RCAAP Repository

The topic of this dissertation is related to the telecommunications industry in very important academic and business. The signal transmission through radio links is critical to meeting a specific locality or a season of a telecommunications carrier, and the transmission capacity of its greatest limitation. The microwave links has several benefits, being the period of deployment and cost are more favorable compared to optical fiber, since the latter requires that the service is over small distances so that there is no encumbrance design service. Currently , urban centers are increasingly embedded systems of care through radio, because of the difficulty of operation and maintenance (O&M) found in fiber optic systems . The radio link is coming from indoor and outdoor equipment , which capture and transmit radio signals from the transmitting and receiving antennas operating with electromagnetic waves . According to the frequency set in the radio link and via software accurate , the engineer in charge can make a project sizing radio without the need to participate in the field survey. A decisive factor for the development of a project is the infrastructure which will be installed vertical antennas , because depending on that , the antennas will be at a height that will not be conducive to a good performance of the radio link , because every project requires a scaling special attention to the correction factor of the earth - ke to release all or part of the Fresnel zone . Through these parameters mentioned , the designer can detail your project according to the frequency and distance of the link being built through trusted software . The radio links operating above 10 GHz are subject to attenuation due to rain , since the relationship between the frequency are directly proportional , but every link is designed in accordance with a conventional safety margin because attenuation can occur and if it happens to a value higher than expected , the link may lose communication . The adaptive modulation is an important feature because radio links that are susceptible to attenuation due to rain may lose communication , but this function will switch the link below to modulations causing an increase in the threshold of reception and transmission power while maintaining the link in communication , but with a lower transmission rate.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Power Quality is an issue that has assumed paramount importance in the sector of energy production in Brazil and abroad. This is due in principle to the great demand for electric energy and the need to better control the generation, transmission and distribution of this product. The biggest problems for this purpose are the occurrences of electrical disturbances that impair performance, service life of equipment and devices, produce disruptions and damage industrial processes and domestic network. Voltage transients on the line, caused by activation of electrical machinery, causing voltage sags relevant, is the most prominent theme of this dissertation work. Among the most important electrical machines used by the industry, is the Phase Induction Motor (MIT). Therefore, a study prepared and consistent on the effects of activation of these machines can reveal important aspects and define how we can improve the quality of energy, taking decisions about costs and control, knowledge, and many other aspects. This paper talks about tests made with scientific methodology and based on computer simulations, substantiated by experiments carried out in laboratories at the University Santa Cecilia (Santos, SP) and supervised by Prof.. Dr. Luciano Martins, FEELT of the UFU (Uberlândia, MG), with the collaboration of Prof. Engineers. Dr. Silverio Santos y Penin (CDMC and UNISANTA, SP) and Prof. Dr. Edval Deoboni (EMAE, SP). Tests of MIT drives with the help of measuring equipment and several comparisons with computational simulations.

Program induction involves the inductive discovery of a computer program that produces some desired output when presented with some particular input. An example is the symbolic regression, a modeling tool that seeks mathematical expressions of functions to fit a given multivariate data set, mapping input variables to output variables of control. The genetic programming, a subarea of evolutive computing that uses an analogy of Darwin s evolutionary theory and some ideas from the genetics field, is an automatic technique for producing a computer program widely used to solve such problems. However, implementing genetic programming is not trivial for most professionals, besides demanding high computational power. This work presents a parallel implementation of genetic programming simple to handle, optimized for computers with multicore architecture, and satisfying competitive criteria of structural simplicity model and prediction accurate model, through a special multi-objective flavor of a genetic programming, called Pareto Genetic Programing. The proposed implementation has performance gains proportional to the amount of available cores in use, and has been successfully applied to several types of regression problems.

The Software Defined Radio is revolutionizing the concept of signal processing devices. The Software Defined Radio provides a radio architecture that allows flexible switching of the radio function, possibly in real time, with a process that ensures a desired quality of service. This flexible hardware architecture combined with flexibility in software architecture allows integration with networks and with totally different interfaces. From this concept, this work presents applications using the Universal Software Radio Peripheral and the GNU Radio software as a proposal to equip telecommunications, biomedical, electrical and electronic laboratories. Also, this work presents the creation of new processing blocks using the GNU Radio, with the goal of applying the Daubechies Wavelet Transform to analyze cardiac signals and also for voice signals processing in order to perform file compression.

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The use of renewable energy sources such as, solar, wind, fuel cells, biomass, among others, have attracted great interest in the field of power generation, as a consequence of the environmental problems that have affected the whole Earth. Brazil presents a great potential in solar electric power generation which has been used by some public and private institutions, despite the high initial implementation costs. In this context, the integration of photovoltaic energy as an alternative power source in the Brazilian energy matrix gained considerable emphasis in the years 2011 and 2012 in the national and international scenarios. After the approval of the Normative Resolution 482 in April 17th, 2012, ANEEL established the general conditions for microgeneration (up to 1MW) and minigeneration (up to 100kW) accessing the electric power distribution systems, as well as the net-metering compensation system of the electric power generated. Since then, several applications for grants for connecting PV systems to the low and medium voltage grid have been performed. In this context, this dissertation presents the design of a 6.58kWp photovoltaic system in the city of Uberlândia, Minas Gerais, following the standards established by that Normative Resolution and in accordance with the ND 5.30, which establishes the criteria for connecting new micro and mini distributed generation systems to the low-voltage grid. The photovoltaic system was installed in the company PGM Suporte em Tecnologia LTDA in partnership with ECONOVA Sistemas de Energia LTDA and Núcleo de Pesquisa em Eletrônica de Potência (NUPEP) at Universidade Federal de Uberlândia (UFU). Within this subject, design criteria of PV systems, measurement results of the electric power generation, environmental and economic impacts are presented in this work. Design criteria, measurement results of the electricity generated, tons of CO2 not emitted through the use of PV systems compared to power sources that depend on combustion of fossil fuels, costs and results of the assessments about power quality at the point of common coupling of the installation are presented in this work.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

The Near Field Communication (NFC) and mobile payments are two areas in constant development in current market. Today when we use the wallet, we can found cash of different values, coins, debit and credit cards of one or two banks, loyalty cards from restaurants and shopping receipts. Even though these items found in the wallet have a symbolic value of utility, they are becoming outdated, as a plethora of plastic and paper that will not make much sense in the near future. The revolution of mobile payments is imminent and is already happening. Instead of wallets, we have mobile phones with NFC on their hardware and software that transform them into a digital wallet (e-wallet). What matters now are not the papers and cards, but stay connected to your e-wallet account\'s that has your bank details. The main objective of this dissertation is to present the development of a mobile payment system called S-Wallet system, using the technology of NFC. This work also includes the development of a protocol for mobile payments, the protocol SWEP, which performs the whole process of message exchange, data exchange and payment execution. Besides the App S-Wallet, an application interface to android users use. In addition, an account that stores users data remotely, called S-Wallet account. As part of the evaluation of the S-Wallet, we perform tests of integration of all the entities of the system. These tests showed that the S-Wallet provides usability, security and privacy to users. Further, we had performed usability tests with users showing that the S-Wallet system is easy to use and we had indicated it for the real scenario studied: payment between two users, peer-to-peer (P2P) and retail vending. This work shows that the NFC technology is secure for mobile payments and is very useful for its expansion in the commercial sector.

The JPEG standard has been used for a long time as the algorithm of reference for the compression of monochrome images, and that compression would be applied separately to components of color images. In the process of image compression JPEG utilizes standard quantization table in an independent way to the application. Using JPEG, the quality loss of the reconstructed image is a direct function of the quantization process and this can be seen in the peak signal to noise ratio (PSNR) as in terms of subjective quality. A method for the generation of quantization tables for the JPEG algorithm applicable to monochrome and color images is showed and it is addressed to specific applications, that is, compression of natural images, etc. Another innovation is the use of Genetic Algorithms in the search for a quantization table linked to a class of images and this provides a superior PSNR, if compared with that obtained by the JPEG algorithm with its standard quantization table. The comparisson between the algorithm proposed in this Project and the JPEG standart is also done through the application of a blockiness metric for compressed images, highlighting which algorithm will provide the lowest blocking artifact.

Several studies in healthcare require the acquisition and analysis of biological signals. The stage of acquisition of these signals depends on protocols, equipment and specific techniques, and is a compulsory part of the schedule of several studies. For this reason, it is interesting to be able to optimize it. The main objective of this work is the development in an emulator hardware of biological signals for teaching and learning in area of biomedical engineering and aid to new technologies arising from the use of biological signals. In this context, the development of equipment capable of emulating and simulating biological signals becomes relevant because, with them, you can subtract the acquisition step, saving time and at aiding aimed studies its processing. These devices provide a biological signal in analog form that was previously stored digitally in a database emulating them, or simply simulating these signals when they are generated by computer programs. An important application for the emulators and simulators of this kind, is to evaluate the accuracy, precision and performance of the systems processing signals in real time. Thus, this study includes a literature review that describes the importance of the study of biological signals and proposes an architecture and organization of an emulator / simulator called BioSim in order to improve techniques for the study of these signals as well as to evaluate and calibrate equipment that use these signals. The BioSim corresponds to a four-channel system consisting of processing modules, MAPLE ( ARM Cortex M3 ) and Arduino MEGA ( ATMEGA 2560 ) , with a storage capacity of 4 Giga Bytes per channel , through a micro SD card ( SanDisk ), and a man-machine interface comprising a liquid crystal display and buttons for navigation. To evaluate the developed equipment were considered signs simulated by a computer program, in emulation of database a several biological signals collected in previous studies by our research group of the Biomedical Engineering Laboratory of the Federal University of Uberlândia - BioLab. The results suggest that the device is able to simulate and emulate biological signals in real time, sampled to 20 kHz, with a resolution of 12 bits. This will allow the optimization of the acquisition process of the biological signals, reducing the time for carrying out research in area of the Biomedical Engineering.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Given the scenarios of increasing world population, the concentration of CO2, fuel costs, global consumption of energy and climate change, there was a need to search for alternative energy sources. In this context, solar photovoltaic, the result of research and investments over the past five decades, had a great impact in the last decade, recording a significant increase in the production of photovoltaic cells and modules and installations of photovoltaic systems worldwide. One of the goals of this work was to study the behavior of PV modules by partial shading situations in different conditions of temperature and solar radiation. Within this partial shading scenario that impacts virtually all electrical parameters of a module, the study and calculation of the series resistance of the modules was done in conditions of partial shading proposals to verify the relationship between the value of the series resistance and the state of shading partial, allowing identification of a possible state of shading from monitoring the resistance series. Another objective of this work was to apply Artificial Intelligence (AI) resources in the form of Artificial Neural Networks (ANN) to, after the proper training and learning of ANN from the database collected in the field under conditions of partial shade, they can identify the parameters of the PV modules within the various conditions of partial shading proposals. To pursue the objectives of this work four photovoltaic modules were used, two with 40 W nominal power with over fifteen years of manufacturing, assigned by the Instituto Federal de Goiás (IFGoiano) Urutaí Campus, at the city of Urutaí-GO and two new without any use of 75 W nominal power assigned by the Center for Research on Alternative Energy Sources, School of Electrical Engineering, Universidade Federal de Uberlândia (UFU).

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

The use of computer graphics technology, applied in different areas of health is certainly notable, having positive and reliable results, thus pushing for innovative techniques. The current literature still lacks of collateral to support surgeons and their patients on the orthognathic surgery field. Orthognatic Surgery usually is applicable to patients who have used traditional braces, and did not obtain satisfactory results. The Orthognatic Surgey provides a manner to do a jaws breakdown through a controlled set of procedures with certain security levels. It is through surgical procedure that a perfect dental occlusion is expected. It is important to note that patients suitable for this procedure should have very pronounced symptoms, with origin in the relation between the teeth, muscles and bones. These problems may cause a set of symptoms, among them are pain in the face, incorrect tongue and TMJ positioning, headaches and stomach disorders ( due to improper chewing) , respiration and phonation issues. This paper describes a 3D analysis and simulation of a procedure for orthognathic surgery, with the goal of providing a better assistance for surgical planning using CT scans efficiently. There is also a motivation to include the software code written in this dissertation as part of the InVesaliusTM system, from CTI, in order to leverage the capabilities of orthognatic surgery planning and simulation and its expected outcomes.

This study proposes an approach to analyze EMG signals using wavelets transformed as a method of signal features extraction. The adopted methodology is based on the study of the aggregated power envelope and the aggregate power spectrum envelope, which are obtained from the distribution of energy of a certain signal, based on the potency of wavelet coefficients, showed like wavelets spectrograms or from a wavelet scalegram. EMG signals were captured in the surface of the human skin and came from the right leg rectus femoris muscle in a static condition (isometric), also from the flexor muscle form the right hand in dynamic contraction (isotonic) and also form a train of motor unit action potential (MUAP) form the First Dorsal Interosseous muscle during dynamic contraction. Having those signals, there were taken two research phases: extraction of the feature based on the analytical wavelet transformed (AWT) in muscles during contraction (isometric and isotonic) and the phase of detection of MUAPs. In the AWT phase, considering the calculation of the envelopes in the timefrequency chart (spectrogram), the results shoed that the wavelet transformed can be applied for extraction of spectral content of the signal and also showed the possibility of verifying the potency signal spectrum and the energy of such signal intimae. Those variables were according to the expected features for EMG signal, reported by literature. In the second phase, MUAP detection, it was used the calculation of the envelopes based on the scalegram, having as a main wavelet the Daubechies of 4 (db4), Coiflet of 4 (coif4) and Symlet of 5 (sym5) . The result showed that the method allowed to locate in time of MUAPs and showed that it is sensible enough to detect signals form motor units, far from the sensor, which contribute to formation of the EMG signal. The use of the wavelet Db4 showed to be better to detect the muscle activity on the beginning of it ( set-on ), because the Db4 is similar to a MUAP. This work proposes that future studies can be based on the research of families of wavelets, using of the method of the aggregated power envelope to control proteases for arms, or hands for example. It is also proposed studies for detection of MUAPs as an important tool for muscles evaluation, in diagnosis of miopathologies and neuro-muscle disjunctions, envelope features extraction process for other biomedical signals, such as EEG and ECG.

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