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Structured road-oriented motion planning and tracking framework for active collision avoidance of autonomous vehicles

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Science China(Technological Sciences) 2021年第11期64卷 2427-2440页

作者： ZHANG ZiWei zheng ling LI YiNong ZENG PengYun LIANG YiXiao College of Mechanical and Vehicle Engineering Chongqing UniversityChongqing 400030China State Key Laboratory of Mechanical Transmissions Chongqing UniversityChongqing 400044China Macro Net Communication Co. Ltd.Chongqing 400000China

This paper proposes a novel motion planning and tracking framework based on improved artificial potential fields(APFs) and a lane change strategy to enhance the performance of the active collision avoidance systems of autonomous vehicles on structured roads. First, an improved APF-based hazard evaluation module, which is inspired by discrete optimization, is established to describe driving hazards in the Frenet-Serret coordinate. Next, a strategy for changing lane is developed in accordance with the characteristics of the gradient descent method(GDM). On the basis of the potential energy distribution of the target obstacle and road boundaries, GDM is utilized to generate the path for changing lane. In consideration of the safety threats of traffic participants, the effects of other obstacles on safety are taken as additional safety constraints when the lane-changing speed profile for ego vehicles is designed. Then, after being mapped into the Cartesian coordinate, the feasible trajectory is sent to the tracking layer, where a proportional-integral control and model predictive control(PI-MPC) based coordinated controller is applied. Lastly, several cases composed of different road geometrics and obstacles are tested to validate the effectiveness of the proposed algorithm. Results illustrate that the proposed algorithm can achieve active collision avoidance in complex traffic scenarios.

关键词： autonomous vehicles motion planning structured road artificial potential fields collision avoidance

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Simulation and Analysis on Overtaking Safety Assistance System Based on Vehicle-to-Vehicle Communication

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Automotive Innovation 2018年第2期1卷 158-166页

作者： Chunmei Mo Yinong Li ling zheng College of Automotive Engineering Chongqing UniversityChongqing 400044China

Because of the complexity and variability of an intelligent vehicle’s driving environment,it is difficult for the application of the vehicular sensors to meet the needs of the surrounding environment information ***-to-vehicle(V2V)communication technology is used by target vehicles to exchange information,and obtain the driving condition and driving intention of the front *** obtain environmental information outside the range of vehicular sensors in advance,in this paper,a vehicle overtaking assistance system is proposed based on V2V *** data,including the speed,position,direction angle and steering angle obtained using V2V communication,were preliminarily ***,combined with an overtaking safety distance model,the vehicle parameters,driver’s driving intention and vehicle status information were entered into an overtaking security assistance system to determine the overtaking *** theory was used to control the parameters of the overtaking safety distance ***,the overtaking safety assistance system was established and the proposed algorithm was tested using PreScan/MATLAB cooperative simulation *** results showed that the proposed overtaking safety algorithm effectively provided a warning according to environmental change and the driver’s intention,which assisted the driver to overtake and avoid the occurrence of accidents,which improved the safety performance of the vehicle.

关键词： V2V communication network Overtaking assistance Safe distance Active safety

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Interannual variability of thermal front west of Luzon Island in boreal winter

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Acta Oceanologica Sinica 2015年第11期34卷 102-108页

作者： SUN Ruili ling zheng CHEN Changlin YAN Yunwei College of Physical and Environmental Oceanography Ocean University of China State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyState Oceanic Administration

Interannual variability of thermal front west of Luzon Island during the winter of 1993-2013 is examined with the method of singular value decomposition （SVD） and a suite of satellite measurements in this paper. It is found that both the area and intensity of the thermal front west of Luzon Island show apparent interannual variability. Further study based on SVD shows that the interannual variability of the thermal front is highly associated with E1 Nifio and Southern Oscillation （ENSO）, and the correlation coefficient between Nifio3.4 index and the first Principal Component （PC1） of thermal front can reach -0.65. The mechanism can be described as follows. In E1 Nifio （La Nifia） years, the East Asian winter monsoon （EAWM） is weakened （enhanced）, inducing weaker （stronger） local wind stress curl （WSC） west of Luzon Island, and resulting in weakened （enhanced） Luzon cold eddy, which finally leads to the weakening （enhancement） of the thermal front.

关键词： thermal front interannual variability Luzon Island ENSO South China Sea

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Role of ocean upper layer warm water in the rapid intensification of tropical cyclones: A case study of typhoon Rammasun(1409)

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Acta Oceanologica Sinica 2016年第3期35卷 63-68页

作者： SUN Jia ZUO Juncheng ling zheng YAN Yunwei Key Laboratory of Coastal Disaster and Defence of Ministry of Education Hohai University Institute of Physical Oceanography Hohai University State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyState Oceanic Administration

Rammasun intensified rapidly from tropical storm to super typhoon in the northern South China Sea（NSCS）before its landfall on Hainan Island. Analysis of observed data shows that the anomalous ocean upper layer warm water（WW） is important to the rapid intensification of Rammasun. During the period of Rammasun, sea surface temperature（SST） in the NSCS was much warmer than the climatological SST. The anomalous WW supplied more energy to Rammasun, resulting in its rapid intensification. Numerical simulations further confirm that the NSCS WW plays an important role in the rapid intensification of Rammasun. As the WW is removed, the intensification of Rammasun is only 25 h Pa, which is 58.1% of that in the original SST-forced run.

关键词： tropical cyclone Rammasun rapid intensification warm water sea surface temperature

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Six types of spin solitons in three-component Bose-Einstein condensates

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Communications in Theoretical Physics 2024年第6期76卷 57-65页

作者： Yu-Hao Wang ling-zheng Meng Li-Chen Zhao School of Physics Northwest UniversityXi'an 710127China School of Science Xi'an Technological UniversityXi'an 710032China Peng Huanwu Center for Fundamental Theory Xi'an 710127China

Exact analytical solutions are good candidates for studying and explaining the dynamics of solitons in nonlinear *** further extend the region of existence of spin solitons in the nonlinearity coefficient space for the spin-1 Bose-Einstein *** types of spin soliton solutions can be obtained,and they exist in different *** analysis and numerical simulation results indicate that three types of spin solitons are stable against weak *** non-integrable properties of the model can induce shape oscillation and increase in speed after the collision between two spin *** results further enrich the soliton family for non-integrable models and can provide theoretical references for experimental studies.

关键词： Bose-Einstein condensate non-integrable spin soliton exact analytical solution

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A Lower Semicontinuity Result for Some Integral Functionals in the Space SBD

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Acta Mathematicae Applicatae Sinica 2008年第2期24卷 297-304页

作者： Zhong-xue Lu Xiao-ping Yang Min-ling zheng School of Mathematical Science Xuzhou Normal University Xuzhou 221116 China School of Science Nanjing University of Science and Technology Nanjing 210094 China School of Science Huzhou Teacher College Huzhou 313000 China

In this paper, we obtain a lower semicontinuity result with respect to the strong L1-convergence of the integral functionals F（u,Ω）=Ωf（x,u（x）,εu（x））dx defined in the space SBD of special functions with bounded deformation. Here Su represents the absolutely continuous part of the symmetrized distributional derivative Eu. The integrand f satisfies the standard growth assumptions of order p 〉 1 and some other conditions. Finally, by using this result,we discuss the existence of an constrained variational problem.

关键词： SBD space integral functionals lower semicontinuity

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Entropy of Dirac Field in Non-stationary and Slowly Changing Reissner-Nordstrom Black Hole

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Communications in Theoretical Physics 2005年第5X期44卷 955-960页

作者： LI Hui-ling YANG Shu-zheng JIANG Qing-Quan Institute of Theoretical Physics China West Normal University Nanchong 637002 China

Using the thin film brick-wall model and WKB approximation, the entropy of the Dirac field in the non-stationary and slowly changing Reissner-Nordstrom (R-N) black hole is calculated. The result shows that the entropy... 详细信息

关键词： slowly changing thin brick-wall model Dirac field entropy of black hole

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Effects of tidal currents on winter wind waves in the Qiongzhou Strait:a numerical study

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Acta Oceanologica Sinica 2020年第11期39卷 33-43页

作者： Peng Bai zheng ling Cong Liu Junshan Wu lingling Xie Marine Resources Big Data Center of South China Sea Southern Marine Science and Engineering Guangdong Laboratory(Zhanjiang)Zhanjiang 524025China Guangdong Province Key Laboratory for Coastal Ocean Variation and Disaster Prediction College of Ocean and MeteorologyGuangdong Ocean UniversityZhanjiang 524088China Ocean College Zhejiang UniversityZhoushan 316021China East China Sea Bureau of Ministry of Natural Resources Shanghai 200137China

Effects of currents on winter wind waves in the tide-dominated Qiongzhou Strait(QS)were numerically evaluated via employing the coupled ocean-atmosphere-wave-sediment transport(COAWST)modeling *** showed satisfactory model performance in simulating the intense tidal currents in the *** effects of sea level variations and tidal currents on waves were examined under the maximum eastward(METC)and westward(MWTC)tidal *** the east entrance area of the QS,the positive sea levels under the MWTC deepened the water depth felt by waves,benefiting the further propagation of wave energy into the inner strait and causing increased wave *** METC and the MWTC could both enhance the wave height in the east entrance area of the QS,mainly through current-induced convergence and wavenumber shift,*** current-induced refraction,the METC(MWTC)triggered counterclockwise(clockwise)rotation in peak wave directions in the northern part of the QS while clockwise(counterclockwise)rotation in the southern part.

关键词： Qiongzhou Strait COAWST significant wave height peak wave direction

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Preparation and properties of W–Cu–Zn alloy with low W–W contiguity

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Rare Metals 2016年第3期35卷 242-248页

作者： ling-ling zheng Jin-Xu Liu Shu-Kui Li Shuang Liu Qing-He Zou Xing-Wang Cheng School of Materials Science and Engineering Beijing Institute of Technology Mudanjiang North Alloy Tool Co. Ltd

The W–Cu–Zn alloy with a-brass matrix and low W–W contiguity was prepared by method of electroless copper plating combined with spark plasma sintering（SPS） *** effects of process and parameters on the microstructure and mechanical properties of the alloy were *** W–Cu–Zn alloy with a relative density of 96 % and a W–W contiguity of about 10 % was prepared by original fine tungsten particles combined with wet mixing method and SPS solid-state sintering method at 800℃ for 10 *** microstructure analysis shows that Cu–Zn matrix consists of nano-sized a-brass grains,and the main composition is Cu3Zn *** nano-sized Cu was coated on the surface of tungsten particles by electroless copper plating method,and the fairly low consolidation temperature and short solid-state sintering time result in the nano-sized matrix *** dynamic compressive strength of the W–Cu–Zn alloy achieves to1000 MPa,but the alloy shows poor ductility due to the formation of the hard and brittle Cu3Zn *** fine-grain strengthening and the solution strengthening of the Cu–Zn matrix phase are responsible for the high Vickers microhardness of about 300 MPa for W–Cu–Zn alloy.

关键词： W–Cu–Zn alloy Spark plasma sintering Microstructure Mechanical properties Microhardness

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The effect of cataract surgery on sleep quality:a systematic review and Meta-analysis

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International Journal of Ophthalmology(English edition) 2017年第11期10卷 1734-1741页

作者： ling zheng Xiao-Hang Wu Hao-Tian Lin State Key Laboratory of Ophthalmology Zhongshan Ophthalmic CenterSun Yat-sen UniversityGuangzhou 510060Guangdong ProvinceChina Jieyang People’s Hospital Jieyang Affiliated HospitalSun Yat-sen UniversityJieyang 522000Guangdong ProvinceChina

AIM： To evaluate the effect of cataract surgery on sleep quality and to compare the difference between ultravioletblocking clear intraocular lens（UVB-IOL） and blue-filtering intraocular lens（BF-IOL） ***： Electronic search was performed of PubM ed, MEDLINE, Embase and the Cochrane Library up to January 2016. Studies were eligible when they evaluated the sleep quality before and after cataract surgery by Pittsburgh sleep quality index（PSQI）. A random/fixed-effects Metaanalysis was used for the pooled estimate. Heterogeneity was assessed with the I2 test. RESULTS： Six studies were selected from 5623 references. Cataract surgery significantly reduced the PSQI scores at postoperative 0-3 mo [mean difference（MD） =-0.62, 95%CI：-1.14 to-0.11, P=0.02, I2=66%] and 3-12 mo（MD=-0.32, 95%CI：-0.62 to-0.02, P=0.04, I2=0）, respectively. Considering different intraocular lens（IOL） implantations, relative postoperative PSQI reduction was found for both UVB-IOL and BF-IOL, but a significant reduction was detected only for UVB-IOL. No significant difference was found with the effect of BF-IOL vs UVB-IOL on sleep quality. CONCLUSION： This study found that cataract surgery significantly improved the PSQI score-derived subjective sleep quality irrespective of the IOL type implanted. These findings highlight a substantial benefit of cataract surgery on systemic health with photoreceptive restoration in addition to visual acuity improvements.

关键词： cataract surgery intraocular lens implantation sleep quality

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