نتایج جستجو برای: tikhonov regularization method

تعداد نتایج: 1642536  

2008
Stéphane Crépey

An important issue in quantitative nance is model calibration. The calibration problem is the inverse of the pricing problem. Instead of computing prices in a model with given values for its parameters, one wishes to compute the values of the model parameters that are consistent with observed prices. Now, it is well-known by physicists that such inverse problems are typically ill-posed. So, if ...

Journal: :Int. J. Comput. Math. 2007
Hisham Bin Zubair C. C. W. Leentvaar Cornelis W. Oosterlee

Several numerical methods for the solution of large linear ill-posed problems combine Tikhonov regularization with an iterative method based on partial Lanczos bidiagonalization of the operator. This paper discusses the determination of the regularization parameter and the dimension of the Krylov subspace for this kind of methods. A method that requires a Krylov subspace of minimal dimension is...

Journal: :Methods and Applications of Analysis 2011

Journal: :Journal of Computational and Applied Mathematics 2009

2015
Youssef Mroueh Etienne Marcheret Vaibhava Goel

Joint modeling of language and vision has been drawing increasing interest. A multimodal data representation allowing for bidirectional retrieval of images by sentences and vice versa is a key aspect of this modeling. In this paper we show that a cross-view mapping of the search space to the query space achieves state of the art performance in bidirectional retrieval using off the shelf feature...

2013
Ashraf Y. A. Maghari Ibrahim Venkat Iman Yi Liao Bahari Belaton

Reconstructing a 3D face shape from a limited number of 2D facial feature points is considered as an ill-posed problem which can be solved using regularization. Tikhonov regularization is a popular method that incorporates prior information towards providing the existence of closed-form solutions which we obtain as a result of applying PCA, in order to solve the ill-posed problem. The common fa...

Journal: :Journal of biomedical optics 2012
Ravi Prasad K Jagannath Phaneendra K Yalavarthy

The inverse problem in the diffuse optical tomography is known to be nonlinear, ill-posed, and sometimes under-determined, requiring regularization to obtain meaningful results, with Tikhonov-type regularization being the most popular one. The choice of this regularization parameter dictates the reconstructed optical image quality and is typically chosen empirically or based on prior experience...

2014
Serena Morigi Lothar Reichel Fiorella Sgallari

This paper introduces a new approach to computing an approximate solution of Tikhonov-regularized large-scale ill-posed problems with a general nonlinear regularization operator. The iterative method applies a sequence of projections onto generalized Krylov subspaces using a semi-implicit approach to deal with the nonlinearity in the regularization term. A suitable value of the regularization p...

2008
Jodi L. Mead Rosemary A. Renaut

We discuss the solution of numerically ill-posed overdetermined systems of equations using Tikhonov a-priori-based regularization. When the noise distribution on the measured data is available to appropriately weight the fidelity term, and the regularization is assumed to be weighted by inverse covariance information on the model parameters, the underlying cost functional becomes a random varia...

2012
Kyunghyun Cho Alexander Ilin Tapani Raiko

In this paper, we study a Tikhonov-type regularization for restricted Boltzmann machines (RBM). We present two alternative formulations of the Tikhonov-type regularization which encourage an RBM to learn a smoother probability distribution. Both formulations turn out to be combinations of the widely used weight-decay and sparsity regularization. We empirically evaluate the effect of the propose...

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