6 citations · 7 across the 3 of their papers we have counts for
5 papers
Generalized Pellet's theorem for analytic matrix-valued functions
Hiromochi Itoh, Kei Matsushima, Takayuki Yamada
Generalized Pellet's theorem is extended to analytic matrix-valued functions using Descartes' rule of signs for infinite series. Cauchy's estimate is incorporated to allow numerica…
Exceptional points and defective resonances in an acoustic scattering system with sound-hard obstacles
Kei Matsushima, Takayuki Yamada
This paper is concerned with non-Hermitian degeneracy and exceptional points associated with resonances in an acoustic scattering problem with sound-hard obstacles. The aim is to f…
Topology optimization of isotropic viscoelastic microstructures based on periodic homogenization
Hiroaki Deguchi, Kei Matsushima, Takayuki Yamada
Mitigating low-frequency noise is particularly challenging due to its limited natural attenuation. This study aims to design viscoelastic composite microstructures that achieve bot…
Observation of exceptional points in a spherical open elastic system
Hiroaki Deguchi, Kei Matsushima, Takayuki Yamada
Exceptional points (EPs) are spectral singularities in non-Hermitian systems where eigenvalues and their corresponding eigenstates coalesce simultaneously. In this study, we calcul…
Non-Bloch band theory for time-modulated discrete mechanical systems
Kei Matsushima, Takayuki Yamada
This study establishes a non-Bloch band theory for time-modulated discrete mechanical systems. We consider simple mass-spring chains whose stiffness is periodically modulated in ti…