This dissertation examines the stated principle of the supremacy of the public interest over private interest, which is considered in the Brazilian administrative law as one of its pillars, as opposed to the interests of the citizen. The objective is to examine whether this implicit principle really exists in the legal system. Therefore, based on introductory talks-about historical notes about administrative law and state power, and seek the origin and relevance of the principle of the supremacy of the public interest, investigating the indeterminate concept of the public interest as well as the various understandings light on this principle and its influence on the construction of administrative law with current reflections on essentially the period of the welfare state, in pursuit of achievement of full citizenship rights. Then goes on to investigate the situation of the individual, on the rights and guarantees inherent to human dignity. We continue doing an investigation on existing concepts about legal standard, detailing the concept of legal principle and identify proportionality as a measure for weighting of core values and not as a principle. The conclusion reached by pervades counterbalancing and the mitigation principle in favor of the democratic rule of law and protecting citizens. / A presente dissertação versa sobre o dito princípio da supremacia do interesse público sobre o interesse particular, sendo este considerado no direito administrativo brasileiro como um dos seus pilares, quando contrapostos aos interesses do cidadão. Objetiva-se examinar se esse princípio implícito realmente existe no ordenamento jurídico. Para tanto, em sede introdutória, discorre-se sobre notas históricas acerca do direito administrativo e do poder estatal, além de buscar a origem e relevância do princípio da supremacia do interesse público, investigando o conceito indeterminado do interesse público, bem como os diversos entendimentos acerca do comentado princípio e sua influência na construção do direito administrativo atual com reflexos diante essencialmente do período do Estado Social, em busca da conquista de uma cidadania plena de direitos. Em seguida, passa-se a investigar a situação do indivíduo, diante dos direitos e garantias fundamentais, inerente à sua dignidade humana. Prossegue-se fazendo uma averiguação acerca dos conceitos existentes sobre norma jurídica, pormenorizando o conceito de princípio jurídico, além de identificar a proporcionalidade como medida de ponderação de valores fundamentais e não como princípio. A conclusão alcançada perpassa pelo sopesamento e pela mitigação do princípio em prol do Estado Democrático de Direito e da proteção ao cidadão.

Dans ce travail de thèse, on s'intéresse é l'emploi de techniques de traitement de signal de systèmes de communication MIMO (Multiple Input Multiple Output) pour des applications aux réseaux de capteurs sans fil. Les contraintes énergétiques de cette classe de réseau font appel à des topologies particulières et le réseau peut être perçu comme étant un ensemble de grappes de nœuds capteurs. Ceci ouvre la porte à des techniques avancées de communication de type MIMO. Dans un premier temps, les différents aspects caractérisant les réseaux de capteurs sans fil sont introduits. Puis, les efforts engagés pour optimiser la conservation de l'énergie dans ces réseaux sont résumés. Les concepts de base de systèmes MIMOs sont abordés dans le deuxième chapitre et l'exploration par voie numérique de différentes pistes de la technologie MIMO sont exposées. Nous nous intéressons à des techniques de diversité de polarisation dans le cadre de milieux de communication riches en diffuseurs. Par la suite, des méthodes de type beamforming sont proposées pour la localisation dans les réseaux de capteurs sans fil. Le nouvel algorithme de localisation est présenté et les performances sont évaluées. Nous identifions la configuration pour la communication inter-grappes qui permet pour les meilleurs compromis entre énergie et efficacité spectrale dans les réseaux de capteurs sans fil. Finalement, nous envisageons la technique de sélection de nœuds capteurs afin de réduire la consommation de l'énergie dans le réseau de capteur sans fil. / The aim of this work is to study from a signal processing point of view the use of MIMO (Multiple Input Multiple Output) communication systems for algorithms dedicated to wireless sensor networks. We investigate energy-constrained wireless sensor networks and we focus on cluster topology of the network. This topology permits for the use of MIMO communication system model. First, we review different aspects that characterize the wireless sensor network. Then, we introduce the existing strategies for energy conservation in the network. The basic concepts of MIMO systems are presented in the second chapter and numerical results are provided for evaluating the performances of MIMO techniques. Of particular interest, polarization diversity over rich scattering environment is studied. Thereafter, beamforming approach is proposed for the development of an original localization algorithm in wireless sensor network. The novel algorithm is described and performances are evaluated by simulation. We determine the optimal system configuration between a pair of clusters that permits for the highest capacity to energy ratio in the fourth chapter. The final chapter is devoted to sensor nodes selection in wireless sensor network. The aim of using such technique is to make energy conservation in the network.