侧向碰撞风险对交织区汇合行为的影响

为研究高速公路交织区匝道车辆的汇合行为,基于梯度提升决策树(Gradient Boosting Decision Tree, GBDT)构建了交织区汇合加速度模型,利用美国 Next Generation Simulation (NGSIM)车辆轨迹数据提取汇合车辆与周围车辆之间的横纵向距离差、速度差及加速度等交通 参数作为候选变量,将1 s后的汇合加速度作为预测变量,对模型进行五重交叉训练和测试,获取 模型最佳参数组合,引入横向距离碰撞时间 TC 分析汇合过程中侧向碰撞风险对汇合加速度的影 响。研究发现：与基于视角的刺激-反应模型(VASR)相比,本文模型的预测精度更高;引入变量 TC 在均方误差(MSE)、平均绝对偏差(MAD)和R2这3个指标上均优于原模型;在各影响变量之中,汇 合车辆与目标车道领车的速度差 ΔVPL 和横向距离碰撞时间 TC 对汇合加速度的影响最大,相对影 响程度分别达到20.2%和12.1%。研究发现,GBDT模型能够准确预测车辆汇合加速度,深入挖掘 变量和汇合加速度之间的非线性关系,引入变量 TC 能够有效提高模型精度。     

TA2钛合金焊接试验研究

通过对TA2钛合金焊接特点的分析,优选合理的焊接工艺、气体保护方式和焊接规范进行试验,试验数据证明采用TIG焊焊接TA2钛合金钢不仅焊缝成型好,微观组织及力学性能也达到了相关标准要求.文章还给出了钛及钛合金的焊接保护焊接区域免受空气侵蚀的相关观点.     

能见度不良水域船舶航行操作要点

结合一例能见度不良时的重大船舶碰撞事故，借助数学模型分析事故发生的原因，提出船舶在能见度不良的水域航行时，应严格遵守雾航准则，正确使用雷达，并强调提高船员业务素质，重视一切可引发事故的因素。     

13号上作用式车钩防跳锁方案设计

通过对13号上作用式车钩防跳机理的分析,得出其失效的原因;根据三杆机构直立不稳定原理,对车钩防跳锁组件进行了结构改造,设计出三连件防跳装置。     

Development of advanced driver assistance systems with vehicle hardware-in-the-loop simulations

This paper presents a new method for the design and validation of advanced driver assistance systems (ADASs). With vehicle hardware-in-the-loop (VEHIL) simulations, the development process, and more specifically the validation phase, of intelligent vehicles is carried out safer, cheaper, and is more manageable. In the VEHIL laboratory, a full-scale ADAS-equipped vehicle is set up in a hardware-in-the-loop simulation environment, where a chassis dynamometer is used to emulate the road interaction and robot vehicles to represent other traffic. In this controlled environment, the performance and dependability of an ADAS is tested to great accuracy and reliability. The working principle and the added value of VEHIL are demonstrated with test results of an adaptive cruise control and a forward collision warning system. On the basis of the 'V' diagram, the position of VEHIL in the development process of ADASs is illustrated.     

对口法的"减牵"优化研究

以对口法的”减牵”优化为目标，引入“入线步长”的概念，在分析确定其递变规律的基础上，指出可编顺组号数界限值遵循“入线步长”变化规律而形成菲波纳契数列的实质；通过研究“固定空元位”的合理取定方法，明确“取空区”的构成，发现其数量变化规律及该规律与入线步长变化规律的异同；基于上述研究，提出构建“减牵”入线结构、使对口法减少作业过程次数的优化方法，确定出可编顺组号数界限值新的分布状态，体现调车作业量与可编顺组号数界限值之间更为准确的对应关系。通过分析在不同作业过程实现“减牵”而出现的作业特点，确定出相对有利的“减牵”优化环节，从而减少入线结构备选方案，使优化进程加快。深化研究后，进一步提出“双减牵”优化的方法及其采用条件，使优化达到更高水平。用实例描述本研究给出的各优化过程，验证了优化结果。指出对口法和消逆法这两种主要的入线算法，在一定条件下经优化改进后而发生的趋同化现象。     

滗水器排水过程的水力学研究

对滗水器的水力模型进行研究，提出滗水器排水流速和时间的理论计算方法，最后以滗水器样机流量的实测值与理论计算值作比较，结果表明，本文提出的理论计算方法是正确的。     

Efficiency Loss of the Multiclass Stochastic Traffic Equilibrium Assignment with Fixed Demand

There exists efficiency loss when introducing a user equilibrium traffic assignment in comparison with the system optimization assignment. Seeking the upper bound of the efficiency loss has attracted many scholars' attentions. The existing researches mainly focus on single user class and deterministic traffic assignment, few on stochastic user equilibrium (SUE) assignment with multiple user classes. In this paper, the authors investigate the upper bound of this SUE's inefficiency. Two decision-making criteria are used in the SUE, namely, time-based and monetary-based. It is shown that the upper bound of efficiency loss caused by the time-based SUE depends on the type of link travel time function, the network complexity, the travel demand, and the degree of users' perception error to travel cost. The upper bound of efficiency loss caused by the monetary-based SUE depends on the value of time of user classes besides the aforementioned factors.     

制动缸数据采集无线传输系统的研制

介绍了制动缸数据采集无线传输系统的设计方案及制动缸压力数据采集、制动缸活塞行程的测量、无线传输等主要电路和系统软件的设计。     

货车L型制动梁磨耗套铆钉机的研制

对货车L型制动梁磨耗套铆钉机的设计方案、主要技术参数和技术特点进行了介绍。