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21.
本文综合分析了北京城市交通现状,运用生产力布局的理论对北京城市交通拥堵的原因进行分析,探索了国内外大城市交通发展的最新趋势,根据发展“首都经济”的要求.提出解决北京城市交通拥堵问题,必须采取标本兼治,并提出北京城市交通发展战略研究的有关建议。.  相似文献   
22.
结合广东省汕汾高速公路汕头海湾大桥北引道路面加铺工程,分析软基路段过渡性路面的病害,提出沥青混凝土路面罩面结构设计和施工中须注意的问题.  相似文献   
23.
通过毛细水上升高度试验,得出了风积沙在最佳含水量、不同压实度条件下的毛细水上升高度数据;通过室内盐胀试验得到了不同含盐量风积沙的盐胀量,并分析了含盐量及温度与盐胀量的关系。  相似文献   
24.
This paper investigates crowding effect on the path choice of metro passengers. We show people reroute not only to avoid the delay from crowding but also to evade crowding itself. More specifically, a logit model fits best when it uses the transit delay from crowding as well as the passenger load of a connection in addition to the conventional explanatory variables. Also, we demonstrate that crowding decreases the overall welfare of metro passengers. The model is tested on the real path choice data acquired by the recent algorithm by Hong et al. (2015) known to detect the real path choice from Smart Card data in more than 90% of the cases.  相似文献   
25.
随着《铁路基本建设项目投资管理办法》(铁总计统〔2017〕179号)及《关于铁路建设项目清理概算工作的通知》(发改投资电〔2019〕1号)文的出台,标志着铁路建设项目概算清理工作,将逐步交由建设单位按照不突破初步设计批复金额进行处理,因此初步设计阶段如何确保招标预算金额的准确性,体现的越来越为重要,本文通过对500米长轨营业线火车市场运费与编制办法计算运费的分析,量化两者费用存在的差异,列明差异原因,并提出相关建议。  相似文献   
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In the present paper, the Local Joint Flexibility (LJF) of the ring-stiffened X-joints and plate-stiffened X-joints under compressive load is investigated. In the first phase, a finite element (FE) model was generated and verified with the results of available experimental tests and equations. In the next phase, a set number of 234 FE models were created to evaluate the role of the external ring size (βr and τr), the external plate size (βp and τp), and the connection geometry (γ, τ, and β) on the LJF factor (fLJF). In these FE models, the weld connecting the chord and brace members was generated. The results indicated that the fLJF of a plate stiffened joint can be down to 76% of the fLJF of the corresponding un-stiffened joint. Also, the effect of the ring size on the fLJF was more than the effect of the plate size on the fLJF, because of the stiffener position. Despite the notable effect of the ring and the plate on the fLJF, there is not any study or formula on tubular connections stiffened with ring or plate. Therefore, the FE results were used to propose two parametric formulas for determining the fLJF in X-joints with external ring or external plate under brace compressive load. Moreover, the derived formulas were checked based on the UK DoE acceptance criteria.  相似文献   
28.
This study proposes a framework for human-like autonomous car-following planning based on deep reinforcement learning (deep RL). Historical driving data are fed into a simulation environment where an RL agent learns from trial and error interactions based on a reward function that signals how much the agent deviates from the empirical data. Through these interactions, an optimal policy, or car-following model that maps in a human-like way from speed, relative speed between a lead and following vehicle, and inter-vehicle spacing to acceleration of a following vehicle is finally obtained. The model can be continuously updated when more data are fed in. Two thousand car-following periods extracted from the 2015 Shanghai Naturalistic Driving Study were used to train the model and compare its performance with that of traditional and recent data-driven car-following models. As shown by this study’s results, a deep deterministic policy gradient car-following model that uses disparity between simulated and observed speed as the reward function and considers a reaction delay of 1 s, denoted as DDPGvRT, can reproduce human-like car-following behavior with higher accuracy than traditional and recent data-driven car-following models. Specifically, the DDPGvRT model has a spacing validation error of 18% and speed validation error of 5%, which are less than those of other models, including the intelligent driver model, models based on locally weighted regression, and conventional neural network-based models. Moreover, the DDPGvRT demonstrates good capability of generalization to various driving situations and can adapt to different drivers by continuously learning. This study demonstrates that reinforcement learning methodology can offer insight into driver behavior and can contribute to the development of human-like autonomous driving algorithms and traffic-flow models.  相似文献   
29.
结合船舶驾驶员的岗位职责,依照现代职业教育理论和成果,设计了船舶通信英语口语与听力课程标准.对该课程的课程概述、培养目标、与前后课程的联系、教学内容与学时分配、学习资源、教师要求、学习场地与设施要求、考核方式与标准、学习情境设计进行了设计和描述,将船舶通信中典型工作任务转化为学习型任务.  相似文献   
30.
在改革不断深入、经济社会深度转型的当下,大学生群体呈现出新的特点和个性。在新的形势下,要加强高校教风学风建设,更好的发挥高校培养人才的作用,促使人才培养质量提升。本文以辽宁省交通高等专科学校为例,着重从文化建设、教师育人能力提升、学生职业梦想等角度入手,提出了加强教风学风建设的具体举措和途径。  相似文献   
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