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This paper proposes a new approach of weights of evidence method based on fuzzy sets and fuzzy probabilities for mineral potential mapping. It can be considered as a generalization of the ordinary weights of evidence method, which is based on binary or ternary patterns of evidence and has been used in conjunction with geographic information systems for mineral potential mapping during the past few years. In the newly proposed method, instead of separating evidence into binary or ternary form, fuzzy sets containing more subjective genetic elements are created; fuzzy probabilities are defined to construct a model for calculating the posterior probability of a unit area containing mineral deposits on the basis of the fuzzy evidence for the unit area. The method can be treated as a hybrid method, which allows objective or subjective definition of a fuzzy membership function of evidence augmented by objective definition of fuzzy or conditional probabilities. Posterior probabilities calculated by this method would depend on existing data in a totally data-driven approach method, but depend partly on expert's knowledge when the hybrid method is used. A case study for demonstration purposes consists of application of the method to gold deposits in Meguma Terrane, Nova Scotia, Canada. 相似文献
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Conventional evaluation of quantitative mineral potential has focused on target selection at small scales. Mapping at small scales usually results in large-area targets, which may be suitable for grass-roots exploration or regional evaluation of potential. Unfortunately, the estimates in small-scale exploration are commonly associated with large uncertainties. Large-scale estimation is used for optimal in-fill drilling design and step-out drilling target selection. In-fill drilling helps to confirm ore-grade continuities and translate a portion of geological resources into minable reserves, whereas step-out target estimation is useful for finding new orebodies in the vicinity of known ore deposits. Both of these processes are necessary for mine development and production planning. A comprehensive methodology is proposed here, particularly for large-scale mineral exploration. The central information synthesizer is canonical or indicator favorability analysis. A case study is presented to demonstrate the methodology for large-scale target selection. The study involves a gold-mining district where step-out drilling targets are being sought to expand the resource base. Several drilling targets were delineated in the study region. Two of them were tested through surface sampling with positive results. 相似文献
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Cause-Effect Analysis in Assessment of Mineral Resources 总被引：1，自引：0，他引：1
Cause-effect analyses is a deterministic methodology intended for processing qualitative (e.g. texts, conventional maps) and mixed, qualitative and quantitative, data. The main idea, employed in cause-effect analysis, is the plurality and interaction of causes. This idea is described by mathematical logic formulae that can be converted into a single Boolean equation. The latter represents a mathematical model of a general shape of cause-effect relations for the study problem. In particular, such a model can express relations between some property of the mineralization and features of other geological phenomena. By processing data, logical dependencies satisfying to the theoretical model are determined in a data file. These dependences, expressed by Boolean function formulae, describe cause-effect relations for a case study, and they are used for predicting. Software realizing the cause-effect analysis is an expert system with artificial intelligence capabilities. There are two methods of using the cause-effect analysis in assessment of mineral resources. The first method consists in detecting the regularity in locations of known mineral deposits and occurrences with the following using the regularity formula for generation of predictive maps. The second method is the evaluation of individual mineral occurrences by obtained Boolean formulae expressing cause-effect relations between deposit sizes and geological environment of deposits. Both methods are illustrated by case studies of predicting gold-bearing deposits of Middle Asia in the former USSR. 相似文献
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河相关系研究的各种方法及其间关系 总被引：4，自引：1，他引：4
河相关系的研究旨在寻求河床地貌形态与流域因子的定量关系。除了传统的水文统计方法外,已有多种理论被用来对这一问题进行探索,这些研究方法相互之间都存在一定的关系,发现和认识这些关系将对河相关系的研究产生深刻的影响。本文在这方面作了探讨。 相似文献
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Mineral potential prediction is a process of establishing a statistical model that describes the relationship between evidence variables and mineral occurrences. In this study, evidence variables were constructed from geological, remote sensing, and geochemical data collected from the Lalingzaohuo district, Qinghai Province, China. Based on these evidence variables, a conjugate gradient logistic regression (CG-LR) model was established to predict exploration targets in the study area. The receiver operating characteristic (ROC) and prediction–area (P-A) curves were used to evaluate the effectiveness of the CG-LR model in mineral potential mapping. The difference between the vertical and horizontal coordinates of each point on the ROC curve was used to determine the optimal threshold for classifying the exploration targets. The optimal threshold corresponds to the point on the ROC curve where the difference between the vertical coordinate and the horizontal coordinate is the largest. In exploration target prediction in the study area, the CG algorithm was used to optimize iteratively the LR coefficients, and the prediction effectiveness was tested for different epochs. With increasing iterations, the prediction performance of the model becomes increasingly better. After 60 iterations, the LR model becomes stable and has the best performance in exploration target prediction. At this point, the exploration targets predicted by the CG-LR model occupy 14.39% of the study area and contain 93% of the known mineral deposits. The exploration targets predicted by the model are consistent with the metallogenic geological characteristics of the study area. Therefore, the CG-LR model can effectively integrate geological, remote sensing, and geochemical data for the study area to predict targets for mineral exploration.
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土壤厚度信息对土壤碳储量估算、水文-生态过程模拟等有着重要影响,但我国北方石质山区缺乏现势性好、分辨率高的土壤厚度分布数据及其快速获取方法。基于北方石质山区土壤厚度的分布特点,先将地貌信息和植被类型叠加生成制图单元,再根据每类单元的特征,针对性地选取地形参数和地表覆被参数作为指示土壤厚度空间分布的环境变量,结合少量土壤样点,依据模糊推理模型,构建了基于分层制图策略的土壤厚度空间推测方法。以河北省滦平县虎什哈流域为例,利用从ASTER GDEMs提取的地形变量和从我国环境减灾卫星影像(HJ-A)提取的地表覆被信息对土壤厚度进行了推测。结果表明,该方法精度较高,是利用免费地形和遥感数据进行低成本快速土壤制图的实用途径。 相似文献
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矿物定量分析实验用捷克 FEI 公司生产的 MLA650F 型矿物解离分析仪,采用 MLA 原样法 和 MLA 重矿法分别对毛乌素沙地西南和东南地区典型沙样的矿物组成以及含量进行分析,结果表 明：MLA650F 仪器测量结果的重复性好,精确度高,测得的矿物种类比光学显微镜更丰富,但不能 如同光学显微镜一样直接提供矿物最原始的颜色、形状、透明度、光泽、表面断口等特征。虽然扫 描电镜与光学显微镜测得的单个矿物含量和矿物分析指标存在一定差异,但矿物含量变化趋势基 本一致,均得到毛乌素沙地主要轻矿物以石英-长石为主,重矿物以角闪石-石榴子石为主的结 论。此外,扫描电镜与光学显微镜对同一样品的矿物分析指标变化趋势基本一致,其中 MLA 原样 法与光学显微镜的 Q/TF 和 ATi 指标同化学风化指标 CIA 结果一致,均表明毛乌素沙地西南地区风 化作用较东南地区强。虽然扫描电镜与光学显微镜均能反应沉积物的沉积环境,但在实际工作 中,要注意所使用的数据应建立在同一测量系统内,不同实验室或实验方法测得的实验数据在引 用时要慎重。 相似文献
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A new experiment method is introduced to study the relations between frost heaving strain and stress of soil or fracture rock under different moisture contents, temperatures and stress states. Based on experiments, a new triaxial frost heaving stress-strain relation is presented aiming at tunnel in cold regions. The experimental equipments are strain-controlled and low temperature buildup, and different restrained conditions are controlled by changing the stiffness of a test-force-ring. Then the frost heaving strain and stress of soil or fracture rock can be obtained under different restrained conditions, and the frost heaving stress-strain relation can be got by regression analysis of some feature points. Experiments of saturated sandy soil conducted by this method show that the triaxial frost heaving stress-strain relation could be expressed by logarithmic curves, and the frost heaving stress changes linearly with the logarithm of the frost heaving strain. The stronger the constraint, the smaller the frost heaving strain and the larger the frost heaving stresses. The frost heaving stresses would tend to a limit value with increasing the constraint intensity. The larger the confining pressure, the larger the frost heaving strain and stress. 相似文献
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Zhiguo Long 《International journal of geographical information science》2013,27(10):2006-2025
In this article we show that the Voronoi-based nine-intersection (V9I) model proposed by Chen et al. (2001, A Voronoi-based 9-intersection model for spatial relations. International Journal of Geographical Information Science, 15 (3), 201–220) is more expressive than what has been believed before. Given any two spatial entities A and B, the V9I relation between A and B is represented as a 3 × 3 Boolean matrix. For each pair of types of spatial entities that is, points, lines, and regions, we first show that most Boolean matrices do not represent a V9I relation by using topological constraints and the definition of Voronoi regions. Then, we provide illustrations for all the remaining matrices. This guarantees that our method is sound and complete. In particular, we show that there are 18 V9I relations between two areas with connected interior, while there are only nine four-intersection relations. Our investigations also show that, unlike many other spatial relation models, V9I relations are context or shape sensitive. That is, the existence of other entities or the shape of the entities may affect the validity of certain relations. 相似文献
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Use of GIS layers, in which the cell values represent fuzzy membership variables, is an effective method of combining subjective geological knowledge with empirical data in a neural network approach to mineral-prospectivity mapping. In this study, multilayer perceptron (MLP), neural networks are used to combine up to 17 regional exploration variables to predict the potential for orogenic gold deposits in the form of prospectivity maps in the Archean Kalgoorlie Terrane of Western Australia. Two types of fuzzy membership layers are used. In the first type of layer, the statistical relationships between known gold deposits and variables in the GIS thematic layer are used to determine fuzzy membership values. For example, GIS layers depicting solid geology and rock-type combinations of categorical data at the nearest lithological boundary for each cell are converted to fuzzy membership layers representing favorable lithologies and favorable lithological boundaries, respectively. This type of fuzzy-membership input is a useful alternative to the 1-of-N coding used for categorical inputs, particularly if there are a large number of classes. Rheological contrast at lithological boundaries is modeled using a second type of fuzzy membership layer, in which the assignment of fuzzy membership value, although based on geological field data, is subjective. The methods used here could be applied to a large range of subjective data (e.g., favorability of tectonic environment, host stratigraphy, or reactivation along major faults) currently used in regional exploration programs, but which normally would not be included as inputs in an empirical neural network approach. 相似文献
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Faranak Feizi Amirabbas Karbalaei-Ramezanali Hosein Tusi 《Natural Resources Research》2017,26(4):553-570
This paper presents an AHP–Shannon Entropy weighting approach as a new hybrid method for assigning evidential weights in mineral potential mapping. For demonstrating the proposed method, a case study was selected for porphyry-Cu potential mapping in Markazi Province, Iran. Then, geo-datasets were gathered, and evidence layers were generated for integration by TOPSIS method (via combination of AHP–Shannon Entropy weighting). Finally, the output mineral potential map was evaluated by field checking and chemical analysis of samples. Two outcrops with evidence of a porphyry system were encountered in areas with high potential values. In addition, there was good correlation between high potential values and Cu content of samples taken from the field. Hence, the usefulness of the AHP–Shannon Entropy weighting of evidence for MPM was demonstrated. 相似文献
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关联矩阵法与城市宜居指标的结构关系度量——以中国老年人宜居城市评价指标体系为例 总被引：1，自引：0，他引：1
城市宜居环境综合评价本质上是城市内部包括物质空间、社会文化空间等众多要素之间的结构关系研究。城市系统结构可以分为不同的亚系统,亚系统之间的关系可以用数量方法确定。以中国老年人宜居城市评价指标体系为例,介绍和比较了各种宜居环境评价指标体系指标赋权的方法,应用关联矩阵法确定老年人城市宜居环境各亚系统之间,以及亚系统内部各个指标的重要性。旨在说明关联矩阵法在确定城市结构中各亚系统关联度上具有合理、简便的特点,尤其是具有将客观性与主观性评价相结合的优势。 相似文献
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地缘政治问题是人文地理学新兴的研究热点。但是,已有研究多基于地理环境要素分析国家的地缘环境或定性讨论地缘战略,很少从双边联系角度定量刻画国家间的地缘关系;现有研究的理论基础也比较薄弱。本文基于地缘政治准则理论,运用1971至2017年联合国投票数据和S分值等方法,从中国与其他国家间关系的历史阶段、友好程度和集团归属三个方面定量分析了世界其他国家对中国的友好程度及其地理分布,并针对中美贸易战的背景指出了中国当前的“朋友”和“敌人”。本文进一步运用面板回归模型分析了中国与世界其他各国的非政治双边关系及其发展水平对中国地缘政治准则的影响,论证了地理距离、经济、技术等因素对地缘关系的影响。本文的分析结果对于加强政治地理学的量化分析有启发作用,也能够为中国更好地处理国际关系和制定地缘政治战略提供参考。 相似文献
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基于模糊模式识别理论的土地利用合理性分析 总被引：3，自引：0，他引：3
以模糊模式识别理论为基础 ,采用模糊综合评判法 ,对土地利用结构合理性等级的模糊划分进行了初步的研究。在此基础上 ,以陕西榆林地区土地利用为例 ,通过计算土地利用结构合理性模糊等级序列及其隶属度 ,对该区土地利用结构的合理性进行了模糊等级评判。研究结果显示 :在土地利用研究中模糊综合评判是一种科学合理的研究方法。 相似文献
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The results of unsupervised pattern recognition methods are critically dependent on the measure ofsimilarity used for clustering objects. There is little a priori information available on the relative utilityof various similarity measures. We introduce here an alternative similarity measure based on the metrictensor measure (MTM). Two standard clustering strategies are tested with the proposed similaritymeasure: hierarchical clustering and the K-median method. As data we use the ARCH obsidian data,a data set on Hungarian coal, and trace element data on Hungarian paprika. Differences from theMahalanobis distance measure are described for intraclass relations. 相似文献
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Jian-ming Jiang Ying-hong Wang Wei-jia Liu Yang-guang Xie 《Natural Resources Research》2018,27(3):379-404
Mineral resource royalty is the economic manifestation of mineral resource ownership benefits. In the context of globalized mineral resource allocation, it is inevitable to research the royalty evaluation in order to improve the marketized allocation efficiency of mineral resources. Current studies mostly include theoretical discussions on connotations of royalty and discussions on royalty levy criteria from the macroeconomic perspective. Studies of royalty calculation and application from the microeconomic perspective are not very common. Based on defining the connotations of equity value, a theoretical royalty calculation formula is suggested first in this paper and then a royalty evaluation model is constructed from the perspective of mineral resource endowment conditions with the methods of multiple regression-based analysis and dummy variables. The feasibility and scientific justification of the evaluation model were verified through empirical analysis of iron mines in Anhui Province of China. Compared to previous studies, this paper better interprets the linear relationship between mineral resource endowment conditions and royalty through simulation analysis of their corresponding relation, making up for the inadequacy of macroeconomic royalty studies. Empirical results indicate the following. (1) Endowment conditions of mineral resources are the key influencing factors of royalty rate, and five of these factors (average geological grade, average mining depth, average ore body thickness, hydrogeological condition and beneficial and harmful elements) are important indices in royalty evaluation. (2) Royalty increases with the price rise in the market of mineral products, but the royalty rate will infinitely approach a constant (60.1%). Based on endowment conditions of mineral resources, the royalty evaluation model constructed in this paper can accurately and objectively evaluate mineral resource royalty in different endowment conditions and provide a convenient and practical evaluation method for establishing royalty levy criteria. 相似文献
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Large amounts of digital data must be analyzed and integrated to generate mineral potential maps, which can be used for exploration targeting. The quality of the mineral potential maps is dependent on the quality of the data used as inputs, with higher quality inputs producing higher quality outputs. In mineral exploration, particularly in regions with little to no exploration history, datasets are often incomplete at the scale of investigation with data missing due to incomplete mapping or the unavailability of data over certain areas. It is not always clear that datasets are incomplete, and this study examines how mineral potential mapping results may differ in this context. Different methods of mineral potential mapping provide different ways of dealing with analyzing and integrating incomplete data. This study examines the weights of evidence (WofE), evidential belief function and fuzzy logic methods of mineral potential mapping using incomplete data from the Carajás mineral province, Brazil to target for orogenic gold mineralization. Results demonstrate that WofE is the best one able to predict the location of known mineralization within the study area when either complete or unacknowledged incomplete data are used. It is suggested that this is due to the use of Bayes’ rule, which can account for “missing data.” The results indicate the effectiveness of WofE for mineral potential mapping with incomplete data. 相似文献