The fractal geometry of the soil—covered landscape     

W. E. H. Culling  Mark Datko 《地球表面变化过程与地形》1987,12(4):369-385

The soil-covered landscape surface can be idealized from two viewpoints. The intuitive view is of a smooth, absolutely continuous surface with continuous contour lines and measurable in integral dimensions. The alternative view emphasizes the roughness, a surface of little regularity and at the limit of no contours, the appropriate measure being that of fractional Hausdorff dimension. Regularity is a local property and both idealizations need to stop far short of the limit to avoid awkward consequences. The dichotomy of viewpoint can be matched in the theory of Gaussian random fields. These, if they are smooth, are very smooth but if they are irregular they are highly irregular (erratic); there is no middle ground. This Belayev dichotomy is defined and both modes applied to the soil-covered landscape. On the one hand, if the landscape is subject to a general diffusive type degradation or more generally a Davisian downwasting regime then the curvature of the landscape surface is progressively straightened and the distribution of gradient (increments) along a typical traverse will eventually adopt a Gaussian form. Then from the irregular viewpoint the surface is ultimately well represented by a fractional Brownian surface of low Hausdorff dimension (2·0 < dim < 2·3). The Hausdorff dimension is directly related to the entropy of the landscape and as degradation proceeds both quantities decrease in value. On the other hand, if the surface is regarded as smooth and well represented by an absolutely continuous Gaussian field then the mean value of the number of upcrossings of a level or the extent of an excursion set will also be Gaussian. This analysis is restricted to one dimension; the number of times a profile curve crosses or the amount of time it spends above any given level. Predictions from both viewpoints are substantially corroborated in a map analysis of 15 sites on varied terrains in Southern England and the map analysis checked against one based upon digital tape data for one of the sites.  相似文献   

断层形变高频波动丛集性前兆和异常判据研究     

葛彦增  卢良玉 《东北地震研究》1996,12(3):15-27

断层形变短临前兆表现形式是多样的，并作了初步分类，丛集性高频波动是其一种重要现形式，探索了这种前兆信息的提取思路和方法，认为信息丛集度Ｃ是描述这种前兆短临信息，熵值积分平滑值Ｇ是描述中短信息较理想的特征量，震例学表明第二类前兆具有较好的预报效能，对异常判据了初步探索。  相似文献   

小波变换在遥感图像数据融合中的应用   总被引：9，自引：0，他引：9  

倪秀平  肖国超  万志龙 《测绘学院学报》1998,(3)

用小波变换实现了一种新的遥感图像数据融合方法 ,该方法采用梯度算法对不同尺度子带数据进行融合 ,用加权法对基带数据进行融合。给出了 SAR图像与 TM图像的融合结果的定性评价 ,并用熵及平均梯度进行了定量评价  相似文献   

Indian summer monsoon rainfall (ISMR) forecasting using time series data: A fuzzy-entropy-neuro based expert system     

Pritpal Singh 《地学前缘(英文版)》2018,9(4):1243-1257

This study presents a model to forecast the Indian summer monsoon rainfall(ISMR)(June-September)based on monthly and seasonal time scales. The ISMR time series data sets are classified into two parts for modeling purposes, viz.,(1) training data set(1871-1960), and(2) testing data set(1961-2014).Statistical analyzes reflect the dynamic nature of the ISMR, which couldn't be predicted efficiently by statistical and mathematical based models. Therefore, this study suggests the usage of three techniques,viz., fuzzy set, entropy and artificial neural network(ANN). Based on these techniques, a novel ISMR time series forecasting model is designed to deal with the dynamic nature of the ISMR. This model is verified and validated with training and testing data sets. Various statistical analyzes and comparison studies demonstrate the effectiveness of the proposed model.  相似文献   

重庆市梁平县农用地节约集约利用分析与研究     

蒋春艳  刁承泰  周强  李占军 《云南地理环境研究》2008,20(2):71-77

以重庆市梁平县1999年到2005年土地利用状况为依据,结合梁平县的自然、社会、经济条件,建立农用地节约集约利用评价指标体系,采用“熵”值法确定各指标权重,利用指标权重法分别对梁平县近7年来农用地节约集约利用状况和2005年重庆市、重庆市三大经济区及其对应代表区县的农用地节约集约利用情况进行纵向及横向评价,得出梁平县农用地节约集约利用度总体呈现提高趋势但较最高水平仍有差距的结论,并针对评价结果提出相应的建议和措施。  相似文献   

利用熵平均法对地面γ能谱数据局部干扰消除的应用研究   总被引：1，自引：0，他引：1       下载免费PDF全文

刘菁华  王祝文  陈树军 《地球物理学报》2010,53(8):1961-1967

阐述了熵平均法对地面γ能谱测量局部干扰的消除的基本原理和方法,应用此方法对浅覆盖区地质填图的γ能谱测量剖面数据及应用γ能谱测量确定古城墙位置的平面测量数据进行了处理,处理结果表明该方法对于消除地表植被及局部土壤元素富集随机干扰、突出弱异常具有明显的效果,使地质填图中进行岩性划分界线明显,考古中古城墙表现的弱异常突出,边界清晰.通过对熵平均法应用的讨论,可以看到5点熵平均对于局部干扰压制较多而对异常削弱较少的特点;与多点平滑相比,熵平均对于突跳点具有更好的压制作用.熵平均法对于地面γ能谱测量随机影响的消除起到了较好的效果,使地面γ能谱测量得到了较好的应用.  相似文献   

基于概率统计的地震岩相识别不确定性定量评价方法          下载免费PDF全文

袁成  李景叶  陈小宏 《地球物理学报》2015,58(10):3825-3836

地震岩相识别能够提供具有不同储层特征的岩相分布信息,对岩相识别的不确定性开展定量评价分析可降低后期油藏建模与储层评价的风险.考虑了地震岩相识别中测井岩相定义、岩石物理建模、井震尺度匹配及地震反演等环节的不确定性对岩相识别的影响,基于概率统计方法,引入熵函数实现了地震岩相识别不确定性定量评价,并结合岩相概率、重建率等多角度综合定量分析不确定性的构成及传递特征,系统地实现了地震岩相识别不确定性评价流程的整体连通.提出了结合属性交绘特征约束反演参数空间,提高地震岩相识别运算效率.模拟数据分析表明利用熵函数可精确实现岩相识别不确定性地定量表征,利用属性交绘特征约束参数空间既大幅度减少运算量,也可降低地震岩相识别的不确定性.  相似文献   

Stochastic observation error and uncertainty in water quality evaluation     

Dong Wang  Vijay P. Singh  Yuan-sheng Zhu  Ji-chun Wu 《Advances in water resources》2009

When evaluating water quality, the influence of physical weight of the observed index is normally taken into account, but the influence of stochastic observation error (SOE) is not adequately considered. Using Monte Carlo simulation, combined with Shannon entropy, the Principle of Maximum Entropy (POME) and Tsallis entropy, this study investigates the influence of stochastic observation error (SOE) for two cases of the observed index: small observation error and large observation error. Randomness and fuzziness represent two types of uncertainties that are deemed significant and should be considered simultaneously when developing or evaluating water quality models. To that end, three models are employed here: two of the models, named as model I and model II, consider both the fuzziness and randomness, and another model, considers only fuzziness. The results from three representative lakes in China show that for all three models, the influence of stochastic observation error (SOE) on water quality evaluation can be significant irrespective of whether the water quality index has a small observation error or a large observation error. Furthermore, when there is a significant difference in the accuracy of observations, the influence of stochastic observation error (SOE) on water quality evaluation increases. The water quality index whose SOE is minimum determines the results of evaluation.  相似文献   

Research on Earthquake Precursor Attractor and Its Predictability     

Li QiangSeismological Bureau of Jiangsu Province  Nanjing  China 《中国地震研究》1999,(3)

Based on the body strain observation data at Liyang and Xuzhou stations, the Correlation Dimension D2 and the second-order Renyi entropy K2 of the attractor are calculated and studied. In addition, a new method of evaluating the longest predictable time of precursor attractor is advanced under the condition of a certain anomalous criterion rule. The conclusion indicates that the body strain precursor attractor is one of the chaotic attractors and it has some determinate change rules such as the dimension declines before an earthquake and the number of the independent factors on which the variation of the system depends is within the range of 5 - 12. The conclusion also indicates that the longest evaluated predictable time of the body strain attractor is 213 days at the Liyang station and 342 days at the Xuzhou station. It is clear that this research can be of great reference value for recognizing the nonlinear behavior of precursor attractors and for evaluating the predictability of different precursor  相似文献   

SAR影像与TM影像的几种融合处理方法   总被引：13，自引：2，他引：11  

陈彩芬  舒宁 《国土资源遥感》1999,10(4):53-57

利用彩色空间变换、比值变换及相关系数法分别对SAR影像与TM3 、TM4 、TM5 三波段影像进行融合处理。文章介绍了影像融合中的具体技术问题及其处理方法。因侧视雷达图像一般有明显的孤立噪声,所以,在进行影像融合处理之前,先对SAR影像进行预处理,文中用δ滤波法抑制孤立噪声(光斑) .最后,从视觉效果、熵、平均梯度值以及标准差等4 方面评价了影像融合的质量。  相似文献