Combined Qualitative and Numerical Simulation with Q3°'

Daniel Berleant and Benjamin Kuipers Department of Computer Sciences University of Texas at Austin Austin, Texas 78712 To be submitted to AAAI-90 & the Qualitative Physics Worksho 1990 Topic: Common Sense Reasoning. Subtopic : Simulation. 2/1590. Abstract Combining numerical and qualitative simulation into one technique allows simulation to be performed even when there is insufficient information for a numerical simulation. Predictions are also guaranteed correct. Also, numerical simulations predict just one behavior ; combined simulations can predict more than one when this is warranted. Thus, combined simulation is an improvement over numerical simulation . Combined simulation is also an improvement over qualitative simulation. Qualitative simulation provides weak predictions, because it relies on weak model descriptions . Combined simulation allows adding numbers to model descriptions, resulting in stronger and potentially more practical predictions . Q3 is a system for doing combined simulation . It uses intervals to express partial information about values, because intervals can express values anywhere from fully specified numbers, to partially spec ified numbers, to very vague qualitative values . Q3 also explicitly represents qualitatively significant values, like qualitative simulation, and other values, like numerical simulation. Thus, Q3 represents, and reasons, in ways that neither numerical simulation nor qualitative simulation do alone.