Robust LS-SVM regression for ore grade estimation in a seafloor hydrothermal sulphide deposit

Due to the geological complexities of ore body formation and limited borehole sampling, this paper proposes a robust weighted least square support vectormachine (LS-SVM) regression model to solve the ore grade estimation for a seafloor hydrothermal sulphide deposit in Solwara 1, which consists of a large proportion of incomplete samples without ore types and grade values. The standard LS-SVM classification model is applied to identify the ore type for each in complete sample. Then, a weighted K-nearest neighbor (WKNN) algorithm is proposed to interpolate the missing values. Prior to modeling, the particle swarm optimization (PSO) algorithm is used to obtain an appropriate splitting for the training and test data sets so as to eliminate the large discrepancies caused by randomdivision. Coupled simulated annealing (CSA) and grid search using 10-fold cross validation techniques are adopted to determine the optimal tuning parameters in the LS-SVM models. The effectiveness of the proposed model by comparing with other well-known techniques such as inverse distance weight (IDW), ordinary kriging (OK), and back propagation (BP) neural network is demonstrated. The experimental results show that the robust weighted LS-SVM outperforms the othermethods, and has strong predictive and generalization ability.     

GIS中的数据转换与代数同构分析

对GIS中常见的数据转换进行了细致的研究 ,为数据转换中的质量保证提供了一种理论上严谨的检验手段 ,首次提出了用代数同构的思想来检测网络环境下数据共享的可信度     

一种红色砭石的矿物学特征研究

采用X射线粉末衍射（XRD）、扫描电子显微镜（SEM）、热重分析（TG-DTG）及激光诱导离解光谱（LIBS）等分析方法对一种红色砭石的矿物学特征进行了深入的研究。XRD分析表明,红色砭石主要由白云石组成,并含有少量石英和方解石及微量云母、正长石和赤铁矿。SEM结果显示,砭石中的矿物颗粒大多为集合体,粒径大多集中在1～5μm之间,表面光滑程度有所不同。红色砭石在650-850℃范围内出现一个单失重峰,为白云石的分解形成,类质同象或者杂质矿物的存在导致白云石两阶段的分解同步完成。红色砭石的颜色可能与赤铁矿和正长石微晶在砭石中的均匀分布有关。     

红透山黄铁矿的红外光谱研究

为了深入研究黄铁矿物理性质的实际成因意义,利用NICOLET 380型,分辨率＞0.9 cm-1傅立叶变换红外光谱仪,对红透山地区不同中段的黄铁矿样品进行测量,在400~4 000 cm-1范围内分别得出红外光透射光谱图。运用朗伯比尔定律计算出各中段样品的吸光度。结果表明：红透山黄铁矿(FeS2)中存在不同程度的类质同象取代,该区域黄铁矿导电类型为n型。认为此种类质同象与黄铁矿形成部位具有相关性。吸光度比值与样品所在深度负相关。     

电子探针分析与系列矿物研究

本文论述以电子探针为主要测试手段对下述几种系列矿物的研究成果:(1)铂族元素系列矿物的研究(包括Ru-Os-Fe金属互化物矿物系列和RuAs_2-OsAs_2二元固溶体矿物系);(2)Au-Cu系列矿物的研究;(3)黝铜矿族矿物的研究。     

纳米比亚欢乐谷地区白岗岩型铀矿矿物特征研究

本文通过系统的岩矿鉴定和电子探针分析,对纳米比亚欢乐谷地区白岗岩型铀矿的矿物特征进行了详细的研究.该地区铀的赋存形式以独立铀矿物为主,少量以类质同像形式存在于钍矿物中.铀矿物的主要种类有:晶质铀矿、钍铀矿、铀石、铀钍石、钛铀矿、沥青铀矿、硅钙铀矿和钒钾铀矿等,其中,晶质铀矿、钍铀矿和钛铀矿等原生铀矿物约占69％,而反应边状铀石、铀钍石、沥青铀矿、钒钾铀矿和硅钙铀矿等次生铀矿物约占31％.由此可见,该区铀矿化主要表现为原始岩浆的分异作用与后期热液改造作用的相互叠加,其热液改造程度不大,仅使铀发生内部再分配.     

线性模型下的不完全样本

设有线性模型Y=xβ+ε,这里Y是一个m维随机向量,x是一个已知m×p阵,ε是一个m维随机误差向量,E_ε=0,V_(αγε)=σ~2Im,β和σ~2>0都是未知的。设我们得到子样Y_1,Y_2,…,Y_n,由于某些原因,Y_i(i=1,2,…,n)的某些分量得不到,我们称此为不完全样本。本文得到了所有β的可估线性函数、所有叶估线性函数的LSE以及基于残差的σ~2的无偏估计在完全样本与不完全样本下相同的充要条件。     

Seismic hazard in East Africa: An example of the application of incomplete and uncertain data

Earthquake hazard parameters maximum regional magnitude M _max and annual activity rate , and the b parameter of the Gutenberg-Richter relation have been evaluated for parts of East Africa. The applied maximum likelihood method permits the combination of both historical and instrumental data available (the catalog used here covers the interval 1880–1979). In addition, the uncertainty involved in magnitude determination and thresholds of completeness were taken into account. The hazard-parameter determination was performed for two study areas corresponding to segments of the eastern and western branches of the East African rift system. The results for these areas show differences that can be partly explained through the characteristics of the data.     

Strategies for Reducing Computing Time of Nuclear Waste Management Simulations Using the PORFLOW ™ Software

PORFLOW is a CFD software which is dedicated to groundwater flow and nuclear waste management simulations. PORFLOW is developed by the ACRi company located in Bel Air (California, USA) (http://www.acricfd.com) with a subsidiary in Sophia Antipolis (France) (http://www.acri.fr). In this paper, we report on our recent efforts to improve the performances of PORFLOW by focusing our attention on the solution of the large sparse linear systems resulting from the space and time discretizations of flow and transport equations. This work is illustrated by applying PORFLOW to the calculation of the COUPLEX1 and part of the COUPLEX2 problems.     

自然界中ZnS-CdS完全类质同象系列的发现和初步研究

过去认为在自然界中的Cd只能有限替代ZnS中的Zn。但是，近几年笔者在研究贵州牛角塘镉锌矿床时，经电子探针、扫描电镜和透射电镜等多种方法的研究，发现锌硫化物中的Cd主要以类质同象存在，其含量可从0．8％增至37．93％；镉硫化物中的Zn同样主要以类质同象存在，其含量为2．43％～38．64％。锌硫化物与镉硫化物成渐变的过渡关系，并且Zn与Cd成很好的负相关关系，相关系数达0．99以上，形成ZnS-CdS的完全类质同象系列。这一发现无论在矿物学，还是在地球化学和矿床学上都具有重要的理论意义和实用价值。