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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.
1

Dynamic thermal management in chip multiprocessor systems

Liu, Chih-Chun 15 May 2009 (has links)
Recently, processor power density has been increasing at an alarming rate result- ing in high on-chip temperature. Higher temperature increases current leakage and causes poor reliability. In our research, we ¯rst propose a Predictive Dynamic Ther- mal Management (PDTM) based on Application-based Thermal Model (ABTM) and Core-based Thermal Model (CBTM) in the multicore systems. Based on predicted temperature from ABTM and CBTM, the proposed PDTM can maintain the system temperature below a desired level by moving the running application from the possi- ble overheated core to the future coolest core (migration) and reducing the processor resources (priority scheduling) within multicore systems. Furthermore, we present the Thermal Correlative Thermal Management (TCDTM), which incorporates three main components: Statistical Workload Estimation (SWE), Future Temperature Estima- tion Model (FTEM) and Temperature-Aware Thread Controller (TATC), to model the thermal correlation e®ect and distinguish the thermal contributions from appli- cations with di®erent workload behaviors at run time in the CMP systems. The pro- posed PDTM and TCDTM enable the exploration of the tradeo® between throughput and fairness in temperature-constrained multicore systems.
2

Digital Terrain Models Generation from Airborne LiDAR Point Clouds Using A Multi-scale Terrain Filtering Method

Chen, Hufeng 22 May 2012 (has links)
A Digital Terrain Model (DTM) is an important topographic product, required in many applications. Data needed to create a DTM was traditionally obtained via land surveying, however this method can be costly and time consuming depending on the size of the geographic area. Over time, the land surveying was partially replaced by photogrammetry. Today, airborne Light Detection and Ranging (LiDAR) has become another powerful alternative that collect 3D point clouds for digital surface models (DSM) acquisition. LiDAR is especially useful when dealing with heavily vegetated areas using a canopy penetration feature of laser pulse. Nowadays, LiDAR plays an important role in DTM generation. This thesis presents a hierarchical recovery method to generate DTMs from a cloud of 3D points composed of “single returns” and “multiple returns” from laser pulses using the idea of layering. The proposed method will begin by registering the last return points, then layering them. The layering is done by dividing the points into different height layers and assigning layer numbers to each point. The layer numbers are used as a comparison feature in a later identification process. Then a series of rasterized pyramid levels, which consists of the lowest points in each cell, are generated. After layering, outliers are removed; cells in the top level are assumed as terrain points and used as references for identifying cells in the second level. The identification process will identify the cells of the second level into terrain cells and off-terrain cells, and an interpolation will then occur in the cells which identified as off-terrain. The interpolated level will be used as references for the next level and the same process is then repeated for each level that comes after. Once this process has been completed for the bottom level, the proposed method adjusts the results based on the first return feedback, followed by another interpolation. As a result, the final DTM is produced. The developed method is data driven, and does not assume a prior knowledge about the scene complexity. The proposed method was tested with three airborne LiDAR datasets, covering different terrain types and filtering difficulties. Results illustrated that the proposed method can perform well for areas of flat terrain or gentle slope A comparative study was conducted over existing filters and showed that results of the proposed method has similar accuracy in above mentioned area and faster speed than two comparing algorithms.
3

Digital Terrain Models Generation from Airborne LiDAR Point Clouds Using A Multi-scale Terrain Filtering Method

Chen, Hufeng 22 May 2012 (has links)
A Digital Terrain Model (DTM) is an important topographic product, required in many applications. Data needed to create a DTM was traditionally obtained via land surveying, however this method can be costly and time consuming depending on the size of the geographic area. Over time, the land surveying was partially replaced by photogrammetry. Today, airborne Light Detection and Ranging (LiDAR) has become another powerful alternative that collect 3D point clouds for digital surface models (DSM) acquisition. LiDAR is especially useful when dealing with heavily vegetated areas using a canopy penetration feature of laser pulse. Nowadays, LiDAR plays an important role in DTM generation. This thesis presents a hierarchical recovery method to generate DTMs from a cloud of 3D points composed of “single returns” and “multiple returns” from laser pulses using the idea of layering. The proposed method will begin by registering the last return points, then layering them. The layering is done by dividing the points into different height layers and assigning layer numbers to each point. The layer numbers are used as a comparison feature in a later identification process. Then a series of rasterized pyramid levels, which consists of the lowest points in each cell, are generated. After layering, outliers are removed; cells in the top level are assumed as terrain points and used as references for identifying cells in the second level. The identification process will identify the cells of the second level into terrain cells and off-terrain cells, and an interpolation will then occur in the cells which identified as off-terrain. The interpolated level will be used as references for the next level and the same process is then repeated for each level that comes after. Once this process has been completed for the bottom level, the proposed method adjusts the results based on the first return feedback, followed by another interpolation. As a result, the final DTM is produced. The developed method is data driven, and does not assume a prior knowledge about the scene complexity. The proposed method was tested with three airborne LiDAR datasets, covering different terrain types and filtering difficulties. Results illustrated that the proposed method can perform well for areas of flat terrain or gentle slope A comparative study was conducted over existing filters and showed that results of the proposed method has similar accuracy in above mentioned area and faster speed than two comparing algorithms.
4

A Hybrid Model for DTM generation from LIDAR Data

Lee, Hyun Seung 11 December 2004 (has links)
This dissertation introduces an innovative technique to extract ground elevation models using smallootprint LIDAR data. This technique consists of a preprocessing step, ground modeling, and interpolation. In the preprocessing step, much of the non-terrain points are eliminated using a histogram-based clustering technique. Then, in the ground modeling stage, the information such as elevation and slope between nearest neighbor points is extracted. This step corresponds to an outlier detection process. In this stage, residuals and gradient indices for elevation and slope, are introduced. These indices are investigated for a constructed 95% confidence interval to discard the remaining non-terrain points. Finally, using spline interpolation, a smooth ground surface is generated. Experimental results show that the presented technique is more robust and yields better results compared to existing techniques, such as linear prediction, modified linear prediction, and adaptive smoothing, in terms of the root mean squared error, absolute mean, and absolute standard deviation. Furthermore, the possibility of using a ground trend model developed from specific tree height measurements is investigated. For this analysis, a statistical regression analysis model is used. Performing this analysis, a 0.63 R-squared value is obtained. This result indicates that the LIDAR ground surface obtained from the presented algorithm is related to the true ground surface.
5

Extraction of DTM from Satellite Images Using Neural Networks

Tapper, Gustav January 2016 (has links)
This thesis presents a way to generate a Digital Terrain Model (dtm) from a Digital Surface Model (dsm) and multi spectral images (including the Near Infrared (nir) color band). An Artificial Neural Network (ann) is used to pre-classify the dsm and multi spectral images. This in turn is used to filter the dsm to a dtm. The use of an ann as a classifier provided good results. Additionally, the addition of the nir color band resulted in an improvement of the accuracy of the classifier. Using the classifier, a dtm was easily extracted without removing natural edges or height variations in the forests and cities. These challenges are handled with great satisfaction as compared to earlier methods.
6

Análise de técnicas para o estabelecimento de modelos digitais de terrenos - DTM / not available

Campos, Ilce de Oliveira 17 March 1995 (has links)
A representação do relevo topográfico, foi durante muito tempo uma preocupação para os profissionais da área de topografia. O traçado de curvas de nível a partir de um levantamento era feito manualmente, com a determinação dos valores intermediários através de interpolação linear. Com o desenvolvimento da informática e sua introdução para o tratamento de dados em mensuração, surgiu uma nova tecnologia que permite a geração automática de um modelo que descreve analiticamente a superfície topográfica, trata-se dos MODELOS DIGITAIS DE TERRENOS (DTM). Esses modelos constituem uma ferramenta importante no desenvolvimento de vários projetos, tais como, projetos de vias, intersecções, movimento de terra (corte/aterro), drenagem, parcelamento do solo (loteamentos) e outros. O presente trabalho tem como objetivo fazer uma abordagem dos aspectos relativos às técnicas para o estabelecimento desses modelos, descrevendo os principais métodos de aquisição de dados, de interpolação e o processo de geração dos modelos. Finalmente é descrito um panorama do desenvolvimento desses sistemas com suas principais aplicações. / The representation of the topography surface was for a long time the main proposal by the surveyer engenneres. Threading of the contour for surveying is usually made handly with the mean values obtained through the linear interpolation. The development of computer science provide an easier manner of data treatment in measuring. As a result, a new technology was introduced to generate automatically a model for the mathematic description of the topography. They are called of Digital Terrain Model (DTM). These models are very important tool for the development of several projects, such as, highway and intersection projects and land movements (cut/fill), draining, lands parceling and others. This paper has as objective to focus the technics to use these models, describing the main methods to obtain the data, interpolation and process to generate the models. Finally, it is described the development of these systems and it\'s main application.
7

Análise de técnicas para o estabelecimento de modelos digitais de terrenos - DTM / not available

Ilce de Oliveira Campos 17 March 1995 (has links)
A representação do relevo topográfico, foi durante muito tempo uma preocupação para os profissionais da área de topografia. O traçado de curvas de nível a partir de um levantamento era feito manualmente, com a determinação dos valores intermediários através de interpolação linear. Com o desenvolvimento da informática e sua introdução para o tratamento de dados em mensuração, surgiu uma nova tecnologia que permite a geração automática de um modelo que descreve analiticamente a superfície topográfica, trata-se dos MODELOS DIGITAIS DE TERRENOS (DTM). Esses modelos constituem uma ferramenta importante no desenvolvimento de vários projetos, tais como, projetos de vias, intersecções, movimento de terra (corte/aterro), drenagem, parcelamento do solo (loteamentos) e outros. O presente trabalho tem como objetivo fazer uma abordagem dos aspectos relativos às técnicas para o estabelecimento desses modelos, descrevendo os principais métodos de aquisição de dados, de interpolação e o processo de geração dos modelos. Finalmente é descrito um panorama do desenvolvimento desses sistemas com suas principais aplicações. / The representation of the topography surface was for a long time the main proposal by the surveyer engenneres. Threading of the contour for surveying is usually made handly with the mean values obtained through the linear interpolation. The development of computer science provide an easier manner of data treatment in measuring. As a result, a new technology was introduced to generate automatically a model for the mathematic description of the topography. They are called of Digital Terrain Model (DTM). These models are very important tool for the development of several projects, such as, highway and intersection projects and land movements (cut/fill), draining, lands parceling and others. This paper has as objective to focus the technics to use these models, describing the main methods to obtain the data, interpolation and process to generate the models. Finally, it is described the development of these systems and it\'s main application.
8

Condições de saúde bucal de usuários de cocaína e/ou crack em quatro áreas da cidade de Salvador

Teixeira Neto, Altino 12 May 2017 (has links)
Submitted by Programa de Pós-Graduação em Odontologia Saúde (mestrodo@ufba.br) on 2017-11-13T15:00:45Z No. of bitstreams: 1 Tese Altino FINAL.pdf: 2068616 bytes, checksum: 27b47608fca03277f32d911d7ca60c1b (MD5) / Approved for entry into archive by Delba Rosa (delba@ufba.br) on 2017-11-17T15:49:06Z (GMT) No. of bitstreams: 1 Tese Altino FINAL.pdf: 2068616 bytes, checksum: 27b47608fca03277f32d911d7ca60c1b (MD5) / Made available in DSpace on 2017-11-17T15:49:06Z (GMT). No. of bitstreams: 1 Tese Altino FINAL.pdf: 2068616 bytes, checksum: 27b47608fca03277f32d911d7ca60c1b (MD5) / A utilização da cocaína diretamente nas mucosas, por via oral, respiratória ou intravenosa, caracteriza-se por apresentar efeitos diretos sobre as estruturas da boca, mucosa, dentes e língua. Objetivos: Descrever as condições de saúde bucal da população usuária de cocaína e/ou crack, de 4 áreas do município de Salvador/BA, em relação à presença de cárie dentária, doença periodontal, sinais e sintomas de DTM; descrever os aspectos sociodemográficos e discutir a importância da atenção à saúde bucal neste grupo específico da população. Método: Análise descritiva e exploratória em 143 usuários de cocaína e/ou crack, sendo 85,31% do sexo masculino, com idade média de 33,27 anos, segundo características sociodemográficas, biológicas gerais e de saúde bucal, consumo de drogas e hábitos dietéticos, através de questionário e exame clínico intrabucal. Resultados: Indicaram baixo nível sociodemográfico, alto consumo de açúcar, índice CPOD 12,27 (DP=7,24), a condição periodontal foi avaliada com os índices CPI e PIP, demonstrando a alta prevalência de dentes excluídos e presença de cálculo. 74,13% apresentaram cinco ou mais sinais e sintomas de DTM. A análise multivariada relativa à ocorrência de DTM demonstrou que homens com mais de 35 anos e frequência de uso de tabaco e álcool, 2 ou mais vezes por semana, apresentaram significância para maior severidade de DTM (p <0,05). Conclusões: Os usuários apresentaram baixo nível socioeconômico e educacional, inadequada saúde bucal, altos índices de cárie, doença periodontal e sinais e sintomas de DTM. O Cirurgião-Dentista assume uma importante função na reabilitação destes pacientes, não apenas no tratamento em si, eliminando a dor e o desconforto, como também, contribuindo para aumentar a autoestima e favorecendo a inclusão social. / The use of cocaine directly in the mucosa, orally, respiratory or intravenous, is characterized by having direct effects on the structures of the mouth, mucosa, teeth and tongue. Objectives: To describe the oral health conditions of cocaine and / or crack users in 4 areas of the city of Salvador / BA, in relation to the presence of dental caries, periodontal disease, TMD signs and symptoms; Describe sociodemographic aspects and discuss the importance of oral health care in this specific group of the population. Method: Descriptive and exploratory analysis of 143 cocaine and / or crack users, 85.31% male, with a mean age of 33.27 years, according to sociodemographic, general biological and oral health characteristics, drug use and habits diet, through a questionnaire and intrabuccal clinical examination. Results: They indicated low sociodemographic level, high sugar consumption, the CPOD index was 12.27 (SD = 7.24), periodontal condition was evaluated with CPI and PIP indexes, demonstrating the high prevalence of excluded teeth and presence of calculus. 74.13% had five or more TMD signs and symptoms. The multivariate analysis of the occurrence of TMD showed that men over 35 years of age and alcohol and tobacco use frequency 2 or more times per week presented significance for greater TMD severity (p <0.05). CONCLUSIONS: Users presented low socioeconomic and educational level, inadequate oral health, high caries levels, periodontal disease and signs and symptoms of TMD. The Dentist plays an important role in the rehabilitation of these patients, not only in the treatment itself, eliminating pain and discomfort, but also contributing to increase selfesteem and favoring social inclusion
9

Přesnost měření pomocí zařízení pro sběr dat pro GIS s možným využitím v pozemkových úpravách / Accuracy of measurement using devices for data collection for GIS with the possible use in land consolidation

CIMBALA, Michal January 2013 (has links)
The aim of my thesis was describe a clear form to present the possibilities of facilities for the collection of GIS data for the possible use in land consolidation. My purpose was to accurately determine what the potential cost of purchase and processing of data and how accurately we are able to process this data. Next I have dealt with quality data that we can get from organizations that work with data. I also dealt with the design of land consolidation method using a digital terrain model (DTM). This method could bring a lot of innovation in solving problems in land consolidation in the future
10

Smooth Path Planning Using Splines For Unmanned Planetary Vehicles

January 2013 (has links)
abstract: One of the main challenges in planetary robotics is to traverse the shortest path through a set of waypoints. The shortest distance between any two waypoints is a direct linear traversal. Often times, there are physical restrictions that prevent a rover form traversing straight to a waypoint. Thus, knowledge of the terrain is needed prior to traversal. The Digital Terrain Model (DTM) provides information about the terrain along with waypoints for the rover to traverse. However, traversing a set of waypoints linearly is burdensome, as the rovers would constantly need to modify their orientation as they successively approach waypoints. Although there are various solutions to this problem, this research paper proposes the smooth traversability of the rover using splines as a quick and easy implementation to traverse a set of waypoints. In addition, a rover was used to compare the smoothness of the linear traversal along with the spline interpolations. The data collected illustrated that spline traversals had a less rate of change in the velocity over time, indicating that the rover performed smoother than with linear paths. / Dissertation/Thesis / M.S. Computer Science 2013

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