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排序方式: 共有792条查询结果,搜索用时 31 毫秒
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The objective of this study is to demonstrate that the channel flow routing techniques used in the Soil and Water Assessment Tool (SWAT) can be sometimes inappropriate for runoff simulation in small basins. Simulated hydrographs have a tendency to underestimate peak flows or may send a false signal during the recession periods when SWAT is applied to the Mihocheon Basin in South Korea. This was particularly evident for sub‐basins that had a short travel time of much less than a day. In order to enhance the channel routing module in SWAT, an alternative routing technique in which Manning relationship is combined with a simple channel reach continuity equation is proposed in the present study. The advantage of the proposed routing technique is that parameters are readily available from channel morphological data and that it is applicable to small basins. Through simulations of specific events, this routing module that is incorporated into SWAT is almost free from instability errors and produces realistic flow depths and velocities unlike the original version of SWAT with Muskingum method. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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本文介绍一种最近由作者在美国研制的,由计算机产生等距离区域分界线的程序及其数据结构,同时给出初步的试验结果。 相似文献
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B. M. Troutman M. R. Karlinger 《Stochastic Environmental Research and Risk Assessment (SERRA)》1988,2(1):73-78
The instantaneous unit hydrograph for a channel network under general linear routing and conditioned on the network magnitude,N, tends asymptotically, asN grows large, to a Rayleigh probability density function. This behavior is identical to that of the width function of the network, and is proven under the assumption that the network link configuration is topologically random and the link hydraulic and geometric properties are independent and identically distributed random variables. The asymptotic distribution depends only on a scale factor,
, where is a mean link wave travel time. 相似文献
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Gordon Kaufman 《Natural Resources Research》1994,3(4):304-314
The relative efficiencies of alternative geometric patterns of both discrete borehole and continuous grid line search have been extensively discussed in the mathematical geology literature. However, an equally important problem has received virtually no attention: How to use a sample of properties of geologic anomalies detected by grid line search of a region to estimate systematically both the number and size distribution of geologic anomalies missed by the search. We show how estimation methods developed in the sample survey design literature can be adapted to this problem, and we apply these methods to data describing 94 anomalies identified by a seismic reconnaissance survey. 相似文献
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The steepest descent(or ascent)search is employed for finding optimum diffusion coefficients in T42L9Gmodel,with a view to improving the model's computational stability or prediction accuracy.The method of thesteepest descent search is first described,in which the golden section search is chosen as the fundamental one-dimensional search used in the multi-dimentional steepest descent search,and then the optimization of the dif-fusion coefficients is described. 相似文献
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基于启发式图搜索的遥感影像道路半自动提取 总被引:10,自引:2,他引:10
启发式图搜索法用于线状目标识别的原理是:用图结构表示边缘点和边缘段,根据启发函数计算顶点权值,在图的路径上建立相应的代价函数,通过在图中搜索对应的最小代价的通道以找到最优路径。图搜索法是一种全局最优方法,它在受噪声影响较大时效果仍然较好。文中使用了启发式图搜索法(A*算法)实现了道路的半自动跟踪。它的基本思路是:首先利用自适应平滑滤波算子进行道路信息增强,然后对传统的道路数学模型进行了进一步的扩展,突出了对道路几何特性和辐射特性的描述,并依此构建图搜索的代价函数,实现了基于启发式图搜索法A*算法的道路半自动跟踪。经实验证明,该方法进行遥感影像的道路半自动提取效果较好。 相似文献