地震孕育过程的非线性动力学模型   总被引：4，自引：0，他引：4  

秦四清  张倬元 《中国地震》1994,10(3):223-229

本文提出了依据观测数据反演地震孕育过程的非线性动力学模型的方法，给出了可预报时间尺度的确定方法及系统稳定性判别准则，对唐山地震的分析表明，非线性动力学分析方法是行之有效的。  相似文献   

分形理论及其在地貌学中的应用──分形地貌学研究综述及展望   总被引：29，自引：1，他引：29  

张捷  包浩生 《地理研究》1994,13(3):104-112

本文简介了分形的有关基本概念,回顾了分形理论在海岸、流水、喀斯特地貌等多种地貌类型和流域地貌发育的形态研究中,以及在地貌过程研究中的应用的新近成果,并提出了今后分形地貌学研究的五个主要方面.  相似文献   

地震过程动力学行为和可预报性问题研究   总被引：4，自引：0，他引：4       下载免费PDF全文

胡平  杨培才 《地球物理学报》1990,33(6):647-656

本文提出了地震事件时序概念,找到了通过对实际地震观测资料的分析来有效地研究地震系统动力学行为和可预报性问题的方法.从实例分析观测资料的结果发现,被分析的这些地震系统混沌吸引子关联维数d₂为3.2-7.5,二阶Renyi熵K₂为0.019-0.052.这表明这些地震过程存在着已知变量数目范围的确定性规律,是可以预报的,但可预报时间有限.由K₂可以估算在一定预报精度要求下,对未来地震的可预报时间长度（本文震例中最长为一个月左右）.这套分析方法对认识地震过程动力学行为及可预报性问题都有重要意义.  相似文献   

PSO-PSR-ELM集成学习算法在地面气温观测资料质量控制中的应用   总被引：1，自引：0，他引：1  

张颖超  姚润进  熊雄  沈云培 《气候与环境研究》2017,22(1):59-70

针对台站密度低、新建台站以及特种单要素站等无法获得有效邻站或内部参考资料情况下的质量控制问题,从气温时间序列的混沌特性出发,考虑气温在短时间内的连续性和稳定性,提出一种基于粒子群(Particle Swarm Optimization,PSO)改进的相空间重构法(Phase Space Reconstruction,PSR)和极限学习机(Extreme Learning Machine,ELM)的集成学习算法的地面逐时气温观测资料的单站质量控制方法,实现气温资料的质量控制。为检验该方法的适用性,运用该方法对江苏省八市2007~2009年的地面气温观测资料进行质量控制,并与传统单站方法及切比雪夫多项式内插法(Tshebyshev Polynomial Interpolation,TPI)进行对比。实验结果表明,该方法相比较于TPI和传统方法可以更有效地标记出可疑数据,具有检错率高、地区和气候适应性、可控性强等优点。  相似文献   

新疆和田河流域河川径流混沌特性分析   总被引：2，自引：0，他引：2  

莫淑红  张高锋  沈冰  ZHANG Xiao-wei 《干旱区地理》2008,31(1):44-49

新疆和田河属冰川融雪及高山降水混合补给型河流,平原绿洲区降水基本不产流,其年径流主要受气温和山区降水影响,是塔里木河现今的四大源流之一。针对和田河流域和田河支流玉龙喀什河和喀拉喀什河,充分利用同古孜洛克水文站和乌鲁瓦提水文站1957-2002年共46年实测月径流时间序列所包含的丰富信息,采用自相关函数法选取延滞时间τ,重构了2条河流月径流序列的12维相空间,基于相空间重构,估算了能够表征水文系统混沌特性的定量指标即月径流序列的饱和关联维数D2和最大Lyapunov指数λ1,结果表明上述2条河流月径流序列存在相同的饱和关联维数且相关维数非整数,同时由资料所得的最大Lyapunov指数λ1也全部为正数,充分说明两条河流径流系统均存在混沌特性。  相似文献   

Periodic orbits and bifurcations in the Sitnikov four-body problem     

P. S. Soulis  K. E. Papadakis  T. Bountis 《Celestial Mechanics and Dynamical Astronomy》2008,100(4):251-266

We study the existence, linear stability and bifurcations of what we call the Sitnikov family of straight line periodic orbits in the case of the restricted four-body problem, where the three equal mass primary bodies are rotating on a circle and the fourth (small body) is moving in the direction vertical to the center mass of the other three. In contrast to the restricted three-body Sitnikov problem, where the Sitnikov family has infinitely many stability intervals (hence infinitely many Sitnikov critical orbits), as the “family parameter” ż₀ varies within a finite interval (while z ₀ tends to infinity), in the four-body problem this family has only one stability interval and only twelve 3-dimensional (3D) families of symmetric periodic orbits exist which bifurcate from twelve corresponding critical Sitnikov periodic orbits. We also calculate the evolution of the characteristic curves of these 3D branch-families and determine their stability. More importantly, we study the phase space dynamics in the vicinity of these orbits in two ways: First, we use the SALI index to investigate the extent of bounded motion of the small particle off the z-axis along its interval of stable Sitnikov orbits, and secondly, through suitably chosen Poincaré maps, we chart the motion near one of the 3D families of plane-symmetric periodic orbits. Our study reveals in both cases a fascinating structure of ordered motion surrounded by “sticky” and chaotic orbits as well as orbits which rapidly escape to infinity.  相似文献   

Chaos in cosmic ray air showers     

Takashi Kitamura  Soji Ohara  Takeharu Konishi  Katsufumi Tsuji  Michiyuki Chikawa  Wasaburo Unno  Isao Masaki  Kenji Urata  Yukihiro Kato 《Astroparticle Physics》1997,6(3-4):279-291

Unexpected chaotic features are found in time series of arrival time intervals of successive air showers with (E > 3 × 10¹⁴ eV). Over 99 % of air shower arrival time intervals obey the Poisson distribution law representing stochastic behaviors, but occasionally there are air showers showing real chaotic behaviors as distinguished from both random and colored noises. With two systems of the Kinki university installations, we found 13 cases showing chaotic time series in 3.36 yr with the system-1 and the 1.37 yr with the system-2. Five out of 10 chaotic air showers of the Kinki installation are detected during the same time zone also by the Osaka City university installation which is at 115 km distance from the Kinki one. In a remarkable example of September 19, 1991, the correlation dimension was observed to have dropped from about 4 to the minimum of 1.3 and recovered smoothly in about 38 h. The chaos structure in this case is detected in nearly the same time zone at the Ohya station of the Institute for Cosmic Ray Research, University of Tokyo, which is separated from the Kinki one by 460 km. Formation of chaos structure due to energetic cosmic ray dust particles is suggested. Progress of cosmic ray physics may be expected with the study of air showers marked with chaos.  相似文献   

Information entropy     

J. A. Núñez  P. M. Cincotta  F. C. Wachlin 《Celestial Mechanics and Dynamical Astronomy》1996,64(1-2):43-53

In this paper we present an indicator of chaos that takes advantage of the Information Entropy concept. We develop the mathematical formulation and test the results of its application with those obtained by other methods for the 2D Hénon-Heiles system and the 3D Contopoulos, Galgani and Giorgilli potential.  相似文献   

动力地貌过程与分形研究：以元谋盆地为例     

李先之 《云南地理环境研究》1994,6(2):87-95

文章认为动力地貌过程是个动态系统，处于混沌态，分形无处不在。为更好地进行地貌分形研究，作者引进复变函数和复平面作为计算机分形模拟的理论基础。该研究主要是在元谋盆地进行，作者在广泛野外勘测和室内计算机工作站精密跟踪、分析计算的基础上，提出元谋土林发育过程的复变函数表达式，并对其进行深入细致的分析模拟工作，得出部分形参意义，与地貌实体进行对照比较，结果较为理想。最后，文章反省该研究的缺陷与不足，提出存在的问题和今后的研究方向。  相似文献