Temporal Uncertainty Time Warp: An Implementation Based on Java and ActorFoundry

Abstract

This article describes temporal uncertainty time warp (TUTW), a distributed control engine designed for exploitation of temporal uncertainty (TU) in general optimistic simulations. Novel in TUTW is an event model in which time intervals are attached to events instead of classical punctual or “precise” time stamps. All of this complies with system specifications where the occurrence time of events cannot be known with complete certainty. TUTW is able to take advantage of TU by resolving events in such a way as to reduce the number of rollbacks. The simulator performance can thus be improved without necessarily compromising the accuracy of the results. An agent-based implementation of TUTW was achieved that enables simulations to be carried out over the Internet. The implementation depends on Java and the ActorFoundry middleware. The implementation is totally portable and simplifies configuration and control of a distributed simulation virtual computer that includes heterogeneous computing platforms. The article reports performance and accuracy results of TUTW applied to a large QNET simulation model.