网联交通环境下交叉口进口车道动态配置方法

现有网联交通环境下的优化控制方法未能实现CAV(Connected andAutomatedVehicle)专用车道的动态复合利用,鉴于此,本文考虑交通需求及CAV渗透率的实时变化,以车道组内不同功能车道流率比均衡为约束,交叉口全部车道组流率比之和最小为优化目标,构建基于转换指数的CAV共享车道动态配置方法,提出左转CAVs与直行CAVs复合利用CAV共享车道的控制方法,并设计优化求解流程。基于VISSIM中COM组件开发算法,更新车辆轨迹并在CAV/CHV(Connected Human-drivenVehicle)与信号控制器之间交换信息。仿真结果表明,提出的配置策略增强了交叉口适应实时交通需求的动态调节能力,能在一定程度上改善车均延误。进一步分析表明:CAV渗透率对是否设置CAV共享车道及设置几条车道密切相关;在交叉口进口车道条数为4的情况下,当CAV渗透率小于0.35时,不设置CAV共享车道效果最好;当CAV渗透率介于0.35~0.70时,设置1条CAV共享车道效果最佳;当CAV渗透率超过0.70时,宜设置2条及以上CAV共享车道。本文提出的优化方法适用于网联交通环境下中高CAV渗透率的多车道交叉口。

车联网:物联网在城市交通网络中的应用

阐述了"物联网"和"车辆网"这两个热门概念的内涵和外延。通过分析两者的发展历程、历史沿革和相互关系,比较它们在实际生活中的应用,认为车联网可以看作物联网在城市交通网络中的典型应用,展望了车联网在服务与应用方面的美好愿景。以此为基础,讨论了车联网实现的关键技术,并介绍了一个过渡型构建方案。最后,详细讨论了在物联网和车联网领域里国内外学术研究现状。

基于两级模糊决策的网联车辆换道模型研究

城市机动车保有量的增多,城市交通环境逐渐紧张,车辆的换道往往是为获得更佳的驾驶体验,有效的换道过程在满足自身行驶需求的同时也起到缓解城市交通压力的作用.随着5G网络的应用,设备之间的传输数据的速度以及传输数据量增大,通信程度的增强,网联技术进而逐步应用在车辆运行中.通过车联网技术获取本车辆和周围车辆之间的运动信息,车辆和道路之间的驾驶信息在车载终端可实现有效交互,实现人-车-路之间的信息协作.在采取换道驾驶前对当前交通状况有合理的预判,有效地提高道路的通行效率,进而缓解交通拥堵的程度,同时,换道的安全性也得到保障.

网联环境下考虑驾驶员满意度的车辆换道模型研究

为了实现车辆在道路行驶的自由换道行为,针对车辆在换道时刻未考虑相邻车道的运行状态导致的换道提升效果较小、频繁换道现象的产生,提出基于驾驶员满意度的换道决策方法。最后,采用元胞自动机方法进行了换道模型的仿真分析。

Modeling and Characterizing Internet Backbone Traffic

With enormous growth of the number of Internet users and appearance of new applications, characterization of Internet traffic has attracted more and more attention and has become one of the major challenging issues in telecommunication network over the past few years. In this paper, we study the network traffic pattern of the aggregate traffic and of specific application traffic, especially the popular applications such as P2P, VoIP that contribute most network traffic. Our study verified that majority Internet backbone traffic is contributed by a small portion of users and a power function can be used to approximate the contribution of each user to the overall traffic. We show that P2P applications are the dominant traffic contributor in current Internet Backbone of China. In addition, we selectively present the traffic pattern of different applications in detail.

Markov chain-based platoon recognition model in mixed traffic with human-driven and connected and autonomous vehicles

Many vehicle platoons are interrupted while traveling on roads,especially at urban signalized intersections.One reason for such interruptions is the inability to exchange real-time information between traditional human-driven vehicles and intersection infrastructure.Thus,this paper develops a Markov chain-based model to recognize platoons.A simulation experiment is performed in Vissim based on field data extracted from video recordings to prove the model’s applicability.The videos,recorded with a high-definition camera,contain field driving data from three Tesla vehicles,which can achieve Level 2 autonomous driving.The simulation results show that the recognition rate exceeds 80%when the connected and autonomous vehicle penetration rate is higher than 0.7.Whether a vehicle is upstream or downstream of an intersection also affects the performance of platoon recognition.The platoon recognition model developed in this paper can be used as a signal control input at intersections to reduce the unnecessary interruption of vehicle platoons and improve traffic efficiency.

IOT technology application model research of transportation industry in China

The paper studied the connection between internet of things （lOT） technology and transportation industry. Meanwhile, the definition of IOT in transportation was given. Concerning that many problems occurred during the process of traditional intelligent transportation system, the paper proposed a promising model of lOT in transportation. The advantage of the information utilization model from information to function was confirmed through comparative study. Finally, the model presented that a real interconnection of transportation would be achieved based on the unified information collection. It can greatly save cost on technology transfer, exploit potential value of information, and promote the emergence of a sustainable information service market and the industrial upgrade.

A Novel Audio Event Detection Method for Internet of Things

Recently, the Internet of Things （loT） has attracted more and more attention. Multimedia sensor network plays an important role in the IoT, and audio event detection in the multimedia sensor net- works is one of the most important applications for the Internet of Things. In practice, it is hard to get enough real-world samples to generate the classifi- ers for some special audio events （e.g., car-crash- ing in the smart traffic system）. In this paper, we introduce a TrAdaBoost-based method to solve the above problem. By using the proposed approach, we can train a strong classifier by using only a tiny amount of real-world data and a large number of more easily collected samples （e.g., collected from TV programs）, even when the real-world data is not sufficient to train a model alone. We deploy this ap- proach in a smart traffic system to evaluate its per- formance, and the experiment evaluations demonstrate that our method can achieve satisfying results.

Mitigation Strategy against Cascading Failures on Social Networks

Cascading failures are common phenomena in many of real-world networks,such as power grids,Internet,transportation networks and social networks.It's worth noting that once one or a few users on a social network are unavailable for some reasons,they are more likely to influence a large portion of social network.Therefore,an effective mitigation strategy is very critical for avoiding or reducing the impact of cascading failures.In this paper,we firstly quantify the user loads and construct the processes of cascading dynamics,then elaborate the more reasonable mechanism of sharing the extra user loads with considering the features of social networks,and further propose a novel mitigation strategy on social networks against cascading failures.Based on the realworld social network datasets,we evaluate the effectiveness and efficiency of the novel mitigation strategy.The experimental results show that this mitigation strategy can reduce the impact of cascading failures effectively and maintain the network connectivity better with lower cost.These findings are very useful for rationally advertising and may be helpful for avoiding various disasters of cascading failures on many real-world networks.

A Dynamic Bandwidth Allocation Solution Based on User Behavior and Software Defined EPS

For telecommunication operators, how to improve the utilization of bandwidth resources is always a problem which worthy of study, nowadays, this issue has become more and more important, since the traffic load bursting in the mobile Internet. So the key to solving this problem is that we need to find a kind of traffic model to predict the traffic load that users need. According to the predicted traffic load to allocate bandwidth to each base station dynamically.But the traffic consumption behavior of a single base station is random, it is difficult to predict[ 1 ]. For this reason, we based on reality that, when the user moves, it may get traffic load from different base stations, therefore, there will have some kind of relationship between those base stations.We use this relationship to establish a kind of Spatial Collaborative Network.consequently, we make use of stability algorithm to divided those base station cluster into different communities, According to the traffic load usage rules which these communities indicated to us, we get a traffic model.At the same time, we studied bow to use this traffic model in the future networks to dynamically allocate bandwidth resources, then we propose a new kind of EPS architecture based on SDN, on this platform, we can deploy our strategy through it＇s programmable interface.Finally, we designed an experiment to test the performance of our dynamic strategy, and the result shows that our method enables bandwidth utilization has been greatly improved.

Development history and accessibility evolution of land transportation network in Beijing-Tianjin-Hebei region over the past century

From the development of modern transportation to the current era of high-speed transportation networks, the Beijing-Tianjin-Hebei(BTH) region has always played a national leading role in land transportation development of China. In order to explore the long-term evolutionary characteristics of land transportation in the BTH region, this paper utilized a temporal scale of 100 years to systematically interpret the development process of the land transportation network. Taking 13 cities within the BTH region as research anchor cities, we took into account "leaping" mode of transportation in order to investigate the evolution of accessibility. Our research shows the following results:(1) The land transportation network in the BTH region has undergone five stages of development: the initial period of modernization(1881–1937); the period of stagnation of transportation development(1937–1949); the network expansion period(1949–1980); the period of trunk construction(1980–1995), and the period of high-speed transportation network development(1995–present). The network structure centered around Beijing has existed from the outset of modern transportation development.(2) The accessibility spatial pattern of land transportation in BTH region has evolved from expansion along traffic corridors to the formation of concentric circles. The stratified circular structure of transportation in anchor cities has gradually developed into a contiguous development pattern.(3) There are clear hierarchical differences in the transportation structures of anchor cities. Beijing has always been at the top of this hierarchy, while the hierarchical position of Zhangjiakou has fallen noticeably since 1949. The Beijing-Tianjin region was the first region to form a short-duration transportation circle structure, while the transportation advantages of the central part of Hebei Province, which is located in the center of the BTH transportation region, have yet to be realized.

Multi-criterion system optimization model for urban multimodal traffic network

In this paper,computational models of environmental pollution and energy consumption of urban multimodal traffic network are proposed according to pertinent research and a multi-objective programming model is then developed to formulate optimization problem for such a system.Simultaneously,the main factors,such as travel time,pricing and convenience which influence travelers' choice behaviors are all considered and a combined assignment model is proposed to simulate travelers' mode and route choices.A bi-level programming model,in which the multi-objective optimization model is treated as the upper-level problem and the combined assignment model is processed as the lower-level problem,is then presented to solve multi-criterion system optimization problem for urban multimodal traffic network.The solution algorithms of the proposed models are also presented.Finally,the model and its algorithms are illustrated through a simple numerical example.

The Stability of Multi-modal Traffic Network

There is an explicit and implicit assumption in multimodal traffic equilibrium models, that is, if the equilibrium exists, then it will also occur. The assumption is very idealized; in fact, it may be shown that the quite contrary could happen, because in multimodal traffic network, especially in mixed traffic conditions the interaction among traffic modes is asymmetric and the asymmetric interaction may result in the instability of traffic system. In this paper, to study the stability of multimodal traffic system, we respectively present the travel cost function in mixed traffic conditions and in traffic network with dedicated bus lanes. Based on a day-to-day dynamical model, we study the evolution of daily route choice of travelers in multimodal traffic network using 10000 random initial values for different cases. From the results of simulation, it can be concluded that the asymmetric interaction between the cars and buses in mixed traffic conditions can lead the traffic system to instability when traffic demand is larger. We also study the effect of travelers' perception error on the stability of multimodal traffic network. Although the larger perception error can alleviate the effect of interaction between cars and buses and improve the stability of traffic system in mixed traffic conditions, the traffic system also become instable when the traffic demand is larger than a number. For all cases simulated in this study, with the same parameters, traffic system with dedicated bus lane has better stability for traffic demand than that in mixed traffic conditions. We also find that the network with dedicated bus lane has higher portion of travelers by bus than it of mixed traffic network. So it can be concluded that building dedicated bus lane can improve the stability of traffic system and attract more travelers to choose bus reducing the traffic congestion.