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991.
Parameter Estimation for the Discretely Observed Vasicek Model with Small Fractional Lévy Noise 下载免费PDF全文
The statistical inference of the Vasicek model driven by small Levy process has a long history.In this paper,we consider the problem of parameter estimation for Vasicek model dX_t=(μ-θX_t)dt+εdL_t^d,t∈[0,1],X_0=x_0,driven by small fractional Lévy noise with the known parameter d less than one half,based on discrete high-frequency observations at regularly spaced time points{t_i=i/n,i=1,2,...,n}.For the general case and the null recurrent case,the consistency as well as the asymptotic behavior of least squares estimation of unknown parametersμandθhave been established as small dispersion coefficientε→0 and large sample size n→∞simultaneously. 相似文献
992.
993.
Jaechil Yoo 《Journal of Mathematical Analysis and Applications》2003,286(1):326-339
In SIAM J. Numer. Anal. 28 (1991) 1680-1697, Franca and Stenberg developed several Galerkin least squares methods for the solution of the problem of linear elasticity. That work concerned itself only with the error estimates of the method. It did not address the related problem of finding effective methods for the solution of the associated linear systems. In this work, we prove the convergence of a multigrid method. This multigrid is robust in that the convergence is uniform as the parameter ν goes to 1/2. Computational experiments are included. 相似文献
994.
The asymptotic normality for least absolute deviation estimates of the parameters in a linear regression model with autoregressive moving average errors is established under very general conditions. The method of proof is based on a functional limit theorem for the LAD objective function. 相似文献
995.
本文讨论了和四阶梁方程的两参数特征值问题u(4)-αu十=0,u(O)=u(1)=u″(1)=u(1)=0相对应的非线性双参共振梁方程边值问题u(4)-α1u十βu十g(x,u,u″)=h(x),u(0)=u(1)=u″(0)=u(1)=0其中(α1,β1)为特征值对)的解的存在性.应用Lyapunav-Schmidt过程和Leray-Schauder连续定理,得到了该问题的一个存在性结果.推广了Gupta在文[3]中的工作. 相似文献
996.
非齐次对称特征值问题 总被引:5,自引:0,他引:5
引言 用SR~(n×n)表示所有。n×n实对称矩阵的集合。R~n表示n维线性空间。||·||_2表示向量的Euclid范数或矩阵的谱范数。 本文研究如下问题: 问题ISEP 给定矩阵A∈SR~n×n和向量b∈R~n,求实数λ和向量X∈R~n使得 AX=λX+b, (1) ||X||_2=1. (2) 若b=0,则问题ISEP就是通常的实对称矩阵特征值问题,若b≠0,则问题ISEP称为非齐次对称特征值问题,使(1)和(2)式成立的数λ和向量X分别称为非齐次特征值和相应的非齐 相似文献
997.
We investigate new bounding strategies based on different relaxations of the quadratic assignment problem. In particular, we improve the lower bound found by using an eigenvalue decomposition of the quadratic part and by solving a linear program for the linear part. The improvement is accomplished by applying a steepest ascent algorithm to the sum of the two bounds.Both authors would like to thank the Natural Sciences and Engineering Research Council Canada and the Austrian Government for their support.This author would like to acknowledge partial support from the Department of Combinatorics and Optimization at the University of Waterloo.Research partially supported by Natural Sciences and Engineering Research Council Canada. 相似文献
998.
郝江浩 《数学的实践与认识》2004,34(3):154-158
主要应用 Hopf极值原理 ,对一类非线性四阶椭圆型方程Δ2 u +h( x,u,Δu) =0进行研究 ,得到解的泛函的极值原理 .类似的文章结果也有许多 ,其方法均为构造适当的“P-泛函”,但是以前的结果都对方程有较强的要求限制 .本文通过构造新的泛函 ,减弱了要求限制 .同时对方程Δ2 u +λh( x,u,Δu) =0的特征值给出了估计 . 相似文献
999.
安军 《武汉大学学报(理学版)》1996,(3)
对两个相依方程组成的回归系统,当设计矩阵呈病态时,提出了回归系数的一个主成分估计β_1**(k)及其相应的两步估计β_1**(k,T),并在均方误差意义下研究了它们的优良性质。 相似文献
1000.
In [6], an adaptive method to approximate unorganized clouds of points by smooth surfaces based on wavelets has been described. The general fitting algorithm operates on a coarse-to-fine basis. It selects on each refinement level in a first step a reduced number of wavelets which are appropriate to represent the features of the data set. In a second step, the fitting surface is constructed as the linear combination of the wavelets which minimizes the distance to the data in a least squares sense. This is followed by a thresholding procedure on the wavelet coefficients to discard those which are too small to contribute much to the surface representation.
In this paper, we firstly generalize this strategy to a classically regularized least squares functional by adding a Sobolev norm, taking advantage of the capability of wavelets to characterize Sobolev spaces of even fractional order. After recalling the usual cross-validation technique to determine the involved smoothing parameters, some examples of fitting severely irregularly distributed data, synthetically produced and of geophysical origin, are presented. In order to reduce computational costs, we then introduce a multilevel generalized cross-validation technique which goes beyond the Sobolev formulation and exploits the hierarchical setting based on wavelets. We illustrate the performance of the new strategy on some geophysical data.
AMS subject classification 65T60, 62G09, 93E14, 93E24We gratefully acknowledge the support by the Deutsche Forschungsgemeinschaft (KU 1028/7 1 and SFB 611) and by the Basque Government. 相似文献