12 research outputs found

    Analysis domain model for shared virtual environments

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    The field of shared virtual environments, which also encompasses online games and social 3D environments, has a system landscape consisting of multiple solutions that share great functional overlap. However, there is little system interoperability between the different solutions. A shared virtual environment has an associated problem domain that is highly complex raising difficult challenges to the development process, starting with the architectural design of the underlying system. This paper has two main contributions. The first contribution is a broad domain analysis of shared virtual environments, which enables developers to have a better understanding of the whole rather than the part(s). The second contribution is a reference domain model for discussing and describing solutions - the Analysis Domain Model

    Data management in distributed shared virtual worlds

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    Research efforts in Virtual Worlds domain have been mainly devoted to user interfaces, communication supports and consistency issues. To the best of our knowledge, no works clearly focused on the global problem of managing virtual world’s data. The promise of future large persistent virtual worlds, evolving during a long period of time and with large number of participants makes the question of data management even more crucial. This paper introduces the global problem of managing data in virtual worlds and reports our research work in using data management services for virtual worlds platforms

    The Effect of Embodied Anthropomorphism of Personal Assistants on User Perceptions

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    gEYEded: Subtle and Challenging Gaze-Based Player Guidance in Exploration Games

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    This paper investigates the effects of gaze-based player guidance on the perceived game experience, performance, and challenge in a first-person exploration game. In contrast to existing research, the proposed approach takes the game context into account by providing players not only with guidance but also granting them an engaging game experience with a focus on exploration. This is achieved by incorporating gaze-sensitive areas that indicate the location of relevant game objects. A comparative study was carried out to validate our concept and to examine if a game supported with a gaze guidance feature triggers a more immersive game experience in comparison to a crosshair guidance version and a solution without any guidance support. In general, our study findings reveal a more positive impact of the gaze-based guidance approach on the experience and performance in comparison to the other two conditions. However, subjects had a similar impression concerning the game challenge in all conditions

    Resource optimization and dynamic state management in a collaborative virtual environment.

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    Yim-Pan Chui.Thesis (M.Phil.)--Chinese University of Hong Kong, 2001.Includes bibliographical references (leaves 126-132).Abstracts in English and Chinese.Abstract --- p.iiAcknowledgments --- p.vChapter 1 --- Introduction --- p.1Chapter 1.1 --- Introduction to Collaborative Virtual Environments --- p.1Chapter 1.2 --- Barriers to Resource Management and Optimization --- p.3Chapter 1.3 --- Thesis Contributions --- p.5Chapter 1.4 --- Application of this Research Work --- p.6Chapter 1.5 --- Thesis Organization --- p.6Chapter 2 --- Resource Optimization - Intelligent Server Partitioning --- p.9Chapter 2.1 --- Introduction --- p.9Chapter 2.2 --- Server Partitioning --- p.13Chapter 2.2.1 --- Related Works --- p.15Chapter 2.2.2 --- Global Optimization Approaches --- p.17Chapter 2.3 --- Hybrid Genetic Algorithm Paradigm --- p.17Chapter 2.3.1 --- Drawbacks of traditional GA --- p.18Chapter 2.3.2 --- Problem Modeling --- p.19Chapter 2.3.3 --- Discussion --- p.24Chapter 2.4 --- Results --- p.25Chapter 2.5 --- Concluding Remarks --- p.28Chapter 3 --- Dynamic State Management - Dead Reckoning of Attitude --- p.32Chapter 3.1 --- Introduction to Dynamic State Management --- p.32Chapter 3.2 --- The Dead Reckoning Approach --- p.35Chapter 3.3 --- Attitude Dead Reckoning by Quaternion --- p.37Chapter 3.3.1 --- Modeling of the Paradigm --- p.38Chapter 3.3.2 --- Prediction Step --- p.39Chapter 3.3.3 --- Convergence Step --- p.40Chapter 3.3.4 --- Overall Algorithm --- p.46Chapter 3.4 --- Results --- p.47Chapter 3.5 --- Conclusion --- p.51Chapter 4 --- Polynomial Attitude Extrapolation --- p.52Chapter 4.1 --- Introduction --- p.52Chapter 4.2 --- Related Works on Kalman Filtering --- p.53Chapter 4.3 --- Historical Propagation of Quaternion --- p.54Chapter 4.3.1 --- Cumulative Extrapolation --- p.54Chapter 4.3.2 --- Method I. Vandemonde Approach --- p.55Chapter 4.3.3 --- Method II. Lagrangian Approach --- p.58Chapter 4.4 --- History-Based Attitude Management --- p.60Chapter 4.4.1 --- Multi-order Prediction --- p.60Chapter 4.4.2 --- Adaptive Attitude Convergence --- p.63Chapter 4.4.3 --- Overall Algorithm --- p.67Chapter 4.5 --- Results --- p.69Chapter 4.6 --- Conclusion --- p.77Chapter 5 --- Forward Difference Approach on State Estimation --- p.78Chapter 5.1 --- Introduction --- p.78Chapter 5.2 --- Positional Forward Differencing --- p.79Chapter 5.3 --- Forward Difference on Quaternion Space --- p.80Chapter 5.3.1 --- Attitude Forward Differencing --- p.83Chapter 5.3.2 --- Trajectory Blending --- p.84Chapter 5.4 --- State Estimation --- p.86Chapter 5.5 --- Computational Efficiency --- p.87Chapter 5.6 --- Results --- p.88Chapter 5.7 --- Conclusion --- p.96Chapter 6 --- Predictive Multibody Kinematics --- p.98Chapter 6.1 --- Introduction --- p.98Chapter 6.2 --- Dynamic Management of Multibody System --- p.100Chapter 6.2.1 --- Multibody Representation --- p.100Chapter 6.2.2 --- Paradigm Overview --- p.101Chapter 6.3 --- Motion Estimation by Joint Extrapolation --- p.102Chapter 6.3.1 --- Individual Joint Extrapolation --- p.102Chapter 6.3.2 --- Forward Propagation of Joint State --- p.104Chapter 6.3.3 --- Pose Correction --- p.107Chapter 6.4 --- Limitations on Predictive Articulated State Management --- p.108Chapter 6.5 --- Implementation and Results --- p.109Chapter 6.6 --- Conclusion --- p.112Chapter 7 --- Complete System Architecture --- p.113Chapter 7.1 --- Server Cluster Model --- p.113Chapter 7.1.1 --- Peer-Server Systems --- p.114Chapter 7.1.2 --- Server Hierarchies --- p.114Chapter 7.2 --- Multi-Level Resource Management --- p.115Chapter 7.3 --- Aggregation of State Updates --- p.116Chapter 7.4 --- Implementation Issues --- p.117Chapter 7.4.1 --- Medical Visualization --- p.117Chapter 7.4.2 --- Virtual Walkthrough Application --- p.118Chapter 7.5 --- Conclusion --- p.119Chapter 8 --- Conclusions and Future directions --- p.121Chapter 8.1 --- Conclusion --- p.121Chapter 8.2 --- Future Research Directions --- p.122Chapter A --- Quaternion Basis --- p.124Chapter A.1 --- Basic Quaternion Mathematics --- p.124Chapter A.2 --- The Exponential and Logarithmic Maps --- p.125Bibliography --- p.12

    Investigation of an emotional virtual human modelling method

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    In order to simulate virtual humans more realistically and enable them life-like behaviours, several exploration research on emotion calculation, synthetic perception, and decision making process have been discussed. A series of sub-modules have been designed and simulation results have been presented with discussion. A visual based synthetic perception system has been proposed in this thesis, which allows virtual humans to detect the surrounding virtual environment through a collision-based synthetic vision system. It enables autonomous virtual humans to change their emotion states according to stimuli in real time. The synthetic perception system also allows virtual humans to remember limited information within their own First-in-first-out short-term virtual memory. The new emotion generation method includes a novel hierarchical emotion structure and a group of emotion calculation equations, which enables virtual humans to perform emotionally in real-time according to their internal and external factors. Emotion calculation equations used in this research were derived from psychologic emotion measurements. Virtual humans can utilise the information in virtual memory and emotion calculation equations to generate their own numerical emotion states within the hierarchical emotion structure. Those emotion states are important internal references for virtual humans to adopt appropriate behaviours and also key cues for their decision making. The work introduces a dynamic emotional motion database structure for virtual human modelling. When developing realistic virtual human behaviours, lots of subjects were motion-captured whilst performing emotional motions with or without intent. The captured motions were endowed to virtual characters and implemented in different virtual scenarios to help evoke and verify design ideas, possible consequences of simulation (such as fire evacuation). This work also introduced simple heuristics theory into decision making process in order to make the virtual human’s decision making more like real human. Emotion values are proposed as a group of the key cues for decision making under the simple heuristic structures. A data interface which connects the emotion calculation and the decision making structure together has also been designed for the simulation system.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    The Future of Coral Reefs

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    This volume contains a series of papers prepared for presentation at the 14th International Coral Reef Symposium, originally planned for July 2020 in Bremen, Germany, but postponed until 2021 (online) and 2022 (in person) because of the COVID-19 pandemic. It contains a series of papers illustrating the breadth of modern studies on coral reefs and the response of the reef science community to the threats that coral reefs now face, above all from climate change. The first group of papers focus on the biology of a selection of reef organisms, ranging from sea fans to coral dwelling crabs. The next group describe studies of coral communities and ecological interactions in regions as diverse as Florida, Kenya, Colombia, and Norway. Further papers describe investigations into the effects of global warming (in the Maldives and in Timor-Leste) and of other impacts (UV blockers, ocean acidification). The final two papers describe the latest applications of satellite and camera technology to the challenge of mapping and monitoring reefs

    Uma arquitectura de software dinùmica para a criação de ambientes de interacção social regulada na Web

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    Tese de Doutoramento em InformĂĄtica - Área de Especialização em Tecnologia da ProgramaçãoNas Ășltimas dĂ©cadas assistimos a uma mudança paradigmĂĄtica na utilização das tecnologias da informação e comunicação que potenciaram a criação de uma sociedade de informação e conhecimento, abrangendo e influenciando praticamente todos os domĂ­nios da sociedade. O tradicional uso das tecnologias de informação e comunicação no auxĂ­lio Ă  execução de actividades de Ăąmbito profissional, numa interacção restrita entre homem e mĂĄquina, deu lugar a ambientes virtuais de interacção social, onde pessoas interagem com pessoas, criando relaçÔes estreitas e realizando as mais diversas actividades. O crescimento da Internet e das tecnologias associadas fomentou o crescimento e difusĂŁo dos ambientes virtuais de interacção social, tornando-os acessĂ­veis `a grande maioria da população. Actualmente estes ambientes estĂŁo espalhados por toda a Internet e abrangem um vasto leque de ĂĄreas, da educação ao entretenimento. Contudo, a imaturidade associada ao rĂĄpido crescimento destes ambientes levou a que fossem descurados factores que actualmente condicionam a interacção social, nomeadamente ao nĂ­vel da sua coordenação e regulação. A regulação e coordenação da interacção social nos ambientes virtuais pode constituir uma solução possĂ­vel para organização da actual interacção “ad hoc”, que persiste nestes ambientes, contribuindo inerentemente para o aumento da sua credibilidade. Nesta tese Ă© proposto um modelo para a regulação da interacção social e controlo dos ambientes virtuais: o modelo dos Teatros Sociais. O conceito de Teatro Social resulta da aplicação da metĂĄfora teatral a ambientes virtuais de interacção social destinados a reproduzir virtualmente situaçÔes do quotidiano. Dentro destes ambientes os utilizadores tornam-se actores, desempenhando papĂ©is bem definidos, num cenĂĄrio virtual de interacção conhecido e, idealmente, estabelecido de forma comum. O modelo dos Teatros Sociais Ă© implementado por uma arquitectura de software dinĂąmica que permite a criação de ambientes de interacção regulados e assegura a adaptação dos conteĂșdos da interacção aos canais de comunicação dos utilizadores, embora condicionados pelas restriçÔes tecnolĂłgicas dos dispositivos usados na interacção. Para a validação do modelo e da arquitectura de suporte foram criados dois casos de estudo que suportaram um conjunto de experiĂȘncias realizadas com utilizadores reais.Throughout the last decades we have observed a paradigmatic change on the use of information and communication technologies, which have powered the creation of an information and knowledge society, covering and influencing almost every domain of society. The traditional usage of information and communication technologies as an aid to the execution of professional activities, in a restrictive man-machine interaction, has given way to social interaction virtual environments where people interact with each other, creating close relationships and doing the most different activities. The growth of the Internet and its associated technologies encouraged the expansion and diffusion of virtual environments where social interaction takes place, allowing easy access to the great majority of population. Nowadays these environments are spread all over the Internet and cover a vast rage of areas, from education to entertainment. However, immaturity together with the fast growth of these environments led to the disregard of factors, which condition interaction today, namely the coordination and regulation of interaction activities. The regulation and coordination of interaction in social, virtual interaction environments may be a possible solution to the organisation of today’s “ad hoc” interaction, which persists in these environments, inherently contributing to the increase of its credibility. In this Thesis a model to regulate social interaction and control virtual environments is proposed: the Social Theatres model. Social Theatres stand for the application of the theatrical metaphor to social virtual environments, intended to virtually reproduce some of the common and useful people’s interaction contexts. Inside these environments, users become actors, playing previously well defined roles within a well known, commonly established virtual interaction scenario. The Social Theatres model is implemented by a dynamic software architecture that allows the creation of regulated interaction environments and guarantees adaptation to users’ devices and input channels. In order to validate the model and the supporting architecture two case studies were created, which supported a group of experiments carried out with real users.Fundação para a CiĂȘncia e Tecnologia (FCT) - no Ăąmbito do III Quadro ComunitĂĄrio de Apoio, comparticipado pelo Fundo Social EuropeuMinistĂ©rio da CiĂȘncia e do Ensino Superior (MCES) - Bolsa de Doutoramento com a referĂȘncia SFRH/BD/10304/200
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