• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 102
  • 31
  • 30
  • 29
  • 17
  • 9
  • 7
  • 4
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 272
  • 40
  • 25
  • 24
  • 23
  • 22
  • 19
  • 17
  • 17
  • 17
  • 16
  • 15
  • 15
  • 14
  • 13
  • 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.
221

Spectrally-matched neutron detectors designed using computational adjoint S<sub>N for plug-in replacement of Helium-3

Walker, Scottie 20 September 2013 (has links)
Neutron radiation detectors are an integral part of the Department of Homeland Security (DHS) efforts to detect the illicit trafficking of radioactive or special nuclear materials into the U.S. In the past decade, the DHS has deployed a vast network of radiation detection systems at various key positions to prevent or to minimize the risk associated with the malevolent use of these materials. The greatest portion of this detection burden has been borne by systems equipped with 3He because of its highly desirable physical and nuclear properties. However, a dramatic increase in demand and dwindling supply, combined with a lack of oversight for the existing 3He stockpile has produced a critical shortage of this gas which has virtually eliminated its viability for detector applications. A number of research efforts have been undertaken to develop suitable 3He replacements; however, these studies have been solely targeted toward simple detection cases where the overall detection efficiency is the only concern. For these cases, an insertion of additional detectors or materials can produce reaction rates that are sufficient, because the neutron spectral response is essentially irrelevant. However, in applications such as safeguards, non-proliferation efforts, and material control and accountability programs (MC&A), a failure to use detectors that are spectrally matched to 3He can potentially produce dire consequences. This is because these more difficult detection scenarios are associated with fissile material assessments for 239Pu and other actinides and these analyses have almost universally been calibrated to an equivalent 3He response. In these instances, a “simple” detector or material addition approach is neither appropriate nor possible, due to influences resulting from the complex nature of neutron scattering in moderators, cross sections, gas pressure variations, geometries, and surrounding structural interference. These more challenging detection cases require a detailed computational transport analysis be performed for each specific application. A leveraged approach using adjoint transport computations that are validated by forward transport and Monte Carlo computations and laboratory measurements can address these more complex detection cases and this methodology was utilized in the execution of the research. The initial task was to establish the fidelity of a computational approach by executing radiation transport models for existing BF3 and 3He tubes and then comparing the modeling results to laboratory measurements made using these identical devices. Both tubes were 19.6 cm in height, 1-inch in diameter, and operated at 1 and 4 atm pressure respectively. The models were processed using a combination of forward Monte Carlo and forward and adjoint 3-D discrete ordinates (SN) transport methods. The computer codes MCNP5 and PENTRAN were used for all calculations of a nickel-shielded plutonium-beryllium (PuBe) source term that provided a neutron output spectra equivalent to that of weapons-grade plutonium (WGPu). Once the computational design approach was validated, the adjoint SN method was used to iteratively identify six distinct plug-in models that matched the neutron spectral response and reaction rate of a 1-inch diameter 3He tube with a length of 10 cm and operating at 4 atm pressure. The equivalent designs consist of large singular tubes and dual tubes containing BF3 gas, 10B linings, and/or 10B-loaded polyvinyl toluene (PVT). The reaction rate for each plug-in design was also verified using forward PENTRAN and MCNP5 calculations. In addition to the equivalent designs, the adjoint method also yielded various insights into neutron detector design that can lead to additional designs using a combination of different detector materials such as BF3/10B-loaded PVT, 10B-lined tubes/10B-loaded PVT, etc.
222

A estética da recepção contribuindo para o ensino de literatura-infantil : uma experiência com o conto A pequena vendedora de fósforos, de Hans Christian Andersen (1805-1875) /

Faria, Fernanda Cristina Ribeiro. January 2010 (has links)
Orientador: Ana Maria da Costa Santos Menin / Banca: Renata Junqueira de Souza / Banca: Henrique Silvestre Soares / Resumo: A presente pesquisa está vinculada ao programa de Pós-Graduação da Unesp de Presidente Prudente S/P e à linha de pesquisa Infância e Educação e gestada em um projeto maior denominado Literatura na escola: espaços e contextos. A realidade brasileira e portuguesa, coordenado pela professora Dra Renata Junqueira de Souza e realizado pelo Centro de Estudos em Leitura e Literatura Infantil e Juvenil - CELLIJ. O estudo partiu dos resultados calamitosos do Brasil em provas (Saresp, SAEB, PISA) que avaliam a competência leitora dos alunos comprovando o fato de as escolas não cumprirem com sua função primeira: ensinar a ler e escrever. Estudos têm mostrado que o hábito de leitura dos estudantes tem se tornado precário e insuficiente fato que, somado ao despreparo teórico e pedagógico dos professores relativamente ao ensino da literatura e à utilização do material literário, tem dificultado o trabalho com o livro literário no âmbito escolar, razão pela qual justifica-se esta investigação. A pesquisa teve por objetivo estudar as contribuições da Estética da Recepção para o ensino de literatura e para a formação do leitor, além de investigar a compreensão dos principais aspectos que levavam à aceitação, ou não, da obra e como ocorre a recepção literária. Para tanto, optou-se por um aporte teórico afinado com a teoria recepcional de Hans Robert Jauss, bem como a Metodologia Recepcional criada por Bordini e Aguiar e os Níveis de recepção literária de Hans Kügler. A pesquisa foi desenvolvida em uma escola municipal de Presidente Prudente e teve como público alvo alunos do 5º ano com os quais foi vivenciada uma prática pedagógica fundamentada na Estética... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This research is part of the graduate program at Department of Education in Unesp Presidente Prudente and related to the research topic concerning childhood and education, included in the Literature in the school: spaces and contexts, project intended to study the Brazilian and Portuguese realities. The project is coordinated by Professor Dr. Renata Junqueira de Souza and conducted by the Centre for studies in Reading and Literature for children and teens - CELLIJ. The study presented here was first motivated by unfortunate Brazilians' educational institutions results in regional, national and international tests (Saresp, SAEB, PISA) designed in order to evaluate the students' reading skills. Such results have been shown that the Brazilian schools teaching techniques do not meet to their primary function: teach students to write and read properly. There are some studies that have shown a lack between the students' reading habits and the required behaviour to meet a reading proficiency level. Moreover the theoretical and pedagogical teachers' background, generally, is not enough to suitably use the literary stuff with their students. Has a result, the literature learning process has been faced difficulties and the improvement need in this educational context comes out the importance of the research presented here. This research is purposed to study the Reception's Aesthetics contributions to the literature teaching goal and develop the students' comprehensive reading skills. In addition to that, it investigates the major issues related to acceptance of the literature. In order to reach these goals, our study draws on the receptional theory from Hans Robert Jauss, on Receptional Methodology created by Bordini and Aguiar and on Levels of literary reception from Hans Kügler. This research was developed in a school located in Presidente Prudente city... (Complete abstract click electronic access below) / Mestre
223

O efeito de jogos sucessivos nos parâmetros de desempenho físico de jovens jogadores de futebol / The effect of congested matches on physical performance measures of youth soccer players

Vinicius Miguel Zanetti 16 March 2018 (has links)
O objetivo da presente dissertação foi verificar o efeito da participação de jovens jogadores de futebol em competições com calendário congestionado (CC) nas medidas de desempenho físico, e comparar as acelerações (ACC), as desacelerações (DEC), a potência metabólica média (PM), distância total percorrida (DT) e distância percorrida em alta velocidade (DAV) em 24 jogadores de futebol juvenil (sub-15, n = 11 e sub-17, n = 13) expostos a campeonatos de CC e períodos regulares de calendário não congestionados (calendário regular; CR); como critério de retenção dos dados dos jogadores, adotou-se, a participação mínima de 75% do tempo total de jogo em cada partida. Adicionalmente as medidas de desempenho físico foram normalizadas pelo tempo de participação em minutos na partida. Foram analisados 10 jogos internacionais no formato de CC (5 para cada categoria), realizados durante 3 dias sucessivos, incluindo 2 dias com 2 jogos consecutivos jogados com intervalo de 4-5 horas; para estabelecer uma condição \"controle\", 10 jogos de CR, de cada categoria, foram analisados; os jogos de CR foram realizados com um intevalo de pelo menos 7 dias. Os jogadores usavam uma unidade GPS de 15 Hz com um acelerômetro triaxial de 100 Hz alocada em uma veste especial. Uma diferença classificada como digna de consideração (tamanho do efeito; TE> 0,20) entre CC e CR, foi observada para os parâmetros de desempenho físico ACC, DEC e PM, para sub-15 e sub-17, com valores mais elevados no CC. Enquanto que DT e DAV apresentaram valores superiores para CR, apenas para o sub-15. Contrariamente à hipótese levantada, os parâmetros de desempenho físico mostram que os jogadores juvenis de elite avaliados elevaram a intensidade do jogo quando participaram de torneio CC. Uma diminuição em ACC e DEC, do 1° tempo para o 2° tempo foi observada (sub-15 e sub-17) nos diferentes formatos de campeonato. No entanto, observou-se um aumento da PM do 1° tempo para o 2° tempo; com um aumento muito grande para ambas as categorias durante a CR; para o CC, a PM aumentou (1ª para a 2ª metade) para o sub-17, mas diminuiu para o sub-15. Os resultados do presente estudo, sugerem que os perfis de taxa de trabalho dos jogadores não são prejudicados no CC e que o desempenho físico aumentado nesse tipo de competição pode estar associado a uma estratégia de auto-regulação ou \"pacing\" da intensidade de realização das ações. Apesar das semelhanças para os dados de desempenho físico (sub-15 e sub-17), a PM para o sub-17 foi amplamente aumentada no CC (vs CR) em comparação com os valores de PM do sub-15; sugerindo assim, uma maior capacidade dos atletas, com um suposto nível mais elevado de treinamento (sub-17) em otimizar o desempenho físico neste tipo de competição. Estas informações podem servir como um meio alternativo e eficiente de representação do desempenho físico e auxiliar na organização de uma preparação específica de equipes participantes destes formatos de competições (CC); adicionalmente, os resultados indicam a importância de de considerar as medidas de ACC, DEC e PM na análise do desempenho físico de jovens jogadores, ao invés da utilização isolada de medidas relacionadas a DT e DAV / The aim of this study was to compare the physical performances in youth players during congested (CM) versus regular match (RM) schedules. The accelerations (ACC), decelerations (DEC), average metabolic power (MP), total distance covered (TD) and distance covered at high speed (HSD) were compared across congested match (CM; 10 international matches played over 3 successive days, including 2 days with 2 consecutive matches played with a 4-5 hr interval) and 10 regular non-congested match periods (RM), played with a 7-day interval between matches, in elite youth soccer players (U15, n=11; U17, n=13).; as criterion for retention of the players\' data, it was adopted, the minimum participation of 75% of the total match time of each game. In addition, all variables were normalized per min of on-field playing time. Each player wore a 15-Hz GPS unit coupled with a 100 Hz tri-axial accelerometer (SPI Elite, GPSports, Canberra, Australia A difference classified as worthy of consideration (effect size; ES > 0.20), between CM and RM, was observed for ACC, DEC and MP, for U15 and U17, with higher values in CM. While TD and HSD showed lower values for CM for u15. Contrary to the hypothesis, the relative values of the physical performance parameters were higher for CM. A decrease in ACC and DEC, from the 1st half to the 2nd half of the match was observed (U15 and U17) for both CM and RM. However, an increase in MP from the 1st half to the 2nd half of the match was observed; with a very large increase for both categories during the RM; during the CM, MP increased (1st half to the 2nd half) in the U7, but decreased in U15. The present findings suggest that the players work rate profiles are not impaired in CM and that the intensity of the match-play is increased in this type of competition, and might be associated to self-regulation or pacing strategy; despite the similarities for physical performance in U15 and U17), MP was largely increased in U17 during CM (vs CR) compared to U15; this result suggests that the higher the level of the conditioning, the greater the ability of the athlete in optimizing physical performance in this type of match schedule. This information can serve as an alternative and efficient means of representing physical performance and may help coaches to organize and monitor specific preparations of teams participating in these type of competitions (CM); additionally, the results indicate the importance of considering the ACC, DEC and MP measurements in the analysis of physical performance of young players, instead of using only measures related to total distance covered and distances covered at different speeds
224

Compressão de imagens utilizando recorrência de padrões multiescala com casamento lateral generalizado / Compression of images based on recurrent multiscale patterns with generalized side-match.

Abecassis, úrsula Vasconcelos 19 January 2006 (has links)
Made available in DSpace on 2015-04-11T14:03:06Z (GMT). No. of bitstreams: 1 Ursula Vasconcelos Abecassis.pdf: 1502428 bytes, checksum: 7ea813452788d8456776e20fe3c9ff1c (MD5) Previous issue date: 2006-01-19 / O algoritmo MMP (Multi-dimensional Multiscale Parser) é um esquema de compressão com perdas que tem como base o casamento aproximado de padrões multiescalas, no qual blocos de sinais de dimensões diferentes podem ser aproximados pelo seu dicionário. Tal aproximação é possível devido a uma transformação de escala que adapta as dimensões dos blocos, em versões dilatadas e contraídas, antes do casamento ser realizado. O MMP vem apresentando um bom desempenho em images com grande conteúdo de alta freqüência, mas em imagens suaves não apresentou resultados satisfatórios. Neste trabalho propõem-se uma melhoria da capacidade de compressão de imagens suaves, sem diminuir a qualidade de imagens mais complexas, tendo como base o algoritmo MMP, este algoritmo é chamado de GSM-MMP (Generalized Side-Match Multidimensional Multiscale Parser). O GSM-MMP realiza uma predição para a estruturação do dicionário de codificação baseada em semelhança com os três vizinhos do bloco atual que será codificado.
225

An Ontology for Match-Making in Plug and Play Business Software Platform

Mir, Muhammad Salman khan and Muhammad Arif Raza January 2008 (has links)
An innovation is the process of making improvements by introducing new idea in the form of product or service. In recent years, successful societies are shifting their focus towards the realization and acceptance of these new ideas. Plug and Play business software platform is the first step to transform these ideas into reality. The study presented in this thesis introduced that a new business idea contains specific business role and consists of a set of capabilities or needs and any one of them. Plug and play business software platform mainly consists of three major business processes that are required to run this platform those are; business match making process, negotiating process and collaboration process. This study analyzes the process of business match making in detail and introduce an ontology based business match making process which will find new businesses in a hierarchical fashion based on their specific business roles. Match making ontology consists of three processes i.e. information collection process which is used to collect and register information, extraction process which is an optional process to extract set of capabilities and needs if actor/innovator is unable to define its business capabilities and needs in information collection process and finally finding and ranking process which will find a set of potential collaborators and then will rank that set based on ranking parameters collected in information collection process from actor/innovator. This study also presents a technological model which will provide foundation to develop plug and play business software platform. This model identifies business processes of the platform and presents each business process as a separate loosely coupled software module. This model divides the platform into two layers; the upper layer is called PnP layer and consists of PnP Client Service, PnP Community Service, Finding and Ranking Service, Negotiating Service and Collaboration Service; lower layer is called kernel layer and consists of Security management Service, Operational management Services and Communication Service. Finally partially implemented prototype, test data and results will be used to visualize the presented concept.
226

Approximate Nearest Neighbour Field Computation and Applications

Avinash Ramakanth, S January 2014 (has links) (PDF)
Approximate Nearest-Neighbour Field (ANNF\ maps between two related images are commonly used by computer vision and graphics community for image editing, completion, retargetting and denoising. In this work we generalize ANNF computation to unrelated image pairs. For accurate ANNF map computation we propose Feature Match, in which the low-dimensional features approximate image patches along with global colour adaptation. Unlike existing approaches, the proposed algorithm does not assume any relation between image pairs and thus generalises ANNF maps to any unrelated image pairs. This generalization enables ANNF approach to handle a wider range of vision applications more efficiently. The following is a brief description of the applications developed using the proposed Feature Match framework. The first application addresses the problem of detecting the optic disk from retinal images. The combination of ANNF maps and salient properties of optic disks leads to an efficient optic disk detector that does not require tedious training or parameter tuning. The proposed approach is evaluated on many publicly available datasets and an average detection accuracy of 99% is achieved with computation time of 0.2s per image. The second application aims to super-resolve a given synthetic image using a single source image as dictionary, avoiding the expensive training involved in conventional approaches. In the third application, we make use of ANNF maps to accurately propagate labels across video for segmenting video objects. The proposed approach outperforms the state-of-the-art on the widely used benchmark SegTrack dataset. In the fourth application, ANNF maps obtained between two consecutive frames of video are enhanced for estimating sub-pixel accurate optical flow, a critical step in many vision applications. Finally a summary of the framework for various possible applications like image encryption, scene segmentation etc. is provided.
227

Video Compression Through Spatial Frequency Based Motion Estimation And Compensation

Menezes, Vinod 02 1900 (has links) (PDF)
No description available.
228

Data analytics and methods for improved feature selection and matching

May, Michael January 2012 (has links)
This work focuses on analysing and improving feature detection and matching. After creating an initial framework of study, four main areas of work are researched. These areas make up the main chapters within this thesis and focus on using the Scale Invariant Feature Transform (SIFT).The preliminary analysis of the SIFT investigates how this algorithm functions. Included is an analysis of the SIFT feature descriptor space and an investigation into the noise properties of the SIFT. It introduces a novel use of the a contrario methodology and shows the success of this method as a way of discriminating between images which are likely to contain corresponding regions from images which do not. Parameter analysis of the SIFT uses both parameter sweeps and genetic algorithms as an intelligent means of setting the SIFT parameters for different image types utilising a GPGPU implementation of SIFT. The results have demonstrated which parameters are more important when optimising the algorithm and the areas within the parameter space to focus on when tuning the values. A multi-exposure, High Dynamic Range (HDR), fusion features process has been developed where the SIFT image features are matched within high contrast scenes. Bracketed exposure images are analysed and features are extracted and combined from different images to create a set of features which describe a larger dynamic range. They are shown to reduce the effects of noise and artefacts that are introduced when extracting features from HDR images directly and have a superior image matching performance. The final area is the development of a novel, 3D-based, SIFT weighting technique which utilises the 3D data from a pair of stereo images to cluster and class matched SIFT features. Weightings are applied to the matches based on the 3D properties of the features and how they cluster in order to attempt to discriminate between correct and incorrect matches using the a contrario methodology. The results show that the technique provides a method for discriminating between correct and incorrect matches and that the a contrario methodology has potential for future investigation as a method for correct feature match prediction.
229

Modelagem estratégico-tática em esportes coletivos de invasão: aplicação ao basquetebol / Strategic and tactic modelling in invasion team sports: application to basketball

Leonardo Lamas Leandro Ribeiro 05 June 2012 (has links)
O objetivo do presente trabalho foi elaborar um modelo formal de descrição do jogo em esportes coletivos de invasão e instanciar o modelo a um esporte particular, o basquetebol, com a formalização de suas classes de comportamento ofensivos e defensivos. A estratégia foi modelada como um sistema dinâmico discreto. Este modelo tem como elemento lógico fundamental a regra de ação, que descreve as decisões de um jogador. As regras de ação também são usadas para a especificação da transformação de um estado e, consequentemente, da sequência de transformações de estados em um grafo representativo de uma estratégia. As propriedades estruturais, que são requisitos para uma estratégia eficiente, foram introduzidas na modelagem estratégica através de um conjunto de delimitadores (i.e., fases do jogo, tipos de conexões entre os nós por fase, regras de conexão, e regiões estratégicas), que especializam a definição da estratégia excluindo aquelas que não atendem aos requisitos dos delimitadores. O conjunto restante é denominado modelo da estratégia (ESTM). A formalização do ESTM apresentada neste trabalho estabelece uma metodologia para descrever, desenhar e avaliar a estratégia de uma equipe de um ECI. De maneira integrada à formalização da estratégia, a dinâmica do jogo foi modelada e a relação entre as estratégias desenhadas para duas equipes oponentes e a dinâmica do jogo foi apresentada. As estratégias atuam como bases de dados acessadas para subsidiar as decisões dos jogadores de uma equipe e permitir que eles atuem coletivamente durante as diferentes circunstâncias da oposição. A relação entre as estratégias desenhadas para duas equipes e a oposição no jogo entre estas equipes pode ser formalizada como um caso particular de sistema dinâmico, no qual dois sistemas dinâmicos discretos, representados pelas estratégias das equipes, e um sistema dinâmico contínuo, representado pelo jogo, são integrados por fluxos de controle e dados. Após formalizado o sistema dinâmico que representa a relação entre estratégia e oposição, no contexto do jogo, os elementos desse sistema foram decompostos, de forma hierárquica, levando em conta os principais módulos funcionais que compõem o fenômeno. Por fim, é apresentado o processo de validação das classes de comportamentos ofensivos e defensivos do jogo, constituídas por um conjunto limitado de dinâmicas individuais, grupais e coletivas, das quais a comissão técnica pode se valer para elaborar a estratégia da equipe, definir os conteúdos de treinamento, assim como selecionar aqules, dentre eles, cujo desempenho deverá ser avaliado no jogo. O modelo proposto constitui uma contribuição original à pedagogia dos esportes coletivos de invasão, tanto pelos avanços imediatos no entendimento das características estruturais desses esportes quanto pelos possíveis desdobramentos tecnológicos, que podem igualmente contribuir no processo de ensino-aprendizado nos mais diversos níveis competitivos / The aim of this study were: a) to develop a formal model to describe the game in invasion team sports (ITS) and instanciate the model to a particular sporte, the basketball; b) to validate classes of offensive and defensive behaviors in basketball. The strategy of ITS was modeled as a discrite dynamics system. This model has as a logical fundamental element named action rules, which describes the decisions of a player. The action rules are used to specify the transformations within a state and, consequently, the sequence of transformations of the states in a graph that representes the strategy of a team. The structural properties, pre-requisetes of an efficient strategy, were introduced in the model through a set of delimeters (i.e. game phases, types of connections between nodes per phase, rules of connections, and strategic regions) that specialize the the definition of strategy excluding those that do not posses the pre-requesites of the delimeters. The remaining set is defined as the strategy model. The strategy model formalized herein stablishes a metodology to describe, draw and evaluate the strategy of an IST team. Furthermore, match dynamics were modeled and integrated to the strategy model. The strategy constitute a data base which is assessed to support the team pleayers decisions and allow a collective behavior. The relationship between the strategy and the opposition in a match may be formalized as a particular familty of dynamic systems in which two discrete dynamical systems represented by the two strategies of the opposing teams, and a continuous dynamical system, represented by the match, are integrated by control and data fluxes. Once the model was constituted, its elements were hierarchicaly decomposed, considering the main functional models of the phenomenon. Finally, it is preseted the validation process of the possible offensive and defensive behaviors in a match, which are delimeted by a limited set of individual, group, and team dynamics. This set of behaviors may be used by the coaching staff to elaborate the team strategy, to define the training contentes, to determine how performance is going to be evaluated. The proposed model is an original contribution to the pedagogy of ITSs due to the increased understanding of the structural characteristics of these sports and the possible technological improvements that may be implemented in the teaching process at different competitive levels
230

Labour market integration of highly educated refugees in Sweden : Why are they mismatched?

Flemark, Sofia January 2021 (has links)
This paper investigates occupational mismatch of highly educated refugees in Sweden and aims to study what factors are impacting their labour market integration process. In contrast to the extensive number of quantitative reports based on registered data in the field, this research applies a qualitative approach by conducting interviews with the target group and incorporating a temporal aspect of the process. The results confirm existing theories such as human capital deficit, lack of social capital and signalling issues, but also indicates that contextual factors, being family demands and financial pressure, affect the process. An openness towards a change of field and lack of guidance from authorities emerged as factors for mismatch too. Lastly, feelings of stress and frustration seems to influence the process to a big extent which leads us to the conclusion that the labour market integration process of educated refugees is highly influenced by the aspect of time - and more specifically the lack of it.

Page generated in 0.0515 seconds