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Model calibration concerning risk coefficients of driving safety field model 被引量:5
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作者 LI Yang WANG Jian-qiang WU Jian 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第6期1494-1502,共9页
Driving safety field(DSF) model has been proposed to represent comprehensive driving risk formed by interactions of driver-vehicle-road in mixed traffic environment. In this work, we establish an optimization model ba... Driving safety field(DSF) model has been proposed to represent comprehensive driving risk formed by interactions of driver-vehicle-road in mixed traffic environment. In this work, we establish an optimization model based on grey relation degree analysis to calibrate risk coefficients of DSF model. To solve the optimum solution, a genetic algorithm is employed. Finally, the DSF model is verified through a real-world driving experiment. Results show that the DSF model is consistent with driver's hazard perception and more sensitive than TTC. Moreover, the proposed DSF model offers a novel way for criticality assessment and decision-making of advanced driver assistance systems and intelligent connected vehicles. 展开更多
关键词 intelligent CONNECTED vehicles advanced DRIVER ASSISTANCE systems (ADAS) driving risk assessment driving safety field (DSF) model parameter calibration GREY RELATION degree
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The stress field variation caused by faulting and the prediction for seismic risk 被引量:1
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作者 赵根模 姚兰予 马淑芹 《Acta Seismologica Sinica(English Edition)》 CSCD 1994年第4期559-566,共8页
The stress field caused by faulting has an effect on the stability of the neighboring faults, and the study on the fault interaction has a close relation with the prediction of seismic risk. Stress field caused by the... The stress field caused by faulting has an effect on the stability of the neighboring faults, and the study on the fault interaction has a close relation with the prediction of seismic risk. Stress field caused by the rectangle fault in the semi-infinite elastic medium is calculated on the basis of the elastic dislocation theory. The result shows that most of the successive large earthquakes, in the southwestern part of China and North China, occurred in the increasing area of shear stress S(xy) and the decreasing area of normal stress S(yy) The increasing of earthquake occurrence probability has a function relation with the increasing of stress. Earthquake triggering is resulted from the increasing of shear stress and the decreasing of normal stress. An activation coefficient A, of the earthquake is defined to express the change of seismic activity. The concrete risk region can be obtained through space scanning of At value. Finally, the fault interaction in a large scope is discussed in this paper. 展开更多
关键词 fault interaction variation of stress field earthquake triggering seismic risk
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Modeling the fate of paddy field pesticide in surface water and environmental risk assessment
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作者 LI Shi\|yu 1, Tohru Morioka 2 (1. Institute of Environmental Science, Zhongshan University, Guangzhou 510275, China. E-mail: eeslsy@zsu.edu.cn 2.Department of Environmental Engineering, Osaka University, Yamada oka 2 1, Suita, Osaka 565, Japan. E- 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2000年第3期337-343,共7页
The risk of drinking water is greatly concerned because of the large amount of pesticide applied to paddy field and the contamination of drinking water sources due to the runoff. A mathematical model is developed, ba... The risk of drinking water is greatly concerned because of the large amount of pesticide applied to paddy field and the contamination of drinking water sources due to the runoff. A mathematical model is developed, based on the mass balance, to predict the fate of paddy field pesticides from application, runoff and mixing in a river, taking account of the physical chemical properties and processes of volatilization, degradation, adsorption and desorption. The model is applied to a river basin in Japan to estimate the contaminant level of several popularly used pesticides at the water intakes. The health risk in drinking water induced by each pesticide concerned is estimated and evaluated by comparing with the acceptable daily intake values(ADI) and with that induced by trihalomethanes. An index to evaluate the total risk of all pesticides appearing in water is proposed. The methods for risk management are also discussed. 展开更多
关键词 MODELING PESTICIDE paddy field environmental risk assessment drinking water
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Synoptic Analysis Clarifies Childhood Leukemia Risk from ELF Magnetic Field Exposure
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作者 Norbert Leitgeb 《Journal of Electromagnetic Analysis and Applications》 2015年第10期245-258,共14页
In spite of 36 years epidemiologic research, there is still an ongoing controversy about a causal link between childhood leukemia (CL) and exposure to extremely low frequency (ELF) magnetic fields (MF). Public concern... In spite of 36 years epidemiologic research, there is still an ongoing controversy about a causal link between childhood leukemia (CL) and exposure to extremely low frequency (ELF) magnetic fields (MF). Public concern has been increased by the fact that ELF MF have been classified as possibly carcinogenic to humans (class 2B) while exposure limits still remain three orders of magnitudes above reported CL risk onset levels. In a new synoptic approach rather than few selected ORs, all reported epidemiological risk estimates (ORs) are analyzed, both pooled together as well as separated into sub-pools of different exposure metric as well as of high and low exposure levels. The results explain the worrying offset of ORs towards increased CL risk as well as the reported puzzling dose-response at low MF levels as an artifact caused by the small-number effect. The synoptic analysis clarifies that ORs critically depend on statistical power. With increasing statistical power ORs decrease and finally converge to and stay at zero risk. This is found consistently at the entire data pool as well as at all sub-pools related to investigated exposure parameters (wire code, distance to MF source, and magnetic field value). Former contradictory results can now be explained. The synoptic analysis provides convincing evidence that the risk of childhood leukemia is not increased by exposure to ELF magnetic fields. IARC’s classification of ELF MF needs revision. 展开更多
关键词 HEALTH risk LONG-TERM Effect CARCINOGENICITY Magnetic field Power LINE
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Research on Safety Risk Assessment Method for Large Scale Field Operation Project
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作者 JIANG Wei-yang ZHAO Man-yun +1 位作者 ZHANG Lian SONG Wei-dong 《International Journal of Plant Engineering and Management》 2016年第2期65-74,共10页
By applying man-machine-environment system engineering theory, safety risks on large scale field operation project have been evaluated in this article. The factors concerning with the man, machine and environment in s... By applying man-machine-environment system engineering theory, safety risks on large scale field operation project have been evaluated in this article. The factors concerning with the man, machine and environment in system were proposed separately. The value for lowest indexs was determined by decision-making of expert group. The weights were calculated based on AHP, and then safety risk assessment in different layers was made. The results show that the assessment method is reasonable, and it is significant for large scale field operation project safety managerment. 展开更多
关键词 large scale field operation project safety risk assessment man-machine-environment system
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银行货币储备博弈的强化学习方法
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作者 李策 《数学杂志》 2025年第1期81-94,共14页
在大规模银行交互系统中,各银行可通过控制与中央银行的借贷率来使自身对数货币储备尽可能地接近样本均值,从而降低系统性风险发生的概率.然而当状态过程与目标函数的参数未知时,无法直接求解随机微分博弈问题得到纳什均衡.本文结合平... 在大规模银行交互系统中,各银行可通过控制与中央银行的借贷率来使自身对数货币储备尽可能地接近样本均值,从而降低系统性风险发生的概率.然而当状态过程与目标函数的参数未知时,无法直接求解随机微分博弈问题得到纳什均衡.本文结合平均场博弈理论与连续时间强化学习的相关方法,构造了一组大规模银行借贷网络中的近似纳什均衡.首先通过求解向前向后耦合HJB-FPK方程,得到代表银行的平均场均衡策略;再通过所得策略的形式,设计出迭代参数的方法用以刻画参数未知时的近似最优策略;最后通过学到的参数,构造银行数量较大时的近似纳什均衡. 展开更多
关键词 系统性风险 强化学习 近似纳什均衡 平均场博奔
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Assessing field vulnerability to phosphorus loss in Beijing agricultural area using Revised Field Phosphorus Ranking Scheme 被引量:7
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作者 LI Qi CHEN Li-ding +3 位作者 QI Xin ZHANG Xin-yu MA Yan FU Bo-jie 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第8期977-985,共9页
Guanting Reservoir, one of the drinking water supply sources of Beijing, suffers from water eutrophication. It is mainly supplied by Guishui River. Thus, to investigate the reasons of phosphorus (P) loss and improve... Guanting Reservoir, one of the drinking water supply sources of Beijing, suffers from water eutrophication. It is mainly supplied by Guishui River. Thus, to investigate the reasons of phosphorus (P) loss and improve the P management strategies in Guishui River watershed are important for the safety of drinking water in this region. In this study, a Revised Field P Ranking Scheme (PRS) was developed to reflect the field vulnerability of P loss at the field scale based on the Field PRS. In this new scheme, six factors are included, and each one was assigned a relative weight and a determination method. The affecting factors were classified into transport factors and source factors, and, the standards of environmental quality on surface water and soil erosion classification and degradation of the China were used in this scheme. By the new scheme, thirty-four fields in the Guishui River were categorized as "low", "medium" or "high" potential for P loss into the runoff. The results showed that the P loss risks of orchard and vegetable fields were higher than that of corn and soybean fields. The source factors were the main factors to affect P loss from the study area. In the study area, controlling P input and improving P usage efficiency are critical to decrease P loss. Based on the results, it was suggested that more attention should be paid on the fields of vegetable and orchard since they have extremely high usage rate of P and high soil test of P. Compared with P surplus by field measurements, the Revised Field PRS was more suitable for reflecting the characteristics of fields, and had higher potential capacity to identify critical source areas of P loss than PRS. 展开更多
关键词 phosphorus loss risk assessment field scale revised phosphorus ranking scheme management strategy
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Analysis and study of the large earthquake risk in Yanqing-Huailai basin 被引量:1
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作者 刘昌铨 嘉世旭 +1 位作者 刘明军 李长发 《Acta Seismologica Sinica(English Edition)》 CSCD 1997年第5期84-92,共9页
On the basis of study results of deep sounding in the Yanqing Huailai basin, the shallow active tectonics, palaeoseismic events, seismic activity, distribution of crustal stress field and other related data are combi... On the basis of study results of deep sounding in the Yanqing Huailai basin, the shallow active tectonics, palaeoseismic events, seismic activity, distribution of crustal stress field and other related data are combined to study the earthquake risk of the basin comprehensively. Meanwhile, the comparison of deep structures between the basin and some other earthquake regions such as the Xingtai area is made. It is thought that there is the background of deep structures for occurrence of moderate and strong earthquakes in the Yanqing Huailai basin and its periphery, and the possibility for an M =7 earthquake to occur there cannot be excluded. 展开更多
关键词 deep sounding stress field strong earthquake risk
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Ecological Risk Assessment of Shan Xin Mining Area Based on Remote Sensing and Geography Information System Technology 被引量:2
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作者 Chaokui Li Jianhui Chen +2 位作者 Mengguang Liao Guo Chen Qinlan Zhou 《Journal of Geographic Information System》 2018年第2期234-246,共13页
In this paper, introducing new remote sensing and geographic information technology to solve the problem of data collection and analysis, this makes the study of ecological risk assessment very quick and accurate. Tak... In this paper, introducing new remote sensing and geographic information technology to solve the problem of data collection and analysis, this makes the study of ecological risk assessment very quick and accurate. Taking the Shan Xin mining area of the tin mine in Lengshuijiang of Hunan Province as the research object, using the remote sensing image data of three periods in 2005, 2010 and 2015, the remote sensing image is classified carefully and the landscape classification map of the mining area is obtained. The ecological risk index is introduced and the ecological risk values are sampled and interpolated on the ArcGIS platform. The ecological risk spatial distribution map based on the landscape pattern index was obtained. The ecological risk was divided into 5 levels by using the Jenks natural classification method, and each ecological risk grade area was counted. The research results show that: from year 2005 to year 2010, landscape ecological risk trend of the mining area is growing up;the trend rising area of landscape ecological risk is mainly in the southwest and northeast of the Shan Xin mining field;the area of higher and high ecological risk is increasing year by year;and the trend of dispersed development in space is obvious;the development trend of ecological risk in the mining area is rapidly increasing;in 2010 - 2015, the higher and high ecological risk area decrease slightly with the increasing of area of grassland and residential low vulnerability of landscape types;the ecological risk area showed a slow decreasing trend. The research results provide an objective reference for decision making of ecological environment governance. 展开更多
关键词 RS & GIS TECHNOLOGY Shan Xin MINING field ECOLOGICAL risk Assessment Jenks NATURE Classification risk Index
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Influence of Distinct Radiotherapy Techniques to Induce Second Cancer Risks in Left Breast Cancer
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作者 Raghda A. Elgendy Wahib M. Attia +1 位作者 Ehab M. Attalla Mostafa A. Elnaggar 《International Journal of Medical Physics, Clinical Engineering and Radiation Oncology》 2018年第2期193-202,共10页
Influence of distinct radiotherapy techniques to induce second cancer risks in left breast cancer. Material and methods: Ten female patients with intact left breast cancer. Two treatment plans for each patient: 1) two... Influence of distinct radiotherapy techniques to induce second cancer risks in left breast cancer. Material and methods: Ten female patients with intact left breast cancer. Two treatment plans for each patient: 1) two tangential beams 3D-Conformal radiotherapy, 2) intensity-modulated radiotherapy (IMRT) plan. Estimation of second cancer risk from Organ equivalent dose models (OEDs) in three dose-response model for organs at risk in left breast cases. Results: The P-value for OED models in 3D-IMRT for left lung, both lung, heart, right lung, right breast, thyroid, liver and spinal cord in linear dose model was 0.016, 0.005, 0.019, 3.95E-06, 5.79E-07, 0.003, 1.78E-10 and 0.000206475 respectively, for linear exponential dose model 0.0577, 0.024, 0.031, 3.40E-06, 3.28E-07, 0.003, 2.01E-10 and 0.000120072 respectively and in plateau dose model 0.088, 0.042, 0.039, 3.18E-06, 2.53E-07, 0.003, 2.27E-10 and 9.00535E-05 respectively. Conclusion: organ equivalent dose models for organs at risk increasing in IMRT than tangential beams. 展开更多
关键词 Breast CANCER Second CANCER riskS 3DCRT 7 field IMRT
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Synoptic Analysis of Epidemiologic Evidence of Brain Cancer Risks from Mobile Communication 被引量:1
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作者 Norbert Leitgeb 《Journal of Electromagnetic Analysis and Applications》 2014年第14期413-424,共12页
In the radio frequency (RF) range concern about long-term health risks from electromagnetic fields (EMF) is enhanced by contradictory results and conclusions from epidemiologic studies. A new approach of a synoptic an... In the radio frequency (RF) range concern about long-term health risks from electromagnetic fields (EMF) is enhanced by contradictory results and conclusions from epidemiologic studies. A new approach of a synoptic analysis of all available data from epidemiological studies published since 2001 was performed. This approach provided new insight with regard to a potential link between mobile phone use and brain cancer. Two quite different data pools could be identified with numerous studies from one research group opposing all other studies. However, it could be shown that with the number of exposed cases both data pools exhibit a clear trend of risk estimates (odds ratios) towards the final result, namely a reduced cancer risk of OR = 0.8, though from either side of the zero-risk line. The analysis of potential long-term effects indicated by a dosedependence revealed diverging results with different dose metrics. Overall, the synoptic analysis supports reassuring rather than alarming conclusions on RF EMF health risks from mobile telecommunication. 展开更多
关键词 Health risk LONG-TERM Effect CARCINOGENICITY ELECTROMAGNETIC field Mobile PHONE
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计及安全性与舒适性的智能车辆换道轨迹规划研究
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作者 陈峥 赵文龙 +3 位作者 郭凤香 赵志刚 刘昱 刘永刚 《交通运输系统工程与信息》 EI CSCD 北大核心 2024年第1期55-65,共11页
针对当前智能车辆在换道过程中的安全性以及乘员舒适性问题,本文提出一种基于风险场评估轨迹的二次筛选方法。首先,在Frenet坐标系下,将车辆运动解耦为横向和纵向两个维度,基于五次多项式生成所有横向d-t曲线簇和纵向s-t曲线簇;其次,由... 针对当前智能车辆在换道过程中的安全性以及乘员舒适性问题,本文提出一种基于风险场评估轨迹的二次筛选方法。首先,在Frenet坐标系下,将车辆运动解耦为横向和纵向两个维度,基于五次多项式生成所有横向d-t曲线簇和纵向s-t曲线簇;其次,由车辆的动力学特性和三圆碰撞模型设计轨迹初筛评价函数,选取合格轨迹作为候选轨迹;最后,参考人工势场理论的思想,引入行车过程中风险场的概念,根据换道效率,换道风险值和横、纵向冲击度建立总损失函数评价候选轨迹以进行二次筛选,选取最佳轨迹并完成可视化。为检验算法的可行性,通过搭建双车道的道路环境,设计障碍车不同速度和加速度的多场景进行弯道换道的仿真验证。研究结果表明,本文所提算法能够满足换道的安全性和舒适性需求。同时,在正常换道场景下,乘员在换道过程的97.5%时间处于舒适状态,在紧急避障场景下也能达到平衡安全性与舒适性的目标。 展开更多
关键词 智能交通 换道轨迹规划 风险场 智能车辆 Frenet坐标系 乘员舒适性
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基于驾驶风格的山区公路穿村镇段行车风险场灵敏度分析
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作者 戢晓峰 王健 +2 位作者 徐迎豪 卢梦媛 覃文文 《交通运输系统工程与信息》 EI CSCD 北大核心 2024年第6期316-325,共10页
针对山区公路穿村镇段交通事故多发的现实问题,本文提出一种考虑驾驶风格的行车风险识别方法,通过灵敏度分析揭示驾驶风格在风险评估中的影响,并以云南省典型山区公路穿村镇段为实例进行验证。首先,利用无人机采集车辆轨迹数据,建立轨... 针对山区公路穿村镇段交通事故多发的现实问题,本文提出一种考虑驾驶风格的行车风险识别方法,通过灵敏度分析揭示驾驶风格在风险评估中的影响,并以云南省典型山区公路穿村镇段为实例进行验证。首先,利用无人机采集车辆轨迹数据,建立轨迹分析数据库;其次,基于行车风险场理论并通过事故数据的相关性分析,刻画穿村镇段行车环境对车辆行驶的风险影响,进一步引入驾驶风格因子,建立考虑驾驶风格的行车风险场,实现多要素的综合考虑与行车风险量化;最后,基于Sobol全局灵敏度分析方法,分析考虑驾驶风格前后模型关键参数的全局灵敏度,并实现区域风险的可视化。研究结果表明:当选择速度均值、加速度均值和冲击度方差进行驾驶风格划分,K值为4时聚类效果最佳;Sobol法有效评估了参数灵敏度,当考虑驾驶人行为场后,总灵敏度分布更加均匀,模型考虑因素更为广泛,其中速度和冲击度标准差为最显著参数,总灵敏度分别为0.41和0.34;对多车共同作用产生的风险可视化显示,势场范围随道路线形变化而变化,在穿村镇交叉口风险值最显著,整体行驶速度降比为17.39%,将进一步发挥风险场理论在微观交通风险评估中的作用。 展开更多
关键词 交通工程 风险场模型 灵敏度分析 穿村镇道路 驾驶风格 山区公路
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面向车载相机采集图像的智能汽车测试场景关键性量化模型
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作者 朱冰 黄殷梓 +2 位作者 赵健 张培兴 薛经纬 《汽车工程》 EI CSCD 北大核心 2024年第4期557-563,576,共8页
车载相机图像是构建智能汽车测试场景库的主要数据来源,但其中关键测试场景发生概率低,大部分场景的测试价值小,若将其直接应用于智能汽车测试会浪费大量测试资源。本文提出一种面向车载相机采集图像的智能汽车测试场景关键性量化模型... 车载相机图像是构建智能汽车测试场景库的主要数据来源,但其中关键测试场景发生概率低,大部分场景的测试价值小,若将其直接应用于智能汽车测试会浪费大量测试资源。本文提出一种面向车载相机采集图像的智能汽车测试场景关键性量化模型。首先,基于实车相机参数对实车采集的图像进行处理,输出对行车安全具有影响的参数;其次,基于风险场理论将参数整合,输出测试场景关键性量化结果;最后,对实车采集的图像进行测试场景关键性量化验证,结果表明本文模型可以精确输出测试场景关键性的具体数值,进而对比不同场景的测试价值,证明本文提出的模型可以有效筛选智能汽车关键测试场景。 展开更多
关键词 智能汽车 测试场景 关键性量化模型 车载相机图像 风险场理论
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Synoptic Analysis of Epidemiologic Evidence of Glioma Risk from Mobile Phones
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作者 Norbert Leitgeb 《Journal of Electromagnetic Analysis and Applications》 2015年第9期233-243,共11页
Concern about brain cancer risks from mobile phone use, in particular of glioma, is mainly based on epidemiologic studies reporting on an increased risk estimate (odds ratio, OR) in particular of long-term and/or heav... Concern about brain cancer risks from mobile phone use, in particular of glioma, is mainly based on epidemiologic studies reporting on an increased risk estimate (odds ratio, OR) in particular of long-term and/or heavy users. Concern is enhanced by contradictory results and alarming conclusions from some epidemiologic studies. In a new synoptic approach all reported data from epidemiological studies published since 2001 were analyzed. This approach provided new insight with regard to the suspected link between mobile phone use and glioma. Two quite different data pools could be identified with numerous studies from one single research group opposing all other national and international studies. It could be shown that in spite of puzzling differences of their data pattern, in dependence of the number of exposed cases both data pools exhibit the similar trend of ORs towards reduced glioma risk with increasing statistical power, finally even converging towards a reduced risk, although from either side of the zero-risk line. While in the pooled data a potential long-term risk could be masked by reassuring short-term data the synoptic analysis in dependence of dose surrogates such as cumulated use time, cumulated call time or cumulated number of calls the seemingly increased long-term risk of glioma could be identified as an effect from low statistical power. In spite of worrying differences among some epidemiological studies, overall, the synoptic analysis of the entire body of data supports reassuring rather than alarming conclusions on glioma risks from mobile phone use even in long-term and/or heavy users. 展开更多
关键词 Health risk DOSE Response CARCINOGENICITY Electromagnetic field TELECOMMUNICATION
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高速公路隧道出口区域交通风险场识别研究
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作者 胡立伟 胡飞宇 +3 位作者 赵雪亭 杨志莹 王兴中 余先林 《安全与环境学报》 CAS CSCD 北大核心 2024年第1期53-62,共10页
为分析车辆在高速公路隧道出口区域的行驶安全规律,定量识别风险水平,参考相关领域的场论研究,结合交通特征要素,提出交通风险场理论,从人-车-环境多角度考虑高速公路隧道出口区域的风险特征。首先通过驾驶员瞳孔变化差异,将隧道出口区... 为分析车辆在高速公路隧道出口区域的行驶安全规律,定量识别风险水平,参考相关领域的场论研究,结合交通特征要素,提出交通风险场理论,从人-车-环境多角度考虑高速公路隧道出口区域的风险特征。首先通过驾驶员瞳孔变化差异,将隧道出口区域划分为隧道出口接近段、隧道出口段和隧道出口过渡段。其次参考环境风险场及场论等相关理论,将交通风险场根据不同因素的作用方式细化为点效应场、线效应场及面效应场,建立综合风险效应场模型。最后通过实地调查,获取云南省不同高速公路隧道出口区域的人、车、环境等相关交通信息数据,代入模型后得到高速公路隧道出口区域风险场。通过得到的交通风险场特征对照速度协调评价法得出的风险分布规律,验证交通风险场模型的可行性。结果表明:隧道出口接近段驾驶风险场强较大但影响范围小;隧道出口段的风险场强呈现先窄后宽的变化特征;出口过渡段前100 m路段风险水平最高,过渡段后100 m路段车速逐渐平稳,风险水平较低。通过交通风险场理论的应用可知,交通风险场强模型可以有效评估不同道路环境下交通风险分布,且较传统风险识别方式更加具有时空特征,可以准确地找到交通环境中的风险强点,针对性地进行调整,为今后的道路风险防控奠定基础。 展开更多
关键词 安全工程 交通安全 风险场模型 交通风险场 风险识别
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基于行车风险场的快速路短交织区车辆交互风险识别
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作者 胡立伟 陈琛 +4 位作者 赵雪亭 刘冰 侯智 张瑞杰 贺雨 《交通运输系统工程与信息》 EI CSCD 北大核心 2024年第3期221-231,共11页
为更加准确和直观地识别快速路短交织区行驶车辆之间的交互风险,解决传统风险识别模型无法连续识别换道时车辆间交互风险的问题,本文利用无人机采集快速路短交织区内车辆轨迹数据,并利用Tracker进行读取,筛选跟驰车辆对和换道车辆对,在... 为更加准确和直观地识别快速路短交织区行驶车辆之间的交互风险,解决传统风险识别模型无法连续识别换道时车辆间交互风险的问题,本文利用无人机采集快速路短交织区内车辆轨迹数据,并利用Tracker进行读取,筛选跟驰车辆对和换道车辆对,在现有行车风险场理论的基础上,综合考虑车辆面积、车辆前进时前后方风险差异、转弯时左右方风险差异以及车辆之间横向距离,适应性改进现有行车风险场模型DRF(Driving Safety Field),利用遗传算法和波良可夫模型标定模型参数。对比改进后行车风险场模型、车头时距倒数(THWI)、碰撞时间倒数(TTCI)对车辆间跟驰交互风险与换道交互风险的识别情况,验证该模型的有效性。结果表明,本文模型较THWI和TTCI更符合驾驶员的驾驶心理,且感知风险变化先于驾驶员,对车辆换道交互风险的识别率较THWI提升52.45%,较TTCI提升83.66%,本模型在换道交互风险的识别性能上表现的更加优越。基于本文模型对短交织区区域内多车共同作用产生的风险进行可视化,可辅助交通管理部门确定需要精细化组织的关键区域,也可作为评价管理措施改善效果的可视化手段。 展开更多
关键词 交通工程 交互风险识别 行车风险场 短交织区 风险可视化
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Evaluation of Heavy Metal Pollution in Dazhai Mellow-soil Field 被引量:1
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作者 Jingjing ZHANG Yongqing ZHANG +1 位作者 Hua ZHANG Wenjuan ZHANG 《Asian Agricultural Research》 2016年第1期40-43,共4页
In order to determine the pollution condition of heavy metal in Dazhai mellow-soil field,the content of Zn,Cr,Cu,Ni,Pb,As,Cd and Hg in this area were analyzed,the content of heavy metals in soils in Shanxi Soil Enviro... In order to determine the pollution condition of heavy metal in Dazhai mellow-soil field,the content of Zn,Cr,Cu,Ni,Pb,As,Cd and Hg in this area were analyzed,the content of heavy metals in soils in Shanxi Soil Environment Quality Standard and the secondary standard of National Soil Environment Quality Standard were used as evaluation standard. Based on the single factor index method,the result showed that the content of 8 heavy metals in soil didn't exceed the secondary standard of National Soil Environment Quality Standard,while the content of As,Hg,Ni,Pb exceeded Shanxi Soil Environment Quality Standard. The soil in the study areas reached high pollution of As,Hg,Pb,and the pollution index of Cu,Ni,Zn,Cd reached a high level. The potential ecological risk index order was Hg ﹥ Cd ﹥ As ﹥ Pb ﹥ Ni﹥ Cu ﹥ Zn ﹥ Cr. The pollution level risk intensity was mild. The correlation analysis indicated that Cr,Ni,Zn,Cu,Cd and As were probably from the same source,while Hg and other heavy metals were not correlated. Heavy metals with high levels of pollution were closely related to agricultural fertilization,tourism,transportation,construction,daily life and production activities. 展开更多
关键词 Dazhai mellow-soil field SOIL HEAVY metal POLLUTION ECOLOGICAL risk
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基于风险场的不同认知次任务下接管风险评估模型
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作者 马艳丽 秦钦 +1 位作者 董方琦 娄艺苧 《汽车工程》 EI CSCD 北大核心 2024年第1期9-17,28,共10页
为有效评估不同认知次任务下L3级自动驾驶车辆接管时的风险,开展了驾驶接管风险评估模型研究。设计了城市快速路紧急接管场景并开展不同认知次任务下的驾驶模拟试验。考虑轨迹场、势能场和行为场因素,构建了接管风险评估模型。采用接管... 为有效评估不同认知次任务下L3级自动驾驶车辆接管时的风险,开展了驾驶接管风险评估模型研究。设计了城市快速路紧急接管场景并开展不同认知次任务下的驾驶模拟试验。考虑轨迹场、势能场和行为场因素,构建了接管风险评估模型。采用接管风险指数法,验证了所建模型的有效性。结合实测数据,量化不同认知次任务和回避操作类型对接管风险场场强的影响。结果表明:被试者进行接管操作后1~9 s内模型接管风险指数分布情况的M-W检验和K-S检验结果均为p<0.05,说明模型可以有效评估车辆在接管过程中的接管风险。此外,模型接管风险指数的均方根误差均值(0.062)小于碰撞时间倒数的均方根误差均值(0.098),说明模型在表征风险的准确性方面要优于碰撞时间倒数。研究结果可为接管过程中的车辆运行风险评估和避撞设计提供借鉴和参考。 展开更多
关键词 交通工程 自动驾驶 风险评估模型 行车风险场 驾驶接管
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基于行车风险场的自动驾驶接管风险评估模型
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作者 马艳丽 董方琦 +1 位作者 秦钦 郭蓥蓥 《哈尔滨工业大学学报》 EI CAS CSCD 北大核心 2024年第9期106-112,共7页
为评估L3级自动驾驶的接管风险,降低接管过程中的事故率,设计城市快速路接管场景并开展驾驶模拟实验,以行车风险场理论为基础,采用动态和静态风险分布函数反映其他交通单元对接管风险的影响,引入车辆性能概率因子对自动驾驶接管过程中... 为评估L3级自动驾驶的接管风险,降低接管过程中的事故率,设计城市快速路接管场景并开展驾驶模拟实验,以行车风险场理论为基础,采用动态和静态风险分布函数反映其他交通单元对接管风险的影响,引入车辆性能概率因子对自动驾驶接管过程中的事故发生概率进行表征,同时考虑接管反应时间的影响,构建自动驾驶接管风险评估模型,基于驾驶模拟实验获取接管反应时间数据和车辆轨迹数据对模型参数进行标定,并与碰撞时间倒数进行对比,验证模型的有效性。结果表明:驾驶员接管后1~9 s内模型计算所得的接管风险指数的变化趋势与碰撞时间倒数一致,但接管过程中风险指数的均方根误差均值(0.059)相较于碰撞时间倒数的均方根误差均值(0.093)下降了37%。构建的模型能够有效评估驾驶员的接管风险,且模型在表征风险的准确性方面优于碰撞时间倒数。 展开更多
关键词 交通工程 接管风险评估 行车风险场 轨迹数据 自动驾驶 驾驶模拟
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