We construct a numerical scheme based on the Liouville equation of geometric optics coupled with the Geometric Theory of Diffraction (GTD) to simulate the high frequency linear waves diffracted by a half plane. We first introduce a condition, based on the GTD theory, at the vertex of the half plane to account for the diffractions, and then build in this condition as well as the reflection bound...

The increase in mobile communications traffic has led to heightened interest in the use of deterministic propagation methods together with digital building and terrain databases for propagation prediction in urban areas. Ray methods have been particularly popular, and there are many papers in the literature describing the performance of various approaches to ray tracing. This paper will describ...

Unsupervised term discovery (UTD) is the task of automatically identifying the repeated words and phrases in a collection of speech audio without relying on any language-specific resources. While the solution space for the task is far from fully explored, the dominant approach to date decomposes the discovery problem into two steps, where (i) segmental dynamic time warping is used to search the...

. We measure and compare the effects of changing the programming language in introductory level courses (Computer Science I and II) in undergraduate Computer Science (CS) curriculum. The study presents the example of University of Texas at Dallas (UTD) case, where we present the results of two approaches: Approach 1 where both CS I and CS II courses are taught in Java, and Aprroach 2 where CS I...

nanocrystalline particles of cerium oxide (ceo2) have been prepared by the chemical precipitation method using cerium nitrate and urea with a molar ratio of 1:2. the results revealed that the formation of ceo2 fine particles is influenced by molar ratio of metal nitrates to fuel. well faceted ceo2 nanoparticles, were synthesized by thermal-assisted dissociation method at reflux temperature in a...

A detailed model of diffraction of Gaussian beams on plane uniform volume Bragg gratings based on a Kogelnik’s theory of coupled waves is presented. The model describes transmitting and reflecting gratings and takes into account spectral width and angular divergence of diffracted beams. Exact formulas for angular and spectral selectivity are derived. Conditions for Bragg diffraction based on co...

Two compact analytical descriptions of Fresnel diffraction patterns from polygonal apertures under uniform illumination are detailed. In particular, a simple expression for the diffracted field from constituent edges is derived. These results have fundamental importance as well as specific applications, and they promise new physical insights into diffraction-related phenomena. The usefulness of...

This paper presented a theoretical and numerical investigation of the Compact Antenna Test Range (CATR) equipped with Super Hybrid Modulated Segmented Exponential Serrations (SHMSES). The investigation was based on diffraction theory and, more specifically, the Fresnel diffraction formulation. The CATR provides uniform illumination within the Fresnel region to test antenna. Application of serra...