Spelling suggestions: "subject:"[een] PROBABILISTIC METHODS"" "subject:"[enn] PROBABILISTIC METHODS""
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Investigation of drought severity using probabilistic methodsTeoh, Choo B. January 1990 (has links)
No description available.
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Development of Analytical Probabilistic Models for the Estimation of Rainfall Derived Inflow/Infiltration FrequencyMikalson, Daley Travis 14 December 2011 (has links)
Rainfall derived inflow and infiltration (RDII) is a cause of sanitary sewer overflows and sewers exceeding capacity before the end of their design lives, but it is not well understood. Several methods exist to model RDII in existing sanitary sewers. These models are not applicable for design, which is frequently accomplished by applying constant unit rates. Two analytical probabilistic models are developed to estimate the contribution of RDII to peak flow and volume. The analytical models have been tested against computer simulations using long-term rainfall records and parameters calibrated using actual field data. One model relies on calibrated parameters from the RTK method; a commonly used method requiring a time-consuming calibration process. The second model relies on the R-value parameter of the RTK method, and a time of concentration parameter. By providing better information to designers, these analytical models aim to improve engineering decision-making in the design of sewer systems.
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Development of Analytical Probabilistic Models for the Estimation of Rainfall Derived Inflow/Infiltration FrequencyMikalson, Daley Travis 14 December 2011 (has links)
Rainfall derived inflow and infiltration (RDII) is a cause of sanitary sewer overflows and sewers exceeding capacity before the end of their design lives, but it is not well understood. Several methods exist to model RDII in existing sanitary sewers. These models are not applicable for design, which is frequently accomplished by applying constant unit rates. Two analytical probabilistic models are developed to estimate the contribution of RDII to peak flow and volume. The analytical models have been tested against computer simulations using long-term rainfall records and parameters calibrated using actual field data. One model relies on calibrated parameters from the RTK method; a commonly used method requiring a time-consuming calibration process. The second model relies on the R-value parameter of the RTK method, and a time of concentration parameter. By providing better information to designers, these analytical models aim to improve engineering decision-making in the design of sewer systems.
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[en] METHODOLOGIES FOR POWER SYSTEMS SPINNING RESERVE EVALUATION / [pt] METODOLOGIAS PARA ESTABELECIMENTO DA RESERVA OPERATIVA DE GERAÇÃO EM SISTEMAS DE POTÊNCIAANDREA DE MATTOS REI 18 September 2009 (has links)
[pt] Este trabalho trata das metodologias disponíveis mais utilizadas para a avaliação da reserva girante em sistemas de potência. São apresentadas abordagens determinísticas e probabilísticas. Uma grande variedade de aspectos são considerados e organizados de modo a se obter uma taxionomia metodológica. A aplicação da taxionomia sugerida é ilustrada com a análise de um sistema hipotético, o IEEE Reliability Test System, e do sistema brasileiro das regiões Sul/Sudeste/Centro-Oeste. Com base nos resultados obtidos com a aplicação de tal taxionomia à metodologia atualmente utilizada no Brasil, são apontados aspectos que necessitam de maiores pesquisas. Uma das principais conclusões obtidas revela que a prática atual de se associar os períodos críticos de risco àqueles de maior capacidade em manutenção não possui respaldo prático nem teórico. / [en] This report reviews the most representative techniques currency available for power systems spinning reserve evaluation. Both deterministic and probabilistic approaches are tackled. A broad range of aspects are considered and organized in a practical methodological taxonomy. The application of the suggested taxonomy is illustrated with the aid of hypothetical systems, the IEEE Reliability Test System, and the Brazilian South/Southeast/Midwest System. Based on the diagnosis resulting from the application of the taxonomy to the methodology currently utilized in Brazil, several aspects in need of improvement are pointed out. As one of the main results attained, it shown that, the current practice of considering the critical risk period as coincident with the critical maintenance period, lacks practical evidence and theoretical support.
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Análisis probabilístico de riesgo geotécnico en excavaciones profundas utilizando anclajes post-tensados en edificaciones de Lima Metropolitana / Probabilistic analysis of geotechnical risk in deep excavations using post-tensioned anchors in buildings of Metropolitan LimaAgreda Principe, Santos Oliver, Avila Ascencio, Erick Andrés 30 July 2020 (has links)
La presente investigación tuvo como objetivo principal, determinar el riesgo geotécnico de excavaciones profundas utilizando anclajes post-tensados en edificaciones de Lima Metropolitana, aplicando métodos probabilísticos a partir de un abordaje estadístico simple, basado en la hipótesis fundamental de la distribución normal gaussiana de las variables envueltas.En primer lugar, se utilizó el parámetro fundamental de los anclajes post-tensados, la capacidad última de adherencia en la interacción suelo-lechada de cemento τult, (resistencia en la ruptura). Este parámetro se obtuvo de dieciséis (16) ensayos de arrancamiento a escala natural de anclajes post-tensados cimentados en el conglomerado de Lima Metropolitana, obtenidos de la tesis de maestría de Puelles (2011).
En segundo lugar, se realizó un diseño de anclajes post-tensados de edificaciones en Lima Metropolitana de 3, 4 y 5 anillos de 10.50, 13.50 y 16.50 m de profundidad respectivamente. Para ello, se utilizó la metodología FHWA con el objetivo de obtener la capacidad de carga de diseño (TD) de anclajes post-tensados. Además, se ejecutó modelos y modelamientos en el software Slide v6.0 (método equilibrio límite), para realizar el análisis de estabilidad de los mismos. Para ello, se tuvo en cuenta las siguientes variables: los parámetros geotécnicos representativos de Lima Metropolitana, la profundidad de estudio (10.50 a 16.50 m.) y la sobrecarga de edificaciones colindantes. Por último, con los parámetros obtenidos (τult y TD) se definió las curvas estadísticas de distribución de solicitación y resistencia. Luego, se aplicó los métodos probabilísticos e interpretación respectiva, determinado así el riesgo geotécnico para cada caso de estudio. / The main objective of this research was to determine the geotechnical risk of deep excavations using post-tensioned anchors in buildings in Metropolitan Lima, applying probabilistic methods based on a simple statistical approach, based on the fundamental hypothesis of the Gaussian normal distribution of the variables wrapped.
Firstly, the fundamental parameter of the post-tensioned anchors was used, the ultimate capacity of adhesion in the soil-cement grout interaction τult, (resistance to rupture). This parameter was obtained from sixteen (16) natural scale pull-out tests of post-tensioned anchorages cemented in the conglomerate of Metropolitan Lima, obtained from the master's thesis of Puelles (2011).
Secondly, a design of post-tensioned anchorages of buildings in Metropolitan Lima of 3, 4 and 5 rings of 10.50, 13.50 and 16.50 m depth, respectively, was carried out. For this, the FHWA methodology was used with the objective of obtaining the design load capacity (TD) of post-tensioned anchors. In addition, models and modeling were executed in the Slide v6.0 software (limit equilibrium method), to perform their stability analysis. For this, the following variables were taken into account: the representative geotechnical parameters of Metropolitan Lima, the study depth (10.50 to 16.50 m.) And the overload of neighboring buildings.
Finally, with the obtained parameters (τult and TD) the statistical curves of the distribution of stress and resistance were defined. Then, the probabilistic methods and respective interpretation were applied, thus determining the geotechnical risk for each case study. / Tesis
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[en] PROBABILISTIC METHOD APPLIED TO THE ANALYSIS OF INSULATION FAILURE AND ITS APPLICATION TO THE COST SENSITIVITY ANALYSIS OF A 800 KV TRANSMISSION LINE / [pt] RISCO DE FALHA DO ISOLAMENTO DE LINHAS DE TRANSMISSÃO POR MÉTODO PROBABILÍSTICO E SUA APLICAÇÃO À ANÁLISE DE SENSIBILIDADE DO CUSTO DE UMA LINHA DE 800 KVSTENIO ALVARENGA FILHO 28 December 2007 (has links)
[pt] Com o progressivo crescimento das tensões de operação
dos
sistemas elétricos de transmissão de potência. O método
convencional de coordenação de isolamento vai-se tornar
ineficiente e, devido a esta circunstância, fez-se
necessária a criação do método probabilístico de
coordenação de isolamento para surtos de manobra. No
presente trabalho é apresentado o já acima citado método
probabilístico, um programa de computador que tem por
objetivo o cálculo do risco de falha do isolamento de
uma
linha de transmissão e, ainda, uma análise de
sensibilidade do custo de uma linha de 800 KV com os
diversos parâmetros que vão influir nesse custo.
O presente trabalho vai-se afigurar bastante prático
devido ao fato de ele apresentar o que se faz,
atualmente,
em termos de coordenação de isolamento de linha bem como
de subestação / [en] The progressive growth of power system operating voltages
imposes several constraints to the application of the
conventional approach to insulation coordination. As a
consequence a statistical approach to the problem was
developed concerning switching surges. This paper explains
the method mentioned above and introduces a computer
program that calculates the risk of failure for the
insulation of a transmission line. A sesitivity cost
analysis of a 800 KV transmission line, as well as the
various parameters involved, is also presented. Emphasis
is given to the practical aspects of this work, for it
presents the modern techniques used nowadays in solving
the problems of power station and transmision line
insulation coordination.
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PROPER SIZING OF INFILTRATION TRENCHES & BIORETENTION CELLS FOR URBAN STORMWATER MANAGEMENT PURPOSESRowe, Elizabeth January 2019 (has links)
The Ministry of Environment and Climate Change establishes design criteria for the sizing of Low Impact Development (LID) practices in the province of Ontario. The current sizing standards are based on the concept of the 90th percentile storm and require LIDs to provide enough storage capacity to store catchment runoff from a 25 mm rainfall event. The notion of 90th percentile storm means that 90% of all rainfall events have event volumes below a 25 mm rainfall event. This research examines the performance and cost of infiltration trenches and bioretention cells sized for alternative sizing standards ranging from 5–50 mm. Analytical probabilistic equations are used to determine the runoff reduction rates of infiltration trenches and bioretention cells, while the Sustainable Technologies Evaluation Program (STEP)’s LID Practices Costing Tool is used to estimate the overall cost of each LID. The costs are used to create a ratio denoted the fraction of maximum cost by dividing each cost by the cost of the 50 mm sized LID to receive a unitless ratio. This ratio is compared with the runoff reduction rates of both LIDs. Four different catchment sizes and various soil types are included to broaden the scope of the analysis and make the conclusions more dependable. Results indicate that the current sizing standard of 25 mm is probably too high and not cost-effective. In fact, depending on the type of soil and LID, little increase in performance occurs while there is a large increase in cost. A new methodology is proposed for setting sizing criteria for infiltration trenches and bioretention cells which focuses on achieving a desired capture efficiency instead of a required volume of rainfall. The method proposes using the capture efficiency, fraction of maximum cost and sizing criteria to determine what value is an economically more justifiable sizing standard based on individual catchment size and soil type. Use of the analytical probabilistic approach allows for the capture efficiency to be easily calculated and provides better sizing targets on a case by case basis. Recommending a specific capture efficiency can be more uniformly applied LID design in any soil conditions or any catchment size. This can reduce government spending when building LIDs and greatly reduce the possibility of over-design. / Thesis / Master of Applied Science (MASc)
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Numbers and topologiesShi, Lingsheng 10 July 2003 (has links)
In der Ramsey Theorie fuer Graphen haben Burr und Erdos vor nunmehr fast dreissig Jahren zwei Vermutungen formuliert, die sich als richtungsweisend erwiesen haben. Es geht darum diejenigen Graphen zu charakterisieren, deren Ramsey Zahlen linear in der Anzahl der Knoten wachsen. Diese Vermutungen besagen, dass Ramsey Zahlen linear fuer alle degenerierten Graphen wachsen und dass die Ramsey Zahlen von Wuerfeln linear wachsen. Ein Ziel dieser Dissertation ist es, abgeschwaechte Varianten dieser Vermutungen zu beweisen. In der topologischen Ramseytheorie bewies Kojman vor kurzem eine topologische Umkehrung des Satzes von Hindman und fuehrte gleichzeitig sogenannte Hindman-Raeume und van der Waerden-Raeume ein (beide sind eine Teilmenge der folgenkompakten Raeume), die jeweils zum Satz von Hindman beziehungsweise zum Satz von van der Waerden korrespondieren. In der Dissertation wird zum einen eine Verstaerkung der Umkehrung des Satzes von van der Waerden bewiesen. Weiterhin wird der Begriff der Differentialkompaktheit eingefuehrt, der sich in diesem Zusammenhang ergibt und der eng mit Hindman-Raeumen verknuepft ist. Dabei wird auch die Beziehung zwischen Differentialkompaktheit und anderen topologischen Raeumen untersucht. Im letzten Abschnitt des zweiten Teils werden kompakte dynamische Systeme verwendet, um ein klassisches Ramsey-Ergebnis von Brown und Hindman et al. ueber stueckweise syndetische Mengen ueber natuerlichen Zahlen und diskreten Halbgruppen auf lokal zusammenhaengende Halbgruppen zu verallgemeinern. / In graph Ramsey theory, Burr and Erdos in 1970s posed two conjectures which may be considered as initial steps toward the problem of characterizing the set of graphs for which Ramsey numbers grow linearly in their orders. One conjecture is that Ramsey numbers grow linearly for all degenerate graphs and the other is that Ramsey numbers grow linearly for cubes. Though unable to settle these two conjectures, we have contributed many weaker versions that support the likely truth of the first conjecture and obtained a polynomial upper bound for the Ramsey numbers of cubes that considerably improves all previous bounds and comes close to the linear bound in the second conjecture. In topological Ramsey theory, Kojman recently observed a topological converse of Hindman's theorem and then introduced the so-called Hindman space and van der Waerden space (both of which are stronger than sequentially compact spaces) corresponding respectively to Hindman's theorem and van der Waerden's theorem. In this thesis, we will strengthen the topological converse of Hindman's theorem by using canonical Ramsey theorem, and introduce differential compactness that arises naturally in this context and study its relations to other spaces as well. Also by using compact dynamical systems, we will extend a classical Ramsey type theorem of Brown and Hindman et al on piecewise syndetic sets from natural numbers and discrete semigroups to locally connected semigroups.
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Kinetic Monte Carlo Methods for Computing First Capture Time Distributions in Models of Diffusive AbsorptionSchmidt, Daniel 01 January 2017 (has links)
In this paper, we consider the capture dynamics of a particle undergoing a random walk above a sheet of absorbing traps. In particular, we seek to characterize the distribution in time from when the particle is released to when it is absorbed. This problem is motivated by the study of lymphocytes in the human blood stream; for a particle near the surface of a lymphocyte, how long will it take for the particle to be captured? We model this problem as a diffusive process with a mixture of reflecting and absorbing boundary conditions. The model is analyzed from two approaches. The first is a numerical simulation using a Kinetic Monte Carlo (KMC) method that exploits exact solutions to accelerate a particle-based simulation of the capture time. A notable advantage of KMC is that run time is independent of how far from the traps one begins. We compare our results to the second approach, which is asymptotic approximations of the FPT distribution for particles that start far from the traps. Our goal is to validate the efficacy of homogenizing the surface boundary conditions, replacing the reflecting (Neumann) and absorbing (Dirichlet) boundary conditions with a mixed (Robin) boundary condition.
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[en] PROBABILISTIC ANALYSES OF SLOPES AND RETAINMENTS STABILITY / [pt] ANÁLISES PROBABILÍSTICAS DA ESTABILIDADE DE TALUDES E CONTENÇÕESJOAO VICENTE FALABELLA FABRICIO 24 August 2006 (has links)
[pt] Os projetos geotécnicos são, em geral, avaliados através
do cálculo de
um coeficiente de segurança, obtido de forma
determinística. A presente
pesquisa tem como objetivo a comparação de dois métodos
probabilísticos
(Estimativas Pontuais e Segundo Momento) empregados em
análises de
estabilidade. Os métodos probabilísticos quantificam as
incertezas oriundas da
variabilidade dos parâmetros geotécnicos, calculando-se um
índice de
confiabilidade (beta), que expressa o quanto o fator de
segurança é confiável. No entanto, o índice b é um
parâmetro relativo, pois não exprime todas as
incertezas contidas em um projeto geotécnico. O trabalho
apresenta uma
comparação das análises probabilísticas de estabilidade da
barragem de
Curuá-Una, no Pará, e de um muro de arrimo, em São
Fidélis, no Estado do
Rio de Janeiro. No caso da barragem, estudou-se a
influência de um eventual
aumento no nível d´água do reservatório no cálculo da
probabilidade de
ruptura. Para o muro, foram consideradas diversas alturas
do nível d´água no
retroaterro a montante. As análises enfocaram, ainda,
detalhes dos métodos
probabilísticos, no que se refere à aplicabilidade para
projetos práticos.
Verificou-se que o método do Segundo Momento é de mais
fácil utilização em
geotecnia. Recomenda-se, portanto, a sua aplicação em
conjunto com as
análises determinísticas, mais usuais na prática. / [en] Geotechnical projects are generaly assessed through the
calculus of the
safety factor obtained by deterministic methodologies. The
purpose of the
present research work is to compare two probabilistic
methods (Estimate
Punctual and Second Moment) employed in stability
analyses. Probabilistic
methods quantify the uncertainties derived from the
variability of geotechnical
parameters, calculating a confidence ratio that expresses
how reliable the safety
factor is. However, the ratio is a relative parameter,
since it does not account for
all the uncertainties contained in a geotechnical project.
In view of this situation,
the study compares the stability probabilistic analyses of
Curuá-Una dam, in
Pará, and those of a retaining wall in São Fidélis, Rio de
Janeiro. Regarding the
dam, the influence of a possible rise in the resevoir
water level in the calculus of
failure probability has been investigated. In respect to
the wall, several water
levels have been considered in the upstream backfill.
Moreover, the analyses
have focused on the details of probabilistic methods and
their application to
practical projects. It has been verified that the Second
Moment Method is more
easily employed in geothecnics. Therefore, it is
recommended that it should be
applied together with the deterministic analyses currently
used in practice.
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