车头间距分布规律的研究

以我国混合车流作为高等级公路交通流的基本构成,分析了混合车流车型跟驶序列组合的概率;采用计算机模拟手段,得到了车头时距阈值与速度关系、不同跟车序列最小车头间距、车头间距与随机度关系和车头间距与流量关系;并通过随机度参数将微观和宏观参数整合为一体。     

一种带方向锁定的移动通信信道借用指配策略

介绍了一种蜂容移动通信系统中基于紧凑模式的信道借用指配策略（CPCB）的优化策略－－基于紧凑模式带方式锁定的信道借用指配策略（C‘CBDL）,这 策略不仅将带方向锁定的优点引入到CPCB策略中,而且优化了信道策略管理机制,将新算法在一种普遍采用的蜂窝网络上进行仿真,分别获得了在一种均匀和两种非均匀模式业务分布下的系统性能,结果表明,CPCBDL的系统性能不仅明显优于FCA,BDCL和基于CP的DCA等策略,也优于CPCB策略,这对于提高蜂窝移动系统的频谱利用率和业务吞吐能力均有十分重要的意义。     

考虑时间因素的运输方式选择问题

本文先对各类运输方式做了概括论述,在着重考虑时间因索的前提下对运输方式的选 择进行了定量分析,提出了利用最小花费来完成运输任务的运输方式选择模型,并分析了该摸 型的求解过程,有助干运输消费者选择经济、合理的运输方式。     

物流发展与评价

作为当代市场经济发展中,工业、商业和运输业触合的一种新兴产业组织模式— 现代 物流,正受到广泛关注,如何通过分析其不断演化和拓展过程中的基本规律,寻求其内在联系. 本文对迄今为止的物流概念与物流实践的发展进行了基本考察.对物流的基本涵义,早期提出的物流概念如何不断演化与拓展,以及什么是现代物流,物流现代化的必要因素,从传统物流到现代物流的进程可以划分为几个典型阶段,呈现怎样的路径依赖等给出了基本答案。     

列车控制仿真系统中速度控制曲线的计算

在介绍列车控制系统结构和列车速度控制模式的基础上,重点阐述列车控制仿真中列车速度控制模式的曲线的计算方法.目次,整个列车控制仿真系统已经投入运行,并取得了预期的效果.     

变频器的合理选用

结合理论与实践,全面论述了变频器的合理选择与使用方面的有关问题,包括变频器容量与型式的选择,使用频率与起停时间的设置,以及和其它调速方法的结合.     

Mining and correlating traffic events from human sensor observations with official transport data using self-organizing-maps

Cities are complex systems, where related Human activities are increasingly difficult to explore within. In order to understand urban processes and to gain deeper knowledge about cities, the potential of location-based social networks like Twitter could be used a promising example to explore latent relationships of underlying mobility patterns. In this paper, we therefore present an approach using a geographic self-organizing map (Geo-SOM) to uncover and compare previously unseen patterns from social media and authoritative data. The results, which we validated with Live Traffic Disruption (TIMS) feeds from Transport for London, show that the observed geospatial and temporal patterns between special events (r = 0.73), traffic incidents (r = 0.59) and hazard disruptions (r = 0.41) from TIMS, are strongly correlated with traffic-related, georeferenced tweets. Hence, we conclude that tweets can be used as a proxy indicator to detect collective mobility events and may help to provide stakeholders and decision makers with complementary information on complex mobility processes.     

Gender differentials in travel pattern – The case of a mid-sized city,Rajkot, India

This paper is at the conjunction of arguments for gender equity in transport services on one hand and need to move towards low carbon transport on the other in a developing country city. The case study city, Rajkot, a mid-sized Indian city with mixed land use and limited public transport at the time of this study, has short trip lengths and low trip rates. But, even in this city there is gender disparity in travel pattern. Thus, trip rates and trip lengths of women in the city in each of the income group are lower than that of their male counter parts. With the increase in income, both, the trip rates and lengths increase, but, the increase is higher for men than for women. While the large proportions of women in each income group walk, that among the lowest income group walking is the predominant mode, as they are ‘no-choice’ or ‘forced’ walkers. With the increase in household income, women tend to shift to para-transit and men to personal motorized transport. If sustainability arguments or climate policies are to target retaining the current low ecological footprint of the women as one of the strategies, it needs to cater to expansion of their mobility while improving infrastructure to support the same.     

基于关系代数的结构模式识别系统句法分析单元设计

介绍了一种基于关系代数的句法分析单元设计.尝试通过与关系代数模型紧密集成,利用关系数据库系统能够组织和快速检索海量数据的特点,提高句法分析单元的处理复杂文法样本的能力,同时减轻用户的编码负担.在此框架中,部分推导树集合被表示为关系；推理规则集被表示为扩展的关系代数运算.给出了算法实现所需的数据结构和控制结构.从而将句法分析算法完全表示为数据库系统中的一个关系运算过程.最后通过原型系统验证了该方法的可行性.     

Origin-destination pattern estimation based on trajectory reconstruction using automatic license plate recognition data

Origin-destination (OD) pattern estimation is a vital step for traffic simulation applications and active urban traffic management. Many methods have been proposed to estimate OD patterns based on different data sources, such as GPS data and automatic license plate recognition (ALPR) data. These data can be used to identify vehicle IDs and estimate their trajectories by matching vehicles identified by different sensors across the network. OD pattern estimation using ALPR data remains a challenge in real-life applications due to the difficulty in reconstructing vehicle trajectories. This paper proposes an offline method for historical OD pattern estimation based on ALPR data. A particle filter is used to estimate the probability of a vehicle’s trajectory from all possible candidate trajectories. The initial particles are generated by searching potential paths in a pre-determined area based on the time geography theory. Then, the path flow estimation process is conducted through dividing the reconstructed complete trajectories of all detected vehicles into multiple trips. Finally, the OD patterns are estimated by adding up the path flows with the same ODs. The proposed method was implemented on a real-world traffic network in Kunshan, China and verified through a calibrated microscopic traffic simulation model. The results show that the MAPEs of the OD estimation are lower than 19%. Further investigation shows that there exists a minimum required ALPR sampling rate (60% in the test network) for accurately estimating the OD patterns. The findings of this study demonstrate the effectiveness of the proposed method in OD pattern estimation.