Wirtinger Calculus and Complex Natural Gradient Algorithm

Rafael Carvalho Bluhm, Charles Casimiro Cavalcante

DOI: 10.14209/sbrt.2022.1570823148

Keywords: Wirtinger calculus adaptive filters

Abstract

This paper presents an extension of the real tangent spaces on the form of the Wirtinger (complex) calculus in order to find a generalized expression for the natural complex gradient. It is presented an expression for the natural gradient, which is valid to a general coordinate system, expressed in a complex basis, allowing the use of of the fully complex notation. The equivalence of complex and real representations is done through the complex structure that real spaces may have, allowing the change of the used basis. Some examples typical applications are presented, illustrating the potential of the proposal.

Download

Hybrid Power Line/Wireless Systems: Analyses of Normalized SNRs for In-home Broadband Scenarios

Nathan Cravo, Mateus Filomeno, Moises Vidal Ribeiro

DOI: 10.14209/sbrt.2022.1570823150

Keywords:

Abstract

This paper analyzes the normalized signal-to-noise ratios (nSNRs) of power line and wireless media to evaluate the suitability of hybrid power line/wireless systems in in-home broadband scenarios. In this sense, we assume that the transmitter node knows the channel state information, and then we seek to find the level of diversity between power line and wireless medium based on the amount of nSNR intersections in the frequency domain. In the numerical analysis, we show that power line and wireless media present nSNRs intersections in several scenarios. Moreover, we verify that greater diversity is found with the distance increasing, which favors hybrid power line/wireless systems.

Download

Conectividade IoT para Áreas Remotas baseada em CubeSats e PoF

João Antiquera, Gabriel Henrique Barros Damasceno, Letícia Souza, Arismar Cerqueira S. Jr.

DOI: 10.14209/sbrt.2022.1570823153

Keywords: CubeSats IoT PoF

Abstract

Este trabalho apresenta o estudo e implementação de uma prova de conceito referente a uma topologia de rede de Internet das Coisas (Internet of Things - IoT) para áreas remotas baseada nas tecnologias CubeSat e Power-Over-Fiber (PoF). Propõe-se um cenário dividido em três partes: centro urbano, comunicação via satélite (CubeSat) e área remota. O principal foco deste estudo é a implementação do CubeSat e área remota. Para tal, utiliza-se a tecnologia PoF para alimentar um microcontrolador e um transceptor de RF, minimizando assim o custo de infraestrutura do projeto.

Download

Magnetoplasmonic Dipole Nanoantenna for Reconfigurable Optical Communications

Gabriel Henrique Barros Damasceno, William O. F. Carvalho, Arismar Cerqueira S. Jr., Jorge Ricardo Mejía-Salazar

DOI: 10.14209/sbrt.2022.1570823160

Keywords: 6G Beam steering Magnetoplasmonic Nanoantennas

Abstract

We show that magneto-optical (MO) effects in magnetoplasmonic dipole nanoantennas, built by plasmonic ferromagnetic materials, enable active beam steering of the radiated fields. Our design, working at the visible wavelength λ=690nm, is promising for applications in intra- and inter-chip reconfigurable optical nanolinks for future 6G communication networks.

Download

Projeto de Circuito Beamformer para Antenas com Dupla Polarização Circular

Danielle O. A. Sieber, Juner M. Vieira, Ildefonso Bianchi, Daniel Basso Ferreira, Daniel Nascimento, Felix Antreich

DOI: 10.14209/sbrt.2022.1570823172

Keywords: Beamformer circuit Circular polarization GNSS receivers Sinuous antenna

Abstract

This paper presents the design of a beamformer circuit for dual circularly polarized antennas composed of four sequentially rotated radiators. The beamformer operates over the L band, and its architecture has two 180-deg hybrid couplers, one 90-deg hybrid coupler, and two low-noise amplifiers. Commercial components are selected to build the circuit prototype, and its scattering parameters are measured. The prototype is used to feed a sinuous antenna designed to receive GNSS signals. The antenna measurements show that the broadside axial ratio is below 2.25 dB from 1 to 2 GHz, thus validating the beamformer operation.

Download

Complex Network Analysis of the Relationship Between Reactive Routing and MANET Performance

Diego B Santi, Julio C N Borges, Mauro Fonseca, Klaus Wehmuth, Anelise Munaretto, Ricardo Lüders

DOI: 10.14209/sbrt.2022.1570823188

Keywords: Mobile ad hoc network routing protocol performance evaluation complex network

Abstract

Reactive routing protocols of MANETs create routing tables whose paths can be represented by a routing network, i.e. the network of links created from routing tables that can change over time. These links are created and destroyed according to the mobile behavior of nodes. Different topologies of the routing network impact the performance of a MANET measured by typical indicators such as PDR (Packet Delivery Rate) and E2E (End-to-End) delay. This work aims at investigating the relationship between the routing network and MANET performance indicators. It is accomplished by representing the routing network as a complex network which is characterized by metrics such as average degree, density and clustering coefficient. The evaluation of a MANET is implemented using OMNeT++, and the Ad hoc On Demand Distance Vector (AODV) routing protocol. The results present the performance indicators and complex network metrics for different speed and number of nodes as well as their correlations. They show a strong negative correlation between PDR and both density and clustering coefficient. However, a strong positive correlation between E2E delay and degree, density and clustering coefficient is observed.

Download

Desenvolvimento de um CubeSat para Mapeamento de Radiação Gama em Órbita Baixa

Diego Anestor Coutinho, Sthefany Vilela, Arielli da Conceição, Pedro Lucas Siqueira Paulino, Guilherme Pedro Aquino, Evandro Cesar Vilas Boas

DOI: 10.14209/sbrt.2022.1570823215

Keywords: CubeSat universitários pequenos satélites órbita baixa radiação gama

Abstract

Esse trabalho apresenta o desenvolvimento de um pequeno satélite do tipo CubeSat padrão 1U para missão de sensoriamento e mapeamento dos níveis de potência de radiação gama em órbita baixa. Objetiva-se a captura dos dados em diferentes posições dentro da órbita do satélite para a construção de um mapa de calor. Relata-se a fase de prototipação, desenvolvimento e testes com os subsistemas integrados em uma estrutura mecânica em padrão 1U. Realizou-se a caracterização física, mecânica, magnética, térmica e de transmissão como forma de avaliar o desempenho do protótipo final, sendo os resultados satisfatórios com as condições de testes.

Download

Nova proposta para quantificação de QoS em função das características de configuração LoRaWAN

Cristiano Neri da Silva, Jocines Silveira, Pedro Felipe de Abreu, José dos Reis Jr.

DOI: 10.14209/sbrt.2022.1570823468

Keywords: LoRaWAN QoS FCM K-Means

Abstract

This paper proposes to determine the number of different Quality of Service (QoS) by analyzing the characteristics of the set of LoRaWAN configurations by combining the gap statistic with Fuzzy C-Means (FCM) and elbow with K-means algorithm methods. Additionally, grouping was performed with FCM based on the Bit Error Rate (BER), Received Signal Strength Indicator (RSSI), and Time on Air (ToA) metrics. The results determined appropriate groupings according to the different types of QoS based on the combination of methods, while FCM allowed grouping the applications with similar QoS.

Download

Análise Acústica Vocal e Classificação de Vozes com Patologias Laríngeas

Laysa de Freitas Marques Holanda, Francisco Jose Alves Aquino

DOI: 10.14209/sbrt.2022.1570823556

Keywords: Análise acústica patologias laríngeas machine learning SVM

Abstract

Com o propósito de pré-diagnóstico de patologias laríngeas com um método não invasivo, este trabalho apresenta a análise de medidas acústicas vocais como parâmetro de entrada para um sistema de classificação baseado em SVM, sendo eles frequência fundamental, formantes, energia e entropia, Este classificador foi capaz de classificar vozes saudáveis de patológicas e as patologias Edema de Reinke e Disfonia.

Download

Geração de Pentes Ópticos de Frequências Amplos e Ultra Planos por Moduladores Eletro-ópticos Cascateados

Leonid Huancachoque, Aldário Bordonalli

DOI: 10.14209/sbrt.2022.1570823625

Keywords: electro-optic modulation optical frequency comb optical source optical superchannels

Abstract

An optical comb frequency generator with a large number of equalized lines by the efficient modulation of a cascade of electro-optic modulators is proposed. Modeling of the array allowed theoretical analysis of the performance and determination of the driving conditions for empirical testing of the modulators. In an array with one phase modulator followed by three dual-control Mach-Zehnder modulators, the theoretical analysis produced combs with up to 65 equalized spectral lines. In an experimental test with one modulator of each type and the same arrangement, a comb of 25 equalized lines was obtained, which is consistent with theory.

Download