We describe a heterogeneous simulation framework, so called DEVS-HLA, in which
conventional simulation models and the DEVS (Discrete Event System Specification)
models are interoperable. DEVS-HLA conceptually consists of three layers: model layer,
DEVS BUS layer, and HLA (High Level Architecture) layer. The model layer has a
collection of heterogeneous simulation models, such as DEVS, CSIM, SLAM, and so on, to
represent various aspects of a complex system. The DEVS BUS layer provides a virtual
software bus, DEVS BUS, so that such simulation models can communicate with each
other. Finally, the HLA layer is employed as a communication infrastructure, which
supports several good features for distributed simulation. The DEVS BUS has been
implemented on the HLA!RTI (Run-Time Infrastructure) and a simple example of a
flexible manufactu꾀ng system has been developed to validate the DEVS-HLA.