Real-Time Design Patterns in Virtual Simulations

Abstract

In a virtual simulation, people and real system hardware interact with the simulated system. Introducing these real-world elements into the simulation environment imposes timing constraints which, from a software standpoint, places the design into the class of real-time systems. We develop two software design patterns for real-time virtual simulations: a variant of the model-view-controller architecture and a companion component pattern that facilitates the development of hierarchical simulation models, graphical displays, and network input/output (I/O ) that meet real-time constraints. These design patterns promote good programming practice and allow the performance of a design to be evaluated using rate mono-tonic analysis techniques.

We also introduce selective abstraction and focused fidelity to reduce simulation development time and cost, while simultaneously improving runtime performance and the validity of simulation results.

Key Words:

• Virtual
• simulation
• real-time
• hierarchical modelling
• components
• rate monotonic

Additional information

Notes on contributors

D. Hodson

Douglas D. Hodson is the Analysis Branch Chief for the Air Force Simulation and Analysis Facility at Wright-Patterson AFB. He has over 20 years of experience in the domain of modeling and simulation and is the technical lead for the Extensible Architecture for Analysis and Generation of Linked Simulations (Eaagles) software framework. He is also the project leader for the spin-off open-source OpenEaagles development effort. He received a B.S. in Physics from Wright State University in 1985, and both an M.S. in Electro-Optics in 1987 and an M.B.A. in 1999 from the University of Dayton. He completed his Ph.D. in Computer Engineering at the Air Force Institute of Technology in 2009. His research topic characterized the consistency of shared simulation state data in terms of its temporal properties to estimate Live-Virtual-Constructive and Distributed Virtual Simulations performance.

R. Baldwin

Rusty O. Baldwin is an associate professor of Computer Engineering in the Department of Electrical and Computer Engineering, Air Force Institute of Technology, Wright-Patterson AFB, OH. He received a B.S. degree in Electrical Engineering (cum laude) from New Mexico State University in 1987, an M.S. degree in Computer Engineering from the Air Force Institute of Technology in 1992, and a Ph.D. degree in Electrical Engineering from Virginia Polytechnic Institute and State University in 1999. He served 23 years in the United States Air Force. He is a registered Professional Engineer in Ohio and a member of Eta Kappa Nu, and a Senior Member of IEEE. His research interests include computer communication networks, embedded and wireless networking, information assurance, and reconfigurable computing systems.

D. Gehl

David P. Gehl is employed by L-3 Communications, Link Simulation and Training Division. He has over 30 years of experience in man-in-the-loop simulation and training for human factors engineering research including extensive knowledge in pilot/operator-vehicle interfaces, aircraft system models (aerodynamics, radars, weapon delivery, navigation, visual systems, etc.), and real-time system development. He serves as the primary architect for the Extensible Architecture for the Analysis and Generation of Linked Simulations (Eaagles ) simulation framework. He holds a B.S. degree in Computer Science in 1979 and a M.S. degree in Systems Engineering in 1986 from Wright State University.

J. Weber

John G. Weber is a Professor of Electrical and Computer Engineering at the University of Dayton. He has over 35 years of industrial experience in the design and development of embedded computer systems for digital avionics applications. He also developed real-time, hardware-in-the-loop simulations in support of the development and testing of digital avionics systems. He received a B.S. degree in Electrical Engineering in 1963 from St Louis University, an M.S. degree in Electrical Engineering in 1964 from the University of Missouri-Columbia, and a Ph.D. in Electrical Engineering from the University of Missouri-Columbia in 1971.

S. Narayanan

Sundaram Narayanan is professor and chair of the Biomedical, Industrial, and Human Factors Engineering Department at Wright State University and is the executive director of the Wright State Research Institute. He received his Ph.D. degree in industrial and systems engineering from The Georgia Institute of Technology, Atlanta, in 1994. His research interests are in the area of designing interactive systems to aid humans in performing cognitively complex tasks such as planning, information retrieval and synthesis, and troubleshooting. His research has an interdisciplinary thrust with the following themes: cognition, computational representation, interactivity, and application. He has published over 75 technical articles and is associate editor of IEEE Transactions on Systems, Man, and Cybernetics, the International Journal of Modeling and Simulation, and Transactions of the Society for Computer Simulation. He is a fellow of the American Institute of Medicine and Biology in Engineering.