Search

Your search keyword '"Xu, Xiangyang"' showing total 2,330 results
Start Over Author "Xu, Xiangyang" Search Limiters Peer Reviewed
2,330 results on '"Xu, Xiangyang"'

5. Development and Application of a Calculation Program for the Landing Distance of Civil Aircraft

Author

Xu, Xiangyang, Li, Liangxing, Teng, Yue, Xiang, Zutao, Shi, Huagang, Qu, Weicheng, Chen, Guannan, Li, Fujuan, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Hirche, Sandra, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Tan, Kay Chen, Series Editor, and Fu, Song, editor

Published
2024
Full Text
View/download PDF

8. DWRSeg: Rethinking Efficient Acquisition of Multi-scale Contextual Information for Real-time Semantic Segmentation

Author

Wei, Haoran, Liu, Xu, Xu, Shouchun, Dai, Zhongjian, Dai, Yaping, and Xu, Xiangyang

Subjects
Computer Science - Computer Vision and Pattern Recognition, Computer Science - Artificial Intelligence
Abstract

Many current works directly adopt multi-rate depth-wise dilated convolutions to capture multi-scale contextual information simultaneously from one input feature map, thus improving the feature extraction efficiency for real-time semantic segmentation. However, this design may lead to difficult access to multi-scale contextual information because of the unreasonable structure and hyperparameters. To lower the difficulty of drawing multi-scale contextual information, we propose a highly efficient multi-scale feature extraction method, which decomposes the original single-step method into two steps, Region Residualization-Semantic Residualization. In this method, the multi-rate depth-wise dilated convolutions take a simpler role in feature extraction: performing simple semantic-based morphological filtering with one desired receptive field in the second step based on each concise feature map of region form provided by the first step, to improve their efficiency. Moreover, the dilation rates and the capacity of dilated convolutions for each network stage are elaborated to fully utilize all the feature maps of region form that can be achieved.Accordingly, we design a novel Dilation-wise Residual (DWR) module and a Simple Inverted Residual (SIR) module for the high and low level network, respectively, and form a powerful DWR Segmentation (DWRSeg) network. Extensive experiments on the Cityscapes and CamVid datasets demonstrate the effectiveness of our method by achieving a state-of-the-art trade-off between accuracy and inference speed, in addition to being lighter weight. Without pretraining or resorting to any training trick, we achieve an mIoU of 72.7% on the Cityscapes test set at a speed of 319.5 FPS on one NVIDIA GeForce GTX 1080 Ti card, which exceeds the latest methods of a speed of 69.5 FPS and 0.8% mIoU. The code and trained models are publicly available.

Published
2022

9. Dynamic Analysis of Point Contact Gears with Circular-parabola Configuration Based on Adams Software

Author

Liang Dong, Jiang Peng, Li Ming, Xu Xiangyang, and He Zeyin

Subjects
Point contact, Gear with circular-parabola configuration, Dynamic, Contact stress, Virtual prototype, Mechanical engineering and machinery, TJ1-1570
Abstract

Taking the point contact gear with circular-parabola configuration as the research object, based on the Adams dynamic analysis software, dynamic characteristics and the variable law of tooth surfaces are studied in this study. Firstly, according to space meshing theory, tooth surfaces equation of the point contact gear with circular-parabola configuration is derived, and three-dimensional solid models of gear pairs are established by the given design parameters. Secondly, the virtual prototype of point contact gears with circular-parabola configuration is established utilizing Adams software. Through simulation process, variation law of normal contact force, circumferential force, radial force and axial force of the gear are discussed. Change law of normal contact force under the same parameters and working conditions are analyzed between the point contact gear with circular-parabola configuration and general involute helical gears. Influences of meshing stiffness on normal contact force of the gear are also discussed. Research results show that the dynamic performance of point contact gears with circular-parabola configuration is better than that of general involute helical gears under the same parameters and working conditions. Meshing stiffness has a certain influence on the dynamic performance of tooth surfaces. For a reasonable variable range, the transmission process will be more stable with the increase of the meshing stiffness. The study can provide a basis for the design of point contact gears with circular-parabola configuration.

Published
2024
Full Text
View/download PDF

21. Contact Characteristics Analysis of the Internal Meshing Gear Transmission Pair with Double Contact Points

Author

Liang Dong, Li Ming, Jiang Peng, Xu Xiangyang, and He Zeyin

Subjects
Double contact points, Internal meshing gear, Contact area, Tooth surface contact analysis, Contact stress, Mechanical engineering and machinery, TJ1-1570
Abstract

Aiming at the tooth profile contact problem of internal meshing gear transmission pairs with double contact points, the generation method of tooth profiles of the internal meshing gear transmission pair with double contact points is present. Based on Hertz contact theory, the mathematical model of instantaneous contact ellipse of tooth profiles is established and the equations of contact trajectory are also derived. The contact ellipse area of tooth surfaces of the gear pair with double contact points is solved by the numerical analysis method, and the influences of the design and tooth profiles parameters on the contact ellipse are discussed. Using the finite element analysis method, the contact ellipse area and tooth surface contact stress of the internal meshing gear pair with single contact point and double contact points are compared. The research conclusions show that the contact area location and size can be effectively controlled by selecting the suitable contact angle, nominal pressure angle, normal modulus and spiral angle. Under the same parameters, the contact area with double contact points is larger than that of a single contact point, and the contact stress is smaller. The relevant research has important theoretical significance and reference values for improving the contact characteristics and mechanical properties of the new internal meshing gear transmission.

Published
2023
Full Text
View/download PDF

42. No vortex in straight flows -- on the eigen-representations of velocity gradient

Author

Xu, Xiangyang, Xu, Zhiwen, Tang, Changxin, Zhang, Xiaohang, and Zou, Wennan

Subjects
Physics - Fluid Dynamics, 15A18, 15A23, 76M23, 76M27
Abstract

Velocity gradient is the basis of many vortex recognition methods, such as Q criterion, $\Delta$ criterion, $\lambda_{2}$ criterion, $\lambda_{ci}$ criterion and $\Omega$ criterion, etc.. Except the $\lambda_{ci}$ criterion, all these criterions recognize vortices by designing various invariants, based on the Helmholtz decomposition that decomposes velocity gradient into strain rate and spin. In recent years, the intuition of 'no vortex in straight flows' has promoted people to analyze the vortex state directly from the velocity gradient, in which vortex can be distinguished from the situation that the velocity gradient has couple complex eigenvalues. A specious viewpoint to adopt the simple shear as an independent flow mode was emphasized by many authors, among them, Kolar proposed the triple decomposition of motion by extracting a so-called effective pure shearing motion; Li et al. introduced the so-called quaternion decomposition of velocity gradient and proposed the concept of eigen rotation; Liu et al. further mined the characteristic information of velocity gradient and put forward an effective algorithm of Liutex, and then developed the vortex recognition method. However, there is another explanation for the increasingly clear representation of velocity gradient, that is the local streamline pattern based on critical-point theory. In this paper, the tensorial expressions of the right/left real Schur forms of velocity gradient are clarified from the characteristic problem of velocity gradient. The relations between the involved parameters are derived and numerically verified. Comparing with the geometrical features of local streamline pattern, we confirm that the parameters in the right eigen-representation based on the right real Schur form of velocity gradient have good meanings to reveal the local streamline pattern. Some illustrative examples from the DNS data are presented., Comment: 16 pages, 9 figures, 1 appendix

Published
2020

Catalog

Books, media, physical & digital resources
See catalog results