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The Method of Image Singularities Employed for Oscillating Oblate Spheroids under a Free Surface

Fluids, 2020
The main objective of this study is to develop a semi-analytical formulation for the radiation problem of a fully immersed spheroid in a liquid field of infinite depth.
Eirini I. Anastasiou, Eva Loukogeorgaki, Ioannis K. Chatjigeorgiou   +2 more
doaj   +4 more sources

Image of the thin accretion disk around compact objects in the Einstein–Gauss–Bonnet gravity [PDF]

European Physical Journal C: Particles and Fields, 2021
We study the optical appearance of a thin accretion disk around compact objects within the Einstein–Gauss–Bonnet gravity. Considering static spherically symmetric black holes and naked singularities we search for characteristic signatures which can arise
Galin Gyulchev, Petya Nedkova, Tsvetan Vetsov, Stoytcho Yazadjiev   +3 more
doaj   +2 more sources

Observational signatures of strongly naked singularities: image of the thin accretion disk [PDF]

European Physical Journal C: Particles and Fields, 2020
We study the optical appearance of a thin accretion disk around the strongly naked static Janis–Newman–Winicour singularity. The solution does not possess a photon sphere, which results in the formation of a complex structure of bright rings in the ...
Galin Gyulchev, Jutta Kunz, Petya Nedkova, Tsvetan Vetsov, Stoytcho Yazadjiev   +4 more
doaj   +2 more sources

The Radiation Problem of a Submerged Oblate Spheroid in Finite Water Depth Using the Method of the Image Singularities System

Fluids, 2022
This study examines the hydrodynamic parameters of a unique geometry that could be used effectively for wave energy extraction applications. In particular, we are concerned with the oblate spheroidal geometry that provides the advantage of a wider impact
Eirini I. Anastasiou, Ioannis K. Chatjigeorgiou   +1 more
doaj   +3 more sources

Ultimate Image Singularities in Oblate Spheroidal Coordinates with Applications in Hydrodynamics

Journal of Marine Science and Engineering, 2020
This study exploits the Touvia Miloh oblate spheroid theorem with a special focus on hydrodynamical applications. The theorem provides explicit relations that express the oblate spheroidal harmonics, given in terms of the fundamental solutions of the ...
Ioannis K. Chatjigeorgiou, Eva Loukogeorgaki, Eirini Anastasiou, Nikos Mantadakis   +3 more
doaj   +3 more sources

Phase singularities for image representation and matching [PDF]

Proceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processing, 2008
Phase features are widely used in image processing and representation due to their stability to deformation and noise. However, phase singularities,where the signals vanish, are generally regarded as harmful and unreliable facts. In this paper, on the contrary, we will show that phase singularities calculated by Laguerre-Gauss filter contain important ...
Jianzhuang Liu, Nobuaki Minematsu, Xiaoou Tang   +2 more
exaly   +2 more sources

Image based visual servoing with kinematic singularity avoidance for mobile manipulator [PDF]

PeerJ Computer Science
This article presents an implementation of visual servoing (VS) for a redundant mobile manipulator in an eye-in-hand configuration. We used the image based visual servoing (IBVS) scheme, which means the pose control of the robot is based on the error ...
Jesus Hernandez-Barragan, Carlos Villaseñor, Carlos Lopez-Franco, Nancy Arana-Daniel, Javier Gomez-Avila   +4 more
doaj   +3 more sources

Polarization singularities of biological tissues images.

Journal of Biomedical Optics, 2006
The ways to the polarization singularities of the biological tissues images of various morphological structures have been theoretically analyzed. The coordinate distributions of singly (linear states of polarization) and doubly degenerated (circular states of polarization) polarization singularities of the physiologically normal and pathologically ...
O. Angelsky, A. Ushenko, Y. Ushenko, Y. Tomka   +3 more
semanticscholar   +3 more sources

A novel MRI PET image fusion using shearlet transform and pulse coded neural network [PDF]

Scientific Reports
Image fusion involves combining details from two or more different imaging techniques, say MRI and PET images and provides a better image for diagnosis and treatment. Despite the fact standard spatial domain methods are being used successfully, including
Vella Satyanarayana, P. Mohanaiah
doaj   +2 more sources

Spacetime perspective of gravitational lensing in perturbed cosmologies [PDF]

Scientific Reports
We develop the spacetime approach to gravitational lensing by spherically symmetric perturbations of flat, cosmological constant-dominated Friedman-Robertson-Walker metrics.
Thomas P. Kling, Sophia MacQueen Pooler
doaj   +2 more sources