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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

Influence de la tâche sur l'élaboration de stratégies visuelles dans la schizophrénie / Visual scanning in schizophrenia

Delerue, Céline 17 December 2010 (has links)
Les patients schizophrènes présentent une sensibilité exacerbée aux distracteurs dans tout l’environnement spatial. Paradoxalement, les études sur l’exploration visuelle avec enregistrement des mouvements oculaires, menées chez les patients schizophrènes, font état d’un profil d’exploration réduit des visages, des paysages, et des images non significatives. La majorité des études réalisées chez ces patients ont été réalisée en condition d’exploration passive (sans instructions) ou lors de la reconnaissance de l’expression faciale. Chez les sujets sains, deux principaux facteurs affectent l’orientation de l’attention : (1) les caractéristiques saillantes (stimulus-driven) de l’image, et (2) les objectifs de l’individu (goal-driven). En effet, les études menées chez les individus sains ont démontré que la capture automatique de l’attention par un distracteur peut être contrôlée lorsque l’attention est focalisée sur une tâche. De plus, des anomalies dans la coordination de séquences d’actions ont été rapportées dans la schizophrénie. Des études ont enregistré les mouvements des yeux de sujets sains pendant la réalisation d’une action (préparer un sandwich). Ces études ont montré que (1) la chronologie des mouvements oculaires suit la chronologie des actions nécessaires pour réaliser la tâche, et (2) l’exploration visuelle est insensible aux objets non pertinents de la scène. Notre objectif est d’examiner si les personnes souffrant de schizophrénie sont capables de contrôler l’orientation spatiale de l’attention au cours de situations impliquant différents degrés de complexité : (1) exploration passive (sans instructions, l’exploration est libre), et (2) exploration active (l’exploration est contrainte par la réalisation d’une tâche). Dans un premier temps, nos études portent sur la comparaison de l’exploration visuelle en condition passive (free viewing) et active (avec une tâche à réaliser) sur des visages. Dans un second temps, nous avons comparé l’exploration visuelle dans des situations d’intention d’action ou d’identification d’action sur des objets ou des personnages exécutant une action. Enfin, dans un troisième temps, les patients et les sujets sains ont été placés dans une situation naturelle avec réalisation d’une action avec des objets familiers ou non familiers. Nos études ont montré une exploration visuelle réduite des patients schizophrènes en condition d’exploration passive, et une amélioration de ce profil d’exploration lorsque les patients sont focalisés sur une tâche. Cependant, les patients présentaient des différences dans leurs stratégies d’exploration par rapport aux sujets sains. / Patients with schizophrenia present a perceptual distractibility in spatial environment. Paradoxically, studies monitoring eye movements, in patients with schizophrenia, show reduced visual scan paths on photographs of faces, landscapes, and meaningless images. In most of the previous studies in schizophrenia, visual scanning has been examined under passive viewing conditions, and for some of them, participants were asked to determine the facial expression. In healthy participants, two main factors affect the orientation of attention: (1) the stimulus-driven, and (2) the goal-driven. Indeed, studies in healthy participants have demonstrated that automatic attention on a distractor can be controlled when attention is focused on a task. Moreover, patients with schizophrenia present an action planning disorganization. Studies have recorded healthy participants’ eye movements during the making of an action (to make a sandwich). These studies have shown that the chronology of eye movements follows the chronology of necessary actions to realize the task, and (2) the visual scanning is independent of irrelevant objects in the scene. This thesis was designed to examine whether patients with schizophrenia are able to control the spatial orientation of their attention during situations implying various degrees of complexity: (1) free viewing, and (2) active viewing (with a task to accomplish). First of all, visual scan paths in a free viewing condition were compared with active viewing conditions on face images. Secondly, we have compared visual scanning in action intention or action identification situations on object images or pictures presenting a character accomplishing an action. Finally, patients with schizophrenia and healthy participants had to make an natural task with familiar or unfamiliar objects. Our studies have shown a restricted visual scanning of patients with schizophrenia in free viewing condition, and an improvement of this pattern when patients realize a task. However, patients with schizophrenia presented different visual strategies compared to healthy participants.
2

Recuperação de informação com realimentação de relevância apoiada em visualização / Information retrieval with relevance feedback on supported display

Melo, Diogo Oliveira de 16 April 2014 (has links)
A mineração de grandes coleções de textos, imagens e outros tipos de documentos tem se mostrado uma forma efetiva para exploração e interação com grandes quantidades de informações disponíveis, principalmente na World Wide Web. Neste contexto, diversos trabalhos têm tratado de mineração tanto de coleções estáticas quanto de coleções dinâmicas de objetos. Adicionalmente, técnicas de visualização têm sido propostas para auxiliar o processo de entendimento e de exploração dessas coleções, permitindo que a interação do usuário melhore o processo de mineração (user in the loop). No caso específico de dados dinâmicos, foi desenvolvido por Roberto Pinho e colegas uma técnica incremental (IncBoard) com o objetivo de visualizar coleções dinâmicas de elementos. Tal técnica posiciona os elementos em um grid bidimensional baseado na similaridade de conteúdo entre os elementos. Procura-se manter elementos similares próximos no grid. A técnica foi avaliada em um processo que simulava a chegada de novos dados, apresentando iterativamente novos elementos a serem posicionados no mapa corrente. Observa-se, entretanto, que um aspecto importante de tal ferramenta seria a possibilidade de novos elementos - a serem exibidos no mapa, mantendo coerência com o mapa corrente - serem selecionados a partir do interesse demonstrado pelo usuário. Realimentação de relevância tem se mostrado muito efetiva na melhoria da acurácia do processo de recuperação. Entretanto, um problema ainda em aberto é como utilizar técnicas de realimentação de relevância em conjunto com exploração visual no processo de recuperação de informação. Neste trabalho, é investigado o desenvolvimento de técnicas de exploração visual utilizando realimentação de relevância para sistemas de recuperação de informação de domínio específico. O Amuzi, um sistema de busca de músicas, foi desenvolvido como uma prova de conceito para a abordagem investigada. Dados coletados da utilização do Amuzi, por usuários, sugerem que a combinação de tais técnicas oferece vantagens, quando utilizadas em determinados domínios. Nesta dissertação, a recuperação de informação com realimentação de relevância apoiada em visualização, bem como o sistema Amuzi são descritos. Também são analisados os registros de utilização dos usuários / The mining of large text collections, images and other types of digital objects has shown to be a very effective way to explore and interact with big data, specially on the World Wide Web. On that subject, many researchers have been done on data mining of static and dynamic collections. Moreover, data visualization techniques have been proposed to aid on the understanding and exploration of such data collections, also allowing users to interact with data, user in the loop. On the speciific subject of dynamic data, Roberto Pinho and colleagues have developed an incremental technique, called Inc-Board, which aims to visualize dynamic data collections. IncBoard displays the documents on a two dimensional grid in a way that similar elements tends to be close to each other. This technique was evaluated in a process that simulated the arrival of new data elements, iteratively inserting new elements on the grid. Nonetheless, it would be useful if the user could interact with such documents to point out which are relevant and which are not relevant to his/her search. Relevance Feedback has also shown to be effective on improving the accuracy of Information Retrieval techniques. An issue that still open is how to combine data visualization and Relevance Feedback to improve Information Retrieval. On this dissertation, the development of techniques with data visualization and Relevance Feedback are investigated to aid on the Information Retrieval task, for specific domains. Amuzi is an Information Retrieval system, built to be a proof of concept for the investigated approach. Data collected from the usage of the system suggests that combining such techniques may outperform traditional Information Retrieval systems when applied for specifc domains. This dissertation has the description the information retrieval process with feedback relevance supported by visualization and the Amuzi system. Usage log are processed and analyzed to evaluate the investigated approach
3

Recuperação de informação com realimentação de relevância apoiada em visualização / Information retrieval with relevance feedback on supported display

Diogo Oliveira de Melo 16 April 2014 (has links)
A mineração de grandes coleções de textos, imagens e outros tipos de documentos tem se mostrado uma forma efetiva para exploração e interação com grandes quantidades de informações disponíveis, principalmente na World Wide Web. Neste contexto, diversos trabalhos têm tratado de mineração tanto de coleções estáticas quanto de coleções dinâmicas de objetos. Adicionalmente, técnicas de visualização têm sido propostas para auxiliar o processo de entendimento e de exploração dessas coleções, permitindo que a interação do usuário melhore o processo de mineração (user in the loop). No caso específico de dados dinâmicos, foi desenvolvido por Roberto Pinho e colegas uma técnica incremental (IncBoard) com o objetivo de visualizar coleções dinâmicas de elementos. Tal técnica posiciona os elementos em um grid bidimensional baseado na similaridade de conteúdo entre os elementos. Procura-se manter elementos similares próximos no grid. A técnica foi avaliada em um processo que simulava a chegada de novos dados, apresentando iterativamente novos elementos a serem posicionados no mapa corrente. Observa-se, entretanto, que um aspecto importante de tal ferramenta seria a possibilidade de novos elementos - a serem exibidos no mapa, mantendo coerência com o mapa corrente - serem selecionados a partir do interesse demonstrado pelo usuário. Realimentação de relevância tem se mostrado muito efetiva na melhoria da acurácia do processo de recuperação. Entretanto, um problema ainda em aberto é como utilizar técnicas de realimentação de relevância em conjunto com exploração visual no processo de recuperação de informação. Neste trabalho, é investigado o desenvolvimento de técnicas de exploração visual utilizando realimentação de relevância para sistemas de recuperação de informação de domínio específico. O Amuzi, um sistema de busca de músicas, foi desenvolvido como uma prova de conceito para a abordagem investigada. Dados coletados da utilização do Amuzi, por usuários, sugerem que a combinação de tais técnicas oferece vantagens, quando utilizadas em determinados domínios. Nesta dissertação, a recuperação de informação com realimentação de relevância apoiada em visualização, bem como o sistema Amuzi são descritos. Também são analisados os registros de utilização dos usuários / The mining of large text collections, images and other types of digital objects has shown to be a very effective way to explore and interact with big data, specially on the World Wide Web. On that subject, many researchers have been done on data mining of static and dynamic collections. Moreover, data visualization techniques have been proposed to aid on the understanding and exploration of such data collections, also allowing users to interact with data, user in the loop. On the speciific subject of dynamic data, Roberto Pinho and colleagues have developed an incremental technique, called Inc-Board, which aims to visualize dynamic data collections. IncBoard displays the documents on a two dimensional grid in a way that similar elements tends to be close to each other. This technique was evaluated in a process that simulated the arrival of new data elements, iteratively inserting new elements on the grid. Nonetheless, it would be useful if the user could interact with such documents to point out which are relevant and which are not relevant to his/her search. Relevance Feedback has also shown to be effective on improving the accuracy of Information Retrieval techniques. An issue that still open is how to combine data visualization and Relevance Feedback to improve Information Retrieval. On this dissertation, the development of techniques with data visualization and Relevance Feedback are investigated to aid on the Information Retrieval task, for specific domains. Amuzi is an Information Retrieval system, built to be a proof of concept for the investigated approach. Data collected from the usage of the system suggests that combining such techniques may outperform traditional Information Retrieval systems when applied for specifc domains. This dissertation has the description the information retrieval process with feedback relevance supported by visualization and the Amuzi system. Usage log are processed and analyzed to evaluate the investigated approach
4

Visual Analysis of Engineers' Biographies and Engineering Branches

Meinecke, Christofer, Jänicke, Stefan 25 January 2019 (has links)
The Prosopographic Database of German Engineers 1825–1970 contains a multitude of biographical information. Given a set of research interests by collaborating historians, this paper discusses the steps undertaken (1) to extract engineering subjects from unstructured text entries in the database accompanied with geospatial and temporal information, (2) to adapt existing visual representations to facilitate exploratory analyses, and (3) to design a visual interface to support the interactive composition of engineering branches from engineering subjects to enable the comparative analysis of geospatial-temporal developments in engineering. Usage scenarios outline the benefit of the proposed visualizations for modern prosopography research.
5

Visual Exploration and Comparative Analytics of Multidimensional Data Sets

Liu, Xiaotong 28 December 2016 (has links)
No description available.
6

Direktionaler Bias der initialen visuellen Exploration

Trottenberg, Thomas 25 January 2002 (has links)
In der vorliegenden Arbeit wurde das spontane visuelle Explorationsverhalten von 31 Patienten mit einem idiopathischen Parkinson-Syndrom und von 17 gesunden Kontrollpersonen aus der gleichen Altersgruppe systematisch untersucht. Die Analyse der initialen visuellen Exploration (IVE) wurde mit Hilfe von Texturvorlagen durchgeführt, die aus Elementen der Texton-Forschung aufgebaut waren und die einen attentiven okulomotorischen Suchvorgang voraussetzten. Da ein Teil der Vorlagen differente Zielelemente in der linken und rechten Hälfte beinhaltete, konnte aus den Antworten der Versuchspersonen über das zuerst entdeckte Zielelement, auf die Seite der initialen Exploration geschlossen werden. In einer vorherigen Studie konnte gezeigt werden, dass die Mehrzahl der Normalpersonen ihre Exploration in der linken Hälfte der Vorlagen beginnt, während die meisten Neglect-Patienten mit rechtshemisphäralen Läsionen auf der rechten Seite anfangen. Standarduntersuchungen auf Neglect-Symptome (Linienteilungstest, Ausstreichtest, doppelseitige simultane Stimulation) wurden bei unseren Versuchspersonen als Referenztests ebenfalls durchgeführt. Bei der IVE-Aufgabe starteten 65 Prozent der gesunden Kontrollpersonen und 64 Prozent der Parkinson-Patienten mit überwiegender Beeinträchtigung der rechten Körperhälfte (RPD) und linkshemisphäral betontem Dopamindefizit den Suchvorgang erwartungsgemäß auf der linken Seite des Texturenfeldes. Im Gegensatz zu dieser Verteilung zeigten nur 12 Prozent der Parkinson-Patienten mit vornehmlicher linksseitiger Beteiligung (LPD) eine linksgerichtete IVE, während der Rest keine (35%) bzw. eine rechtsseitige (53%) Bevorzugung bei der initialen Exploration aufwies, die damit IVE-Veränderungen bei Neglect-Patienten glich. Die Ergebnisse der Referenztests ergaben bei keiner Untersuchungsgruppe einen Hinweis auf eine spatiale Vernachlässigung. Das atypische Explorationsverhalten der vornehmlich linksbetroffenen Parkinsongruppe sollte im Zusammenhang mit jüngst entwickelten Konzepten zur Aufmerksamkeitsregulation interpretiert werden, welche eine frühe automatische Orientierung in Richtung des ipsiläsionalen Halbraumes als milde Neglect-Manifestation bzw. als Residualzustand nach einem Hemineglect ansehen. Da dieser subtile Orientierungsvorzug, verglichen mit schwereren und offensichtlicheren klinischen Symptomen des Neglects, weniger einem Kompensationsmechanismus unterliegt, ist die Sensitivität der IVE-Untersuchung bei Patienten mit einem aus chronischen Störungen resultierenden subklinischen Neglect höher, als die der konventionellen Tests. Die vorliegenden Ergebnisse steuern dem komplexen Bild der kognitiven und visuospatialen Veränderungen bei Parkinson-Patienten wichtige neue Aspekte bei. Des weiteren ergänzen unsere Resultate das bisherige Wissen über Neglect-Mechanismen sowie über die Rolle dopaminerger Transmittersysteme bei der Regulation von Aufmerksamkeit. Über dies ermutigen die vorliegenden Ergebnisse zu systematischen Untersuchungen von Effekten dopaminerger Medikamente auf Neglect-Phänomene. / In the present study side preferences in spontaneous visual exploration were assessed systematically in 31 patients with idiopathic Parkinson's disease and 17 age-matched controls. The analysis of the initial visual exploration (IVE) was based on the exploration of texture-arrays derived from texton research requiring attentive oculomotor scanning. Since the left and right half of the arrays contained two different target-elements respectively the side of initial exploration could be deduced from the response of the subject which of the two target-elements was discovered at first. As shown in a previous study most healthy subjects exhibit a marked asymmetry of IVE with a strong left-sided bias when assessed by this paradigm while most neglect-patients with structural right hemispheric lesions initiate exploration in the right half of the arrays. Standard assessments for symptoms of neglect (i.e. line bisection, line cancellation and double simultaneous stimulation) were performed as reference tests in our patients. In the IVE-task 65 percent of normal controls and 64 percent of patients with predominant involvement of the right body half (RPD) started exploration expectedly on the left half of the arrays. In contrast to this distribution only 12 percent of patients with predominantly left-sided disease (LPD) showed a leftward IVE while the rest had an ambiguous (35%) or rightward (53%) directional bias for initial exploration and thus a behavior that corresponded to the IVE-abnormalities found in neglect-patients. The results of the reference-assessments did not reveal further signs of neglect in any of the patient-groups. The atypical IVE in patients with predominantly left-sided Parkinson's disease should be interpreted in the context of recent concepts of attention postulating that a bias in early spontaneous orientation directed to the ipsilesional hemifield reflects a mild and residual manifestation of hemineglect. Since this subtle orientational bias is less subject to compensation than more conspicuous clinical signs of neglect sensitivity is higher in IVE-testing than in conventional neglect-assessments in chronic disorders with subclinical neglect. The present findings contribute a new aspect to the complex picture of cognitive and visuospatial abnormalities in Parkinson's disease. Furthermore our results extend previous knowledge on the mechanisms of neglect and the role of dopamine in the mediation of attention. Additionally our results encourage systematic investigations on dopaminergic medication effects on neglect phenomena.
7

Scalable Visual Hierarchy Exploration

Stroe, Ionel Daniel 10 May 2000 (has links)
More and more modern computer applications, from business decision support to scientific data analysis, utilize visualization techniques to support exploratory activities. Various tools have been proposed in the past decade to help users better interpret data using such display techniques. However, most do not scale well with regard to the size of the dataset upon which they operate. In particular, the level of cluttering on the screen is typically unacceptable and the performance is poor. To solve the problem of cluttering at the interface level, visualization tools have recently been extended to support hierarchical views of the data, with support for focusing and drilling-down using interactive brushes. To solve the scalability problem, we now investigate how best to couple such a visualization tool with a database management system without losing the real-time characteristics. This integration must be done carefully, since visual user interactions implemented as main memory operations do not map directly into efficient database operations. The main efficiency issue when doing this integration is to avoid the recursive processing required for hierarchical data retrieval. For this problem, we have develop a tree labeling method, called MinMax tree, that allows the movement of the on-line recursive processing into an off-line precomputation step. Thus, at run time, the recursive processing operations translate into linear cost range queries. Secondly, we employ a main memory access strategy to support incremental loading of data into the main memory. The techniques have been incorporated into XmdvTool, a multidimensional visual exploration tool, in order to achieve scalability. The tool now successfully scales up to datasets of the order 10^5-10^7 records. Lastly, we report experimental results that illustrate the impact of the proposed techniques on the system's overall performance.
8

Percevoir l'interaction sociale dans le mouvement humain : études psychophysiologiques du développement typique et dans les troubles du spectre autistique / Perception of social interaction through human motion : psychophysiological studies in typical development and autism spectrum disorders

Roche, Laëtitia 06 December 2013 (has links)
L'interaction sociale représente l’une des difficultés majeures des patients atteints de troubles envahissants du développement (TED). Or, la perception des mouvements humains contribue à la mise en place des comportements sociaux et représenterait un « marqueur » du développement de la cognition sociale. Cette étude de suivi du regard et de pupillométrie visait à caractériser l’attention visuo-spatiale et la charge cognitive au cours de la perception de mouvements biologiques humains porteurs d'intention sociale (MHS) chez 139 participants typiques (PaTYP) et 62 patients atteints d’un TED (PaTED). Chez les PaTYP, l’exploration augmente pour les MHS. Chez les PaTED, un déficit d’exploration des MHS est corrélé à la sévérité de la symptomatologie autistique globale. Ces anomalies de l’attention visuo-spatiale des PaTED réduiraient leur accès à l’information sociale et pourraient participer au trouble de l’interaction sociale et de la communication. / Social interaction is one of the main difficulties for patients with pervasive developmental disorders (PDD). However, the perception of human movement contributes to the development of social behavior and represents a "marker" for the development of social cognition. This eye tracking and pupillometric study aims to characterize the visuospatial attention and cognitive load during perception of social human biological motion (SHM) in 139 typical participants (PaTYP) and 62 patients with ASD (PaTED). In PaTYP, exploration increases for SHM. In PaTED, deficit of the exploration of MHS is correlated with the severity of the global autistic symptomatology. These abnormalities of visuospatial attention in PaTED could reduce their access to social information and participate in social interaction and communication disorders.
9

Visual Analytics for Software Requirements Engineering

Reddivari, Sandeep Reddy 17 May 2014 (has links)
For many software projects, keeping requirements on track needs an effective and efficient path from data to decision. Visual analytics creates such a path that enables the human to extract insights by interacting with the relevant information. While various requirements visualization techniques exist, few have produced end-to-end values to practitioners. In this dissertation, we advance the literature on visual requirements analytics by characterizing its key components and relationships in a framework. We follow the goal-question-metric paradigm to define the framework by teasing out five conceptual goals (user, data, model, visualization, and knowledge), their specific operationalizations, and their interconnections. The framework allows us to not only assess existing approaches, but also create tool enhancements in a principled manner. We evaluate our enhanced tool supports both qualitatively and quantitatively. First, we evaluate our tool supports qualitatively through a case study where massive, heterogeneous, and dynamic requirements are processed, visualized, and analyzed. Working together with practitioners on a contemporary software project within its real-life context leads to the main ending that visual analytics can help tackle both open-ended visual exploration tasks and well-structured visual exploitation tasks in requirements engineering. In addition, the study helps the practitioners to reach actionable decisions in a wide range of areas relating to their project, ranging from theme and outlier identification, over requirements tracing, to risk assessment. Overall our work illuminates how the data-to-decision analytical capabilities could be improved by the increased interactivity of requirements visualization. Although many new visual analytics tools, techniques and methods are being developed, still there is a lack of understanding of how to evaluate the performance of such tools. We conducted an experiment to assess the performance (time and correctness) of our visual analytics tool support in solving requirements engineering tasks. Our study provides initial evidence and insights for visual analytics in requirements engineering and sheds light on many challenging open questions.
10

Explorative Visual Analysis of Rap Music

Meinecke, Christofer, Hakimi, Ahmad Dawar, Jänicke, Stefan 04 May 2023 (has links)
Detecting references and similarities in music lyrics can be a difficult task. Crowdsourced knowledge platforms such as Genius. can help in this process through user-annotated information about the artist and the song but fail to include visualizations to help users find similarities and structures on a higher and more abstract level. We propose a prototype to compute similarities between rap artists based on word embedding of their lyrics crawled from Genius. Furthermore, the artists and their lyrics can be analyzed using an explorative visualization system applying multiple visualization methods to support domain-specific tasks.

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