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ＴｈｅｏｂｓｅｒｖａｔｉｏｎａｎｄｉｎｔｅｒｐｒｅｔａｔｉｏｎｏｆｇｅｏｍａｇｎｅｔｉｃｖａｒｉａｔｉｏｎｓｉｎａｓｍａｌａｒｅａｏｆＨａｉｎａｎＰｒｏｖｉｎｃｅ，ＣｈｉｎａＧＵＯＨＵＡＦＡＮ１）（范国华）ＴＯＮＧＱＩＹＡＯ１）（姚同起）ＺＵＯ... 相似文献
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Abstract Various theoretical expressions are presented for determining risk in water resources systems design based on floods modelled by dependent processes. The effect of dependence on the simple risks involved in any engineering design is investigated on the basis of the lag-one Markov process. Asymptotically dependent process formulations reduce to independent case solutions that are already available in the literature. It is shown that a design risk value can be determined if the expected project life, serial correlation coefficient and simple risk are known. Necessary procedures and tables are presented for risk calculations when the variables concerned are serially correlated. 相似文献
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The hydrochemical background and the specific features of pollution of geological environmental components by hydrocarbons and chemical components in the industrial sites of oil and gas fields is characterized for two types of natural-anthropogenic environments with different hydrogeological conditions. A methodology is proposed for comprehensive environmental-hydrogeological studies for the development of information support for the assessment of the hazard and risk for the environmental conditions, organization of complex environmental monitoring, and projecting of measures for protection of water resources. 相似文献
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用人工神经网络进行空间不完备数据的插补 总被引：2，自引：0，他引：2
在地学研究中,特别是区域性资料处理过程中,常常遇到“不完备数据”的问题,即所谓的“数据不全”。在尽量减小估计误差的条件下对缺失数据进行预测或插补,对于充分利用历史资料和已知信息,提高预测质量具有重要意义。利用径向基人工神经网络(RBF)同时具有自组织神经网络和回归网络的优点,可以对缺失数据进行预测。实际区域地球化学数据处理的结果表明,RBF网络对空间不完备数据的建模和预测具有优异的效果。 相似文献
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B. G. ANDERSEN F. BÖEN A. RASMUSSEN P. N. VALLEVIK 《Boreas: An International Journal of Quaternary Research》1979,8(2):199-201
Six successive zones with distinctive marginal moraines are recognized. Based on radiocarbon dates the ages of the three oldest zones are believed to be: older than 11,100 years B.P. (Vasdal event), about 10,900 B.P. (Glomfjord-Straumöy events), and between 10,400 and 9500 B.P. (Skjerstad event). The three youngest zones are Preboreal. Corresponding marine sediments, shorelines, glaciation limits and other glacial features are described. 相似文献
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Abstract Using an approach similar to the biological processes of natural selection and evolution, the genetic algorithm (GA) is a nonconventional optimum search technique. Genetic algorithms have the ability to search large and complex decision spaces and handle nonconvexities. In this paper, the GA is applied for solving the optimum classification of rainy and non-rainy day occurrences based on vertical velocity, dewpoint depression, temperature and humidity data. The problem involves finding optimum classification based on known data, training the future prediction system and then making reliable predictions for rainfall occurrences which have significance in agricultural, transportation, water resources and tourism activities. Various statistical approaches require restrictive assumptions such as stationarity, homogeneity and normal probability distribution of the hydrological variables concerned. The GAs do not require any of these assumptions in their applications. The GA approach for the occurrence classifications and predictions is presented in steps and then the application of the methodology is shown for precipitation occurrence (non-occurrence) data. It has been shown that GAs give better results than classical approaches such as discriminant analysis. The application of the methodology is presented independently for the precipitation event occurrences and forecasting at the Lake Van station in eastern Turkey. Finally, the amounts of precipitation are predicted with a model similar to a third order Markov model whose parameters are estimated by the GA technique. 相似文献