共查询到18条相似文献，搜索用时 500 毫秒
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一种考虑权值非负约束的克立格算法 总被引：2，自引：0，他引：2
基于线性规划方法提出了一种考虑权值非负约束的克立格算法,该算法既利用了线性规划求解简便、快捷的优点,又克服了其它正克立格法计算工作量大以及受主观因素影响的缺点。 相似文献
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克立格估计邻域大小的确定方法 总被引：1，自引：0，他引：1
分析了以往地质统计学确定估计领域域时的不足,提出了克立格估计方差、均值权,真值与估计值之间线性表达式的斜率、真值与估计值的相关系数以及克立格估值中的负权样品数等可作为确定克立格估计领域域大小的关键参数,对于脉状脉体而言,除了考虑以上参数外,还应限制矿体厚度方向上的大小。 相似文献
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克立格法是地质统计学的一种基本方法，在非平稳物化探数据处理中经常用到泛克立格方法。在用泛克立格法处理实际问题中，要用大量的机时求解克立格方程组，本文提出一种新的解法，减少运算量５０％左右，大大提高了运算速度。 相似文献
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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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地质统计学方法在地下水水位估值中应用 总被引：7，自引：0，他引：7
对于许多区域水资源或水环境问题,地下水水流模拟往往要采用数值方法,需给出每个节点上初始水位值,以反映流场的初始状态。另外,地下水水位动态长期监测分析,需由观测点水位估计任一点的水位。文中阐述了地下水水位估值的地质统计学方法－泛克立格法原理,以河南省焦作市修武段地下水数值模拟分析区为例,分析了用一次、二次漂移的泛克立格方法模拟地下水初始流场的估值情况和对真实流场特征的反映情况。指出在进行区域地下水位 相似文献
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克立格方法在区域化探数据处理中的应用 总被引：1，自引：0，他引：1
针对克立格方法能表征变量空间结构特征 ,以团结沟金矿研究区的化探数据处理为例 ,讨论了一般多元统计方法、协同克立格方法和普通克立格方法在化探元素间的相关分析结果。协同克立格方法对原始数据进行估值得到的绝对误差的均值要比用其它方法得到的绝对误差的均值低 ,标准差也明显降低。相比之下 ,协同克立格方法在一定程度上较为优越 ,它提高了地质统计学的预测精度 ,缺点是计算工作量较大。 相似文献
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时空多元协同克立格的理论研究 总被引：11，自引：0，他引：11
本文结合地质统计学的最新成果,在空间协同区域化理论的基础上,对时空域中多元信息的协同克立格（ＳＴＣＯＫ）理论进行了较为详细的研究。主要研究内容有：（１）ＳＴＣＯＫ中的互变异函数与互协方差函数;（２）ＳＴＣＯＫ方程组及求解估值权因子的三种方法：①传统普通协同克立格法（ＳＴＴＯＣＯＫ）,②标准普通协同克立格法（ＳＴＳＯＣＯＫ）,③简单协同克立格法（ＳＴＳＣＯＫ）;（３）排列协同克立格（ＳＴＣＯＬＣＯＫ）;（４）指示协同克立格（ＳＴＩＫＣＯＫ）。 相似文献
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Kriging without negative weights 总被引：1，自引：0，他引：1
Under a constant drift, the linear kriging estimator is considered as a weighted average ofn available sample values. Kriging weights are determined such that the estimator is unbiased and optimal. To meet these requirements, negative kriging weights are sometimes found. Use of negative weights can produce negative block grades, which makes no practical sense. In some applications, all kriging weights may be required to be nonnegative. In this paper, a derivation of a set of nonlinear equations with the nonnegative constraint is presented. A numerical algorithm also is developed for the solution of the new set of kriging equations. 相似文献
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A note on programs performing kriging with nonnegative weights 总被引：3，自引：0，他引：3
Christina Herzfeld 《Mathematical Geology》1989,21(3):391-393
This note deals with the problem of solving kriging systems with nonnegative weights. Mathematically the question is considered as a case of quadratic programming. Hints concerning computational approaches and software are given. 相似文献
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地质统计学K-阶套合球状模型参数的自动模拟 总被引：1，自引：0，他引：1
本文以地质统计学参数估计的线性规划法为基础,推导出ｋ－阶套合球状模型参数的计算机自动化模拟算法,用ＭｉｃｒｏｓｏｆｔＶｉｓｕａｌＢａｓｉｃ开发出了相应的参数模拟计算机程序。使ｋ－阶套合球状模型的参数模拟实现了自动化 相似文献
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End-member modeling of compositional data: Numerical-statistical algorithms for solving the explicit mixing problem 总被引：18，自引：0，他引：18
Gert Jan Weltje 《Mathematical Geology》1997,29(4):503-549
Linear mixing models of compositional data have been developed in various branches of the earth sciences (e.g., geochemistry,
petrology, mineralogy, sedimentology) for the purpose of summarizing variation among a series of observations in terms of
proportional contributions of (theoretical) end members. Methods of parameter estimation range from relatively straightforward
normative partitioning by (nonnegative) least squares, to more sophisticated bilinear inversion techniques. Solving the bilinear
mixing problem involves the estimation of both mixing proportions and end-member compositions from the data. Normative partitioning,
also known as linear unmixing, thus can be regarded as a special situation of bilinear unmixing with (supposedly) known end
members. Previous attempts to model linear mixing processes are reviewed briefly, and a new iterative strategy for solving
the bilinear problem is developed. This end-member modeling algorithm is more robust and has better convergence properties
than previously proposed numerical schemes. The bilinear unmixing solution is intrinsically nonunique, unless additional constraints
on the model parameters are introduced. In situations where no a priori knowledge is available, the concept of an “ optimal
” solution may be used. This concept is based on the trade-off between mathematical and geological feasibility, two seemingly
contradictory but equally desirable requirements of the unmixing solution. 相似文献
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Hamid Mahmoudabadi Mohammad Izadi Mohammad Bagher Menhaj 《Computational Geosciences》2009,13(1):91-101
In the present paper, a new hybrid method is proposed for grade estimation. In this method, the multilayer perceptron (MLP)
network is trained using the combination of the Levenberg–Marquardt (LM) method and genetic algorithm (GA). Having a few samples
for grade estimation, it is difficult to get a proper result using some function approximation methods like neural networks
or geostatistical methods. The neural network training methods are very sensitive to initial weight values when there are
a few samples as a training dataset. The main objective of the proposed method is to resolve this problem. Here, our method
finds the optimal initial weights by combining GA and LM method. Having the optimal initial values for weights, the local
minima are avoided in the training phase and subsequently the neural network sustainability is trained optimally. Furthermore,
the hybrid method is applied for grade estimation of Gol-e-Gohar iron ore in south Iran. The proposed method shows significant
improvements compared to both conventional MLP and Kriging method. The efficiency of the proposed method gets more highlighted
when the training data set is small. 相似文献