L'estimation de crues de projet est requise pour le dimensionnement de barrages et de bassins de rétention, de même que pour la gestion des inondations lors de l’élaboration de cartes d’aléas ou lors de la modélisation et délimitation de plaines d’inondation. Généralement, les crues de projet sont définies par leur débit de pointe à partir d’une analyse fréquentielle univariée. Cependant, lorsque le dimensionnement d’ouvrages hydrauliques ou la gestion de crues nécessitent un stockage du volume ruisselé, il est également nécessaire de connaître les caractéristiques volume, durée et forme de l’hydrogramme de crue en plus de son débit maximum. Une analyse fréquentielle bivariée permet une estimation conjointe du débit de pointe et du volume de l’hydrogramme en tenant compte de leur corrélation. Bien qu’une telle approche permette la détermination du couple débit/volume de crue, il manque l’information relative à la forme de l’hydrogramme de crue. Une approche attrayante pour caractériser la forme de la crue de projet est de définir un hydrogramme représentatif normalisé par une densité de probabilité. La combinaison d’une densité de probabilité et des quantiles bivariés débit/volume permet la construction d’un hydrogramme synthétique de crue pour une période de retour donnée, qui modélise le pic d’une crue ainsi que sa forme. De tels hydrogrammes synthétiques sont potentiellement utiles et simples d’utilisation pour la détermination de crues de projet. Cependant, ils possèdent actuellement plusieurs limitations. Premièrement, ils reposent sur la définition d’une période de retour bivariée qui n’est pas univoque. Deuxièmement, ils décrivent en général le comportement spécifique d’un bassin versant en ne tenant pas compte de la variabilité des processus représentée par différents types de crues. Troisièmement, les hydrogrammes synthétiques ne sont pas disponibles pour les bassins versant non jaugés et une estimation de leurs incertitudes n’est pas calculée.Pour remédier à ces manquements, cette thèse propose des avenues pour la construction d’hydrogrammes synthétiques de projet pour les bassins versants jaugés et non jaugés, de même que pour la prise en compte de la diversité des types de crue. Des méthodes sont également développées pour la construction d’hydrogrammes synthétiques de crue spécifiques au bassin et aux événements ainsi que pour la régionalisation des hydrogrammes. Une estimation des diverses sources d’incertitude est également proposée. Ces travaux de recherche montrent que les hydrogrammes synthétiques de projet constituent une approche qui s’adapte bien à la représentation de différents types de crue ou d’événements dans un contexte de détermination de crues de projet. Une comparaison de différentes méthodes de régionalisation montre que les hydrogrammes synthétiques de projet spécifiques au bassin peuvent être régionalisés à des bassins non jaugés à l’aide de méthodes de régression linéaires et non linéaires. Il est également montré que les hydrogrammes de projet spécifiques aux événements peuvent être régionalisés à l’aide d’une approche d’indice de crue bivariée. Dans ce contexte, une représentation fonctionnelle de la forme des hydrogrammes constitue un moyen judicieux pour la délimitation de régions ayant un comportement hydrologique de crue similaire en terme de réactivité. Une analyse de l’incertitude a montré que la longueur de la série de mesures et le choix de la stratégie d’échantillonnage constituent les principales sources d’incertitude dans la construction d’hydrogrammes synthétiques de projet. Cette thèse démontre qu’une approche de crues de projet basée sur un ensemble de crues permet la prise en compte des différents types de crue et de divers processus. Ces travaux permettent de passer de l’analyse fréquentielle statistique de crues vers l’analyse fréquentielle hydrologique de crues permettant de prendre en compte les processus et conduisant à une prise de décision plus éclairée. / Design flood estimates are needed in hydraulic design for the construction of dams and retention basins and in flood management for drawing hazard maps or modeling inundation areas. Traditionally, such design floods have been expressed in terms of peak discharge estimated in a univariate flood frequency analysis. However, design or flood management tasks involving storage, in addition to peak discharge, also require information on hydrograph volume, duration, and shape . A bivariate flood frequency analysis allows the joint estimation of peak discharge and hydrograph volume and the consideration of their dependence. While such bivariate design quantiles describe the magnitude of a design flood, they lack information on its shape. An attractive way of modeling the whole shape of a design flood is to express a representative normalized hydrograph shape as a probability density function. The combination of such a probability density function with bivariate design quantiles allows the construction of a synthetic design hydrograph for a certain return period which describes the magnitude of a flood along with its shape. Such synthetic design hydrographs have the potential to be a useful and simple tool in design flood estimation. However, they currently have some limitations. First, they rely on the definition of a bivariate return period which is not uniquely defined. Second, they usually describe the specific behavior of a catchment and do not express process variability represented by different flood types. Third, they are neither available for ungauged catchments nor are they usually provided together with an uncertainty estimate.This thesis therefore explores possibilities for the construction of synthetic design hydrographs in gauged and ungauged catchments and ways of representing process variability in design flood construction. It proposes tools for both catchment- and flood-type specific design hydrograph construction and regionalization and for the assessment of their uncertainty.The thesis shows that synthetic design hydrographs are a flexible tool allowing for the consideration of different flood or event types in design flood estimation. A comparison of different regionalization methods, including spatial, similarity, and proximity based approaches, showed that catchment-specific design hydrographs can be best regionalized to ungauged catchments using linear and nonlinear regression methods. It was further shown that event-type specific design hydrograph sets can be regionalized using a bivariate index flood approach. In such a setting, a functional representation of hydrograph shapes was found to be a useful tool for the delineation of regions with similar flood reactivities.An uncertainty assessment showed that the record length and the choice of the sampling strategy are major uncertainty sources in the construction of synthetic design hydrographs and that this uncertainty propagates through the regionalization process.This thesis highlights that an ensemble-based design flood approach allows for the consideration of different flood types and runoff processes. This is a step from flood frequency statistics to flood frequency hydrology which allows better-informed decision making.

Les océans subissent des pressions d'origine anthropique particulièrement fortes comme la surpêche, la pollution physico-chimique, et le bruit rayonné par les activités industrielles et militaires. Cette thèse se place dans un contexte de compréhension de l'impact du bruit rayonné dans les océans sur les mammifères marins. L'acoustique passive joue donc un rôle fondamental dans ce problème. Ce travail aborde la tâche de détection de signatures acoustiques de mammifères marins dans le spectrogramme. Cette tâche est difficile pour deux raisons : 1. le bruit océanique a une structure complexe (non-stationnaire, coloré), 2. les signaux de mammifères marins sont inconnus et possèdent eux aussi une structure complexe (non-stationnaires bande étroite et/ou impulsionnels). Le problème doit donc être résolu de manière locale en temps-fréquence, et ne pas faire d'hypothèse a priori sur le signal. Des détecteurs statistiques basés uniquement sur la connaissance des statistiques du bruit dans le spectrogramme existent, mais souffrent deux lacunes : 1. leurs performances en terme de probabilité de fausse alarme/ probabilité de détection se dégradent fortement à faible rapport signal à bruit, et 2. ils ne sont pas capables de séparer les signaux à bande étroite des signaux impulsionnels. Ce travail apporte des pistes de réflexion sur ces problèmes.L'originalité de ce travail de thèse repose dans la formulation d'un test d'hypothèse binaire prenant explicitement en compte l'organisation spatiale des pics temps-fréquence. Nous introduisons une méthode d'Analyse de la Densité des Fausses Alarmes (FADA) qui permet de discriminer les régions temps-fréquence abritant le signal de celles n'abritant que du bruit. Plus précisément,le nombre de fausses alarmes dans une région du plan est d'abord modélisé par une loi binomiale, puis par une loi binomiale corrélée, afin de prendre en considération la redondance du spectrogramme. Le test d'hypothèse binaire est résolu par une approche de Neyman-Pearson. Nous démontrons numériquement la pertinence de cette approche et nous la validons sur données réelles de mammifères marins disposant d'une grande variété de signaux et de conditions de bruit. En particulier, nous illustrons la capacité de FADA à discriminer efficacement le signal du bruit en milieu fortement impulsionnel. / The oceans experience heavy anthropogenic pressure due to overfishing, physico-chemical pollution, and noise radiated by industrial and military activities. This work focuses on the use of passive acoustic monitoring of the oceans, as a tool to understand the impact of radiated noise on marine ecosystems, and particularly on marine mammals. This work tackles the task of detection of acoustical signals of marine mammals using the spectrogram. This task is uneasy for two reasons : 1. the ocean noise structure is complex (non-stationary and colored) and 2. the signals of interest are unknown and also shows a complex structure (non-stationary narrow band and/or impulsive). The problem therefore must be solved locally without making a priori hypothesis on the signal. Statistical detectors only based on the local analysis of the noise spectrogram coefficients are available, making them suitable for this problem. However, these detectors suffer two disadvantages : 1. the trade-offs false alarm probability/ detection probability that are available for low signal tonoise ratio are not satisfactory and 2. the separation between narrow-band and impulsive signals is not possible. This work brings some answers to these problems.The main contribution of this work is to formulate a binary hypothesis test taking explicitly in account the spatial organization of time-frequency peaks. We introduce the False Alarm Density Analysis (FADA) framework that efficiently discriminates time-frequency regions hosting signal from the ones hosting noise only. In particular the number of false alarms in regions of the binary spectrogram is first modeled by a binomial distribution, and then by a correlated binomial distribution to take in account the spectrogram redundancy. The binary hypothesis test is solved using a Neyman-Pearson criterion.We demonstrate the relevance of this approach on simulated data and validate the FADA detector on a wide variety of real signals. In particular we show the capability of the proposed method to efficiently detect signals in highly impulsive environment.

This study aimed at describing the characteristics of daily precipitation and discharge extremes in the Adige river basin at the city of Trento. Annual maximum series for the period 1975−2014 were analyzed in terms of trends, seasonality indices and L-moments. A Mann-Kendall trend analysis showed a weak but significant signal of decreasing ex-tremes; the percentages of sites with significant negative trends were overall larger than the significance levels. Precipitation extremes were characterized primarily by autumn storms, while floods had a stronger seasonality with peaks occurring predominantly in June and July which indicated that the timing not solely explained by rainfall maxima. The Adige basin was found to be a homogenous region with respect to precipitation, but the results did not support a corresponding assumption for discharge. A regional fre-quency analysis was performed for precipitation data and found both the Pearson type III and generalized normal distributions to be adequate regional frequency distributions. The extreme daily precipitation at Trento with a 100-year return period was estimated to be between 114 and 148 mm/d. / Egenskaperna hos extremvärden av dygnsnederbörd och -vattenföring i Adigeflodens av-rinningsområde vid staden Trento undersöktes. Serier med årsmaxima för perioden 1975–2014 analyserades med avseende på trender, säsongsindex och L-moment. Trendanalys med Mann-Kendallmetod antydde en svag men signifikant signal om minskande extrem-värden, då andelen mätstationer med signifikant negativa trender överlag var större än signifikansnivån. Den extrema nederbörden karakteriserades huvudsakligen av höststor-mar, medan vattenföringen hade en starkare säsongsbundenhet då maxima inträffade främst under juni och juli. Vattenföringens extremvärden kunde därmed inte enbart för-klaras av nederbördsmaxima. Avrinningsområdet kunde betraktas som en homogen reg-ion för nederbörd, men resultaten gav inte stöd åt ett motsvarande antagande för vatten-föring. En regional frekvensanalys genomfördes för nederbördsdata och visade att Pear-son typ III och den generaliserade normalfördelningen var lämpliga regionala sannolik-hetsfördelningar. Över Trento uppskattades den extrema dygnsnederbörden med en åter-komstperiod på 100 år till mellan 114 och 148 mm/d.

Em nível microscópico, as rochas apresentam microdefeitos que agem como concentradores locais de tensão, favorecendo a ocorrência de ruptura frágil. O entendimento desse processo requer análises experimentais em rochas submetidas a tensões de tração. O ensaio de compressão diametral é uma alternativa apropriada, pois não apresenta as dificuldades envolvidas no ensaio de tração direta. A propagação de microfissuramento em materiais frágeis produz liberação de energia na forma de ondas elásticas chamadas de emissões acústicas (EA). O monitoramento com EA permite acompanhar a propagação de dano no corpo de prova (CP), sem perturbá-lo. Nesta pesquisa, CPs de mármore e monzogranito são submetidos a ensaios de compressão diametral com deslocamentos monotônicos e cíclicos, com controle de deslocamento. Aplica-se a técnica de EA, em conjunto com análises petrográficas, análises das curvas de força versus deslocamento e exame visual, para caracterizar o seu processo de microfissuramento. A localização tridimensional das fontes de EA foi realizada inicialmente utilizando-se o software AEwin® da PASA. Foi desenvolvido um programa de localização aprimorado que incorpora o cálculo da velocidade de propagação das ondas (vp) média para cada instante em que uma fonte é localizada. O novo programa (Crack Location by Acoustic emission with P Wave Velocity determination, CLAPWaVe) mostra um claro decréscimo da velocidade de propagação com o aumento do dano. O programa desenvolvido (CLAPWaVe) mostrou melhor ajuste e maior coerência com a literatura e com a condição final rompida dos CPs do que o software AEwin. Em mármore e monzogranito o microfissuramento se inicia a 25-30% e 75-85% do carregamento de pico, respectivamente, e localiza-se na vizinhança do centro do CP. Em ambas as rochas se acumulou, também, dano na região dos apoios do CP, associado à transferência de carregamento do berço ao CP. Antes do pico de carregamento, o microfissuramento tornou-se mais denso e localizado no centro e nos apoios do CP, embora a região central ainda concentre a maior parte. Após o pico, o microfissuramento acumulou-se em uma das faces do CP, progredindo até a outra face. O monzogranito apresentou ruptura progressiva do CP, enquanto que no mármore a maior parte da superfície de ruptura já está desenvolvida imediatamente após o pico. Durante o ensaio em ambas as rochas, no núcleo central foram registradas as menores velocidades vp do CP. Na região dos apoios, embora tenha havido microfissuramento, registraram-se as maiores velocidades vp no CP, pois o confinamento produzido pelo contato com o berço aumentou localmente a rigidez do CP. A distribuição não homogênea de vp no CP revelou que a consideração desse parâmetro como constante e igual à condição intacta ao longo do ensaio, como comumente encontrado na literatura, não representa a condição real do CP danificado. O microfissuramento no monzogranito se propaga principalmente através dos cristais de quartzo, seguindo um caminho tortuoso subparalelo à direção de carregamento e liberando altos níveis de energia absoluta. No mármore, a propagação segue os planos de clivagem da calcita, liberando níveis baixos de energia absoluta. Os histogramas da distribuição espacial da resistência em ambas as rochas mostraram bom ajuste a uma distribuição de Weibull, porém o monzogranito mostrou melhor ajuste e menor variabilidade que o mármore. As análises dos sinais no domínio das frequências mostraram que o microfissuramento é caracterizado por emissões de banda larga. / At microscopic level, rocks exhibit microflaws, which act as local stress concentrators, favoring the occurrence of brittle failure. The understanding of this process requires experimental analyses of rock specimens under tensile stresses. The diametral compression test is an adequate alternative for such a studies, because it does not present the difficulties of direct tension tests. Crack propagation in brittle materials releases energy as transient elastic waves known as acoustic emission (AE). Monitoring with AE enables an insight into the cracking process without affecting the integrity of the sample. In this work, marble and monzogranite specimens were subjected to monotonic and cyclic displacementcontrolled diametral compression tests. The AE monitoring technique was applied in conjunction with petrographic analyses, interpretation of the load versus displacement curves and visual examination of the samples for the characterization of their cracking process. The three-dimensional localization of the AE sources was initially carried out by using the software AEwin® from PASA. An improved localization software, which considers the P-wave velocity variation along the damage process (vp) for each AE source was developed. The developed software (Crack Location by Acoustic emission with P Wave Velocity determination, CLAPWaVe) has shown greater consistency with literature and the final cracked samples and better accuracy than AEwin. Microcracking in monzogranite and marble initiated at 25-30% and 75-80% of the peak load, respectively, and is located at the center of the specimen. In addition, both rocks showed concentrated microcracking close to the region of contact between the specimen and the loading platens, related to the loading transference along the loading edge. Before peak load, microcracking becomes denser and localized at the center and the contact region of the specimen, although, the central region still concentrates the main portion of the damage. After the peak load, new microcracks were first concentrated on one of the faces at the center of the specimen and then propagated through its thickness all the way to the other face. The progressive failure in monzogranite extended through to the end of the test, while in marble the main portion of the failure surface of the specimen developed just after peak. During the whole test in both rocks, the lowest velocities (vp) of the specimen were recorded in the central core. Although microcracking was induced at the contact region, the highest velocities vp of the specimen were registered there, because of the confinement effect produced by the platens, which lead to a local increase in the stiffness of the specimen. The non-homogeneous distribution of vp in the specimen has revealed that the utilization of this parameter as a constant and equal to the value measured in the specimen before testing (as usually adopted in the literature), does not represent the real condition of the damaged specimen. In monzogranite, microcracks propagate mainly through quartz crystals, following a tortuous path subparallel to the loading direction, by releasing high-level of absolute energy, while in marble the propagation of microcracks follows the cleavage planes of calcite, by releasing low-level of absolute energy. The histograms of spatial strength distribution in both rocks have shown good adjustment to a Weibull distribution, but monzogranite exhibited a more accurate adjustment with lower variability than marble. The analysis of signals in the frequency domain showed that the microcracking is characterized by wide band emissions.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-02-16T09:52:46Z No. of bitstreams: 1 alamsilvamenezes.pdf: 8301590 bytes, checksum: aed618e30f38206da4bf4f329924f87e (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-02-26T12:30:53Z (GMT) No. of bitstreams: 1 alamsilvamenezes.pdf: 8301590 bytes, checksum: aed618e30f38206da4bf4f329924f87e (MD5) / Made available in DSpace on 2016-02-26T12:30:53Z (GMT). No. of bitstreams: 1 alamsilvamenezes.pdf: 8301590 bytes, checksum: aed618e30f38206da4bf4f329924f87e (MD5) Previous issue date: 2014-09-01 / A presente tese propõe soluções ao problema da explicitação do conteúdo espectral de processos estacionários e não estacionários, com aplicações na estimação de frequência, estimação da densidade espectral de potência e no monitoramento do espectro. A técnica de estimação de frequência proposta nesta tese, baseada na warped discrete Fourier transform, apresenta, de acordo com as simulações computacionais, o melhor desempenho frente às demais técnicas comparadas, atingindo o Cramer-Rao bound para uma ampla faixa de relação sinal ruído. Em relação a estimação da densidade espectral de potência, a Hartley Multitaper method, proposta nesta tese, apresenta desempenho similar à multitaper method, em termos da variância de estimação e da polarização do espectro, mas simpli cação de implementação. Uma técnica para monitoramento do espectro para sistemas power line communication é proposta, levando em consideração o conceito de quanta e a diversidade observada quando os sinais são aquisitados a partir da rede de energia elétrica e do ar. Baseando-se em sinais sintéticos, gerados em computador, assim como dados de medição do espectro, obtidos utilizando uma antena e o cabo de energia elétrica como elementos sensores, veri fica-se que o desempenho da técnica proposta supera a monitoração padrão, sobretudo quando a diversidade gerada pelo cabo e pela antena sobre o sinal monitorado é explorada na detecção. / This dissertation aims at discussing solutions to deal with spectral analysis of stationary and non-stationary processes for frequency estimation, power spectral density estimation and spectral monitoring applications. The frequency estimation techniques are assessed through computer simulations. The proposed technique for frequency estimation is based on warped discrete Fourier transform outperforms other techniques, achieving the Cramer-Rao Bound for a wide range of signal to noise ratio. Regarding the power spectral density estimation, the proposed Hartley Multitaper Method shows similar performance, in terms of variance of estimates and polarization spectrum; however, it can simplify the implementation complexity. The introduced spectrum sensing technique is based on quanta de nition and the diversity o ered by the signals acquired from the electric power grids and the air. Based on computer-generation data and those one obtained during a measurement campaign, which one in this thesis is evaluated using synthetic signals, generated by computer, as well as measurement data of the spectrum. The numerical results show that the proposed technique outperforms a previous technique and can attain the very detection ratio and the very low false alarm when the diversity yielded by electric power grid and air is exploited.

O presente estudo teve por objetivo avaliar por meio da análise de freqüência de ressonância (AFR) o efeito da irradiação com laser de GaAlAs na estabilidade de implantes de titânio, como cociente de estabilidade do implante (ISQ) instalados em pacientes parcialmente edentados na região posterior da mandíbula; assim como avaliar a evolução da estabilidade dos implantes, durante o período de osseointegração. Foram selecionados 8 pacientes adultos, com boa saúde para a instalação cirúrgica de 30 implantes Xive S® (Dentsply). Portanto, foram instalados de 2 a 5 implantes por paciente, distribuídos bilateralmente. Cada paciente atuou como seu próprio controle. Os implantes do lado controle não foram irradiados, e os do lado experimental foram submetidos a terapia com laser de diodo GaAlAs com ?= 830 nm, densidade de energia de 8 j/cm2, potência de 100 mW, modo contínuo, de forma pontual em 20 pontos, durante 3 segundos por ponto. A primeira sessão de irradiação foi no pós-operatório imediato, sendo repetida a cada 48 horas nos primeiros 14 dias, totalizando 7 irradiações. Após a instalação dos implantes foi medida a estabilidade primária destes com o aparelho Osstell?. Novas medidas de ISQ foram realizadas após 10 dias, e 3, 6, 9 e 12 semanas. No momento da instalação, os valores de ISQ na região posterior da mandíbula oscilaram de 65-84 com média de 76, sofrendo queda significativa da estabilidade do 100 dia para a 6a semana no grupo irradiado e apresentando um aumento gradual a partir da 6a semana até a 12a semana. Os valores mais altos de ISQ foram observados no 100 dia no grupo irradiado, embora sem significância estatística, e os mais baixos foram observados na 6a semana em ambos os grupos. Não foi evidenciado o efeito do laser de GaAlAs na estabilidade dos implantes com o aparelho OsstellTM, porém não se pode afirmar que os padrões de reparação óssea e a taxa de osseointegração entre os implantes irradiados e não irradiados tenham sido similares. / JThe present study was carried out to evaluate the effect of irradiation with the GaALAs laser in the stability of titanium implants (ISQ), inserted in partially edentulous patients, by means of resonance frequency analysis (RFA); as well as to evaluate the evolution of the stability during the osseointegration processs. A group of 8 patients were seleted for the insertion of 30 implants (Xive S® - Dentsply). The implants in the control site were not irradiated, and the implants in the experimentall site were submitted to laser therapy with a GaAlAs with ?= 830 nm, energy density of 8 j/cm2, power of 100 mW, continuing mode, in 20 points, for 3 seconds per point. The first irradiation was immediately after the surgery, and it was repeated every 48 hours in the first 14 days, totalizing 7 irradiations. After the implants insertion, the primary stability was measured using Osstell?. New measurements were carried out after 10 days, 3, 6, 9, 12 weeks. The incial ISQ values ranged from 65-84, with a mean of 76, showing a significative decrease in the stability from the 10th day to the 6th weeks in the irradiated group, and showing a gradual increase from 6th to 12th week. The highest ISQ values were observed in the 10th day in the irradiated group, and the lower ISQ values were observed in the 6th week in both groups. The effect of the irradiation with GaAlAs laser in implant stability was not evicenced; however, it can not be affirmed that irradiated and not irradiated implants have similar bone repair patterns and osseointegration rates.

Les parties tournantes des turbomachines aéronautiques sont composées d’une succession de roues aubagées qui permettent le transfert de l’énergie entre l’air et le rotor. Ces roues aubagées constituent des pièces particulièrement sensibles car elles doivent répondre en termes de dimensionnement à des impératifs de performances aérodynamiques, d’aéroacoustique et de tenue mécanique à la rotation,à la température et à la charge aérodynamique. Le contact avec frottement existant au niveau des attaches aube-disque joue un rôle important sur les niveaux vibratoires.Ce travail porte sur l’étude de l’usure par fretting sous chargements dynamiques dans les interfaces frottantes. En effet, les vibrations de l’aube peuvent produire des micro-glissements en pied d’aubequi peuvent entraîner un phénomène d’usure par fretting. Les connaissances sur le comportement de l’usure sous sollicitations dynamiques sont faibles. Seuls existent des outils numériques pour modéliser l’usure dans le cas de sollicitations quasi-statiques. Nous proposons dans cette thèse des méthodes pour calculer l’évolution de l’usure au cours des cycles de chargement dynamique basées sur une approche multi-échelle en temps. La réponse vibratoire de la structure est liée à une échelle de temps rapide qui est calculée par une méthode d’équilibrage harmonique, dans laquelle les déplacements et les efforts sont projetés sur la base de Fourier. Différentes approches temps-fréquence de calcul des coefficients de Fourier des forces de contact sont présentées. La cinétique d’usure est liée à une échelle lente et différentes méthodes sont proposées pour l’intégrer. La prise en compte des géométries usées dans le modèle éléments finis se fait par l’ajout d’un vecteur des profondeurs d’usure dans le terme de pénalité des lagrangiens dynamiques. Des exemples académiques valident et illustrent les méthodes proposées. Ces méthodes sont ensuite appliquées à l’étude de l’usure par fretting en pied d’aube de soufflante. L’étude numérique met en lumière le couplage entre vibration et usure par fretting aux interfaces de contact. La modification du comportement dynamique global de la roue aubagée est aussi observée. / The rotating parts of aeronautical turbomachineries are made of bladed disks which enable the transfer of energy from the air to the rotor. These bladed disks are especially critical parts because their dimensioning has to meet strict requirements in terms of aerodynamical performance, aeroacoustics and mechanical resistance to rotation, temperature and aerodynamical loads. The frictional contact at the interface between blade and disk has an important influence on the vibratory levels.This work deals with the study of fretting-wear in frictional interfaces under dynamical loading. Indeed,the blade’s vibrations can produce micro-slidings in blade’s root which may entail fretting-wear. Wear under dynamical loading is a badly known phenomenon. Numerical tools exist for quasic-static conditions only. Here,methods are proposed to quantify the evolution of wear along dynamical loadingcycles based on a time-multiscale approach. The vibratory response of the structure is linked with a fasttime scale which is calculated by a harmonic balance method : displacements and forces are expressed through Fourier series. Different frequency-time approaches are presented to compute the Fourier coefficients of contact forces. Wear kinetics is linked with a slow time scale and different methods are proposed to integrate it.Worn geometries are taken into account in the finite elements model by a wear depth vector included in the penalty term of dynamic lagrangians. Academic examples validate and illustrate the proposed methods. These methods are then used to study fretting-wear in a fan’s bladeroot. The numerical results highlight the coupling between vibration and fretting-wear in frictional interfaces.The modification of the global dynamical behaviour of the bladed disk is also observed.

<p>Хидролошке&nbsp; суше&nbsp; су&nbsp; сложена&nbsp; појава&nbsp; како&nbsp; у погледу&nbsp; фактора&nbsp; који&nbsp; је&nbsp;&nbsp; изазивају,&nbsp; тако&nbsp; и&nbsp; у погледу&nbsp; њеног&nbsp; утицаја&nbsp; на&nbsp; екосистем&nbsp; и друштво.&nbsp; У&nbsp; дисертацији&nbsp; је&nbsp; приказана предност&nbsp; анализе&nbsp; малих вода,&nbsp; односно хидролошких&nbsp; суша&nbsp; са&nbsp; две&nbsp; променљиве (дефицит&nbsp; и&nbsp; трајање),&nbsp; у&nbsp; односу&nbsp; на&nbsp; уобичајену анализу&nbsp; са&nbsp; једном&nbsp; вредношћу(најчешће минимални&nbsp; годишњи&nbsp; протицај).&nbsp; Резултати добијени&nbsp; статистичком&nbsp; анализом&nbsp; суша,&nbsp; које су&nbsp; издвојене&nbsp; методом&nbsp; прага&nbsp; недвосмислено су&nbsp; показали&nbsp; да&nbsp; имају већу&nbsp; применљивост&nbsp; у водопривреди&nbsp; него&nbsp; методе&nbsp; које&nbsp; користе стандардизоване&nbsp; индексе,&nbsp; јер&nbsp; дају&nbsp; конкретне вредности&nbsp; недостајућих&nbsp; количина воде (запремине&nbsp; дефицита&nbsp; суша)&nbsp; у&nbsp; односу&nbsp; на релативне&nbsp; вредности&nbsp; стандардизованих индекса.&nbsp; Метода&nbsp; прага&nbsp; је&nbsp; примењена&nbsp; на39 станица&nbsp; у&nbsp; сливу&nbsp; Велике&nbsp; Мораве&nbsp; за&nbsp; период 1960-2014,&nbsp; што&nbsp; до&nbsp; сад&nbsp; представља&nbsp; највећи узорак&nbsp; на&nbsp; којем&nbsp; је&nbsp; примењивана&nbsp; у&nbsp; Србији, било&nbsp; да&nbsp; се&nbsp; ради&nbsp; о&nbsp; анализи&nbsp; малих&nbsp; или еликих&nbsp; вода.&nbsp; Као&nbsp; праг&nbsp; за&nbsp; издвајање&nbsp; суша узета&nbsp; је вредност Q₉₀ ,&nbsp; јер&nbsp; је&nbsp; циљ&nbsp; био&nbsp; анализа просторних&nbsp; и временских&nbsp; карактеристика екстремних(великих)&nbsp; суша&nbsp; у&nbsp; сливу&nbsp; Велике Мораве.&nbsp; Избор&nbsp; прага&nbsp; утицао&nbsp; је&nbsp; и&nbsp; на&nbsp; избор методе&nbsp; парцијалних&nbsp; серија&nbsp; за&nbsp; статистичку анализу карактеристика суша. За одређивање параметра&nbsp; теоријских&nbsp; расподела&nbsp; коришћени су L-моменти&nbsp; који&nbsp; дају&nbsp; поузданије&nbsp; оцене параметара&nbsp; од&nbsp; обичних&nbsp; момената.&nbsp; У досадашњим&nbsp; радовима,&nbsp; који&nbsp; су&nbsp; анализирали хидролошке&nbsp; суше&nbsp; методом&nbsp; парцијалних серија,&nbsp; функција&nbsp; расподеле&nbsp; се&nbsp; унапред одабирала,&nbsp; а&nbsp; не&nbsp; на&nbsp; основу&nbsp; тестова сагласности&nbsp; и&nbsp; провере&nbsp; графика&nbsp; вероватноће,као&nbsp; што&nbsp; је&nbsp; урађено&nbsp; у&nbsp; овој&nbsp; дисертацији.&nbsp; За проверу&nbsp; сагласности&nbsp; годишњег&nbsp; максимума дефицита&nbsp; и&nbsp; трајања&nbsp; коришћени&nbsp; су&nbsp; тестови Колмогоров-Смирнов&nbsp; и&nbsp; Крамер&ndash;Мизес,&nbsp; на основу&nbsp; којих&nbsp; су&nbsp; изабране&nbsp; меродавне расподеле&nbsp; за&nbsp; прорачун&nbsp; суша&nbsp; различитих повратних&nbsp; периода&nbsp; на&nbsp; станицама,&nbsp; и&nbsp; обрнуто.С&nbsp; помоћу L-момент&nbsp; дијаграма(LC _s/LC_k )утврђена&nbsp; је&nbsp; хомогеност&nbsp; региона,&nbsp; у&nbsp; овом случају&nbsp; целог&nbsp; слива&nbsp; Велике&nbsp; Мораве,&nbsp; као&nbsp; и изабрана&nbsp; регионална&nbsp; расподела(P+W)&nbsp; за дефиците&nbsp; и&nbsp; трајање&nbsp; суше,&nbsp; на&nbsp; основу&nbsp; које&nbsp; су израчунати&nbsp; безразмерни&nbsp; квантили,&nbsp; који&nbsp; се могу&nbsp; користити&nbsp; за&nbsp; оцену&nbsp; суша великих повратних&nbsp; периода&nbsp; на&nbsp; хидролошки неизученим сливовима.</p> / <p>Hidrološke&nbsp; suše&nbsp; su&nbsp; složena&nbsp; pojava&nbsp; kako&nbsp; u pogledu&nbsp; faktora&nbsp; koji&nbsp; je&nbsp;&nbsp; izazivaju,&nbsp; tako&nbsp; i&nbsp; u pogledu&nbsp; njenog&nbsp; uticaja&nbsp; na&nbsp; ekosistem&nbsp; i društvo.&nbsp; U&nbsp; disertaciji&nbsp; je&nbsp; prikazana prednost&nbsp; analize&nbsp; malih voda,&nbsp; odnosno hidroloških&nbsp; suša&nbsp; sa&nbsp; dve&nbsp; promenljive (deficit&nbsp; i&nbsp; trajanje),&nbsp; u&nbsp; odnosu&nbsp; na&nbsp; uobičajenu analizu&nbsp; sa&nbsp; jednom&nbsp; vrednošću(najčešće minimalni&nbsp; godišnji&nbsp; proticaj).&nbsp; Rezultati dobijeni&nbsp; statističkom&nbsp; analizom&nbsp; suša,&nbsp; koje su&nbsp; izdvojene&nbsp; metodom&nbsp; praga&nbsp; nedvosmisleno su&nbsp; pokazali&nbsp; da&nbsp; imaju veću&nbsp; primenljivost&nbsp; u vodoprivredi&nbsp; nego&nbsp; metode&nbsp; koje&nbsp; koriste standardizovane&nbsp; indekse,&nbsp; jer&nbsp; daju&nbsp; konkretne vrednosti&nbsp; nedostajućih&nbsp; količina vode (zapremine&nbsp; deficita&nbsp; suša)&nbsp; u&nbsp; odnosu&nbsp; na relativne&nbsp; vrednosti&nbsp; standardizovanih indeksa.&nbsp; Metoda&nbsp; praga&nbsp; je&nbsp; primenjena&nbsp; na39 stanica&nbsp; u&nbsp; slivu&nbsp; Velike&nbsp; Morave&nbsp; za&nbsp; period 1960-2014,&nbsp; što&nbsp; do&nbsp; sad&nbsp; predstavlja&nbsp; najveći uzorak&nbsp; na&nbsp; kojem&nbsp; je&nbsp; primenjivana&nbsp; u&nbsp; Srbiji, bilo&nbsp; da&nbsp; se&nbsp; radi&nbsp; o&nbsp; analizi&nbsp; malih&nbsp; ili elikih&nbsp; voda.&nbsp; Kao&nbsp; prag&nbsp; za&nbsp; izdvajanje&nbsp; suša uzeta&nbsp; je vrednost Q₉₀ ,&nbsp; jer&nbsp; je&nbsp; cilj&nbsp; bio&nbsp; analiza prostornih&nbsp; i vremenskih&nbsp; karakteristika ekstremnih(velikih)&nbsp; suša&nbsp; u&nbsp; slivu&nbsp; Velike Morave.&nbsp; Izbor&nbsp; praga&nbsp; uticao&nbsp; je&nbsp; i&nbsp; na&nbsp; izbor metode&nbsp; parcijalnih&nbsp; serija&nbsp; za&nbsp; statističku analizu karakteristika suša. Za određivanje parametra&nbsp; teorijskih&nbsp; raspodela&nbsp; korišćeni su L-momenti&nbsp; koji&nbsp; daju&nbsp; pouzdanije&nbsp; ocene parametara&nbsp; od&nbsp; običnih&nbsp; momenata.&nbsp; U dosadašnjim&nbsp; radovima,&nbsp; koji&nbsp; su&nbsp; analizirali hidrološke&nbsp; suše&nbsp; metodom&nbsp; parcijalnih serija,&nbsp; funkcija&nbsp; raspodele&nbsp; se&nbsp; unapred odabirala,&nbsp; a&nbsp; ne&nbsp; na&nbsp; osnovu&nbsp; testova saglasnosti&nbsp; i&nbsp; provere&nbsp; grafika&nbsp; verovatnoće,kao&nbsp; što&nbsp; je&nbsp; urađeno&nbsp; u&nbsp; ovoj&nbsp; disertaciji.&nbsp; Za proveru&nbsp; saglasnosti&nbsp; godišnjeg&nbsp; maksimuma deficita&nbsp; i&nbsp; trajanja&nbsp; korišćeni&nbsp; su&nbsp; testovi Kolmogorov-Smirnov&nbsp; i&nbsp; Kramer&ndash;Mizes,&nbsp; na osnovu&nbsp; kojih&nbsp; su&nbsp; izabrane&nbsp; merodavne raspodele&nbsp; za&nbsp; proračun&nbsp; suša&nbsp; različitih povratnih&nbsp; perioda&nbsp; na&nbsp; stanicama,&nbsp; i&nbsp; obrnuto.S&nbsp; pomoću L-moment&nbsp; dijagrama(LC _s/LC_k )utvrđena&nbsp; je&nbsp; homogenost&nbsp; regiona,&nbsp; u&nbsp; ovom slučaju&nbsp; celog&nbsp; sliva&nbsp; Velike&nbsp; Morave,&nbsp; kao&nbsp; i izabrana&nbsp; regionalna&nbsp; raspodela(P+W)&nbsp; za deficite&nbsp; i&nbsp; trajanje&nbsp; suše,&nbsp; na&nbsp; osnovu&nbsp; koje&nbsp; su izračunati&nbsp; bezrazmerni&nbsp; kvantili,&nbsp; koji&nbsp; se mogu&nbsp; koristiti&nbsp; za&nbsp; ocenu&nbsp; suša velikih povratnih&nbsp; perioda&nbsp; na&nbsp; hidrološki neizučenim slivovima.</p> / <p>Hydrological droughts are a complex phenomenon both in terms of the factors that cause it, and in terms of its impact on ecosystems and society. The dissertation shows the advantage of low water analysis, i.e. hydrological drought with two variables (deficit and duration), compared to the usual analysis of a single value (a minimum annual flow). The results obtained by statistical analysis of drought, which are separated by the threshold method clearly demonstrated to have greater applicability in water management than methods that used standardized indices, because they give concrete value of missing quantities of water (drought deficit volume) with respect to relative values of standardized index. Threshold method was&nbsp; applied to 39 stations in the Morava River Basin for the period 1960-2014, which so far represents the largest sample on which it was applied in Serbia, whether it is on the analysis of low or high water. The value of Q₉₀ was selected as a threshold for separating the drought, because the goal was to analyze the spatial and temporal characteristics of extreme (large) droughts in the basin of Velika Morava. Selected threshold affected the choice of partial duration series method for statistical analysis of the drought characteristics. L-moments were used to determine the parameters of&nbsp; theoretical distributions because they give more reliable estimates of the parameters&nbsp; than ordinarymoments. In previous papers, which analyzed the hydrological drought&nbsp; by partial duration series, distribution function was chosen in advance, and not on the results of goodness-of-fit tests and visual validation of frequency curve on probability paper, as it was done in this thesis. To check the goodness-of-fit tests of annual maximum deficit and duration tests of Kolmogorov-Smirnov and Cramer &ndash;Mises were used, and based on their results representative distribution was chosen for&nbsp;&nbsp; calculation of different return periods of droughts on the stations, and vice versa. The homogeneity of the region was determined by L-moment diagrams (LC s/LC k ), and in this case it was the whole basin of the Velika Morava. L-moments were used for selection of regional distribution (P+W) for the drought duration and deficits, based on which dimensionless quantiles were calculated, which can be used for&nbsp;&nbsp; аеssessment of droughts of great return periods in the hydrological ungauged catchments.</p>

The thesis describes a realization of the automatic self tuning system for sevenstring guitars. There are comparisons of commercial and uncommercial solutions for six-string guitars. There is also evaluation of useful parts for seven-string guitars. Thesis contains a description of a requirements for individual parts and a control software with respect on real guitar properties and used computing algorithm. In the second part of thesis, there is a description of final system design and its realisation including the control software. This is also related with testing of the entire system.

The thesis deals with EEG signals, their description, methods of quantitative analysis and the processes in time-frequency domains, or power spectrums. The relationsheep between brain electrical activity and acustic stimuli (Mozart´s “Sonata K448”) was studied using EEG analysis in relation to sound impulses from replayed extracts of. The proposed experiment protocol included recording of EEG of volunteers. In order to visualize and analyze the data, the software with the graphic user interface was created, which enables topological mapping of brain activity and its vizualization in the time-frequency domain.