IMEKO Event Proceedings

Page 789 of 822 Results 7881 - 7890 of 8218

A. R. Valdés, A. Piratelli-Filho, D. P. Vieira Sato
UNCERTAINTY OF COMPONENTS OF VOLUMETRIC ERRORS

The aim of the present work is to calculate the uncertainty associated with volumetric error components in a Moving Bridge type Coordinate Measuring Machine (CMM). Two methodologies are presented for this purpose. The first consisted in equationing the components of the volumetric error using homogeneous transformations techniques; measurement of the geometric errors and Abbé offsets; mathematical models regarding each geometric error and Abbé offset were written and the law of uncertainty propagation was applied. The second methodology present simplified models to estimate the measurement uncertainty associated with volumetric error component, identifying the variables that influence the determination of geometry deviations, development of a mathematical model for the volumetric error components, development of a routine to evaluate uncertainty. It was concluded that the simplified models are adequate and easy to be applied. As conclusions, the components of volumetric error of X, Y and Z axes present uncertainty values close to 2.7, 4.0 and 2.0 mm, respectively.

F. Corrêa Alegria, A. Cruz Serra
UNCERTAINTY OF ESTIMATES OBTAINED WITH THE HISTOGRAM TEST OF ADCS

We present here expressions to determine the uncertainty interval of the estimates of transition voltages and code bin widths of an analogue to digital converter obtained with the Standard Histogram Test. We consider the presence of additive noise as it influences the precision and causes a bias on the test results.

Zhijie Zhang, Wei Wang, Wenlian Wang, Daihua Wang
UNCERTAINTY OF MEASUREMENT OF TRANSIENT PRESSURE

The measurement of air shock wave pressure is a typical problem of transient measurement. Because the measurement data in many cases is used to judge the quality of a product, or as a basis for changes being made during a development phase, uncertainty analysis or assessment of measurement data takes a very important role in the process of reporting experimental results. It is very difficult or impossible for most transient measurements to be experimented repeatedly under the same condition, so their uncertainty analysis differs from the method of analyzing static measurement data. The paper gives several main components of uncertainty and their experimental data of the measurement system of air shock wave pressure, especially analyses and processes dynamic sensitivity and overshoot values of the system excited by step pressure signal which is generated by shock tube. The results of uncertainty analysis are presented. The method of dynamic uncertainty provides a kind of solution to analyze and assess the result of single measurement or a few measurements.

Dusan Agrez
UNCERTAINTY OF NON-UNIFORM QUANTIZATION AND INFORMATION

In many analog-to-digital conversion schemes, numerical values are attained with successive approximations of the difference between the reference and measured quantity. For effectiveness of differential tracking, the non-uniform quantization must fulfil three conditions: partitions into halves, increasing quantization uncertainty with difference, and low overlapping of the quantization intervals. The best trade between the number of decision levels and the settling time is with pure exponential quantization rule. The fastest response is achievable with base 2. The information rate per step is a little below three. The number of bits decreases towards the end of conversion and the sharp stop of the uniform constant information flow is smoothed.

Edi Kulderknup
UNCERTAINTY OF OCCUPATIONAL HEALTH MEASUREMENTS

Occupational health measurements have considerable importance to safeguard the health of personnel in the working environment. Assurance of healthy conditions is prescribed in legal acts and if those requirements are not fulfilled can entrepreneur have considerable economical losses trough the authorities sanctions and charges for the damaged personnel. To have correct conformity estimation against legal limit values evaluator must have the reliable result of measurement and the truthful uncertainty estimation. Uncertainty estimation of occupational health measurements have some special particularities. Sound way to assure the best measurement capability is the interlaboratory comparison.

Jean-Marc Linares, Jean-Michel Sprauel, Bernard Schlatterer
UNCERTAINTY OF REFERENCE FRAMES APPLIED TO COMPUTER AIDED ORTHOPEDIC SURGERY

In this paper, mathematical tools, like Monte Carlo simulations and direct propagation methods based on the GUM, are experienced to calculate the uncertainty of a datum reference in orthopedic surgery. In the last approach, the Jacobian matrices of the measurement process are determined either by analytical calculus or through numerical computations. The methods are applied to the determination of reference frames in total knee arthroplasty. The different approaches are employed to calculate the uncertainties and the results are compared.

Edi Kulderknup, Jürgen Riim, Tuuli Levandi
UNCERTAINTY OF ROAD TRAFFIC SAFETY MEASUREMENTS

Road traffic has important part for the every days life. Traffic accidents are related to the vehicles technical side and to the traffic surveillance from authorities and police. Environment is damaged mainly through vehicles exhaust gases, noise and vibration. This study work deals with road traffic safety measurements uncertainties. Damages can be minimised if uncertainties of the measurements are estimated and taken into account by above areas. In this work will be given models of uncertainty estimation for the vehicles technical conditions measurements, environment safety measurements and authorities surveillance measurements. Estimated and validated are concrete values of the uncertainties for various situations using measurement comparison data.

S. Knotek, J. Geršl, A. Paták
Uncertainty of SO2 measurements in dryers due to water droplet and water film condensation

The article presents the modeling of SO2 diffusion into water droplet and water film which arise in dryers by condensation or evaporation in dependence on physical and chemical conditions. The motivation of the modeling is the attempt to quantify the SO2 loses in drying during sampling of emissions. The basic processes of gaseous substances dissolution into liquid are discussed theoretically and quantitative results of computer computations are presented.

J. Dobiliene, E. Raudiene, R. P. Žilinskas
UNCERTAINTY OF SPECTROMETRIC ANALYSIS

The main purpose of this paper is to present the uncertainty of spectrometric analysis considering peculiarities of chemical measurements. Qualitative evaluation of chemical–physical transformation and impact on uncertainty in spectrometric analysis is presented. Spectrophotometric method is used to show experimentally the influence of analysis conditions on the measurement result.

Consolatina Liguori
UNCERTAINTY ON SIGNAL PARAMETER ESTIMATION IN FREQUENCY DOMAIN

In the paper the analytical evaluation of theuncertainty on signal parameter estimation in frequency domain is dealt with. Two different and widely diffused algorithms able to compensate the spectral leakage effects due to asynchronous sampling are considered. The combined uncertainties on the final results (tones frequency, amplitude, and phase) due to the propagation of the uncertainty on the input samples are analytically evaluated. Simulation tests are then carried out in order to validate the obtained formulas.

Page 789 of 822 Results 7881 - 7890 of 8218