Ultrafast ultrasound imaging using simultaneous emission of plane waves with random phases

Victor H. R. Machado, Tatiana de Almeida Prado, Thiago Passarin, Glauber Brante, Joaquim Maia, Daniel Rodrigues Pipa

DOI: 10.14209/sbrt.2023.1570923528

Keywords: Ultrafast ultrasound Coded signals Plane-wave Imaging

Abstract

Plane-wave Imaging (PWI) is used in ultrasound to insonify the region of interest to visualize it as an image. In PWI a diversity of angles and a much higher wavefield is used than in the common synthetic aperture approach. For good imaging, many plane wave emissions are required. To reduce the emission time, the concept of simultaneous emission of plane waves coded with specific patterns is used. In this particular work, is employed a technique that involves encoding the signals using random phases, with the objective of separating them using a matched filter.

Download

Elaboração de material absorvedor de radiação eletromagnética poroso baseado em compósitos magnéticos para a banda X

Ábda Moriá S. Cunha, Felipe M Yamamoto, Gabriel De Azevedo Carvalho Reis

DOI: 10.14209/sbrt.2023.1570923549

Keywords: Banda X Compósitos magnéticos Ensaio de refletividade Analisador de redes vetorial

Abstract

O trabalho a seguir foi desenvolvido com o intuito de descrever o desenvolvimento de materiais absorvedores porosos baseados em compósitos magnéticos para a banda de frequências X. A espuma proposta se baseia em um compósito magnético baseado na dispersão de um aditivo magnético em uma matriz dielétrica de borracha de silicone. Foi induzida a inserção de porosidade no material, realizada por meio da cura da borracha de silicone sob determinado nível de vácuo. A avaliação do desempenho do material final foi realizada através do método do guia de ondas na configuração do ensaio de refletividade, auxiliado por um analisador de redes vetorial.

Download

High-Frequency Surface Wave Radar Performance Analysis for CA-CFAR Algorithm in K-distributed Clutter

Diego da Silva de Medeiros, Rômulo Fernandes da Costa, Naiara Tieme Mippo, Dimas Irion Alves, Renato Machado

DOI: 10.14209/sbrt.2023.1570923553

Keywords: High-frequency surface wave radar Radar simulation Performance analysis K-distribution

Abstract

This paper analyzes the performance of a cell-averaging constant false alarm rate (CA-CFAR) algorithm designed for K-distributed clutter in High-Frequency Surface Wave Radar applications (HFSWR). Due to complex scattering mechanisms, the clutter returns in the range-Doppler spectrum are highly non-homogeneous. This study compares a closed-form probability of detection of the K-distribution CA-CFAR to a numerical simulation of sea clutter based on a physical sea radar cross-section (RCS) model, which considers wind conditions and operating parameters. The simulation shows that the closed-form analytical expression acts as an upper bound for detector performance, which is degraded in practice by the strong peaks of the clutter power.

Download

Pilot Allocation and Assignment Optimization in User-Centric Distributed Massive MIMO Networks

Thaissa Toyomi Rocha Ueoka, Michael André Sousa Costa, Daynara Dias Souza, Marx Miranda de Freitas, André Fernandes, Gilvan Soares Borges, Andre Mendes Cavalcante, Joao Weyl Costa

DOI: 10.14209/sbrt.2023.1570923555

Keywords: Cell-free massive MIMO channel estimation genetic algorithm pilot allocation and assignment

Abstract

Distributed massive multiple-input multiple-output (MIMO) networks, also known as cell-free, are promising solution to increase efficiency in beyond 5G systems. Pilot-based uplink (UL) channel estimation directly influences transmission efficiency, as it is used to mitigate interference and noise from user equipment (UEs). In this context, this work uses genetic algorithm (GA) as a tool to optimize pilot allocation and assignment and maximize spectral efficiency (SE). First, we define the optimal amount of samples allocated to channel estimation that balances accuracy and overhead. Generally, this lead to fewer pilots than UEs. Therefore, the pilot assignment is also optimized to decrease interference between UEs reusing the same pilot. The results show that the optimal number of pilots presents a similar behavior when the number of UEs increases. The average SE is improved when GA is used to optimize pilot assignment compared with the baseline solution

Download

Estudo da Aplicação da Simetria de Penrose no Plano de Terra das Antenas de Microfita

Humberto Dionísio de Andrade, Bruno Rodrigues Fialho, Emerson Nunes dos Santos, Francisco Monteiro Sobrinho, Isaac B. T. da Silva, Leonardo Oliveira de Sousa, Nickson S Oliveira Lopes

DOI: 10.14209/sbrt.2023.1570923561

Keywords: Antennas Microstrip Penrose Almost Periodic

Abstract

This article presents an investigation of the effect of applying Penrose symmetry on microstrip antenas, evaluating the influence on the radiation parameters from changes in the dimensional values of this type of structure. This quasi-periodic model will be applied to the antena ground plane for an operating frequency of 2.45GHz. The variation of the radius of the quasi-periodic Penrose symmetry in the ground plane of the antena will be analyzed. The measured and simulated results validate the influence of this arrangement on the antena radiation parameters, increasing gain and bandwidth.

Download

Implementação de um Sistema Híbrido FiWi utilizando FSO, VLC e Ondas Milimétricas para Aplicações 6G

Celso Henrique, Luiz Augusto Melo Pereira, Tomas P V Andrade, Evandro Conforti, Arismar Cerqueira S. Jr.

DOI: 10.14209/sbrt.2023.1570923562

Keywords:

Abstract

Neste trabalho, avaliamos experimentalmente uma arquitetura híbrida FiWi (fiber/wireless) que combina fibra óptica, (FSO, free space optical), ondas milimétricas e (VLC, visible light communication) em uma mesma topologia de rede. Para o fronthaul, um enlace de 20 km de fibra óptica seguido por um enlace FSO de 1,5 m foi implementado. Para o acesso, um enlace 5G NR sem fio de 2 m operando em 39 GHz e um enlace VLC ponto-a-ponto de 3 m em 550 MHz garantiram uma vazão de dados total do sistema na ordem de 1,5 Gbit/s, atendendo aos requisitos do 3GPP Release 18.

Download

Detecção de Constituinte Prejudicial em um Aço pela Aplicação da Decomposição Empírica de Modos

Emilly J. B. Duarte, Edgard Silva, Suzete Correia, Suelen Lima de Carvalho Alencar, João Batista de Oliveira Silva

DOI: 10.14209/sbrt.2023.1570923568

Keywords: Decomposição Empírica de Modos Ruído Magnético de Barkhausen Ensaio Eletromagnético

Abstract

Barkhausen Magnetic Noise analysis has been carried out to monitor constituents harmful to the properties of ferromagnetic materials. Empirical mode decomposition has been applied to decompose complex signals into simpler components. In the present work this is applied to detect the harmful constituent sigma in a stainless steel. Samples both without and with 4% Sigma were used. Waves with frequencies of 5 Hz, 10 Hz, and 20 Hz were applied, and the noise analysis was compared with the microstructures. The results indicate that the first intrinsic mode function is effective in extracting information from the electromagnetic test noise.

Download

Detecção de movimentação atípica de bovinos através da monitoração da intensidade de sinais de radiofrequência

Rafaela T. F. de Freitas, Pedro A. Ribeiro, Pedro R. Chaves, Omar C. Branquinho, Paulo Cardieri, Luiz C. R. Junior, Weber V. B. Soares, Alexandre Tizzei, Raphael M Assumpção

DOI: 10.14209/sbrt.2023.1570923569

Keywords: WSN Wireless Abigeato RSSI

Abstract

Cattle theft is a national and growing problem in Brazil. It is known that, during theft, animals move atypically, changing the conditions of propagation in the environment, impacting the amplitude of the radiofrequency signals received at the location. In this paper, we investigate the feasibility of using the observation of radiofrequency signals received in the environment as a method of detecting thefts. Preliminary results of field tests, conducted on a cattle farm, indicated that the behavior of radiofrequency signals reflects the behavior of animals, presenting a promising potential for the detection of cattle theft.

Download

Design, Deployment, and Validation of a Low-Cost IoT Platform based on LoRa for Precision Dairy Farming

Guilherme Pires Pieadade, Samuel Mafra, Danilo Machado de Oliveira, Mateus R Cruz

DOI: 10.14209/sbrt.2023.1570923572

Keywords: Dairy Farming Internet of Things LoRa Network Wireless Sensors Network

Abstract

Precision farming has become essential for increasing food production in the previously used cultivation area. Therefore, animal health monitoring and estrus detection are essential to increase dairy farming production. Wireless Sensor Networks play an important role in replacing manual methods impractical for large herds, and they can be used to collect a large amount of data in real-time. Furthermore, long-range transmission techniques can be used on large farms. This paper proposes applying and validating a Wireless Sensor Network integrated with a database and long-range communications techniques capable of monitoring the dairy herd, generating health, estrus, and theft alerts. The results achieved by integrating system elements, such as the LoRa gateway, MongoDB database and dashboard, demonstrate the viability of the proposed WSN.

Download

Estudo da Cobertura da Rede de Fibra Óptica nos Municípios Brasileiros sob a luz de Algoritmos Exato e Heurístico

Fausto Luiz J Padua, Edson Luiz F Senne

DOI: 10.14209/sbrt.2023.1570923574

Keywords: Telecomunicações fibra óptica municípios rotas

Abstract

Dos 5570 municípios brasileiros, ainda há 1309 municípios sem conexão à Internet por fibra óptica, o que levanta a seguinte questão: qual a melhor forma de investir nessa cobertura para os municípios? Este estudo buscou, através do cálculo da Árvore Geradora Mínima com algoritmos exato e heurístico, trazer alguma luz à questão. Foi realizado o cálculo do custo mínimo para a cobertura, com pelo menos um enlace, entre todos os municípios brasileiros, bem como em cenários menores, como cada estado do Brasil. Por fim, foi realizada uma comparação da precisão e eficiência entre os diferentes algoritmos escolhidos e apresentados os resultados.

Download