军用载货汽车轮胎压力温度监测装置研究

对轮胎压力温度监测装置在军用载货汽车上应用的必要性进行了分析,对轮胎压力温度监测装置的总体技术方案进行了研究,该系统的应用对提高军用载货汽车机动过程的安全性具有一定的意义。     

基于AI原理的牵引供电远动系统线路带电推导算法

结合ＡＩ原理，采用启发式深度优先算法实现了牵引供电远动系统线路带电推导，对该算法进行了理论分析，并给出了实现该算法的控制策略及软件框架。     

ADSL接入网与上海地铁通信网建设

介绍了复双绞线并采用ＡＤＳＬ技术的接入网基本原理与接口方式，并根据上海地铁通信系统的要求，提出了采和双绞线作为物理介质的接入网人步行了铁通信系统接入网的过渡方案，并对其实现提出了具体的方案。     

Transportation agencies experiences with decision support systems for airport ground access planning

This article reports on a field investigation into the ways that transportation agencies use quantitative and qualitative information for making strategic decisions regarding airport ground access. The study analyzes the value of this information for planning airport ground access improvements at seven major international airport sites.The major finding of the research is that quantitative modeling for strategic decision support is very difficult, costly and time consuming. Modelers are confident that the models are accurate and reliable but executives generally lack confidence in the results. Transportation officials believe that the information supplied is flawed by a number of defects that minimize its value for strategic decision makers. The information defects described in this article provide an analysis of the structural difficulty of using quantitative modeling for transportation problems of strategic importance. To date, qualitative information is not frequently used, but some transportation agencies are considering its application to designing transportation services. Although this study is limited to airport ground access, the authors feel that this evidence, in conjunction with the evidence from other studies in the transportation area, dictates a need for wariness in the development of decision support systems for transportation planners. Developers of decision support systems for transportation planners must be aware of modeling costs and defects and consider how to improve the timeliness, relevance and credibility of information quantitative models provide transportation executives. Fundamentally it is important to recognize that decision makers tend, either singularly or in concert with other individuals or groups, to be the champions of a long-term vision for the community. When modeling produces inconsistent or wide ranging results that contradict their position, decision makers may not only discard modeling activities, but lose confidence in the models altogether. As a consequence, transportation planners are faced with the challenge of how to improve quantitative modeling. The most reliable and effective means for improvement is incorporation of qualitative techniques which provide greater understanding of customer perceptions and human behavior.     

客运专线无砟轨道路基面防水设计方案

综合路基面防水设计的国内外研究及应用现状,得出了热拌沥青混合料是路基面防水材料的首选.通过分析路基面防水层的功能要求,并参照公路、建筑、水工等其他工程领域的沥青混合料防水性能最新进展,归纳和分析了我国客运专线无砟轨道路基面防水层混合料特性及指标设计方案.     

基于VRML的虚拟现实地理信息系统的设计与实现

虚拟现实地理信息系统是将地理信息系统(GIS)技术和虚拟现实(VR)技术相结合的新技术,文中首先提出了一种通过松散模型构建VRGIS系统的方法,然后对空间数据的组织和管理、空间数据引擎的选择、空间数据和属性数据的挂接等关键问题进行了阐述,最后给出了基于VRML的虚拟现实地理信息系统的开发实例.     

Privatization of urban transit: The Los Angeles jitney experience

This paper reports on a recent attempt to provide private transit in the form of jitney service in downtown Los Angeles. It describes the process undertaken to initiate jitney service and the resultant organization's structure and operation. A survey of jitney passengers provided information on the users and their tripmaking characteristics. A group of loyal jitney riders emerged who patronized the service because of its lower travel times and more personalized atmosphere. This group formed the core of frequent users. The Los Angeles experience is analyzed in terms of the economic feasibility of jitney service and the impact on the financial status of public transit. The public transit agency experienced a slight negative financial impact as a result of the jitney service. Ridership during peak hours declined somewhat but the jitney service was not frequent enough to carry sufficient passengers to allow the transit agency to cut costly peak hour service. This analysis shows that the jitney service ultimately was not an economically successful operation. The factors which would have increased the likelihood of success were increased frequency of service and higher fares, which would have been sustainable if not for unexpected developments in public transit financing. A labor pool willing to work for low wages, high transit use in the central city, relatively high transit fares and the availability of inexpensive vehicles appear to be prerequisites to a successful urban jitney operation.     

Analysis of the capabilities of a two-stage turbocharging system to fulfil the US2007 anti-pollution directive for heavy duty diesel engines

This article presents a two-stage turbocharged heavy-duty diesel (HDD) engine designed to fulfil the US2007 anti-pollution directive. This directive imposes very restrictive limits on the NOx and particle emissions of HDD engines. In this work, the possibility of combining particle traps in the exhaust line to reduce soot emissions with very high EGR rates to reduce NOx emissions is considered. This new generation engine implements two-stage turbocharging in order to improve the bsfc when the engine is working on steady conditions as well as to optimize the engine transient response. After carrying out the tests, the results were analyzed and the engine settings were adjusted to maximise its behaviour and minimise pollutant emissions. NOx and soot emission peaks were also analyzed at engine transient conditions in order to keep them under certain levels, and thus maintain the overall pollutant emissions to a level that is as low as possible. In summary, a double-stage turbocharging configuration can greatly improve engine driveability (between 23% and 36% depending on engine speed), while reducing NOx emissions during transient evolution without increasing opacity peaks beyond the stated limits.     

C++编程计算像片外方位元素及多个用途

对于框幅式摄影机获得的影像,用C 程序实现单像空间后方交会,计算像片的外方位元素,这是最基本的应用.同时,又是双像解析摄影测量的"空间后交-前交"解法、光束法双像解析摄影测量、光束法区域网平差的核心部分.对于其他遥感传感器获得的影像解求其外方位元素,该程序模块也具有参考价值.由于C 的特点,该程序可用于嵌入和拓展.     

考虑楼板变形时框支剪力墙结构的框支层合理设计研究

将框支剪力墙结构沿竖向划分成为转换层上部剪力墙结构和转换层下部框架-剪力墙结构。对各部分结构假定质量刚度沿高度均匀分布,将楼板看成水平放置的深梁,并假定以剪切变形为主。根据平衡条件,列出微分方程组。采用相应的数学程序求解,得到结构水平侧移及各构件内力。通过对内力和侧移的双重控制,进行框支层的合理设计。