海洋石油管线探测多波束剖面声纳设计

针对海洋石油管线探测多波束剖面声纳的高速、大容量的实时信号处理任务,以及声纳系统进一步扩展的需求,设计并实现了一种基于IP网络互连的、以并行DSP为处理节点的多波束剖面声纳系统.该系统应用于海底石油管线探测与定位,系统中的每个处理节点与数据采集转换部分采用TCP/IP网络连接,可以通过物理上添加一个或多个处理节点成倍的提高系统的信号处理能力,而在软件上无须大的改动.通过电联调与水槽试验,验证了系统的可行性和稳定性,该设计为高速水声阵列信号实时处理系统提供了一种全新的解决思路.     

A new model of edge-to-edge contact for three dimensional discontinuous deformation analysis

A robust contact theory can be regarded as key to three dimensional discontinuous deformation analyses (3D-DDA). Not only must this theory provide an efficient algorithm to judge the type and location of contacts but also it must be able to present comprehensive formulations for every kind of contact (open, sliding and locked contact). There are six types of contact in three dimensional discontinuous deformation analyses (vertex-to-vertex, vertex-to-edge, vertex-to-face, edge-to-edge, edge-to-face and face-to-face) that can be converted to vertex-to-face and edge-to-edge contacts. This paper presents a new model of edge-to-edge contact to three dimensional discontinuous deformation analyses (3D-DDA). This new model considers both kinds of edge-to-edge contact (cross-over and parallel edge-to-edge contact) and presents a criterion for inter-penetration. Sub matrices of normal and shear spring and friction force are derived by geometrical analysis and penalty method. This new model is implemented in a 3D-DDA computer programme, and the example results demonstrate the validity of the model.     

聚合物驱组合段塞分注实验研究

萨尔图油田南二区东部140号断层以东地区葡11—4油层,以多段多韵律和正韵律沉积为主,平均孔隙度30．0％,平均空气渗透率1980×10^-3μm2。水驱结束时该油层平均含水92％,采出程度39．5％。计划对该区块实施聚合物驱开采。以往经验认为,组合段塞调整注聚技术能够有效改善流度控制作用。然而对组合注入情况下如何进一步提高驱油效果、注入井分注时机、层段注入强度对开发效果有何影响却很少探讨。通过室内驱油实验,在聚驱的组合段塞注入不同时机（水驱空白阶段、含水下降阶段、含水稳定阶段、含水回升阶段）下调整注入强度实施分注以及在含水回升分注基础上进一步调整注入强度,同时对比不分注实验,评价各方案驱油效果。实验表明：不实施分注时聚驱采收率在水驱基础上提高了19．07个百分点,而组合段塞注入时实施分注均能够在不分注基础上进一步提高驱油效果;空白水驱时实施分注采收率提高幅度最大,为26．55个百分点;随着分注时机的滞后采收率提高幅度增加值依次递减,分注时机越早越好。     

基于集群的影像并行OPTA算法研究

并行计算是提高海量遥感影像细化处理速度的有效途径.基于对OPTA细化算法的分析,深入研究OPTA细化并行算法中数据划分和数据通信优化等关键问题,提出一种适合集群并行处理的通信优化并行算法,实验证明该算法具有良好的加速比,适合集群计算环境下海量遥感影像的细化处理.     

锥束CT图像重建算法的快速实现

本文基于锥束CT滤波反投影重建的FDK算法,通过两种算法改进并结合基于共享内存的OpenMP并行技术和代码优化,实现了锥束CT图像的快速重建。基于锥束CT实际投影数据的重建结果表明,图像重建速度得到了较大的提高,断层图像重建质量与FDK原型算法相当。     

岩体结构面水力学模型及应用

本文提出岩体结构面适应性平行板模型和该模型的参数确定方法——三段压水试验新解释,新的模型有益于克服将结构面圆盘模型应用于地下水模拟中的局限性;基于结构面起伏度对地下水流动的影响,导出了起伏度修正系数解析表达式。     

分布式水文模型的GPU并行化及快速模拟技术

分布式水文模型对流域水文过程的应用深度及广度不断加深,常与数值天气及气候预报相结合,面临巨大的计算量。近年来GPU技术的进步使普通电脑能够实现高效而又廉价的并行计算。提出了资料插值、单元产流以及单元汇流采用GPU并行计算,马斯京根法河道汇流采用一种非并行的递归方法。基于笔记本电脑和NVIDIA GPU/CUDA结合C#语言,由分布式新安江模型在沂河流域的模拟应用表明,降水量空间插值及新安江产流的并行执行效率为普通CPU上C#的8~9倍。使用直接递归法实现马斯京根汇流演算比以往采用汇流次序表的执行效率提升0.5~0.9倍。     

大型GNSS观测网的并行计算

CGCS2000精化及其全球拓展需要采用最新的模型,处理长期积累的大型GNSS观测网数据,大型GNSS网联合、快速和协同解算是空间基准精化、维持与服务的重要技术方向.在大数据技术背景下,以并行计算、云计算为代表的高性能计算技术逐渐成为大规模数据处理的首选方法.针对海量、多源、异构GNSS数据在解算处理与平差分析等方面面...     

Leveraging parallel spatio-temporal computing for crime analysis in large datasets: analyzing trends in near-repeat phenomenon of crime in cities

ABSTRACT

Crime often clusters in space and time. Near-repeat patterns improve understanding of crime communicability and their space–time interactions. Near-repeat analysis requires extensive computing resources for the assessment of statistical significance of space–time interactions. A computationally intensive Monte Carlo simulation-based approach is used to evaluate the statistical significance of the space-time patterns underlying near-repeat events. Currently available software for identifying near-repeat patterns is not scalable for large crime datasets. In this paper, we show how parallel spatial programming can help to leverage spatio-temporal simulation-based analysis in large datasets. A parallel near-repeat calculator was developed and a set of experiments were conducted to compare the newly developed software with an existing implementation, assess the performance gain due to parallel computation, test the scalability of the software to handle large crime datasets and assess the utility of the new software for real-world crime data analysis. Our experimental results suggest that, efficiently designed parallel algorithms that leverage high-performance computing along with performance optimization techniques could be used to develop software that are scalable with large datasets and could provide solutions for computationally intensive statistical simulation-based approaches in crime analysis.