Linear constrain relations in biochemical reaction systems III. Sequential application of data reconciliation for sensitive detection of systematic errors

Abstract

This article presents a method to test the presence of relatively small systematic measurement errors; e.g., those caused by inaccurate calibration or sensor drift. To do this, primary measurements-flow rates and concentrations-are first translated into observed conversions, which should satisfy several constraints, like the laws of conservation of chemical elements. This study considers three objectives: 1.Modification of the commonly used balancing technique to improve error sensitivity to be able to detect small systematic errors. To this end, the balancing technique is applied sequentially in time.2.Extension of the method to enable direct diagnosis of errors in the primary measurements instead of diagnosing errors in the observed conversions. This was achieved by analyzing how individual errors in the primary measurements are expressed in the residual vector.3.Derivation of a new systematic method to quantitatively determine the sensitivity of the error, is that error size at which the expected value of the chisquare test function equals its critical value.The method is applied to industrial data demonstrating the effectiveness of the approach. It was shown that, for most possible error sources, a systematic errors of 2% to 5% could be detected. In given application, the variation of the N-content of biomass was appointed to be the cause of errors. (c) 1994 John Wiley & Sons, Inc.

On‐line stoichiometry and identification of metabolic state under dynamic process conditions

“…In contrast, the method proposed here uses the combination of all signals for calculating elemental balances and tests the consistency of the data using different stoichiometry based on statistical criteria, similar to those serving for the detection of systematic errors in measurements (van der Heijden et al, 1994c). For differentiating oxidative and oxido-reductive growth the measurements are tested for consistency by 2 -test using first a stoichiometric equation, including the overflow metabolites such as written in Eq.…”

Propagation of measurement accuracy to biomass soft-sensor estimation and control quality

“…In a previous approach, the uncertainty of turnover rates was approximated by propagation of variance [19]. However, under industrial applications, the maximal expected error is provided or known as an empirical parameter.…”

“…They highly depend on the accuracy of the raw signal measurements and dynamically change over time. Previously, this was approximated by propagating the variance of measurement accuracies to the turnover rates [19]. However, commonly, the expected or maximal error on measurement signals is provided by device manufacturers.…”

Metabolic Flux Analysis of Mammalian Cells

“…DNA and RNA (reaction [24][25][26][27][28][29][30][31][32][33][34]: DNA and RNA are assumed to consist of 10 nucleotides with a G:C:A:T ratio of 2:2:3:3.…”