Extended weights of evidence modeling for the pseudo-estimation of metal grades   总被引：4，自引：0，他引：4  

Guocheng Pan 《Natural Resources Research》1996,5(1):53-76

The weights of evidence modeling (WEM) for binary patterns is extended to take account of general categorical variables. The extension makes it possible to use the weights of evidence model in estimating the conditional probability distributions of metal grades. First, the target feature is converted into a set of binary target indicators. Second, the posterior probabilities are estimated for each of the target categories. Third, the estimates are combined to yield the posterior probability distribution of the target feature. Finally, the pseudometal estimates are derived from the probability distribution. The metal grade estimates are prefixed with pseudo, because the estimates are created from indirect evidence (explanatory variables). The pseudo-estimates provide a unique quantitative means to the delineation of exploration targets. This advantage reduces the ambiguities of target selection based solely on probability estimates. In order to use the generalized WEM, continuous geoscience attributes must be converted into categorical variables by means of optimal segmentation based on the target attribute of interest. The segmentation may be viewed as a process of defining evidence of the target feature. The extended weights of evidence model is demonstrated on a case study to select gold targets of Carlin type. The dataset used in the modeling includes apparent resistivity fields, soil geochemical samples, lithological and alteration information, and structural data.  相似文献   

A siliceous chrysophycean cyst-based pH transfer function for Central European lakes   总被引：2，自引：0，他引：2  

Eva Facher  Roland Schmidt 《Journal of Paleolimnology》1996,16(3):275-321

The surface sediments of 50 Central European low to high mountain, acid-sensitive lakes were examined for chrysophycean stomatocysts. One hundred and twenty sic siliceous stomatocyst morphotypes were differentiated by using scanning electron microscope (SEM), counted and illustrated (light microscopy and SEM). Canonical Correspondence Analysis (CCA) showed that pH is the most important measured variable in explaining the cyst distributions, with a strong correlation to the first axis (r²=-0.78). Simple Weighted Averaging (WA) regression and calibration was performed to generate a transfer function for lake water pH. Finally, the transfer function was evaluated by reconstructing pH for a short annually laminated and ¹³⁷Cs dated core from Lake Plené, a strongly acid lake, in the Bohemian Forest. A comparison of the measured and inferred pH values indicates that the model has good predictive power. The cyst-inferred pH and the diatom-inferred pH both indicate that pH was low during the 1970s and that the lake has experienced recovery in recent years.  相似文献   

一个植被模式的检验和它在陆气相互作用中的应用   总被引：8，自引：1，他引：7  

薛永康  曾凡荣  Adam C. Schlosser  Samon J. Allen 《大气科学》1998,22(4):575-599

简要介绍了一个植被模式（Simplified Simple Biosphere Model）的发展过程及其在气候研究中的作用。许多观测资料被用来检验和标定这个模式。文中着重介绍了俄罗斯土壤湿度资料和非洲的HAPEX-Sahel观测资料如何帮助我们改进模式和对陆面过程的机制的认识,对观测误差的影响也作了讨论。在地气相互作用中,着重讨论了东亚地气作用的特征。在文中介绍的两个东亚地区的试验中,尽管地面的异常被假设在东亚的两个不同的地区,但都对夏季风传输途径上的降水有很大影响。最后用一个区域模式对陆面模式在预测试验中的应用作了简介。初步的结果显示,这将是一个有很大发展潜力的新领域。  相似文献   

GPS移动目标实时监控系统的设计与实现   总被引：2，自引：0，他引：2       下载免费PDF全文

龚国清 《地球科学》1998,23(4):412-414

随着计算机科学技术的发展,ＧＩＳ,ＧＰＳ技术越来越多地被人们所重视,并已经被广泛应用到诸多领域．简述了对移动目标监控系统的总体结构设计,着重介绍了软件的开发以及系统的功能,最后扼要地说明了移动目标实时监控系统的应用情况．  相似文献   

秦岭及邻区磷矿成矿问题研讨     

彭大明 《化工矿产地质》1998,20(1):11-16

秦岭及其邻区地处华北地台南缘、秦岭地槽、松潘 甘孜地块、扬子地台北缘 ,可划分皖鄂、鄂西、陕南、什 (邡 )绵 (竹 )等 4个磷矿密集区。成矿时代自元古宙至泥盆纪 ,以震旦纪、寒武纪为高峰期。矿床以沉积型为主 ,次为沉积变质型及岩浆型。特大型、大型矿床成矿受海盆地控制 ,中、小型矿床则受海沟、海槽或海湾制约。区内可归纳出 3级成矿远景区 ,8个成矿域  相似文献   

地区综合实力的灰色聚类评价   总被引：6，自引：0，他引：6  

冯利华 《地域研究与开发》1998,(Z1)

根据灰色聚类分析的原理与方法,对金华市等县（市）社会经济发展进行了灰色聚类分析,确定了该地区各县（市）综合实力的等级,为进一步深化改革、持续发展提供重要的依据  相似文献   

EGMA系统及其应用效果——找矿靶区的定位预测   总被引：1，自引：0，他引：1  

杜佩轩 《物探与化探》1998,22(5):371-378

利用区域地球化学勘查数据,经过窗口滑动平均,计算出滑动窗口的衬值,通过衬值圈定单元素和多元素累加(累乘)异常;在窗口滑动平均值基础上勾绘单元素和多元素背景曲线图、累加(累乘)多元素衬值异常和背景曲线图,制作找矿靶区定位预测图。列述在新疆和秦巴某矿带的应用效果。  相似文献   

The “Three-Component” Digital Prospecting Method: A New Approach for Mineral Resource Quantitative Prediction and Assessment     

Zhao?PengdaEmail author  Chen?Jianping  Chen?Jianguo  Zhang?Shouting  Chen?Yongqing 《Natural Resources Research》2005,14(4):295-303

Stimulated by the exceeding progress of information technology, the development of mineral exploration has entered a new period of digitization and quantification. The “three components” approach of mineral prediction is suggested as a new approach to the “digital mineral prospecting,” which is based on the geoanomaly analysis, directed by the research on the diversity of mineralization and on the spectrum of mineral deposits. Close combination of these three aspects of quantitative study makes a new starting point to the digital prospecting. In this paper, the basic theories of the “three components” approach of mineral prediction are discussed. In addition, based on the new achievements in the studies on the prediction and assessment of solid minerals and gas–oil resources, we have centered our discussion on the thought of analysis of geoanomaly evolution and on the “5P” method for approaching the target area in the “three components” approach of mineral prediction.  相似文献   

Theoretical Model and Random Simulation for Nonlinear Interaction of Irregular Waves with Vertical Wall     

Hong Guangwen Feng Weibing Professor  Hohai University  Nanjing Master of Science  Hohai University  Nanjing 《中国海洋工程》1993,(3)

According to the theoretical solutions for the nonlinear three-dimensional gravity surface waves and their interactions with vertical wall previously proposed by the lead author, in this paper an exact second-order random model of the unified wave motion process for nonlinear irregular waves and their interactions with vertical wall in uniform current is formulated, the corresponding theoretical nonlinear spectrum is derived, and the digital simulation model suitable to the use of the FFT (Fast Fourier Tansform) algorithm is also given. Simulations of wave surface, wave pressure, total wave pressure and its moment are performed. The probability properties and statistical characteristics of these realizations are tested, which include the verifications of normality for linear process and of non-normality for nonlinear process; the consistances of the theoretical spectra with simulated ones; the probability properties of apparent characterstics, such as amplitudes, periods, and extremes (maximum and minimum, positive and negative extremes). The statistical analysis and comparisons demonstrate that the proposed theoretical and computing models are realistic and effective, the estimated spectra are in good agreement with the theoretical ones, and the probability properties of the simulated waves are similar to those of the sea waves. At the same time, the simulating computation can be completed rapidly and easily.  相似文献   

Fish behaviour and orientation-dependent backscatter in acoustic Doppler profiler data     

Zedel  Len; Patro  Ranjan; Knutsen  Tor 《ICES Journal of Marine Science》2005,62(6):1191-1201

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