The human vestibulo-ocular reflex (VOR) stabilizes gaze during head movement. The reflex is typically tested in a clinic or laboratory using passive rotations or artificial stimuli which measure the amount of damage the vestibular apparatus has suffered. However, during everyday activities the vestibular system is stimulated by active, self generated head movements. Head movements are often rapid and associated with the goal of achieving either gaze-fixation or re-fixation. Patients who complain of on-going symptoms will typically identify a particular position or movement that aggravates their symptoms in their everyday life. There is a need to identify objective parameters which correlate with the subjective complaints of patients whose symptoms persist after vestibular damage. In the first study, a gaze-refixation task, patients who complain of ongoing symptoms (poorly-compensated), during rapid head turns, after unilateral vestibular de-afferentation (uVD) were compared with those who did not have the same complaints (well-compensated) and normal subjects. Well- and poorly-compensated groups were sorted according to responses on a standardized questionnaire. All subjects were then located in a real-world, non-laboratory environment in which poorly-compensated subjects reported experiencing symptoms. Each subject’s head, eye and gaze displacement and velocity, head rotation frequency and blink or eye-lid closure were measured and analysed and compared between ipsi- and contra-lesional head rotations within and between subject groups. When subjects are able to generate their own active head rotations it has been suggested that a number of vestibular and extra-vestibular strategies might be employed to compensate for an impaired VOR. In subsequent studies, high resolution scleral search coils were used to identify the compensatory mechanisms used during active head rotations during a gaze-fixation task. A corrective saccade is typically observed during passive ipsilesional head rotations or “impulses” and might be potentiated during rapid, active or self-generated head rotations. The conditions which predict or contribute to the generation of the rapid, corrective eye movement were investigated. The results were compared with responses to passive head impulses of matched velocity and acceleration to determine if active head impulses could be used to identify a lesioned vestibular apparatus as is routinely clinically achieved with passive head impulses.

Ce travail porte sur l'endommagement des matériaux composites stratifiés utilisés notamment pour la réalisation de pièces structurales minces. La dégradation de ces matériaux induite par la création et le développement de surfaces de décohésion internes est abordée sous deux angles. Une campagne expérimentale a tout d'abord été menée sur des stratifiés en carbone-époxy réalisés par infusion de résine liquide et sollicités en traction uniaxiale. Cette étude propose une analyse originale à l'aide de trois techniques optiques permettant une caractérisation de l'endommagement par mesures de champs : cinématiques (par stéréo-corrélation d'images), thermiques (par thermographie infrarouge) et densimétriques (par tomographie à rayons X). Le second volet du travail concerne la modélisation de la microfissuration dans le contexte d'une anisotropie initiale. A cette fin, une homogénéisation bidimensionnelle de milieux orthotropes fissurés permet la prise en compte de défauts d'orientation arbitraire et des effets unilatéraux (ouverture-fermeture des microfissures) au sein d'une formulation énergétique en déformation. Sur cette base, un modèle de comportement est proposé dans le cadre de la thermodynamique des processus irréversibles avec variables internes. Des simulations numériques permettent de démontrer les capacités prédictives de la formulation, en particulier la représentation du comportement non linéaire de ces matériaux, l'interaction entre les anisotropies initiale et induite et la restitution des propriétés élastiques lors de la fermeture de défauts. / This work deals with the damage of laminated composite materials used in particular for the production of thin structural parts. The degradation of these materials induced by the creation and growth of internal microcracks is considered from two angles. An experimental campaign was first conducted on carbon-epoxy laminates made by liquid resin infusion and loaded in uniaxial tension. This study proposes an original analysis using three advanced optical techniques that allow the damage characterization through full-field measurements : kinematic (with stereo-image correlation), thermal (with infrared thermography) and density (with X-ray tomography). The second part of the work concerns the modeling of microcracking in the context of initial anisotropy. To this end, a two-dimensional homogenization of orthotropic cracked media allows consideration of arbitrary orientation of defects and unilateral effects (opening and closing of microcracks) within a strain energetic formulation. On this basis, a constitutive model is proposed in the framework of thermodynamics of irreversible processes with internal variables. Numerical simulations demonstrate the predictive capabilities of the formulation, in particular the representation of the nonlinear behavior of these materials, the interaction between initial and induced anisotropies and the recovery of elastic properties at the closure of microdefects.

Le matériau composite agrégataire énergétique étudié a un comportement viscoélastique endommageable sensible à la pression de confinement et à la température. Ces travaux concernent la modélisation de l'anisotropie induite par endommagement avec deux objectifs principaux. Dans un premier temps, le caractère anisotrope de l'endommagement est mis en évidence expérimentalement. Des essais alternant tension et compression permettant d'observer l'effet unilatéral d'endommagement. Ensuite, un modèle de comportement est développé pour le matériau d'étude. Des modèles pertinents sont tout d'abord comparés. Le modèle le plus approprié est ensuite amélioré par l'ajout de mécanismes d'endommagement, d'effectivité du dommage et d'un mécanisme de plasticité. Les données expérimentales sont utilisées pour identifier les paramètres du modèle. Ce dernier a été ensuite implémenté dans un logiciel de calcul aux éléments finis (Abaqus / standard) sous la forme d'une procédure Fortran (UMAT). Différents types de chargements sont simulés et confrontés aux résultats expérimentaux. / An explosive aggregate material exhibits a visco-elastic behaviour with damage, internal friction and sensitivity to the confining pressure and temperature. This thesis focuses on the anisotropic elastic damage with unilateral effect. The first aim of this study is to highlight experimentally the anisotropic nature of the damage. Then, a new model is proposed for the studied material. This is achieved using a comparison of some relevant models in order to select the most appropriate among them. The selected model is then improved by adding unilateral effect mechanisms and plasticity. Experimental data is used to characterize the material behaviour and to determine the parameters of improved model. This model has been implemented in the finite element software (Abaqus / Standard) using Fortran procedure (UMAT) and then tested for different loads and compared with experimental results.

Maintaining the peace and security by regional arrangements in Africa (focusing on peace-keeping operations) Abstract The present thesis focuses on the issue of peace-keeping operations maintained by the regional and sub-regional organizations in Africa, namely African Union and ECOWAS. The main statement of the thesis is the following: The United Nations is unable to react effectively to threats to international peace and security, especially in cases of mass violations of human rights in intrastate conflicts, that have severe impact on particular region including refugee crisis or spreading the conflict to other states of the region. In the thesis, particular instruments of the above-mentioned international organizations, that create the framework for operations for maintaining peace and security in the region, are described. Attention is also paid to the relevant bodies of the African union and ECOWAS such as Peace and security council of the AU or African standby force. The thesis elaborates on problematic or controversial issues from international law perspective. In the first place, the concept of humanitarian intervention and related concept of responsibility to protect is underlined. It is demonstrated that African Union and ECOWAS have significant contribution to these concepts when implementing...

Le sujet de cette thèse porte sur quelques résultats de convergence pour les inéquations variationnelles avec applications dans l'étude des problèmes aux limites décrivant le contact entre un corps déformable et une fondation. La thèse est composée de deux parties. Dans la première partie, nous nous intéressons à l'analyse des inéquations quasivariationnelles, avec ou sans opérateurs de mémoire, dans un espace de Hilbert. Nous prouvons plusieurs résultats de convergence liés à la perturbation de l'ensemble des contraintes ainsi qu'à une méthode de pénalisation. Aussi, pour une classe d'inéquations quasivariationnelles avec opérateurs de mémoire nous étudions une formulation duale pour laquelle nous présentons des résultats d'existence, d'unicité et d'équivalence. La deuxième partie est consacrée à l'application de ces résultats abstraits dans l'étude de six problèmes de contact pour des matériaux élastiques, viscoélastiques et viscoplastiques, dans le cas statique ou quasistatique. Les lois de contact considérées sont la loi de Signorini, la loi de contact avec compliance normale et contrainte unilatérale et la loi de contact avec contrainte unilatérale et seuil critique. Enfin, nous étudions un nombre de problèmes de contrôle optimal associés aux certains modèles de contact. Pour ces problèmes nous obtenons des résultats d'existence et de convergence. / The topic of this thesis concerns some convergence results for variational inequalities with applications in the study of boundary value problems which describe the contact between a deformable body and a foundation. The thesis is divided into two parts. In the first part, we are interested in the analysis of quasivariational inequalities, with or without history-dependent operators, in Hilbert spaces. We prove some convergence results related to a perturbation of the set of constraints and a penalty method, as well. Moreover, for a class of history-dependent quasivariational inequalities we study a dual formulation for which we present existence, uniqueness and equivalence results. The second part is devoted to applications of these abstract results in the study of six contact problems with elastic, viscoelastic and viscoplastic materials, both in the static or quasistatic case. The contact conditions we consider are the Signorini condition, the normal compliance condition with unilateral constraint, the unilateral constraint condition with yield limit. Finally, we study a number of optimal control problems associated to some contact models. For these problems we provide existence and convergence results.

En matière économique, l'autorisation administrative est un instrument de contrôle du marché dont l'instauration et souvent l'allocation sont théoriquement décidées par l'État. Le recours au marché pour distribuer certaines autorisations administratives bouscule cette présentation. L'autorisation administrative devient l'objet même d'un marché tout en étant un outil censé le réguler. Une fois admise cette ambivalence, se pose la question de la pérennité du contrôle de l'État lorsque l'octroi des autorisations administratives qu'il prévoit repose sur le marché. Susceptible de mettre les bienfaits de ce mode d'allocation des ressources au service de la régulation de l'économie, cette évolution du régime de l'autorisation administrative peut en même temps exprimer la soumission à la loi du marché de la régulation étatique au moyen de l'autorisation administrative.L'objet de cette thèse est de démontrer que l'État n'a qu'une influence limitée sur l'allocation marchande des autorisations administratives à objet économique. Impuissant à empêcher la formation du marché en raison des considérations économiques et psychologiques qui président à sa construction, il l'encourage généralement de façon involontaire ou sous la contrainte. Avec l'Union européenne, les opérateurs économiques soumis à autorisation préalable sont les premiers artisans du marché. Une fois le marché construit, des leviers d'intervention permettent à l'État d'influencer les échanges d'autorisations administratives. En adoptant tour à tour les rôles d'offreur d'autorisations administratives, de demandeur et d'autorité régulatrice, il cumule les facultés de contrôle respectivement attachées à ces fonctions. La circonstance que ces compétences soient toutes partagées et pas nécessairement mises en œuvre atténue notablement ce constat. / In the economic sphere, administrative authorization is traditionally considered a tool used to control the market, with its creation and oftentimes, allocation being, in theory, the result of the State’s decision. Appealing to the market itself for the distribution some administrative authorizations shifts this paradigm. The administrative authorization becomes itself the subject of the market that it supposedly regulates. With this ambivalence having been underlined, the durability of the State’s control over administrative authorizations can be questioned when the market itself determines the authorizations’ distribution. While this evolution could benefit the process of economic regulation with the introduction of its resource distribution model, it could simultaneously reflect the submission of State regulation to the law of the market, through the use of the administrative authorization.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-01-13T12:02:29Z No. of bitstreams: 1 JoseMoisesNunesDaSilva_TESE.pdf: 1427268 bytes, checksum: fd8c54496d732e1dfec80964ad4af651 (MD5) / Approved for entry into archive by Elisangela Moura (lilaalves@gmail.com) on 2016-01-13T12:47:14Z (GMT) No. of bitstreams: 1 JoseMoisesNunesDaSilva_TESE.pdf: 1427268 bytes, checksum: fd8c54496d732e1dfec80964ad4af651 (MD5) / Made available in DSpace on 2016-01-13T12:47:14Z (GMT). No. of bitstreams: 1 JoseMoisesNunesDaSilva_TESE.pdf: 1427268 bytes, checksum: fd8c54496d732e1dfec80964ad4af651 (MD5) Previous issue date: 2014-07-31 / O trabalho trata das concep??es de forma??o profissional t?cnica de n?vel m?dio adotadas peloInstituto Federal de Educa??o, Ci?ncia e Tecnologia do Rio Grande do Norte (IFRN). Discuteessas concep??es a partir dos quatro projetos pol?tico-pedag?gicos constru?dos no per?odo de1970 a 2010, abrangendo tr?s institucionalidades: Escola T?cnica Federal do Rio Grande doNorte (1970-1998), Centro Federal de Educa??o Tecnol?gica do Rio Grande do Norte (1999-2008) e IFRN (a partir de 2008), bem como tr?s contextos pol?ticos importantes do pa?s:Ditadura Civil-Militar, Nova Rep?blica e Per?odo do ide?rio neoliberal no Brasil. O objetivofoi analisar a configura??o das concep??es de forma??o, com ?nfase nas especificidades e(des)continuidades, situando-as no contexto das mudan?as pol?ticas, econ?micas e educacionaisem desenvolvimento no pa?s. Compreende-se como se d? historicamente a rela??o trabalho,educa??o e forma??o humana, a fim de evidenciar como se desenha atualmente a concep??o deforma??o dos trabalhadores, bem como a possibilidade de uma forma??o contra hegem?nica.Analisa-se as caracter?sticas das concep??es formativas de n?vel m?dio esbo?adas nas reformaseducacionais do pa?s. Investiga-se as concep??es de forma??o profissional delineadas nosprojetos pol?tico-pedag?gicos do IFRN, com ?nfase nas especificidades e (des)continuidades.Fez-se uso do materialismo hist?rico-dial?tico, da revis?o bibliogr?fica, da pesquisadocumental e da entrevista realizada com sujeitos que participaram do grupo de trabalhocoordenador da elabora??o dos projetos pol?tico-pedag?gicos institucionais. Os resultadosdemonstram que a forma??o dos trabalhadores na sociedade capitalista tem um car?terunilateral; que a forma??o desejada pela classe trabalhadora ? a forma??o omnilateral; que asconcep??es formativas que permearam as reformas educacionais do pa?s foram todas naperspectiva da forma??o unilateral; que, em determinadas conjunturas, as concep??es deforma??o profissional t?cnica de n?vel m?dio delineadas nos projetos pol?tico-pedag?gicos doIFRN refletem as perspectivas formativas que orientam as reformas educacionais no pa?s(forma??o unilateral) e, em outros momentos, a Institui??o adota concep??es (forma??oomnilateral) que n?o se coadunam com tais perspectivas; que o IFRN procura materializar aconcep??o de forma??o humana integral dos educandos por meio dos cursos t?cnicos integradosao ensino m?dio; e que entre os projetos pol?tico-pedag?gicos constru?dos de 1970 a 2010 h?mais continuidades do que rupturas em rela??o ?s concep??es de forma??o adotadas. Concluiseque, o desafio da IFRN ? institucionalizar em suas a??es educativas a concep??o de forma??oomnilateral assumida nesse documento institucional. / The thesis deals with the concepts of technical tra ining of middle level adopted by the Federal Institute of Education, Science and Technology of R io Grande do Norte (IFRN). Discusses these concepts from the four political-pedagogical projects built in the period 1970 to 2010, spanning three institutionalities: Federal Technica l School of Rio Grande do Norte (1970- 1998), Federal Center of Technological Education of Rio Grande do Norte (1999-2008) and IFRN (from 2008) as well as three important politic al contexts of the country: Civil-Military Dictatorship, New Republic and Period of neoliberal ideas in Brazil. The goal is to analyze the configuration of the conceptions of training adopte d in the political-pedagogical projects IFRN, with emphasis on the specificities and (dis) contin uities, placing them in the context of political, economic and educational change in development in t he country. Addresses the relationship work, education and human development in capitalist society, in order to grasp the concept of employee training engendered by that company as wel l as the possibility of a counter- hegemonic formation. We analyze the formation of mi d-level concepts outlined in the educational reforms implemented in the country. We investigate the concepts of training outlined in the political-pedagogical projects IFRN . Makes use of the historical-dialectical materialism, the literature review, the documentary research and interviews were conducted with subjects who participated in the working group coordinator of the drafting of the political- institutional educational projects. The results sho w that the training of workers in capitalist society has a unilateral character; that the traini ng required by the working class is the omnilateral training; that the formative ideas that permeated the educational reforms in the country between 1970 and 2010 were all envisaged by unilateral training; that, in certain contexts, conceptions of technical training medium level outlined in the political-pedagogical projects IFRN reflect the formative perspectives th at guide educational reforms in the country (unilateral training) and, at other times, the inst itution adopts concepts (training omnilateral) that are not consistent with such prospects; and th at between the political-pedagogical projects built from 1970 to 2010 there are more continuities than breaks in relation to the concepts of training adopted. We conclude that the challenge is to institutionalize the IFRN their educational actions omnilateral designing training undertaken in the political-pedagogical project 2009.

O objetivo é caracterizar a voz e vibração glótica de pregas vocais com paralisia unilateral. Método: trata-se de um estudo retrospectivo que utilizou o banco de dados do grupo de pesquisa em engenharia médica da Universidade Federal de São Carlos. Foram utilizados dados de 35 pacientes adultos (11 homens e 24 mulheres) e cinco instrumentos de análise multidimensional. O primeiro deles foi o protocolo de auto-avaliação (Índice de Desvantagem Vocal - IDV). Foram extraídos os escores de domínio: físico, orgânico, emocional e total. Foram utilizados sinais de voz para realizar as análises: perceptivo-auditiva (escala analógica visual - EVA e parâmetros: grau global - G, rugosidade - R, soprosidade - S, tensão - T e Instabilidade na emissão vocal - I); acústica tradicional (parâmetros de perturbação - Jitter e Shimmer), experimental (parâmetro Coaptação Glótica - CG) e a análise não linear (NL) da dinâmica vocal (parâmetros qualitativos: número de loops, graus de convergência e regularidade; e quantitativos: desvio padrão do eixo e da dispersão - DPE, DPD). A quinta análise utilizou quimografias geradas de videolaringoscopias em alta velocidade para extração de parâmetros quantitativos (Razão de Abertura - RA, de Fechamento - RF e Assimetria). Análise estatística: descritiva e correlação de Spearman. Resultados: A análise perceptiva caracterizou intensidade moderada do desvio vocal. A rugosidade foi o tipo de voz predominante em amostras masculinas (55,84%) e a soprosidade em amostras femininas (63,59%). Os domínios de IDV apresentaram baixo impacto da disfonia na qualidade de vida dos pacientes. Houve correlação do domínio físico com S em amostras masculinas e com todos os parâmetros perceptivos em amostras femininas. Ambas as amostras apresentaram parâmetros de perturbação aumentados (Jitter: 0,90% homens e 1,20% mulheres; Shimmer: 3,30% homens e 2,76% mulheres), e de CG diminuídos (0,28 homens e 0,25 mulheres). Amostras femininas apresentaram correlação de Jitter e Shimmer com os parâmetros perceptivos. Amostras masculinas apresentaram correlação de Jitter com R e de Shimmer com R e T. A CG correlacionou com a S e l em amostras masculinas. Na análise NL da dinâmica vocal de ambas as amostras apresentaram reduzidos: número de loops, grau de convergência e de regularidade, enquanto que os valores de DPE e DPD apresentaram-se aumentados. Houve correlação de parâmetros perceptuais com os da análise NL em ambas as amostras. Os resultados de parâmetros quimográficos são: RA 1,55 para homens e 1,50 para mulheres; RF 0,37 para homens e 0,18 para mulheres; e Assimetria: 23,68º para homens e 9, 85º para mulheres. Todos os parâmetros perceptuais femininos correlacionaram com os quimográficos, exceto a I. A I de amostras masculinas correlacionou com RF. Conclusão: a caracterização vocal de pacientes com paralisia unilateral de pregas vocais foi possível usando a avaliação multidimensional da voz. / The goal is to characterize the voice and glottal vibration of patients with unilateral vocal fold paralysis. Method: this is a retrospective study that used database samples of Universidade de São Carlos\'s research group in medical engineering. Data from 35 adults patients (11 men and 24 women) and five were used. They were used five tools for multidimensional analysis. The first one was the self-assessment protocol (Voice Handicap Index - VHI). Physical, organic, emotional and total scores were extracted. Voice signals were used in analyzes: perceptual (visual analogue scale - VAS and parameters: overall degrees - G, roughness - R, Breathiness - B, tension - T and instability in phonation - I); traditional acoustic (perturbation parameters - Jitter and Shimmer), experimental (glottal cloure parameter - GC) and nonlinear (NL) dynamic vocal analysis (Qualitative: number of loops, regularity and convergence degree. Quantitative: standard deviation of dispersion - SDD and standard deviation of the axis - SDA). The fifth analysis it was performed through extraction of kymographic parameters generated of the High speed videolaryngoscopys (Opening reason - Or; Closed reason - Cr and Asymmetry). Statistical analysis: descriptive and Spearman correlation. Results: perceptual analysis characterized moderate intensity of vocal deviation. Roughness was the predominant kind of voice in males samples (55,84%) and Breathiness in females samples (63,59%). VHI\'s scores showed low impact of dysphonia in the patients\' quality of life. There was correlation between score physical and B in the male samples and between score physical and all perceptual parameters in the female samples. Both samples showed increased of perturbation parameters (Jitter: 0.90% men and 1.20% women and Shimmer: 3.30% men and 2.76% women) and GC decreased (0.28 men and women 0.25). Female samples showed correlation of Jitter and Shimmer with all perceptual parameters. Male samples showed correlation of Jitter with the R and Shimmer with R and T. GC correlation with B and I only male samples. Qualitative NL dynamic vocal analysis showed number of loops, regularity and convergence degree reduced, whereas quantitative analysis of SDD and SDA increased. There were correlations between perceptual parameters and of nonlinear dynamic vocal analysis for both the samples. Results of Kymographic parameters are Or: 1.55 for men and 1.50 for women; Cr: 0.37 for men and 0.18 for women; and Asymmetry: 23.68º for men and 9.85º for women. All perceptual parameters correlate with Or and Cr at female samples, except I. Male samples showed correlation between I and Cr. Conclusion: the vocal characterization of patients with unilateral vocal fold paralysis was possible using the multidimensional voice assessment.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-07-04T17:53:19Z No. of bitstreams: 1 leonardocoelhopertence.pdf: 1941969 bytes, checksum: f7f3753c2825d1dfd1c727018b9807ec (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-13T16:21:57Z (GMT) No. of bitstreams: 1 leonardocoelhopertence.pdf: 1941969 bytes, checksum: f7f3753c2825d1dfd1c727018b9807ec (MD5) / Made available in DSpace on 2016-07-13T16:21:58Z (GMT). No. of bitstreams: 1 leonardocoelhopertence.pdf: 1941969 bytes, checksum: f7f3753c2825d1dfd1c727018b9807ec (MD5) Previous issue date: 2012-06-15 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo do presente estudo foi investigar os efeitos da aplicação contrapesos no VO2, FC e PE durante a pedalada unilateral. Participaram do estudo 11 ciclistas (31 ± 8 anos, 176 ± 8 cm, 70,6 ± 10,8 Kg, 22,7 ± 2,1 Kg.m2, e 64 ± 9 ml.kg-1.min-1). Os ciclistas compareceram ao laboratório em 7 dias diferentes. No primeiro dia, foram submetidos à avaliação antropométrica, a um teste de pedalada bilateral (PB) em carga constante nas potências de 60 e 100 W e cadências de 60, 75 e 90 rpm, seguido por um teste de PB incremental. Do segundo ao sétimo dia, foram realizados os testes de pedalada unilateral (PU) com o membro inferior dominante utilizando os contrapesos de 2,5 kg ou 5,0 kg ou sem contrapeso nas potências de 60 e 100 W. O VO2, FC e PE foram medidos em todos os testes de PB e PU. Os dados foram apresentados por média ± desvio padrão. Foi utilizada ANOVA para medidas repetidas e posteriormente a plotagem de Bland-Altman para verificar a concordância entre a PU e a PB. Na potência de 60 W, a PU pode ser executada sem a necessidade de aplicação de contrapesos. Na potência de 100 W, durante a PU, tanto o contrapeso de 2,5 quanto o de 5,0 Kg equipararam o VO2 com o da PB, independentemente da cadência utilizada. Para a frequência cardíaca e percepção do esforço, o uso de contrapesos na potência de 60 W mostrou-se efetivo em reproduzir a PB. Entretanto, na potência de 100 W, a aplicação de contrapesos tanto para a frequência cardíaca quanto para a percepção do esforço, não foi um método eficaz para tornar a PU similar a PB. / The aim of this study was to investigate the effects of applying counterweight on VO2, HR and RPE during single-leg cycling. The study included 11 cyclists (31 ± 8 years, 176 ± 8 cm, 70.6 ± 10.8 kg, BMI 22.7 ± 2.1 and 64 ± 9ml.kg-1.min-1). The experimental design was divided into 7 different days. On the first day, the volunteers were submitted to anthropometric evaluation, a double-leg test of cadences in powers of 60 and 100 W and cadences of 60, 75 and 90 rpm followed by a double-leg incremental test. From the second to the seventh day, were performed single-leg tests with dominant leg using the counterweight 2.5 kg or 5kg or noncounterweight and in the 60 W and 100 W powers. The VO2, HR and RPE values were measured in all tests. The data were presented by mean ± standard deviation. We used, ANOVA for repeated measures and subsequently the Bland-Altman plot to assess the agreement between single-leg and double-leg cycling. The PU60 was not different from PB60 from the point of view of oxygen uptake. At 100 W workload, both the counterweights 2.5 Kg and 5,0 Kg matched the oxygen uptake, enabling single-leg cycling to be performed with the same metabolic cost of double-leg cycling. However, at 100 W workload, the counterweight apparatus was not effective to make similar single-leg and double-leg cycling based on HR and RPE comparisons.

Les contacts entre une corde vibrante et un obstacle unilatéral interviennent dans de nombreux instruments de musique tels que la tampoura, le sitar ou encore la basse électrique. Ils introduisent une forte non-linéarité dans le mouvement de la corde, qui se traduit notamment par d'importants transferts d'énergie. Dans ce manuscrit, une étude à la fois numérique et expérimentale du contact corde/obstacle est proposée. Trois types de schémas conservatifs sont développés. Ils s'appuient sur une description modale de la corde, ce qui permet un ajustement des fréquences propres et amortissements pour chaque mode. De plus, deux modèles de contact et frottement sont considérés, l'un régularisant et l'autre non. Des comparaisons à la solution analytique dans le cas d'un obstacle ponctuel sont menées et permettent une première validation des modèles. Des protocoles expérimentaux sont ensuite mis en place pour l'étude d'une corde isolée en présence d'un obstacle ponctuel, puis dans le cas d'une corde installée sur une basse électrique, munie ou non de frettes. Une forte concordance des signaux expérimentaux et numériques est observée sur des temps longs, montrant la capacité des modèles à rendre compte des éléments principaux observés expérimentalement. Enfin, une étude paramétrique est conduite dans le cas d'une basse munie de frettes, montrant l'influence de paramètres tels que la position de pincement de la corde et le réglage des frettes sur le son produit. Ces ajustements sont directement liés à des problématiques récurrentes et centrales rencontrées par les musiciens et les luthiers. / Collisions between a vibrating string and a unilateral obstacle arise in a number of instruments such as tanpuras, sitars and electric basses. Contacts introduce a strong nonlinearity in the string motion, resulting in energy transfers. In this document, a numerical and experimental study of string/obstacle contacts is investigated. Three conservative numerical schemes are developed. They rely on a modal description of the string, so that a fine tuning of eigenfrequencies and damping parameters is possible for each mode. Moreover, contact and friction models are numerically treated either with a penalty approach or with a nonsmooth contact dynamics method. In the case of a point obstacle, comparisons to an analytical solution constitute a first validation of models. Experiments are then carried out in the case of an isolated string vibrating against a point obstacle, as well as in the case of a string vibrating against the neck of a fretted or fretless electric bass on which the string is installed. A good agreement is observed between numerical and experimental signals over long durations, showing the ability of models to take into account the essential physical features experimentally observed. Finally, a parametric study is led on a fretted electric bass, showing the influence of parameters such as the plucking position and the fretboard profile on the resulting sound. These adjustements are directly related to common and central issues met by guitar makers and players.