Doing Time: Putting Qualitative Reasoning on Firmer Ground

e.g., digital, quantitative, qualitative or symbolic abstractions). In addition, it provides a framework in which to explore Recent work in qualitative reasoning has focused on predicting the dynamic behavior of continuous physical systems. Significant headway has been made in identifying the principles necessary to predict this class of behavior. However, the predictive inference engines based on these principles are limited in their ability to reason about time. such tasks as prediction, explanation, diagnosis[4], and design. I begin with a summary of current qualitative reasoning systerns and their limitations. Based on these limitations, a more robust language for describing behavior over time is presented. Next, an inference mechanism, referred to as a Temporal Constraint Propagator (TCP), is introduced ; TCP predicts the behavior of the desired class of systems in terms of the behavioral language. Finally, the power of this approach is demonstrated with an example taken from qualitative reasoning. 2 Qualitative Reasoning In A Nutshell Given a description of a physical system and its initial conditions, qualitative analysis typically involves 1) describing the temporal behavior of the system’s state variables, in terms of a particular This paper presents a general approach to behavioral prediction which overcomes many of these limitations. Generality results from a clean separation between principles relating to time, continuity, and qualitative representations. The resulting inference mechanism, based on propagation of constraints, is applicable to a wide class of physical systems exhibiting discrete or continuous behavior, and can be used with a variety of representations (e.g., digital, quantitative, qualitative or symbolic abstractions). In addition, it provides a framework in which to explore a broad range of tasks including prediction, explanation,ions). In addition, it provides a framework in which to explore a broad range of tasks including prediction, explanation, diagnosis, and design.