Semi-Supervised Receiver for MIMO Systems with Mixed Khatri-Rao-Kronecker Coding

Amarilton Lopes Magalhaes, Paulo Gomes, André de Almeida

DOI: 10.14209/SBRT.2020.1570661676

Keywords: MIMO constrained PARAFAC model MKronST coding

Abstract

In this work, we propose a Multiple Kronecker product-based Space-Time (MKronST)-based coding for single-hop point-to-point Multiple-Input Multiple-Output (MIMO) systems that employ space-time spreading scheme whose certain number of data streams are spatially spread within the antennas of a subarray while other ones are spread across antennas of different subarrays. Capitalizing on a tensor formalism, the received signals are modelled as a constrained quadrilinear PARAllel FACtor (PARAFAC) model, which allows us to derive a semi-supervised iterative receiver for joint symbol and channel estimation. Simulation results are provided to evaluate the performance of the proposed receiver. Our numerical results show that the proposed semi-supervised receiver is capable of jointly estimating the symbol and channel matrices with a superior performance in comparison to competing receivers outlined in the literature.

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Design and Optimization of a TEM Coaxial Horn for Wideband Operation in Millimeter Waves

Elígia Simionato, Rafael Abrantes Penchel, Sandro R. Zang, Ivan Aldaya

DOI: 10.14209/SBRT.2020.1570661682

Keywords: Millimeter Waves Coaxial Horn Wideband Antennas

Abstract

This work explores a framework of numerical techniques to design a wideband TEM coaxial horn for millimeter waves operation. Firstly, aperture dimensions and flare angle were determined to avoid nulls in vertical radiation pattern at θ<55°. Then, a transition to 2.92mm connector and a dielectric support for the central conductor are proposed. To enhance electromagnetic performance, Genetic Algorithm (GA) was used to optimize the transition and support dimensions. To address the antenna performance, full-wave electromagnetic analysis based on Finite Element Method was employed. The designed model presented frequency bandwidth larger than 45% (25-40 GHz) with return loss greater than 20dB.

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PA5Ge - Implementação de uma Rede Celular Privada com Funcionalidades 5G no Campus da UFPA

Lauro Castro, Aldebaro Klautau, Cleverson Nahum, Ilan S Correa, Leonardo Ramalho

DOI: 10.14209/SBRT.2020.1570661684

Keywords: 4G 5G Community

Abstract

This article presents the current stage of the implementation of the PA5Ge, which is a mobile network based on functionalities of the fourth (4G) and fifth (5G) generations, licensed for scientific and experimental purposes in the 700 MHz band. The PA5Ge has modern features such as virtualization of network functions (VNFs) and architecture of Centralized Radio Access Network (C-RAN). One of its objectives is to serve as an experimental platform for academic research in 5G and future networks (B5G). Another objective is to generate know-how for the future use of 4G/5G resources on community networks in locations far from urban centers and not served by commercial operators. In this context, the main contribution of the article is the project description and its steps on the implementation of PA5Ge, encompassing licensing aspects to technicians in order to foster similar initiatives to establish platforms for experimental research in 4G/5G and in the scope of humanitarian engineering through telecommunications.

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Aplicação do espectro marginal de Hilbert na análise de desvios vocais

T M Bezerra, J. F. Souza, Maísa L F Santos, Silvana Cunha Costa, Suzete Correia

DOI: 10.14209/SBRT.2020.1570661686

Keywords: Acoustic analysis Hilbert Marginal Spectrum vocal deviations

Abstract

In this work, the amplitude-frequency graphs provided by Hilbert's marginal spectrum are used to characterize both healthy voice signals as those with vocal deviations: roughness, breathiness and strain. The results demonstrate that the obtained patterns seem to be appropriate to differentiate the analyzed signals.

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Códigos de Bloco Espaço-Tempo Diagonais 2 × 2 com Boas Densidades Normalizadas

Carina Alves, Cintya W. O. Benedito, João Gabriel Oliveira de Jesus

DOI: 10.14209/SBRT.2020.1570661687

Keywords: Densidade normalizada Códigos diagonais Matriz geradora

Abstract

In this work we prove that the diagonal space-time block code 2 × 2 with minimum determinant 1 based on an irreducible quadratic polynomial x^2+ζ_3-1 over Q(ζ_3) is optimal in terms of normalized density. We also present diagonal space-time block codes 2 × 2 with minimum determinant 1 based on irreducible quadratic polynomials over Q( √ d), d = −2, −7 that have good normalized densities.

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Dynamic Bayesian Approach Applied in Link Adaptation Problem for Fifth Generation Network

Hitalo J.B. Nascimento, Francisco R. P. Cavalcanti, André de Almeida, Mateus Pontes Mota

DOI: 10.14209/SBRT.2020.1570661689

Keywords: Adaptive modulation and coding Link adaptation Bayesian network

Abstract

With technological development, wireless communication has been one of the fastest growing fields of Computing and Engineering in recent years. This fact requires that new approaches be developed to ensure better performance and reliability in wireless communication. In this paper a new approach has been proposed as a solution to the problem of adaptive modulation and coding (AMC), through the development of an extension of the method naive Bayesian classifier, known as dynamic naive Bayesian classifier, to maximize spectral efficiency. The proposed approach exhibits a better performance than k-nearest neighbours algorithm and the traditional Look-Up table solution, with average classification error 2.85%, which represents approximately 10% with respect to the most similar method.

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Reconhecimento de placas de sinalização via processamento de imagens

Mathias Silva, Diego da Silva de Medeiros, Deise Arndt

DOI: 10.14209/SBRT.2020.1570661692

Keywords: Placas de sinalização Processamento de imagem HOG SVM

Abstract

This paper presents the study and developing of a traffic signs recognition system, using image processing techniques. The system was trained and tested in a public image database, and then, validated in image captured by a moving car. The system has achieved 70% of traffic signs recognized.

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Identificação de lesões periapicais em exames de radiografia utilizando clusterização baseada na \varphi-divergência e algoritmos de classificação

Joniel B Barreto, Danilo A Oliveira, Rui F Vigelis, Iális Paula Jr.

DOI: 10.14209/SBRT.2020.1570661694

Keywords: Visão computacional Segmentação Lesões periapicais

Abstract

O presente trabalho desenvolve uma metodologia para identificar lesões em imagens de radiografias periapicais utilizando os classificadores KNN e MLP em conjunto da clusterização baseada na \varphi-divergência como método de segmentação. Também é comparado duas técnicas de balanceamentos de dados, Tomek Link e o Random Under Sampling. Com base nos resultados obtidos observa-se que embora ambos classificadores tenham sido eficazes para identificação das lesões, o KNN se mostrou mais eficiente do que a MLP, com acurácias de 90,12\% e 75,99\%, respectivamente, para a técnica Tomek Link que se mostrou mais aplicável que o Random Under Sampling.

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Análise do ruído magnético de Barkhausen por meio da transformada wavelet discreta para detecção de microestrutura fragilizante em um aço

Ibernon Barros, Edgard Silva, Suzete Correia, José Carvalho F.

DOI: 10.14209/SBRT.2020.1570661697

Keywords: Wavelet Ruído magnético de Barkhausen Fragilização

Abstract

Ensaios eletromagnéticos não destrutivos vêm sendo desenvolvidos para acompanhamento de formação de microestruturas deletérias em materiais ferromagnéticos. No presente trabalho, o ruído magnético de Barkhausen resultante da interação entre ondas emissoras de 5 Hz e um aço inoxidável duplex é estudado através da transformada wavelet discreta. Os resultados foram comparados com medidas de energia absorvida por impacto e microscopia óptica. As medidas de RMS dos sinais com duas famílias wavelet mostraram ser eficazes na detecção da formação de precipitados nanométricos no interior do material, que levam à fragilização do material em estudo.

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Um Estudo sobre um Duopólio em uma Rede Óptica Elástica

Victor P Sousa, Rodrigo Campos Bortoletto

DOI: 10.14209/SBRT.2020.1570661703

Keywords: Telecomunicações Cadeia de Markov Duopólio Simulação

Abstract

Resumo- Na última década o aumento do consumo de largura de banda pelos usuários impulsionou o surgimento de novas tecnologias para os sistemas de comunicações ópticas. Dentre essas novas tecnologias é possível destacar as Redes Ópticas Elásticas, que tem como principal mudança de paradigma a alteração da grade fixa até então presente nas redes WDM. Este trabalho tem o objetivo de desenvolver um modelo matemático que permita estudar um duopólio em enlace único utilizando as Redes Ópticas Elásticas e compreender a influência do comportamento dos usuários na divisão de tráfego entre as duas operadoras. Palavras-chave - Cadeia de Markov, Telecomunicações, Simulação, Duopólio.

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