Siga este link para ver outros tipos de publicações sobre o tema: IDF curves.
Teses / dissertações sobre o tema "IDF curves"
Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos
Veja os 50 melhores trabalhos (teses / dissertações) para estudos sobre o assunto "IDF curves".
Ao lado de cada fonte na lista de referências, há um botão "Adicionar à bibliografia". Clique e geraremos automaticamente a citação bibliográfica do trabalho escolhido no estilo de citação de que você precisa: APA, MLA, Harvard, Chicago, Vancouver, etc.
Você também pode baixar o texto completo da publicação científica em formato .pdf e ler o resumo do trabalho online se estiver presente nos metadados.
Veja as teses / dissertações das mais diversas áreas científicas e compile uma bibliografia correta.
1
Castillo, Jean M. "Duration-rainfall intensity equations : study of IDF curves using local precipitation data /". Available to subscribers only, 2006. http://proquest.umi.com/pqdweb?did=1203570521&sid=23&Fmt=2&clientId=1509&RQT=309&VName=PQD.
Texto completo da fonte
2
Haruna, Abubakar. "Améliorer l'estimation des aléas de précipitations grâce aux relations Intensité-Durée-Aire-Fréquence (IDAF). Application à une zone à la topographie complexe". Electronic Thesis or Diss., Université Grenoble Alpes, 2024. http://www.theses.fr/2024GRALU002.
Texto completo da fonteResumo:
À une époque impactée par des phénomènes météorologiques de plus en plus variables qui peuvent modifier profondément les communautés, l'importance de prédictions fiables des précipitations extrêmes à de multiples échelles n'a jamais été aussi prédominante. Malgré sa portée cruciale, une prédiction précise demeure un défi de taille, en particulier dans les régions montagneuses, qui sont particulièrement exposées aux risques associés aux précipitations extrêmes. Par conséquent, des outils plus robustes sont nécessaires pour une prédiction fiable.Les relations Intensité-Durée-Aire-Fréquence (IDAF) résument les principales caractéristiques statistiques des précipitations extrêmes. Elles sont utilisées pour la quantification des aléas de précipitations et le développement de systèmes d'alerte précoce. Alors que les relations Intensité-Durée-Fréquence (IDF) pour les précipitations ponctuelles ont été largement étudiées, les relations IDAF, prenant en compte la zone d'accumulation, ont reçu beaucoup moins d'attention et, à notre connaissance, seulement pour les extrêmes.Cette thèse vise à modéliser les relations IDAF des précipitations pour toute la gamme des précipitations non nulles dans des zones à la topographie complexe (avec application en Suisse), où des modèles robustes et flexibles sont nécessaires en raison de la forte variabilité spatio-temporelle des précipitations. La grande originalité de cette thèse est que les relations IDAF sont développées pour toute la gamme des intensités de précipitations non nulles, et pas seulement pour les extrêmes. Les distributions marginales robustes des relations modélisées peuvent être utilisées dans les générateurs stochastiques de précipitation.Premièrement, nous avons identifié un modèle parcimonieux au sein de la famille extended generalized Pareto (EGPD) pour modéliser la distribution des intensités non nulles. Deuxièmement, nous avons développé trois modèles de régionalisation pour améliorer la robustesse et la fiabilité des estimations quotidiennes des précipitations. Les résultats montrent que toutes les méthodes régionales offrent une robustesse et une fiabilité accrues en matière de prédiction par rapport au modèle local (sans régionalisation). La méthode spatiale basée sur des modèles additifs généralisés (GAM) a démontré de meilleurs résultats pour les extrêmes, alors que la méthode sur l'approche de la région d'influence a conduit à de meilleurs résultats dans le centre de la distribution.Troisièmement, nous avons développé des modèles de relations IDF en utilisant toutes les intensités de précipitations non nulles afin d'inclure efficacement les informations disponibles. Trois approches ont été envisagées. La première est basée sur la propriété d'invariance d'échelle des précipitations, la deuxième sur la formulation générale des IDF et la dernière est purement basée sur les données (data-driven), employant des équations déterminées empiriquement pour modéliser les relations IDF. Les meilleurs résultats ont été obtenus par la troisième. Des courbes IDF à l'échelle de bassins versants ont été générées à partir de ce modèle pour une utilisation opérationnelle, et les distributions marginales journalières dérivées des modèles sont destinées à être utilisées dans un générateur stochastique de précipitation.Enfin, nous avons construit des relations IDAF basées sur une approche data-driven en utilisant un produit de réanalyse radar. Le modèle nous a permis de caractériser l'aléa de précipitations surfaciques pour un continuum d'échelles spatio-temporelles. Dans l'ensemble, les résultats ont permis de mieux comprendre les variabilités saisonnières et régionales de l'aléa de précipitation en Suisse. Pour de courtes durées, les niveaux les plus élevés sont observés en été, tandis qu'à l'échelle journalière, les niveaux les plus élevés sont observés en automne, notamment au Tessin, région identifiée comme la plus exposée aux précipitations extrêmes à toutes les échellesIn an era marked by increasingly volatile weather patterns and their profound impact, reliable prediction of extreme precipitation across multiple scales has never been more challenging. Despite its pivotal significance, accurate prediction remains a formidable challenge, especially in mountainous regions that are particularly susceptible to extreme precipitation hazards. As a result, more robust and efficient tools are needed for reliable prediction.Intensity-Duration-Area-Frequency (IDAF) relationships summarize the main statistical characteristics of extreme precipitation. They are used for areal rainfall hazard quantification, storm characterization, and early warning system development. While Intensity-Duration--Frequency (IDF) relationships for point precipitation have been extensively studied, IDAF relationships, accounting for the area of accumulation, have received far less attention and to our knowledge only for extremes.This thesis aims to model the IDAF relationships for the whole range of non-zero precipitation in topographically complex areas (with application in Switzerland) where robust and flexible models are required due to the strong spatio-temporal variability of precipitation. The key novelty is that IDAF relationships are developed for the whole range of non-zero precipitation intensities, not just extremes. In addition to its usual application, the marginal distributions from the relationships can be utilized in stochastic weather generators.Four objectives were identified and carefully addressed. First, we identified a parsimonious three-parameter model within the extended generalized Pareto distribution (EGPD) family to model the distribution of non-zero precipitation intensities. Second, we build regionalization models based on three regionalization approaches to improve the robustness and reliability of daily precipitation estimates. The first relies on a fast algorithm that defines distinct homogeneous regions based on upper tail similarity, the second is based on the region-of-influence approach, and the third is a spatial approach based on Generalized Additive Model. All the regional models offered improved robustness and reliability in prediction compared to the local model (without regionalization). The GAM-based method was better in the upper tail, while the ROI method performed better in the bulk of the distribution.Third, we developed IDF relationships using all non-zero rainfall intensities for 30 min to 72 hr, making efficient use of available information. Three approaches were considered, the first is based on precipitation scale invariance, the second relies on the general IDF formulation, and the last is purely data-driven, employing empirically determined relationships to model the IDF relationships. The best results were shown by the model based on the data-driven approach. It reproduced the known space and time variability of extreme rainfall across Switzerland, catchment-level IDF curves were generated from it for operational use, and the daily marginal distributions derived from the models are intended to be used in a stochastic weather generator currently developed for operational use.Finally, we constructed IDAF relationships based on a data-driven approach for 1 to 72 hr and 1 to 1,089 km2 at each pixel, utilizing a radar-reanalysis product. The model allowed us to characterize areal precipitation hazards for a continuum of spatio-temporal scales. Overall, the results provided insights into the seasonal and regional patterns of precipitation hazards in Switzerland, highlighting the importance of considering multiple spatio-temporal scales when assessing extreme precipitation hazards. For short durations (e.g. 1 hr), the highest levels are almost exclusively observed in summer, while for the daily scale, the highest levels are observed during autumn, particularly in Ticino, a region identified as the most exposed to extreme precipitation across all scales
3
Eckersten, Sofia. "Updating Rainfall Intensity-Duration-Frequency Curves in Sweden Accounting for the Observed Increase in Rainfall Extremes". Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-283714.
Texto completo da fonteResumo:
Increased extreme precipitation has been documented in many regions around the world, in- cluding central and northern Europe. Global warming increases average temperature, which in turn enhances atmospheric water holding capacity. These changes are believed to increase the frequency and/or intensity of extreme precipitation events. In determining the design storm, or a worst probable storm, for infrastructure design and failure risk assessment, experts commonly assume that statistics of extreme precipitation do not change significantly over time. This so- called notion of stationarity assumes that the statistics of future extreme precipitation events will be similar to those of historical observations. This study investigates the consequences of using a stationary assumption as well as the alternative: a non-stationary framework that con- siders temporal changes in statistics of extremes. Here we evaluate stationary and non-stationary return levels for 10-year to 50-year extreme precipitation events for different durations (1-day, 2-day, ..., 7-day precipitation events), based on the observed daily precipitation from Sweden. Non-stationary frequency analysis is only considered for stations with statistically significant trends over the past 50 years at 95% confidence (i.e., 15 to 39 % out of 139 stations, depend- ing on duration, 1-day, 2-day, ..., 7-day). We estimate non-stationary return levels using the General Extreme Value distribution with time-dependent parameters, inferred using a Bayesian approach. The estimated return levels are then compared in terms of duration, recurrence in- terval and location. The results indicate that a stationary assumption might, when a significant trend exists, underestimate extreme precipitation return levels by up to 40 % in Sweden. This report highlights the importance of considering better methods for estimating the recurrence in- terval of extreme events in a changing climate. This is particularly important for infrastructure design and risk reduction.Ökad extrem nederbörd har dokumenterats globalt, däribland centrala och norra Europa. Den globala uppvärmningen medför en förhöjd medeltemperatur vilket i sin tur ökar avdunstning av vatten från ytor samt atmosfärens förmåga att hålla vatten. Dessa förändringar tros kunna öka och intensifiera nederbörd. Vid bestämning av dimensionerande nederbördsintensiteter för byggnationsprojekt antas idag att frekvensen och storleken av extrem nederbörd inte kommer att förändras i framtiden (stationäritet), vilket i praktiken innebär ingen förändring i klimatet. Den här studien syftar till att undersöka effekten av en icke-stationärt antagande vid skattning av dimensionerande nederbördsintensitet. Icke-stationära och stationära nerderbördsintensiteter föråterkomsttider mellan 10 och 100år bestämdes utifrån daglig och flerdaglig svensk nederbörds- data. Nederbördintensiteterna bestämdes med extremvärdesanalys i mjukvaran NEVA, där den generella extremvärdesfördelningen anpassades till årlig maximum nederbörd på platser i Sverige som påvisade en ökande trend under de senaste 50åren (15% till 39 % utav 139 stationer, beroende på varaktighet). De dimensionerande nederbördsintensiteterna jämfördes sedan med avseende på varaktighet, återkomsttid och plats. Resultaten indikerade på att ett stationärt antagande riskerar att underskatta dimensionerande nederbördsintensiteter för en viss återkomsttid med upp till 40 %. Detta indikerar att antagandet om icke-stationäritet har större betydelse för olika platser i Sverige, vilket skulle kunna ge viktig information vid bestämning av dimensionerande regnintensiteter.
4
Torres, Quintana Eduardo Andrés. "Determinación de curvas IDF en la Región de Antofagasta, Chile". Tesis, Universidad de Chile, 2016. http://repositorio.uchile.cl/handle/2250/138960.
Texto completo da fonteResumo:
Ingeniero CivilEn la región de Antofagasta, ubicada en el extremo norte de Chile, se encuentra una de las zonas más áridas de Sudamérica. La cantidad de ríos y lagos que se ubican en la zona son escasos, y es por esto que la recolección y utilización de aguas no saladas es dificultosa, a la vez que cualquier tipo de proyecto que tenga que ver con hidráulica el recurso hídrico. Sumado a lo anterior, la información hidrológica de la zona es escasa, debido a la baja cantidad de estaciones de medición disponible, con un extenso período continuo de tiempo, ya los pocos estudios actualizados realizados en la zona, siendo el Atlas de "Precipitaciones máximas 1, 2 y 3 días" (DGA 1991) el más actualizado en curvas IDF, lo cual no es adecuado para el diseño de obras hidráulicas en el año 2016, debido a que no incorpora los últimos 25 años de la historia climática de la zona. Por ello, los objetivos del trabajo de título aquí presente serán actualizar los coeficientes de duración y frecuencia, curvas IDF (Intensidad-Duración-Frecuencia) de Antofagasta y presentar isoyetas actualizadas de la II región de Chile. Se realizaron todos los procesos normales en el análisis de datos hidrológicos para distribuciones extremas, conducentes a obtener proyecciones acertadas de la precipitación en escalas de tiempo de 1 a 72 horas, para períodos de retorno entre 2 a 100 años. El proceso realizado se divide en 3 grandes secciones. Primero, la obtención de datos, la cual se realizó a partir de la información de precipitaciones diarias disponible en el Banco Nacional de Aguas y la Dirección Meteorológica de Chile (DMC) y, se incorpora la información de datos horarios de reanálisis de la NASA, y CISL RDA. . Segundo, Análisis de Frecuencia, donde se encontraron las distribuciones que mejor representaban a los datos obtenidos y a partir de estas, se obtuvieron los coeficientes de duración y frecuencia para cada estación. Tercero, la generación de isoyetas correspondientes a la precipitación de período de retorno de 10 años y duración de 1 día, y las curvas Intensidad-Duración-Frecuencia para cada localidad. Los resultados demuestran la utilidad del uso de datos de reanálisis, y que las tormentas en el extremo norte del país han variado entre un 3 a un 15% (tanto para coeficientes de duración como de frecuencia) para algunas zonas, e, incluso, hasta variaciones superiores al 30% (positivas o negativas) para otras en su intensidad promedio para sus diferentes duraciones y períodos de retorno, al igual que en sus valores de cantidad total precipitada por tormenta extrema. Se concluye que los resultados antiguos ya no son adecuados para el diseño de obras hidráulicas actuales Las curvas IDF y las isoyetas presentadas son suficientes por tanto para proyectos que utilicen de las precipitaciones en la región de Antofagasta.
5
Ludwig, Katharina. "Moduli of spin curves". [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=985261056.
Texto completo da fonte
6
Wedeniwski, Sebastian. "Primality tests on commutator curves". [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963295438.
Texto completo da fonte
7
Markwig, Hannah. "The enumeration of plane tropical curves". [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980700736.
Texto completo da fonte
8
Gonçalves, Lidiane Souza. "Relações intensidade-duração-frequência com base em estimativas de precipitação por satélite". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/49152.
Texto completo da fonteResumo:
Atualmente existe uma forte demanda por planos e projetos de drenagem urbana, em vista do crescimento da urbanização e de novas exigências legais. Tais planos e projetos poderão esbarrar em uma ausência de relações Intensidade-Duração-Frequência (IDF) para a maioria das cidades brasileiras, em vista da inexistência de dados pluviográficos que possibilitem sua construção. Neste trabalho, foram estimadas relações IDF para todas as sedes municipais brasileiras a partir de estimativas de precipitação do satélite TRMM, que faz medições com resolução temporal de 3 horas. As chuvas máximas com durações menores do que 3 horas foram obtidas através de relação entre durações. As curvas IDF geradas foram comparadas com relações IDF clássicas, estabelecidas com dados pluviográficos. Adicionalmente, foram comparadas com um método alternativo clássico de obtenção de relações IDF em locais sem dados pluviográficos, em que os totais pluviométricos diários são desagregados para durações menores. Os resultados mostram que as curvas IDF geradas a partir do TRMM possuem incertezas, porém são uma alternativa tão eficiente quanto a utilização de chuvas desagregadas a partir de dados pluviométricos.Nowadays, there is a need for urban drainage projects and planning in Brazil, due to continuing urbanization and a new legal framework. Such plans and projects will demand Intensity-Duration-Frequency (IDF) relations, at least for cities larger than 100.000 inhabitants. Such relations, as well as the pluviographic data which is needed to build them, are often unavailable in Brazil. In this research IDF relations were estimated based on 3-hourly TRMM precipitation estimates. They were then compared to standard IDF relations in sites with pluviographic data. In addition, TRMM IDF relations were compared with another alternative technique for places lacking pluviographic data. Results showed that TRMM estimation of the rainfall still has important uncertainties, but are an alternative method for places without rainfall data.
9
Rosalem, Lívia Malacarne Pinheiro. "Invento para determinação da interceptação de chuva pela serrapilheira em ecossistemas florestais". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-16042018-110427/.
Texto completo da fonteResumo:
A serrapilheira é compreendida como a camada acima do solo formada a partir de materiais que caem da vegetação, funcionando como um mecanismo de interceptação da chuva. Apesar do processo de interceptação ser significativo em áreas de florestas, geralmente esse processo é subestimado ou mesmo negligenciado em modelos hidrológicos, justificado pela dificuldade na obtenção desses dados. Este projeto propôs o desenvolvimento de um equipamento que permite realizar medidas em campo da interceptação da serrapilheira em área de cerrado sensu stricto. Com o equipamento desenvolvido, LID (Litter Interception Device), são realizadas medidas do volume de água retido na serrapilheira e do volume que passa pela serrapilheira, atingindo o solo. O LID foi testado e calibrado em laboratório utilizando chuva simulada de três diferentes intensidades sobre o equipamento, contendo três quantidades diferentes de serrapilheira, 2,97, 1,45 e 0,60 kg.m-2. As amostras de serrapilheira utilizadas nos testes foram retiradas de uma área experimental de mata nativa de cerrado sensu stricto, localizada no município de Itirapina, Estado de São Paulo. As intensidades utilizadas foram definidas a partir de uma curva Intensidade-Duração-Frequência (IDF) gerada para a área experimental. Além do bom funcionamento do LID, os testes serviram para determinar os parâmetros Cmax e Cmin (capacidade máxima e capacidade mínima de armazenamento, respectivamente) da serrapilheira do cerrado sensu stricto. Os resultados mostraram que com o LID são realizadas medições da taxa de retenção de água na serrapilheira (mm.min-1), bem como de sua evaporação (mm.min-1) com precisão. Os testes para calibração do pluviógrafo revelaram que as medidas eram sempre subestimadas, necessitando utilizar uma curva de calibração (R2 = 0,99) para corrigir os registros da intensidade que passa para o pluviógrafo. Os valores encontrados para os parâmetros Cmax (1,0 a 3,07 mm) e Cmin (0,78 a 2,27 mm) corroboram com os encontrados por outros autores para a serrapilheira de diferentes florestas. Verificou-se que a variável quantidade de serrapilheira (kg) influencia mais nesses valores, do que a intensidade da chuva (mm.h-1). Conclui-se com os resultados que o LID pode ser utilizado em estudos que pretendam analisar o papel da serrapilheira em processos hidrológicos, sejam estes para a determinação da interceptação da chuva em campo, ou mesmo na determinação de parâmetros em laboratório.Forest litter is the layer above the ground of the forest formed by materials that fall from the vegetation itself. The vegetation materials are through various stages of decomposition, functioning as a mechanism of rainfall interception. Although the interception process is significant in forested areas, this process is usually underestimated or even neglected in hydrological models due to the difficulties on obtaining these data. We proposed the development of a device that allows the field measurements of the forest litter interception in a cerrado sensu stricto area. The Litter Interception Device (LID), was tested and calibrated in the laboratory. We used simulated rainfall with three different intensities to test the device and also three different amounts of litter, 0.100, 0.230 and 0.470 kg. The litter samples used in the tests were taken from an experimental area of cerrado sensu stricto located in Itirapina, State of São Paulo, Brazil. The intensities of simulated rainfall were obtained from an Intensity-Duration-Frequency (IDF) curve made for the experimental area. Besides the LID functioning tests, the device was tested to determine the parameters Cmax and Cmin (maximum capacity and minimum storage capacity, respectively) of the cerrado sensu stricto forest litter. The results showed that the LID allows measurements of the volume of water retained in the forest litter (mm.min-1) as well as its evaporation (mm.min-1). The pluviometer calibration tests revealed that the measurements were always underestimated, requiring a calibration curve (R2 = 0.99) to correct the volume records that flow to the tipping bucket pluviometer. The values found for Cmax (1.0 - 3.07 mm) and Cmin (0.78 - 2.27 mm) are according with those found by other authors for different kinds of forest litters. It was verified that the variation in the amount of forest litter (kg) influenced more in these values, than the rainfall intensity (mm.min-1) . We concluded that the LID can be used in studies that intend to analyze the role of the forest litter in hydrological processes, whether they area for the determination of the interception of rain in the field or even and in laboratory studies to determine interception parameters of forest litter.
10
Qin, Qing. "Effects of Divergent Selection for Insulin-like Growth Factor I (IGF-I) on Mature Weight and Growth Curves in Angus Cattle". The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275352602.
Texto completo da fonte
11
Kukulies, Stefan. "On Shimura curves in the Schottky locus". [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=985513934.
Texto completo da fonte
12
WESCHENFELDER, Adriana Burin. "Tendências de precipitação pluvial diária e projeção de cenários aplicados à nova curva IDF para Porto Alegre-RS". reponame:Repositório Institucional da CPRM, 2017. http://rigeo.cprm.gov.br/jspui/handle/doc/19015.
Texto completo da fonteResumo:
Submitted by Teresa Cristina Rosenhayme (teresa.rosenhayme@cprm.gov.br) on 2018-02-27T15:45:08Z
No. of bitstreams: 1
Dissertação Adriana Weschenfelder.pdf: 14591888 bytes, checksum: 60cf8512088aec7ed29d7a11bae77c30 (MD5)Approved for entry into archive by Flasleandro Oliveira (flasleandro.oliveira@cprm.gov.br) on 2018-03-02T12:21:13Z (GMT) No. of bitstreams: 1 Dissertação Adriana Weschenfelder.pdf: 14591888 bytes, checksum: 60cf8512088aec7ed29d7a11bae77c30 (MD5)
Approved for entry into archive by Flasleandro Oliveira (flasleandro.oliveira@cprm.gov.br) on 2018-03-02T12:24:07Z (GMT) No. of bitstreams: 1 Dissertação Adriana Weschenfelder.pdf: 14591888 bytes, checksum: 60cf8512088aec7ed29d7a11bae77c30 (MD5)
Made available in DSpace on 2018-03-02T12:24:18Z (GMT). No. of bitstreams: 1 Dissertação Adriana Weschenfelder.pdf: 14591888 bytes, checksum: 60cf8512088aec7ed29d7a11bae77c30 (MD5) Previous issue date: 2017
13
Contardo, Gertrud. "Analysis of light curves of type Ia supernovae". [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=962125938.
Texto completo da fonte
14
Lockyer, Peter Stephen. "Controlling the interpolation of NURBS curves and surfaces". Thesis, University of Birmingham, 2007. http://etheses.bham.ac.uk//id/eprint/6502/.
Texto completo da fonteResumo:
The primary focus of this thesis is to determine the best methods for controlling the interpolation of NURBS curves and surfaces. The various factors that affect the quality of the interpolant are described, and existing methods for controlling them are reviewed. Improved methods are presented for calculating the parameter values, derivative magnitudes, data point spacing and twist vectors, with the aim of producing high quality interpolants with minimal data requirements. A new technique for obtaining the parameter values and derivative magnitudes is evaluated, which constructs a C\(^1\) cubic spline with orthogonal first and second derivatives at specified parametric locations. When this data is used to create a C\(^2\) spline, the resulting interpolant is superior to those constructed using existing parameterisation and derivative magnitude estimation methods. Consideration is given to the spacing of data points, which has a significant impact on the quality of the interpolant. Existing methods are shown to produce poor results with curves that are not circles. Three new methods are proposed that significantly reduce the positional error between the interpolant and original geometry. For constrained surface interpolation, twist vectors must be estimated. A method is proposed that builds on the Adini method, and is shown to have improved error characteristics. In numerical tests, the new method consistently outperforms Adini. Interpolated surfaces are often required to join together smoothly along their boundaries. The constraints for joining surfaces with parametric and geometric continuity are discussed, and the problem of joining \(N\) patches to form an \(N\)-sided region is considered. It is shown that regions with odd \(N\) can be joined with G\(^1\) continuity, but those with even \(N\) or requiring G\(^2\) continuity can only be obtained for specific geometries.
15
Persaud, Vasu Tavasna. "DYNAMIC SPEED MONITORING SYSTEM EFFECTIVENESS ON SHARP CURVES". Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2931.
Texto completo da fonteResumo:
The design of rural interchanges is of critical concern due to the need for the safe transition of vehicles from one high speed roadways to another and vice versa. This transition is accomplished by entry and exit ramps of various forms. The southbound entry loop ramp at the US 27/ US 192 trumpet interchange in Polk County, Florida does not provide such safe transition since historically there has been a high incidence of vehicular off-tracking. The geometry of the southbound entry ramp coupled with high approach speeds are two of the contributing factors. Due to the high cost of interchange modification and ramp realignment, one approach to increasing safety at the interchange is to decrease approach speeds (assumes that speed is a surrogate measure of safety) utilizing a Dynamic Speed Monitoring (DSM) system. The objective of this thesis was to test the effectiveness of such a DSM system at reducing vehicle speeds at the rural US 27/ US 192 trumpet interchange in Polk County, Florida. The system tested was a solar powered, radar based, wireless speed warning system which potentially could be used at traffic locations where it is difficult to secure power and to extended wires. The Measures of Effectiveness (MOEs) for the system were the reduction in mean and variance of speed along with the proportion of vehicles in the higher speed ranges after system implementation. This thesis describes the testing of the DSM effectiveness and involves the documentation of the experiments conducted, the data collected and the analysis of the results. Speed data was collected Before and After installation of the DSM system at two points preceding the southbound entry ramp. Approach speeds were collected at a point 250 feet in advance of the southbound entry ramp curve (also the detection zone of the DSM system radar) and PC speeds were collected at the Point of Curve of southbound entry ramp. Various data sets were analyzed in order to ascertain the systems effectiveness during the day and night, weekdays and weekends, various time periods during the day, and within various speed ranges. The Approach and PC data analysis indicated that the DSM system significantly (at the 95% confidence level) reduced speed mean and variance and increased speed limit/ advisory speed compliance. The Approach mean speed was reduced by 3.58 mph and the PC mean speed was reduced by 1.57 mph. The Approach speed variance was reduced by 3.34 and the PC speed variance was reduced by 0.70 mph. Approach speed limit compliance was increased by 22.27% and PC advisory speed (35 mph) + 5 mph compliance was increased by 11.56% (it was apparent that motorist were utilizing speeds above the advisory speed to navigate the curve). In general, the effectiveness of the DSM system was diminished on weekends as well as during the late night and early morning (12 AM to 7 AM) time periods. This suggested that when there were lower volumes and when motorists' perceived that speed limit enforcement was not as likely, the DSM system effectiveness was reduced. The DSM system resulted in a reduction in the percentage of vehicles utilizing the higher speed ranges (> 45 mph). There was a 62% average reduction in the vehicles that utilized the speed ranges above 57 mph for the Approach data and there was a 36% average reduction in the vehicles that utilized the speed ranges above 45 mph for the PC data. The DSM system resulted in a shift in the distribution of speeds from the higher speed bins to the lower speed bins Before and After installation.M.S.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Civil Engineering MS
16
Sampaio, Marcela Vilar. "Determinação das equações de chuvas intensas em bacias hidrográficas do Rio Grande do Sul". Universidade Federal de Santa Maria, 2011. http://repositorio.ufsm.br/handle/1/3593.
Texto completo da fonteResumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThe design of hydraulic structures to curb the excessive rain, dams, containment basins, terraces, and others are designed with a rainfall that can define the maximum flow of the construction project, satisfying the desired security and is a project economically rational. The lack of precipitation stations with long historical series (20 years) has led to designers from those used in hydraulic relationships that enable the estimation of rain from the project using data from rain gauge stations with greater availability and longer historical series. This study aimed to establish the relationship between intensity, duration and frequency of maximum rainfall in catchment areas of Rio Grande do Sul, from the breakdown of rain 24 hours in duration and aimed at verifying the adherence of the rainfall data theoretical models of probability distribution, to compare different methods of disaggregation of heavy rainfall with durations less than 24 hours and to analyze the variability of the coefficients of the equations of rainfall of different basins of the state. The performance of different methods of disaggregation (Bell, Pfafstetter, Chen, Hernandez and CETESB) employed in the estimation of maximum rainfall for durations shorter than 24 hours with the use of historical series of rainfall stations in watersheds of the RS were compared with values of relations durations obtained in a study by Beltrame et al (1991) on rainfall in the RS. Performance evaluation of different models of breakdown was performed using the coefficient Willmot that allows the analysis of deviations between the estimated values and those obtained by the relationship of duration with adjusted data pluviograms and thereby indicate the methodology which shows better performance. The results allowed the determination of the equations of rainfall for basins of RS by an alternative approach to traditional methodology which presents great difficulties, due to the scarcity of rain gauge records, the difficulties in its production, the low density of the network and pluviographs the short observation period available combined with a thorough job of tabulating, analyzing and interpreting a large amount of rainfalls.
O projeto de estruturas hidráulicas destinadas à contenção do excesso de chuva, como barragens, bacias de contenção, terraços e outras, são projetadas com uma precipitação que possa definir a vazão máxima de projeto da obra, satisfazendo a segurança desejada e que seja um projeto economicamente racional. A falta de estações pluviográficas com séries históricas (20 anos) tem levado a projetistas daquelas obras hidráulicas a utilizaram relações que permitam a estimativa da chuva de projeto a partir de dados oriundos de pluviômetros com maior disponibilidade de estações e séries históricas mais longas. Este trabalho teve como objetivo geral estabelecer a relação entre intensidade, duração e frequência da precipitação máxima, em bacias hidrográficas do Rio Grande Sul, a partir da desagregação de chuvas de 24 horas de duração e como objetivos específicos verificar a aderência dos dados de chuvas a modelos teóricos de distribuição de probabilidade, comparar diferentes metodologias de desagregação de chuvas intensas com durações menores do que 24 horas e analisar a variabilidade dos coeficientes das equações de chuvas intensas das diferentes bacias hidrográficas do RS. O desempenho das diferentes metodologias de desagregação (Bell, Pfafstetter, Chen, Hernandez e CETESB) empregadas nas estimativas das precipitações máximas de durações menores que 24 horas com o uso de séries históricas em estações pluviométricas das bacias hidrográficas do RS foram comparadas com os valores das relações de durações obtidas num trabalho realizado por Beltrame et al (1991) sobre chuvas intensas no RS. A avaliação do desempenho dos diferentes modelos de desagregação será feita através do coeficiente de Willmot que permite a análise dos desvios entre os valores estimados e os obtidos pelas relações de duração ajustadas com dados de pluviogramas e desse modo indicar a metodologia que apresentou melhor desempenho. Os resultados obtidos permitirão a determinação das equações de chuvas intensas para bacias hidrográficas do RS através uma metodologia alternativa a metodologia tradicional que apresenta grandes dificuldades, em função da escassez de registros pluviográficos, de dificuldades para sua obtenção, da baixa densidade da rede de pluviógrafos e do pequeno período de observação disponível aliados a um exaustivo trabalho de tabulação, análise e interpretação de uma grande quantidade de pluviogramas.
17
Raabe, Armin, Robert Wagner e Janek Zimmer. "Power curves of whole wind farms under real operating conditions". Universität Leipzig, 2015. https://ul.qucosa.de/id/qucosa%3A16695.
Texto completo da fonteResumo:
The time-variable production of wind energy must be included into the time-variable energy consumption schemes. This interactive process depends on a precise prediction of weather conditions, particularly of the wind speed (u), and knowledge of the behavior of the consumers. Parallel to the wind speed prediction the wind energy production depends on the technical parameter of the wind turbines, e.g. characterized by a power curve . As we show here, the power curve of a wind farm, consisting of a number of wind turbines, and an individual power curve of a single wind turbine are different. To systematize the relation between wind speed and energy production the power curve is here approximated using an analytic function. This function fits in our case the predicted wind speed with the predicted or actual energy production of a wind farm. Using this function the behavior of wind farms under real operation conditions are shown. The potential of these wind farm power curves are discussed. These curves are used for the power prediction in a power forecast system based on a neural network. The neural network uses the analytic function to systematize the energy output of the wind farms under different wind field conditions. These analytic power curves are helpful tools to characterize the behavior of a wind farm in a good agreement with the measured power output. Additionally, the analysis of some wind parks shows great differences in the expected power output, depending on the wind direction, the position of each wind turbine and the location of the wind farms in their surroundings.Die zeitlich variable Produktion von Windenergie muss in das zeitlich variable Energienutzungsverhalten integriert werden. Dieser Wechselwirkungsprozess schließt eine präzise Wettervorhersage, speziell der Windgeschwindigkeit, und die Kenntnis des Verhaltens der Konsumenten ein. Neben der Windfeldvorhersage hängt die Windenergieproduktion auch von den technischen Parametern der Windenergieanlagen ab, die durch eine Leistungskurve p(u) charakterisiert werden kann. Hier wird gezeigt, dass sich die Leistungsabgabe ganzer Windparks von denen einzelner Anlagen stark unterscheidet. Um diesen Zusammenhang zwischen Windgeschwindigkeit und Energieproduktion zu systematisieren, werden hier die Leistungskurven durch eine analytische Funktion approximiert. Diese Funktion stellt in unserem Fall einen Zusammenhang zwischen der prognostizierten Windgeschwindigkeit und der prognostizierten bzw. tatsächlich eingetretenen Energieproduktion her. Mit dieser Funktion wird das Verhalten von Windparks unter realen Betriebsbedingungen gezeigt. Zusätzlich wird das Potenzial der Windpark-Leistungskurven diskutiert. Diese Kurven werden für die Leistungsvorhersage in einem Energieprognosesystem auf Basis eines neuronalen Netzes verwendet. Das neuronale Netz nutzt die analytische Funktion, um den Energieertrag der Windparks unter verschiedenen Windfeldbedingungen zu systematisieren. Die Analyse einiger Windparks zeigt große Unterschiede zwischen der erwarteten Ausgangsleistung in Abhängigkeit von der Windrichtung, von der Position jeder Windkraftanlage und der Lage des Windparks in seiner Umgebung.
18
Ahn, Sung Joon. "Least squares orthogonal distance fitting of curves and surfaces in space /". Berlin [u.a.] : Springer, 2004. http://www.springerlink.com/link.asp?id=vyegql9cvxu0.
Texto completo da fonte
19
Guha, Pritha. "On scale-scale curves for multivariate data based on rank regions". Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3659/.
Texto completo da fonteResumo:
Quantile-quantile plots are in use to compare univariate distributions for a long time, but as there is no ordering in higher dimension, there is no straight forward generalisation of quantiles for the multivariate data and hence there is no visual tool which can be considered as a generalisation of quantile-quantile plots to compare multivariate distributions. In this work we have considered some notions of multivariate ranks, quantiles and data depths. Based on spatial rank, we have constructed central rank regions and some measures of scale. We proposed a scale-scale plot, which can be used to compare multivariate distributions. Under spherical symmetry, our scale curves have some nice closed form formula, however they are not equivariant under affine transformations. We discussed this issue with illustrations and proposed an affine equivariant version based on data-driven transformations. We established some characterisation results for the proposed affine equivariant scale curves under elliptic symmetry and used the fact to propose some visual test of location and scale in the family of elliptically symmetric distributions. Our proposed scale-scale plot is based on volume functionals of central rank region. We gave some asymptotic results regarding the distribution of the volume functional and constructed a test statistic based on the volume functional. We proposed some asymptotic results regarding the distribution of the test statistic and also studied the power of the proposed test of multivariate normality. As further applications to our scale-scale plots, we discuss the behaviour of our proposed scale-scale plots when the distribution is not elliptically symmetric with illustrations and study the power of the test of for skew elliptic and g and h distribution based on the previously defines test statistic. Among other application of the scale-scale plots, we propose a kurtosis plot, which can be used to study the peakedness and tail behaviour of the multivariate distributions, a visual test of location and scale.
20
Bassi, Rachan. "Absolute instability in curved liquid jets". Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/1654/.
Texto completo da fonteResumo:
We present a study of absolute instability in liquid jets paying particular attention to curved jets formed in the industrial process of prilling. We illustrate the different types of break-up modes identified in experiments on curved jets and also explain the mathematical model used to describe them. Using this mathematical model, we study absolute instability in curved jets undergoing Mode 4 type break-up. The study is extended by including the effects of the density ratio of the liquid to the surrounding gas and gravity. We carry out an experimental study on curved liquid jets concentrating on the Mode 4 break-up regime. Our theoretical results are compared with experiments and very good agreement is found between the two. In addition, we examine absolute instability in thin ligaments that are formed as the jet approaches break-up. This study indicates that the jet undergoes a local absolute instability at pinch-off around its break-up point. A brief investigation of absolute instability in curved non-Newtonian jets is also carried out finding parameters corresponding to convective and absolute instabilities. We also look at jets on very small scales (having radius of the order of micrometers and nanometers) using the interface formation model. The results obtained by using the interface formation model are compared to the classical continuum model and molecular dynamics simulations.
21
Fredenhagen, Stefan. "Dynamics of D-branes in curved backgrounds". Doctoral thesis, [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965704017.
Texto completo da fonte
22
Kumar, Sandeep S. "Elliptic curve cryptography for constrained devices". [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=982216998.
Texto completo da fonte
23
Liu, Junzhi, Ji Ma, Ke Zhang, Prince Ravat, Peter Machata, Stanislav Avdoshenko, Felix Hennersdorf et al. "π-Extended and Curved Antiaromatic Polycyclic Hydrocarbons". ACS Publications, 2017. https://tud.qucosa.de/id/qucosa%3A36577.
Texto completo da fonteResumo:
Synthesis of antiaromatic polycyclic hydrocarbons (PHs) is challenging because the high energy of their highest occupied molecular orbital and low energy of their lowest unoccupied molecular orbital cause them to be reactive and unstable. In this work, two large antiaromatic acene analogues, namely, cyclopenta[pqr]indeno[2,1,7-ijk]tetraphene (CIT, 1a) and cyclopenta[pqr]indeno[7,1,2-cde]picene (CIP, 1b), as well as a curved antiaromatic molecule with 48 πelectrons, dibenzo[a,c]diindeno[7,1,2-fgh:7′,1′,2′-mno]-phenanthro[9,10-k]tetraphene (DPT, 1c), are synthesized on the basis of the corona of indeno[1,2-b]fluorene. These three antiaromatic PHs possess a narrow energy gap down to 1.55 eV and exhibit high kinetic stability under ambient conditions. Moreover, these compounds display reversible electron transfer processes in both the cathodic and anodic regimes. Their cation and anion radicals are characterized by in situ vis−NIR absorption and electron paramagnetic resonance spectroelectrochemistry. The X-ray crystallographic analysis confirms that while CIP and CIT manifest planar structures, DPT shows a curved πconjugated carbon skeleton. The synthetic strategy starting from ortho-substituted benzene units to construct five-membered rings in this work provides a unique entry to novel pentagon-embedding or curved antiaromatic polycyclic hydrocarbons. In addition, besides the detailed chemical and physical investigations, microscale single-crystal fiber field-effect transistors were also fabricated.
24
Prokaj, Jan. "DETECTING CURVED OBJECTS AGAINST CLUTTERED BACKGROUNDS". Master's thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2847.
Texto completo da fonteResumo:
Detecting curved objects against cluttered backgrounds is a hard problem in computer vision. We present new low-level and mid-level features to function in these environments. The low-level features are fast to compute, because they employ an integral image approach, which makes them especially useful in real-time applications. The mid-level features are built from low-level features, and are optimized for curved object detection. The usefulness of these features is tested by designing an object detection algorithm using these features. Object detection is accomplished by transforming the mid-level features into weak classifiers, which then produce a strong classifier using AdaBoost. The resulting strong classifier is then tested on the problem of detecting heads with shoulders. On a database of over 500 images of people, cropped to contain head and shoulders, and with a diverse set of backgrounds, the detection rate is 90% while the false positive rate on a database of 500 negative images is less than 2%.M.S.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Computer Science MS
25
Chacón-Acosta, Guillermo, Inti Pineda e Leonardo Dagdug. "Projection of two-dimensional diffusion in a curved midline and narrow varying width channel embedded on a curved surface". Diffusion fundamentals 20 (2013) 45, S. 1, 2013. https://ul.qucosa.de/id/qucosa%3A13616.
Texto completo da fonte
26
Balzuweit, Gerd, Ralf Der, Michael Herrmann e Martin Welk. "An Algorithm for Generalized Principal Curves with Adaptive Topology in Complex Data Sets". Universität Leipzig, 1997. https://ul.qucosa.de/id/qucosa%3A34516.
Texto completo da fonteResumo:
Generalized principal curves are capable of representing complex
data structures as they may have branching points or may consist of
disconnected parts. For their construction using an unsupervised learning
algorithm the templates need to be structurally adaptive. The present
algorithm meets this goal by a combination of a competitive Hebbian
learning scheme and a self-organizing map algorithm. Whereas the Hebbian
scheme captures the main topological features of the data, in the
map the neighborhood widths are automatically adjusted in order to suppress
the noisy dimensions. It is noteworthy that the procedure which is
natural in prestructured Kohonen nets could be carried over to a neural
gas algorithm which does not use an initial connectivity. The principal
curve is then given by an averaging procedure over the critical
uctuations of the map exploiting noise-induced phase transitions in the neural
gas.
27
Panthou, Gérémy. "Analyse des extrêmes pluviométriques en Afrique de l'Ouest et de leurs évolution au cours des 60 dernières années". Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-01062462.
Texto completo da fonteResumo:
En Afrique de l'Ouest, la diminution brutale de la pluviométrie depuis les années 1970 s'est produite en concomitance avec une augmentation des dommages liés aux inondations. Si une accentuation de la vulnérabilité des populations est indéniable, la question d'une évolution de l'aléa pluviométrique en particulier des pluies les plus intenses reste posée - notamment dans un contexte où le réchauffement climatique devrait s'accompagner d'une intensification du cycle hydrologique globale. Cette thèse s'attache améliorer nos connaissances sur le régime de pluies extrêmes en Afrique de l'Ouest sous-documenté à l'heure actuelle dans les sciences du climat et de l'hydrologie opérationnelle. Le travail s'articule autour des trois objectifs: (i) fournir une vision régionale intégrée de l'organisation spatiale des extrêmes, (ii) étudier l'évolution du régime de précipitations extrêmes en lien avec la variabilité décennale des cumuls pluviométriques annuels, (iii) caractériser les extrêmes pluviométriques en produisant des cartes d'aléa pluviométrique et en étudiant les liens d'échelles entre les extrêmes de pluie à différents résolutions spatio-temporelles. On se base ici sur les données journalières des réseaux nationaux disponibles depuis les années 1950 sur l'Afrique de l'Ouest et actualisées sur le Sahel Central jusqu'en 2010; les données de précipitation à haute résolution disponibles depuis 1990 sur l'observatoire AMMA-CATCH Niger. Les modèles statistiques classiques issus de la théorie des valeurs extrêmes, ont été adaptés pour incorporer des covariables représentant des non-stationnarités spatiales et temporelles dans les pluies extrêmes. On montre la grande robustesse de ces modèles pour estimer les quantiles rares et détecter les tendances régionales dans les séries d'extrêmes. Le cadre théorique des fractales a été utilisé pour modéliser les relations d'échelles spatio-temporelles. On montre ainsi qu'une représentation de type "simple scaling" permet de décrire de manière très satisfaisante ces relations sur la gamme des pas de temps allant de 1 à 24 heures. Les résultats climatologiques confirment que la sécheresse de la fin du XXeme siècle a été avant tout associée à une baisse de l'occurrence des précipitations, leur intensité demeurant relativement inchangée. On note en revanche un comportement singulier sur la dernière décennie durant laquelle un déficit persistant d'occurrence est compensé par une intensification des précipitations qui explique un retour vers une meilleure pluviométrie annuelle, associée cependant à des extrêmes plus marqués et donc porteurs de risque hydrologique.
28
Kapralov, Mikhail. "EFFICIENT INVERSION OF THE CONE BEAM TRANSFORM FOR A GENERAL CLASS OF CURVES". Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2975.
Texto completo da fonteResumo:
We extend an efficient cone beam transform inversion formula, proposed earlier for helices, to a general class of curves. The conditions that describe the class are very natural. Curves C are smooth, without self-intersections, have positive curvature and torsion, do not bend too much in a certain sense, and do not admit lines which are tangent to C at one point and intersect C at another point. A domain U is found where reconstruction is possible with a filtered backprojection type algorithm. Results of numerical experiments demonstrate very good image quality. The algorithm developed is useful for image reconstruction in computerized tomography.M.S.
Department of Mathematics
Sciences
Mathematical Science MS
29
Linke, Julia M., Dmitry Yu Borin e Stefan Odenbach. "First-order reversal curve analysis of magnetoactive elastomers". Royal Society of Chemistry, 2016. https://tud.qucosa.de/id/qucosa%3A30308.
Texto completo da fonteResumo:
The first magnetization loop and the first stress–strain cycle of magnetoactive elastomers (MAEs) in a magnetic field differ considerably from the following loops and cycles, possibly due to the internal restructuring of the magnetic filler particles and the matrix polymer chains. In the present study, the irreversible magnetization processes during the first magnetization of MAEs with different filler compositions and tensile moduli of the matrix are studied by first-order reversal curve (FORC) measurements. For MAEs with mixed magnetic NdFeB/Fe fillers the FORC distributions and magnetization distributions of the first major loop reveal a complex irreversible magnetization behavior at interaction fields Hu < −50 kA m−1 due to the magnetostatic coupling between the magnetically hard NdFeB and the magnetically soft Fe particles. This coupling is enhanced either if the interparticle distance is reduced by particle motion and restructuring or by an increase in the particle densities. If the stiffness of the matrix is increased, the structuring and thus the interparticle interactions are suppressed and the magnetization reversal is dominated by domain processes in the NdFeB particles at high coercive fields of Hc > 600 kA m−1.
30
Konieczny, Martin. "Polyelectrolyte stars meet hard planar and curved walls: confinement, demixing, collapse". [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=984838988.
Texto completo da fonte
31
Lin, Li. "Centrifugal instability of the wake dominated curved compressible mixing layers". Thesis, University of Birmingham, 2008. http://etheses.bham.ac.uk//id/eprint/130/.
Texto completo da fonteResumo:
This investigation is concerned with the linear development of Görtler vortices in the high-Reynolds-number laminar compressible wake behind a flat plate which is aligned with the centreline of a curved mixing layer system. The Görtler modes were previously found to exist within the curved compressible mixing layers by Owen et al. (1997). This study extends the work of Owen et al. (1997) and attempts to demonstrate the effect a wake has on the growth rate and location of such modes. The investigations were made by examining the growth rate and the location of the Görtler modes in the limit of large Görtler number and high wave number within the wake-dominated curved compressible mixing-layer systems based on three wake flow models. An analytical Gaussian wake profile is first used to model the behaviour of the basic flow within the mixing layer at the trailing edge of the splitter plate. It is found that the wake has an amplification effect on the growth of the Görtler instability within the concavely curved, or 'unstably' curved compressible mixing layers. It is also found that within the convexly curved, or 'stably' curved compressible mixing layers the wake modes can occur that would behave differently to the 'thermal modes', which were previously found within the plain curved compressible system by Owen et al. (1997). Another analytic composite model which had some practical applications is then used to predict the behaviour of the modes within the systems. A numerical wake flow model has also been derived to compare with the predictions based on the analytic wake flow models.
32
Gurney, Christopher James. "The stability and control of curved liquid jet break-up". Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/781/.
Texto completo da fonteResumo:
An investigation into the break-up dynamics of a curved liquid jet has been studied. A comprehensive review of previous works on straight and curved jet break-up is given, with a detailed comparison between experimental investigation and theoretical models, showing the full uses and limitations of the linear and nonlinear models. A local stability analysis has been developed which can be used to investigate jet stability at any point on the jet at any time. The use of this model concerning break-up of a ligament and short wave generation at break-up is discussed. The Needham-Leach method is adopted to obtain the behaviour of linear and nonlinear waves in the large spatial and temporal limits. The onset of nonlinear wave instability as an implication in satellite drop formation is discussed. A solution to the jet equation is obtained which shows an example of Wilton's ripples, a feature of many other areas of fluid dynamics that has, to date, not been seen in liquid jet break-up. A vibrating nozzle has also been developed which, when vibrating in frequency regimes discovered in this thesis, can control the jet break-up such that satellite droplets are significantly reduced.
33
Hawkins, Victoria. "Curved liquid jets : effect of scale, rheology and forced disturbances". Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/2800/.
Texto completo da fonteResumo:
The creation of drops from the growth of surface tension instabilities on the surface of liquid jets has been exploited in many industrial applications. Curved jets are relevant to prilling, which creates small spherical pellets from molten material. There is a need to optimise the process to produce pellets of uniform size. The dynamics of the break-up of curved jets is examined, with experiments investigating the effect of scale, rheology and surface tension, with particular focus on pseudoplastic liquids, using laboratory and pilot-scale facilities. The experiments were compared to previous work on Newtonian fluids, and existing numerical simulations, which use the method of finite differences to solve non-linear evolution equations for jet radius and axial velocity. The effect of non-Newtonian rheology on the trajectory of the jet and linear instability are determined using computational and asymptotic methods. The droplet sizes produced by this instability are determined by considering the most unstable wave mode. This enables quantitative comparison with the experiments. The influence of multiple disturbance frequencies (imparted by mechanical vibrations) on the break-up of curved Newtonian jets is investigated. Experimental data was compared with existing numerical models, to see if it is possible to predict where satellite droplets are eradicated.
34
Reeder, John. "Hilbert Space Filling Curve (HSFC) Nearest Neighbor Classifier". Honors in the Major Thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/794.
Texto completo da fonteResumo:
This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucfBachelors
Engineering and Computer Science
Computer Engineering
35
Viehrig, H. W., e C. Zurbuchen. "Anwendung des Master Curve-Konzeptes zur Charakterisierung der Zähigkeit neutronenbestrahlter Reaktordruckbehälterstähle". Forschungszentrum Dresden-Rossendorf, 2007. https://hzdr.qucosa.de/id/qucosa%3A21646.
Texto completo da fonteResumo:
Die Anwendbarkeit des Master Curve-(MC-)Konzepts zur Charakterisierung des Zähigkeitszustandes bestrahlter Reaktordruck¬behälter-(RDB-)Stähle wurde an drei RDB-Stählen überprüft: IAEA-Referenzstahl 3JRQ57, 1JFL11 (vergleichbar mit 22NiMoCr3-7) sowie russischer WWER-440 Grundwerkstoff KAB-B. In Zugversuchen, Charpy-V-Tests, Risswiderstandskurven nach ASTM E1820 und Master Curve Tests zur Bestimmung der Referenztemperatur T0 nach ASTM E1921 wurden der unbestrahlte Ausgangszustand, je drei Bestrahlungszustände bis hin zu Neutronenfluenzen von 100∙10^18 n/cm² (E>1MeV) sowie bei 475°C/100h thermisch ausgeheilte Zustände untersucht. Mit zusätzlichen auf dem MC-Konzept basierenden Auswerteverfahren nach SINTAP, multimodalem MC-Ansatz (MML) sowie der Unified Curve erfolgte die Bewertung des Einflusses von Materialinhomogenitäten und möglicher MC-Formänderung bei hohen Fluenzen. Wie erwartet geht Neutronenbestrahlung mit Verfestigung und Duktilitätsabnahme einher, d.h. Härte, Festigkeitskennwerte, Charpy-V-Übergangstemperaturen T28J und T41J sowie T0 steigen mit der Neutronenfluenz, während die Bruchdehnung und Hochlagenzähigkeit abnehmen. Am bestrahlungsempfindlichsten reagiert der Stahl 3JRQ57, gefolgt von KAB-B und 1JFL11. Durch die Ausheilbehandlung von 475°C/100h erholen sich die Werkstoffkennwerte der Zugversuche, Charpy-V-Tests und MC-Versuche auf den jeweiligen unbestrahlten Ausgangszustand. Die technischen Ersatzkennwerte für duktile Rissinitiierung bleiben relativ unbeeinflusst von der Neutronenbestrahlung. Die MC nach ASTM E1921 beschreibt die Bruchzähigkeits-Temperaturverläufe für alle drei RDB-Stähle in allen Bestrahlungs- und Ausheilzuständen gut. Bei den niedrig und mittel bestrahlten Zuständen liegen meist mehr als 5% der KJc(1T)-Werte unterhalb der MC-Kurve für 5% Versagenswahrscheinlichkeit. Die MC beschreibt den hoch bestrahlte Zustand (ca. 100∙10^18 n/cm², E>1MeV) aller drei RDB-Stähle sehr gut, auch für Daten außerhalb des Gültigkeitsbereiches T0±50K, und auch für den bestrahlungsempfindlichen 3JRQ57 mit inhomogenem Gefüge. Die Unified Curve überbewertet den Einfluss der Neutronenbestrahlung auf die MC-Kurvenform. Eine mögliche Formänderung der MC durch Neutronenbestrahlung konnte bei keinem der drei untersuchten RDB-Stähle nachgewiesen werden.
36
Martin, Josh. "The Kuznets Curve and the case of Indonesia (1960 - 2010)". Thesis, Martin, Josh (2014) The Kuznets Curve and the case of Indonesia (1960 - 2010). Honours thesis, Murdoch University, 2014. https://researchrepository.murdoch.edu.au/id/eprint/41676/.
Texto completo da fonteResumo:
This thesis tested whether or not changing inequality in Indonesia over the period of its rapid transformation from 1960s onwards, aligns with the Kuznets Curve hypothesis. This study was undertaken because of a common view in the Kuznets stream of literature that the inverted-U curve is better tested over time rather that by cross-sectional data. To this end, this thesis first examined the Kuznets literature in detail, followed by testing of Kuznets’s (1955) inverted-U using several sources of inequality data followed by regression analysis of several variables associated with the development process. It was also tested whether other explanations of inequality offered in the Kuznets literature can adequately explain the experience of Indonesia in the period. It was found that Indonesia does not experience the inverted-U in inequality over this time, rather a Ushape curve was observed - precisely the opposite that Kuznets (1955) would predict. It was also found that none of the other common explanations of what determines the income distribution offered in the Kuznets stream of literature - for example, education - could adequately explain the experience of Indonesia in the period. These findings are significant because they provide more evidence to disprove the Kuznets Curve and also to show that income inequality in Indonesia is increasing with no adequate explanation available from the Kuznets stream of literature.
37
Hanek, Robert. "Fitting parametric curve models to images using local self-adapting separation criteria". [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=974166375.
Texto completo da fonte
38
Asabere, Philip. "COMPARISON OF DISPERSION CURVES ACQUIRED USING MULTICHANNEL ANALYSIS OF SURFACE WAVES WITH VARIOUS STRIKER PLATE CONFIGURATIONS". Master's thesis, Temple University Libraries, 2016. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/368445.
Texto completo da fonteResumo:
Civil EngineeringM.S.C.E.
There is growing appreciation and research regarding geophysical methods to evaluate near surface soil properties in geotechnical engineering. Geophysical methods are generally non-destructive test (NDT) methods that do not necessitate traditional sampling of soils. Instead, they rely on application of input signals and deduction of soil properties from the measured response of the domain. Geophysical methods include various seismic, magnetic and nuclear techniques applied at the surface and/or subsurface within boreholes. Surface seismic methods, which include Multichannel Analysis of Surface Waves (MASW), are increasing in usage for geotechnical engineering purposes to evaluate stiffness properties of soils. MASW typically involves using a hammer to impact a base plate (also referred to as a striker plate) to transmit surface waves into the ground. These waves propagate through the underlying soils at a site and are received by an array of geophones placed on the ground surface. The manner in which the waves propagate is primarily influenced by soil stiffness, particularly against shear. Therefore, the signals recorded during an MASW survey can be analyzed to estimate the shear stiffness of the soils at a site, a parameter that is extremely important for seismic-related engineering purposes (e.g., site amplification, liquefaction, etc.). Aluminum plates are routinely used in a large number of MASW studies as a striker plate to couple the energy from a sledgehammer blow to the underlying soil layers. Various researchers have postulated that the material make-up of the striker plate has an effect on the frequency of the generated waves and, for that matter, the depth achieved with a typical MASW survey. For example, a less stiff material such as ultra-high-molecular-weight (UHMW) polyethylene is often recommended to increase low frequency energy of the input surface wave relative to aluminum. However, very limited research work has been performed in this area to systematically ascertain the effects of modifications to the striker plate material. Due to the limited direct research related to striker plates, MASW was utilized in this study to measure the dispersion curve resulting from MASW at various sites in the Philadelphia metropolitan area. Different striker plate configurations were used during testing to systematically quantify their effects on typical MASW results. The proposed striker base plate configurations included a one (1.0) inch thick aluminum plate, a one (1.0) inch thick aluminum plate over additional rubber mats of varying thickness, and multiple ultra-high-molecular-weight (UHMW) polyethylene plates of various thicknesses. The purpose of this testing was to examine the performance of each configuration, particularly at the low frequency range of the dispersion results. Also efforts were made to qualitatively access the durability of the configurations with respect to long term exposure to impact load.
Temple University--Theses
39
Jun, Byungheup. "A study of irregular singular algebraic connections on curves monodromies, canonical decompositions and an example of the determinant of period integrals /". [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965620018.
Texto completo da fonte
40
Sawatzki, Mikael Georg. "Stellenwert der Endosonographie mit einem Curved-array-Schallkopf bei Erkrankungen des Ösophagus, Magen und Pankreas". [S.l.] : [s.n.], 1999. http://deposit.ddb.de/cgi-bin/dokserv?idn=961254386.
Texto completo da fonte
41
Pelzl, Jan. "Practical aspects of curve-based cryptography and cryptanalysis /". Berlin [u.a.] : Europ. Univ.-Verl, 2006. http://deposit.d-nb.de/cgi-bin/dokserv?id=2902855&prov=M&dok_var=1&dok_ext=htm.
Texto completo da fonte
42
Zambrano, Fernando Campo. "Avaliação do perigo de inundações bruscas por meio de modelagem hidrogeomorfológica : estudo de caso, Bacia do Arroio Forromeco-RS". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/163798.
Texto completo da fonteResumo:
O aumento da ocorrência de desastres hidrológicos relacionados a inundações bruscas tem recebido maior atenção dos diversos órgãos em suas diferentes escalas, com o objetivo de reduzir ao máximo suas causas. Justamente por isso, as medidas não estruturais são medidas de extrema importância na prevenção de tais desastres. Uma dessas medidas deve ser o mapeamento de áreas de perigo de inundações. Portanto, o objetivo do presente trabalho foi propor e avaliar o perigo de inundações bruscas por meio de modelagem hidrogeomorfológica na bacia do arroio Forromeco-RS. Para isso, foi utilizado o modelo CAESAR-LISFLOOD, para representar os processos hidrológicos em escala de bacia e canal. Em escala de bacia foram gerados hidrogramas a partir da criação de chuvas de projeto para diferentes tempos de retorno (TR), considerando como base o maior evento registrado nessa bacia associado a um TR de 22 anos. Esses hidrogramas foram utilizados nas simulações em escala de canal para gerar os diferentes mapas de inundação em termos de profundidade e velocidade do fluxo da água. Para analisar as áreas de perigo de inundação, foram determinados os índices de perigo (IP) associados aos diferentes TR, a partir da profundidade e a velocidade d’água. Através das análises do resultado de IP foi criado o mapeamento final de perigo associado a três tempos de retorno (5, 22, e 100 anos). Além disso, estabeleceu-se três zonas para identificar os níveis de perigo, considerando o cenário mais crítico dos três mapas. Os resultados mostraram que a maior área inundada se encontra em alto perigo, ocupando 77% da área total, o que significa que as pessoas que moram nessa região estão em perigo tanto em casa, como fora delas. Ao mesmo tempo as construções estão em alta possiblidade de serem danificadas.The increase in the occurrence of hydrological disasters related to flash floods has begun to be more important for several organs at different scales in order to reduce their magnitude and frequency as much as possible. Precisely because of it, non-structural measures are extremely important measures for preventing such disasters. One of these important measures might be the mapping of flood hazard areas. Therefore, the objective of the present work was to propose and evaluate the flash flood hazard by means of hydrogeomorphic modeling of the Forromeco river basin, Rio Grande do Sul state. Thus, the CAESAR-LISFLOOD model was used to represent the hydrological processes at basin and channel scale. At basin scale hydrographs were generated from the creation of hyetographs for different return periods (RP), considering the largest event recorded in this basin. These hydrographs were used in the channel scale simulations to generate the different flood maps in terms of depth and velocity of water flow. In order to analyze the flood hazard areas, the hazard indexes (HI) associated with the different RPs were determined from the depth and water velocity. Through the IP analysis, the final hazard mapping associated with three RPs (5, 22, and 100 years) was created. In addition, three zones were established to identify the hazard levels, considering the most critical scenario of the three maps. The results showed that the largest flood area is in high degree hazard, occupying 77% of the total area. It indicates that people are in danger both inside and outside houses. At the same time buildings are in high possibility of being damaged.
43
Weigl, Andrew. "Improving security for elliptic curve implementations on smart cards a random number generator test unit /". [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=983478090.
Texto completo da fonte
44
Naujock, Lisa. "DEVELOPMENT OF HYDRAULIC AND SOIL PROPERTIES FOR SOIL AMENDMENTS AND NATIVE SOILS FOR RETENTION PONDS IN MARION COUNTY, FLORIDA". Master's thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2880.
Texto completo da fonteResumo:
The vadose zone plays an important role in managing stormwater. Predicting the water balance and water movement is crucial in ground water remediation to keep water suitable for use. To aid in understanding soils ability to transmit and store water, soil and hydraulic properties were analyzed for soils in Marion County, Florida, and potential soil amendments. Soil and hydraulic properties were examined for two soil amendments and for the soils in Marion County, Florida, at the South Oak and the Hunter's Trace locations. The hydraulic properties measured were the soil moisture retention curve (SMRC) and saturated hydraulic conductivity (Ks). The soil properties measured were the particle-size distribution (PSD) and the specific gravity. From these, the bulk density and porosity were calculated. The SMRC corresponds to the water holding capacities, while the Ks corresponds to the soils ability to transmit water. Both are dependent on the soil properties. The SMRC for the soil amendments and native soils were developed in the laboratory using a Tempe Cell apparatus. In addition, the SMRC was measured in the field at the Hunter's Trace location with time domain reflectometry (TDR) and tensiometer equipment at three depths of 1-ft, 2-ft, and 3-ft over approximate a two month period. The SMRC obtained in the laboratory was compared to two analytical models, Brooks and Corey and van Genuchten, and to the field data. There is a strong correlation between the laboratory, analytical, and field SMRC for both South Oak and Hunter's Trace. In addition, there is a strong correlation between the laboratory SMRC and analytical models for the soil amendments. The Arya and Paris (AP) model, a pedotransfer function, was examined for its accuracy in predicting the SMRC for the soils at South Oak and Hunter's Trace, in addition to the soil amendments. Measuring the SMRC in the lab is a time consuming process; therefore, inferring the SMRC from textural and structural soil properties which are easier measured characteristics would be advantageous.M.S.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Civil Engineering MS
45
Klinke, Gregor. "Benjamin Brittens 'Curlew River' Zwischen Exotismus, Synthese und Adaption". Bärenreiter Verlag, 2000. https://slub.qucosa.de/id/qucosa%3A36625.
Texto completo da fonte
46
Partridge, Lucy. "An experimental and theoretical investigation into the break-up of curved liquid jets in the prilling process". Thesis, University of Birmingham, 2006. http://etheses.bham.ac.uk//id/eprint/82/.
Texto completo da fonteResumo:
A pilot scale study of the dynamics of the break-up of curved liquid jets is presented. This work is motivated by an industrial process called prilling which is used in the manufacture of pellets. In this process a sieve-like cylindrical can spins rapidly on its central vertical axis. Molten liquid is pumped into the top of the can and flows from the holes in the form of curved liquid jets. Experiments are described which were carried out on a pilot scale rig. Some differences between the break-up modes observed in this study and previous work using a small laboratory scale rig are discussed. Previous theories describing break-up mechanisms of curved liquid jets were extended to include viscosity and gravity. Break-up lengths and drop sizes were obtained theoretically and compared with experimental results. Experiments were carried out using insonification, a process where sound waves are fired at the jet to control satellite drop formation. Three different frequencies of wave were used, 10, 100 and 200 Hz at four different rotation rates. It was observed that insonification was successful at eliminating satellite drops at low rotation rates and when frequencies of 100 or 200 Hz were used. Insonification was included in the theory. The theory predicted that insonification eliminated satellite drops for a large range of frequencies in the experimental regimes for sufficiently large acoustic volume. The theory also predicted that satellite drops were eliminated in parameter regimes outside the experimental regimes. The trajectory of the jet was allowed to become unsteady, in a rotating frame of reference. Simulations were carried out in inviscid and viscous regimes.
47
Sproul, Faith M. "Effects of Family Involvement: Early Childhood Cognitive Outcomes Using Longitudinal Growth Curve Models". Diss., Temple University Libraries, 2012. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/186689.
Texto completo da fonteResumo:
School PsychologyPh.D.
Early childhood education and family involvement have been shown to provide a positive impact on students' academic achievement regardless of socioeconomic circumstances and background. They have been regarded as two of the most important protective factors in maximizing outcomes for children at risk, especially those from low-income backgrounds. The overall objective of this study was to examine how family involvement changes over time, whether it predicted cognitive outcomes for preschool populations, and potential variables that mediate the relationship between family involvement and outcomes. Data from the Head Start Impact Study conducted through the Department of Health and Human Services (DHHS) were used to answer the research questions. Exploratory and Confirmatory analysis revealed three dimensions of home involvement based on survey items: involvement related to literacy, numeracy, and family resources. Growth curve models suggested increased levels of involvement as children progressed from preschool to first grade. Higher levels of involvement for Literacy for observed for children in Head Start during the first data collection follow-up. The types of involvement were significantly related to cognitive scores as measured by the PPVT-III and WJ-III Achievement. Parenting styles acted as a mediator between involvement and cognitive outcomes. Implications for policy and practice related to transition services are discussed.
Temple University--Theses
48
Su, Ying. "DESIGNS FOR TESTING LACK OF FIT FOR A CLASS OF SIGMOID CURVE MODELS". Diss., Temple University Libraries, 2012. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/214794.
Texto completo da fonteResumo:
StatisticsPh.D.
Sigmoid curves have found broad applicability in biological sciences and biopharmaceutical research during the last decades. A well planned experiment design is essential to accurately estimate the parameters of the model. In contrast to a large literature and extensive results on optimal designs for linear models, research on the design for nonlinear, including sigmoid curve, models has not kept pace. Furthermore, most of the work in the optimal design literature for nonlinear models concerns the characterization of minimally supported designs. These minimal, optimal designs are frequently criticized for their inability to check goodness of fit, as there are no additional degrees of freedom for the testing. This design issue can be a serious problem, since checking the model adequacy is of particular importance when the model is selected without complete certainty. To assess for lack of fit, we must add at least one extra distinct design point to the experiment. The goal of this dissertation is to identify optimal or highly efficient designs capable of checking the fit for sigmoid curve models. In this dissertation, we consider some commonly used sigmoid curves, including logistic, probit and Gompertz models with two, three, or four parameters. We use D-optimality as our design criterion. We first consider adding one extra point to the design, and consider five alternative designs and discuss their suitability to test for lack of fit. Then we extend the results to include one more additional point to better understand the compromise among the need of detecting lack of fit, maintaining high efficiency and the practical convenience for the practitioners. We then focus on the two-parameter Gompertz model, which is widely used in fitting growth curves yet less studied in literature, and explore three-point designs for testing lack of fit under various error variance structures. One reason that nonlinear design problems are so challenging is that, with nonlinear models, information matrices and optimal designs depend on the unknown model parameters. We propose a strategy to bypass the obstacle of parameter dependence for the theoretical derivation. This dissertation also successfully characterizes many commonly studied sigmoid curves in a generalized way by imposing unified parameterization conditions, which can be generalized and applied in the studies of other sigmoid curves. We also discuss Gompertz model with different error structures in finding an extra point for testing lack of fit.
Temple University--Theses
49
Thiboutot, Monika. "CURES TO STALLED DEVELOPMENT: CAUSES AND SOLUTIONS TO ECONOMIC CRISIS IN SUB-SAHARAN AFRICA". Master's thesis, University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2776.
Texto completo da fonteResumo:
The purpose of this thesis is to investigate some of the contending issues associated with economic underdevelopment in sub-Saharan African states. Specifically, this thesis focuses on the combined effects of World Bank and International Monetary Fund (IMF) economic austerity programs, the increased spread of the HIV/AIDS pandemic, and the continuous democratic deficit on the sluggish economic performance within four sub-Saharan African countries – Ghana, Kenya, Botswana and the Democratic Republic of Congo. The research questions are: are there any unique political, cultural, and economic issues that underscore and determine the path of sub-Saharan African development? What are the potentials for sub-Saharan Africa going beyond its present state of socioeconomic and political underdevelopment? Can sub-Saharan African nation-states truly claim the 21st century? It is hoped that what is learned from examining the situation in these four countries may be generalizeable to other sub-Saharan African states. This thesis has been written with the conviction that sub-Saharan Africa, although it has missed opportunities over the past thirty years, has not completely closed the door on economic development. Although sub-Saharan African conditions have not favored development and there is no simple solution for sub-Saharan Africa's economic and social ills, there are a number of 'common sense' approaches toward sustainable economic and social development. This thesis examines why sub-Saharan Africa's economic crisis has persevered for three decades, and why efforts to establish and uphold more effective economic policies and functioning public institutions have been so much more difficult in sub-Saharan Africa than elsewhere. My account concentrates on political and institutional factors: I explore how the predicament has progressed over the last thirty years, and the repercussions of the long-term nature of this predicament. The focal purpose is to identify and explain the causes which have kept sub-Saharan Africa for several decades mired in an ostensibly permanent crisis. The general theme of the thesis emphasizes that politics and economics are interconnected in sub-Saharan Africa. Moreover, the thesis focuses on the changing role of politics and markets in the process of economic development since the 1970s – and prospects for the future of this region.M.A.
Department of Political Science
Sciences
Political Science
50
Agiro, Abiy T. "Determinants of productivity in hospital-based rural health clinics a growth curve modeling approach". Doctoral diss., University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4831.
Texto completo da fonteResumo:
The Patient Protection and Affordable Care Act of 2010 expanded rural Medicaid and Medicare coverage. However, different vehicles of delivering care (e.g., hospitals, health clinics, etc.) have differing organizational capacity that may or may not enable them to overcome the challenges of expanded provision. Consequently, this research employed structural contingency and organizational performance models to investigate the impact of organizational factors on productivity growth, while recognizing that contextual factors also affect the delivery of care. Latent growth curve modeling was used to study a national panel of 708 U.S. hospital-based Rural Health Clinics for the years 2005 to 2008. Productivity was measured through dynamic slacks-based data envelopment analyses. Unconditional and conditional linear growth curve models were fitted to data. Findings revealed that 1) hospital-based clinics with higher baseline levels of productivity in 2005 had a slower rate of growth in productivity for the years 2006 to 2008, 2) hospital-based clinics with physicians had significantly higher productivity, 3) hospital-based clinics in urban focused areas had significantly higher productivity, 4) newer hospital-based clinics had significantly higher productivity, and 5) prospective payment system was negatively related to the rate of change in productivity growth. Organizational and contextual factors included in this study significantly explained initial differences in productivity but were unable to explain productivity growth. Future research could improve the study by 1) including additional explanatory variables, such as the use of technology and disease management programs, 2) adjusting productivity measures by case mix measures, and 3) conducting truncated panel data regression with Monte Carlo simulation.ID: 030422818; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2011.; Includes bibliographical references (p. 154-165).
Ph.D.
Doctorate
Public Affairs
Health and Public Affairs