A proposed vision and vehicle-to-infrastructure communication-based vehicle positioning approach

It is essential to obtain accurate location of vehicles for new applications of Intelligent Transportation Systems. To remedy the defects of present Global Positioning System and vehicle-to-infrastructure (V-I) positioning technology, a new positioning approach based on vision and V-I communication is proposed. This approach aims at lane-level positioning with lower cost than conventional ones. In this approach, the position of the vehicle is represented by its lateral position (the lane number) and longitudinal position (the distance from entrance of the road) in a course coordinate system along the road; the specific lane the vehicle is occupying (the lane number) can be judged using the information of lane lines detected by vision systems; then the distance to the vehicle is obtained by a Road Side Unit (RSU) during the V-I communication; and the longitudinal position is calculated. The error of the approach on typical operating conditions is analyzed, indicating that the new approach can achieve the accuracy of less than 0.31 m for straight road and 0.58 m for typical arc road with ultra-wideband communication and ranging technologies and rational arrangement of RSUs. The feasibility of this approach is presented.     

Subjective-utility travel time budget modeling in the stochastic traffic network assignment

ABSTRACT

In this article, we propose a new model called subjective-utility travel time budget (SU-TTB) model to capture travelers' risk-averse route choices. In the travel time budget (TTB) and mean-excess travel time (METT) model, a predefined confidence level is needed to capture the risk-aversion in route choice. Due to the day-to-day route travel time variations, the exact confidence level is hard to be predicted. With the SU-TTB model, we assume travelers' confidence level belongs to an interval that they may comply with in the route choice. The two main components of SU-TTB are the utility function and the TTB model. We can show that the SU-TTB can be reduced to the TTB and METT model with proper utility function for the confidence levels. We can also prove its equivalence with our recently proposed nonlinear-expectation route travel time (NERTT) model in some cases and give some new interpretation on the NERTT with this equivalence. Finally, we formulate the SU-TTB model as a variational inequality (VI) problem to model the risk-averse user equilibrium (RAUE), termed as generalized RAUE (GRAUE). The GRAUE is solved via a heuristic gradient projection algorithm, and the model and solution algorithm are demonstrated with the Braess's traffic network and the Nguyen and Dupuis's traffic network.     

Approximate optimal AUTOSAR software components deploying approach for automotive E/E system

The AUTOSAR has been developed as the worldwide standard for automotive E/E software systems, making the electronic components of different suppliers to be employed universally. However, as the number of component-based applications in modern automotive embedded systems grows rapidly and the hardware topology becomes increasingly complex, deploying such large number of components in automotive distributed system in manual way is over-dependent on experience of engineers which in turn is time consuming. Furthermore, the resource limitation and scheduling analysis make the problems more complex for developers to find out an approximate optimal deploying approach in system integration. In this paper, we propose a novel method to deploy the AUTOSAR components onto ECUs with the following features. First, a clustering algorithm is designed for deploying components automatically within relatively low time complexity. Second, a fitness function is designed to balance the ECUs load. The goal of our approach is to minimize the communication cost over all the runnable entities while meeting all corresponding timing constraints and balancing all the ECUs load. The experiment results show that our approach is efficient and has well performance by comparing with other existing methods in specific and synthetic data set.     

钢箱梁桥地震响应的有限元分析

针对典型的工程实例,基于大型有限元软件,采用纤维模型模拟梁柱单元,建立了钢箱梁桥的三维有限元模型,合理选取了强震记录,进行了罕遇地震作用下桥梁结构的弹塑性时程分析,为桥梁结构抗震设计和提高抗震安全性提供了科学依据和重要参考.     

基于ARENA的双车道超车视距设计风险评价

通过计算机仿真软件ARENA模拟双向两车道路段上不同的超车视距长度下的超车行为,并建立风险指标。风险指标主要根据超车动作结束时,超越车与对向车辆间的最短时间距离确定。一共确定了六个风险等级,用于评价不同设计时速下的各种PSD长度的风险。利用此方法可以很直接的评价超车视距设计的优劣。     

昆明市“月月无车日活动”及公众调查分析

调查了解公众对无车日活动常态化这一公共政策的反应,能够为城市交通政策的制定提供一定的技术参考。介绍了昆明市城市交通概况及首个无车日活动成效,同时,对“月月无车日活动”做了概述,在总结前几次活动经验的基础上,给出了活动的进一步调整方案。通过对无车日活动公众调查问卷的数据分析,得出大多数公众对“月月无车日活动”的态度是理解和支持的;在无车日当天,私人小汽车拥有者选择公共交通作为替代小汽车出行方式的比例最高。另外,大力发展公共交通也被受访者认为是解决城市交通拥堵应当首选的措施。     

行人微观仿真中的运动模型与行为模型——STEPS与NOMAD模型对比

为了解各类行人仿真模型的性能差异和适用范围,以选取适当模型进行交通枢纽行人仿真,对两种典型行人仿真模型进行研究。依据模型对行人行为描述的复杂程度,将行人仿真模型分为运动模型、部分行为模型、行为模型3类,并分别介绍了各自的特点。选取典型的运动模型软件STEPS和行为模型软件NOMAD,详细探讨其采用的数学模型,并通过4个仿真实例对比分析这两种模型的特点。分析结果得出两种模型在宏观与微观层面的异同点以及存在的问题。     

公交通行能力约束的智能调度优化模型

公交通行能力是解决城市交通拥堵问题、促进城市公共交通系统高效运行的要素之一。介绍了公交通行能力的计算要素,并针对目前我国城市由于盲目调度造成的公交系统运营效率、服务水平下降的问题,提出将公交通行能力作为约束条件对公交调度进行优化。鉴于公交企业制订调度方案时需兼顾公交服务水平和企业效益,将智能调度的目标确定为候车时间满意度、候车空间满意度、车内舒适满意度和企业满意度加权平均值最大,并给出了相应的计算方法。最后讨论了利用遗传算法对模型进行求解的过程。     

纤维与沥青胶结料的抗拉拔性能评价

通过纤维拉拔试验来评价纤维与沥青胶结料的界面粘结强度,提出了拉拔过程中纤维与沥青胶结料相互作用的受力模型;利用此试验对聚酯纤维和芳纶纤维进行了试验研究,分析了影响界面粘结强度的主要因素,给出了沥青混合料中纤维的合理长度。     

SBS改性沥青混合料配合比设计及施工

在良好的设计配合比和施工条件下,SBS沥青能使沥青路面的耐久性和高温稳定性明显提高.根据南二路的施工试验情况,简要讲述SBS改性沥青的施工技术要求.