VCO Banda Larga Integrado para Receptor a Cinco Portas

This work presents an wideband ring VCO for cognitive radio five-port based receivers. A three-stage differential topology using transmission gate was adopted in order to maintain wide and linear tuning range and a low phase-noise. Monte-Carlo analysis were performed for phase-shift response of individual stages, which is an important figure of merit in five-port works. It was observed a fairly linear correlation between control voltage and oscillation frequency in the range between 200 MHz and 1800 MHz. The VCO was preliminarily designed for IBM 130nm CMOS technology

Arranjos Log-Periódicos Compactos em Microfita com Elementos Fractais de Koch

This work aims to present how the application of fractal geometry to the elements of a log-periodic array can become a good alternative when one wants to reduce the size of the array. Two types of log-periodic arrays were proposed: one with fed by microstrip line and other fed by electromagnetic coupling. To the elements of these arrays were applied fractal Koch contours, at two levels. In order to validate the results obtained some prototypes were built, which were measured on a vector network analyzer and simulated in a software, for comparison. The results presented reductions of 60% in the total area of the arrays, for both types. By analyzing the graphs of return loss, it was observed that the application of fractal contours made different resonant frequencies appear in the arrays. Furthermore, a good agreement was observed between simulated and measured results. The array with feeding by electromagnetic coupling presented, after application of fractal contours, radiation pattern with more smooth forms than the array with feeding by microstrip line

Análise de onda completa de superfície seletiva em freqüência do tipo anteparo duplo

This work presents a theoretical analysis and numerical and experimental results of the scattering characteristics of frequency selective surfaces, using elements of type patch perfectly conductor. The structures are composed of two frequency selective surfaces on isotropic dielectric substrates cascaded, separated by a layer of air. The analysis is performed using the method of equivalent transmission line in combination with the Galerkin method, to determine the transmission and reflection characteristics of the structures analyzed. Specifically, the analysis uses the impedance method, which models the structure by an equivalent circuit, and applies the theory of transmission lines to determine the dyadic Green's function for the cascade structure. This function relates the incident field and surface current densities. These fields are determined algebraically by means of potential incidents and the imposition of the continuity of the fields in the dielectric interfaces. The Galerkin method is applied to the numerical determination of the unknown weight coefficients and hence the unknown densities of surface currents, which are expanded in terms of known basis functions multiplied by these weight coefficients. From the determination of these functions, it becomes possible to obtain numerical scattered fields at the top and bottom of the structures and characteristics of transmission and reflection of these structures. At work, we present numerical and experimental results for the characteristics of transmission and reflection. Comparisons were made with other results presented in literature, and it was observed a good agreement in the cases presented suggestions continuity of the work are presented

Desenvolvimento e testes de software de um receptor de GPS para uso espacial

Spacecraft move with high speeds and suffer abrupt changes in acceleration. So, an onboard GPS receiver could calculate navigation solutions if the Doppler effect is taken into consideration during the satellite signals acquisition and tracking. Thus, for the receiver subject to such dynamic cope these shifts in the frequency signal, resulting from this effect, it is imperative to adjust its acquisition bandwidth and increase its tracking loop to a higher order. This paper presents the changes in the GPS Orion s software, an open architecture receiver produced by GEC Plessey Semiconductors, nowadays Zarlink, in order to make it able to generate navigation fix for vehicle under high dynamics, especially Low Earth Orbit satellites. GPS Architect development system, sold by the same company, supported the modifications. Furthermore, it presents GPS Monitor Aerospace s characteristics, a computational tool developed for monitoring navigation fix calculated by the GPS receiver, through graphics. Although it was not possible to simulate the software modifications implemented in the receiver in high dynamics, it was observed that the receiver worked in stationary tests, verified also in the new interface. This work also presents the results of GPS Receiver for Aerospace Applications experiment, achieved with the receiver s participation in a suborbital mission, Operation Maracati 2, in December 2010, using a digital second order carrier tracking loop. Despite an incident moments before the launch have hindered the effective navigation of the receiver, it was observed that the experiment worked properly, acquiring new satellites and tracking them during the VSB-30 rocket flight.

Classificação Automática de Modulação Digital com uso de Correntropia para Ambientes de Rádio Cognitivo

Modern wireless systems employ adaptive techniques to provide high throughput while observing desired coverage, Quality of Service (QoS) and capacity. An alternative to further enhance data rate is to apply cognitive radio concepts, where a system is able to exploit unused spectrum on existing licensed bands by sensing the spectrum and opportunistically access unused portions. Techniques like Automatic Modulation Classification (AMC) could help or be vital for such scenarios. Usually, AMC implementations rely on some form of signal pre-processing, which may introduce a high computational cost or make assumptions about the received signal which may not hold (e.g. Gaussianity of noise). This work proposes a new method to perform AMC which uses a similarity measure from the Information Theoretic Learning (ITL) framework, known as correntropy coefficient. It is capable of extracting similarity measurements over a pair of random processes using higher order statistics, yielding in better similarity estimations than by using e.g. correlation coefficient. Experiments carried out by means of computer simulation show that the technique proposed in this paper presents a high rate success in classification of digital modulation, even in the presence of additive white gaussian noise (AWGN)

Estudo de Superfícies Seletivas de Frequência com o Uso de Inteligência Computacional

The main objective of this work is to optimize the performance of frequency selective surfaces (FSS) composed of crossed dipole conducting patches. The optimization process is performed by determining proper values for the width of the crossed dipoles and for the FSS array periodicity, while the length of the crossed dipoles is kept constant. Particularly, the objective is to determine values that provide wide bandwidth using a search algorithm with representation in bioinspired real numbers. Typically FSS structures composed of patch elements are used for band rejection filtering applications. The FSS structures primarily act like filters depending on the type of element chosen. The region of the electromagnetic spectrum chosen for this study is the one that goes from 7 GHz to 12 GHz, which includes mostly the X-band. This frequency band was chosen to allow the use of two X-band horn antennas, in the FSS measurement setup. The design of the FSS using the developed genetic algorithm allowed increasing the structure bandwidth

Análise comparativa de traduções do Cântico dos Cânticos

Observam-se especialmente as divergências entre as duas, no que diz respeito ao erotismo presente no poema, e analisando as suas prováveis razões discursivas. Não se visa aqui a produção de uma nova tradução, mas a comparação e o comentário das escolhas tradutórias em determinados excertos das obras selecionadas. A argumentação desenvolvese através dos seguintes encaminhamentos: após a apresentação do objeto de estudo com o debate que sempre o acompanha acerca das polêmicas de datação e autoria, passa-se à exposição do problema do qual se ocupa a hipótese, assim como os objetivos e os parâmetros metodológicos que regeram a elaboração desta dissertação. Consecutivamente, elencam-se os pressupostos teóricos que emolduram as análises propostas, aborda-se também a sexualidade segundo a religião contemporânea (por se tratar de um livro ao qual se agregou valor religioso) nas instituições que adotaram o Cântico dos Cânticos, a saber: o judaísmo e o cristianismo católico e protestante, assim como o processo possivelmente efetuado durante essa adoção quanto ao enviesamento interpretativo e à atribuição autoral: visa-se compreender as razões da incongruência causada pelo sexo que permeia o texto em questão relativamente à religiosidade contemporânea, e especula-se sobre a sua canonização, considerando como esse desencaixe pode ter mudado o curso da sua exegese tradicional para a alegoria que se tornou a sua leitura majoritária, inclusive engendrando a atribuição tradicional da sua suposta origem. Somente então se dá início à análise comparativa das duas traduções, a fim de se constatar a provável existência dum viés discursivo transparecente das formas como cada uma destas obras verteu as porções do texto-fonte, para o português, que continham marcas de erotismo, observando se respeitaram ou não as leituras tradicionais que insuflaram no texto o seu pendor alegórico de caráter religioso

A argumentação como elemento discursivo na mídia digital: um estudo sobre o blog fatos e dados

This thesis studies the use of argumentation as a discursive element in digital media, particularly blogs. We analyzed the Blog "Fatos e Dados" [Facts and Data], created by Petrobras in the context of allegations of corruption that culminated in the installation of a Parliamentary Commission of Inquiry to investigate the company within the Congress. We intend to understand the influence that the discursive elements triggered by argumentation exercise in blogs and about themes scheduling. To this end, we work with notions of argumentation in dialogue with questions of language and discourse from the work of Charaudeau (2006), Citelli (2007), Perelman & Olbrechts-Tyteca (2005), Foucault (2007, 2008a), Bakhtin (2006) and Breton (2003). We also observe our subject from the perspective of social representations, where we seek to clarify concepts such as public image and the use of representations as argumentative elements, considering the work of Moscovici (2007). We also consider reflections about hypertext and the context of cyberculture, with authors such as Levy (1993, 1999, 2003), Castells (2003) and Chartier (1999 and 2002), and issues of discourse analysis, especially in Orlandi (1988, 1989, 1996 and 2001), as well as Foucault (2008b). We analyzed 118 posts published in the first 30 days of existence of the blog "Fatos e Dados" (between 2 June and 1 July 2009), and analyzed in detail the top ten. A corporate blog aims to defend the points of view and public image of the organization, and, therefore, uses elements of social representations to build their arguments. It goes beyond the blog, as the main news criteria, including the posts we reviewed, the credibility of Petrobras as the source of information. In the posts analyzed, the news values of innovation and relevance also arise. The controversy between the Blog and the press resulted from an inadequacy and lack of preparation of media to deal with a corporate blog that was able to explore the characteristics of liberation of the emission pole in cyberculture. The Blog is a discursive manifestation in a concrete historical situation, whose understanding and attribution of meaning takes place from the social relations between subjects that, most of the time, place themselves in discursive and ideological dispute between each other - this dispute also affects the movements of reading and reading production. We conclude that intersubjective relationships that occur in blogs change, in the form of argumentative techniques used, the notions of news criteria, interfering with scheduling of news and organization of information in digital media outlets. It is also clear the influence that the discursive elements triggered by argumentation exercise in digital media, trying to resize and reframe frames of reality conveyed by it in relation to the subject-readers. Blogs have become part of the scenario information with the emergence of the Internet and are able to interfere in a more effective way to organize the scheduling of media from the conscious utilization of argumentative elements in their posts

Entre a fé, a obra social e a publicidade: uma análise crítica do discurso da responsabilidade social da Igreja Universal do Reino de Deus

Situated on Applied Linguistics (PENNYCOOK, 1998; MOITA LOPES, 2003, 2006, 2008, 2009), this thesis, which is inscribed in a qualitative-interpretative approach of a critical analysis perspective , lies on the speech of social responsibility and the way like that is employed in seeking for legitimacy and prestige within the neopentecostal brazilian religious field, more specifically of the Universal Church of the Kingdom of God. The general goal of this research is t reflect upon the speech on social responsibility and the rethoric of selfpromotion of the Universal Church through the role of social actors in the making of his her identities, materialized in the newspaper Folha Universal. In order to achieve that, we have conjugated, in this research, social and discursive analysis. On the linguistic-discursive approach, the research is based on the Critical Analysis of Discourse (ACD), specially in Fairclough (2001, 2003, 2006), a proposal that provides theoretical-methodological tools to investigate the language beyond the linguistic structures , that is, the discourse, social practices in which it occurs and more ample structures. Theoretical assumptions were also used of Sistemico-Functional Linguistics(LSF), matching with categories of the Transitivity System of Halliday (1994, 2004), of the forms of representation of social actors in the socioeconomic perspective by Van Leeuwen (1997, 2008) and of the Appraisal system by Martin and White (2005). As we develop the argumentation on thesobre social role of religion in this thesis, we make use of the authors such as Freston (1994), Oro (1997, 2003), Campos (1996, 1999), Mariano (1999), Meneses (2008), among several ones. We have also used a series of concepts and categories coming from the field of communication and marketing on the business social responsability and social marketing . In this area, we take as references the contributions of Bueno (2003), Fossá and Sartoretto (2003) and Zenone (2006). The corpus of the work is framed by news taken at the newspaper Folha Universal, in which are given the social responsibility actions of the church . The timeframe used was on the editions of 2010 thru 2012. Results found at he analysis of the News lead to semantic features of Assessment of Affection, Judgment and Appreciation, many times followed by Gradation, and the Attribution, one of the subsystems of the Attachment, are evidence of positive assessments for the Universal Church and its agents and make up rethorical elements which provide structure for the discourse of the Universal Church at the newspaper Folha Universal consisted of its image (style) of social responsibility . Results show that the most frequente social actors of the discourse are, on one hand, the Universal Church itself and its volunteers, famous (actors, actresses, presenters), politicians and authorities, on the other hand, the population which was helped by the Church social projects . The first group seems to be Always activated, however the second one, most of the time rather passive. These are also represented by assimilation in most of the occurrences, however the other ones by individualization and nomination entitled by honorification, except for the volunteers that are represented either as an individual, or as a group

A relação entre as noções de eleuthería e autárkeia na filosofia de Epicuro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Filtros acústicos em cristais fonônicos

In this work, we have studied the acoustic phonon wave propagation within the periodic and quasiperiodic superlattices of Fibonacci type. These structures are formed by phononic crystals, whose periodicity allows the raise of regions known as stop bands, which prevent the phonon propagation throughout the structure for specific frequency values. This phenomenon allows the construction of acoustic filters with great technological potential. Our theoretical model were based on the method of the transfer matrix, thery acoustics phonons which describes the propagation of the transverse and longitudinal modes within a unit cell, linking them with the precedent cell in the multilayer structure. The transfer matrix is built taking into account the elastic and electromagnetic boundary conditions in the superllatice interfaces, and it is related to the coupled differential equation solutions (elastic and electromagnetic) that describe each model under consideration. We investigated the piezoelectric properties of GaN and AlN the nitride semiconductors, whose properties are important to applications in the semiconductor device industry. The calculations that characterize the piezoelectric system, depend strongly on the cubic (zinc-bend) and hexagonal (wurtzite) crystal symmetries, that are described the elastic and piezoelectric tensors. The investigation of the liquid Hg (mercury), Ga (gallium) and Ar (argon) systems in static conditions also using the classical theory of elasticity. Together with the Euler s equation of fluid mechanics they one solved to the solid/liquid and the liquid/liquid interfaces to obtain and discuss several interesting physical results. In particular, the acoustical filters obtained from these structures are again presented and their features discussed

Ondas de spin em nanofilmes nagnéticos acoplados quasiperiodicamente

We studied the spin waves modes that can propagate in magnetic multilayers composed of ferromagnetic metallic films in the nanometer scale. The ferromagnetic films (iron) are separated and coupled through the nonmagnetic spacer films (chromium). The films that make up the multilayer are stacked in a quasiperiodic pattern, following the Fibonacci and double period sequences. We used a phenomenological theory taking into account: the Zeeman energy (between the ferromagnetic films and the external magnetic field), the energy of the magneto-crystalline anisotropy (present in the ferromagnetic films), the energy of the bilinear and biquadratic couplings (between the ferromagnetic films) and the energy of the dipole-dipole interaction (between the ferromagnetic films), to describe the system. The total magnetic energy of the system is numerically minimized and the equilibrium angles of the magnetization of each ferromagnetic film are determined. We solved the equation of motion of the multilayer to find the dispersion relation for the system and, as a consequence, the spin waves modes frequencies. Our theoretical results show that, in the case of trilayers (Fe/Cr/Fe), our model reproduces with excellent agreement experimental results of Brillouin light scattering, known from the literature, by adjusting the physical parameters of the nanofilms. Furthermore, we generalize the model to N ferromagnetic layers which allowed us to determine how complex these systems become when we increase the number of components. It is worth noting that our theoretical calculations generalize all the results known from the literature

Efeitos da eletroestimulação sobre os parâmetros eletromiográficos e dinamométricos do músculo quadríceps femoral

To analyze the effects of electrical stimulation at two frequencies on the EMG parameters (EMG) and dynamometer, in muscles with different typing. MATERIALS AND METHODS: This is a controlled clinical trial, randomized and double blind. Sixty healthy volunteers (23.6 ± 4.2anos; 54.2 ± 7.7kg, 1.62 ± 0.009 cm) of both sexes were divided randomly into three groups: control group (CG), experimental group 1 (SG1) with application of the current Russian 30 HZ and experimental group 2 (EG2) at 70 Hz The volunteers performed an initial assessment (AV1) on the isokinetic dynamometer with three repetitions maximum voluntary isometric (MVC) for knee extension concomitant uptake of EMG for the VM muscle, VL and RF. Later, after application of NMES, they underwent an experimental protocol of isometric fatigue using 70% of MVIC, ending with the completion of a final assessment (AV2) in the same manner as the AV1. RESULTS: By analyzing the profile of the 60 subjects in three broad, VM showed a higher value of RMS behavior when the VL and RF (p = 0.03 and p = 0.02). With respect to Fmed the RF muscle (p = 0.001) showed a higher value for the VM. The VM muscle showed significant increases of Fmed (p = 0.05) after electrical stimulation at 70 Hz when compared the AV1 AV2 and RF showed significant decreases (p = 0.009) after stimulation at 30 Hz during the fatigue showed an increase RMS in the VM and VL, with a reduction in RF. For the variable Fmed was observed in three broad decline during fatigue. CONCLUSION: Our findings provide evidence that the muscles VM, VL and RF fiber typing are different besides indicating that the frequency of NMES tend to relate to the muscle stimulated. Finally suggests the surface EMG as a noninvasive method for characterizing muscle

Estágio menopausal e níveis hormonais no desenvolvimento muscular e funcional em mulheres de meia idade: um estudo transversal

Introduction: Hypoestrogenism is the main characteristic of female aging. It promotes significant changes in body composition, both in fat mass as in lean body mass, leading to a decrease in muscle strength and physical performance. Objective: The aim of this study was to test whether menopausal status and hormone levels are associated with muscular strength and physical performance in middle-aged women. Methods: In a cross-sectional study it was collected sociodemographic data, gynecological history, anthropometric and biochemical measures in women aged 40 to 65 years in Parnamirim-RN. The menopause status (pre, peri and post menopause) was determined by menstrual history. All women underwent three dimensions of physical performance assessment: handgrip dynamometry, gait speed and chair stands test - Short Physical Performance Battery (SPPB). Categorical data were presented as absolute and relative frequencies. Quantitative data were showed as mean and standard deviation and the normality of distribution was verified with Kolmogorov-Smirnov (KS) test. Biochemical measures of estradiol and follicle-stimulating hormone (FSH) were transformed to log10. ANOVA with Tukey post-test for comparison of variables between the groups pre, peri and post-menopausal was performed and then multiple linear regression analyzes. Results: Two hundred and seventy eight women aged 50.2 (±5.58) years composed this study, being 50 women in premenopausal status (18%), 122 in perimenopausal (43.9%), and 106 postmenopausal stage (38.1%). The groups were different in age (p=0.001), marital relationship duration (p <0.001), number of pregnancies (p=0.001) and parity (p=0.001). Differences in biochemical measures were observed among the groups: estradiol (p<0.001), FSH (p<0.001), total cholesterol (p=0.001). There were no differences in gait velocity between menopausal status. Values in mean of grip strength decreased by postmenopausal women to perimenopausal and premenopausal ones (24.5 ± 5.1, 25.6 ± 5.4, 26.9 ± 4.9 for post-stage, pre and peri menopausas, respectively, p = 0.02) and the performance of chair stands test was better in premenopausal women compared with that in peri and postmenopausal status (p = 0.02). In multiple linear regression for muscle strength, the variables that remained were: age, estradiol and somatic symptoms measured by Menopause Rating Scale-MRS (R2=0.15). While for the xiv chair-stands test the predictors were number of births and FSH values (R2=0.04). Conclusion: There is a relationship between the stages of menopause and muscle performance in measures of grip strength and sit-up test and these are influenced by the fall of estrogens levels. Data suggest that the decrease in muscle strength and physical performance already appear in the transition to menopause stage, pointing to the need for more research in this area and appropriate preventive interventions

Caracterização dos acoplamentos fase-amplitude na região CA1 do hopocampo

Brain oscillation are not completely independent, but able to interact with each other through cross-frequency coupling (CFC) in at least four different ways: power-to-power, phase-to-phase, phase-to-frequency and phase-to-power. Recent evidence suggests that not only the rhythms per se, but also their interactions are involved in the execution of cognitive tasks, mainly those requiring selective attention, information flow and memory consolidation. It was recently proposed that fast gamma oscillations (60 150 Hz) convey spatial information from the medial entorhinal cortex to the CA1 region of the hippocampus by means of theta (4-12 Hz) phase coupling. Despite these findings, however, little is known about general characteristics of CFCs in several brain regions. In this work we recorded local field potentials using multielectrode arrays aimed at the CA1 region of the dorsal hippocampus for chronic recording. Cross-frequency coupling was evaluated by using comodulogram analysis, a CFC tool recently developted (Tort et al. 2008, Tort et al. 2010). All data analyses were performed using MATLAB (MathWorks Inc). Here we describe two functionally distinct oscillations within the fast gamma frequency range, both coupled to the theta rhythm during active exploration and REM sleep: an oscillation with peak activity at ~80 Hz, and a faster oscillation centered at ~140 Hz. The two oscillations are differentially modulated by the phase of theta depending on the CA1 layer; theta-80 Hz coupling is strongest at stratum lacunosum-moleculare, while theta-140 Hz coupling is strongest at stratum oriens-alveus. This laminar profile suggests that the ~80 Hz oscillation originates from entorhinal cortex inputs to deeper CA1 layers, while the ~140 Hz oscillation reflects CA1 activity in superficial layers. We further show that the ~140 Hz oscillation differs from sharp-wave associated ripple oscillations in several key characteristics. Our results demonstrate the existence of novel theta-associated high-frequency oscillations, and suggest a redefinition of fast gamma oscillations