A Non-Linear Dynamical–Statistical Model for Reconstruction of the Air–Sea Element Fields in the Tropical Pacific Ocean     

Mei Hong  Ren Zhang  Chen Chen Ma  Dong Wang  Chengzu Bai  Jingzhong Min 《大气与海洋》2014,52(3):256-270

Aiming at tackling the difficulty in establishing a sea surface temperature (SST) dynamical model, this study develops a non-linear dynamical–statistical model of SST fields and their correlative factors based on Genetic Algorithms (GA) and the dynamical system reconstruction idea, which greatly improves the El Niño–Southern Oscillation (ENSO) forecast model. Using Hadley SST data, sea surface wind (SSW) and sea level pressure (SLP) data from the National Centers for Environmental Prediction-National Center for Environmental Research (NCEP-NCAR), with empirical orthogonal function (EOF) time-space for reconstruction, we carry out numerical integral forecasting experiments for SST, SSW, and SLP fields. By statistical analysis of the forecasting experiments, we find that forecasts for less than 25 months perform better than longer term forecasts. Based on the model, we forecast SST, SSW, and SLP fields in September, October, and November 2014 and predict a weak La Niña event. This study explores a novel method for the complex atmosphere–ocean system.  相似文献   

基于GA-SIFT算法的无人机航拍图像实时拼接     

王艳  祁萌 《测绘通报》2021,(8):28-32,47

为实现无人机航拍图像的实时拼接,本文深入研究了无人机航拍图像拼接中的关键技术,提出了一种基于遗传算法优化的图像拼接算法。首先利用SIFT算法提取图像的特征点,在特征点粗匹配过程中,采用欧氏距离作为相似度测量,利用遗传算法的并行性优化特征点匹配性能;然后使用RANSAC算法去除误匹配点对并获得转换矩阵,从而完成图像拼接。试验结果表明,采用遗传算法进行特征匹配,可大大降低匹配时间,匹配时间与特征点数量成正比;同时提高了匹配精度,进而提高了图像拼接的实时性和稳健性。  相似文献   

Using a hybrid genetic algorithm–simulated annealing algorithm for fuzzy programming of reservoir operation     

Yu‐Chen Chiu  Li‐Chiu Chang  Fi‐John Chang 《水文研究》2007,21(23):3162-3172

We present a novel approach for optimizing reservoir operation through fuzzy programming and a hybrid evolution algorithm, i.e. genetic algorithm (GA) with simulated annealing (SA). In the analysis, objectives and constraints of reservoir operation are transformed by fuzzy programming for searching the optimal degree of satisfaction. In the hybrid search procedure, the GA provides a global search and the SA algorithm provides local search. This approach was investigated to search the optimizing operation scheme of Shihmen Reservoir in Taiwan. Monthly inflow data for three years reflecting different hydrological conditions and a consecutive 10‐year period were used. Comparisons were made with the existing M‐5 reservoir operation rules. The results demonstrate that: (1) fuzzy programming could effectively formulate the reservoir operation scheme into degree of satisfaction α among the users and constraints; (2) the hybrid GA‐SA performed much better than the current M‐5 operating rules. Analysis also found the hybrid GA‐SA conducts parallel analyses that increase the probability of finding an optimal solution while reducing computation time for reservoir operation. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

On the Application of a Genetic Algorithm to the Predictability Problems Involving "On-Off" Switches   总被引：2，自引：0，他引：2  

郑琴  戴毅  张露  沙建新  陆小庆 《大气科学进展》2012,29(2):422-434

The lower bound of maximum predictable time can be formulated into a constrained nonlinear opti- mization problem, and the traditional solutions to this problem are the filtering method and the conditional nonlinear optimal perturbation (CNOP) method. Usually, the CNOP method is implemented with the help of a gradient descent algorithm based on the adjoint method, which is named the ADJ-CNOP. However, with the increasing improvement of actual prediction models, more and more physical processes are taken into consideration in models in the form of parameterization, thus giving rise to the on-off switch problem, which tremendously affects the effectiveness of the conventional gradient descent algorithm based on the ad- joint method. In this study, we attempted to apply a genetic algorithm (GA) to the CNOP method, named GA-CNOP, to solve the predictability problems involving on-off switches. As the precision of the filtering method depends uniquely on the division of the constraint region, its results were taken as benchmarks, and a series of comparisons between the ADJ-CNOP and the GA-CNOP were performed for the modified Lorenz equation. Results show that the GA-CNOP can always determine the accurate lower bound of maximum predictable time, even in non-smooth cases, while the ADJ-CNOP, owing to the effect of on-off switches, often yields the incorrect lower bound of maximum predictable time. Therefore, in non-smooth cases, using GAs to solve predictability problems is more effective than using the conventional optimization algorithm based on gradients, as long as genetic operators in GAs are properly configured.  相似文献   

基于遗传算法(GA)的地应力有限元反演研究   总被引：1，自引：0，他引：1  

杨志双  潘懋 《水文地质工程地质》2006,33(2):80-83

由于地应力的反演是一个不断逼近最优解的过程，计算量较大，收敛速度较慢。为解决该问题，本文引入遗传算法确定地应力反演中的边界条件，从而提高收敛速度。本文利用改进的反演算法确定河北平原区的边界条件，并在此基础上采用有限元方法计算出该地区的地应力。结果表明，本文提出的算法计算速度快、且其计算结果与地震机制解及活动断裂的分布具有良好的一致性。  相似文献   

人工神经网络与遗传算法结合的时间序列预测模式   总被引：6，自引：1，他引：6  

赵远东  郭光 《南京气象学院学报》1997,20(3):375-381

介绍了遗传算法的基本概念和流程，阐述了人工神经网络作为时间序列预测模式的可行性和不足之处，并提出了人工网络与遗传算法相结合的时间序列预测模式，最后给出了该算法的计算结果，并对结果和模式作了讨论。  相似文献   

TIMESERIES PREDICTION MODEL CONSISTING OF ARTIFICIAL NEURAL NETWORK AND GENETIC ALGORITHM     

郭光  YanShaojin  严绍瑾  金龙 《Acta Meteorologica Sinica》1998,(2)

The paper introduces the basic concept and flow diagram of genetic algorithm (GA) and themerits and demerits of artificial neural network (ANN) as a timeseries prediction model andthereupon developed is a new model with ANN and GA in combination. Eventually, calculationsare presented with the results and model examined.  相似文献   

用改进的遗传算法对密集平行地下管线直接反演的研究     

曹立斌  鲁永康  周建兰 《物探化探计算技术》2003,25(4):358-362

密集平行管线探测资料解释是管线探测技术中的一大难题，至今没有很好地解决。用改进的遗传算法来直接反演密集平行管线的地下参数(平面位置、埋深)，可取得良好的效果，同时也显示了遗传算法的优越性。  相似文献   

Sensitivity analysis of submersibles’ manoeuvrability and its application to the design of actuator inputs     

Dong Jin Yeo  Key Pyo Rhee 《Ocean Engineering》2006,33(17-18):2270-2286

The influences of hydrodynamic coefficients on the prediction of manoeuvrability were examined by sensitivity analysis (SA) of direct method. The equations of motion used were the standard equations of motion for submarine [Gertler, M., Hagen, G.R., 1967. Standard equations of motion for submarine simulation. DTNSRDC Report], and three submersibles with different appendages were considered. Numerical simulations of three types of sea trials are performed to obtain the sensitivities of motions to hydrodynamic coefficients. Since the accuracy of hydrodynamic coefficients’ estimates is increased by the use of sensitivity-maximizing inputs, the sensitivity-optimal actuator commands that are sequences of bang-bang type inputs were deduced with genetic algorithm (GA) optimization technique.  相似文献   

羧甲基壳聚糖水凝胶制备及在药物控释中的应用   总被引：8，自引：0，他引：8  

徐甲坤  毕彩丰  范玉华  郭锋  何雪涛  刘冬雪 《中国海洋大学学报(自然科学版)》2007,37(3):503-506

研究羧甲基壳聚糖水凝胶(CMCS-GA)对阿司匹林的吸附性能及其在药物控释系统中的应用。以羧甲基壳聚糖作为骨架材料,采用戊二醛交联法制备CMCS-GA,进而制备阿司匹林载药凝胶。测定凝胶在人工肠液中的溶胀动力学特点,观察载药凝胶在人工肠液中的体外释放行为。在pH=7.4的人工肠液中CMCS-GA 2 h达最大溶胀度1.38。CMCS-GA的载药量为4.6 mg/g,凝胶在人工肠液中96 h的累积释放度为99.91%,具有优良的缓释性能,药物的体外释放模型符合一级动力学方程。  相似文献