Measurement error Terms Links

It is now possible to introduce a second parameter E which measures the cross-link efficiency after treatment with the triphenyl phosphine. On the assumption that treatment causes all cross-links to become monosulphidic the term (E -l) provides a measure of the combined sulphur not in cross-links , e.g. in pendent groups or in intra-chain cyclic sulphides. If the reaction does not proceed beyond the disulphide stage then this measure is given by (E - 2). Whilst it is tempting to use E - (E - 1 or 2) as a measure of the average value of the number of sulphur atoms in a cross-link, Jc, there is a possible error due to the removal of sulphur from cyclic sulphides and pendent sulphides by the triphenyl phosphine. 

A diagnosis procedure based on evaluation of physical constraint laws derived from bond graph models is described here. Symbolically written constraints, called analytical redundancy relations (ARRs), are expressed in terms of known variables (measurements and inputs). ARRs are static or dynamic constraints which link the time evolution of the known variables when a system operates according to its normal operation model. The error or deviation from the constraint model is called a residual. The objective of quantitative diagnosis is to evaluate the residuals and associate the fault symptoms with deviations of residuals. 

These criteria are obviously interrelated. An excellent choice of a Pb-exposure biomarker on diagnostic or predictive grounds is only acceptable if it can be broadly applied and quantified in the biological medium of interest. Methodology for sampling and measurement must be sensitive, specific, and have steps that minimize random or systematic errors, such as random or systematic Pb contamination of samples. Exposure measurements which can be quantified must also be linked to dose—toxic response relationships and have a wide level of acceptance in terms of diagnostic, epidemiological, or forensic applicability. 

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