Avaliação de Redes OSPF com Roteamento Sensível ao Contexto e Aplicação de Conceitos SDN

Vitor S. Goulart, Luiz F. G. de Oliveira, Jorge G. S. dos Santos, Ugo S. Dias, Rafael T. de Sousa Jr

DOI: 10.14209/sbrt.2018.211

Keywords: Internet das coisas Redes Definidas por Software Redes de Sensores Roteamento Sensibilidade ao Contexto Sensoriamento Distribuído

Abstract

Este artigo propõe uma nova abordagem para o uso de medições obtidas por sensores em redes de computadores, com aplicação em topologias de Internet das Coisas (IoT) e em redes definidas por software (SDN). O desempenho da abordagem proposta é comparado a uma típica topologia de rede OSPF tradicional. O papel do processamento distribuído das informações de contexto e a inferência típica de ambientes IoT, bem como uma proposta para a ampliação do uso de dados de sensores em redes de computadores formam o tema central deste trabalho.

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Simple and Robust Method for OFDM Performance Improvement with Nonlinear Amplification

Robson F. de Moraes, Roberto C. G. Porto, Ernesto L. Pinto

DOI: 10.14209/sbrt.2018.263

Keywords: bit error rate (BER) performance orthogonal frequency division multiplexing (OFDM) peak-to-average power ratio (PAPR) solid state power amplifier (SSPA) partial transmit sequence (PTS)

Abstract

This work proposes a new technique to be used in orthogonal frequency division multiplexing (OFDM) systems subject to nonlinear power amplification, aiming to obtain better bit error rate (BER) performance with reduced computational complexity and low peak-to-average power ratio (PAPR). The core of the proposed technique is a new metric to choose a modified OFDM symbol to be transmitted among several alternatives with the aim of reducing the deleterious effects of nonlinear amplification. The proposed metric is independent of a power amplifier model and may be associated with different approaches to generate the modified OFDM symbols. Simulation results are presented, using a Partial Transmit Sequence (PTS) approach, which show that the proposed scheme provides BER performance similar to other known techniques at a significantly lower computational cost (about 33% less real multiplications and 66% less real additions). Estimates of the PAPR complementary cumulative distribution function (CCDF) are also presented and show that the proposed method does not degrade this performance index substantially compared to those techniques.

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Sensoriamento Espectral Cooperativo via Teorema dos Círculos de Gerschgorin sob Ruído Impulsivo

Lucas dos S. Costa, Dayan A. Guimarães, Rausley A. A. de Souza

DOI: 10.14209/sbrt.2018.264

Keywords: Cognitive radio GRCR impulsive noise spectrum sensing

Abstract

The GRCR (Gerschgorin radii and centers ratio) detector was recently proposed for application in spectrum sensing for cognitive radio systems. Its main attributes are the low complexity and the robustness against nonuniform and dynamical thermal noise and received signal power. This article evaluates the performance of the GRCR under the influence of impulsive noise and proposes a technique to mitigate this noise by nulling the corrupted samples. Simulation results show that the GRCR alone is not robust against impulsive noise, and that the proposed mitigation technique can make it practically insensitive to such a impairment.

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Applicability of an output-only structural damage detection based on transmissibility measurements and kernel principal component analysis

A. Santos, M. F. M. Silva, R. Santos, E. Figueiredo, N. M. M. Maia, J. C. W. A. Costa

DOI: 10.14209/sbrt.2018.260

Keywords: Structural health monitoring Transmissibility measurements Damage detection Kernel principal component analysis

Abstract

Frequency response functions have been employed as damage-sensitive features in the vibration-based structural damage detection. The need for measuring the excitation forces arises as a remarkable limitation on the application of those features in real-world applications. Transmissibility measurements can be explored as features with output-only nature, which imply the need for measuring only the response signals. Thus, an output-only damage detection method is proposed, combining transmissibilities with kernel principal component analysis. The results performed on transmissibility measurements from a laboratory steel beam reveals that the output-only method has high potential to be applied in a wide range of monitoring solutions.

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Estudo comparativo dos modos da PPG para medição de sinais de FC utilizando Arduino

Valdez Aragão de Almeida Filho, Anselmo Mendes Oliveira, Catarina da Silva Costa

DOI: 10.14209/sbrt.2018.212

Keywords: photoplethysmography heart rate electric circuit Arduino

Abstract

This paper presents a comparative study between the transmission and reflection modes of photoplethysmography to measure heart rate signals. In this study, a circuit for heart rate acquisition and measurement was developed, which was integrated to the Arduino to process those signals. Samples of three different individuals were analyzed, and the results showed that the reflexive mode of PPG has a greater stability when measuring HR.

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Análise da sintonia de uma antena monopolo HF em viatura tática de comando e controle

Maurício H. C. Dias, Arnaud C. Silveira, Márcio B. T. Dantas

DOI: 10.14209/sbrt.2018.261

Keywords: Antenas monopolo antenas HF comando e controle comunicações HF rádio definido por software

Abstract

Viaturas táticas são um recurso usual em sistemas de comando e controle. Para o adequado estabelecimento dos enlaces de comunicações, é importante conhecer o desempenho das antenas instaladas no veículo. Este trabalho analisa uma antena monopolo HF em diferentes comprimentos e inclinações no topo de uma viatura tática. Com relação ao caso do monopolo ideal de λ/4, verificou-se que a frequência de ressonância ocorre até 20% abaixo da esperada. A inclinação deslocou essa frequência em até ±5%. O diagrama de ganho manteve aspecto geral onidirecional, com queda de aproximadamente 10 dB próximo à direção vertical, em duas inclinações.

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Comparaçãode Janelas de Amortecimento Aplicadas à Solução de Equações Parabólicas no Domínio do Tempo

Hugo Daniel Melo Ferreira, Cássio Gonçalves do Rego, Gláucio Lopes Ramos

DOI: 10.14209/sbrt.2018.262

Keywords: Parabolic Equation Nonhomogeneous Atmosphere Cranck-Nicolson Method Damping Windows

Abstract

In this work, a formulation was developed for parabolic equations in the time domain (TDPE), considering nonhomogeneous atmosphere and disregarding backscattering. The formulation uses as base the frequency domain and through a special Fourier transform defined by Popov there is the conversion to the time domain. The Cranck-Nicolson method is used for numerical analysis of the finite difference formulation. The simulations were performed considering irregular, real relief and different types of damping windows such as Hanning, Hanning-Poisson, Hamming and Kaiser Window as a way to analyze the one that performs better.

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Estudo paramétrico de antena patch retangular com anel fendido

Francisco José Dantas de Oliveira, Idalmir de Souza Queiroz Júnior, Humberto Dionísio de Andrade, Bruno Rodrigues Fialho, Xisto Lucas Travassos Junior, Glauco Fontgalland

DOI: 10.14209/sbrt.2018.152

Keywords: Rectangular patch antenna Ground plane truncation Parametrization Ring slot antenna

Abstract

This article presents a rectangular patch antenna initially designed for the frequency of 5.8 GHz with truncated ground plane and a rectangular slot in the patch in order to verify the influences of these changes in antenna radiation behavior. The purpose is to parametrically analyze the effect of the change in ring widths as well as compare with a standard rectangular patch antenna. It was demonstrated that the frequency of operation, antennas bandwidth was altered and, in some cases, the antenna presented new resonant modes.

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Restauração de Imagens com Redes Neuronais

Lucas A. Rodrigues, Renato Candido, Magno T. M. Silva

DOI: 10.14209/sbrt.2018.267

Keywords: Processamento de imagens restauração de imagens rede neuronal aprendizado de máquina

Abstract

A restauração de imagens busca eliminar as distorções causadas no processo de aquisição. Neste artigo, utiliza-se uma rede neuronal MLP (Multilayer Perceptron) para restaurar imagens que contêm quatro tons de cinza e que foram degradadas por uma função gaussiana.

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Utilização da Lógica Fuzzy em Redes PON Definidas por Software

Ricardo Girnis Tombi, Michael Prieto Hernández, Regina Melo Silveira

DOI: 10.14209/sbrt.2018.273

Keywords: PON Software Defined Networks Fuzzy Logic.

Abstract

Passive optical networks (PON) have been increasingly used by telecom operators as access networks and have well-defined resource control mechanisms for downstream and upstream traffic. However, the integration of other technologies such as Fuzzy logic and software defined networks (SDN) can be used as an alternative to optimize or increase the performance of these access networks. This work demonstrates the use of Fuzzy logic for resource allocation in PON networks, and presents how it can be flexible and simple implementation in conjunction with an SDN architecture considering different types of traffic generated by IoT (Internet of Things), voice and video applications, which have specific needs. The results obtained prove the feasibility of Fuzzy logic to subsidize the control of resource allocation, guaranteeing the quality of services in PON.

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