Article by: Robert Lutz and Sean Murphy (Robert.Lutz@jhuapl.edu)
The National Space Biomedical Research Institute (NSBRI) has sponsored a research program over the past three years intended to demonstrate the ability to simulate integrated human function over time. The specific goal was to verify that interoperable simulations of human physiological functions applicable to the spaceflight environment, executing interactively, can produce integrated results that cannot be produced by these same simulations executing independently. Over the duration of this project, extensive experience has been accumulated working with the IEEE 1516 specification. This experience includes porting the four-federate, CardioVascular-Ventricular System (CVVS) Federation, originally written to comply with the DoD HLA V1.3 specification, to IEEE 1516 (02S-SIW-012). This experience also includes the generation of two new federations written under IEEE 1516; the significantly more complex Exercise Federation (ExerFed) that models the human response to exercise (03S-SIW-092) and a test myocyte federation that examines very large scale distributed computing.
Through creating all three federations, all six RTI service groups - Federation Management, Declaration Management, Object Management, Ownership Management, Time Management, and Data Distribution Management – have been exercised across programming languages and platforms. All federates in the myocyte federation were written in Java and can therefore be executed on any platform with a Java virtual machine. Both the CVVS and ExerFed federations however, involve federates written in C++ as well as federates written in Java. Similarly, both federations involve cross platform execution in that some federates run on a Windows PC while others are executed in Linux.
This paper (see link below) details the experience of using each service group, including problems that were overcome. It is not intended as an exhaustive treatment of the HLA services. Rather, it is intended as a practical tutorial for creating federates that use any of the six RTI service groups and as a lessons learned document to accelerate the development of IEEE 1516-based federates and federations. After the paper’s introduction, the first section overviews the IEEE Standard for Modeling and Simulation (M&S) High Level Architecture (1516 – 1516.3) and the service categories supported by the RTI. The next six sections contain the heart of the paper, discussing both the intent of each RTI service group and their detailed use in an actual federation. Due to paper length and experience limitations, not every single service in each group is discussed. However, the C++ and Java code sprinkled throughout the text (which was pulled from federate source files) demonstrates enough RTI service usage to guide the creation of a practical federation. Finally, we describe the software architecture of federates developed both in Java and C++ and their behavior during a typical federation execution.
To view the entire paper visit: www.sisostds.org/doclib/doclib.cfm?SISO_RID_1005465
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