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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Seleção genômica ampla no melhoramento vegetal / Genome wide selection in plant breeding

Resende Júnior, Márcio Fernando Ribeiro de 16 April 2010 (has links)
Made available in DSpace on 2015-03-26T13:42:16Z (GMT). No. of bitstreams: 1 texto completo.pdf: 750903 bytes, checksum: 9c754e0205ce36c2c3ced3e42d923e0d (MD5) Previous issue date: 2010-04-16 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The Genome Wide selection was proposed in 2001 to predict the phenotype values based in molecular markers information. In a previus step, the effect of each of each marker in controlling the genetic variance is estimated. This technology has already been used in animals, however, no report of its use was made for plants. This work aimed to study the impact of GWS, first in a simulated dataset, then in two Eucalyptus populations. Besides that, on the simulated data, it was compared the efficiency of using dominant markers versus the use of codominant ones. The simulation generated one population controlled by many genes (polygenic) and one population with olligogenic control. There were different situations of linkage disequilibrium among the marker and the QTL, different number of markers controlling the trait and heritabilities of 20, 30 and 40%. It was evaluated the prediction ability and the accuracy of the GWS. The results of accuracy were high, which turn in to a selection gain of up to 500% in the selection dataset and the use dominant markers at higher densities is more efficient than the use of dominant markers with lower densities. The Euvalyptus populations were genotyped for total height, diameter at breast height (DBH) and Pilodyn. The values of accuracy were 0,67 for height and 0,69 for DBH in the first population and ,53, 0,62, and 0,53 for total height, DBH and Pilodyn respectively. Those result turn in to a selection gain that varied from 430% to 723% with a reduction of 7 years in the breeding cycle. This showed significant results and gave evidences that the use of GWS in plants is possible to improve the way plant breeding is actually performed. / A seleção genômica ampla (GWS) foi idealizada no ano de 2001 como forma de predizer o fenótipo futuro de uma população baseado em informações de marcadores moleculares, cujos efeitos genéticos aditivos, que estes explicam, já foram previamente estimados. Esta tecnologia já é pesquisada e integrada aos programas de melhoramento animal. Embora em plantas nenhum trabalho com dados reais tenha sido descrito, a GWS tem grandes perspectivas de utilização também no melhoramento genético vegetal, o que pode permitir melhores acurácias e seleção precoce. O objetivo deste trabalho foi, em um primeiro momento, fornecer subsídios para melhor entender a seleção genômica ampla e fazer uma comparação de sua utilização com marcadores dominantes e codominantes. Em uma segunda etapa, a aplicação dessa tecnologia foi então proposta em Eucalyptus e seu impacto foi avaliado no melhoramento florestal. Foram simuladas uma característica de controle oligogênico e outra controlada por muitos genes em diferentes situações de desequilíbrio de ligação com os marcadores. Em cada característica, o número de locos que controlava o caracter foi estabelecido entre 100, 200 e 400 e as herdabilidades entre 20%, 30% e 40%. Foi avaliada a correlação dos valores fenotípicos observados com os valores fenotípicos preditos via informação de marcadores e a acuáracia de seleção. A partir das estimativas de acurácia, calculou-se também o ganho de seleção por unidade de tempo comparado com a seleção fenotípica. Os resultados das simulações demonstraram altos valores de acurácias que proporcionaram ganhos de até 500% caso o tempo do ciclo de geração seja reduzido. Observou-se que se o número de marcadores dominantes disponíveis foi superior ao número de marcadores codominantes, essa maior densidade proporciona acurácias maiores. A segunda etapa do trabalho foi realizada em duas populações de Eucalipto utilizando marcadores dominantes DArTs e avaliando as características Altura total, Diâmetro a Altura do Peito (DAP) e penetração do Pilody. As acurácias máximas obtidas foram de 0,67 para Altura e 0,69 para DAP em uma população, e de 0,53, 0,62, e 0,53 para Altura, DAP e Pilodyn, respectivamente, na segunda população. Estes valores proporcionaram ganhos que variaram entre 430% e 723% caso o ciclo de geração seja reduzido em 7 anos, situação possível no melhoramento de Eucalipto. Este trabalho demonstrou resultados animadores e o uso GWS se mostrou factível em plantas nas simulações e no conjunto de dados reais.
12

Identification and Development of a Model of Railway Track Dynamic Behaviour

Steffens, David Martyn January 2005 (has links)
The research presented in this thesis has identified and developed a sophisticated computer model for the analysis of railway track dynamic behaviour to be used by the Rail Cooperative Research Centre for Railway Engineering and Technologies (Rail CRC) in Australia. To be competitive railway track owners need to extract as much performance as possible from their asset without serviceability or catastrophic failure. Railway track designers therefore need to develop more knowledge of the static and dynamic loadings that track may be subjected to in its lifetime. This would be best undertaken using computer modelling capable of quantifying the effects of train speed, traffic mix, wheel impact loading and distribution of vehicle loads into the track. A comprehensive set of criteria for the selection of a model of track dynamic behaviour was developed. An international review of state-of-the-art models which represented the railway track structure under the loading of a passing train was undertaken. The models' capabilities were assessed and a number of potential models identified. A benchmark test was initiated to compare current models available throughout the international railway research community. This unique benchmark test engaged six researchers to compare their railway track models using a set of theoretical vehicle and track data. The benchmark results showed that significantly different results may be obtained by models, depending on the assumptions of the user in representing a particular track scenario. Differing complexities and modelling methods, the number of different input parameters required and the representation of the irregularities in the wheel and rail all have effect on the results produced. As a result of these initiatives, the DARTS (Dynamic Analysis of Rail Track Structures) computer model was chosen for use by the Rail CRC. A user-friendly interface was created for DARTS by the writer, which was readily interpretable by railway design engineers. At the time of writing, DARTS was found to be suitable for detailed investigations planned by the Rail CRC for future research and was provided for use through an Intellectual Property agreement with its author.
13

The Effects of Depleted Self-Regulation on Skilled Task Performance

McEwan, Desmond 04 1900 (has links)
<p>The purpose of this study was to examine the effects of depleted self-regulation on skillful task performance. Participants completed a baseline dart-tossing task (20 tosses), and were instructed to toss as quickly and as close to the bulls-eye as possible when a particular cue light flashed. Participants then underwent a self-regulatory depleting (experimental) or a non-depleting (control) manipulation before completing a second round of dart tossing. Measures of accuracy, reaction time, and myoelectrical activity of the biceps and triceps were collected along with self-report measures of psychological resilience and trait self-control.</p> <p>As hypothesized, participants in the experimental condition had poorer mean accuracy at round two than control condition participants, as well as a significant decline in accuracy from round one to round two. These effects were moderated by trait self-control; experimental group participants with higher trait self-control were more accurate in round two than experimental group participants with lower trait self-control. Experimental group participants also demonstrated poorer consistency in accuracy compared to control group participants at round two, and a significant deterioration in consistency from round one to round two. The only significant finding regarding reaction time was that consistency improved significantly for the control group but not for the experimental group.</p> <p>The results of this study provide evidence that ego depletion effects occur for skill-based physical task performance, especially in regards to accuracy. These findings provide further support for the utility of the limited strength model and suggest that self-regulatory depletion can impact performance on skill-based physical tasks.</p> / Master of Science in Kinesiology
14

Perceived body cathexis and garment fit and style proportion problems of petite women

Huckabay, Dabney A. 06 October 2009 (has links)
The purposes of this study were to determine if petite women have a positive or negative body cathexis, to see if petite women perceive themselves as having garment fit and style proportion problems, and to explore the relationships between these variables and selected demographic information. The sample was made up of 132 Spiegel catalog shoppers. The sample ranged in height from 4'9" to 5'6" with 670/0 being 5'2" and under. Results for the 5'2" and under were looked at separately. The total sample was satisfied with all the body cathexis variables except for thighs and stomach. The 5'2" and under petites were satisfied with all the variables except four, leg length, hips, stomach, and height. Most of the fit problems were associated with length. The majority of the sample 5'2" and under reported available clothing too long in the sleeves, skirts, pants, and crotch depth. Most of the style proportion problems reported in this research were associated with the length of garments and garment components. The miscellaneous items that created the most problems for this sample were pocket location and dart location. These problems were more predominate for the 5'2" and under sample. Over 50% of 5'2" and under sample reported problems with lengths and pocket location. And at least 25% of them reported problems in 22 other areas. There did not appear to be any relationship between the perceived garment fit variables and style proportion problems and the body cathexis variables, nor between the demographics and the perceived garment fit and the style proportion problems The majority of the sample shopped at mail order stores (catalogs) and department stores. The department most often shopped was the petite department. The majority of the women had their ready-to-wear clothing altered to achieve a better fit and solve their style proportion problems. The majority (74%) was not satisfied with the current petite clothing available. The most conclusive data in this study pertained to the implication of problems with dart location and pocket placement. The garment proportion in relation to darts and pocket placement were inappropriate for some of these petite subjects. / Master of Science
15

Struktury trie pro zpracování rozsáhlých textových dat / Trie Structures for Large Text Data Processing

Rajčok, Andrej January 2016 (has links)
This study analyzes natural language processing with emphasis on morphological analysis of inflective languages and systems for named entity recognition. It analyzes effective pattern matching in dictionary by using succint structures and then analyzes practical implementation of succint structures. It describes design and implementation of named entity recognition system and morphological analyzer and compares and test their speed and effectiveness.

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