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101.
102.
针对实际生产需要,探讨利用计算机实现化探设计点位坐标提取和填写样品编号,重点介绍用VBA编程填写样品编号。这里还介绍了VBA语言及主要函数功能、程序流程及主要程序编码。通过实际应用表明,该程序流程合理、过程简单、运行速度快,有效改善了野外生产的精度及效率。 相似文献
103.
J. Bouchez F. Métivier M. Lupker L. Maurice M. Perez J. Gaillardet C. France‐Lanord 《水文研究》2011,25(5):778-794
Large rivers have been previously shown to be vertically heterogeneous in terms of suspended particulate matter (SPM) concentration, as a result of sorting of suspended solids. Therefore, the spatial distribution of suspended sediments within the river section has to be known to assess the riverine sedimentary flux. Numerous studies have focused on the vertical distribution of SPM in a river channel from a theoretical or experimental perspective, but only a few were conducted so far on very large rivers. Moreover, a technique for the prediction of depth‐integrated suspended sediment fluxes in very large rivers based on sediment transport dynamics has not yet been proposed. We sampled river water along depth following several vertical profiles, at four locations on the Amazon River and its main tributaries and at two distinct water stages. Depending on the vertical profile, a one‐ to fivefold increase in SPM concentration is observed from river channel surface to bottom, which has a significant impact on the ‘depth‐averaged’ SPM concentration. For each cross section, a so‐called Rouse profile quantitatively accounts for the trend of SPM concentration increase with depth, and a representative Rouse number can be measured for each cross section. However, the prediction of this Rouse number would require the knowledge of the settling velocity of particles, which is dependent on the state of aggregation affecting particles within the river. We demonstrate that in the Amazon River, particle aggregation significantly influences the Rouse number and renders its determination impossible from grain‐size distribution data obtained in the lab. However, in each cross section, the Rouse profile obtained from the fit of the data can serve as a basis to model, at first order, the SPM concentration at any position in the river cross section. This approach, combined with acoustic Doppler current profiler (ADCP) water velocity transects, allows us to accurately estimate the depth‐integrated instantaneous sediment flux. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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105.
For decades, stochastic modellers have used computerized random number generators to produce random numeric sequences fitting a specified statistical distribution. Unfortunately, none of the random number generators we tested satisfactorily produced the target distribution. The result is generated distributions whose mean even diverges from the mean used to generate them, regardless of the length of run. Non‐uniform distributions from short sequences of random numbers are a major problem in stochastic climate generation, because truly uniform distributions are required to produce the intended climate parameter distributions. In order to ensure generation of a representative climate with the stochastic weather generator CLIGEN within a 30‐year run, we tested the climate output resulting from various random number generators. The resulting distributions of climate parameters showed significant departures from the target distributions in all cases. We traced this failure back to the uniform random number generators themselves. This paper proposes a quality control approach to select only those numbers that conform to the expected distribution being retained for subsequent use. The approach is based on goodness‐of‐fit analysis applied to the random numbers generated. Normally distributed deviates are further tested with confidence interval tests on their means and standard deviations. The positive effect of the new approach on the climate characteristics generated and the subsequent deterministic process‐based hydrology and soil erosion modelling are illustrated for four climatologically diverse sites. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
106.
Random variable simulation has been applied to many applications in hydrological modelling, flood risk analysis, environmental impact assessment, etc. However, computer codes for simulation of distributions commonly used in hydrological frequency analysis are not available in most software libraries. This paper presents a frequency‐factor‐based method for random number generation of five distributions (normal, log–normal, extreme‐value type I, Pearson type III and log‐Pearson type III) commonly used in hydrological frequency analysis. The proposed method is shown to produce random numbers of desired distributions through three means of validation: (1) graphical comparison of cumulative distribution functions (CDFs) and empirical CDFs derived from generated data; (2) properties of estimated parameters; (3) type I error of goodness‐of‐fit test. An advantage of the method is that it does not require CDF inversion, and frequency factors of the five commonly used distributions involves only the standard normal deviate. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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108.
针对多个县(市)、区土地调查文字材料将1:100万图号中的行、列号用错而产生严重缺陷的事实,本人认真学习了"国家基本比例尺地形图分幅和编号"的基础知识,并总结归纳出简易的快速判断正误的方法,以杜绝类似差错的发生. 相似文献
109.
Multi-agent Blind Model and Its Application to Regional Eco-environmental Quality Assessment 总被引:3,自引:3,他引:0
LI Ruzhong 《中国地理科学(英文版)》2006,16(3):249-254
1 Introduction Eco-environmental quality assessment is an activity that is affected by man-made factors. As other environmental systems, regional eco-environment is also a complicated and uncertain system (Wu et al., 2005). Owing to these reasons, people may produce a style of subjective un- certainty in mind in evaluating such system (Liu et al. 1999a; Wu et al., 2004). According to unascertained mathematics (Liu et al., 1997; Liu et al., 1999b), we know that this kind of subjective uncerta… 相似文献
110.
本文构造了一种快速数论变换算法,该算法是一种以数论为基础,有效高速的数论变换算法,并且这种算法易于在计算机上实现。 相似文献