Energy efficient scheme based on simultaneous transmission of the local decisions in cooperative spectrum sensing

A common concern regarding cooperative spectrum sensing (CSS) schemes is the occupied bandwidth and the energy consumption during the transmissions of sensing information to the fusion center over the reporting control channels. This concern is intensified if the number of cooperating secondary users in the network is large. This article presents a new fusion strategy for a CSS scheme, aiming at increasing the energy efficiency of a recently proposed bandwidth-efficient fusion scheme. Analytical results and computational simulations unveil a high increase in energy efficiency when compared with the original approach, yet achieving better performances in some situations, and lower implementation complexity

Improved decision for a resource-efficient fusion scheme in cooperative spectrum sensing

Paper presented at at 2015 International Workshop on Telecommunications (IWT), 14th to 17th of June, Santa Rita do Sapucai, Brazil. Abstract Recently, a novel decision fusion scheme for cooperative spectrum sensing was proposed, aiming at saving resources in the reporting channel transmissions. Secondary users are allowed to report their local decisions through the symbols of binary modulations, at the same time and with the same carrier frequencies. As a consequence, the transmitted symbols add incoherently at the fusion center, forming a larger set of symbols in which a subset is associated to the presence of the primary signal, and another subset is associated to the absence of such a signal. A Bayesian decision criterion with uniform prior was applied for discriminating these subsets. In this paper we propose a modified decision rule in which the target probabilities of detection and false alarm are taken into account to produce a large performance improvement over the original decision criterion. This improvement comes with practically no cost in complexity and does not demand the knowledge of any additional information when compared to the original rule

Resource-efficient fusion with pre-compensated transmissions for cooperative spectrum sensing

© 2015 by the authors; licensee MDPI, Basel, Switzerland. Recently, a novel fusion scheme for cooperative spectrum sensing was proposed for saving resources in the control channel. Secondary users (SUs) simultaneously report their decisions using binary modulations with the same carrier frequencies. The transmitted symbols add incoherently at the fusion centre (FC), leading to a larger set of symbols in which a subset is associated with the presence of the primary user (PU) signal, and another subset is associated with the absence of such a signal. The decision criterion applied for discriminating these subsets works under the assumption that the channel gains are known at the FC. In this paper, we propose a new simultaneous transmission and decision scheme in which the task of channel estimation is shifted from the FC to the SUs, without the need for feeding-back of the estimates to the FC. The estimates are used at the SUs to pre-compensate for the reporting channel phase rotations and to partially compensate for the channel gains. This partial compensation is the result of signal clipping for peak-to-average power ratio (PAPR) control. We show, analytically and with simulations, that this new scheme can produce large performance improvements, yet reduces the implementation complexity when compared with the original one

Sistema de análise vibracional preditiva para usinagem / Predictive vibration analysis system for machining

O sensoriamento é de notória importância para o funcionamento da indústria 4.0 em busca de melhorias contínuas nos processos produtivos. Durante a manufatura, a manutenção corretiva é um problema evitável com a manutenção preventiva, porém com a 4ª revolução industrial a maneira de planejar e realizar manutenção progrediu. Nesse intento propôs-se  o desenvolvimento de um sistema de análise vibracional para auxiliar na manutenção preditiva, por meio da utilização de um sensor acelerômetro que fornecerá informações pertinentes para o planejamento estratégico da empresa.

COMPORTAMENTO POPULACIONAL NA EVACUAÇÃO EM MASSA

Um dos principais processos na resposta a desastres é a evacuação em massa da população afetada. Considerando a resposta ao vazamento da usina nuclear de Chernobyl, ao furacão Katrina, ao vazamento na usina nuclear de Fukushima após o tsunami no Japão em 2011, e ao rompimento da barragem em Mariana, este artigo visa comparar o processo de evacuação em massa nestes desastres, evidenciando problemas e contextos a serem considerados por profissionais que atuam nas etapas de alarme, retirada, abrigo e retorno da população afetada

Design, Prototyping and Stratospheric Launch of CubeSats for University Competition

This work presents the design and prototyping of two 1U standard CubeSats for the First Brazilian MCTI Satellite Olympiad, launching one in a stratospheric helium-filled balloon. The nanosatellites were designed for two missions: Internet of Things connectivity in remote areas based on CubeSat (IoSat) and low-orbit harmful gamma radiation mapping (LOHGRM). The IoSat mission aimed to provide server connectivity for a remote sensor network. The LOHGRM CubeSat was designed for sensing and mapping gamma radiation power levels in the satellite’s orbit to construct a heat map to study the gamma radiation effect on the equipment. The prototype’s performance was evaluated based on physical, mechanical, magnetic, thermal, and transmission characterization, with satisfactory results under test conditions. The LOHGRM mission test was carried out on the ground as proof of concept without flying while a stratospheric balloon launched the IoSat prototype. Due to restrictions imposed by the competition, the IoSat nanosatellite only captured and registered altitude, pressure, and temperature data without testing the communication payload. Instead, this data was sent to the ground station through the competition communication system and stored in a memory card to assess its operation during the flying. The satellite’s maximum altitude was 22.6 km, operating under –23.5 °C

Sistema para controle de acesso à universidade utilizando NFC e QR Code / University access control system using NFC and QR Code

A tecnologia está sendo incorporada aos objetos de forma invisível, se tornando cada vez mais imperceptível aos olhos humanos e mais útil na rotina das pessoas, principalmente na maneira como se relacionam entre si e com o meio. Entre as tecnologias presentes nesse cenário, destacam-se o NFC (Near Field Communication – Comunicação de Campo Próximo) e o QR Code (Quick Response Code – Código de Resposta Rápida), pois permitem inúmeras aplicações, por exemplo: pagamentos móveis, acesso a conteúdos digitais, consumo de entretenimento, passaportes eletrônicos, ingressos para eventos, pedágios, transporte, atividades esportivas, entre outros. Nesse trabalho, reportou-se uma proposta alternativa para um sistema de identificação de usuários e de controle de acesso de pessoas à universidade. O acesso ao sistema pode ser através de duas opções: QR Code ou NFC. O projeto foi desenvolvido com o microcontrolador Arduino e a programação por linguagem C com auxílio do ambiente de desenvolvimento integrado IDE (Integrated Development Environment) Arduino

DISTÚRBIO HIPERTENSIVO GESTACIONAL: UMA GRAVIDEZ DE ALTO RISCO

Arterial hypertension is responsible for almost 20% of maternal deaths in Brazil. It is considered and classified by the Ministry of Health as “at risk” when installed during pregnancy. During this period, it poses a risk not only to the mother, but also to the fetus. For this reason, this disorder requires early and effective prevention, diagnosis and treatment initiatives to avoid both maternal and fetal complications. Its investigation begins with the first prenatal consultation, assessing risk factors for not only gestational hypertension, but also for its complications, such as pre-eclampsia and eclampsia. The following work aims to unravel and classify hypertensive disorders during the gestational period.La hipertensión arterial es responsable de casi el 20% de las muertes maternas en Brasil. Es considerado y clasificado por el Ministerio de Salud como “de riesgo” cuando se instala durante el embarazo. Durante este período, representa un riesgo no solo para la madre, sino también para el feto. Por esta razón, este trastorno requiere iniciativas de prevención, diagnóstico y tratamiento tempranos y efectivos para evitar complicaciones tanto maternas como fetales. Su investigación comienza con la primera consulta prenatal, evaluando los factores de riesgo no solo de la hipertensión gestacional, sino también de sus complicaciones, como la preeclampsia y la eclampsia. El siguiente trabajo tiene como objetivo desentrañar y clasificar los trastornos hipertensivos durante el período gestacional.A hipertensão arterial é responsável por quase 20% das mortes maternas no Brasil. É considerada e classificada pelo Ministério da Saúde “de risco” quando instalada durante a gestação. Nesse período, apresenta risco não só para a mãe, mas também para o feto. Por esse motivo, esse distúrbio exige iniciativas de prevenção, diagnóstico e tratamentos precoces e efetivos para evitar complicações tanto maternas quanto fetais. Sua investigação é dada desde a primeira consulta pré-natal, sendo avaliados fatores de risco para não só a hipertensão gestacional, mas também para suas complicações, como a pré-eclâmpsia e a eclampsia. O seguinte trabalho tem como objetivo destrinchar e classificar os distúrbios hipertensivos durante o período gestacional. A hipertensão arterial é responsável por quase 20% das mortes maternas no Brasil. É considerada e classificada pelo Ministério da Saúde “de risco” quando instalada durante a gestação. Nesse período, apresenta risco não só para a mãe, mas também para o feto. Por esse motivo, esse distúrbio exige iniciativas de prevenção, diagnóstico e tratamentos precoces e efetivos para evitar complicações tanto maternas quanto fetais. Sua investigação é dada desde a primeira consulta pré-natal, sendo avaliados fatores de risco para não só a hipertensão gestacional, mas também para suas complicações, como a pré-eclâmpsia e a eclampsia. O seguinte trabalho tem como objetivo destrinchar e classificar os distúrbios hipertensivos durante o período gestacional.&nbsp

[Covid-19 in the Northeast of Brazil: from lockdown to the relaxation of social distancing measures].

Even in the period when the Covid-19 pandemic was on the rise in the Northeast of Brazil, the relaxation of social distancing measures was introduced. The scope of the study is to assess, in the light of the epidemiological-sanitary situation in the region, the suitability of relaxation of social distancing measures. Based on the WHO guidelines for relaxation of social distancing, operational indicators were created and analyzed for each guideline in the context of the Northeast. To analyze the behavior of the epidemic, according to selected indicators, Joinpoint trend analysis techniques, heat maps, rate ratios and time trends between capitals and the state interior were compared. The weekly growth peak of the epidemic occurred in May-July 2020 (epidemiological weeks 19 to 31). In most capitals, there was no simultaneous downward trend in the number of cases and deaths in the 14 days prior to flexibilization. In all states the number of tests performed was insufficient. In epidemiological week 24, the state percentages of ICU/Covid-19 bed occupancy were close to or above 70%. The epidemiological situation of the nine Northeastern state capitals analyzed here did not meet criteria and parameters recommended by the World Health Organization for the relaxation of social distancing measures