OOPM/RT: a multimodeling methodology for real-time simulation

When we build a model of real-time systems, we need ways of representing the knowledge about the system and also time requirements for simulating the model. Considering these different needs, our question is “How can we determine the optimal model that simulates the system by a given deadline while still producing valid outputs at an acceptable level of detail?” We have designed OOPM/RT (Object-Oriented Physical Modeler for Real-Time Simulation) methodology. The OOPM/RT framework has three phases: (1) Generation of multimodels in OOPM using both structural and behavioral abstraction techniques, (2) Generation of AT (Abstraction Tree) which organizes the multimodels based on the abstraction relationship to facilitate the optimal model selection process, and (3) Selection of the optimal model that guarantees the deliver simulation results by the given amount of time. A more-detailed model (low abstraction model) is selected when we have enough time to simulate, while a less-detailed model (high abstraction model) is selected when the deadline is immediate. The basic idea of selection is to trade structural information for a faster runtime while minimizing the loss of behavioral information. We propose two possible approaches for the selection: an integer-programming-based approach and a search-based approach. By systematically handling simulation deadlines while minimizing the modeler's interventions, OOPM/RT provides an efficient modeling environment for real-time systems.