Critical causal order of events in distributed virtual environments

We investigate the causal order of events in distributed virtual environments (DVEs). We first define the critical causal order relation among the events. Then, we propose some mechanisms to enhance the prevalent RO (receive order delivery) mechanism in DVEs so that the real-time property of DVEs is preserved while the critical causal order violations are reduced. These mechanisms are implemented as a middleware. Experimental results show that the middleware performs well in reducing the critical causality violations in simulation and incurs little processing overhead.