EBSILON®Professional Online Documentation
EBSILON®Professional offers several possibilities for data validation:
This method has a low input effort and needs extremely low computing time. When the correlations are ignored and the weightage is excessive, it returns an estimation (not conforming to VDI 2048) for the most probable process state. The relative weights needed for this are estimated. In case an ensured validation calculation is to be done according to VDI 2048, it is also recommended to determine the relative uncertainties from the confidence intervals determined thereby and to use their return value as the weight. This can be automated with EbsScript. Since this method uses relative weights, it is not possible in this case to make statements about the confidence intervals of the validated values. As such, there is no evaluation for the calculated estimated values of the true values. If noteworthy correlations are present, then this method should not be used.
This method not only determines the most probable process state, but also permits specifications about the reliability of the validated values: for all measured and result values the 95%-confidence interval is shown. This means that the true value of this parameter lies within the specified range with a probability of 95%.
For calculating according to VDI 2048, two algorithms are present in EBSILON®Professional:
Normally the first algorithm is selected. The second is not recommended for the user owing to high computing time. We use this method only for comparison purposes in program development (checking through an independent second method).
Note ( Confidence intervals and weights )
The weights (WMV) of the measured values are used for the quick validation, and the confidence intervals (MCONF) are used for the validation according to VDI 2048. The specification value MCONF, though, was introduced as late as October 2003. However, it had been possible to carry out a VDI 2048 validation with Ebsilon prior to that, but for this the 1.96-fold of the reciprocal value of the confidence interval had to be entered for the weight.
For reasons of compatibility, up to Release 10 a blank value of MCONF was not reported as an error, but a confidence interval was calculated from the weight. Unfortunately, this led to misleading results in the case of confidence intervals left blank by mistake. For this reason, an error message is generated when the confidence interval is empty in a VDI 2048 validation.
Users who want to use models from the time before 2003 are asked to use the specification value MCONF.