Characterizing, Measuring, and Validating the Temporal Consistency of Live—Virtual—Constructive Environments

Abstract

A distinguishing characteristic of interactive live—virtual—constructive (LVC) environments is the relaxation of data consistency to improve the performance and scalability of the underlying distributed simulation. Relaxing data consistency improves the interactive performance of the environment because autonomous distributed simulation applications can continue executing and responding to local inputs without waiting for the most current shared data values. Scalability also improves since live and simulated entities from distant geographic locations can be interconnected through relatively high-latency networks. We introduce a temporal consistency model to formally define consistency for the dynamic shared state of a LVC environment for both continuous and discrete data objects. The level of inconsistency tolerated by a LVC is found to be a function of the accuracy and timeliness requirements for the distributed data objects. These requirements are mapped to specific time intervals for which data objects are considered valid. We also develop a real-time algorithm to compute the temporal consistency of individual data objects within the LVC.