We present an extremely fast method named FAST-PVE for tissue classification and partial volume estimation of 3-D brain magnetic resonance images (MRI) using a Markov Random Field (MRF) based spatial prior. The tissue classification problem is central to most brain MRI analysis pipelines and therefore solving it accurately and fast is important. The FAST-PVE method is experimentally confirmed t...

An approach to image localized and propagating surface plasmon ~SP! modes is introduced. It is shown that scanning tunneling microscope ~STM!-electroluminescence, the radiative decay of SPs induced by inelastically tunneling electrons, observed in Fourier space yields distinct features that reflect the degree of delocalization and spatial distribution of SP modes. The propagating SP is isolated...

We study the small-scale topology of dynamical phenomena in the quiet-sun internetwork atmosphere, using short-duration Fourier analysis of high-resolution filtergram sequences to obtain statistical estimates for the co-location probability of different fine-structure elements and wave modes. In this initial paper we concentrate on the topology of shortduration Fourier amplitude maps for the ph...

We study synchronization in a system of phase-only oscillators residing on the sites of a one-dimensional periodic lattice. The oscillators interact with a strength that decays as a power law of the separation along the lattice length and is normalized by a size-dependent constant. The exponent α of the power law is taken in the range 0≤α<1. The oscillator frequency distribution is symmetric ab...

A modulated Fourier expansion in time is used to show long-time nearconservation of the harmonic actions associated with spatial Fourier modes along the solutions of nonlinear wave equations with small initial data. The result implies the long-time near-preservation of the Sobolev-type norm that specifies the smallness condition on the initial data.

We investigated drift-wave turbulence in the plasma edge of a small tokamak by considering solutions of the Hasegawa-Mima equation involving three interacting modes in Fourier space. The resulting low-dimensional dynamics presented periodic as well as chaotic evolution of the Fourier-mode amplitudes, and we performed the control of chaotic behaviour through the application of a fourth resonant ...

In the standard picture of cosmological structure formation, initially random-phase fluctuations are amplified by non-linear gravitational instability to produce a final distribution of mass which is highly non-Gaussian and has highly-coupled Fourier phases. We use the Zel’dovich approximation in one dimension to elucidate the onset of non-linearity including mode spawning, merging and coupling...

A two-dimensional and dissipative Rayleigh–Bénard convection can be approximated by the Lorenz model, which was originally derived by taking into account only three Fourier modes. Numerous attempts have been made to generalize this 3D model to higher dimensions and several different methods of selecting Fourier modes have been proposed. In this paper, generalized Lorenz models with dimensions r...

Spatial Fourier transforms of quasipatterns observed in Faraday wave experiments suggest that the patterns are well represented by the sum of 8, 10 or 12 Fourier modes with wavevectors equally spaced around a circle. This representation has been used many times as the starting point for standard perturbative methods of computing the weakly nonlinear dependence of the pattern amplitude on parame...