基于高速公路空间几何特性的线形协调性设计评价

为对高速公路线形协调性设计进行有效的评价和指导,利用驾驶模拟和实车试验获取车辆运行数据,提出一种基于线形空间几何特性参数拟合的协调性设计评价模型,并给出了指标选用及优化措施。首先,分析了优先进行线形协调性设计的特征指标,以曲率k和挠率τ作为描述高速公路线形空间几何特性的的特征参数。其次,结合驾驶模拟实验和实车试验,通过多元非线性拟合建立一般路段线形设计协调性与曲率差Δk、挠率差Δτ的二元多项式评价模型,并通过调整横断面和安全设施信息对模型进行修正。结果表明,该模型能较好地反映线形指标、横断面信息、交通安全设施与车辆运行状态间的作用关系,为高速公路线形协调性设计和应用研究提供指导。最后,通过反推Δk、Δτ取值范围,提出了指标选取的依据和优化措施。     

混合交通环境下逼近最优换道策略的 无人车驾驶模型

针对无人车在现实交通流中的驾驶行为以及车辆间相互影响机制还不明确的现状,提出逼近最优换道策略的无人车驾驶模型.结合无人车周围的交通环境,引入驾驶行为指标体系,利用层次分析法测算指标权值.基于欧氏距离与灰色关联分析的Topsis(Technique for Order Preference by similarity to an Ideal Solution)法建立驾驶行为决策模型来计算换道最优逼近值,代替随机换道策略驾驶模型中的随机概率值;建立逼近最优换道策略的无人车驾驶模型,利用美国洲际5号公路的实际交通数据对新模型进行数值仿真.结果表明:逼近最优换道策略的无人车驾驶模型明显优于随机换道的无人车驾驶模型,能够改善交通拥堵状况,提高整个道路车辆的行驶速度.     

基于驾驶模拟器的车联网环境搭建及对驾驶行为的影响

为研究网联环境下车载设备对驾驶行为的影响,设计了车载终端人机交互界面,搭建了基于驾驶模拟仓的车、车通信环境,并开展模拟驾驶实验,采集了4个场景下车辆运行数据。通过对速度、加速度、跟车间距、超速驾驶员比例等驾驶行为数据以及人口学的统计分析,研究不同交通状态下,是否配备车载终端对驾驶行为影响的差异性。实验数据表明,实时提供前车运行状态的车载终端能够提高车辆运行效率和安全性。     

基于改进萤火虫算法优化BP神经网络的路网速度分布预测

浮动车数据的挖掘是目前交通领域广泛使用的研究手段之一,基本的BP神经网络也多被用于交通流的预测研究。本文引入小波变换将低频信号和高频信号进行分解和重构,结合改进萤火虫算法寻优速度快、收敛率高的特点对基本的BP神经网络进行优化,构建了路网交通流速度的预测模型。利用城市路网浮动车真实数据对模型进行训练并通过测试数据对模型预测结果进行实证分析,证明模型对特定时刻路网交通流速度预测的准确性相比于基本BP神经网络算法有46.56%的提升,对路网24h内交通流速度预测的稳定性有39.08%的提升。     

基于BP神经网络的纵向避撞安全辅助算法

针对复杂人-车-路交通环境下汽车前向防碰撞预警系统(FCWS)在实际工程应用中存在虚警漏警、可接受性差等问题,为提高FCWS对驾驶群体行为差异的适应性,提出了驾驶员行为特性自适应学习的纵向避撞安全辅助算法,建立了基于BP神经网络的闭环驾驶跟驰习惯模型。该网络模型以跟车车距、前车减速度、前车速度、自车速度、环境亮度、路面附着系数、紧急制动次数、本次驾驶时间为输入,采用动量梯度下降自适应学习率方法对网络模型进行训练,进而预测出自车待制动减速度。引入聚类算法思想,对训练样本集进行特征聚类,进一步改善了BP网络的预测性能,设计了激进、谨慎、新手3类典型驾驶群体,通过制动深度、期望碰撞时间倒数、应急反应时间来表征驾驶群体性特征,在稳态跟车过程中对不同驾驶群体的行为特性进行学习,建立起非线性输入输出映射关系知识库,进而预测出相应群体的待制动行为,实现差异化预警,可有效降低虚警或预警不及时现象。仿真结果表明,改进后的BP网络减小了训练过程中陷入局部极小的可能性,提高了网络收敛速度以及预测精度,激进群体与新手群体待制动曲线下降的趋势相对更陡,激进群体跟车距离相对偏近,新手群体采取制动措施时所需相对车距相对偏远,以补偿较长的反应距离,从而验证了该理论模型对不同驾驶群体的适应性。     

遗传算法优化的方向与速度综合控制驾驶员模型

针对当前驾驶员模型无法体现驾驶操纵熟练程度的缺点,利用遗传算法的自动寻优能力,总结驾驶员自学习与驾驶经验特点,遵循行驶误差最小与体力负担最小原则,对模糊PID比例因子和量化因子进行离线优化设计,以此模拟驾驶员从生手到熟练驾驶培训过程。构建包括遗传算法优化的方向模糊PID与速度模糊综合控制驾驶员模型以及整车行驶动力学模型在内的人车闭环系统仿真模型,在纵向速度单向变化、侧向双移线工况与大曲率试验道路典型工况下进行仿真分析。结果表明：基于遗传算法优化的方向模糊PID与速度模糊综合控制模型可以很好地描述驾驶员在纵向加减速操纵特性以及侧向预期轨迹跟随转向驾驶特性,相比于传统PID与模糊PID控制,具有更好的纵向加减速操纵特性与侧向预期轨迹跟随性能。     

车联网环境下信息交互形式对驾驶行为的影响

为研究车联网环境下不同信息提供方式对驾驶行为的影响,设计了车联网环境下的模拟驾驶实验,采集了4个场景下车辆运行数据。对比不同分心任务的驾驶行为特征和正常驾驶行为的差异,从转向角、车辆侧向偏移、速度、跟车距离等特征参数描述了车联网信息导致分心的驾驶行为规律,并构建了基于模糊综合评价方法的驾驶人分心等级评判模型,横向对比了不同信息提供方式对驾驶行为的影响程度。     

基于驾驶员心率的高速公路纵坡路段驾驶舒适度评价

为了量化分析高速公路纵坡路段的驾驶舒适度,进行实车试验,采集驾驶员心生理数据、道路参数以及车辆运行速度数据。运用傅里叶变换转化驾驶员心率随机信号来研究心率变化的规律。采用偏相关分析,确定上、下坡路段影响驾驶员心率增长率的显著性因素。以交通工程学、人因工程学和心理学为基础,探究坡度和速度差对驾驶员心率增长率的影响,构建了基于心率增长率阈值的驾驶舒适度评价模型。研究结果表明：坡度、速度差与驾驶员心率增长率显著相关,而坡长与驾驶员心率增长呈弱相关;上坡路段行车时驾驶员心率增长率主要分布在15%～32%之间,坡度对驾驶舒适度影响较大;下坡路段行车时驾驶员心率增长率主要分布在15%～35%之间,速度差对驾驶舒适度影响较大。研究结果可为高速公路纵坡路段安全管理提供理论依据。     

基于贝叶斯网络的车辆并线意图识别

为了在多车道行驶场景中准确判断出旁车并线意图,提出了一种基于贝叶斯网络的旁车并线意图识别模型。首先,从运动轨迹数据集中筛选样本构建训练集和测试集,选取特征参数,并利用卡方分裂算法对其进行离散化预处理。其次,在评分搜索的网络结构学习基础上,加入随机抽样来避免局部最优,通过构造接近目标平稳分布的马尔可夫链,多次迭代直到收敛到平稳状态来选取最佳网络结构。然后,使用贝叶斯估计法学习网络参数,搭建基于贝叶斯网络的旁车并线意图识别模型。最后,以测试样本进行验证。验证结果表明:基于贝叶斯网络的旁车并线意图识别模型,对并线样本和直行样本的识别准确率分别高达94.76%和96.38%,具有良好的识别精度。减少任意一个纵向参数的模型识别准确率都大于87%,而减少任意一个横向参数的模型识别准确率都小于76%,横向参数对识别效果的影响力大于纵向参数。     

驾驶员驾驶行为的统计学特性

使用自然驾驶数据研究了驾驶员驾驶行为的统计学特性.选取车辆的纵向加速度、侧向加速度、横摆角速度和速度作为描述驾驶员驾驶行为的特征参数.首先,讨论了驾驶员驾驶行为特性的收敛性.使用核密度估计得到了驾驶行为特征参数的概率分布,使用相对熵描述不同数据集之间分布的差异.接着,使用稳定收敛的数据集研究了驾驶行为特征参数的分布特性.最后,使用驾驶行为特征参数的条件分布研究了它们之间的相互影响.结论包括:前向加速度,制动减速度,侧向加速度,横摆角速度均近似服从帕累托分布;制动减速度或前向加速度增加时,驾驶员的转向操作倾向于更加剧烈,反之亦然;驾驶员制动,加速,和转向操作的剧烈程度随速度增加均先增大后减小.     

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

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。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.