Qualitative Analysis of Discontinuous Changes in Simple Pulse Circuits

Abstract

Discontinuity is a useful notion in understanding the behavior of physical systems without warrying about unmotivated details. In this paper, we present a method of analyzing discontinuous changes at a commonsense level. We take simple pulse circuits as subject. The center of the method is an algorithm for predicting the behavior of given circuits in causal terms. Potential obstacle in developing this algorithm was that ordinary circuit equations lack sufficient information for causal analysis, resulting in ambiguity. To overcome this problem we assume discontinuous changes are very rapid continuous changes to choose a standard explanation from candidates. We also introduce the notion of mythical state to qualify intermediate stages of discontinuous change which does not satisfy circuit equation. The algorithm is fully implemented using Utilisp. This paper consists of three parts : we first overview the qualitative reasoning method which we base our algorithm on, we then study properties of discontinuous changes, and we present the algorithm. The solution to all examples shown in this paper is outlined in appendix.