Integrating multiple representations for incremental, causal simulation

Many engineering problems require the ability to answer `what if´ questions about the effects of complex physical events. To address such problems, the author has implemented MIDAS, a system that can incrementally simulate events and produce causal explanations describing their effects. MIDAS incorporates an explicit causal model of time, change, and persistence. It integrates multiple specialized representations using a truth maintenance system that records belief justifications and enables incremental assertion and retraction of beliefs. MIDAS has been tested in several complex domains, including geology and semiconductor fabrication