.

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A study on characteristics of tectonic block motion and tectonic setting of strong earthquakes in northern part of the Shanxi fault depression zone

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Acta Seismologica Sinica(English Edition) 2004年第4期17卷 417-425页

作者： YU Shen-e(于慎谔) Institute of Crustal Dynamics China Earthquake Administration Beijing 100085 China

This paper makes a systematical study on characteristics of structure and motion of the tectonic blocks in northern part of the Shanxi fault depression zone by means of geometrical and kinematical analysis of the blocks. The ki-netic behavior of the blocks is discussed by comparing associated geomorphic features of fault movement. All analyses and studies are based on a Domino model. The block movement, fault basin extension and their regional distribution are systematically investigated. The result shows: (a) The studied region is divided into sub-regions by NW striking faults: the western, middle and eastern sub-region with crustal extension being 4.46 km, 2.80 km and 1.86 km, respectively. The extensional amount of each block in the region is estimated being generally about 1 km. The calculated result using the block motion model approximately fits the data of geologic survey. (b) Block kin-ematical features are obviously different between the northern and southern part, with the Hengshan block in be-tween, of the studied region. Moreover, the magnitude of the largest historical earthquake in the northern part is about 6, while that in the southern is 7. The faulted blocks in the northern sub-region show northwestward exten-sion, indicating a feature of extensional graben, while the blocks in the southern part manifest tilt motion, extend-ing southeastward, in the opposite sense of fault dipping. Additional tectonic stress generated by block rotation may be one of major factors affecting seismogenic process in the region. It is responsible for the difference in the movement of the block boundary faults and seismic activities between the two sub-regions.

关键词： Shanxi fault depression zone block motion geometrical analysis

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