Efficient estimation of extreme non-linear roll motions using the first-order reliability method (FORM)

In on-board decision support systems, efficient procedures are needed for real-time estimation of the maximum ship responses to be expected within the next few hours, given online information on the sea state and user-defined ranges of possible headings and speeds. For linear responses, standard frequency domain methods can be applied. For non-linear responses, as exhibited by the roll motion, standard methods such as direct time domain simulations are not feasible due to the required computational time. However, the statistical distribution of non-linear ship responses can be estimated very accurately using the first-order reliability method (FORM), which is well known from structural reliability problems. To illustrate the proposed procedure, the roll motion was modelled by a simplified non-linear procedure taking into account non-linear hydrodynamic damping, time-varying restoring and wave excitation moments, and the heave acceleration. Resonance excitation, parametric roll, and forced roll were all included in the model, albeit with some simplifications. The result is the mean out-crossing rate of the roll angle together with the most probable wave scenarios (critical wave episodes), leading to user-specified specific maximum roll angles. The procedure is computationally very effective and can thus be applied to real-time determination of ship-specific combinations of heading and speed to be avoided in the actual sea state.     

Underwater sonar image recognition based on gray-spatial histograms

A new gray-spatial histogram is proposed, which incorporates spatial information with gray compositions without sacrificing the robustness of traditional gray histograms. The purpose is to consider the representation role of gray compositions and spatial information simultaneously. Each entry in the gray-spatial histogram is the gray frequency and corresponding position information of images. In the experiments of sonar image recognition, the results show that the gray-spatial histogram is effective in practical use.     

基于GIS技术的地质灾害易发程度分区评价系统

文中结合大连市区地质灾害调查与区划项目,建立了一套基于GIS的地质灾害易发程度分区评价模型。并将多级模糊模式识别模型引入到地质灾害易发程度分区评价中,研究和探讨GIS与地质灾害易发程度分区评价模型的结合,为解决地质灾害调查与区划项目中地质灾害易发程度分区提供新的理论方法。     

研究SoLoMo概念与LBS技术融合的汽车4S店售后服务

汽车4S店依赖进销巨额价差获得盈利的时代逐渐消逝,做好销售的同时,借助网络渠道促进汽车4S店售后服务品质提升、规模效益增长和客户群体的稳定是其可持续发展的主要途径。本文通过引入SoLoMo概念与LBS技术完善传统的O2O模式,进而扩大4S店的服务推广以及针对特定登陆位置为客户有效提供差异化服务。从保证售后服务质量为出发点,在O2O平台上建立维修返修处理应用流程,以全新理念、全新方法来提高汽车售后质量,满足客户需求。     

汽车轮毂轴承失效模式分析及性能提升

轮毂轴承是汽车非常重要的安全部件,本论文列举某车型路试过程中轮毂轴承单元失效的问题进行分析,针对其失效的原因采取相应轴承性能提升的措施。     

一种优化的船体外板三维点云数据提取方法

针对水火弯板机检测系统中船舶外板三维点云数据自动提取过程存在边缘噪点、板下贴合垫木识别效率低以及外板边缘拟合等问题,提出一种优化DBSCAN聚类算法,首先根据现场加工环境精简点云,利用网格划分来建立外板点云拓扑模型,然后根据DBSCAN密度聚类算法搜索出外板点云,最后采用最小二乘法进行边缘拟合。结果表明,该算法能有效识别外板边缘,提取出外板点云。     

辽宁交通地理信息平台建设

地理信息系统建设是智能交通系统的重要研究内容之一.本文讨论了企业级GIS系统框架的建立以及数据库的设计和实现.同时介绍了电子地图、数据的分类和内容.     

Data assimilation with the Ensemble Kalman Filter and the SEIK filter applied to a finite element model of the North Atlantic

Currently there are different approaches to filter algorithms based on the Kalman filter. One of the most used filter algorithms is the Ensemble Kalman Filter (EnKF). It uses a Monte Carlo approach to the filtering problem. Another approach is given by the Singular Evolutive Extended Kalman (SEEK) and Singular Evolutive Interpolated Kalman (SEIK) filters. These filters operate explicitly on a low-dimensional error space which is represented by an ensemble of model states. The EnKF and the SEIK filter have been implemented within a parallel data assimilation framework in the Finite Element Ocean Model FEOM. In order to compare the filter performances of the algorithms, several data assimilation experiments are performed. The filter algorithms have been applied with a model configuration of FEOM for the North Atlantic to assimilate the sea surface height in twin experiments. The dependence of the filter estimates on the represented error subspace is discussed. In the experiments the SEIK algorithm provides better estimates than the EnKF. Furthermore, the SEIK filter is much cheaper in terms of computing time.     

固结拉索近似频率方程求解条件的对比研究

利用文献[1]得出的近似频率方程和求解条件,结合Rayleigh定理和经典弦的频率公式,推导拉索近似频率方程的求解条件及其参考值,扩大近似频率方程的使用范围。通过数值算例,将文献[1]和本文求解条件的合理性和可靠性进行对比研究,其结果可用于快速测试拉索索力。     

世界汽车灯具及灯光技术研究

文章是国内外汽车灯具的技术分析和总结。文章首先简介了汽车灯具的分类及基本结构；其次细述了如何依照国标对灯具进行配光性能检测和各类环境试验；最后揭示了世界汽车灯具的未来发展趋势。是汽车灯具行业的纲领性技术文件，是目前世界主要车灯技术的集大成者，对从事汽车灯光的工作人员具有重要指导作用．