With the advances in computer processing that have yielded an enormous increase in performance, numerical analytical approaches based on electromagnetic theory have recently been applied to mobile radio propagation analysis. One such approach is the ray-tracing method based on geometrical optics and the uniform geometrical theory of diffraction. In this paper, ray-tracing techniques that have b...

This paper describes the open-source Phrase-Based Statistical Machine Translation Decoder Phramer. The paper also presents the UTD (HLTRI) system build for the WMT06 shared task. Our goal was to improve the translation quality by enhancing the translation table and by preprocessing the source language text

Finding trends in database data is hard when presented with data sets containing many attributes (columns). The difficulty is increased when the data is in text fields and may include large summary or remarks fields. This paper discusses an approach that uses attribute level clustering in order to discover trends or profiles in the data. This is different from traditional uses of clustering in ...

A propagation model for 3G/4G communication systems is considered in this paper. The analysis method is based on high frequency ray-tracing and the uniform theory of diffraction. The ray contributions includes diffraction from building edges, reflection from the ground and building and the direct wave. According to the elevation angle of the impinging signal, different propagation components wi...

In this paper, we present new results on using orthogonal matching pursuit (OMP), to solve the sparse approximation problem over redundant dictionaries for complex cases (i.e., complex measurement vector, complex dictionary and complex additive white Gaussian noise (CAWGN)). A sufficient condition that OMP can recover the optimal representation of an exactly sparse signal in the complex cases i...

Knowing the solution to Helmholtz equation in a narrow band, with a width of order wave length around a scatterer, we investigate the possibility to construct the wave fronts predicted by the asymptotic methods Geometrical Optics (GO) and Geometrical Theory of Diffraction (GTD). More specifically we show how to build a polynomial approximation of the asymptotic solution on a circle around the s...

Propagation characteristics play a fundamental role in the design and implementation of radio systems. The application of broadband digital data services within the cordless environment requires close consideration of the dispersive nature of radio channels. A prediction algorithm is presented such that propagation characteristics can be estimated for small cell high data rate systems. Through ...

We present an algorithm for fast computation of diffraction paths for geometric-acoustics in complex environments based on the UTD formulation. Our method extends ray-frustum tracing to efficiently compute paths in the shadow region caused by long diffracting edges. Our approach can handle general scenes with moving sources, receivers, and dynamic objects. We evaluate the accuracy through compa...

In this paper comparison of Reflector Antenna analyzing techniques based on wave and ray nature of optics is presented for an offset reflector antenna using GRASP (General Reflector antenna Analysis Software Package) software. The results obtained using PO (Physical Optics), PTD (Physical theory of Diffraction), and GTD (Geometrical Theory of Diffraction) are compared. The validity of PO and GT...

This paper presents a simple model for the evaluation of obstruction caused by multiple buildings in satellite mobile communication systems, or in high-altitude platform (HAP) coverage. The proposed model can be useful for integration into propagation prediction tools. It is based on the KichhoffHuygens formulation, and includes the effect of ground reflections and reflections on a facing build...