GIS环境下污水管网设计流量的快速计算

针对ＧＩＳ环境下污水管网设计问题，提出了一种快速计算管段设计流量的方法——递归方法。分析了递归的原理、链式表的建立以及递归算法的具体实现等，并以实例阐述了递归计算的各个步骤     

利用OpenGL显示列表技术实现GIS对象的符号化

介绍了利用OpenGL显示列表技术和各类符号相互嵌套的方法,实现了GIS对象符号化的过程。     

Comment on G. Wansard and F. Mezquita, The response of ostracode shell chemistry to seasonal change in a Mediterranean freshwater spring environment

In a study of the minor element chemistry of ostracode shells, Wansard and Mezquita (2001) concluded that the Mg/Ca and Sr/Ca of the ambient water controlled the respective ratios in ostracode calcite. Contrary to their conclusion that minor element chemistry is not influenced by temperature, we find a very strong statistical correlation (r = 0.97) between temperature and shell chemistry in their data. This discrepancy apparently arises due to their use of a partition coefficient model of shell chemistry that masks a number of strong correlations in their data. We argue here that the partition coefficient model is not appropriate for this biologically-mediated carbonate, and that a broader range of possible controls on shell chemistry needs to be tested.     

微博用户的中国传统节日感知及区域差异研究

随着智能移动终端和社交网络应用的普及,越来越多的人愿意通过社交网络平台进行交流和表达自己的情感,因此产生了大量含有地理位置、文本内容等多种信息的用户生成数据,为大数据时代的城市研究及特定时空间内个体感知和行为活动研究提供新的数据源。本文基于2012-2014年约54万条微博用户数据,探测民众对包括春节、元宵节、清明节、端午节和中秋节在内的中国传统节日的情感表达和关注热点,以期发现在城市化与全球化影响下,人们对中国传统节日的认知变化和区域特征。通过Python 3.6进行词频分析及LDA主题模型分析可知：① 春节是中国人主题感知最为强烈的节日,且多为对新年美好祝愿的表达,其次是中秋节,以回家团聚为主,另外情人节也成为一个显性的节日;② 传统节日期间,出行方式以飞机和汽车为主,机场和高速成为与节日活动密切相关的场所;③ 共识性岁时习俗整体感知较好,但各地域特色节庆活动及饮食习俗在表现形式上有所差异,且差异在逐渐减小;④ 词频分析较好地反映了微博用户对中国传统节日的普遍感知及具有地方特色的区域差异,而LDA主题模型分析能够反映一定的传统节日主题聚类结果,但对不同节日的主题聚类效果并不十分明显。     

中国海域助航标志信息平台的设计与实现

针对目前我国助航标志在航标表出版、航标信息更新及数字海图制图有关航标综合中存在的一些问题,设计建立中国海域助航标志信息平台,实现中国海域助航标志数据库更新维护和航标表出版的自动化,提供中国海域助航标志信息服务系统,并利用VC6．0语言及Mapobject控件和ArcInfo技术在数字海图制图综合中自动实现助航标志的综合和航标符号的准确表示。     

Geochemical effects of rapid sedimentation in aquatic systems: minimal diagenesis and the preservation of historical metal signatures

Rapid sedimentation exerts a pronounced influence on early sedimentary diagenesis in that there is insufficient time for a sediment particle to equilibrate in any one sediment layer before that layer may be displaced vertically by another layer. These sedimentation patterns are common in surface-water reservoirs whose sedimentation rates (1-10 cm yr^-1) are several orders of magnitude greater than those for natural lakes (0.01-0.5 cm yr^-1).Two examples of the effects of rapid sedimentation on geochemical metal signatures are presented here. Interstitial-water data (Fe) from two sites in the Cheyenne River Embayment of Lake Oahe on the Missouri River illustrate the effects of changing sedimentation rates on dissolved species. Rapid burial during high-flow yrs appears to limit early sedimentary diagenesis to aerobic respiration. Solid-phase metal data (Pb) from a site in Pueblo Reservoir on the upper Arkansas River in Colorado appear to record historical releases by flooding of abandoned mine sites upstream in Leadville, Colorado. Interstitial-water ammonia and ferrous Fe data indicate that at least one interval at depth in the sediment where solid metal concentrations peak is a zone of minimal diagenesis.The principal diagenetic reactions that occur in these sediments are aerobic respiration and the reduction of Mn and Fe oxides. Under slower sedimentation conditions, there is sufficient time for particulate organic matter to decompose and create a diagenetic environment where metal oxides may not be stable. The quasi-steady-state interstitial Fe profiles from Tidal Potomac River sediments are an example of such a situation. This occurs primarily because the residence time of particles in the surficial sediment column is long enough to allow benthic organisms and bacteria to perform their metabolic functions. When faster sedimentation prevails, there is less time for these metabolic reactions to occur since the organisms do not occupy a sediment layer for any length of time. Also, the quantity and quality of the organic matter input to the sediment layer is important in that reservoirs often receive more terrestrial organic matter than natural lakes and this terrestrial organic matter is generally more refractory than autochthonous aquatic organic matter.     

一种基于概率潜在语义模型的高分辨率遥感影像分类方法

针对高分辨率遥感影像中"同谱异物","同物异谱"现象对影像分类过程造成的干扰,将文本分析中的概率潜在语义模型应用于高分辨率遥感影像分类,提出一种无监督的遥感影像分类新方法.该方法首先利用均值漂移分割方法对影像进行分割构建图像区域集合,然后提取集合各区域中每个像元的Gabor纹理特征,并对这些特征进行聚类形成视觉词汇,最...     

曲线坐标系下线状要素名称注记定位模型的研究

提出了在数字空间描述线状要素的一种曲线坐标系,给定了在该坐标系下确定线状要素名称注记定位点的模型体系,并结合注记配置规则,对线状要素名称注记字隙的确定进行了建模,最后提出了曲线坐标系下线状要素名称注记优化配置的宏观逻辑。此方法、模型体系正确可行,实施简单。     

基于语义规则和词向量的台风灾害网络情感分析方法

灾害期间的舆情引导有助于维护社会稳定。社交媒体是舆论传播的重要渠道,通过微博评论了解用户的网络情感及关注的话题,可以帮助相关舆情监测部门掌握公众的关注热点,从而选择适当的干预节点来应对网络舆情,并对公众情绪进行疏导,这对于应急管理具有现实意义。现有的研究大多是利用有监督的机器学习方法进行情感分类,这需要人工进行语料的标注,工作量大。本文根据微博评论文本的特点,综合考虑情感词以及表情符号等多重情感源,构建了台风灾害领域情感词典。在此基础上,提出了一种基于情感词语义规则的情感倾向计算方法,以及基于词向量的话题聚类方法。首先,采集了近年5次台风灾害期间共计40多万条微博评论文本,基于大连理工情感词汇本体库进行扩展构建了台风灾害领域情感词典,结合PMI法构建表情符号词典,根据语义规则确定情感倾向,并使用3500条评论文本验证了该方法的有效性。然后,本文基于词向量、TF-IDF与K-means的聚类方法探索灾害期间热点话题。最后,以2020年4号台风“黑格比”为例,基于台风期间的5万余条微博评论文本进行了舆情情感分析,并识别出6类与台风相关的话题。通过时空分析发现,随着时间的推移,微博评论文本的数量发生一定变化,评论数量多的地区大都集中在沿海地区和经济水平高的地区,台风登陆当天浙江省的恐惧情感达到最高。结果表明,基于语义规则和词向量的台风灾害网络情感分析方法,能在类似灾害事件发生时为政府部门掌握和引导网络舆情提供辅助。     

An improved Bag-of-Words framework for remote sensing image retrieval in large-scale image databases

Due to advances in satellite and sensor technology, the number and size of Remote Sensing (RS) images continue to grow at a rapid pace. The continuous stream of sensor data from satellites poses major challenges for the retrieval of relevant information from those satellite datastreams. The Bag-of-Words (BoW) framework is a leading image search approach and has been successfully applied in a broad range of computer vision problems and hence has received much attention from the RS community. However, the recognition performance of a typical BoW framework becomes very poor when the framework is applied to application scenarios where the appearance and texture of images are very similar. In this paper, we propose a simple method to improve recognition performance of a typical BoW framework by representing images with local features extracted from base images. In addition, we propose a similarity measure for RS images by counting the number of same words assigned to images. We compare the performance of these methods with a typical BoW framework. Our experiments show that the proposed method has better recognition performance than that of the BoW and requires less storage space for saving local invariant features.