未来气候变化对7种荒漠植物分布的潜在影响   总被引：1，自引：0，他引：1  

吴建国 《干旱区地理》2011,34(1):70-85

利用CART(classification and regression tree,分类和回归树)模型,采用A2和B2气候情景,分析了气候变化对百花蒿、红砂、灌木亚菊、灌木小甘菊、戈壁藜、瓣鳞花和白梭梭分布范围及空间格局的影响.结果显示:气候变化下,就目前适宜分布范围,这些植物都呈现缩小趋势;就新适宜及总适宜分布范围,...  相似文献   

Remote Sensing and GIS Application to Superlarge Mineral Deposits Prediction in Western Slope of Great Xing'an Mountains, China     

Chen Shengbo 《东北亚地学研究》2000,(1)

1　ＩｎｔｒｏｄｕｃｔｉｏｎＡｓｏｎｅｏｆｔｈｅｔｗｅｌｖｅｆｏｒｗａｒｄｐｒｏｂｌｅｍｓｆｏｒｔｈｅ1990’ｓｅａｒｔｈｓｃｉｅｎｃｅｓ ,ｓｕｐｅｒｌａｒｇｅｍｉｎｅｒａｌｄｅｐｏｓｉｔｓｈａｖｅｍｅｔａｌｌｏｇｅｎｅｔｉｃ ｐｒｅｆｅｒｅｎｔｉａｌｉｔｙ  相似文献   

Study on the Seismogeny and Occurrence of Earthquakes by Using Pattern Dynamics     

Lan Congxin  Xu Ping 《中国地震研究》2000,14(3):235-245

The mesoscopic damage dynamics and damage evolution have been applied to probe theevolutional process induced catastrophe in the earthquake activity.It is a new method.In thispaper,a brief introduction of the basic principle about damage dynamics and evolution ismade.At the same time,using the theory of the pattern dynamics we studied all earthquakes(M_L≥5.0)which occurred along Zhangjiakou-Bohai Sea earthquake belt in the capitalregion.The result indicates that the preparation and happening of the real earthquakes andthe theory are consistent.There are two kinds of evolutional model according to the finalstate,namely,global stability model(GS)and evolution induced catastrophe model(EIC).The two models haven’t evident boundary.The transitional zone exhibits the indeterminacyof the seismic process and the effect of the random variation.This research proposed newapproaches for earthquake prediction.  相似文献   

SHORT COMMUNICATION STRUCTURE MODELLING AND DISCRIMINATION OF CATALAN WHITE WINES     

M.S.LARRECHI  M.R.FRANQUES  M.FERRE  F.X.RIUS 《地理学报(英文版)》1988,(Z1)

Cluster analysis has been applied to characterize the group structures of four sets of Catalan white wines(Conca de Barberà),Camp de Tarragona,Terra Alta and Ribera-Falset)on the basis of eleven classicaloenological parameters and seven micro and trace metallic constituents considered to be relativelyinsensitive to cultural practices.In spite of the vintage variation and the lack of a clear varietaldifferentiation among the wines,each region could be individually characterized.The application ofsupervised pattern recognition methods has allowed regional assignment of unknown samples with aprediction rate higher than 95%.Several metal ions(such as calcium,strontium, zinc and magnesium)and a few classical parameters(such as ethanol content and the sum of malic and lactic acid contents)have been found to be relevant for a correct classification.ALLOC and KNN classification methodscombined with LDA have been proven useful with the present data set,although their performance wasnot superior to that of LDA and SIMCA.  相似文献   

ASSIGNING THE ORIGIN OF CATALAN MEDIEVAL STAINED GLASSES BY PATTERN RECOGNITION METHODS OF X-RAY FLUORESCENCE DATA     

G.RAURET  E.CASASSAS  M.BAUCELLS  M.S.LARRECHI  F.X.RIUS 《地理学报(英文版)》1988,(Z1)

Thirteen different components of six samples belonging to stained medieval glass windows and twelvesimilar samples found in the archives of Girona Cathedral(Catalonia,Spain)during restoration workwere determined by x-ray fluorescence analysis.The use of display and cluster analysis methods,principal components analysis,non-linear mapping,minimal spanning tree and agglomerativehierarchical clustering applied to these results,together with those of nine samples from the samecathedral previously studied,showed the presence of a quite compact cluster formed by the soda-typesamples,indicating a probably similar origin and confirming the peculiarities of this Mediterranean area.The potash-type glasses were highly scattered with little similarity among them,suggesting a likelydifferent source of these samples.The twelve glasses of strictly unknown origin were found to have a highdegree of resemblance to the samples of known context,thus excluding the possibility of them beingsamples made in a very different age or site.Three of them were classified into the same group as thewell-defined soda-type glasses by the pattern recognition method SIMCA.  相似文献   

THE EFFECT OF MISLABELED SAMPLES ON THE PERFORMANCE OF THE LINEAR LEARNING MACHINE     

BARRY K.LAVINE ANTHONY J.I.WARD JIAN HWA HAN Department of Chemistry  Clarkson University  Potsdam  NY  U.S.A.ROY-KEITH SMITH Georgia Department of Agriculture  Capitol Square  Atlant  GA  U.S.A.ORLEY R.TAYLOR Department of Entomology  University of Kansas  Lawrence  KS  U.S.A. 《地理学报(英文版)》1990,(1)

Over the past 15 years the linear learning machine has been applied to a large number of chemicalproblems.The learning machine approach is conceptually simple and does not require knowledge aboutthe statistical distribution of the data.However,there are problems associated with this approach.Oneproblem which has not been investigated is the influence of mislabeled samples on the positioning of thehyerplane in feature space.If a few samples in a data set are incorrectly tagged prior to training(i.e.thesamples are labeled as members of class 2 even though they are actually members of class 1),it is stilIpossible using the linear learning machine to achieve a classification success rate of 100% for the trainingset.However,unfavorable results will be obtained for the prediction set.The magnitude of this effect andits potential implications regarding the proper use of the linear learning machine are discussed.  相似文献   

辽南不同岩性地区地下水动态研究   总被引：2，自引：1，他引：1  

刘庆书  许劲松 《地理研究》1991,10(3):23-29

本文从影响辽南地区地下水动态因素,主要从岩性、蓄水构造的制约因素,探讨分析了辽南不同岩性地带的地下水动态特点,划分了基本类型,揭示其规律性。为因地因时制宜地充分开发,合理有效利用珍贵的地下水资源提供科学依据。  相似文献   

全球铜矿资源储量格局   总被引：1，自引：0，他引：1  

王威 《国土资源情报》2014,(6):38-41

本文通过对铜矿资源国的储量的整理和分析,得到全球铜矿资源储量格局,利用储采比进行铜矿资源保障程度论证,并结合矿产资源勘查特点,对不同资源储量国提出不同的工作重点,从而有针对性地开展铜矿资源的境外合作。  相似文献   

中高纬度大气遥相关动力学及其对东亚冬季气候影响的研究进展   总被引：6，自引：1，他引：5       下载免费PDF全文

TAN Benkui  CHEN Wen 《Acta Meteorologica Sinica》2014,28(5):780-802

北半球热带外大气存在多种形态的大气遥相关。按其空间结构,可以分为两类：（1）异常中心为南北分布的偶极子型（例如北大西洋涛动、北太平洋涛动）;（2）异常中心呈波列型（例如北太平洋/北美型遥相关、欧亚型遥相关）。这些遥相关活动及其变异,不仅对遥相关控制的地区,而且对与遥相关相距很远的地区的天气和气候也产生影响。研究大气遥相关的形成机理及其天气气候影响,是进行短期气候预测的基础。近十多年来北半球中高纬度的大气遥相关动力学研究取得很大进展,在此对一些主要进展进行总结,特别关注影响中国天气、气候的大气遥相关及其影响机理方面的研究进展。  相似文献   

U.K.USAGE OF CHEMOMETRICS AND ARTIFICIAL INTELLIGENCE IN QSAR ANALYSIS     

V.S.ROSE R.M.HYDE Department of Physical Sciences  Wellcome Research Laboratories  South Eden Park Ro  Beckenham  Kent BR BS  U.K.H.J.H.MACFIE AFRC Institute of Food Research  Reading Laboratory  Shinfiel  Reading RG AT  U.K. 《地理学报(英文版)》1990,(5)

A survey of members of the U.K.QSAR Discussion Group has been made to determine the extent ofuse and development of chemometric and artificial intelligence(AI)methods in the analysis ofmultivariate quantitative structure-activity relationship(QSAR)data in the U.K.Chemometric methodswere found to be well established in both industrial and educational establishments and there wassignificant method development occurring.AI methods were not employed to any great extent and thegeneral level of interest in these techniques was low compared to chemometric methods.A requirementfor more education in multivariate statistical methods and regression methods was indicated.A need fora user-friendly,comprehensive,commercially available multivariate statistical package containingmultivariate stability testing and regression diagnostic methods was identified.  相似文献