Esta pesquisa tem por objeto o conflito existente entre o exercício da atividade econômica e a proteção do ambiente, emergindo o questionamento de como conciliar tais valores em busca da melhoria da qualidade de vida das pessoas. Tem-se como objetivo geral analisar a tensão entre a atividade econômica, fundada na livre iniciativa, e o direito ao meio ambiente ecologicamente equilibrado, buscando adotar uma concepção integrada dos artigos 170 e 225 da Constituição Federal brasileira em prol do desenvolvimento sustentável. Para tanto, utilizam-se a análise e a interpretação como instrumentos específicos do saber jurídico, do material existente nas fontes do direito, na literatura especializada e também em acórdãos relevantes do Poder Judiciário, em especial do Supremo Tribunal Federal. A exposição estrutura-se em três capítulos e parte do estudo da ordem econômica para, em seguida, tratar da colisão entre valores constitucionalmente tutelados como a proteção do meio ambiente e a saúde pública versus livre iniciativa e desenvolvimento econômico. Assim, a ponderação de valores é exigida no caso concreto, cabendo ao Poder Judiciário resolver conflitos de interesses trazidos a sua apreciação. Após, o exame recai sobre a política ambiental o que permitiu identificar os instrumentos de compatibilização do desenvolvimento econômicosocial com a preservação ambiental, destacando-se de modo especial o estudo de impacto ambiental e o relatório de impacto sobre o meio ambiente (EIA/RIMA), bem como o procedimento administrativo de licenciamento ambiental. A partir da análise conjunta das normas da ordem econômica e do meio ambiente, pôde-se verificar que ambos os ramos são amparados pela mesma base principiológica e estão ligados pelos mesmos objetivos, uma vez que se preocupam com a qualidade de vida e bem-estar das pessoas, buscando assegurar a todos uma existência digna e a realização da justiça social. Constatou-se, como principal resultado, que os direitos fundamentais, previstos respectivamente nos artigos 170 e 225 da Constituição Federal, evidenciam a garantia do princípio da dignidade humana, motivo pelo qual a livre iniciativa e o direito ao meio ambiente devem coexistir. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this research is the existing conflict between the exercise of economic activity and environment protection, emerging from the questioning of how to reconcile such values in the search for an improvement in people’s lives. The general objective is to analyse the tension between economic activity, grounded in free initiative, and the right for an ecologically balanced environment, aiming at adopting an integrated conception of articles 170 and 225 of the Brazilian Federal Constitution towards sustainable development. Thus, analysis and interpretation are used as specific tools for juridical knowledge, of pertinent material in the sources of law, in specialized literature and also in relevant judgments by the judiciary, especially in the Supreme Federal Court. The exposition and section of the study of economical order are structured in three chapters, followed by the collision between values constitutionally safeguarded, such as environment protection and public health versus free initiative and economic development. Thus, consideration of the values is demanded in concrete cases, with the Judicial Power responsible for settling conflicts and interests brought about. Afterwards, the test falls on environment policies, which allows for identifying compatibilization tools of social-economic development with environment preservation, highlighting the study of environmental impact and the impact report on the environment (EIA/RIMA), as well as administrative procedures of environmental licenses. From the combined analysis of economic rules and the environment, it was possible to observe that both segments are supported by the same principal basis and are linked to the same objectives, since they are concerned with the quality of life and well-being of the individual, aimed at assuring all of a worthy life and social justice fulfilment. It could be observed that, as a main result, the fundamental rights, provided in articles 170 and 225 of the Federal Constitution, evidence the guarantee of the principals of human dignity, reason which free initiative and the right for the environment should co-exist.

O objeto da discussão é a racionalidade das decisões judiciais em casos em que se constata conflito de princípios ou entre princípios e regras, casos esses considerados difíceis, uma vez que não há no ordenamento jurídico solução predeterminada que permita mera subsunção dos fatos à norma. São examinados métodos alternativos ao de subsunção. O primeiro é o método da ponderação, difundido principalmente por Robert Alexy, com suas variantes. Entretanto, o problema que surge com a aplicação do método da ponderação é da imponderabilidade entre ponderação e vinculação à lei, ou seja, a escolha dos pesos dos princípios e sua potencial desvinculação da lei. O segundo modelo, chamado de coerentista, busca conferir alguma racionalidade e fornecer critérios que poderiam explicar escolhas entre valores conflitantes subjacentes à legislação e mesmo aos pesos do método de ponderação. Dentro do modelo coerentista, examina-se em particular a versão inferencial que explora a coerência entre regras e princípios pela inferência abdutiva dos princípios a partir das regras. A aplicação dos diferentes modelos é feita em duas decisões prolatadas pelo Supremo Tribunal Federal em casos de conflito de princípio, casos Ellwanger e de aborto de anencéfalos. O que não permite generalização, mas oferece ilustrações específicas das virtudes e vícios desses modelos de decisão. / The subject of this study is rationality of judgments when there is collision of principles or conflict between principles and rules, which are hard cases, since there is no predetermined solution in legal system that allows only subsuming facts to the norm. Alternative methods are then examined. The first is the method of weighting and balancing proposed mainly by Robert Alexy, in spite of its variants. However, the difficulty to apply such method is theweightlessness between weighing and law binding, that is, the choice of weight of principles and its untying to the Law. The second model, called coherence model, intends to reach any rationality and provide criteria that could explain choices between conflicting values underlying Law and also the ascription of weights of the weighing and balancing method. In coherence model, it is studied especially its inferential version that explores coherence between rules and principles through abduction of principles from rules. These methods are tested in two decisions by Brazilian Supreme Court in cases of collision of principle, in Ellwanger and anencephalic abortion cases. That does not allow a general approach, but only specific outlines of the virtues and defects of these models of decision.

O objetivo de investigar colisões de íons pesados no regime relativístico é de estudar os quarks e glúons em condições extremas de pressão, densidade e temperatura, reproduzindo as condições da matéria nos instantes iniciais da formação do universo. Nesse trabalho, a energia transversal ET foi investigada para colisões Au+Au no experimento STAR no RHIC a energias de feixe no intervalo de 7.7 à 200 GeV. A dependência do ET normalizado pelo número de participantes em função da centralidade e energia de colisão foi medida, bem como a dependência do ET dividido pela densidade de partículas carregadas em função da energia de colisão para colisões centrais. Os resultados desse estudo indicam que para energias menores do que 7.7 GeV, a energia transversal média por unidade de carga produzida varia significativamente com o aumento da energia de colisão, atingindo o limite de saturação para o intervalo de energias maiores do que 7.7 GeV, onde essa razão passa a ser praticamente constante em função da energia de colisão. Por fim, a componente eletromagnética da energia transversal também foi medida, e os resultados indicam que para as energias mais baixas o estado final é dominado por bárions, ao passo que para altas energias o mesmo é dominado por mésons. / The goal of relativistic heavy-ion collisions is to study the behavior of quarks and gluons under extreme conditions of pressure, density and temperature, such as those expected to have existed in the the beginning of the universe. In this work, the transverse energy ET was investigated for Au+Au collisions measured with the STAR experiment at RHIC with beam energies from 7.7 to 200 GeV. The centrality and collision energy dependence of ET per number of participants was measured, as well as the energy dependence for the ET per charged particles in central collisions. The results indicate that for collision energies less than 7.7 GeV the average transverse energy per unit charge varies significantly with increasing collision energy, reaching the saturation limit for energies higher than 7.7 GeV, where this ratio becomes almost constant. The electromagnetic fraction of the total ET was estimated, and the results are in agreement with a final state dominated by baryons, for lower energies, and a meson dominated state for higher energies.

Orientador: Antonio Celso Fonseca de Arruda / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-07-25T02:09:03Z (GMT). No. of bitstreams: 1 Occhipinti_Sidney_M.pdf: 8988528 bytes, checksum: e17897bc9750a7e5e1ed1f1db7521660 (MD5) Previous issue date: 1999 / Resumo: Geralmente ao ocorrer acidente entre automóvel e a traseira de caminhão,os danos são bem severos para os ocupantes do automóvel e na maioria dos casos, este só pára ao atingir o eixo do caminhão. Isto ocorre, porque os pára-choques de caminhões são mal posicionados, frágeis, fixados excessivamente altos e muito embutidos na carroçaria. Ocorrem neste caso, dois efeitos: o cunha (em que o automóvel penetra sob a traseira do caminhão impulsionando-o para cima); e o guilhotina (a carroçaria do caminhão destrói o pára-brisa, as colunas do teto e decapta os ocupantes). Pára-choque traseiro de caminhão é equipamento de segurança veicular passiva, para parar o veículo que se choca contra ele, na realidade porém, diverge deste pressuposto teórico. Infelizmentetanto no Brasil, como em outros países, eles não apresentam performance satisfatória. Preocupado com o problema, o Engº Luis O. F. Schmutzler idealizou o pára-choque alicate equipado com rede de cabos de aço para absorção de energia. Este trabalho enfoca a análise e o estudo das solicitações mecânicas abordando os esforços envolvidos no impacto; projeto do párachoque; construção, instalação, execução de teste de impacto e análise dos resultados. O teste foi realizado na velocidade de 64 km/h, chocando 50% da região dianteira do carro, com resultados excelentes: baixo risco de lesão corporal e preservação total da integridade da cabina do auto / Abstract: Generally a collision of a car with the rear end of a truck results in serious injuries to the car occupants. Underride occurs because the barriers of trucks present some problems.: They are relatively high, their installation are toa inside off rear end of the truck structure, and they are ftagile. AlI these conditions allow the car underride to be stopped at the rear axle and tires. Two failing effects occurs: the wedge (the car go through the rear end pulling up the truck); and the guillotine (the rear end of the truck shear the ftont car columns, destroying windshield, roof and unfortunately decapitating car's occupants). Truck rear underride guard is a passive vehicular security equipment design to stop ungovemed cars. Unfortunately actual rear truck barriers in Brazil and others countries do not provide a satisfactory performance. Conceptual pliers underride guard equipped with a steel cable net was proposed by engineer LUIS O. F. SCHMUTZLER to absorb great part ofthe impact energy. This is the analysis, ofthe mechanical efforts and study in case of a rear collision with: impact efforts consideration; a steel cable net energy absorber design; barrier construction, installation, crash test and results analysis.The crash test was accomplished at 64km/h and 50% offset at the driver side's car with excellent results, presenting low injuries risks to the car's passengers and the cab integrity was totally preserved. / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

La plupart des simulations interactives ont besoin d'un modèle de détection de collisions. Cette détection nécessite d'une part d'effectuer des requêtes de proximité entre les entités concernées et d'autre part de calculer un comportement à appliquer. Afin d'effectuer ces requêtes, les entités présentes dans une scène sont soit hiérarchisées dans un arbre ou dans un graphe de proximité, soit plongées dans une grille d'enregistrement. Nous présentons un nouveau modèle de détection de collisions s'appuyant sur deux piliers : une représentation de l'environnement par des cartes combinatoires multirésolutions et un suivi en temps réel de particules plongées dans ces cartes. Ce modèle nous permet de représenter des environnements complexes tout en suivant en temps réel les entités évoluant dans cet environnement. Nous présentons des outils d'enregistrement et de maintien de l'enregistrement de particules, d'arêtes et de surfaces dans des cartes combinatoires volumiques multirésolutions. / Most interactive simulations need a collision detection system. First, this system requires the querying of the proximity between the objects and then the computing of the behaviour to be applied. In order to perform these queries, the objects present in a scene are either classified in a tree, in a proximity graph, or embedded inside a registration grid.Our work present a new collision detection model based on two main concepts: representing the environment with a combinatorial multiresolution map, and tracking in real-time particles embedded inside this map. This model allows us to simulate complex environments while following in real-time the entities that are evolving within it.We present our framework used to register and update the registration of particles, edges and surfaces in volumetric combinatorial multiresolution maps. Results have been validated first in 2D with a crowd simulation application and then in 3D, in the medical field, with a percutaneous surgery simulation.

Injuries related to snowmobiles, motorcycles and moose-car collisions have increased. The aim of the present thesis was to analyse mechanisms and consequences in fatal and non-fatal accidents of these types, and to penetrate possible preventive measures. Snowmobiles The median age of the injured was 30 and of the killed 32, males pre­dominating. A majority of the accidents occurred during weekends, and especially the fatal accidents occurred after dark. The extremities were the most commonly injured parts of the body, however, drowning, crushed chest and cranial injuries caused most of the fatalities. Among the fatalities, four out of five were under the influence of alcohol. The present Swedish laws regarding snowmobiles seem well motivated. "Built-in" safety measures in the construction of the snowmobiles, pro­perly designed snowmobile tracks and functional search and rescue sys­tems could reduce the injuries. Motorcycles The median age was 19 years for both the traffic injured and the kil­led. Half of the traffic accidents were collisions with other motor ve­hicles. In the fatally injured group, also collisions with fixed road­side objects were common. Of the fatally injured, more than every fifth person died in an accident where alcohol was an influential factor. In the injured group, lower extremity injuries (especially in off-road riding) were common and among the fatalities most riders died from injuries to the head or chest. Out of one thousand motorcycle riders interviewed, 45% reported wobbling experiences (8% reported severe wobbling). Possible injury reducing measures include increasing the licensing age, more discriminating driving test, "built-in" restriction of the motorcycle's top speed, elimination of motorcycles prone to wobbling, and a more intensive traffic supervision (speeding, alco­hol). Moose-car collisitions The median age of the drivers was 38 years. Most collisions happened at dusk or when dark (3/4). The median collision speed was 70 km/h. The damage to the car was typical, the roof and the windshield pillars were deformed downwards and backwards. The broken windshield was often pressed into the passenger compartment. Most of the injured car occu­pants suffered cuts predominantly to the head and upper extremities. Nearly all the fatally injured died of head and neck injuries. The injuries may be reduced by strengthening the roof and the windshield pillars, and by introducing anti 1 acerati ve windshields. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1985</p> / digitalisering@umu

Dû au grand intérêt porté à la simulation de foules, beaucoup d'algorithmes ont été et sont encore proposés. Toutefois, (1) il n'existe pas de méthode standard pour évaluer le réalisme et la flexibilité de ces algorithmes, et (2) même les algorithmes les plus récents produisent encore des artéfacts évidents. Abordant la première question, nous proposons une méthode visant à évaluer le réalisme des algorithmes de simulation de foules d'une manière objective et impartiale. ''Objective'' grâce à des métriques quantifiant la similitude entre les simulations et des données acquises en situation réelle. ''Impartiale'' grâce à l'estimation de paramètres permettant d'étalonner automatiquement les algorithmes en vue de décrire au mieux les données (par rapport aux métriques), permettant de comparer les algorithmes au mieux de leur capacité. Nous explorons aussi comment ce processus permet d'augmenter le niveau de contrôle d'un utilisateur sur la simulation tout en réduisant son implication. Abordant la deuxième question, nous proposons un nouvel algorithme d'évitement de collisions. Alors que les algorithmes existants prédisent les collisions en extrapolant linéairement les trajectoires des agents, nous allons au-delà grâce à une approche probabiliste et non-linéaire, prenant en compte entre autres la configuration de l'environnement, les trajectoires passées et les interactions avec les obstacles. Nous éliminons ainsi des simulations résultantes des artefacts tels que : les ralentissements et les agglomérats dérangeants d'agents, les mouvements oscillatoires non naturels, ou encore les manœuvres d'évitement exagérées/fausses/de dernière minute. Dans une troisième contribution, nous abordons aussi l'utilisation de notre travail sur l'évaluation et l'estimation de paramètres dans le cadre de systèmes plus larges. Dans un premier temps, nous l'appliquons à la simulation d'insectes, prenant en charge leur comportement local. Après avoir complété le système aux niveaux intermédiaire et global, cette approche basée-données est capable de simuler correctement des essaims d'insectes. Dans un second temps, nous appliquons notre travail au suivi de piétons, construisant un ''méta-algorithme'' servant à calculer la probabilité de transition d'un filtre particulaire, et surpassant les systèmes existants. / With the considerable attention crowd simulation has received, many algorithms have been and are being proposed. Yet, (1) there exists no standard scheme to evaluate the accuracy and flexibility of these algorithms, and (2) even the most recent algorithms produce noticeable simulation artifacts. Addressing the first issue, we propose a framework aiming to provide an objective and fair evaluation of the realism of crowd simulation algorithms. ''Objective'' here means the use of various metrics quantifying the similarity between simulations and ground-truth data acquired with real pedestrians. ''Fair'' here means the use of parameter estimation to automatically tune the tested algorithms to match the ground-truth data as closely as possible (with respect to the metrics), effectively allowing to compare algorithms at the best of their capability. We also explore how this process can increase a user's control on the simulation while reducing the amount of necessary intervention. Addressing the second issue, we propose a new collision-avoidance algorithm. Where current algorithms predict collisions by linearly extrapolating agents' trajectories, we better predict agents' future motions in a probabilistic, non-linear way, taking into account environment layout, agent's past trajectories and interactions with other obstacles among other cues. Resulting simulations do away with common artifacts such as: slowdowns and visually erroneous agent agglutinations, unnatural oscillation motions, or exaggerated/last-minute/false-positive avoidance manoeuvres. In a third contribution, we also explore how evaluation and parameter estimation can be used as part of wider systems. First, we apply it to insect simulation, taking care of local insect behavior. After completing it at the intermediate and global levels, the resulting data-driven system is able to correctly simulate insect swarms. Second, we apply our work to pedestrian tracking, constructing a ''meta-algorithm'', more accurately computing motion priors for a particle-filter-based tracker, outperforming existing systems.

L'hydrogène moléculaire est la molécule la plus abondante dans l'Univers. Il est reconnu que cette molécule ne peut se former que par un processus catalytique. Les études théoriques ont été menées très récemment sur la forstérite [010] cristalline et amorphe. C'est dans ce cadre que se situe notre étude qui porte sur les réactions de formation de l'hydrogène moléculaire sur des modèles de surfaces silicées et silicatées.Dans un premier temps, nous avons étudié la réaction d'abstraction par l'hydrogène atomique à partir du tétramethylsilane en phase gazeuse. La CVT incluant la correction SCT a été appliquée pour étudier la cinétique des réactions dans un intervalle de températures allant de 180 K à 2000 K. Etant donnée l'importance de l'effet tunnel à basse température, nous avons entrepris des calculs de dynamique quantique. Pour ce faire, une surface d'énergie potentielle en coordonnées hyper-sphériques a été construite. Le calcul quantique a été réalisé en utilisant une approche à dimensionnalité réduite à deux dimensions appliquée à ce problème de collision réactive colinéaire. Les résultats montrent que H2 est principalement formé dans son état vibrationnel fondamental. La comparaison avec les résultats expérimentaux réalisés dans le domaine de températures 425-570 K montre un accord satisfaisant. Une étude de formation de H2 sur des nanosilicates a été menée. Les méthodes de la DFT ont permis d'identifier les sites de physisorption et de chimisorption d'atomes d'hydrogène, d'étudier la diffusion de l'atome H physisorbé sur le cluster, de déterminer les caractéristiques énergétiques de ces sites et les énergies d'activation pour la désorption et la recombinaison de H2. / Molecular hydrogen is the most abundant molecule in the Universe. It was recognized long ago that the formation of molecular hydrogen most likely occurs on dust grains. Theoretical studies have focused on H2 formation mainly on model graphite surfaces and very recently on polycrystalline and amorphous foresterite [010]. It is within this framework that lies our study addressing the molecular hydrogen formation on new models of siliceous and silicateous surfaces. First, we studied the abstraction reaction by atomic hydrogen from tetramethylsilane in the gas phase. We used accurate methods of quantum chemistry based on the second-order perturbation theory and on the coupled clusters method. The KIEs and SKIEs were highlighted. CVT/SCT correction was applied to compute the reaction kinetics for a wide temperature range (180-2000 K). Given the importance of the quantum tunnelling effects at low temperatures, we investigated state-selected dynamics using quantum dynamics calculations. In order to achieve this purpose, a two-dimensional potential energy surface in the hyperspherical coordinates representation was built. Quantum calculations were performed using a reduced dimensionality approach applied to this collinear reactive collision problem. The comparison with the experimental results, performed within a temperature range between 425 and 570 K, shows a reasonable agreement.The H2 formation on nanosilicates, prototypes of silicate surfaces, was investigated. Using DFT, we identified physisorption and chemisorption sites for hydrogen atoms, then studied the diffusion of physisorbed hydrogen on the nanoclusters and calculated the energy properties and the activation energies for H2 recombination and desorption into the gas phase. Amorphous/porous grains with forsteritic composition tend to dissociate H2 and that the more crystalline/compact silicate grains would tend to catalyse H2 formation.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2015-12-16T17:29:20Z No. of bitstreams: 1 alexandremenezesteixeira.pdf: 8409444 bytes, checksum: df76f8cbe4e829db629062da1fd25bc7 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2015-12-17T11:07:03Z (GMT) No. of bitstreams: 1 alexandremenezesteixeira.pdf: 8409444 bytes, checksum: df76f8cbe4e829db629062da1fd25bc7 (MD5) / Made available in DSpace on 2015-12-17T11:07:03Z (GMT). No. of bitstreams: 1 alexandremenezesteixeira.pdf: 8409444 bytes, checksum: df76f8cbe4e829db629062da1fd25bc7 (MD5) Previous issue date: 2015-02-23 / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / Monitorar um ambiente através de múltiplos robôs autônomos em um espaço compartilhado sem que haja colisões é um grande desafio nos dias atuais. Várias pesquisas na área de robótica tem sido feitas para desenvolver essa tarefa. Sendo assim, este trabalho atua na coordenação de movimento de múltiplos robôs de serviço percorrendo de forma cíclica caminhos que se interceptam. É desejável que os robôs sigam pelos caminhos inicialmente planejados sem mudá-los durante a missão. Para evitar possíveis colisões, um controlador central foi desenvolvido para planejar as velocidades médias que os robôs deverão efetuar em cada trecho do circuito, maximizando o menor intervalo de tempo t que eles cruzam por um mesmo ponto de colisão. A solução centralizada utilizada neste trabalho foi modelada como um problema Mixed Interger Linear Programming (MILP) sendo usado o software Linear Interactive and General Optimizer (LINGO) para maximizar t e encontrar para cada robô os tempos de percurso para cada parte do caminho. Foi desenvolvida uma aplicação em C++ capaz de iniciar o processo de otimização e receber os tempos otimizados de percurso de cada robô, usados para determinar as suas respectivas velocidades médias. Além disso, esta rotina de programação teve como objetivo realizar o controle dos robôs, navegando-os com o auxílio do framework Robot Operating System (ROS) integrado ao LINGO. Para localizá-los no espaço utilizou-se um pacote de visão computacional do ROS denominado ARPOSE, com o intuito de descobrir suas respectivas posições e orientações em relação à um eixo de referência global. Por fim, simulações e testes reais foram realizados sobre um grupo de robôs para demonstrar a eficácia da abordagem. Os resultados obtidos foram satisfatórios, o que possibilitou atingir os objetivos propostos. / Monitoring an environment using multi-autonomous robots operating in a shared workspace without collisions with each other is a great challenge nowadays. Many researchs have been done to develop this important task in robotics. Thus, this thesis deals with coordinating the motions of multiple working robots traversing periodic intersecting paths. It is desired that mobile robots following the initially designed paths without change them during the mission. To avoid any collision a centralized controller was developed to planner the velocity profile of the robots over the predefined paths, maximizing the smallest time margin t that the robots cross over a same collision point. The centralized solution used in this work was modeled as a Mixed Integer Linear Programming (MILP) problem using the Linear Interactive and General Optimizer (LINGO) software to maximize t and to find for each robot the sub-path traversal time. It was developed a C++ code capable to start the optimization process and receive for each robot the optimized traversal times, used to calculate their respectives average speeds. Besides, this code was used to control the robots, which was done through the Robot Operating System (ROS) framework integrated with LINGO. A computer vision ROS package named ARPOSE was used to localize the robots during the task, calculating their poses relative the global reference frame. Finally, to demonstrate the effectiveness of the approach, simulantions and real tests was performed on mobile robots group. The results obtained were satisfactory, which allowed to achieve the goals.

Nous étudions des fluctuations qui sont omniprésentes dans des collisions entre particules aux hautes énergies. Ces fluctuations peuvent être de nature classique ou quantique et nous allons considérer ces deux cas. D'abord, nous étudions les fluctuations quantiques qui sont présentes dans des collisions entre protons. Celles-ci sont calculables en théorie quantique des champs, et nous allons nous concentrer sur une certaine classe de diagrammes dans ce cadre. Dans un second temps nous allons étudier des fluctuations qui sont présentes dans des collisions entre particules plus lourdes que le proton. Celles-ci sont décrites par les lois quantiques de la nature qui donnent les positions des nucléons dans le noyau, ou bien des fluctuations classiques, d'origine thermique, qui affectent l'évolution hydrodynamique du milieu produit dans une collision. Les fluctuations dans des collisions entre protons peuvent être calculées analytiquement jusqu'à un certain ordre en théorie quantique des champs. Nous allons nous concentrer sur des diagrammes à une boucle, d'une topologie donnée. Ces diagrammes aux boucles donnent des intégrales, qui typiquement sont difficiles à calculer. Nous allons démontrer comment des outils des mathématiques modernes peuvent être utilisés pour faciliter leur évaluation. En particulier, nous allons étudier des relations entre des coupures d'un diagramme, la discontinuité à travers d'un branchement et le coproduit. Nous allons démontrer comment l'intégrale originale peut être reconstruit à partir de l'information contenue dans le coproduit. Nous nous attendons à ce que ces méthodes seront utiles pour le calcul des diagrammes avec des topologies plus difficiles et ainsi aident au calcul des nouvelles amplitudes de diffusion. A la fin, nous étudions les deux types de fluctuations qui ont lieu dans des collisions entre ions lourds. Celles-ci sont liées soit à l'état initial de la matière, soit à l'état intermédiaire produit dans une telle collision. Les fluctuations de l'état initial ont été mesurées expérimentalement, et on voit qu'elles donnent lieu à des non-Gaussianités dans le spectre final de particules. Nous allons démontrer comment ces non-Gaussianités peuvent être comprises comme des positions et des énergies d'interaction aléatoires des 'sources' dans les noyaux entrant en collision. En plus, nous étudions le bruit hydrodynamique dans le milieu produit juste après une collision. Le comportement de ce milieu est celui d'un fluide à basse viscosité. / We study fluctuations that are omnipresent in high-energy particle collisions. These fluctuations can be either of either classical or quantum origin and we will study both. Firstly, we consider the type of quantum fluctuations that arise in proton-proton collisions. These are computable perturbatively in quantum field theory and we will focus on a specific class of diagrams in this set-up. Secondly, we will consider the fluctuations that are present in collisions between nuclei that can be heavier than protons. These are the quantum laws of nature that describe the positions of nucleons within a nucleus, but also the hydrodynamic fluctuations of classical, thermal origin that affect the evolution of the medium produced in heavy-ion collisions. The fluctuations arising in proton-proton collisions can be computed analytically up to a certain order in perturbative quantum field theory. We will focus on one-loop diagrams of a fixed topology. Loop diagrams give rise to integrals that typically are hard to evaluate. We show how modern mathematical methods can be used to ease their computation. We will study the relations among unitarity cuts of a diagram, the discontinuity across the corresponding branch cut and the coproduct. We show how the original integral corresponding to a given diagram can be reconstructed from the information contained in the coproduct. We expect that these methods can be applied to solve more complicated topologies and help in the computation of new amplitudes in the future. Finally, we study the two types of fluctuations arising in heavy-ion collisions. These are related either to the initial state or the intermediate state of matter produced in such collisions. The initial state fluctuations are experimentally observed to give rise to non-Gaussianities in the final-state spectra. We show how these non-Gaussianities can be explained by the random position and interaction energy of `sources' in the colliding nuclei. Furthermore, we investigate the effect of hydrodynamical noise in the evolution of the medium produced just after a collision. This medium behaves like a fluid with a very low viscosity, and so the corresponding evolution is hydrodynamical.