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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.
11

Uma abordagem para visualização e análise baseada em clustering de dados espaço-temporais. / An approach to visualization and analysis based on clustering of spatiotemporal data.

OLIVEIRA, Maxwell Guimarães de. 04 August 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-08-04T13:59:37Z No. of bitstreams: 1 MAXWELL GUIMARÃES DE OLIVEIRA - DISSERTAÇÃO PPGCC 2012..pdf: 28277196 bytes, checksum: 398cd7b385ee61c414d0086810fbeeed (MD5) / Made available in DSpace on 2018-08-04T13:59:37Z (GMT). No. of bitstreams: 1 MAXWELL GUIMARÃES DE OLIVEIRA - DISSERTAÇÃO PPGCC 2012..pdf: 28277196 bytes, checksum: 398cd7b385ee61c414d0086810fbeeed (MD5) Previous issue date: 2012-08-20 / Capes / Atualmente, há um volume considerável de dados espaço-temporais disponíveis em vários meios, sobretudo na Internet. A visualização de dados espaço-temporais é uma tarefa complexa, que requer uma série de recursos visuais apropriados para que, em conjunto, possam permitir aos usuários uma correta interpretação das informações analisadas. Além do emprego de técnicas de visualização, a utilização de técnicas de descoberta de conhecimento em bancos de dados tem se mostrado relevante no auxílio à análise exploratória de relacionamentos em dados espaço-temporais. O levantamento do estado da arte em visualização de dados espaço-temporais leva à conclusão de que a área ainda é deficiente em soluções para visualização e análise desses tipos. Muitas abordagens abrangem somente questões espaciais, desprezando as características temporais desses dados. Inserido nesse contexto, o principal objetivo deste trabalho é melhorar a experiência do usuário em visualização e análise espaço-temporal, indo além do universo da visualização dos dados espaço-temporais brutos e considerando, também, a importância em visualização de dados espaço-temporais derivados de um processo de descoberta de conhecimento, mais especificamente algoritmos de clustering. Esse objetivo é atingido com a definição de uma abordagem inovadora em visualização de dados espaço-temporais, e de sua implementação, denominada GeoSTAT (Geographic SpatioTemporal Analysis Tool), que engloba pontos importantes observados nas principais abordagens existentes e acrescenta, principalmente, técnicas de visualização voltadas à dimensão temporal e à utilização de algoritmos de clustering, valorizando características até então pouco exploradas em dados espaço-temporais. A validação deste trabalho ocorre por meio de dois estudos de caso, onde cada um aborda dados espaço-temporais de um domínio específico, para demonstrar a experiência do usuário final diante das técnicas de visualização reunidas na abordagem proposta. / Nowadays, there is a considerable amount of spatiotemporal data available in various media, especially on the Internet. The visualization of spatiotemporal data is a complex task that requires a series of visual suitable resources which can enable users to have a correct interpretation of the data. Apart from the use of visualization techniques, the use of techniques of knowledge discovery in databases has proven relevantfor the exploratory analysis of relationships in spatiotemporal data. The state of the art in visualization of spatiotemporal data leads to the conclusion that the area is still deficient in solutions for viewing and analysis of those data. Many approaches cover only spatial issues, ignoring the temporal characteristics of such data. Inserted in this context, the main objective of this work is to improve the user experience in spatiotemporal visualization and analysis, going beyond the universe of visualization of spatiotemporal raw data and also considering the importance of visualization of spatiotemporal data derived from a knowledge discovery process, more specifically clustering algorithms. This goal is achieved by defining an innovative approach for the analysis and visualization of spatiotemporal data, and its implementation, called GeoSTAT (Spatiotemporal Geographic Analysis Tool), which includes importam points in the main existing approaches and adds especially visualization techniques geared to the temporal dimension and the use of clustering algorithms, enhancing unexplored features in spatiotemporal data. The validation of this work occurs through two case studies, where each one deals with spatiotemporal data of a specific domain to demonstrate the end-user experience on the visualization techniques combined in the proposed approach.
12

Approche ontologique pour la modélisation et le raisonnement sur les trajectoires : prise en compte des aspects thématiques, temporels et spatiaux / Ontological approach for modeling and reasoning about trajectories : taking into account the thematics, temporals and spatials aspects

Mefteh, Wafa 20 September 2013 (has links)
L’évolution des systèmes de capture des données concernant les objets mobiles a donné naissance à de nouvelles générations d’applications dans différents domaines. Les données capturées, communément appelées « trajectoires », sont au cœur des applications qui analysent et supervisent le trafic routier, maritime et aérien ou également celles qui optimisent le transport public. Elles sont aussi exploitées dans les domaines du jeu vidéo, du cinéma, du sport et dans le domaine de la biologie animale pour l’étude des comportements, par les systèmes de capture des mouvements. Aujourd’hui, les données produites par ces capteurs sont des données brutes à caractère spatio-temporel qui cachent des informations sémantiquement riches et enrichissantes pour un expert. L’objectif de cette thèse est d’associer automatiquement aux données spatio-temporelles des descriptions ou des concepts liés au comportement des objets mobiles, interprétables par les humains, mais surtout par les machines. Partant de ce constat, nous proposons un processus partant de l’expérience des objets mobiles de monde réel, notamment le bateau et l’avion, vers un modèle ontologique générique pour la trajectoire. Nous présentons quelques requêtes qui intéressent les experts du domaine et qui montrent l’impossibilité d’exploiter les trajectoires dans leurs états bruts. En effet, l’analyse de ces requêtes fait ressortir trois types de composantes sémantiques : thématique, spatiale et temporelle. Ces composantes doivent être rattachées aux données des trajectoires ce qui conduit à introduire un processus d’annotation qui transforme les trajectoires brutes en trajectoires sémantiques. Pour exploiter les trajectoires sémantiques, on construit une ontologie de haut niveau pour le domaine de la trajectoire qui modélise les données brutes et leurs annotations. Vu le besoin d’un raisonnement complet avec des concepts et des opérateurs spatiaux et temporaux, nous proposons la solution de réutilisation des ontologies de temps et d’espace. Dans cette thèse, nous présentons aussi notre travail issu d’une collaboration avec une équipe de recherche qui s’intéresse à l’analyse et à la compréhension des comportements des mammifères marins dans leur milieu naturel. Nous détaillons le processus utilisé dans les deux premiers domaines, qui part des données brutes représentant les déplacements des phoques jusqu’au modèle ontologique de trajectoire des phoques. Nous accordons une attention particulière à l’apport de l’ontologie de haut niveau définissant un cadre contextuel pour l’ontologie du domaine d’application. Enfin, cette thèse présente la difficulté de mise en œuvre sur des données de taille réelle (des centaines de milliers d’individus) lors du raisonnement à travers les mécanismes d’inférence utilisant des règles métiers. / The evolution of systems capture data on moving objects has given birth to new generations of applications in various fields. Captured data, commonly called ”trajectories”, are at the heart of applications that analyze and monitor road, maritime and air traffic or also those that optimize public transport. They are also used in the video game, movies, sports and field biology to study animal behavior, by motion capture systems. Today, the data produced by these sensors are raw spatio-temporal characters hiding semantically rich and meaningful informations to an expert data. So, the objective of this thesis is to automatically associate the spatio-temporal data descriptions or concepts related to the behavior of moving objects, interpreted by humans, but also by machines. Based on this observation, we propose a process based on the experience of real-world moving objects, including vessel and plane, to an ontological model for the generic path. We present some applications of interest to experts in the field and show the inability to use the paths in their raw state. Indeed, the analysis of these queries identified three types of semantic components : thematic, spatial and temporal. These components must be attached to data paths leading to enter an annotation that transforms raw semantic paths process trajectories. To exploit the semantic trajectories, we construct a high-level ontology for the domain of the path which models the raw data and their annotations. Given the need of complete reasoning with concepts and spatial and temporal operators, we propose the solution for reuse of ontologies time space. In this thesis, we also present our results from a collaboration with a research team that focuses on the analysis and understanding of the behavior of marine mammals in their natural environment. We describe the process used in the first two areas, which share raw data representing the movement of seals to ontological trajectory model seals. We pay particular attention to the contribution of the upper ontology defined in a contextual framework for ontology application. Finally, this thesis presents the difficulty of implementation on real data size (hundreds of thousands) when reasoning through inference mechanisms using business rules.
13

Visual analytics for detection and assessment of process-related patterns in geoscientific spatiotemporal data

Köthur, Patrick 04 January 2016 (has links)
Diese Arbeit untersucht, inwiefern Visual Analytics die Analyse von Prozessen in geowissenschaftlichen raum-zeitlichen Daten unterstützen kann. Hierzu wurden drei neuartige Visual Analytics Ansätze entwickelt. Jeder Ansatz addressiert eine wichtige Analyseperspektive. Der erste Ansatz erlaubt es, wichtige räumliche Zustände in den Daten sowie deren auftreten in der Zeit zu untersuchen. Mittels hierarchischem Clustering werden alle in den Daten enthaltenen räumlichen Zustände in einer Clusterhierarchie verortet. Interaktive visuelle Analyse ermöglicht es, verschiedene räumliche Zustände aus den Daten zu extrahieren und die dazugehörigen raum-zeitlichen Muster zu interpretieren und zu bewerten. Der zweite Ansatz unterstützt die systematische Analyse des in den Daten zu beobachtenden zeitlichen Verhaltens sowie dessen Auftreten im geographischen Raum mittels einer Kombination aus Cluster Ensembles und interaktiver visueller Exploration. Der dritte Ansatz gestattet die Detektion und Analyse von zeitlichen Zusammenhängen in den Daten. Hierzu wurde eine etablierte Methode zur Analyse von zeitlichen Zusammenhängen zwischen zwei einzelnen Zeitreihen, gefensterte Kreuzkorrelation, durch Visual Analytics auf den Vergleich von Zeitreihenensembles erweitert. Dadurch ist es nicht nur möglich, Zusammenhänge zwischen Zeitreihen zu untersuchen, sondern auch Unsicherheiten in den Daten zu berücksichtigen. Alle Ansätze wurden anhand einer nutzer- und aufgabenorientierten Methodik entwickelt und erfolgreich in Anwendungsfällen aus der Erdsystem-Modellierung, der Ozeanmodellierung, der Paläoklimatologie und sogar den Kognitionswissenschaften eingesetzt. Diese Dissertation zeigt, dass Visual Analytics einen wertvollen Ansatz zur Analyse von Prozess-bezogenen Mustern in raum-zeitlichen Daten darstellt. Es kann die Grenzen existierender Analysemethoden erweitern und ermöglicht Geowissenschaftlern neue, aufschlussreiche Sichtweisen auf Daten und die darin beschriebenen Prozesse. / This thesis studied how visual analytics can facilitate the analysis of processes in geoscientific spatiotemporal data. Three novel visual analytics solutions were developed, each addressing an important analysis perspective. The first solution addresses the analysis of prominent spatial situations in the data and their occurrence over time. Hierarchical clustering is used to arrange all spatial situations in the data in a hierarchy of clusters. The combination with interactive visual analysis enables geoscientists to explore and alter the resulting hierarchy, to extract different sets of representative spatial situations, and to interpret and assess the corresponding spatiotemporal patterns. The second solution supports geoscientists in the analysis of prominent types of temporal behavior and their location in geographic space. Cluster ensembles are integrated with interactive visual exploration to enable users to systematically detect and interpret various types of temporal behavior in different data sets and to use this information for assessment of simulation model output. The third solution enables geoscientists to detect and analyze interrelations of temporal behavior in the data. Windowed cross-correlation, a technique for comparison of two individual time series, was extended to the comparison of entire ensembles of time series through visual analytics. This not only allows scientists to study interrelations, but also to assess how much these interrelations vary between two ensembles. All visual analytics solutions were developed following a rigorous user- and task-centered methodology and successfully applied to use cases in Earth system modeling, ocean modeling, paleoclimatology, and even cognitive science. The results of this thesis demonstrate that visual analytics successfully addresses important analysis perspectives and that it is a valuable approach to the analysis of process-related patterns in geoscientific spatiotemporal data.

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