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Uma proposta imuno-inspirada para segmentação de imagens com texturas usando transformada wavelet packet / An immune-inspired proposal for textured image segmentation using wavelet packet transformSilva, Karinne Saraiva da 15 August 2018 (has links)
Orientador: Yuzo Iano / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-15T16:56:14Z (GMT). No. of bitstreams: 1
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Previous issue date: 2010 / Resumo: Segmentação de texturas é um ponto crucial em muitas aplicações da área de visão computacional e processamento digital de imagens. Muitas são as aplicações que utilizam imagens com texturas, como: sensoriamento remoto, análise de imagens médicas, inspeção industrial, etc. Para análise de texturas, é essencial o uso de um extrator de características capaz de representar bem cada textura presente na imagem. A transformada wavelet packet fornece a caracterização necessária para discriminação de texturas, oferecendo também uma representação multi-escala, ferramenta muito importante na análise de texturas. Outro ponto importante neste trabalho, é o fato da metodologia aqui proposta ser não supervisionada. Para tal, é utilizado o algoritmo de clusterização ARIA, que determina automaticamente o número de clusters presentes no conjunto de dados. A eficiência do método desenvolvido é comprovada aplicando-o em diversas imagens, como: mosaicos de Brodatz, imagens naturais, imagens médicas e outras aplicações. / Abstract:Texture segmentation is a crucial aspect in many computer vision and digital image processing applications. Several of these applications use texture images, such as remote sensing, medical image analysis, industrial inspection, etc. For texture analysis, it is essential to use a feature-extractor that can represent precisely each of the textures present in the picture. The wavelet packet transform provides the characteristics required for discrimination of the textures, as well as offering a multi-scale representation, which is a very important tool in texture analysis. Another important aspect in this work is that the proposed methodology is unsupervised. To achieve that, the clustering algorithm ARIA is used, which automatically determines the number of clusters present in the data set. The efficiency of the developed method is clear in the application of the method on several types of images, such as mosaics of Brodatz, natural images, medical images and other applications. / Mestrado / Telecomunicações e Telemática / Mestre em Engenharia Elétrica
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Metodologia multi-estágio para restabelecimento de sistemas elétricos de distribuição utilizando algoritmos bio-inspiradosArcanjo, Diego Nascimento 24 July 2014 (has links)
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Previous issue date: 2014-07-24 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Neste trabalho é proposto uma metodologia multi-estágio utilizando algoritmos bio-inspirados para a resolução do processo de Restabelecimento de Sistemas Elétricos de Distribuição.
O primeiro estágio consiste na solução de uma função multi-objetivo visando a determinação da configuração final das chaves do sistema após isolados os ramos defeituosos (configuração de pós-contingência). Neste estágio, a modelagem da função multi-objetivo busca uma configuração adequada de chaves para minimizar a carga não suprida, as perdas do sistema, o número de chaveamentos, penalizando as violações aos limites operativos do sistema e considerando a presença de consumidores prioritários. Adicionalmente, a restrição de radialidade é assegurada em cada configuração utilizando, caso necessário, uma técnica de abertura de laço.
A partir da configuração final obtida no primeiro estágio, são identificadas as chaves que foram manobradas.
O segundo estágio da metodologia busca a determinação da sequência de chaveamento levando em conta a minimização da energia não suprida. Essa formulação permite que o tempo de manobra das chaves possa ser considerado. Sendo necessário, é realizado, ainda neste estágio, cortes mínimos discretos de carga para cada manobra executada.
Em ambos os estágios foram utilizadas algoritmos bio-inspirados como métodos de solução dos respectivos problemas de otimização não-lineares inteiros mistos. As técnicas utilizadas são: Algoritmos Genéticos, Método da Eco Localização de Morcegos (Bat Algorithm) e Método da Reprodução dos Pássaros Cuco (Cuckoo Search).
Os desenvolvimentos do algoritmo proposto foi implementado no ambiente MatLab®. Os resultados obtidos foram comparados com outras metodologias conhecidas da literatura comprovando a eficiência e robustez da técnica proposta. / This dissertation proposes a methodology for solving multi-stage process of Restoration on Power Distribution Systems using Nature-Inspired Algorithms.
The first stage consists in solving a fitness multi-objective function in order to determine the final configuration of the switches after the faulted branches were isolated (post-contingency configuration). In this stage the multi-objective function seeks through the suitable configuration to minimize the undelivered power, the power losses, the number of switching, penalizing for violation in the system operational limits and taking in consideration the presence of priority load in the system. Additionally the radiality constraint is improved using an open loop technique.
After the final configuration is obtained, for the first stage, the switches which were maneuvered are identified.
The second stage of the methodology is to determine the sequence of switching taking into account the minimization of energy not supplied. This formulation allows to consider the switching operation time. If necessary, the minimum discrete load shedding procedure is made for each maneuvered switch.
In both stages Nature-Inspired Algorithms to solve mixed integer nonlinear programming problems were used. The techniques used are: Genetic Algorithms, Bat Algorithm and Cuckoo Search.
The developments of the proposed algorithm were implemented in MatLab ® environment. The results obtained were compared with other well-known methodologies showing the efficiency and robustness of the proposed technique.
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Alocação de geração distribuída em sistemas de distribuição de energia elétrica via otimização bioinspirada na ecolocalização de morcegosCoelho, Francisco Carlos Rodrigues 16 August 2013 (has links)
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Previous issue date: 2013-08-16 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A alocação de geração distribuída em sistemas de distribuição de energia elétrica
consiste em definir a localização ótima para instalação de centrais geradoras distribuídas no
sistema e a quantidade de potência que deverá ser injetada por estas centrais, de modo a
minimizar as perdas técnicas inerentes aos sistemas de distribuição. Este é um problema de
otimização de difícil solução e que apresenta implicações ambientais e econômicas.
A técnica de otimização empregada nesta pesquisa para determinar a alocação dos
geradores distribuídos é recente, sendo a mesma bioinspirada. Ela se baseia na ecolocalização
de morcegos e foi desenvolvida em 2010 pelo pesquisador Xin-She Yang. Esta técnica de
otimização agrega em sua constituição conhecimento prévio adquirido por outras técnicas de
otimização, como enxame de partículas e busca harmônica, utilizando assim, as vantagens
inerentes a cada uma destas ferramentas. Esta característica confere à otimização via
ecolocalização uma expectativa de sucesso em problemas de difícil solução, com
características combinatórias, que é o caso do problema em estudo.
Com o intuito de melhorar o desempenho da técnica de otimização em questão, foi
proposta uma etapa adicional em sua constituição. Esta alteração no algoritmo original se
mostrou eficiente nas simulações realizadas, pois o mecanismo de busca modificado alcançou
resultados de melhor qualidade com maior frequência, tanto em sua validação, onde foram
utilizadas funções matemáticas não convexas, como na aplicação do método ao problema
referente à alocação de geração distribuída em sistemas de distribuição de energia elétrica.
Utilizando-se três sistemas teste, de trinta e três, de cinquenta e de sessenta e nove
barras, foram realizados testes com alocação exclusiva de potência ativa e reativa, e também
alocação simultânea destes dois tipos de potência, sendo que os resultados obtidos foram
comparados com resultados presentes na literatura especializada. Além das perdas, fatores
como perfil de tensão resultante nas barras e trajetória de convergência do algoritmo inspirado
na ecolocalização de morcegos foram analisados para a avaliação da metodologia de
otimização empregada nesta pesquisa. / The optimal distributed generation placement in electrical power systems is a complex
problem involving environmental and economical issues. The solution to this problem
consists of choosing the optimum location of distributed power plants, and to define the
amount of power that must be injected by these plants in order to minimize technical losses in
electrical distribution systems.
The optimization technique utilized in this work to determine the placement of
distributed generators is recent. It was developed in 2010 by Xin-She Yang. The optimization
procedure is inspired by the echolocation of bats phenomenon, and uses some previous
knowledge from others techniques, like Particle Swarm Optimization and Harmony Search,
combining their advantages. This feature gives the Bat-Inspired Algorithm an expectation of
success on difficult problems, such as the combinatorial problem under study.
In order to improve the performance of the optimization technique an additional step
was proposed in its search engine. Endowed with this change, the algorithm has achieved
better results more frequently. Nonconvex benchmark mathematical functions were used, as
well as in its application on distributed generation placement.
Using three different bus systems (33, 50 and 69 busses), simulations were performed
placing real and reactive Power separately, and those two kind of Power together. The
produced results were compared to specialized literature. Real power losses, bus voltage and
convergence trajectory indicates the level of success reached by the optimization technique
utilized in this research work.
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Algoritmos bio-inspirados para minimização do makespan do problema de escalonamento de produção / Bio-inspired algorithms for minimizing the makespan of the production scheduling problemCarvalho, Marcia Braga de 19 August 2018 (has links)
Orientadores: Akebo Yamakami, Tatiane Regina Bonfim / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-19T06:06:35Z (GMT). No. of bitstreams: 1
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Previous issue date: 2011 / Resumo: Este trabalho propõe novas abordagens híbridas baseadas em técnicas da computação bio-inspirada para o problema de escalonamento do tipo Job Shop. Como o problema do tipo job shop pertence a classe NP-difícil e não existe algoritmo exato capaz de solucionar todos os tipos deste problema. Normalmente é necessária a elaboração de métodos de resolução mais sofisticados para contornar essa alta complexidade. Desta forma, nesta tese propomos abordagens híbridas baseadas em algoritmo memético e algoritmo de otimização por colônia de formigas a fim de contornar essa complexidade e ser capaz de explorar eficientemente o espaço de busca obtendo resultados de alta qualidade. Os algoritmos híbridos propostos são aplicados tanto no problema de job shop com tempo de processamento preciso, como nos problemas de job shop com tempo de processamento incerto. No caso de problema com tempo de processamento incerto, os algoritmos visam encontrar um conjunto diversificado de escalonamentos com alto grau de possibilidade de serem ótimos / Abstract: This work proposes new hybrid approaches based on techniques of bio-inspired computing for the Job Shop scheduling problem. As the job shop scheduling problem is NP-hard and there is no exact algorithm capable of solving all kinds of this problem. Usually it is necessary to elaborate more sophisticated methods of resolution to overcome this high complexity. Thus, in this work we propose hybrid approaches based on memetic algorithm and ant colony optimization algorithm in order to explore the search space in an efficient manner and obtain high quality results. The proposed hybrid algorithms are applied in both the job shop scheduling problem with precise processing time, as in job shop scheduling problems with uncertain processing time. In the case of problem with uncertain processing time, the algorithms obtain a diversified set of schedules with high possibility of being optimal / Doutorado / Automação / Doutor em Engenharia Elétrica
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Conception des catalyseurs hétérogènes bio-inspirés à base de métaux divalents greffés dans des silices mésoporeuses pour l'activation de CO2 / Design of heterogeneous bio-inspired catalysts using divalent metals anchored into mesoporous silica for CO2 activationDoghri, Hanène Kaouther 29 June 2017 (has links)
Des complexes bio-inspirés de zinc(II) ont été ancrés à la surface des nanopores d’une silice mésoporeuse de type MCM-41 adopté la technique du pochoir moléculaire à motifs périodiques pour assurer l’isolation des sites en utilisant des ions TMA+ comme espaceur pour contrôler le greffage des fonctions triméthylsilyle. L’objectif étant de mimer le doigt de zinc de l’anhydrase carbonique, une enzyme qui catalyse la réaction réversible d’hydratation du dioxyde de carbone en bicarbonate. Des complexes aminés de métaux de transition ont été aussi ancrés par analogie au site métallique de l’anhydrase carbonique avec un contrôle du voisinage moléculaire comparable à celui des matériaux contenant les complexes à base de zinc. L’interaction du CO2 adsorbé avec les sites actifs de ces matériaux a été aussi étudiée. Les matériaux intermédiaires sont caractérisés à chaque étape par un panel de techniques, dont DRX, analyses élémentaires, adsorption-désorption d’N2, FT-IR, 29Si RMN, XPS et RPE qui confirment l’intégrité de la structure poreuse et la formation des complexes. / Bio-inspired diethylenetriamine zinc(II) complexes were anchored into the nanopores of hexagonal mesoporous MCM41-like silicas. A step-by-step approach called “Molecular Stencil Patterning” was adopted to perform an in situ synthesis in order to mimic the zinc finger of the carbonic anhydrase. In the presence of a surface-masking pattern of TMA+ ions, some silanol groups were capped using grafted trimethylsilyl functions. Transition metal complexes have also been anchored in analogy to the metallic site of carbonic anhydrase with a molecular vicinity control comparable to that of materials containing zinc complexes. The interaction of adsorbed CO2 with the active sites of these materials has also been studied. The materials were characterized with a panel of techniques including XRD, elemental analysis, N2-adsorption-desorption, FT-IR, 29Si NMR, XPS and EPR that confirm the integrity of the porous structure and the complexes formation.
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Division of labour in groups of robotsLabella, Thomas Halva 09 February 2007 (has links)
In this thesis, we examine algorithms for the division of labour in a group of robot. The algorithms make no use of direct communication. Instead, they are based only on the interactions among the robots and between the group and the environment.<p><p>Division of labour is the mechanism that decides how many robots shall be used to perform a task. The efficiency of the group of robots depends in fact on the number of robots involved in a task. If too few robots are used to achieve a task, they might not be successful or might perform poorly. If too many robots are used, it might be a waste of resources. The number of robots to use might be decided a priori by the system designer. More interestingly, the group of robots might autonomously select how many and which robots to use. In this thesis, we study algorithms of the latter type.<p><p>The robotic literature offers already some solutions, but most of them use a form of direct communication between agents. Direct, or explicit, communication between the robots is usually considered a necessary condition for co-ordination. Recent studies have questioned this assumption. The claim is based on observations of animal colonies, e.g. ants and termites. They can effectively co-operate without directly communicating, but using indirect forms of communication like stigmergy. Because they do not rely on communication, such colonies show robust behaviours at group level, a condition that one wishes also for groups of robots. Algorithms for robot co-ordination without direct communication have been proposed in the last few years. They are interesting not only because they are a stimulating intellectual challenge, but also because they address a situation that might likely occur when using robots for real-world out-door applications. Unfortunately, they are still poorly studied.<p><p>This thesis helps the understanding and the development of such algorithms. We start from a specific case to learn its characteristics. Then we improve our understandings through comparisons with other solutions, and finally we port everything into another domain.<p><p>We first study an algorithm for division of labour that was inspired by ants' foraging. We test the algorithm in an application similar to ants' foraging: prey retrieval. We prove that the model used for ants' foraging can be effective also in real conditions. Our analysis allows us to understand the underlying mechanisms of the division of labour and to define some way of measuring it.<p><p>Using this knowledge, we continue by comparing the ant-inspired algorithm with similar solutions that can be found in the literature and by assessing their differences. In performing these comparisons, we take care of using a formal methodology that allows us to spare resources. Namely, we use concepts of experiment design to reduce the number of experiments with real robots, without losing significance in the results.<p><p>Finally, we apply and port what we previously learnt into another application: Sensor/Actor Networks (SANETs). We develop an architecture for division of labour that is based on the same mechanisms as the ants' foraging model. Although the individuals in the SANET can communicate, the communication channel might be overloaded. Therefore, the agents of a SANET shall be able to co-ordinate without accessing the communication channel. / Doctorat en sciences appliquées / info:eu-repo/semantics/nonPublished
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Neuro-inspired Architectures for the Acquisition and Processing of Visual Information / Architectures neuro-inspirées pour l'acquisition et le traitement de l'information visuelleAboudib, Ala 02 December 2016 (has links)
L'apprentissage automatique et la vision par ordinateur sont deux sujets de recherche d'actualité. Des contributions clés à ces domaines ont été les fruits de longues années d'études du cortex visuel et de la fonction des réseaux cérébraux. Dans cette thèse, nous nous intéressons à la conception des architectures neuro-inspirées pour le traitement de l'information sur trois niveaux différents du cortex visuel. Au niveau le plus bas, nous proposons un réseau de neurones pour l'acquisition des signaux visuels. Ce modèle est étroitement inspiré par le fonctionnement et l'architecture de la retine et les premières couches du cortex visuel chez l'humain. Il est également adapté à l'émulation des mouvements oculaires qui jouent un rôle important dans notre vision. Au niveau le plus haut, nous nous intéressons à la mémoire. Nous traitons un modèle de mémoire associative basée sur une architecture neuro-inspirée dite `Sparse Clustered Network (SCN)'. Notre contribution principale à ce niveau est de proposer une amélioration d'un algorithme utilisé pour la récupération des messages partiellement effacés du SCN. Nous suggérons également une formulation générique pour faciliter l'évaluation des algorithmes de récupération, et pour aider au développement des nouveaux algorithmes. Au niveau intermédiaire, nous étendons l'architecture du SCN pour l'adapter au problème de la mise en correspondance des caractéristiques d'images, un problème fondamental en vision par ordinateur. Nous démontrons que la performance de notre réseau atteint l'état de l'art, et offre de nombreuses perspectives sur la façon dont les architectures neuro-inspirées peuvent servir de substrat pour la mise en oeuvre de diverses tâches de vision. / Computer vision and machine learning are two hot research topics that have witnessed major breakthroughs in recent years. Much of the advances in these domains have been the fruits of many years of research on the visual cortex and brain function. In this thesis, we focus on designing neuro-inspired architectures for processing information along three different stages of the visual cortex. At the lowest stage, we propose a neural model for the acquisition of visual signals. This model is adapted to emulating eye movements and is closely inspired by the function and the architecture of the retina and early layers of the ventral stream. On the highest stage, we address the memory problem. We focus on an existing neuro-inspired associative memory model called the Sparse Clustered Network. We propose a new information retrieval algorithm that offers more flexibility and a better performance over existing ones. Furthermore, we suggest a generic formulation within which all existing retrieval algorithms can fit. It can also be used to guide the design of new retrieval approaches in a modular fashion. On the intermediate stage, we propose a new way for dealing with the image feature correspondence problem using a neural network model. This model deploys the structure of Sparse Clustered Networks, and offers a gain in matching performance over state-of-the-art, and provides a useful insight on how neuro-inspired architectures can serve as a substrate for implementing various vision tasks.
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Perfectionnement des algorithmes de contrôle-commande des robots manipulateur électriques en interaction physique avec leur environnement par une approche bio-inspirée / Improvement of control algorithms of electrical robot arms in physical interaction with their environment with bio-inspired approachMelnyk, Artem 18 December 2014 (has links)
Les robots intégrés aux chaînes de production sont généralement isolés des ouvriers et ne prévoient pas d'interaction physique avec les humains. Dans le futur, le robot humanoïde deviendra un partenaire pour vivre ou travailler avec les êtres humains. Cette coexistence prévoit l'interaction physique et sociale entre le robot et l'être humain. En robotique humanoïde les futurs progrès dépendront donc des connaissances dans les mécanismes cognitifs présents dans les interactions interpersonnelles afin que les robots interagissent avec les humains physiquement et socialement. Un bon exemple d'interaction interpersonnelle est l'acte de la poignée de la main qui possède un rôle social très important. La particularité de cette interaction est aussi qu'elle est basée sur un couplage physique et social qui induit une synchronisation des mouvements et des efforts. L'intérêt d'étudier la poignée de main pour les robots consiste donc à élargir leurs propriétés comportementales pour qu'ils interagissent avec les humains de manière plus habituelle.Cette thèse présente dans un premier chapitre un état de l'art sur les travaux dans les domaines des sciences humaines, de la médecine et de la robotique humanoïde qui sont liés au phénomène de la poignée de main. Le second chapitre, est consacré à la nature physique du phénomène de poignée de main chez l'être humain par des mesures quantitatives des mouvements. Pour cela un système de mesures a été construit à l'Université Nationale Technique de Donetsk (Ukraine). Il est composé d'un gant instrumenté par un réseau de capteurs portés qui permet l'enregistrement des vitesses et accélérations du poignet et les forces aux points de contact des paumes, lors de l'interaction. Des campagnes de mesures ont permis de montrer la présence d'un phénomène de synchronie mutuelle précédé d'une phase de contact physique qui initie cette synchronie. En tenant compte de cette nature rythmique, un contrôleur à base de neurones rythmiques de Rowat-Selverston, intégrant un mécanisme d'apprentissage de la fréquence d'interaction, est proposé et etudié dans le troisième chapitre pour commander un bras robotique. Le chapitre quatre est consacré aux expériences d'interaction physique homme/robot. Des expériences avec un bras robotique Katana montrent qu'il est possible d'apprendre à synchroniser la rythmicité du robot avec celle imposée par une per-sonne lors d'une poignée de main grâce à ce modèle de contrôleur bio-inspiré. Une conclusion générale dresse le bilan des travaux menés et propose des perspectives. / Automated production lines integrate robots which are isolated from workers, so there is no physical interaction between a human and robot. In the near future, a humanoid robot will become a part of the human environment as a companion to help or work with humans. The aspects of coexistence always presuppose physical and social interaction between a robot and a human. In humanoid robotics, further progress depends on knowledge of cognitive mechanisms of interpersonal interaction as robots physically and socially interact with humans. An illustrative example of interpersonal interaction is an act of a handshake that plays a substantial social role. The particularity of this form of interpersonal interaction is that it is based on physical and social couplings which lead to synchronization of motion and efforts. Studying a handshake for robots is interesting as it can expand their behavioral properties for interaction with a human being in more natural way. The first chapter of this thesis presents the state of the art in the fields of social sciences, medicine and humanoid robotics that study the phenomenon of a handshake. The second chapter is dedicated to the physical nature of the phenomenon between humans via quantitative measurements. A new wearable system to measure a handshake was built in Donetsk National Technical University (Ukraine). It consists of a set of several sensors attached to the glove for recording angular velocities and gravitational acceleration of the hand and forces in certain points of hand contact during interaction. The measurement campaigns have shown that there is a phenomenon of mutual synchrony that is preceded by the phase of physical contact which initiates this synchrony. Considering the rhythmic nature of this phenomenon, the controller based on the models of rhythmic neuron of Rowat-Selverston, with learning the frequency during interaction was proposed and studied in the third chapter. Chapter four deals with the experiences of physical human-robot interaction. The experimentations with robot arm Katana show that it is possible for a robot to learn to synchronize its rhythm with rhythms imposed by a human during handshake with the proposed model of a bio-inspired controller. A general conclusion and perspectives summarize and finish this work.
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Etude de la relation structure-activité de complexes bio-inspirés de la réductase de l'oxyde nitreux / Structure-activity relationships in copper complexes bio-inspired from nitrous oxide reductaseEsmieu, Charlène 13 November 2014 (has links)
Etude de la relation structure-activité de complexes bio-inspirés de la réductase de l'oxyde nitreux N2O est un puissant gaz à effet de serre et est impliqué dans la destruction de la couche d'ozone, ce qui rend sa dégradation très intéressante. Il s'agit d'un intermédiaire du cycle catalytique de la nitrification bactérienne. En effet, en biologie une métalloenzyme est capable de réduire N2O à deux électrons en N2 et H2O. Le site actif de la réductase de l'oxyde nitreux, le centre CuZ, renferme l'unique association de quatre ions cuivre pontés par un ion sulfure. Afin d'obtenir des complexes capables d'activer N2O et d'approfondir la compréhension du mécanisme catalytique de l'enzyme nous avons élaboré des modèles inspirés du centre CuZ. Il s'agit de complexes dinucléaires de cuivres possédant le motif {Cu2(µ-S)} supposé indispensable à l'activation de N2O. Les complexes à valence mixtes décrits dans ces travaux ont été complétements caractérisés et leur activité vis-à-vis de la réduction de N2O a été évaluée. Ces complexes constituent le premier modèle de ce type capable de réduire N2O. Des études spectroscopiques, électrochimiques et théoriques nous ont également permises de proposer un mécanisme réactionnel, passant par la formation d'un adduit complexe-N2O. Nous avons également pu mettre en évidence le rôle crucial de la molécule d'eau, ligand exogène des complexes, dans ce mécanisme. En parallèle, la stabilité en solution de différentes liaisons disulfures présentes au sein de ligands tétranucléants, en présence de CuII, a été évaluée. La réactivité de la liaison disulfure est dépendante de la fixation des ions cuivre à proximité des atomes de soufres. Trois ligands possédants des substituants aminés différents ont été testés, chacun présentant une réactivité particulière. Nous avons montré pour l'un de ces ligands que l'oxydation de la liaison disulfure pouvait être réalisée en absence d'oxydant fort, l'eau jouant le rôle de nucléophile. / Structure-activity relationships in copper complexes bio-inspired from nitrous oxide reductase N2O is a powerful greenhouse gas and is involved in the ozone layer destruction, which makes it degradation very interesting. N2O is an intermediate of the catalytic cycle of bacterial nitrification. Indeed, in biology a metalloenzyme can reduce N2O with two electrons to N2 and H2O. The active site of nitrous oxide reductase, the CuZ center, contains a unique combination of four copper ions bridged by a sulfide ion. In order to obtain complexes able to activate N2O and deepen the understanding of the catalytic mechanism of the enzyme we have developed models based on the CuZ center. Binuclear copper containing the {Cu2(μ-S)} pattern that is supposed essential to N2O activation have been synthetized. Mixed valent complexes described in this work were fully characterized and their activity toward N2O was evaluated. These complexes are the first model like this capable of N2O reduction. Spectroscopic, electrochemical and theoretical studies have also allowed us to propose a reaction mechanism, which passes through the formation of an adduct complex-N2O. We were also able to highlight the crucial role of the exogenous water molecule in this mechanism. In parallel, the solution stability of different disulfide bonds present in tetranucleating ligands in the presence of CuII was evaluated. The reactivity of the disulfide bond is dependent upon the binding of copper ions near sulfur atoms. Three ligands with different amino groups were tested, each having a specific reactivity. We have shown for one of them that the oxidation of the disulfide bond could be carried out in the absence of strong oxidizer, water acting as the nucleophil
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Evoluční návrh struktur využívající přepisovací systémy / Evolutionary Design of Structures Using Rewriting SystemsDobeš, Michal January 2017 (has links)
This work focuses on application of rewriting systems in the context of biology-inspired development of structures in evolutionary algorithms. As a part of this work, a method has been proposed for design of general structures that uses the aforementioned principle. This document includes an introduction into the theory of sorting networks and their design, the problem of which is later shown to be solvable using the proposed method. In addition, the theoretical background of evolutionary algorithms and rewriting systems is discussed. In the field of rewriting systems, an extension to the class of IL-systems has been created for use in the proposed method. The proposed method has been successfuly applied in the design of growing sorting networks. The results produced by the proposed method significantly outperform the results of the currently best-known comparable method.
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