Estimation of extreme significant wave heights and the associated uncertainties: A case study using NORA10 hindcast data for the Barents Sea

The reliability of an offshore structure is dependent on its response to the extreme wave climate; therefore, an adequate knowledge of the wave climate at a location is a prerequisite during design as well as in marine operations. This study aims to contribute to the knowledge of the extreme wave climate in the Norwegian Sector of the Barents Sea, using wave hindcast datasets from the Norwegian Reanalysis 10 km (NORA10) database for four locations.We have considered three commonly used methods for the estimation of extreme wave heights, that is, the initial distribution method, the peak over threshold method, and the annual maxima method. The parametric bootstrap concept is considered in the estimation of the epistemic uncertainty related to sample size. The estimated 100-year significant wave heights obtained from the three methods differ, and the degree of variability in the estimates varies, depending on the dataset. The epistemic uncertainty due to sample size is wider when considering the annual maxima method.The estimates obtained from the three methods show the importance of considering different methods and their associated uncertainties when estimating extreme wave values for design. While it is difficult to single out the best method among the three, the estimated values give knowledge of the possible range of the extreme significant wave heights at the locations. Generally, the datasets considered in this study suggest that the wave climate is less harsh further north compared to the southern region of the Barents Sea. The datasets do not suggest any temporal trends in the historical significant wave heights at any of the locations.     

乾元公司铁路专用线场站模式探讨

目前,传统的铁路专用线建设模式是铁路专用线自接轨站接轨,通过区间正线引入厂区的建设模式,这种模式的区间正线受地形条件、厂区位置和沿线规划影响较大,这些影响将不可避免地导致铁路专用线建设工程投资的增加,如能根据运输性质考虑缩短区间正线长度,在接轨站旁边设装车作业站,将大大减少专用线工程投资.以乾元公司铁路专用线建设模式为例来研究铁路专用线场站模式,就如何在接轨站旁边设装车作业站,实现接轨站设备与铁路专用线共用进行探讨.     

A proposed vision and vehicle-to-infrastructure communication-based vehicle positioning approach

It is essential to obtain accurate location of vehicles for new applications of Intelligent Transportation Systems. To remedy the defects of present Global Positioning System and vehicle-to-infrastructure (V-I) positioning technology, a new positioning approach based on vision and V-I communication is proposed. This approach aims at lane-level positioning with lower cost than conventional ones. In this approach, the position of the vehicle is represented by its lateral position (the lane number) and longitudinal position (the distance from entrance of the road) in a course coordinate system along the road; the specific lane the vehicle is occupying (the lane number) can be judged using the information of lane lines detected by vision systems; then the distance to the vehicle is obtained by a Road Side Unit (RSU) during the V-I communication; and the longitudinal position is calculated. The error of the approach on typical operating conditions is analyzed, indicating that the new approach can achieve the accuracy of less than 0.31 m for straight road and 0.58 m for typical arc road with ultra-wideband communication and ranging technologies and rational arrangement of RSUs. The feasibility of this approach is presented.     

浅析影响路基压实的施工因素及其处理措施

分析了目前路基压实中存在的问题,并提出了相应的控制措施.     

客运站到发线运用优化研究

为了合理编制客运站到发线运用计划,作者确定了到发线均衡性评价标准,建立了既满足到发线固定使用方案,又达到均衡使用到发线的多目标二次0-1规划模型;并以德州东站为实例,利用LINGO软件进行了求解与验证。     

基于参数化船型的阻力优化研究

船型几何模型的参数化表达,是船型多学科设计优化的基础。其作用是为各学科分析和优化提供一个统一的几何模型,并根据各学科分析结果自动修改调整船体型线。文中尝试使用Friendship进行船体完全参数化建模,并使用该软件中的feature编程功能编程实现shipflow型值数据的提取;通过改变一系列重要的船型参数实现变换船型几何模型,以获得满足性能需求的船型。最后利用该软件的优化框架,采用切线搜索法 (Tangent Search, TSearch) 完成1300TEU集装箱船的兴波阻力优化,优化球首和前体船体曲面。结果表明,该参数化方法在改进船型水动力性能方面有很好的效果。     

城轨列车故障救援与停车线设计

通过对广州地铁的列车故障救援分析,总结城轨列车故障救援的组织原则,从列车故障救援组织的角度,提出停车线的设计应考虑列车故障救援,并对停车线设计的原则和《地铁设计规范》的完善进行探讨。     

"天鲸"号大型自航绞吸式挖泥船

论文介绍了国内的第一艘自航绞吸式挖泥船"天鲸"号的主要要素、总布置概况、型线、柔性钢桩台车系统、输泥系统和推进装置,定性地探讨了它的艏部型线设计和灵活的输泥系统配置,对它的挖掘岩石能力作了计算.文中提出了法规对驾驶台翼桥宽度的要求,可供有关部门参考和探讨.     

中大型客滚船的线型与推进系统研究

本文介绍了当今世界上典型的中大型客滚渡船传统的线型设计方法和推进系统,以及近年来针对大型客滚渡船研发的新推进理念和方法。详细介绍这些新的推进理念,并将其与传统的方式进行比较,对将来的实际应用提出了建议。     

新建隧道爆破施工振动影响研究

文章以新建库鲁塔格隧道爆破施工为例,通过进行爆破振动测试,分析爆破施工过程中既有隧道的爆破振动速度与微应变之间的相互关系,研究新建隧道爆破施工对临近既有隧道的影响。