No description available.

No description available.

Orientador: Luiz Eduardo Gomes Garcia Betting / Resumo: O padrão eletroencefalográfico mais comum em pacientes críticos é o distúrbio da atividade de base. Ondas trifásicas (OTs) constituem um padrão periódico classicamente relacionado às encefalopatias metabólicas. A maioria dos pacientes com OTs tem alteração do nível de consciência, e acredita-se que este padrão represente disfunção tálamo-cortical. Entretanto, o significado exato e o mecanismo das OTs permanecem desconhecidos. O objetivo principal deste estudo foi avaliar a origem das OTs utilizando o eletroencefalograma quantitativo (EEGq) e a tomografia computadorizada de crânio (TCC). 28 pacientes foram investigados. A análise dos focos das OTs foi realizada nas descargas promediadas para cada um dos indivíduos. Os mapas dos focos foram extraídos desta avaliação. As TCs foram submetidas à normalização e segmentação automática da substância cinzenta. Finalmente, uma análise de correlação voxel-a-voxel de todo o grupo foi realizada entre os mapas dos focos das OTs e as imagens da substância cinzenta. A análise do foco mostrou envolvimento principalmente do cíngulo anterior. A análise de correlação revelou áreas de correlação moderada positiva (giro do cíngulo posterior; r = 0,5) e negativa (caudado; r = -0,51) entre os métodos. / Abstract: The most frequent electroencephalographic pattern in critically ill patients is diffuse background slowing. Triphasic waves (TW) is a periodic pattern classically described in metabolic encephalopathic patients. Most patients with TW have altered level of consciousness, and this pattern is believed to represent thalamus-cortical dysfunction. However, the exact meaning and mechanism of TWs remains unknown. The main objective of this study was to evaluate the source of TWs using quantitative electroencephalogram (qEEG) and tomography (CT). 28 patients were investigated. Source analysis was performed in the averaged TWs for each individual. Source maps were extracted from this evaluation. CTs were submitted to normalization and automatic segmentation of gray matter. Finally, voxel-wise correlation analysis for the whole group was conducted between qEEG source maps and gray matter images. Source analysis showed involvement mainly of the anterior cingulate cortex. Correlation analysis disclosed moderate positive (posterior cingulate; r = 0.5) and negative (caudate; r = -0.51) correlations between the methods. / Mestre

It is a known problem that a Spinal Cord Stimulator (SCS) can interact with an Implantable Cardioverter Defibrillator (ICD) when both devices are implanted in the same patient. Interactions between the SCS and ICD can cause inappropriate therapy which can be harmful to the patient. While ICD devices have a distinct narrowband sensing bandwidth, the pulse configurations that current SCS devices deliver were not designed with this frequency region in mind. In this thesis, I recommend a new pulse configuration for SCS devices that will minimize the interaction between the two devices. I produce a theoretical equation for each pulse configuration in the frequency domain using the Laplace transform and present the results in Matlab. I also design my own SCS device to deliver multiple pulse configurations and use it to gather empirical data. The theoretical and empirical results are used to show the extent of the improvement between the new pulse and existing pulse configurations. The results prove that the new pulse configuration will significantly reduce crosstalk within the desired ICD bandwidth. A reduction in crosstalk will decrease the probability that an SCS will interact with a ICD device.

Made available in DSpace on 2014-12-17T14:56:13Z (GMT). No. of bitstreams: 1 FlavioGD_DISSERT.pdf: 434327 bytes, checksum: 80a9ab9e6651a6af8ae71caa0fd3bfec (MD5) Previous issue date: 2011-09-09 / This paper describes the study, computer simulation and feasibility of implementation of vector control speed of an induction motor using for this purpose the Extended Kalman Filter as an estimator of rotor flux. The motivation for such work is the use of a control system that requires no sensors on the machine shaft, thus providing a considerable cost reduction of drives and their maintenance, increased reliability, robustness and noise immunity as compared to control systems with conventional sensors / Esta disserta??o apresenta o desenvolvimento de uma simula??o computacional com a finalidade de demonstrar o funcionamento do controle vetorial para velocidade de um motor de indu??o trif?sico utilizando m?todo de estima??o pelo Filtro de Kalman Estendido, bem como os procedimentos necess?rios para sua implementa??o pr?tica. A motiva??o maior que influenciou a pesquisa est? na utiliza??o de um sistema de controle inovador que n?o necessita de sensores no eixo da m?quina (t?cnica sensorless), proporcionando desta forma uma consider?vel redu??o nos custos de acionamentos e manuten??o, aumento da confiabilidade, da robustez e da imunidade a ru?dos em rela??o ao controle de motores convencionais com sensores

No description available.