An Approach for Reasoning about Semiqualitative Models with Explicit Constraints


J. A. Ortega, R. M. Gasca, and M. Toro

Departamento de Lenguajes y Sistemas Informáticos. Universidad de Sevilla Avda. Reina Mercedes s/n. Sevilla (Spain)



Abstract: In our approach, a semiqualitative model of a dynamic system is expressed by means of a set of constraints among variables, parameters and intervals. The methodology [Ortega99] [Ortega00] was appropriate to simulate these non-causal semiqualitative models with constraints. Applying this methodology, a semiqualitative model was transformed into a family of quantitative models without explicit constraints. In this paper, the methodology is enriched to manage family of quantitative models where may be explicit constraints. The main idea of the proposed improvement is as follows: Given a non-causal semiqualitative model with constraints, it is rewritten into an equivalent model by means of the transformation of the qualitative knowledge. This non-causal model is expressed by means of a set of constraints where the states variables may be included. These constraints are ordered and transformed into an equivalent setofconstraints to apply the whole methodology. This new set represents a family of quantitative models with explicit constraints. This extended methodology is applied to an interconnected tank model with constraints.

Keywords: Semiqualitative models with constraints, Simulation and transformation


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