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1.
针对复杂函数的数值积分求解问题,提出一种基于不等距点分割的差分进化算法.该算法在积分区域中选取一些个体,并利用差分进化算法对其进行优化,通过将函数变化较快的区间分得较细,函数变化较慢的区间分得较粗,得到较准确的数值积分.数值计算结果证明,该算法可以快速计算通常意义下任意函数的定积分,并能计算振荡函数的积分.  相似文献   

2.
提出了一种基于粒子群算法的不等距节点数值积分方法,该方法初始时在矩形积分区域两个方向的区间内各自任意选取一定的节点,通过粒子群算法优化这些节点,以优化后的节点为分割点求数值积分的值,最后得到比较精确的积分结果.数值积分算例表明,该算法得到的积分值精度高,自适应强,是一种有效的数值积分方法,在数值计算和工程实际应用中具有一定的参考和应用价值.  相似文献   

3.
基于进化策略方法求任意函数的数值积分   总被引:2,自引:0,他引:2  
周永权  张明  赵斌 《计算机学报》2008,31(2):196-206
提出了两种基于进化策略求任意函数数值积分的新方法,其中方法一是基于混合基函数进化策略的数值积分算法;方法二是基于不等距点分割的进化策略数值积分算法.两种算法都采用适用于高维优化问题的单基因突变进化策略,使得该算法不但能计算通常意义下任意函数的定积分,而且能计算奇异函数积分和振荡函数积分.最后给出几个数值积分算例,并与传统数值积分方法作了比较,仿真结果分析表明,两种算法十分有效,能够快速有效地获得任意函数的数值积分值.  相似文献   

4.
提出了一种基于进化策略算法的广义积分计算新方法,该方法根据被积函数的变量区间任意选取分割点,作为进化策略的初始的群体,通过进化策略算法来优化这些分割点,最终可得到一些最优的分割点,然后再求和,再根据和函数定义适应度函数,在给定的终止条件下,可获的精度较高的积分值.最后,以广义积分(无穷积分),二重广义积分(瑕积分)为例,仿真结果表明,该算法相比传统的一些方法,具有计算精度高,自适应性强等特点.  相似文献   

5.
蝙蝠算法具有收敛速度快、潜在分布式和并行性等特点,但也存在着寻优精度不高、后期收敛速度慢、易陷入局部最优等问题。针对蝙蝠算法和目前数值积分方法的不足,把具有很强的全局寻优能力和局部搜索能力的差分进化算法融合到蝙蝠算法中,提出了一种基于差分进化算法的改进蝙蝠算法求任意函数数值积分的新方法,该算法不仅能求解通常意义下任意函数的定积分,而且能计算振荡积分和奇异积分。通过6个不同算例与当前数值积分方法比较,实验仿真结果表明,该算法是有效的和可行的,能够快速有效地获取任意函数的数值积分值。同时,扩展了蝙蝠算法的应用领域。  相似文献   

6.
提出了一种基于泛函网络求教值积分新方法,给出了一种泛函网络模型及学习算法,并将该模型用于求任意函数的数值积分,理论上证明了泛函网络用于逼近数值积分定理.最后通过5个数值积分算例,并与传统计算方法作了比较分析,仿真结果表明,提出的数值积分方法精度高,适应性强,且不需要确定被积函数的原函数,因此该方法在工程技术中有较大的应用价值.  相似文献   

7.
传统计算二重积分方法大都是等距分割方法,但是在在被积函数区间变化快慢相差较大时,计算精度大为降低。为此,提出一种不等距点分割的差分进化算法用于求解复杂函数的二重积分问题。在积分区域x向与y向上选取一些节点,将积分区域分割成很多小的子矩形域,并通过差分进化算法对其进行优化,使函数变化较快的区域分得小一些,函数变化较慢的区域分得大一些,从而得到较准确的二重积分。仿真结果表明,提出的算法收敛速度快,计算精度高,能计算较复杂的二重积分。  相似文献   

8.
在分析传统求数值积分和基本人工鱼群算法不足的基础上,提出了一种基于人工鱼群算法的优化分割数值积分算法,该算法不仅能求解通常意义下函数的数值积分,还能计算奇异函数的数值积分。通过算例与传统数值积分方法比较,实验结果表明该算法是可行的和有效的。  相似文献   

9.
研究了带有区间时滞的不确定系统的稳定性问题。通过采用时滞分割法,把时滞区间分割成任意两小段,并构造恰当的Lyapunov函数,利用积分不等式,得到了新的时滞相关的稳定性准则。通过数值例子验证了结果的有效性。  相似文献   

10.
研究Volterra型积分方程的Galerkin Legendre Jacobi数值积分方法.首先,利用Jacobi Galerkin数值积分对方程中的积分项进行离散,从而我们得到一个等价方程.其次,对该等价模型构造Legendre Galerkin方程,且在积分项部分用Chebyshev插值计算.然后,该方法还被推广到非线性Volterra积分方程的计算.最后,对计算区间较大的模型,基于上述方法,构造了两级多区域格式且将其应用于含有一个间断点的Volterra型积分方程的计算.此外,还将其推广到第三类Volterra积分方程.通过数值算例验证该方法的高阶精度与有效性.  相似文献   

11.
A method of numerical solution of singular integral equations of the first kind with logarithmic singularities in their kernels along the integration interval is proposed. This method is based on the reduction of these equations to equivalent singular integral equations with Cauchy-type singularities in their kernels and the application to the latter of the methods of numerical solution, based on the use of an appropriate numerical integration rule for the reduction to a system of linear algebraic equations. The aforementioned method is presented in two forms giving slightly different numerical results. Furthermore, numerical applications of the proposed methods are made. Some further possibilities are finally investigated  相似文献   

12.
In this paper, the concept of multiple‐attribute group decision‐making (MAGDM) problems with interval‐valued Pythagorean fuzzy information is developed, in which the attribute values are interval‐valued Pythagorean fuzzy numbers and the information about the attribute weight is incomplete. Since the concept of interval‐valued Pythagorean fuzzy sets is the generalization of interval‐valued intuitionistic fuzzy set. Thus, due the this motivation in this paper, the concept of interval‐valued Pythagorean fuzzy Choquet integral average (IVPFCIA) operator is introduced by generalizing the concept of interval‐valued intuitionistic fuzzy Choquet integral average operator. To illustrate the developed operator, a numerical example is also investigated. Extended the concept of traditional GRA method, a new extension of GRA method based on interval‐valued Pythagorean fuzzy information is introduced. First, utilize IVPFCIA operator to aggregate all the interval‐valued Pythagorean fuzzy decision matrices. Then, an optimization model based on the basic ideal of traditional grey relational analysis (GRA) method is established, to get the weight vector of the attributes. Based on the traditional GRA method, calculation steps for solving interval‐valued Pythagorean fuzzy MAGDM problems with incompletely known weight information are given. The degree of grey relation between every alternative and positive‐ideal solution and negative‐ideal solution is calculated. To determine the ranking order of all alternatives, a relative relational degree is defined by calculating the degree of grey relation to both the positive‐ideal solution and negative ideal solution simultaneously. Finally, to illustrate the developed approach a numerical example is to demonstrate its practicality and effectiveness.  相似文献   

13.
Engineering fuzzy heat conduction problem with subjective uncertainties in input parameters constitutes a significant challenge. Based on fuzzy and interval theory, this paper presents novel numerical methods to efficiently identify the effect of fuzzy uncertainty on the system reliability analysis and optimization design. Firstly using the interval ranking strategy, the interval safety possibility in the transition state can be precisely quantified, and the eventual fuzzy safety possibility is calculated by integral operation. Then a fuzzy reliability-based optimization model is established with considerable computational cost caused by the two-layer nested loop. In order to improve the computational efficiency, a subinterval perturbation method based on the first-order Taylor series is presented to replace the inner loop. Comparing numerical results with traditional reliability model, two numerical examples are provided to evidence the superiority of proposed model and method for fuzzy reliability analysis and optimization in practical engineering.  相似文献   

14.
The problem of optimizing truss structures in the presence of uncertain parameters considering both continuous and discrete design variables is studied. An interval analysis based robust optimization method combined with the improved genetic algorithm is proposed for solving the problem. Uncertain parameters are assumed to be bounded in specified intervals. The natural interval extensions are employed to obtain explicitly a conservative approximation of the upper and lower bounds of the structural response, and hereby the bounds of the objective function and the constraint function. This way the uncertainty design may be performed in a very efficient manner in comparison with the probabilistic analysis based method. A mix-coded genetic algorithm (GA), where the discrete variables are coded with binary numbers while the continuous variables are coded with real numbers, is developed to deal with simultaneously the continuous and discrete design variables of the optimization model. An improved differences control strategy is proposed to avoid the GA getting stuck in local optima. Several numerical examples concerning the optimization of plane and space truss structures with continuous, discrete or mixed design variables are presented to validate the method developed in the present paper. Monte Carlo simulation shows that the interval analysis based optimization method gives much more robust designs in comparison with the deterministic optimization method.  相似文献   

15.
A simple noniterative method for the numerical determination of one simple root of a nonlinear differentiable algebraic or transcendental function along a finite real interval is proposed. This method is based on the computation of an integral involving the above function both by the Gauss- and the Lobatto-Chebyshev quadrature rules for regular integrals and equating the obtained results. The convergence of the method is proved under mild assumptions and numerical results for two classical transcendental equations are presented.  相似文献   

16.
A neuro-genetic controller for nonminimum phase systems.   总被引:1,自引:0,他引:1  
This paper investigates a neurocontroller for nonminimum phase systems which is trained off-line with genetic algorithm (GA) and is combined in parallel with a conventional linear controller of proportional plus integral plus derivative (PID) type. Training of this kind of a neuro-genetic controller provides a solution under a given global evaluation function, which is devised based on the desired control performance during the whole training time interval. Empirical simulation results illustrate the efficacy of the proposed controller compared with a conventional linear controller in point of learning capability of adaptation and improvement of performances of a step response like fast settling time, small undershoot, and small overshoot.  相似文献   

17.
In this paper, we consider the problem of approximating a function by Bernstein-type polynomials that preserve the integral and non-negativity of the original function on the interval [0, 1], obtaining the Kantorovich–Bernstein polynomials, but providing a novel approach with advantages in numerical analysis. We then develop a Markov finite approximation method based on piecewise Bernstein-type polynomials for the computation of stationary densities of Markov operators, providing numerical results for piecewise constant and piecewise linear algorithms.  相似文献   

18.
Topology optimization of phononic crystals (PnCs) is generally based on deterministic models without considering effects of inherent uncertainties existed in PnCs. However, uncertainties presented in PnCs may significantly affect band gap characteristics. To address this, an interval Chebyshev surrogate model-based heuristic algorithm is proposed for topology optimization of PnCs with uncertainties. Firstly, the interval model is introduced to handle the uncertainties, and then the interval Chebyshev surrogate model (ICSM), in which the improved fast plane wave expansion method (IFPWEM) is used to calculate the integral points to construct the ICSM, is introduced for band structure analysis with uncertainties efficiently. After that, the sample data, which is randomly generated by the Monte Carlo method (MCM), is applied to the ICSM for predicting the interval bounds of the band structures. Finally, topology optimization of PnCs is conducted to generate the widest band gaps with uncertainties included by utilizing the genetic algorithm (GA) and the ICSM. Numerical results show the effectiveness and efficiency of the proposed method which has promising prospects in a range of engineering applications.  相似文献   

19.
针对基于熵理论的贝叶斯信息融合技术需要进行无穷区间的积分运算,容易出现数值不稳定的问题,提出一种基于随机自适应方法的多传感器融合算法。利用传感器测量值之间的差值自适应地建立传感器的后验概率分布模型;结合互信息的理论实时识别和剔除伪测量值,避免求熵时的积分计算;将该方法分别应用于集中式融合方案和分布式融合方案中得到了两种新的数据融合方法。仿真实验结果表明,在存在伪测量值的情况下,该算法性能明显优于一般的贝叶斯融合方法。  相似文献   

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