Online calibration for microscopic traffic simulation and dynamic multi-step prediction of traffic speed

Simulating driving behavior in high accuracy allows short-term prediction of traffic parameters, such as speeds and travel times, which are basic components of Advanced Traveler Information Systems (ATIS). Models with static parameters are often unable to respond to varying traffic conditions and simulate effectively the corresponding driving behavior. It has therefore been widely accepted that the model parameters vary in multiple dimensions, including across individual drivers, but also spatially across the network and temporally. While typically on-line, predictive models are macroscopic or mesoscopic, due to computational and data considerations, nowadays microscopic models are becoming increasingly practical for dynamic applications. In this research, we develop a methodology for online calibration of microscopic traffic simulation models for dynamic multi-step prediction of traffic measures, and apply it to car-following models, one of the key models in microscopic traffic simulation models. The methodology is illustrated using real trajectory data available from an experiment conducted in Naples, using a well-established car-following model. The performance of the application with the dynamic model parameters consistently outperforms the corresponding static calibrated model in all cases, and leads to less than 10% error in speed prediction even for ten steps into the future, in all considered data-sets.     

船舶中央冷却水系统变频水泵流量特性

针对船舶中央冷却水系统变频水泵切换效率低、能耗大及流量波动变化等问题,深入研究2350TEU集装箱船在各种负荷变化和海水环境温度变化时的变频泵调速流量特性,分析变频水泵在单泵、双泵2种状态切换时的流量特性、效率特性和功率特性,计算水泵变频切换时的最佳转速与流量。结果表明:实现单双泵无扰动切换,可减少切换时流量产生波动对止回阀的冲击,提高变频泵的工作效率,降低系统能耗,为船舶中央冷却水节能控制系统设计提供理论支持。     

Eco-driving advisory strategies for a platoon of mixed gasoline and electric vehicles in a connected vehicle system

As electric vehicles (EVs) have gained an increasing market penetration rate, the traffic on urban roads will tend to be a mix of traditional gasoline vehicles (GVs) and EVs. These two types of vehicles have different energy consumption characteristics, especially the high energy efficiency and energy recuperation system of EVs. When GVs and EVs form a platoon that is recognized as an energy-friendly traffic pattern, it is critical to holistically consider the energy consumption characteristics of all vehicles to maximize the energy efficiency benefit of platooning. To tackle this issue, this paper develops an optimal control model as a foundation to provide eco-driving suggestions to the mixed-traffic platoon. The proposed model leverages the promising connected vehicle technology assuming that the speed advisory system can obtain the information on the characteristics of all platoon vehicles. To enhance the model applicability, the study proposes two eco-driving advisory strategies based on the developed optimal control model. One strategy provides the lead vehicle an acceleration profile, while the other provides a set of targeted cruising speeds. The acceleration-based eco-driving advisory strategy is suitable for platoons with an automated leader, and the speed-based advisory strategy is more friendly for platoons with a human-operated leader. Results of numerical experiments demonstrate the significance when the eco-driving advisory system holistically considers energy consumption characteristics of platoon vehicles.     

一种特殊工况下动车组滑行问题分析和对策研究

通过对运营列车停车情况的分析,从停车原因、速度变化过程、轮轴之间速度差异等几个方面,深入论述了滑行现象产生及速度采集不均衡对行车控制的影响,提出车辆防滑控制、速度均衡优化的应对策略,为有效解决此类问题提供重要参考.     

The effects of emission control area regulations on cruise shipping

To control SOx, NOx and particulate matter emission from ships, including cruise ships, emission control areas (ECAs) have been defined by the International Maritime Organization (IMO), which influences cruise planning. This paper investigates a mixed integer programming model to reschedule voyage plans by optimizing speeds, sailing patterns and ports-of-call sequences, hence reducing fuel costs. A tabu search based solution method is developed to solve the model. Computational tests on real-world data of cruise lines are conducted in order to explore the effects of ECA regulations on cruise shipping. The results show that the proposed model can save fuel costs under ECA regulations, and the designed solution method is efficient.     

振动减速带的速度控制效果研究

车速是影响道路交通安全的一个重要因素，提高速度控制技术的功效，对于改善道路安全性具有重要的意义。文章通过对振动减速带的车辆速度进行观测和分析，评价了速度控制设施的减速效果。     

基于轨间电缆的城市轨道列车速度控制系统

分析了基于轨间电缆的城市轨道列车速度控制系统结构及设计要求，通过对系统的基本原理的论述，提出了一种较为适合我国城市轨道交通发展的速度控制方式。     

船艇波浪中自航试验研究

对一艘船艇作了波浪中自航试验研究，得到了规则波中自航因子变化曲线，用直接功率法作了失速预报，并用谱分析法预报了该艇的纵摇、升沉及螺旋桨出水概率。本文的重要结论：船艇在波浪中的自航因子在简化处理时，可以认为相当于静水中的自航因子。     

苏锡常及上海地区区域沉降对京沪高速铁路的影响及防治对策

研究目的:苏锡常地区及上海地区区域沉降和地基土特别是深厚软土、松软土区轨下基础工后沉降问题,是影响《时速300～350 km客运专线铁路设计暂行规定》高标准工后沉降量控制的主要问题。本文就京沪高速铁路苏锡常及上海地区区域地面沉降的机理及其影响进行研究和分析,并提出相关对策。研究结果:通过对苏锡常及上海地区区域地面沉降的机理及其影响的研究和分析,提出通过合理控制地下水的开采,建立地面沉降监测网络,针对区域沉降对不同的工程类型的影响,优化施工设计采用不同的工程措施综合处理等对策,以满足高标准工后沉降量的控制,达到京沪高速铁路安全、舒适、平稳性的高标准要求。     

既有线提速200 km·h-1的线路区间通过能力分析

在既有线旅客列车最高运行速度提高到200 km.h-1,货物列车最高运行速度提高到100,120 km.h-1条件下,逐一分析追踪列车间隔时间、列车连发比例、列车区间运行时分之差、维修天窗时间等因素对线路通过能力的影响。由分析可知,追踪列车间隔时间货物列车可压缩为7,6 min,旅客列车可压缩为6,5 min;旅客列车比例提高,有利于组织列车群发;客货列车速差变小,有利于列车区间运行时分之差减小。均对提高线路区间通过能力产生有利的影响。但综合维修天窗时间延长,对线路区间通过能力产生负面影响。在此基础上设定基础方案、过渡方案和目标方案,运用直接计算法计算各方案的线路通过能力值,构建两个综合比较方案。通过综合分析,若天窗预留时间延长至180 min,线路区间通过能力可提高约20%。若天窗预留时间延长至240 min,线路区间通过能力可提高约13%。为使线路通过能力保持不变或改善,提出应加快货车提速改造、减少并尽量统一列车标尺,以及研究优化相关作业组织和车底运用方式的建议。