VII International Telecommunications Symposium

This paper compares the video quality performance of low definition (LD), standard definition (SD) and high definition (HD) video signals encoded with H.264/AVC and Dirac using full-reference (PSNR and SSIM) and no-reference metrics (JPEG-NR) for different bit rates. It is shown that H.264 outperforms Dirac concerning quality for all resolutions.

A new Markovian model (MM) for burst-error generation has been recently presented by the authors. This model is conveniently structured, with the double purpose of reproducing the generation of some typical patterns of burst error sequences and facilitating the maximum-likelihood (ML) estimation of the its parameters. In the present work we...

This work presents a Self-similar QoS Manager using a immunological algorithm to optimize a MPLS network. The system receives a set of requirements, imposed by many different client applications, and creates a set of paths that satisfy all the capacity constraints necessary for each specific traffic. The solution also keeps the load balance in the...

In this article we present a software to simulate Transparent Optical Networks (SIMTON). SIMTON is an eventdriven simulation software implemented in C++ which takes into account optical device characteristics for the evaluation of network blocking probability in wavelength routed transparent optical networks. The simulator uses a physical layer model...

This work analyzed numerically the relationship between DOP, PMD and PDL dispersion effects in high-rate optical communication systems for differential phase-shiftkeying modulation. It was considered 10 Gb/s and 20 Gb/s transmission rates for RZ-DPSK and RZ-DPSK (duty cycle 50% and 33%) signals.

The information security issues in the current communication networks demand the development of efficient methods to find security vulnerabilities and facilitate the decision making process. Security metric is a widely used concept in this area. The metrics can indicate the actual level of a specific security target and may determine the...

This work presents a discussion about multi-frame Super-Resolution Reconstruction (SRR) and single-frame interpolation. SRR has been extensively studied in the last decades but it is not yet as popular as image interpolation. Since both methods are directed to improve image quality, comparisons are inevitable and desirable. However, fundamental...

Currently, there are many wireless networks based on different radio access technologies (RATs). Despite this, new kind of networks will be developed to complement those already existing today. As there will be no RAT able to give users full service requirements with universal coverage, the next generation wireless networks will integrate multiple...

The development of software radio toward the cognitive radio brought the hope that the spectrum scarcity would be finally an issue of the past. Due to the characteristics of the cognitive operation and environment (including spectrum sharing), the operation of such a system has to take into account the interference to and from other wireless...

Text-to-speech (TTS) is currently a mature technology that is used in many applications. Some modules of a TTS depend on the language and, while there are many public resources for English, the resources for some underrepresented languages are still limited. This work describes the development of a complete TTS system for Brazilian Portuguese which...