Why do Trojan ASCs (not) Escape?     

Rudolf Dvorak  Kleomenis Tsiganis 《Celestial Mechanics and Dynamical Astronomy》2000,78(1-4):125-136

The orbits of 12 Trojan asteroids, which have Lyapunov times T _L10⁵ years and were previously classified as ASCs(=asteroids in stable chaos), are integrated for 50 Myrs, along with a group of neighbouring initial conditions for each nominal orbit. About 40% of the orbits present strong instabilities in the inclination, which may be attributed primarily to the action of the ₁₆ secular resonance; two escapes are also recorded. Higher-order secular resonances, involving the nodes of the outer planets, are also found to be responsible for chaotic motion. Orbital stability depends critically on the choice of initial conditions and, thus, these objects can be regarded as being on the edge of strong chaos.  相似文献   

The two-body problem with radiation pressure in a rotating reference frame     

Harry Dankowicz 《Celestial Mechanics and Dynamical Astronomy》1995,61(3):287-313

We study a perturbed Newtonian two-body problem, in which the perturbation is due to a force field of constant magnitude but rotating direction. By considering this system as a perturbation of the non-rotating case a Melnikov-type analysis allows us to show the existence of horseshoes in the level sets of the Hamiltonian and the subsequent sensitive dependence on initial conditions and non-integrability. We discuss the consequences of these results for a particular planar restricted three-body problem.Supported by a grant from the Royal Swedish Academy of Sciences and AFOSR NM 91-0329.  相似文献   

混沌映射在优化计算中的应用   总被引：3，自引：0，他引：3  

郑肇葆 《武汉大学学报(信息科学版)》2007,32(11):998-1000

利用描述混沌运动的Logisdc方程的随机性取代常规的均匀分布的随机数发生器的随机性，并应用在产生“Tuned”模板的优化过程中，得到了最佳模板。经实际航空影像的试验表明，Logistic映射的引用可使模板用于影像纹理识别的性能有所提高。  相似文献   

混沌免疫算法在遥感影像分类中的应用研究     

武彦斌  黄明 《测绘工程》2007,16(1):55-58

为提高遥感影像分类精度,采用基于混沌免疫算法(Chaos Immune Algorithm)的分类方法。利用混沌优化的遍历性,进行粗粒搜索,优化初始抗体群;通过选择算子、克隆算子、变异算子、抗体的循环补充等操作,得到全局最优的聚类中心,提高分类精度。实验表明该方法分类总精度、Kappa系数均优于传统分类方法。  相似文献   

WRF-EnKF系统对中国南方一次暴雨过程确定性预报的试验   总被引：1，自引：0，他引：1  

宝兴华  杨舒楠 《气象》2015,41(5):566-576

文章利用美国宾州州立大学的WRF EnKF(Ensemble Kalman Filter)实时预报系统(Real time Penn State WRF EnKF System),针对2013年5月15—16日发生在中国南方的暴雨过程进行了数值预报试验,以初步检验该系统对我国南方降水确定性预报的效果。数值试验采用2013年5月14日08时（北京时）起报的6 h间隔的1°×1° NCEP GFS (globle forecast system) 60 h预报数据（预报到5月16日20时）作为初始条件和边界条件。其中,控制试验不同化任何观测资料,同化试验通过集合卡尔曼滤波方法同化常规探空资料,分别进行确定性预报。结果表明：利用WRF EnKF系统同化常规探空资料,显著改善了数值预报的初始场,减小了各物理量的预报偏差和预报均方根误差,进而提高了此次暴雨过程的降水落区和强度的预报准确率。  相似文献   

Study of resonances for the restricted 3‐body problem     

B. Quarles  Z.E. Musielak  M. Cuntz 《Astronomische Nachrichten》2012,333(7):551-560

Our aim is to identify and classify mean‐motion resonances (MMRs) for the coplanar circular restricted three‐body problem (CR3BP) for mass ratios between 0.10 and 0.50. Our methods include the maximum Lyapunov exponent, which is used as an indicator for the location of the resonances, the Fast Fourier Transform (FFT) used for determining what kind of resonances are present, and the inspection of the orbital elements to classify the periodicity. We show that the 2:1 resonance occurs the most frequently. Among other resonances, the 3:1 resonance is the second most common, and furthermore both 3:2 and 5:3 resonances occur more often than the 4:1 resonance. Moreover, the resonances in the coplanar CR3BP are classified based on the behaviour of the orbits. We show that orbital stability is ensured for high values of resonance (i.e., high ratios) where only a single resonance is present. The resonances attained are consistent with the previously established resonances for the solar system, i.e., specifically, in regards to the asteroid belt. Previous work employed digital filtering and Lyapunov characteristic exponents to determine stochasticity of the eccentricity, which is found to be consistent with our usage of Lyapunov exponents as an alternate approach based on varying the mass ratio instead of the eccentricity. Our results are expected to be of principal interest to future studies, including augmentations to observed or proposed resonances, of extra‐solar planets in binary stellar systems (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

复杂性科学在页岩油气勘探和研究中的应用          下载免费PDF全文

于炳松  阮壮 《地质论评》2022,68(5):2022102012-2022102012

复杂性科学是当今世界科学重要的前沿领域之一。为了促进复杂性科学的基本理论和方法在页岩油气勘探和研究领域的广泛应用，笔者等重点围绕地质系统复杂性的基本内涵，从地质系统构成单元的多重耦合和相互作用、地质作用的复杂时空结构、地质作用过程中的自组织临界过程动力学以及矿产资源形成在混沌边缘等方面，介绍了地质系统复杂性研究的基本理论和研究方法。将上述地质系统复杂性理论运用于页岩油气系统，探讨了利用复杂系统的总体特征通过局域组成单元相互作用的“涌现”机制，来解决目前页岩储层中存在的如何利用微观局域精细表征进行客观刻画宏观储层特征问题；分析了利用地质作用的时空结构理论，建立页岩储层非均质性的静态和分形时空结构的方法；在整体论思想指导下，根据地质系统在混沌边缘分形生长这一规律，探讨了页岩油气在自组织临界态的混沌边缘富集预测方法。复杂性科学的理论和方法，必将在页岩油气的勘探研究中发挥越来越重要的作用。  相似文献