共查询到19条相似文献，搜索用时 609 毫秒
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次生晕数据的对数正态泛克立格法研究及异常评价 总被引：2，自引：0，他引：2
首先介绍了对数正态泛克立格法的基本理论和方法,包括对数正态分布,三参数对数正态分布,求解估值(Z_v)~*所需的权系数λ_α.及求解漂移值(m_v)~*所需的权系数ρ_α的对数正态泛克立格方程组.其次,笔者应用对数正态泛克立格法探讨了华北某测区的次生晕数据、元素统计分布特征以及变异函数及结构分析.最后,给出测区估计结果,元素综合异常图,划分出5个异常区,并结合地质条件对异常进行了综合评价. 相似文献
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某些岩土参数的对数正态分布特征 总被引：1，自引：0，他引：1
本文试图说明服从对数正态分布岩土参数频率直方图的分布特征和在累积频率概率格约牙作正态检验及求取参数特征值的统计方法。使岩土参数的统计更合理。 相似文献
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粒度分析是一种精细的统计工作,其数据的观测与处理均以概率论和统计学为基础,粒度分析工作者必须掌握基本的概率论和统计学知识,并熟悉常用的数理统计方法。一、概率论与统计学基础 (一)在基本概念方面应掌握:随机变量、总体和个体、样本和样本容量、频数、频率和稳定频率、概率、统计分组、分布函数和分布参数等。对于岩矿粒度分析具有重要意义的分布函数有:正态分布(算术正态及对数正态)、罗森分布、单众值分布、多众 相似文献
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地球化学正态分布悖论 总被引：1，自引：0，他引：1
林存山 《物探化探计算技术》1994,16(4):288-293
１．化探中正态数据未必是正态地球化学特征的体现，正态可能是一种假象。２．用分布参数的偏度与峭度作为正态分布的检验准则而不伴随其它检验方法是不充分的。３．用对数变换将正偏数据正态化可能导致参数计算的明显不合理。４．总体分解方法可因人而异，结果是多样的使人迷惑的。５．将自变量和因变量正态化可实现最优回归预测的论点未必正确。这可通过分析或模拟得到确认。 相似文献
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本文依据矿床地质变量概率分布的不同类型将矿床分为正态分布型、Г分布型、对数正态分布型(简称之为正态型、Г型和对数正态型),并着重对Г型矿床展开了详细讨论。讨论了Г型矿床资源量的评估模型。提出Г分布中的参数p可作为表征Г型矿床成矿期次的数量指标。 相似文献
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正确区分不同期次、不同阶段形成的花岗岩体,尤其是在出露条件不好的情况下进行这种区分,是华南地区花岗岩深入研究的一个重要方面;对于找矿勘探工作也具有指导意义.用概率图方法可对所获得的大量数据资料统计分布上的多峰混合型总体进行筛分,估计分总体的统计参数.不同的混合型分布反映了不同的地质背景,对应于某些地质作用.不同期次、不同阶段形成的花岗岩中,某种化学成分的分布是服从正态或对数正态概率分布的.由于元素的地球化学特性,随着岩浆的演化,相应于每一期次或每一阶段的花岗岩体,其分布的均值、均方差是不同的.因此,将多次侵入的花岗岩体形成的复合型分布筛分成几个总体,则说明可能存在几次岩浆侵入.这是方法应用的着眼点. 相似文献
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本文根据川中某地１５０ｋｍ２范围内应用的７种放射性方法，在同一测点上获取的９个参数，共１９０２个测量数据，进行了统计分布特征研究。研究结果表明：７种放射性测量方法所获的原始数据具有３种统计分布类型──近似算术正态型、对数正态型、混合型。利用广义幂正态转换方法［１］将上述３种分布类型归结为一种分布──正态分布，获得了客观的区域背景值和异常下限值。为进一步的统计分析提供了一个较为合理的数学模型。 相似文献
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孟宪伟 《物探化探计算技术》1994,(1)
稳健克立格及其在１∶５万地球化学异常圈定方面的应用孟宪伟（中国科学院地球化学研究所）在１：５万地球化学测量域内不但有多母体地质体分布，而且还有多期成矿作用的叠加，因而元素的统计分布形式一般都不符合正态或对数正态分布，那么用稳健统计方法估计位置和尺度是... 相似文献
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广义极值分布频率曲线,也可采用均值、变差系数和偏态系数等三个统计参数来进行计算。通过建立离均系数表,可以方便地进行频率分析计算。现以澧水某站年最大流量系列为例,采用广义极值分布的适线法进行频率分析计算,成果表明广义极值分布具有一定适应性。 相似文献
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Jacques Rivoirard 《Mathematical Geology》1990,22(2):213-221
The term lognormal kriging does not correspond to a single well defined estimator. In fact, several types of lognormal estimators forin situ reserves are available, and this may cause confusion. These estimators are based on different assumptions—that is, different models. This paper presents a review of these estimators. 相似文献
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In an open pit mine, the selection of blocks for mill feed necessitates the use of a conditionally unbiased estimator not only to maximize profits, but also to predict precisely the grades at the mill. Estimation of blocks usually is done using a series of blasthole assays on a regular grid. In many instances, the blasthole grades show a lognormal-like distribution. This study examines an estimator based on the hypothesis of bilognormality between the true block grade and the estimate obtained using the blastholes. The properties of the estimator are established and the estimator is proven to be conditionally unbiased. It is almost as precise as the lognormal kriging estimator when the points are multilognormal. However, it is more precise than lognormal krigings when only univariate lognormality is present or when the distribution is not exactly lognormal. The estimator also is shown to be robust to errors in the specifications of the variogram model or of the expectation of Z. Contrary to lognormal krigings, the estimator does only a slight correction to the original estimate obtained using the blastholes assays. 相似文献
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Comparing the robustness of ordinary kriging and lognormal kriging: Outlier resistance 总被引：1，自引：0，他引：1
Ordinary kriging is well-known to be optimal when the data have a multivariate normal distribution (and if the variogram is known), whereas lognormal kriging presupposes the multivariate lognormality of the data. But in practice, real data never entirely satisfy these assumptions. In this article, the sensitivity of these two kriging estimators to departures from these assumptions and in particular, their resistance to outliers is considered. An outlier effect index designed to assess the effect of a single outlier on both estimators is proposed, which can be extended to other types of estimators. Although lognormal kriging is sensitive to slight variations in the sill of the variogram of the logs (i.e., their variance), it is not influenced by the estimate of the mean of the logs.This paper was presented at MGUS 87 Conference, Redwood City, California, 14 April 1987. 相似文献
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P. A. Dowd 《Mathematical Geology》1982,14(5):475-499
A theoretical study of the general case of the estimation of regionalized variables with a lognormal distribution is presented. The results of this study are compared to those obtained assuming conservation of lognormality. The numerical significance of the different solutions is illustrated by several simple examples. 相似文献
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A. Grassia 《Mathematical Geology》1982,14(4):321-330
Discovery sampling is a simple sampling inspection technique which has been used by internal auditors during the last 30 years. Occasionally it has found application in agricultural research. It will be shown that an amended version of this technique can be used in the sampling of orebodies for the presence of particles of a mineral such as gold, silver, uranite, and so forth. While with the classical Discovery sampling a simple discrete distribution (Multinomial, Poisson, etc.)is involved, in our case convolutions of a discrete (Poisson)and continuous distributions (gamma, lognormal)occur, because of the indirect procedure used in detecting the presence of the mineral in the orebody. Illustrative examples using two distributions of gold particles are given. 相似文献
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It is generally agreed that particle size distributions of sediments tend ideally to approximate the form of the lognormal probability law, but there is no single widely accepted explanation of how sedimentary processes generate the form of this law. Conceptually, and in its simplest form, sediment genesis involves the transformation of a parent rock mass into a particulate end product by processes that include size reduction and selection during weathering, transportation, and deposition. The many variables that operate simultaneously during this transformation can be shown to produce a distribution of particle sizes that approaches asymptotically the lognormal form when the effect of the variables is multiplicative. This was first shown by Kolmogorov (1941). Currently available models combine breakage and selection in differing degrees, but are similar in treating the processes as having multiplicative effects on particle sizes. The present paper, based on careful specification of the initial state, the nth breakage rule and the nth selection rule, leads to two stochastic models for particle breakage, and for both models the probability distributions of particle sizes are obtained. No attempt is made to apply these models to real world sedimentary processes, although this topic is touched upon in the closing remarks. 相似文献
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P. M. Adler 《Mathematical Geology》2001,33(1):63-93
A general analysis of electroosmotic phenomena is given for random porous media through which an electrolyte flows. A dimensional analysis demonstrates the crucial importance of the dimensionless coupling parameter a, which is usually very small when compared to 1; this suggests an expansion in terms of a and a numerical scheme that avoids the instabilities occurring in the direct solution. For media whose properties such as permeability are lognormally distributed, an analytical expression of the macroscopic coupling coefficients can be obtained when the fluctuations are small. Various results are provided for laminated media, correlated media, and stratified or fractured media. The influence of some macroscopic geometrical parameters is illustrated. 相似文献