On estimating the parameters in mixtures of circular normal distributions

The method of maximum likelihood used in analyzing data which are bimodal in the range (0, )is lengthy and not always successful. Two alternative methods are proposed and the results compared with those obtained by using the method of maximum likelihood on orientation data from clasts and shells. It is shown that a procedure based on the Method of Moments gives comparable results and is much more practicable.     

基于PCA/NDVI的森林覆盖遥感信息提取方法研究

摘要： 以大兴安岭为试验区，提出将主成分分析（PCA）得到的第1分量、归一化植被指数（NDVI）和Landsat TM 1~TM 7某一波段进行合成，增强森林覆盖区和背景区信息的反差，并利用最大似然法对影像进行监督分类，分类精度超过92%。通过对不同云雾量和森林覆盖的2个时相影像试验表明，本方法提高了遥感影像森林覆盖信息提取的自动化程度和精度。     

An Initial Guess for the Levenberg–Marquardt Algorithm for Conditioning a Stochastic Channel to Pressure Data

A standard procedure for conditioning a stochastic channel to well-test pressure data requires the minimization of an objective function. The Levenberg–Marquardt algorithm is a natural choice for minimization, but may suffer from slow convergence or converge to a local minimum which gives an unacceptable match of observed pressure data if a poor initial guess is used. In this work, we present a procedure to generate a good initial guess when the Levenberg–Marquardt algorithm is used to condition a stochastic channel to pressure data and well observations of channel facies, channel thickness, and channel top depth. This technique yields improved computational efficiency when the Levenberg–Marquardt method is used as the optimization procedure for generating realizations of the model by the randomized maximum likelihood method.     

多母体p—范极大似然平差

本文提出了多母体ｐ－范极大似然平差方法，建立了该方法的数学模型，并且导出了求解参数估值的基础方程，本文提出的方法溶测量平差，误差母体分布的估计、方差分量估计于一体，是对多元ｐ－范极大似然平差的进一步推广。     

一种特殊的后方交会法

本文对特殊的后方交会法的布点、观测、解算作了一般性的介绍，重点讨论了放样允许误差区域的确定．     

基于决策规则的遥感影像土地利用信息提取

遥感作为近几十年迅速发展起来的一门综合性技术学科,己经在许多领域发挥了重大作用。通过对遥感数据进行专题分类处理以得到土地利用等专题信息是遥感最广泛的应用领域之一。尽管土地利用遥感分类方法不断发展,但分类技术始终跟不上遥感技术本身的发展。本论文的主要目标之一就是以沈阳矿区为研究区,利用多源遥感数据结合地面实地调查,围绕遥感图像,采用常规的最大似然分类法,同时采用选用决策树分类方法,对不同数据源得到的信息进行综合分析,充分利用其中的光谱信息、地学知识以及人的经验知识进行土地利用分类,从而更好地为地方土地有效利用提供决策依据。     

CFG桩复合地基极限承载力计算模型及其验证

CFG桩因具有良好的经济性和适用性,工程中得到了越来越广泛地应用,传统的分析方法主要通过桩土承载力迭加获取,与实际施工监测结果误差比较大。在分析了CFG桩复合地基的竖向承载力特性基础上,依据CFG桩复合地基的等沉面上下部分的不同特征,提出了CFG桩复合地基的“双剪切破坏模型”：等沉面以上部分看作太沙基模型的桩体的向上剪切破坏,等层面以下部分看作迈耶霍夫模型的桩体向下的剪切破坏,推导了极限承载力的有关计算模型,讨论了该模型适用条件,并结合工程实例,验证了所提模型的正确性,对CFG桩复合地基工程有一定的指导意义。     

Regional Probabilistic and Statistical Mineral Potential Mapping of Gold–Silver Deposits Using GIS in the Gangreung Area, Korea

The aim of the present study is to analyze relationships between epithermal Au‐Ag deposits of the hydrothermal type and related geological factors and integrate the relationships using probabilistic and statistical models in a geographic information system (GIS) environment. A variety of spatial geological data were compiled, evaluated and integrated to produce a map of potential Au and Ag deposits in the Gangreung area, Korea. This empirical approach assumes that all deposits shared a common genesis. The method consists of three main steps: (i) identification of spatial relationships; (ii) quantification of such relationships and (iii) integration of multiple quantified relationships. A spatial database containing Au and Ag deposits, topographic, geologic, geophysical and geochemical data was constructed using a GIS. The factors relating to 103 Au and Ag mineral deposits are the geological data such as lithology and fault structure, geochemical data including the abundance of Al, As, Ba, Ca, Cd, Co, conductivity, Cr, Cu, Eh, Fe, HCO3–, K, Li, Mg, Mn, Mo, Na, Ni, Pb, pH, Si, Sr, V, W, Zn, Cl^?, F^?, PO₄^3?, NO₂^?, NO₃^? and SO₄^2?, and geophysical data including Bouguer and magnetic anomalies. Using the constructed spatial database, the relationships between mineral deposit areas and 36 related factors are identified and quantified by probabilistic and statistical modeling; that is, likelihood ratio, weights of evidence and logistic regression. All the factors were combined to produce a map of the regional mineral potential using the overlay method in a GIS environment. The mineral potential map was then verified by comparison with known mineral deposits. The verification results give respective accuracies of 82.52%, 72.45% and 81.60% for the likelihood ratio, weights of evidence and logistic regression models, respectively. The mineral potential map can be used as a source of basic information for mineral resource development.     

泊松分布下线性多重回归问题

对一实验数据组进行线性多重回归,如果数据的涨落服从泊松概率分布,常用方法不能给出准确的解。一般地,是假设各泊松分布的形状近似于高斯分布,给出近似解。因此,也存在着人所共知的拟合曲线下的面积亏损问题。本文从最大或然法出发,不加任何假设,严格推导了求解泊松分布线性多重回归的一种方法。按这一方法,“面积亏损”问题在计算精度范围内也得到彻底解决。