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A Novel Salient Region Detection Method Based on Hierarchical Spatial Information

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Chinese Journal of Electronics 2017年第2期26卷 319-324页

作者： liU Shuo DING Wenrui li hongguang li Yingting School of Electronic and Information Engineering Beihang University Research Institute of Unmanned Aerial Vehicle Beihang University

Different patterns in one object will cause unequal saliency degree which makes it hard to highlight the object region *** propose a salient region detection method which mainly includes image abstraction,saliency calculation and *** the detection framework,the hierarchical spatial information is introduced to improve the *** image abstraction with "pixel level" spatial information is applied to capture some meaningful *** local contrast is calculated with the "element level" spatial ***"object level" spatial information is represented as compactness and background possibility,which further help to better pop out the object region and suppress the *** results show that our method has a good performance even though the object consists of complex patterns.

关键词： Salient region detection Hierarchical spatial information Compactness Background possibility

Modelica-based Object-orient Modeling of Rotor System with Multi-Faults

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Chinese Journal of Mechanical Engineering 2013年第6期26卷 1169-1181页

作者： li Ming WANG Yu li Fucai li hongguang MENG Guang State Key Laboratory of Mechanical System and Vibration Shanghai Jiaotong University

Modelica-based object-orient method is proved to be rapid, accurate and easy to modify, which is suitable for prototype modeling and simulation of rotor system, whose parameters need to be modified frequently. Classical non-object-orient method appears to be inefficient because the code is difficult to modify and reuse. An adequate library for object-orient modeling of rotor system with multi-faults is established, a comparison with non-object-orient method on Jeffcott rotor system and a case study on turbo expander with multi-faults are implemented. The relative tolerance between object-orient method and non-object-orient is less than 0.03%, which proves that these two methods are as accurate as each other. Object-orient modeling and simulation is implemented on turbo expander with crack, rub-impact, pedestal looseness and multi-faults simultaneously. It can be conclude from the case study that when acting on compress side of turbo expander separately, expand wheel is not influenced greatly by crack fault, the existence of rub-impact fault forces expand wheel into quasi-periodic motion and the orbit of expand wheel is deformed and enhanced almost 1.5 times due to pedestal looseness. When acting simultaneously, multi-faults cannot be totally decomposed but can be diagnosed from the feature of vibration. Object-orient method can enhance the efficiency of modeling and simulation of rotor system with multi-faults, which provides an efficient method on prototype modeling and simulation.

关键词： rotor system multi-faults object-orient modeling Modelica

UAV image target localization method based on outlier filter and frame buffer

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Chinese Journal of Aeronautics 2024年第7期37卷 375-390页

作者： Yang WANG hongguang li Xinjun li Zhipeng WANG Baochang ZHANG Institute of Unmanned System Beihang UniversityBeijing 100191China School of Electronics and Information Engineering Beihang UniversityBeijing 100191China Institute of Artificial Intelligence Beihang UniversityBeijing 100191China

With rapid development of UAV technology,research on UAV image analysis has gained *** the existing techniques of UAV target localization often rely on additional equipment,a method of UAV target localization based on depth estimation has been ***,the unique perspective of UAVs poses challenges such as the significant field of view variations and the presence of dynamic objects in the *** a result,the existing methods of depth estimation and scale recovery cannot be directly applied to UAV ***,there is a scarcity of depth estimation datasets tailored for UAV perspectives,which makes supervised algorithms *** address these issues,an outlier filter is introduced to enhance the applicability of depth estimation networks to target localization.A frame buffer method is proposed to achieve more accurate scale recovery,so as to handle complex scene textures in UAV *** proposed method demonstrates a 14.29%improvement over the *** with the average recovery results from UAV perspectives,the difference is only 0.88%,approaching the performance of scale recovery using ground truth ***,to overcome the limited availability of traditional UAV depth datasets,a method for generating depth labels from video sequences is *** to state-of-the-art methods,the proposed approach achieves higher accuracy in depth estimation and stands for the first attempt at target localization using image *** algorithm and dataset are available at https://***/uav-tan/uav-object-localization.

关键词： Object localization Deep learning Depth estimate Scale recovery Unmanned Aerial Vehicle(UAV)

Multi-block SSD based on small object detection for UAV railway scene surveillance

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Chinese Journal of Aeronautics 2020年第6期33卷 1747-1755页

作者： Yundong li Han DONG hongguang li Xueyan ZHANG Baochang ZHANG Zhifeng XIAO North China University of Technology Beijing 100144China Key Laboratory of Large Structure Health Monitoring and Control Shijiazhuang 050043China Unmanned System Research Institute Beihang UniversityBeijing 100083China Guangdong Provincial Key Laboratory of Computer Vision and Virtual Reality Technology Shenzhen Institutes of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100083China State Key Laboratory of Information Engineering in Surveying Wuhan UniversityWuhan 430079China

A method of multi-block Single Shot Multi Box Detector(SSD)based on small object detection is proposed to the railway scene of unmanned aerial vehicle *** address the limitation of small object detection,a multi-block SSD mechanism,which consists of three steps,is ***,the original input images are segmented into several overlapped ***,each patch is separately fed into an SSD to detect the ***,the patches are merged together through two *** the first stage,the truncated object of the sub-layer detection result is *** the second stage,a sub-layer suppression and filtering algorithm applying the concept of non-maximum suppression is utilized to remove the overlapped boxes of *** boxes that are not detected in the main-layer are *** addition,no sufficient labeled training samples of railway circumstance are available,thereby hindering the deployment of SSD.A two-stage training strategy leveraging to transfer learning is adopted to solve this *** deep learning model is preliminarily trained using labeled data of numerous auxiliaries,and then it is refined using only a few samples of railway scene.A railway spot in China,which is easily damaged by landslides,is investigated as a case *** results show that the proposed multi-block SSD method produces an overall accuracy of 96.6%and obtains an improvement of up to 9.2%compared with the traditional SSD.

关键词： Deep learning Multi-block Single Shot MultiBox Detector(SSD) Objection detection Railway scene Unmanned aerial vehicle remote sensing

Application of the quadrilateral area coordinate method:a new element for laminated composite plate bending problems

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Acta Mechanica Sinica 2007年第5期23卷 561-575页

作者： Song Cen Xiangrong Fu Yuqiu Long hongguang li Zhenhan Yao Department of Engineering Mechanics School of Aerospace Tsinghua University Beijing 100084 China College of Water Conservancy and Civil Engineering China Agriculture University Beijing 100083 China Department of Civil Engineering Tsinghua University Beijing 100084 China Failure Mechanics Laboratory Tsinghua University Beijing 100084 China

Recently, some new quadrilateral finite elements were successfully developed by the Quadrilateral Area Coordinate （QAC） method. Compared with those traditional models using isoparametric coordinates, these new models are less sensitive to mesh distortion. In this paper, a new displacement-based, 4-node 20-DOF （5-DOF per node） quadrilateral bending element based on the first-order shear deformation theory for analysis of arbitrary laminated composite plates is presented. Its bending part is based on the element AC-MQ4, a recent-developed high-performance Mindlin-Reissner plate element formulated by QAC method and the generalized conforming condition method; and its in-plane displacement fields are interpolated by bilinear shape functions in isoparametric coordinates. Furthermore, the hybrid post-rocessing procedure, which was firstly proposed by the authors, is employed again to improve the stress solutions, especially for the transverse shear stresses. The resulting element, denoted as AC-MQ4-LC, exhibits excellent performance in all linear static and dynamic numerical examples. It demonstrates again that the QAC method, the generalized conforming condition method, and the hybrid post-processing procedure are efficient tools for developing simple, effective and reliable finite element models.

关键词： Quadrilateral Area Coordinate (QAC) Finite element Laminated composite plate First-order shear deformation theory (FSDT) Hybrid post-processing procedure

A modeling approach for fuzzy programming with echelon form membership functions

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北京化工大学学报（自然科学版） 2018年第1期45卷 78-83页

作者： WEN Bo li hongguang CHEN XiaoChun College of Information Science & Technology College of Chemical Engineering Beijing University of Chemical Technology Beijing 100029 China

In order to solve fuzzy mathematical programming with soft constraints,the initial models must first be converted into crisp *** functions are employed to describe the fuzzy right-hand side parameters needed to achieve this *** some cases,echelon form membership functions(EFMFs)are required to depict the actual fuzzy ***,due to their discrete properties,fuzzy programming problems with such membership functions cannot be modeled by traditional *** by these challenges,this paper introduces a novel absolute value representation modeling approach to formulate fuzzy programming using *** approach can translate a discrete model to a continuous one which can then be easily ***,by means of a numerical example,the effectiveness of our new approach is demonstrated.

关键词： echelon form membership function fuzzy right-hand side absolute value representation

Network Sorting Algorithm of Multi-Frequency Signal with Adaptive SNR

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Journal of Beijing Institute of Technology 2018年第2期27卷 206-212页

作者： Xinyong Yu Ying Guo Kunfeng Zhang Lei li hongguang li Institute of Information and Navigation Air Force Engineering UniversityXi'an 710077China Science and Technology on Information Transmission and Dissemination in Communication Networks Laboratory Shijiazhuang 050081China

An signal noise ratio（ SNR） adaptive sorting algorithm using the time-frequency（ TF）sparsity of frequency-hopping（ FH） signal is proposed in this paper. Firstly,the Gabor transformation is used as TF transformation in the system and a sorting model is established under undetermined condition; then the SNR adaptive pivot threshold setting method is used to find the TF single source. The mixed matrix is estimated according to the TF matrix of single source. Lastly,signal sorting is realized through improved subspace projection combined with relative power deviation of source. Theoretical analysis and simulation results showthat this algorithm has good effectiveness and performance.

关键词： frequency-hopping(FH) under-determined adaptive signal noise ratio(SNR) time-frequency(TF) signal source network sorting

Phase behavior and properties of salt-free cationic/anionic surfactant mixtures of oleic acid and stearic acid

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Chinese Science Bulletin 2009年第21期54卷 3953-3957页

作者： ZHAO DianYing li hongguang SONG AiXin HAO JingCheng Key Laboratory of Colloid and Interface Chemistry Ministry of Education Shandong University Jinan 250100 China Weifang Vocational College Weifang 261041 China

Cationic base surfactant, tetradecyltrimethylammonium hydroxide (TTAOH), can be obtained through anion exchange from tetradecyltrimethylammonium bromide (TTABr). Salt-free cationic and anionic (catanionic) surfactant mixtures were studied by mixing TTAOH with oleic acid (OA) or stearic acid (SA) in water. The phase behavior of TTAOH/OA/H2O is compared with that of TTAOH/SA/H2O. It was found that the phase behavior of TTAOH/OA/H2O and TTAOH/SA/H2O system differs from each other due to the existence of the unsaturated double carbon bond (C=C) in OA. At fixed total surfactant concentration (25 mg/mL) of TTAOH/OA/H2O system at 25℃, one can observe an isotropic L1 phase, and a L1/Lα two-phase region with increasing OA content. The volume of top turbid Lα phase increases while the bottom phase changes gradually from transparently clear to a bit turbid until a single Lα-phase is reached. Finally at high OA concentration, excess OA is separated from the bulk aqueous solutions. TTAOH/SA/H2O system usually forms white precipitating at 25℃ due to the high chain melting temperature of SA. When heated to 60℃, however, the state of samples changes. At fixed total surfactant concentration of 25 mg/mL, an isotropic L1 phase and a milk-white or bluish Lα-phase are observed with increasing SA concentration. Transparent thin layers which are strongly birefringent form at the tops of some samples within the Lα-phase region. Finally, at high SA concentration, excess SA is separated from the bulk aqueous solutions. In addition to phase behavior study, we also measured the conductivity of TTAOH/OA/H2O system at 25℃ and TTAOH/SA/H2O system at 60℃, respectively. Surface tension and rheological measurements were also performed on typical samples.

关键词：阴离子表面活性剂混合酸硬脂酸阳离子相行为油酸性能盐

Chiral metal nanocluster within nanoarchitecture of fullerene C_(60):Chirality transfer and improvement of nonlinear optical property

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Nano Research 2024年第11期17卷 9255-9260页

作者： Jinrui li Yuting Bi Ziyao liu Zhijie Yang Xia Xin Lei Feng hongguang li Jingcheng Hao Key Laboratory of Colloid and Interface Chemistry(Ministry of Education) School of Chemistry and Chemical EngineeringShandong UniversityJinan250100China

Interaction between heterogeneous,nanometer-sized building blocks(NSBBs)is fascinating from viewpoints of both structures and *** report the co-assembly of fullerene C_(60) and a chiral silver nanocluster(Ag_(6)),which yields C_(60) nanoarchitecture decorated with a small amount of Ag_(6).While Ag_(6) exhibits circular dichroism(CD)signal mainly in the ultraviolet(UV)region,the signal of the C_(60)-Ag_(6) hybrid extends to visible region(over 700 nm).Up to five pairs of CD signals were distinguished,which match well with the absorption of the C_(60) *** successful chirality transfer from the guest of Ag_(6) to C_(60)-dominated supramolecular system indicates that the“sergeants and soldiers”effect is valid in architectonics of *** addition,the doping of Ag_(6) leads to pronounced nonlinear optical response,paving a new way for the development of chiral optical materials.

关键词： chiral nanocluster fullerene chirality transfer nonlinear optical