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排序方式: 共有259条查询结果,搜索用时 31 毫秒
51.
岩体可爆性分级物元分析模型及其应用 总被引:4,自引:0,他引:4
首次提出用物元分析进行岩体可爆性分级的新方法。该模型将岩体可爆性类别、分类指标及其特征值作为物元,根据岩体可爆性分级标准建立关联函数,通过计算综合关联度判断岩体可爆性类别,用实例与其他方法进行了对比,得到一致的结果。该方法计算简便、分类合理,实用性强。 相似文献
52.
卫星遥感反演土壤水分研究综述 总被引:11,自引:1,他引:11
土壤水分是影响地表过程的核心变量之一。精准地测量土壤水分及其时空分布,长期以来是定量遥感研究领域的难点问题。简要回顾基于光学、被动微波、主动微波和多传感器联合反演等卫星遥感反演土壤水分的主要反演算法、存在的难点和前沿性研究问题,介绍了应用土壤水分反演算法所形成的3种主要全球土壤水分数据集,包括欧洲气象业务卫星(ERS/MetOp)数据集、高级微波扫描辐射计(AMSR-E)数据集、土壤湿度与海洋盐分卫星(SMOS)数据集,并结合目前存在的问题探讨卫星遥感反演土壤水分研究的发展趋势。 相似文献
53.
王蛟 《吉林大学学报(地球科学版)》2007,37(3):500-505
综合研究钻井、古生物和测井资料,认为孤岛油田新近系馆陶组上段馆1 2砂层组沉积时期发育浅水湖泊而非单一的河流相沉积。浅水湖泊湖盆地形平坦,湖面广阔,水体极浅;湖区受气候影响,湖平面频繁振荡式升降变化;沉积物多表现为氧化、还原环境交替的红灰相间的细粒沉积物;湖泊沉积构造发育,生物富集,水进→水退沉积旋回性明显。通过取心井的观察描述和分析化验,识别出水道砂坝、砂坪、混合坪、泥坪和沼泽5种沉积微相类型,建立了孤岛油田馆1 2砂层组浅水湖泊沉积模式。 相似文献
54.
The knowledge rules of debris flow event: A case study for investigation Chen Yu Lan River, Taiwan 总被引:1,自引:0,他引:1
Debris flow, one of the most active hydrological processes, brings about a great loss of life and properties in the Chen Yu Lan River area, Nan-Tou County, Taiwan. The goal of this study is to manage and monitor the debris flows in a vast area. Thus, the strategy is to collect hydraulical and in-situ data easily and quickly through our spatial information system. Then, a novel Data Mining technique will be developed to find a rule-based knowledge system of debris flow. The entire study can be divided into two parts. In the first part, using spatial information the debris flow image is extracted from the outbreak area. The system provides precise positional information pertaining to the debris flow events. Attributes such as effective watershed area, Normalized Difference Vegetation Index (NDVI), and slope are automatically obtained from the system. In the second part of this study, K-mean theory is used to classify the observed hydraulical and in-situ data into different categories. Then, the ‘Effective Rough Set’ method is successfully used to analyze the factors influencing the debris flow phenomenon and delivers rational knowledge rules. The contribution of this study is presented that NDVI, slope and effective watershed area are the major factors influencing debris flow in the study area. The knowledge rules can provide better understanding on the elevation of high potential debris catchments. 相似文献
55.
Traditional and New Ways to Handle Uncertainty in Geology 总被引:3,自引:0,他引:3
The paper presents an overview of the main types of uncertainty in geology. The best guess and uncertainty oriented approaches are outlined. Traditional methods of uncertainty analysis—deterministic and probabilistic—are discussed with special references to their limitations in geology. New mathematical methods, developed during the last decades are suitable to handle uncertainty in geology in scalar, spatial, and spatial-temporal conditions, such as uncertainty intervals, fuzzy sets, probability bounds, neural networks, hybrid arithmetic and fuzzy geostatistics. Geological applicability of these methods is discussed. Uncertainty of risk analysis for geological purposes also is outlined. 相似文献
56.
Eighteen lakes were added to a published training set of 46 British Columbia (BC) lakes in order to expand the original range of total phosphorus (TP) concentrations. Canonical correspondence analysis (CCA) was used to analyze the relationship between diatom assemblages and environmental variables. Specific conductivity and [TP] each explained significant (P0.05) directions of variance in the distribution of the diatoms. The relationship between diatom assemblages and [TP] was sufficiently strong to warrant the development of a weighted-averaging (WA) regression and calibration model that can be used to infer past trophic status from fossil diatom assemblages.The relationship between observed and inferred [TP] was not improved by the addition of more eutrophic lakes, however the [TP] range and the number of taxa used in the transfer function are now superior to the original model. Diatom species assemblages changed very little in lakes with TP concentrations greater than 85 µg 1–1, so we document the development of a model containing lakes with TP85 µg 1–1. The updated model uses 59 training lakes and covers a range of species optima from 6 to 41.9 µg 1–1 TP, and a total of 150 diatom taxa.The updated inference model provided a more realistic reconstruction of the anthropogenic history of a highly eutrophic BC lake. The model can now be used to infer past nutrient conditions in other BC lakes in order to assess changes in trophic status. 相似文献
57.
基于粗糙集理论,以指标集为基础,建立了底板破坏深度影响因素的知识表达系统,提出了规则提取原则,通过粗糙集决策规则的数据处理,得出获得各因素对底板破坏深度的影响顺序为:采深、煤层倾角、工作面斜长、采厚、底板抗破坏能力、工作面是否有切穿型断层或破碎带。由于底板抗破坏能力、工作面是否有切穿型断层或破碎带这些参数难以确定,采用其余4种影响因素建立BP神经网络的预测模型,并根据建立的模型预测肥城煤田的9101和9507工作面的底板破坏深度。通过与实测结果对比,证明该网络模型的计算结果比规程提供的经验公式计算结果更接近实际。 相似文献
58.
Marcello Antonio Ventura Gorini Guilherme Lucio Abelha Mota 《International journal of geographical information science》2016,30(8):1644-1666
A method is presented to explicitly incorporate spatial and scale vagueness – double vagueness – into geomorphometric analyses. Known limitations of usual practices include using a single fixed set of crisp thresholds for morphometric classification and the imposition of a single arbitrary number of scales of analysis to the entire digital elevation model (DEM). Among the advantages of the proposed method are: fuzzification of morphometric classification rules, scale-dependent adaptive fuzzy set parametrization and an objective definition of maximum scale of analysis on a cell-by-cell basis. The method was applied to several DEMs ranging from the ocean floor to surface landscapes of both Earth and Mars. The result was evaluated with respect to modal morphometric features and to characteristic scales, suggesting a more robust method for deriving both morphometric classifications and terrain attributes. We argue that the method would be preferable to any single-scale crisp approach, at least in the context of preliminary hands-off morphometric analyses of DEMs. 相似文献
59.
Plane-wave reflection from a rough surface overlying a fluid half-space, with a sound speed distribution subject to a small and random perturbation, is considered. A theory based upon a boundary perturbation method in conjunction with a formulation derived from Green's function for the coherent field in the random medium have been applied to a typical oceanic environment to study their effects on the plane-wave reflection. By considering the coherent field itself, the plane-wave reflection may be obtained straightforwardly through a procedure consistent with the formalisms currently employed in rough surface scattering. The results show that both the rough surface and medium inhomogenieties may reduce the plane-wave reflection, however, the characteristics of the curves representing their effects are different, enabling us to identify the dominant scattering mechanism. The results for the coherent reflection due to the individual scattering mechanism are compatible with those found in the existing literature. 相似文献
60.
The fundamental principle for differentiating water masses is a strict consideration of their relative "interior homogeneity" and obvious "exterior differences" with others in characteristics. The conceptions of water type, water mass and water system are dealt with on the basis of the theory of fuzzy sets. A proposal to apply the theory of fuzzy sets to define the water mass and its core, independent area, boundary and mixing area is put forward.As an example, the membership function of the surface water masses in the Yellow Sea and East China Sea in August, 1979, are considered. Their cores, independent areas, boundaries, mixing areas and the approximation degrees between different water masses are calculated respectively. The water masses are ranged according to their fuzzy degrees. 相似文献