基于注意力机制及分层网络的危险驾驶行为预测方法

基于自然驾驶实验,获取“人-车-环境”多维驾驶行为数据,经过数据清洗与筛选构建危险驾驶行为标准数据库。采用显著性分析对指标进行筛选,并构建八维度的危险驾驶行为预测指标集。以神经网络为第一层,以基于注意力机制的长短期记忆（LSTM）网络为第二层,建立危险驾驶行为预测双层时序模型。结果表明：该模型能有效提升预测准确率（10%）;分层结构和注意力机制对预测准确率有较好的提升作用,分别为5%和3%。     

基于超距雷达数据的车辆跟驰行为分析及建模

针对高速公路车辆跟驰特性及速度预测问题,基于超距雷达数据分析了高速公路车辆跟驰特性,建立起基于长短期记忆（long short term memory,LSTM）的跟驰速度预测模型。首先,根据数据特点建立了处理规则并筛选跟驰序列。其次,根据车身长度将跟驰车划为大型车与小型车,分析了车辆在跟驰过程中速度、车速差、车间距和车头时距等参数的分布及相对变化关系。然后,将前车速度、位置差、上一时刻车头时距作为模型输入,跟驰车速度作为模型输出,构建了基于LSTM的跟驰速度预测模型,模型预测精度达到99.75%。最后,以高速公路数据为例进行验证,传统机器学习支持向量回归（support vector regression,SVR）模型的预测性能低于深度学习模型,LSTM模型的R Square较SVR模型提升了4.37%;作为LSTM的结构简化变体,在相同的结构参数下,门控循环单元（gated recurrent unit,GRU）模型的预测性能并未提升,但训练速度较LSTM模型提高了28.48%。深度学习LSTM、GRU模型能够更精准地预测高速公路的车辆跟驰速度。     

基于Copula模型的机翼结冰飞行风险定量评估方法研究

结冰条件下飞行风险定量评估可以为飞机结冰适航验证提供参考指标。提出了极值理论与Copular模型相结合的机翼结冰条件下风险定量评估方法。基于人 机 环复杂动力学模型进行蒙特卡罗仿真实验,提取了关键飞行参数（空速、滚转角和迎角）极值。利用辨识得到的参数进行拟合优度检验,验证了Joe Copula模型能够较为准确描述三维极值参数联合分布形式。通过建立的风险概率判据计算了飞行风险概率,分析表明结冰风险事件往往伴随着飞行安全关键参数不同程度的超限和耦合影响。所提方法可为结冰条件下的飞行风险定量评估和预测管控提供理论参考依据。     

基于LSTM-XGboost组合的超短期风电功率预测方法

受数值天气预报信息影响,风电功率变化具有较强的随机波动性,传统单一预测模型精度较低,难以满足现实预测需求。为此,提出基于LSTM-XGboost组合的超短期风电功率预测方法。首先,基于风电场的气象数据,采用皮尔逊相关系数法筛选与风电功率强相关的气象数据,建立风电功率预测模型数据集;然后,将归一化处理的数据集作为LSTM(long short-term memory)和XGboost (extreme gradient boosting)的模型输入,分别构建LSTM和XGboost的超短期风电预测模型,在此基础上,采用误差倒数法对LSTM和XGboost的预测数据进行加权构建组合预测模型;最后,以张家口某示范工程风电场实际运行数据验证组合模型的有效性。结果表明,相较于其他4种单一预测模型,组合模型具有更高的预测精度。     

基于Attention机制的CNN-LSTM驾驶人意图识别方法研究

在自动驾驶系统中，系统需要准确识别驾驶人的意图，来帮助驾驶人在复杂的交通场景中安全驾驶。针对目前驾驶人意图识别准确率低，没有考虑优化特征对模型准确率影响的问题，运用深度学习知识，提出了一种基于时间序列模型的驾驶人意图识别方法。该方法基于Attention机制融合了卷积神经网络(convolutional neural networks, CNN)和长短时记忆网络(long short-term memory network,LSTM),引入车辆自身信息和环境信息作为时空输入来捕捉周围车辆的空间交互和时间演化。该方法可同时预测目标车辆驾驶人横向驾驶意图和纵向驾驶意图，并在实际道路数据集NGSIM(next generation simulation)上进行了训练和验证。实验结果表明，所提出的CNN-LSTM-Attention模型能够准确预测高速公路环境下驾驶人的驾驶意图，与LSTM模型和CNN-LSTM模型相比具有明显的优势，为自动驾驶系统的安全运行提供了有效保障。     

GPS数据驱动的车辆跟驰行为建模与分析

为研究道路交通流特性,基于车载高精度GPS跟驰试验数据进行车辆跟驰建模研究,结合深度学习理论和数据驱动方法,构建了基于粒子群优化(particle swarm optimization, PSO)的长短期记忆(long short term memory, LSTM)车辆跟驰模型。首先,清洗和平滑车辆轨迹数据,并对驾驶特征行为参数及相关关系进行研究,如加速度、车头时距以及速度与跟驰距离特性关系等。在此基础上,制定跟驰状态筛选规则;其次,构建考虑时间序列的PSO-LSTM模型,识别跟驰数据样本集,将当前时刻的前车速度、车头间距和上一时刻的车头时距作为模型输入,预测当前时刻的跟驰车速度;接着,选用25辆车跟驰试验的高精度GPS数据验证PSO-LSTM模型性能;最后,为验证该模型的优越性,选用传统机器学习SVR(support vector regression)模型以及深度学习LSTM模型作为对比。结果表明,基于粒子群优化的长短期记忆模型预测精度高达0.993,整体预测效果高于SVR模型和LSTM模型,其中预测误差指标MAPE(mean absolute percentage error)较SVR和LSTM分别降低了60.02%、1.52%。PSO算法进行超参数优化后的PSO-LSTM模型,能更好地模拟车辆的跟驰行为。     

LSTM模型在耕地面积预测领域的构建与应用

 长短期记忆（LSTM）模型广泛应用于系统故障、交通流量、股票指数、紧急事件、碳排放、石油产量、农区地下水位等多个领域,均表现了出色的预测性能。为了丰富耕地面积预测方法、提升耕地预测精度,将LSTM模型引入耕地面积预测。选择常用的趋势外推模型、指数平滑模型、灰色模型、移动平均自回归、支持向量机、NAR动态神经网络等6类模型进行对比,并以耕地变化趋势比较复杂的黑龙江省和变化趋势比较单一的辽宁省、吉林省作为案例进行分析,以验证LSTM模型耕地面积预测效果。结果表明,从均方根误差（RMSE）、平均绝对误差（MAPE）这2个指标的综合评价来看, LSTM模型拟合和预测效果均为最优。根据LSTM模型预测, 2018-2030年黑龙江、吉林、辽宁3省的耕地面积将呈持续减少的趋势,耕地减少速度均有放缓之势。     

综采工作面瓦斯爆炸风险评估

针对瓦斯涌出预测及风险评估过程时使用方法单一的问题,文章提出一种基于LSTM的综采工作面瓦斯涌出预测及风险评估方法。首先采用拉依达准则和拉格朗日插值法对原始的瓦斯浓度数据进行异常值和缺失值处理,其次选取均方误差作为模型的评价指标,利用适应性矩估计优化算法通过一阶偏差、二阶偏差校正对模型中的参数进行优化,最终通过训练建立LSTM的煤矿工作面瓦斯浓度预测模型。结果表明：以某矿综采工作面监测数据为例,利用“3σ”准则实现瓦斯爆炸风险等级划分,分别采用SVM支持向量机、BP神经网络和LSTM神经网络对瓦斯爆炸风险等级进行评估,通过对比3种模型的训练误差和预测值发现LSTM神经网络的风险评估误差较小,预测值准确度更高,具有更好的实用价值。     

单车道手动-自动驾驶混合交通流仿真分析

随着汽车产业和交通行业的快速发展,智能交通取得了长足进步,尤其是在自动驾驶领域。为研究手动驾驶、自适应巡航控制(adaptive cruise control, ACC)和协同自适应巡航控制(cooperative adaptive cruise control, CACC)三类车辆独立存在时的单车道交通流运行特性,基于元胞自动机Nasch规则,引入Gipps安全间距和速度,分别构建跟车模型,通过数值仿真试验,分析混入ACC和CACC车辆对道路通行能力、行驶速度、行车间距、交通拥堵等运行特性的影响。结果表明：随着ACC和CACC车辆渗透率的增加,道路通行能力和车辆行驶速度不断提高;当道路仅由数量相等的ACC和CACC车辆驾驶时,通行能力可提升2.2倍,拥堵指数可降低60%,显著改善了交通运行;引入ACC和CACC车辆增大了手动驾驶车辆行驶时的跟车间距,而ACC和CACC车辆仍能以较小的间距保持较高的速度跟随前车,提高了道路空间资源利用率。     

基于概率计算的车辆碰撞风险模型研究

 为研究面向车辆防撞系统的碰撞风险模型,分析了车辆碰撞风险的概率内涵,根据运动学理论并考虑车辆运行特征,建立了基于概率计算的侧向碰撞风险模型,运用Vissim微观交通仿真等方法模拟常见的车辆运行场景,利用输出数据离线计算风险值,并对仿真结果进行评价。将追尾碰撞发生的过程分为前车减速与前车减速条件下的碰撞两起事件,运用条件概率的思想求出追尾事故发生的概率来表征跟车风险。从安全的本质出发提出了跟车风险的表述方法,建立密度函数模型。在分析前车减速条件下追尾碰撞条件时,从汽车地面力学理论的角度补充考虑了制动系统作用时间、附着系数等影响因素,使模型更接近实际状况,并且将判断的标准由停车距离扩展到了制动全过程的位移。通过与其他风险模型产生的计算结果进行比较分析,发现基于概率计算的碰撞风险模型,能够更好地反映实际交通安全状态,更适用于车辆防碰撞系统。     

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.     

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.     

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.     

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