However, in spite of the unidentifiability of the individual parameters, the basic reproduction number was successfully estimated across the unidentifiable parameter ranges.
Using the measured activity in the ROI (C M (t)) and in blood (C B (t)), least square estimation of the five model parameters (K 1, k 2, k 3, V A, V B ) leads to problems of numerical unidentifiability.
The findings are explained in the context of an online sense of unidentifiability, which apparently requires a more refined view of the components that create a personal sense of anonymity.
Even in the case of structural (theoretical) identifiability, imperfect data and the resulting practical unidentifiability of model parameters can make it difficult to infer the desired information, and in some cases, to yield biologically correct inferences and predictions.
Because only parts of the data are considered, problems with parameter unidentifiability are exaggerated in STS.
Unique model predictions can in fact be obtained despite unidentifiability, as discussed by Cedersund [ 52].
In fact, the unidentifiability of these parameters implies infinite error bars have to be assigned to them.
Like unidentifiability, overfitting is common in large-scale systems biology models such as the ones presented here.
Although the parameters from the APC model cannot be interpreted due to unidentifiability, the related significance test remains appropriate.
We effectively deal with the issues of network scale, stiffness, local minima, computational burden and parameter unidentifiability inherent within a large MRL model.
One drawback of APC models is their inherent unidentifiability: P= A+ C. In practice, the identifiability problem can be resolved by considering only two-effects models, typically age period or age cohort.
