In dieser Arbeit wird das Verhalten der Fahrer vor, während und nach dem Spurwechsel anhand eines Datensatzes untersucht. Dieser wurde im Jahr 2006 in den USA erhoben und enthält die genauen Trajektoriendaten für jedes Fahrzeug. Es konnte gezeigt werden, dass schnellere Fahrzeuge ihren Spurwechsel auch schneller abschließen. Es ist auch erkennbar, dass bei einem Wechsel nach rechts kein kleinerer Abstand zum Vorderfahrzeug in Kauf genommen wird. Eine Untersuchung der freiwilligen und notwendigen Wechsel konnte keine signifikanten Unterschiede feststellen. Im zweiten Teil der Auswertung wurden die Spurwechselentscheidungen mittels eines generellen Modells und MOBIL untersucht. Die einzusetzenden Werte wurden mit den Fahrzeugfolgemodellen OVM, Gipps-Modell und IDM erzeugt. Die Entscheidungen der Spurwechselmodelle fielen nur selten so aus, wie sie in der Realität getroffen wurden. Damit werden die Modelle ihrem eigenen Anspruch nicht gerecht, die Realität möglichst gut nachzubilden. / The topic of this master thesis is the investigation of the behaviour of the drivers before, during and after lane changes on highways. For this purpose a data set of the I-80 in the USA was used. It was collected in 2006 and contains the trajectories of all vehicles. It could be shown that faster cars even do a faster lane change. The drivers also do not accept a smaller gap to the preceding car after a lane change to the right. A comparison of voluntary and necessary lane changes did not show significant differences. In the second part of the analysis the lane change decision was examined using a general model and MOBIL. The data to be inserted were generated using the car-following models OVM, Gipps-model and IDM. But the outcomes of the lane change models only rarely matched reality. Therefore, the models did not fulfill their own standards to picture the existing reality.

No description available.

Measurements of the differential cross sections for backward (pi)('+)p and (pi)('-)p elastic scattering have been made for incident pion momenta between 30 and 90 GeV/c in the angular range 0 ) p(pi)('-), the (DELTA)(,(delta)) and N(,(alpha)) for (pi)('+)p (--->) p(pi)('+). As is given by this model, the momentum dependence of the differential cross-section, d(sigma)/du for fixed u, may be parameterized with the form (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI) The values n('+) = 2.31 (+OR-) 0.07 and n('-) = 2.08 (+OR-) 0.06 are obtained for n at u = 0 for (pi)('+) and (pi)('-) scattering respectively.

Fractional calculus enables the possibility of using real number powers or complex number powers of the differentiation operator. The fundamental connection between fractional calculus and subordination processes is explored and affords a physical interpretation for a fractional trajectory, that being an average over an ensemble of stochastic trajectories. With an ensemble average perspective, the explanation of the behavior of fractional chaotic systems changes dramatically. Before now what has been interpreted as intrinsic friction is actually a form of non-Markovian dissipation that automatically arises from adopting the fractional calculus, is shown to be a manifestation of decorrelations between trajectories. Nonlinear Langevin equation describes the mean field of a finite size complex network at criticality. Critical phenomena and temporal complexity are two very important issues of modern nonlinear dynamics and the link between them found by the author can significantly improve the understanding behavior of dynamical systems at criticality. The subject of temporal complexity addresses the challenging and especially helpful in addressing fundamental physical science issues beyond the limits of reductionism.

Les exploitations de polyculture-élevage sont de plus en plus reconnues au plan international comme limitant les problèmes environnementaux tout en permettant une agriculture productive et économiquement viable. Les incitations à la spécialisation de la PAC et la diminution de la main d'oeuvre agricole les ont néanmoins marginalisées en Europe. Cette thèse vise à éclairer les conditions de maintien d'exploitations de polyculture-élevage durables. Un travail en partenariat avec des agriculteurs, maires et conseillers agricoles a été conduit sur un cas d'étude en zone défavorisée simple française, les Coteaux de Gascogne. Nos travaux ont montré que, malgré une forte variabilité entre exploitations, la polyculture-élevage locale était un bon compromis par rapport à la spécialisation pour une durabilité environnementale et économique. Une analyse des trajectoires passées des exploitations nous a permis d'éclairer quatre types de « chemins pour durer » en polyculture-élevage. Parmi ceux-ci, deux sont apparus pertinents pour le maintien de la polyculture-élevage en contexte incertain : « maximiser l'autonomie » et « diversifier les ateliers ». Sur la base de ces deux types de trajectoires, nous avons co-construit avec les partenaires deux scénarios techniques prospectifs. Pour le type « maximiser l'autonomie », implanter des intercultures fourragères basées sur des légumineuses permettrait de favoriser l'autonomie alimentaire du troupeau en maintenant la fertilité des sols. Pour le type « diversifier les ateliers », finir des génisses permettrait de les valoriser en circuit court. Ces scénarios ont été adaptés puis simulés sur des exploitations locales. Ce type de démarche a permis i) d'impliquer fortement les acteurs locaux via des réunions collectives et ii) une approche prospective originale fondée sur une étude rétrospective intégrant le temps long. / Mixed crop-livestock farms are again attracting worldwide interest, as they are considered to be a good way to limit environmental problems while allowing a productive and economically viable agriculture. The incentives of the Common Agricultural Policy and decreasing workforce availability nevertheless marginalized these farms in Europe. This thesis aims at understanding the conditions for a survival of sustainable mixed crop-livestock farms. A partnership process with farmers, mayors and technical advisers has been led in a French less favoured area, the Coteaux de Gascogne. Our work has shown that even if a wide variability existed between farms, local mixed crop-livestock farming was a good trade-off compared to farm specialization concerning an environmental and economic sustainability. An analysis of farm past trajectories allowed us to enlighten four “paths to last” in mixed crop-livestock farming. Two of these ones appeared to be suitable paths to maintain mixed crop-livestock farms in a uncertain context: “maximizing autonomy” and “diversification of production units”. On the basis of these two types of trajectories, we have co-constructed with local actors two technical prospective scenarios. In line with the type “maximizing autonomy”, forage legume intercropping could enable to autonomously feed the bovine herd while maintaining soil fertility. In line with the type “diversification of production units”, fattening heifers would allow a commercialization through short circuit. These scenarios have been adapted and then simulated on local farms. This type of approach allowed to i) strongly involve local actors through collective meetings and ii) an original future study based on a retrospective study integrating long time changes.

Although there is an increasing interest in social sciences amongst policy makers in financial services and investment organisations, not enough is known about the way financial organisations and activities interact with their social environments. In particular, there is a need for more research into the way financial activities are integrated into broader social structures. This thesis will report on a comparative study analysing the practices of financial organisations and their employees in two very different social environments: the UK and Chile. From 38 in-depth interviews with financial practitioners in London, Edinburgh and Santiago de Chile about their job trajectories and experiences, it was possible to analyse the practices of financial organisations in the UK and Chile, with an emphasis on the way they interact with global financial trends and local distributions of power and resources. A sociological account of organisational processes such as recruitment, socialisation, staff allocation, promotion and organisation of work within firms in these countries allowed for description and analysis of the way firms’ practices are related to their social (structural, symbolic and institutional) contexts. The research shows that Chile’s position in the global financial market and local distribution of resources encourage more traditional organisational practices, especially in terms of recruitment, socialisation, staff allocation and promotion, as well as activities performed and the way services are provided. In the UK, on the other hand, all of the above-mentioned processes are more technical, formally designed and competitive.

Approved for public release, distribution is unlimited / This thesis explores using a direct pseudospectral method for the solution of optimal control problems with mixed dynamics. An easy to use MATLAB optimization package known as DIDO is used to obtain the solutions. The modeling of both low thrust interplanetary trajectories as well as aerocapture trajectories is detailed and the solutions for low thrust minimum time and minimum fuel trajectories are explored with particular emphasis on verification of the optimality of the obtained solution. Optimal aerocpature trajectories are solved for rotating atmospheres over a range of arrival Vinfinities. Solutions are obtained using various performance indexes including minimum fuel, minimum heat load, and minimum total aerocapture mass. Finally, the problem formulation and solutions for the mixed dynamic problem of low thrust trajectories with a terminal aerocapture maneuver is addressed yielding new trajectories maximizing the total scientific mass at arrival. / Lieutenant, United States Navy

Au cours du XXème siècle, l’élevage français a connu un formidable développement dont la poursuite se trouve actuellement fragilisé. L’effort de recherche sur la durabilité de l’élevage s’est focalisé sur la performance économique et environnementale, principalement au niveau de l’animal et de la ferme. Peu de travaux ont abordé les trois piliers de la durabilité à des échelles territoriales où les différentes filières animales se combinent. Une approche articulant l’élevage de ruminants et monogastriques à l’occupation du sol et à l’utilisation des ressources au niveau territorial fait actuellement défaut. Cette thèse développe une évaluation holistique de l’élevage dans les territoires métropolitains en mobilisant une batterie d’indicateurs abordant les contributions positives et négatives de l’élevage. Pour l’ensemble du territoire métropolitain, nous avons constitué trois bases de données à l’échelle départementale. La première base contient des indicateurs socioéconomiques, d’occupation du sol, et de production animale sur la période 1938-2010. La seconde base fournit pour 2010 des indicateurs de production animale et végétale. La troisième base fournit des indicateurs mesurant la contribution de l’élevage à la fourniture de services culturels, socioéconomiques et environnementaux. Avec la première base, nous avons modélisé les trajectoires d’intensification de l’élevage depuis 1938 et identifié les déterminants des dynamiques de changement de l’élevage. Avec la deuxième base, nous formalisé le métabolisme territorial de l’azote, duquel nous avons dérivés six indicateurs pour évaluer la durabilité de l’élevage. Avec la troisième base, nous avons modélisé le lien entre le niveau actuel de fourniture de services et les trajectoires d’intensification. Nos résultats révèlent une différentiation territoriale de l’intensification de l’élevage depuis 1938. Productivité et densité animale ont triplé dans les territoires de l’Ouest, et augmenté de 1.6 dans les territoires de l’Est et du Massif Central. Dans les territoires sans élevage, la surface fourragère principale a reculé de plus de la moitié, tandis que la taille des fermes a triplé et la productivité du travail a quadruplé. Le métabolisme territorial révèle un arbitrage entre autonomie en azote et productivité animale. Les impacts locaux (surplus azoté / ha) et globaux (émissions excrétion azoté / kg de produit) forment un arbitrage difficile à atténuer. L’analyse des contributions positives de l’élevage montre que les territoires ayant suivi une trajectoire herbagère fournissent des services sociaux, environnementaux et culturels; alors que les territoires hébergeant les élevages les plus productifs fournissent surtout des services socio-économiques (emplois). De par sa profondeur historique et sa couverture spatiale, cette thèse offre une analyse inédite de l’élevage et de ses performances dans les territoires. Elle apporte des connaissances pour identifier des leviers de durabilité pour l’élevage de demain. / The development of the livestock sector in the past century undergone a strong intensification. The current heterogeneity of livestock areas in France may have arisen from a spatial differentiation of intensification process. Different degrees of disconnection between livestock and land have resulted in contrasted levels of performance and impacts across areas. To date, a lot of research effort has been directed at measuring environmental impacts and economic performance of livestock systems at the farm level. Insufficient attention has been paid to the three dimensions of sustainability and to trade-offs among them. Existing livestock heterogeneities across areas also deserve more research. An approach that enables connecting livestock to land and resources, at regional level, could bring novel insights on the role of livestock in use and transformation of resources. The goal of this PhD was to develop a holistic assessment of livestock areas using multimetric indicators encompassing positive and negative contributions. We compiled three databases at the department level: i) database 1 was related to socioeconomic, land use, and production characteristics of 88 French departments, within an extensive time frame (1938-2010); ii) database 2 included data on crop, fodder and livestock production for year 2010; iii) database 3 included measures of provision of cultural, environmental and social services for 60 departments. With the first database, we created a typology of intensification trajectories based on a multivariate approach. With the second database, we assessed the nitrogen metabolism of livestock areas, based on the material flows accounting (MFA) approach, from which we derived indicators of performance and impacts to study synergies and trade-offs. With the third database, we studied the influence of past intensification on the current provision of services by the livestock sector. A multivariate approach was used to assess how different rates of change in intensification variables determined contrasted levels of services. First, we showed that the intensification of the French livestock sector was spatially differentiated and based on four trajectories, ranging from extensive to intensive livestock areas, and from crop specialized to areas where livestock had a small share of national production. Livestock productivity and stocking rates had a 3 fold increase in intensive areas, whereas extensive areas had a 1.6 fold increase. Crop specialized areas lose more than half of their original fodder area, and tripled the average farm size and more than quadrupled their labor productivity. Non-dominated livestock areas lose 30% of initial livestock population, and half of their initial fodder area. Second, the study of synergies and trade-offs revealed that gains in efficiency and economies of scale, often compromised other dimensions, e.g. through increased environmental impacts. The spatial analysis of relationship between performance and impacts revealed two types of synergies linked to the type of impact, either land or product-based. Both of which were in trade-off. Third, we showed that the provision of services was spatially structured and based on three types of service bundles, determined by different rates of change in intensification variables. Changes towards grazing systems resulted in higher provision of environmental and cultural services, whereas changes towards intensive systems resulted in higher levels of social services; but this was achieved at the cost of environmental services. This PhD thesis furthered the understanding on the temporal trajectories of livestock sector across areas in France. This knowledge could help to improve livestock sustainability. Our work provided knowledge on the drivers that shaped current intensification patterns and the provision of cultural, environmental and social services. It could be used to examine options for desirable longterm changes of the livestock sector.

Este estudo teve como ponto de partida o reconhecimento da realidade heterogênea do trabalho. O chamado trabalho informal é uma forma econômica que sempre coexistiu com as outras modalidades em países latino-americanos, o qual adverte que como atividade econômico-produtiva existia muito antes dos discursos sobre a perda significativa de vagas de emprego. A questão básica da pesquisa propôs analisar a construção das trajetórias de trabalho dos vendedores informais das ruas do centro de Cali, Colômbia; considerando um enfoque nos trabalhadores e suas experiências no trabalho informal, ou seja, naqueles trabalhos que não estão regulamentados pelo Estado ou dos quais não se recolhem impostos nem contam com proteção social (saúde e aposentadoria). Compreendendo as trajetórias de trabalho como o particular traço ou percurso que faz o indivíduo no espaço sociolaboral, que descreve as sucessivas posições que tem ocupado ao longo do tempo, desde sua inserção no mercado laboral (Orejuela & Correa, 2007, p.64); embora este percurso vá além de uma reconstrução das distintas atividades de trabalho e permita analisar elementos como as motivações e escolhas pessoais, os fatores macro e micro sociais, além da temporalidade. A pesquisa abordou um método qualitativo com perspectiva etnográfica que permitiu identificar as construções das trajetórias de trabalho em vendedores informais de rua do centro de Cali e junto com o trabalho de campo, um retrato sobre o trabalho informal nesse espaço. Participaram oito vendedores informais dos quais se obtiveram depoimentos orais, por meio de entrevista e conversa. As informações obtidas foram estudadas à luz da Análise Temática proposta na teoria das histórias de vida de Queiroz (1988). Foram estudadas individualmente as trajetórias para, em seguida, identificaram-se alguns elementos comuns. Considera-se através das narrativas dos vendedores, que as trajetórias de trabalho, organizam-se a partir de aquilo que as pessoas têm conseguido criar para, além de sobreviver, obter um sentido para a vida segundo o que fazem, construindo redes que lhes permitem movimentar o caminho segundo seus projetos e os valores atribuídos ao trabalho. A partir daí, definiram-se os temas que organizam as histórias de vida, tais como as transições, as redes, os projetos e os sentidos do trabalho, os quais se configuraram numa totalidade de vivências que dão sentido ao caminho no mundo laboral. Finalmente, identificou-se a complexidade das construções das trajetórias de trabalho, marcadas por elementos como os familiares, culturais e sociais, os 6 quais extrapolam o universo laboral, além de demonstrar que os contatos que as pessoas estabelecem durante o percurso, especificamente no centro da cidade, gera uma rede de solidariedade que os sustenta no trabalho informal. Outro aspecto importante nas considerações é a dificuldade de qualificar estes trabalhadores que continuamente encontram-se entre fronteiras permeáveis entre formas de trabalho formal-informal / This research takes into account the heterogeneous reality of work considering that informal jobs have been always part of the Latin American economic system, and have coexisted with other working arrangements. This suggests that informal activities have existed before the speeches on restructuring labor markets and unemployment. As research question I propose to analyze the work trajectories of informal street vendors in downtown Cali, Colombia; that is to say, those jobs that are not regulated by the State. Work trajectories are defined as \"the direct line or route that is followed by an individual in the social-space, which describes the successive positions he has held over time\" (Orejuela & Correa, 2007, p.64). However, this analysis is not just focused on the reconstruction of the various work activities since I also analyze other factors such as personal motivations, personal choices and macro-and micro social facts. I tackled this research from a qualitative method, which involves an ethnographic perspective that allowed me to identify the trajectories of informal street vendors. I selected eight vendors with whom interviews and discussions were conducted. The data obtained were analyzed based on the Thematic Analysis of life histories (Queiroz, 1988). Initially, the trajectories were studied individually, and then common elements were identified. From the venders´ narratives I found that the trajectories are organized not just as a way to survive but also as a way to have a purpose in life. They build networks that allow them to move toward their projects and give value to their works. Keeping this in mind I classified the trajectories by themes such as transitions, networks, projects, and sense of work, which are configured in a totality of experiences that give coherence to their jobs. Finally, I identified the complexity of developing those trajectories, which is affected by familiar, cultural and social contexts

A luta pelo ensino superior: com a voz, os evadidos é um estudo sobre a expansão do ensino superior no Brasil. Tem como objeto as falas dos alunos não concluintes provenientes, em sua maioria, das camadas desfavorecidas. Entre os objetivos do trabalho está a perspectiva de se refletir sobre a problemática da desistência a partir daquele que se evade, buscando, por meio de seus relatos e da identificação de suas percepções e expectativas, contribuir para o desenvolvimento de políticas institucionais, ações e atitudes passíveis de se antecipar ao fenômeno da evasão. A abordagem dos sujeitos da pesquisa deu-se primeiramente por meio de um questionário, para construção, em uma análise de natureza mais quantitativa, de um perfil ampliado do grupo. O formato da entrevista, aplicado a um número mais restrito de sujeitos, foi o instrumento utilizado para uma análise de natureza mais qualitativa. A fundamentação teórico-metodológica para construção das variáveis da pesquisa e leitura dos dados referenciou-se, em especial, nos conceitos de Bourdieu, Castel, Dubet e Lahire. A análise dos dados contempla diferentes momentos das trajetórias dos evadidos, a vida familiar e escolar e a passagem pela universidade, com destaque para o processo da desistência do ensino superior. Entre os fatores a serem destacados nesse percurso estão as vantagens e desvantagens acumuladas nas trajetórias que possibilitaram a cada qual chegar a um curso universitário, mas sem conseguir concluí-lo. Nos relatos podem-se observar os sentimentos de tristeza e decepção pela desistência e também o orgulho de ter ido tão longe, bem como os efeitos na vida de cada um deles, quanto ao tempo de graduação realizado. O texto ressalta ainda as dificuldades e os sentidos de poder falar sobre a experiência da evasão e destaca, por fim, os desafios para as instituições universitárias no sentido de garantir melhores condições de permanência. / The struggle for higher education: with the voice, the evaded is a study on the expansion of higher education in Brazil. It has as object the speeches of not graduating students from, mostly, the disadvantaged groups. Among the objectives of the work is the perspective of reflecting on the issue of desistance from the one who evades, seeking, through his reports and identifying his perceptions and expectations, to contribute to the development of institutional policies, actions and attitudes liable to anticipate the evasion phenomenon. The approach of the study subjects took place primarily by means of a questionnaire for building, in a more quantitative analysis of an extended profile of the group. The format of the interview, applied to a more restricted number of subjects, was the instrument used to a more qualitative nature analysis. The theoretical and methodological basis for the construction of research variables and reading of data is referenced, in particular, under the concepts of Bourdieu, Castel, Dubet and Lahire. The data analysis includes different times of the trajectories of evaded, the family and school life and the passage by the university, especially the higher education desistance process. Between the factors to be highlighted in this route are the advantages and disadvantages accumulated in the trajectories that enabled each one to get to a university course, but without being able to complete it. In the reports could be observed the feelings of sadness and disappointment at the desistance and also the pride of having gone so far, as well as, the effects on the lives of each of them, about the accomplished graduation time. The text also highlights the difficulties and sense of being able to discuss about the experience of evasion and it stands out, finally, the challenges for universities to ensure better conditions of staying.