混合动力汽车及其动力匹配策略

为应对石油危机及大气污染,混合动力汽车（HEV）成为汽车行业的研究重点。从动力来源、动力混合程度及动力系统布置及组合方式3方面对HEV进行分类,介绍了串联式、并联式及混联式HEV的结构形式及优缺点。将当前的控制策略归为基于规则的控制策略和基于系统优化的控制策略,指出当前的控制策略无法自适应复杂路况的需求,不够智能,不利于整车性能提高。提出兼顾整车性能的多智能体集成控制是未来HEV控制策略的研究重点。     

双馈风力发电系统低电压穿越控制的分析研究

文章对国内外的风力发电低电压穿越的现状进行了综述,并对主要的低电压穿越方案进行了分析研究,具有一定的参考意义。     

大跨度桥梁挂篮施工技术研究

文章对挂篮施工技术进行了概述,并在此基础上分析了其施工原理,最后结合工程实例探讨了大跨度桥梁挂篮施工技术．为施工实践提供借鉴。     

BRT and BHLS around the world: Explosive growth,large positive impacts and many issues outstanding

A survey of Bus Rapid Transit BRT and Bus of High Level of Service BHLS around the world indicates that there are about 120 cities with bus corridors, with 99 of the cities entering into the list in the last 12 years. The existing bus corridors comprise about 280 corridors, 4300 km, 6700 stations and use 30,000 buses, serving about 28 million passengers per day. In 2010–2011, 19 cities completed new systems − 16 in the developing world – and seven cities expanded their current systems. By late 2011, about 49 new cities were building systems, 16 cities were expanding their corridors, and 31 cities were in initial planning. This impressive growth may be attributed in part to the successes of Curitiba, Bogotá, México City, Istanbul, Ahmedabad and Guangzhou. These cities show low cost, rapid implementation and high performance BRTs, with significant positive externalities. Interesting trends are emerging, such as the implementation of citywide integrated bus systems, improved processes for private participation in operations, increased funding from national governments, and growth of bus manufacturers and technology providers. Despite the growth, there are some outstanding issues: BRT and BHLS do not have a single meaning and image and are often regarded as a “second best” as compared to rail alternatives. In addition several systems in the developing world suffer problems resulting from poor planning, implementation and operation, due to financial, institutional and regulatory constraints. The BRT and BHLS Industry are in their “infancy” and there is need for consolidation and concerted effort.     

The economics of railway safety

This paper reviews the statistics and economics of railway safety in Great Britain, the European Union and the United States, together with some results for Finland and Japan. In these countries railway safety has improved over recent decades. That finding applies both to train accidents and to personal accidents such as persons struck by trains. Fatal train collisions and derailments command most attention even though they are infrequent and account for only a small minority of railway fatalities. Great Britain, the EU and the USA formally espouse conventional cost benefit analysis for the appraisal of railway safety measures, using the same valuations for the prevention of casualties as are used in road safety appraisal. However there are often strong institutional, legal and political pressures towards adopting railway safety measures with safety benefit: cost ratios well below 1. The best-documented examples of this are automatic train protection systems, which are discussed in the paper. Apart from trespassers, the largest group of railway fatalities occur at level crossings, which the paper also discusses. Level crossing safety measures would seem to be an appropriate subject for cost benefit analysis, but there are few case-studies in the literature. Over the last few decades, the railways in many countries have been privatised or deregulated with the aim of improving their economic performance. Such changes have the potential to affect safety. The paper reviews evidence of the effects on safety of railway restructuring in Great Britain, Japan and the United State, and finds no evidence that safety deteriorated.     

船舶燃气轮机装置分布式集成仿真平台设计

针对船舶燃气轮机装置分布式集成仿真的功能,设计了包括应用层、支撑层、通讯层和设备层在内的分布式集成仿真平台体系层次。选择 MATLAB/SIMULINK环境开发应用层和支撑层,选择HLA协议和RTI软件实现通讯层。最终形成了由平台运行管理器、分布式仿真包、模块化模型库、分布式仿真接口以及RTI软件组成的“服务器/运算节点”式的平台运行框架。通过某型双轴燃气轮机在机械推进工作方式下的分布式集成仿真实验,初步验证了平台体系框架的合理性和有效性。     

A structural equation model of activity participation and travel behavior using longitudinal data

Abstract

This paper presents a dynamic structural equation model (SEM) that explicitly addresses complicated causal relationships among socio-demographics, activity participation, and travel behavior. The model assumes that activity participation and travel patterns in the current year are affected by those in previous years. Using the longitudinal dataset collected from Puget sound transportation panel ‘wave 3’ and ‘wave 4,’ these assumptions are tested with suggested SEMs. Within each wave, the model is structured to have a three-level causal relationship that describes interactions among endogenous variables under time-budget constraints. The resulting coefficients representing the activity durations indicate that people tend to allocate their time according to the importance and the obligation of the activity level. Results from the dynamic SEM confirm the fact that people's current activity and travel behavior do have effects on those in the future. The resulting model also shows that activity participation and travel behavior in ‘wave 3’ are closely related to those in ‘wave 4.’ These explicit explanations of relationships among variables could provide important perspectives in the activity-based approach which becomes recognized as a better analytical tool for the transportation planning and policy making process.     

特长隧道供配电系统方案设计

从隧道日常管理与运营维护的实际情况出发,本着＂安全、可靠、经济、环保＂的原则进行供电方案设计。结合某工程的负荷分布情况等,提出了横洞变式集中供电与地埋变式分散供电两种方案,经分析研究推荐采用横洞变式集中供电方案。     

基于多特征的纹理特征提取方法研究与应用

纹理是图像的1种重要视觉特征,常用于识别和区分图像。纹理特征的提取则是其应用需首先解决的问题。通过总结分析目前较为常用的纹理特征提取方法,基于灰度共生矩阵(GLCM )算法、局部二值模式(LBP)算法和小波变换(DWT )算法的特点,提出基于多特征的纹理特征提取算法,即将各算法提取的特征进行融合。融合中使用权重对参数进行配置。论文设计了1种图像检索实验,通过图像检索实验比较了各算法提取的特征对纹理的描述能力。结果表明,对于Co rel图像库,笔者提出的多特征的纹理特征提取算法检索的平均查准率相对于GLCM 算法提高了20%,相对于LBP算法提高了9%,相对于DWT算法提高了10%,相对于徐少平等人提出的特征融合方法提高了15%。证实了文中所提出的算法能够兼顾各算法的优点,并具有较好的旋转不变性和尺度不变性。其不足之处是需要同时提取GLCM 算法,LBP算法,DWT 算法下的纹理特征,计算所需时间是后3种算法时间之和,使算法的实用性受到了一定的限制。      

液力机械自动变速器动力性换挡点算法研究

为得到发动机与液力变矩器共同工作点及动力性换挡点精确计算结果.对发动机净转矩外特性曲线采用三次样条插值,并构造了求解共同工作点及动力性换挡点的求值函数.分别采用改进二分法和牛顿下山法来求解构造函数零值.通过实例计算和分析表明,这2种方法运行速度快、精度高,求得的动力性换挡特性提高了液力传动车辆的匹配效率.