Origin–destination synthesis for aviation network data: examining hub operations in the domestic and international US markets

Hub‐and‐spoke networking is a key feature of current aviation markets in which hubs, as connecting points, function to consolidate and redistribute flows. This indicates that observation of traffic on a segment does not necessarily convey information about the origin to destination routing of passenger journeys because of the unavoidable detours in the system. This paper examines the heterogeneity of the flow composition in domestic and international US markets, which in turn allows us to observe the variation of operations across major hubs. A modified Route Flow Estimator for origin–destination synthesis (or origin–destination matrix estimation) is designed to decompose the segment traffic into itinerary‐based passenger trips. Several public and commercial databases, which are easily accessible, are exploited (and reconciled) for the model in order to (i) generate possible trip itineraries using those segment markets, and (ii) link data‐driven operational conditions with the underlying segment flows. The results are validated with US domestic trip observations and empirical knowledge related to the air transportation system. Then, the variability of the hub operations is examined based on sensitivity tests using the model parameters. From the resolution of itinerary‐based estimates, we observe that major airports' hub operations are spatially uneven, particularly with respect to domestic and international connecting passengers. Copyright © 2017 John Wiley & Sons, Ltd.     

基于PFV策略的连续型元胞自动机交通流模型

科学合理的微观交通流仿真模型是研究交通控制手段有效性的关键.本文结合一种考虑驾驶员视野内前后多车影响的跟驰策略，建立了连续型元胞自动机交通流模型.仿真实验表明，仿真数据与实测数据有较好的拟合性，仿真得到的 K-Q、K-V和 Q-V图能较好地反映实际道路交通流的失稳现象，所建立的模型具有适应不同场景的兼容性与灵活性，能够作为研究我国实际道路交通流问题的仿真工具.     

基于宏观基本图的路网多子区状态一致协同控制

针对基于宏观基本图(MFD)的路网多子区协同控制未考虑各子区拥堵状态差异性及均衡性的问题，本文提出以多子区状态可达一致为目标的子区边界状态反馈控制设计方法. 首先，基于路网 MFD模型建立路网多子区协同模型；进一步，基于部分变量稳定性理论，设计多子区状态可达一致的边界状态反馈控制律.在此基础上，考虑子区拥堵状态的差异性，设计了子区间的协同控制策略，快速缓解子区拥堵状态；同时，提出子区边界输入流的分配优化策略.最后，以潍坊市实际路网为背景建立仿真模型.实验结果表明，本文方法可实现子区交通流分布的均衡性，快速缓解子区拥堵状态，较大幅度地提升路网运行效率.     

Asynchronous n-step Q-learning adaptive traffic signal control

Ensuring transportation systems are efficient is a priority for modern society. Intersection traffic signal control can be modeled as a sequential decision-making problem. To learn how to make the best decisions, we apply reinforcement learning techniques with function approximation to train an adaptive traffic signal controller. We use the asynchronous n-step Q-learning algorithm with a two hidden layer artificial neural network as our reinforcement learning agent. A dynamic, stochastic rush hour simulation is developed to test the agent’s performance. Compared against traditional loop detector actuated and linear Q-learning traffic signal control methods, our reinforcement learning model develops a superior control policy, reducing mean total delay by up 40% without compromising throughput. However, we find our proposed model slightly increases delay for left turning vehicles compared to the actuated controller, as a consequence of the reward function, highlighting the need for an appropriate reward function which truly develops the desired policy.     

提高磁浮交通供电系统功率因数的措施

针对上海高速磁浮交通供电系统的滤波、无功补偿设计的特点,分析了供电系统功率因数较低的原因,提出了提高功率因数的技术措施,并分析了该措施的技术、经济效益。最后给出了改进滤波、补偿系统设计的建议。     

面向传染病疫情防控的公共交通运行管理决策支持研究

近年来全球新发重大传染病疫情不断出现，已成为人类社会必须防范应对的重大风险。公共交通在传染病疫情防控过程中承担着阻断病毒传播和保障复工复产的功能，疫情期间公共交通运行管理的决策需求和技术支撑体系与日常情况有显著差异。现有研究多针对公交日常运行决策需求展开，虽有少量针对突发公共事件的应急管理决策支持的研究，但多针对自然灾害和事故灾难场景，无法迁移应用于传染病疫情防控。基于此，以新型冠状病毒肺炎（COVID-19）疫情为例，综合考虑突发公共卫生事件应急管理流程和疫情防控实际情况，系统梳理疫情不同阶段的防控目标和决策需求，提出一种面向传染病疫情防控的公共交通运行管理决策支持系统框架，建立基于公共卫生事件案例库、多源数据融合库、公交数据分析技术库和公交防疫策略库的功能架构，并设计不同功能模块的算法模型。研究以厦门为例，对提出的决策支持系统的功能架构和算法模型进行验证。研究结果表明，构建公交乘客出行链的成功率为89.7%，并可应用于疫情不同阶段的关联客流分析、感染者同乘人员的追溯分析、医护人员等防疫人员的通勤出行识别、公交运行满载率监控等方面。研究成果不仅对传染病疫情防控有实用价值，而且对突发公共事件应急管理决策支持方法亦有理论贡献。     

交通运输企业伦理的基本维度研究

交通运输企业伦理是运输企业在生产经营活动中所确认并遵循的价值观念与行为方式。文章运用抽象方法,对交通运输企业的＂安全、便捷、文明、生态＂四个基本原则进行了深入分析,旨在为运输企业的伦理化运营提供理论指向。     

炭纤维复合叠层铝板的制备工艺和实验研究

综合评论了从ＡＲＡＬＬ发展到新一代复合叠层铝合金板的进展。实验研究了新一代的叠层铝板－－炭纤维复合叠层铝板的制备工艺，并提供了所制备的炭纤维复合叠层铝板的性能。结果表明：这种铝板具有ＡＲＡＬＬ板的各种优点，能改进ＡＲＡＬＬ的一些缺点，它的各种性能指标皆优于铝合金板，因此可望取代高强度铝合金板而广泛应用于各类工程项目之中。