A SIMILARITY MEASURE FOR CHEMICAL DATA: APPLICATIONS TO CLUSTER ANALYSIS

The results of unsupervised pattern recognition methods are critically dependent on the measure ofsimilarity used for clustering objects. There is little a priori information available on the relative utilityof various similarity measures. We introduce here an alternative similarity measure based on the metrictensor measure (MTM). Two standard clustering strategies are tested with the proposed similaritymeasure: hierarchical clustering and the K-median method. As data we use the ARCH obsidian data,a data set on Hungarian coal, and trace element data on Hungarian paprika. Differences from theMahalanobis distance measure are described for intraclass relations.     

Assessing similarity matching for possible integration of feature classifications of geospatial data from official and informal sources

One difficulty in integrating geospatial data sets from different sources is variation in feature classification and semantic content of the data. One step towards achieving beneficial semantic interoperability is to assess the semantic similarity among objects that are categorised within data sets. This article focuses on measuring semantic and structural similarities between categories of formal data, such as Ordnance Survey (OS) cartographic data, and volunteered geographic information (VGI), such as that sourced from OpenStreetMap (OSM), with the intention of assessing possible integration. The model involves ‘tokenisation’ to search for common roots of words, and the feature classifications have been modelled as an XML schema labelled rooted tree for hierarchical analysis. The semantic similarity was measured using the WordNet::Similarity package, while the structural similarities between sub-trees of the source and target schemas have also been considered. Along with dictionary and structural matching, the data type of the category itself is a comparison variable. The overall similarity is based on a weighted combination of these three measures. The results reveal that the use of a generic similarity matching system leads to poor agreement between the semantics of OS and OSM data sets. It is concluded that a more rigorous peer-to-peer assessment of VGI data, increasing numbers and transparency of contributors, the initiation of more programs of quality testing and the development of more directed ontologies can improve spatial data integration.     

Unveiling movement uncertainty for robust trajectory similarity analysis

Trajectory data analysis and mining require distance and similarity measures, and the quality of their results is directly related to those measures. Several similarity measures originally proposed for time-series were adapted to work with trajectory data, but these approaches were developed for well-behaved data that usually do not have the uncertainty and heterogeneity introduced by the sampling process to obtain trajectories. More recently, similarity measures were proposed specifically for trajectory data, but they rely on simplistic movement uncertainty representations, such as linear interpolation. In this article, we propose a new distance function, and a new similarity measure that uses an elliptical representation of trajectories, being more robust to the movement uncertainty caused by the sampling rate and the heterogeneity of this kind of data. Experiments using real data show that our proposal is more accurate and robust than related work.     

中国南极火成岩数据库数据结构和数据标准化的研究

根据南极火成岩信息和数据类型多、数据关系复杂、样品间数据完整性和精度差异大的特点，中国南极火成岩数据库划分为主库、来源文献、岩体地质学、岩石学、主要氧化物、稀土元素、痕量元素和同位素８个数据库。通过岩体系统号、样品系统号和来源文献号三个字段使８个数据库相互关联。中国南极火成岩数据库包括了１４０多个基本字段，存储火成岩岩石描述信息和分析数据。根据国内外火成岩数据标准化的现状的分析，中国南极火成岩数据库采用了国际地科联岩石学数据库分委会规定的标准词汇和代码，并利用代码－名词术语转换技术改善了用户界面     

地质灾害的非线性数据处理与建模技术

本文简略地介绍了几种地质灾害数据处理与建模的非线性方法,主要包括GMDH自组织建模技术、神经网络方法。GMDH是一种高阶非线性回归建模方法,它是以简单的二元二次回归方程为基础,通过"代复一代"的"生产"过程,客观、自动地求得实际资料的非线性模型。而神经网络则是用工程技术手段模拟生物神经网络的结构特征和功能特征的一类人工系统。与常规统计方法相比,神经网络最突出的优点为它是通过对网络的学习和训练,来掌握变量之间的非线性关系。因此,其处理复杂问题的能力更强大。实例检验效果表明,这些非线性数据处理与建模技术考虑了地质灾害问题的非线性特性,其比基于常规统计理论的数据处理方法的精度要高得多。     

ON THE VALIDATION OF MODELS

Traditional methods of evaluating geographic models by statistical comparisons between observed and simulated variates are criticized. In particular, it is suggested that the correlation coefficient (r), its square and tests of their statistical significance are inadequate for such purposes. The root mean squared error (RMSE) and related measures as well as a new index of agreement (d) are alternatively presented as superior indices for making such comparisons. Arguments are made for increasing the number of digital algorithms and data plots being published.     

干热退化山地不同类型侵蚀沟生物生态工程治理试验研究

冲沟是生态环境治理和控制泥石流活动的关键地段。结合云南南涧县城后山泥石流生物生态工程治理试验示范研究,总结出由土石混砌与土木筑造结构的生物谷坊,浆筑结构拦坝和谷坊等组成的沟道侵蚀治理方法,并成功地进行了相应的生物坝系建设,筛选出大叶桉,赤桉,马鹿花,台湾相思,马占相思,新叶合欢,夹竹桃等一批适宜干热生境和沟道植被恢复及防护林建设的植物种类,同时采取冲沟与谷坡同时整治,生物治理与调蓄水措施相结合的坡面治理方法。结果表明,这些生物生态工程措施对于防止沟床侵蚀,抑制泥石流活动和护床固坡效果显著。     

县域尺度下生态系统服务供需匹配及生态建设 ——以陕西省为例

利用生态系统服务价值量、社会经济数据,并通过标准化及冷热点等方法分析了陕西省所有县级行政单位ES供需的数量匹配和空间匹配特征,并以匹配结果为依据,划分生态建设类型,提出针对性的建设措施。结果表明:陕西省各县市ES供给和需求均存在明显的空间分异特征,且各评价单元匹配关系较差,其中空间关系表现出明显的供需冷热点空间错位特征,数量匹配一致性也较差。基于评估结果,将陕西省划分五类生态建设区域,并针对各区域供需特征及匹配关系,从生态、产业、人口等方面针对性地提出建设与管理措施。     

基于特征的时间序列聚类方法研究进展

时间序列聚类可以根据相似性将对象集分为不同的组, 从而反映出同组对象的相似性特征和不同组对象之间的差异特征。当序列维度较高时, 传统的时间序列聚类方法容易受噪声影响, 难以定义合适的相似性度量, 聚类结果往往意义不明确。当数据有缺失或不等长时, 聚类方法也难以实施。基于上述问题, 一些学者提出了基于特征的时间序列聚类方法, 不仅可以解决上述问题, 还可以发现序列本质特征的相似性。本文根据时间序列的不同特征, 综述了基于特征的时间序列聚类方法的研究进展, 并进行了分析和评述;最后对未来研究进行了展望。     

Visual analytics of delays and interaction in movement data

The analysis of interaction between movement trajectories is of interest for various domains when movement of multiple objects is concerned. Interaction often includes a delayed response, making it difficult to detect interaction with current methods that compare movement at specific time intervals. We propose analyses and visualizations, on a local and global scale, of delayed movement responses, where an action is followed by a reaction over time, on trajectories recorded simultaneously. We developed a novel approach to compute the global delay in subquadratic time using a fast Fourier transform (FFT). Central to our local analysis of delays is the computation of a matching between the trajectories in a so-called delay space. It encodes the similarities between all pairs of points of the trajectories. In the visualization, the edges of the matching are bundled into patches, such that shape and color of a patch help to encode changes in an interaction pattern. To evaluate our approach experimentally, we have implemented it as a prototype visual analytics tool and have applied the tool on three bidimensional data sets. For this we used various measures to compute the delay space, including the directional distance, a new similarity measure, which captures more complex interactions by combining directional and spatial characteristics. We compare matchings of various methods computing similarity between trajectories. We also compare various procedures to compute the matching in the delay space, specifically the Fréchet distance, dynamic time warping (DTW), and edit distance (ED). Finally, we demonstrate how to validate the consistency of pairwise matchings by computing matchings between more than two trajectories.     

遥感影像纹理分析方法研究

影像纹理是遥感影像中的重要信息,原始的光谱信息加上纹理信息可以提高影像的精确性。作为提高影像分类精度的重要方法——纹理分析,合理有效地使用纹理分析方法至关重要。不同的纹理分析方法,不同程度的提高影像分类的精度。目前对影像进行纹理分析的方法主要有：统计方法、结构方法和谱方法3类。分别就3种方法的研究进展、应用情况进行了阐述,最后对影像纹理分析方法3种模式对比研究。     

湖南省经济增长的动力机制与潜在问题分析

通过对湖南在改革开放20年以来所取得的经济增长成果的分析，探讨其经济波动性及其结构矛盾，对开放程度、使用外资额、企业固定资产投资额、工业效率、产业结构、人口规模等多方经济增长的动力机制，采用因子分析法等多种计量手段，分析湖南省经济增长的主要推动因素，揭示湖南省经济增长方式的特点和存在的问题，并提出了相应的对策。     

A comparison of geometric approaches to assessing spatial similarity for GIR

This research compares the geographic information retrieval (GIR) performance of a set of logistic regression models with those of five non‐probabilistic methods that compute a spatial similarity score for a query–document pair. All methods are applied to a test collection of queries and documents indexed spatially by two convex conservative geometric approximations: the minimum bounding box (MBB) and the convex hull. In the comparison, the tested logistic regression models outperform, in terms of standard information retrieval recall and precision measures, all of the non‐probabilistic methods. The retrieval performance achieved by the logistic regression models on MBB approximations is similar to that achieved by the use of the non‐probabilistic methods on convex hulls. Although these results are valid only for the test collection used in this study, they suggest that a logistic regression approach to GIR provides an alternative to the use of higher‐quality geometric representations that are more difficult to obtain, implement, and process. Additionally, this research demonstrates the ability of a probabilistic approach to effectively incorporate information about geographic context in the spatial ranking process.     

Assessment of Experimental Semivariogram Uncertainty in the Presence of a Polynomial Drift

Natural Resources Research - The semivariogram, which measures the spatial variability between experimental data, is generally used as a structural input in all two-point geostatistical procedures....     

桂西山地灾害的监测、预测及其对策

广西百色市是自然灾害频发的地区,降雨是激发山地灾害的关键因素。通过收集大量的地质灾害资料和气象资料,运用天气学、数值预报产品、MOS法等,结合卫星探测资料,建立各种地理环境和地质特征条件下山地灾害预警的气象模型和各种灾害等级的预警指标,并就山地灾害的监测与对策提出了一些建议和措施。     

CHARACTERISTICS OF NATURAL CONTENTS OF CHEMICAL ELEMENTS IN SOILS OF KARAKORUM-WEST KUNLUN MOUNTAIN REGION

I.ASurveyofNaturalConditionsKarakon1l1i-WestKul1l1l11Mtsissituatedi11thel1orthwesternpartoftheQinghai-Xizang(Tibetan)Plateau.Therearel1igl11llountains,deepandnarrowgorqe5.brondplateausandothercomplicatedlandforms.Characteristicsoflal1dfor1115nreaccountablefortl1eforl11atio11ofvario[1sverticaldistributiol1ofsoilspectrun1.1nthisrcgiol1,theclimatcisf;lgidaiidd1:Yi4it1ilitt1eprecipitatioi1.Gc,,c,d11,.pl'ecipitatio11i11plainareaatfootofthemountainsislessthanlOOmmbutitchangesalongwttl1variatio…     

基于临近相似性考虑的犯罪热点密度图预测准确性比较——以DP半岛街头抢劫犯罪为例

在无时空考虑的密度估计算法基础上,分别加入了案件点之间的时间临近相似性、空间临近相似性和时空临近相似性的考虑,利用DP半岛2006~2007年的街头抢劫犯罪数据为基础计算无时空临近相似性、时间临近相似性、空间临近相似性和时空临近相似性4种不同算法所得到的犯罪热点图,并以之预测2008年的街头抢劫。通过Natural breaks（Jenks）分级方法和等比例面积选取两种方式来划定热点区域进行预测并进行PAI指数得分比较,结果表明时空临近相似性的密度估计算方法在犯罪预测的优势比较显著。     

南极磷虾渔业近况与趋势分析

南极周边海域蕴藏着丰富的南极磷虾资源,其开发潜力受到世界各国的关注。为此,本研究基于南极海洋生物资源养护委员会(CCAMLR)统计数据分析了近几年南极磷虾渔业国家发展状况,并研究了南极磷虾渔业捕捞结构的变化特点。结果发现:(1)受捕捞技术及装备的限制,南极磷虾传统渔业国家——波兰、日本及乌克兰等正逐渐淡出开发行列;(2)随着挪威、中国及智利等新兴国家的加入,南极磷虾入渔船舶和渔业产量呈上升趋势;(3)南极磷虾全年均有生产,其中3—9月份渔获产量占总产量的70%—90%;(4)受综合环境因素和新的渔业管理措施影响,CCAMLR 48.1、48.2和48.3小区渔获产量年间波动变大,渔场选择难度增大;(5)传统的大规模科学调查模式已不适应该资源变化与渔业管理的要求,科学性渔业调查将成为今后南极磷虾资源调查与评估的重要补充。     

CLASSIFICATION OF MASS SPECTRA

In order to investigate correlations between the functionality of compounds and the classification of theirmass spectra,low-resolution spectra of monofunctional compounds have been classified by foursupervised classification methods.The new classes are characterized by structural features and thecorrelation between functionality and classification is explained by fragmentation rules.Systematicmisclassifications show that low-resolution mass spectra alone are not suitable for reliable identificationof functionality.