XXXV Simpósio Brasileiro de Telecomunicações e Processamento de Sinais

This work proposes an automatic fault classifier that uses similarity-based modeling (SBM) to identify faults on rotating machines. The similarity model can be used either as an auxiliary model to generate features for a classifier or as a standalone classifier. A new approach for training the model using a prototype-selection method is...

A falta de monitoramento adequado do fluxo de usuários nos sistemas de transporte público metroviários, pode comprometer à segurança e o bem-estar dos passageiros. Nesse artigo, é proposto um modelo estimativo em tempo real, automático e contínuo, do fluxo de passageiros do sistema metroviário da CBTU (Companhia Brasileira de Trens Urbanos) de...

This work presents a study, using the least squares estimation theory, about the existence of bias in the estimate and the slow convergence of the traditional adaptive filtering algorithms when applied in acoustic feedback cancellation. These facts are exemplified using speech signals and the RLS algorithm.

In this paper, we propose a construction of lattices in dimension 8n via orders in an octonion algebra over a totally real number field. Using this construction, we present rotated versions of E8 and Λ16 lattices that are the densest lattices in dimension 8 and 16, respectively.

The use of wireless technology in industrial networks has a high challenge due to the expected quality requirements. Effects such as delay and noise can affect the performance of a wireless network. The loss of packets during data transmission is one of the main defects that can influence the operation of an industrial plant. In this sense, the...

In this paper is demonstrated that the design and scaling of signal constellations for 4D modulations can be parameterized using discrete Hopf fibration. Through examples, the sampling of discrete Hopf fibers provided important complementary information about the signal space of these modulations.

Algoritmos adaptativos devem idealmente apresentar uma alta taxa de convergência, um bom desempenho em regime permanente e um baixo custo computacional. Poucos algoritmos conseguem atender simultaneamente a estes requisitos. Este artigo propõe um problema de otimização local e determinístico cuja solução dá origem a um algoritmo adaptativo que...

This article presents an study of interference from malicious frequency modulated signals in a OFDM based communication system under presence of a fading channel. By means of simulations, the efficiency of attacks against the OFDM system with a malicious signal easly obtained by analog modulation is verified.

Este trabalho propõe uma metodologia para construção de sistemas de comunicação baseados na topologia do atrator caótico de Lorenz. Sua implementação é baseada na relação entre o fluxo caótico gerado pelas equações que definem o sistema e um diagrama de estados, construído a partir de uma seção de Poincaré. É definido um mapeamento entre sequências...

This paper presents the development of a transceiver for nanosatellites. The main goal is to propose a circuit that receives the uplink signal at 401 MHz and retransmits it to the downlink channel at 2.26 GHz. The paper presents the following topics: operation scenario of the nanosatellite, dimensioning of the system blocks, and characterization.