• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 8
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 15
  • 15
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

河床攪乱頻度を指標とした生息場評価による瀬・淵構造の変質に関する考察

田代, 喬, TASHIRO, Takashi, 辻本, 哲郎, TSUJIMOTO, Tetsuro 02 1900 (has links)
No description available.
2

Análise espaço-temporal do risco à inundação na área urbana do município de Uruguaiana/RS / Analysis space-time of risk to flooding in the city of Uruguaiana / RS

Aimon, Jonatas Giovani Silva 01 February 2017 (has links)
Over the years, man's use of nature has led to significant episodes of human and material loss, especially the last decade due to the advance of urbanization, which has been initiated by the search for better employment opportunities for the rural population. The municipality of Uruguaiana has its origin linked to the proximity of the Uruguay River, and trade with Argentina and Uruguay. As a result of this history, and the need for studies on natural hazards and planning, this study aims to analyze the spatial-temporal dynamics of flood risk in the urban area of the city of Uruguaiana / RS. Data from the municipal government, National Water Agency (ANA) were used as information base, applying the deductive method, combined with previous knowledge with knowledge based on other bibliographical references. For the construction of the Digital Terrain Model, the Arcgis 10.1® Top to Raster tool was used. The hazard, exposure to flood threat, was obtained by using the logarithmic function on the sets of observations extracted in the previous study of the maximum floods (above the 48 m altitude). Soon, their respective boundaries were obtained in the field for the classes 2/5/25/100 years (TR). Vulnerability, potential for losses and damages was mapped on the basis of field surveys, traversing the areas affected by the calculated TR, being evaluated the real estate of the urban area and the spatial distribution of the same, being after delimited small areas in the areas affected by the flood, Classified according to the Very High/High/Medium/Low Vulnerability classes. The detailing of the local topography revealed that the floods reaching the population are mainly due to the extrapolation of the water level in the Arroio Cacaréu and Arroio Salso de Cima. The mapping of the 245.63 ha, revealed a great differentiation within the same municipality, social segregation is clearly manifested in space. Most households with high (22.34%) or very high (8.40%) vulnerability, are concentrated near Arroio Cacaréu in the neighborhoods Francisca Tarrago and Cabo Luis Quevedo. After crossing the information plans were found 2,205 residences, with potential risk ranging from Low to Very High. Regarding the amount found, it is worth noting the need for attention to the households found in situations of High and Very High risk, totaling about 34.96% of the sample analyzed for study. / Ao longo dos anos o modo como o homem utiliza a natureza, tem ocasionado significativos episódios de perdas humanas e materiais, em especial a última década devido ao avanço da urbanização, iniciada pela saída a procura por melhores oportunidades de emprego da população rural. O município de Uruguaiana tem a sua origem ligada a proximidade com o Rio Uruguai, e o comercio com a Argentina e Uruguai. Em decorrência desse histórico, e a necessidade de estudos sobre riscos naturais e planejamento, este trabalho tem por objetivo analisar a dinâmica espaço-temporal do risco de inundação na área urbana do município de Uruguaiana/RS. Foram utilizados como base de informações dados da prefeitura municipal, Agência Nacional de Águas (ANA), aplicando-se o método dedutivo, aliado ao conhecimento prévio com conhecimento construído com base em outras referências bibliográficas. Para a construção do Modelo Digital de Terreno, utilizou-se a ferramenta Topo to Raster do Arcgis 10.1®. O perigo, exposição a ameaça de inundação, foi obtido utilizando-se como metodologia o cálculo dos Tempos de retorno (TR), aplicando-se a função logarítmica sobre os conjuntos de observações extraídas no estudo prévio das máximas inundações ocorridas (acima da altitude 48m). Logo foram obtidas suas respectivas cotas limite no terreno para as classes 2/5/25/100 anos (TR). A vulnerabilidade, potencial de perdas e danos foi mapeada com base nos levantamentos de campo, percorrendo as áreas atingidas pelos TR calculados, sendo avaliados os imóveis da área urbana e a distribuição espacial dos mesmos, sendo após delimitadas pequenas zonas nas áreas atingidas pela inundação, classificadas de acordo com as classes de Vulnerabilidade Muito Alta/Alta/Média/Baixa. O detalhamento da topografia local revelou, que as inundações que atingem a população decorrem principal pela extrapolação do nível das águas nos Arroios Cacaréu e Arroio do Salso de Cima. O mapeamento dos 245,63 ha, revelou uma grande diferenciação dentro do mesmo município, a segregação social é nitidamente manifestada no espaço. A maioria dos domicílios com Alta (22,34%) ou Muito Alta (8,40%) vulnerabilidade, concentram-se próximo ao Arroio Cacaréu nos bairros Francisca Tarrago e Cabo Luis Quevedo. Após o cruzamento dos planos de informação foram encontradas 2.205 residências, com risco potencial variando de Baixo à Muito Alto. Em relação ao montante encontrado salienta-se a necessidade de atenção para os domicílios encontrados em situação de Alto e Muito Alto risco, totalizando cerca de 34,96 % da amostra analisada para estudo.
3

An Assessment of the river ice break-up season in Canada

Von de Wall, Simon Julius 20 December 2011 (has links)
A return-period analysis of annual peak spring break-up and open-water levels for 136 Water Survey of Canada hydrometric stations was used to classify rivers across Canada and to assess the physical controls on peak break-up water-levels. According to the peak water-level river-regime classification and subsequent analysis, 32% of rivers were classified as spring break-up dominated, characterized by low elevations and slopes and large basin sizes while 45% were open-water dominated and associated with alpine environments of high elevations and channel slopes, and smaller basin sizes. The remaining 23% of rivers were classified as a mixed regime. A spatial and temporal analysis (1969-2006) of the river ice break-up season using hydrometric variables of timing and water levels, never before assessed at the northern Canada-wide scale, revealed significant declines in break-up water levels and significant trends towards earlier and prolonged break-up in western and central Canada. The spatial and temporal influence of air temperature on break-up timing was assessed using the spring 0°C isotherm, which revealed a significant positive relationship but no spatial patterns. In the case of major ocean/atmosphere oscillations, significant negative (positive) correlations indicate that break-up occurs earlier (later) during the positive phases of the Pacific North American Pattern (El Niño Southern Oscillation) over most of western Canada. Fewer significant positive correlations show that break-up occurs later during the positive phases of the Arctic Oscillation and North Atlantic Oscillation in eastern Canada. / Graduate
4

Analýza nárazů větru na území České republiky / Analysis of wind gusts over the area of the Czech Republic

Pop, Lukáš January 2015 (has links)
The Ph.D. thesis deals with extreme wind gust analysis over the area of the Czech Republic. The first part of the thesis deals with processing of wind measurements, in particular maximum wind gusts measurements. Analysis of high-frequency wind measurement using 3-D sonic anemometer on the Kopisty station is included. Homogenization of the highest daily wind gusts was performed. Descriptive statistical analysis of measured wind gust values was performed. The following part of the thesis describes statistical theory of extreme values and discusses its applicability to wind gust data. Some theoretical findings were obtained. Numerous numerical experiments were performed focused on evaluation of proposed method. In the last part of the thesis station measurements were processed using the proposed methods and a model of dependence between extreme and mean wind climate was derived. The model was applied to the map of mean wind climate calculated earlier on the Institute of Atmospheric Physics and thus a map of extreme wind climate was obtained. The accuracy of this map was estimated. The map was compared with other maps of extreme wind calculated by other authors earlier.
5

Estudio de la factibilidad de un proyecto inmobiliario orientado al nivel socioeconómico C en el distrito de Miraflores – Arequipa / Feasibility study of a real estate project oriented to socioeconomic level C in the district of Miraflores - Arequipa

Arredondo Gonzales, Juan Enrique, Ccama Casas, Jhosemar, Villanueva Garro, Ronal Mayco 25 February 2022 (has links)
Pese a la volátil coyuntura que atraviesa nuestro país por la pandemia y un gobierno incierto, la venta de viviendas y sus precios se han mantenido estables desde finales del 2020, presentándose la oferta inmobiliaria como un “Mercado Saludable”. Sin embargo, este mismo contexto, nos exige ser muy cuidadosos con las expectativas y velocidad de ventas, disponibilidad y precios de materiales en el mercado y la capacidad de respuesta frente a las contingencias que puedan presentarse durante el desarrollo y puesta en marcha del proyecto inmobiliario “Torre Alba I”, cuyo público objetivo es el nivel socioeconómico C, del distrito de Miraflores en la ciudad y departamento de Arequipa. Con el fin de hacer viable este proyecto inmobiliario denominado “Torre Alba I”, el presente trabajo de investigación tiene como objetivo demostrar su factibilidad económica, considerando que existe una importante demanda efectiva de viviendas para los sectores socioeconómicos B y C. En consecuencia, se planteará un proyecto atractivo para los potenciales compradores a través del estudio de mercado y una estrategia de diferenciación enfocada. Se presentará el análisis especifico del proyecto en materia de rentabilidad económica, mediante la realización del flujo de caja, demostrando la factibilidad con resultados de un VAN+ y TIR+. Posteriormente, se presentarán las interpretaciones de los resultados obtenidos, concluyendo con la declaración de factibilidad y generación de valor económico y social en el desarrollo urbano del distrito. / Despite the volatile situation that our country is going through due to the pandemic and an uncertain government, the sale of homes and their prices have remained stable since the end of 2020, presenting the real estate offer as a "Healthy Market". However, this same context requires us to be very careful with the expectations and speed of sales, availability and prices of materials in the market and the ability to respond to contingencies that may arise during the development and start-up of the real estate project "Torre Alba I", whose target audience is socioeconomic level C, of the district of Miraflores in the city and department of Arequipa. In order to make viable this real estate project called "Torre Alba I", the present research work aims to demonstrate its economic feasibility, considering that there is an important effective demand for housing for socioeconomic sectors B and C. Consequently, an attractive project for potential buyers will be proposed through market research and a focused differentiation strategy. The specific analysis of the project in terms of economic profitability will be presented, through the realization of the cash flow, demonstrating the feasibility with results of a NPV + and IRR +. Subsequently, the interpretations of the results will be presented, obtained concluding with the declaration of feasibility and generation of economic and social value in the urban development of the district. / Trabajo de investigación
6

Modélisation multi-échelle de l'aléa pluviométrique et incertitudes associées - Application à la région des Cévennes. / Multi-scale modelling of rainfall hazard and related uncertainties - Application to the Cévennes region

Melese, Victor 15 February 2019 (has links)
La thèse présentée s'intéresse à la modélisation de l'aléa pluviométrique dans la région du Sud-Est de la France centrée sur les Cévennes. Cette région connait régulièrement des crues rapides et très localisées appelées crues éclair qui ont des impacts socio-économiques considérables. Une mesure statistique de l'aléa est la fréquence d'occurrence ou, de manière équivalente, la période de retour. La pluie étant un phénomène qui s'accumule non uniformément dans le temps et dans l'espace, l'aléa pluviométrique est une variable multi-échelle. Cette thèse vise à en proposer une modélisation intégrée pour la région du Sud-Est de la France, c'est à dire valide pour le continuum d'échelles spatio-temporelles.La première partie de ces travaux permet de comprendre quel cadre d'inférence est le plus adapté à cette modélisation. La seconde partie propose un modèle permettant d'exprimer l'aléa pluviométrique sur le continuum d'échelles spatio-temporelles. Enfin, le troisième partie propose un cadre de quantification multi-échelle (en temps et en espace) de fréquence d'occurrence d'un événement pluviométrique donné ainsi que la quantification des incertitudes associées / This thesis aims at modelling the rainfall hazard in a mountainous region of southeastern France centered on the Cévennes massif. This region undergoes intense rainfall events leading to flash floods, which have considerable socio-economics impacts. A statistical measure of hazard is the frequency of occurrence, or equivalently the return period. Since rainfall accumulates in both time and space, rainfall hazard in a multi-scale variable. This thesis propose a generic framework for rainfall hazard modelling over the continuum of spatio-temporal scales.The first part of this work allows to determine which is the most relevant statistical framework. The second part proposes a multi scale modelling of rainfall hazard for the region. Finally, the third part allows the multi-scale quantification of the frequency of occurrence of a given storm and of the related uncertainties.
7

Approche bayésienne de la construction d'intervalles de crédibilité simultanés à partir de courbes simulées

Lapointe, Marc-Élie 07 1900 (has links)
Ce mémoire porte sur la simulation d'intervalles de crédibilité simultanés dans un contexte bayésien. Dans un premier temps, nous nous intéresserons à des données de précipitations et des fonctions basées sur ces données : la fonction de répartition empirique et la période de retour, une fonction non linéaire de la fonction de répartition. Nous exposerons différentes méthodes déjà connues pour obtenir des intervalles de confiance simultanés sur ces fonctions à l'aide d'une base polynomiale et nous présenterons une méthode de simulation d'intervalles de crédibilité simultanés. Nous nous placerons ensuite dans un contexte bayésien en explorant différents modèles de densité a priori. Pour le modèle le plus complexe, nous aurons besoin d'utiliser la simulation Monte-Carlo pour obtenir les intervalles de crédibilité simultanés a posteriori. Finalement, nous utiliserons une base non linéaire faisant appel à la transformation angulaire et aux splines monotones pour obtenir un intervalle de crédibilité simultané valide pour la période de retour. / This master's thesis addresses the problem of the simulation of simultaneous credible intervals in a Bayesian context. First, we will study precipation data and two functions based on these data : the empirical distribution function and the return period, a non-linear function of the empirical distribution. We will review different methods already known to obtain simultaneous confidence intervals of these functions with a polynomial basis and we will present a method to simulate simultaneous credible intervals. Second, we will explore some models of prior distributions and in the more complex one, we will need the Monte-Carlo method to simulate simultaneous posterior credible intervals. Finally, we will use a non-linear basis based on the angular transformation and on monotone splines to obtain valid simultaneous credible intervals for the return period.
8

Snow avalanche hazard assessment in the French Alps using a combination of dendrogeomorphic and statistical approaches / Caractérisation de l'aléa avalancheux dans les Alpes françaises : combinaison d'approches dendrogéomorphologique et statistique

Schläppy, Romain 23 April 2014 (has links)
Les avalanches sont susceptibles d’affecter le réseau routier et les infrastructures bâties, mettant en péril la population. L’extension des avalanches est généralement évaluée à l’aide de modèles physiques et/ou statistiques. Ces modèles sont très performants pour simuler des événements relativement fréquents, cependant, les incertitudes augmentent dès lors que l’on considère des événements plus rares. Il est donc indispensable de valider les procédures de modélisation afin de confirmer les prédictions qui en découlent. Dans ce travail, la dendrogéomorphologie a été utilisée comme un outil de validation. Cette approche se fonde sur le fait que les arbres forment un cerne de croissance par année et que les individus affectés par des processus naturels enregistrent l’évidence d’une perturbation dans leurs cernes. Cette thèse a permis de proposer une nouvelle approche pour l’identification des événements avalancheux fondée sur l’expertise du dendrogéomorphologue et d’évaluer la qualité de l’approche dendrogéomorphologique. Il a également été possible de réaliser une validation croisée entre des avalanches extrêmes prédites par un modèle statistique-dynamique et des informations sur des périodes de retour d’avalanches similaires obtenues à l’aide de l’approche dendrogéomorphologique. Les résultats montrent une très bonne concordance pour des événements dont la période de retour est égale ou inférieure à 300 ans. Finalement, une analyse des relations statistiques avalanche-climat a montré que les arbres enregistrent préférentiellement les événements qui ont eu lieu durant des épisodes froids associés à des tempêtes hivernales accompagnées de fortes précipitations. / Snow avalanches are a significant natural hazard that impact roads, structures and threaten human lives in mountainous terrain. The extent of avalanches is usually evaluated using topographic or statistic models. These models are well capable to simulate contemporary events, but uncertainties increase as soon as longer return periods are investigated. Thus, there is a real need for validation of modelling procedures to corroborate model predictions. In the present work, dendrogeomorphology has been used as a validation tool. This approach is based on the fact that trees affected by mass movements record the evidence of geomorphic disturbance in their growth-ring series and thereby provide a precise geochronological tool for the reconstruction of past mass movement activity. This PhD thesis presents a new tree-ring-based semi-quantitative approach for the identification of avalanche events based on the analytical skills of the dendrogeomorphic expert and proposes an evaluation of the completeness of tree-ring records. Furthermore, this work proposes the first cross-validation of high return period avalanches derived from a locally calibrated statistical-dynamical model and the long-term, higher-return period information gathered from tree-ring records. Comparison of relations between runout distances and return periods between both approaches shows very good agreement for events with return periods of < 300 yr. Finally, a statistical analysis of avalanche-climate relations suggests that tree rings preferentially record events that occurred during cold winter storms with heavy precipitation.
9

Development of a flood-frequency model for the river basins of the Central Region of Malawi as a tool for engineering design and disaster preparedness in flood-prone areas

Laisi, Elton 02 1900 (has links)
Since 1971, a number of flood frequency models have been developed for river basins in Malawi for use in the design of hydraulic structures, but the varied nature of their results have most often given a dilemma to the design engineer due to differences in magnitudes of calculated floods for given return periods. All the known methods for flood frequency analysis developed in country so far have not used a homogeneity test for the river basins from which the hydrological data has been obtained. This study was thus conducted with a view to resolving this problem and hence improve the design of hydraulic structures such as culverts, bridges, water intake points for irrigation schemes, and flood protection dykes. In light of the above, during the course of this study the applicability of existing methods in the design of hydraulic structures was assessed. Also, the study investigated how land use and land cover change influence the frequency and magnitude of floods in the study area, and how their deleterious impacts on the socio-economic and natural environment in the river basins could be mitigated / Environmental Sciences / M. Sc. (Environmental Management)
10

Contributions à l'évaluation des risques en assurance tempête et automobile / Contributions to risk assessment in wind storm and car insurance

Mornet, Alexandre 30 September 2015 (has links)
Dans cette thèse, nous étudions la garantie tempête consacrée aux dommages causés par le vent et un développement de l'assurance comportementale à travers le risque automobile. Nous associons des informations extérieures comme la vitesse du vent aux données de l'assurance. Nous proposons la construction d'un indice tempête pour compléter et renforcer l'évaluation des dégâts causés par les tempêtes majeures. Nous définissons ensuite un partage du territoire français en 6 zones tempêtes, dépendant des corrélations extrêmes de vent, pour tester plusieurs scénarios. Ces différents tests et considérations nous permettent d'améliorer notre indice tempête. Nous nous appuyons sur les modèles de la théorie des valeurs extrêmes pour montrer l'impact de la variabilité sur le calcul des périodes de retour et besoins en fonds propres. Nous soulignons ainsi les difficultés rencontrées pour dégager des résultats robustes en lien avec les évènements extrêmes. Pour ce qui est de l'assurance automobile, nous testons différentes méthodes pour répondre aux évolutions techniques et réglementaires. Nous caractérisons la partition homme / femme en utilisant la procédure logistique, l'analyse des correspondances multiples ou les arbres de classification. Nous montrons qu'il est possible de compenser l'absence de la variable sexe par d'autres informations spécifiques à l'assuré ou à son véhicule et en particulier l'utilisation de relevés kilométriques. Enfin, nous nous intéressons à l'expérience acquise par les conducteurs novices. Nous étudions le comportement sur la route de l'assuré pour créer de nouvelles classes de risques / In this Ph.D. Dissertation we study the storm guarantee dedicated to the damage caused by the wind and a development of the behavioral insurance through the automobile risk. We associate external information like the wind speed to insurance data. We propose the construction of a storm index to complete and strengthen the evaluation of the damages caused by the major storms. Then we define a partition of the French territory in 6 zones storms, depending on extreme wind correlations to test several scenarios. These various tests and considerations allow us to improve our storm index. We lean on extreme value theory models to show the impact of the variability on the calculation of return periods and capital requirements. We underline the difficulties to obtain strong results in connection with the extreme events. Concerning car insurance, we test various methods to answer the technical and legal evolutions. We characterize the man/woman partition by using the logistic procedure, the multiple correspondence analysis or the classification trees. We show that it is possible to compensate for the absence of the sex variable with other information specific to the insurants or to their vehicle and in particular the use of kilometric data. Finally, we are interested in the acquired experience by young drivers. We study the behavior on the road of the insurants to create new classes of risks

Page generated in 0.0457 seconds