提高城市平面交叉口通行能力的对策分析

在城市交通中,平面交叉口已成为瓶颈,因此解决城市交通拥堵的关键,在于提高城市平面交叉口的通行能力、减少车辆在交叉口的延误时间。利用交通工程设施控制,可以以较少的资金投入,利用现有的交叉口进行改造,做到渠化交通,使机动车与非机动车分离行驶,在同一交叉口分配不同路权,从而达到控制混合交通、减少冲突点、提高交叉口通行能力、减少车辆延误的目的。     

基于模型预测轮廓控制的自动驾驶车辆路径跟踪控制

为了实现无人驾驶汽车的路径跟踪和避障功能,基于模型预测轮廓控制提出一种路径跟踪控制策略。首先将二自由度单轨车辆模型和Pacejka轮胎模型结合在一起搭建整车模型,遵循模型预测的思路将路径规划和跟踪问题结合为一个非线性优化问题,利用线性化得到线性时变模型,在每个采样时间内以凸二次规划的形式建立非线性优化问题的局部逼近。其次,为了使车辆在跟踪路径的时候维持稳定,结合车辆稳定包络线,施加横向稳定性约束,并通过施加车道线边界约束,实现自动驾驶车辆的避障功能。最后将Matlab/Simulink和Carsim结合进行联合仿真。仿真结果表明,所设计的控制器在较宽路面能自主规划出一条最短路径,实现了跟踪和避障功能,同时维持了车辆在行驶中的稳定性和安全性,在赛道竞速下具有较明显的优势。研究结果可为结构化道路下的汽车自动驾驶提供技术参考,具有一定的应用价值。     

“我们都很满意G-BOS系统”

在2011年北京客车展"全国道路客运企业高新技术应用论坛"上,多位行业专家针对车辆管理系统,也就是目前客运行业的关键词——"车联网"进行探讨。"车辆管理系统,为巴士与客车运营提供有效管理的简单工具。"重庆大学教授王健从4个方面评价说,G-BOS系统在发动机及车辆技术管理方面,有效节省油料开销、降低营运成本、了解车辆使用状况、油压监测、冷却系统监测等;驾驶员管理方面,提高行车安全、减少事故率、出勤管理、奖惩制度的建立及执行、提高车队效率、优化驾车行为;车辆运行管理方面,车辆使用负荷管理、追踪车辆行驶路径、与车辆保持联系、防盗功能、路线旅     

汽车燃料经济性计算方法研究

汽车行驶时的燃料经济性以百公里油耗为其评价指标,而正常行驶的车辆包括怠速、加速、等速、减速和换档五种行驶状态,本文分别给出在这五种行驶状况下的燃料经济性和计算方法。     

能吸收雨水的防滑路面

目前的高速公路路面容易积水,车辆高速行驶时,轮胎和路面间形成的水膜会使轮胎打滑,造成车辆失控,导致车祸。最近日本道路公园正在全国高速公路上推行“高功能铺设”的新施工法,即在铺设沥青路面时使沥青发泡形成空隙。这种保留空隙的路面容易吸收雨水,并通过路面和混凝土路基间隙将雨水排出,从而抑制了轮胎打滑,提高了对车辆的控制能力,减少车祸。其次,高速行驶的车辆在积水的路面上溅起的水花会形成水雾,使其后行驶的车辆驾驶员的视线模糊。夜间行驶时积水的路面容易使车灯光产生反射,扰乱驾驶员视线。新施工方法可减少上述不…     

车停何处？——汽车社会的发展过程与停车管理政策

停车或言静态交通，它与动态交通一样．是城市交通建设的重要组成部分．有了车的停驻．才能有车的行驶。因此．停车政策与道路交通政策同样重要。 停车政策所涵盖的内容可用以下的思路进行分析：汽车的行驶一定有它的出发点和目的地．汽车在出发地和目的地必然要停车。山发地停车场．一般还是汽车不使用时的保管地。而在目的地停车一般可以归结为办理公、私事务、装卸货物、换乘车辆时的临时停车。时间有长有短。 不当停车会给汽车社会造成许多不良影响，举日本一九九三年实例来说明：首先，路边停车可能造成交通事故。日本在一九九三年全国…     

TOYOTA油电混合动力系统

油电混合动力车,拥有发动机和电动机双动力的跨时代技术。普通的汽车都是单靠发动机驱动车辆。但车辆在低速行驶时,发动机的油耗并不理想。     

客运信息化程度在加深

客运企业借助3G系统对运营车辆进行管理调度似乎已经不是什么新鲜事儿了,得益于这一技术,客运公司实现了车辆实时位置的监控、车辆行驶状况的监控以及车辆行驶路线的监控,并可以通过发送短信的形式对车辆进行及时调配。这一方面促进了营运车辆的规范化运营,提高了车辆的安全性;另一方面也让客运公司具有更好的车辆调度能力,使企业的运营成本大大降低。     

高速公路养护施工安全管理措施分析

高速公路上车辆行驶速度比较快,因此,高速公路交通事故发生的后果往往也很严重,而某种意义上来说,高速公路建设施工时的施工质量最终决定了高速公路建成之后的质量安全性,近年来,我国在高速公路建设过程中特别强调要做好其养护施工安全管理工作,目的就是为了降低高速公路事故频发的几率,保证行驶车辆的使用安全性。论文分析了高速公路养护...     

基于物联网技术的智能交通系统中车辆通信网络研究

随着城市现代化的快速发展,城市交通拥堵问题无疑是现代城市管理的一大难题。智能交通与物联网的融合将是今后智能交通的发展趋势,随着智能交通系统的发展,车辆通信网络已经成为该领域的热门网络通信技术,有着广泛的发展前景,路由协议是车辆通信网络中关键的环节之一。文章建立了智能交通系统中车辆通信网络的数据通信场景,使用OPNET Modeler软件进行建模和仿真,对车辆通信网络的总体性能进行了评估。     

质量体系与HSE管理体系一体化初探

从分析ＩＳＯ９００标准与ＨＳＥ管理标准的相同点和不同点入手,从管理学的角度探讨了质量体系与ＨＳＥ管理体系相结合的可能性与必要性,探讨了企业实施两个体系一体化的措施。指出,建立一个能同时满足了ＩＳＯ９０００标准要求和ＨＳＥ管理标准要求的综合体系,可以明显地提高企业管理效益、降低体系运行费用。     

Comparing FTTH access networks based on P2P and PMP fibre topologies

There is an ongoing discussion in the market which Next Generation Access (NGA) architecture best suits future needs and which investment and cost differences exist. The discussion can be subsumed as P2P vs. GPON, which is somewhat misleading as this article reveals. The discussion is driven by the fact that the high capital cost and the long asset life time of fibre mean that the technology choices made today will dominate the opportunities for telecommunication business of all market players, incumbents, competitors, content providers and business and residential users for many years in the future.The paper analyzes the cost and other differences between Fibre-to-the-Home (FTTH) access network architectures and their related different wholesale approaches by using the well-known and understood steady state approach applied in other NGA analyses in the past. In addition to the steady state analysis a dynamic cost evaluation is included taking into account the different investment behaviour of the FTTH architectures over time. The results describe investment and cost differences between architectures, incumbents and wholesale based competitive operators. The analysis has been performed for different geotypes (clusters) of decreasing population density in a representative European settlement structure.     

钻井液滤液中氯离子含量的不确定度评定

依据测量不确定度的评价原则,从方法概述、确定不确定度的来源、建立数学模型、计算相对标准不确定度分量、合成相对标准不确定度、扩展不确定度等入手,通过实例详细阐述了钻井液滤液中氯离子含量测定的不确定度评定方法。     

施工企业工程项目部的建设浅论

工程项目的一次性决定了工程项目部的一次性，而工程项目成本中心与企业利润中心地位又辱致工程项目部的临时性，在工程项目实践过程中，项目经理部的一次性在实现其功能的过程中可能会产生很多局限和负面影响，故项目部应具有相对的稳定性，在此基础上，本对工程项目部建设实践进行了初步总结并提出了建议。     

Selection of standards for digital television: The battle for Latin America

This paper analyses the implementation of Terrestrial Digital Technology (TDT) standards in Latin America. The analysis suggests that while some governments have chosen the standard attending to their industrial objectives, others have been influenced by the relevance of network externalities and scale economies and by the political and commercial relationship with their neighbours. The discussion about the technical characteristics of the systems was only relevant in the first years of the process, when the leading countries of the region had still not made their selection. Brazil decided to create its own version of the Japanese ISDB standard in 2006, and in the following years it has persuaded a significant part of the continent to choose it. Another block of countries has adopted the US ATSC standard. The most prominent case is that of Mexico, which has a preferential access to the US market. Only three countries have chosen the European DVB standard, the most widely used standard in the world. Colombia has tried to lead its introduction in the continent, but the results so far have been meagre.     

参加ISO/TC 67第21届年会报告

介绍了ISO／TC67第21届年会组织概况及会议重要决议，对TC67石油工业国际标准化的发展进步，标准制定数量和速度，各成员国采标方法和经验，以及相关国际组织工作动态等作了集中评述，在对比分析的基础上就ISO／TC67中国国内归口管理，石油工业标准化（SY）工作与国际接轨，标准化与电子化，管材标准与国际组织同期审议等提出了建议。     

Migration to 3G wireless broadband internet and real options: The case of an operator in India

The paper focuses on third generation wireless technologies and on alternative technologies for wireless local area networks. The authors present the evolutionary migration path from second to third generation systems. Technological, economic and behavioral factors related to decision-making towards the migration are proposed. As an example, the paper studies the case of the national incumbent operator of India. It analyzes qualitatively the migration problem from the perspective of the operator, the equipment manufacturer and the users. For the quantitative analysis, real options are used to value the investment decisions. The analysis suggests that the initial (sunk) investment cost, the average revenue per user, the growth of the subscriber base and the volatility of the markets are the key factors in the investment process.     

具有异质性扩散率的传染病模型分析

为了刻画大尺度空间范围内的个体移动对疾病传播的影响,主要研究了异质集合种群网络的传染病传播过程。由于城市之间存在规模以及交通发达程度等方面的异质性,扩散率也存在一定的异质性。以城市作为节点,建立了具有异质性扩散率的传染病动力学模型,更加准确地刻画了网络结构以及人们的出行对疾病传播的影响。通过对系统进行定性及稳定性分析,发现系统存在一个无病平衡点,并得到了无病平衡点不稳定的阈值条件。当达到疾病爆发的阈值条件时,系统存在唯一的地方病平衡点,并且地方病平衡点是局部渐近稳定的。通过数值模拟验证了理论的正确性。研究表明,增大扩散率能加快疾病的流行速度,因此,通过有效控制大城市的人口出行率可以在一定程度上控制疾病的爆发。     

Proposals for a digital industrial policy for Europe

A digital industrial policy should take into account the new opportunities for industrial policy arising from digitalisation for tackling the sluggish economic growth performance in the Europe. The structural problems and potential market failures related to the adoption of digital technologies are identified. Apart from incentives to invest into digital infrastructure, the policy measures should strengthen the intangible asset base along the value added chain of the digital economy, fostering the related R&D activities, along with the skills of researchers and of workers. Public and private sector financing, combined through financial instruments, should focus on furthering entrepreneurship and implementation of innovative business plans.     

Trends in feed, livestock production, and rangelands during the transition period in three Central Asian countries

After the breakup of the Soviet Union, the republics of Central Asia began to restructure their agricultural sectors to achieve food security and to adjust to the requirements of a market economy. Although they encountered many common challenges, their agricultural policies differed significantly. For this reason, it is important to see the results of these policies and to learn lessons from them. This paper discusses the role of and the challenges facing rangelands and livestock production systems in achieving food security among the pastoral communities of Central Asia. It analyzes the trends in livestock development during the economic transition in Kazakhstan, the Kyrgyz Republic, and Uzbekistan, and derives policy directions for the sustainable use of rangelands and for the growth of the livestock sector in Central Asia.