Towards enhanced data consistency in distributed virtual environments

Distributed virtual environments are rapidly gaining in popularity for the implementation of intuitive and collaborative workspaces. In distributed virtual environments, geographically dispersed user sites possess considerable capabilities for computing and cooperation with other user sites. Primary challenges that have to be addressed by these systems are compensating network latency jitters, keeping system-wide data consistent, enabling fair resource sharing and interaction between the users. This paper reviews a global time-stamp based approach, which is developed by authors to enhance the fairness and consistency across the distributed virtual environments. The approach is described in combination with three different implementation philosophies, a centralized approach similar to client-server model, a decentralized approach similar to peer-to-peer model, and a combined approach consisting of hierarchical layers of centralized and decentralized approaches. Based on a new object-oriented real-time programming methodology called the time-triggered message-triggered object (TMO) programming scheme, two different implementations were tested and compared.