Model-based reasoning: troubleshooting

We survey the current state of the art in model-based reasoning, particularly its application to diagnosis and troubleshooting, reviewing areas that are well understood and exploring areas that present challenging research topics. We conclude that diagnostic reasoning from a model is reasonably well understood, but that there is a rich supply of research issues in the modeling process itself. In a sense we know how to do model- based reasoning; we don''t know how to model the behavior of complex devices, how to create models, and how to select the ``right'''' model for the task at hand.