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Otimização em Meteorologia: cálculo de perturbações condicionais não-lineares ótimas / Optimization in Meteorology: computation of conditional nonlinear optimal perturbationsLima, Jessé Américo Gomes de 11 May 2012 (has links)
Neste trabalho estudamos as aplicações do método do Gradiente Espectral Projetado (SPG) em Meteorologia nos campos de previsibilidade, estabilidade e sensibilidade. Inicialmente revisamos os Vetores Singulares Lineares (LSVs) e em seguida apresentamos a teoria das Perturbações Condicionais Não-Lineares Ótimas (CNOPs). Enquanto os métodos clássicos estão baseados no Modelo Tangente Linear, as CNOPs são uma formulação do mesmo problema baseado em Programação Não-Linear. As CNOPs são descritas na literatura como responsáveis por melhorias em relação aos métodos anteriores. Finalmente analisamos três exemplos de aplicação do método à problemas de previsibilidade, estabilidade e sensibilidade. / A revision about applications of Spectral Projected Gradient (SPG) in meteorology is done in the fields of predictability, stability and sensitivity. Initially we review about Linear Singular Vectos (LSVs) and we present the Conditional Nonlinear Optimal perturbations (CNOPs). While the classic methods are based on the Tangent Linear Model, CNOPs are another formulation of the problem based on Nonlinear Programming. CNOPs are described in bibliography as responsible by better results than older methods. Finally we analyze three applications in predictability, stability and sensibility.
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Variation of Feeding Regimes: Effects on Giant Panda (Ailuropoda melanoleuca) BehaviorSandhaus, Estelle Ann 03 December 2004 (has links)
Giant pandas in captivity are typically fed discrete amounts of highly concentrated food on a fixed time schedule, in addition to limited amounts of fresh bamboo throughout the day. In response to informal observations that these animals engage in a number of undesirable behaviors just prior to the predictable feeding of concentrated meals, we examined the existing feeding regime at the Research Base of Giant Panda Breeding in Chengdu, Peoples Republic of China. We sought to determine whether undesirable behaviors were occurring more frequently before the delivery of meals than at other times of day and whether modified feeding regimes would result in a more species-appropriate activity budget overall. As predicted, female giant pandas spent significantly more time engaged in door-directed/human-oriented behavior, stereotypic behavior, and non-stereotypic locomotion in the 30-minute periods prior to the feeding of concentrated meals. When placed on a modified feeding schedule in which frequency of bamboo provisioning was increased (total amount was held constant), significant differences were not found between study phases for the above-mentioned behaviors of interest, though a visual trend towards a decline in stereotypic behavior during the experimental phase was noted. Male pandas, when placed on a less predictable feeding schedule, did not exhibit significant behavioral differences in behaviors of interest between experimental phases or observation periods. These findings may be attributable in part to the low power inherent in the small sample size. However, visual trends that may be indicative of feeding anticipatory activity (FAA) were apparent. It appears that giant pandas, like many other animal species cited in the literature, are sensitive to periodic feeding regimes, though it is less clear as to which regime modifications will prove most beneficial.
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Predictability and prediction of tropical cyclones on daily to interannual time scalesBelanger, James Ian 03 July 2012 (has links)
The spatial and temporal complexity of tropical cyclones (TCs) raises a number of scientific questions regarding their genesis, movement, intensification, and variability. In this dissertation, the principal goal is to determine the current state of predictability for each of these processes. To quantify the current extent of tropical cyclone predictability, we assess probabilistic forecasts from the most advanced global numerical weather prediction system to date, the ECMWF Variable Resolution Ensemble Prediction System (VarEPS). Using a new false alarm clustering technique to maximize the utility of the VarEPS, the ensemble system is shown to provide well-calibrated probabilistic forecasts for TC genesis through a lead-time of one week, and pregenesis track forecasts with similar skill compared to the VarEPS's postgenesis track forecasts. To quantify the predictability of TCs on intraseasonal time scales, forecasts from the ECMWF Monthly Forecast System (ECMFS) are examined for the North Atlantic Ocean. From this assessment, dynamically based forecasts from the ECMFS provide forecast skill exceeding climatology out to weeks three and four for portions of the southern Gulf of Mexico, western Caribbean and the Main Development Region. Forecast skill in these regions is traced to the model's ability to capture correctly the variability in deep-layer vertical wind shear, the relative frequency of easterly waves moving through these regions, and the intraseasonal modulation of the Madden-Julian Oscillation.
On interannual time scales, the predictability of TCs is examined by considering their relationship with tropical Atlantic easterly waves. First, a set of easterly wave climatologies for the CFS-R, ERA-Interim, ERA-40, and NCEP/NCAR Reanalysis are developed using a new easterly wave-tracking algorithm. From the reanalysis-derived climatologies, a moderately positive and statistically significant relationship is seen with tropical Atlantic TCs. In relation to large-scale climate modes, the Atlantic Multidecadal Oscillation (AMO) and Atlantic Meridional Mode (AMM) exhibit the strongest positive covariability with Atlantic easterly wave frequency. Besides changes in the number of easterly waves, the intensification efficiency of easterly waves has also been evaluated. These findings offer a plausible physical explanation for the recent increase in the number of NATL TCs, as it has been concomitant with an increasing trend in both the number of tropical Atlantic easterly waves and intensification efficiency.
The last component of this dissertation examines how the historical variability in U.S. landfalling TCs has impacted the annual TC tornado record. To reconcile the inhomogeneous, historical tornado record, two statistical tornado models, developed from a set of a priori predictors for TC tornado formation, are used to reconstruct the TC tornado climatology. While the synthetic TC tornado record reflects decadal scale variations in association with the AMO, a comparison of the current warm phase of the AMO with the previous warm phase period shows that the median number of tornadoes per Gulf TC landfall has significantly increased. This change likely reflects the increase in median TC size (by 35%) of Gulf landfalling TCs along with an increased frequency of large TCs at landfall.
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FACTORS RELATING TO HPV BEHAVIORS OF FEMALE COLLEGE STUDENTSPeritore, Nicole Rachael 01 January 2012 (has links)
This study examined the knowledge, sources of information, reasons for and against Gardasil® uptake, and possible relationships between unhealthy behaviors and vaccination for undergraduate college females at a public university. Utilizing an online survey, 2400 random students were emailed as well as recruited through online classes. The final sample size was 516 females. The study determined how many participants had been vaccinated and their rationale for or against vaccination. The majority of study participants were knowledgeable about HPV and Gardasil®. The primary sources of information about HPV and Gardasil® were doctors and television; however parents and friends were also common sources of information. Predictors for HPV inoculation included race, the belief that the vaccine would protect against HPV, alcohol use, and engagement in anal intercourse. Over 50% of participants had received at least one dose of Gardasil®, and 82% had completed the series. The most common rationale for not getting the vaccine, or not completing the vaccination series, was concern about side effects. The most common rationale for completing the vaccination or intending to complete the series was protection from cervical cancer. In conclusion, there is a continued need provide health education about HPV and HPV vaccination for college females.
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The eviction due to precarious occupation in the light of the Fourth Civil Cassation Plenaries / El desalojo por ocupación precaria a la luz del Cuarto Pleno Casatorio CivilRisco Sotil, Luis Felipe del 12 April 2018 (has links)
In this article the author show us the situation of the precarious along the eviction process where they are involved. Likewise, he tell us regarding the cumbersome situation and the null legal certainty that existed about this theme before the emission of the Fourth Civil Cassation Plenaries.After the Plenaries, the author points, were given rules to identify this matterand reach uniforms conclusions by judges, which represents an advance in the predictability of the judicial decisions about the eviction by precarious occupation. / En el presente artículo el autor no presenta la situación de los precarios y los procesos de desalojos donde se ven involucrados. Asimismo, nos cuenta acerca de la situación engorrosa y la nula seguridad jurídica que existía acerca del tema antes de la emisión del Cuarto Pleno Casatorio Civil. A partir del Pleno, señala el autor, se dieron reglas para identificar este problema y llegar a conclusiones uniformes por parte de los jueces, lo que representa un avance en la predictibilidad de las resoluciones judiciales sobre el desalojo por ocupación precaria.
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A utilização do ENADE como métrica de qualidade dos cursos de ensino superiorMenaldo, Bruno Eduardo 06 February 2018 (has links)
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Previous issue date: 2018-02-06 / Para analisar a nota obtida pelas instituições no ENADE como métrica de qualidade são realizados exercícios levando em consideração três períodos de avaliação dos cursos de Administração, Ciências Econômicas, Ciências Contábeis e Engenharia. Os resultados mostram que as instituições menores apresentam uma maior variabilidade das notas em Formação Geral e em Conhecimento Especifico. Adicionalmente a mudança das notas de um período para o seguinte é mais intenso, positiva ou negativa, nas instituições menores. Uma parcela significativa da variação da nota de um período para o outro é concedida a fatores não persistentes, ou seja, elementos que estão fora da gestão da instituição e que tendem a ser revertidos no período seguinte. As instituições melhores posicionadas no ranking têm uma probabilidade maior de permanecerem bem colocadas, esse cenário se intensifica para as instituições privadas. Já as demais têm uma probabilidade baixa de se manterem na mesma colocação, podendo ter uma melhora ou piora de posição. O Questionário Socioeconômico do Enade, que visa capturar a percepção dos alunos e compor 15% do indicador do Conceito Preliminar do Curso (CPC), se mostra ineficiente como métrica de qualidade da instituição, pois 48% dos itens do formulário aparecem correlacionados negativamente com as notas. / To analyze the score of institutions on ENADE (National Exam of Student Performance) as a measure of quality, some methodologies are applied considering three periods of evaluation on courses of administration, economic sciences, accounting sciences and engineering universities. The results indicate that small institutions present greater variability of scores in general education and specific knowledge. Additionally, the score variation from one period to the next is more intense, positively or negatively, in the small institutions. A significant share of the score variation from one period to the next is attributed to non-persistent factors, which are elements not managed by the institutions and which tend to be reverted in the next period. The institutions that are in a better position in the ranking have greater probability to continue well ranked, and this scenario is more intense for private institutions. On the other hand, the other institutions have a low probability to keep their rank positions, which can get better or worse. The socioeconomic questionnaire of ENADE, which is responsible to capture the students’ perception and makes up 15% of the CPC (Preliminary Course Concept) indicator, showed to be inefficient as a measure of the institution quality, since 48% of total questions are negatively correlated with the scores.
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Prix des actifs et actifs sans prix / Asset Prices and Priceless AssetsPénasse, Julien 02 December 2014 (has links)
Cette thèse étudie plusieurs aspects de la dynamique du rendement des actifs. Les trois premiers chapitres ont pour objet la formation des prix sur le marché de l'art. Le premier chapitre établit que les prix peuvent s'écarter temporairement, et de manière partiellement prévisible, de la valeur fondamentale. Cet article a été publié dans Economics Letters (Volume 122, Issue 3, pp. 432-434) et a été écrit avec Christophe Spaenjers et Luc Renneboog. Le chapitre 2 étudie la vitesse de transmission de l'information dans les prix agrégés du marché de l'art. Le chapitre 3 analyse la corrélation entre prix et volume et étaye des éléments concordant avec une hypothèse de bulles. Il a été écrit avec Luc Renneboog. Le chapitre 4 s'attache à la modélisation empirique de la prédictibilité d'indices boursiers sur quinze pays industrialisés. Il propose de combiner l'information donnée par chaque pays de façon à améliorer le pouvoir prédictif. / The doctoral thesis studies several aspects of asset returns dynamics. The first three chapters focus on returns in the fine art market. The first chapter provides evidence for the existence of a slow-moving fad component in art prices that induces short-term return predictability. The article has been published in Economics Letters (Volume 122, Issue 3, pp. 432-434), and was written together with Christophe Spaenjers and Luc Renneboog. Chapter 2 investigates how fast is information incorporated into aggregate art prices. Chapter 3 studies price-volume dynamics in the art market and documents evidence of bubble patterns in prices and is written with Luc Renneboog. Chapter 4 proposes a Bayesian estimation procedure that makes efficient use of cross-sectional information, and revisits the return predictability literature.
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Exécution prédictible sur processeurs pluri-coeurs / Predictable execution on many-core processorsPerret, Quentin 25 April 2017 (has links)
Dans cette thèse, nous étudions l’adéquation de l’architecture distribuée des processeurs pluricoeurs avec les besoins des concepteurs de systèmes temps réels avioniques. Nous proposons d’abord une analyse détaillée d’un processeur sur étagère (COTS), le KALRAY MPPA®-256, et nous identifions certaines de ses ressources partagées comme étant les goulots d’étranglement limitant à la fois la performance et la prédictibilité lorsque plusieurs applications s’exécutent. Pour limiter l’impact de ces ressources sur les WCETs, nous définissons formellement un modèle d’exécution isolant temporellement les applications concurrentes. Son implantation est réalisée au sein d’un hyperviseur offrant à chaque application un environnement d’exécution isolé et assurant le respect des comportements attendus en ligne. Sur cette base, nous formalisons la notion de partition comme l’association d’une application avec un budget de ressources matérielles. Dans notre approche, les applications s’exécutant au sein d’une partition sont garanties d’être temporellement isolées des autres applications. Ainsi, étant donné une application et son budget associé, nous proposons d’utiliser la programmation par contraintes pour vérifier automatiquement si les ressources allouées à l’application sont suffisantes pour permettre son exécution de manière satisfaisante. Dans le même temps, dans le cas où un budget est effectivement valide, notre approche fournit un ordonnancement et un placement complet de l’application sur le sous-ensemble des ressources du processeurallouées à sa partition. / In this thesis, we study the suitability of the distributed architecture of many-core processors for the design of highly constrained real-time systems as is the case in avionics. We firstly propose a thorough analysis of an existing COTS processor, namely the KALRAY MPPA®-256, and we identify some of its shared resources to be paths of interference when shared among several applications. We provide an execution model to restrict the access to these resources in order to mitigate their impact on WCETs and to temporally isolate co-running applications. We describe in detail how such an execution model can be implemented with a hypervisor which practically provides the expected property of temporal isolation at run-time. Based on this, we formalize a notion of partition which represents the association of an application with a resource budget. In our approach, an application placed in a partition is guaranteed to be temporally isolated from applications placed in other partitions. Then, assuming that applications and resource budgets are given,we propose to use constraint programming in order to verify automatically whether the amount of resources requested by a budget is sufficient to meet all of the application’s constraints. Simultaneously, when a budget is valid, our approach computes a schedule of the application on the subset of the processor’s resources allocated to it.
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Analyse de la variabilité atmosphérique à l'échelle intrasaisonnière et de sa prévisibilité au dessus de la côte guinéenne et de l'Afrique Centrale / Analysis of the Atmospheric Variability at Intraseasonal scale and his predictability over the Guinean coast and Central AfricaKamsu Tamo, Pierre Honoré 01 December 2017 (has links)
Cette étude s'inscrit dans le cadre de la documentation de la variabilité intrasaisonnière atmosphérique et l'analyse de la prévisibilité sur les régions Afrique Centrale et Golfe de Guinée. Elle porte sur les saisons de l'année pour lesquelles la ZCIT est au dessus de l'équateur. Des travaux menés distinctement sur les mois de Mars à Juin et de Septembre à Novembre, il ressort que les activités convective et pluvieuse au cours de ces saisons sont régies par trois modes principaux de variabilité assez proches. Au cours de ces deux saisons, les systèmes individuels générateurs de pluie se déplacent d'est en ouest, et leur activité est régulée par des enveloppes convectives se déplaçant vers l'est. Des analyses spécifiques ont mis en lumière la forte empreinte de signaux équatoriaux de type onde de Kelvin se propageant vers l'est et dont les phases régulent l'organisation des systèmes convectifs. L'impact relatif d'ondes équatoriales se propageant vers l'ouest (Rossby en particulier) et celui d'advections de masses d'air méditerranéennes n'est pas à négliger, d'autant plus qu'elles sont susceptibles d'interagir avec les ondes de Kelvin, et donc de moduler les phases de l'activité convective. Les forçages externes ainsi identités constituent des sources potentielles de prévisibilité pour les modes intrasaisonniers mis en évidence. Utilisant les données de la base multi-modèle TIGGE, l'analyse de la prévisibilité de chacun des modes principaux de variabilité est réalisée. Se focalisant sur les phases spécifiques de ces modes, les scores obtenus augurent une prévisibilité au delà de 10 jours surtout pour des prévisions initialisées lorsque les principales sources sont actives. / In this study we document the intraseasonal variability of the tropical convection and its predictability during the rainy season over the Central Africa and the Gulf of Guinea. Here, our study mainly focuses on seasons of the year for which the ITCZ is north of the equator. Based separate studies carried out on March to June and September to November seasons, we are able to identify three main modes of variability that modulate tropical convection and rainfall in West and Central Africa. During these two seasons, while individual rain-producing systems move westward, their activity is highly modulated by eastward propagating subregional and regional scale systems. Results of detailed analysis indicate the coupling between tropical convection and equatorial Kelvin wave in the region. The phases of these eastward propagating signals play an important role by regulating the organization of convective systems. Moreover, the role played by westward propagating signals (Rossby wave in particular) and Mediterranean air intrusion needs to be taken into account. These systems by interacting with Kelvin wave, may modulate the phases of convective activity in the region. Therefore, external forcing associated with these systems can be useful to the predictability of the intraseasonal modes the region. A multi model diagnostic study is performed using data available from the TIGGE project in order to evaluate the predictability of each of the main modes of variability. For a typical phase of these modes, there seems to be a statistically significant skill associated with predictability of beyond 10 days, especially for predictions initiated from active main sources.
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L'influence des coups de vent d'ouest dans le Pacifique équatorial sur El Niño : origines atmosphériques et impacts océaniques / The influence of equatorial pacific westerly wind events on El Niño : atmospheric origins and oceanic impactsPuy, Martin 18 February 2016 (has links)
Les coups de vent d’ouest (WWEs) issu de la variabilité synoptique atmosphérique jouent un rôle crucial dans les irrégularités d’ENSO en contribuant au déclenchement et au développement de sa phase chaude, El Niño. Les WWEs sont des événements haute fréquence peu prévisibles et dont les origines atmosphériques restent encore débattues. Dans le but d’affiner la prévisibilité d’ENSO, cette thèse caractérise la part stochastique de la part prévisible des WWEs ainsi que de leur réponse océanique et couplée. Dans une première partie, j’ai relié l’occurrence et les caractéristiques des coups de vent à des phénomènes de grande échelle comme l'oscillation de Madden-Julian, les ondes de Rossby atmosphériques et ENSO, à partir d’analyse d’observations. Ensuite, la forte sensibilité de la réponse océanique des WWEs à l’état de l’océan a été mise en évidence grâce à une série de simulations océaniques forcées. Finalement, une simulation d’ensemble réalisée avec un modèle couplé océan-atmosphère a permis d'explorer le rôle des WWEs dans l’évolution contrastée des années 1997,2014 et 2015 qui présentaient des conditions similaires et favorables au déclenchement d'El Niño. Les résultats de ce travail montrent que la stochasticité des WWEs aboutit à une limitation intrinsèque de la prévisibilité des caractéristiques d’El Niño. / Equatorial Pacific Westerly Wind Events (WWEs) impact ENSO evolution through their oceanic response and strongly contribute to its irregularities. WWEs are characterized by episodes of anomalous, short-lived, strong westerlies developing over the western Pacific warm pool. This thesis characterize the atmospheric origins and the oceanic and coupled impacts of these events in order to improve ENSO prediction. First, we show that, at intraseasonnal timescale, the Madden-Julian oscillation and the convectively coupled Rossby waves provide favourable conditions for the occurence of WWEs and confirm their modulation by ENSO at interannual timescale. Oceanic simulation with idealized forcing further allow characterizing and understanding the modulation of the SST response to WWE by the oceanic background state. Finally, The role of WWEs in the contrasted evolution of El Niño in 1997,2014 and 2015, which exhibited favourable conditions for El Niño to develop, is explored in ensemble simulations using a coupled ocean-atmosphere model. It is shown that the stochasticity of the WWEs acts as a strong limitation for ENSO predictability.
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