Elicited Data and Incorporation of Expert Opinion for Statistical Inference in Spatial Studies

Spatial data are often sparse by nature. However, in many instances, information may exist in the form of soft data, such as expert opinion. Scientists in the field often have a good understanding of the phenomenon under study and may be able to provide valuable information on its likely behavior. It is thus useful to have a sensible mechanism that incorporates expert opinion in inference. The Bayesian paradigm suffers from an inherent subjectivity that is unacceptable to many scientists. Aside from this philosophical problem, elicitation of prior distributions is a difficult task. Moreover, an intentionally misleading expert can have substantial influence on Bayesian inference. In our experience, eliciting data is much more natural to the experts than eliciting prior distributions on the parameters of a probability model that is a purely statistical construct. In this paper we elicit data, i.e., guess values for the realization of the process, from the experts. Utilizing a hierarchical modeling framework, we combine elicited data and actual observed data for inferential purposes. A distinguishing feature of this approach is that even an intentionally misleading expert proves to be useful. Theoretical results and simulations illustrate that incorporating expert opinion via elicited data substantially improves the estimation, prediction, and design aspects of statistical inference for spatial data.     

梁河锡矿矿床地质特征及成因探讨

梁河锡矿床是滇西锡矿带西亚带的主要的矿床类型之一。该矿床位于印度板块与欧亚板块碰撞带前缘的腾冲一梁河弧形构造的转折部位,东邻三江构造带。通过对矿床地质背景、矿床地质特征、控矿因素、成矿物质来源及矿床成因等研究,结果表明该矿床与喜山期的花岗岩岩浆活动有着密切的时空关系和成因联系,表明成矿物质来源于喜山期深部花岗岩浆,矿床属于与花岗岩岩浆活动有关的热液矿床。     

大陆造山带区调填图中几个地质问题及其研究方法探讨

对我国区调填图工作历程与现状进行概述基础上,对造山带的主要特点,构造岩片的含义,构造岩片填图法的理论依据、基本工作程序及实施要点作了论述;对造山带中常见的"混杂岩"、强烈构造变形变质的层状变质岩、穹隆状变质地质体的主要特征、产出的地质构造条件及其成因机制等进行了较全面总结和分析;建议将"混杂岩"和"穹隆状变质地质体"分别划分为蛇绿混杂岩、火山混杂岩、滑积混杂岩、构造混杂岩和变质核杂岩、花岗岩底辟穹隆(岩浆核杂岩)、片麻岩穹隆、构造穹隆等类型。     

一种展示盆地地层构造的地质体建模方法

针对地质体建模中的地层-构造恢复与数据更新问题,提出了一种适合重现地下地层-构造格架的方法,并给出了相应的实现算法。该方法采取面向对象的数据体设计思想,结合目前比较流行的面剖分和体元剖分的优点,屏弃了面剖分和体剖分中烦琐而粗糙的逻辑存储方式,从而克服了各自的缺点。通过设计数据库和一系列的点、线、面、区块,将空间数据和属性数据方便而快捷地存储和表示,快速实时地生成地下地质体的各种几何元素,并很好地得到与保存它们之间的空间关系和拓扑结构。,通过借鉴“分而治之”的思想,采取区块分割的思路,将工作区分成一系列井然有序的区块对象。当有新的数据到来的时候,更新数据库,生成一系列新的点、面等对象,进而搜索受到新数据影响的区块对象,只对那些受到影响的区块对象进行处理,这样就避免了对整个工作区全部重新建模,实现数据和模型的快速更新。通过实验数据的验证,该方法很大程度上提高了建模效率,并能实现数据的自更新,节省了大量手工工作。     

A stochastic model of fractional crystallization and its application to the Japanese geosynclinal basalt

A stochastic model of the magmatic differentiation by fractional crystallization is given. The probability distribution of the quantity of crystallized solid removed from silicate melt was assumed to be binomial at any stage of the differentiation. According to this model, when concentrations of an element are transformed into their powers by using the reciprocal of the difference between bulk-partition coefficient for the element and unity as an exponent, the resultant frequency-distribution pattern becomes absolutely normal. The patterns of concentrations, however, cannot be expressed by a particular type of function but are variable according to the values of bulk-partition coefficients. Frequency distributions of element concentrations were computed under selected conditions on the basis of the model. The result shows that the skewed pattern often observed in frequency distributions of minor-element concentrations is explained by this fractional crystallization process. The frequency distributions of Ni and Cr concentrations in the geosynclinal basalt of southwestern Japan were examined in terms of this model. It was concluded that the model can be applied to the formation of the basalt concerning at least these two elements.     

A Statistical Approach to Predict the Effect of Confinement on the Detonation Velocity of Commercial Explosives

Summary Commercial explosives behave non-ideally in rock blasting. A direct and convenient measure of non-ideality is the detonation velocity. In this study, an alternative model fitted to experimental unconfined detonation velocity data is proposed and the effect of confinement on the detonation velocity is modelled. Unconfined data of several explosives showing various levels of non-ideality were successfully modelled. The effect of confinement on detonation velocity was modelled empirically based on field detonation velocity measurements. Confined detonation velocity is a function of the ideal detonation velocity, unconfined detonation velocity at a given blasthole diameter and rock stiffness. For a given explosive and charge diameter, as confinement increases detonation velocity increases. The confinement model is implemented in a simple engineering based non-ideal detonation model. A number of simulations are carried out and analysed to predict the explosive performance parameters for the adopted blasting conditions.     

A statistical model for foraminiferal paleobathymetry, with application to the middle Miocene of the Hokuroku district, Japan

A paleobathymetric Bayes estimator, based on a uniform prior distribution of foraminiferal species over the depth range from 0 to 5000 m, is developed and calibrated from the occurrence of 35 species of foraminifera from present day sites on the Pacific and Indian Ocean seafloors. The species are grouped into 12 clusters in order to more nearly satisfy the independence assumptions of the model. Objective depth-independent criteria are developed for ruling certain samples inadmissible for estimation. The accuracy of the estimator is assessed by comparing estimated and measured depths for the admissible calibration samples, yielding a mean absolute error of estimation of between 300 and 400 m. The depth estimator is applied to foraminifera-bearing Miocene samples from the Hokuroku district of Japan, where paleobathymetric depths of between 3000 and 4000 m are indicated at the time of massive sulfide ore formation.     

地下水水平井流的模型及数值模拟方法—考虑井管内不同流态

评述用线汇刻画水平井管可能存在的问题, 并用理想模型证明.提出考虑井管不同流态(线性流与非线性流) 水流阻力的水平井流的模型, 并将内边界取在水平井的出水口处, 避免了采用线汇刻画水平井管时假定其流量分布和水头分布的困难.运用作者提出的等效渗透系数的概念与确定方法, 将水平井-含水层系统视为含有圆柱形透镜体的非均质含水层, 给出新的水平井流的数学模型.求解了一个理想模型, 得出河下水平井开采地下水的动态.      

基于GIS的信息量法及其地质灾害易发性评价应用——以滇中晋宁县为例

地质灾害易发性评价是地质灾害评价工作的基础,是地质灾害研究的重点。以往地质灾害易发性分区评价大部分依据专家的主观经验,从而导致评价结果具有较大的随意性。本文利用研究区实际调查资料,选取地形地貌、工程地质岩组、地质构造、水文地质条件、人类工程活动等参评因子,利用信息量模型在基于GIS的平台对空间数据进行自动叠加分析,得出各影响因子综合影响下的客观的易发性分区结果,然后结合专家的主观经验,经定性与定量综合分析,对分区结果进行进一步的修正,可实现对地质灾害易发性的科学评价。选取晋宁县作为示例区的应用结果与国土资源大调查中的评价结果基本一致,证实该方法切实可行,并具有广泛的推广应用价值。     

A digital model to evaluate the water balance in a typical hardrock environment

A digital model was designed and developed to study the water balance situation in a typical hardrock environment near Hyderabad, Andhra Pradesh. The model was calibrated over a period of six years with observed field hydrographs. An optimum error factor of 0.001 m was chosen and the computer took 47 iterations for outputting the results with the desired accuracy. Prognostic studies were carried out with progressively increasing draft conditions and water levels were observed to be declining even when the draft was less than the recharge. The analysis of the experiments further amended the belief of the earlier workers.     

断陷盆地沉积体系研究新思路:从古地貌、岩性变化、水体深度到沉积体系

单因素分析法与沉积体制研究方法具有不同的研究思路。前者的理论基础是沉积动力学,主要强调与搬运和沉积过程有关的作用,采取由点到面,从局部到整体,从量变到质变的研究思路。这在复杂的断陷盆地中不利于确定沉积体系的整体分布格局。后者则是基于地貌学、现代沉积考察和基准面升降,采取从面到点,由整体到局部,逐渐深入的研究思路,易于控制断陷盆地中沉积体系的整体分布规律。沉积体制研究方法的基本要求是具有丰富、反射品质较好的地震资料。其关键技术包括古地貌恢复、地震反射结构和波形特征识别。通过古地貌恢复,结合现代沉积观察、水体深浅和岩性变化特征,可以确定沉积相客观分布规律。通过研究某一点的地震反射结构和波形分布特征,结合沉积结构、构造、韵律变化,可以确定该点的沉积微相类型。利用沉积体制方法研究了沾化凹陷孤南洼陷沙三段中亚段中部沉积体系平面分布规律。自南而北前积的辫状河三角洲在该区发育前缘亚相,分布于孤南洼陷南部斜坡区域。盆底扇主要分布于洼陷北部,位于孤南断裂坡脚部位。此外,浅湖近岸滩坝滑塌也可形成盆底扇复合体。该时期湖泊较浅,主要发育浅湖亚相,近岸滩坝及席状砂较丰富。