1. A simulation system comprising: a simulation reference simulator ( 30 ) adapted to receive an SRML simulation model ( 32 ) including a simulation item ( 20 ), wherein said simulation reference simulator ( 30 ) comprises: an item manager ( 44 ) for loading properties of each item ( 20 ) of the simulation model ( 32 ); and an event manager ( 46 ) for processing the simulation model ( 32 ).