Proposal of high level architecture extension and run-time infrastructure implementation

Abstract

The High Level Architecture (HLA) is an IEEE standard for interoperation between heterogeneous simulations, which are developed with different languages and platforms. The HLA is applied not only to the field of distributed simulation but also to various applications including virtual reality, voice over IP, networked games and other generic network applications. A lot of issues regarding security and performance have been raised from the experience of large-scale interoperation led by nations and organizations. The information hiding problem deals with regulation of information flow between simulators. This problem occurs when two or more federations under different authority merge together. In addition, the lack of message-level protocol specification in HLA prevents different RTI software talking each other. The performance of RTI software became a constant issue because it determines that of whole federation. The thesis proposes a three-dimensional extension of High Level Architecture specification to solve previous problems. The extension includes hierarchical architecture of federations, open RTI protocol, and user-extensible modular design of RTI software. The hierarchical structure of federations easily controls the flow of information between simulators, together with Simulation Object Model(SOM)-based join process. An open RTI protocol including message formats, their handling algorithms and message sequences is listed to enable interoperation between RTI software. The proposed modular architecture of RTI software describe RTI software as a set of interconnected modules, which are replaceable even at runtime. The modules are implemented using Discrete Event System Specification (DEVS) formalism, and its extension to commodate variable structure models.