VII International Telecommunications Symposium

The work on real forensics videos involving banking images lead to the method presented here: a software approach to the problem of demultiplexing time multiplexed security videos. This approach is of particular interest in cases in which, for some reason, the regular demultiplexing hardware/software is not available. Based on comparisons of the...

The proceedings of many technical events in different areas of knowledge witness the history of the development of that area. This paper describes LiveMemory, a user friendly software platform designed to generate digital libraries of proceedings.

This paper offers a new regard on compactly supported wavelets derived from FIR filters. Although being continuous wavelets, analytical formulation are lacking for such wavelets. Close approximations for daublets (Daubechies wavelets) and their spectra are introduced here. The frequency detection properties of daublets are investigated...

Hybrid Automatic Repeat Query (HARQ) is an error correction technique that has become an integral part of most current broadband wireless standards such as IEEE 802.16 and 3GPP-LTE (Long Term Evolution). Although extensive studies have been made on the performance of HARQ, they usually assume perfect channel state information at the receiver. This...

The next generation of mobile communications will merge the well-known infrastructured wireless networks and the infrastructureless mobile ad hoc networks. However, their natural characteristics make them vulnerable to numerous severe attacks, making security a major issue in such networks. Cryptography mechanisms, both symmetric and asymmetric,...

Very often documents are written on both sides on translucent paper making visible the ink from one side on the other. This artifact was called “back-to-front interference”. The direct binarization of documents with such interference yields unreadable documents. A mirror transformation to remove such noise was suggested over a decade ago, but there...

This paper presents a blocking-effect reduction in a method for reversed-complexity video codec. We used intra predicted frames encoded at different quality (distortion) targets. We propose a technique to improve the enhancement layer of a mixed-quality encoded sequence, using information from the high-quality (key) frames to enhance the...

EGPRS2 is part of the GERAN evolution standardized in 3GPP GERAN Release 7 and it allows higher throughput rates per timeslot due to the adoption of higher order modulation, higher symbol rate, turbo codes and spectrally wide pulse shape. Another possibility for EGPRS2 adoption by operators is to keep the existing EGPRS throughput rates using less...

This paper presents a new fast algorithm for computing an N-point discrete Fourier transform. The algorithm meets the Heideman multiplicative complexity lower bound for N = {3, 4, 6, 8, 12} and is based upon the decomposition of the elements of the transform matrix into a cyclotomic basis.

This paper proposes a new strategy for fitting Hidden Markov Models to error processes of channels with memory. Our approach consists of obtaining the analytical expression of the likelihood function of the model parameters and applying particle swarm optimization (PSO) to obtain their maximum likelihood (ML) estimates. In particular, this approach...