Difficulties with true interoperability in modeling & simulation

Abstract

Interoperability among distributed models and simulations is complex, tedious and difficult to evaluate. Integrating models that were developed for various purposes with disparate technologies and managed by independent organizations is often the goal. This goal is underestimated due to misleading facts of commonalities between those applications. Common compliance with middleware architectures, modeling goals and even object models gives a false impression of complete interoperability. There are numerous considerations when developing a distributed simulation environment. The event's objectives drive the necessary simulation functions, but how those simulation functions interact needs to be meticulously designed for true interoperability. The semantics of the information transmitted, the behavior necessary across multiple applications, fidelity and resolution synchronization are only a subset of the systems engineering necessary for a coherent System of Systems. This paper covers interoperability complexities and proposes criteria to consider when developing, integrating and executing a distributed modeling and simulation architecture. BACKGROUNDTechnical integration frameworks evolve quickly. The technical leaders in the distributed modeling and simulation (M&S) industry cannot agree on the best technical path forward at any given time. Each program that develops a model or simulation has a specific purpose, set of requirements and limited funding. These programs cannot afford to coordinate with the entire industry to provide the most "interoperable" product. Even if they did meet with everyone to gather interoperability requirements, the task list would be too large to execute with limited funding. In some cases, the requirements would be mutually exclusive in the eventual implementation. The program offices should budget for and plan for coordination across domain projects within a limited scope to improve interoperability with those applications that are most appropriate, but the utopian goal of cross-Service and cross-domain interoperability cannot be solved by funding alone. We work on an Army project that has integrated dozens of models into a single System of Systems architecture. These models have a wide range of purposes, fidelity, resolution, managing organizations and technologies. The topics covered herein are inspired by lessons learned on this project, as well as our collaboration with many other efforts in the M&S community. INTEROPERABILITYInteroperability, described most simply, is the ability for multiple systems to work together for a larger goal than any one system could provide on its own. Some simple examples of interoperability by two disparate components include USB drives made by a multitude of manufacturers working with a computer, cell phones made by different companies using different communication protocols being able to allow da-2637 978-1-4577-2109-0/11/$26.00 ©2011 IEEE