Made available in DSpace on 2014-12-17T14:55:16Z (GMT). No. of bitstreams: 1 RafaelBG_TESE.pdf: 2529249 bytes, checksum: b16afb21de612f10dcfa5acb69028967 (MD5) Previous issue date: 2013-08-02 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Visual attention is a very important task in autonomous robotics, but, because of its complexity, the processing time required is significant. We propose an architecture for feature selection using foveated images that is guided by visual attention tasks and that reduces the processing time required to perform these tasks. Our system can be applied in bottom-up or top-down visual attention. The foveated model determines which scales are to be used on the feature extraction algorithm. The system is able to discard features that are not extremely necessary for the tasks, thus, reducing the processing time. If the fovea is correctly placed, then it is possible to reduce the processing time without compromising the quality of the tasks outputs. The distance of the fovea from the object is also analyzed. If the visual system loses the tracking in top-down attention, basic strategies of fovea placement can be applied. Experiments have shown that it is possible to reduce up to 60% the processing time with this approach. To validate the method, we tested it with the feature algorithm known as Speeded Up Robust Features (SURF), one of the most efficient approaches for feature extraction. With the proposed architecture, we can accomplish real time requirements of robotics vision, mainly to be applied in autonomous robotics / A aten??o visual ? uma importante tarefa em rob?tica aut?noma, mas devido ? sua complexidade, o tempo de processamento necess?rio ? significativo. Prop?e-se uma arquitetura para sele??o de features usando imagens foveadas que ? guiada por tarefas envolvendo aten??o visual e que reduz o tempo de processamento para realizar tais tarefas. O sistema proposto pode ser aplicado para aten??o bottom-up ou top-down. O modelo de foveamento determina quais escalas devem ser utilizadas no algoritmo de extra??o de features. O sistema ? capaz de descartar features que n?o s?o essenciais para a realiza??o da tarefa e, dessa forma, reduz o tempo de processamento. Se a f?vea ? corretamente posicionada, ent?o ? poss?vel reduzir o tempo de processamento sem comprometer o desempenho da tarefa. A dist?ncia da f?vea para o objeto tamb?m ? analisada. Caso o sistema visual perca o tracking na aten??o top-down, estrat?gias b?sicas de reposicionamento da f?vea podem ser aplicadas. Experimentos demonstram que ? poss?vel reduzir em at? 60% o tempo de processamento com essa abordagem. Para validar o m?todo proposto, s?o realizados testes com o algoritmo de extra??o de features SURF, um dos mais eficientes existentes. Com a arquitetura proposta para sele??o de features, ? poss?vel cumprir requisitos de um sistema de vis?o em tempo-real com poss?veis aplica??es na ?rea de rob?tica

Parmi les maladies affectant les pommes, la moisissure bleue causée par Penicillium expansum est une préoccupation majeure. Elle cause des pertes de rendement et de qualité dues également à la production de mycotoxines telles que la patuline (PAT) et la citrinine (CIT). La PAT est la plus alarmante en raison de ses propriétés cytotoxiques, génotoxiques et immunosuppressives.L'Union européenne (UE) a établi des réglementations spécifiques pour protéger la santé des consommateurs et des niveaux maximaux de 50 g / kg sont fixés pour les jus de fruits et les produits dérivés, 25 g / kg pour les purées de pommes et les compotes et 10 g / kg pour les aliments destinés aux bébés et aux jeunes enfants. En dépit de ces mesures, la PAT continue à être présente dans les aliments et / ou les boissons commerciaux, dépassant parfois les limites maximales. Des recherches supplémentaires sont par conséquent nécessaires pour minimiser la contamination des produits alimentaires par cette mycotoxine et son champignon producteur. Bien que la plupart des études sur P. expansum soient essentiellement centrées sur la PAT, le génomede ce champignon présente d'autres clusters de métabolites secondaires (SM) prédits dont certains peuvent être associés à des métabolites potentiellement toxiques. Afin de contrôler la synthèse de SM, l'étude des facteurs de transcription globaux régulant leur production est essentielle. Dans une première partie, le gène veA, appartenant à la famille des protéines du complexe velvet, a été caractérisé et son impact sur le développement du champignon, sa virulence et son métabolisme secondaire a été élucidé. La délétion de ce gène a conduit à une réduction de la production de PAT et de CIT et à une diminution de l'expression de leurs clusters de gènes. VeA a également un impact global sur le métabolisme secondaire, puisque 15 des 35gènes de structure présentent une régulation différentielle sur les milieux testés. Dans une deuxième partie, l’influence de l’acide ascorbique (AA) sur la concentration de PAT dans le jus de pomme trouble a été étudiée à la fois en laboratoire et en milieu semi-industriel. Une méthodologie analytique séparant la PAT et d'autres composés générés au cours de la réaction aété optimisée. Les conditions optimales d'action de l’AA sur la PAT ont été analysées. De plus,nous avons identifié des produits de dégradation moins toxiques que la PAT et résultant du traitement par l’AA. Pour conclure, cette thèse se rattache à la gestion des risques de la PAT dans le secteur des fruits ; elle apporte des connaissances et des améliorations significatives tant sur le plan fondamental que sur le plan pratique. Ces avancées résident principalement dans la description d'une souche mutée de P. expansum moins toxique que celle naturellement retrouvée dans la nature, et décrivant un additif alimentaire améliorant les qualités de nombreux produits transformés et diminuant la concentration de PAT en générant des composés moins toxiques. / Among diseases affecting apples, blue mould caused by Penicillium expansum is a major concern. It causes yield and quality losses, as well as food safety issues due to the production of mycotoxins such as patulin (PAT) and citrinin (CIT). PAT is the most worrying one and has cytotoxic, genotoxic and immunosuppressive properties. The European Union (EU) has established specific regulations to protect the consumer’s health and maximum levels of PAT of 5 g/kg is set for fruit juices and derived products, 25 g/kg for apple purees and compotes and 10g/kg for food intended for babies and young children. However, PAT is still found in commercial food and/or beverage products, sometimes exceeding the maximum limits and more research is needed to minimize contamination of food products by this mycotoxin and its fungus. Even though most studies on P. expansum have focused on PAT itself, the genome of this fungus exhibits other predicted secondary metabolite (SM) clusters, some of which may be associated with potentially toxic metabolites. In order to control the synthesis of SMs, the study of global transcription factors regulating their production is essential. In a first part, the veA gene, belonging to the velvet family, was characterised and its impact on the development of the fungus, its virulence and its secondary metabolism was elucidated. The disruption of this gene led to the failure in PAT and CIT production and a decrease in the expression of their gene cluster. It also revealed a global impact on the secondary metabolism, as 15 of 35 backbone genes showed differential regulation on the media tested. In a second part, the influence of ascorbic acid (AA) on the concentration of PAT in cloudy apple juice was studied on both lab and semi-industrial scale. An analytical methodology separating PAT and other compounds generated during the reaction was optimized. Optimal conditions of action of AA on PAT were studied. In addition, degradation products less toxic than PAT and resulting from AA treatment were identified. To conclude, this thesis is part of the risk management of PAT in the fruit sector; it provides significant improvements at both fundamental and practical levels. These advances are mainly characterized by the description of a mutated strain of P. expansum that is less toxic than that naturally occurring in nature, and the description of a food additive that improves numerous products qualities and affects PAT concentration, thusgenerating less toxic compounds

Made available in DSpace on 2014-12-17T14:55:40Z (GMT). No. of bitstreams: 1 RafaelBG.pdf: 2393943 bytes, checksum: 45924e13c3c73c1eaaf09dcc478bd70e (MD5) Previous issue date: 2009-08-07 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / We propose a new approach to reduction and abstraction of visual information for robotics vision applications. Basically, we propose to use a multi-resolution representation in combination with a moving fovea for reducing the amount of information from an image. We introduce the mathematical formalization of the moving fovea approach and mapping functions that help to use this model. Two indexes (resolution and cost) are proposed that can be useful to choose the proposed model variables. With this new theoretical approach, it is possible to apply several filters, to calculate disparity and to obtain motion analysis in real time (less than 33ms to process an image pair at a notebook AMD Turion Dual Core 2GHz). As the main result, most of time, the moving fovea allows the robot not to perform physical motion of its robotics devices to keep a possible region of interest visible in both images. We validate the proposed model with experimental results / N?s propomos uma nova abordagem para reduzir e abstrair informa??es visuais para aplica??es de vis?o rob?tica. Basicamente, usamos uma representa??o emmulti-resolu??o em combina??o com uma f?vea m?vel para reduzir a quantidade de informa??es de uma imagem. Apresentamos a formaliza??o matem?tica do modelo em conjunto com fun??es de mapeamento que auxiliam na utiliza??o do modelo. Propomos dois ?ndices (resolu??o e custo) que visam auxiliar na escolha das vari?veis do modelo proposto. Com essa nova abordagem te?rica, ? poss?vel aplicar diversos filtros, calcular disparidade est?reo e obter an?lise de movimento em tempo real (menos de 33ms para processar um par de imagens em um notebook AMD Turion Dual Core 2GHz). Como principal resultado, na maior parte do tempo, a f?vea m?vel permite ao rob? n?o realizar movimenta??o f?sica de seus dispositivos rob?ticos para manter uma poss?vel regi?o de interesse vis?vel nas duas imagens. Validamos o modelo proposto com resultados experimentais

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No contexto atual dos mercados globalizados, as empresas enfrentam uma competicao cada vez mais complexa na obtencao de capital. Para atrai-lo, elas precisam oferecer um retorno que remunere o risco assumido pelos investidores, ou seja, gerar valor. A Gestao Baseada no Valor defende a maximizacao de riqueza dos acionistas como a meta principal da organizacao. No Brasil, essa abordagem tem sido adotada de forma mais intensa na ultima decada, tornando evidente a necessidade de monitorar o valor da firma nessa economia. Nesse contexto, o objetivo deste estudo foi identificar os principais direcionadores de valor das empresas de capital aberto nao financeiras brasileiras, representadas pelas companhias com acoes negociadas na Bolsa de Valores de Sao Paulo (BM&FBOVESPA), no periodo de 2000 a 2009. Para isso, foram avaliados quais indicadores financeiros estavam mais relacionados a geracao de valor, representada pelo Valor Economico Agregado (VEA), de forma a serem considerados direcionadores desse em cada setor economico. As tecnicas estatísticas utilizadas para esse proposito foram: correlacao, teste t para diferenca de medias entre as empresas com VEA positivo e negativo, regressao multipla, regressao em painel e regressão logistica. Um dos principais resultados encontrados foi que pelo menos dois tercos dos indicadores financeiros utilizados para analise de empresas nao explicam a geracao de valor. Considerando o universo pesquisado, os indicadores financeiros significativamente relacionados a geracao de valor foram: retorno sobre o patrimonio liquido (ROE), retorno sobre o ativo (ROA), spread do acionista, margem bruta, margem liquida e giro do ativo, todos com coeficiente positivo, ou seja, com relacao direta com o VEA. Alem disso, na analise dos setores economicos, por suas caracteristicas especificas, foram encontradas divergencias entre os indicadores financeiros considerados direcionadores de valor. Em relacao ao desempenho das empresas no periodo de analise, observou-se que a maioria delas destruiu valor, ja que apenas 30% obtiveram valor economico agregado anual positivo. Porem, nao ha uniformidade entre os setores, pois as porcentagens medias variaram de 6,7% (setor textil) a 66,7% (setor de petroleo e gas). Outra contribuicao deste trabalho foi a avaliacao das diferencas na geracao de valor das empresas brasileiras antes e apos a crise do subprime. Como resultado tem-se que, embora o ano de 2009 tenha sido o segundo pior nesse quesito, nao foi encontrada diferenca significativa, no conjunto, entre os periodos antes e depois da crise, apesar das divergencias identificadas entre os setores. Esta pesquisa inova pela sua amplitude, ao utilizar um significativo numero de indicadores financeiros (33), que refletem o resultado de estrategias da empresa ligadas a estrutura de capital, rentabilidade, liquidez, operacao e investimento e, tambem, uma ampla base de dados (345 empresas, totalizando 2.205 relatorios anuais), abrangendo dez anos de analise em quinze setores economicos. Assim, espera-se que os resultados contribuam para subsidiar a tomada de decisao nas organizacoes, utilizando a abordagem da Gestao Baseada no Valor, bem como para auxiliar na selecao e monitoramento das empresas pelos investidores. / In the current context of globalized markets, the enterprises face a competition more and more complex in the capital obtainment. To attract it, they need to offer a return that rewards the risk taken by the investors, in other words, create value. The Value Based Management (VBM) defends the shareholders wealth maximization as the main goal of the firm. In Brazil, this approach has been adopted more intensively in the last decade, becoming evident the need of monitoring the business value in this economy. In this context, the objective of this study was to identify the main value drivers of non-financial publicly traded Brazilian companies, represented by the ones with shares traded in the Sao Paulo Stock Exchange (BM&FBOVESPA), in the period from 2000 to 2009. For this purpose, it was evaluated which financial indicators were more associated to the value creation, represented by the Economic Value Added (EVAR), in a way that they could be considered value drivers in each economic sector. The statistical techniques used to obtain the results were: correlation, test t for mean differences between the firms with EVAR positive and negative, multiple regression, panel regression and logit model. One of the main results obtained was that at least two thirds of the financial indicators used for company analysis don\'t explain the value creation. Considering the universe studied, the financial indicators significantly related to the value creation were: return on equity (ROE), return on assets (ROA), shareholder spread, gross margin, net margin and asset turnover, all of them with positive coefficient, what means that they have direct relation with EVAR. Furthermore, in the analysis of the economic sectors, because of their specific features, it was found differences between the financial indicators considered value drivers. In relation to the companies\' performance in the period analyzed, it was observed that most of them destroyed value, since only 30% obtained positive annual economic value added. However, there is no uniformity between the sectors, because the average percentages varied from 6.7% (textile sector) to 66.7% (oil and gas sector). Another contribution of this assignment was the analysis of the differences in the Brazilian companies\' value creation before and after the subprime crisis. As a result, despite the fact that the year of 2009 had been the second worst in this criterion, it was found no significant difference, considering the whole sample, between the periods before and after the crisis. However, divergences were identified between the sectors. This research innovates for its extent, using a significant number of financial indicators (33), which reflect the result of the firm strategies connected to capital structure, profitability, liquidity, operation and investment, besides a wide database (345 companies, totalizing 2,205 annual reports), covering ten years of analysis in fifteen economic sectors. Therefore, it is expected that the results contribute to subsidize the decision making in the organizations, using the approach of Value Based Management, as well as to help the selection and monitoring of the firms by the investors.

No contexto atual dos mercados globalizados, as empresas enfrentam uma competicao cada vez mais complexa na obtencao de capital. Para atrai-lo, elas precisam oferecer um retorno que remunere o risco assumido pelos investidores, ou seja, gerar valor. A Gestao Baseada no Valor defende a maximizacao de riqueza dos acionistas como a meta principal da organizacao. No Brasil, essa abordagem tem sido adotada de forma mais intensa na ultima decada, tornando evidente a necessidade de monitorar o valor da firma nessa economia. Nesse contexto, o objetivo deste estudo foi identificar os principais direcionadores de valor das empresas de capital aberto nao financeiras brasileiras, representadas pelas companhias com acoes negociadas na Bolsa de Valores de Sao Paulo (BM&FBOVESPA), no periodo de 2000 a 2009. Para isso, foram avaliados quais indicadores financeiros estavam mais relacionados a geracao de valor, representada pelo Valor Economico Agregado (VEA), de forma a serem considerados direcionadores desse em cada setor economico. As tecnicas estatísticas utilizadas para esse proposito foram: correlacao, teste t para diferenca de medias entre as empresas com VEA positivo e negativo, regressao multipla, regressao em painel e regressão logistica. Um dos principais resultados encontrados foi que pelo menos dois tercos dos indicadores financeiros utilizados para analise de empresas nao explicam a geracao de valor. Considerando o universo pesquisado, os indicadores financeiros significativamente relacionados a geracao de valor foram: retorno sobre o patrimonio liquido (ROE), retorno sobre o ativo (ROA), spread do acionista, margem bruta, margem liquida e giro do ativo, todos com coeficiente positivo, ou seja, com relacao direta com o VEA. Alem disso, na analise dos setores economicos, por suas caracteristicas especificas, foram encontradas divergencias entre os indicadores financeiros considerados direcionadores de valor. Em relacao ao desempenho das empresas no periodo de analise, observou-se que a maioria delas destruiu valor, ja que apenas 30% obtiveram valor economico agregado anual positivo. Porem, nao ha uniformidade entre os setores, pois as porcentagens medias variaram de 6,7% (setor textil) a 66,7% (setor de petroleo e gas). Outra contribuicao deste trabalho foi a avaliacao das diferencas na geracao de valor das empresas brasileiras antes e apos a crise do subprime. Como resultado tem-se que, embora o ano de 2009 tenha sido o segundo pior nesse quesito, nao foi encontrada diferenca significativa, no conjunto, entre os periodos antes e depois da crise, apesar das divergencias identificadas entre os setores. Esta pesquisa inova pela sua amplitude, ao utilizar um significativo numero de indicadores financeiros (33), que refletem o resultado de estrategias da empresa ligadas a estrutura de capital, rentabilidade, liquidez, operacao e investimento e, tambem, uma ampla base de dados (345 empresas, totalizando 2.205 relatorios anuais), abrangendo dez anos de analise em quinze setores economicos. Assim, espera-se que os resultados contribuam para subsidiar a tomada de decisao nas organizacoes, utilizando a abordagem da Gestao Baseada no Valor, bem como para auxiliar na selecao e monitoramento das empresas pelos investidores. / In the current context of globalized markets, the enterprises face a competition more and more complex in the capital obtainment. To attract it, they need to offer a return that rewards the risk taken by the investors, in other words, create value. The Value Based Management (VBM) defends the shareholders wealth maximization as the main goal of the firm. In Brazil, this approach has been adopted more intensively in the last decade, becoming evident the need of monitoring the business value in this economy. In this context, the objective of this study was to identify the main value drivers of non-financial publicly traded Brazilian companies, represented by the ones with shares traded in the Sao Paulo Stock Exchange (BM&FBOVESPA), in the period from 2000 to 2009. For this purpose, it was evaluated which financial indicators were more associated to the value creation, represented by the Economic Value Added (EVAR), in a way that they could be considered value drivers in each economic sector. The statistical techniques used to obtain the results were: correlation, test t for mean differences between the firms with EVAR positive and negative, multiple regression, panel regression and logit model. One of the main results obtained was that at least two thirds of the financial indicators used for company analysis don\'t explain the value creation. Considering the universe studied, the financial indicators significantly related to the value creation were: return on equity (ROE), return on assets (ROA), shareholder spread, gross margin, net margin and asset turnover, all of them with positive coefficient, what means that they have direct relation with EVAR. Furthermore, in the analysis of the economic sectors, because of their specific features, it was found differences between the financial indicators considered value drivers. In relation to the companies\' performance in the period analyzed, it was observed that most of them destroyed value, since only 30% obtained positive annual economic value added. However, there is no uniformity between the sectors, because the average percentages varied from 6.7% (textile sector) to 66.7% (oil and gas sector). Another contribution of this assignment was the analysis of the differences in the Brazilian companies\' value creation before and after the subprime crisis. As a result, despite the fact that the year of 2009 had been the second worst in this criterion, it was found no significant difference, considering the whole sample, between the periods before and after the crisis. However, divergences were identified between the sectors. This research innovates for its extent, using a significant number of financial indicators (33), which reflect the result of the firm strategies connected to capital structure, profitability, liquidity, operation and investment, besides a wide database (345 companies, totalizing 2,205 annual reports), covering ten years of analysis in fifteen economic sectors. Therefore, it is expected that the results contribute to subsidize the decision making in the organizations, using the approach of Value Based Management, as well as to help the selection and monitoring of the firms by the investors.

The economic value creation is something that affects all companies, that is why, it is crucial to establish , for which purpose, there are a variety of procedures. Among which, especially the method of economic value added (EVA), which can compare the yield of investment to its financial cost. This methodology is very useful, but its definition does not distinguish EVA from the business effects with EVA generated results, so in this article we propose a new way to determine the EVA that allows differentiation and the EVA distinction created by many results achievable by the company. Finally, an explanatory case it is presented to demonstrate if the new proposal it is applicable or not. / La creación de valor económico es el norte que mueve a toda empresa, por lo tanto, es crucial establecer su valor económico, para lo cual existe una diversidad de procedimientos. Entre todos ellos, destaca el método del valor económico añadido (VEA), el cual tiene la virtud de comparar el rendimiento de la inversión con su costo de financiamiento. La propuesta metodológica es de mucha utilidad, pero en su delimitación no permite distinguir el VEA proveniente de los efectos del negocio con los VEA generados por otros resultados, por lo que en este artículo se plantea una nueva forma de determinar el VEA que permite diferenciar y distinguir los VEA creados por los diversos resultados que podría obtener la empresa. Por último, se presenta un caso explicativo que permite demostrar la aplicabilidad de la nueva propuesta.