Metrological Concepts Research Articles

Feasibility of Metrological Traceability Implementation Using the Joint Committee on Traceability in Laboratory Medicine Database Entries Including the Fulfillment of "Fit-for-Purpose" Maximum Allowable Measurement Uncertainty.

In previous publications, the Task Force on Reference Measurement System Implementation proposed a procedural approach combining a critical review of entries available in the Joint Committee on Traceability in Laboratory Medicine (JCTLM) database with a comparison of this information against analytical performance specifications for measurement uncertainty (MU) and applied it to a group of 13 measurands. Here we applied this approach to 17 additional measurands, of which measurements are frequently requested. The aims of the study were (a) to describe the main characteristics for implementing traceability and the potential to fulfill the maximum allowable MU (MAU) at the clinical sample level of certified reference materials and reference measurement procedures listed in the JCTLM database; (b) to discuss limitations and obstacles, if any, to the achievement of the required quality of laboratory measurements; and (c) to provide a gap analysis by highlighting what is still missing in the database. Results were integrated with those obtained in the previous study, therefore offering an overview of where we are and what is still missing in the practical application of the metrological traceability concept to 30 common biochemical tests employed in laboratory medicine. Our analysis shows that for 28 out of 30 measurands, conditions exist to correctly implement metrological traceability to the International System of units and fulfill at least the MAU of the minimum quality level derived according to internationally recommended models. For 2 measurands (serum albumin and chloride), further improvements in MU of higher-order references would be necessary.

An improved implementation of metrological traceability concepts is needed to benefit from standardization of laboratory results.

Non-harmonization of laboratory results represents a concrete risk for patient safety. To avoid harms, it is agreed that measurements by in vitro diagnostic medical devices (IVD-MD) on clinical samples should be traceable to higher-order references and adjusted to give the same result. However, metrological traceability is not a formal claim and has to be correctly implemented, which in practice does not happen for a non-negligible number of measurands. Stakeholders, such as higher-order reference providers, IVD manufacturers, and External Quality Assessment organizers, have major responsibilities and should improve their contribution by unambiguously and rigorously applying what is described in the International Organization for Standardization 17511:2020 standard and other documents provided by the international scientific bodies, such as Joint Committee on Traceability in Laboratory Medicine and IFCC. For their part, laboratory professionals should take responsibility to abandon non-selective methods and move to IVD-MDs displaying proper selectivity, which is one of the indispensable prerequisites for the correct implementation of metrological traceability. The practicality of metrological traceability concepts is not impossible but relevant education and appropriate training of all involved stakeholders are essential to obtain the expected benefits in terms of standardization.

METROLOGICAL CONCEPTS AND APPLICATIONS OF 3D OPTICAL SCANNING

METROLOGICAL CONCEPTS AND APPLICATIONS OF 3D OPTICAL SCANNING

Quality approach towards ISO/IEC 17025 accreditation at the center of analysis and characterization of Marrakesh Cadi Ayyad University: metrology stakes

In the context of the European Tempus project “Quality in Higher Agricultural Education in the Mediterranean (QESAMED)”, Analysis and Characterization Center of Cadi Ayyad University has committed to implement a quality approach according to the ISO/IEC 17025 standard. The first objective was to accredit the testing carried out in the microbiology laboratory in response to strong demand from the food industry in the Marrakesh region. The process began with an initial assessment of the center activities to identify the main gaps from ISO/IEC 17025. The range of laboratory and standard testing to be accredited were determined and an appropriate action plan was established. After that, a staff training was programmed to improve their skills in relation to this standard and metrology concepts. Implementation of the metrology function is one of the key steps for the deployment of the continuous improvement process. This function guarantees the traceability of measurements and the reliability of microbiological testing results. Several actions have been carried out, including: (i) identification of critical quantities and associated metrological requirements, (ii) checking of the metrological consistency of equipment through the calculation of the capability coefficient. The management of equipment requires several steps, from receipt of the equipment to its decommissioning or reform: (i) identification of the equipment, (ii) creation of equipment files, (iii) performance of calibration, verification, and maintenance operations. Ultimately, the definition of a strategy ensuring metrological traceability will optimize management costs by taking into account the structural constraints linked to the organization of metrology on a national scale.

Characterization of an OCT probe for use in the diagnosis of precancerous lesions of the cervix

The development of an auxiliary diagnostic tool (OCT probe) for application in the assessment of cervical cancer is being carried out and may have an impact on the diagnostic process and, consequently, on the reduction of the incidence of female mortality from cervical cancer, by allowing a more accurate assessment of the extent of the lesion and by enabling the expansion of this assessment within the endocervical canal. In addition to the scientific result, the use of available equipment will boost the quality of clinical care currently available for diagnosis. Combining technical development with a precise methodology and clinical application, the probe developed will have a scientific impact of socio-economic relevance for society. As it is an optical measurement, it is necessary to evaluate the optical characteristics of the developed probes and the choice of one of them was made taking into account the measurements carried out and the application of metrological concepts.

Metrology in the early days of Social Sciences

Recent studies have been endeavoring to overcome challenges to ensure reliable measurement results in Social Sciences and Humanities facing the complex characteristics of this scientific field. However, the literature indicates that the founding designers of sociology as an academic discipline expressed concerns regarding social measurements more than a century ago. Based on a literature review, the present work investigates possible metrological aspects already addressed in the early days of Social Science, focusing on the methodological conceptions of two of sociology’s early canons – notably Max Weber and Emile Durkheim. The present study reveals that the approaches contemporaneously developed by the two Social Sciences co-founders present diverse but fundamentally complementary configurations, allowing a wide range of social phenomena to be analyzable. Although employing their terminologies, both social scientists incorporated fundamental metrological concepts in their procedures’ parameters, seeking to establish a single reference, using statistical analysis or determining measurement standards that resemble what is known today as reference material. The concern with applying metrological concepts since the early days of creating sociology as a science reinforces the need to invest extensive efforts to provide uniformity of measurements in this remarkably relevant field of application of Measurement Science.

Metrology for data in life sciences, healthcare and pharmaceutical manufacturing: Case studies from the National Physical Laboratory

Data metrology, i.e., the evaluation of data quality and its fitness-for-purpose, is an inherent part of many disciplines including physics and engineering. In other domains such as life sciences, medicine, and pharmaceutical manufacturing these tools are often added as an afterthought, if considered at all. The use of data-driven decision making and the advent of machine learning in these industries has created an urgent demand for harmonised, high-quality, content rich, and instantly available datasets across domains. The Findable, Accessible, Interoperable, Reproducible principles are designed to improve overall quality of research data. However, these principles alone do not guarantee that data is fit-for-purpose. Issues such as missing data and metadata, insufficient knowledge of measurement conditions or data provenance are well known and can be aided by applying metrological concepts to data preparation to increase confidence. This work conducted by National Physical Laboratory Data Science team showcases life sciences and healthcare projects where data metrology has been used to improve data quality.

Using Ontologies to Create Machine-Actionable Datasets: Two Case Studies

Achieving the highest levels of compliance with the FAIR (findable, accessible, interoperable, reusable) principles for scientific data management and stewardship requires machine-actionable semantic representations of data and metadata. Human and machine interpretation and reuse of measurement datasets rely on metrological information that is often specified inconsistently or cannot be inferred automatically, while several ontologies to capture the metrological information are available, practical implementation examples are few. This work aims to close this gap by discussing how standardised measurement data and metadata could be presented using semantic web technologies. The examples provided in this paper are machine-actionable descriptions of Earth observation and bathymetry measurement datasets, based on two ontologies of quantities and units of measurement selected for their prominence in the semantic web. The selected ontologies demonstrated a good coverage of the concepts related to quantities, dimensions, and individual units as well as systems of units, but showed variations and gaps in the coverage, completeness and traceability of other metrology concept representations such as standard uncertainty, expanded uncertainty, combined uncertainty, coverage factor, probability distribution, etc. These results highlight the need for both (I) user-friendly tools for semantic representations of measurement datasets and (II) the establishment of good practices within each scientific community. Further work will consequently investigate how to support ontology modelling for measurement uncertainty and associated concepts.

Measurement uncertainty.

Over time, the metrological concept of uncertainty in measurement has been very successfully integrated into laboratory sciences. For proper implementation, an understanding of specific metrology terminology and additional concepts such as metrology traceability and commutability is necessary. Although the original thinking about measurement uncertainty in laboratory medicine suggests the complexity of the concept, it basically refers to the result as the end product of the entire laboratory process. Although the data on measurement uncertainty can be expressed quantitatively, the basis of this concept is the continuous evaluation of all phases of the laboratory process. This means that laboratory experts should keep in mind that the extra-analytical phases (on which the uncertainty of the measurement results may depend the most) must be continuously monitored. The analytical phase can be "held in check" by established internal and external quality control processes. It is the internal/external quality control data that is used to calculate the numerical value of the measurement uncertainty of the measurement results. Although over time the awareness of laboratory experts regarding the concept of measurement uncertainty has increased, there are still many challenges that need to be followed, and the last one is how to achieve a balance between understanding, evaluation process and application of measurement uncertainty data of measurement results for complete and ultimate practical use.

Perception for Autonomous Systems: A Measurement Perspective on Localization and Positioning

Autonomous systems are nowadays having an undisputed pervasiveness in modern society. Autonomous driving cars as well as applications of service robots (e.g., cleaning robots, companion robots, intelligent healthcare solutions, tour guided systems) are becoming more and more popular, and a general acceptance is now developing around such systems. Nonetheless, one of the major hurdles in building such applications relies on the capability of autonomous systems to understand their surroundings and then plan proper actions. The most popular solutions, which are gaining more and more attention, rely on artificial intelligence and deep learning as a means to perceive the structured and complex natural environment. Nonetheless, classical concepts of metrology, such as standard uncertainty, accuracy and precision, are still necessary for a clear and effective understanding of modern autonomous systems applications. In this paper, some fundamental measurement concepts will be reviewed in light of the autonomous systems domain, with an emphasis on localization and positioning problems for mobile robots. In particular, we will discuss and present the main issues and concepts that build around the statistical approach to measurements and the main role of uncertainties.

Quantum enhanced metrology in the search for fundamental physical phenomena

These notes summarize lectures given at the 2019 Les Houches summer school on Quantum Information Machines. They describe and review an application of quantum metrology concepts to searches for ultralight dark matter. In particular, for ultralight dark matter that couples as a weak classical force to a laboratory harmonic oscillator, quantum squeezing benefits experiments in which the mass of the dark matter particle is unknown. This benefit is present even if the oscillatory dark matter signal is much more coherent than the harmonic oscillator that it couples to, as is the case for microwave frequency searches for dark matter axion particles.

Metrological and quality concepts in analytical chemistry (IUPAC Recommendations 2021)

Metrological and quality concepts in analytical chemistry (IUPAC Recommendations 2021)

Application of systems thinking to the establishment of metrological traceability chains

International agreements in the field of metrology and accreditation of calibration laboratories are the basis for establishing global metrological traceability. Important elements of metrological traceability are calibration of measurement standards and measuring instruments, assessment of measurement uncertainty. The International Laboratory Accreditation Cooperation has a specific policy regarding on traceability of measurement results and estimation of measurement uncertainty in calibration.
 The partial concept diagram around metrological traceability in accordance with the International Vocabulary of Metrology is proposed. This diagram contains a total of nine metrological concepts, which have most of the associative relations. There are associative relations between the concept of metrological traceability chain and concepts of metrological traceability, measurement standard, calibration and calibration hierarchy, and through the concept of measurement standard with the concept of measurement uncertainty.
 Systems thinking to the analysis of state of proposed terminological system around metrological traceability was applied. For construction of generalized metrological traceability chain, all the established properties of the system elements around the terminology system of metrological traceability were taken into account.
 Generalized metrological traceability chain for different levels of the calibration hierarchy was proposed. The proposed chain can be used to develop appropriate chains for specific areas of measurement. To achieve this, it is necessary to determine the specific measured value, the required measurement uncertainty for different levels of the calibration hierarchy and select the necessary measurement standards. Such schemes should be used in national metrology institutes and calibration laboratories.

Phenomenological physical foundations of structural dynamics in technical mechanics

The article deals with the problem of forming dynamic thinking in the course of technical mechanics. This problem covers various forms and levels of professional training, including engineering courses in structural mechanics, postgraduate and doctoral studies. The study of this problem in the article is carried out using dynamic concepts in technical physics and metrology. The main method for analyzing this problem is the method and theory of vibroacoustic computational modeling developed by Prof. Hlystunov M.S. The article presents a comparative analysis of the reaction of a cantilever beam to static and dynamic load. The dynamic characteristics of such a beam, including its AFFC, AFC and FFC, resonances and antiresonances, are considered. Then we consider the reaction of the simplest two-rod frame to a dynamic load and its fundamental difference from the reaction to a static load. The article provides detailed mathematical calculations using the corresponding section of operational calculus. The terms, definitions, and mathematical representations used in the article correspond to similar classical concepts that are widely used in metrology, technical cybernetics, and technical physics. The article is provided with the necessary illustrations for a visual representation of the main dynamic characteristics and properties of building structures.

Nominal Constructions of the Vertical Level in the Yakut Language

At present, the grammatical and semantic study of nominal constructions as a means of conveying metrological concepts is believed to reveal the general picture of the study of the functional grammar of the Yakut (Saha) language. Widespread constructions obtained by the method of continuous sampling from Yakut imaginative literature and folklore serve as the material of the research. The purpose of the article is to identify the structural and semantic features of the expression of nominal structures on the material of the Yakut language. As the subject matter of the research, we chose constructions of a nominal type, expressing the height / growth of an object, the depth of substances, and the length of hanging objects.It is postulated that in the Yakut language, typical constructions with the instrumental affix -nan and with the dative affix-ar,-garin combination with the postpositionsdieri,dylyandtiyeʻdo, up to’as means of expressing the level differ from each other not only in their structure, but also semantically. To identify the grammatical and semantic features of nominal constructions with the meaning of the level, different techniques have been used: morphoglossing, taking into account the linguistic specificity of the language, based on the Leipzig rules for the representation of texts, metalanguage transmission of the meaning of the level, description of semantic groups and subgroups, semantic analysis of the nominal structure.The basic nominal and postpositional constructions with the meaning of the level are presented; the component composition of the studied units is described; considered and described is also the semantic structure of qualitative-adverbial units with quantitative meaning. Based on the material of the studied units, it has been established that the situation of measuring the vertical level has its own cognitive significance, which is mostly associated with anthropocentrism. The main names of body parts with the instrumental affix-nan, capable of acting as level indicators, except forharahʻeyesʼ,haasʻebrowsʼ,uosʻlip(s)ʼ,tisʻtooth(s)ʼ, and other parts of a person’s face are revealed. Constructions with the instrumental case preposition -nan are more static and are mainly used with the verbs of being; the constructions with the dative affix-garand the postpositionsdyly,dieri,tiyeʻdo, up toʼ show more dynamics, thanks to the verbs of movement and achievement.

Aberration calibration and correction with nano-scatterers in digital holographic microscopy for semiconductor metrology.

Overlay metrology measures pattern placement between two layers in a semiconductor chip. The continuous shrinking of device dimensions drives the need to explore novel optical overlay metrology concepts that can address many of the existing metrology challenges. We present a compact dark-field digital holographic microscope that uses only a single imaging lens. Our microscope offers several features that are beneficial for overlay metrology, like a large wavelength range. However, imaging with a single lens results in highly aberrated images. In this work, we present an aberration calibration and correction method using nano-sized point scatterers on a silicon substrate. Computational imaging techniques are used to recover the full wavefront error, and we use this to correct for the lens aberrations. We present measured data to verify the calibration method and we discuss potential calibration error sources that must be considered. A comparison with a ZEMAX calculation is also presented to evaluate the performance of the presented method.

Analysis of measurement uncertainty sources in the casting process

The concepts used in metrology are increasingly part of the productive process of metallurgical companies, considering the globalization of the world market. The interpretation of metrological concepts and their application in decision-making is still a challenge for the industry, especially for the measurement uncertainty calculation. Industries in the casting area are in great need of skilled labor both in relation to the productive process and engineering, as well as in metrology, highlighting the interdisciplinary of the concepts studied in the technical or baccalaureate courses. Therefore, the main objective of this work is to perform a brief literature review of publications made using the value of uncertainty of measurement within the production process of foundries. The results show that there is a potential research in the field, to which it relates the values of measurement uncertainty and fused components.

Study of the relationship between acupuncture dose and effect

Study of the relationship between acupuncture dose and effect

Metrological and quality concepts in analytical chemistry (IUPAC Recommendations 2021)

Abstract Recommendations are given for metrological terminology in analytical chemistry. Analytical chemistry is defined, and concepts related to laboratory practice are termed and defined. Recommendations are given concerning the terminology of quality assurance in analytical chemistry. Terms draw on the extensive quality literature, particularly from ISO.

26.3: Advanced Alignment and Metrology Concepts Using Photometric Robotics with Examples for Automotive Displays

The alignment quality and reproducibility in ILMD (Imaging Luminance Measurement Device) based display metrology has a great influence on the reproducibility of the obtained measurement data. In this context, this contribution outlines and introduces several advanced measurement and alignment concepts that can be performed with “photometric robotics.” The term describes machine vision performed with an ILMD supported by robotic movements.