The 19th : Seminar on Mathematics for various disciplines

Place :: Graduate School of Mathematical Sciences the University of Tokyo, Room #056＆ Room #052

Programme :

Kazufumi Ito (North Carolina State University, USA): Adaptive Tikhonov Regularization for Inverse Problems

ABSTRACT:: Tikhonov regularization method plays a critical role in ill-posed inverse problems, arising in applications including computerized tomography, inverse scattering and image processing. The goodness of the inverse solution heavily depends on selection of the regularization parameter. Commonly used methods rely on a priori knowledge of the noise level. A method that automatically estimates the noise level and selects the regularization parameter automatically is presented.

Yimin Wei (Fudan University, P.R. of China): On mixed and componentwise condition numbers for Moore-Penrose inverse and linear least squares problems

ABSTRACT:: Classical condition numbers are normwise: they measure the size of both input perturbations and output errors using some norms. To take into account the relative of each data component, and a possible data sparseness, componentwise condition numbers have been increasingly considered. These are mostly of two kinds: mixed and componentwise. In this talk, we give explicit expressions, computable from the data, for the mixed and componentwise condition numbers for the computation of the Moore-Penrose inverse as well as for the computation of solutions and residues of linear least squares problems. In both cases the data matrices have full column (row) rank.

19th Seminar on Mathematics for various disciplines