Secondary abstract: |
The process of establishing an acceptable model of
an observed dynamic system from measured data is
a challenging task that occupies a major portion
of the work of the mathematical modeler. In this
thesis, we propose a knowledge-based approach to
automated modeling of dynamic systems based on
equation discovery methods.
Most work in equation discovery is concerned with
assisting the empirical approach to modeling physical
systems. Following this approach, the observed system
is modeled on a trial-and-error basis to fit observed
data. None of the available domain knowledge about the
observed system (or a very limited portion thereof) is
used in the modeling process. The empirical approach
contrasts with the theoretical approach to modeling,
in which the basic physical processes involved in the
observed system are first identified. A human expert
then uses domain knowledge about the identified
processes to write down a proper structure of the
model equations.
The equation discovery methods presented in the thesis
deal with the problem of integrating the theoretical and
empirical approaches to modeling of dynamic systems by
integrating different types of theoretical knowledge in
the discovery process. Two different types of
domain-specific modeling knowledge are considered herein.
The first concerns basic processes that govern the behavior
of systems in the observed domain. The second concerns
existing models that are already established in the domain.
In addition, the scope of the existing equation discovery
methods is extended toward the discovery of partial
differential equations that are capable of modeling both
temporal and spatial changes of the state of the observed
system.
The newly developed methods are successfully applied to
different tasks of modeling real-world systems from
artificial and real measurement data in the domains of
population dynamics, neurophysiology, classical mechanics,
hydrodynamics, and Earth science. |