Caracterização da Perda de Percurso Indoor de Redes 5G em Ondas Milimétricas

Anderson Fagiani, Arismar Cerqueira Sodré Junior

DOI: 10.14209/sbrt.2017.35

Keywords: 5G comunicações celulares indoor ondas milimétricas propagação.

Abstract

As futuras redes móveis de quinta geração (5G) provavelmente irão operar na faixa de ondas milimétricas, com a finalidade de prover taxas superiores a 1 Gbps por usuário. Este artigo apresenta uma análise experimental da perda de percurso e do coeficiente de propagação em 28 e 38 GHz, que são faixas de frequências consideradas potenciais para sistemas 5G. As medidas foram realizadas em ambientes com propagação indoor. O valor gamma do modelo estatístico de propagação ABG (Alpha-Beta-Gamma) foi utilizado para a caracterização da perda de percurso. Já a estimação do coeficiente de propagação foi obtida por meio da aplicação do método de regressão não linear, por resultar em menor erro quadrático médio (RMSE – Root Mean Square Error).

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Rank-One Tensor Modeling Approach to Joint Channel and Symbol Estimation in Two-Hop MIMO Relaying Systems

Bruno Sokal, André L. F. de Almeida, Martin Haardt

DOI: 10.14209/sbrt.2017.41

Keywords: MIMO systems Cooperative communications tensor decompositions semi-blind receiver

Abstract

This paper proposes two semi-blind receives for joint channel and symbol estimation in MIMO relay-based communication systems. These receivers are developed for a two-hop system, assuming a tensor coding at the source and relay nodes. The central idea of the proposed approach is on the rank-one tensor modeling of the received signal, which allows the use of efficient estimation algorithms. The first receiver utilizes an iterative solution based on the alternating least squares (ALS) algorithm, while the second provides closed-form estimations of the channel and symbol matrices from a truncated higher order singular value decomposition (T-HOSVD). The proposed approach has a lower complexity compared to the receiver developed in a previous work, while providing remarkable performance.

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Attacking and Defending with Intelligent Botnets

Moises Danziger, Marco Aurelio Amaral Henriques , Marco Aurelio Amaral Henriques

DOI: 10.14209/sbrt.2017.259

Keywords: Botnets Machine Learning Autonomous systems Intelligent Agents

Abstract

Machine learning (ML) has been seen as a great ally of security. All his potential to automate actions with some level of intelligence has called the attention of industry which is using it on security systems. However, attackers have also noted all ML potential. In a first moment, attackers have tried to fight MLbased security tools through the study and exploitation of weak points in ML techniques. It is named as adversarial machine learning. Besides this first application, someone could apply a ML-based tool directly against a security system. It is the case of intelligent botnets - a different type of botnet made of relatively intelligent bots which can take decisions by their own during the attack. So, in this work we are making a reflection on the future of botnets within the context of ML and showing that this kind of botnet could break the current detection approaches. We also point out to the need for creating new approaches to combat bots with some kind of intelligence. Moreover, we propose a theoretical model of intelligent bots, their possible impacts and combat strategies.

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Análise do Comportamento Estocástico do Algoritmo KLMS para um Sinal de Entrada Correlacionado

Wemerson D. Parreira, Márcio H. Costa, José C. M. Bermudez

DOI: 10.14209/sbrt.2017.37

Keywords: Adaptive filtering kernel least-mean-square (KLMS) nonlinear system correlated input-signal

Abstract

The Kernel Least-Mean-Square (KLMS) algorithm is a popular algorithm for adaptive nonlinear filtering due to its simplicity and robustness. In kernel-based adaptive filtering with finite order models, the statistics of the linear filter depend on the kernel and its parameters, as well as, on the input vector dictionary update rule that defines the Hilbert space in which the filter operates. The existence of the highly nonlinear relationships between the adaptive filter parameters and the performance criteria makes the design of these filters an almost impossible task without the help of analytical models that predict their performance. Theoretical analyses of the stochastic behavior of the KLMS have already been performed assuming fixed dictionaries and variable dictionaries under the consideration that the temporal sequence of the input vectors is statistically independent. This paper studies the KLMS mean-weight be- havior with Gaussian kernel for variable dictionaries and time- correlated input vectors.

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Correção dinâmica de frequência de transdutores piezelétricos utilizando um sistema computacional inteligente

R.B.Battilana, R.L.Ximenes, M.C.Aranda, F.J.Arnold piezelétricos utilizando um sistema computacional inteligente

DOI: 10.14209/sbrt.2017.42

Keywords: correction frequency intelligent system piezoelectric transducers

Abstract

Dynamic frequency correction systems for piezoelectric transducers can be implemented using techniques with artificial intelligence. This paper presents preliminary results of the implementation of a system that adjusts the excitation frequency of a transducer from an intelligent search done in a preloaded database. The information retrieved from the database acts on the feedback loop of an oscillator. The results showed that the system is agile, robust, simple building and the hardware is low cost, besides the fact of the magnitude of the errors, the values are around 0.02 kHz, should not severely affect the performance of the system.

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Análise de técnicas de economia de energia de estações rádio base baseadas em OpenBTS

Mateus de Oliveira e Mattos, Rafael da Silva Macedo, Mateus Carpanez Corrêa, Álvaro Augusto M. de Medeiros

DOI: 10.14209/sbrt.2017.43

Keywords: Green Cellular Networks Cell Zooming Sleep Mode OpenBTS.

Abstract

This article presents an analysis of base station power saving techniques in software defined radio platforms. This analysis is based on the USRP N210 platform and the OpenBTS software. The main objective of the article is to analyze, in a pratical way, the energy efficiency of methods cell zooming and sleep mode.

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Analise das propriedades dielétricas da matriz cerâmica de Al2O3 com a adição de TiO2 para aplicação como antena ressoadora dielétrica

Luiz Nonato Lopes de Oliveira, Raphael Victor Barros Campos, Marcelo Antônio Santos da Silva, Daniel Xavier Gouveia, Antônio Sergio Bezerra Sombra

DOI: 10.14209/sbrt.2017.44

Keywords: Antennas ceramics,return loss,radiation pattern.

Abstract

This paper aims to present the characteristics of an dielectric resonator antenna (DRA) made from alumina ceramic matrix (Al2O3) with the addition of titanium oxide (TiO2), the method used to improve the dielectric properties of the ceramic matrix favoring its use in microwave and RF circuits. After analyzing the results, it was confirmed the material as a good alternative for application in telecommunications as ARD, with gains around 3,76 dBi and 99,07% efficiency

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A Low-Cost Ultra-Wideband Test-Bed

Andrés Altieri, Pablo Gámez, Edgardo Marchi, Marcos Cervetto, Magdalena Bouza, Cecilia G. Galarza

DOI: 10.14209/sbrt.2017.46

Keywords: Wireless communications ultra-wideband test- bed

Abstract

This paper presents the design and implementation of a simple transceiver test-bed for implementing and testing algorithms for impulsive UWB applications. The platform has been developed using low-cost off-the-shelf components. We have conceived a simple modular architecture that was targeted to low power, short-range applications. The test-bed is discussed, commenting on the main design decisions and the benefits of the chosen architecture. Measurements of some blocks of the system are also presented.

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Nuclei Detection Using Deep Learning

Eliezer Farrant Braz, Roberto de Alencar Lotufo

DOI: 10.14209/sbrt.2017.48

Keywords: Nucleus detection Convolutional Neural Networks

Abstract

An important objective in the analysis of Pap smear images is automatic detection of a cell’s nucleus. Various methods that automatically detect the nuclei of cervical cells have been proposed to improve the analysis of screening test images. In this paper, we propose a Convolutional Neural Networksbased method that automatically detects the nuclei of cervical cells. Following training using a public dataset provided by the Overlapping Cervical Cytology Image Segmentation Challenge - ISBI 2014, the network’s fully connected layers are converted to convolutional layers to enable processing of images of any size. Our results were then compared with those achieved by other participants who successfully submitted their work to ISBI 2014 and other studies that used the same dataset. Our experimental results indicate that the methodology provides fast nuclei detection with precision and recall that are comparable with the state-of-the-art methods used to detect the nuclei of cervical cells.

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Environmental Effects on Short Dipole Antenna and RFID UHF Passive Tags

Wilson Costa Felix, Tcharllys Viana de Sousa, Raquel Aline Araújo Rodrigues, Felipe de Pádua A. Almeida

DOI: 10.14209/sbrt.2017.52

Keywords: short dipole antenna RFID tag performance materials temperature.

Abstract

The use of RFID systems as sensing and identification systems is increasing in the last years. Along the reduction of costs, the study of RFID technology needs more research about the effects of temperature, humidity, altitude, vibration and some materials on its readability and operability. The effects of temperature and some materials in the performance of short dipole antennas and RFID UHF passive tags are presented in this paper, using simulations and measurements. It has been found that all the materials affected the antenna’s performance. The effects of the temperature in the read range of five RFID UHF passive tags were measured with different temperatures and the relation between read range and temperature was verified.

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