275 citations · 1.7k across the 132 of their papers we have counts for
10 papers · 1 filter
Determination of the Spacetime from Local Time Measurements
Matti Lassas, Lauri Oksanen, Yang Yang
We consider an inverse problem for a Lorentzian spacetime , and show that time measurements, that is, the knowledge of the Lorentzian time separation function on a submanifo…
Superdimensional Metamaterial Resonators
Allan Greenleaf, Henrik Kettunen, Yaroslav Kurylev +2
We propose a fundamentally new method for the design of metamaterial arrays, valid for any waves modeled by the Helmholtz equation, including scalar optics and acoustics. The desig…
Inverse acoustic scattering problem in half-space with anisotropic random impedance
Tapio Helin, Matti Lassas, Lassi Päivärinta
We study an inverse acoustic scattering problem in half-space with a probabilistic impedance boundary value condition. The Robin coefficient (surface impedance) is assumed to be a…
Multi-resolution parameter choice method for total variation regularized tomography
Kati Niinimäki, Matti Lassas, Keijo Hämäläinen +4
A computational method is introduced for choosing the regularization parameter for total variation (TV) regularization. The approach is based on computing reconstructions at a few…
On Absence and Existence of the Anomalous Localized Resonance without the Quasi-static Approximation
Henrik Kettunen, Matti Lassas, Petri Ola
The paper considers the transmission problems for Helmholtz equation with bodies that have negative material parameters. Such material parameters are used to model metals on optica…
Inverse problem for Einstein-scalar field equations
Yaroslav Kurylev, Matti Lassas, Lauri Oksanen +1
The paper introduces a method to solve inverse problems for hyperbolic systems where the leading order terms are non-linear. We apply the method to the coupled Einstein-scalar fiel…