XXXVIII Simpósio Brasileiro de Telecomunicações e Processamento de Sinais

Chaos-based communication systems (CBCSs) can be used in applications that require security, such as image coding. In this paper, we code an image using a CBCS and assess the quality of this coding by measuring the percentage mean square error (%MSE). The obtained results show that the image coding with this system is secure, when the adequate parameters...

This work presents a theoretical and experimental investigation on the properties of microstrip antenna arrays based on the tetra circle fractal. An antenna was analyzed with a resonator patch for the Bluetooth and Wi-Fi frequency, later, more patches identical to the horizontal axis logo were added, forming analyzed arrays. For the study, arrangements...

In this work, we evaluate the average age-of-information (AoI) of a network composed of an internet-of-things (IoT) end-device (ED) transmitting randomly generated status updates to an access point (AP). More specifically, we elaborate on a recently proposed truncated automatic repeat request (TARQ) scheme, by considering a buffer-aided AP that is...

This work applies Bayesian optimization in the automatic adjustment of hyperparameters for classification of motor imagery in brain-computer interfaces. The strategy consists of modeling the accuracy of the classifier according to the hyperparameters and seeking an optimal personalized setup. Simulations from public data resulted in an average...

This paper presents the modeling and performance results resulting from the conjunction of the MIMO scheme with the Generalized Frequency Division Multiplexing (GFDM) and with Index Modulation techniques in order to obtain an increase in the spectral and energy efficiencies without excessive increase in the computational complexity of the system.

LORAWAN is a Low-Power Wide-Area Network specification that recommends using an Adaptive Data Rate (ADR) algorithm to improve the allocation of the network resources. However, typical configurations of the most used ADR algorithm do not suit all applications due to the optimistic link quality estimates used to compute transmission parameters. This paper...

This article presents the implementation of some filters commonly used in the analysis of DICOM (Digital Imaging and Communications in Medicine) computed tomography (CT) images. For this study, the grayscale cone-beam CT mandible images were considered. For analysis purposes, the performance of some filters implemented in MATLAB is compared with filters...

O armazenamento é um dos componentes mais importantes da cadeia de distribuição de vacinas, principalmente pela sensibilidade delas a variações de temperatura, que podem ocasionar diminuição da sua eficácia. Considerando isso, existe uma necessidade de manter constante monitoramento dessa variável, afim de garantir que o produto final venha a manter suas...

Séries temporais são a maneira natural de obter informações sobre sistemas ou processos dinâmicos em uma variedade de aplicações científicas, de engenharia e financeiras. A complexidade dessas pode torna imperativa o uso de métodos baseados em dados. Entre os quais destacamos a técnica de Filtragem por Dinâmica Simbólica, que envolve a determinação de...

Este trabalho apresenta os resultados preliminares do desenvolvimento de um algoritmo de reconhecimento facial em tempo real através de redes neurais convolucionais (CNNs). Elementos faciais, nomeadamente, rosto, boca, nariz e olhos, são detectados pelo algoritmo de Viola-Jones. Cada elemento facial é utilizado para treinar uma CNN. Os resultados de...