2009
2009 Doctorate Thesis: total vivas 08, from 41 to 48 - Page under Construction.
| 41th Doctorate Thesis |
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|---|---|
| Author: |
Luís Alberto Lucas |
| Title: | Sistema de Inferência Fuzzy Geral do Tipo-2 Aplicado à Classificação |
| Supervisor: |
Prof. Tania Mezzadri Centeno, Dr. |
| Area: |
Informatics |
| Keyword: |
General type-2 fuzzy sets; fuzzy inference systems; land cover classifier |
| Viva voce exam |
30 March 2009 |
| Abstract: |
This work proposes the development of a new tool based on general type-2 fuzzy sets to be applied to digital classification of data. The classification problem considered here regards the identification of areas of forest in satellite images. The goal is to assist users in tasks related to monitoring forest. The developed digital classifier employs an inference mechanism called "general type-2 scaled inference" to classify pixels in images according to their vegetation cover. Such classifier is innovative because, besides using general type-2 fuzzy sets, it can use specific and generic rules base (both in a hierarchical way) to reclassify pixels that remain unclassified. Such hierarquical reclassification leads to a compact rule base (with few rules). The reason why one should use type-2 fuzzy inference is that they present better performance than their type-1 counterparts, in spite of their bigger computational cost. The carried out tests showed, for sure, that the proposed system is better than the conventional fuzzy classifier usually employed in similar applications and its performance is comparable to the statistical likelihood classifier, proving to be an alternative choice to this last one. |
| Download |
[pdf] Only Portuguese |
| 42th Doctorate Thesis | |
|---|---|
| Author: |
Rita Zanlorensi Visneck |
| Title: | Production, stabilization and characterization of photosensitive long period gratings in optical fibers for sensors |
| Supervisor: |
Prof. José Luís Fabris, Dr. |
| Co-Supervisor |
Prof. Márcia Müller, Dr. |
| Area: |
Informatics |
| Abstract: |
This work shows the implementation of a writing system for long-period gratings production, by using a side point-by-point illumination with ultraviolet light, at Laser Laboratory in UTFPR. Gratings were written in optical fibers with a Nd:YAG laser operating at 266 nm. The spectral evolution of gratings was analyzed both during and after the writing process, along time intervals from 1 to 595 hours. The gratings were submitted to several characterizations aiming its application in physicochemical parameters sensing. For the assessment of gratings sensitivity to the external medium refractive index, fluid samples with refractive indices ranging from 1.0000 to 1.4315 were used. Changes of thermal sensitivity from negative do positive values were quantified, for temperature variations up to 24ºC, with behaviours transitioning from linear to nonlinear, depending on the refractive index of external medium. For the studies of sensitivities of longitudinal strain, the analyzed grating showed a low sensitivity value of – 0,19 ? 0,15 pm/?? in the range between 0 to 125 ??. A thermal characterization of the produced devices was carried out with a thermo element Peltier and with a laboratory furnace. For the Peltier the gratings were submitted to thermal cycles from – 1.5 ºC to 61.1 ºC. For the furnace the gratings were exposed to temperatures between 25 ºC a 1200 ºC without being completely erased. An experimental issue was the investigation about the thermal stabilization of gratings. Two different processes to reach the thermal stabilization were studied: annealing and quenching. The former consisted of annealing cycles with slow cooling whereas the later comprised of thermal cycles with sudden cooling from a maximum temperature of 425 ºC, the second one revealing to be more efficient to reach the thermal stabilization. The stabilized grating showed a non-linear thermal sensitivity ranging from - 0,044 nm/ºC to - 0,0044 nm/ºC within the temperature range from 20 ºC to 300 ºC. Owing to the inherent asymmetric characteristics of the process employed to record the gratings, the viability of using such devices as transducers for curvature sensing in different directions was studied, employing artificial neural networks to analyze the data. |
| Keyword: |
long period gratings, thermal stabilization of LPG, optical fiber sensors |
| Viva voce exam: |
15 April 2009 |
| Download |
[pdf] Only Portuguese |
| 43th Doctorate Thesis | |
|---|---|
| Author: |
Clovis Bombardelli |
| Title: | Electronic monitoring of coke fouling in oil processing |
| Supervisor: |
Prof. Dr. Hypolito José Kalinowski |
| Area: |
Informatics |
| Abstract: |
The coke fouling is a serious problem in the oil industry, mainly in equipment operating at high temperatures. This work presents a study to demonstrate the possibility of using the inlay of the coke as a transducer element to form a resistive sensor type, to provide an electrical signal representative of the growth and aging of the local self inlay. In order to demonstrate this, two categories of experiments have been carried out with two heavy oils fractions and two samples of real fouling coke incrustation originated by these oils in the industry. The experiments show good results, but also indicate that the signal combines both oil and incrustations conductivity. The coke produced during the experiment had non-adherent loose granules that were electrically disconnected between them. It was verified that the signal obtained during the batch controlled thermal cracking shows three distinct regions: at first, the material reacts within a first-order kinetic rate; at the intermediate region, fluid separation happens in two liquid phases and, finally, at the third region, solid coke deposition occurs, though immersed in a high electric resistivity oil, providing a much higher signal than the initial value presented by the oil. However, successive thermal cracking on the initial bed of coke showed progressive reductions in the values of the readings, indicating the tendency to be acquired by the aging of coke, to aggregate in a large structure of carbonaceous material with low electrical resistivity. Alternatively, to confirm, was measured the electrical resistance in samples of real inlay using the same conditions employed in the oils. These have showed a resistivity approximately 50 times smaller than the one for the oils. Testing of successive oil cracking on these inlays remain practically constant the electric resistance obtained as reading, confirming that the increase in conductivity is due more to the aging and cementation of grains of coke than the growth of the inlay itself. The tests also showed that once the encrustation acquires a resistivity lower than that of the oil, the signal becomes more meaningful and representative of the inlay. The signal, if is associated with an appropriate adjustment method, give the rate of growth of the embedded layer that can be used as a control parameter for the industrial process to minimize the problem of fouling by coke. |
| Keyword: |
petroleum, fouling, coke, sensors, electrical resistivity |
| Viva voce exam: |
11 September 2009 |
| Download |
[pdf] Only Portuguese |
| 44th Doctorate Thesis | |
|---|---|
| Author: |
Kleber Kendy Horikawa Nabas |
| Title: | Proposal of a model for performance analysis of the WFQ scheduler with LRD traffic |
| Supervisor: |
Prof. Walter Godoy Junior, Dr. |
| Co-Supervisor: |
Prof. Emilio Carlos Gomes Wille, Dr. |
| Area: |
Telematics |
| Abstract: |
Técnicas de gerenciamento de filas e descarte de pacotes são empregadas pelos escalonadores de pacotes presentes nos roteadores internos de uma rede de telecomunicações. Devido às características auto-similares do tráfego presente nas redes, o desenvolvimento de modelos para análise de desempenho de protocolos e de elementos de rede é enormemente dificultado. Tais características auto-similares são oriundas da ação dos protocolos predominantes nas redes em questão, e dos mecanismos fim-a-fim de controle de congestionamento existentes, determinantes no comportamento do fluxo de informações entre diferentes camadas na hierarquia de protocolos TCP/IP. Esta tese tem como objetivo principal propor modelos analíticos de baixo esforço computacional que permitam fazer uma análise de desempenho de um nó de rede (podendo este nó ser do tipo: DiffServ, IntServ, IP, Multi Protocol Label Switching, entre outros) com o escalonador WFQ. O tráfego considerado é do tipo TCP, devido ao fato que este protocolo é o mais utilizado na Internet atualmente, apresentando, portanto, características auto-similares. Foram desenvolvidos modelos para o escalonador WFQ quando o mesmo é alimentado com tráfego Poissoniano e tráfego do tipo auto-similar. O primeiro modelo está baseado em uma cadeia de Markov bidimensional para representar o comportamento do escalonador WFQ alimentado por dois fluxos de prioridades diferentes. O segundo modelo faz uso de duas filas separadas com taxas de serviço ajustadas de modo a simular o comportamento do escalonador WFQ. As filas são do tipo M[X]/M/1/B para levar em conta o comportamento auto-similar do tráfego. Como resultado, mostra-se que o segundo modelo é capaz de estimar as métricas de desempenho, com erro aceitável, dentro de uma faixa adequada de valores dos parâmetros do sistema, conforme demonstra a validação de resultados conduzido com uso do software NS-2. |
| Keyword: | WFQ, LRD traffic, Poisson traffic |
| Viva voce exam: | 18 September 2009 |
| Download |
[pdf] Only Portuguese |
| 45th Doctorate Thesis | |
|---|---|
| Author: |
Lia Yamamoto |
| Title: | |
| Supervisor: |
Prof. Lúcia Valéria Ramos de Arruda, Dr. |
| Area: |
Informatics |
| Keyword: |
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| Viva voce exam: |
27 October 2009 |
| Abstract: |
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| Download |
[pdf] Only Portuguese |
| 46th Doctorate Thesis | |
|---|---|
| Author: |
Luiz Carlos Felizari |
| Title: | |
| Supervisor: |
Prof. Lúcia Valéria Ramos de Arruda, Dr. |
| Area: |
Informatics |
| Keyword: |
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| Viva voce exam: |
04 December 2009 |
| Abstract: |
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| Download |
[pdf] Only Portuguese |
| 47th Doctorate Thesis | |
|---|---|
| Author: |
Edson José Pacheco |
| Title: | MorphoMap: Automatic Mapping of Clinical Documentation to a medical terminology. |
| Supervisor: |
Prof. Percy Nohama, Dr. |
| Area: |
Biomedical Engineering |
| Abstract: |
Clinical documentation requires the representation of fine-grained descriptions of patients' history, evolution, and treatment. These descriptions are materialized in findings reports, medical orders, as well as in evolution and discharge summaries. In most clinical environments natural language is the main carrier of documentation. Written clinical jargon is commonly characterized by idiosyncratic terminology, a high frequency of highly context-dependent ambiguous expressions (especially acronyms and abbreviations). Violations of spelling and grammar rules are common. The purpose of this work is to map free text from clinical narratives to a domain ontology (SNOMED CT). To this end, natural language processing (NLP) tools will be combined with a heuristic of semantic mapping. The study uses discharge summaries from the Hospital das Clínicas de Porto Alegre, RS, Brazil. Parts of these texts are used for creating a training corpus, using manual annotation supported by active learning technology, used for the training of NLP tools that are used for the identification of parts of speech, the cleansing of "dirty" text passages. Thus it was possible to obtain relatively well-formed and unambiguous noun phrases, heuristics was implemented to semantic mapping between these noun phrases (in Portuguese) and the terms describing the SNOMED CT concepts (English and Spanish) uses the technology of morphosemantic indexing, using a multilingual subword thesaurus, provided by the MorphoSaurus system, the resolution of acronyms, and the identification of named entities (e.g. numbers). In this study, 80 per cent of the summaries are analyzed and manually annotated, resulting in a domain corpus that supports the specialization of the OpenNLP system, mainly following the paradigm of statistical natural language processing (the accuracy of the tagger obtained was 93.67%). Simultaneously, several techniques have been used for validating and improving the subword thesaurus. To this end, the semantic representations of comparable test corpora from the medical domain in English, Spanish, and Portuguese were compared with regard to the relative frequency of semantic identifiers, improving the corpus coverage (2% to Portuguese, and 50% to Spanish). The result was used as an input by a team of lexicon curators, which continuously fix errors and fill gaps in the trilingual thesaurus underlying the MorphoSaurus system. The progress of this work could be objectified using OHSUMED, a standard medical information retrieval benchmark. The mapping of text-encoded clinical information to a domain ontology constitutes an area of high scientific and practical interest due to the need for the analysis of structured data, whereas the clinical information is routinely recorded in a largely unstructured way. In this work the ontology used was SNOMED CT. The evaluation of mapping methodology indicates accuracy of 83.9%. |
| Viva voce exam: |
16 December 2009 |
| Keywords: |
Ontologies, SNOMED CT, Information Retrieval, natural language processing, electronic medical records. |
| Download |
[pdf] Only Portuguese |
| 48th Doctorate Thesis | |
|---|---|
| Author: |
Ionildo José Sanches |
| Title: | Superposition of thermography and magnetic resonance images: a new tridimensional medical image modality |
| Supervisor: |
Prof. Humberto Remigio Gamba, Dr. |
| Area: |
Biomedical Engineering |
| Abstract: |
Infrared (IR) imaging is a noninvasive diagnostic technique that allows the examiner to evaluate and quantify changes on skin surface temperature. Since changes over the human body surface temperature are continuous, it is difficult to associate anatomical details, as well to associate skin temperature with internal structures or organs. Though providing significant information to clinical diagnosis, this technique does not allow evaluating anatomical details of the imaged region. In this work it is presented a new image fusion method for combining 3D Magnetic Resonance Images (or Computed Tomography) and 2D thermal images. The result is a 3D thermographic imaging that can improve medical diagnosis of certain human diseases, such as peripheral vascular disease, diabetic foot, breast and thyroid tumors, sinusitis, cephalalgia, rheumatic disorder and others inflammations process, i.e., diseases that can be diagnosis through the body surface thermal mapping. In the development of this interdisciplinary work of Biomedical Engineering, the knowledge of Digital Image Processing, Computer Graphics, Machine Vision, Computer Programming, Radiology, Medical Imaging and Thermography, was necessary, interacting with areas of Medicine, Computer Science and Electrical Engineering. First, magnetic resonance images (MRI) or computed tomography (CT) from region of interest are acquired. In a second experiment, a set of IR images is acquired. From the MRI or CT data, 2D projections are generated in the same direction/orientation of the tomographic planes. Then, the generated projections and the IR images are registered. Next, the registered IR images set is combined and projected over the 3D-MRI or 3D-CT. The result is a fused image that combines the information contents from two different medical images modalities. The excellent results obtained with the new methodology demonstrate that it can aid medical diagnosis. |
| Keywords: |
infrared imaging, thermography, magnetic resonance, image registration, image fusion. |
| Vica voce exam: |
17 December 2009 |
| Download |
[pdf] Only Portuguese |
