%A Jeff Rickel
%A Bruce Porter
%T Automated Modeling for Answering Prediction Questions: Selecting 
the Time Scale and System Boundary
%J AAAI-94
%P 1191-1198
%D 1994
%I AAAI/MIT Press
%C Cambridge, MA
%X The ability to answer prediction questions is crucial to reasoning
about physical systems.  A prediction question poses a hypothetical
scenario and asks for the resulting behavior of variables of interest.
Prediction questions can be answered by simulating a model of the
scenario.  An appropriate system boundary, which separates aspects of
the scenario that must be modeled from those that can be ignored, 
is critical to achieving a simple yet adequate model.  
This paper presents an efficient algorithm for system boundary
selection, it shows the important role played by the model's time
scale, and it provides a separate algorithm for selecting this time 
scale.  Both algorithms have been implemented in a compositional modeling
program called TRIPEL and evaluated in the plant physiology domain.
%X http://www.cs.utexas.edu/users/mfkb/papers/rickel-94.ps