The results of examining error evaluation of the coverage factor with approximate methods in indirect measurements have been presented in the paper. Basing on the method?s accuracy analysis, the scope of application of the approximate methods of the expanded uncertainty estimation has been presented; the criterion of not-exceeding a preset value of the error has been implemented. The knowledge of coverage factor characteristics for the convolution of three selected probability distributions was used for the examination.
The paper deals with the measurement uncertainty evaluation of the A/D conversion based instruments, by using the effective number of bits (ENOB), which is a well know parameter, employed to characterize the overall behavior of an A/D converter. In order to verify if the ENOB can be also used to assess the measurement uncertainty, we use an ad hoc developed software tool. The results show that using the ENOB can lead to an underestimate of the uncertainties.
In this paper a procedure to determine the uncertainty of thickness measurement of thin layer is presented. The spectrophotometer method uses the spectrum of light transmission and some dependences between interference extremes and thickness of thin layer. The final result has been achieved by using a method recommended by Guide to the Expression of Uncertainty in Measurement. The standard uncertainty has been estimated by approach, called type B, which is based on manufacturer?s specification of spectrophotometer, experience in reading of results on transmission spectrum and literature data.
The problems associated with evaluation of uncertainty of volume and surface resistivities were presented in the paper. Special attention was paid to the measurements carried out on extremely high resistivity materials. Different factors affecting the uncertainty were classified and estimated. A simplified method of uncertainty evaluation was proposed.
Arithmetical operations performed on measurement results treated as intervals cause that the influence both errors distribution shape and errors correlation to the width of the resultant interval must be considered. The paper describes the use of reductive interval arithmetic in such a situation. Coherence coefficients which generally describe interdependence between intervals are interpreted as parameters of the error value set. The composition rule for two kinds of coefficients – those dependent on the shapes of the error distributions and those dependent on correlation between errors – is...
Measured data of blood chemical analysis (BCA) have uncertainty of measurement results in themselves. Generally, this problem is treated by statistical analysis and an effort to find effective factor for the quality control (QC) is studied. Generally, WHO rule is applied in the medical field. But in the rule, the uncertainty is controlled only by SD, CV and etc on the supposition, that the distribution of data is normal one. This is parametric analysis method in the statistical analysis of uncertainty data. On the other hand, recently application of ISO–GUM are discussed and practiced in...
The algorithms based on digital signal processing for impedance components’ evaluation in circuits with sampling transducer have been analysed. It is supposed that the voltage and current are sampled synchronously to the fundamental frequency of the generated sinusoidal signal. Two fitting sine wave algorithms, which are based on the least mean square (LMS) technique, have been described. The first one reconstructs indirect measurement method. The second algorithm estimates the unknown impedance components by direct method. The uncertainty’s propagation by described algorithms can be...
In 1948 Shannon founded the information theory. Originally developed for application in communication now it is used in various fields of science, so also in measurement and instrumentation. The paper represents as well a survey with important examples and results as new investigations in optimal systems. Last not least unsolved problems as the consideration of semantic aspects were treated.
Establishing the notion of equivalence, or indiscernibility, with the concept of attribute, precedes every measurement practice. The present paper proposes a formal theory of classification, and sheds a new light upon the notion of equivalence underlying nominal level of measurement. Assuming that each object is characterized by a set of predicates as a binary vector, whose components are 1 or 0 according as the object affirms a predicate or not, we first examine the relationship among objects in reference to the choice of predicates, or classifier, and formulate a formal theory of...
Basing upon the philosophical assumption that it is not possible to develop theory of measurement independent from the physical nature of measured objects, we formulate the topological theory of measurement. The model of measurement is a fibre bundle space with the base space D representing topological properties of measured quantity and fibres corresponding to the algebraic properties of space values of measured quantity. This model is consistent with the field theory.