title = "A new formulation for symbolic regression to identify
physico-chemical laws from experimental data",
journal = "Chemical Engineering Journal",
year = "2020",
volume = "387",
pages = "123412",
month = "1 " # may,
keywords = "genetic algorithms, genetic programming, mixed-integer
nonlinear programming, MINLP, Model identification,
Chemical process development, Symbolic regression,
Automated model construction, Global optimization",
abstract = "A modification to the mixed-integer nonlinear
programming (MINLP) formulation for symbolic regression
was proposed with the aim of identification of physical
models from noisy experimental data. In the proposed
formulation, a binary tree in which equations are
represented as directed, acyclic graphs, is fully
constructed for a pre-defined number of layers. The
introduced modification results in the reduction in the
number of required binary variables and removal of
redundancy due to possible symmetry of the tree
formulation. The formulation was tested using numerical
models and was found to be more efficient than the
previous literature example with respect to the numbers
of predictor variables and training data points. The
globally optimal search was extended to identify
physical models and to cope with noise in the
experimental data predictor variable. The methodology
was proven to be successful in identifying the correct
physical models describing the relationship between
shear stress and shear rate for both Newtonian and
non-Newtonian fluids, and simple kinetic laws of
chemical reactions. Future work will focus on
addressing the limitations of the present formulation
and solver to enable extension of target problems to
larger, more complex physical models.",