Desenvolvimento de software para simulação de motores com dispositivos de partida baseada na integração do atp com o toprede

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Arquiteturas eficientes para sensoriamento espectral e classificação automática de modulações usando características cicloestacionárias

The increasing demand for high performance wireless communication systems has shown the inefficiency of the current model of fixed allocation of the radio spectrum. In this context, cognitive radio appears as a more efficient alternative, by providing opportunistic spectrum access, with the maximum bandwidth possible. To ensure these requirements, it is necessary that the transmitter identify opportunities for transmission and the receiver recognizes the parameters defined for the communication signal. The techniques that use cyclostationary analysis can be applied to problems in either spectrum sensing and modulation classification, even in low signal-to-noise ratio (SNR) environments. However, despite the robustness, one of the main disadvantages of cyclostationarity is the high computational cost for calculating its functions. This work proposes efficient architectures for obtaining cyclostationary features to be employed in either spectrum sensing and automatic modulation classification (AMC). In the context of spectrum sensing, a parallelized algorithm for extracting cyclostationary features of communication signals is presented. The performance of this features extractor parallelization is evaluated by speedup and parallel eficiency metrics. The architecture for spectrum sensing is analyzed for several configuration of false alarm probability, SNR levels and observation time for BPSK and QPSK modulations. In the context of AMC, the reduced alpha-profile is proposed as as a cyclostationary signature calculated for a reduced cyclic frequencies set. This signature is validated by a modulation classification architecture based on pattern matching. The architecture for AMC is investigated for correct classification rates of AM, BPSK, QPSK, MSK and FSK modulations, considering several scenarios of observation length and SNR levels. The numerical results of performance obtained in this work show the eficiency of the proposed architectures

Análise quali-quantitativa do deslocamento da camada-limite em carrocerias veiculares

Dois dos principais objetivos no estudo da aerodinâmica de veículos é a segurança e o desempenho. Esses objetivos podem ser alcançados através do desenvolvimento de dispositivos que modifiquem o escoamento de ar ao redor do veículo e também através de alterações da forma das superfícies externas. O perfil mais baixo da frente do veículo, por exemplo, tem grande influência sobre o coeficiente de penetração aerodinâmica (Cx) e posteriormente sobre grande parte da distribuição de pressão ao longo da superfície do veículo. O objetivo deste trabalho foi de analisar o comportamento aerodinâmico que incide sobre 2 (dois) tipos de carrocerias de veículos, baseado em experimentação em túnel aerodinâmico, visando determinar a eficiência aerodinâmica de cada uma delas. Foram comparados dois modelos de veículos, sendo um deles com configuração familiar, muito comum nas grandes cidades e outro modelo com configuração esportiva mais voltado para o desempenho, ambos com escala 1:18. Para a realização do experimento foi construído um túnel aerodinâmico do tipo soprador com circuito aberto, onde foram analisadas as distribuições de pressão nas superfícies inferiores e superiores da carroceria dos modelos e o deslocamento da camada-limite. Tomando-se por base toda a teórica deste trabalho, com relação à aerodinâmica de carroceria, considerou-se nesta dissertação que essa filosofia de pesquisa é capaz de gerar reflexos positivos, que podem tornar os veículos cada vez mais eficientes e influenciar positivamente nos níveis de segurança e desempenho

Efeito Peltier em estruturas semicondutoras quasiperiódicas

There is nowadays a growing demand for located cooling and stabilization in optical and electronic devices, haul of portable systems of cooling that they allow a larger independence in several activities. The modules of thermoelectrical cooling are bombs of heat that use efect Peltier, that consists of the production of a temperature gradient when an electric current is applied to a thermoelectrical pair formed by two diferent drivers. That efect is part of a class of thermoelectrical efcts that it is typical of junctions among electric drivers. The modules are manufactured with semiconductors. The used is the bismuth telluride Bi2Te3, arranged in a periodic sequence. In this sense the idea appeared of doing an analysis of a system that obeys the sequence of Fibonacci. The sequence of Fibonacci has connections with the golden proportion, could be found in the reproductive study of the bees, in the behavior of the light and of the atoms, as well as in the growth of plants and in the study of galaxies, among many other applications. An apparatus unidimensional was set up with the objective of investigating the thermal behavior of a module that obeys it a rule of growth of the type Fibonacci. The results demonstrate that the modules that possess periodic arrangement are more eficient

Filmes nanométricos de FeN e ALN crescidos por sputtering e aplicações do efeito peltier

This study will show the capability of the reactive/nonreactive sputtering (dc/rf) technique at low power for the growth of nanometric thin films from magnetic materials (FeN) and widegap semiconductors (AlN), as well as the technological application of the Peltier effect using commercial modules of bismuth telluride (Bi2Te3). Of great technological interest to the high-density magnetic recording industry, the FeN system represents one of the most important magnetic achievements; however, diversity of the phases formed makes it difficult to control its magnetic properties during production of devices. We investigated the variation in these properties using ferromagnetic resonance, MOKE and atomic force microscopy (AFM), as a function of nitrogen concentration in the reactive gas mixture. Aluminum nitride, a component of widegap semiconductors and of considerable interest to the electronic and optoelectronic industry, was grown on nanometric thin film for the first time, with good structural quality by non-reactive rf sputtering of a pure AlN target at low power (≈ 50W). Another finding in this study is that a long deposition time for this material may lead to film contamination by materials adsorbed into deposition chamber walls. Energy-dispersive X-ray (EDX) analysis shows that the presence of magnetic contaminants from previous depositions results in grown AlN semiconductor films exhibiting magnetoresistance with high resistivity. The Peltier effect applied to commercially available compact refrigeration cells, which are efficient for cooling small volumes, was used to manufacture a technologically innovative refrigerated mini wine cooler, for which a patent was duly registered

Desenvolvimento e caracterização de dispositivos para reposição de filmes finos por descarga em cátodo oco

In the present work we use a plasma jet system with a hollow cathode to deposit thin TiO2 films on silicon substrates as alternative at sol-gel, PECVD, dip-coating e magnetron sputtering techniques. The cylindrical cathode, made from pure titanium, can be negatively polarized between 0 e 1200 V and supports an electrical current of up to 1 A. An Ar/O2 mixture, with a total flux of 20 sccm and an O2 percentage ranging between 0 and 30%, is passed through a cylindrical hole machined in the cathode. The plasma parameters and your influence on the properties of deposited TiO2 films and their deposition rate was studied. When discharge occurs, titanium atoms are sputtered/evaporated. They are transported by the jet and deposited on the Si substrates located on the substrate holder facing the plasma jet system at a distance ranging between10 and 50 mm from the cathode. The working pressure was 10-3 mbar and the deposition time was 10 -60 min. Deposited films were characterized by scanning electron microscopy and atomic force microscopy to check the film uniformity and morphology and by X-ray diffraction to analyze qualitatively the phases present. Also it is presented the new dispositive denominate ionizing cage, derived from the active screen plasma nitriding (ASPN), but based in hollow cathode effect, recently developed. In this process, the sample was involved in a cage, in which the cathodic potential was applied. The samples were placed on an insulator substrate holder, remaining in a floating potential, and then it was treated in reactive plasma in hollow cathode regime. Moreover, the edge effect was completely eliminated, since the plasma was formed on the cage and not directly onto the samples and uniformity layer was getting in all sampl

Saúde do trabalhador: entre os dispositivos legais e as práticas efetivas

The health worker is seized in this research beyond the mere applicability of legal devices concerning the legislation of Labor, in order to be established correlations with activities alluding to the public power in the ambit of State of Rio Grande do Norte (RN). This dissertation is an cutting of analysis circumscribed in the research, "Accidents at work: law, citizenship and justice," of the Grupo de Estudos Seguridade Social e Trabalho (GESTO) of Universidade Federal do Rio Grande do Norte (UFRN). The overall goal turned to apprehend and relate contradictory elements inherent compliance of Occupational Health and Safety (OHS) in the supermarket which showed the highest occurrence of legal violations recognized by the Labor Justice of RN in the period between 2006 and 2008 . The specific objectives turned to identify, from the condemnatory sentences, violations inherent in the protective direction of the OH & S legislation; analyze the relationship of health damages to workers at the supposed recognition of rights claimed in condemnatory sentences and correlate violations inherent in the legislation OSH impacts on the health of workers, from data contained in expert reports. The justification for perform the research backed up, among other factors, in the fact that class of activity has been presented as the most recurrent in condemnatory sentences, since it chose to focus the analysis on documentary evidence from the supermarket which showed greater expression in relation to violations of the OSH legislation. From a qualitative perspective, the methodological approach was based on content analysis of thirteen condemnatory sentences, handed down by the potiguar labor justice, and three expert reports from a large supermarket in the city of Natal/RN. Aftermaths are evidenced relating to the cyclical processes of reorganization of capital, demanding requirements for labor organizations whose strategies for survival include identifying mechanisms to extract as much of the work force. Structural determination and ideological context that puts into question the historical achievements of workers, for example the legal devices aimed at preventing workplace accidents, expressed in this research as relativized, showing limitations of reach, as was inferred the indemnities, by material and moral damages, arising from Work-Related Musculoskeletal Diseases (MSDs'S), recognized by the laborite judiciary

BMMobile: uma linha de produtos para dimensionamento de bombeio mecânico em dispositivos móveis

With the increase of processing ability, storage and several kinds of communication existing such as Bluetooth, infrared, wireless networks, etc.., mobile devices are no longer only devices with specific function and have become tools with various functionalities. In the business field, the benefits that these kinds of devices can offer are considerable, because the portability allows tasks that previously could only be performed within the work environment, can be performed anywhere. In the context of oil exploration companies, mobile applications allow quick actions could be taken by petroleum engineers and technicians, using their mobile devices to avoid potential catastrophes like an unexpected stop or break of important equipment. In general, the configuration of equipment for oil extraction is performed on the work environment using computer systems in desktop platforms. After the obtained configuration, an employee goes to equipment to be configured and perform the modifications obtained on the use desktop system. This management process equipment for oil extraction takes long time and does not guarantee the maintenance in time to avoid problems. With the use of mobile devices, management and maintenance of equipment for oil extraction can be performed in a more agile time once it enables the engineer or technician oil can perform this configuration at the time and place where the request comes for example, near in the oil well where the equipment is located. The wide variety of mobile devices creates a big difficulty in developing mobile applications, since for one application can function in several types of devices, the application must be changed for each specific type of device, which makes the development quite costly. This paper defines and implements a software product line for designing sucker-rod pumping systems on mobile devices. This product line of software, called BMMobile, aims to produce products that are capable of performing calculations to determine the possible configurations for the equipment in the design suckerrod pumping, and managing the variabilities of the various products that can be generated. Besides, this work performs two evaluations. The first evaluation will verify the consistency of the products produced by the software product line. The second evaluation will verify the reuse of some products generated by SPL developed

Ambientes residenciais controlados por dispositivos móveis: estudo, concepção e desenvolvimento de um aplicativo considerando a diversidade

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Geração de interfaces de usuário de sistemas Web para múltiplos dispositivos com o uso de componentes de IU

This work presents an User Interface (UI) prototypes generation process to the softwares that has a Web browser as a plataform. This process uses UI components more complex than HTML elements. To described this components more complex this work suggest to use the XICL (eXtensinble User Interface Components Language). XICL is a language, based on XML syntax, to describe UI Components and IUs. XICL promotes extensibility and reusability in the User Interface development process. We have developed two compiler. The first one compiles IMML (Interactive Message Modeling Language) code and generates XICL code. The second one compiles XICL code and generates DHTML code

Modelo de interoperabilidade para utilização dos recursos dos ambientes virtuais de aprendizagem através de dispositivos móveis

The technological evolution has been making the Distance Education accessible for a greater number of citizens anytime and anywhere. The potential increase of the supply for mobile devices integrated to mobile learning environments allows that the information comes out of the physical environment, creating opportunities for students and teachers to create geographically distributed learning scenarios. However, many applications developed for these environments remain isolated from each other and do not become integrated sufficiently into the virtual learning environments (AVA). This dissertation presents an interoperability model between mobile devices and distinct AVA based on webservices. For the conception of this model, requirements engineering and software architecture techniques were used. With the goal of showing the model viability, a mobile application focused on surveys has been developed, and additionally, the main functionalities related to the interoperability were tested

Investigando a compressão da percepção de distância em ambientes virtuais através da comparação entre dispositivos de visualização

The correct distance perception is important for executing various interactive tasks such as navigation, selection and manipulation. It is known, however, that, in general, there is a significant distance perception compression in virtual environments, mainly when using Head-Mounted Displays - HMDs. This perceived distance compression may bring various problems to the applications and even affect in a negative way the utility of those applications that depends on the correct judgment of distances. The scientific community, so far, have not been able to determine the causes of the distance perception compression in virtual environments. For this reason, it was the objective of this work to investigate, through experiments with users, the influence of both the field-of-view - FoV - and the distance estimation methods on this perceived compression. For that, an experimental comparison between the my3D device and a HMD, using 32 participants, seeking to find information on the causes of the compressed perception, was executed. The results showed that the my3D has inferior capabilities when compared to the HMD, resulting in worst estimations, on average, in both the tested estimation methods. The causes of that are believed to be the incorrect stimulus of the peripheral vision of the user, the smaller FoV and the smaller immersion sense, as described by the participants of the experiment.

Benchmarking e regulação do setor de distribuição de energia elétrica nacional: proposta para avaliação dos custos operacionais eficientes

In Brazil, the National Agency of Electric Energy (ANEEL) represents the energy regulator. The rates review have been one of its main tasks, which establish a pricing practice at a level to cover the efficient operating costs and also the appropriate return of the distributors investments. The changes in the procedures to redefine the efficient costs and the several studies on the methodologies employed to regulate this segment denote the challenge faced by regulators about the best methodological strategy to be employed. In this context, this research aims to propose a benchmarking evaluation applied to the national regulation system in the establishment of efficient operating costs of electricity distribution utilities. The model is formulated to promote the electricity market development, partnering with government policies ant to society benefit. To conduct this research, an integration of Data Envelopment Analysis (DEA) with the Stochastic Frontier Analysis (SFA) is adopted in a three stages procedure to correct the efficiency in terms of environmental effects: (i) evaluation by means of DEA to measure operating costs slacks of the utilities, in which environmental variables are omitted; (ii) The slacks calculated in the first stage are regressed on a set of environmental variables by means of SFA and operating costs are adjusted to account the environmental impact and statistical noise effects; and, (iii) reassess the performance of the electric power distribution utilities by means of DEA. Based on this methodology it is possible to obtain a performance evaluation exclusively expressed in terms of management efficiency, in which the operating environment and statistical noise effects are controlled.

Um middleware como interface padrão para acesso a dispositivos biomédicos

A grande diversidade na arquitetura de dispositivos de hardware, aliada aos seus diferentes protocolos de comunicação, tem dificultado a implementação de sistemas que necessitam realizar o acesso a esses dispositivos. Diante dessas diferenças, surge a necessidade de prover o acesso a esses dispositivos de forma transparente. Neste sentido, o presente trabalho propõe um middleware mult entrada e saída para acesso a dispositivos, como forma de abstrair o mecanismo de escrita e leitura de dados em dispositivos de hardware, contribuindo desta forma, para o aumento na produtividade dos sistemas, uma vez que os desenvolvedores estão focados apenas nos seus requisitos funcionais

Influência do método de síntese e caracterização de pós compósitos de NiO- Ce1-xEuxO2-δ para anodos catalíticos de células a combustível

Fuel cells are electrochemical devices that convert chemical energy into electricity. Due to the development of new materials, fuel cells are emerging as generating clean energy generator. Among the types of fuel cells, categorized according to the electrode type, the solid oxide fuel cells (SOFC) stand out due to be the only device entirely made of solid particles. Beyond that, their operation temperature is relatively high (between 500 and 1000 °C), allowing them to operate with high efficiency. Another aspect that promotes the use of SOFC over other cells is their ability to operate with different fuels. The CeO2 based materials doped with rare earth (TR+3) may be used as alternatives to traditional NiO-YSZ anodes as they have higher ionic conductivity and smaller ohmic losses compared to YSZ, and can operate at lower temperatures (500-800°C). In the composition of the anode, the concentration of NiO, acting as a catalyst in YSZ provides high electrical conductivity and high electrochemical activity of reactions, providing internal reform in the cell. In this work compounds of NiO - Ce1-xEuxO2-δ (x = 0.1, 0.2 and 0.3) were synthesized from polymeric precursor, Pechini, method of combustion and also by microwave-assisted hydrothermal method. The materials were characterized by the techniques of TG, TPR, XRD and FEG-SEM. The refinement of data obtained by X-ray diffraction showed that all powders of NiO - Cex-1EuxO2-δ crystallized in a cubic phase with fluorite structure, and also the presence of Ni. Through the characterizations can be proved that all routes of preparation used were effective for producing ceramics with characteristics suitable for application as SOFC anodes, but the microwave-assisted hydrothermal method showed a significant reduction in the average grain size and improved control of the compositions of the phases