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High Resolution Models using Monte Carlo. Measurement Uncertainty Research Group Marco Wolf, ETH Zürich Martin Müller, ETH Zürich Dr. Matthias Rösslein, Empa St. Gallen Prof. Walter Gander, ETH Zürich PTB-BIPM Workshop Impact of Information Technology in Metrology June 4 th 2007.
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High Resolution Models using Monte Carlo Measurement Uncertainty Research Group Marco Wolf, ETH Zürich Martin Müller, ETH Zürich Dr. Matthias Rösslein, Empa St. Gallen Prof. Walter Gander, ETH Zürich PTB-BIPM Workshop Impact of Information Technology in Metrology June 4th 2007
Outline • Introduction • Describing models with MUSE • Selected examples • Summary
Outline • Introduction • Describing models with MUSE • Selected examples • Summary
MUSE – Measurement Uncertainty Simulation and Evaluation • Software package for evaluation of measurement uncertainty • Currently developed at ETH Zürich in cooperation with Empa St. Gallen • Based on first supplement of GUM • Available from project page http://www.mu.ethz.ch for • Linux/Unix • Windows
Uncertainty Measurement Evaluation • Analytical Solution • Only applicable in simple cases • Even then it gets too complicated
Uncertainty Measurement Evaluation • Analytical Solution • Only applicable in simple cases • Even then it gets too complicated • GUM Uncertainty Framework • Applicable in many cases • Does not use all information • Needs linearized model • Ambiguous calculation of degrees of freedom
Uncertainty Measurement Evaluation • Analytical Solution • Only applicable in simple cases • Even then it gets too complicated • GUM Uncertainty Framework • Applicable in many cases • Does not use all information • Needs linearized model • Ambiguous calculation of degrees of freedom • Monte Carlo Method • Always applicable • Arbitrary accuracy • Uses all information provided for input quantities
Outline • Introduction • Describing models with MUSE • Selected examples • Summary
Modeling Measurement Equipment • Models of measurement equipment • Basic Models can be instantiated abritrary often • Using different sets of parameters • Database of Basic Models • Equivalent models allow global and direct comparison of results
Describing Measurement Procedure using Processes • Using instances of Basic Models together with other processes • Processes encapsulate their own settings for each instance or other processes • Splitting of description of devices and measurement scenario • Dependencies can be modeled by connecting processes
Definition of Calculation Parameters Random number genenerator Adaptive MC Number of simulations Variation • Random number generator • Options for adaptive Monte Carlo • Settings for self-validation • Settings for analyzing data files • Global variables and variation settings • Equation(s) of the measurand(s) Validation Variables Analyzing
Adaptive MC Numberofsimulations Variation Variables Validation Analysation Combination for Measurement Scenario Instances of Basic Models Process definition Calculation Section
Outline • Introduction • Describing models with MUSE • Selected examples • Summary
Example: Gauge Block Calibration • From GUM Supplement 1, section 9.5 • Shows difference of results of MC and GUM uncertainty framework • Model equation with following distributions: • Normal • Arc sine (U-shaped) • Curvelinear trapezoidal • Rectangular • Student-t
Example: Gauge Block Calibration * in 1/nm
Example: Chemical experiment • More complex scenariousing processes • Splitting the model equation into three parts: • Creating stock solution sols • Creating first solution sol1 • Creating second solution sol2 sols sol1 sol2
Example: Chemical experiment What is the difference if we use the same pipette?
Example: Measurement series • More than one formula for measurement uncertainty • More complex evaluation of the overall measurement uncertainty in a measurement series • Simulation of different measurement scenarious and strategies for analysing
Outline • Introduction • Describing models with MUSE • Selected examples • Summary
Summary • The examples show some features of the software and that the software is capable of handling high resoluted models • MUSE is under continuous development. It is thought for advanced users who want to analyze their uncertainty budget in detail • Current work: • Calibration • Module to analyze results • Simplification of definition of measurement series • Parallel computing
Thank you! Contact us directly or writeto: muse@inf.ethz.ch Homepage: www.mu.ethz.ch