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Previous issue date: 2007-08-23 / A collaborative virtual environment can be dened as a single virtual reality space hared by multiple participants connected from diferent hosts. However, most collaborative existing systems restrict the communication among the participants to text messages or audio communication. The natural means of human communication are richer than this. Other efects of coordinated visual and touch feedback play also a fundamental role and create a more realistic experience to the users. Motivated by the possibility of navigating and interacting remotely in a collaborative virtual environment, as well as simulating and sharing the perception of contact forces in diferent scenarios, an architecture for collaborative virtual environments for training, using force feedback devices, was designed, implemented and tested. The proposed architecture is composed of 4 components: the Device Manager, that makes possible the force feedback devices mapping; the Virtual Reality Environment, where the 3D application resides; the Collaboration Manager, that consists of a collaboration protocol for data sharing and controlling during the training sessions; and the Device Controller, responsible for the low-level routines needed to interact with the haptic device. The manager-type components, in particular improve the architecture _exibility and were implemented in such a way to be able to support extensions. To analyze the system performance, a significative number of experimental evaluations was conducted. The performance evaluations do not restrict themselves to the ideal environment conditions provided by a local area network, but also were applied to diferent network setups, where diferent bandwidth, delay and packet loss values were
simulated. Based on these experimental data, a similarity metric was dened to relate the processing time spent by the rendering process of the hosts (the masters that leads the training, and the trainee_s that follows the activities executed by the master) during the training exercise. The similarity values, obtained experimentally, were then compared to those obtained by a subjective analysis realized by the users. The results validated the architecture and demonstrated that the proposed methodology was useful to elaborate a detailed performance analysis of the system. Even in face of a wide variation in the processing times, obtained in nanoseconds, and consequently di_culty in the analysis of the packet loss impact on results, it was possible to successfully evaluate the efects of bandwidth and delay in the application performance, making use of similarity metrics that
varied according to a range of di_erent percentual values of tolerance. The definition of a rigid metric for the users' subjective analysis was also suitable, particularly for comparing the experimental results to the users' perceptions, in attempt to _nd out a possible range of trusting values for the tolerance parameters.
KEYWORDS: Performance Analysis . Collaborative Virtual Environment
Force Feedback . Training / A Televisão Digital está prevista para chegar à casa de muitos brasileiros em até dezoito meses após a liberação do pedido de concessão feito pelos radiodifusores. De imediato espera-se desta TV uma imagem em alta definição e suporte à multiprogramação. Em função deste último aspecto, a um curto prazo prevê-se uma demanda considerável da produção de conteúdo, visto que mais conteúdos serão necessitados. Além disto, prevê-se também uma mudança no modelo de negócios existente, imaginando-se que o conteúdo poderá ser criado usando diversas mídias (áudio, vídeo e dados) e tecnologias (como recursos da web), por diversas pessoas. Diante desta necessidade "anunciadora", este trabalho apresenta uma ferramenta para suportar a convergência da Televisão digital com a Web. Esta ferramenta permite aos usuários criarem seu conteúdo de forma rápida e simples usando um browser web e acessarem o conteúdo criado na Televisão Digital. A ferramenta apresentada foi utilizada para auxiliar no levantamento das necessidades, permitindo aos usuários tomar conhecimento das possibilidades da criação de conteúdo para a Televisão Digital. E, com os resultados obtidos a partir desta interação dos usuários, uma nova versão foi elaborada, levando em conta as opiniões e necessidades dos usuários.
| Identifer | oai:union.ndltd.org:IBICT/oai:dspace.unifor.br:tede/76636 |
| Date | 23 August 2007 |
| Creators | Soares, Pedro Henrique Seligmann |
| Contributors | Furtado, Maria Elizabeth Sucupira, Furtado, Maria Elizabeth Sucupira, Oliveira, Antônio Mauro Barbosa de, Gomes, Fernando Antônio de Carvalho |
| Publisher | Universidade de Fortaleza, Mestrado Em Informática Aplicada, UNIFOR, Brasil, Centro de Ciências Tecnológicas |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da UNIFOR, instname:Universidade de Fortaleza, instacron:UNIFOR |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 5443571202788449035, 500, 500, -7645770940771915222 |
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