Distributed simulation using the virtual test bed and its real-time extension

Distributed simulation is desirable at many levels of system design. Modeling and simulation of large complex systems, remote monitoring and control, and nondestructive remote testing of devices are three examples of the many applications in which both distributed and realtime distributed simulation are advantageous. Distributed simulation reduces simulation complexity by allowing the partitioning of a large complex system into two or more smaller subsystems. In addition, distributed simulation permits computational resource sharing and enables teamwork. The Virtual Test Bed (VTB) and its real-time extension, VTB-RT, have been adapted to deal with distributed simulation in both non-real-time and real-time. Efforts at Mississippi State University and the University of South Carolina have made possible the addition of models for distributed simulation to the VTB model library to handle both natural and signal coupling at the decoupling point. The focus of these efforts has been on the algorithms used to enforce simulation stability and energy conservation in a distributed environment. Implementation issues related to the different communication architectures used in distributed simulation environments are only briefly discussed in this paper. The models for distributed simulation described in this paper are implemented using a simple remote procedure call communication scheme, which is sufficient to demonstrate the proposed algorithms. Several examples presented in this paper demonstrate the applicability and accuracy of the developed VTB models.