• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 20
  • 13
  • 10
  • 8
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 62
  • 62
  • 52
  • 19
  • 15
  • 12
  • 10
  • 10
  • 10
  • 8
  • 7
  • 7
  • 6
  • 6
  • 6
  • 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.
31

Detekce terénních hran s využitím nástroje sky view faktor / Terrain break-lines detection based on Sky View Factor

Englmaierová, Tereza January 2019 (has links)
Terrain Breakline Detection Using Sky-view factor Abstract The subject of this diploma thesis is to propose the procedure of detecting of terrain breaklines using Sky-view factor. The theoretical part of the diploma thesis first introduces the issue of terrain breaklines detection, which presents the methods known to date and Sky- view factor, which is the focal point of the proposed method. Implementation over real data takes place at four locations in the Czechia (Vítkovice, Hradiště, Strnady and Velenka). Data in the form of raster format is tested. At the end, the results of the proposed method and its verification using two selected methods of field edge detection are presented and evaluated. Achieved results point to Sky-view factor for terrain edge detection. Keywords: terrain breakline, digital terrain model, Sky-view factor, detection terrain breaklines methods
32

Detekce terénních hran s využitím nástroje sky view faktor / Terrain break-lines detection based on Sky View Factor

Englmaierová, Tereza January 2019 (has links)
Terrain Breakline Detection Using Sky-view factor Abstract The subject of this diploma thesis is to propose the procedure of detecting of terrain breaklines using Sky-view factor. The theoretical part of the diploma thesis first introduces the issue of terrain breaklines detection, which presents the methods known to date and Sky- view factor, which is the focal point of the proposed method. Implementation over real data takes place at four locations in the Czechia (Vítkovice, Hradiště, Strnady and Velenka). Data in the form of raster format is tested. At the end, the results of the proposed method and its verification using two selected methods of field edge detection are presented and evaluated. Achieved results point to Sky-view factor for terrain edge detection. Keywords: terrain breakline, digital terrain model, Sky-view factor, detection terrain breaklines methods
33

Framkomlighetsanalys med hjälp av en digital terrängmodell och kartdata / Driveability analysis using a digital terrain model and map data

Edlund, Susanne January 2004 (has links)
<p>Driveability analysis of terrain data offers an important technique for decision support for all kinds of movements in the terrain. The work described in this report uses a high resolution digital terrain model generated from the laser radar data and further processed by the Category Viewer program, and information from the Real Estate Map. Properties of features found in a filtering process are calculated and compared with a set of rules in a knowledge base to get a driveability cost. This cost is then visualized in a graphical user interface. </p><p>An evaluation of what driveability is and what it is affected by is performed, and a general cost function is developed, which can be used even if not all relevant information is available. </p><p>The methods for property and cost calculation need to be developed further, as well as the rules in the knowledge base. However, the implemented program offers a good framework for furtherresearch in the area.</p>
34

Nenusistovėjusio tekėjimo reiškiniai Kruonio HAE reversiniame kanale ir jų modeliavimas / Modeling of fluctuating flow regime in Kruonis pumped storage hydroelectric plant outlet channel

Vaišvila, Andrius 30 May 2012 (has links)
Darbe nagrinėjami nenusistovėjusio vandens tekėjimo reiškiniai, kurie atsiranda Kruonio HAE reversiniame kanale dėl netolygaus hidroagregatų veikimo juos paleidžiant ir stabdant. Tyrimų tikslas - nustatyti nenusistovėjusio tekėjimo dėsningumus Kruonio HAE reversiniame kanale ir jam artimiausioje Kauno marių dalyje. Tyrimų metodas – hidrodinamikos skaitmeninis modeliavimas MIKE21 aplinkoje. Hidrodinamikos modelyje panaudotas reversinio kanalo dugno skaitmeninis reljefo modelis, sudarytas stačiakampių gardelių tinklo (grido) pavidalu pagal naujausius batimetrinių matavimų rezultatus. Elementarių gardelių matmenys 5x5 m. Modelio pakraštinėms sąlygoms aprašyti pasirenkamos laiko funkcijos, kurios išreiškia kiekvieno HAE hidroagregato vandens debito kitimą laiko atžvilgiu įvairių modeliuojamų HAE darbo režimų scenarijuose. Kitoje modelio atviroje riboje nustatomas fiksuotas Kauno marių vandens lygis. Hidrodinamikos modeliavimo rezultatai išvedami ir užrašomi kiekvienu skaičiuojamojo laiko žingsniu, o jų analizė atliekama naudojant MIKE21 programų paketo įrankius. Hidrodinamikos modeliavimo rezultatų tikslumui ir patikimumui įvertinti buvo atlikta modelio patikra (t.y. verifikavimas), kurioje panaudoti realiai išmatuotų vandens lygių dinamikos ir tėkmės vektorių lauko krypčių vizualinių stebėjimų rezultatai. Analizuojant gautus modeliavimo rezultatus buvo nustatyti nenusistovėjusio vandens tekėjimo Kruonio HAE reversiniame kanale dėsningumai, kurie pasireiškia staigaus... [toliau žr. visą tekstą] / This work deals with fluctuations in the water flow regime that occur in the outlet channel of the Kruonis Pumped Storage Plant and are produced by uneven running of hydrounits while starting and stopping them. Research purpose: to determine the patterns of fluctuations in the water flow regime that occur in the outlet channel of the Kruonis Pumped Storage Plant and the nearest part of Kaunas Lagoon. Research method: numerical modeling of hydrodynamics in the MIKE21 environment. A digital terrain model of the reverse channel bottom consisting of a rectangular grid network (grid), made following the latest bathymetric measurements, was used for the hydrodynamic model. The elementary grid cell dimentions in the model were 5x5 m. To describe the boundary conditions of the model, time functions which express the water flow rate changes over time of each hydrounit in different operating modes of the KPSP were chosen. The fixed Kaunas Reservoir water level was set in the model as the other open boundary. The results of the hydrodynamic modeling were output and recorded at each computational time step and their analysis was performed using MIKE21 software package tools. To evaluate the accuracy and reliability of the hydrodynamic simulation results, a verification of the model was performed, which used the results of visual monitoring of actually measured water level dynamics and flow vector field directions . Analyzing the findings of simulation, consistent patterns of the... [to full text]
35

Aplicação da geocomputação a estudos de susceptibilidade de deslizamentos de terra / Geocomputation application to studies of landslides susceptibility

Alessandra Martins Coelho 13 March 2012 (has links)
Esta tese propôs uma metodologia para detecção de áreas susceptíveis a deslizamentos de terra a partir de imagens aéreas, culminando no desenvolvimento de uma ferramenta computacional, denominada SASD/T, para testar a metodologia. Para justificar esta pesquisa, um levantamento sobre os desastres naturais da história brasileira relacionada a deslizamentos de terra e as metodologias utilizadas para a detecção e análise de áreas susceptíveis a deslizamentos de terra foi realizado. Estudos preliminares de visualização 3D e conceitos relacionados ao mapeamento 3D foram realizados. Estereoscopia foi implementada para visualizar tridimensionalmente a região selecionada. As altitudes foram encontradas através de paralaxe, a partir dos pontos homólogos encontrados pelo algoritmo SIFT. Os experimentos foram realizados com imagens da cidade de Nova Friburgo. O experimento inicial mostrou que o resultado obtido utilizando SIFT em conjunto com o filtro proposto, foi bastante significativo ao ser comparado com os resultados de Fernandes (2008) e Carmo (2010), devido ao número de pontos homólogos encontrados e da superfície gerada. Para detectar os locais susceptíveis a deslizamentos, informações como altitude, declividade, orientação e curvatura foram extraídas dos pares estéreos e, em conjunto com as variáveis inseridas pelo usuário, forneceram uma análise de quão uma determinada área é susceptível a deslizamentos. A metodologia proposta pode ser estendida para a avaliação e previsão de riscos de deslizamento de terra de qualquer outra região, uma vez que permite a interação com o usuário, de modo que este especifique as características, os itens e as ponderações necessárias à análise em questão. / The purpose of this thesis is a methodology to detect locations susceptible to landslides from the aerial images, culminating in the development of software, denominated SASD/T, to testing the methodology. To justify this research, a survey about natural disasters in Brazilian history related to landslides and methodologies used for detection and analysis of areas susceptible to landslides was realized. Preliminaries studies of the 3D visualization and concepts related to 3D mapping of an area were carried out. The stereoscopy technique was implemented to visualize three-dimensionally the selected region. Altitudes were found via parallax, from the homologous points found by the SIFT algorithm. The experiments were performed with Nova Friburgo city images. The initial experiment showed that the results obtained using the SIFT algorithm together with the proposed filter was highly significant when compared with the results of Fernandes (2008) and Carmo (2010), due to the number of homologous points found and the generated surface. To detect locations susceptible to landslides, information such as altitude, slope, aspect and curvature areas was extracted from the stereo pairs and, together with the variables entered by the user, was provided an analysis of how a particular area is susceptible to landslides. The proposed methodology can be extended to the evaluation and prediction of landslide risks in any other region, since it allows interaction with the user, so that it specifies the characteristics, the items and the weights needed for the analysis in question.
36

Aplicação da geocomputação a estudos de susceptibilidade de deslizamentos de terra / Geocomputation application to studies of landslides susceptibility

Alessandra Martins Coelho 13 March 2012 (has links)
Esta tese propôs uma metodologia para detecção de áreas susceptíveis a deslizamentos de terra a partir de imagens aéreas, culminando no desenvolvimento de uma ferramenta computacional, denominada SASD/T, para testar a metodologia. Para justificar esta pesquisa, um levantamento sobre os desastres naturais da história brasileira relacionada a deslizamentos de terra e as metodologias utilizadas para a detecção e análise de áreas susceptíveis a deslizamentos de terra foi realizado. Estudos preliminares de visualização 3D e conceitos relacionados ao mapeamento 3D foram realizados. Estereoscopia foi implementada para visualizar tridimensionalmente a região selecionada. As altitudes foram encontradas através de paralaxe, a partir dos pontos homólogos encontrados pelo algoritmo SIFT. Os experimentos foram realizados com imagens da cidade de Nova Friburgo. O experimento inicial mostrou que o resultado obtido utilizando SIFT em conjunto com o filtro proposto, foi bastante significativo ao ser comparado com os resultados de Fernandes (2008) e Carmo (2010), devido ao número de pontos homólogos encontrados e da superfície gerada. Para detectar os locais susceptíveis a deslizamentos, informações como altitude, declividade, orientação e curvatura foram extraídas dos pares estéreos e, em conjunto com as variáveis inseridas pelo usuário, forneceram uma análise de quão uma determinada área é susceptível a deslizamentos. A metodologia proposta pode ser estendida para a avaliação e previsão de riscos de deslizamento de terra de qualquer outra região, uma vez que permite a interação com o usuário, de modo que este especifique as características, os itens e as ponderações necessárias à análise em questão. / The purpose of this thesis is a methodology to detect locations susceptible to landslides from the aerial images, culminating in the development of software, denominated SASD/T, to testing the methodology. To justify this research, a survey about natural disasters in Brazilian history related to landslides and methodologies used for detection and analysis of areas susceptible to landslides was realized. Preliminaries studies of the 3D visualization and concepts related to 3D mapping of an area were carried out. The stereoscopy technique was implemented to visualize three-dimensionally the selected region. Altitudes were found via parallax, from the homologous points found by the SIFT algorithm. The experiments were performed with Nova Friburgo city images. The initial experiment showed that the results obtained using the SIFT algorithm together with the proposed filter was highly significant when compared with the results of Fernandes (2008) and Carmo (2010), due to the number of homologous points found and the generated surface. To detect locations susceptible to landslides, information such as altitude, slope, aspect and curvature areas was extracted from the stereo pairs and, together with the variables entered by the user, was provided an analysis of how a particular area is susceptible to landslides. The proposed methodology can be extended to the evaluation and prediction of landslide risks in any other region, since it allows interaction with the user, so that it specifies the characteristics, the items and the weights needed for the analysis in question.
37

Framkomlighetsanalys med hjälp av en digital terrängmodell och kartdata / Driveability analysis using a digital terrain model and map data

Edlund, Susanne January 2004 (has links)
Driveability analysis of terrain data offers an important technique for decision support for all kinds of movements in the terrain. The work described in this report uses a high resolution digital terrain model generated from the laser radar data and further processed by the Category Viewer program, and information from the Real Estate Map. Properties of features found in a filtering process are calculated and compared with a set of rules in a knowledge base to get a driveability cost. This cost is then visualized in a graphical user interface. An evaluation of what driveability is and what it is affected by is performed, and a general cost function is developed, which can be used even if not all relevant information is available. The methods for property and cost calculation need to be developed further, as well as the rules in the knowledge base. However, the implemented program offers a good framework for furtherresearch in the area.
38

Studie protipovodňových opatření v lokalitě Žabovřesky na Svratce v km 42,000 – 45,000 / Feasibility study of the flood protection measures in the locality of Žabovřesky at the Svratka river at km 42,000 – 45,000

Libosvár, Marek January 2016 (has links)
Diploma Thesis deals with the studies of flood protection measures in locality of Brno - Žabovřesky. The work is mainly focused on the calculation of flood flows (Q1, Q5, Q20, Q100 a Q100 neovlivněný) in the area of interest and to proposal flood control measures. Simulation calculations are performed using a coupled 1D / 2D model of the flow of surface water in the bed of the river and its flood area. The results of hydraulic calculations were within the framework the work processed in the form of maps depths, velocity and inundation. Curves levels were indicated in the longitudinal profiles of watercourses.
39

[en] GEOMETRICAL MODELING OF STRUCTURES USING CAD TECHNIQUES / [es] PROYECTO GEOMÉTRICO DE CARRETERAS CONTROLADO POR COMPUTADOR / [pt] PROJETO GEOMÉTRICO DE ESTRADAS ASSISTIDO POR COMPUTADOR

REYNALDO COSATI MEDEIROS 05 September 2001 (has links)
[pt] O Homem constrói estradas desde a Antigüidade. A técnica de projeto utilizada nos dias de hoje é resultado de um longo caminho de aperfeiçoamento que culminou em uma metodologia que procura atingir os melhores índices técnicos ao menor custo de execução possível. Pode-se dizer que esta tecnologia está bem definida desde o início da década de 40. Por sua vez, esta metodologia para ser otimizada requer uma quantidade enorme de cálculos que só podem ser feitos em tempo hábil com a ajuda de um computador. O trabalho a seguir é uma tentativa de se fazer uma aplicação para auxiliar o projetista na tarefa de projeto geométrico de estradas simplesmente implementando uma técnica consagrada há mais de 50 anos. / [en] Mankind has built roads since antiquity. The road planing techniques used today have been obtained throughout improvements which culminated with a methodology that seeks to combine best technical indexes with the lowest possible execution costs. One can say that this technology has been established since the early forties. However, to be optimized, this methodology requires a whole lot of calculation, that can only be afforded with the aid of computers. The research that follows is a system application with the purpose of making the task of road designing easier, by simply implementing techniques that have been known for over 50 years. / [es] El hombre construye carreteras desde la Antigüedad. La técnica de proyecto utilizada hoy em día es resultado de un largo camino de perfeccionamiento que culminó en una metodología que intenta alcanzar los mejores índices técnicos al menor costo de ejecución posible. Se puede decir que esta tecnología está bien definida desde el início de la década de 40. Por outra parte, esta metodología para ser optimizada requiere una cantidad enorme de cálculos que solo pueden ser realizados en tiempo hábil con ayuda de un computador. Este trabajo constituye um intento de realizar una aplicación para auxiliar al projetista en la tarea de proyecto geométrico de carreteras implementando una técnica consagrada há más de 50 años.
40

A novel empirical model of the k-factor for radiowave propagation in Southern Africa for communication planning applications

Palmer, Andrew J 22 September 2004 (has links)
The objective of this study was to provide an adequate model of the k-factor for scientific radio planning in South Africa for terrestrial propagation. An extensive literature survey played an essential role in the research and provided verification and confirmation for the novelty of the research on historical grounds. The approach of the research was initially structured around theoretical analysis of existing data, which resulted from the work of J. W. Nel. The search for analytical models was extended further to empirical studies of primary data obtained from the South African Weather Service. The methodology of the research was based on software technology, which provided new tools and opportunities to process data effectively and to visualise the results in an innovative manner by a means of digital terrain maps (DTMs) and spreadsheet graphics. MINITAB / Thesis (PhD)--University of Pretoria, 2005. / Electrical, Electronic and Computer Engineering / unrestricted

Page generated in 0.0787 seconds