Effect of Synchronization on Bilinear Batch Process Modeling

There
is a widespread assumption that batch synchronization is
only required if the batch trajectories have different duration. This
paper is devoted to demonstrate that synchronization is a critical
and necessary preliminary step to bilinear batch process modeling,
no matter whether batch trajectories have equal length or not. Another
practical assumption is that all batches need the same synchronization
method to be aligned. Two different synchronization approaches are
compared in terms of synchronization quality: the Multisynchro approach
that takes into account the type of asynchronism and the method based
on linearly expanding and/or compressing pieces of variables trajectories
(the TLEC method), implemented in commercial software. The consequences
of inappropriately synchronizing batch data with multiple asynchronisms
in process monitoring are investigated. For this study, the observationwise
unfolding-T scores batchwise unfolding (OWU-TBWU) approach, which
integrates the TLEC method for batch synchronization, is used for
process modeling. Data from realistic simulations of a fermentation
process of the Saccharomyces cerevisiae cultivation with five different types of asynchronism are used for
illustration.