A sequence of least squares problems of the form miny kG1=2(AT y h)k2, where G is an n n positive definite diagonal weight matrix, and A anm n (m n) sparse matrix with some dense columns; has many applications in linear programming, electrical networks, elliptic boundary value problems, and structural analysis. We suggest low-rank correction preconditioners for such problems, and a mixed solver...

The paper evaluates two different bias correction schemes for Vaisala RS92 measurements. Given that RS92 sensors are used globally to measure tropospheric humidity, the comparison is valuable. Because of my interest in the topic, I am providing a few comments that may help to improve the paper. However, please note that the comments here should not be considered as editor’s decision but solely ...

In this article, we discuss a least-squares/fictitious domain method for the solution of linear elliptic boundary value problems with Robin boundary conditions. Let Ω and ω be two bounded domains of Rd such that ω⊂Ω. For a linear elliptic problem in Ω\ω with Robin boundary condition on the boundary γ of ω, our goal here is to develop a fictitious domain method where one solves a variant of the ...

Abstract. Existing analysis shows that when the Gauss Runge-Kutta (GRK) (also called Legendre-Gauss collocation) formulation with s Gaussian nodes is applied to ordinary differential equation initial value problems, the discretization has order 2s (super-convergent) [8]. However, for time-dependent partial differential equations (PDEs) with boundary conditions, super-convergence is only observe...

We re-examine the justification for the imposition of regular boundary conditions on the wavefunction at the Coulomb singularity in the treatment of the hydrogen atom in non-relativistic quantum mechanics. We show that the issue of the correct boundary conditions is not independent of the physical structure of the proton. Under the physically reasonable assumption that the finite size and struc...

Basic experiments were conducted on a large-size broad-crested weir with a rounded corner. Detailed free-surface, velocity, and pressure measurements were performed for a range of flow conditions. The results showed the rapid flow distribution at the upstream end of the weir and next to the weir brink at large flow rates. The flow properties above the crest were analyzed taking into account the...

A time-domain boundary condition is derived that accounts for the acoustic impedance of a thin boundary layer over an impedance boundary, based on the asymptotic frequency-domain boundary condition of Brambley [2011, AIAA J. 49(6), pp. 1272–1282]. A finite-difference reference implementation of this condition is presented and carefully validated against both an analytic solution and a discrete ...

In this study, we made some heuristic rules related to the boundary of protein names for automated extraction of protein names from biomedical literatures. The automated extraction of protein names was carried out based on Support Vector Machine (SVM). ¿From the analysis of the results, we found whether some words of modifier words set were included or not as part of protein names. It is critic...

We present a numerical algorithm to solve the low-Mach number approximation of the conservation laws for laminar flames. Elements of our algorithm are a pressure correction (PC) method to decouple the computation of velocity and pressure, and a multi-level local defect correction (LDC) method to solve the resulting set of (non)linear boundary value problems. The PC method is based on a constrai...

objective(s): in spect, the sinogram contains scatter and lack of attenuated counts that degrade the reconstructed image quality and quantity. many techniques for attenuation and scatter correction have been proposed. an acceptable method of correction is to incorporate effects into an iterative statistical reconstruction. here, we propose new maximum likelihood expectation maximization (mlem) ...