Risk Based Optimal Inspection and Repair Planning for Ship Structures Subjected to Corrosion Deterioration

A framework of risk based inspection and repair planning was presented to optimize for the ship structures subjected to corrosion deterioration. The planning problem was formulated as an optimization problem where the expected lifetime costs were minimized with a eonstraint on the minimum aceeptable rehability index. The safety margins were established for the inspection events, the repair events and the failure events for ship struetures. Moreover, the formulae were derived to calculate failure probabihties and repair probabilities. Based on them, a component subjected to corrosion is investigated for illustration of the process of selecting the optimal inspection and repair strategy. Furthermore, some sensitivity studies were provided. The results show that the optimal inspection instants should take place before the reliability index reaches the minimum acceptable reliability index. The optimal target failure probability is 10^-3. In addition, a balance can be achieved between the risk cost and total expected inspection and repair costs by means of the risk-based optimal inspection and repair method, which is very effective in selecting the optimal inspection and repair strategy.     

海上油田油轮外输系统优化分析

对海上油田油轮外输系统进行了分析 ,建立了系统优化的数学模型。选用模矢搜索法、单纯形算法和模拟退火算法三种优化方法进行了计算 ,得出在对某些非线性问题进行优化时 ,利用模拟退火算法和直接最优化方法 (如单纯形法 )相结合 ,既能保证得到全局最优解 ,又能减少计算时间。通过实例计算 ,得出油轮外输系统适用于离岸距离较远、产量较小的油田 ,其外输费用随离岸距离的增加变化非常小 ,但随油田产量的增加而增加较大     

GNSS三频周跳探测与修复算法

针对使用组合观测值探测周跳存在不敏感周跳且难以修复的问题,研究了三频周跳探测与修复的几何原理,从几何角度研究了多个相位无几何组合(GF)探测周跳的异同,以及加入MW组合后的效果,并搜索了相应的不敏感周跳。提出了以对应的横截面积最小为原则选取组合量的方法。经北斗三频实测数据验证,GF组合的数量以两个为宜,加入MW组合后不敏感周跳进一步减少,优化选取的两个GF组合和MW组合联合探测周跳仅存在一个不敏感周跳,且探测到的周跳均能正确修复。     

Oracle数据库矢栅数据一体化存储与管理

当前多源异构空间数据存储和管理存在流转难度大、存储不统一、效率不高等问题。本文将关系数据库与空间数据引擎技术结合,提出了一种基于Oracle的面向对象的矢栅数据一体化存储与管理方法。该方法首先建立了矢栅一体化存储模型并优化了检索方法,然后据此构建了数据无缝流转框架,实现了多源异构矢栅数据的统一存储与高效管理。通过与国际领先的同类软件ArcSDE进行测试对比,该方法具有更高的数据流转性能及更优的查询检索效率。     

《中华人民共和国影像地图》的设计与编制

以资源三号卫星影像为主要数据源,以影像处理为重点,探讨在全国尺度上,影像效果优化的方法以及影像与矢量数据协调一致性问题,设计编制了3 m×2.2 m的《中华人民共和国影像地图》挂图,弥补了我国国产影像大尺寸挂图编制领域的空白。     

地面人工影响天气指挥系统产品算法优化

基于SWAN的TITAN产品、安全射界图技术,构建了地面人工影响天气指挥系统。为进一步提高该系统预警、作业建议产品的时效性和准确性,本文优化了预警和作业建议产品算法:1将原TITAN识别区域预警优化为TITAN外推路径区域的预警,减少了预警的漏报;2针对没有本站雷达的地市,使用全省雷达拼图数据存在时间滞后性问题,引入了数据延迟设置功能,对预警和建议产品的时间进行订正。通过算法的优化,系统可较好地满足地面人工影响天气作业指挥的业务需求,具有一定的推广价值。     

A GPU-accelerated adaptive kernel density estimation approach for efficient point pattern analysis on spatial big data

Kernel density estimation (KDE) is a classic approach for spatial point pattern analysis. In many applications, KDE with spatially adaptive bandwidths (adaptive KDE) is preferred over KDE with an invariant bandwidth (fixed KDE). However, bandwidths determination for adaptive KDE is extremely computationally intensive, particularly for point pattern analysis tasks of large problem sizes. This computational challenge impedes the application of adaptive KDE to analyze large point data sets, which are common in this big data era. This article presents a graphics processing units (GPUs)-accelerated adaptive KDE algorithm for efficient spatial point pattern analysis on spatial big data. First, optimizations were designed to reduce the algorithmic complexity of the bandwidth determination algorithm for adaptive KDE. The massively parallel computing resources on GPU were then exploited to further speed up the optimized algorithm. Experimental results demonstrated that the proposed optimizations effectively improved the performance by a factor of tens. Compared to the sequential algorithm and an Open Multiprocessing (OpenMP)-based algorithm leveraging multiple central processing unit cores for adaptive KDE, the GPU-enabled algorithm accelerated point pattern analysis tasks by a factor of hundreds and tens, respectively. Additionally, the GPU-accelerated adaptive KDE algorithm scales reasonably well while increasing the size of data sets. Given the significant acceleration brought by the GPU-enabled adaptive KDE algorithm, point pattern analysis with the adaptive KDE approach on large point data sets can be performed efficiently. Point pattern analysis on spatial big data, computationally prohibitive with the sequential algorithm, can be conducted routinely with the GPU-accelerated algorithm. The GPU-accelerated adaptive KDE approach contributes to the geospatial computational toolbox that facilitates geographic knowledge discovery from spatial big data.     

海洋平台结构动力响应优化设计与灵敏度分析

研究了海洋平台结构动力响应优化设计以结构动力响应的灵敏度计算方法。给出了结构稳态频率响应和瞬态时程响应的灵敏度分析算法，并通过数值试验讨论了瞬态响应灵敏度分析算法的精度和差分法中变量摄动量的影响。在JIFEX软件中实现了结构动力响应灵敏度计算，建立海洋平台结构优化模型和求解方法。数值算例表明了本文方法和程序的有效性。     

黄河三角洲高效生态经济区土地利用结构优化与调整初探

黄河三角洲具有独特的地理区位,黄河三角洲高效生态经济区规划上升为国家战略后,黄河三角洲高效生态经济区（以下简称黄三角）的开发与建设引起社会广泛的关注,土地利用结构调整与优化也成为新常态下具有重要意义的课题。该文探讨了黄三角地区土地资源利用结构的特点,分析了土地利用中存在的结构性问题,探索了土地利用结构调整、优化、升级趋势和方向,提出了土地利用结构调整中应该注意的问题,为发挥区域土地资源优势,促进黄三角经济社会又好又快发展提供一定的借鉴。