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Perception Enhanced Deep Deterministic Policy Gradient for Autonomous Driving in Complex Scenarios

Computer Modeling in Engineering & Sciences 2024年第7期140卷 557-576页

作者： Lyuchao Liao Hankun Xiao Pengqi Xing Zhenhua Gan Youpeng He jiajun wang Fujian Provincial Key Laboratory of Automotive Electronics and Electric Drive Fujian University of TechnologyFuzhou350118China Fujian Provincial Universities Engineering Research Center for Intelligent Driving Technology Fuzhou350118China

Autonomous driving has witnessed rapid advancement;however,ensuring safe and efficient driving in intricate scenarios remains a critical challenge.In particular,traffic roundabouts bring a set of challenges to autonomous driving due to the unpredictable entry and exit of vehicles,susceptibility to traffic flow bottlenecks,and imperfect data in perceiving environmental information,rendering them a vital issue in the practical application of autonomous driving.To address the traffic challenges,this work focused on complex roundabouts with multi-lane and proposed a Perception EnhancedDeepDeterministic Policy Gradient(PE-DDPG)for AutonomousDriving in the Roundabouts.Specifically,themodel incorporates an enhanced variational autoencoder featuring an integrated spatial attention mechanism alongside the Deep Deterministic Policy Gradient framework,enhancing the vehicle’s capability to comprehend complex roundabout environments and make decisions.Furthermore,the PE-DDPG model combines a dynamic path optimization strategy for roundabout scenarios,effectively mitigating traffic bottlenecks and augmenting throughput efficiency.Extensive experiments were conducted with the collaborative simulation platform of CARLA and SUMO,and the experimental results show that the proposed PE-DDPG outperforms the baseline methods in terms of the convergence capacity of the training process,the smoothness of driving and the traffic efficiency with diverse traffic flow patterns and penetration rates of autonomous vehicles(AVs).Generally,the proposed PE-DDPGmodel could be employed for autonomous driving in complex scenarios with imperfect data.

关键词： Autonomous driving traffic roundabouts deep deterministic policy gradient spatial attention mechanisms

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How the surface Cu layer affected the activity of Ni foil for alkaline hydrogen evolution

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Journal of Materials Science & Technology 2024年第2期169卷 11-18页

作者： Qingfeng Hu Yuan Liu Xuerong Zheng Jinfeng Zhang jiajun wang Xiaopeng Han Yida Deng Wenbin Hu School of Materials Science and Engineering Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of EducationTianjin UniversityTianjin 300072China State Key Laboratory of Marine Resource Utilization in South China Sea School of Materials Science and EngineeringHainan UniversityHaikou 570228China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityBinhai New CityFuzhou 350207China

Synthesizing bimetallic nanomaterials,with noble metals as the surface layers and inert metals as the substrates,has been proven to be an effective way to reduce the use of noble metals with maintained catalytic activity.However,an atomic diffusion from the inert substrate to the surface during the long-term operation has been reported to significantly decrease the activity.In this work,a series of catalysis-inert Cu-coated Ni foil were fabricated through electrodeposition and their activities for alkaline hydrogen evolution were investigated.Notably,the Ni/Cu-60 sample showed a similar catalytic property with pure Ni foil and only a slight decrease in HER activity was observed.The X-ray photoelectron spectroscopy(XPS)results indicated a decreased electron concentration of Cu in Ni/Cu-60,and theoretical calculations further demonstrated the electron transfer between the Ni substrate and Cu layer.Our results reveal that a specific composition or structure of an inert metal layer might not significantly decrease the electrocatalytic activity of active metals.Moreover,there are more possibilities for the rational design of metal-based catalysts for electrocatalysis.

关键词： Bimetallic heterostructure Charge redistribution Water splitting Alkaline hydrogen evolution

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Correlating the crystal structure and facet of indium oxides with their activities for CO_(2)electroreduction

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Fundamental Research 2024年第3期4卷 635-641页

作者： jiajun wang Guangjin wang Han Wu Fei Liu Xixi Ren Yidu wang Yanhui Cao Qi Lu Xuerong Zheng Xiaopeng Han Yida Deng Wenbin Hu School of Materials Science and Engineering Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of EducationTianjin UniversityTianjin 300072China School of Materials Science and Energy Engineering Foshan UniversityFoshan 528000China State Key Laboratory of Marine Resource Utilization in South China Sea School of Materials Science and EngineeringHainan UniversityHaikou 570228China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityBinhai New CityFuzhou 350207China

Constructing structure-function relationships is critical for the rational design and development of efficient catalysts for CO2 electroreduction reaction(CO2RR).In2O3 is well-known for its specific ability to produce formic acid.However,how the crystal phase and surface affect the CO_(2)RR activity is still unclear,making it difficult to further improve the intrinsic activity and screen for the most active structure.In this work,cubic and hexagonal In_(2)O_(3) with different stable surfaces((111)and(110)for cubic,(120)and(104)for hexagonal)are investigated for CO_(2)RR.Theoretical results demonstrate that the adsorption of reactants on cubic In_(2)O_(3) is stronger than that on hexagonal In_(2)O_(3),with the cubic(111)surface being the most active for CO_(2)RR.In experiments,synthesized cubic In_(2)O_(3) nanosheets with predominantly exposed(111)surfaces exhibited a high HCOO^(-)Faradaic efficiency(87.5%)and HCOO^(–)current density(–16.7 mA cm^(-2))at–0.9 V vs RHE.In addition,an aqueous Zn-CO_(2) battery based on a cubic In2O3 cathode was assembled.Our work correlates the phases and surfaces with the CO_(2)RR activity,and provides a fundamental understanding of the structure-function relationship of In_(2)O_(3),thereby contributing to further improvements in its CO_(2)RR activity.Moreover,the results provide a principle for the directional preparation of materials with optimal phases and surfaces for efficient electrocatalysis.

关键词： Structure-function relationship CO_(2)electroreduction Indium oxide Reactionmechanism Catalyst design

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Observation of accurately designed bound states in the continuum in momentum space

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Photonics Research 2024年第4期12卷 638-647页

作者： JIAJU WU JINGGUANG CHEN XIN QI ZHIWEI GUO jiajun wang FENG WU YONG SUN YUNHUI LI HAITAO JIANG LEI SHI JIAN ZI HONG CHEN MOE Key Laboratory of Advanced Micro-Structured Materials School of Physics Science and EngineeringTongji UniversityShanghai 200092China State Key Laboratory of Surface Physics Key Laboratory of Micro-and Nano-Photonic Structures(Ministry of Education)and Department of PhysicsFudan UniversityShanghai 200433China School of Optoelectronic Engineering Guangdong Polytechnic Normal UniversityGuangzhou 510665China

Bound states in the continuum(BICs)in artificial photonic structures have received considerable attention since they offer unique methods for the extreme field localization and enhancement of light-matter interactions.Usually,the symmetry-protected BICs are located at high symmetric points,while the positions of accidental BICs achieved by tuning the parameters will appear at some points in momentum space.Up to now,to accurately design the position of the accidental BIC in momentum space is still a challenge.Here,we theoretically and experimentally demonstrate an accurately designed accidental BIC in a two-coupled-oscillator system consisting of bilayer gratings,where the optical response of each grating can be described by a single resonator model.By changing the interlayer distance between the gratings to tune the propagation phase shift related to wave vectors,the position of the accidental BIC can be arbitrarily controlled in momentum space.Moreover,we present a general method and rigorous numerical analyses for extracting the polarization vector fields to observe the topological properties of BICs from the polarization-resolved transmission spectra.Finally,an application of the highly efficient second harmonic generation assisted by quasi-BIC is demonstrated.Our work provides a straightforward strategy for manipulating BICs and studying their topological properties in momentum space.

关键词： polarization tuning resonator

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Neurotoxicity of tetramethylammonium ion on larval and juvenile zebrafish:Effects on neurobehaviors and multiple biomarkers

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Journal of Environmental Sciences 2024年第9期143卷 138-147页

作者： Ruixin Zhang Rui wang jiajun Chang GDaniel Sheng Daqiang Yin Key Laboratory of Yangtze River Water Environment Ministry of EducationCollege of Environmental Science and EngineeringTongji UniversityShanghai 200092China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China

Tetramethylammonium hydroxide(TMAH)is an important compound that utilized and released by the rapidly expanding semiconductor industry,which could hardly be removed by the conventional wastewater treatment techniques.As a cholinergic agonist,the tetramethylammonium ion(TMA^(+))has been reported to induce toxicity to muscular and respiratory systems of mammals and human,however the toxicity on aquatic biota remains poorly known.We investigated the neurotoxic effects of TMA^(+)exposure on zebrafish,based on neurobehavior tests and a series of biomarkers.Significant inhibitions on the swimming distance of zebrafish larvae were observed when the exposure level exceeded 50 mg/L,and significant alterations on swimming path angles(straight and deflective movements)occurred even at 10 mg/L.The tested neurobehavioral endpoints of zebrafish larvae were significantly positively correlated with reactive oxygen species(ROS)and malondialdehyde(MDA),significantly negatively related with the activities of antioxidant enzymes,but not significantly correlated with the level of acetylcholinesterase(AChE).Such relationship indicates that the observed neurotoxic effects on swimming behavior of zebrafish larvae is mainly driven by oxidative stress,rather than the alterations of neurotransmitter.At the highest exposure concentration(200 mg/L),TMA^(+)evoked more severe toxicity on zebrafish juveniles,showing significantly stronger elevation on the MDA activity,and greater inhibitions on the activities of antioxidant enzymes and ACh E,suggesting juveniles were more susceptible to TMA^(+)exposure than larval zebrafish.

关键词： Tetramethylammonium Zebrafish Oxidative stress Acetylcholinesterase Neurobehavior

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Securing Forwarding Layers from Eavesdropping Attacks Using Proactive Approaches

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Computers, Materials & Continua 2024年第4期79卷 563-580页

作者： jiajun Yan Ying Zhou Anchen Dai Tao wang School of Electronics and Communication Engineering Sun Yat-sen UniversityShenzhen518107China

As an emerging network paradigm,the software-defined network(SDN)finds extensive application in areas such as smart grids,the Internet of Things(IoT),and edge computing.The forwarding layer in software-defined networks is susceptible to eavesdropping attacks.Route hopping is amoving target defense(MTD)technology that is frequently employed to resist eavesdropping attacks.In the traditional route hopping technology,both request and reply packets use the same hopping path.If an eavesdropping attacker monitors the nodes along this path,the risk of 100%data leakage becomes substantial.In this paper,we present an effective route hopping approach,called two-day different path(TDP),that turns communication paths into untraceable moving targets.This technology minimizes the probability of data leakage by transmitting request data and reply data through different paths.Firstly,a brief introduction to the network model and attack model involved in this paper is given.Secondly,the algorithm and processingmethod of the TDP are proposed.Thirdly,the paper proposes three differentmetrics tomeasure the effectiveness of the proposed approach.Finally,theoretical analysis and simulation results show that the TDP can effectively reduce the percentage of data exposure,decrease eavesdropping attack success probability,and improve the unpredictability of the path.

关键词： Route hopping moving target defense software-defined network two-way different path metrics

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How variable progenitor clones construct a largely invariant neocortex

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National Science Review 2024年第1期11卷 129-144页

作者： Zhongfu Shen jiajun Yang Qiangqiang Zhang Kuiyu wang Xiaohui Lv Xiaolin Hu Jian Ma Song-Hai Shi New Cornerstone Science Laboratory IDG/McG overn Institute for Brain Research Tsinghua-Peking Center for Life Sciences Beijing Frontier Research Center for Biological Structure School of Life Sciences Tsinghua University Department of Computer Sciences Tsinghua University College of Life Sciences Nankai University Chinese Institute for Brain Research

The neocortex contains a vast collection of diverse neurons organized into distinct layers. While nearly all neocortical neurons are generated by radial glial progenitors(RGPs), it remains largely unclear how a complex yet organized neocortex is constructed reliably and robustly. Here, we show that the division behavior and neuronal output of RGPs are highly constrained with patterned variabilities to support the reliable and robust construction of the mouse neocortex. The neurogenic process of RGPs can be well-approximated by a consistent Poisson-like process unfolding over time, producing deep to superficial layer neurons progressively. The exact neuronal outputs regarding layer occupation are variable; yet, this variability is constrained systematically to support all layer formation, largely reflecting the variable intermediate progenitor generation and RGP neurogenic entry and exit timing differences. Together, these results define the fundamental features of neocortical neurogenesis with a balanced reliability and variability for the construction of the complex neocortex.

关键词： neocortex radial glial progenitor intermediate progenitor neurogenesis clonal variability layer formation

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A Numerical Study on the Effect of the Backflow Hole Position on the Performances of a Self-Priming Pump

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Fluid Dynamics & Materials Processing 2024年第5期20卷 1103-1122页

作者： Dongwei wang Lijian Cao Weidong wang jiajun Hu School of Energy and Power Engineering Lanzhou University of TechnologyLanzhou730050China Sanlian Pump Industry Co. Ltd.Ma’anshan243000China

A self-priming pump is a centrifugal pump that has the ability to prime itself. Typically, its performance dependson the configuration of its reflux hole. In this study, the ANSYS FLUENT software is used to investigate the effectsof three different radial positions of the reflux hole on gas-liquid two-phase distribution, pressure pulsation, andimp during self-priming. The research results indicate that: (1) The effective channel size for the reflux liquid toenter the volute varies depending on the location of the reflux hole. The effect of the impeller rotation on thereflux liquid becomes more obvious as the setting distance of the reflux aperture decreases. (2) The position ofthe reflux hole significantly affects the gas phase mass fraction inside the impeller, resulting in a significant reductionin the time it takes for the mass fraction to exceed 80%. (3) The position of the reflux hole significantly affectsthe average pressure on each monitoring surface. (4) Placing the reflux hole at a excessively distant radial distancecan result in an excessive vertical component. (5) The self-priming performance of the pump can be improved tosome extent by placing the return hole at a small radial distance.

关键词： Self-priming pump self-priming time numerical calculation gas-liquid two-phase flow

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WeldNet:A voxel-based deep learning network for point cloud annular weld seam detection

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Science China(Technological Sciences) 2024年第4期67卷 1215-1225页

作者： wang Hui RONG YouMin XU jiajun XIANG SongMing PENG YiFan HUANG Yu State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China

Weld seam detection is an important part of automated welding.At present,few studies have been conducted on annular weld seams,and a lot of defects exist in the point cloud model of the tube sheet obtained by RGB-D cameras and photography methods.Aiming at the above problems,this paper proposed an annular weld seam detection network named WeldNet where a voxel feature encoding layer was adaptively improved for annular weld seams,the sparse convolutional network and region proposal network(RPN)were used to detect annular weld seam position,and an annular weld seam detection loss function was designed.Further,an annular weld seam dataset was established to train the network.Compared with the random sampling consistency(RANSAC)method,WeldNet has a higher detection accuracy,as well as a higher detection success rate which has increased by 23%.Compared with U-Net,WeldNet has been proven to achieve a better detection result,and the intersection over the union of the weld seam detection is improved by 17.8%.

关键词： deep learning point cloud weld seam detection welding annular weld seam

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High-efficiency nonlocal reflection-type vortex beam generation based on bound states in the continuum

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National Science Review 2023年第5期10卷 201-207页

作者： Tongyu Li jiajun wang Wenjie Zhang Xinhao wang Wenzhe Liu Lei Shi Jian Zi State Key Laboratory of Surface Physics Key Laboratory of Micro-and Nano-Photonic Structures (Ministry of Education) and Department of PhysicsFudan University Department of Physics The Hong Kong University of Science and Technology

Momentum-space polarization vortices centered at symmetry-protected bound states in the continuum of a periodic structure,e.***.photonic crystal slab,provide a novel nonlocal approach to generate vortex beams.This approach enjoys a great convenience of no precise alignment requirements,although the generation efficiency of the nonlocal generators requires further optimization before the practical application.In this work,we propose a temporal-coupled-mode-theory-based guideline for high-efficiency nonlocal reflection-type vortex generator design.The conversion efficiency of the vortex beam is found to be limited by the ratio of the radiative loss to the intrinsic absorption in practical systems.To increase this ratio through mode selection and structure design,the photonic crystal slabs are theoretically designed and experimentally characterized,showing a maximum on-resonance conversion efficiency of up to 86%.Combining high efficiency with simple fabrication and no re quirement for precise alignment,reflection-type photonic crystal slabs could offer a new and competitive way to generate vortex beams flexibly.

关键词： photonic crystal slab vortex beam bound states in the continuum

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