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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.
261

Environnement virtuel générateur d’émotions

Brosseau, Pierre-Olivier 08 1900 (has links)
Les émotions jouent un rôle important dans la prise de décision quotidienne. En effet, elles influencent grandement la manière dont les individus interagissent avec leur environnement. Dans cette étude nous avons premièrement conçu un environnement virtuel de conduite automobile, puis créé des scénarios générateurs d’émotions à l’aide de la méthode Belief-Desire-Intention. Nous avons évalué l’efficacité de ces scénarios à l’aide d’un groupe de 30 personnes et d’un casque électroencéphalogramme pour mesurer leurs émotions. On observe que plus de 70% des scénarios conçus avec cette méthode ont généré l’émotion que l’on avait anticipée chez 52% à 76% des participants. La deuxième phase de cette expérience porte sur la réduction d’émotions avec un agent correcteur. Nous avons noté une efficacité de la réduction des émotions allant de 36.4% jusqu’à 70.0% des participants à travers les différents scénarios. / Emotions play an important role in daily decision-making. Indeed, they greatly influence how individuals interact with their environment. In this study, we first designed a virtual driving environment and various emotion-inducing scenarios using the Belief-Desire-Intention method. We evaluated the effectiveness of these scenarios with a group of 30 people and an EEG headset to measure the emotions. Over 70% of scenarios designed with this method induced the emotion that had been anticipated in 52% to 76% of the participants. The second phase of this experiment is the reduction of emotions with a corrective agent. We noted an efficiency in reducing emotions ranging from 36.4% to 70.0% of the participants through the different scenarios.
262

Wireless communications infrastructure for collaboration in common space

Metingu, Kivanc 03 1900 (has links)
Approved for public release, distribution is unlimited / Modern technology is making virtual environments a part of daily life. However, some constraints about the usage of virtual environments, such as the need for high performance and well-configured computers, prevent users from accessing virtual environments in some places other than special computer rooms. Mobile devices may be used to solve this limitation in a virtual environment. The remote-control approach to access virtual worlds on the Internet or on a corporate network is a new concept that opens new doors to users. First step of this approach is already in use, such as games implemented for mobile devices using the screen of a mobile device as display, and has given satisfying results for some users. This research will take the user, who not only wants to be mobile but also does not want to sacrifice high resolution textures and complex models, closer to his/her goal. Mobile devices provide mobility to the user, but sacrifice not only the reality of the virtual environments but also screen size, which is very important for visibility of complex virtual environments. The hybrid approach with wireless internet connection by using mobile devices as remote control gives the user the advantages of mobility over desktop PCs. On the other hand, the realism provided by high-quality PCs on the server side exceeds the capabilities of mobile devices. / Lieutenant Junior Grade, Turkish Navy
263

Design and implementation of a DSP-based control interface unit (CIU)

Kavousanos-Kavousanakis, Andreas 03 1900 (has links)
Approved for public release, distribution is unlimited / This research involves the development of a human-body motion tracking system constructed with the use of commercial off-the-shelf (COTS) components. The main component of the system investigated in this thesis is the Control Interface Unit (CIU). The CIU is a component designed to receive data from the magnetic, angular rate, and gravity (MARG) sensors and prepare them to be transmitted through a wireless configuration. A simple and effective algorithm is used to filter the sensor data without singularities, providing the measured attitude in the quaternion form for each human limb. Initial calibration of the MARG sensors is also performed with the use of linear calibrating algorithms. The testing and evaluation of the whole system is performed by MATLABʼ and SIMULINKʼ simulations, and by the realtime visualization using a human avatar designed with the X3D graphics specifications. Through this research, it is discovered that the MARG sensors had to be redesigned to overcome an erratum on the Honeywell magnetometer HMC1051Z data sheet. With the redesigned MARG sensors, the testing results showed that the CIU was performing extremely well. The overall motion tracking system is capable of tracking human body limb motions in real time. / Lieutenant Junior Grade, Hellenic Navy
264

Learning English in a Multi-User Virtual Environment : Exploring Factors Affecting Participation

Wang, Airong January 2017 (has links)
Online language learning and teaching is a field that has received a significant amount of research attention. What factors could affect student participation in simpler online learning environments has been investigated by researchers, but there has been limited study of factors affecting participation in complex Multi-User Virtual Environments. By using the typical Multi-User Virtual Environment Second Life, three English courses offered by Swedish universities were examined in this thesis. The courses were video-recorded, and selected parts of the recordings were transcribed. The transcribed recordings were complemented by author(s)’ observation, participants’ reflection, an online questionnaire and an online interview. Participation from the courses was measured both quantitatively and qualitatively. Quantitative methods were used to measure, for example, floor space, number of utterances, turn length, number of turns; the qualitative analysis centered on, for instance, utterance functions, discourse analysis, and Conversational Analysis. The results were published in five papers that focused on different central factors affecting participation in Second Life. In this thesis, the findings from those articles are synthesized. Furthermore, on the basis of the findings, a general model of factors affecting participation is presented and discussed to highlight that different factors interrelate and that some factors are particularly important in terms of affecting participation in Multi-User Virtual Environments. These are students’ technical skills, task design, course design, technical support, and Second Life technology. The complex technology also places critical demands on teachers’ technical skills, teaching strategies, and roles that teachers should play. Finally, this thesis argues that it is important to choose a suitable technology for an English course.
265

Un oeil sur la langue : aspects neuro-cognitifs du processus de la navigation chez l'aveugle-né

Chebat, Daniel-Robert 03 1900 (has links)
La vision est un élément très important pour la navigation en général. Grâce à des mécanismes compensatoires les aveugles de naissance ne sont pas handicapés dans leurs compétences spatio-cognitives, ni dans la formation de nouvelles cartes spatiales. Malgré l’essor des études sur la plasticité du cerveau et la navigation chez les aveugles, les substrats neuronaux compensatoires pour la préservation de cette fonction demeurent incompris. Nous avons démontré récemment (article 1) en utilisant une technique d’analyse volumétrique (Voxel-Based Morphometry) que les aveugles de naissance (AN) montrent une diminution de la partie postérieure de l’hippocampe droit, structure cérébrale importante dans la formation de cartes spatiales. Comment les AN forment-ils des cartes cognitives de leur environnement avec un hippocampe postérieur droit qui est significativement réduit ? Pour répondre à cette question nous avons choisi d’exploiter un appareil de substitution sensorielle qui pourrait potentiellement servir à la navigation chez les AN. Cet appareil d’affichage lingual (Tongue display unit -TDU-) retransmet l’information graphique issue d’une caméra sur la langue. Avant de demander à nos sujets de naviguer à l’aide du TDU, il était nécessaire de nous assurer qu’ils pouvaient « voir » des objets dans l’environnement grâce au TDU. Nous avons donc tout d’abord évalué l’acuité « visuo »-tactile (article 2) des sujets AN pour les comparer aux performances des voyants ayant les yeux bandées et munis du TDU. Ensuite les sujets ont appris à négocier un chemin à travers un parcours parsemé d’obstacles i (article 3). Leur tâche consistait à pointer vers (détection), et contourner (négociation) un passage autour des obstacles. Nous avons démontré que les sujets aveugles de naissance non seulement arrivaient à accomplir cette tâche, mais encore avaient une performance meilleure que celle des voyants aux yeux bandés, et ce, malgré l’atrophie structurelle de l’hippocampe postérieur droit, et un système visuel atrophié (Ptito et al., 2008). Pour déterminer quels sont les corrélats neuronaux de la navigation, nous avons créé des routes virtuelles envoyées sur la langue par le biais du TDU que les sujets devaient reconnaitre alors qu’ils étaient dans un scanneur IRMf (article 4). Nous démontrons grâce à ces techniques que les aveugles utilisent un autre réseau cortical impliqué dans la mémoire topographique que les voyants quand ils suivent des routes virtuelles sur la langue. Nous avons mis l’emphase sur des réseaux neuronaux connectant les cortex pariétaux et frontaux au lobe occipital puisque ces réseaux sont renforcés chez les aveugles de naissance. Ces résultats démontrent aussi que la langue peut être utilisée comme une porte d’entrée vers le cerveau en y acheminant des informations sur l’environnement visuel du sujet, lui permettant ainsi d’élaborer des stratégies d’évitement d’obstacles et de se mouvoir adéquatement. / Vision is a very important tool for navigation in general. Due to compensatory mechanisms people who are blind from birth are not handicapped in spatio-cognitive abilities, nor in the formation of novel spatial maps. Despite the growing volume of studies on brain plasticity and navigation in the blind, the compensatory neural substrates or the preservation of this function remain unclear. We have recently demonstrated (article 1) by using volumetric analysis techniques (Voxel-Based Morphometry) that early blind individuals (EB) show a reduction of the posterior end of the hippocampus on the right side. This cerebral structure is important for the formation of cognitive maps. How do EB form maps of their environment with a significantly reduced posterior right hippocampus? To answer this question we chose to exploit a sensory substitution device that could potentially serve navigation in EB. This tongue display unit (TDU) is capable of transmitting pictorial imagery in the form of electricity on the tongue. Before asking our participants to navigate using the TDU, it was necessary to ascertain that they could really « see » objects in the environment using the TDU. We thus evaluated the « visuo »-tactile acuity (article 2) of EB compared to sighted blindfolded participants using the TDU. Participants later learned to negotiate a path through an obstacle course (article 3). Their task consisted of pointing to (detection), and avoiding (negotiation) obstacles while advancing through the hallway. We demonstrated that despite a reduced right posterior hippocampus, and an iii atrophied visual system (Ptito et al., 2008) EB not only were able to accomplish this task, but had a better performance than the blindfolded sighted controls. To determine what the neural correlates of navigation in EB are, we devised an fMRI compatible virtual route task conveyed through the tongue (article 4). Participants had to learn to navigate the routes and recognize them. We showed that EB use another cortical network involved in cognitive mapping than the sighted when recognizing routes on the tongue. We have emphasized neural networks connecting parietal and frontal cortices since they are re-enforced in EB. These results show that the tongue can be used as a portal to the brain by transferring pictorial information from the visual environment of participants, allowing the elaboration of strategies to avoid obstacles and move around in their environment.
266

Reconnaissance émotionnelle faciale et psychopathie : un protocole exploratoire à l’aide de personnages virtuels animés

Cigna, Marie-Hélène 12 1900 (has links)
La présente recherche est constituée de deux études. Dans l’étude 1, il s’agit d’améliorer la validité écologique des travaux sur la reconnaissance émotionnelle faciale (REF) en procédant à la validation de stimuli qui permettront d’étudier cette question en réalité virtuelle. L’étude 2 vise à documenter la relation entre le niveau de psychopathie et la performance à une tâche de REF au sein d’un échantillon de la population générale. Pour ce faire, nous avons créé des personnages virtuels animés de différentes origines ethniques exprimant les six émotions fondamentales à différents niveaux d’intensité. Les stimuli, sous forme statique et dynamique, ont été évalués par des étudiants universitaires. Les résultats de l’étude 1 indiquent que les stimuli virtuels, en plus de comporter plusieurs traits distinctifs, constituent un ensemble valide pour étudier la REF. L’étude 2 a permis de constater qu’un score plus élevé à l’échelle de psychopathie, spécifiquement à la facette de l’affect plat, est associé à une plus grande sensibilité aux expressions émotionnelles, particulièrement pour la tristesse. Inversement, un niveau élevé de tendances criminelles est, pour sa part, associé à une certaine insensibilité générale et à un déficit spécifique pour le dégoût. Ces résultats sont spécifiques aux participants masculins. Les données s’inscrivent dans une perspective évolutive de la psychopathie. L’étude met en évidence l’importance d’étudier l’influence respective des facettes de la personnalité psychopathique, ce même dans des populations non-cliniques. De plus, elle souligne la manifestation différentielle des tendances psychopathiques chez les hommes et chez les femmes. / The current research consists of two studies. In study 1, the goal is to increase ecological validity of studies on facial recognition, by validating and comparing a set of synthetic characters we created with the empirically validated Pictures of Facial Affect. Further, these stimuli would provide a method to assess facial expression recognition in immersive virtual environments. Study 2 aims to further understand the relationship between psychopathy and emotional information processing using dynamic emotions in a community sample. To accomplish this, we created dynamic characters displaying the six basic emotions at different intensity levels. The stimuli were evaluated by undergraduate students. Findings provide empirical support for the validity of the facial expressions we created, which possess distinguishing attributes and are of particular utility in regard to emotion research. In study 2, results suggest that a higher score on Factor 1, specifically the callous affect subscale, is associated with a greater sensitivity to emotional expressions, in particular sadness expressions. In addition, high levels of criminal tendencies are associated with poorer performance on the task and a specific impairment in the recognition of disgust. These results are specific to male participants. Data supports the conceptualisation of psychopathy as a life-history strategy. The study also highlights the influence of the distinct facets of psychopathy in facial affect recognition and the differential manifestation of psychopathic personality between men and women.
267

MusE-XR: musical experiences in extended reality to enhance learning and performance

Johnson, David 23 July 2019 (has links)
Integrating state-of-the-art sensory and display technologies with 3D computer graphics, extended reality (XR) affords capabilities to create enhanced human experiences by merging virtual elements with the real world. To better understand how Sound and Music Computing (SMC) can benefit from the capabilities of XR, this thesis presents novel research on the de- sign of musical experiences in extended reality (MusE-XR). Integrating XR with research on computer assisted musical instrument tutoring (CAMIT) as well as New Interfaces for Musical Expression (NIME), I explore the MusE-XR design space to contribute to a better understanding of the capabilities of XR for SMC. The first area of focus in this thesis is the application of XR technologies to CAMIT enabling extended reality enhanced musical instrument learning (XREMIL). A common approach in CAMIT is the automatic assessment of musical performance. Generally, these systems focus on the aural quality of the performance, but emerging XR related sensory technologies afford the development of systems to assess playing technique. Employing these technologies, the first contribution in this thesis is a CAMIT system for the automatic assessment of pianist hand posture using depth data. Hand posture assessment is performed through an applied computer vision (CV) and machine learning (ML) pipeline to classify a pianist’s hands captured by a depth camera into one of three posture classes. Assessment results from the system are intended to be integrated into a CAMIT interface to deliver feedback to students regarding their hand posture. One method to present the feedback is through real-time visual feedback (RTVF) displayed on a standard 2D computer display, but this method is limited by a need for the student to constantly shift focus between the instrument and the display. XR affords new methods to potentially address this limitation through capabilities to directly augment a musical instrument with RTVF by overlaying 3D virtual objects on the instrument. Due to limited research evaluating effectiveness of this approach, it is unclear how the added cognitive demands of RTVF in virtual environments (VEs) affect the learning process. To fill this gap, the second major contribution of this thesis is the first known user study evaluating the effectiveness of XREMIL. Results of the study show that an XR environment with RTVF improves participant performance during training, but may lead to decreased improvement after the training. On the other hand,interviews with participants indicate that the XR environment increased their confidence leading them to feel more engaged during training. In addition to enhancing CAMIT, the second area of focus in this thesis is the application of XR to NIME enabling virtual environments for musical expression (VEME). Development of VEME requires a workflow that integrates XR development tools with existing sound design tools. This presents numerous technical challenges, especially to novice XR developers. To simplify this process and facilitate VEME development, the third major contribution of this thesis is an open source toolkit, called OSC-XR. OSC-XR makes VEME development more accessible by providing developers with readily available Open Sound Control (OSC) virtual controllers. I present three new VEMEs, developed with OSC-XR, to identify affordances and guidelines for VEME design. The insights gained through these studies exploring the application of XR to musical learning and performance, lead to new affordances and guidelines for the design of effective and engaging MusE-XR. / Graduate
268

Architecture événementielle pour les environnements virtuels collaboratifs sur le web : application à la manipulation et à la visualisation d'objets en 3D / Event-based architecture for web-based virtual collaborative environments : application to manipulation and visualisation of 3D objects

Desprat, Caroline 01 December 2017 (has links)
L’évolution technologique du web durant ces dernières années a favorisé l’arrivée d’environnements virtuels collaboratifs pour la modélisation 3D à grande échelle. Alors que la collaboration réunit dans un même espace partagé des utilisateurs distants géographiquement pour un objectif de collaboration commun, les ressources matérielles qu'ils apportent (calcul, stockage, 3D ...) avec leurs connaissances sont encore trop rarement utilisées et cela constitue un défi. Il s'agit en effet de proposer un système simple, performant et transparent pour les utilisateurs afin de permettre une collaboration efficace à la fois sur le volet computationnel mais aussi, bien entendu, sur l'aspect métier lié à la modélisation 3D sur le web. Pour rendre efficace le passage à l’échelle, de nombreux systèmes utilisent une architecture réseau dite "hybride", combinant client serveur et pair-à-pair. La réplication optimiste s'adapte bien aux propriétés de ces environnements répartis : la dynamicité des utilisateurs et leur nombre, le type de donnée traitées (3D) et leur taille. Cette thèse présente un modèle pour les systèmes d’édition collaborative en 3D sur le web. L'architecture cliente (3DEvent) permet de déporter les aspects métiers de la 3D au plus près de l’utilisateur sous la forme d’évènements. Cette architecture orientée événements repose sur le constat d’un fort besoin de traçabilité et d’historique sur les données 3D lors de l’assemblage d’un modèle. Cet aspect est porté intrinsèquement par le patron de conception event-sourcing. Ce modèle est complété par la définition d’un intergiciel en pair-à-pair. Sur ce dernier point, nous proposons d'utiliser la technologie WebRTC qui présente une API familière aux développeurs de services en infonuagique. Une évaluation portant sur deux études utilisateur concernant l’acceptance du modèle proposé a été menée dans le cadre de tâches d’assemblage de modèles 3D sur plusieurs groupes d’utilisateurs. / Web technologies evolutions during last decades fostered the development of collaborative virtual environments for 3D design at large scale. Despite the fact that collaborative environments gather in a same shared space geographically distant users in a common objective, the hardware ressources of their clients (calcul, storage, graphics ...) are often underused because of the challenge it represents. It is indeed a matter of offering an easy-to-use, efficient and transparent collaborative system to the user supporting both computationnal and 3D design visualisation and business logic needs in heterogeneous web environments. To scale well, numerous systems use a network architecture called "hybrid", combining both client-server and peer-to-peer. Optimistic replication is well adapted to distributed application such as 3D collaborative envionments : the dynamicity of users and their numbers, the 3D data type used and the large amount and size of it.This document presents a model for 3D web-based collaborative editing systems. This model integrates 3DEvent, an client-based architecture allowing us to bring 3D business logic closer to the user using events. Indeed, the need of traceability and history awareness is required during 3D design especially when several experts are involved during the process. This aspect is intrinsec to event-sourcing design pattern. This architecture is completed by a peer-to-peer middleware responsible for the synchronisation and the consistency of the system. To implement it, we propose to use the recent web standard API called WebRTC, close to cloud development services know by developers. To evaluate the model, two user studies were conducted on several group of users concerning its responsiveness and the acceptance by users in the frame of cooperative assembly tasks of 3D models.
269

Como atingir a interação, visando à construção do conhecimento e à aprendizagem de língua portuguesa, em ambientes virtuais

Reis, Renata Cristina dos 20 May 2009 (has links)
Made available in DSpace on 2016-04-28T19:34:37Z (GMT). No. of bitstreams: 1 Renata Cristina dos Reis.pdf: 614525 bytes, checksum: 4e018f4079f3bc5a2cd6a225a61a3346 (MD5) Previous issue date: 2009-05-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Study on interaction, in distance education of Portuguese Language, carried out in a semi-presence university course. The inquiry started from the following question: How to reach the interaction, aiming at the construction of knowledge and the learning of Portuguese, in virtual environments? In the search for the answer, the objective was to analyze the development of the possible strategies of interaction in the virtual environment of education and learning of Portuguese, in a collective perspective, using the subject "Comunicação e Expressão" to verify the interaction between the participants and the role of the teacher as the mediator of this process. The course was hosted in Moodle Platform, and the research was based on the relations between interaction, mediation and collaborative work, agreeing with Masetto's proposal for the use of specific pedagogical mediation strategies (2003) and (1999), as well as the possibilities of mediation proposed by Belloni (2006) and also Valente's view of virtual environments in a "virtual togetherness" perspective (2004). In a qualitative basis, the analyses were carried out based on textual dialogues that happened with the use of the following tools: E-mail, Discussion and Activities Forum and Chats. The conclusion was that the interventions of the tutor made the course become dynamic, with gradual evolution in collaborative work. The analyses showed that this dynamism enabled the re (elaboration) of concepts from the linking of individual solutions (self-learning) with group discussion (inter-learning) / Estudo sobre interação, em ensino de Língua Portuguesa a distância, realizado em curso semipresencial no ensino superior. A investigação partiu do seguinte questionamento: Como atingir a interação, visando à construção do conhecimento e à aprendizagem de LPO, em ambientes Virtuais? Na busca da resposta assumiu como objetivo analisar o desenvolvimento das possíveis estratégias de interação no ambiente virtual de ensino e aprendizagem em Língua Portuguesa, numa perspectiva coletiva, utilizando a disciplina Comunicação e Expressão para verificar a interação entre os participantes e o papel do professor como mediador pedagógico desse processo. O curso foi hospedado na plataforma Modlle e a pesquisa fundamentada nas relações existentes entre interação, mediação e trabalho colaborativo, compreendendo a utilização de estratégias específicas de mediação pedagógica segundo as idéias de Masetto (2003) e (1999), bem como as possibilidades de mediação conforme Belloni (2006) e de ambientes virtuais numa perspectiva do estar junto virtual de Valente (2004). De base qualitativa, as análises realizaram-se a partir de diálogos textuais selecionados na documentação relativa às interações ocorridas no ambiente virtual por meio das ferramentas Correio Eletrônico, Fórum de Discussão e Atividades e Bate-Papo. Concluiu-se que as intervenções do professor-tutor imprimiram uma dinâmica no curso, com evolução gradativa na perspectiva do trabalho colaborativo. As analises mostraram que tal dinâmica possibilitou a reflexão dos conceitos a partir da articulação das soluções individuais (auto-aprendizagem) com a discussão em grupo (interaprendizagem)
270

Evolução de estratégias e controle inteligente em sistemas multi-robóticos robustos

Pessin, Gustavo 22 February 2008 (has links)
Made available in DSpace on 2015-03-05T13:59:42Z (GMT). No. of bitstreams: 0 Previous issue date: 22 / Nenhuma / Este trabalho está relacionado com a aplicação de técnicas de Inteligência Artificial no desenvolvimento de um Sistema Multi-Agente robótico aplicado ao problema da monitoração e combate a incêndios em áreas florestais. O objetivo macro é evoluir estratrégias de formação de equipes de combate a incêndio (unidade de controle) e criar métodos robustos de navegação em agentes robóticos (unidades de combate), considerando um ambiente virtual de simulação realística.No sistema proposto, uma equipe de agentes autônomos trabalha cooperativamente a fim de realizar com sucesso a identificação e o combate a incêndios em áreas florestais, sem intervenção humana. O ambiente virtual 3D suporta uma série de características fundamentais para a simulação realística da operação, como terrenos irregulares, processos naturais e restrições físicas na criação e uso de robôs móveis. Este ambiente foi implementado através do uso das bibliotecas OSG, ODE e Demeter. A operacão multi-agente depende essencialmente de duas etapas: p / This work is related to the application of Artificial Intelligence techniques to develop a Multi-Agent Robotic System applied to the problem of monitoring wild forest fires and to the execution of fire fighting actions. Our main goal was to evolve strategies (control unit) in order to define the positioning of the fire-fighting autonomous robotic team and to create robust navigation methods used to control robotic agents (combat units). This work was developed based on simulations accomplished using a realistic 3D virtual environment, specially implemented for this purpose, using the software libraries OSG, Demeter and ODE. In the proposed system, a team of autonomous agents work cooperatively in order to successfully perform the identification and fighting of forest fires, without any human intervention. The 3D virtual environment includes several features for realistic simulation of this task, as for example, adoption of irregular terrains, natural processes simulation (e.g. fire propagation), and simulati

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