从受训神经-模糊模型中提取知识     

冯天瑾  于树松  程军娜 《中国海洋大学学报(自然科学版)》2003,33(1):107-114

本文对用于模式分类、函数逼近、参数估计的多层感知器 (MLPs)给出 1个清晰的关于内部行为的解释。作者以单隐层的 MLP为例 ,论述了关于 MLP的内部行为的半线性分析理论。对受训的MLP,将隐层单元的输出分别定义为网络输出的正、负“内部分量”;定义内部分量的连接权重集为给定问题的“内部判别模式”;建立了 MLP和模糊集相结合的新模型 ;分析了 MLP的结构为 N- 2 - 1和N- H- 1 ,给出权重初始化的方法 ;提出了 1种从受训神经 -模糊模型 (NFMs)中提取知识的全新的具有实用价值的方法。  相似文献   

运用德尔菲调查—灰色统计法确立水库鱼产力综合评价中的指标权重体系   总被引：1，自引：0，他引：1  

焦念志 《海洋湖沼通报》1992,(4)

本文运用德尔菲方法对水库鱼产力综合评价中指标权重的合理分配问题作了专家调查,并采用灰色统计法对调查结果进行归纳处理,从而确立了一个水库鱼产力影响因素诸层次各方面的评价指标权重体系,可供今后的评价工作参考使用。  相似文献   

Use of Geomorphological Information in Indirect Landslide Susceptibility Assessment   总被引：31，自引：6，他引：31  

van Westen  C. J.  Rengers  N.  Soeters  R. 《Natural Hazards》2003,30(3):399-419

The objective of this paper is to evaluate the importance of geomorphological expert knowledge in the generation of landslide susceptibility maps, using GIS supported indirect bivariate statistical analysis. For a test area in the Alpago region in Italy a dataset was generated at scale 1:5,000. Detailed geomorphological maps were generated, with legends at different levels of complexity. Other factor maps, that were considered relevant for the assessment of landslide susceptibility, were also collected, such as lithology, structural geology, surficial materials, slope classes, land use, distance from streams, roads and houses. The weights of evidence method was used to generate statistically derived weights for all classes of the factor maps. On the basis of these weights, the most relevant maps were selected for the combination into landslide susceptibility maps. Six different combinations of factor maps were evaluated, with varying geomorphological input. Success rates were used to classify the weight maps into three qualitative landslide susceptibility classes. The resulting six maps were compared with a direct susceptibility map, which was made by direct assignment of susceptibility classes in the field. The analysis indicated that the use of detailed geomorphological information in the bivariate statistical analysis raised the overall accuracy of the final susceptibility map considerably. However, even with the use of a detailed geomorphological factor map, the difference with the separately prepared direct susceptibility map is still significant, due to the generalisations that are inherent to the bivariate statistical analysis technique.  相似文献   

Application of Weights of Evidence to Mineral Potential Mapping of Yujiacun Ore Field in Northwest Yunnan Province, China   总被引：1，自引：0，他引：1  

ZHAO　Pengda 《中国地质大学学报(英文版)》2003,14(3):269-273

The multivariate information conprehensive processing technique is especially important at present to the digital mineral prospecting. However, the GIS-based weights of evidence have provided us with powerful tool for the quantitative assessment of mineral resource potential. In this paper, the mineralization model is established, based on the achievements made by previous researchers, to mend such deficiencies ad few references on ore fields in Yujiacun, Yunnan Province and the shortage of quantitative prediction and assessment of mineral resources. In addition, the weights of evidence are used to make a systematic quantitative prediction and assessment of mineral resources there, so that 2 mineral prospecting target areas of grade Ⅰ and 8 mineral prospecting target areas of grade Ⅱ are delineated, providing the further mineral resource exploration with the basis for the selection of mineral deposits.  相似文献   

Anisotropic migration weight for amplitude-preserving migration and sensitivity analysis     

D. Kiyashchenko  B. Kashtan  R.-E. Plessix 《Geophysical Journal International》2004,157(2):753-763

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BAYES方差分量估计在虚拟权平差中的应用     

覃辉 《四川测绘》1994,17(3):110-114

本文把近似Bayes方基分量估计公式应用于矿区扩建网的虚拟权平差中，解决了具体计算中的一些实际问题，最后，通过一矿区扩建网平差实例验证了该方法的可行性．  相似文献   

Spatial Analysis Techniques as Successful Mineral-Potential Mapping Tools for Orogenic Gold Deposits in the Northern Fennoscandian Shield,Finland   总被引：1，自引：0，他引：1  

Vesa Nykänen  V. Juhani Ojala 《Natural Resources Research》2007,16(2):85-92

Geoscientific Information Systems (GIS) provide tools to quantitatively analyze and integrate spatially referenced information from geological, geophysical, and geochemical surveys for decision-making processes. Excellent coverage of well-documented, precise and good quality data enables testing of variable exploration models in an efficient and cost effective way with GIS tools. Digital geoscientific data from the Geological Survey of Finland (GTK) are being used widely as spatial evidence in exploration targeting, that is ranking areas based on their exploration importance. In the last few years, spatial analysis techniques including weights-of-evidence, logistic regression, and fuzzy logic, have been increasingly used in GTK’s mineral exploration and geological mapping projects. Special emphasis has been put into the exploration for gold because of the excellent data coverage within the prospective volcanic belts and because of the increased activity in gold exploration in Finland during recent years. In this paper, we describe some successful case histories of using the weights-of-evidence method for the Au-potential mapping. These projects have shown that, by using spatial modeling techniques, exploration targets can be generated by quantitatively analyzing extensive amounts of data from various sources and to rank these target areas based on their exploration potential.  相似文献   

相关稳健估计及其在测量数据     

姚宜斌  刘经南  施闯 《测绘信息与工程》2001,(3):5-8

在对现有的基于等价权的稳健估计的弊端进行分析的基础上,直接从方差膨胀模型出发,建立起一套基于调整观测量方差-协方差阵的相关稳健估计方法,并通过算例证明其估计思想、模型的正确性和可行性.  相似文献   

Application of GIS Processing Techniques for Producing Mineral Prospectivity Maps—A Case Study: Mesothermal Au in the Swayze Greenstone Belt,Ontario, Canada   总被引：1，自引：0，他引：1  

Harris  J. R.  Wilkinson  L.  Heather  K.  Fumerton  S.  Bernier  M. A.  Ayer  J.  Dahn  R. 《Natural Resources Research》2001,10(2):91-124

A Geographic Information System (GIS) is used to prepare and process digital geoscience data in a variety of ways for producing gold prospectivity maps of the Swayze greenstone belt, Ontario, Canada. Data used to produce these maps include geologic, geochemical, geophysical, and remotely sensed (Landsat). A number of modeling methods are used and are grouped into data-driven (weights of evidence, logistic regression) and knowledge-driven (index and Boolean overlay) methods. The weights of evidence (WofE) technique compares the spatial association of known gold prospects with various indicators (evidence maps) of gold mineralization, to derive a set of weights used to produce the final gold prospectivity map. Logistic regression derives statistical information from evidence maps over each known gold prospect and the coefficients derived from regression analysis are used to weight each evidence map. The gold prospectivity map produced from the index overlay process uses a weighting scheme that is derived from input by the geologist, whereas the Boolean method uses equally weighted binary evidence maps.The resultant gold prospectivity maps are somewhat different in this study as the data comprising the evidence maps were processed purposely differently for each modeling method. Several areas of high gold potential, some of which are coincident with known gold prospects, are evident on the gold prospectivity maps produced using all modeling methods. The majority of these occur in mafic rocks within high strain zones, which is typical of many Archean greenstone belts.  相似文献   

一种气候预测综合决策的方法——递归正权综合决策法   总被引：2，自引：0，他引：2  

项静恬  陈国珍  刘海波  赵振国 《大气科学》1999,23(5):551-558

根据气候预测的特点，提供了以误差平方和为风险函数，以正权综合为模式的多途径气候预测决策方案。不仅从理论上论证了几种正权方法的优性，还提供了递归技巧，进一步提高了正权综合的预测精度。对1997年汛期降水预测所做的综合决策表明，该方法具有较好的综合决策能力。  相似文献