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M. Neumayer, D. Watzenig, G. Steiner
FAST ESTIMATION AND UNCERTAINTY QUANTIFICATION IN ELECTRICAL CAPACITANCE TOMOGRAPHY USING SURROGATE TECHNIQUES

The need for uncertainty quantification (UQ) in metrology has seen serious research efforts and is of ever-growing interest in order to quantify the quality of measurement results. This especially holds for indirect measurement problems. Bayesian methods allow a natural and universal access for UQ but become computationally expensive for scenarios with a complex interaction between the unknown quantity x and the raw measurements d. In this paper we present a surrogate approach for fast estimation and UQ of material distributions in the inverse problem of electrical capacitance tomography using a recursive Bayesian estimator.

G. Wimmer, V. Witkovský
TWO CALIBRATION MODELS

Analyzed is the comparative calibration problem in the case when linear relationship is assumed between two considered measuring devices. The first method for obtaining the approximate confidence region for unknown parameters of the calibration line applies the maximum likelihood estimators of the unknown parameters. The second method is based on estimation of the calibration line via replicated errors-in-variables model. Essential point in this approach is the use of the F-approximation of the distribution of the F-statistic suggested by Kenward and Roger (1997). The contribution shows also the interval estimators for the multiple-use calibration using both methods and enables to compare them.

A. Gunay, S. Fank, T. Gulmez, N. Durakbasa
CALCULATION OF MEASUREMENT UNCERTAINTY FOR PLASTIC (ABS) MATERIAL IN FLEXURAL TESTING

In order to determine mechanical properties of materials several tests can be applied by using their tensile strength, lower yield stress, proof stress, impact strength, Brinell, Rockwell and surface hardness, elongation after fracture properties. Among these tests, three point flexural testing method has some advantages such as for easy preparation (production) of samples and no gripping problems comparing to tension test. Flexural tests results should be known very well. The measurement uncertainty of flexural tests should be calculated adding the all-influencing parameters during tests. In this study, the measurement uncertainty of the flexural test of ABS (Acrylonitrile Butadiene Styrene) material was determined, which is widely used as industrial plastic material in many applications.

A.Chunovkina, N.Zviagin, N.Burmistrova
INTERLABORATORY COMPARISONS. PRACTICAL APPROACH FOR DATA EVALUATION

This paper deals with evaluation of inconsistent data from interlaboratory studies in case when reference value is known a priori. Applications of different methods for evaluating inconsistent data concerning this particular case are discussed. An explicit practical approach is proposed and illustrated by examples.

R. Palencár, S. Duriš
MATRIX INTERPRETATION OF THE UNCERTAINTY PROPAGATION FOR THE ITS-90 REALISATION

Matrix approach to the propagation of uncertainties in the temperature scale ITS-90 realisation based on the Guide to the Expression of Uncertainty in Measurement (GUM) and the Supplement 2 to the GUM. This approach allows to include the correlations between the SPRT resistances from calibration at the defining fixed points in the calculation. The contribution of correlation to the overall uncertainty is presented too.

Jankowski Piotr, Mindykowski Janusz
METROLOGICAL ASPECTS OF THE INDUCTIVE DYNAMIC DRIVE RESEARCH

The article is the synthetic description of the methods applied by authors to assign the quantities characterizing the proprieties of an inductive dynamic drive. The used measuring methods were divided as follows:
1) direct methods which make it possible to mark the searched quantities on the basis of direct observation of the tested measuring system,
2) indirect methods which use obtained results (in direct method) to determine the measured quantities.
Very often they require a more complex computer processing or even the use of mathematical models. The experimental registration of coil current and the disc displacement was classified as a direct method. The simulating determination of speed, the acceleration and the state of stress in the disc with the use of the coil current and the displacement were classified as an indirect method.

Claire Bartoli, M.Florian Beug, Thomas Bruns, Clemens Elster, Trevor Esward, Leonard Klaus, Andy Knott, Michael Kobusch, Sari Saxholm, Christian Schlegel
TRACEABLE DYNAMIC MEASUREMENT OF MECHANICAL QUANTITIES: OBJECTIVES AND FIRST RESULTS OF THIS EUROPEAN PROJECT

Nine European National Metrology Institutes (NMIs) are collaborating in a new project funded by the European Metrology Research Programme (EMRP) to establish traceable dynamic measurement of the mechanical quantities force, pressure, and torque.
The aim of this joint research project (JRP) is to develop appropriate calibration methods, mathematical models, and uncertainty evaluation. The duration of the project is 3 years for a global amount of €3.6 million. It began in September 2011.

A. B. Forbes
MEASUREMENT UNCERTAINTY AND SUMMARISING MONTE CARLO SAMPLES

Many uncertainty evaluation applications require summary information about the distribution associated with the measurand. This paper looks at summarizing distributions on the basis of Monte Carlo samples and describes how relative entropy can be used as a measure of the effectiveness of the summary.

C.Hernández, R.Tutsch
SAMPLING STRATEGIES AND LONG TERM VARIATION MODELLING FOR A STATISTICAL FEED-FORWARD CONTROLLER

The Statistical Feed-Forward Control Model (SFFCM) relies on a sequence of specification adjustments made on subsets of a population to counter the influence of the long time component of the variation. The difficulty strives in finding a proper estimate for the measure of the central tendency of each subset to minimize the number of the required adjustments. By means of simulating the assembly of two components having high dimensional variation, forty experiments were designed to compare the individual influence of different factors such as the number of adjustments, the sampling strategy and two measures of central tendency: the sample mean and the cumulative denoised average. Simulation results showed that, regardless of the sampling strategy but keeping the inspection rate at 20%, the use of the cumulative de-noised average instead of the sample mean made possible to reduce the number of adjustments by 20%. Thus, while the shift mean of the resulting assembly was decreased by 90%; the standard deviation was reduced by 15%. Hence, the selection of a proper central tendency measure is crucial when modeling the long time variation. The cumulative de-noised average proved to be a valid alternative.

Rossella Berni, Valeria L. Scarano, Marcantonio Catelani
EXPERIMENTAL DATA AND STATISTICAL MODELS FOR OPTIMIZATION OF AGEING MODEL OF LEAD-FREE ELECTRONIC INTERCONNECTION MATERIAL

Modelling and understanding the electrical ageing is a complex phenomenon, in particular for composite material as electrically conductive adhesive consisting of a nonconductive polymer binder and conductive filler particles. This research involves a large amount of parameters related to both operating conditions and material structure, which act together. Accelerated testing used in order to describe the ageing process and to determine the lifetime of these material are difficult to implement with the aim to consume rapidly lifetime without inducing incorrect failure mechanisms. Further difficulties are the implementation of the right chemico-physical ageing model for lifetime prediction under accelerated testing and new statistical approach for reliability data analysis and treatment.

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