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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

Organização e armazenamento de imagens multitemporais georreferenciadas para suporte ao processo de detecção de mudanças /

Souza, Luiz Eduardo Christovam de January 2018 (has links)
Orientador: Maria de Lourdes Bueno Trindade Galo / Resumo: Atualmente o volume de dados produzidos tem atingido patamares nunca imaginados, sobretudo em decorrência da multiplicação do número de sensores e da popularização da internet, com a web 2.0 e as redes sociais. Dentre os diversos tipos de sensores existentes, os de imageamento, transportados principalmente por satélites, produzem vastos conjuntos de observações da superfície da Terra. A observação contínua da Terra por satélites possibilita o monitoramento de mudanças no uso e cobertura da terra. Contudo, em diversas pesquisas relacionadas a mudanças no planeta, são utilizados apenas pequenos fragmentos do imenso conjunto de dados existente, essencialmente devido a ainda haver uma lacuna científicatecnológica relacionada aos procedimentos de organização, armazenamento, análise e representação de grandes conjuntos de dados. Portanto, nessa pesquisa foi definida uma estrutura para organização, armazenamento e recuperação de dados espaço-temporais, com o propósito de fornecer suporte a detecção de mudanças na cobertura da terra. Para tanto, foi definida como aplicação a análise de séries temporais de Normalized Difference Vegetation Index (NDVI) derivadas de imagens adquiridas desde 1984 até 2017, pelos sensores Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+) e Operational Land Imager (OLI) para a região de Porto Velho, Rondônia. Foi construída uma série temporal de NDVI para a posição de cada pixel presente na área de estudo. Regiões de referência foram definidas par... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Nowadays the size of datasets has been reaching levels never seen before, mainly due to new sensors and the widespread of the internet, with web 2.0 and social media. Among the various types of sensors, the imaging sensors, mainly carried by satellites, have produced big Earth observations datasets. The regular Earth observation by satellites enable to monitor Land Use/Cover Change (LUCC). However, in many researches related to LUCC, only small parts of the big Earth Observation datasets are normally used, because there is still a scientifictechnological gap related to the organization, storage, analysis and representation of big Earth Observations data. Therefore, in this research was defined a database for the organization, storage and retrieval of spatio-temporal data, to support a LUCC task. Therefore, the time series analysis of Normalized Difference Vegetation Index (NDVI) of images acquired from 1984 to 2017 by Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+) and Operational Land Imager (OLI) for the region of Porto Velho, Rondônia was defined as the application. To the position each of the pixel in the study area was built a NDVI time series. Reference areas were defined to retrieve reference time series that describe the land cover types and the change classes (anthropic and natural). The Fast Dynamic Time Warping (FastDTW) algorithm was used to measure the similarity between the time series, to be classified and reference ones. To find the time series clas... (Complete abstract click electronic access below) / Mestre
2

Medical Data Management on the cloud / Gestion de données médicales sur le cloud

Mohamad, Baraa 23 June 2015 (has links)
Résumé indisponible / Medical data management has become a real challenge due to the emergence of new imaging technologies providing high image resolutions.This thesis focuses in particular on the management of DICOM files. DICOM is one of the most important medical standards. DICOM files have special data format where one file may contain regular data, multimedia data and services. These files are extremely heterogeneous (the schema of a file cannot be predicted) and have large data sizes. The characteristics of DICOM files added to the requirements of medical data management in general – in term of availability and accessibility- have led us to construct our research question as follows:Is it possible to build a system that: (1) is highly available, (2) supports any medical images (different specialties, modalities and physicians’ practices), (3) enables to store extremely huge/ever increasing data, (4) provides expressive accesses and (5) is cost-effective .In order to answer this question we have built a hybrid (row-column) cloud-enabled storage system. The idea of this solution is to disperse DICOM attributes thoughtfully, depending on their characteristics, over both data layouts in a way that provides the best of row-oriented and column-oriented storage models in one system. All with exploiting the interesting features of the cloud that enables us to ensure the availability and portability of medical data. Storing data on such hybrid data layout opens the door for a second research question, how to process queries efficiently over this hybrid data storage with enabling new and more efficient query plansThe originality of our proposal comes from the fact that there is currently no system that stores data in such hybrid storage (i.e. an attribute is either on row-oriented database or on column-oriented one and a given query could interrogate both storage models at the same time) and studies query processing over it.The experimental prototypes implemented in this thesis show interesting results and opens the door for multiple optimizations and research questions.
3

Hybride Datenbankarchitekturen am Beispiel der neuen SAP In-Memory-Technologie

Färber, Franz, Jäcksch, Bernhard, Lemke, Christian, Grpße, Philipp, Lehner, Wolfgang 20 January 2023 (has links)
Die Verfügbarkeit neuer Technologien wie Multi-Core, SSD oder große Hauptspeicherkapazitäten bieten eine Gelegenheit, die klassischen Architekturansätze von Datenbanksystemen zu überdenken und an bestimmten Stellen zu korrigieren. In diesem Beitrag stellen wir die Grobstruktur der neuen hauptspeicherzentrierten SAP Technologie als einen Ansatz einer kommerziellen Umsetzung moderner Architekturkonzepte vor. Zentrales Design-Kriterium ist dabei ein hybrider Ansatz, um eine möglichst hohe Anzahl von Anforderungsvarianten optimal zu unterstützen. Nach einer Einleitung führt der Artikel durch die wichtigsten Architekturkomponenten und illustriert den grundsätzlichen Aufbau des Systems. Für einen „deep dive“ werden zwei Bereiche in Teil 3 und 4 des Artikels im Detail diskutiert. Dabei greift der Artikel zum einen den Aspekt der physischen Optimierung im Kontext eines hauptspeicherzentrierten Systems auf und diskutiert unterschiedliche Komprimierungs- und Sortierungskriterien, wie sie im klassischen disk-zentrierten Ansatz nicht zu finden sind. Zum anderen wird die Unterstützung von Planungsanwendungen skizziert, wodurch ein Einblick in die spezifische Unterstützung einer Anwendungsdomäne („business planning“) und die prinzipiellen Erweiterungen für komplexe Operationen zur direkten Unterstützung von darauf aufbauender Planungsfunktionalität gezeigt werden.

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