Pub Date : 1900-01-01DOI: 10.51843/wsproceedings.2018.19
N. Vlajic
The ability to measure rapidly time-varying quantities is a continued and growing interest in the metrological community, which has been driven, in part, by the need to accurately measure dynamic mechanical quantities (e.g., pressure, force, acceleration). Within the mechanical domain, force indicating instruments are different from most other types of sensors, as the force sensor must also transmit the quantity being measured. Consequently, the force measurement instrument becomes part of the engineering structure or measurement system. While this integration of sensor-system typically does not pose many design or metrological challenges for static or stationary forces, the implications for dynamic measurements are often profound. For example, high-performance force transducers can be statically calibrated with less than 10 parts-per-million uncertainty (k=1); however, the dynamic sensitivity has been shown to deviate by several orders of magnitude from the static sensitivity for certain rates of dynamic forces. We describe some of the physical challenges in making accurate dynamic force measurements, as well as commonly used dynamic force calibration techniques. The introductory dynamic force concepts covered here serve as a foundation for designing engineering systems with the intent of measuring time-varying forces.
{"title":"An Introduction to Dynamic Force Metrology","authors":"N. Vlajic","doi":"10.51843/wsproceedings.2018.19","DOIUrl":"https://doi.org/10.51843/wsproceedings.2018.19","url":null,"abstract":"The ability to measure rapidly time-varying quantities is a continued and growing interest in the metrological community, which has been driven, in part, by the need to accurately measure dynamic mechanical quantities (e.g., pressure, force, acceleration). Within the mechanical domain, force indicating instruments are different from most other types of sensors, as the force sensor must also transmit the quantity being measured. Consequently, the force measurement instrument becomes part of the engineering structure or measurement system. While this integration of sensor-system typically does not pose many design or metrological challenges for static or stationary forces, the implications for dynamic measurements are often profound. For example, high-performance force transducers can be statically calibrated with less than 10 parts-per-million uncertainty (k=1); however, the dynamic sensitivity has been shown to deviate by several orders of magnitude from the static sensitivity for certain rates of dynamic forces. We describe some of the physical challenges in making accurate dynamic force measurements, as well as commonly used dynamic force calibration techniques. The introductory dynamic force concepts covered here serve as a foundation for designing engineering systems with the intent of measuring time-varying forces.","PeriodicalId":120844,"journal":{"name":"NCSL International Workshop & Symposium Conference Proceedings 2018","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125766425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.51843/wsproceedings.2018.26
T. Kolat
Thermocouples are rugged, fast responding temperature sensors that very often cover large ranges of temperature. In addition, their economical affordability and ease of adaptation to a variety of configurations serve to increase their popularity and consequently the customer demand for traceable calibrations. Like all other measurement and test equipment, thermocouples, due primarily to their classification categories, exhibit a range of performances and accuracy expectations. This establishes the need for several methods of testing and analysis for effective, accurate result reporting with respect to the written standard and the temperature scale. This paper and its presentation discuss approaches employed to calibrate thermocouples and report their calibration results. It continues by illustrating some of the mathematics that can be used to furnish results on the calibration certificate. Examples of those applications with realistic thermocouple data are shown.
{"title":"Thermocouple Testing Methods, Data Analysis and Reporting Calibration Results with Emphasis on Noble Metal Types","authors":"T. Kolat","doi":"10.51843/wsproceedings.2018.26","DOIUrl":"https://doi.org/10.51843/wsproceedings.2018.26","url":null,"abstract":"Thermocouples are rugged, fast responding temperature sensors that very often cover large ranges of temperature. In addition, their economical affordability and ease of adaptation to a variety of configurations serve to increase their popularity and consequently the customer demand for traceable calibrations. Like all other measurement and test equipment, thermocouples, due primarily to their classification categories, exhibit a range of performances and accuracy expectations. This establishes the need for several methods of testing and analysis for effective, accurate result reporting with respect to the written standard and the temperature scale. This paper and its presentation discuss approaches employed to calibrate thermocouples and report their calibration results. It continues by illustrating some of the mathematics that can be used to furnish results on the calibration certificate. Examples of those applications with realistic thermocouple data are shown.","PeriodicalId":120844,"journal":{"name":"NCSL International Workshop & Symposium Conference Proceedings 2018","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128099747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.51843/wsproceedings.2018.42
Jenniffer Romero Parrado
In the Temperature and Humidity Laboratory of the Colombian National Metrology Institute (INM, for the Spanish acronym), the ISOTECH model ITL-M-17702 high temperature furnace is used to the realization of the freezing point of aluminum (660.323 °C). The furnace has a master controller which uses a PID control function to adjust the operating temperature, in agreement with the parameters set out in the laboratory’s measurement procedures. As part of the development of a knowledge-building innovation project at the INM, an automation software was designed for the remote configuration of the furnace and modular data acquisition for each of the furnace’s operational stages (heating, stabilization). LabView® platform were used to implement communications protocols for the controller and to design a master-slave programming structure. This project allows for the user to configure work parameters that include operational temperature and measurement time, with the purpose of having all data generated throughout the process recorded and stored in a reliable manner for its subsequent metrological analysis, additionally promoting the maintenance of the integrity of the furnace by avoiding the configuration errors associated with direct handling. This project is the first phase in implementing a new calibration service related to the quantity of temperature, geared towards meeting the scientific and industrial metrological needs of the country.
{"title":"Metrological Parameterization of a High Temperature Furnace Using LabView® at INM Colombia","authors":"Jenniffer Romero Parrado","doi":"10.51843/wsproceedings.2018.42","DOIUrl":"https://doi.org/10.51843/wsproceedings.2018.42","url":null,"abstract":"In the Temperature and Humidity Laboratory of the Colombian National Metrology Institute (INM, for the Spanish acronym), the ISOTECH model ITL-M-17702 high temperature furnace is used to the realization of the freezing point of aluminum (660.323 °C). The furnace has a master controller which uses a PID control function to adjust the operating temperature, in agreement with the parameters set out in the laboratory’s measurement procedures. As part of the development of a knowledge-building innovation project at the INM, an automation software was designed for the remote configuration of the furnace and modular data acquisition for each of the furnace’s operational stages (heating, stabilization). LabView® platform were used to implement communications protocols for the controller and to design a master-slave programming structure. This project allows for the user to configure work parameters that include operational temperature and measurement time, with the purpose of having all data generated throughout the process recorded and stored in a reliable manner for its subsequent metrological analysis, additionally promoting the maintenance of the integrity of the furnace by avoiding the configuration errors associated with direct handling. This project is the first phase in implementing a new calibration service related to the quantity of temperature, geared towards meeting the scientific and industrial metrological needs of the country.","PeriodicalId":120844,"journal":{"name":"NCSL International Workshop & Symposium Conference Proceedings 2018","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132622955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.51843/wsproceedings.2018.02
Michael Dobbert
On October 8th, 2017, multiple catastrophic wildfires broke out in Northern California, resulting in loss of life and $3.3 billion in damage. The fire displaced a significant portion of the community due to evacuations and destroyed homes. Keysight Technologies corporate headquarters and the homes of many employees, were located inside the burn perimeter of the Tubbs fire. After the fire, the site was inaccessible for several days, with only limited access thereafter. Several of the main Keysight buildings experienced smoke and water damage. These buildings house corporate activities, R&D, marketing and manufacturing operations, a standards laboratory and a testing laboratory. The primary impact from the smoke was a light coating of soot and a smoky odor inside the buildings, which required extensive cleaning. Water damage was minimal. While the condition of calibration standards and electronic testing equipment was initially unknown, testing revealed negligible impact from the smoke and soot. This paper discusses the processes for re-establishing calibration status and traceability, the challenges in bringing revenue generating operations back on-line and the value of business recovery planning.
{"title":"Disaster Recovery: Managing the Recovery From the 2017 Northern California Wildfires","authors":"Michael Dobbert","doi":"10.51843/wsproceedings.2018.02","DOIUrl":"https://doi.org/10.51843/wsproceedings.2018.02","url":null,"abstract":"On October 8th, 2017, multiple catastrophic wildfires broke out in Northern California, resulting in loss of life and $3.3 billion in damage. The fire displaced a significant portion of the community due to evacuations and destroyed homes. Keysight Technologies corporate headquarters and the homes of many employees, were located inside the burn perimeter of the Tubbs fire. After the fire, the site was inaccessible for several days, with only limited access thereafter. Several of the main Keysight buildings experienced smoke and water damage. These buildings house corporate activities, R&D, marketing and manufacturing operations, a standards laboratory and a testing laboratory. The primary impact from the smoke was a light coating of soot and a smoky odor inside the buildings, which required extensive cleaning. Water damage was minimal. While the condition of calibration standards and electronic testing equipment was initially unknown, testing revealed negligible impact from the smoke and soot. This paper discusses the processes for re-establishing calibration status and traceability, the challenges in bringing revenue generating operations back on-line and the value of business recovery planning.","PeriodicalId":120844,"journal":{"name":"NCSL International Workshop & Symposium Conference Proceedings 2018","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131107351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.51843/wsproceedings.2018.22
M. Kuster
What if your organization’s measurement, analysis and management computing systems spoke a shared language with other world-wide measurement-related systems? How would that affect your business? How would it ease your ISO/IEC 17025 compliance challenges? Imagine a set of normative standards that define data structures, taxonomies, service protocols and security for locating, communicating and sharing measurement information. Those standards comprise what we call a measurement information infrastructure, or MII. In 2017, the NCSLI MII & Automation Committee presented the MII Vision and held discussion on its progress. This year’s open discussion panel session focuses on the taxonomies required to implement an MII and highlight how you may participate in the real-world benefits it will create and the efforts underway to realize them. The session will also demonstrate some MII-aware software under development.
{"title":"Taxonomies for a Metrology Information Infrastructure","authors":"M. Kuster","doi":"10.51843/wsproceedings.2018.22","DOIUrl":"https://doi.org/10.51843/wsproceedings.2018.22","url":null,"abstract":"What if your organization’s measurement, analysis and management computing systems spoke a shared language with other world-wide measurement-related systems? How would that affect your business? How would it ease your ISO/IEC 17025 compliance challenges? Imagine a set of normative standards that define data structures, taxonomies, service protocols and security for locating, communicating and sharing measurement information. Those standards comprise what we call a measurement information infrastructure, or MII. In 2017, the NCSLI MII & Automation Committee presented the MII Vision and held discussion on its progress. This year’s open discussion panel session focuses on the taxonomies required to implement an MII and highlight how you may participate in the real-world benefits it will create and the efforts underway to realize them. The session will also demonstrate some MII-aware software under development.","PeriodicalId":120844,"journal":{"name":"NCSL International Workshop & Symposium Conference Proceedings 2018","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115766703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.51843/wsproceedings.2018.03
Dr. Nobu-Hisa Kaneko
To validate a calibration capability of calibration laboratories, it is necessary to carry out an appropriate inter laboratory comparison. However, as is often the case with some extreme ranges of the measurements, e. g., extremely high resistance, it is difficult to arrange such a comparison. In this study, in the collaboration work between the National Metrology Institute of Japan (NMIJ/AIST) and calibration laboratories, an inter-laboratory comparison for extremely high resistance standards as high as 100 TΩ has been established. The demonstration of validation of calibration capability has been performed from 1 MΩ to 100 GΩ with a set of stable high-resistance standard resistors circulating among three participants. The NMIJ/AIST provided the reference value for this comparison, and each of the three participants calibrated the circulated set of artifacts employing their system built to be traceable to the national standard. Although the equipment and traceability scheme differed among the participants, the results agreed well and the En values of each laboratory were below 1. At the conference, the protocol and final report of this comparison will be presented.
{"title":"Inter Laboratory Comparison of High Resistance Standard in Japan","authors":"Dr. Nobu-Hisa Kaneko","doi":"10.51843/wsproceedings.2018.03","DOIUrl":"https://doi.org/10.51843/wsproceedings.2018.03","url":null,"abstract":"To validate a calibration capability of calibration laboratories, it is necessary to carry out an appropriate inter laboratory comparison. However, as is often the case with some extreme ranges of the measurements, e. g., extremely high resistance, it is difficult to arrange such a comparison. In this study, in the collaboration work between the National Metrology Institute of Japan (NMIJ/AIST) and calibration laboratories, an inter-laboratory comparison for extremely high resistance standards as high as 100 TΩ has been established. The demonstration of validation of calibration capability has been performed from 1 MΩ to 100 GΩ with a set of stable high-resistance standard resistors circulating among three participants. The NMIJ/AIST provided the reference value for this comparison, and each of the three participants calibrated the circulated set of artifacts employing their system built to be traceable to the national standard. Although the equipment and traceability scheme differed among the participants, the results agreed well and the En values of each laboratory were below 1. At the conference, the protocol and final report of this comparison will be presented.","PeriodicalId":120844,"journal":{"name":"NCSL International Workshop & Symposium Conference Proceedings 2018","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121265180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.51843/wsproceedings.2018.05
Kevin Abercrombie
Earned Value Management (EVM) is a Project Management tool for monitoring performance. EVM provides the Project and Program Managers with a tool for monitoring progress and predicting success. This paper examines the use of EVM to monitor laboratory performance both from a laboratory perspective and a customer perspective.
{"title":"Using Earned Value Management to Monitor Laboratory Performance","authors":"Kevin Abercrombie","doi":"10.51843/wsproceedings.2018.05","DOIUrl":"https://doi.org/10.51843/wsproceedings.2018.05","url":null,"abstract":"Earned Value Management (EVM) is a Project Management tool for monitoring performance. EVM provides the Project and Program Managers with a tool for monitoring progress and predicting success. This paper examines the use of EVM to monitor laboratory performance both from a laboratory perspective and a customer perspective.","PeriodicalId":120844,"journal":{"name":"NCSL International Workshop & Symposium Conference Proceedings 2018","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124063994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.51843/wsproceedings.2018.41
Tsung-Ping Lee
From year 2015, owing to National Space Organization (here shorted by NSPO) internal a great quantity of requirements for instruments calibration, automated and semi-automated calibration systems started to build up, writing by computer programs C# to control and retrieve data from varies instruments and modules, in brand of instruments for example: Agilent, FLUKE, HP ,Keithley, Keysight, National Instruments and Tektronix. In order to solve issues of automatically generating uncertainties and calibration reports, templates using Microsoft Word according to the characteristics of the instrument have been classified and created. It benefits in calibration efficiency and precision because data retrieving and calibration reports can be created only one button. At the same time, calibration records can be found including uncertainty and degree of freedom of each component, expanded uncertainty and effective degree of freedom. After 2 years calibration experience, NSPO started to apply accreditation of Taiwan Accreditation Foundation (TAF) and have been accredited from April 10, 2017 by TAF. In order to satisfy requirements of TAF, for example: calibration report’s format, the logic of computer program by C# have been modified and validated by TAF. Therefore, NSPO can issue a report with both TAF logo and ILAC-MRA logo after calibrated instruments for customers. Owing to customers trust, NSPO stated to service external customers from May of 2017. Nowadays, NSPO have set up systems including Power Supply, Multi-Functions Meters, NI-4431 module series, Multi-functions Signal Generator, Current Probes, Electric-Load and Thermo-couple Meters. Systems in building and planning are Oscilloscope (building), Signal Conditioner (docs building) and Ionizing-gage/meters (planning, for High-Vacuum chambers). The main purpose to join this workshop is to share benefits of automated and semi-automated calibration system and to understand requirements from end-users.
{"title":"More Efficient Solving Calibration Issues by Automated and Semi-Automated Calibration Systems","authors":"Tsung-Ping Lee","doi":"10.51843/wsproceedings.2018.41","DOIUrl":"https://doi.org/10.51843/wsproceedings.2018.41","url":null,"abstract":"From year 2015, owing to National Space Organization (here shorted by NSPO) internal a great quantity of requirements for instruments calibration, automated and semi-automated calibration systems started to build up, writing by computer programs C# to control and retrieve data from varies instruments and modules, in brand of instruments for example: Agilent, FLUKE, HP ,Keithley, Keysight, National Instruments and Tektronix. In order to solve issues of automatically generating uncertainties and calibration reports, templates using Microsoft Word according to the characteristics of the instrument have been classified and created. It benefits in calibration efficiency and precision because data retrieving and calibration reports can be created only one button. At the same time, calibration records can be found including uncertainty and degree of freedom of each component, expanded uncertainty and effective degree of freedom. After 2 years calibration experience, NSPO started to apply accreditation of Taiwan Accreditation Foundation (TAF) and have been accredited from April 10, 2017 by TAF. In order to satisfy requirements of TAF, for example: calibration report’s format, the logic of computer program by C# have been modified and validated by TAF. Therefore, NSPO can issue a report with both TAF logo and ILAC-MRA logo after calibrated instruments for customers. Owing to customers trust, NSPO stated to service external customers from May of 2017. Nowadays, NSPO have set up systems including Power Supply, Multi-Functions Meters, NI-4431 module series, Multi-functions Signal Generator, Current Probes, Electric-Load and Thermo-couple Meters. Systems in building and planning are Oscilloscope (building), Signal Conditioner (docs building) and Ionizing-gage/meters (planning, for High-Vacuum chambers). The main purpose to join this workshop is to share benefits of automated and semi-automated calibration system and to understand requirements from end-users.","PeriodicalId":120844,"journal":{"name":"NCSL International Workshop & Symposium Conference Proceedings 2018","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124758593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.51843/wsproceedings.2018.16
S. Dwyer
Metrology engineers want technically correct answers. Managers want to make decisions that trade off cost against product value. Calibration personnel want their work to count. Calibration intervals drive measurement reliability, the calibration budget, and the value of every calibration. We affect the value of our entire calibration program when we decide how often to calibrate. Unfortunately, we don’t always have enough historical calibration results data to predict the best calibration interval with a high degree of confidence. Although Bayesian statistical theory provides a method for including independent data sources to supplement calibration results data, limited empirical evidence exists to assess how well Bayesian statistics predicts measurement reliability. The literature has no example that measures how well subjective information estimates measurement reliability
{"title":"The Value of Subjective Information: An Empirical Assessment","authors":"S. Dwyer","doi":"10.51843/wsproceedings.2018.16","DOIUrl":"https://doi.org/10.51843/wsproceedings.2018.16","url":null,"abstract":"Metrology engineers want technically correct answers. Managers want to make decisions that trade off cost against product value. Calibration personnel want their work to count. Calibration intervals drive measurement reliability, the calibration budget, and the value of every calibration. We affect the value of our entire calibration program when we decide how often to calibrate. Unfortunately, we don’t always have enough historical calibration results data to predict the best calibration interval with a high degree of confidence. Although Bayesian statistical theory provides a method for including independent data sources to supplement calibration results data, limited empirical evidence exists to assess how well Bayesian statistics predicts measurement reliability. The literature has no example that measures how well subjective information estimates measurement reliability","PeriodicalId":120844,"journal":{"name":"NCSL International Workshop & Symposium Conference Proceedings 2018","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126173948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.51843/wsproceedings.2018.12
D. Dubro
Anyone who is conversant with the standard G.U.M. method for calculating uncertainties using the so-called “Law for the Propagation of Uncertainties” knows that it is important to include any correlations among the components in the calculation. We have all seen simple examples of correlation, such as the comparison of height and weight in a sample of people. But in calculating an uncertainty budget with correlated uncertainties, it is not possible to measure the correlation coefficients. They have to be estimated. It is a fact that any two instruments which are not perfect, will have errors which will be correlated. Unless one has a perfect calibration standard, the correlation coefficient cannot be measured. This paper deals with a practical example calibrating thread wires in which 18 short term measurements are recorded using the same micrometer. During the short time of the calibration, many of the Type B uncertainties will be constant, although they will most likely vary tomorrow, next week and next year. This paper will show a method for estimating the correlation coefficient for uncertainties for calculated parameters such as roundness, taper and the master average.
{"title":"Practical Correlation in Repetitive Measurements","authors":"D. Dubro","doi":"10.51843/wsproceedings.2018.12","DOIUrl":"https://doi.org/10.51843/wsproceedings.2018.12","url":null,"abstract":"Anyone who is conversant with the standard G.U.M. method for calculating uncertainties using the so-called “Law for the Propagation of Uncertainties” knows that it is important to include any correlations among the components in the calculation. We have all seen simple examples of correlation, such as the comparison of height and weight in a sample of people. But in calculating an uncertainty budget with correlated uncertainties, it is not possible to measure the correlation coefficients. They have to be estimated. It is a fact that any two instruments which are not perfect, will have errors which will be correlated. Unless one has a perfect calibration standard, the correlation coefficient cannot be measured. This paper deals with a practical example calibrating thread wires in which 18 short term measurements are recorded using the same micrometer. During the short time of the calibration, many of the Type B uncertainties will be constant, although they will most likely vary tomorrow, next week and next year. This paper will show a method for estimating the correlation coefficient for uncertainties for calculated parameters such as roundness, taper and the master average.","PeriodicalId":120844,"journal":{"name":"NCSL International Workshop & Symposium Conference Proceedings 2018","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125867433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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