  A test dataset is generated using temperature cycled operation with a WO3
metal oxide semiconductor (MOS) gas sensor. Six concentrations of naphthalene
from 0 to 40 ppb are measured and, subsequently, used to evaluate the
performance of three variants of Partial Least Squares Regression (PLSR).
Ordinary PLSR produces highly non-linear models due to the non-linear response
of the sensor. Double-logarithmic data results in a model with much better
linearity which has a resolution of 4 ppb in the range from 0 to 20 ppb. The
more complex Locally Weighted PLSR (LW-PLSR) produces an even better model,
especially for higher concentrations, without making any assumptions for
relationships in the underlying data.
