A porous cell method for the simulation of fluid-solid interactions

There are many ways of describing a solid,porous or fluid region of the computational domain when solving the Navier-Stokes equations(NSE)for flow motions.Amongst these the porous cell method is one of the most flexible approaches.In this method,a parameter is defined as a ratio of the volume open to water and air in a calculation cell to its cell volume.In the calculation,the same numerical procedure is applied to every cell and no explicit boundary conditions are needed at solid boundaries.The method is used to simulate flow through porous media,around solid bodies and over a moving seabed.The results compare well with experimental data and other numerical results.In our future work the porous cell method will be applied to more complex fluid-solid interaction situations.     

SEDS在船舶电力推进系统设计中的应用

电站是船舶电力推进系统中最重要的环节之一,借助SEDS平台,分析了不同电站配置方案对船舶电力系统的影响,为数字仿真应用于船舶电力系统设计提供了思路.     

虹桥综合交通枢纽开发融资策划

虹桥综合交通枢纽是上海城市交通的重大枢纽,属于城市大型交通基础设施.分析了虹桥综合交通枢纽的基本经济属性,对枢纽设施进行了拆分,并根据可经营性、可拆分性将枢纽设施分成4种类型;基于设施分类,对枢纽系统的投资平衡进行了研究,提出了4类设施不同的融资方式,以及由此所形成的投资分工和多元化投资主体结构.     

Autonomous vehicle self-localization based on abstract map and multi-channel LiDAR in urban area

Accurate vehicle self-localization is significant for autonomous driving. The localization techniques based on Global Navigation Satellite System (GNSS) cannot achieve the required accuracy in urban canyons. On the other hand, simultaneous localization and mapping (SLAM) methods suffer from the error accumulation problem. State-of-the-art localization approaches adopt 3D Light Detection and Ranging (Lidar) to observe the surrounding environment and match the observation with a priori known 3D point cloud map for estimating the position of the vehicle within the map. However, storing the massive point cloud needs immense storage on the vehicle, or it should be stored on servers, which makes the simultaneous downloading of the map by multiple vehicles another challenge. In this study, rather than employing the point cloud directly as the prior map, we focus on the abstract map of buildings, which is easy to extract, and at the same time apparently observable by Lidar. More especially, we proposed vehicle localization methods based on two different abstract map formats representing urban areas. The first format is the multilayer 2D vector map of building footprints, which represents the building boundaries using vectors (lines). The second format is the planar surface map of buildings and ground. These map formats share the same idea that the uncertainty (deviation) of each vector or planar surface is calculated and included in the map. Later in the localization phase, the observed data from Lidar is matched with the abstract map to obtain the precise location of the vehicle. Experiments conducted in a dense urban area of Tokyo show that even though we significantly shrank the map size, we could preserve the mean error of the localization.     

LPG船的一种新型舷侧耐撞结构研究

该文基于圆管碰撞能量吸收原理,提出了一种新型LPG船舷侧耐撞结构,经与常规LPG船舷侧结构的比较表明,此新型舷侧结构具有良好的耐撞性能。     

盐田港二期工程设计情况介绍

文章介绍了盐田港二期工程设计概况、设计范围和主要设计内容。     

剩余法在水运建设项目围海造地工程财务评价中的应用

剩余法在房地产开发项目财务评价中应用较为普遍,本文将其引用到水运建设项目围海造地工程的财务评价中,结合某围海造地工程实例,说明该评价方法的可行性,可以做为水运建设项目中围海造地工程财务评价的一种参考方法。     

北京地铁接触轨供电系统的安全管理

北京地铁运营40年来一直采用DC750V接触轨（三轨）供电制式,没有因接触轨事故而影响行车或引发人身伤亡。北京地铁接触轨供电系统安全防护的有效措施主要有：确定安全可靠的牵引供电主接线方式,制定进出地铁区间的安全管理办法,在涉及接触轨系统的作业时先将走行轨和接触轨短封。阐述北京地铁在接触轨及牵引供电系统安全防护方面的日常管理措施。     

项目管理公司职工教育培训工作的探索与实践

开展职工教育培训,是提高职工队伍整体素质,适应企业持续发展的必然需求。该文结合建设工程项目管理公司人力资源管理特点,就如何开展职工教育培训工作进行了初步的探讨,介绍了开展教育培训的一些具体做法和实体案例,可供同行借鉴。     

微型纯电动汽车的系统构型与关键参数设计

本文中为微型纯电动汽车选定了轮毂电机驱动方式,并研究其构型和参数设计.首先构建了由整车控制器、电机控制器和电池管理系统组成的分布式控制系统以及能量回馈制动与液压制动协调配合的并联复合制动系统.然后进行关键部件的参数设计,先确定整车目标性能参数,再根据车辆动力学计算与Matlab/Simulink仿真结果,确定轮毂电机和动力电池的性能参数并进行选型.最后通过仿真与整车试验验证整车性能满足设计指标.