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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Inversão da forma de onda completa de dados de sísmica de reflexão rasa / Full waveform inversion of shallow seismic reflection data.

Spadini, Allan Segovia 15 February 2018 (has links)
Este trabalho realizou um estudo sobre a aplicação de algoritmos de inversão da forma de onda completa (FWI) sobre dados de sísmica de reflexão em uma escala rasa ( 0 100 m de profundidade). A FWI foi estudada com o fim de melhorar as velocidades estimadas através do processamento de reflexão PP e PS convencional. Para um melhor entendimento da resposta obtida por este tipo de problema, a inversão foi avaliada sobre dados sintéticos por métodos de busca global e local. Na busca global foi utilizado o algoritmo de Evolução Diferencial que é uma variante de um algoritmo genético. O intuito da busca global foi avaliar a sensibilidade da função objetivo para cada parâmetro do modelo em diferentes janelas de afastamentos em relação à fonte. Na busca local foi utilizado um algoritmo de gradiente conjugado para a estimativa 2D dos parâmetros do meio. Dentre os principais resultados têm-se que a função objetivo é mais sensível aos parâmetros em janelas de afastamentos próximas da fonte. Em tais janelas, dominadas por ondas superficiais, a velocidade da onda S é facilmente estimada. Entretanto, mesmo em janelas mais afastadas a velocidade da onda S é o parâmetro do modelo que se destaca em relação aos demais. Já a busca por todos os parâmetros concomitantemente mostrou-se difícil e implicaria na necessidade de mais iterações do algoritmo de inversão. O método também foi aplicado em dados reais adquiridos no terreno do Instituto de Física da USP. A FWI foi aplicada nestes dados buscando apenas pelos valores de Vs, mantendo os valores de Vp e densidade fixos. A aplicação do algoritmo 2D nestes dados resultaram em valores de Vs coerentes com as velocidades observadas em um ensaio downhole na área. Concluindo, os resultados apresentados na tese mostram que a FWI é aplicável para a melhoria do modelo de velocidade da onda S obtido através do processamento de eventos de reflexão PP e PS. / This work carried out a study on the application of full waveform inversion algorithms (FWI) on reflection seismic data on a shallow scale (0 - 100 m depth). FWI has been studied in order to improve estimated velocities through conventional PP and PS reflection processing. For a better understanding of the response obtained by this type of problem the inversion was evaluated by global and local search methods. In the global search the algorithm employed was the Differential Evolution which is a variant of a genetic algorithm. The aim of the global search was to evaluate the sensitivity of the objective function for each parameter of the model in different windows of distance from the source. In the local search a conjugate gradient algorithm was used for a 2D estimate of the medium parameters. Among the main results is the fact that in a suitable window, for a reflection data acquisition the sensitivity is reduced in relation to a window with geophones closer to the source. However, even in more distant windows the velocity of the S wave is the parameter of the model that stands out in relation to the others. The concomitant search for all parameters at the same time is still difficult and implies the need for more iterations of the inversion algorithm. The method was also applied in a data acquired in the field of the Institute of Physics of USP. The results of the application of the 2D algorithm for this data showed modifications of the provided initial model for a velocity of the S wave coherent with the observed velocities in downhole and lithological informations from this area. In conclusion, the results found that FWI is applicable to improve the S-wave velocity model obtained by processing PP and PS reflection events.
22

Efecto de la tala rasa sobre la vegetación leñosa en los ecosistemas de pinares en la Unidad Silvícola San Andrés perteneciente a la EFI La Palma

Valdés Rodríguez, Nelson January 2003 (has links)
Programa Doctoral conjunto "Desarrollo Sostenible de Bosques Tropicales. Manejo Forestal y Turístico".
23

Inversão da forma de onda completa de dados de sísmica de reflexão rasa / Full waveform inversion of shallow seismic reflection data.

Allan Segovia Spadini 15 February 2018 (has links)
Este trabalho realizou um estudo sobre a aplicação de algoritmos de inversão da forma de onda completa (FWI) sobre dados de sísmica de reflexão em uma escala rasa ( 0 100 m de profundidade). A FWI foi estudada com o fim de melhorar as velocidades estimadas através do processamento de reflexão PP e PS convencional. Para um melhor entendimento da resposta obtida por este tipo de problema, a inversão foi avaliada sobre dados sintéticos por métodos de busca global e local. Na busca global foi utilizado o algoritmo de Evolução Diferencial que é uma variante de um algoritmo genético. O intuito da busca global foi avaliar a sensibilidade da função objetivo para cada parâmetro do modelo em diferentes janelas de afastamentos em relação à fonte. Na busca local foi utilizado um algoritmo de gradiente conjugado para a estimativa 2D dos parâmetros do meio. Dentre os principais resultados têm-se que a função objetivo é mais sensível aos parâmetros em janelas de afastamentos próximas da fonte. Em tais janelas, dominadas por ondas superficiais, a velocidade da onda S é facilmente estimada. Entretanto, mesmo em janelas mais afastadas a velocidade da onda S é o parâmetro do modelo que se destaca em relação aos demais. Já a busca por todos os parâmetros concomitantemente mostrou-se difícil e implicaria na necessidade de mais iterações do algoritmo de inversão. O método também foi aplicado em dados reais adquiridos no terreno do Instituto de Física da USP. A FWI foi aplicada nestes dados buscando apenas pelos valores de Vs, mantendo os valores de Vp e densidade fixos. A aplicação do algoritmo 2D nestes dados resultaram em valores de Vs coerentes com as velocidades observadas em um ensaio downhole na área. Concluindo, os resultados apresentados na tese mostram que a FWI é aplicável para a melhoria do modelo de velocidade da onda S obtido através do processamento de eventos de reflexão PP e PS. / This work carried out a study on the application of full waveform inversion algorithms (FWI) on reflection seismic data on a shallow scale (0 - 100 m depth). FWI has been studied in order to improve estimated velocities through conventional PP and PS reflection processing. For a better understanding of the response obtained by this type of problem the inversion was evaluated by global and local search methods. In the global search the algorithm employed was the Differential Evolution which is a variant of a genetic algorithm. The aim of the global search was to evaluate the sensitivity of the objective function for each parameter of the model in different windows of distance from the source. In the local search a conjugate gradient algorithm was used for a 2D estimate of the medium parameters. Among the main results is the fact that in a suitable window, for a reflection data acquisition the sensitivity is reduced in relation to a window with geophones closer to the source. However, even in more distant windows the velocity of the S wave is the parameter of the model that stands out in relation to the others. The concomitant search for all parameters at the same time is still difficult and implies the need for more iterations of the inversion algorithm. The method was also applied in a data acquired in the field of the Institute of Physics of USP. The results of the application of the 2D algorithm for this data showed modifications of the provided initial model for a velocity of the S wave coherent with the observed velocities in downhole and lithological informations from this area. In conclusion, the results found that FWI is applicable to improve the S-wave velocity model obtained by processing PP and PS reflection events.
24

Aesthetics of emotional acting : an argument for a Rasa-based criticism of Indian cinema and television

Roy, Piyush January 2017 (has links)
The thesis explores elements of Sanskrit drama studies, its philosophy of aesthetics, Hindu theology and Indian cinema studies. It seeks to identify and appreciate the continual influence of a pioneering and influential idea from the Indian subcontinent’s cultural memory and history – the ‘theory of aesthetics’, also known as the ‘Rasa Theory’. The rasa theory is a seminal contribution of the ancient Indian Sanskrit drama textbook, the Natyashastra, whose postulates have provided a definitive template for appreciating and analysing all major fine arts in the Indian sub-continent for over two millennia. No criticism of an art form in India is more devastating than the allegation that it is devoid of rasa. Though ‘rasa’ has many literal meanings like taste, essence and ultimately bliss, in Natyashastra it is used to signify the “essence of emotion” or the final emotional state of ‘relish/reaction/aesthetic experience’ achieved by a spectator while watching a performing art. The thesis uses this fundamental aesthetic influence from India’s cultural memory and heritage to understand its working in the shaping of emotive performances, and the structuring of multiple genre mixing narrative styles in Indian cinema. It identifies and explains how the story telling attributes in Indian cinema, still preserve, transmit and represent, drama and performance aesthetics established 2000 years ago. The chapters are divided into two sections – evidence-led correlation confirming the direct influence of Natyashastra guidelines on Indian filmmaking practices, and arguments-driven proposals on how to use the rasa theory for appreciating cinematic aesthetics. Section One, comprising of the first three chapters, engages with direct evidence of the influence and use of Natyashastra prescriptions and rasa theory expectations in the early years of Indian cinema, when the movie industry was intimately tied to theatre for creative guidance. Section Two, comprising of chapters four to six, goes beyond these conscious engagements to explore the continuing relevance of the concepts of bhava and rasa for studies and methods in film appreciation, and their potential usage in discussing alternate modes of cinematic expression, like melodrama. In this section, recommendations are made on how to re-read and review influential and representative cinematic achievements from different eras, regions and genres of Indian on-screen entertainment, using the rasa theory for better understanding of foundational cinematic attributes like plot construction, performances and directorial achievement in non-realism prioritising on-screen narrations. The thesis shows how to appreciate expressive acting, song and dance performances and melodramatic narratives/ movies using the rasa theory’s prescriptions on good acting in a navarasa exploring drama. It calls for a greater engagement with the theory’s aesthetic appreciation ideas, beyond its current peripheral acknowledgement in academic scholarship as an exotic and ancient review model with doubtful contemporary relevance. My conclusions offer a valuable guide for a fair and better appreciation of dramatic, stylistic and stereotypical acting in cinema that Western models of film criticism privileging the realistic form have been inadequate in comprehending. These findings propose a mode of inclusive aesthetic criticism that enjoys broad application across a wide range of cinematic art genres and national cinema styles using non-Euro/American modes of storytelling, towards the establishment of a humanist film education.
25

Estudo comparativo da resposta das ondas convertidas na investigação rasa: aquisição, processamento e interpretação / Comparative study of the response of converted waves in shallow investigation: acquisition, processing and interpretation.

Shevchenko, Oksana 09 March 2018 (has links)
Visando estudo do método de sísmica multicomponente (3C) na investigação rasa, foram adquiridos dados em duas áreas urbanas da cidade de São Paulo, Brasil, com características geológicas diferentes: Campus da Universidade de São Paulo (USP), situado na zona oeste do município e área da estrutura de Colônia, situada na região de Parelheiros, na zona periférica do município. Na aquisição foram empregados geofones de 3 componentes com frequência natural de 10 Hz e, como fontes sísmicas, o compactador e o impacto de uma marreta. Para realizar o processamento dos dados foi utilizado o pacote Seismic Unix (CWP/SU). Foi observada uma marcada diferença nas respostas dos subsolos entre os dois sítios. Nos dados adquiridos no Campus da USP foram observadas tanto as ondas PP como as ondas convertidas (PSv), no entanto, nos dados obtidos em área de Colônia, não foi possível visualizar as ondas convertidas. A partir das secções da onda PP e da onda PS foi estimada a razão Vp/Vs assim como o coeficiente de Poisson para a área da USP. / In order to study the multicomponent seismic method (3C) to shallow investigation, two data sets were acquired in urban areas of São Paulo city, Brazil, with different geological characteristics. The area of the Campus of São Paulo University (USP) is located in the western part of the city and the area of the structure of Colônia is located in the region of Parelheiros, a peripheral zone of São Paulo. For the data acquisition, it were employed 3C-geophones of 10 Hz and, as seismic sources, hand-operated surface compactor and sledge hammer. For processing were used the Seismic Unix package (CWP / SU). It was observed a marked difference in the subsoil responses between the two sites. In the data acquired in the Campus of USP, both PP waves and converted waves (PSv) was observed; however, in the data obtainedin the Colônia area, it was not possible to visualize the converted waves. For the USP area, the Vp / Vs ratio and Poisson ratio were estimated.
26

Sula Toni Morrisonové: Individualita jako hybný prvek ve vývoji společnosti / Toni Morrison's Sula: Individuality as the Driving Element in the Development of the Society

Mazourková, Tereza January 2012 (has links)
This thesis proceeds from the Toni Morrison's novel Sula and it mainly concentrates on a mutual relationship between an individual and society as reflected in the book. It consists of two main parts. The first one describes some aspects of the African-American history; the second one focuses on the individual characters in Sula and analyzes the Bottom society, charted against principles of US society in general. Individuality as the basic point of this thesis is shown as the moving element in the development of the society that also gives the direction of that development. Relationship between an individual and society is considered dialectic - on one hand, particular individuals participate in the development of the society, destroy stereotypes and violate dogmas; on the other hand, these people are often subdued and limited for the sake of the proper functioning of the society. Primary basis of this work is an assumption of the necessity of individual driving elements in the society for its (social) ceaseless development and subjectivism as the basic point of view on human existence. Key words: human being, gender, race, society, subjectivism, womanism.
27

Estudo comparativo da resposta das ondas convertidas na investigação rasa: aquisição, processamento e interpretação / Comparative study of the response of converted waves in shallow investigation: acquisition, processing and interpretation.

Oksana Shevchenko 09 March 2018 (has links)
Visando estudo do método de sísmica multicomponente (3C) na investigação rasa, foram adquiridos dados em duas áreas urbanas da cidade de São Paulo, Brasil, com características geológicas diferentes: Campus da Universidade de São Paulo (USP), situado na zona oeste do município e área da estrutura de Colônia, situada na região de Parelheiros, na zona periférica do município. Na aquisição foram empregados geofones de 3 componentes com frequência natural de 10 Hz e, como fontes sísmicas, o compactador e o impacto de uma marreta. Para realizar o processamento dos dados foi utilizado o pacote Seismic Unix (CWP/SU). Foi observada uma marcada diferença nas respostas dos subsolos entre os dois sítios. Nos dados adquiridos no Campus da USP foram observadas tanto as ondas PP como as ondas convertidas (PSv), no entanto, nos dados obtidos em área de Colônia, não foi possível visualizar as ondas convertidas. A partir das secções da onda PP e da onda PS foi estimada a razão Vp/Vs assim como o coeficiente de Poisson para a área da USP. / In order to study the multicomponent seismic method (3C) to shallow investigation, two data sets were acquired in urban areas of São Paulo city, Brazil, with different geological characteristics. The area of the Campus of São Paulo University (USP) is located in the western part of the city and the area of the structure of Colônia is located in the region of Parelheiros, a peripheral zone of São Paulo. For the data acquisition, it were employed 3C-geophones of 10 Hz and, as seismic sources, hand-operated surface compactor and sledge hammer. For processing were used the Seismic Unix package (CWP / SU). It was observed a marked difference in the subsoil responses between the two sites. In the data acquired in the Campus of USP, both PP waves and converted waves (PSv) was observed; however, in the data obtainedin the Colônia area, it was not possible to visualize the converted waves. For the USP area, the Vp / Vs ratio and Poisson ratio were estimated.
28

Climatic and Structural Controls on the Geomorphology of Wadi Sana, Highland Southern Yemen

Anderson, Joshua Michael 12 April 2007 (has links)
Middle Holocene climate change forced significant environmental response and influenced human activities throughout southern Arabia. Climate models and proxy data indicate that climate along the southern Arabian peninsula changed from a moist phase, spanning the early to middle Holocene, to an arid phase, which persisted for the last ca. 5,000 years. A weakening and southward shift of the Southwest Indian Monsoon System, forced by northern hemisphere insolation variations in the precession band and/or glacial boundary conditions, is suggested as the mechanism for the abrupt shift to more arid conditions. Geoarchaeological evidence suggests that agriculture was more widespread and evolved alongside the development of irrigation technologies during a period when rainfall was more plentiful than today. Here we investigate the surficial record of the dynamic fluvial response to the late Quaternary climate shift and reconstruct the geochronology of the geomorphic evolution of a significant portion of the ca. 125 km length of Wadi Sana, a north-flowing tributary to the Wadi Hadramout system. Using differential-corrected GPS-based survey, combined with analysis of the sedimentary record, the RASA (Roots of Agriculture in Southern Arabia) Project has created a paleohydrologic reconstruction of Wadi Sana in order to provide a context for understanding how fluvial landscapes, hydrologic regime, and human activity reacted to ivchanging middle Holocene climate. Radiocarbon and luminescence dating of remnant silt terraces suggests that fine-grained sediment began accumulating on an older (late-Pleistocene) coarse cobble surface between 12,000-7,000 years ago and continued aggrading until about 5,000 years ago. Paralleling the climate shift, Wadi Sana began incising and eroding the thick sediment infilling about 4,500 years ago, which has continued to the present time. Field reconnaissance and map analysis reveals structural and lithologic controls on the source and availability of these fluvial sediments for downstream deposition during the late Pleistocene and Holocene. Hydrologic modeling of active present-day channels within Wadi Sana estimates stream velocities at 2.2 m/s and stream discharges of 444 m3/s. We propose that a change in hydrologic regime, driven by the monsoon shift, is the cause of the middle Holocene channel adjustment from an aggradational to incising mode in Wadi Sana.
29

Holocene climate and hydrologic changes recorded in Tufa and Lacustrine deposits in Southern Yemen

Sander, Kirk M 01 June 2006 (has links)
Tufa and lacustrine deposits are useful paleoclimate archives in reconstructing the early to middle Holocene climate and paleohydrology of southern Yemen's Wadi Idim and Wadi Sana, which are north-flowing tributaries to Wadi Hadramawt. Numerical age estimates and oxygen-isotopes are used to assess the onset and cessation of tufa formation and reconstruct the environment of lacustrine sediment deposition in the region in order to understand the broader early to middle Holocene hydrologic system.Numerical age estimates from the studied wadis show a correspondence between early to mid-Holocene humid-phase sediment deposition and the northward shift of the ITCZ, as documented in paleoclimate records from other East Africa -- Arabia -- India continental and marine sediments. The interval between ca. 10-5 ka B.P. corresponds to a period of greater availability of moisture from the Arabian Sea region. Increases in precipitation allowed for a lake and wetland systems to develop, and increased spring discharge contributed to the formation of the tufa. Within the lacustrine sediments are ostracodes, mollusks, and flora casts that are found in a much wetter climate compared to today's hyper-arid environment. This early to mid-Holocene humid phase corresponds with a more northerly positioned ITCZ, which shifted south to its present day position around 5,000 yr B.P.Oxygen isotope measurements from ostracods show a range of isotope values from ~ -4.0%â?? at approximately 10 ka B.P. to ~ -6.0%â?? at approximately 5 ka B.P. Theses values represent the early to middle Holocene pluvial phase. Changes in the oxygen isotopic signature represent a change in evaporation or a possible change in source.The early to middle Hol ocene humid phase also corresponds with periods of agricultural activity, which are being investigated by the archaeological team of the Roots of Agriculture in Southern Arabia Project (RASA). Research into the effects of climate change on human activities, specifically agricultural processes, is the focus of RASA. Southern Arabia offers not only a convergence of three major agricultural regions, but also preserves a sedimentary record of the climate shift that affected the region during the period of study.
30

Kampaně proti rasismu / Campaigns against Racism

ROŽNÍČKOVÁ, Iveta January 2015 (has links)
The submitted diploma thesis "Campaigns against racism" is focused on the analysis of comments which appears on webpage www.youtube.com at videos that contain campaigns against racism. The aim of this diploma thesis is the analysis of the reflexion of the comments that are the contributions under video campaigns against racism on web pages. From the above mentioned goal I determined the following research question: What effect do the campaigns against racism have on the citizens of the Czech Republic? The primary file was formed by comments of www.youtube.com web pages users. The contributors of these comments are a specific group which lay stress on their anonymity. This diploma thesis was to show the understanding of perception of the Roma situation in the Czech Republic. Furthermore it aimed to shed light on which attitude towards the Roma minority Czech inhabitants have.

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