Plausible Petri nets as self‐adaptive expert systems: A tool for infrastructure asset monitoring
This article provides a computational framework to model self‐adaptive
expert systems using the Petri net (PN) formalism. Self‐adaptive expert
systems are understood here as expert systems with the ability to
autonomously learn from external inputs, like monitoring data. To this
end, the Bayesian learning principles are investigated and also combined
with the Plausible PNs (PPNs) methodology. PPNs are a variant within
the PN paradigm, which are efficient to jointly consider the dynamics of
discrete events, like maintenance actions, together with multiple
sources of uncertain information about a state variable. The manuscript
shows the mathematical conditions and computational procedure where the
Bayesian updating becomes a particular case of a more general basic
operation within the PPN execution semantics, which enables the
uncertain knowledge being updated from monitoring data. The approach is
general, but here it is demonstrated in a novel computational model
acting as expert system for railway track inspection management taken as
a case study using published data from a laboratory simulation of train
loading on ballast. The results reveal self‐adaptability and
uncertainty management as key enabling aspects to optimize inspection
actions in railway track, only being adaptively and autonomously
triggered based on the actual learnt state of track and other contextual
issues, like resource availability, as opposed to scheduled periodic
maintenance activities.