Modelling the long-term distribution of significant wave height with the Beta and Gamma models     

J. A. Ferreira  C. Guedes Soares 《Ocean Engineering》1999,26(8):185

The paper suggests modelling the long-term distribution of significant wave height with the Gamma, Beta of the first and second kind models. The three models are interrelated, flexible and cover the three different tail types of Extreme Value Theory. They can be used simultaneously as a means of assessing the uncertainty effects that result from choosing equally plausible models with different tail types. This procedure is intended for those applications that require the long-term distribution of significant wave height as input rather than the prediction of extreme values. The models are fitted to some significant wave data as an illustration. Details about maximum likelihood estimation are given in A.  相似文献   

测量极值问题的经验解式--兼论绝对和极小问题   总被引：4，自引：0，他引：4  

周江文 《测绘学报》1999,28(1):11-14

测量上有许多极值问题,如各种准则下的平差,权的最优分配,网的优化方案等,多可归于线性极值问题,且多不适用寻常数学解法。但同型问题往往已经作过多次解算。因此本文以单纯形法为主,强调利用已有经验,直接逼近优解,或经少数次迭进达到优解,然后极值条件加以验证。为此文中着重提出通用解式及优解条件,期能得出优解公式,有相当的适用范围。  相似文献   

位置不确定性与属性不确定性的场模型   总被引：23，自引：2，他引：21  

张景雄  杜道生 《测绘学报》1999,28(3):244-250

不确定性是自地理信息系统发展与应用以来一个引起关注的课题。位置不确定性与属性不确定常常不加区分地被看作是可以单个讨论的问题。本文将借助场的概念和模型使二者得以统一的描述和分析;对于明确定义的离散目标,二者虽然可分别讨论,但却在数学上有着联合的基础;对于非明确定义的地理现象,二者以连续体的形式而存在,位置不确定性可以作为属性不确定性的空间映射而提取出来。  相似文献   

相对湿度对大气气溶胶粒子短波辐射特性的影响   总被引：25，自引：2，他引：23  

杨军  李子华  黄世鸿 《大气科学》1999,23(2):239-247

利用Mie散射原理和重庆实测气溶胶资料,详细计算了边界层内单个气溶胶粒子的光学特性参量,气溶胶粒子群体的散射、吸收、消光系数及不对称因子、散射比、光学厚度;进而采用二流近似和累加法计算了边界层内太阳短波辐射增温率。目的在于研究相对湿度对以上各特性参量的影响。结果表明,相对湿度在65%～95%之间变化时,对气溶胶粒子群体光学特性参数和太阳增温率的影响在量级上可与气溶胶粒子浓度成倍变化的影响相比拟。  相似文献   

超大型铜镍硫化物矿床研究进展   总被引：4，自引：0，他引：4  

范育新  张铭杰 《甘肃地质》1999,8(2):47-52

超大型铜镍硫化物矿床不仅赋存有巨大的铂族贵金属资源,而且赋存有非常重要的深源信息,对其成矿理论的多学科综合研究具有重要的理论和实际意义。通过对超大型铜镍硫化物矿床的产出特征、时空分布、构造环境、控矿条件、母岩浆系列、成矿机理等研究现状的总结,认为以下几方面研究具有较大潜力：（１）矿床成因;（２）通过构造—流体—岩浆—成矿动力学综合研究,揭示成矿机制与全球变化的内在关系;（３）元古宙板块构造演化与超大型矿床形成的关系。  相似文献   

关于提高铜陵地区地质找矿的几点认识   总被引：1，自引：0，他引：1  

夏元法 《安徽地质》1999,(2)

铜陵地区虽然矿产资源丰富,成矿条件良好,但目前找矿的难度越来越大。笔者认为,要提高铜陵地区地质找矿的效果,就要根据本区的成矿规律,开展综合地质找矿,要进一步研究各矿田（床）的地质特征,继续提高铜陵地区的地质研究程度,充分运用现代成矿学新理论指导找矿,并大胆的用探矿工程加以验证。  相似文献   

A political-cultural map of Europe. Family structures and the origins of differences between national political cultures in the European Union     

Virginie Mamadouh 《GeoJournal》1999,47(3):477-486

Differences between the national political cultures of the European states are puzzling. They are too often taken for granted or treated as an elusive explanation for residual differences that can not be accounted for in comparative politics. Here they are put at the core of a comparative analysis. This article explores the origins of differences between national political cultures. It deals with national political cultures from the perspective of Cultural Theory or grid-group analysis. A national political culture is conceived as a ‘conversation’ between subcultures associated to national political institutions and practices (and not as an aggregated pattern of individual orientations toward political objects). National political cultures can be characterised on the basis of ideal typical patterns of relations between the basic cultures or rationalities distinguished by Cultural Theory. After an assessment of the differences between the national political cultures of the Member States of the European Union, the paper considers traditional family structures as possible sources of differentiation, elaborating upon the work of the French political historian Emmanuel Todd who has documented the correspondence between the geography of traditional family structures and the geography of ideologies in Europe. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

A watershed on the Rhine: Changing approaches to international environmental cooperation     

Marco Verweij 《GeoJournal》1999,47(3):453-461

Since the 1950s, the governments of the riparian countries of the Rhine have attempted to protect the ecosystems of the river basin through international cooperation. Before 1987, their relations were unproductive and antagonistic. International programs for the protection of Rhine were far less effective than domestic policies. From 1987 onwards, international cooperation on the protection of the Rhine has been exemplary, and has led the way in domestic and international water protection policies. Many existing frameworks of international relations are not able to offer an adequate account of this wholesale change. In this article, an attempt is undertaken with the help of grid-group theory. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

水压致裂法地应力测量若干问题的探讨   总被引：4，自引：0，他引：4  

刘允芳  刘元坤 《地震研究》1999,22(3):265-272

在深层地应力测量中,水压致裂法是最有效的测量方法。本探讨了该方法的几个关键性问题,例如压裂特征参数的取值,三维地应力测量,压裂缝的方向,破裂准则和钻孔轴向秒是主应力的一个方向等问题。  相似文献   

Analysis of reservoir water quality using fuzzy synthetic evaluation   总被引：12，自引：0，他引：12  

R.-S. Lu  S.-L. Lo  J.-Y. Hu 《Stochastic Environmental Research and Risk Assessment (SERRA)》1999,13(5):327-336

A general methodology for fuzzy synthetic evaluation is developed and illustrated with a case study of trophic status assessment for Fei-Tsui Reservoir in Taiwan. The historical data base was collected from the management agency of Fei-Tsui Reservoir from 1987 to 1996. In fuzzy synthetic evaluation, the classification is determined by a matrix operation of the weighted vector with the fuzzy evaluation matrix. After all individual membership functions of evaluated factors have been determined, the fuzzy evaluation matrix can be established. The weighted vector is determined by the analytic hierarchy process method (AHP). The results of this investigation show that the long-term change of water quality and the overturn phenomena cannot be observed with the Carlson index from 1987 to 1992 but is expressed by fuzzy synthetic evaluation. Fuzzy synthetic evaluation is better suited than the Carlson index to rating the trophic status of self-sustaining lakes. Interpretation of the results can provide valuable information to decision makers and aid reservoir management.  相似文献