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  • 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.
881

Étude comparative des trajectoires criminelles des contrevenants sous responsabilité provinciale au Québec, selon le sexe

Jallet, Sandrine 08 1900 (has links)
Contexte et objectifs. La carrière criminelle est un sujet d’intérêt criminologique depuis plus de 80 ans. Les travaux sur cette question ont permis de mieux comprendre l’évolution des personnes contrevenantes et leurs crimes au fil du temps. Bien que beaucoup d’efforts aient été déployés pour étudier les hommes, les recherches portant sur les trajectoires criminelles des femmes demeurent relativement rares, ceci étant notamment attribuable à la petite taille des échantillons. L’objectif de ce mémoire est de réaliser une étude comparative de la carrière criminelle d’hommes et de femmes de 18 à 47 ans relevant de la juridiction de la province de Québec. Méthodologie. L’échantillon est composé de 3320 délinquants sous responsabilité provinciale, soit 216 femmes (6,5 %) et 3104 hommes (93,5 %). Des statistiques descriptives seront réalisées afin de dresser un portrait de la clientèle et une approche par variable latente catégorielle sera utilisée pour modéliser les parcours criminels. Plus précisément, cette analyse permet d’estimer des sous-groupes de délinquants au sein de la population qui suivent des courbes de croissance distinctes. La proportion d’individus appartenant à chacun de ces sous-groupes peut donc être estimée. Résultats. Les analyses indiquent que les femmes ont une fréquence de délits commis plus faible que les hommes, et ce, particulièrement au début de leur carrière criminelle. En effet, la différence quant à la fréquence tend à s’atténuer avec le temps, pour disparaître vers 40 ans. Également, il apparaît que les hommes et les femmes suivent un nombre de trajectoires criminelles similaires; cependant, la prévalence chez ces dernières apparaît relativement différente. En effet, il ressort que les femmes commencent plus tardivement leur carrière criminelle que les hommes, avec une proportion plus importante pour les crimes contre les biens. Finalement, les antécédents juvéniles influent sur la chronicité et la persistance, quel que soit le genre ou le type de crime. Conclusion. Les résultats démontrent que la différence selon le sexe est un sujet d’intérêt criminologique primordial puisque les femmes présentent des risques différents quant à la fréquence et au type de crime. Qui plus est, ces dernières semblent commencer leur carrière criminelle plus tardivement que les hommes. / Context and objectives. Criminal careers has been a subject of interest among criminologists for over 80 years. This research has allowed a better understanding of the evolution of criminalised individuals over time. However, research focusing on the criminal careers of women are relatively rare, this being mainly attributed to the nature of the chosen sample. While overcoming the potential limitations found in previous studies, the objective of this research is to conduct a comparative study of criminal careers among men and women (as of 18 until 47 years old) under provincial jurisdiction. Method. The sample consists of 3,320 offenders under provincial jurisdiction. The sample includes 216 female participants (6.5%) and 3104 male participants (93.5%). Descriptive statistics will be presented in order to provide a detailed portrait of offenders from 18 to 47 years old. Then, the categorical latent variable approach will be used. This type of analysis provides an estimate of sub-groups of offenders within the population that follow the growth curves separately. Thus, the proportion of individuals belonging to each of these subgroups can be estimated. Results. Women have a lower incidence of crime than men especially at the beginning of a criminal career; however this difference disappears towards the age of 40. It appears that men and women, at a certain period of time have similarities in their criminal careers. However, the prevalence of criminality among women is quite different from men. Indeed, it appears that women begin their criminal careers later than men, with a higher proportion of crimes against property. The juvenile history of criminal offence influences the perseverance in criminal careers among men and women, regardless of the type of offence. Conclusion. The results demonstrate the relevance of the difference between men and women during their criminal career. It should be one of the top interests for criminologists since women have different risks leading to offenses, as well as frequency and type of offense. Moreover, they appear to begin their criminal careers later than men.
882

Observational Uncertainties in Water-Resources Modelling in Central America : Methods for Uncertainty Estimation and Model Evaluation / Observationsosäkerheter i vattenresursmodellering i Centralamerika : Metoder för osäkerhetsuppskattning och modellutvärdering

Westerberg, Ida January 2011 (has links)
Knowledge about spatial and temporal variability of hydrological processes is central for sustainable water-resources management, and such knowledge is created from observational data. Hydrologic models are necessary for prediction for time periods and areas lacking data, but are affected by observational uncertainties. Methods for estimating and accounting for such uncertainties in water-resources modelling are of high importance, especially in regions such as Central America. Observational uncertainties were addressed in three ways in this thesis; quality control, quantitative estimation and development of model-evaluation techniques that addressed unquantifiable uncertainties. A first step in any modelling study should be the quality control and concurrent analysis of the representativeness of the observational data. In the characterisation of the precipitation regime in the Choluteca River basin in Honduras, four different quality problems were identified and 22% of the daily data had to be rejected. The monitoring network was found to be insufficient for a comprehensive characterisation of the high spatiotemporal variability of the precipitation regime. Quantitative estimations of data uncertainties can be made when sufficient information is available. Discharge-data uncertainties were estimated with a fuzzy regression for time-variable rating curves and from official rating curves for 35 stations in Honduras. The uncertainties were largest for low flows, as a result of measurement uncertainties and natural variability. A method for calibration with flow-duration curves was developed which enabled calibration to the whole flow range, accounting for discharge uncertainty and calibration with non-overlapping time periods for model input and evaluation data. The method compared favourably to traditional calibration in a test using two models applied in basins with different runoff-generation processes. A post-hoc analysis made it possible to identify potential model-structure errors and periods of disinformative data. Flow-duration curves were regionalised and used for calibration of a Central-American water-balance model. The initial model uncertainty for the ungauged basins was reduced by 70%. Non-representative precipitation data were found to be the main obstacle to comprehensive regional water-resources modelling in Central America. These methods bridged several problems related to observational uncertainties in water-balance modelling. Estimates of prediction uncertainty are an important basis for all types of decisions related to water-resources management. / Kännedom om hur hydrologiska processer varierar i tid och rum är grundläggande för hållbar vattenresursförvaltning och skapas utifrån observerade data. Hydrologiska modeller är nödvändiga för att förutsäga vattenbalansen för tidsperioder och områden utan data, men påverkas av observationsosäkerheter. Metoder för att hantera sådana osäkerheter i vattenresursmodellering är av stor betydelse i regioner såsom Centralamerika. Observationsosäkerheter hanterades på tre olika sätt i denna avhandling; kvalitetskontroll, kvantitativ uppskattning och utveckling av modellutvärderingsmetoder för beaktande av icke kvantifierbara osäkerheter. Ett viktigt första steg är kvalitetskontroll och samtidig analys av datas representativitet. Vid karaktäriseringen av nederbördsregimen i Cholutecaflodens avrinningsområde i Honduras identifierades fyra olika kvalitetsproblem och 22 % av data sorterades bort. Stationsnätet var otillräckligt för en fullödig karaktärisering av nederbördsregimens variationer i tid och rum. Dessa var mycket stora som ett resultat av komplexiteten hos de nederbördsgenererande mekanismerna. Kvantitativ uppskattning av observerade datas osäkerhet kan göras när tillräcklig information är tillgänglig. Osäkerheter i vattenföringsdata uppskattades dels vid beräkning av vattenföring med en oskarp regression för en tidsvariabel avbördningskurva, dels från en analys av officiella avbördningskurvor från 35 stationer i Honduras. Osäkerheten var i båda fallen högst vid låga flöden som ett resultat av högre mätosäkerheter samt större naturlig variabilitet än vid höga flöden. En metod för modellkalibrering med varaktighetskurvor utvecklades och gjorde det möjligt att kalibrera för hela flödesintervallet samtidigt, ta hänsyn till osäkerheter i vattenföringsdata samt kalibrera med icke överlappande driv- och utvärderingsdata. Metoden testades med två olika modeller i två avrinningsområden med olika avrinningsbildningsprocesser, och visade goda resultat jämfört med traditionell modellkalibrering. En post hoc-analys gjorde det möjligt att identifiera troliga modellstrukturfel och perioder med disinformativa data. Varaktighetskurvor regionaliserades och användes för kalibrering av en regional vattenbalansmodell för Centralamerika, varvid den initiala modellosäkerheten minskades med 70 %. Icke representativa nederbördsdata identifierades som det största hindret för regional vattenresursmodellering i Centralamerika. De metoder som utvecklades i detta arbete gör det möjligt att överbrygga ett flertal problem orsakade av bristfällig tillgänglighet och kvalitet av data och leder därmed till en förbättrad uppskattning av osäkerheten i vattenbalanssimuleringar. Sådana osäkerhetsskattningar är ett viktigt underlag vid alla typer av förvaltningsbeslut som rör vattenresurser.
883

Economic consequences of motherhood - the role of job disamenities

Felfe, Andrea Christina 15 July 2008 (has links)
Esta tesis evalúa el papel de las características no deseadas del trabajo - llamadas disamenities - en el contexto del balance entre trabajo y familia. Particularmente, se plantean las siguientes preguntas: ¿es el descenso en el salario de las mujeres luego del nacimiento del primer hijo - llamado child penalty - acompañado por una reducción simultánea en las disamenities?; ¿cuánto salario están dispuestas las madres a sacrificar para reducir las disamenities?; ¿las disamenities propias del trabajo de las madres tienen algún efecto sobre el desarrollo cognitivo de sus hijos? En el capitulo I se describe empíricamente como las características del trabajo de las madres cambian luego del nacimiento del primer hijo y se testea la hipótesis de que si el child penalty se puede explicar como un diferencial salarial compensatorio. En el capitulo II se estima la disposición marginal a pagar de las madres para reducir las disamenities. La estrategia de identificación está basada en la baja por maternidad, la cual constituye un contexto que permite modelar más cabalmente la decisión sobre la participación laboral; y por consiguiente, mejora la metodología existente para estimar la disposición marginal a pagar por parte de las madres. Finalmente, en el capitulo III se investiga el impacto de las disamenities del trabajo de las madres sobre el desarrollo infantil. / This dissertation evaluates the role of job disamenities - job characteristics disliked by workers - in the context of work-family balance. In particular, the following questions are raised. Is the decrease in mothers' wages around first childbirth - the so-called child penalty - accompanied by a simultaneous reduction in job disamenities? How much wage are mothers willing to sacrifice in order to reduce job disamenities? Do disamenities involved in mothers' occupations go on to affect parenting behaviour and as a result harm children's cognitive development? Chapter I provides empirical evidence for changes in maternal working conditions around first childbirth and tests the hypothesis if the child penalty can be explained by a compensating wage differential? Chapter II estimates mothers' marginal willingness to pay to reduce job disamenities. The identification strategy relies on the framework of maternal leave, a setting which allows us to model mothers' decision to join the labor force accurately and hence to improve on the existing methodology to estimate the marginal willingness to pay. Chapter III investigates how disamenities involved in mothers' occupation go on to affect children's cognitive outcomes.
884

A morada como duração da memória : estudo antropológico das narrativas e trajetórias sociais de núcleos familiares e redes de camadas médias urbanas habitantes da cidade de Porto Alegre, RS - Brasil e do bairro de San Telmo, na cidade de Buenos Aires - Argentina

Gutterres, Anelise dos Santos January 2010 (has links)
Essa dissertação aborda o tema dos ritmos temporais nas cidades modernocontemporâneas a partir da experiência etnográfica entre núcleos familiares e redes de camadas médias urbanas. Inserida nas discussões sobre planejamento urbano, construção e destruição de propriedade privada residencial, abordamos as representações da morada a partir das imagens que a compõem. O estudo busca pensar o espaço da morada como objeto do tempo nos bairros: Tristeza, Rio Branco, Floresta e Petrópolis, na cidade de Porto Alegre, Brasil; e o Bairro de San Telmo, na cidade de Buenos Aires, Argentina. A partir da pesquisa em imagens de acervo e dados oriundos do método etnográfico buscamos pensar a transformação da cidade a partir das narrativas biográficas e das trajetórias sociais dos integrantes desses diferentes contextos etnográficos por intermédio da noção de memória e de uma etnografia da duração. / This thesis intends to establish how the representation of “morada”, in moderncontemporary cities, from the perspective of an ethnographic experience affects the family groups and networks of urban middle classes. The thesis discusses urban planning, construction and destruction of private residential properties, specially including several visual representations of the “morada”. It aims to ponder the “morada” space, as an object changing in a time, in the neighborhoods of Tristeza, Rio Branco, Floresta and Petrópolis, all in the city of Porto Alegre, Brazil, and San Telmo, in Buenos Aires, Argentina. Searching the data and image collection gathered in an ethnographic method, the thesis discusses the transformation the cities go through, from the perspective of the biographic narratives and social trajectories of the members of those different ethnographic contexts, from the perspective of memory and ethnographic duration. / Esta tesis abarca la cuestion de las ritmos temporales en las ciudades modernocontemporaneas, desde la experiencia etnográfica entre los grupos familiares y las redes de clase media urbana. Incluidos en las discusiones acerca de la planificación urbana, la construcción y la destrucción de la propiedad residencial privada, hablamos de las representaciones de la “morada” desde las imágenes que componen. El estudio tiene como objetivo reflexionar sobre el espacio de la “morada” como un objeto de tiempo en los barrios: Tristeza, Rio Branco, Floresta y Petrópolis, la ciudad de Porto Alegre en Brasil, y San Telmo, en Buenos Aires, Argentina. Desde la investigación cerca de las colecciones de imágenes de museos y arquivos e incluso datos de la etnografía reflexionamos sobre la transformación de la ciudad desde las narrativas y trayectorias sociales de los miembros de los diferentes contextos etnográficos utilizando el concepto de la memoria y la etnografía de la duracion.
885

Decisão monocrática e agravo interno: lesão ao devido processo legal?

Almeida Filho, Agostinho Teixeira de January 2010 (has links)
Submitted by Pedro Mizukami (pedro.mizukami@fgv.br) on 2011-08-17T20:57:51Z No. of bitstreams: 1 DMPPJ - AGOSTINHO TEIXEIRA DE ALMEIDA FILHO.pdf: 589195 bytes, checksum: 1790025fb2fdaf4044dbb92314c6c229 (MD5) / Approved for entry into archive by Pedro Mizukami (pedro.mizukami@fgv.br) on 2011-08-19T17:44:43Z (GMT) No. of bitstreams: 1 DMPPJ - AGOSTINHO TEIXEIRA DE ALMEIDA FILHO.pdf: 589195 bytes, checksum: 1790025fb2fdaf4044dbb92314c6c229 (MD5) / Made available in DSpace on 2011-09-02T18:44:10Z (GMT). No. of bitstreams: 1 DMPPJ - AGOSTINHO TEIXEIRA DE ALMEIDA FILHO.pdf: 589195 bytes, checksum: 1790025fb2fdaf4044dbb92314c6c229 (MD5) Previous issue date: 2010 / Esta dissertação tem por objetivo analisar os institutos da decisão monocrática e do agravo interno, sob o prisma de metodologia empírica que busca priorizar a realidade pragmática da aplicação do artigo 557 do Código de Processo Civil. Enfocou-se o instituto da decisão monocrática no contexto das minirreformas processuais brasileiras, que tiveram como alicerce o princípio da efetividade processual. Esse princípio pressupõe a duração razoável do processo, garantida na Constituição Federal Brasileira. A partir da constitucionalidade desse princípio, defendeu-se a constitucionalidade do artigo 557 do Código de Processo Civil, que não pode ser considerado abstratamente inconstitucional. Demonstrou-se que a aplicabilidade do artigo 557 pode ser inconstitucional se não atender à técnica da ponderação de valores, que garante a interpretação conforme a Constituição. Analisou-se o agravo interno, sob a premissa do valor da celeridade em cotejo com o devido processo legal, que permeou a subsequente análise do procedimento desta espécie de agravo. Após uma reflexão sobre os institutos da decisão monocrática e do agravo interno, aliada ao exame dos princípios do devido processo legal, ampla defesa, contraditório e motivação das decisões judiciais, passou-se ao exame empírico desses institutos jurídicos. Nessa análise, foram coletados e examinados dados estatísticos, que confirmaram – e, assim, possibilitaram a conclusão da dissertação – a constitucionalidade do artigo 557 e a importância de sua interpretação conforme os referidos princípios constitucionais. / This dissertation has the purpose to analise the institutes of the single verdict and the internal appeal, according to empirical methodology that focus the pragmatic reality of the 557 th. dispositive of Code of Civil Procedure`s enforcement. This dissertation focused the institute of the single verdict in the context of the reformation of the Brazilian Code of Civil Procedure, which had as foundation the principle of procedure efectiveness. This principle presupposes a reasonable duration of the suit, secured by the Brazilian Federal Constitution. From the constitutionality of this principal, this dissertation defended the constitutionality of the 557 th. dispositive of Code of Civil Procedure, which can`t be considered abstractedly unconstitutional. This dissertation proved that the enforcement of the 557 th. dispositive could be unconstitutional if doesn`t suit the technique of the weighing of values, which secures the interpretation according to the Brazilian Federal Constitution. This dissertation analised the internal appeal, under the presupposition of the value of the reasonable duration of the suit in comparison with the due process of law, which motivate the following analysis of the internal appeal proceeding. After a reflection of single verdict and the internal appeal institutes, also with the analysis of due process of law, legal defense, adversary system and the motivation of the judgement, this dissertation analised the empirical enforcement of these institutes. In this analysis, estatistic data have been collected, which corroborate – and, therefore, enabled the conclusion of the dissertation – the constitutionality of the 557 th. dispositive of Code of Civil Procedure and the consideration of its interpretation according to the mentioned constitucional principles.
886

A morada como duração da memória : estudo antropológico das narrativas e trajetórias sociais de núcleos familiares e redes de camadas médias urbanas habitantes da cidade de Porto Alegre, RS - Brasil e do bairro de San Telmo, na cidade de Buenos Aires - Argentina

Gutterres, Anelise dos Santos January 2010 (has links)
Essa dissertação aborda o tema dos ritmos temporais nas cidades modernocontemporâneas a partir da experiência etnográfica entre núcleos familiares e redes de camadas médias urbanas. Inserida nas discussões sobre planejamento urbano, construção e destruição de propriedade privada residencial, abordamos as representações da morada a partir das imagens que a compõem. O estudo busca pensar o espaço da morada como objeto do tempo nos bairros: Tristeza, Rio Branco, Floresta e Petrópolis, na cidade de Porto Alegre, Brasil; e o Bairro de San Telmo, na cidade de Buenos Aires, Argentina. A partir da pesquisa em imagens de acervo e dados oriundos do método etnográfico buscamos pensar a transformação da cidade a partir das narrativas biográficas e das trajetórias sociais dos integrantes desses diferentes contextos etnográficos por intermédio da noção de memória e de uma etnografia da duração. / This thesis intends to establish how the representation of “morada”, in moderncontemporary cities, from the perspective of an ethnographic experience affects the family groups and networks of urban middle classes. The thesis discusses urban planning, construction and destruction of private residential properties, specially including several visual representations of the “morada”. It aims to ponder the “morada” space, as an object changing in a time, in the neighborhoods of Tristeza, Rio Branco, Floresta and Petrópolis, all in the city of Porto Alegre, Brazil, and San Telmo, in Buenos Aires, Argentina. Searching the data and image collection gathered in an ethnographic method, the thesis discusses the transformation the cities go through, from the perspective of the biographic narratives and social trajectories of the members of those different ethnographic contexts, from the perspective of memory and ethnographic duration. / Esta tesis abarca la cuestion de las ritmos temporales en las ciudades modernocontemporaneas, desde la experiencia etnográfica entre los grupos familiares y las redes de clase media urbana. Incluidos en las discusiones acerca de la planificación urbana, la construcción y la destrucción de la propiedad residencial privada, hablamos de las representaciones de la “morada” desde las imágenes que componen. El estudio tiene como objetivo reflexionar sobre el espacio de la “morada” como un objeto de tiempo en los barrios: Tristeza, Rio Branco, Floresta y Petrópolis, la ciudad de Porto Alegre en Brasil, y San Telmo, en Buenos Aires, Argentina. Desde la investigación cerca de las colecciones de imágenes de museos y arquivos e incluso datos de la etnografía reflexionamos sobre la transformación de la ciudad desde las narrativas y trayectorias sociales de los miembros de los diferentes contextos etnográficos utilizando el concepto de la memoria y la etnografía de la duracion.
887

A morada como duração da memória : estudo antropológico das narrativas e trajetórias sociais de núcleos familiares e redes de camadas médias urbanas habitantes da cidade de Porto Alegre, RS - Brasil e do bairro de San Telmo, na cidade de Buenos Aires - Argentina

Gutterres, Anelise dos Santos January 2010 (has links)
Essa dissertação aborda o tema dos ritmos temporais nas cidades modernocontemporâneas a partir da experiência etnográfica entre núcleos familiares e redes de camadas médias urbanas. Inserida nas discussões sobre planejamento urbano, construção e destruição de propriedade privada residencial, abordamos as representações da morada a partir das imagens que a compõem. O estudo busca pensar o espaço da morada como objeto do tempo nos bairros: Tristeza, Rio Branco, Floresta e Petrópolis, na cidade de Porto Alegre, Brasil; e o Bairro de San Telmo, na cidade de Buenos Aires, Argentina. A partir da pesquisa em imagens de acervo e dados oriundos do método etnográfico buscamos pensar a transformação da cidade a partir das narrativas biográficas e das trajetórias sociais dos integrantes desses diferentes contextos etnográficos por intermédio da noção de memória e de uma etnografia da duração. / This thesis intends to establish how the representation of “morada”, in moderncontemporary cities, from the perspective of an ethnographic experience affects the family groups and networks of urban middle classes. The thesis discusses urban planning, construction and destruction of private residential properties, specially including several visual representations of the “morada”. It aims to ponder the “morada” space, as an object changing in a time, in the neighborhoods of Tristeza, Rio Branco, Floresta and Petrópolis, all in the city of Porto Alegre, Brazil, and San Telmo, in Buenos Aires, Argentina. Searching the data and image collection gathered in an ethnographic method, the thesis discusses the transformation the cities go through, from the perspective of the biographic narratives and social trajectories of the members of those different ethnographic contexts, from the perspective of memory and ethnographic duration. / Esta tesis abarca la cuestion de las ritmos temporales en las ciudades modernocontemporaneas, desde la experiencia etnográfica entre los grupos familiares y las redes de clase media urbana. Incluidos en las discusiones acerca de la planificación urbana, la construcción y la destrucción de la propiedad residencial privada, hablamos de las representaciones de la “morada” desde las imágenes que componen. El estudio tiene como objetivo reflexionar sobre el espacio de la “morada” como un objeto de tiempo en los barrios: Tristeza, Rio Branco, Floresta y Petrópolis, la ciudad de Porto Alegre en Brasil, y San Telmo, en Buenos Aires, Argentina. Desde la investigación cerca de las colecciones de imágenes de museos y arquivos e incluso datos de la etnografía reflexionamos sobre la transformación de la ciudad desde las narrativas y trayectorias sociales de los miembros de los diferentes contextos etnográficos utilizando el concepto de la memoria y la etnografía de la duracion.
888

Uncertainty Analysis of Microwave Based Rainfall Estimates over a River Basin Using TRMM Orbital Data Products

Indu, J January 2014 (has links) (PDF)
Error characteristics associated with satellite-derived precipitation products are important for atmospheric and hydrological model data assimilation, forecasting, and climate diagnostic applications. This information also aids in the refinement of physical assumptions within algorithms by identifying geographical regions and seasons where existing algorithm physics may be incorrect or incomplete. Examination of relative errors between independent estimates derived from satellite microwave data is particularly important over regions with limited surface-based equipments for measuring rain rate such as the global oceans and tropical continents. In this context, analysis of microwave based satellite datasets from the Tropical Rainfall Measuring Mission (TRMM) enables to not only provide information regarding the inherent uncertainty within the current TRMM products, but also serves as an opportunity to prototype error characterization methodologies for the TRMM follow-on program, the Global Precipitation Measurement (GPM) . Most of the TRMM uncertainty evaluation studies focus on the accuracy of rainfall accumulated over time (e.g., season/year). Evaluation of instantaneous rainfall intensities from TRMM orbital data products is relatively rare. These instantaneous products are known to potentially cause large uncertainties during real time flood forecasting studies at the watershed scale. This is more so over land regions, where the highly varying land surface emissivity offers a myriad of complications, hindering accurate rainfall estimation. The error components of orbital data products also tend to interact nonlinearly with hydrologic modeling uncertainty. Keeping these in mind, the present thesis fosters the development of uncertainty analysis using instantaneous satellite orbital data products (latest version 7 of 1B11, 2A25, 2A23, 2B31, 2A12) derived from the passive and active microwave sensors onboard TRMM satellite, namely TRMM Microwave Imager (TMI) and precipitation radar (PR). The study utilizes 11 years of orbital data from 2002 to 2012 over the Indian subcontinent and examines the influence of various error sources on the convective and stratiform precipitation types. Two approaches are taken up to examine uncertainty. While the first approach analyses independent contribution of error from these orbital data products, the second approach examines their combined effect. Based on the first approach, analysis conducted over the land regions of Mahanadi basin, India investigates three sources of uncertainty in detail. These include 1) errors due to improper delineation of rainfall signature within microwave footprint (rain/no rain classification), 2) uncertainty offered by the transfer function linking rainfall with TMI low frequency channels and 3) sampling errors owing to the narrow swath and infrequent visits of TRMM sensors. The second approach is hinged on evaluating the performance of rainfall estimates from each of these orbital data products by accumulating them within a spatial domain and using error decomposition methodologies. Microwave radiometers have taken unprecedented satellite images of earth’s weather, proving to be a valuable tool for quantitative estimation of precipitation from space. However, as mentioned earlier, with the widespread acceptance of microwave based precipitation products, it has also been recognized that they contain large uncertainties. One such source of uncertainty is contributed by improper detection of rainfall signature within radiometer footprints. To date, the most-advanced passive microwave retrieval algorithms make use of databases constructed by cloud or numerical weather model simulations that associate calculated microwave brightness temperature to physically plausible sample rain events. Delineation of rainfall signature from microwave footprints, also known as rain/norain classification (RNC) is an essential step without which the succeeding retrieval technique (using the database) gets corrupted easily. Although tremendous advances have been made to catapult RNC algorithms from simple empirical relations formulated for computational expedience to elaborate computer intensive schemes which effectively discriminate rainfall, a number of challenges remain to be addressed. Most of the algorithms that are globally developed for land, ocean and coastal regions may not perform well for regional catchments of small areal extent. Motivated by this fact, the present work develops a regional rainfall detection algorithm based on scattering index methodology for the land regions of study area. Performance evaluation of this algorithm, developed using low frequency channels (of 19 GHz, 22 GHz), are statistically tested for individual case study events during 2011 and 2012 Indian summer monsoonal months. Contingency table statistics and performance diagram show superior performance of the algorithm for land regions of the study region with accurate rain detection observed in 95% of the case studies. However, an important limitation of this approach is comparatively poor detection of low intensity stratiform rainfall. The second source of uncertainty which is addressed by the present thesis, involves prediction of overland rainfall using TMI low frequency channels. Land, being a radiometrically warm and highly variable background, offers a myriad of complications for overland rain retrieval using microwave radiometer (like TMI). Hence, land rainfall algorithms of TRMM TMI have traditionally incorporated empirical relations of microwave brightness temperature (Tb) with rain rate, rather than relying on physically based radiative transfer modeling of rainfall (as implemented in TMI ocean algorithm). In the present study, sensitivity analysis is conducted using spearman rank correlation coefficient as the indicator, to estimate the best combination of TMI low frequency channels that are highly sensitive to near surface rainfall rate (NSR) from PR. Results indicate that, the TMI channel combinations not only contain information about rainfall wherein liquid water drops are the dominant hydrometeors, but also aids in surface noise reduction over a predominantly vegetative land surface background. Further, the variations of rainfall signature in these channel combinations were seldom assessed properly due to their inherent uncertainties and highly non linear relationship with rainfall. Copula theory is a powerful tool to characterize dependency between complex hydrological variables as well as aid in uncertainty modeling by ensemble generation. Hence, this work proposes a regional model using Archimedean copulas, to study dependency of TMI channel combinations with respect to precipitation, over the land regions of Mahanadi basin, India, using version 7 orbital data from TMI and PR. Studies conducted for different rainfall regimes over the study area show suitability of Clayton and Gumbel copula for modeling convective and stratiform rainfall types for majority of the intraseasonal months. Further, large ensembles of TMI Tb (from the highly sensitive TMI channel combination) were generated conditional on various quantiles (25th, 50th, 75th, 95th) of both convective and stratiform rainfall types. Comparatively greater ambiguity was observed in modeling extreme values of convective rain type. Finally, the efficiency of the proposed model was tested by comparing the results with traditionally employed linear and quadratic models. Results reveal superior performance of the proposed copula based technique. Another persistent source of uncertainty inherent in low earth orbiting satellites like TRMM arise due to sampling errors of non negligible proportions owing to the narrow swath of satellite sensors coupled with a lack of continuous coverage due to infrequent satellite visits. This study investigates sampling uncertainty of seasonal rainfall estimates from PR, based on 11 years of PR 2A25 data product over the Indian subcontinent. A statistical bootstrap technique is employed to estimate the relative sampling errors using the PR data themselves. Results verify power law scaling characteristics of relative sampling errors with respect to space time scale of measurement. Sampling uncertainty estimates for mean seasonal rainfall was found to exhibit seasonal variations. To give a practical demonstration of the implications of bootstrap technique, PR relative sampling errors over the sub tropical river basin of Mahanadi, India were examined. Results revealed that bootstrap technique incurred relative sampling errors of <30% (for 20 grid), <35% (for 10 grid), <40% (for 0.50 grid) and <50% (for 0.250 grid). With respect to rainfall type, overall sampling uncertainty was found to be dominated by sampling uncertainty due to stratiform rainfall over the basin. In order to study the effect of sampling type on relative sampling uncertainty, the study compares the resulting error estimates with those obtained from latin hypercube sampling. Based on this study, it may be concluded that bootstrap approach can be successfully used for ascertaining relative sampling errors offered by TRMM-like satellites over gauged or ungauged basins lacking in in-situ validation data. One of the important goals of TRMM Ground Validation Program has been to estimate the random and systematic uncertainty associated with TRMM rainfall estimates. Disentangling uncertainty in seasonal rainfall offered by independent observations of TMI and PR enables to identify errors and inconsistencies in the measurements by these instruments. Motivated by this thought, the present work examines the spatial error structure of daily precipitation derived from the version 7 TRMM instantaneous orbital data products through comparison with the APHRODITE data over a subtropical region namely Mahanadi river basin of the Indian subcontinent for the seasonal rainfall of 6 years from June 2002 to September 2007. The instantaneous products examined include TMI and PR data products of 2A12, 2A25 and 2B31 (combined data from PR and TMI). The spatial distribution of uncertainty from these data products was quantified based on the performance metrics derived from the contingency table. For the seasonal daily precipitation over 10x10 grids, the data product of 2A12 showed greater skill in detecting and quantifying the volume of rainfall when compared with 2A25 and 2B31 data products. Error characterization using various error models revealed that random errors from multiplicative error models were homoscedastic and that they better represented rainfall estimates from 2A12 algorithm. Error decomposition technique, performed to disentangle systematic and random errors, testified that the multiplicative error model representing rainfall from 2A12 algorithm, successfully estimated a greater percentage of systematic error than 2A25 or 2B31 algorithms. Results indicate that even though the radiometer derived 2A12 is known to suffer from many sources of uncertainties, spatial and temporal analysis over the case study region testifies that the 2A12 rainfall estimates are in a very good agreement with the reference estimates for the data period considered. These findings clearly document that proper characterization of error structure offered by TMI and PR has wider implications in decision making, prior to incorporating the resulting orbital products for basin scale hydrologic modeling. The current missions of GPM envision a constellation of microwave sensors that can provide instantaneous products with a relatively negligible sampling error at daily or higher time scales. This study due to its simplicity and physical approach offers the ideal basis for future improvements in uncertainty modeling in precipitation.
889

Impacts of Climate Change on IDF Relationships for Design of Urban Stormwater Systems

Saha, Ujjwal January 2014 (has links) (PDF)
Increasing global mean temperature or global warming has the potential to affect the hydrologic cycle. In the 21st century, according to the UN Intergovernmental Panel on Climate Change (IPCC), alterations in the frequency and magnitude of high intensity rainfall events are very likely. Increasing trend of urbanization across the globe is also noticeable, simultaneously. These changes will have a great impact on water infrastructure as well as environment in urban areas. One of the impacts may be the increase in frequency and extent of flooding. India, in the recent years, has witnessed a number of urban floods that have resulted in huge economic losses, an instance being the flooding of Mumbai in July, 2005. To prevent catastrophic damages due to floods, it has become increasingly important to understand the likely changes in extreme rainfall in future, its effect on the urban drainage system, and the measures that can be taken to prevent or reduce the damage due to floods. Reliable estimation of future design rainfall intensity accounting for uncertainties due to climate change is an important research issue. In this context, rainfall intensity-duration-frequency (IDF) relationships are one of the most extensively used hydrologic tools in planning, design and operation of various drainage related infrastructures in urban areas. There is, thus, a need for a study that investigates the potential effects of climate change on IDF relationships. The main aim of the research reported in this thesis is to investigate the effect of climate change on Intensity-Duration-Frequency relationship in an urban area. The rainfall in Bangalore City is used as a case study to demonstrate the applications of the methodologies developed in the research Ahead of studying the future changes, it is essential to investigate the signature of changes in the observed hydrological and climatological data series. Initially, the yearly mean temperature records are studied to find out the signature of global warming. It is observed that the temperature of Bangalore City shows an evidence of warming trend at a statistical confidence level of 99.9 %, and that warming effect is visible in terms of increase of minimum temperature at a rate higher than that of maximum temperature. Interdependence studies between temperature and extreme rainfall reveal that up to a certain range, increase in temperature intensifies short term rainfall intensities at a rate more than the average rainfall. From these two findings, it is clear that short duration rainfall intensities may intensify in the future due to global warming and urban heat island effect. The possible urbanization signatures in the extreme rainfall in terms of intensification in the evening and weekends are also inferred, although inconclusively. The IDF relationships are developed with historical data and changes in the long term daily rainfall extreme characteristics are studied. Multidecedal oscillations in the daily rainfall extreme series are also examined. Further, non-parametric trend analyses of various indices of extreme rainfall are carried out to confirm that there is a trend of increase in extreme rainfall amount and frequency, and therefore it is essential to the study the effects of climate change on the IDF relationships of the Bangalore City. Estimation of future changes in rainfall at hydrological scale generally relies on simulations of future climate provided by Global Climate Models (GCMs). Due to spatial and temporal resolution mismatch, GCM results need to be downscaled to get the information at station scale and at time resolutions necessary in the context of urban flooding. The downscaling of extreme rainfall characteristics in an urban station scale pose the following challenges: (1) downscaling methodology should be efficient enough to simulate rainfall at the tail of rainfall distribution (e.g., annual maximum rainfall), (2) downscaling at hourly or up to a few minutes temporal resolution is required, and (3) various uncertainties such as GCM uncertainties, future scenario uncertainties and uncertainties due to various statistical methodologies need to be addressed. For overcoming the first challenge, a stochastic rainfall generator is developed for spatial downscaling of GCM precipitation flux information to station scale to get the daily annual maximum rainfall series (AMRS). Although Regional Climate Models (RCMs) are meant to simulate precipitation at regional scales, they fail to simulate extreme events accurately. Transfer function based methods and weather typing techniques are also generally inefficient in simulating the extreme events. Due to its stochastic nature, rainfall generator is better suited for extreme event generation. An algorithm for stochastic simulation of rainfall, which simulates both the mean and extreme rainfall satisfactorily, is developed in the thesis and used for future projection of rainfall by perturbing the parameters of the rainfall generator for the future time periods. In this study, instead of using the customary two states (rain/dry) Markov chain, a three state hybrid Markov chain is developed. The three states used in the Markov chain are: dry day, moderate rain day and heavy rain day. The model first decides whether a day is dry or rainy, like the traditional weather generator (WGEN) using two transition probabilities, probabilities of a rain day following a dry day (P01), and a rain day following a rain day (P11). Then, the state of a rain day is further classified as a moderate rain day or a heavy rain day. For this purpose, rainfall above 90th percentile value of the non-zero precipitation distribution is termed as a heavy rain day. The state of a day is assigned based on transition probabilities (probabilities of a rain day following a dry day (P01), and a rain day following a rain day (P11)) and a uniform random number. The rainfall amount is generated by Monte Carlo method for the moderate and heavy rain days separately. Two different gamma distributions are fitted for the moderate and heavy rain days. Segregating the rain days into two different classes improves the process of generation of extreme rainfall. For overcoming the second challenge, i.e. requirement of temporal scales, the daily scale IDF ordinates are disaggregated into hourly and sub-hourly durations. Disaggregating continuous rainfall time series at sub-hourly scale requires continuous rainfall data at a fine scale (15 minute), which is not available for most of the Indian rain gauge stations. Hence, scale invariance properties of extreme rainfall time series over various rainfall durations are investigated through scaling behavior of the non-central moments (NCMs) of generalized extreme value (GEV) distribution. The scale invariance properties of extreme rainfall time series are then used to disaggregate the distributional properties of daily rainfall to hourly and sub-hourly scale. Assuming the scaling relationships as stationary, future sub-hourly and hourly IDF relationships are developed. Uncertainties associated with the climate change impacts arise due to existence of several GCMs developed by different institutes across the globe, climate simulations available for different representative concentration pathway (RCP) scenarios, and the diverse statistical techniques available for downscaling. Downscaled output from a single GCM with a single emission scenario represents only a single trajectory of all possible future climate realizations and cannot be representative of the full extent of climate change. Therefore, a comprehensive assessment of future projections should use the collective information from an ensemble of GCM simulations. In this study, 26 different GCMs and 4 RCP scenarios are taken into account to come up with a range of IDF curves at different future time periods. Reliability ensemble averaging (REA) method is used for obtaining weighted average from the ensemble of projections. Scenario uncertainty is not addressed in this study. Two different downscaling techniques (viz., delta change and stochastic rainfall generator) are used to assess the uncertainty due to downscaling techniques. From the results, it can be concluded that the delta change method under-estimated the extreme rainfall compared to the rainfall generator approach. This study also confirms that the delta change method is not suitable for impact studies related to changes in extreme events, similar to some earlier studies. Thus, mean IDF relationships for three different future extreme events, similar to some earlier studies. Thus, mean IDF relationships for three different future periods and four RCP scenarios are simulated using rainfall generator, scaling GEV method, and REA method. The results suggest that the shorter duration rainfall will invigorate more due to climate change. The change is likely to be in the range of 20% to 80%, in the rainfall intensities across all durations. Finally, future projected rainfall intensities are used to investigate the possible impact of climate change in the existing drainage system of the Challaghatta valley in the Bangalore City by running the Storm Water Management Model (SWMM) for historical period, and the best and the worst case scenario for three future time period of 2021–2050, 2051–2080 and 2071–2100. The results indicate that the existing drainage is inadequate for current condition as well as for future scenarios. The number of nodes flooded will increase as the time period increases, and a huge change in runoff volume is projected. The modifications of the drainage system are suggested by providing storage pond for storing the excess high speed runoff in order to restrict the width of the drain The main research contribution of this thesis thus comes from an analysis of trends of extreme rainfall in an urban area followed by projecting changes in the IDF relationships under climate change scenarios and quantifying uncertainties in the projections.
890

Spécificités de l'implant électro-acoustique : indications, interface bioélectrique et stratégie de codage / Specificities of electric-acoustic stimulation : indications, bioelectrical interface and coding strategy

Seldran, Fabien 19 December 2011 (has links)
Le clinicien se trouve parfois confronté à des sujets qui présentent une surdité supérieure à 90 dB HL au-delà de 1 kHz avec une audition résiduelle dans les fréquences graves. Pour réhabiliter les hautes fréquences, il existe aujourd’hui différentes technologies : amplification conventionnelle, compression fréquentielle, implant cochléaire et depuis une dizaine d’année la stimulation électro-acoustique EAS qui consiste à stimuler acoustiquement les sons graves et électriquement les sons aigus via un implant cochléaire. La première partie de cette thèse a consisté à identifier les facteurs qui influencent les capacités des patients sourds partiels à traiter l’information basse fréquence de la parole. Nous avons utilisé un test d’audiométrie vocale filtrée passe-bas. Nos résultats indiquent que les scores d’intelligibilité de la parole sont positivement corrélés avec la durée de la surdité. Ceci signifie qu’avec le temps, ces sujets malentendants apprennent à comprendre avec cette audition type filtre passe-bas, à tel point que certains ont des performances supra-normales pour l’utilisation des basses fréquences. Nos résultats montrent également une corrélation négative entre l’âge d’apparition de la surdité et les scores l’intelligibilité. Ce test pourra aider le clinicien à mieux cibler l’appareillage le plus adapté à chaque profil de patient. La seconde partie de cette thèse, consacrée à l’EAS, a consisté à évaluer par des simulations chez le normo-entendant, diverses stratégies de codage du son par l’implant EAS. Actuellement, la stratégie utilisée pour l’EAS est calquée sur celle de l’implant cochléaire et nos résultats suggèrent que cette stratégie peut être optimisée. / Clinicians may face patients who have a deafness superior to 90 dB HL above 1 kHz with good lowfrequency residual hearing. Today, several technologies are available to provide high frequencies: conventional amplification, frequency compression, cochlear implant since about 10 years Electric-Acoustic Stimulation EAS which consists in stimulating acoustically low frequencies while stimulating electrically high frequency sounds via a cochlear implant. The firt part of this dissertation consisted in identifying the factors which may influence abilities of partially deaf subjects to process low-frequency speech information. We used a low-pass filtered speech test. Our results show that speech intelligibility scores are positively correlated to the duration of deafness. This means that these hearing-impaired subjects learn to understand with this lowpass-like hearing, in such a way that some of them exhibit supranormal abilities for the processing of low-frequency sounds. Our results also show a negative correlation between the age at onset of deafness and speech intelligibility scores. This test may help the clinician to better evaluate which device would be best for every patient’s profile. The second part of this dissertation, about EAS, consisted in evaluating through simulations in normal hearing listeners, several coding strategies by the EAS implant. Now the strategy used for EAS duplicates the strategy used by cochlear implants and our results suggest that this strategy could be optimized.

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