No description available.

<p>GPGPU is a collective term for research involving general computation on graphics cards. A modern graphics card typically provides more than ten times the computational power of an ordinary PC processor. This is a result of the high demands for speed and image quality in computer games.</p><p>This thesis investigates the possibility of exploiting this computational power for image processing purposes. Three well known methods where implemented on a graphics card: FFT (Fast Fourier Transform), KLT (Kanade Lucas Tomasi point tracking) and the generation of scale pyramids. All algorithms where successfully implemented and they are tree to ten times faster than correspondning optimized CPU implementation.</p>

No description available.

The Karhunen-Loeve Transform (KLT) is a popular transform used in multiple image processing scenarios. Sometimes, the application of the KLT is not carried out as a single transform over an entire image Rather, the image is divided into smaller spatial regions (segments), each of which is transformed by a smaller dimensional KLT. Such a situation may penalize the transform efficiency. An improvement for the segmented KLT, aiming at mitigating discontinuities arising on the edge of adjacent regions, is proposed in this paper. In the case of moderately varying image regions, discontinuities occur as the consequence of disregarded similarity between transform domains, as the order and sign of eigenvectors in the transform matrices are mismatched. In the proposed method, the KLT is adjusted to guarantee the best achievable similarity via the optimal assignment and sign correspondence for eigenvectors. Experimental results indicate that the proposed transform improves the similarity between transform domains, and reduces RMSE on the edge of adjacent regions. In consequence, images processed by the adjusted KLT present better cohesion and continuity between independently transformed regions.

Made available in DSpace on 2014-06-12T15:55:49Z (GMT). No. of bitstreams: 2 arquivo2328_1.pdf: 4997289 bytes, checksum: 4012a5235a1aad082afe66cac56457eb (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2010 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A reconstrução 3D é uma área de pesquisa que consiste em recuperar modelos que representem com precisão e em 3D características de interesse de uma cena, através da extração de informações 3D a partir de imagens 2D. Estas informações podem ser relativas à estrutura de uma determinada cena, posicionamento e trajetória de câmeras, textura, dentre outras. Uma vez de posse de tais informações, podemos utilizá-las para os mais diversos fins, por exemplo, modelagem automática de objetos, sistemas de navegação autônoma de robôs, modelos computacionais de estruturas ou órgãos do corpo humano, posicionamento de elementos virtuais em cenas reais, dentre outros. Uma das formas mais difundidas de se realizar reconstrução 3D é utilizando sequências contíguas de imagens ou vídeos capturados por câmeras convencionais (monoculares). Neste tipo de reconstrução um dos desafios mais importantes é o rastreamento. Rastreamento é a capacidade de conseguir corresponder um conjunto de pontos em uma sequência de imagens, ou seja, dado um ponto A com coordenadas x e y, deve-se ser capaz de identificar o ponto A com coordenadas x e y na imagem seguinte da sequência, e que corresponde exatamente à mesma localidade da estrutura sendo rastreada. Neste contexto, o objetivo desta dissertação de mestrado foi avaliar os algoritmos de rastreamento mais utilizados para este propósito, ressaltando as características individuais de cada um deles e identificando as vantagens e limitações que possuem. Os resultados desta análise podem ser uma ferramenta de auxílio na escolha do algoritmo de rastreamento a ser utilizado quando do desenvolvimento de uma solução de reconstrução 3D, tendo como base o domínio do problema que se deseja atacar. Os três algoritmos analisados foram o SIFT, o KLT e outro Baseado em Similaridade. Foi desenvolvida uma ferramenta de reconstrução 3D baseada em SfM. Esta ferramenta foi utilizada para a coleta de resultados com o rastreamento sendo realizado com SIFT, KLT e Similaridade. Uma etapa importante deste processo foi a definição de um conjunto de métricas para a análise comparativa dos algoritmos. As características individuais de rastreamento de cada um deles trouxeram bons resultados em alguns dos cinco cenários utilizados. Porém, no geral, o rastreador que apresentou os melhores resultados foi o KLT. Uma análise detalhada sobre os resultados desses algoritmos quando empregados para reconstrução 3D é apresentada

Made available in DSpace on 2016-08-17T14:53:12Z (GMT). No. of bitstreams: 1 Denner Guilhon.pdf: 761750 bytes, checksum: 0100d830816d0600a5ff8aacd65531cb (MD5) Previous issue date: 2006-02-24 / The continuing demand for high performance and low cost electrocardiogram processing systems have required the elaboration of even more efficient and reliable ECG compression techniques. The objective of this work is to evaluate the performance of an electrocardiogram (ECG) compression algorithm based on independent components analysis (ICA). To each of the ECG signal we processed, using ICA, vectorial subspaces composed of its basis functions were obtained, for the signal can be expressed as a linear combination of them. The ECG signal was subdivided into m fixed length windows, and each of them was projected in the subspace, resulting in a vector w of coefficients for each window. A simple quantization process was performed over the m vectors w, according to defined levels of quantization, each one generating different levels of reconstruction error. It was observed that the storage of the coefficients implies the use of less space in memory in comparison to that one used by the corresponding windows of the electrocardiogram signal. The reconstruction error measure traditionally used, the percent root mean-square difference (PRD), was used into the evaluation of the algorithm. The results had been compared with those obtained using the Karhunen Lo´eve transform (KLT). / A demanda contınua de por sistemas de processamento de eletrocardiogramas de alto desempenho e baixo custo tem exigido a elaboração de técnicas de compressão de ECG cada vez mais eficientes e confiáveis. O objetivo deste trabalho é avaliar o desempenho de um algoritmo baseado em análise de componentes independentes (ICA) para a compressão de eletrocardiogramas (ECGs). Para cada um dos sinais de ECG utilizados foram obtidos, através de ICA, subespaços vetoriais construıdos a partir de suas funções base, pois o sinal pode ser expresso como uma combinação linear destas. O sinal de ECG foi subdividido em m janelas de comprimento fixo, e cada uma delas foi projetada no subespaço, resultando em um vetor w de coeficientes para cada janela. Um processo de quantização simples foi executado para os m vetores w, segundo nıveis de quantização definidos, cada um gerando diferentes nıveis de erro de reconstrução. Foi observado que o armazenamento dos coeficientes implica na utilização de um menor espaço em memória em comparação àquele utilizado pelas janelas correspondentes do sinal de eletrocardiograma. A medida tradicionalmente utilizada de erro de reconstrução, diferença média quadrática percentual (PRD), foi empregada para a avaliação do algoritmo. Os resultados foram comparados àqueles obtidos utilizando a transformada de Karhunen Loeve (KLT).

Although formative assessment is fundamental to educational theory and practices, it is a widely misunderstood term for most educators. This qualitative study defines formative assessment as short-cycle assessments in which teachers adapt their instruction to meet the learners‟ immediate needs. This study focused on the transformation of teachers‟ practices and their perspectives of the critical pedagogical principles necessary to enact The Keeping Learning on Track Program® (KLT™) in their classrooms and in teacher learning communities. The participants in this study included 21 formally trained KLT teachers at the St. Johnsbury School. Over a one year period, I observed in classrooms, attended all KLT teacher learning community (TLC) sessions, collected field notes, attended KLT trainings and presentations, and conducted individual and focus group interviews. The primary area of transformation included: the regulation of learning, beliefs and attitudes, accountability, shared leadership, systemic supports, motivation, classroom culture, and teacher practices.

INTRODUCTION AND AIM The prevalence of cardiovascular disease (CVD) has increased significantly in the black South African population in recent years. Early in the development of CVD, atherosclerotic plaques form in the vessel wall. When this plaque becomes unstable and ruptures, the coagulation cascade is activated and a blood clot forms. The function of this clot is to stop bleeding. However, it cannot remain in the vasculature indefinitely and has to be lysed again. The ability of the body to lyse clots can be measured with global fibrinolytic potential (GFP) assays and expressed as lysis time. Increased clot lysis time (CLT) has been shown to be significantly associated with various CVD risk factors and CVD events in Caucasian populations while very little information is available for other ethnicities. In this study we investigated plasma GFP and its relation to CVD risk factors in a large black African population. We also determined the effect of three polymorphisms in the promoter area of the plasminogen activator inhibitor-1 (PAI-1) gene on PAI-1act (activity) levels (a main determinant of CLT) and CLT, together with gene-environment interactions and the effect of urbanisation on these interactions. PARTICIPANTS AND METHODS Apparently healthy men and women between the ages of 35 and 65 years were recruited to take part in the South African arm of the Prospective Urban and Rural Epidemiology (PURE) study. Approximately 1000 rural and 1000 urban black African individuals participated. Data and samples were collected during a 12-week collection period in 2005 for cross-sectional analysis. RESULTS Increased PAI-1act levels, body mass index (BMI), glycosylated haemoglobin (HbA1c), triglycerides, fibrinogen concentration, C-reactive protein, female sex, positive HIV-status and the metabolic syndrome were all associated with prolonged CLTs, while increased habitual alcohol consumption was associated with shorter iv CLTs. Urban-rural differences for CLT existed in women only. This is likely due to the larger extent of rural-urban differences in other CVD risk factors observed in women compared to what was observed in men. Of the CVD risk factors measured, PAI-1 explained the largest proportion of the variance in CLT (27%). Owing to the important role PAI-1act plays in CLT, we investigated three polymorphisms in the PAI-1 gene promoter area (the 4G/5G polymorphism, the novel SNP C428T and SNP G429A (previously identified)), and the influence of these polymorphisms on PAI-1act levels and CLT. The frequency of the 5G allele was high (0.85) in comparison with previously reported literature. PAI-1act increased significantly across genotypes in the urban (5G/5G: 3.84 U/ml; 4G/5G: 4.85 U/ml; 4G/4G: 5.96 U/ml p=0.009) but not the rural subgroup, while CLT did not differ. We found significant interactions between the 4G/5G polymorphism and BMI, waist circumference and triglycerides in determining PAI-1act, and between the 4G/5G polymorphism and fibrinogen and fibrinogen gamma prime in determining CLT. Direct relationships with PAI-1act or CLT were not found for the C428T and G429A polymorphisms; they did, however, influence associations of other environmental factors with PAI-1act and CLT. Several of these interactions differed significantly between rural and urban subgroups, particularly in individuals harbouring the mutant alleles. CONCLUSION CLT associated with many of the same CVD risk factors described in the literature for Caucasian populations, but also with other risk factors. Rural-urban differences in CLT are dependent on the association of CLT with other CVD risk factors in the rural-urban setting. Genetic polymorphisms of the PAI-1 gene did not directly influence CLT, despite influencing PAI-1act. The main contributor to PAI-1act variance, however, was (central) obesity. The effect of the 4G/5G polymorphism on PAI-1act, as well as gene–environment interactions for the C428T and G429A genotypes in determining PAI-1act and CLT, were significantly influenced by urbanisation. / Thesis (PhD (Nutrition))--North-West University, Potchefstroom Campus, 2013.

INTRODUCTION AND AIM The prevalence of cardiovascular disease (CVD) has increased significantly in the black South African population in recent years. Early in the development of CVD, atherosclerotic plaques form in the vessel wall. When this plaque becomes unstable and ruptures, the coagulation cascade is activated and a blood clot forms. The function of this clot is to stop bleeding. However, it cannot remain in the vasculature indefinitely and has to be lysed again. The ability of the body to lyse clots can be measured with global fibrinolytic potential (GFP) assays and expressed as lysis time. Increased clot lysis time (CLT) has been shown to be significantly associated with various CVD risk factors and CVD events in Caucasian populations while very little information is available for other ethnicities. In this study we investigated plasma GFP and its relation to CVD risk factors in a large black African population. We also determined the effect of three polymorphisms in the promoter area of the plasminogen activator inhibitor-1 (PAI-1) gene on PAI-1act (activity) levels (a main determinant of CLT) and CLT, together with gene-environment interactions and the effect of urbanisation on these interactions. PARTICIPANTS AND METHODS Apparently healthy men and women between the ages of 35 and 65 years were recruited to take part in the South African arm of the Prospective Urban and Rural Epidemiology (PURE) study. Approximately 1000 rural and 1000 urban black African individuals participated. Data and samples were collected during a 12-week collection period in 2005 for cross-sectional analysis. RESULTS Increased PAI-1act levels, body mass index (BMI), glycosylated haemoglobin (HbA1c), triglycerides, fibrinogen concentration, C-reactive protein, female sex, positive HIV-status and the metabolic syndrome were all associated with prolonged CLTs, while increased habitual alcohol consumption was associated with shorter iv CLTs. Urban-rural differences for CLT existed in women only. This is likely due to the larger extent of rural-urban differences in other CVD risk factors observed in women compared to what was observed in men. Of the CVD risk factors measured, PAI-1 explained the largest proportion of the variance in CLT (27%). Owing to the important role PAI-1act plays in CLT, we investigated three polymorphisms in the PAI-1 gene promoter area (the 4G/5G polymorphism, the novel SNP C428T and SNP G429A (previously identified)), and the influence of these polymorphisms on PAI-1act levels and CLT. The frequency of the 5G allele was high (0.85) in comparison with previously reported literature. PAI-1act increased significantly across genotypes in the urban (5G/5G: 3.84 U/ml; 4G/5G: 4.85 U/ml; 4G/4G: 5.96 U/ml p=0.009) but not the rural subgroup, while CLT did not differ. We found significant interactions between the 4G/5G polymorphism and BMI, waist circumference and triglycerides in determining PAI-1act, and between the 4G/5G polymorphism and fibrinogen and fibrinogen gamma prime in determining CLT. Direct relationships with PAI-1act or CLT were not found for the C428T and G429A polymorphisms; they did, however, influence associations of other environmental factors with PAI-1act and CLT. Several of these interactions differed significantly between rural and urban subgroups, particularly in individuals harbouring the mutant alleles. CONCLUSION CLT associated with many of the same CVD risk factors described in the literature for Caucasian populations, but also with other risk factors. Rural-urban differences in CLT are dependent on the association of CLT with other CVD risk factors in the rural-urban setting. Genetic polymorphisms of the PAI-1 gene did not directly influence CLT, despite influencing PAI-1act. The main contributor to PAI-1act variance, however, was (central) obesity. The effect of the 4G/5G polymorphism on PAI-1act, as well as gene–environment interactions for the C428T and G429A genotypes in determining PAI-1act and CLT, were significantly influenced by urbanisation. / Thesis (PhD (Nutrition))--North-West University, Potchefstroom Campus, 2013.

GPGPU is a collective term for research involving general computation on graphics cards. A modern graphics card typically provides more than ten times the computational power of an ordinary PC processor. This is a result of the high demands for speed and image quality in computer games. This thesis investigates the possibility of exploiting this computational power for image processing purposes. Three well known methods where implemented on a graphics card: FFT (Fast Fourier Transform), KLT (Kanade Lucas Tomasi point tracking) and the generation of scale pyramids. All algorithms where successfully implemented and they are tree to ten times faster than correspondning optimized CPU implementation.