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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.
41

Avaliação de Impactos Ambientais e Alimentares de Plantas Geneticamente Modificadas (PGM): uma proposta metodológica. / A methodological proposal of Environmental and Food Impact Assessment of Genetically Modified Plants (GMP).

Cremonezi, Simone Marchini Naves 25 August 2009 (has links)
Diante do atual cenário de expansão dos plantios geneticamente modificados e da carência de metodologias no Brasil para prever os seus impactos foi desenvolvimento um método intitulado Impactos-PGM para Avaliação de Impactos Ambientais e Alimentares de Plantas Geneticamente Modificadas utilizando como ferramenta um Software de aplicação geral adequado e modificado com esta finalidade. Para tanto, foi inicialmente realizado o levantamento de indicadores de impactos a partir da literatura. Esta consulta foi realizada pela aplicação de questionário de acordo com a técnica delphi. Posteriormente, os especialistas foram entrevistados presencialmente: foram apresentados os indicadores mais representativos para a avaliação dos impactos das PGMs, possibilitando a elaboração do método Impactos-PGM por meio da adequação do Software Impactos. / In face of the current expansion scenario of genetically modified crops and the lack of methodologies in Brazil to predict its impacts, the present work has been proposed to develop a method entitled Impactos-GMP for \"Food and Environmental Assessment of Genetically Modified Plants (GMPs) Impacts using as tool a software of general application suitable and modified for this purpose. Thus, the survey was first conducted by identifying impact indicators from the literature. This survey was held through the application of a questionnaire according to the delphi technique. Subsequently, the researchers were interviewed in person to whom were presented the most representative indicators for GMPs assessing impacts, enabling the development of the method Impactos-GMP with the adequacy of the iImpacts software.
42

Statistical Modeling of High-Dimensional Nonlinear Systems: A Projection Pursuit Solution

Swinson, Michael D. 28 November 2005 (has links)
Despite recent advances in statistics, artificial neural network theory, and machine learning, nonlinear function estimation in high-dimensional space remains a nontrivial problem. As the response surface becomes more complicated and the dimensions of the input data increase, the dreaded "curse of dimensionality" takes hold, rendering the best of function approximation methods ineffective. This thesis takes a novel approach to solving the high-dimensional function estimation problem. In this work, we propose and develop two distinct parametric projection pursuit learning networks with wide-ranging applicability. Included in this work is a discussion of the choice of basis functions used as well as a description of the optimization schemes utilized to find the parameters that enable each network to best approximate a response surface. The essence of these new modeling methodologies is to approximate functions via the superposition of a series of piecewise one-dimensional models that are fit to specific directions, called projection directions. The key to the effectiveness of each model lies in its ability to find efficient projections for reducing the dimensionality of the input space to best fit an underlying response surface. Moreover, each method is capable of effectively selecting appropriate projections from the input data in the presence of relatively high levels of noise. This is accomplished by rigorously examining the theoretical conditions for approximating each solution space and taking full advantage of the principles of optimization to construct a pair of algorithms, each capable of effectively modeling high-dimensional nonlinear response surfaces to a higher degree of accuracy than previously possible.
43

Mercado preditivo: um método de previsão baseado no conhecimento coletivo / Prediction market: a forecasting method based on the collective knowledge

Ivan Roberto Ferraz 08 December 2015 (has links)
Mercado Preditivo (MP) é uma ferramenta que utiliza o mecanismo de preço de mercado para agregar informações dispersas em um grande grupo de pessoas, visando à geração de previsões sobre assuntos de interesse. Trata-se de um método de baixo custo, capaz de gerar previsões de forma contínua e que não exige amostras probabilísticas. Há diversas aplicações para esses mercados, sendo que uma das principais é o prognóstico de resultados eleitorais. Este estudo analisou evidências empíricas da eficácia de um Mercado Preditivo no Brasil, criado para fazer previsões sobre os resultados das eleições gerais do ano de 2014, sobre indicadores econômicos e sobre os resultados de jogos do Campeonato Brasileiro de futebol. A pesquisa teve dois grandes objetivos: i) desenvolver e avaliar o desempenho de um MP no contexto brasileiro, comparando suas previsões em relação a métodos alternativos; ii) explicar o que motiva as pessoas a participarem do MP, especialmente quando há pouca ou nenhuma interação entre os participantes e quando as transações são realizadas com uma moeda virtual. O estudo foi viabilizado por meio da criação da Bolsa de Previsões (BPrev), um MP online que funcionou por 61 dias, entre setembro e novembro de 2014, e que esteve aberto à participação de qualquer usuário da Internet no Brasil. Os 147 participantes registrados na BPrev efetuaram um total de 1.612 transações, sendo 760 no tema eleições, 270 em economia e 582 em futebol. Também foram utilizados dois questionários online para coletar dados demográficos e percepções dos usuários. O primeiro foi aplicado aos potenciais participantes antes do lançamento da BPrev (302 respostas válidas) e o segundo foi aplicado apenas aos usuários registrados, após dois meses de experiência de uso da ferramenta (71 respostas válidas). Com relação ao primeiro objetivo, os resultados sugerem que Mercados Preditivos são viáveis no contexto brasileiro. No tema eleições, o erro absoluto médio das previsões do MP na véspera do pleito foi de 3,33 pontos percentuais, enquanto o das pesquisas de opinião foi de 3,31. Considerando todo o período em que o MP esteve em operação, o desempenho dos dois métodos também foi parecido (erro absoluto médio de 4,20 pontos percentuais para o MP e de 4,09 para as pesquisas). Constatou-se também que os preços dos contratos não são um simples reflexo dos resultados das pesquisas, o que indica que o mercado é capaz de agregar informações de diferentes fontes. Há potencial para o uso de MPs em eleições brasileiras, principalmente como complemento às metodologias de previsão mais tradicionais. Todavia, algumas limitações da ferramenta e possíveis restrições legais podem dificultar sua adoção. No tema economia, os erros foram ligeiramente maiores do que os obtidos com métodos alternativos. Logo, um MP aberto ao público geral, como foi o caso da BPrev, mostrou-se mais indicado para previsões eleitorais do que para previsões econômicas. Já no tema futebol, as previsões do MP foram melhores do que o critério do acaso, mas não houve diferença significante em relação a outro método de previsão baseado na análise estatística de dados históricos. No que diz respeito ao segundo objetivo, a análise da participação no MP aponta que motivações intrínsecas são mais importantes para explicar o uso do que motivações extrínsecas. Em ordem decrescente de relevância, os principais fatores que influenciam a adoção inicial da ferramenta são: prazer percebido, aprendizado percebido, utilidade percebida, interesse pelo tema das previsões, facilidade de uso percebida, altruísmo percebido e recompensa percebida. Os indivíduos com melhor desempenho no mercado são mais propensos a continuar participando. Isso sugere que, com o passar do tempo, o nível médio de habilidade dos participantes tende a crescer, tornando as previsões do MP cada vez melhores. Os resultados também indicam que a prática de incluir questões de entretenimento para incentivar a participação em outros temas é pouco eficaz. Diante de todas as conclusões, o MP revelou-se como potencial técnica de previsão em variados campos de investigação. / Prediction Market (PM) is a tool which uses the market price mechanism to aggregate information scattered in a large group of people, aiming at generating predictions about matters of interest. It is a low cost method, able to generate forecasts continuously and it does not require random samples. There are several applications for these markets and one of the main ones is the prognosis of election outcomes. This study analyzed empirical evidences on the effectiveness of Prediction Markets in Brazil, regarding forecasts about the outcomes of the general elections in the year of 2014, about economic indicators and about the results of the Brazilian Championship soccer games. The research had two main purposes: i) to develop and evaluate the performance of PMs in the Brazilian context, comparing their predictions to the alternative methods; ii) to explain what motivates people´s participation in PMs, especially when there is little or no interaction among participants and when the trades are made with a virtual currency (play-money). The study was made feasible by means of the creation of a prediction exchange named Bolsa de Previsões (BPrev), an online marketplace which operated for 61 days, from September to November, 2014, being open to the participation of any Brazilian Internet user. The 147 participants enrolled in BPrev made a total of 1,612 trades, with 760 on the election markets, 270 on economy and 582 on soccer. Two online surveys were also used to collect demographic data and users´ perceptions. The first one was applied to potential participants before BPrev launching (302 valid answers) and the second was applied only to the registered users after two-month experience in tool using (71 valid answers). Regarding the first purpose, the results suggest Prediction Markets to be feasible in the Brazilian context. On the election markets, the mean absolute error of PM predictions on the eve of the elections was of 3.33 percentage points whereas the one of the polls was of 3.31. Considering the whole period in which BPrev was running, the performance of both methods was also similar (PM mean absolute error of 4.20 percentage points and poll´s 4.09). Contract prices were also found as not being a simple reflection of poll results, indicating that the market is capable to aggregate information from different sources. There is scope for the use of PMs in Brazilian elections, mainly as a complement of the most traditional forecasting methodologies. Nevertheless, some tool limitations and legal restrictions may hinder their adoption. On markets about economic indicators, the errors were slightly higher than those obtained by alternative methods. Therefore, a PM open to general public, as in the case of BPrev, showed as being more suitable to electoral predictions than to economic ones. Yet, on soccer markets, PM predictions were better than the criterion of chance although there had not been significant difference in relation to other forecasting method based on the statistical analysis of historical data. As far as the second purpose is concerned, the analysis of people´s participation in PMs points out intrinsic motivations being more important in explaining their use than extrinsic motivations. In relevance descending order, the principal factors that influenced tool´s initial adoption are: perceived enjoyment, perceived learning, perceived usefulness, interest in the theme of predictions, perceived ease of use, perceived altruism and perceived reward. Individuals with better performance in the market are more inclined to continue participating. This suggests that, over time, participants´ average skill level tends to increase, making PM forecasts better and better. Results also indicate that the practice of creating entertainment markets to encourage participation in other subjects is ineffective. Ratifying all the conclusions, PM showed as being a prediction potential technique in a variety of research fields.
44

Combined decision making with multiple agents

Simpson, Edwin Daniel January 2014 (has links)
In a wide range of applications, decisions must be made by combining information from multiple agents with varying levels of trust and expertise. For example, citizen science involves large numbers of human volunteers with differing skills, while disaster management requires aggregating information from multiple people and devices to make timely decisions. This thesis introduces efficient and scalable Bayesian inference for decision combination, allowing us to fuse the responses of multiple agents in large, real-world problems and account for the agents’ unreliability in a principled manner. As the behaviour of individual agents can change significantly, for example if agents move in a physical space or learn to perform an analysis task, this work proposes a novel combination method that accounts for these time variations in a fully Bayesian manner using a dynamic generalised linear model. This approach can also be used to augment agents’ responses with continuous feature data, thus permitting decision-making when agents’ responses are in limited supply. Working with information inferred using the proposed Bayesian techniques, an information-theoretic approach is developed for choosing optimal pairs of tasks and agents. This approach is demonstrated by an algorithm that maintains a trustworthy pool of workers and enables efficient learning by selecting informative tasks. The novel methods developed here are compared theoretically and empirically to a range of existing decision combination methods, using both simulated and real data. The results show that the methodology proposed in this thesis improves accuracy and computational efficiency over alternative approaches, and allows for insights to be determined into the behavioural groupings of agents.
45

Avaliação de Impactos Ambientais e Alimentares de Plantas Geneticamente Modificadas (PGM): uma proposta metodológica. / A methodological proposal of Environmental and Food Impact Assessment of Genetically Modified Plants (GMP).

Simone Marchini Naves Cremonezi 25 August 2009 (has links)
Diante do atual cenário de expansão dos plantios geneticamente modificados e da carência de metodologias no Brasil para prever os seus impactos foi desenvolvimento um método intitulado Impactos-PGM para Avaliação de Impactos Ambientais e Alimentares de Plantas Geneticamente Modificadas utilizando como ferramenta um Software de aplicação geral adequado e modificado com esta finalidade. Para tanto, foi inicialmente realizado o levantamento de indicadores de impactos a partir da literatura. Esta consulta foi realizada pela aplicação de questionário de acordo com a técnica delphi. Posteriormente, os especialistas foram entrevistados presencialmente: foram apresentados os indicadores mais representativos para a avaliação dos impactos das PGMs, possibilitando a elaboração do método Impactos-PGM por meio da adequação do Software Impactos. / In face of the current expansion scenario of genetically modified crops and the lack of methodologies in Brazil to predict its impacts, the present work has been proposed to develop a method entitled Impactos-GMP for \"Food and Environmental Assessment of Genetically Modified Plants (GMPs) Impacts using as tool a software of general application suitable and modified for this purpose. Thus, the survey was first conducted by identifying impact indicators from the literature. This survey was held through the application of a questionnaire according to the delphi technique. Subsequently, the researchers were interviewed in person to whom were presented the most representative indicators for GMPs assessing impacts, enabling the development of the method Impactos-GMP with the adequacy of the iImpacts software.
46

Utvecklares delaktighet i beslut : En studie om utvecklares upplevelse av delaktighet i beslut inom långsiktiga projekt

Munoz, Roberto, Sylve, Alexander January 2021 (has links)
This paper examines developers' experience of participation in decisions through agile system development methods in long-term projects. Participation is meant as an opportunity for developers to influence and realize decisions in their work through independence and freedom. The research question reads as follows: "How are developers' perceived participation in decisions during long-term projects affected?". Through five qualitative interviews with developers from an international military company, institutional logics are used as a complementary theoretical framework and analytical support. Tensions between a professional logic and a management logic are indicated to be the two main logics that pressure developers' perceived participation in decisions over a long-term period. By combining development methods over time within long-term projects, daily follow-up varies and developers' perceived participation in decisions may be affected. Partial deliveries promote developers' perceived participation in decisions because developers can receive ongoing feedback on their decisions. Developers are required to make constant considerations in their decisions in order to achieve flexibility and meet requirements, but are limited by access to information due to defense-secrecy. / Uppsatsen undersöker utvecklares upplevelse av delaktighet i beslut genom agila systemutvecklingsmetoder inom långsiktiga projekt. Delaktighet avses som möjlighet för utvecklare att genom självständighet och frihet påverka samt realisera beslut i sin arbetssituation. Forskningsfrågan som tagits fram lyder enligt följande: “Hur påverkas utvecklares upplevelse av delaktighet i beslut under långsiktiga projekt?”. Genom fem kvalitativa intervjuer med utvecklare från ett militärt internationellt företag används institutionella logiker som ett kompletterande teoretiskt ramverk och analysstöd. Spänningar mellan en professionslogik och en management-logik indikeras vara de två huvudsakliga logiker som sätter press på utvecklares upplevelse av delaktighet i beslut under en lång tidshorisont. Genom att systemutvecklingsmetoder blandas över tid inom långsiktiga projekt varieras daglig uppföljning och utvecklares upplevelse av delaktighet i beslut kan komma att påverkas. Delleveranser främjar utvecklares upplevelse av delaktighet i beslut eftersom utvecklare kan få löpande återkoppling på sina beslut. Utvecklare erfordras göra ständiga avvägningar i sina beslut för att uppnå flexibilitet och möta krav, men begränsas av tillgång till information till följd av försvarssekretess.
47

DYNAMICS OF LARGE ARRAY MICRO/NANO RESONATORS

Borra, Chaitanya 15 July 2020 (has links)
No description available.
48

Contribuições do pensamento sistêmico no design contemporâneo / The contribution of systemic thought in the contemporary design

Pereira, Fabiano Virginio 06 June 2014 (has links)
A investigação a partir da perspectiva histórica torna possível identificar que o design, como área de estudo, vem promovendo constantes reflexões sobre as configurações das soluções presentes nas rotinas sociais. No entanto, em função do aumento da condição participativa social baseada nas atuais tecnologias de informação em rede, pode-se afirmar que as soluções disponíveis atualmente e suas relações com o campo do design passaram também por um processo de ampliação de sua abrangência sistêmica. Neste sentido, o objetivo deste trabalho é desenvolver um estudo sobre as aproximações entre o pensamento sistêmico e o campo do design no contexto atual, a partir da análise das características que se apresentam como demandas sociais emergentes no mundo complexo em que vivemos. Este estudo busca identificar as dimensões e abordagens do pensamento sistêmico orientado pelo design como interface para solução de problemas em múltiplos cenários. Como organização, este trabalho foi dividido em três capítulos que apresentam: estudo sobre o contexto contemporâneo e as demandas para soluções em design, as aproximações entre o pensamento sistêmico e o campo do design e por fim as relações entre design sistêmico e inovação social. Desta forma, o capítulo 1 estuda os atributos emergentes que caracterizam as relações entre as necessidades sociais atuais e o campo do design, a produção da informação em rede e as dimensões cognitivas e afetivas manifestadas pelos dispositivos tecnológicos de uso diário, além da cultura da mobilidade e a relação entre sua manifestação e as soluções de design. O capítulo 2 é dedicado à análise das relações entre as práxis da concepção sistêmica e do design, ao estudo sobre a perspectiva histórica do design, às propriedades do pensamento sistêmico e às aproximações entre a concepção sistêmica e o campo do design. O capítulo 3 consiste na apresentação de abordagens acerca dos envolvidos e impactados pela manifestação do design sistêmico, na identificação das relações entre a \"Inovação sociocultural\" e a concepção sistêmica no design, como processo de facilitação para soluções convergentes. Como conclusão, considerações que visam contribuir para a reflexão sobre a abrangência e os contornos acerca da manifestação do design sistêmico na contemporaneidade. / From the study of the historical perspective, it is possible to identify that the design fields is promoting constantly new approaches to settings solutions for the social routines. However, with the increase of social based on participatory condition of network information technologies, it can be stated that the solutions currently available and their relations with the design field, also passed by a process of systemic expansion of its range. In this sense, the objective of this study is to develop a study on the approximations between the systemic thought and the design field in the current context, from the analysis of the characteristics that present themselves as social demands emerging in the complex world that we live. This study seeks to identify the dimensions and approaches of systemic thought guided by design as interface for troubleshooting in multiple scenarios. As organization, this work was divided into three chapters that feature: study about the contemporary context and its demands for design solutions, the approximations between the systemic thought and the design field and finally the relationship between systemic design and social innovation. In this way, chapter 1 studies the emerging attributes that characterize the relations between the current social needs and the field of design, the production of the network information and the cognitive and affective dimensions expressed by technological devices for daily use, in addition to the culture of mobility and the relationship between its manifestation and the design solutions. Chapter 2 is dedicated to analyzing of relations between the praxis of systemic conception and design, this study on the historical perspective of the design, the properties of systemic thought and the approximations between the systemic conception and design field. Chapter 3 consists of the presentation of approaches about the involved and impacted by the manifestation of systemic design, on the identification of relations between \"Socialcultural Innovation\" and the systemic conception at design, as a process of facilitation for converged solutions. As a conclusion, this work presents considerations that aim to contribute to the reflection on the comprehensiveness and contours about the manifestation of systemic design in nowadays.
49

Contribuições do pensamento sistêmico no design contemporâneo / The contribution of systemic thought in the contemporary design

Fabiano Virginio Pereira 06 June 2014 (has links)
A investigação a partir da perspectiva histórica torna possível identificar que o design, como área de estudo, vem promovendo constantes reflexões sobre as configurações das soluções presentes nas rotinas sociais. No entanto, em função do aumento da condição participativa social baseada nas atuais tecnologias de informação em rede, pode-se afirmar que as soluções disponíveis atualmente e suas relações com o campo do design passaram também por um processo de ampliação de sua abrangência sistêmica. Neste sentido, o objetivo deste trabalho é desenvolver um estudo sobre as aproximações entre o pensamento sistêmico e o campo do design no contexto atual, a partir da análise das características que se apresentam como demandas sociais emergentes no mundo complexo em que vivemos. Este estudo busca identificar as dimensões e abordagens do pensamento sistêmico orientado pelo design como interface para solução de problemas em múltiplos cenários. Como organização, este trabalho foi dividido em três capítulos que apresentam: estudo sobre o contexto contemporâneo e as demandas para soluções em design, as aproximações entre o pensamento sistêmico e o campo do design e por fim as relações entre design sistêmico e inovação social. Desta forma, o capítulo 1 estuda os atributos emergentes que caracterizam as relações entre as necessidades sociais atuais e o campo do design, a produção da informação em rede e as dimensões cognitivas e afetivas manifestadas pelos dispositivos tecnológicos de uso diário, além da cultura da mobilidade e a relação entre sua manifestação e as soluções de design. O capítulo 2 é dedicado à análise das relações entre as práxis da concepção sistêmica e do design, ao estudo sobre a perspectiva histórica do design, às propriedades do pensamento sistêmico e às aproximações entre a concepção sistêmica e o campo do design. O capítulo 3 consiste na apresentação de abordagens acerca dos envolvidos e impactados pela manifestação do design sistêmico, na identificação das relações entre a \"Inovação sociocultural\" e a concepção sistêmica no design, como processo de facilitação para soluções convergentes. Como conclusão, considerações que visam contribuir para a reflexão sobre a abrangência e os contornos acerca da manifestação do design sistêmico na contemporaneidade. / From the study of the historical perspective, it is possible to identify that the design fields is promoting constantly new approaches to settings solutions for the social routines. However, with the increase of social based on participatory condition of network information technologies, it can be stated that the solutions currently available and their relations with the design field, also passed by a process of systemic expansion of its range. In this sense, the objective of this study is to develop a study on the approximations between the systemic thought and the design field in the current context, from the analysis of the characteristics that present themselves as social demands emerging in the complex world that we live. This study seeks to identify the dimensions and approaches of systemic thought guided by design as interface for troubleshooting in multiple scenarios. As organization, this work was divided into three chapters that feature: study about the contemporary context and its demands for design solutions, the approximations between the systemic thought and the design field and finally the relationship between systemic design and social innovation. In this way, chapter 1 studies the emerging attributes that characterize the relations between the current social needs and the field of design, the production of the network information and the cognitive and affective dimensions expressed by technological devices for daily use, in addition to the culture of mobility and the relationship between its manifestation and the design solutions. Chapter 2 is dedicated to analyzing of relations between the praxis of systemic conception and design, this study on the historical perspective of the design, the properties of systemic thought and the approximations between the systemic conception and design field. Chapter 3 consists of the presentation of approaches about the involved and impacted by the manifestation of systemic design, on the identification of relations between \"Socialcultural Innovation\" and the systemic conception at design, as a process of facilitation for converged solutions. As a conclusion, this work presents considerations that aim to contribute to the reflection on the comprehensiveness and contours about the manifestation of systemic design in nowadays.
50

Model Reduction for Piezo-Mechanical Systems using Balanced Truncation

Uddin, Mohammad Monir 29 April 2011 (has links)
Today in the scientific and technological world, physical and artificial processes are often described by mathematical models which can be used for simulation, optimization or control. As the mathematical models get more detailed and different coupling effects are required to include, usually the dimension of these models become very large. Such large-scale systems lead to large memory requirements and computational complexity. To handle these large models efficiently in simulation, control or optimization model order reduction (MOR) is essential. The fundamental idea of model order reduction is to approximate a large-scale model by a reduced model of lower state space dimension that has the same (to the largest possible extent) input-output behavior as the original system. Recently, the system-theoretic method Balanced Truncation (BT) which was believed to be applicable only to moderately sized problems, has been adapted to really large-scale problems. Moreover, it also has been extended to so-called descriptor systems, i.e., systems whose dynamics obey differential-algebraic equations. In this thesis, a BT algorithm is developed for MOR of index-1 descriptor systems based on several papers from the literature. It is then applied to the setting of a piezo-mechanical system. The algorithm is verified by real-world data describing micro-mechanical piezo-actuators. The whole algorithm works for sparse descriptor form of the system. The piezo-mechanical original system is a second order index-1 descriptor system, where mass, damping, stiffness, input and output matrices are highly sparse. Several techniques are introduced to reduce the system into a first order index-1 descriptor system by preserving the sparsity pattern of the original models. Several numerical experiments are used to illustrate the efficiency of the algorithm.

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