Les Interface Cerveau-Machine (ICM) ont appliquées avec succès aussi bien dans le domain clinique que pour l'amélioration de la vie quotidienne de patients avec des handicaps. En tant que composante essentielle, le module de traitement du signal détermine nettement la performance d'un système ICM. Nous nous consacrons à améliorer les stratégies de traitement du signal du point de vue de l'apprentissage de la machine. Tout d'abord, nous avons développé un algorithme basé sur les SVM transductifs couplés aux noyaux multiples afin d'intégrer différentes vues des données (vue statistique ou une vue géométrique) dans le processus d'apprentissage. Deuxièmement, nous avons proposé une version en ligne de l'apprentissage multi-noyaux dans le cas supervisé. Les résultats expérimentaux montrent de meilleures performances par rapport aux approches classiques. De plus, l'algorithme proposé permet de sélectionner automatiquement les canaux de signaux EEG utiles grâce à l'apprentissage multi-noyaux. Dans la dernière partie, nous nous sommes attaqué à l'amélioration du module de traitement du signal au-delà des algorithmes d'apprentissage auomatique eux-mêmes. En analysant les données ICM hors-ligne, nous avons d'abord confirmé qu'un modèle de classification simple peut également obtenir des performances statisfaisantes en effectuant une sélection de caractéristiques (et.ou de canaux). Nous avons ensuite conçu un système émotionnel ICM par en tenant compte de l'état émotionnel de l'utilisateur. Sur la base des données de l'EEG obtenus avec différents états émotionnels, c'est-à-dire, positives, négatives et neutre émotions, nous avons finalement prouvé que l'émotion affecter les performances ICM en utilisant des tests statisques. Cette partie de la thèse propose des bases pour réaliser des ICM plus adaptées aux utilisateurs.

Les Interfaces Cerveau-Machines (ICMs) visent à établir un moyen de communication direct entre le cerveau humain et un système électronique. Si d'importantes avancées ont d'ores et déjà été réalisées depuis une vingtaine d'années dans le domaine, les systèmes existants s'avèrent lents et fastidieux, imposant aux utilisateurs le moment auquel ils doivent envoyer leur commande (systèmes synchrones). Nos travaux se sont concentrés sur le développement de systèmes asynchrones basés sur l'électroencéphalographie (EEG) : ce n'est pas l'ordinateur qui impose le moment de réalisation de la tâche mentale mais le sujet qui a la possibilité d'envoyer sa commande lorsque qu'il le désire. Ceci impose que le système soit capable d'analyser en temps réel l'activité cérébrale du sujet et de reconnaître la tâche mentale recherchée parmi les activités cérébrales mesurées. Nos travaux proposent des méthodes pour les problématiques suivantes : • permettre à l'utilisateur d'envoyer sa commande lorsqu'il le désire ; • augmenter les capacités du système à reconnaître correctement une tâche mentale ; • rendre le système robuste à certains changements qui peuvent s'opérer lors de l'utilisation du système, i.e., adapter le système aux possibles changements du sujet dans la manière dont celui-ci accomplit sa tâche mentale. Les méthodes proposées utilisent de manière conjointe les caractéristiques spatiales (zones cérébrales impliquées), fréquentielles (bandes de fréquences) et temporelles (succession des activations) des tâches mentales afin de pallier le faible rapport signal sur interférences. Différents jeux de données sont utilisés afin de valider ces approches.

Le claquage diélectrique constitue une limitation importante dans l'utilisation des matériaux isolants sous haute-tension puisqu'il conduit à la fusion et la sublimation locales du matériau. La microstructure (taille de grains, phase intergranulaire) joue un rôle important sur la capacité du matériau à résister à ce phénomène catastrophique. En effet, les interfaces entre les différentes phases constituent des sites potentiels de piégeage pour les charges. L'optimisation de la rigidité diélectrique passe donc nécessairement par le contrôle des paramètres microstructuraux. Ainsi, est montré qu'en maîtrisant les conditions d'élaboration (taux d'ajouts, granulométrie de la poudre et cycle thermique), il est possible de contrôler la densité (par la taille moyenne de grains) mais également la nature (par la cristallisation ou non de l'anorthite) des joints de grains. L'étude de l'influence de ces deux paramètres ainsi que de la température sur les propriétés de transport et de piégeage des charges a été réalisée par les méthode ICM et SEMME. Les résultats ainsi obtenus, interprétés à la lumière de la simulation numérique du comportement d'un isolant soumis à une irradiation électronique, ont permis de mettre en évidence des comportements, et les microstructures correspondantes, favorables à une bonne tenue au claquage diélectrique en fonction de la température considérée. Ainsi, à température ambiante une densité d'interfaces élevée (taille de grains faible et phase vitreuse cristallisée) permet au matériau de piéger durablement une quantité importante de charges, ce qui conduit à une rigidité diélectrique élevée. En revanche, à plus haute température, la présence de pièges de faible profondeur (phase intergranulaire vitreuse) favorise la diffusion des charges et permet de retarder le claquage.

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós-Graduação em Oceanografia Física, Química e Geológica, Instituto de Oceanografia, 2008. / Submitted by Cristiane Silva (cristiane_gomides@hotmail.com) on 2013-03-12T12:27:06Z No. of bitstreams: 1 2008_tiago_gandra.pdf: 4024866 bytes, checksum: 3540cf3f3ea76e36028fd0985ef4ab5e (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2013-06-17T18:40:54Z (GMT) No. of bitstreams: 1 2008_tiago_gandra.pdf: 4024866 bytes, checksum: 3540cf3f3ea76e36028fd0985ef4ab5e (MD5) / Made available in DSpace on 2013-06-17T18:40:54Z (GMT). No. of bitstreams: 1 2008_tiago_gandra.pdf: 4024866 bytes, checksum: 3540cf3f3ea76e36028fd0985ef4ab5e (MD5) Previous issue date: 2008 / Este trabalho trata de dois instrumentos de suporte à gestão ambiental previstos no Plano Nacional de Gerenciamento Costeiro (PNGC) - o Sistema de Informações Geográficas Costeiras (SIGERCO) e o Zoneamento Ecológico-Econômico Costeiro (ZEEC) - utilizando o Município de Rio Grande (RS) como estudo de caso. Ele consiste na organização e integração de dados no SIGERCO de maneira que este possa auxiliar no desenvolvimento de uma metodologia simples, flexível e replicável para a elaboração do ZEEC. Existe uma forte demanda para que os municípios costeiros elaborem seus ZEEC, mas as experiências anteriores utilizaram metodologias e resultados que não seguem os critérios e classes definidos pelo PNGC. Para a construção do ZEEC é necessária a definição da Unidade Ambiental de Gestão (UAG’s) adequada. Para tal, foram compilados diversos tipos de divisão territorial já realizadas na região. Para a definição das UAG’s foi escolhida a abordagem geomorfológica, baseando-se em experiências anteriores registradas na bibliografia. Os critérios definidos pelo PNGC para o ZEEC são subjetivos, possibilitando uma enorme gama de zoneamentos distintos, dependente dos pesos atribuídos a cada critério e da definição de quebras de classe. Foram avaliados e comparados quatro experimentos de ZEEC segundo as diretrizes do PNGC, bem como um ZEEC obtido com os critérios utilizados em Santa Catarina e o zoneamento aprovado no Plano Ambiental Municipal (PLAM) de Rio Grande. O SIGERCO produzido para o município pode representar um salto na compreensão e difusão de conhecimentos científicos para a tomada de decisões, desde que seja disponibilizado via internet e esteja em constante ampliação e atualização. A metodologia proposta nesta dissertação exige poucos dados para a elaboração do ZEEC (geomorfologia, vegetação, usos dos solos e censo do IBGE), o que possibilita a rápida elaboração ou adequação dos ZEEC’s. A subjetividade da metodologia proposta deve ser o espaço de flexibilidade para a decisão, que deverá ser tomada através de consultas públicas a todos os atores sociais. Apesar de não seguir os critérios e classes propostos, o ZEEM aprovado no PLAM de Rio Grande não apresentou grandes diferenças espaciais de proposição de usos quando comparado ao ZEEC proposto. Portanto, o ZEEM atual deve ser testado na prática, implementado e revisado periodicamente, o que seria uma boa oportunidade a adequação aos critérios propostos no PNGC. / This work dealt with two instruments created by the Brazilian Government to support the environmental management in the context of the Brazilian National Plan for Coastal Management (PNGC), using the city of Rio Grande (RS) as a case study. Such instruments were the Geographical Information System of the Coastal Zone (SIGERCO) and the Coastal Ecological-Economic Zoning (ZEEC). It consisted of the organization and integration of data in the SIGERCO in a manner that can assist the development of a simple methodology for the elaboration of the ZEEC. There is strong demand that coastal cities elaborate their ZEEC; however, previous experiences have used methodologies and results that do not follow the criteria and classification defined in the PNGC. For ZEEC construction, the definition of Environmental Management Units (EMU’s) is necessary. Therefore, diverse types of territorial division already elaborated in the city area were compiled. Geomorphology was chosen for defining the geographical limits of the EMUs, based on previous experiences in literature. The criteria defined by the PNGC for the ZEEC are subjective, making an enormous gamma of distinct zonings possible, depending on the weights attributed to each criterion and the chosen class breaks. In this work, four ZEEC experiments were evaluated and compared, as well as a ZEEC following the State of Santa Catarina zoning and the zoning approved in the Municipal Environmental Plan (PLAM) of Rio Grande. The SIGERCO organized for this city can represent a large improvement in comprehension and diffusion of scientific knowledge to decision-makers. However, it has to be available on the internet, and constantly updated. The ZEEC methodology proposed in this work demands few data for its elaboration, consisting basically of geomorphological and land-use maps and socio-economic data collected by IBGE. This makes possible the fast adequacy of zonings already elaborated and the construction of new ones for the entire Brazilian coast. Moreover, the establishment of criteria weights and class breaks must be carried out through public consultations, involving decision-makers, scientific community and organized civil society. Although it did not follow the established methodology, the ZEEM approved in the PLAM did not present large spatial differences in the uses proposition when compared to the ZEEC. Therefore, the ZEEM must be tested in the real world and periodically be revised. This would be a good opportunity for adjusting it to the criteria considered in the National Plan for Coastal Management.

Submitted by Geyciane Santos (geyciane_thamires@hotmail.com) on 2015-07-27T15:15:30Z No. of bitstreams: 1 Dissertação - Jorge Alberto Lopes da Costa.pdf: 12254367 bytes, checksum: e92aa3fbce27b2b569e2f3aae45e851d (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-07-28T15:14:18Z (GMT) No. of bitstreams: 1 Dissertação - Jorge Alberto Lopes da Costa.pdf: 12254367 bytes, checksum: e92aa3fbce27b2b569e2f3aae45e851d (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-07-28T15:19:49Z (GMT) No. of bitstreams: 1 Dissertação - Jorge Alberto Lopes da Costa.pdf: 12254367 bytes, checksum: e92aa3fbce27b2b569e2f3aae45e851d (MD5) / Made available in DSpace on 2015-07-28T15:19:50Z (GMT). No. of bitstreams: 1 Dissertação - Jorge Alberto Lopes da Costa.pdf: 12254367 bytes, checksum: e92aa3fbce27b2b569e2f3aae45e851d (MD5) Previous issue date: 2011-07-07 / Não informada / In recent decades the areas of rainforest in the Amazon region has been heavily impacted by a rapid process of conversion of vegetation cover in other types of use due to human action. In the context of global change, the use of mapping and monitoring land cover and provide information for the analysis and evaluation of environmental impacts due to accelerated changes in the landscape. Therefore, this study evaluated the potential of data from synthetic aperture radar for discriminating use and land cover in the region of Manaus, Amazonas state. We used a multipolarized image from sensor airborne SAR-R99B (L band), with 3 m spatial resolution. Were evaluated the MAXVER-ICM and SVM (Support Vector Machine) classifiers, where in all cases we used the images individually multipolarized amplitude (HH, HV and VV), in pairs (HH and HV), (HV and VV) and (HH and VV) and together (HH, HV and VV). The results were compared using as parameter the Kappa coefficient. The SVM classifier had higher accuracy compared to MAXVER-ICM classifier. The best classifications were obtained for the dual polarization (HH and VV) with MARVER-ICM classifier and (HH, HV and VV) with the SVM classifier both using the images with the filter. The accuracy was highest with SVM for classification and filter images (kappa = 0.7736). Were analyzed the influence of using GAMMA filter performance on the classifiers where it showed that filtered images have provided an increase in the results, on average, about 8%. Thus there was the analysis of the classification results, which found that the best result was provided by the dataset multipolarized (HH, HV and VV) classified by the SVM method. Thus, we concluded that the use of radar imagery in mapping thematic classes use and land cover in tropical regions, can be considered as a viable proposal. / Nas últimas décadas as áreas de floresta tropical na região Amazônica têm sido fortemente impactada por um rápido processo de conversão da cobertura vegetal em outros tipos de uso devido à ação antrópica. No contexto das mudanças globais, os mapeamentos e monitoramentos de uso e cobertura da terra fornecem subsídios para as análises e avaliações dos impactos ambientas em virtude de acelerados processos de mudança na paisagem. Neste contexto, este estudo avaliou o potencial dos dados de radar de abertura sintética para discriminação de uso e cobertura da terra na região de Manaus, estado do Amazonas. Foi utilizada uma imagem multipolarizada do sensor aerotransportado SAR-R99B (banda L), com 3 metros de resolução espacial. Realizaram-se classificações na imagem radar sem filtro e com filtro Gamma 3x3. Avaliou-se o classificador pontual MAXVER-ICM e o SVM (Support Vector Machine), onde em todos os casos utilizou-se das imagens multipolarizadas em amplitude individualmente (HH, HV e VV), aos pares (HH e HV), (HV e VV) e (HH e VV) e em conjunto (HH, HV e VV). Os resultados obtidos foram comparados utilizando-se como parâmetro o coeficiente de concordância Kappa. O classificador SVM apresentou acurácia superior em relação ao classificador MAXVER-ICM. As melhores classificações foram obtidas para a polarização dual HH e VV com o classificador MAXVER-ICM e (HH, HV e VV) com o classificador SVM ambos utilizando as imagens com filtro. A acurácia mais elevada foi para a classificação com SVM e imagens com filtro (kappa = 0,7736). Analisou-se a influência do uso de filtro GAMMA no desempenho dos classificadores onde se contatou que as imagens filtradas proporcionaram um incremento nos resultados, em média, na ordem de 8%. Deste modo realizou-se a análise dos resultados das classificações, onde se constatou que o melhor resultado foi proporcionado pelo conjunto de dados multipolarizados (HH, HV e VV)classificados através do método SVM. Assim, concluiu-se que o uso de imagens de radar no mapeamento de classes temáticas de uso e cobertura da terra, em regiões tropicais, pode ser considerado como uma proposta viável.

Visual place recognition is the task of finding same places in a set of database images for a given set of query images. This becomes particularly challenging for long-term applications when the environmental condition changes between or within the database and query set, e.g., from day to night. Visual place recognition in changing environments can be used if global position data like GPS is not available or very inaccurate, or for redundancy. It is required for tasks like loop closure detection in SLAM, candidate selection for global localization, or multi-robot/multi-session mapping and map merging. In contrast to pure image retrieval, visual place recognition can often build upon additional information and data for improvements in performance, runtime, or memory usage. This includes additional data-inherent knowledge about information that is contained in the image sets themselves because of the way they were recorded. Using data-inherent knowledge avoids the dependency on other sensors, which increases the generality of methods for an integration into many existing place recognition pipelines. This thesis focuses on the usage of additional data-inherent knowledge. After the discussion of basics about visual place recognition, the thesis gives a systematic overview of existing data-inherent knowledge and corresponding methods. Subsequently, the thesis concentrates on a deeper consideration and exploitation of four different types of additional data-inherent knowledge. This includes 1) sequences, i.e., the database and query set are recorded as spatio-temporal sequences so that consecutive images are also adjacent in the world, 2) knowledge of whether the environmental conditions within the database and query set are constant or continuously changing, 3) intra-database similarities between the database images, and 4) intra-query similarities between the query images. Except for sequences, all types have received only little attention in the literature so far. For the exploitation of knowledge about constant conditions within the database and query set (e.g., database: summer, query: winter), the thesis evaluates different descriptor standardization techniques. For the alternative scenario of continuous condition changes (e.g., database: sunny to rainy, query: sunny to cloudy), the thesis first investigates the qualitative and quantitative impact on the performance of image descriptors. It then proposes and evaluates four unsupervised learning methods, including our novel clustering-based descriptor standardization method K-STD and three PCA-based methods from the literature. To address the high computational effort of descriptor comparisons during place recognition, our novel method EPR for efficient place recognition is proposed. Given a query descriptor, EPR uses sequence information and intra-database similarities to identify nearly all matching descriptors in the database. For a structured combination of several sources of additional knowledge in a single graph, the thesis presents our novel graphical framework for place recognition. After the minimization of the graph's error with our proposed ICM-based optimization, the place recognition performance can be significantly improved. For an extensive experimental evaluation of all methods in this thesis and beyond, a benchmark for visual place recognition in changing environments is presented, which is composed of six datasets with thirty sequence combinations.

The first International Congress of Mathematicians (ICM) was held in Zurich in 1897, setting the standards for all future ICMs. Whilst giving an overview of the congress itself, this thesis focuses on the Swiss organisers, who were predominantly university professors and secondary school teachers. As this thesis aims to offer some insight into their lives, it includes their biographies, highlighting their individual contributions to the congress. Furthermore, it explains why Zurich was chosen as the first host city and how the committee proceeded with the congress organisation. Two of the main organisers were the Swiss geometers Carl Friedrich Geiser (1843-1934) and Ferdinand Rudio (1856-1929). In addition to the congress, they also made valuable contributions to mathematical education, and in Rudio's case, the history of mathematics. Therefore, this thesis focuses primarily on these two mathematicians. As for Geiser, the relationship to his great-uncle Jakob Steiner is explained in more detail. Furthermore, his contributions to the administration of the Swiss Federal Institute of Technology are summarised. Due to the overarching theme of mathematical education and collaborations in this thesis, Geiser's schoolbook "Einleitung in die synthetische Geometrie" is considered in more detail and Geiser's methods are highlighted. A selection of Rudio's contributions to the history of mathematics is studied as well. His book "Archimedes, Huygens, Lambert, Legendre" is analysed and compared to E W Hobson's treatise "Squaring the Circle". Furthermore, Rudio's papers relating to the commentary of Simplicius on quadratures by Antiphon and Hippocrates are considered, focusing on Rudio's translation of the commentary and on "Die Möndchen des Hippokrates". The thesis concludes with an analysis of Rudio's popular lectures "Leonhard Euler" and "Über den Antheil der mathematischen Wissenschaften an der Kultur der Renaissance", which are prime examples of his approach to the history of mathematics.