A method is developed for solving the two dimensional Helmholtz equation in a duct with varying cross-section region bounded by a curved top and flat bottom, having one region inside. To compute the propagation of sound waves in a curved duct with a curved internal interface is difficult problem. One method is to transform the wave equation into a solvable form and making the curved interface p...

It is shown that each subset of positive integers that contains 2 is realizable as the set of essential values of the multiplicity function for the Koopman operator of some weakly mixing transformation.

Using the principle of subordination, we obtain some inclusion properties of certain subclasses of analytic functions defined by a generalized multiplier transformation. Also inclusion properties of these classes involving the generalized integral operator are obtained. Mathematical Subject Classification: 30C45

For anisotropic attenuating media, the albedo operator determines the scattering and the attenuating coefficients up to a gauge transformation. We show that such a determination is stable. Stability of the Gauge Equivalent Classes 2

A technique for automated terrain corrected SAR geocoding is presented. Instead of operator selected control points the presented method uses cross-correlation with a SAR intensity image simulated from the Digital Elevation Model to refine the geocoding transformation.

We show how Ramond free neutral Fermi fields lead to a τ -function theory of BKP type which describes iso-orthogonal deformations of systems of ortogonal curvilinear coordinates. We also provide a vertex operator representation for the classical Ribaucour transformation.

In this paper after defining the abstract concept of compatibilitylike functions on quantum states, we prove that every bijective transformation on the set of all states which preserves such a function is implemented by an either unitary or antiunitary operator.

Using the principle of subordination, we obtain some inclusion properties of subclasses of p-valent functions defined by multiplier transformation. Also inclusion properties of classes involving the generalized Libera integral operator are obtained. 2000 Mathematics Subject Classification: 30C45.

Most approaches used in EAs for problems in which the environment changes from time to time, try to preserve the diversity of the population. One of those approaches applies a new biologically inspired genetic operator called transformation (Simões & Costa, 2001). We tested two EAs using transformation (TGA and ETGA) and two other classical approaches: random immigrants (RIGA) and hypermutation...

An alternative derivation of the Pegg-Barnett phase operator is presented. This approach is based on the properties of the representation in quantum mechanics of a nonlinear nonbijective canonical transformation. It does not use as its starting point either a finite-dimensional space or the definition of phase states. The features of this formalism are analyzed in terms of this transformation. ...