Shared Variable Management in SOAr-DSGrid

Simulation is a low cost alternative to experimentation on real-world physical systems. In light of the prevalence of web services, issues relating to distributed simulation using web services have come to the fore in recent years. We have proposed a service-oriented architecture for distributed simulations on the Grid (SOAr-DSGrid). SOAr-DSGrid facilitates the development and execution of distributed simulations in different views (i.e., a component-based view for development and a service-oriented view for execution). At run time, one component may require information from another component for execution or decision-making. In SOAr-DSGrid, this shared information from one component to another component is implemented through shared variables. Since two components may execute out of phase, without proper shared variable management, the value provided by one component may be invalid for another component due to the time difference. Since SOAr-DSGrid provides a service-oriented view for component execution, the development of shared variable support also follows the service-oriented methodology. Three different approaches, namely Pull without FutureList, Pull with FutureList, and Push, have been implemented as the internal mechanism to solve the shared variable issue. Experimental results of the performance of these three approaches are also presented in this paper.