2002 International Telecommunications Symposium

"In this article, new results are presented of the application of the modified successive elimination (SE) algorithm [1] in the estimation of motion vectors as used in video compression. The modified SE algorithm represents an evolution of the SE algorithm proposed by Li and Salari [2]. SE algorithm works by pre-selecting blocks in the research area...

"In this article, a simple and robust algorithm for image compression is proposed. The algorithm is a modified version of Creusere's Robust Embedded Zerotree Wavelet (REZW) algorithm [1], where arithmetic coding is replace by Huffman coding. It is intended for use in noisy channels such as those found in wireless communications."

"The technological development of Global Positioning Systems (GPS) and the increase of its potential applications lead to the need of a channel simulation tool, in order to study different kinds of interference and attenuation in the GPS signal. The contribution of this work consists in the development of a software package that enables the analysis of...

"Importance sampling (IS) is a modified Monte Carlo (MC) simulation technique that improves computational efficiency by reducing the variance of a given simulation estimator. In this paper IS is combined with error event simulation in order to evaluate efficiently the performance of Viterbi decoding used on a nonsymmetric and on an erasure binary-input...

"The major purpose of this contribution is to analyze an hierarchical cell structure with a hot spot embedded in a WCDMA macrocellular system. Particular attention is paid to the impact of the introduction of smart antennas in this context. A system-level simulation approach is employed where we consider two main solutions to deal with the hot spot...

"The stochastic properties of the binary channel that describe the successes and the failures of the transmission of a modulated signal over a time correlated flat fading channel is considered for investigation. This analysis is employed to develop K-th order Markov models for such a burst channel. The order of the Markov model that generates accurate...

"Network traffic presents long range dependences and is usually modeled either by fractal or by multifractal processes. The Hurst parameter is a measure of the self-similarity of a process. In this paper, a neuro estimator of the Hurst parameter is proposed and compared to statistical estimators"

"We consider the discrete-time gated multiple-vacation queue. Vacations are modeled as independent random variables with distributions depending on the number of the immediately preceding vacations. Using a probability generating function approach, we focus on various performance measures such as moments of queue contents and customer delay in...

"This paper presents a mechanism for the dynamic sizing of Label Switched Paths (LSPs) in MPLS networks based on an investigation of the mean queue size at the ingress router of the LSP. Upon exceeding established thresholds, the mechanism is triggered and the LSP is resized after a signaling delay. Through simulations using a self-similar traffic...

"In this paper a genetic algorithm is used in the design of a linear antenna array, aiding the designer to find the best antenna for his application. The designer indicates the number of elements of the set, the direction of the main lobe, the side lobe level, and the half-power beamwidth. In this methodology the objective function takes into account the...