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Robust water hazard detection for autonomous off-road navigation

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第6期10卷 786-793页

作者： Tuo-zhong YAO zhi-yu xiang Ji-lin LIU Department of Information Science and Electronic Engineering Zhejiang University Hangzhou 310027 China

Existing water hazard detection methods usually fail when the features of water surfaces are greatly changed by the surroundings, e.g., by a change in illumination. This paper proposes a novel algorithm to robustly detect different kinds of water hazards for autonomous navigation. Our algorithm combines traditional machine learning and image segmentation and uses only digital cameras, which are usually affordable, as the visual sensors. Active learning is used for automatically dealing with problems caused by the selection, labeling and classification of large numbers of training sets. Mean-shift based image segmentation is used to refine the final classification. Our experimental results show that our new algorithm can accurately detect not only ‘common’ water hazards, which usually have the features of both high brightness and low texture, but also ‘special’ water hazards that may have lots of ripples or low brightness.

关键词： Water hazard detection Active leaming Adaboost Mean-shift

Vision based terrain reconstruction for planet rover using a special binocular bundle adjustment

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第10期9卷 1341-1350页

作者： Min-yi SHEN zhi-yu xiang Ji-lin LIU Institute of Information and Communication Engineering Zhejiang University Hangzhou 310027 China Zhejiang Provincial Key Laboratory of Information Network Technology Zhejiang University Hangzhou 310027 China

This paper presents a pure vision based technique for 3D reconstruction of planet terrain. The reconstruction accuracy depends ultimately on an optimization technique known as 'bundle adjustment'. In vision techniques, the translation is only known up to a scale factor, and a single scale factor is assumed for the whole sequence of images if only one camera is used. If an extra camera is available, stereo vision based reconstruction can be obtained by binocular views. If the baseline of the stereo setup is known, the scale factor problem is solved. We found that direct application of classical bundle adjustment on the constraints inherent between the binocular views has not been tested. Our method incorporated this constraint into the conventional bundle adjustment method. This special binocular bundle adjustment has been performed on image sequences similar to planet terrain circumstances. Experimental results show that our special method enhances not only the localization accuracy, but also the terrain mapping quality.

关键词： 3D reconstruction Binocular bundle adjustment (BBA) Scale-invariant feature transform (SIFT) Re-projectionerror RANSAC

Stereo vision based SLAM using Rao-Blackwellised particle filter

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第4期9卷 500-509页

作者： Er-yong WU Gong-yan LI zhi-yu xiang Ji-lin LIU Department of lnformation Science and Electrical Engineering Zhejiang University Hangzhou 310027 China National Laboratory of Pattern Recognition Institute of Automation CAS Beijing 100080 China

We present an algorithm which can realize mobile robot in unknown outdoor environments, which 3D stereo vision simultaneous localization and mapping （SLAM） for means the 6-DOF motion and a sparse but persistent map of natural landmarks be constructed online only with a stereo camera. In mobile robotics research, we extend FastSLAM 2.0 like stereo vision SLAM with ＂pure vision＂ domain to outdoor environments. Unlike popular stochastic motion model used in conventional monocular vision SLAM, we utilize the ideas of structure from motion （SFM） for initial motion estimation, which is more suitable for the robot moving in large-scale outdoor, and textured environments. SIFT features are used as natural landmarks, and its 3D positions are constructed directly through triangulation. Considering the computational complexity and memory consumption, Bkd-tree and Best-Bin-First （BBF） search strategy are utilized for SIFT feature descriptor matching. Results show high accuracy of our algorithm, even in the circumstance of large translation and large rotation movements.

关键词： Robot Vision based SLAM SIFT Feature management

“钢结构设计原理”课程教学新模式的探索与实践

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教育教学论坛 2024年第15期 81-84页

作者：余志祥陈景鑫张明西南交通大学土木工程学院四川成都610031

为响应《关于深化本科教育教学改革全面提高人才培养质量的意见》,提高本科教学质量,教学课题组探索了“钢结构设计原理”课程教学的新模式,即以线下教学为主,结合线上直播授课、网络教学平台以及QQ交流群内讨论答疑的方式开展课程教学... 详细信息

为响应《关于深化本科教育教学改革全面提高人才培养质量的意见》,提高本科教学质量,教学课题组探索了“钢结构设计原理”课程教学的新模式,即以线下教学为主,结合线上直播授课、网络教学平台以及QQ交流群内讨论答疑的方式开展课程教学,在尽可能给予学生最好的课堂学习体验的同时,也为他们提供优质的课后学习资料。线上与线下并行、理论与实践结合是该新模式探索的关键。此外,引入钢结构工程中蕴含的丰富的思政元素,综合提升学生的专业知识与思想品德素养。

关键词：本科教学新模式钢结构设计原理线上与线下并行教学网络教学平台 QQ交流群

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ANSYS辅助土木工程专业课程教学的思考

教育教学论坛 2024年第23期 9-12页

作者：余志祥刘楠枫张明西南交通大学土木工程学院四川成都610031

土木工程专业课程涉及面广,专业度高,其主要内容分为专业基础课和专业核心课两大类,涉及的专业术语多,前后课程关联性强,并要求学生在学习中能够将具体工程问题抽象为典型工程模型进行分析计算。ANSYS是一款集建模求解能力、非线性分析... 详细信息

土木工程专业课程涉及面广,专业度高,其主要内容分为专业基础课和专业核心课两大类,涉及的专业术语多,前后课程关联性强,并要求学生在学习中能够将具体工程问题抽象为典型工程模型进行分析计算。ANSYS是一款集建模求解能力、非线性分析能力、网格划分及优化能力、耦合分析能力为一体的有限元分析软件,在土木工程中被广泛运用。在土木工程专业课程中,利用ANSYS辅助分析工程问题,能使抽象模型直观化、复杂信息有序化、分析结果形象化,能够提高学生的学习兴趣和自主实践能力。

关键词： ANSYS 土木工程专业课程课程教学

PTCs promoted biphasic oxidation of ethylbenzene catalyzed by NHPI and CoSPc

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Chinese Chemical Letters 2012年第8期23卷 895-898页

作者： yu Lu Zhou Sha Sha Lin Dao Hong Xia yu zhi xiang College of Science State Key Laboratory of Heavy OilChina University of PetroleumQingdao 266580China

An easy workup and environmentally friendly method to convert ethylbenzene into the corresponding oxides, catalyzed by a combined catalytic system consisting of NHPI and CoSPc, was developed in a water involved liquid-liquid heterogeneous system. Experimental results showed that the reaction performed well facilitated by PTCs at multigrams material level, under which the conversion rate of ethylbenzene and the selectivity of acetophenone reached 60.6% and 95.2% after 0.5 h of reaction in oxygen atmosphere. An oxidation process was orooosed at the end of this oaoer.

关键词： Ethylbenzene Aerobic oxidation NHPI CoSPc PTC

Robust object tracking with RGBD-based sparse learning

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Frontiers of Information Technology & Electronic Engineering 2017年第7期18卷 989-1001页

作者： Zi-ang MA zhi-yu xiang College of Information Science and Electronic Engineering Zhejiang University Hangzhou 310027 China Zhejiang Provincial Key Laboratory of lnformation Network Technology Hangzhou 310027 China

Robust object tracking has been an important and challenging research area in the field of computer vision for decades. With the increasing popularity of affordable depth sensors, range data is widely used in visual tracking for its ability to provide robustness to varying illumination and occlusions. In this paper, a novel RGBD and sparse learning based tracker is proposed. The range data is integrated into the sparse learning framework in three respects. First, an extra depth view is added to the color image based visual features as an independent view for robust appearance modeling. Then, a special occlusion template set is designed to replenish the existing dictionary for handling various occlusion conditions. Finally, a depth-based occlusion detection method is proposed to efficiently determine an accurate time for the template update. Extensive experiments on both KITTI and Princeton data sets demonstrate that the proposed tracker outperforms the state-of-the-art tracking algorithms, including both sparse learning and RGBD based methods.

关键词： Object tracking Sparse learning Depth view Occlusion templates Occlusion detection

Hydrodynamic Performance of An Integrated System of Breakwater and A Multi-Chamber OWC Wave Energy Converter

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China Ocean Engineering 2024年第4期38卷 543-556页

作者： NING De-zhi ZHANG xiang-yu WANG Rong-quan ZHAO Ming State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China Dalian Key Laboratory of Offshore Renewable Energy Dalian University of TechnologyDalian 116024China School of Computing Engineering and MathematicsUniversity of Western SydneyPenrith NSW 2751Australia

A multi-chamber oscillating water column wave energy converter(OWC-WEC)integrated to a breakwater is *** hydrodynamic characteristics of the device are analyzed using an analytical model based on the linear potential flow theory.A pneumatic model is employed to investigate the relationship between the air mass flux in the chamber and the turbine *** effects of chamber width,wall draft and wall thickness on the hydrodynamic performance of a dual-chamber OWC-WEC are *** results demonstrate that the device,with a smaller front wall draft and a wider rear chamber exhibits a broader effective frequency *** device with a chamber-width-ratio of 1:3 performs better in terms of power ***,results from the analysis of a triplechamber OWC-WEC demonstrate that reducing the front chamber width and increasing the rearward chamber width can improve the total performance of the *** the number of chambers from 1 to 2 or 3 can widen the effective frequency bandwidth.

关键词： oscillating water column power extraction efficiency potential flow theory wave energy converter multi-chamber

Synthesis and self-association of dibenzothiophene derivatives for simulation of hydrogen bonding interaction in asphaltenes

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Petroleum Science 2015年第3期12卷 501-508页

作者： Ying-Hui Bian Shao-Tang Xu Le-Chun Song yu-Lu Zhou Li-Jun Zhu yu-zhi xiang Dao-Hong Xia State Key Laboratory of Heavy Oil Processing College of Chemical EngineeringChina University of Petroleum (East China)

The dibenzothiophene derivatives, namely 2-（dibenzothiophene-2-carbonyl）benzoic acid and 2-（diben- zothiophene-2-carbonyl）alkyl benzoate, were synthesized and characterized by nuclear magnetic resonance （1H NMR）, matrix-assisted laser desorption/ionization time of flight mass spectrometry, and elemental analysis. The self- association behavior of these dibenzothiophene derivatives in CH2C12 and CH3CN was investigated using UV-visible absorption spectroscopy, fourier transform infrared spec- troscopy, and atomic force microscopy. It was found that the carboxylic acid exhibited a strong self-association trend in CH2C12 solution at a concentration of about 5 × 10^-7 M. Hydrogen bonding of carboxyl in the dibenzoth- iophene derivatives was confirmed to be the main driving force for the formation of the carboxylic acid aggregates.

关键词： Dibenzothiophene derivatives Association Hydrogen bonding Simulation Asphaltenes