Continuous prewarping of time for multiuser interactive virtual environments

Dynamic multi-user interactions in a single networked virtual environment suffer from abrupt state transition problems due to communication delays arising from network latency--an action by one user only becoming apparent to another user after the communication delay. This results in a temporal suspension of the environment for the duration of the delay--the virtual world `hangs'--followed by an abrupt jump to make up for the time lost due to the delay so that the current state of the virtual world is displayed. These discontinuities appear unnatural and disconcerting to the users. This paper proposes a novel method of warping times associated with users to ensure that each user views a continuous version of the virtual world, such that no hangs or jumps occur despite other user interactions. Objects passed between users within the environment are parameterized, not by real time, but by a virtual local time, generated by continuously warping real time. This virtual time periodically realigns itself with real time as the virtual environment evolves. The concept of a local user dynamically warping the local time is also introduced. As a result, the users are shielded from viewing discontinuities within their virtual worlds, consequently enhancing the realism of the virtual environment.

Automatic camera control in virtual environments augmented using multiple sparse videos

Automated virtual camera control has been widely used in animation and interactive virtual environments. We have developed a multiple sparse camera based free view video system prototype that allows users to control the position and orientation of a virtual camera, enabling the observation of a real scene in three dimensions (3D) from any desired viewpoint. Automatic camera control can be activated to follow selected objects by the user. Our method combines a simple geometric model of the scene composed of planes (virtual environment), augmented with visual information from the cameras and pre-computed tracking information of moving targets to generate novel perspective corrected 3D views of the virtual camera and moving objects. To achieve real-time rendering performance, view-dependent textured mapped billboards are used to render the moving objects at their correct locations and foreground masks are used to remove the moving objects from the projected video streams. The current prototype runs on a PC with a common graphics card and can generate virtual 2D views from three cameras of resolution 768 x 576 with several moving objects at about 11 fps. (C)2011 Elsevier Ltd. All rights reserved.

A prestação de serviços nos ambientes físico e virtual: um estudo comparativo entre estratégias, estruturas e dimensões

A maioria dos analistas de negócios afirma que todas as empresas competirão no ambiente virtual até o final deste século. O desafio atual para as empresas que operam no ambiente físico é o de transferirem suas competências para o novo ambiente, que por sua vez cria novas e não antecipadas oportunidades. Este trabalho visa apresentar as ... dimensões e estruturas de cada ambiente, fornecendo aos administradores subsídios para a implementação de estratégias que permitam a transferência de competências entre os ambientes de forma adequada e eficaz. Para tanto foi realizada uma pesquisa exploratória sobre a estratégia competitiva de empresas norte-americanas do setor de serviços, tanto para caracterizar suas estratégias de atuação em ambos ambientes, como para analisar a forma que a transição do ambiente físico para o virtual foi realizada. Esta pesquisa contribuiu ainda para a formulação de um conjunto de estratégias comuns adotadas pelas empresas estudadas, o que em última análise pode ser caracterizado como "boas práticas" para a gestão da transição.

S-Educ: Um Simulador de Ambiente de Robótica Educacional em Plataforma Virtual

We propose a robotics simulation platform, named S-Educ, developed specifically for application in educational robotics, which can be used as an alternative or in association with robotics kits in classes involving the use of robotics. In the usually known approach, educational robotics uses robotics kits for classes which generally include interdisciplinary themes. The idea of this work is not to replace these kits, but to use the developed simulator as an alternative, where, for some reason, the traditional kits cannot be used, or even to use the platform in association with these kits. To develop the simulator, initially, we conducted research in the literature on the use of robotic simulators and robotic kits, facing the education sector, from which it was possible to define a set of features considered important for creating such a tool. Then, on the software development phase, the simulator S-Educ was implemented, taking into account the requirements and features defined in the design phase. Finally, to validate the platform, several tests were conducted with teachers, students and lay adults, in which it was used the simulator S-Educ, to evaluate its use in educational robotics classes. The results show that robotic simulator allows a reduction of financial costs, facilitate testing and reduce robot damage inherent to its use, in addition to other advantages. Furthermore, as a contribution to the community, the proposed tool can be used to increase adhesion of Brazilian schools to the methodologies of educational robotics or to robotics competitions

Managing large scale virtual environments using portals

This article describes a technique for Large Scale Virtual Environments (LSVEs) partitioning in hexagon cells and using portal in the cell interfaces to reduce the number of messages on the network and the complexity of the virtual world. These environments usually demand a high volume of data that must be sent only to those users who needs the information [Greenhalgh, Benford 1997].

Scalable distributed virtual environments using multicast application level

Most of architectures proposed for developing Distributed Virtual Environment (DVE) allow limited number of users. To support the development of applications using the internet infrastructure, with hundred or, perhaps, thousands users logged simultaneously on DVE, several techniques for managing resources, such as bandwidth and capability of processing, must be implemented. The strategy presented in this paper combines methods to attain the scalability required, In special the multicast protocol at application level.

Library in virtual reality: An innovative way for accessing, disseminating, and sharing information

This paper focuses on Virtual Reality (VR) as a very powerful technology that can be applied to the libraries, aiming at contributing to the activities of accessing, disseminating, and sharing information. The paper presents the VR concept and describes some libraries in virtual reality under utilization in different countries. In the final considerations, it is pointed out the use of virtual reality to develop libraries as collaborative virtual environments.

Virtual simulator for mobile robots navigation systems

This paper presents the virtual environment implementation for project simulation and conception of supervision and control systems for mobile robots, that are capable to operate and adapting in different environments and conditions. This virtual system has as purpose to facilitate the development of embedded architecture systems, emphasizing the implementation of tools that allow the simulation of the kinematic conditions, dynamic and control, with real time monitoring of all important system points. For this, an open control architecture is proposal, integrating the two main techniques of robotic control implementation in the hardware level: systems microprocessors and reconfigurable hardware devices. The implemented simulator system is composed of a trajectory generating module, a kinematic and dynamic simulator module and of a analysis module of results and errors. All the kinematic and dynamic results shown during the simulation can be evaluated and visualized in graphs and tables formats, in the results analysis module, allowing an improvement in the system, minimizing the errors with the necessary adjustments optimization. For controller implementation in the embedded system, it uses the rapid prototyping, that is the technology that allows, in set with the virtual simulation environment, the development of a controller project for mobile robots. The validation and tests had been accomplish with nonholonomics mobile robots models with diferencial transmission. © 2008 IEEE.

Sistema gerador de apoio a um dicionário temático visual-gestual baseado em realidade virtual

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Elaboração e avaliação de um ambiente virtual para o ensino/aprendizagem de embriologia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

SIMPLARCOM: simulador para planejamento de redes de comunicação sem fio utilizando realidade virtual e modelos de propagação

Este simulador é formado pela junção de técnicas de Realidade Virtual com modelos de propagação, desenvolvidos através dos estudos de rádio enlace, que descrevem a perda que o sinal transmitido sofre ao longo do percurso no ambiente. O simulador possui dois módulos. O primeiro permite a criação do ambiente virtual com o posicionamento, sobre um terreno, de prédios, árvores, carros, antenas e outras primitivas que permitem a construção de um ambiente tridimensional customizável. O segundo módulo permite a configuração dos parâmetros relacionados a propagação de sinal de antenas como a potência, a frequência, o ganho, etc., e também selecionar o modelo de propagação para a execução da simulação. Dentro deste segundo módulo, existe um submódulo responsável pelo estudo do planejamento da área de cobertura composta pelas antenas, em outras palavras, este submódulo simula a distância que cada antena no cenário consegue atingir e gera a respectiva área de cobertura. Para demonstrar a eficiência do simulador foram criados dois ambientes virtuais para testes. Um cenário representando um ambiente urbano onde empregou-se um modelo de propagação clássico, Okumura-Hata para cidades pequenas e médias, e um ambiente tridimensional arborizado utilizando um modelo especifico para simulação de propagação para regiões densamente arborizadas, desenvolvido na Universidade Federal do Pará chamado de Lyra-Castro-UFPA.

O processo de formação permanente em serviço e em exercício de formadores para a docência virtual

Pós-graduação em Educação - FCT

Procedimentos de jogadores no jogo virtual Colheita Feliz: a virtude e a regra

This study based on moral culture research and the theoretical Piagetian perspective aims to investigate the relation between virtue and rules in the procedures of participants in the Internet game Colheita Feliz (Happy Harvest) – an Orkut application. By means of descriptive qualitative analysis, the behavior of 60 participants in the game was observed during two months. The participants’ performance ranking was analyzed according to the procedures they used. The results showed predominance of the crop stealing procedure in comparison with the crop cultivation procedure and allowed to consider that the action of stealing of the participants was not guided by the universal principles of virtue, honesty or lack of it (moral domain) but by the playing convention for the game (social domain) favoring the stealing procedure, and also by personal domain (choices) and mutual agreement among the subjects participating in the game. The data did not indicate connections between the participants’ actions inside and outside virtual and real fields with regard to stealing, and reinforced the idea that rules are conventionalized in the domain of a group and depend on social interactions by which mutual respect among peers must prevail. The data also shows that morality is not the regulatory actions in the game. The results also showed the importance of carrying out research on procedures used by computer game players since such procedures can demonstrate cognitive, moral, affective and social aspects perceived during playful interaction situations.

Espaço virtual de um grupo de pesquisa: o olhar dos tutores

O Grupo de Estudos e Pesquisas de Tecnologia da Informação nos Processos de Trabalho em Enfermagem (GEPETE) visa produzir e socializar o conhecimento na área de tecnologia da informação e comunicação na saúde e enfermagem, articular a integração com grupos de pesquisas desta área e propiciar a participação de alunos. O estudo realizado pelos tutores teve como objetivo relatar a construção do ambiente virtual de aprendizagem (AVA) e a experiência dos tutores como mediadores de um grupo de pesquisa na plataforma Moodle. Para tanto, foi construído um AVA, realizada a mediação pedagógica sob a temática tutoria e o diagnóstico inicial em relação às dificuldades na utilização da tecnologia na interatividade e na comunicação, o que permitiu a proposição da continuidade da utilização da plataforma como um recurso para apoiar as atividades de pesquisa, oferecer aos líderes pesquisadores mecanismos para socialização dos projetos e possibilidades de orientação à distância.

Virtual sensing technology applied to a swarm of autonomous robots.

This thesis proposes a novel technology in the field of swarm robotics that allows a swarm of robots to sense a virtual environment through virtual sensors. Virtual sensing is a desirable and helpful technology in swarm robotics research activity, because it allows the researchers to efficiently and quickly perform experiments otherwise more expensive and time consuming, or even impossible. In particular, we envision two useful applications for virtual sensing technology. On the one hand, it is possible to prototype and foresee the effects of a new sensor on a robot swarm, before producing it. On the other hand, thanks to this technology it is possible to study the behaviour of robots operating in environments that are not easily reproducible inside a lab for safety reasons or just because physically infeasible. The use of virtual sensing technology for sensor prototyping aims to foresee the behaviour of the swarm enhanced with new or more powerful sensors, without producing the hardware. Sensor prototyping can be used to tune a new sensor or perform performance comparison tests between alternative types of sensors. This kind of prototyping experiments can be performed through the presented tool, that allows to rapidly develop and test software virtual sensors of different typologies and quality, emulating the behaviour of several hardware real sensors. By investigating on which sensors is better to invest, a researcher can minimize the sensors’ production cost while achieving a given swarm performance. Through augmented reality, it is possible to test the performance of the swarm in a desired virtual environment that cannot be set into the lab for physical, logistic or economical reasons. The virtual environment is sensed by the robots through properly designed virtual sensors. Virtual sensing technology allows a researcher to quickly carry out real robots experiment in challenging scenarios without all the required hardware and environment.