广西第三代1∶50万数字地质图特点及其意义     

张继淹 《南方国土资源》2000,(1)

文章扼要介绍了广西第三代 1∶5 0万数字地质图的主要内容、特点及编图新理论和新技术 ,并指出该项成果所具有的科学意义和实用价值。  相似文献   

Non-Darcian groundwater flow in leaky aquifers     

ZEKAI ŞEN 《水文科学杂志》2013,58(4):595-606

Abstract

A simplified method has been developed for solving leaky aquifer non-Darcian flow hydraulics. The principle of volumetric approach is combined with the confined-aquifer, time-dependent drawdown equation in an observation well. The groundwater flow in the leaky aquifer is assumed to obey a non-Darcian flow law of exponential type. The results are obtained in the form of type-curve expressions from which the necessary bundles of curves are drawn for a set of selective non-Darcian flow aquifer parameters. Although application of the methodology appears as rather limited but it provides a scientific contribution and extension of leaky aquifer theory towards nonlinear flow conditions. The methodology developed herein is applied to some actual field data from the eastern sedimentary basin in the Kingdom of Saudi Arabia.  相似文献   

条带开采地表沉陷预计参数的确定   总被引：1，自引：0，他引：1  

柴华彬  邹友峰 《测绘科学》2009,34(4)

概率积分法是条带开采地表移动和变形预计常用的方法,而概率积分法预计的精度取决于其预计参数的确定。以国内大量的条带开采实测资料为基础,应用相似理论对条带开采地表沉陷的相似现象进行了模糊聚类分析,计算出了条带开采地表沉陷预计参数。根据所得条带开采地表沉陷相似现象的分类及其地表沉陷预计参数,应用模式识别对待求条带开采地表沉陷预计参数进行了求取。工程实例表明,用模糊优化确定的预计参数进行条带开采地表移动和变形预计,其预计结果更加可靠、准确。  相似文献   

基于云理论、粗集和模糊神经网络的区域橡胶种植适宜度评估模型   总被引：1，自引：0，他引：1  

曹阳  宋伟东 《测绘科学》2009,34(6)

针对橡胶种植适宜性评估,基于云理论、粗集理论和模糊神经网络理论,提出了一种适宜度评估模型。该模型将转化的样本数据进行粗集简约,通过模糊神经网络得出评价因子的隶属函数,计算评价等级。研究结果表明,此模型能够科学、快速、准确地分析出橡胶种植最适宜区、适宜区、次适宜区和不适宜区。  相似文献   

模糊控制在直流变频空调器中的应用     

邓金强  王晓平 《成都信息工程学院学报》2004,19(4):490-495

从直流型变频空调器的特点及控制要求出发,提出了模糊控制系统的结构,讨论了直流变频空调器的模糊控制算法.对控制器的性能(主要是鲁棒性)进行了详细的分析,对所采用的模糊控制算法在Matlab平台下进行了仿真,作为比较同时给出了其他常用算法的仿真结果.  相似文献   

A fuzzy dynamic flood routing model for natural channels     

R. Gopakumar  P. P. Mujumdar 《水文研究》2009,23(12):1753-1767

A fuzzy dynamic flood routing model (FDFRM) for natural channels is presented, wherein the flood wave can be approximated to a monoclinal wave. This study is based on modification of an earlier published work by the same authors, where the nature of the wave was of gravity type. Momentum equation of the dynamic wave model is replaced by a fuzzy rule based model, while retaining the continuity equation in its complete form. Hence, the FDFRM gets rid of the assumptions associated with the momentum equation. Also, it overcomes the necessity of calculating friction slope (S_f) in flood routing and hence the associated uncertainties are eliminated. The fuzzy rule based model is developed on an equation for wave velocity, which is obtained in terms of discontinuities in the gradient of flow parameters. The channel reach is divided into a number of approximately uniform sub‐reaches. Training set required for development of the fuzzy rule based model for each sub‐reach is obtained from discharge‐area relationship at its mean section. For highly heterogeneous sub‐reaches, optimized fuzzy rule based models are obtained by means of a neuro‐fuzzy algorithm. For demonstration, the FDFRM is applied to flood routing problems in a fictitious channel with single uniform reach, in a fictitious channel with two uniform sub‐reaches and also in a natural channel with a number of approximately uniform sub‐reaches. It is observed that in cases of the fictitious channels, the FDFRM outputs match well with those of an implicit numerical model (INM), which solves the dynamic wave equations using an implicit numerical scheme. For the natural channel, the FDFRM outputs are comparable to those of the HEC‐RAS model. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

模糊神经网络在GPS高程转换中的应用   总被引：1，自引：1，他引：0  

方毅  雒卫民 《地理空间信息》2009,7(4):108-110

介绍了T-S模糊神经网络的基本原理以及如何确定GPS高程转换的模糊神经网络模型，并采用该模型对实测数据进行了计算分析。结果表明，模糊神经网络能够对小区域GPS高程做出比较准确定的拟合，从而能够为GPS高程转换提供一种较好的方法，能够满足实际工程需要。  相似文献   

New Methods of Fitting the Membership Function of Oceanic Water Masses   总被引：3，自引：1，他引：2  

LIFengqi XIEJun LIYao 《中国海洋大学学报(英文版)》2004,3(1):1-9

1　Introduction　Watermassanalysisisanimportantsubjectinphys icaloceanographystudies (PickardandEmery ,1 990 ;YeandLi,1 992 ) .Helland Hansenplottedin 1 91 6theT Scurve ,whichisafterwardsknownasoneoftheT Sdiagrams ,andsuggestedthatawatermasscanbedefinedby…  相似文献   

基于模糊Hopfield神经网络的大气降水粒子分类     

韦一  佘勇  王贤勤 《成都信息工程学院学报》2007,22(5):569-572

提出基于模糊Hopfield神经网络的大气降水粒子分类,它是通过计算样本间的模糊关系的相似程度,再加上Hopfield网络所特有的高稳定性,对大气降水粒子进行分类.通过对各降水粒子所对应雷达回波数据的分析,验证了方法的可行性.  相似文献   

Storm‐event rainfall–runoff modelling approach for ungauged sites in Taiwan     

Yu‐Chi Wang  Shien‐Tsung Chen  Pao‐Shan Yu  Tao‐Chang Yang 《水文研究》2008,22(21):4322-4330

This work develops a top‐down modelling approach for storm‐event rainfall–runoff model calibration at unmeasured sites in Taiwan. Twenty‐six storm events occurring in seven sub‐catchments in the Kao‐Ping River provided the analytical data set. Regional formulas for three important features of a streamflow hydrograph, i.e. time to peak, peak flow, and total runoff volume, were developed via the characteristics of storm event and catchment using multivariate regression analysis. Validation of the regional formulas demonstrates that they reasonably predict the three features of a streamflow hydrograph at ungauged sites. All of the sub‐catchments in the study area were then adopted as ungauged areas, and the three streamflow hydrograph features were calculated by the regional formulas and substituted into the fuzzy multi‐objective function for rainfall–runoff model calibration. Calibration results show that the proposed approach can effectively simulate the streamflow hydrographs at the ungauged sites. The simulated hydrographs more closely resemble observed hydrographs than hydrographs synthesized using the Soil Conservation Service (SCS) dimensionless unit hydrograph method, a conventional method for hydrograph estimation at ungauged sites in Taiwan. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献