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Pyramid Bayesian Method for Model Uncertainty Evaluation of Semantic Segmentation in Autonomous Driving

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Automotive Innovation 2022年第1期5卷 70-78页

作者： Yang Zhao Wei Tian Hong Cheng School of Automation Engineering University of Electronic Science and Technology of ChinaChengduChina

With the fast-developing deep learning models in the field of autonomous driving,the research on the uncertainty estima-tion of deep learning models has also prevailed.Herein,a pyramid Bayesian deep learning method is proposed for the model uncertainty evaluation of semantic segmentation.Semantic segmentation is one of the most important perception problems in understanding visual scene,which is critical for autonomous driving.This study to optimize Bayesian SegNet for uncertainty evaluation.This paper first simplifies the network structure of Bayesian SegNet by reducing the number of MC-Dropout layer and then introduces the pyramid pooling module to improve the performance of Bayesian SegNet.mIoU and mPAvPU are used as evaluation matrics to test the proposed method on the public Cityscapes dataset.The experimental results show that the proposed method improves the sampling effect of the Bayesian SegNet,shortens the sampling time,and improves the network performance.

关键词： Semantic Segmentation Bayesian SegNet Uncertainty Evaluation

RGB Image‑ and Lidar‑Based 3D Object Detection Under Multiple Lighting Scenarios

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Automotive Innovation 2022年第3期5卷 251-259页

作者： Wentao Chen Wei Tian Xiang Xie Wilhelm Stork School of Automotive Studies Tongji UniversityShanghaiChina Karlsruhe Institute of Technology 76131 KarlsruheGermany

In recent years,camera-and lidar-based 3D object detection has achieved great progress.However,the related researches mainly focus on normal illumination conditions;the performance of their 3D detection algorithms will decrease under low lighting scenarios such as in the night.This work attempts to improve the fusion strategies on 3D vehicle detection accuracy in multiple lighting conditions.First,distance and uncertainty information is incorporated to guide the“painting”of semantic information onto point cloud during the data preprocessing.Moreover,a multitask framework is designed,which incorpo-rates uncertainty learning to improve detection accuracy under low-illumination scenarios.In the validation on KITTI and Dark-KITTI benchmark,the proposed method increases the vehicle detection accuracy on the KITTI benchmark by 1.35%and the generality of the model is validated on the proposed Dark-KITTI dataset,with a gain of 0.64%for vehicle detection.

关键词： 3D object detection Multi-sensor fusion Uncertainty estimation Semantic segmentation PointPainting

Supersonic flutter control and optimization of metamaterial plate

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Chinese Journal of Aeronautics 2021年第11期34卷 15-20页

作者： Wei Tian tian ZHAO Yingsong GU Zhichun YANG School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China

A metamaterial plate is designed by embedding a periodic array of local nonlinear resonators for its supersonic flutter control.Based on the von Karman large deformation theory and supersonic piston aerodynamic theory,the nonlinear aeroelastic equations of the metamaterial plate are obtained by using the Hamilton principle.The comparisons for aeroelastic behaviors of the metamaterial plate and pure plate show that the proposed metamaterial plate can lead to an enlarged flutter boundary and lower vibration amplitude.Furthermore,a parametric optimization strategy for local nonlinear resonators is proposed to improve the nonlinear flutter behaviors of the metamaterial plate,and a significant enhancement of passive control performance can be achieved through optimization design.The present study demonstrates that the design of the metamaterial plate can provide an effective approach and potential application for nonlinear flutter suppression of supersonic plate.

关键词： Local resonators Metamaterial plate Nonlinear aeroelastic responses Parametric optimization design Supersonic flutter control

Artificial intelligence in orthopedic surgery:current state and future perspective

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Chinese Medical Journal 2019年第21期132卷 2521-2523页

作者： Xiao-Guang Han Wei Tian Department of Spine Surgery Beijing Jishuitan HospitalBeijing 100035China Beijing Key Laboratory of Robotic Orthopedics Beijing 100035China.

Artificial intelligence(AI),first proposed by Prof.John McCarthy in 1956,aims to reproduce human intelligence using computers.Machine learning(ML)is a form of AI that uses computational algorithms that learn and improve with experience.[1]The two main forms of ML are supervised and unsupervised.In supervised ML,algorithms are given labeled data,which is used to predict disease outcomes in a new patient.In contrast,unsupervised ML is used to identify patterns without training;the algorithm learns the inherent structure of the data by searching for common characteristics.[1]

关键词： computer intelligence searching

Cyclodextrin-functionalized Ordered Porous Block Copolymer Films: Preparation and Property

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Chinese Journal of Polymer Science 2018年第1期36卷 34-42页

作者： Jing Dang Yuan-wei Su Wei Tian Ministry of Education Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions and Shaanxi Key Laboratory of Macromolecular Science and Technology School of Science Northwestern Polytechnical University

Ordered porous block copolymer films（PBCFs） have attracted much attention because of their potential applications in several fields. In this paper, we first reported a non-destructive, controllable, and efficient approach for preparation of β-cyclodextrin（β-CD）-functionalized PBCFs（β-CD-PBCFs）. The key point of the approach is to incorporate β-CD units into the hydrophilic segment of amphiphilic block copolymers before the preparation of films. β-CD-PBCFs with structural integrity and controllable pore parameters were fabricated through combining of self-assembly and breath figure methods. And then, the effective adsorption capacity of β-CD-PBCFs toward Congo red was confirmed through UV-Vis spectroscopy and was found to be affected by β-CD content and solution p H values. Adsorption kinetic results showed that the adsorption behavior of β-CD-PBCFs was consistent with the pseudo-second-order kinetic model and the chemisorption mechanism.

关键词： Porous block copolymer film β-Cyclodextrin Breath figure Self-assembly

Hydrophobic long alkyl chain organic cations induced 2D/3D heterojunction for efficient and stable perovskite solar cells

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Journal of Materials Science & Technology 2022年第29期124卷 243-251页

作者： Xiang He Min Wang Fengren Cao Wei Tian Liang Li School of Physical Science and Technology Center for Energy Conversion Materials and PhysicsJiangsu Key Laboratory of Thin FilmsSoochow UniversitySuzhou 215006China

Designing post-formed two-dimensional(2D)perovskite on the surface of three-dimensional(3D)perovskite with matched energy levels and high stability is crucial for improving the performance and stability of perovskite solar cells(PSCs).Herein,a long alkyl chain dodecylammonium bromide(DABr)was applied to react with excessive lead iodide(PbI_(2))on the grain boundary of metal halide perovskite preferentially,forming DA_(2)PbI_(4)(n=1)to constitute a clear 2D/3D heterojunction.The existence of heterojunction increases the intensity of the built-in electric field of the device to enhance carrier separation and extraction,and the amino group of dodecylammonium cation passivates defects,which jointly contribute to the improvement of the power conversion efficiency(PCE)from 20.35 to 21.81%.The long alkyl chain endows the 2D perovskite with good hydrophobic properties,improving the humidity and thermal stability of the device.The unencapsulated device can maintain 64%of its initial efficiency after 1065 h storage in ambient air.

关键词： Hydrophobic 2D/3D perovskite Heterojunction Solar cell Stability

A model for converting thermal analysis to volume fraction of high carbon bearing steels during low-temperature tempering

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Journal of Materials Science & Technology 2023年第5期136卷 212-222页

作者： Qinglong Liu Junyu tian Wenting wei The State Key Laboratory of Refractories and Metallurgy The Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of EducationWuhan University of Science and TechnologyWuhan 430081China School of Automotive Engineering Wuhan University of TechnologyWuhan 430070China Hubei Key Laboratory of Advanced Technology for Automotive Components(Wuhan University of Technology) Wuhan 430070China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan 430070China

Quantitative prediction of phase content is of great importance to control and optimize the heat treat-ment process of steels.In this work,a model for predicting the phase content of tempered high carbon steels was proposed by taking a martensitic 100Cr6 bearing steel as a model case.The microstructural transformations during tempering were studied using thermal analysis,transmission electron microscopy(TEM),and X-ray diffraction(XRD).Kinetics analysis of thermal evolution by employing the isoconver-sional method,and assisted by TEM and XRD characterization,were performed to quantitatively estimate the volume fractions of different phases after tempering.A series of isothermal tempering experiments were designed to verify the model.The predicted results were in good agreement with the experimental results of XRD and electrolytic extraction measurements.

关键词： Bearing steel Martensite tempering Retained austenite Thermal analysis Kinetics

Rapid and specific detection of norepinephrine via a “hunting-shooting” strategy

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Science China Chemistry 2023年第4期66卷 923-925页

作者： Qi-wei Zhang Yang tian Shanghai Key Laboratory of Green Chemistry and Chemical Processes Department of ChemistrySchool of Chemistry and Molecular EngineeringEast China Normal UniversityShanghai 200241China

Neurotransmitters are important endogenous chemicals in the central and sympathetic nervous system of organisms,which play an important role in maintaining physiological processes,such as the signaling,neuromodulation... 详细信息

关键词： metabolism endogenous sympathetic

A novel synthetic aperture radar scattering model for sea surface with breaking waves

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Acta Oceanologica Sinica 2022年第4期41卷 138-145页

作者： Xiaochen Wang Yuxin Hu Bing Han Wei Tian Chunhua Zhang Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China Key Laboratory of Technology in Geo-spatial Information Processing and Application System Chinese Academy of SciencesBeijing 100190China The box51111 Beijing 100190China

In this study a novel synthetic aperture radar(SAR)scattering model for sea surface with breaking waves is proposed.Compared with existing models,the proposed model considers an empirical relationship between wind speed and wave breaking scattering to present the contribution of wave breaking.Moreover,the scattering weight factor p,and wave breaking rate q,are performed to present the contribution of the quasi-specular scattering term,Bragg scattering term,and wave breaking scattering term to the total scattering from the sea surface.To explore the modeling accuracy of sea-surface scattering,a simulated normalized radar cross-section(NRCS)and measured NRCS are compared.The proposed model generated the simulated NRCS and a matching GF-3 dataset was used for the measured NRCS.It was revealed that the performance of the VV polarization of our model was much better than that of HH polarization,with a correlation of 0.91,bias of-0.14 dB,root mean square error(RMSE)of 1.26 dB,and scattering index(SI)of-0.11.In addition,the novel model is explored and compared with the geophysical model of CMODs and satellite-measured NRCS from GF-3 SAR wave mode imagery.For an incidence angle 40°–41°,the relationship between the NRCS and wind speed,relative wind direction is proposed.As with the SAR-measured NRCS,the performance of VV polarization was much better than HH polarization,with a correlation of 0.99,bias of-0.25 dB,RMSE of 0.64 dB,and SI of-0.04.

关键词： synthetic aperture radar scattering model sea surface wave breaking