Multifractal and entropic properties of landslides in Japan   总被引：4，自引：0，他引：4  

C. Goltz 《International Journal of Earth Sciences》1996,85(1):71-84

Landslide distributions in two major areas of northern Japan, Tohoku and Hokkaido, are analysed for multifractal properties. For the latter data set, also the multifractal spectrum for the spatial landslide size distribution is determined and compared to the probability distribution. It is concluded that the fields possess definite multifractal character. This finding is supported by the known multifractality of the main triggering processes, rain and earthquakes. Further support comes from a configuration entropy analysis which is found to be a useful complimentary tool to multifractal analysis. Models leading to multifractality are briefly reviewed. Careful attention is paid to the algorithms used and to the verification of the numerical results. Some general suggestions concerning numerical methods are made.  相似文献   

新疆及其邻区M≥7强震的预测研究   总被引：2，自引：0，他引：2       下载免费PDF全文

门可佩 《地震工程学报》1994,16(4):29-36

新疆及其邻近地区Ｍ≥７强震活动在时间分布上具有明显的有序性。自１７１６年以来的２１次Ｍ≥７强震存在着时间间隔为１１、２５、３０、４１和６０年的有序值。利用强震活动时间的有序性结构，可对该区７级强震进行预测探索。本文同时还应用熵和经验分布函数，讨论了下次强震发生的地点和概率。  相似文献   

超谱遥感图像快速聚类无损压缩算法   总被引：1，自引：0，他引：1  

王朝晖  周佩玲 《遥感学报》2003,7(5):400-406

K-means聚类要求每个像素要和所有聚类中心求欧氏距离，当聚类数很多时，这是一个相当耗时的工作。改进的K—meam聚类算法根据历史聚类结果进行初始类分割，即节约初始聚类时间，又能使历史聚类过程中形成的类间稳定关系得以保持；类内像素只和相邻的聚类中心计算距离进行聚类，随着算法的迭代进行，大量类的状态基本固定，使得聚类速度不断加快。基于改进K-means聚类的无损压缩算法具有充分利用历史聚类成果和收敛速度快的特点，通过提高类内像素冗余度，最大限度消除谱间冗余和空间冗余。采用多次聚类压缩的结果预测最佳聚类数的方法，可实现最小熵无损压缩。通过和DPCM算法概率模型的熵值比较及实验数据的分析，验证了基于聚类无损压缩效率比不聚类无损压缩效果更优。  相似文献   

系统论思想在地貌学中的应用   总被引：1，自引：0，他引：1  

尹国康 《地理学报》1991,46(1):26-34

系统论的思潮及其基本原则迅速地向地貌学领域渗透和扩展,改变着地貌学家的知识结构和思维方式。愈来愈显示出地貌学的一个新的生长点——系统地貌学,将以其强大的生命力萌发出来。它将从系统论与控制论的角度,研究地球表面形态结构及其物质组成与自然环境、社会经济环境之间的相互作用,揭示地貌系统的结构、功能及其演化规律性;对地域分异形成的不同地貌景观,分别建立过程-反应模式。为优化人地系统、合理利用自然资源、建立区域发展最优模式的决策提供科学依据。  相似文献   

APPLICATION OF MEM SPECTRAL ESTIMATION TO MU RADAR OBSERVATION   总被引：1，自引：0，他引：1       下载免费PDF全文

Li Wei  L&#;Daren  Shoichiro Fukao  Mamoru Yamamoto  Toshitaka Tsu  Susumu Kato 《Acta Meteorologica Sinica》1991,5(3):293-298

Preliminary results of the wind velocity estimation using the Maximum Entropy Method (MEM) to MUradar observation data sets are presented. The comparison of the results from the periodogram method and theMEM shows that the MEM estimation is reliable, and has higher accuracy, resolution and detectability than theestimation from periodogram method. The high accuracy power spectrum obtained by the MEM is veryuseful to studying the atmospheric turbulence structure. However. the MEM needs the longer computingtime for obtaining the high accuracy spectrum. Particularly, the estimation of MEM will bring serious devia-tion at lower signal-to-noise ratio.  相似文献   

地震前兆吸引子及可预报性问题研究   总被引：2，自引：0，他引：2  

李强 《中国地震》1998,14(4):71-77

利用溧阳台和徐州台体应变前兆观测资料,计算并研究了地震前兆吸引子的关联维数Ｄ２和二阶Ｒｅｎｙｉ料Ｋ２,提出了在一定异常判据下估算前兆吸引子可预报时间长度的方法。  相似文献   

High-temperature heat capacity and thermodynamic properties for end-member titanite (CaTiSiO5)     

J. Tangeman  D. Xirouchakis 《Physics and Chemistry of Minerals》2001,28(3):167-176

 The heat capacity of end-member titanite and (CaTiSiO₅) glass has been measured in the range 328–938 K using differential scanning calorimetry. The data show a weak λ-shaped anomaly at 483 ± 5 K, presumably associated with the well-known low-pressure P2₁/a ⇆ A2/a transition, in good agreement with previous studies. A value of 0.196 ± 0.007 kJ mol⁻¹ for the enthalpy of the P2₁/a ⇆ A2/a transition was determined by integration of the area under the curve for a temperature interval of 438–528 K, bracketing the anomaly. The heat capacity data for end-member titanite and (CaTiSiO₅) glass can be reproduced within <1% using the derived empirical equations (temperature in K, pressure in bars): The available enthalpy of vitrification (80.78 ± 3.59 kJ mol⁻¹), and the new heat capacity equations for solid and glass can be used to estimate (1) the enthalpy of fusion of end-member titanite (122.24 ± 0.2 kJ mol⁻¹), (2) the entropy of fusion of end-member titanite (73.85 ± 0.1 J/mol K⁻¹), and (3) a theoretical glass transition temperature of 1130 ± 55 K. The latter is in considerable disagreement with the experimentally determined glass transition temperature of 1013 ± 3 K. This discrepancy vanishes when either the adopted enthalpy of vitrification or the liquid heat content, or both, are adjusted. Calculations using Eq. (2), new P−V−T data for titanite, different but also internally consistent thermodynamic data for anorthite, rutile, and kyanite, and experimental data for the reaction: anorthite + rutile = titanite + kyanite strongly suggest: (1) the practice to adjust the enthalpy of formation of titanite to fit phase equilibrium data may be erroneous, and (2) it is probably the currently accepted entropy of 129.2 ± 0.8 J/mol K⁻¹ that may need revision to a smaller value. Received: 30 December 1999 / Accepted: 23 June 2000  相似文献   

The solar magnetic flux mid-term periodicities and the solar dynamo     

J.F. Valds-Galicia  A. Lara  B. Mendoza 《Journal of Atmospheric and Solar》2005,67(17-18):1697

We investigate here the fluctuations in the total, open and closed solar magnetic flux (SMF) for the period 1971–1999 by means of the maximum entropy method in the frequency range 5×10⁻⁹–10⁻⁷ Hz (6 yr to 120 days). We use monthly data for the total, open and closed magnetic solar fluxes. Periodicities found in the series are similar showing that there is some relationship between the fluxes. The most important finding of this work is the existence of fluctuations at around 1.3 and 1.7 yr in the SMF with alternating importance during consecutive even and odd solar cycles. These fluctuations are directly related with variations present in cosmic rays, solar wind parameters and geomagnetic activity indexes. A quasi-triennial periodicity previously found in sunspots and other solar phenomena is also of importance. The SMF is generated by the action of the solar dynamo; therefore, it is through the magnetic flux that the solar dynamo influences several heliospheric phenomena.  相似文献   

Some notes on entropy measures. II. The relative entropy matrix and the positivity constraint     

Ian Lerche 《Mathematical Geology》1989,21(8):843-852

Based on the maximum entropy concept with the number of bins (class intervals), N, maximized in terms of residual errors in sampling of the system, the residual entropy matrix (REM), which is intrinsically positive definite, is sampled uniformly at N equal intervals in entropy space. The mandatory constraint of positivity shows that the finitely sampled REM then provides estimates on the magnitudes of missing components of the autocorrelation sequence describing REM. If the mandatory constraint is relaxed to its limit, the resulting prediction for REM is identical to Burg's (1967) maximum entropy algorithm. The advantages are that assessments can be made: (i) whether the missing components are known accurately enough that no further measurements are needed; (ii) the N equal intervals of the entropy measure are sufficient to provide resolution on the REM for each and every sample; or (iii) whether finer interval resolution is needed to extract information for a particular sample.  相似文献   

宁夏倾斜固体潮潮汐因子熵的变化     

吴立辛  赵卫明  马禾青 《内陆地震》2000,14(3):207-212

应用宁夏银川台和石嘴山台倾斜固体潮观测数据计算了潮汐因子γ值,进一步计算了γ值的熵值,并对各熵值曲线进行分析,结果认为γ值熵在震前的异常表现比较突出,熵值变化到最低时,很有可能是应变积累到最大程度,即进入了临震状态。  相似文献