基于字符匹配算法组合的地理空间敏感属性检测系统

针对地理空间敏感属性检测实际需求,研究了多种字符匹配算法,通过比较分析,提出了基于字符匹配算法组合的地理空间敏感属性检测方法,开发出了检测系统,在实际生产中得以应用。经实践检验,算法组合在处理海量数据时保持高效率,利用系统可以大幅度提高敏感属性检测效率,同时保证了检测结果的准确性。     

Stellar variability in Trumpler 24. II

We present a second season of CCD time‐series observations of Trumpler 24 in Johnson B and V obtained in 2004. 18 new variable stars are found, 15 variables discovered in Paper I are discussed, and the variability class of 5 of them is given. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

房产专题信息分类与编码分析

房产地理信息分类编码是房产地理信息管理与应用、房产地理信息系统建设中最基本的问题。如果房产地理信息分类编码体系不合理,将增加系统建库工作量,影响房产地理数据库的使用和信息共享,甚至将缩短房产地理数据库的生命周期,造成巨大的损失。因此,建立完善的房产地理信息编码体系,对房产地理信息系统的建设、房产地理信息管理与应用目标的实现至关重要。根据在南京“数字房产”共享网络平台项目需求分析和数据整合实践中对房产管理业务与管理模型的理解,并考虑到城市各部门和城市间信息共享的需求,笔者提出了一种房产行业地理信息分类编码方案,对房产行业地理信息标准的制定工作具有积极意义。     

L and T brown dwarfs in the Ursa Major moving group

We have applied the “moving cluster” method to an archive of L and T brown dwarf stars to identify those stars which are members of the Ursa Major moving group.We show that five stars have proper motion directions which agree with the direction of motion expected for a cluster member, and which have proper motion distances in agreement with distances determined by trigonometrical parallax observations. We then use 2MASS data to produce an M _K versus J ‐ K _S colour magnitude diagram. The group members define an empirical 400 Myr isochrone, which is compared to theoretical models. This is the first cluster/group to have a known T dwarf member. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

State-of-the-art overview of the Loess Palaeolithic of Poland

In Poland, loess mainly occurs in the southern part of the country, in the Polish Uplands, and on the northern foreland of the Sudetes and the Carpathians. Most of these sediments come from the time of the last glaciation–the Vistulian (Weichselian) glaciation. Thin covers of loess from the penultimate glaciation have been preserved in Upper Silesia. Only a few sites from the Middle Palaeolithic remain in the loess. In the eastern part of Poland loess creates profiles several metres high. Discoveries in this zone represent the cultural sequence from the transition from the Middle to Upper Palaeolithic. We know more traces of various cultures from the Upper Palaeolithic exist. The study attempts to synchronise profiles from selected archaeological open-air sites, outlines of the history of research on loess sites, and attempts to explain terminological and conceptual issues. The issue of loess in the cave site profiles will not be discussed in the article.     

The impact of single natural vegetation elements on flow characteristics

In this experimental study, measurements were conducted to explore the impacts of different forms of individual natural vegetative elements within the flow domain on velocity and turbulence characteristics. All the experiments were performed in a flume measuring 26 m in length, 0·98 m in width and 0·85 m in depth, and real tree saplings were utilized to represent the vegetation element. In order to analyse this commonly observed nature phenomenon in floodplains, trees with wide trunks were classified into three groups on the basis of their volume versus height relation. Throughout the velocity measurements three acoustic Doppler velocimeters were employed. Time‐averaged velocity, streamwise and vertical turbulence intensities and turbulent kinetic energy parameters were examined. Additionally, a formulation that gives the velocity profile at a certain distance downstream of vegetation was introduced and the validity of the proposed formulation was checked with experimental data. It is seen that despite their porous structures, the presence of vegetation considerably disturbs the flow field and dissipates a remarkable amount of energy by turbulence. Copyright © 2008 John Wiley & Sons, Ltd.     

基于FY-3D微波成像仪的中国陆地区域地表温度反演及验证

地表温度是地表与大气热量平衡中的关键参数,在气候、生态、水文等研究领域发挥着重要作用.选取2019年11月-2020年10月风云三号D星(FY-3D)微波成像仪亮温数据,对其进行数据重采样和异常像元剔除等预处理,采用UMT(University of Montana land surface retrieval alg...     

CPU+GPU异构环境下数据密集型矢量多边形地理大数据并行框架

本文提出了面向CPU+GPU异构环境的数据密集型矢量多边形地理大数据并行计算框架(PFGAP)。PFGAP将数据密集型矢量多边形地理大数据的并行计算分解为算子、数据、粒度、并行环境及任务调度5个模块,分别设计相应的负载均衡并行计算策略;通过封装并行计算实现细节及数据密集型多边形算子的快速并行化。试验采用多边形三角剖分、栅格化及投影变换作为测试算例,采用土地利用数据作为测试数据,在不同类型的并行环境中计算并行效率。结果表明,PFGAP能很好地适用于不同类型的数据集、算子及并行计算环境。利用PFGAP实现的并行算法显著地降低了串行执行时间,取得了40.03的最优并行加速比。试验还分别测试了各个模块涉及的并行策略,结果表明取得的并行效率优于现有并行策略。     

明渠水流自掺气发展区水气结构分析

为研究明渠水流自掺气发展区内水气结构特征,采用针式掺气流速仪对自掺气发展区内气泡尺寸与数量进行了试验研究,比较了气泡尺寸与数量随自掺气发展的变化规律,结果显示,同一水流断面上,随着掺气浓度的减小,气泡弦长尺寸分布范围与弦长平均值逐渐减小,掺气区内小尺寸气泡在数量上占有较大的比例,而大尺寸气泡则在含气量上占有较大的比例,分析认为从水面附近高掺气浓度区至自掺气区域底缘低掺气浓度区,明渠自掺气水流水气结构发展过程为“水面变形为主—水面变形与个体空气泡共存—个体空气泡”,为进一步研究明渠自掺气形成机理提供了一定的参考。