An improved shuffled frog leaping algorithm and its application in the optimization of cascade reservoir operation     

Rongbo Li  Anqiang Li  Shan Yu  Changming Ji 《水文科学杂志》2013,58(15-16):2020-2034

ABSTRACT

A new improved shuffled frog leaping algorithm (SFLA), the chaos catfish effect SFLA (CCESFLA), is proposed by coupling a local “refine search” mechanism and a “global incentive adjustment” mechanism. Chaotic technology is introduced in the local “refine search” mechanism to improve local search ability, by implementing more refined local search around the optimal individuals. The catfish effect mechanism is adopted in the “global incentive adjustment” mechanism to improve global convergence, by motivating the frogs to “jump out” of the local steady state. The operation optimization by the CCESFLA is carried out taking the Li Xianjiang cascade reservoirs in China as an example. Compared with SFLA, particle swarm optimization, immune SFLA and cloud SFLA, the average annual power generation using the CCESFLA can be increased by 6.7, 7.5, 3.0 and 0.8%, respectively. The convergence process of the CCESFLA is more stable, and its execution time is the least of the three improved SFLAs.  相似文献   

带电测试粒子在磁化史瓦西黑洞中的混沌运动          下载免费PDF全文

周娜英  张洪星  孙鑫  刘文芳  李丹 《天文学报》2023,64(4):39

当史瓦西黑洞周围存在渐近均匀的外部磁场时, 描述带电粒子在史瓦西黑洞附近运动的哈密顿系统会变为不可积系统. 类似于这样的相对论哈密顿系统不存在有显式分析解的2部分分离形式, 给显式辛算法的构建和应用带来困难. 近一年以来的系列工作提出将相对论哈密顿系统分解为具有显式分析解的2个以上分离部分形式, 成功解决了许多相对论时空构建显式辛算法的难题. 最近的工作回答了哈密顿系统显式可积分离数目对长期数值积分精度有何影响、哪种显式辛算法有最佳长期数值性能这两个问题, 指出哈密顿有最小可积分离数目即3部分分裂解形式并且应用于优化的4阶分段龙格库塔显式辛算法可取得最好精度. 由此选择上述数值积分方法并利用庞加莱截面、最大李雅普诺夫指数和快速李雅普诺夫指标研究在磁化史瓦西黑洞附近运动的带电粒子轨道动力学. 结果显示: 针对某特定的粒子能量和角动量, 较小的外部磁场很难形成混沌轨道; 较大的正磁场参数容易使轨道产生混沌, 并且随着磁场的增大, 轨道的混沌程度也随之加强; 粒子能量适当变大也可以加剧混沌程度, 但负磁场参数和粒子角动量变大都会减弱混沌.  相似文献   

地闪不规则先导的多尺度熵特征   总被引：2，自引：2，他引：0       下载免费PDF全文

李婵  张阳  吕伟涛  郑栋  谭涌波 《应用气象学报》2014,25(3):347-353

针对不规则脉冲簇难以判别问题,将多尺度熵应用于不规则先导分析中,探讨闪电信号不规则脉冲分析应用中多尺度熵关键参量的选择方法。在此基础上,将不规则先导与直窜先导及梯级先导闪电信号的多尺度熵进行比较。统计分析表明:不规则先导和直窜先导熵值随尺度先增加后趋于平稳,但熵值有很大差异;梯级先导熵值随尺度变化不明显,整体呈增长趋势,与不规则先导的熵值在大于3的尺度上也有所差异,因此当尺度大于3时可将熵值大于1.5的先导归类为不规则先导,熵值小于1.5的先导归类为梯级先导或直窜先导。不规则先导的特征熵平均值为2.0~2.1,最大值范围为2.6~2.8,最小值范围为1.51~1.59。  相似文献   

Evidence of chaos in the rainfall-runoff process     

BELLIE SIVAKUMAR  RONNY BERNDTSSON  JONAS OLSSON  KENJI JINNO 《水文科学杂志》2013,58(1):131-145

Abstract

The transformation of rainfall into runoff is one of the most important processes in hydrology. In the past few decades, a wide variety of automated or computer-based approaches have been applied to model this process. However, many such approaches have an important limitation in that they treat the rainfall-runoff process as a realization of only a few parameters of linear relationships rather than the process as a whole. What is required, therefore, is an approach that can capture not only the overall appearance but also the intricate details of the nonlinear behaviour of the process. The purpose of this study is to investigate the possibility of understanding the dynamics of the rainfall-runoff process from a new perspective, as a chaotic process. The possible existence of chaotic behaviour in the rainfall-runoff process is studied by investigating the rainfall and runoff time series: (a) separately; and (b) jointly (using the runoff coefficient). Monthly rainfall and runoff observed over a period of 131 years (January 1807-December 1937) at the Göta River basin in the south of Sweden are analysed. The correlation dimension method is employed to identify the presence of chaos. The correlation dimensions obtained for the rainfall and runoff time series are 6.4 and 5.5, respectively. The finite dimensions obtained for the rainfall and runoff time series indicate the possible existence of chaos in these processes, implying that the joint rainfall-runoff process might also exhibit chaotic behaviour. The correlation dimension of about 7.8 obtained for the runoff coefficient also indicates the possible presence of chaos and supports the above results.  相似文献   

噪声通过混沌振子后统计特性的定性分析     

李月  郭华  唐方江  邓晓英  刘奔 《吉林大学学报(地球科学版)》2002,32(3):287-289

混沌振子对小信号的敏感性以及对噪声的免疫力，使它可以应用于微弱信号的检测。根据随机微分方程理论，对噪声经过混沌振子后的统计特性进行了定性分析，得出输出噪声为非平稳过程，而且该过程为循环平衡过程的结论，为实际应用提供理论指导。  相似文献   

基于神经网络的混沌时间序列预测   总被引：8，自引：0，他引：8  

许传华  任青文  房定旺 《水文地质工程地质》2003,30(1):30-32

应用混沌方法对时间序列观测数据进行处理,计算出最大lyapunov指数,得到最大可预报时间尺度。在此基础上,建立人工神经网络预测预报混沌时间序列的模型。结合实例,对该预测方法进行了计算验证。  相似文献   

从时（空）系列数据研究地球化学作用的非线性动力学     

谭凯旋  张哲儒  刘荣高 《矿物岩石地球化学通报》1996,(2)

从时（空）系列数据研究地球化学作用的非线性动力学谭凯旋（中国科学院长沙大地构造研究所．长沙４１００１３）张哲儒，刘荣高（中国科学院地球化学研究所．贵阳５５０００２）关键词混沌吸引子，分维，时（空）系列数据，地球化学动力学近十多年来，人们已认识到地球化...  相似文献   

Motion near the 3/1 resonance of the planar elliptic restricted three body problem     

Jacques Henrard  N.D. Caranicolas 《Celestial Mechanics and Dynamical Astronomy》1989,47(2):99-121

The global semi-numerical perturbation method proposed by Henrard and Lemaître (1986) for the 2/1 resonance of the planar elliptic restricted three body problem is applied to the 3/1 resonance and is compared with Wisdom's perturbative treatment (1985) of the same problem. It appears that the two methods are comparable in their ability to reproduce the results of numerical integration especially in what concerns the shape and area of chaotic domains. As the global semi-numerical perturbation method is easily adapted to more general types of perturbations, it is hoped that it can serve as the basis for the analysis of more refined models of asteroidal motion. We point out in our analysis that Wisdom's uncertainty zone mechanism for generating chaotic domains (also analysed by Escande 1985 under the name of slow Hamiltonian chaotic layer) is not the only one at work in this problem. The secondary resonance _p = 0 plays also its role which is qualitatively (if not quantitatively) important as it is closely associated with the random jumps between a high eccentricity mode and a low eccentricity mode.  相似文献   

Fourier analysis of local Lyapunov characteristic exponents for satellite-type motions     

E. Lohinger  C. Froeschlé 《Celestial Mechanics and Dynamical Astronomy》1993,57(1-2):369-372

For a binary star system with equal masses the transition from regular to stochastic motion has been determined by means of the Lyapunov Characteristic Numbers (LCN) in a paper of Gonczi and Froeschlé (1981), where the initial distance of the massless body to the second primary was used as parameter of integration. This time we analyse the Fourier spectra of the local LCNs (ln _k ⁱ ) of this system for different intervals of time.  相似文献   

控制太阳活动的混沌吸引子(英)     

张勤 《天文学进展》1998,(1)

随着非线性科学研究的进展,可利用表征太阳活动的太阳活动指数组成的时间序列来寻找或许存在的太阳混沌吸引子,并计算其关联维数、最大Lyapunov指数以及其它特征量．文中综述了用非线性科学的某些概念来研究太阳活动的进展及其在太阳活动预报方面的一些应用．  相似文献