The TeQSIM project
TeQsim (Temporally constrained Qsim), pronounced
tek'sim, is a qualitative simulator of dynamical systems. It is
an extension of the QSIM algorithm that incorporates behavioral information
in the form of trajectory constraints into the simulation process
to restrict and refine the resulting behavioral description.
Three types of trajectory constraints can be specified:
- external events: they denote time points
that mark interesting changes to some exogenous variable of the
model; in this way references to an absolute time-line is made possible
within the qualitative simulation;
- temporal logic constraints: a specification
(using a propositional linear-time temporal logic) of the admissible trajectories
of variables;
- discontinuous changes: a specification
of discontinuous jumps of input variables.
TeQsim was used to explore the following issues:
- for focusing the qualitative simulation to interesting
trajectories;
- to perform input driven qualitative simulations;
- to solve boundary conditions problems (like determining
initial velocity and direction of a projectile that has to follow a certain
trajectory and reach a target);
- to determine which values for parameters of a
continuous feedback controller may achieve a performance satisfying certain
requirements;
- to validate discrete control actions on continuous
plants.
The following papers describe TeQsim:
TeQsim was developed by Daniel
J. Clancy
and myself.
Most of the research has been performed within the Qualitative
Reasoning Group at the University of Texas.
TeQsim was available with the standard QSIM distribution.
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