Does the pedestrian environment affect the utility of walking? A case of path choice in downtown Boston

There is a lack of consensus as to whether the relationship between the built environment and travel is causal and, if it is, the extent of this causality. This problem is largely caused by inappropriate research designs adopted in many studies. This paper proposes a new method (based on path choice) to investigate the causal effect of the pedestrian environment on the utility of walking. Specifically, the paper examines how the pedestrian environment affects subway commuters’ egress path choice from a station to their workplaces in downtown Boston. The path-based measure is sensitive enough to capture minor differences in the environment experienced by pedestrians. More importantly, path choice is less likely to correlate with job and housing location choices, and therefore largely avoids the self-selection problem. The results suggest that the pedestrian environment can significantly affect a person’s walking experience and the utility of walking along a path.     

既有线路基加固及病害防治措施

文章结合工程实践介绍了几种路基加固及病害防治方法,通过对其作用机理的分析,说明各方法的适用条件,在既有线上实际应用后,效果良好。     

沥青混凝土路面机械化施工机械干扰程度的估计与减小方法

在沥青混凝土路面机械化施工中，合理安排各机械的协调工作对提高路面质量、生产效率和经济效益都有着不可忽视的作用。通过引进机械干扰系数来衡量机械的干扰程度，并由此而得到减小机械干扰的措施，为合理组合、调配机械提供了理论依据。     

对我国城市有轨电车技术发展的思考

简要介绍了城市有轨电车的发展过程及我国城市有轨电车车辆技术现状，阐述了我国现代有轨电车车辆技术发展趋势。     

某大桥主桥拱形连续箱梁施工

某大桥主桥拱形连续箱梁采用满布支架分段浇筑法施工,介绍钢管桩支架施工技术及拱形连续箱梁混凝土施工技术。     

快速启动电控陀螺罗经的仿人智能控制

快速启动陀螺罗经,对提高罗经的工作性能及改善舰船战术性能具有重要意义。本文提出将多模态仿人智能控制应用于陀螺罗经的启动过程。仿真试验表明,该控制算法可有效地缩短陀螺罗经的启动时间。     

大连港成为东北亚航运中心的几点建议

从大连港的优势及不足着手，从加强优势、弥补不足的思路出发，对进一步加强大连港建设。进而加快把大连建设成为东北亚航运中心提出几点建议。     

基于Fuzzy-PID组合智能控制理论的船用锅炉水位仿真研究

锅炉是决定船舶航运安全稳定的重要因素。其蒸汽、压力、温度这些非常重要的控制量与汽包水位有着密切的联系。利用模糊控制理论设计锅炉水位模糊控制系统和传统PID控制器优势互补，并应用MATLAB软件对该控制系统进行验证，仿真结果表明该系统对锅炉水位可实现实时最佳控制。     

A review of the effect of a／W ratio on fracture toughness （Ⅰ）—experimental investigation in EPFM

Many experimental investigations have previously been performed and recently done on different shipbuilding structural steels where the specimens size and crack depth/specimen width (a/W) were varied. A series of interesting results have been gained. It is worthwhile to have a review on the effect of a/W ratio on fracture toughness, and further theoretical analysis is necessary. In this paper, experimental work in elasticplastic fracture mechanics (EPFM) was discussed. Tests had been carried out on 10 kinds of strength steels. Results showed that J _i and δ₁ values increased with decreasing a/W when a/W<0.3 for three-point bend specimens and that shallow crack specimens which have less constrained flow field give markedly higher values of toughness than deeply notched specimens. However, for a/W>0.3, the toughness was found to be independent of a/W. Slip line field analysis shows that for shallow cracks, the hydrostatic stress is lower than that from standard deeply cracked bend specimen which develops a high level of crack tip constraint, provides a lower bound estimate of toughness, and will ensure an unduly conservative approach when applied to structure defects especially if initiation values of COD/J-integral are used.     

港口在推动建立现代国际物流中心中的战略意义

在分析了不同阶段物流及港口发展的关系表征和港口推动现代物流的优势之后,从四个方面阐述了建立物流中心的战略意义。