Bien que le traitement conjoint des mesures multimodales soit supposé conduire à de meilleures performances que celles obtenues en exploitant une seule modalité ou plusieurs modalités indépendamment, il existe des exemples en littérature qui prouvent que c'est pas toujours vrai. Dans cette thèse, nous analysons rigoureusement, en termes d'information mutuelle et d'erreur d'estimation, les différentes situations de l'analyse multimodale afin de déterminer les conditions conduisant à des performances optimales.Dans la première partie, nous considérons le cas simple de deux ou trois modalités, chacune étant associée à la mesure bruitée d'un signal, avec des liens entre modalités matérialisés par les corrélations entre les parties utiles du signal et par les corrélations les bruits. Nous montrons comment les performances obtenues sont améliorées avec l'exploitation des liens entre les modalités. Dans la seconde partie, nous étudions l'impact sur les performances d'erreurs sur les liens entre modalités. Nous montrons que ces fausses hypothèses dégradent les performances, qui peuvent alors devenir inférieure à celles atteintes avec une seule modalité.Dans le cas général, nous modélisons les multiples modalités comme un canal gaussien bruité. Nous étendons alors des résultats de la littérature en considérant l'impact d'erreurs sur les densités de probabilité du signal et du bruit sur l'information transmise par le canal. Nous analysons ensuite cette relation dans la cas d'un modèle simple de deux modalités. Nos résultats montrent en particulier le fait inattendu qu'une double inadéquation du bruit et du signal peuvent parfois se compenser et ainsi conduire à de très bonnes performances. / The joint processing of multimodal measurements is supposed to lead to better performances than those obtained using a single modality or several modalities independently. However, in literature, there are examples that show that is not always true. In this thesis, we analyze, in terms of mutual information and estimation error, the different situations of multimodal analysis in order to determine the conditions to achieve the optimal performances.In the first part, we consider the simple case of two or three modalities, each associated with noisy measurement of a signal. These modalities are linked through the correlations between the useful parts of the signal and the correlations between the noises. We show that the performances are improved if the links between the modalities are exploited. In the second part, we study the impact on performance of wrong links between modalities. We show that these false assumptions decline the performance, which can become lower than the performance achieved using a single modality.In the general case, we model the multiple modalities as a noisy Gaussian channel. We then extend literature results by considering the impact of the errors on signal and noise probability densities on the information transmitted by the channel. We then analyze this relationship in the case of a simple model of two modalities. Our results show in particular the unexpected fact that a double mismatch of the noise and the signal can sometimes compensate for each other, and thus lead to very good performances.

L’adverbe est l’une des catégories invariables du discours. Le définir clairement n’est pas toujours chose aisée, tant cette catégorie grammaticale regorge de mots d’une grande hétérogénéité, non seulement du point de vue de leur nature, mais également du point de vue de leur rôle. L’adverbe peut ainsi signifier la comparaison, le lieu, la manière ou la qualité, l’ordre et le rang, la quantité, le temps, etc. Il peut encore servir de connecteur logique, de négation, etc. Lorsque l’adverbe permet de répondre à la question « où ? » posé autour du verbe, on parle d’adverbe locatif, traditionnellement appelé adverbe de lieu. C’est à cette catégorie d’adverbes que nous avons consacré notre étude. Les adverbes locatifs ont rarement fait l’objet d’une étude exhaustive, ce qui nous a amené à nous intéresser à leur classification dans le cadre théorique du lexique-grammaire. Pour parvenir à nos fins, nous nous sommes proposé pour objectif principal de mettre en évidence les différentes propriétés syntactico-sémantiques de ces adverbes locatifs. Mais avant d’en arriver-là, il était nécessaire de clarifier la notion très ambivalente de lieu, ce vocable permettant en effet de regrouper des réalités diverses telles que les lieux ayant un sens purement locatif (ex. ici, là-haut) et les lieux impliquant l’idée d’activités qui leur sont associées (ex. au cinéma, à l’école), pour ne citer que ces deux exemples. Il s’agissait donc de mettre en évidence cette classification interne au sein même de cette dernière notion de lieu. Ainsi, nous parlons d’adverbes locatifs non prédicatifs pour désigner les adverbes ayant un sens de lieu impliquant également un sens d’activité associée à ce lieu. De même, les adverbes locatifs prédicatifs pour parler des adverbes désignant explicitement une activité liée à un lieu tout en possédant une référence de lieu rendant possible une telle activité. Compte tenu de la rareté des études qui examinent de manière systématique le lien entre la notion de lieu et les adverbes de lieu, tout l’intérêt de notre démarche aura été d’élaborer une approche analytique qui rende compte des phénomènes sémantico-syntaxiques propres aux adverbes locatifs. Cette étude est d’autant plus nécessaire que l’absence d’une méthode d’analyse a souvent fait obstacle à l’établissement d’une classification des adverbes locatifs. / The adverb is an invariable part of discourse. Defining it with clarity is not a simple assignment, as this category in grammar is filled with words of great heterogeneity, not only from the point of view of their nature, but also from the point of view of their role. The adverb can thus mean comparison, place, manner, quality, order, rank, quantity, and time, etc. It can also be used as a logical connector, negation, etc. When the adverb allows the question "where?" to be raised around the verb, one speaks of locative adverb, traditionally known as adverb of place. It is to this category of adverbs that we have devoted our study. Locative adverbs have rarely been studied exhaustively, which has led us to consider their classification in the theoretical framework of the lexicon-grammar. In order to achieve our goals, we propose to highlight the different syntactico-semantic properties of these adverbs. But before we came to that point, it was necessary to clarify the very ambivalent notion of place, since this term allows us to gather diverse realities such as places with a purely locative sense (e.g. here, up there) and places involving the idea of activities associated within them (e.g. at the cinema, at the school), to only mention these two examples. It was therefore necessary to bring to light this internal classification within the very notion of place. Thus, we speak of non-predicative locative adverbs to denote adverbs with a sense of place that also implies a sense of activity associated with those places. Similarly, predicative locative adverbs to speak of adverbs explicitly designating an activity linked to a place while referring to a location allowing such activity to be performed Given the scarcity of studies that systematically examine the link between the notion of place and adverbs of place, all the interest of our approach will have been to develop an analytical approach that accounts for the semantico-syntactic phenomena specific to locative adverbs. This study is all the more necessary due to the absence of a method of analysis often hindered the establishment of a classification of adverbs of place.

Nous étudions plusieurs problémes reliés aux propriétés de transport dans les systèmes corrélés. La thèse contient 3 parties distinctes, chacune d'entre elles décrivant un aspect particulier. Nous avons obtenu dans chacun des cas des résultats qui permettent une meilleure compréhension du transport. Nous étudions l'effet de la dissipation et d'une perturbation extérieure dépendant du temps sur le diagramme de phases d'un systèmes à N corps à température nulle et à température finie. En présence de perturbation dépendant du temps, la dissipation joue un rôle important dans l'évolution vers un état stable indépendant du temps. Nous utilisons le formalisme de Keldysh dans l'approximation adiabatique qui permet d'étudier le diagramme de phases du système en fonction de parameter et de la température. Dans la 2ième partie, nous étudions un concept important pour la physique des systèmes métalliques à plusieurs bandes, le concept d'hybridation, et la façon dont l'hybridation affecte la supraconductivité du métal. De façon générale, une hybridation dépendante ou non du vecteur d'onde k a tendance à détruire la supraconductivité. Nous montrons dans ce chapitre qu'une hybridation antisymétrique a l'effet inverse et renforce la supraconductivité. Nous montrons que si l'hybridation est antisymétrique, la supraconductivité a des propriétés non-triviales. Nous proposons que dans un tel système, il puisse exister des fermions de Majorana, même en l'absence de couplage spin-orbite. Le dernier chapitre de la thèse porte sur les effets du couplage spin-orbite sur le transport dans les nanostructures magnétiques. Dans les nanostructures, le couplage spin-orbite joue un rôle important en raison de la brisure de symmétrie à la surface ou aux interfaces. En particulier, nous étudions l'effet de l'interaction Dzyaloshinskii-Moriya (DM) sur le transport de spin dans un système tri-couche. Nous montrons qu'il existe une interaction DM entre les moments des couches et les électrons de conduction, et l'influence de cette interaction sur le transport est étudiée dans un modèle simplifié ou chaque couche est représentée par un point. / We study some important problems related to the transport properties of many body systems. It is divided in three parts, each one focusing in a specific topic. We obtain relevant results that improve our understanding of these systems. We investigate the effect of dissipation and time-dependent external sources, in the phase diagram of a many body system at zero and finite temperature. In the presence of time-dependent perturbations, dissipation is essential for the system to attain a steady, time independent state. In order to treat this time dependent problem, we use a Keldysh approach within an adiabatic approximation that allows us to study the phase diagram of this system as a function of the parameters of the system and temperature. We also discuss the nature of the quantum phase transitions of the system. Next, we study an important concept in the physics of metallic multi-band systems, that of hybridization, and how it affects the superconducting properties of a material. A constant or symmetric $k$-dependent hybridization in general act in detriment of superconductivity. We show here that when hybridization between orbitals in different sites assumes an anti-symmetric character having odd-parity it {it{enhances}} superconductivity. The antisymmetric hybridization in a problem study in this thesis (present in Chapter 3) allow us to propose a new system where it is possible to investigate Majorana fermions, even in absence of spin-orbit interactions. In the last part of this thesis we study the effect of spin-orbit coupling (SOC) on transport properties in magnetic nanostructures. In this system SOC plays an important role, because surfaces (or interfaces) introduce symmetry breaking which is a source of spin-orbit interaction. We study the role of Dzyaloshinshkii-Moriya (DM) interaction on spin-transport in a 3 layer system. We show that there is a DM interaction between magnetics ions in the layers and spin of conduction electrons. We study the influence of this DM interaction on transport within a simple model where each layer is represented by a point.

Les oxydes d’iridium (iridates) ont attiré particulière attention au cours de la dernière décennie grâce à l’identification d’un état isolant de Mott induit par l’action conjointe du champ cristallin, de la corrélation électronique et du couplage spin-orbite. Cet état a été intensément investigué et des phases et excitations nouvelles ont été prédites théoriquement et aussi individuées expérimentalement. Sans doute, la diffusion inélastique résonante de rayons X (RIXS) est l’une des techniques les plus adoptée pour mesurer les excitations à basse énergie des iridates. En effet, la section efficace relativement large de la spectroscopie RIXS au seuil L3 de l’iridium et la bonne résolution en énergie ont encouragé l’emploi de cette technique. Cette thèse se pose un double objectif : concevoir des développements instrumentaux ayant pour but d’améliorer les possibilités offertes par la spectroscopie RIXS, et appliquer le RIXS afin d’étudier la physique à basse énergie de certains iridates.Le principal projet de développement instrumental est un nouveau spectromètre RIXS avec résolution en polarisation. L’analyse de la polarisation des rayons X diffusés permet d’obtenir des informations sur la symétrie et donc la nature des excitations. Cependant, elle est peu employée à cause de problèmes techniques qui naissent quand l’on veut préserver aussi la résolution en énergie et l’efficience du spectromètre. Même si le polarimètre RIXS projeté n’est pas encore disponible, le schéma optique a été vérifié et validé. Le polarimètre aura une résolution en énergie et une efficience équivalentes à celles des spectromètres RIXS courants. Le second développement technique comprend l’équipement permettant de réaliser des mesures RIXS à basse température et haute pression. Ces équipements ont permis d’investiguer l’évolution en pression des excitations magnétique du composé Sr3Ir2O7 en dessous de la température de Néel et jusqu’au 12 GPa. Les mesures peuvent aider l’affinage des modèles magnétiques courants pour ce système. Ces mesures démontrent que les excitations magnétiques peuvent être acquises en haute pression par la spectroscopie RIXS, démontrant ainsi la possible utilisation de cette technique dans ce nouveau domaine.Cette thèse comprend aussi des ultérieurs travails expérimentaux. Le premier considère le composé CaIrO3, dont la structure cristalline est constituée par des octaèdres partageant un sommet et une arête dans deux directions orthogonales. Du coup, les interactions magnétiques sont très différentes selon la direction cristallographique. Spécifiquement, la suppression du couplage de type Heisenberg dans la direction où les octaèdres partagent une arête produit des interactions magnétiques principalement unidimensionnelles. La caractéristique de ceux-ci est la présence d’un continuum d’excitations avec une dépendance en énergie et quantité de mouvement typique, qui a été révélé par la spectroscopie RIXS. Les excitations électroniques de CaIrO3 ont aussi des caractéristiques propres. Enfin, j’ai étudié les propriétés électroniques du composé Rb2[IrF6]. Des calculs récents proposaient que ce système possède un état d’isolant de Mott similairement aux oxydes d’iridium. Les mesures RIXS ont aidé à éclairer les propriétés électroniques de ce composé. La solidité des propriétés électroniques a été vérifiée par rapport à la substitution du métal alcalin ou de l’halogène, et à l’application de pression.Cette thèse accroit l’importance de l’utilisation de la spectroscopie RIXS dans des domaines qui étaient précédemment inexplorés. L’analyse de la polarisation des rayons X diffusés sera avantageuse dans les cas où la nature des excitations ne peut être établie sans ambiguïté. L’équipement développé pour réaliser les mesures RIXS en conditions extrêmes permet d’étudier la dynamique électronique et magnétique dans des phases de la matière inaccessibles jusqu’à aujourd’hui. / Iridium oxides (iridates) have raised notable attention in the last decade due to the identification of a Mott insulating state realized by the joint action of crystal field, electron correlation, and spin-orbit coupling. Such state has been intensively investigated and novel quantum phases and excitations have been theoretically predicted and experimentally found. Undoubtedly, one of the most employed techniques to elucidate the low-energy physics of iridates is resonant inelastic X-ray scattering (RIXS). At the iridium L3 edge, it benefits from a particularly good energy resolution, which matches the energy scales of the relevant excitations, and from a favorable inelastic cross-section. The aim of the present thesis is twofold: conceive challenging instrumental upgrades that contribute to the advancement of the technique itself, and apply RIXS to inspect the magnetic and electronic properties of selected iridates.The main instrumental development concerns the design of a new RIXS spectrometer with polarization resolution. Polarization analysis of the scattered X-rays provides useful information about the symmetry and thus the nature of an excitation. However, it is rather unexploited because of severe technical challenges when energy resolution and efficiency must be preserved. The designed RIXS spectrometer with polarization analysis capabilities is still under construction, however the optical scheme has been validated by preliminary tests. Full polarization analysis is expected without degradation of energy resolution or efficiency with respect to current state-of-the-art RIXS spectrometers. Additional technical developments include sample-environment equipment to perform RIXS experiments in low-temperature and high-pressure conditions. The equipment has been successfully utilized to investigate the magnetic dynamics of the bilayer-perovskite Sr3Ir2O7 below its Néel temperature and up to 12 GPa. Our measurements provide additional observations that may sharpen the challenge to theoretical understanding of the magnetic dynamics of this material. Moreover, we demonstrate for the first time that RIXS experiments of the magnetic dynamics can be extended to unexplored thermodynamic conditions.Besides instrumental advances, additional experimental work has been carried out in order to study the magnetic and electronic excitations of the post-perovskite CaIrO3. Owing to its peculiar crystal structure, featuring both edge- and corner-sharing octahedra, the magnetic interactions of CaIrO3 are very different along orthogonal directions. In particular, the inhibition of the Heisenberg coupling along the edge-sharing direction induces one-dimensional magnetic behavior with characteristic fractional spinon-like excitations, which have been detected by RIXS. Electronic excitations are also found to have particular properties. Finally, I have focused on the electronic structure of Rb2[IrF6], which was theoretically predicted to realize a Mott insulating state similar to the one of iridium oxides. RIXS measurements helped to elucidate the electronic properties of this compound. The robustness of the electronic state has been tested against substitutions of the alkali metal and halogen, and application of physical pressure.The present work extends the potential of the RIXS technique to domains previously unexplored, i.e. polarization analysis of the scattered X-rays and high-pressure low-temperature experiments. I hope that the instrumental upgrades and applications of RIXS discussed in this thesis will further promote the technique as a powerful and reliable tool to characterize elementary excitations in correlated-electron systems.

abstract: The critical infrastructures of the nation are a large and complex network of human, physical and cyber-physical systems. In recent times, it has become increasingly apparent that individual critical infrastructures, such as the power and communication networks, do not operate in isolation, but instead are part of a complex interdependent ecosystem where a failure involving a small set of network entities can trigger a cascading event resulting in the failure of a much larger set of entities through the failure propagation process. Recognizing the need for a deeper understanding of the interdependent relationships between such critical infrastructures, several models have been proposed and analyzed in the last few years. However, most of these models are over-simplified and fail to capture the complex interdependencies that may exist between critical infrastructures. To overcome the limitations of existing models, this dissertation presents a new model -- the Implicative Interdependency Model (IIM) that is able to capture such complex interdependency relations. As the potential for a failure cascade in critical interdependent networks poses several risks that can jeopardize the nation, this dissertation explores relevant research problems in the interdependent power and communication networks using the proposed IIM and lays the foundations for further study using this model. Apart from exploring problems in interdependent critical infrastructures, this dissertation also explores resource allocation techniques for environments enabled with cyber-physical systems. Specifically, the problem of efficient path planning for data collection using mobile cyber-physical systems is explored. Two such environments are considered: a Radio-Frequency IDentification (RFID) environment with mobile “Tags” and “Readers”, and a sensor data collection environment where both the sensors and the data mules (data collectors) are mobile. Finally, from an applied research perspective, this dissertation presents Raptor, an advanced network planning and management tool for mitigating the impact of spatially correlated, or region based faults on infrastructure networks. Raptor consolidates a wide range of studies conducted in the last few years on region based faults, and provides an interface for network planners, designers and operators to use the results of these studies for designing robust and resilient networks in the presence of spatially correlated faults. / Dissertation/Thesis / Doctoral Dissertation Computer Science 2016

In the present work the Roth s two-pole approximation (Phys. Rev. 184, 451 (1969)) has been used to investigate the role of d− p hybridization in the normal and superconducting states of an extended d− p Hubbard model. Superconductivity with singlet dx2−y2 -wave pairing is treated by following Beenen and Edwards formalism (Phys. Rev. B 52, 13636 (1995)). In the first part of this work, the effects of the hybridization on the superconductivity, in the hole-doped regime, have been studied treating Roth s band shift within two different approximations. In the first one, the band shift has been calculated in the limit U →¥ (U is the Coulomb interaction), with zero temperature and without consider the superconducting effects. These regards, are restrict to the band shift. In the other parts of the problem, U, the temperature and the superconducting effects have been considered finites. In the second approximation, the Coulomb interaction, the temperature and the superconductivity have been considered in the calculation of some relevant correlation functions present in the Roth s band shift. The obtained results show that the hybridization acts in the sense of to suppresses the superconductivity. Also, it has been verified that the first approximation overstimates the effects of the hybridization on the superconductivity. In the second part of these work, hoppings to second-nearest-neighbors have been included in the model with the purpose of reproduces adequately the asymetries (mainly those related with the Fermi surface, band structure and phase diagram) between the hole- and electron-doped systems. Particularly, it is shown that the crossover from hole-like to electronlike Fermi surface is deeply affected by the d − p hybridization in the hole doping case. It has been verified that the effect of the hybridization is most pronounced around the saddle-points, where the superconducting gap is maximum in the particular case of dx2−y2 -wave symmetry. As a consequence, the critical temperature Tc is directly affected by the hibridization. Moreover, the obtained results suggest that in the hole doped regime, the hybridization may act on the transport properties of the system due to the sign changes of the Hall coefficient when the crossover of the Fermi surface occurs. In the electron doped case, the crossover in the Fermi surface is not verified. Nevertheless, as the hybridization suppresses the density of states near the Fermi level, the superconductivity is affected. The topology of the Fermi surface in the hole and electron doping regime agree with recent experimental ARPES results for La2−xSrxCuO4 (hole doping) and Nd2−xCexCuO4 (electron doping). / Neste trabalho, foi usada a aproximação de dois-pólos proposta por L. Roth (Phys. Rev. 184, 451 (1969)), para investigar os efeitos da hibridização no estado normal e no estado supercondutor de um modelo de Hubbard d − p. Para tratar supercondutividade com simetria dx2−y2 , usou-se o procedimento de fatorização proposto por Beenen e Edwards (Phys. Rev. B 52, 13636 (1995)). Na primeira parte do trabalho, os efeitos da hibridização sobre a upercondutividade, foram investigados considerando-se duas aproximações diferentes para calcular o deslocamento de banda. O deslocamento de banda surge quando tratamos as equações de movimento das funções de Green através do método de L. Roth. Na primeira aproximação o deslocamento foi calculado para U →¥ (U ´e a interação coulombiana), temperatura igual a zero, e sem incluir os efeitos da supercondutividade. É importante destacar que essas considerações foram feitas apenas no deslocamento, as outras partes do problema foram tratadas considerando finitas, as quantidades citadas acima. Na segunda aproximação, o deslocamento de banda foi estudado incluíndo-se os efeitos de U, da temperatura e da supercondutividade. Nos dois casos observou-se que a hibridização atua no sentido de suprimir a supercondutividade. Verificou-se também que na primeira aproximação considerada no cálculo do deslocamento de banda, os efeitos da hibridização sobre a supercondutividade, são superestimados. Isso ocorre porque certas funções correlação presentes no deslocamento de banda desaparecem no limite U →¥. Na segunda parte deste trabalho, incluiu-se no modelo, um termo de salto ( hopping ) para os segundos vizinhos de um sítio i. Esse termo foi ncluído com o objetivo de reproduzir adequadamente as assimetrias entre o regime de dopagem por buracos e o regime de dopagem por elétrons. No caso particular de dopagem por buracos, observou-se que a mudança na natureza da superfície de Fermi de buraco para elétron, profundamente afetada pela hibridização. Além disso, verificou-se que o efeito da hibridização ´e mais intenso nas regiões dos pontos de sela, nas quais o gap supercondutor ´e máximo devido à simetria dx2−y2 . Com isso, a temperatura crítica de transiçãoo (Tc) do estado normal para o estado supercondutor, também é afetada pela hibridização. Os resultados sugerem também, que no caso de dopagem por buracos, a hibridização interfere no valor de dopagem em que ocorre a mudança no sinal do coeficiente Hall, portanto deve afetar também as propriedades de transportes do sistema. No caso de dopagem por elétrons, não foi verificado nenhuma mudança na natureza da superf´ıcie de Fermi. No entanto, como a hibridização aumenta a largura das bandas e dimimui a densidade de estados no nível de Fermi, neste caso a supercondutividade também é afetada. A topologia da superfície de Fermi nos regimes de dopagen por buracos e por elétrons concorda bem com resultados experimentais de ARPES obtidos recentemente para o composto La2−xSrxCuO4 (dopado por buracos) e para o composto Nd2−xCexCuO4 (dopado por elétrons).

Made available in DSpace on 2014-06-11T19:29:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-06-23Bitstream added on 2014-06-13T20:39:21Z : No. of bitstreams: 1 mota_jan_me_ilha.pdf: 251974 bytes, checksum: 6b15f7bfd8cf4d26aabd50365c86450f (MD5) / Universidade Estadual Paulista (UNESP) / Este trabalho foi desenvolvido com o objetivo de verificar o progresso com seleção recorrente nos Compostos Flintisa e Dentado, além da potencialidade dos mesmos para um possível uso como variedades comerciais. Observou-se que os rendimentos médios dos melhores ciclos de seleção do Flintisa e do Dentado equipararam-se com as melhores cultivares comerciais, apresentando rendimento de 5,5 t/ha e 5,3 t/ha na condição de baixa tecnologia e 7,3 t/ha e 7,7 t/ha na condição de alta tecnologia, respectivamente. O ganho com seleção para menor altura de espigas foi quantificado em um decréscimo de 1,2% ao longo de doze ciclos seletivos no Flintisa e 11,9% ao longo dos quatro últimos ciclos seletivos no Dentado, na avaliação conjunta dos ambientes de alta e baixa tecnologia. Ao longo de todo o processo seletivo houve uma resposta correlacionada de -4,1%/ciclo no acamamento do Flintisa na avaliação em baixa tecnologia e de -5,2%/ciclo no Dentado em alta tecnologia. Os resultados indicam que a seleção foi eficiente em aumentar o rendimento e diminuir a altura de espigas quando o processo seletivo foi voltado especificamente para esses caracteres. A continuidade do programa deve ter como base a seleção entre progênies para REND e AE conjuntamente nos próximos ciclos, em ambos os compostos. / This research was developed aiming to verify the progress after recurrent selection in Flintisa and Dentado Composite of maize, as well as the potentiality of the same population for a possible commercial use. It was observed that grain yield representing the best cycles of selection of Flintisa and Dentado (5.5 and 5.3 t/ha, in low technology; and 7.3 and 7.7 t/ha in high technology, respectively) were compared with the best commercial cultivars. The effect of selection on ear height resulted an average decrease of 1.2% after 12 cycles in Flintisa and 11.9% after four cycles in Dentado, evaluated under low and high technology. Along the selective process, the correlated responses for plant lodging were -4.1% per cycle for Flintisa in low technology and -5.2% per cycle in Dentado in high technology. The overall results indicated that selection was effective to increase grain yield and reduce ear height when the selection process was directed specifically for each trait. The continuity of the program shell is based on selection among progenies simultaneously for higher grain yield and lower ear height.

Orientador: Eduardo Miranda / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-16T08:19:56Z (GMT). No. of bitstreams: 1 Andrade_EricdeCastroe_D.pdf: 5537554 bytes, checksum: 1391d5fcc710b5e471f0814a4a6d484f (MD5) Previous issue date: 2010 / Resumo: Sistemas eletrônicos fortemente correlacionados desordenados possuem dois mecanismos básicos para a localização eletrônica e a subsequente destruição do estado metálico: o de Mott (causado pela interação elétron-elétron) e o de Anderson (causado pela desordem). Nesta tese, estudamos como estes mecanismos competem dentro da fase metálica e também como afetam o comportamento crítico do sistema, empregando uma generalização para o caso desordenado do cenário de Brinkman-Rice para a transição de Mott. Investigamos os efeitos de desordem fraca e moderada sobre a transição metal-isolante de Mott a T = 0 em duas dimensões. Para desordem sucientemente baixa, a transição mantém sua característica do tipo Mott, na qual temos os pesos de quasipartícula Zi indo a zero na transição e uma forte blindagem da desordem na região crítica. Em contraste com o comportamento encontrado para d = 8 , no nosso caso as flutuações espaciais dos pesos de quasipartícula são fortemente amplificadas próximo à transição de Mott de tal forma que eles adquirem uma distribuição do tipo lei de potência P (Z) ~ Z a-1 ,com a --> 0 na transição. Tal comportamento altera completamente as características desta transição com relação ao caso limpo, e é um indício robusto da emergência de uma fase de Griffiths eletrônica precedendo a transição metal-isolante de Mott, com uma fenomenologia surpreendentemente similar àquela do "ponto fixo de desordem infinita" encontrada em magnetos quânticos. Uma consequência imediata dessas novas características introduzidas pela desordem é que estados eletrônicos próximos à superfície de Fermi tornam-se mais homogêneos na região crítica, ao passo que estados com maiores energias têm o comportamento oposto: eles apresentam uma grande inomogeneidade precisamente nas vizinhanças da transição de Mott. Sugerimos que uma desordem efetiva dependente da interação é uma característica comum a todos os sistemas de Mott desordenados. Estudamos também como os efeitos bem conhecidos das oscilações de longo alcance de Friedel são afetados por fortes correlações eletrônicas. Primeiramente, mostramos que sua amplitude e alcance são consideravelmente suprimidos em líquidos de Fermi fortemente renormalizados. Posteriormente, investigamos o papel dos espalhamentos elásticos e inelásticos na presença dessas oscilações. Em geral, nossos resultados analíticos mostram que um papel proeminente das oscilações de Friedel é relegado a sistemas fracamente interagentes. Abordamos, por m, os efeitos das interações sobre o isolante de Anderson em uma dimensão. Construímos a função de escala ß (g) e mostramos que a escala de "crossover" g *, que marca a transição entre o regime ôhmico e o localizado da condutância, é renormalizada pelas interações. Como consequência, embora não haja a emergência de estados verdadeiramente estendidos, o regime ôhmico de g estende-se agora por uma região consideravelmente maior do espaço de parâmetros. / Abstract: Disordered strongly correlated electronic systems have two basic routes towards localization underlying the destruction of the metallic state: the Mott route (driven by electron-electron interaction) and the Anderson route (driven by disorder). In this thesis, we study how these two mechanisms compete in the metallic phase, and also how they change the critical behavior of the system, within a generalization to the disordered case of the Brinkman-Rice scenario for the Mott transition. We investigate the effects of weak to moderate disorder on the Mott metal-insulator transition at T = 0 in two dimensions. For sufficiently weak disorder, the transition retains the Mott character, as signaled by the vanishing of the local quasiparticle weights Zi and strong disorder screening at criticality. In contrast to the behavior in d = 8, here the local spatial fluctuations of quasiparticle parameters are strongly enhanced in the critical regime, with a distribution function P(Z) ~ Z a-1 and a --> 0 at the transition. This behavior indicates the robust emergence of an electronic Griffiths phase preceding the MIT, in a fashion surprisingly reminiscent of the " Infinite Randomness Fixed Point" scenario for disordered quantum magnets. As an immediate consequence of these new features introduced by disorder, we have that the electronic states close to the Fermi energy become more spatially homogeneous in the critical region, whereas the higher energy states show the opposite behavior: they display enhanced spatial inhomogeneity precisely in the close vicinity to the Mott transition. We suggest that such energy-resolved disorder screening is a generic property of disordered Mott systems. We also study how well-known effects of the long-ranged Friedel oscillations are affected by strong electronic correlations. We first show that their range and amplitude are signifficantly suppressed in strongly renormalized Fermi liquids. We then investigate the interplay of elastic and inelastic scattering in the presence of these oscillations. In the singular case of two-dimensional systems, we show how the anomalous ballistic scattering rate is conned to a very restricted temperature range even for moderate correlations. In general, our analytical results indicate that a prominent role of Friedel oscillations is relegated to weakly interacting systems. Finally, we discuss the effects of correlations on the Anderson insulator in one dimension. We construct the scaling function ß(g) and we show that the crossover scaling g*, which marks the transition between the ohmic and the localized regimes of the conductance, is renormalized by the interactions. As a consequence, we show that, although truly extend states do not emerge, the ohmic regime covers now a considerably larger region in the parameter space. / Doutorado / Física da Matéria Condensada / Doutor em Ciências

Orientador: Michel Daoud Yacoub / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-07T10:47:15Z (GMT). No. of bitstreams: 1 Dias_UgoSilva_M.pdf: 1177515 bytes, checksum: fe2406aa04941e752532e2773393c0cd (MD5) Previous issue date: 2006 / Resumo: Esta dissertação analisa e valida, através de medidas de campo, estatísticas de ordem superior para canais com desvanecimento Weibull e Nakagarni-m. Considerando canais com desvanecimento Weibull, devido à ausência de um modelo físico, estatísticas conjuntas de duas variáveis Weibull correlacionadas foram obtidas em forma fechada e em função de parâmetros físicos bem conhecidos, se destacando as funções de autocorrelação e espectro de potência. Analisando canais com desvanecimento Nakagami-m, expressões simples e em forma fechada para as funções de autocorrelação e espectro de potência foram derivadas. Medidas de campo indoor e outdoor foram realizadas por meio de um sistema montado e configurado especialmente para investigar as estatísticas em estudo. Foram observados excelentes ajustes entre os dados teóricos e experimentais. Os resultados das medições validam as funções de autocorrelação e espectro de potência para envoltórias Weibull e Nakagarni-m / Abstract: This dissertation analyzes and validates, through field trials, higher order statistics for Weibull and Nakagarni-m fading channels. Conceming Weibull fading channels, due to the absence of a physical model related to such channels, joint statistics for two correlated Weibull variables were obtained in closed-form and in terms of well-known physical parameters, in particular the autocorrelation and power spectrum functions. Conceming Nakagarni-m fading channels, simple and closed-form expressions for autocorrelation and power spectrum functions were derived; Indoor and outdoor field trial measurements were conducted in order to investigate these statistics. The mobile reception equipment was especially assembled for this purpose. Excellent fits between analytical and empirical metrics were observed. The measurements results validate the autocorrelation and power spectrum functions of the Weibull and Nakagami-m fading channels / Mestrado / Telecomunicações e Telemática / Mestre em Engenharia Elétrica

O objetivo principal deste trabalho é introduzir os modelos log-Birnbaum-Saunders mistos (log-BS mistos) e estender os resultados para os modelos log-Birnbaum-Saunders t-Student mistos (log-BS-t mistos). Os modelos log-BS são bastante conhecidos desde o trabalho de Rieck e Nedelman (1991) e particularmente receberam uma grande atenção nos últimos 10 anos com vários trabalhos publicados em periódicos internacionais. Contudo, o enfoque desses trabalhos tem sido em modelos log-BS ou log-BS generalizados com efeitos fixos, não havendo muita atenção para modelos com efeitos aleatórios. Inicialmente, apresentamos no trabalho uma revisão das distribuições Birnbaum-Saunders e Birnbaum-Saunders generalizada (BSG) e em seguida discutimos os modelos log-BS e log-BS-t com efeitos fixos, para os quais revisamos alguns resultados de estimação e diagnóstico. Os modelos log-BS mistos são então apresentados precedidos de uma revisão dos métodos de quadratura de Gauss Hermite (QGH). Embora a estimação dos parâmetros nos modelos log-BS mistos seja efetuada através do procedimento Proc NLMIXED do SAS (Littell et al, 1996), aplicamos o método de quadratura não adaptativa a fim de obtermos aproximações para o logaritmo da função de verossimilhança do modelo log-BS de intercepto aleatório. Com essas aproximações derivamos as funções escore e a matriz hessiana, além das curvaturas normais de influência local (Cook, 1986) para alguns esquemas de perturbação usuais. Os mesmos procedimentos são aplicados para os modelos log-BS-t de intercepto aleatório. Discussões sobre a predição dos efeitos aleatórios, teste para o componente de variância dos modelos com intercepto aleatório e análises de resíduos são também apresentados. Finalmente, comparamos os ajustes de modelos log-BS e log-BS mistos a um conjunto de dados reais. Métodos de diagnóstico são utilizados na comparação dos modelos ajustados. / The aim of this work is to introduce the log-Birnbaum-Saunders mixed models (log-BS mixed models) and to extend the results to log-Birnbaum-Saunders Student-t mixed models (log-BS-t mixed models). The log-BS models are well-known since the work by Rieck and Nedelman (1991) and particularly have received great attention in the last 10 years with various published papers in international journals. However, the emphasis given in such works has been in fixed-effects models with few attention given to random-effects models. Firstly, we present in this work a review on Birnbaum-Saunders and generalized Birnbaum-Saunders distributions and so we discuss log-BS and log-BS-t fixed-effects models for which some results on estimation and diagnostic are presented. Then, we introduce the log-BS mixed models preceded by a review on Gauss-Hermite quadrature. Although the parameter estimation of the marginal log-BS and log-BS-t mixed models are performed in the procedure NLMIXED of SAS (Littell et al., 1996), we apply the quadrature methods in order to obtain approximations for the likelihood function of the log-BS and log-BS-t random intercept models. These approximations are used to derive the respective score functions, observed information matrices as well as the normal curvature of local influence (Cook, 1986) under some usual perturbation schemes. Discussions on the prediction of the random effects, variance component tests and residual analysis are also given. Finally, we compare the fits of log-BS and log-BS-t mixed models to a real data set. Diagnostic methods are used in the comparisons.