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NIMS-National Institute for Mathematical Sciences South Korea

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Papers

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765

Fast identification of short, sound-soft open arcs by the orthogonality sampling method in the limited-aperture inverse scattering problem

의료수학연구부 | Chi Young Ahn; Seongje Chae; Won-Kwang Park* | Applied Mathematics Letters 109 (2020)

The orthogonality sampling method (OSM) is a recently developed non-iterative technique for imaging and identifying targets in inverse scattering problems. In this paper, a set of short sound-soft open arcs is obtained by OSM in the limited-aperture inverse scattering problem.

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764

A multi-stage SIR model for rumor spreading

의료수학연구부 | Sun-Ho Choi; Hyowon Seo*, MINHA YOO | DISCRETE AND CONTINUOUS DYNAMICAL SYSTEMS-SERIES B 25(6) (2020)

We propose a multi-stage structured rumor spreading model that consists of ignorant, new spreader, old spreader, and stifler. We derive a mean field equation to obtain the multi-stage structured model on homogeneous networks. 

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763

Low-dose CT Image Reconstruction with a Deep Learning Prior

의료수학연구부 | HYOUNG SUK PARK; KIWAN Jeon*; KYUNGSANG KIM | IEEE Access 18(1) (2020)

In low-dose computed tomography (LDCT), a penalized weighted least squares (PWLS) approach that incorporates the Poisson statistics of X-ray photons can significantly reduce excessive quantum noise.

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762

Single- and Multi-Frequency Direct Sampling Methods in a Limited-Aperture Inverse Scattering Problem

의료수학연구부 | SANGWOO KANG; MARC LAMBERT; CHI YOUNG AHN; TAEYOUNG HA; and WON-KWANG PARK | IEEE Access 8 (2020)

Although the direct sampling method (DSM) has demonstrated its feasibility and robustness for imaging of small inhomogeneities, mathematical analyses of DSM have been conducted only on the full-aperture inverse scattering problem.

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761

Localization of Small Anomalies via the Orthogonality Sampling Method from Scattering Parameters

의료수학연구부 | Seongje Chae; Chi Yong Ahn; Won-Kwang Park* | Electronics 9(1119) (2020)

We investigate the application of the orthogonality sampling method (OSM) in microwave imaging for a fast localization of small anomalies from measured scattering parameters.

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760

A joint Fermi-GBM and LIGO/Virgo analysis of compact binary mergers from the first and second gravitational-wave observing runs

산업수학기반연구부 | R. Hamburg et al.(W. S. Kim; J. J. Oh; S. H. Oh; E. J. Son) | The Astrophysical Journal 893(100) (2020)

We present results from offline searches of Fermi Gamma-ray Burst Monitor (GBM) data for gamma-ray transients coincident with the compact binary coalescences observed by the gravitational-wave (GW) detectors Advanced LIGO and Advanced Virgo during their first and second observing runs.

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759

Fast and slow velocity alignments in a Cucker-Smale ensemble with adaptive couplings

의료수학연구부 | Seung-Yeal Ha; Dohyun Kim, Jinyeong Park | Communications on Pure and Applied Analysis 19(9) (2020)

We study the emergent dynamics of the Cucker-Smale (C-S for brevity) ensemble under adaptive couplings. For the adaptive couplings, we basically consider two types of couplings: Hebbian vs. anti-Hebbian. When the Hebbian rule is employed, we present sufficient conditions leading to the mono-cluster flocking using the Lyapunov functional approach. On the other hand, for the anti-Hebbian rule, the possibility of mono-cluster flocking mainly depends on the integrability of the communication weight function and the regularity of the adaptive law at the origin. In addition, we perform numerical experiments and compare them with our analytic results.

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758

Emergence of Bicluster Aggregation for the Swarm Sphere Model with Attractive-Repulsive Couplings

의료수학연구부 | Seung-Yeal Ha; Dohyun Kim; Jaeseung Lee; Se Eun Noh | SIAM Journal on Applied Dynamical Systems 19(2) (2020)

We study emergent behaviors of the swarm sphere model under attractive-repulsive couplings and present several sufficient frameworks leading to the complete and practical bicluster aggregations using two key ingredients (two-point correlation function and order parameter).

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757

State-Dependent Dynamics of the Lohe Matrix Ensemble on the Unitary Group under the Gradient Flow

의료수학연구부 | Dohyun Kim | SIAM Journal on Applied Dynamical Systems 19(2) (2020)

We study the emergent behavior of the matrix ensemble on the unitary group in which a state of each oscillator is influenced by the relative distances. Thus, the coupling strength becomes a time-dependent function and its temporal evolution is determined by a feedback rule incorporating the linear damping and the function of the relative distances between oscillators.

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756

Emergent behaviors of a first-order particle swarm model on the hyperboloid

의료수학연구부 | Seung-Yeal Ha; Seungsu Hwang ; Dohyun Kim*; Sun-Chul Kim and Chanho Min | Journal of Mathematical Physics 61 (2020)

We study the emergent dynamics of a first-order particle swarm model (PSM) on the hyperboloid with a constant negative curvature that corresponds to the special case (p, q) = (1, d) of the PSM on the indefinite special orthogonal group SO(p, q) in the work of Ritchie et al.

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