On time granularity and event granularity in simulation service composition (WIP)

There is an increasing need for systematic composition of simulation services in the emerging service-oriented computing environment. An important issue that hinders simulation service composition is the mismatch of granularity when coupling two services together. In this paper, we focus on time granularity and event granularity in composing simulation services at the pragmatic level. We identify and develop four types of granularity handling agents to be associated with the couplings between services. The developed method is illustrated by a coupled weather-wildfire simulation example. 1. INTRODUCTION In a service-oriented computing environment, there is a need to compose several simulation services in a way that the multiple simulation services are coupled together and dynamically influence each other. While simulation service composition shares many common properties of general web service composition, it has some unique features due to the fact that simulation services rely on dynamic models where time is important. This means individual simulation services in the composition must behave according to a common time base in order to ensure the correct temporal order of events. Research of simulation service composition has often been studied together with the topic of modeling and simulation interoperability. In particular, to help studying different issues arising in simulation interoperability, the Levels of Conceptual Interoperability Model (LCIM) were introduced, which identified seven levels of interoperability among participating systems [1]. A reformulation of LCIM was presented in [2, 3], which summarizes three linguistic levels of interoperability: Syntactic level, Semantic level, and Pragmatic level. In this paper, we adapt a maturity reference model for simulation service composition based on [2, 3], and focus on the pragmatic level which emphasizes on the rationality of the composition and the context of the simulation service behavior.