广州地铁1号线的线路专业委外维修模式

随着广州地铁线网的快速发展,现有的维修模式不能满足地铁的超常规发展,探索新的维修模式成为地铁运营的一个重要课题.以广州地铁线路专业现有的维修模式为基础,从技术、经济、维修质量的控制、风险管理控制、生产组织、项目管理等方面进行委外维修模式的论述,阐明委外维修的目的和内容,并进行可行性分析.     

北京地铁14号线高家园站-望京站区间单洞双线盾构临近穿越群桩的响应与防护

为减小盾构隧道施工对邻近群桩基础的影响,对10 m内径盾构穿越的机场快轨群桩响应进行数值模拟,分析盾构法隧道施工引起的群桩变形及内力变化情况。结果表明,开挖后桩身发生弯曲变形,桩身内力发生明显变化,前桩具有隔断作用,隧道施工对群桩中后桩的影响较小。群桩邻近盾构时采用复合锚杆桩作为隔断桩,复合锚杆桩加固桩侧土体的同时,可采用多排组合形成较大隔离刚度,套管施工可有效控制施工期间的环境影响。     

天津大沽河5万吨级航道工程泥沙数值模拟研究

天津临港工业区根据需要拟在海河口南治导线北侧通过大沽河开挖一条5万吨级通海航道.通过建立潮流、波浪、泥沙数学模型,利用现场水文、泥沙实测资料对航道开挖后在海洋动力条件作用下的泥沙淤积进行了计算预报,为工程的建设与设计提供了科学的依据.     

海上舰艇对空作战仿真研究

通过分析海上舰艇编队对空作战环境和作战过程,提出面向对象的仿真模型开发与设计,采用HLA技术,设计了仿真系统,给出海上舰艇编队对空作战流程的仿真框图.     

福建沿海航标设置管理问题探讨

讨论分析福建沿海航标设置管理存在的问题,对如何建立协调有序、经济便捷、安全可靠的航标助航体系,加强航标设置管理提出了对策建议。     

从“油轮单壳改双壳”到“油轮改散货轮”

本文主要阐述了油轮改散货船在流程管理、变形控制、安全管理、质量管理、周期控制等方面的难点及防控要点。     

连续悬索桥受横桥向船撞力的分析

应用平面有限元计算程序代替空间有限元计算程序，解决了连续悬索桥受横船撞力的分析问题，通过对具体算例的分析，得到了有益的启示。     

大学英语口语测试及评估的几点基本考虑

通过以大学英语考试的口语测试和2003年研究生入学考试中的英语口语测试的效果为例，从其效度和信度方面，分析面对面的口语测试和非面对面的口语测试的优缺点，得出进行能客观反映学生口语水平的高质量的口语测试是可能的。     

航行中船舶纵向齿轮机构机械效率的实验验证

船舶在波浪中航行时,船舶的总体弯曲变形会使沿船体纵向布置齿轮机构的轴承座中心距产生缩减,从而可能使齿轮机构处于双面啮合工作状态[1]。文献[2]推导了在该双面啮合工作状态时沿船体纵向布置齿轮机构机械效率的理论计算公式。本文着重以一种简单的实验测定方法对该理论计算公式进行验证。实验测定表明,理论计算结果与实验测定值接近,理论计算公式切合实际。     

Not bored yet - Revisiting respondent fatigue in stated choice experiments

Stated choice surveys are used extensively in the study of choice behaviour across many different areas of research, notably in transport. One of their main characteristics in comparison with most types of revealed preference (RP) surveys is the ability to capture behaviour by the same respondent under varying choice scenarios. While this ability to capture multiple choices is generally seen as an advantage, there is a certain amount of unease about survey length. The precise definition about what constitutes a large number of choice tasks however varies across disciplines, and it is not uncommon to see surveys with up to twenty tasks per respondent in some areas. The argument against this practice has always been one of reducing respondent engagement, which could be interpreted as a result of fatigue or boredom, with frequent reference to the findings of Bradley and Daly (1994) who showed a significant drop in utility scale, i.e. an increase in error, as a respondent moved from one choice experiment to the next, an effect they related to respondent fatigue. While the work by Bradley and Daly has become a standard reference in this context, it should be recognised that not only was the fatigue part of the work based on a single dataset, but the state-of-the-art and the state-of-practice in stated choice survey design and implementation has moved on significantly since their study. In this paper, we review other literature and present a more comprehensive study investigating evidence of respondent fatigue across a larger number of different surveys. Using a comprehensive testing framework employing both Logit and mixed Logit structures, we provide strong evidence that the concerns about fatigue in the literature are possibly overstated, with no clear decreasing trend in scale across choice tasks in any of our studies. For the data sets tested, we find that accommodating any scale heterogeneity has little or no impact on substantive model results, that the role of constants generally decreases as the survey progresses, and that there is evidence of significant attribute level (as opposed to scale) heterogeneity across choice tasks.