基于SVM的快速路合流区车辆间隙选择模型

通过2种典型快速路合流区车辆行为观测,发现匝道车辆在选择间隙时存在多次超车行为,表明其汇入过程是一个多次决策的动态过程.根据合流过程中车辆速度的变化特性,判定车辆在选择间隙时的决策点并采集决策点处的微观交通流参数.在此基础上比较了2种不同渠化设计下入口匝道车辆汇入行为的差异.考虑到合流车辆不同行为判别所需的关键参数不同,使用2个支持向量机模型(SVM)进行分类,建立了合流区车辆多次决策的间隙选择模型.通过对采集的交通流参数进行训练,SVM模型的预测精度能够达到91%以上,实现预测车辆间隙选择的目的.最后与Logistic回归模型进行比较,结果证明所提出的模型能够获得较高精度.     

基于梯度提升决策树的高速公路交织区汇入模型

为研究高速公路匝道车辆在交织区的汇入行为,基于梯度提升决策树(GBDT)建立了车辆汇入模型,引入超车时间T、拒绝间隙数N以及最大拒绝间隙G_(LR)来分析匝道车辆拒绝相邻间隙并超越主线前车的行为,并利用美国NGSIM项目中的车辆轨迹数据对模型进行训练和测试.结果表明:GBDT的预测精度较分类回归树和二元Logit模型分别提高5.3%和13.3%;引入变量T,N,G_(LR)使GBDT、分类回归树和二元Logit模型的预测精度分别提高6.0%,6.7%和5.3%;GBDT模型中超车时间T在所有变量中重要性值最高.GBDT模型能够准确地预测汇入行为,获得变量与汇入行为间隐藏的非线性关系;引入变量T,N,G_(LR)能够有效提高汇入模型的预测精度.     

快速路入口匝道车辆汇入位置的分布特征分析

为研究快速路入口匝道车辆的汇入行为,首先对交织区全范围的汇入位置进行采集,然后通过聚类分析将汇入行为分为前段汇入、中段汇入、末段汇入3种.采用5种分布模型对各类行为的汇入位置进行拟合,通过最大似然估计法确定模型参数并进行Kolmogorov-Smirnov拟合优度检验,发现前段汇入符合Johnson SB模型,中段汇入符合Log-Logistic模型,末段汇入符合Gen.extreme.value模型.最后,建立汇入位置分布与主路外侧车道密度、匝道车辆合并速度间的关系模型.敏感性分析结果表明,同一类别的汇入位置分布受密度、速度的影响显著.     

定时调节算法与感应调节算法在入口匝道控制的应用

入口匝道控制是快速路交通控制系统中应用最广、效果最好的一种控制形式。首先是控制调节驶入主线的交通流量,使得匝道下游的主线流量不超过其通行能力或服务流量。然后是则主要帮助驶入车辆安全地汇入主线,并尽可能地减少驶入车流对主线车流运行的影响。采用适合的控制算法,则可以减少“挤压”或阻滞,避免出现主线车辆被迫变换车道的情况。控制单位时间内允许进入的车辆数通过从而来消除高速公路上的交通拥挤现象。     

定时调节算法与感应调节算法在入口匝道控制的应用

入口匝道控制是快速路交通控制系统中应用最广、效果最好的一种控制形式。首先是控制调节驶入主线的交通流量,使得匝道下游的主线流量不超过其通行能力或服务流量。然后是则主要帮助驶入车辆安全地汇入主线,并尽可能地减少驶入车流对主线车流运行的影响。采用适合的控制算法,则可以减少"挤压"或阻滞,避免出现主线车辆被迫变换车道的情况。控制单位时间内允许进入的车辆数通过从而来消除高速公路上的交通拥挤现象。     

高速公路加速车道上车辆的汇入特征分析

为了研究高速公路入口匝道上车辆的汇入规律，利用摄像和Autoscope-2004图像处理系统在江苏、山西、河北、北京、天津、广东等地对高速公路合流区加速车道上车辆的汇入特征数据进行了大量调查，在对调查数据进行处理分析的基础上，运用概率分析和微分法建立了匝道车辆的汇入概率模型和行驶距离分布概率模型，利用实际数据对模型进行检验，并举例说明模型在高速公路加速车道长度的设计、评价和分析方面的应用，该模型揭示了匝道车辆汇入概率与合流区几何特征、交通特征的数学关系，不但解释了调查结果，而且对高速公路规划设计、控制管理等工程实践有重要的指导意义。     

山区高速公路紧急避险车道辅助车道设置

通过对8处紧急避险车道主线外侧车道车头时距的收集与分析,运用拟合分析和卡方检验,发现当外侧车道交通流小于500veh·h-1时,车头时距符合负指数分布.考虑主线外侧车道交通流量、失控车辆的速度与失控车辆汇入的临界间隙,应用微分法求导得到失控车辆汇入主线外侧车道的汇入概率模型.通过分析失控车辆汇入主线外侧车道的换车道驾驶行为,得到了不同路面状况下车辆汇入临界间隙.在保证失控车辆95%的汇入成功率条件下,计算不同路面状况、主线外侧交通流量与驶入速度下的辅助车道长度设置值.     

城市高架路下匝道地面联接段最小长度模型

为了提高下匝道地面联结段的系统通行能力,提出了一种计算联结段长度的方法.给出了地面联结段的基本定义及假设,分析了地面联结段构造特性及交通流特性.采用临界安全间隙理论、概率论及运动学方法,综合考虑车辆驶离匝道后汇入地面道路、完成交织运行和顺利驶入下游交叉口左转车道的运行过程,从系统的角度构建下匝道地面联结段的最小长度模型.对于新建道路,根据模型计算可确定联结段的最小长度;对于现有道路,将实测值与模型计算值进行比较,可分析地面联结段产生拥堵原因,便于采取有针对性的改善措施.最后结合实测调查数据,通过与CORSIM仿真模型的输出值进行比较,对模型的正确性进行了验证,结果表明模型是有效的.     

滑坡灾害危险性评价的3种统计方法比较——以深圳市为例

采用Logistic回归模型、广义加法模型(GAM)和分类与回归树(CART)3种统计方法, 对深圳市的研究区域进行了滑坡灾害的危险性评价;利用Kappa值和ROC曲线,结合危险性评价结果图对3种方法的效果进行了比较,并分析了3 种方法在选取主控因子以及确定因子影响程度等方面各自具有的特点。在研究区域的条件下,GAM 的效果优于Logistic回归模型和CART,Logistic回归模型和CART的效果大致相当。Logistic回归模型和CART可自主选择主控因子,通过GAM 可定量研究因子的影响程度以及变化趋势。     

快速路匝道汇入方案优化及软件仿真

针对城市快速路交通压力日益增长,匝道汇入处经常形成拥堵、交通事故频发等现状,结合当前城市快速路现状,通过理论计算和仿真实验方法,对现有汇入方案进行分析和优化,提出了“限速增道”汇入方案.方案在匝道汇入处采取隔离和限制措施,适当减少主、匝道车道宽度,降低车辆速度,引主导、匝道车辆各行其道,减少相互干扰,最终达到提高汇入处通行能力的目的.仿真实验数据显示,方案的单位时间车流量、通行速度、排队长度等交通指标均明显优于其它方案,效果明显.“限速增道”方案在现有车道宽度较宽的城市快速路上可以采用.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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