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Education

September 2002 - October 2006

October 1997 - May 2002

## Publications

Publications (39)

The aim is to demonstrate the reliability of a population at consecutive points in time, where a sample at each current point must prove that at least 100% of the devices function until the next point with a probability of at least . To test the reliability of the population, we flexibilise standard lifetime models by allowing the unknown parameter...

According to ISO/IEC 17025:2017 statements of conformity must identify the decision rule applied, they must be risk-based and account for uncertainty. In legal metrology and often among testing and calibration laboratories, there is the need to reuse measurement-based conformity statements to disseminate acceptability of measurement results. In par...

Inhalt Vorwort 1 Teil I: Messunsicherheit praxisgerecht bestimmen Mechanische Messgrößen Der Einfluss der Reproduzierbarkeit auf die Messunsicherheit bei der Kalibrierung von Drehmomentaufnehmern nach Referenzprinzip 3 Planck-Erweiterung für hochgenaue Vakuum-Massekomparatoren – Ein Konzeptnachweis 17 Konformitäts- oder Nichtkonformitätsnachweis mi...

Following the Guide to the expression of uncertainty in measurement (GUM), the slope and intercept in straight-line regression tasks can be estimated and their uncertainty evaluated by defining a measurement model. Minimizing the weighted total least-squares functional appropriately defines such a model when both regression input quantities (X and...

In this document, the examples illustrate various aspects of uncertainty evaluation and the use of uncertainty statements in conformity assessment. These aspects include, but are not limited to
– choice of the mechanism for propagating measurement uncertainty,
– reporting measurement results and measurement uncertainty,
– conformity assessment, and...

This set of examples addresses measurements relating to industrial and societal requirements. The examples show improved and alternative treatments of the evaluation of measurement uncertainty, building on current practice in these areas. There is a need in the aerospace industry for calculations relating to quantities that are not directly measura...

This set of examples addresses measurement in healthcare in the following topic areas. The examples show improved and alternative treatments of the evaluation of measurement uncertainty, building on current practice in these areas. A diversity of topics is addressed, such as uncertainty arising in image reconstruction, determination of nanoparticle...

This set of examples addresses the calculations required in the energy sector in the following topic areas. The examples show improved and alternative treatments of the evaluation of measurement uncertainty, building on current practice in these areas. A diversity of topics is addressed, such as totalisation of fluids (water, natural gas) and energ...

Calibration examples in this collection relate to pH, mass spectrometry, mass measurement and unstable (drifting) reference materials. A testing example concerns the reaction of a test item to
adverse fire conditions. Comparison examples relate to (i) gauge blocks and the underpinning of calibration and measurement capabilities, and (ii) linking of...

Millions of measuring instruments are verified each year before being placed on the markets worldwide. In the EU, such initial conformity assessments are regulated by the Measuring Instruments Directive (MID). The MID modules F and F1 on product verification allow for statistical acceptance sampling, whereby only random subsets of instruments need...

It is shown that when X follows a location-scale distribution with continuous density function that has support R and 0<q<p<1, then P(|X|≤Δ)≥q implies P(|X|≤λΔ)≥p for some λ>1 and all values of the location and scale parameters. An explicit expression for the minimum λ is proven for the family of scaled and shifted t-distributions.

In metrology, the normal distribution is often taken for granted, e. g. when evaluating the result of a measurement and its uncertainty, or when establishing the equivalence of measurements in key or supplementary comparisons. The correctness of this inference and subsequent conclusions is dependent on the Normality assumption, such that a validati...

In practice, measurement results are sometimes described by an estimate, which is not the best one as defined in the GUM . Such alternative estimates arise when the result of a measurement is not corrected for all systematic effects. No recommendation exists in the GUM for associating an uncertainty with an uncorrected estimate.
A common choice in...

OIML Guide 20 [1] states that the key elements of metrological quality control for utility meters are initial verification, followed by subsequent verification at periodic intervals.
Focusing on subsequent verification, the PTB has developed a procedure that guarantees with high confidence that 95 % of the measuring instruments fulfil conformance...

The inspection of measurement devices according to statistical sampling plans allows conclusions to be drawn about the reliability of a whole population of devices. However, confirming high reliability levels requires large sample sizes and is thus expensive or even infeasible. For example, a reliability of 99.5% can only be guaranteed with 90% con...

Ensuring measurement trueness, compliance with regulations and conformity with standards are key tasks in metrology which are often considered at the time of an inspection. Current practice does not always verify quality after or between inspections, calibrations, laboratory comparisons, conformity assessments, etc. Statistical models describing be...

When the Guide to the Expression of Uncertainty in Measurement (GUM) and methods from its supplements are not applicable, the Bayesian approach may be a valid and welcome alternative. Evaluating the posterior distribution, estimates or uncertainties involved in Bayesian inferences often requires numerical methods to avoid high-dimensional integrati...

Regression is a common task in metrology and often applied to calibrate instruments, evaluate inter-laboratory comparisons or determine fundamental constants, for example. Yet, a regression model cannot be uniquely formulated as a measurement function, and consequently the Guide to the Expression of Uncertainty in Measurement (GUM) and its suppleme...

Immunoassays are capable of measuring very small concentrations of substances in solutions and have an immense range of application. Enzyme-linked immunosorbent assay (ELISA) tests in particular can detect the presence of an infection, of drugs, or hormones (as in the home pregnancy test). Inference of an unknown concentration via ELISA usually inv...

The CCQM study P58.1 assessed the equivalence of immunoassay measurements between participating NMIs. The aim of P58.1 was to demonstrate the equivalence of immunoassay measurements to determine the mass concentration of the clinically-relevant protein human cardiac troponin I (cTnI) present at low concentration relative to the protein concentratio...

A multi-center study has been set up to accurately characterize the optical properties of diffusive liquid phantoms based on Intralipid and India ink at near-infrared (NIR) wavelengths. Nine research laboratories from six countries adopting different measurement techniques, instrumental set-ups, and data analysis methods determined at their best th...

The European Metrology Research Programme (EMRP) is currently funding project EMRP- NEW04 on novel mathematical and statistical approaches to uncertainty evaluation. One focus of the project is uncertainty evaluation in the context of regression and parametric inverse problems. The development of methods for such problems will be carried out in clo...

In this paper, we extend a recently proposed procedure for the analysis of key comparison data to the case where the traveling standard shows a linear drift. The procedure is based on a fixed effects model and assumes that a certain number of the laboratories measure without bias. The analysis is carried out by applying Bayesian model averaging to...

The multivariate Gaussian model is frequently applied in metrology and many other fields. Notably, the recent Supplement 2 to the GUM (an extension of GUM and GUM S1 to multivariate problems) makes extensive use of multivariate normal distributions. Frequently, the mean and the covariance of this distribution have to be estimated from observations....

Intrinsic reduced scattering coefficient of Intralipid and intrinsic absorption coefficient of Indian ink at NIR wavelengths are accurately assessed in a multi-center study involving different techniques, instrumental set-ups, and analysis methods.

Let us analyse a measurement problem, where an unstable measurand is measured at ni different times — each time by (the same set of) nj devices or laboratories. The aim is to characterise the variabilities of the devices uncoupled from the variability of the measurand.
We will formulate this measurement problem as a heteroscedastic linear mixed mo...

Valuable information about the environment and climate of the past is preserved in ice cores which are drilled through ice sheets in polar and alpine regions. A pivotal part of interpreting the information held within the cores is to build ice core chronologies i.e. to relate time to depth. Existing dating methods can be categorised as follows: (1)...

Immunoassays are biochemical tests applied to measure even very small amounts of substance using the highly specific binding between an antibody and its antigen. They have a wide range of applications. The measurement however, might be associated with substantial uncertainty; this can have significant consequences for any diagnosis, or clinical dec...

Like all palaeoclimate reconstructions, those based on properties of ice cores rely on the construction of good chronologies. An obvious method for constructing such chronologies involves identifying and counting annual layers in the core; however this is only applicable where suitable high-resolution data exist. Chronologies based on glaciological...

Tooth Cementum Annulation (TCA) is an age estimation method carried out on thin cross sections of the root of mammalian teeth. Age is computed by adding the tooth eruption age to the count of annual incremental lines which are called tooth rings and appear in the cementum band. The number of rings is computed from an intensity (gray scale) image of...

Tooth Cementum Annulation (TCA) images are microscopic images from the root of human teeth. These digital images display annual incremental lines which can be used for age estimation. Until now, the incremental lines (or tooth rings) have been counted manually from under the microscope or on the (digital) TCA image. Since research using the manual...

Tooth Cementum Annulation (TCA) is an age estimation method carried out on thin cross sections of the root of human teeth. Age is computed by adding the tooth eruption age to the count of annual incremental lines that are called tooth rings and appear in the cementum band. Algorithms to denoise and segment the digital image of the tooth section are...

In the present paper, we will prove by an exhaustive search method that a pairwise balanced design on 30 points with blocks of size 4,5,7 and exactly one block of size 8 does not exist. © 2004 Wiley Periodicals, Inc. J Combin Designs 12: 271–278, 2004.