压缩铁路货车停留时间的决策分析

在广泛调研的基础上，综合各方意见提出了压缩货车停时的有关技术措施，采用层次分析法进行评定，确定各项措施的重要程度并挑选出经济合理且符合铁路发展趋势的技术措施     

Creator和Vega在虚拟道路交通中的应用

虚拟现实是一种高度逼真地模拟人在现实世界中视、听、动等行为的人机界面技术,已经从面向军事用途扩展到很多领域。文章简单介绍了虚拟现实技术的概念,并在对虚拟现实软件MultiGen Creator和Vega的三维建模技术、LynX图形界面与API函数进行介绍的基础上,将虚拟现实技术应用到道路交通的规划设计中,建立虚拟道路交通系统,并利用Vega声音仿真模块加入了声音效果。经仿真试验,该系统在一般配置的计算机上可以流畅运行,满足实时要求。     

陕西省高速公路路网与道路客运竞争力分析

随着陕西省“米”字型路网构架的不断完善,高速公路路网的运输效率也需要不断提高,以便与一体化的路网发展步调一致。鉴于此,文章对陕西省部分高速公路建成通车后高速公路运输与一般公路运输、铁路运输以及航空运输之间的竞争实力进行了比较,针对目前陕西省高速公路路网的客运运输效率,提出能进一步增强道路客运竞争力的政策建议。     

An analysis of public bus transit performance in Indian cities

Maintaining and enhancing public transit service in Indian cities is important, to meet rapidly growing mass mobility needs, and curb personal motor vehicle activity and its impacts at low cost. Indian cities rely predominantly on buses for public transport, and are likely to continue to do so for years. However, the public bus transit service is inadequate, and unaffordable for the urban poor. The paper explores the factors that contribute to and affect efforts to improve this situation, based on an analysis of the financial and operational performance of the public bus transit service in the four metropolitan centres and four secondary cities during the 1990s. Overall, there were persistent losses, owing to increasing input costs and declining productivity. The losses occurred despite rapidly increasing fares, and ridership declined. The situation, and the ability to address it, is worse in the secondary cities than the metropolitan centres. We suggest a disaggregated approach based on the needs and motivations of different groups in relation to public transit, along with improved operating conditions and policies to internalize costs of personal motor vehicle use, to address the challenge of providing financially viable and affordable public bus transit service.     

基于信用评级体系的治超机制框架研究

通过对道路货物运输信用体系与治超工作相互关系的分析,在借鉴国内外治超有益经验以及相关行业信用体系先进理念的基础上,运用系统工程、信用经济学等方面的知识,采用定量与定性分析相结合的方法,重点就货运企业信用评级指标、流程以及管理模式进行了研究,搭建道路货物运输行业信用综合评定体系框架,并结合实际提出了发挥信用作用的治超新机制和对应措施,为当前的治超工作提供决策参考。     

公交IC卡数据处理的换乘矩阵构造方法研究

针对在城市公交换乘枢纽选址中换乘量调查所面临的困难,利用了公交IC卡的大量信息,并对其进行处理,得出城市公交线路间的换乘量,进而得到城市公交换乘矩阵,并结合长春市公交换乘枢纽规划实例,将该方法应用到城市公交换乘枢纽选址中去.     

Numerical modelling of fish eggs dispersion at the Patos Lagoon estuary — Brazil

The Patos Lagoon estuary is the most important nursery ground for commercially relevant species of fish and crustaceans in the South of Brazil, maintaining fisheries that sustain 3500 fisher families throughout the Rio Grande do Sul State coastline. Around 80% of the interior estuarine area is very shallow (< 2 m), and recruitment of fish eggs and larvae to the inner parts of the Patos Lagoon estuary is directly related to the circulation pattern in the area, which is controlled by local and non-local wind effects and freshwater discharge. The objective of this study is to investigate the processes controlling the transport of estuarine dependent fish eggs between the Atlantic Ocean and the Patos Lagoon estuary.An integrated numerical system based on a bi-dimensional hydrodynamic model and a Lagrangean transport model of passive particles is applied to a selection of scenarios representing the passage of weather fronts over the area. At this stage, fish eggs are represented as buoyant passive particles. Modelling results are compared against field data for the period under investigation (September/October 1999) and historical records. Short term results are analysed in terms of the meteorological conditions (wind direction, intensity and duration) controlling the transport of eggs to the inner parts of the estuary and the extension of their excursion. This experiment is the first attempt to couple biological and physical information to study fish eggs transport, and to enhance the current knowledge about recruitment of important fisheries resources in southern Brazil.     

杭州湾大桥梁上运梁过程仿真分析

对杭州湾大桥非通航孔滩涂区的50 m箱梁上运梁过程进行空间仿真分析。按照实际工况荷载,考虑预应力空间效应,施加等效节点力,并合理考虑支座等细部建模,建立精密的三维实体有限元仿真模型。混凝土的材料特性按现行公路桥梁设计规范取值,考虑最不利计算荷载,支座底部按刚性单元模拟,而与梁相接触层的弹性模量满足梁端回转变形时不出现拉应力,在结构离散时尽可能细分单元网格,由于梁端的应力相对复杂,采用比跨中更密的单元网格。计算承重箱梁整体变形和空间应力分布特性,结果为,由于载荷位置在支座附近,变形相对较小,最大挠度在反拱位移之内。支座截面的最大主拉应力发生在底板上表面侧,超过混凝土的开裂强度,因此,对该区域的混凝土应采取加劲处理,以防止混凝土拉裂;最大主压应力发生在架桥机肢腿处附近,小于混凝土的抗压强度。     

An inverse model for calculation of global volume transport from wind and hydrographic data

The P-vector inverse method has been successfully used to invert the absolute velocity from hydrographic data for the extra-equatorial hemispheres, but not for the equatorial region since it is based on the geostrophic balance. A smooth interpolation scheme across the equator is developed in this study to bring together the two already known solutions (P-vectors) for the extra-equatorial hemispheres. This model contains four major components: (a) the P-vector inverse model to obtain the solutions for the two extra-equatorial hemispheres, (b) the objective method to determine the Ψ-values at individual islands, (c) the Poisson equation-solver to obtain the Π-values over the equatorial region from the volume transport vorticity equation, and (d) the Poisson equation-solver to obtain the Ψ and depth-integrated velocity field (U, V) over the globe from the Poisson Ψ-equation. The Poisson equation-solver is similar to the box model developed by Wunsch. Thus, this method combines the strength from both box and P-vector models. The calculated depth-integrated velocity and Ψ-field agree well with earlier studies.     

Innovative Public Transport Oriented Policies in Seoul

The objective of this paper is to introduce the innovative transport policies of Seoul that have recently been planned and implemented. In this paper, the various transport policies of Seoul are classified and explained according to two important paradoxes that are highlighted by Downs and Thomson, and Edgeworth. These paradoxes describe how to break the vicious circle of car and public transport use by restraining car use and encouraging the use of public transport, and thus indicate how traffic congestion problems might be solved.