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Autonomous Vehicles Testing Considering Utility-Based Operable Tasks

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Tsinghua Science and Technology 2023年第5期28卷 965-975页

作者： Jingwei Ge Jiawei zhang Yi zhang Danya Yao zuo zhang Rui Zhou Department of Automation Tsinghua UniversityBeijing 100084China Department of Automation Beijing National Research Center for Information Science and Technology(BNRist)Tsinghua UniversityBeijing 100084Chinaand with Tsinghua-Berkeley Shenzhen Institute(TBSI)Shenzhen 518055Chinaand also with Jiangsu Province Collaborative Innovation Center of Modern Urban Traffic TechnologiesNanjing 210096China Macao University of Science and Technology Macao 999079Chinaand also with Waytous Inc.Shenzhen 518000China

Virtual simulation testing of Autonomous Vehicles(AVs)is gradually being accepted as a mandatory way to test the feasibility of driving strategies for *** methods focus on improving testing efficiency by extracting critical scenarios from naturalistic driving ***,the criticalities defined in their testing tasks are based on fixed assumptions,the obtained scenarios cannot pose a challenge to AVs with different *** fill this gap,we propose an intelligent testing method based on operable testing *** found that the driving behavior of Surrounding Vehicles(SVs)has a critical impact on AV,which can be used to adjust the testing task difficulty to find more challenging *** model different driving behaviors,we utilize behavioral utility functions with binary driving ***,we construct a vehicle interaction model,based on which we theoretically analyze the impact of changing the driving behaviors on the testing task ***,by adjusting SV’s strategies,we can generate more corner cases when testing different AVs in a finite number of simulations.

关键词： Autonomous Vehicle(AV) intelligence testing operable tasks

A GIS-based Spatial Analysis of Housing Price and Road Density in Proximity to Urban Lakes in Wuhan City, China

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Chinese Geographical Science 2015年第6期25卷 775-790页

作者： zhang zuo TAN Shukui TANG Wenwu College of Public Administration Huazhong University of Science and Technology School of Business Hubei University Department of Geography and Earth Sciences and Center for Applied GIScience University of North Carolina at Charlotte

As one of the essential urban open spaces, lakes usually contribute immensely to the quality of residents′ daily lives. Different from hedonic approach employed in existing researches on urban open spaces in China, this paper integrates housing price surface with road density to analyze the spatial characteristics in proximity to urban lakes in Wuhan City, China. With the expansion of Wuhan City, urban lakes became polluted, they shrunk or even disappeared, leading to unfavorable conditions for sustainable development of the city. To better understand the spatial relationship between the city and lakes, we classify the urban lakes in Wuhan central area into ′lakes in the urban center′ and ′lakes in urban fringe′. Based on housing price surface we explore the spatial characteristics in proximity to different lakes and differences between the lakes. We also use Geographic Information System(GIS) tool to calculate road density as a supplementary indicator to reflect the accessibility in proximity to urban lakes. The results indicate that relative independence exists between different towns, and the spatial characteristics are different depending on scales and locations. In most of cases, the road density is lower where closer to the lakeshore while the housing price exhibits an opposite pattern. We conclude that city governments and urban planners should give more considerations to these spatial differences, somewhere should be better planned and protected as an important waterfront and somewhere the control of unreasonable real estate development nearby should be strengthened.

关键词： urban lakes housing prices road density Geographic Information System (GIS) Wuhan City, China

The spring soil moisture and the summer rainfall in eastern China

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Chinese Science Bulletin 2007年第23期52卷 3310-3312页

作者： zuo ZhiYan zhang RenHe State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081 China

The relation between the soil moisture in spring and the rainfall in summer in eastern China is investi- gated. Results show that the summer rainfall in eastern China is closely related to the spring soil moisture in the area from North China to the lower reaches of Yangtze River (NCYR). When spring soil moisture anomalies over NCYR are positive, the summer precipitation exhibits positive anomalies in Northeast China and the lower reaches of Yangtze River, and negative anomalies in southern China and North China. The higher soil moisture over NCYR cools land surface and reduces the land-sea tem- perature gradient, which weakens East Asian summer monsoon. The western Pacific Subtropical High (WPSH) is located to the south and shifts westward, resulting in more rainfall in the lower reaches of Yangtze River and less in southern China and North China.

关键词：土壤湿度夏季中国气候

Helicobacter pylori infection and risk of gastric cancer in Changle County,Fujian Province,China

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World Journal of Gastroenterology 2000年第3期6卷 374-376页

作者： Lin Cai Shun zhang Yu zuo Feng zhang Department of Epidemiology Fujian Medical UniversityFuzhou 350004Fujian ProvinceChina Department of Epidemiology Shanghai Medical UniversityShanghai 200032China Department of Epidemiology UCLA School of Public HealthLos Angeles CaliforniaUSA

AIM To evaluate the effects of Helicobacterpylori infection and other environmental factorson the development of gastric *** A population-based case-controlstudy was conducted in Changle County,*** primary gastric cancer cases werehistologically confirmed or diagnosed by surgerybetween,January 1996 and March *** were randomly selected and matched byage,sex,and neighborhood of *** of 101 pairs were included in the *** trained interviewers conducted face-to-face interviews with the subjects according toa standardized *** infections were measured by serum IgGantibody to Helicobacter *** Regression analysis was *** The presence of IgG antibody toHelicobacter pylori was 63.7% in studysubjects,56.0% in patients with cardiac cancer,and 60.5% in patients with non-cardiac *** risk factors of gastric cancer inChangle County were identified such as loweducational level[OR=3.864;95% confidenceinterval(95% CI)1.604-9.311],lowconsumption of fresh vegetables(OR=4.925;95%Cl 1.356-17.885),high intake of fish sauce(OR=10.587;95% Cl 2.821-39.738),unscheduled meals(OR=4.254;95%Cl 1.445- 12.552),and Helicobacter pylori infection(OR=3.453;95%Cl 0.901-13.224).CONCLUSION Helicobacter pylori infectionmay be important in the etiology of gastriccancer,but major risk factors other thanHelicobacter pylori are responsible for the highgastric morbidity in Changle County.

关键词： Helicobacter pylori stomach neoplasm risk factors case control studies

Crystallization Behavior in Fluoride-Free Mold Fluxes Containing TiO_2/ZrO_2

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Journal of Iron and Steel Research International 2011年第5期18卷 31-37页

作者： zhang zuo-tai LI Jing LIU Peng College of Engineering Peking UniversityBeijing 100871China

The time-temperature-transformation （TTT） diagrams of fluoride-free mold fluxes containing TiO2/ZrO2 were constructed through the confocal scanning laser microscope （CSLM） technique. It was found that the crystallization temperature of F-free mold fluxes containing TiO2 or ZrO2 increases,while incubation time decreases with increasing basicity. The crystallization tendency increases with the zirconia addition in slag melt,as it may be thought that the addition solubility is limited in molten slag and the solid particles act as heterogeneous nucleation sites. Three types of crystal morphologies were observed,corresponding to different crystallization mechanisms. CaSiO3 and Ca3Si2O7 precipitate in the slag with low basicity,and Ca2SiO4 was formed with increasing basicity. The addition of TiO2 promotes the precipitation of CaTiO3. The logarithm of crystal growth rate increased with increasing isothermal temperature,suggesting that the crystal/melt interface reaction is the controlling step in the present experiment.

关键词： crystallization fluoride-free mold flux TTT diagram ZrO2 TiO2

Development *** in limited urban sprawl:An integrated framework for resolving the urban boundary dilemma in China

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Journal of Geographical Sciences 2024年第7期34卷 1371-1393页

作者： SONG Xiangxiang zhang zuo WANG Zhe LIU Yanzhong School of Public Administration Central China Normal UniversityWuhan430079China College of Resource and Environmental Engineering Wuhan University of Science and TechnologyWuhan430081China

The strategic delineation of the urban development boundary(UDB)is an effective initiative for efficient land resource allocation and for facilitating planned urban *** align with sustainable development objectives,UDB definitions have evolved to reconcile urban development with ecological *** study presents a UDB delineation framework from an integrated perspective that incorporates both demand-oriented and comprehensive ***,the urban construction land demand area was estimated based on population projections,meanwhile,the ecological red line(ERL)was delineated and integrated into the evaluation of the construction land ***,with the demand area as the simulation target and unsuitable areas as comprehensive constraints,the UDB was delineated by simulating future land use *** proposed framework was applied to Wuhan,a rapidly urbanizing city in central China,where the delineation of the UDB serves the dual purpose of managing the rapid expansion of built-up land and achieving a harmonious balance between urban development imperatives and ecological protection ***,based on the results and analysis,policy implications for the rational spatial planning of Wuhan were proposed,encompassing the spatial patterns and scientific decision-making in ecological conservation and urban *** results demonstrate that the efficacy of adopting a comprehensive perspective in delineating UDB effectively reconciles the competing needs of urban development and *** framework and the policy insights derived in this study could inform spatial planning efforts not only in Wuhan but also in other cities facing the dilemma of urban development and ecological protection.

关键词： urban development boundary(UDB) ecological red line(ERL) urban land suitability land use simulation integrated framework spatial decision-making

Effect of Alloying Elements(Sb,B) on Recrystallization and Oxidation of Mn-Containing IF Steel

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Journal of Iron and Steel Research International 2013年第3期20卷 39-44,56页

作者： zhang Ya-long zhang Ying-yi YANG Fei-hua zhang zuo-tai Department of Energy and Resources Engineering College of EngineeringPeking University Beijing Building Materials Academy of Sciences Research

The effects of minor alloying elements（antimony,boron） on the recrystallization and oxidation of Mn-containing interstitial free（IF） steels were investigated using confocal scanning laser microscope（CSLM） under controlled atmosphere of 95% Ar and 5% H2（volume percent） at different *** results indicated that oxidation and recrystallization were primarily controlled by the grain boundaries,which moved due to release of the stored energy or acted as the fast path diffusion of alloying *** was found that the addition of antimony suppressed both surface oxidation and internal oxidation,whereas boron addition accelerated surface oxidation but decreased internal *** reasons caused were that the alloying elements of antimony or boron were known to segregate on the surfaces or grain boundaries to occupy the surface adsorption sites,which were expected to be less catalytic than bare iron on the transportation of alloying *** recrystallization was also retarded through adding minor antimony and boron *** oxidation kinetics of formation of grain boundary oxides were studied through calculating the areas along grain boundaries,and it was found that the areas parabolically increased with increasing time.

关键词： IF steel boron antimony oxidation recrystallization

Dangerous Driving Behavior Recognition and Prevention Using an Autoregressive Time-Series Model

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Tsinghua Science and Technology 2017年第6期22卷 682-690页

作者： Hongxin Chen Shuo Feng Xin Pei zuo zhang Danya Yao Department of Automation Tsinghua UniversityBeijing 100084China

Time headway is an important index used in characterizing dangerous driving behaviors. This research focuses on the decreasing tendency of time headway and investigates its association with crash occurrence. An autoregressive（AR） time-series model is improved and adopted to describe the dynamic variations of average daily time headway. Based on the model, a simple approach for dangerous driving behavior recognition is proposed with the aim of significantly decreasing headway. The effectivity of the proposed approach is validated by means of empirical data collected from a medium-sized city in northern China. Finally, a practical early-warning strategy focused on both the remaining life and low headway is proposed to remind drivers to pay attention to their driving behaviors and the possible occurrence of crash-related risks.

关键词： time headway driving behavior traffic safety autoregressive time-series model remaining life driving warning strategy

A Robust Discontinuous Galerkin Method for Solving Convection-diffusion Problems

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Acta Mathematicae Applicatae Sinica 2008年第3期24卷 483-496页

作者： zuo-zheng zhang Zi-qing Xie Xia Tao College of Mathematics and Computer Science Hunan Normal University Changsha 410081 China

In this paper, a new DG method was designed to solve the model problem of the one-dimensional singularly-perturbed convection-diffusion equation. With some special chosen numerical traces, the existence and uniqueness of the DG solution is provided. The superconvergent points inside each element are observed. Particularly, the 2p ＋ 1-order superconvergence and even uniform superconvergence under layer-adapted mesh are observed numerically.

关键词： Discontinuous Galerkin method singularly perturbed convection-diffusion numerical traces