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121.
D. Helbing 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,69(4):569-570
This contribution compares several different approaches allowing one to derive macroscopic traffic equation directly from
microscopic car-following models. While it is shown that some conventional approaches lead to theoretical problems, it is
proposed to use an approach reminding of smoothed particle hydrodynamics to avoid gradient expansions. The derivation circumvents
approximations and, therefore, demonstrates the large range of validity of macroscopic traffic equations, without the need
of averaging over many vehicles. It also gives an expression for the “traffic pressure”, which generalizes previously used
formulas. Furthermore, the method avoids theoretical inconsistencies of macroscopic traffic models, which have been criticized
in the past by Daganzo and others. 相似文献
122.
123.
在一维元胞自动机交通流WWH模型和SDNS模型的基础上,建立了考虑驾驶方式改变的元胞自动机模型(Change-CA模型).具体描述为驾驶员可根据交通环境选择不同的驾驶方式在道路上驾车行驶,以各自的演化规则进行状态更新,同时定义了驾驶方式更新原则.通过计算机数值模拟,发现驾驶方式可变时,模型模拟得到的混合交通流流量较大;保守型驾驶方式对交通流变化的影响随改变概率增大而减少.并且在演化过程中,驾驶方式改变频率的变化趋势与改变概率、安全概率密切相关.与NS模型和SDNS模型相比,Change-CA模型减少了车流
关键词:
交通流
元胞自动机
驾驶方式
计算机数值模拟 相似文献
124.
利用唐等人提出的考虑事故概率的交通流模型[Tang T Q, Huang H J, Xu G 2008 Physica A 387 6845]研究事故发生地点对冲击波和稀疏波的影响,其数值计算结果表明,该模型可以如实地刻画事故对这两种交通波的影响,但这种影响与事故发生地点密切相关.
关键词:
交通事故
冲击波
稀疏波 相似文献
125.
126.
The transport by molecular motors along cytoskeletal filaments is studied theoretically in the presence of static defects.
The movements of single motors are described as biased random walks along the filament as well as binding to and unbinding
from the filament. Three basic types of defects are distinguished, which differ from normal filament sites only in one of
the motors’ transition probabilities. Both stepping defects with a reduced probability for forward steps and unbinding defects
with an increased probability for motor unbinding strongly reduce the velocities and the run lengths of the motors with increasing
defect density. For transport by single motors, binding defects with a reduced probability for motor binding have a relatively
small effect on the transport properties. For cargo transport by motors teams, binding defects also change the effective unbinding
rate of the cargo particles and are expected to have a stronger effect. 相似文献
127.
Magali Mercier 《Journal of Mathematical Analysis and Applications》2009,350(1):369-383
Motivated by the modelling of a roundabout, we are led to study the traffic on a road with points of entry and exit. In this note, we would like to describe the modellisation of a junction and solve the Riemann problem for such a model. More precisely, between each point of discontinuity we use a multi-class extension of the LWR model to describe the evolution of the density of the vehicles, the ‘multi-class’ approach being used in order to distinguish the vehicles after their origin and destination. Then, we treat the points of entry and exit thanks to special boundary conditions that give bounds on the flows of the different types of vehicles. In the case of the one-T road we obtain a result of existence and uniqueness. This first step allows us to obtain a similar result for the n-T road. We describe these results and also some properties of the obtained solutions, in order to see how long this model is valid. 相似文献
128.
将层次分析法(AHP)和数据包络分析(DEA)相结合构建了两种方法的联用评价模式,对使用该方法评价城市交通环境可持续发展水平和后续决策指导方面进行了探讨.该方法对AHP法在多个决策单元定量对比分析和DEA体现决策者偏好方面进行了改善.从影响城市交通环境可持续发展水平的城市综合发展、道路设施水平、交通运输功能和交通环境质量等方面出发,建立了城市交通环境可持续发展评价体系,并应用于深圳市实证分析,通过AHP分析认为深圳市2000~2007年城市交通环境可持续发展水平在波动中缓慢上升,再通过27个城市2005年数据DEA有效性分析和投影分析,得到深圳市在城市交通环境可持续发展方面的总体效率为0.9729,并得到了其要达到DEA有效的调整方案和部分政策建议. 相似文献
129.
Andrew M. Ross 《商业与工业应用随机模型》2009,25(6):769-786
We examine a model of traffic flow on a highway segment, where traffic can be impaired by random incidents (usually, collisions). Using analytical and numerical methods, we show the degree of sensitivity that the model exhibits to the distributions of service times (in the queueing model) and incident clearance times. Its sensitivity to the distribution of time until an incident is much less pronounced. Our analytical methods include an M/Gt/∞ analysis (Gt denotes a service process whose distribution changes with time) and a fluid approximation for an M/M/c queue with general distributions for the incident clearance times. Our numerical methods include M/PH2/c/K models with many servers and with phase‐type distributions for the time until an incident occurs or is cleared. We also investigate different time scalings for the rate of incident occurrence and clearance. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
130.
Hai Yen Thi Phan Takashi Yano Hai Anh Thi Phan Tsuyoshi Nishimura Tetsumi Sato Yoritaka Hashimoto 《Applied Acoustics》2010,71(2):107-114
Vietnam is a developing country in southeast Asia, and its environment has been seriously affected by industrialization and urbanization. In large cities like Hanoi (northern Vietnam) and Ho Chi Minh City (southern Vietnam), noise emission from road traffic has been found to be a serious concern among general public. In 2005 and 2007, two large-scale socio-acoustic surveys of community response to road traffic noise were conducted to investigate human reactions to road traffic noise in these cities; the sample sizes were 1503 people in Hanoi and 1471 in Ho Chi Minh City. The noise exposure levels (Lden) were 70–83 dB in Hanoi and 75–83 dB in Ho Chi Minh City. Noise annoyance was estimated using standardized annoyance scales. For both cities, dose–response relationships were established between Lden and the percentage of highly annoyed respondents. Compared to annoyance responses of European people, Vietnamese were less annoyed by road traffic noise by about 5 dB. Hanoi respondents seemed to be more annoyed by noise than Ho Chi Minh City respondents. Conversation and sleep disturbances were not as serious as expected in either city. Furthermore, window orientation in the home was found to affect activity disturbances. 相似文献