基于ANN星识别算法的仿真平台

星敏感器是一种高精确度的姿态测量仪器，它通过对观测到的星点进行识别来计算姿态。为了能够较好地测试和验证星识别系统的性能，设计了一个基于ANN算法的星识别仿真平台。通过对该星识别仿真平台性能的测试，表明该仿真平台能够方便，实时地测试星识别算法的性能与正确性，因此说它是一种具有较好实用价值的星识别仿真平台。     

Mixed analysis of shell and solid elements using the overlaying mesh method

 This article presents a mixed method of analyzing shell elements and solid elements using the overlaying mesh method. In the structural design of a ship's hull, the shell elements are used for the global model. However, the solid elements are necessary to analyze the stress concentration zones or the vicinity of a crack. In such cases, the models are analyzed using zooming analysis, in which the results of a global model analysis are transferred to a local model analysis by imposing boundary conditions. This method is more advantageous than zooming analysis in terms of the accuracy of the solution and the modeling flexibility. Some examples of a plate model with a cracked surface or with a projection are shown in order to demonstrate the effectiveness of the method. Received: August 6, 2002 / Accepted: November 25, 2002 Address correspondence to: S. Nakasumi (sumi@nasl.t.u-tokyo.ac.jp) Updated from the Japanese original, which won the 2002 SNAJ prize (J Soc Nav Archit Jpn 2001;189:219–224; and 190:655–662)     

Numerical simulation of the flow about self-propelling tanker models

A time-marching CFD simulation is performed for self-propelling ships. The flow about the hull is simulated by the finite-volume method, and the propeller action is approximated as a propeller disk for which the solution is given by a simplified propeller model. The interaction of two flow models is treated in a time-marching procedure converging towards the steady self-propelling condition. This method is applied to five tanker models, and detailed comparisons are made between the simulated results and corresponding experimental results. It is shown that the flow field in the self-propelling condition is qualitatively well reproduced in the simulation, and the estimated thrust deduction factors for the five hull forms agree well with measured ones. However, the effective wake factors are underestimated, since the Reynolds number in the simulations differs from that in the experiment.     

装配式公路钢桥承载力的有限元分析

指出装配式公路钢桥设计中所采用的简化计算方法的不足,使用大型有限元软件ANSYS对其受力情况和承载力进行了分析,并与简化计算方法作了对比,得出了一些规律性的结论,对实际应用具有指导意义。     

薄壁箱梁剪滞剪切效应自振特性分析

在推导考虑剪力滞、剪切变形双重效应的单元刚度矩阵与等效结点荷载矩阵的基础上[1],进一步推导出考虑双重效应的单元质量矩阵,从而形成完整的薄壁箱梁考虑双重效应的矩阵分析体系,可方便地纳入矩阵位移法程序系统,为常见的薄壁连续梁等复杂结构的剪力滞效应分析提供一种计算手段。利用自编程序ZLBOX对薄壁箱型简支梁和悬臂梁考虑剪力滞、剪切变形双重效应时的自振特性进行了分析,所得结果与ANSYS实体单元计算结果符合良好。计算结果表明,剪力滞、剪切变形双重效应使薄壁箱梁的自振频率降低,剪力滞效应占双重效应的85%以上,双重效应对高阶频率的影响比低阶频率的影响大。     

惠州港在珠江三角洲战略定位的思考

珠江三角洲各地港口建设往往只从本地区角度考虑,在一定程度导致各市港口性质相似、功能雷同,并为争夺货源进行恶性竞争。论文分析了惠州港的优势,再用层次分析法对集装箱港口竞争的关键要素进行定性和定量分析,得出珠江三角洲9个港口发展集装箱码头建设的权重。为惠州港的港口资源在珠三角洲港口群中的最优配置提供相关的研究资料。     

同步发电机参数辨识的相关方法探讨

随着电网安全及稳定运行问题的重要性日益突出,基于获得准确的系统模型和参数辨识方法,优化同步发电机相关参数将是十分有意义的。本文针对当今几种比较典型的参数辨识方法做了系统的介绍,通过比较得出何种方法对于同步电机的参数辨识是最适合的。     

Estimation of origin‐destination matrices for a multimodal public transit network

This paper presents a procedure for the estimation of origin‐destination (O‐D) matrices for a multimodal public transit network. The system consists of a number of favored public transit modes that are obtained from a modal split process in a traditional four‐step transportation model. The demand of each favored mode is assigned to the multimodal network, which is comprised of a set of connected links of different public transit modes. An entropy maximization procedure is proposed to simultaneously estimate the O‐D demand matrices of all favored modes, which are consistent with target data sets such as the boarding counts and line segment flows that are observed directly in the network. A case study of the Hong Kong multimodal transit network is used to demonstrate the effectiveness of the proposed methodology.     

港口腹地划分的两种新方法探讨--以大连国际航运中心为例

引入经济地理学的新理论成果———圈层结构法和点轴法,提出了圈层结构划分法和点轴结构划分法两种新的港口腹地划分方法,并应用这两种新方法对大连国际航运中心港口腹地范围的界定与划分进行实例分析。与以往的行政区划法、经济区域法等港口腹地划分方法相比,这两种方法更加注重对港口原有腹地的细分,更接近于港口腹地的实际状况,进而有利于港口企业的经营发展。     

组合结构力法分析

本文应用集合概念，对组合结构作了形式化描述。通过矩阵分析，导出了力法方程的统一列式。给出了算法实施的流程框图和具体算例。