大秦铁路桑干河峡谷工程地质选线

大秦铁路桑干河峡谷山高谷深,地处燕山沉降带中,地质构造非常复杂,不良地质发育,并有煤矿采空区,桑干河峡谷段成为大秦铁路能否顺直的关键.本文介绍了在进行可行性研究时大洋河和桑干河两大方案的选择、初测阶段桑干河峡谷多方案比选以及定测阶段局部方案确定过程中的综合工程地质勘察工作,从而保证了大秦铁路桑干河峡谷段施工的顺利和运营安全.     

跨江河口海湾建桥的主要地质环境问题及对策

本文概要介绍了我国沿海江河口海湾的地质、地貌等环境情况,桥位选址中的主要地质环境问题及采取的相关的措施、方法及建议.     

Estimation of value of travel time reliability

In mode choice decision, travelers consider not only travel time but also reliability of its modes. In this paper, reliability was expressed in terms of standard deviation and maximum delay that were measured based on triangular distribution. In order to estimate value of time and value of reliability, the Multinomial and Nested Logit models were used. The analysis results revealed that reliability is an important factor affecting mode choice decisions. Elasticity is used to estimate the impacts of the different policies and system improvements for water transportation mode. Among these policies, decision maker can assess and select the best alternative by doing the benefit and cost analysis based on a new market share, the value of time, and the value of reliability. Finally, a set of promising policies and system improvement of the water transportation were proposed.     

Tracking individual travel behaviour using mobile phones without information from base stations

Data collection methods that use mobile phones have been developed for tracking, monitoring, and analyzing travel behaviour. Previous methods using a Personal Handy Phone System (PHS) assumed that the location data of base stations were known. This paper shows a positioning method for a mobile object when base station location data are unavailable. Instead of base stations, signal strength vectors (reference vectors) are observed at many places in a target area. Mobile objects also observe a signal strength vector (target vector). A similarity index of reference and target vectors is used to calculate the location of a mobile object. This method tracked the ambulatory behaviour of tourists in an urban setting.     

Simulation studies of information propagation in a self-organizing distributed traffic information system

This paper investigates the feasibility of a self-organizing, completely distributed traffic information system based upon vehicle-to-vehicle communication technologies. Unlike centralized traffic information systems, the proposed system does not need public infrastructure investment as a prerequisite for implementation. Due to the complexity of the proposed system, simulation is selected as the primary approach in the feasibility studies. A simulation framework is built based on an existing microscopic traffic simulation model for the simulation studies. The critical questions for building the proposed market-driven system are examined both from communication requirements and traffic engineering points of view. Traffic information propagation both in freeway and arterial networks via information exchange among IVC-equipped vehicles is tested within the simulation framework. Results on the probability of successful IVC and traffic information propagation distance obtained from the simulation studies are generated and analyzed under incident-free and incident conditions for various roadway formats and parameter combinations. Comparisons between the speed of the incident information wave and the speed of the corresponding traffic shock wave due to the incident are analyzed for different scenarios as the most crucial aspect of the information propagation as a potential foundation for application in such a decentralized traffic information system.     

Valuation of externalities through neo-classical methods by including institutional variables

Externalities are uncompensated influences that are not expressed in a market but that affect the production possibilities or the welfare level of third parties. An example is the noise pollution in airport areas. Although air transport is an important source of economic growth and employment in many countries, the social and environmental problems connected with this sector are rising rapidly. Consequently, airports are becoming a matter of concern to many politicians. On what kind of values should they base their decisions as to further growth or consolidation of the current situation? In this paper we discuss two approaches, one based on mainstream, neo-classical, economics, and one based on institutional approaches, more in particular new institutional economics, which can be seen as a development complementary to the mainstream.     

称重台计算机数据采集系统软件的升级及功能强化与完善

青年基金项目《称重台计算机数据采集系统软件的升级及功能强化与完善》如期完成，本文将原有软件的部分不足和新软件的改进以及增加的功能作一个比较。     

局域网在计量管理中的重要作用

铁路跨越式发展必将带动铁路运输生产、经营管理的巨大变化，也必将促使计量这项技术基础工作发生重大变革。局域网的普及为计量工作的创新发展提供了优质平台。     

加强铸钢配件采购和入厂验收的技术探讨

针对铁路铸钢配件采购和入厂验收存在的问题，提出了加强铸钢配件质量控制的办法，为保证产品质量提供了必要的技术依据。     

加强轨距尺检定器的管理维护确保量传准确可靠

随着轨距尺检定器使用时间的延长。因受外界条件影响，如：温度、湿度、辐射、磨损等，其材质、结构、性能逐渐发生变化，送上级计量检定部门检定时，其计量检测准确度逐渐降低（检定器是合格的）。为保证工务维修用铁路轨距尺计量的单位统一、量传准确。笔者对本公司所使用的是TJGC-1型数显轨距尺检定器的传动系统、调节系统进行了多次认真检查、分析、研究，在TJGC-1型数显轨距尺检定器使用中发现：检定器因使用时间较长，各部件结构松旷、磨损，导致性能不稳定；