“…In most of the approaches, the scalar measure is chosen to be the trace of the reconstruction error covariance matrix. The use of a scalar measure (usually the trace) of the steady-state covariance of the reconstruction error is borrowed from optimal sensor placement strategies proposed in structural dynamics applications for response reconstruction based on Kalman-type filter methods subjected to known loads [44][45][46]. The size of the reduction of the measure as a function of the number of sensors is used to select a reasonable number of sensors.…”