Characterization of systems for software defined radio

Mestrado em Engenharia Electrónica e TelecomunicaçõesEsta dissertação insere-se na área de electrónica de rádio frequência, mais precisamente na caracterização de sistemas para rádios definidos por software (SDR). Um SDR é aquele que possui a flexibilidade para sintonizar, filtrar, ajustar a taxa de transmissão e controlar o tipo de modulação através de software. O aparecimento de novas tecnologias no mercado obriga à utilização de uma quantidade considerável de hardware nos dispositivos de transmissão/recepção, assim uma solução consiste no uso de arquitecturas de SDR onde a conversão do sinal analógico para digital é executada o mais próximo possível da antena e, sendo depois todo o processamento efectuado digitalmente. Assim, nesta tese, é apresentado um modelo comportamental para receptores de SDR, que leva em conta os elementos chave da distorção não linear. Além disso, são apresentadas algumas comparações entre simulações e medidas usando sinais multi-seno e WiMax usando um receptor ideal de SDR. Finalmente, é proposto um novo sistema de caracterização para dispositivos de SDR. ABSTRACT: This dissertation is related to the radio frequency area, more specifically to the characterization of systems for software-defined radio. A software-defined radio is one that has the flexibility to tune, filter, set the transmission rate and control the modulation type only by software. The emergence of new technologies in the market forces the use of a considerable quantity of hardware in the transceivers systems, so a viable solution for this is to use SDR solutions where the analogue to digital conversion is made closest possible of the antenna and then make all the processing digitally. So, in this dissertation, a behavioral model for SDR front end receiver evaluation, that captures the key elements of the nonlinear distortion, is proposed. Moreover, some comparisons between measured and simulated results under multisine and WiMax excitations are presented using the ideal SDR receiver. Finally, a new instrumentation system for characterization of SDR front ends is proposed

Characterization and modelling of software defined radio front-ends

Doutoramento em Engenharia ElectrotécnicaO presente trabalho tem por objectivo estudar a caracterização e modelação de arquitecturas de rádio frequência para aplicações em rádios definidos por software e rádios cognitivos. O constante aparecimento no mercado de novos padrões e tecnologias para comunicações sem fios têm levantado algumas limitações à implementação de transceptores rádio de banda larga. Para além disso, o uso de sistemas reconfiguráveis e adaptáveis baseados no conceito de rádio definido por software e rádio cognitivo assegurará a evolução para a próxima geração de comunicações sem fios. A ideia base desta tese passa por resolver alguns problemas em aberto e propor avanços relevantes, tirando para isso partido das capacidades providenciadas pelos processadores digitais de sinal de forma a melhorar o desempenho global dos sistemas propostos. Inicialmente, serão abordadas várias estratégias para a implementação e projecto de transceptores rádio, concentrando-se sempre na aplicabilidade específica a sistemas de rádio definido por software e rádio cognitivo. Serão também discutidas soluções actuais de instrumentação capaz de caracterizar um dispositivo que opere simultaneamente nos domínios analógico e digital, bem como, os próximos passos nesta área de caracterização e modelação. Além disso, iremos apresentar novos formatos de modelos comportamentais construídos especificamente para a descrição e caracterização não-linear de receptores de amostragem passa-banda, bem como, para sistemas nãolineares que utilizem sinais multi-portadora. Será apresentada uma nova arquitectura suportada na avaliação estatística dos sinais rádio que permite aumentar a gama dinâmica do receptor em situações de multi-portadora. Da mesma forma, será apresentada uma técnica de maximização da largura de banda de recepção baseada na utilização do receptor de amostragem passa-banda no formato complexo. Finalmente, importa referir que todas as arquitecturas propostas serão acompanhadas por uma introdução teórica e simulações, sempre que possível, sendo após isto validadas experimentalmente por protótipos laboratoriais.This work investigates the characterization and modeling of radio frequency front-ends for software defined radio and cognitive radio applications. The emergence of new standards and technologies in the wireless communications market are raising several issues to the implementation of wideband transceiver systems. Also, reconfigurable and adaptable systems based on software defined and cognitive radio models are paving the way for the next generation of wireless systems. In this doctoral thesis the fundamental idea is to address the particular open issues and propose appropriate advancements by exploring and taking profit from new capabilities of digital signal processors in a way to improve the overall performance of the novel schemes. Receiver and transmitter strategies for radio communications are summarized by concentrating on the usability for software defined radio and cognitive radio systems. Available instrumentation and next steps for analog and digital radio frequency hardware characterization is also discussed. Wideband behavioral model formats are proposed for nonlinear description and characterization of bandpass sampling receivers, as well as, for multi-carrier nonlinear systems operation. The proposed models share a great flexibility and have the freedom to be simply expanded to other fields. A new design for receiver dynamic range improvement in multi-carrier scenarios is proposed, which is supported on the useful wireless signals statistical evaluation. Additionally, receiver-side bandwidth maximization based on higher-order bandpass sampling approaches is evaluated. All the proposed designs and modeling strategies are accompanied by theoretical backgrounds and simulations whenever possible, being then experimentally validated by laboratory prototypes

Quality control and monitoring of NSM CFRP systems: E-modulus evolution of epoxy adhesive and its relation to the pull-out force

The present paper describes the application of an innovative technique (termed EMM-ARM: Elasticity Modulus Monitoring through Ambient Response Method) for continuous monitoring of the stiffening process of an epoxy adhesive used in near-surface mounted (NSM) fibre reinforced polymer (FRP) reinforcements. A simultaneous study of direct pull-out tests with concrete specimens strengthened with NSM carbon FRP laminate strips was carried out to compare the evolution of bond performance with the E-modulus of epoxy since early ages. A relationship between the evolution of epoxy E-modulus and the maximum pull-out force is assessed, highlighting the potential of applying EMM-ARM for quality control and decision-making assistance of NSM systems.This work is supported by FEDER funds through the Operational Program for Competitiveness Factors - COMPETE and National Funds through FCT - Portuguese Foundation for Science and Technology under the projects CutInDur PTDC/ECM/112396/2009 and VisCoDyn EXPL/ECM-EST/1323/2013. The authors also like to thank all the companies that have been involved supporting and contributing for the development of this study, mainly: S&P Clever Reinforcement Iberica Lda., Artecanter - Industria de Transformacao de Granitos, Lda., Vialam - Industrias Metalurgicas e Metalomecanicas, Lda. The first and second authors also acknowledge the grants SFRH/BD/80338/2011 and SFRH/BD/80682/2011, respectively, provided by FCT

Effects of curing temperature on pull-out behavior and stiffness evolution of epoxy adhesives for NSM-FRP applications

The efficiency of the FRP-concrete strengthening system is strongly influenced by the mechanical properties of the epoxy adhesive, which depend on the curing temperature.In the present work, the influence of temperature on the curing process of the epoxy was examined. Two different temperatures were studied: 20 and 30 °C. The elastic modulus of the adhesive was continuously monitored by using a variant of the classical resonant frequency methods, called EMM-ARM (Elasticity Modulus Monitoring through Ambient Response Method). A simultaneous study of direct pull-out tests with concrete specimens strengthened with NSM carbon FRP laminate strips was carried out at the same two different temperatures to compare the evolution of bond performance with the E-modulus of epoxy since early ages. The results showed that increasing the curing temperature significantly accelerated both the curing process of the epoxy adhesive and the evolution of bond performance. Moreover, the EMM-ARM technique revealed its ability in clearly identifying the hardening kinetics of epoxy adhesives, allowing measurements since very early ages and in different environmental conditions

Monitoring the early stiffness development in epoxy adhesives for structural strengthening

The present work aimed to assess the early-age evolution of E-modulus of epoxy adhesives used for Fibre-Reinforced Polymer (FRP) strengthening applications. The study involved adapting an existing technique devised for continuous monitoring of concrete stiffness since casting, called EMM-ARM (Elasticity Modulus Monitoring through Ambient Response Method) for evaluation of epoxy stiffness. Furthermore, monotonic tensile tests according to ISO standards and cyclic tensile tests were carried out at several ages. A comparison between the obtained results was performed in order to better understand the performance of the several techniques in the assessment of stiffness of epoxy resins. When compared to the other methodologies, the method for calculation of E-modulus recommended by ISO standard led to lower values, since in the considered strain interval, the adhesive had a non-linear stress-strain relationship. The EMM-ARM technique revealed its capability in clearly identifying the hardening kinetics of epoxy adhesives, measuring the material stiffness growth during the entire curing period. At very early ages the values of Young's modulus obtained with quasi-static tests were lower than the values collected by EMM-ARM, due to the fact that epoxy resin exhibited a significant visco-elastic behaviour.FEDER funds through the Operational Program for Competitiveness Factors – COMPETE and National Funds through FCT – Foundation for Science and Technology under the projects CutInDur PTDC/ECM/112396/2009 and VisCoDyn EXPL/ECM-EST/1323/2013. The authors also like to thank all the companies that have been involved supporting and contributing for the development of this study, mainly, S&P Clever Reinforcement Ibérica Lda. and Vialam – Indústrias Metalúrgicas e Metalomecânicas, Lda

Influence of temperature on the curing of an epoxy adhesive and its influence on bond behaviour of NSM-CFRP systems

In NSM-CFRP installations, the mechanical behaviour of the strengthening system is strongly influenced by the epoxy adhesive, particularly at early ages. In the present work, the influence of temperature on the curing process of the epoxy was investigated. Three distinct temperatures were studied: 20, 30 and 40 °C. The elastic modulus of the adhesive was monitored through EMM-ARM (Elasticity Modulus Monitoring through Ambient Response Method). Direct pull-out tests with concrete specimens strengthened with NSM CFRP strips were carried out at the same three distinct temperatures to compare the evolution of bond performance with the E-modulus of epoxy since early ages. The results showed that increasing the curing temperature significantly accelerated both the curing process of the epoxy adhesive and the evolution of bond performance. The EMM-ARM technique has revealed its ability in clearly identifying the hardening kinetics of epoxy adhesives, allowing also thermal activation analysis. Finally, existing models for predicting temperature-dependent mechanical properties were extended to also describe the bond behaviour of NSM-CFRP applications.This work is supported by FEDER funds through the Operational Program for Competitiveness Factors - COMPETE and National Funds through FCT - Portuguese Foundation for Science and Technology under the projects FRPreDur FCOMP-01-0124-FEDER-028865 (FCT no. PTDC/ECM-EST/2424/2012) and VisCoDyn FCOMP-01-0124-FEDER-041751 (FCT no. EXPL/ECM- EST/1323/2013). The authors also like to thank all the companies that have been involved supporting and contributing for the development of this study, mainly: S&P Clever Reinforcement Ibérica Lda., Artecanter - Indústria de Transformação de Granitos, Lda., Vialam – Indústrias Metalúrgicas e Metalomecânicas, Lda. The second and third authors also acknowledge the grants SFRH/BD/80338/2011 and SFRH/BD/80682/2011, respectively, provided by FCT

Bond on NSM CFRP systems: recent contributions of UMinho on durability, quality control and design

In the last years, significant research in the context of bond of near-surface mounted (NSM) fibre reinforced polymer (FRP) systems in concrete has been conducted at the Department of Civil Engineering of the University of Minho. This paper presents a brief summary of the major results obtained in that research, namely in terms of durability, quality control and design topics. Accelerated ageing tests on NSM FRP bond specimens were conducted to simulate different environmental conditions. A new method was developed and applied to investigate the evolution of the adhesive stiffness and the bond behaviour of NSM systems for different curing conditions used for quality control of FRP installations. Regarding the bond design, two existing guidelines’ formulas were adapted to the partial safety factors framework.This work was supported by FEDER funds through the Operational Program for Competitiveness Factors – COMPETE and National Funds through FCT (Portuguese Foundation for Science and Technology) under the projects CutInDur FCOMP-01-0124-FEDER-014811 (FCT PTDC/ECM/112396/2009), FRPreDur FCOMP-01- 0124-FEDER-028865 (FCT PTDC/ECM-EST/2424/2012), FRPLongDur POCI-01-0145-FEDER-016900 (FCT PTDC/ECM-EST/1282/2014) and partly financed by the project POCI-01-0145-FEDER-007633. The following individual grants are also acknowledged: SFRH/BD/80338/2011 (P. Fernandes), SFRH/BD/87443/2012 (M. Coelho), SFRH/BD/89768/2012 (P. Silva) and SFRH/BD/80682/2011 (J. Granja)

revista de Ciências da Arte

Ao lançarmos a chamada para o dossier de número 10 e 11 da Revista Convocarte, era esperado que a escolha temática, o encontro entre arte e loucura, traria uma grande variedade de considerações, nem sempre concordantes e, por vezes, surpreendentes. Por qualificar de “loucura” e não de “doença” e nem de outra coisa qualquer, avaliamos a oportunidade de escutar os diversos entendimentos que, em nossa sociedade, é possível fazer deste termo. É por isso que, no texto que lançava a chamada, propusemos: “tratar as questões da arte na loucura ou da loucura na arte implica uma série de contextualizações e temporalidades que, de antemão, qualificam tanto a obra quanto o sujeito que a produz”. Isto quer dizer que ao falarmos em loucura, ao revermos as suas bases psicológicas, as suas narrativas sociais, os panoramas médicos ou os apelativos artísticos, nós colaboramos em inventar a própria noção de loucura. A loucura não é um estado definido (ou definitivo) e atestado em laudo médico, ela é possibilitada nas relações entre a razão e a desrazão, ponderada pelo desejo de instituir amarras ou potências sobre os sujeitos que habitam este mundo. É e sempre será incitante perceber as variadas formas de produção dos sentidos da loucura. E quando possibilitamos narrativas que levam estes diversos sentidos ao encontro da arte, ou vice-versa, abrimos um sem fim de perspectivas sobre o que pode parecer ilógico ou imponderável: as expressões da loucura.info:eu-repo/semantics/publishedVersio

COVID-19 Severity and Survival over Time in Patients with Hematologic Malignancies: A Population-Based Registry Study

Mortality rates for COVID-19 have declined over time in the general population, but data in patients with hematologic malignancies are contradictory. We identified independent prognostic factors for COVID-19 severity and survival in unvaccinated patients with hematologic malignancies, compared mortality rates over time and versus non-cancer inpatients, and investigated post COVID-19 condition. Data were analyzed from 1166 consecutive, eligible patients with hematologic malignancies from the population-based HEMATO-MADRID registry, Spain, with COVID-19 prior to vaccination roll-out, stratified into early (February–June 2020; n = 769 (66%)) and later (July 2020–February 2021; n = 397 (34%)) cohorts. Propensity-score matched non-cancer patients were identified from the SEMI-COVID registry. A lower proportion of patients were hospitalized in the later waves (54.2%) compared to the earlier (88.6%), OR 0.15, 95%CI 0.11–0.20. The proportion of hospitalized patients admitted to the ICU was higher in the later cohort (103/215, 47.9%) compared with the early cohort (170/681, 25.0%, 2.77; 2.01–3.82). The reduced 30-day mortality between early and later cohorts of non-cancer inpatients (29.6% vs. 12.6%, OR 0.34; 0.22–0.53) was not paralleled in inpatients with hematologic malignancies (32.3% vs. 34.8%, OR 1.12; 0.81–1.5). Among evaluable patients, 27.3% had post COVID-19 condition. These findings will help inform evidence-based preventive and therapeutic strategies for patients with hematologic malignancies and COVID-19 diagnosis.Depto. de MedicinaFac. de MedicinaTRUEFundación Madrileña de Hematología y HemoterapiaFundación Leucemia y LinfomaAsociación Madrileña de Hematología y Hemoterapiapu

Drug-induced anaphylaxis, elicitors, risk factors, and management in Latin America

Nonsteroidal anti-inflammatory drugs were the most frequent triggers of drug-induced anaphylaxis in Latín America, whereas antibiotics elicited faster onset and more scvere reactions. An improvement was observed in epinephrinc use and adherence to guidelines in the emergency department treatment of anaphylaxis in Latín America compared with our last report.Facultad de Ciencias Médica