Design and evaluation of a flexible framework for collaborative virtual environments

Collaborative Virtual Environments (CVEs) are distributed virtual reality systems that allow multiple geographically distant users to communicate with each other and interact with virtual objects in a shared virtual world. Recently, there has been a growing interest in the development and use of CVEs. The design analysis of CVE systems reveals several critical technical issues: managing consistent distributed information, controlling access to objects by multiple users, supporting large number of users, handling new users joining an existing shared environment, and representing users to each other in the environment appropriately. As a result, various CVE systems have been developed to address these issues. Most existing systems are either focused on specific collaboration features or customized to particular range of target applications, which constrains the flexibility of the system architecture to support a wider range of applications and limits its extensibility to respond to new requirements. This document presents a design framework that addresses all of these major issues associated with CVE design and implementation, and a flexible open prototype implementation of this framework that explicitly exposes each of them, making evaluation of the effects of specific issues on overall system performance possible. A systematic approach to evaluation of whole system is proposed and applied through a focus on internal system characterization and a focus on the external effects of specific issues on system performance. The experimental results showed that the prototype system provides efficient performance for collaborative applications with respect to the requirements considered in the experiments. The evaluation of our prototype implementation shows that our approach is feasible, and can be applied for the evaluation of other instances of issues.