Regularization approaches for the limited-angle reconstruction problem in digital breast tomosynthesis are widelyused. Though, their benefits depend largely upon a suitable regularization parameter estimation. We aim to evaluate the reconstruction quality of precise small contrast features objectively with the help of an automated process. These features were represented by so-called Landolt ri...

Considering non-negative characteristic of the particle size distribution (PSD), based on trust-regionreflective Newton method, two non-negative regularization methods of truncated singular value decomposition (TSVD) and Tikhonov (TIK) for photon correlation spectroscopy (PCS) are proposed in this paper. Combining two regularization parameter criterions of GCV and L-curve, two non-negative regu...

This paper considers subset selection in the presence of noise via algorithms that minimize diversity measures. This leads to iterative procedures like regularized FOCUSS in which each iteration involves the solution to a regularized least squares problem. Several di erent methods for choosing the regularization parameter such as the discrepancy principle and the L-curve technique are evaluated...

This paper focuses on comb-type or scattered pilot arrangement in OFDM systems with a frequency guard band under the time-variant channel. If the maximum channel delay is large, there is a nearly singular matrix problem when a receiver adopts the Frequency Domain LS (FDLS) method to estimate the data subcarrier channel frequency response. This problem renders FDLS channel estimation more sensit...

Abstract. The equations of motion of two point masses in harmonic coordinates are derived through the third post-Newtonian (3PN) approximation. The problem of self-field regularization (necessary for removing the divergent self-field of point particles) is dealt with in two separate steps. In a first step the extended Hadamard regularization is applied, resulting in equations of motion which ar...

For solving linear ill-posed problems regularization methods are required when the right hand side and the operator are with some noise. In the present paper regularized solutions are obtained by Tikhonov regularization in Hilbert scales and the regularization parameter is chosen by the generalized discrepancy principle. Under certain smoothness assumptions we provide order optimal error bounds...

*Correspondence: [email protected] School of Science, Lanzhou University of Technology, Lanzhou, Gansu 730050, P.R. China Abstract This paper is devoted to identifying an unknown source for a time-fractional diffusion equation with variable coefficients in a general bounded domain. This is an ill-posed problem. Firstly, we obtain a regularization solution by the Landweber iterative regularizatio...

In the study of the choice of the regularization parameter for Tikhonov regularization of nonlinear ill-posed problems, Scherzer, Engl and Kunisch proposed an a posteriori strategy in 1993. To prove the optimality of the strategy, they imposed many very restrictive conditions on the problem under consideration. Their results are difficult to apply to concrete problems since one can not make sur...

In this paper we show that regularization methods form a scale-space where the regularization parameter serves as scale. In analogy to nonlinear diiusion ltering we establish continuity with respect to scale, causality in terms of a maximum{minimum principle, simpliica-tion properties by means of Lyapunov functionals and convergence to a constant steady-state. We identify nonlinear regularizati...