416 research outputs found
Evolution of the concept of measurement uncertainty - From errors to probability density functions
No full textThis paper is based on “From errors to probability density
functions - Evolution of the concept of measurement uncertainty”
by Walter Bich, which will be published in a forthcoming issue of
IEEE Transactions on Instrumentation and Measurement.
© 2012 IEE
The third-millennium International System of Units
No full textThe International System of Units, SI, in use since 1946, was formally established in October 1960 by the eleventh Conférence Générale des Poids et Mesures, CGPM, with its resolution 12. In the past years, several changes have been made to the system. The 26th Conference, on 16th November 2018, adopted a revised SI, due to come into force on 20 May 2019. This revision was by far the most radical in the history of the SI. In this paper, I review the system from its origin to the present time, discuss the needs that suggested, and the conditions that allowed such an epochal change, and present the SI of the third millennium
Existence of pseudo-equilibria in a financial economy
No full textThis paper proves the existence of a pseudo-equilibrium in a financial economy with incomplete markets in which the agents may have nonordered preferences. We will use a fixed-point-like theorem of Bich and Cornet that generalizes the results by Hirsch, Magill, Mas-Colell [18] and Husseini, Lasry, Magill [19] to encompass the framework considered by Gale and Mas-Colell ([14], [15]).Pseudo-equilibrium ; incomplete markets ; nonordered preferences ; fixed-point-like theorems ; Grassmann manifold
Interactions entre pairs lors de la révision collaborative étayée
No full textIl s'agit d'un corpus de dix interactions verbales en vietnamien et en français produites par trois groupes de pairs lors de leurs séances de révision collaborative étayée.DO, Thi Bich Thuy (2011). Les impacts de la révision collaborative étayée : une recherche-action en didactique de la production écrite en FLE. Thèse de doctorat en Sciences du Langage : Université Aix-Marseille 1
Revision of the ‘Guide to the Expression of Uncertainty in Measurement’. Why and how
No full textThe ``Guide to the expression of uncertainty in measurement'' has now served for more than twenty years. In this communication, after attempting a balance over this period, the logical reasons are given that, on the one hand, led to the decision to update such a successful document, and, on the other hand, dictated the modifications that are being carried out with respect to the current 2008 edition.
The author is convener of the Joint Committee for Guides in Metrology (JCGM) Working Group 1 (Guide to the expression of uncertainty in measurement, or GUM). The opinion expressed in this paper does not necessarily represent the view of this Working Group
From Errors to Probability Density Functions. Evolution of the Concept of Measurement Uncertainty
No full textThe concept of uncertainty in measurement stems from that of (probable) error and is intimately intertwined with it. Both concepts can be viewed as measures of the quality of a measurement or, better, of the corresponding estimate. There is an endless list of misunderstandings, false beliefs, and misinterpretations on this subject. People tend also to use the same word with different meanings. In this paper, while giving an overview of the evolution of the concept, from the initial unawareness of the need for a quality assessment (still present in many areas) to the present views, the author also tries to shed some light and some clarity on the most popular and debated misunderstandings, particularly about the concepts of error, true quantity value(s), and measured quantity value. The author is the convener of the Joint Committee for Guides in Metrology Working Group 1 (Guide to the expression of uncertainty in measurement). The opinion expressed in this paper does not necessarily represent the view of this working group
Error, uncertainty and probability
No full textThere is much confusion on the topic of uncertainty of measurement. Yet, measurement uncertainty is both a pivotal concept in measurement theory and, above all, a basic requisite in practice, from the physics laboratory measuring some exotic property of Nature to the shop floor. The purpose of this paper is to give the author's view on measurement uncertainty in an unambiguous way, thus privileging clarity over diplomacy, for which he apologizes once and for all. Accordingly, the scope of the paper is to discuss the fundamental metrological concepts and associated terms, as given in the International Vocabulary of Metrology, VIM, in the light of their relevance to the topic of uncertainty, as treated in the Guide to the expression of uncertainty in measurement, GUM. In this scheme, the focus is on the concepts of error and uncertainty and on their intimate connection, often masked by misunderstanding when not buried under the misconception that they are opposite and competing concepts. It will be shown that probability theory is the correct framework in which error and uncertainty are reconciled in a convenient and rigorous way.
The author is convener of the Joint Committee for Guides in Metrology (JCGM) Working Group 1 (GUM). The opinion expressed in this paper does not necessarily represent the view of this Working Group
Existence of pseudo-equilibria in a financial economy
No full textThis paper proves the existence of a pseudo-equilibrium in a financial economy with incomplete markets in which the agents may have nonordered preferences. We will use a fixed-point-like theorem of [4] that generalizes the results by Hirsch, Magill, Mas-Colell [18] and Husseini, Lasry, Magill [19] to encompass the framework considered by Gale and Mas-Colell ([14],[15]).Pseudo-equilibrium, incomplete markets, nonordered preferences, fixed-point-like theorems, Grassmann manifold.
Evaluating Measurement Uncertainty in Absolute Gravimetry: an Application of the Monte Carlo Method
No full textAbsolute gravity measurements are based on the reconstruction of the free-falling motion of a test body in vacuum. In this paper, two large disturbing effects are studied, namely, the non- gravitational accelerations originated by rotation and translation of the flying body. Their contribution to the uncertainty of the free-fall acceleration is evaluated using the method proposed in Supplement 1 to the GUM. The analysis is specifically applied to the IMGC-02 absolute gravimeter, but can be easily extended to other instruments
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