Instrumentation and measurement methods

The latest publications in this offer are:

• April 10, 2026

  R291

  Bayesian approach of measurement uncertainty evaluation

  Measurement uncertainty evaluation is essential to scientific and industrial activities, and to trade, where it enables, among other things, the comparison of measurement results with each other or with a specification. The "Guide to the Evaluation and Expression of Uncertainty" (GUM) aims to propose harmonized practices for this evaluation.This article presents the Bayesian approach and the main Bayesian techniques used in metrology. It illustrates how this statistical framework makes it possible to address more complex situations, such as the estimation of calibration curves with uncertainties on both axes, or the use of prior information on the measurand, thereby opening up new perspectives.

• January 12, 2025

  IN212 Reviewed

  Development of chemical field-effect transistors for enzymatic detection

  Over the last few decades, we have witnessed a trend in many scientific fields towards greater operational and decision-making reliability. This trend is linked, on the one hand, to the explosion in computer systems and, on the other, to the increasing complexity and miniaturization of electronic systems. In the context of analysis, electronics technologies have naturally come up against multidisciplinary challenges involving physics, chemistry and/or biology. Microtechnologies were thus born, enabling the creation of "multi-physical/chemical" systems based on basic components from microelectronics, micromechanics and/or integrated optics.

• December 10, 2024

  R62

  Organisation of metrology in France. Cofrac – French Accreditation Body

  On the occasion of the 50th anniversary of the accreditation of calibration laboratories on July 1, 2023 and the 30th anniversary of Cofrac on April 29, 2024, this article specifies the role of Cofrac within the organization of metrology in France. Created in 1994, Cofrac's mission is to demonstrate, in France and internationally, that the organizations it accredits are competent and impartial. Decree No. 2008-1401 makes Cofrac the sole national accreditation body.Accreditation concerns conformity assessment bodies including laboratories, inspection bodies and certification bodies. To date, 300 calibration laboratories are accredited.

• April 10, 2024

  23

  Units of Measurements SI

  In the age of globalization, the international system of units, as we know it, seems obvious. This article presents its long and interesting history, as experienced by renowned scientists, its strict rules and exceptions.

• February 10, 2023

  R727

  Artificial intelligence evaluation

  Artificial intelligence (AI) is rapidly growing, questioning all audiences, individual, professional, academic. Rational and shared principles and practices to measure the performance and limits of intelligent systems have to be set up.A methodical approach that complies with the rules of metrology allows us to draw the broad outlines: metrics to carry out quantitative and repeatable performance measurements, physical and virtual testing environments to perform reproducible experiments that are representative of the real operating conditions of the AI being evaluated, and organizational tools (benchmarking, challenges, competitions) that meet the needs of the entire ecosystem.

• August 18, 2022

  R260 Reviewed

  Analysis of variance and regression. Design of experiments

  The engineer is often faced with a question of considerable practical importance: "Does this or that factor influence the measurement result? More precisely, such questions might be: "Does such-and-such an impurity affect the mechanical characteristics of such-and-such a material?" or: "Do all operators operating such-and-such a large piece of equipment in shift work actually achieve the same result, the same quality?" or: "Does such-and-such a parameter, which we have good physical reasons for believing to be important, actually influence the measurement results?". The preferred tool for this type of study is analysis of variance.

• August 18, 2022

  R250 Reviewed

  Estimators and hypothesis testing

  Very often, the information the engineer has to process concerns a random variable, for which he or she has no theoretical element enabling him or her to determine a priori – by reasoning alone – the mathematical expectation or standard deviation. From then on, he will have to rely on the notion of estimator, built from necessarily partial test results, and on the formulation of "hypotheses" that statistical analysis will lead him to reject or not. All the decisions he makes using these tools will be accompanied by a clearly quantified – consenti –risk.

• August 18, 2022

  R240 Reviewed

  Statistical observation

  This article follows on from Random Processes and random functions , to which the reader may refer for basic definitions. The examples that illustrate this article require consultation of tables and abacuses, which the reader will find in the article Statistical Tables..

• March 15, 2022

  R401 Reviewed

  Sensors - Design principles

  This article lists the design principles of sensors of physical or mechanical quantities. It solely presents the most commonly used devises such as, for instance sensors of torque, force , weight, pressure, proximity, displacement, temperature and gas. This list is thus not exhaustive. This article finishes by presenting the new generation of sensors and in particular the smart sensors which integrate an internal calculation devise, a signal conditioning system, a communication interface and chemical sensors.

• March 15, 2022

  R400 Reviewed

  Sensors - Definitions, detection principles

  The first element in the chain of measurements, the sensor is meant to emit an electrical signal proportional to the physical quantity to be measured. Where mechanical variables require a prior transformation in order to become an electrical quantity the sensor includes a primary element and a sensing element. This article presents the definitions and the terminology of metrology as well as the terms related to the functioning conditions of a sensor. It then details the detection principles used to design sensors: variation in resistance, capacity, frequency, luminous flux, etc.

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