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Driving as well as on a Sunny Day? Predicting Driver’s Fixation in Rainy Weather Conditions via a Dual-Branch Visual Model

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IEEE/CAA Journal of Automatica Sinica 2022年第7期9卷 1335-1338页

作者： han tian Tao Deng Hongmei Yan MOE Key Laboratory for Neuroinformation the School of Life Science and TechnologyUniversity of Electronic Science and Technology of ChinaChengdu 610054China School of Information Science and Technology Southwest Jiaotong UniversityChengdu 611756China IEEE

Dear Editor,Traffic driving is a dynamic and complicated task in which drivers are required to pay close attention to the important targets or regions to maintain safe margins.Rainy weather conditions make it more challenging with factors such as low visibility,raindrops,pedestrian with umbrellas,wipers,etc.Studies showed that rainy condition affects driving safety significantly[1],[2].It is reported that,in raining weather condition,the odds for a fatal accident are 3.340 times higher on highways than on streets[3].An investigation of the relationship between rainfall and fatal crashes in Texas from 1994 to 2018 on fatality analysis reporting system(FARS)database illustrated that rain-related fatal crashes represented about 6.8%of the total fatal crashes on average,moreover,the proportion showed high variability at the annual,monthly,and hourly time scales[4].Therefore,raining is a complex and critical factor for road safety planning and management.In fact,the traffic environment is a dynamic scene with multiple sources of information,including important targets that are highly relevant to the current driving task as well as irrelevant targets that may distract the driving task[5].

关键词： driving Driver visibility

Cutting Force Fluctuation Suppression and Error Homogenization of Noncircular Gear Hobbing Based on the Tool Shifting Method

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Chinese Journal of Mechanical Engineering 2023年第4期36卷 167-179页

作者： Dazhu Li Jiang han Xiaoqing tian Lian Xia Institute of Artificial Intelligence Anhui Polytechnic UniversityWuhu 241000China CIMS Institute Hefei University of TechnologyHefei 230009China

The current research on noncircular hobbing mainly focuses on the linkage model and motion realization.However,the intermittent cutting characteristics of hobbing would increase uncertainties in the manufacturing process.In this paper,a hobbing machining model with tool-shifting characteristics was proposed to solve the problems of cutting force fluctuation and inconsistency of tooth profile envelope accuracy at different positions of the pitch curve in noncircular gear hobbing.Based on the unit cutting force coefficient method,the undeformed chip volume generated by interrupted cutting was used to characterize the fluctuation trend of the hobbing force.The fluctuation characteristics of the cutting force generated by different hobbing models were compared and analyzed.Using the equivalent gear tooth and hob slotting numbers,an analysis model of the tooth profile envelope error of the noncircular gear was constructed.Subsequently,the tooth profile envelope errors at different positions of the pitch curve were compared and analyzed based on the constructed model.The transmission structure of the electronic gearbox was constructed based on the proposed hobbing model,and the hobbing experiment was conducted based on the selfdeveloped noncircular gear CNC hobbing system.This paper proposes a hobbing method that can effectively suppress the fluctuation of the peak and whole circumference cutting force and reduce the maximum envelope error of the whole circumference gear teeth.

关键词： Noncircular gear Gear hobbing Cutting force Envelope error Machining model

Modelling and analysis of metal flowing behaviors in constraining ring rolling of tapered ring with thin wall and three high ribs

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Chinese Journal of Aeronautics 2023年第6期36卷 476-492页

作者： Lin HUA Duanyang tian Xinghui han Wuhao ZHUANG Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Hubei Longzhong Laboratory Xiangyang 441000China School of Automotive Engineering Wuhan University of TechnologyWuhan 430070China

Tapered ring with thin wall and three high ribs(TRTWTHR),showing complicated geometry(wall thickness is less than 4 mm and rib height exceeds 20 mm),is extensively utilized to fabricate the critical structural parts of aerospace equipment such as spacecraft cabin,rocket body and fuel tank because of light weight and high carrying capacity.How to fabricate TRTWTHR with high performance is a critical problem that aerospace area needs to solve.In this work,constraining ring rolling(CRR)technique is first adopted to form TRTWTHR.However.unreasonable metal streamlines(UMS)and uncoordinated growth of three ribs easily occur in CRR of TRTWTHR,which makes the forming quality of TRTWTHR difficult to be controlled.Faced with this difficulty,an analytical model that can predict UMS and the height of three ribs in CRR of TRTWTHR is established so as to guide the process design of CRR.Subsequently,the reliability of the established analytical model and the feasibility of CRR of TRTWTHR are confirmed by FE simulation and experiment.Then,using the established analytical model,the window of UMS occurring relevant to the tapered angle of TRTWTHR and the location of the rib of middle end is developed.Finally,three uncoordinated growth modes among three ribs are found when the width of three ribs is identical and UMS do not occur,and the mechanisms of three uncoordinated growth modes are revealed.

关键词： Analytical model Constraining ring rolling Growth of three ribs Metal streamlines Tapered ring with thin wall and three high ribs

An Overview of Stochastic Quasi-Newton Methods for Large-Scale Machine Learning

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Journal of the Operations Research Society of China 2023年第2期11卷 245-275页

作者： tian-De Guo Yan Liu Cong-Ying han School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 101408China School of Statistics and Data Science KLMDASRLEBPSand LPMCNankai UniversityTianjin 300071China

Numerous intriguing optimization problems arise as a result of the advancement of machine learning.The stochastic first-ordermethod is the predominant choicefor those problems due to its high efficiency.However,the negative effects of noisy gradient estimates and high nonlinearity of the loss function result in a slow convergence rate.Second-order algorithms have their typical advantages in dealing with highly nonlinear and ill-conditioning problems.This paper provides a review on recent developments in stochastic variants of quasi-Newton methods,which construct the Hessian approximations using only gradient information.We concentrate on BFGS-based methods in stochastic settings and highlight the algorithmic improvements that enable the algorithm to work in various scenarios.Future research on stochastic quasi-Newton methods should focus on enhancing its applicability,lowering the computational and storage costs,and improving the convergence rate.

关键词： Stochastic quasi-Newton methods BFGS Large-scale machine learning

An innovative constraining ring rolling process for manufacturing conical rings with thin sterna and high ribs

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Chinese Journal of Aeronautics 2022年第8期35卷 324-339页

作者： Duanyang tian Xinghui han Lin HUA Xuan HU Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070 China School of Automotive Engineering Wuhan University of TechnologyWuhan 430070China

Conical rings with thin sterna and high ribs(CRTSHR)are key bearing-load parts of aerospace equipment,which are required to be manufactured with high performance and efficiency.Traditional ring rolling is the most preferred method for manufacturing high-performance ring parts,but it can hardly achieve the forming of CRTSHR due to the extreme geometry of CRTSHR.To solve this difficulty,an innovative constraining ring rolling process(CRR)is proposed in this paper to manufacture CRTSHR.To evaluate the proposed CRR and reveal its deformation behaviors,a thermomechanical coupled FE model for CRR of CRTSHR is established.Then,the experiment for CRR of CRTSHR is performed on a modified ring rolling machine,which proves that CRR of CRTSHR is feasible and the established FE model is reliable.Based on the reliable FE model,the metal flow mode in deformed CRTSHR is analyzed,and the deformation characteristics such as the stress state,strain distribution and the evolution of power parameters in CRR of CRTSHR are revealed.Finally,the influences of key parameters such as the friction factor between ring and molds,the diameter of idle roll and the feed velocity of idle roll on CRR of CRTSHR are investigated by FE simulation.

关键词： Conical rings with thin sterna and high ribs Deformation characteristics FE simulation Metal flow Ring rolling

Vermicompost:In situ retardant of antibiotic resistome accumulation in cropland soils

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Journal of Environmental Sciences 2024年第7期141卷 277-286页

作者： Meirui Mu Fengxia Yang Bingjun han Guisheng tian Keqiang Zhang Agro-Environmental Protection Institute Ministry of Agriculture and Rural AffairsTianjin 300191China Key Laboratory of Low-carbon Green Agriculture in North China Ministry of Agriculture and Rural Affairs P.R.ChinaBeijing 10083China Wuxue City Agriculture and Rural Bureau Wuhan 435400China

The dissemination of antibiotic resistance genes(ARGs)in soil has become a global environmental issue.Vermicomposting is gaining prominence in agricultural practices as a soil amendment to improve soil quality.However,its impact on soil ARGs remains unclear when it occurs in farmland.We comprehensively explored the evolution and fate of ARGs and their hosts in the field soil profiles under vermicompost application for more than 3years.Vermicompost application increased several ARG loads in soil environment but decreased the high-risk bla-ARGs(bla_(ampC),bla_(NDM),and bla_(GES-1))by log(0.04-0.43).ARGs in soil amended with vermicompost primarily occurred in topsoil(approximately 1.04-fold of unfertilized soil),but it is worth noting that their levels in the 40-60 cm soil layer were the same or even less than in the unfertilized soil.The microbial community structure changed in soil profiles after vermicompost application.Vermicompost application altered the microbial community structure in soil profiles,showing that the dominant bacteria(i.e.,Proteobacteria,Actinobacteriota,Firmicutes)were decreased 2.62%-5.48%with the increase of soil depth.A network analysis further revealed that most of ARG dominant host bacteria did not migrate from surface soil to deep soil.In particular,those host bacteria harboring high-risk bla-ARGs were primarily concentrated in the surface soil.This study highlights a lower risk of the propagation of ARGs caused by vermicompost application and provides a novel approach to reduce and relieve the dissemination of ARGs derived from animals in agricultural production.

关键词： Vermicompost application Antibiotic resistance genes Vertical migration Soil profile Agricultural soils

Eu^(3+)-doped Bovine Serum Albumin-derived Carbon Dots for Ratiometric Fluorescent Detection of Tetracycline

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Journal of Analysis and Testing 2022年第4期6卷 365-373页

作者： tian-tian Zhang Zi-han Chen Guo-Yue Shi Min Zhang School of Chemistry and Molecular Engineering Shanghai Key Lab for Urban Ecological Processes and Eco-RestorationEast China Normal UniversityShanghai200241China

The abuse of antibiotics has become a global concern,thus it is significant to develop simple antibiotic assays.Herein,a novel type of lanthanide-doped bovine serum albumin(BSA)derived carbon dots(BCDs)dubbed Eu-BCDs has been unveiled for ratiometric fluorescent detection of tetracycline(TC),which was formed from the one-step hydrothermal reaction of Eu^(3+)and BSA.Upon challenge with TC,the blue fluorescence of Eu-BCDs at 448 nm was gradually quenched due to the internal filtration effect,while the characteristic red fluorescence of Eu^(3+)at 618 nm was significantly enhanced owning to the antenna effect,leading to the ratiometric fluorescent detection of TC with fast response(2 min),a wide linear dynamic range(0-80μmol/L),and high selectivity and sensitivity(limit of detection(LOD)of 3 nmol/L).Moreover,Eu-BCDs can be successfully applied for the ratiometric fluorescent detection of TC in environmental and biological samples,such as river water,milk,honey and serum.The Eu-BCDs sensing platform would have great application potential in view of its simple preparation,rapid response,high sensitivity and good selectivity.

关键词： carbon dots Europium ion Ratiometric fluorescence Tetracycline

Estimation of buoy drifting based on adaptive parameter-varying time scale Kalman filter

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Journal of Control and Decision 2021年第3期8卷 353-362页

作者： han Xue tian Chai School of Navigation Jimei UniversityXiamenPeople’s Republic of China National and local joint engineering research center of ship aided navigation technology Jimei UniversityXiamenPeople’s Republic of China Fujian Shipping Research Institute Jimei UniversityXiamenPeople’s Republic of China Xiamen southeast International Shipping Research Center Jimei UniversityXiamenPeople’s Republic of China

To solve Kalman filter with dynamic time scale problem,an adaptive parameter-varying time scale kalman filter(APVTS-KF)is designed.An adaptive mechanism for choosing the covariance of state noise is designed.APVTS-KF is used to estimate the buoy drifting trajectory with different report intervals.Position drifting data of four buoys are used to test the proposed algorithm.The influence of report interval,drifting distance,adaptive factor and noise covariance are analysed and compared.The experimental results and error analysis show that APVTS-KF is better than other algorithms in trajectory estimation.Thus,Kalman filtering can be used for accurate trajectory estimation in the actual situation of buoy drifting with dynamic time intervals.

关键词： Kalman filter buoy drift state estimation

Raindrop Size Distribution Measurements at High Altitudes in the Northeastern Tibetan Plateau during Summer

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Advances in Atmospheric Sciences 2023年第7期40卷 1244-1256页

作者： Huibang han Yuxin ZhanG Jianbing tian Xiaoyan KANG Meteorological Disaster Prevention Technology Center in Qinghai Province Xining 810000China Key Laboratory for Disaster Prevention and Mitigation in Qinghai Province Xining 810000China

Characteristics of raindrop size distribution during summer are studied by using the data from six Parsivel disdrometers located in the northeastern Tibetan Plateau.The analysis focuses on convective and stratiform precipitation at high altitudes from 2434 m to 4202 m.The results show that the contribution of stratiform and convective precipitation with rain rate between 1≤Rhan that for stratiform precipitation.The droplet size spectra of both stratiform and convective precipitation shows a single peak with a peak particle size between 0.31–0.50 mm,and they have essentially the same peak particle size and number concentration at the same altitude.The maximum spectral widths of stratiform clouds are between 4 mm and 5 mm,while those of convective clouds range from 4 mm to 8 mm.The Gamma distribution is more suitable than the Marshall-Palmer distribution in terms of the actual raindrop spectrum distribution.The stratiform precipitation particles are smaller with higher number concentration,while the opposite is true for the convective precipitation particles.The convective precipitation particles drop faster than stratiform precipitation particles when the particle size exceeds 2 mm,and the falling velocity of raindrops after standard curve fitting is underestimated during the observation period.Moreover,conventional radar estimation methods would underestimate the precipitation in the Northeastern Tibetan Plateau.

关键词： raindrop size distribution precipitation microphysics Northeastern Tibetan Plateau fall velocity