RCAAP Repository

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Nowadays, the high level of complexibility designated by duties in many areas are expecting more from the man his natural senses can offered him. The use of Virtual Reality techniques can auxiliate the development of perception, interaction and consequently the every day productivity. Basing it in this idea, this research has as objectivity to create an application to offer the user information about the virtual urban rotes. This dissertation present a architecture for construction of a virtual environment which reproduce virtual urban rotes having as instrument the search of the best rote, a algorithm based on evolutive computation, denominated Genetic Algorithm, and, as instrument of visualization of the scene of the virtual rote, streets of a city in three dimensions, a Virtual Reality. A prototype was built having as references a neighborhood of a city seen under two points of view. The first one in two dimensions allowing the choice of a start point (origin) and an end point (destiny) and a way to be covered between the points with the shortest distance possible. For treating of a probabilistic problem, where there are innumerous possibilities of solution, the genetic algorithm were choose for making framing in this type of problem possible. The second point of view, in three dimensions, beyond offer to be virtual environment with possibilities of free navigation on the scene of a city, proportionate to the user navigation for ways built by the model 2D. The 3D model was built with the support of the graphic library OpenGL and the geometric model of the city was drawn with the use of a specific tool of graphic modeling been imported to the prototype. The system use for both points of view (2D and 3D) the same model, which proportionate a portability in relation to the scenes (cities), so it s enough to have a geometric model of a neighborhood or city to the application functioning. The system was evaluated by researchers and specific users and the results reached allowed concluding that the same is efficient and applicable.

The visualization of a 3D image obtained from computerized tomography examinations has shown itself to be an important factor for increasing the quality of medical diagnoses and, consequently, treatment efficacy. There already exist on the market, several visualization softwares, which use different techniques to show the 3D tomography image. However, to show a high quality 3D image, sophisticated devices must be used to obtain slices, close to one another, thus increasing the incidence of X-ray given to the patient. An interpolation slice method which resulted from the TC examination produces good results, and is able to reduce the X-ray incidence upon the patient. This method must reconstruct the curvature from the patient s internal structures without using slices in close proximity. This work proposes a method of 3D image interpolation, composed of a juxtaposition of the slices from CT examination results. The goal of this method is to increase the quality of 3D visualization through the production of sharp and precise structure contours. This thesis proposes the division of the interpolation method into two steps. In the first step, the goal is to obtain an initial representation of the image in 3D, which is composed of real slices as well as virtual slices which are referred to in this work as initial virtual slices. In the second step, the empty spaces of the structure are recovered by the 3D image inpainting process. This work also proposes a method to obtain the initial virtual slice and two different methods for inpainting the 3D image. These inpainting methods are the transversal slice line prolongation method and the transportation and diffusion of information. Both methods use the differential equation theory. The transportation and diffusion of information method shows better results than other methods proposed in this work, besides this, this method presents better results than the linear interpolation and Goshtasby et al. [1] methods also implemented in this work. Visual and numerical comparisons are used to obtain this conclusion. The numerical measures used are statistical correlation, the PSNR and the Hausdorff distance [2]. The transportation and diffusion of information method shows itself able to produce better results than all the other tested methods. Besides this principal contribution, this work also developed a KIT to implement 2D and 3D CT visualize applications.

OCaml and other ML like languages does not provide developer with a native GUI. Therefore one must use a third party GUI, like TCL/TK or GTK. This requires final users to search the Internet for a GUI library, download it, install it, etc. Most final users are not up to the task. Therefore we decided to create a GUI interface entirely written in OCaml, that does not require any external library to work, and that has a very small footprint. Compiled programs occupy as little as 300Kbytes on disk. The system works equaly well on Windows, Linux, or any other operational system with an OCaml port. It has four kinds of widgets: Buttons, refresh devices, parsers, and Emacs-like mini-editors. The Emacs widgets work with plain text or mask-driven forms; they offer a practical and simple method for data input. Since OCaml is a strong typed functional language, this application is pratically bug free.

The purpose of this work is to generate a better Quantization Table for a group of natural images and medical images using the Genetic Algorithm method in the process of compression JPEG. The fitness function of the population will be analyzed and the probability of selection the better pairs of chromosomes or matrix, and we will also breach means to improve the results through modifications of the input parameters. In the previous processing of the coded image it is necessary to know very well the Quantization Table to achieve an image with less loss and therefore, better final quality. The method of Genetic Algorithm applied to this program is based on mechanisms of natural selection and reproduction for a set of natural and medical images and furthermore it allowed for the creation of not one but various Tables with SNR higher than those produced by the JPEG Table since it stimulated the principal characteristics of this method in programming such as: codification of defined parameters; the process of search for better matrix starting from a group of matrix and not a simple matrix; information obtained of an objective determined function (fitness function) and the use of the probabilistic rules of transition. Based on the results obtained in this work, we can recommend the use of Genetic Algorithm for natural images and human eye images with a compression rate up to 30:1 and a great reconstructed image quality.

This work presents as main goal to implement a computational application that allows the user create MIDI musical sequences for guitar. The difference of the musical sequences generated by the software resides in the fact that each musical note of the MIDI sequence can be modified for the inclusion of humanized articulation, individualized and with timbral qualities like an acoustic instrument. The sound resulted of these sequences is render in other musical formats, such as Wave. The application interface and functions are developed in pure functional paradigm (based on lambda calculus). This choice avoids the use of dlls and other resources strongly dependent of operational system version. The choice of the functional language Clean is justified in this work, by the reason of being one of the two more efficient languages of the actuality (according to analysis of specialized benchmarks). In the implementation of the manipulation functions of SMF files and interface generated libraries that will allow extending this work for another soloists (monophonic) instruments. This application presents an adherent interface with all kinds of users. In order to manipulate SMF files, many libraries were developed, allowing extending this work for other soloists (monophonic) instruments. This application presents an adherent interface with all levels of users.

The extraction of signal components from Auditory Brainstem Response (ABR), referred to as Jewett waves, is an important step in studies regarding the investigation of the behavior of the auditory system. However, this evaluation is complex and depends on the experience of the specialist. In this context, the objectives of this research are to compare ABR analyses provided by different examiners, and also to verify the possibility of discrimination of Jewett waves through the analysis of instantaneous attributes (IA) of time-series, estimated by the Hilbert Transform (HT). The ABR data were collected from healthy subjects, following the criterion of auditory normality, and analyzed by four examiners. A statistical study aiming to verify the coherence among these analyses was performed. The HT was then employed for calculating the IA from ABR signals. The compatibility among the results provided by the examiners was verified. The analysis of IA suggests that they can be used as discriminative features for the different waves that compose the ABR. These results are relevant for the development of tools for automatic ABR analysis. Furthermore, it contributes to investigations that aim to discriminate ABR related to distinct disorders.

Universidade Federal de Uberlândia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

This dissertation presents and analyzes the results of theoretical investigations and experimental of the thermal behavior of transformers the dry, isolated with resin epoxy, under conditions sinusoidal and non sinusoidal of tension and current. Development a study of the losses in the several parts of the transformer, standing out the losses for currents parasites proposed by the norm ANSI/IEEE [3] and was compared with other [5], more exact, that takes in consideration the geometry of the transformer. Inside of this context present new equations for the temperature elevations, rendiment, useful life and derating of the transformer. A thermal model is used to estimate the temperature elevations in the transformer. Experimental studies are led in a prototype of a transformer trifásico the dry, isolated with resin epoxy, delta/estrela, 5 kVA especially built for the accomplishment of temperature tests, with sensor thermal located in several points of the equipment. This procedure makes possible the comparison among the results computations, with views to the validation of the proposal of the thermal modelling of first order.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

This thesis applies computer graphics to two important fields of Biomedical Engineering. Firstly, in order to provide new software for interdisciplinary education, an interactive Virtual-based platform was developed, presenting a tridimensional visualization of the neuron and of its major microestructures. Such platform enables an overall view of the neural cell, including particular details in a microcellular level. Several issues regarding the tridimensional reconstruction of neuroanatomical strucutures based on photos taken from real-life tissues are discussed, leading to the implementation of a bidimensional atlas, that establishes connections between neuroanatomy and the clinical practice. Secondly, a system for the efficient and accurate estimation of the time intervals associated with swallow phases was developed, supposing videofluoroscopic images as inputs. The system performs pre-processing of such images by means of file conversions, followed by image analysis, that leads to the final estimation. A clinical experiment was carried out in order to validate the platform, yielding (allowing) a preliminar proposition for a normal pattern of swallow , which is based on the average-estimated swallow times. Results pointed out that the system may be considered, flexible, requiring simple hardware/software configurations, and also providing details on fractioning.

This work approaches the induction machine s technical viability on small hydropower plant instead of synchronous machines, as a viable economically alternative of generating electric energy, matching conventional and decentralized generation visualizing micro generation. This technology makes it possible to skirt a series of problems in the conventional model, as well as lowering tax of ambient impacts. According to the level of consumption, it could generate income for small proprietors, which results the possibility of great impacts on social order. This work presents a distributed generations evolution s synthesis. It also contemplates information about alternative sources of energy, distributed generation s impacts at compositing the energy matrix, as well as it s perspective. In addition to that, it focuses on the main advantages and disadvantages of the distributed generation, emphasizing the conventional electric energy generation model by means of small hydropower plant generation using synchronous and the model using induction machines which is proposed on the presented work. It also presents the development of an archetype, as well as the carried through experimental laboratory and field. At least, the work boards, through digital simulations, a study of agricultural distribution system s results of the prototype area, using the local net real data and simulating the injection of the gotten power of the prototype.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

This study presents a comparative study of the use of the CORBA architecture (Common Object Request Broker Architecture) and the .NET platform as an intermediate communication layer between distributed virtual environments. The main objective of this work is to develop a prototype based of platform .NET and the graphic library OPENGL that allows the communication among two or more distinct virtual environments, in a such way that actions taken in one environment modifies the reality of other environment and vice versa. Thus, the photosynthesis phenomenon has been taken into account as a case study (due to the Biology and Chemistry environments). Scalability and latency are the main parameters used to perform the proposed architecture comparison. Finally, it is important to say this work has been done to provide tools that can support the multidisciplinary education process. Therefore, it aimed to help distributed virtual environments.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior