This paper describes how the phase, obtained by Gabor filtering an image, can be used to aggregate related Gabor elements (simple features identified by peaks in the Gabor magnitude). This phase-based feature grouping simplifies the perennial problem of target/background segmentation because we need to only determine if the aggregate feature is target or background, rather than determine the st...

In this paper we present a technique for shape similarity estimation and apply it to content-based indexing and retrieval over large image databases. This technique is based on wavelet decomposition and uses polygonal approximation. It uses simple features (aspect ratio, angles, distances from the centroid, distance ratios and relative positions) extracted at high curvature points. The experime...

Numerical simulations of crack initiation which use a cohesive zone law to model a weak interface in the solid are often limited by the occurrence of an elastic snap-back instability. At the point of instability, quasi-static finite element computations are unable to converge to an equilibrium solution, which usually terminates the calculation and makes it impossible to follow the postinstabili...

The Rayleigh–Taylor ~RT! instability is important in a number of research contexts. For the design or analysis of experiments and observations, it is often useful to know the growth exponent of an interface, even when the growth is strongly nonlinear. The growth exponent is defined here as the number of linear e-foldings by which initial perturbations at the interface would be amplified, if the...

We present and analyse two new Volume-of-Fluid (VOF) reconstruction algorithms that approximate the interface separating two immiscible fluids as a linear function in each grid cell (PLIC Piecewise Linear Interface Calculation). The first one is based on two simple geometrical criteria for the reconstruction of a linear interface, the second one minimizes a distance functional to find the plane...

The level splitting formulae much discussed in the study of spin tunneling in macroscopic ferromagnetic particles and previously derived only by complicated pseudoparticle methods for the ground state, are derived from those of eigenvalues of periodic equations and extended to excited states. PACS numbers:11.15KC, 73.40GK, 75.60JP, 03.65Db

the direct torque control (dtc) of interior permanent magnet synchronous motor (ipmsm) offers simple structure and fast torque response. the conventional switching table-based dtc (st-dtc) presents some disadvantages like high torque and flux ripple and also variable switching frequency. this paper investigates the improved st-dtc strategies to reduce both torque and flux ripple in dtc of ipmsm...