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1.
Nonlinear Time Series Analysis Since 1990:Some Personal Reflections   总被引:5,自引:0,他引:5  
Abstract I reflect upon the development of nonlinear time series analysis since 1990 by focusing on five majorareas of development. These areas include the interface between nonlinear time series analysis and chaos,thenonparametric/semiparametric approach,nonlinear state space modelling,financial time series and nonlinearmodelling of panels of time series.  相似文献
2.
共轭算子法和非线性动力系统的高阶规范形   总被引:4,自引:0,他引:4  
规范形理论是研究非线性动力系统退化分含的强有力的方法.在本文里我们利用共轭算子法计算了具有幂零线性部分和不具有Z2-对称性的非线性动力系统的2阶、3阶和4阶规范形,讨论了几种余维3退化分含情况下的普适开析问题及其一些全局特性.  相似文献
3.
Direct and indirect methods for trajectory optimization   总被引:4,自引:0,他引:4  
This paper gives a brief list of commonly used direct and indirect efficient methods for the numerical solution of optimal control problems. To improve the low accuracy of the direct methods and to increase the convergence areas of the indirect methods we suggest a hybrid approach. For this a special direct collocation method is presented. In a hybrid approach this direct method can be used in combination with multiple shooting. Numerical examples illustrate the direct method and the hybrid approach.  相似文献
4.
二维非线性动力系统的多极限环分叉的参数控制   总被引:3,自引:0,他引:3  
李静  缪素芬 《数学杂志》2005,25(6):695-700
本文研究了一类具有Z2-等变性质的5次扰动平面Hamilton向量场,利用动力系统的分叉理论和判定函数法,通过控制其参数,得到系统在两组不同的参数条件下分别存在20和23个极限环,以及它们之间相对位置的不同构型.这一结果对机械振动中相应的控制问题有理论指导意义。  相似文献
5.
Scatter search for chemical and bio-process optimization   总被引:3,自引:1,他引:2  
Scatter search is a population-based method that has recently been shown to yield promising outcomes for solving combinatorial and nonlinear optimization problems. Based on formulations originally proposed in 1960s for combining decision rules and problem constraints such as the surrogate constraint method, scatter search uses strategies for combining solution vectors that have proved effective in a variety of problem settings. In this paper, we develop a general purpose heuristic for a class of nonlinear optimization problems. The procedure is based on the scatter search methodology and treats the objective function evaluation as a black box, making the search algorithm context-independent. Most optimization problems in the chemical and bio-chemical industries are highly nonlinear in either the objective function or the constraints. Moreover, they usually present differential-algebraic systems of constraints. In this type of problem, the evaluation of a solution or even the feasibility test of a set of values for the decision variables is a time-consuming operation. In this context, the solution method is limited to a reduced number of solution examinations. We have implemented a scatter search procedure in Matlab (Mathworks, 2004) for this special class of difficult optimization problems. Our development goes beyond a simple exercise of applying scatter search to this class of problems, but presents innovative mechanisms to obtain a good balance between intensification and diversification in a short-term search horizon. Computational comparisons with other recent methods over a set of benchmark problems favor the proposed procedure.  相似文献
6.
正规形的复内积平均法   总被引:2,自引:0,他引:2  
提出了求解非线性动力系统正规形的复内积平均法,与传统的平均法相比,其理论分析过程具有更加简单的形式,易于编程实现,可求到任意阶近似,并统一了自治系统与非自治系统的求解过程,最后求解一个例题来验证了该方法  相似文献
7.
系统探讨了种间制约作用的二维非线性动力系统的机理与过程,从生物力学角度扩展了Lotka—Volterra模型,建立了包含种间作用与反作用的二维非线性自治、非自治动力系统新模型,分析了该动力系统平衡点的稳定性、周期解的存在性与稳定性,并对其动力学过程进行了数值模拟试验研究.结果表明两生物种群间作用效率的大小、作用系数与反作用系数变化的同向与异向性和作用力时变等对动力系统稳定性都有一定影响,种间作用效率变大或变小,以及作用系数与反作用系数的异向变化都导致动力系统的不稳定,致使两种生物难以生存,而相互作用力时变则对系统的稳定起促进作用.  相似文献
8.
非线性弹性梁在谐波激励下的次谐和超次谐响应   总被引:1,自引:0,他引:1  
本文研究受横向周期载荷作用的梁的动力响应,梁的本构关系具有三次非线性项· 轴向载荷作用下已屈曲的梁受到横向激励后,谐波是不稳定的,将分叉出次谐波、超次谐波,以Melnikov法确定了次谐轨道、超次谐轨道产生的条件·  相似文献
9.
In this study, a novelty mathematical model is established to formulate the continuous culture of glycerol to 1,3-Propanediol (1,3-PD) by Klebsiella pneumoniae, in which the inhibition of 3-hydroxypropionaldehyde (3-HPA) to cells growth and activity of some enzymes (such as glycerol dehydratase (GDHt) and 1,3-PD oxidoreductase (PDOR)), and the passive diffusion and active transport of glycerol and 1,3-PD across cell membrane are all taken into consideration. Taking the mean relative error between the experimental data and calculated values as the performance index, a parameter identification model involving multiple nonlinear dynamic systems is presented. The identifiability of the parameter identification model is also proved. Finally, an improved particle swarm optimization (PSO) algorithm is constructed to find the optimal parameters for the systems under substrate limitation and excess conditions, respectively. Numerical results not only show that the established model can be used to describe the continuous fermentation reasonably, but also the improved PSO algorithm is valid.  相似文献
10.
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