浅谈高速公路排水的优化完善

通过介绍平榆高速公路修建中,排水优化完善的过程和所采用的处理方法,分析了处理路基排水问题和处理已有水利管网与路基相交叉时采用的方法,处理问题时应注意的主要事项和关键时间,浅谈了高速公路排水优化完善的方法,为高速公路的排水设计和施工提出几点建议。     

城市轨道交通沿线常规公交线网评价分析

城市轨道交通的建设使得城市公共交通形成典型的层次结构特点,常规公交系统与轨道交通系统的衔接协调性的好坏将直接影响整个公交系统的运营状况。以城市轨道交通为出发点对其沿线的常规公交线网进行评价研究,构建评价指标体系,采用灰关联分析法对公交线网进行综合评价,并将此方法运用到南京市地铁2号线沿线的常规公交线网的优化调整中,取得良好的实践效果。     

��ͨ��Ϣ�ɼ���WSN�ִ��㷨�о�

无线传感网是采集实时交通信息的重要工具.因其节点能量有限,必须设计高能效的分簇路由算法以延长网络周期.本文通过建立一种智能交通中无线传感器网络的应用模型,根据其特点和要求分析LEACH协议的优缺点并提出一种能量负载均衡的分簇算法.该算法对LEACH协议当中的簇首机制进行改进,综合考虑候选节点的剩余能量和簇首节点的分布位置;建立簇间多跳路由机制以避免单跳通信的大能量消耗;创造一种簇重构方法,避免过于频繁的簇重构引起的不必要能量消耗.仿真结果表明,能量均衡算法可有效平衡节点能量消耗分布,延长网络生命周期,可很好的应用于基于WSN的ITS当中.     

Shared ride services in North America: definitions,impacts, and the future of pooling

ABSTRACT

Shared ride services allow riders to share a ride to a common destination. They include ridesharing (carpooling and vanpooling); ridesplitting (a pooled version of ridesourcing/transportation network companies); taxi sharing; and microtransit. In recent years, growth of Internet-enabled wireless technologies, global satellite systems, and cloud computing - coupled with data sharing – are causing people to increase their use of mobile applications to share a ride. Some shared ride services, such as carpooling and vanpooling, can provide transportation, infrastructure, environmental, and social benefits. This paper reviews common shared ride service models, definitions, and summarises existing North American impact studies. Additionally, we explore the convergence of shared mobility; electrification; and automation, including the potential impacts of shared automated vehicle (SAV) systems. While SAV impacts remain uncertain, many practitioners and academic research predict higher efficiency, affordability, and lower greenhouse gas emissions. The impacts of SAVs will likely depend on the number of personally owned automated vehicles; types of sharing (concurrent or sequential); and the future modal split among public transit, shared fleets, and pooled rides. We conclude the paper with recommendations for local governments and public agencies to help in managing the transition to highly automated vehicles and encouraging higher occupancy modes.     

Synchronized Production and Transportation Planning Using Subcontracted Vehicles in a Production-Distribution Network

Abstract

Effective management of interfaces between procurement, supply, production and distribution for higher efficiency in the supply chain is an important issue in global manufacturing, where the synchronization of production and transportation planning represents important savings in operational costs. This paper focuses on the synchronization of production planning and transportation planning in a production distribution network, where transportation is subcontracted to a professional transportation enterprise (PTE) for vehicle-hiring. Dynamic and flexible numbers of vehicles are used to cater for fast changing market demands. Thus, the number of vehicles to be hired is viewed from the planning point of view as an operational decision considered simultaneously with production and transportation planning. A mathematical model – SPTP/MTDS – for synchronized production and transportation planning under multiple times and direct shipping strategy (MTDS) is discussed, and a Lagrange relaxation decomposition-based two layer decision procedure (LRD-TLDP) is developed. By introducing artificial decision variables and Lagrange multipliers, SPTP/MTDS is decomposed into a production decision sub-problem (SPTP-PD), and a distribution decision sub-problem (SPTP-DD). A priority-based assignment heuristic and a partial chain-based genetic algorithm are developed to solve SPTP-PD and SPTP-DD, respectively. An illustration of the application of the model in an electronic appliance manufacturing enterprise in China is presented.     

广西高速公路联网收费管理系统的开发探讨

文章针对广西高速公路联网收费管理系统中的清分结算问题,特别是数据传输和业务逻辑分层处理难题,采用B/S结构模式和基于消息中间件的数据传输技术来进行联网收费管理系统的开发实现。所开发的联网收费管理系统在广西高速公路网管理应用中运行稳定,性能可靠,具体较高的实用价值与技术参考价值。     

Stability and bifurcation in network traffic flow: A Poincaré map approach

Previous studies have shown that, in a diverge-merge network with two intermediate links (the DM network), the kinematic wave model always admits stationary solutions under constant boundary conditions, but periodic oscillations can develop from empty initial conditions. Such contradictory observations suggest that the stationary states be unstable. In this study we develop a systematic approach to investigate the stability property of stationary states in this and other networks within the framework of network kinematic wave theories. Based on the observation that kinematic waves propagate in a circular path when only one of the two intermediate links is congested, we derive a one-dimensional, discrete Poincaré map in the out-flux at a Poincaré section. We then prove that the fixed points of the Poincaré map correspond to stationary flow-rates on the two links. With Lyapunov’s first method, we demonstrate that the Poincaré map can be finite-time stable, asymptotically stable, or unstable. When unstable, the map is found to have periodical points of period two, but no chaotic solutions. We further analyze the bifurcation in the stability of the Poincaré map caused by varying route choice proportions. We apply the Poincaré map approach to analyzing traffic patterns in more general (DM)ⁿ and beltway networks, which are sufficient and necessary structures for network-induced unstable traffic and gridlock, respectively. This study demonstrates that the Poincaré map approach can be efficiently applied to analyze traffic dynamics in any road networks with circular information propagation and provides new insights into unstable traffic dynamics caused by interactions among network bottlenecks.     

高速公路网养护站点布局规划探讨

文章基于高速公路养护站点的职能与类型,分析了高速公路养护站点布局的影响因素,提出了高速公路养护站点布局规划的指导思想、规划原则和约束条件,为形成科学合理的高速公路网养护站点规划布局提供借鉴。     

国土空间规划新形势下的轨道交通规划变革和对策

在国土空间规划新形势下,从轨道交通作为国土空间高品质发展重要支撑要素的角度,以宁波市轨道交通线网规划为例,探讨未来轨道交通规划在规划理念、手段、范围、体系4个方面的变革和对策,认为在规划理念上要遵循全面均衡发展的要求,在规划手段上要遵循"存量规划",思维更多采用"提质增效"措施,在规划范围上要拓展至区域以实现"多网融合...     

一种永磁同步电机声品质主观评价方法研究

对永磁同步电机的稳态信号声品质进行了分析,并以声压级、响度、尖锐度、语音清晰度、波动度、粗糙度和音调度作为评价指标,建立了永磁同步电机声品质评价体系.采用分组成对比较法进行了主观评价,通过Bradley-Terry算法对评价结果进行了优化处理,分别搭建多元线性回归预测模型和MPGA-RBF预测模型,通过预留的检验样本对...