• Journal of Sensor Science and Technology
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• v.30 no.5
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• pp.349-356
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• 2021

The Korea Research Institute of Standards and Science (KRISS), a National Metrology Institute of Korea, participated in the second-round of the international key comparison CCT-K7.2021 of triple point of water (TPW) cells. For the key comparison, three TPW cells, one of which had been used in the old CCT-K7 comparison, were assigned as the national standard of the TPW. The temperature difference (ΔT) between the average of the new and old national standards and ΔT between the new national standard and the transfer standard were measured. The comparison between the new and old national standards indicated a temperature increase of 69.5 µK after both the standards were corrected for the isotopic composition. The uncertainty of the national standard of the TPW temperature was 28 µK, and the uncertainty of ΔT was 14 µK. Three aspects of improvements in the new comparison compared to the old one were noted: (1) inclusion of two quartz cells in the national standard strengthens its long-term stability; (2) the standard deviation associated with the measurement of ΔT was reduced from 21 µK to 9.6 µK; (3) and the measured immersion profile of the TPW cells was much closer to the theoretically predicted dependence.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.606-608
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• 1999

Mutual Recognition Agreement(MRA) between national metrology institutes is started on October 1999 and International Key Comparison is essentially to be used as technical basis for the agreement. High resistance is one of the Key Comparison and high resistance measurement system is established in KRISS for the purpose of the Key Comparison. Total combined uncertainty of the system is about 4ppm in $10M{\Omega}$ and 8ppm in $1G{\Omega}$. With the system, the difference of comparison results for $10M{\Omega}$ and $1G{\Omega}$ among KRISS, VNIIM in Russia and NIM in China is agreed about 6ppm within total combined uncertainty of three institutes.

• Journal of the Korean Magnetics Society
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• v.14 no.6
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• pp.201-206
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• 2004

The AC-DC magnetic field standard systems were constructed for the calibration of magnetometers for low magnetic field and the tests for low magnetic field characteristics of sensors and materials. In the range of 1 mT, the expanded uncertainty of dc is 8${\times}$10$\^$-6/, ac uncertainties are 0.16% in 0.1～1 kHz, 0.26% in 1～5 kHz, and 0.44% in 5～20 kHz. We have been participated in international key comparison(KC) to achieve the equality and the mutual agreement between standard institutes for the results of calibrations and tests. KRISS participating in ac-dc magnetic flux density of KC got equal level of uncertainty results compare with the advanced nations. It confirm that measurement ability of magnetic flux density is high level in the world.

• Journal of Sensor Science and Technology
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• v.13 no.2
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• pp.114-120
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• 2004

The $Comet{\acute{e}}$ Consultatif de $Thermom{\acute{e}}trie$ (CCT) under the Comete International des Poids et Measures (CIPM) has decided to perform the Key Comparison (KC) for triple point of water cells used as a reference fixed point of thermometry at the 21st meeting held at November 2001, and the Bureau International des Poids et Measures (BIPM) has been nominated as a KC coordinator. According to the KC protocol prepared by BIPM, KRISS performed the KC experiments and evaluate a uncertainty. The temperature difference between two reference cells for the Korea Research Institute of Standards and Science (KRISS) and a test cell for the transfer standard, which is moved to BIPM was 0.024 mK and the combined standard uncertainty evaluated 0.055 mK.

• The Journal of the Acoustical Society of Korea
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• v.24 no.4
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• pp.194-201
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• 2005

Since the necessity for the accurate measurement in the field of acoustics, vibration, and ultrasound was internationally increased, CCAUV (Consultative Committee for Acoustics , Ultrasound and Vibration) was created by the CIPM (International Committee for Weights and Measures) in 1998. One of the first activities of CCAUV is the key comparison on 1' standard microphones. The key comparison was done from April. 1999 to April. 2001 and 12 NMIs(National Metrology Institutes) including KRISS (Korea Research Institute of Standards and Science) were participated. The pilot laboratory was the National Physical Laboratory(NPL). The traveling standards were two LSIP(Laboratory Standard 1' Pressure Type) microphones specified in IEC 61094-1 and the calibration frequency ranges covers from 63Hz to 8kHz. In this paper, the analyzed results in the final report were summarized.

• Proceedings of the Korean Magnestics Society Conference
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• 2004.06a
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• pp.38-39
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• 2004

• East Asian mathematical journal
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• v.25 no.3
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• pp.279-297
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• 2009

This paper discusses the key differences and common themes among three major assessments of pre-college mathematics learning: Program for International Student Assessment (PISA), Third International Mathematics and Science Study Repeat (TIMSS-R), and National Assessment of Educational Progress (NAEP).

• Journal of Technology Innovation
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• v.12 no.2
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• pp.21-46
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• 2004

Focusing on a product, this paper reconstructs the concept of technological systems first introduced by Carlsson and Stankiewicz (1991). Based on the model and our earlier works, we compare the salient features of technological systems for computer numerically controlled (CNC) machine tools in Korea, Sweden, and the United States.. We also try to measure the performance of the systems in an international comparison. Major findings are as follows: (1) The length of 'learning period' for local (national) technological system is substantial, even though it is a catching-up case. (2) The key success factor of the technological system appears to be the connectivity among various actors or infrastructures, rather than just the existence or formation of those. (3) In three countries' experience, the government played an important role in the formation of each own technological system. (4) The performance of Korea's technological system for CNC machine tools during the past two decades(1981-97) seems to be better than that of Sweden and the U.S. Lastly, many policy implication are presented.

• Journal of Korean language education
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• v.29 no.2
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• pp.25-48
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• 2018

The aim of this study was to analyze research trends in the fields of Korean Language and Literature, Korean Language Education, and Korean Language Education as a Foreign Language. To this end, key words were extracted from 29,470 academic theses published between 2000 and 2017. The results of the analysis are as follows. First, in the field of Korean Language and Literature, there is greater quantity in studies about Korean language than about literature, and starting from 2010, there was an increase in studies similar to those from the field of Korean Language Education as a Foreign Language. Next, in comparison to the other fields, the field of Korean Language Education has greater variance in its research theme-in particular, numerous studies related to the site of education. Finally, the field of Korean Language Education has the following trends: a) there are copious studies focused on Korean language learners in comparison to other fields, b) there are a greater number of studies focused on culture, and c) the key words change by time period which suggest that research demands transformed over time. Overall, a total of 64 highest frequency key words from the three academic fields were investigated. Of these, 22 were common key words and 42 were differential key words. In this way, it was possible to illuminate the identity of each field.

• Journal of Sensor Science and Technology
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• v.31 no.6
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• pp.448-454
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• 2022

An intralaboratory comparison of the realization of the triple-point temperature of mercury, which is defined as -38.8344℃ on the international temperature scale of 1990 (ITS-90), was conducted at the Korea Research Institute of Standards and Science (KRISS), the national metrology institute of Korea. To this end, four triple-point-of-mercury cells were compared using the resistance ratio measurement of a standard platinum resistance thermometer to validate the calibration results obtained using the triple-point-of-mercury cells at KRISS. The triple-point temperatures of all the four cells, one of which is designated as the national standard cell, were within 0.3 mK of the national standard. Based on 13 experiments on the four triple-point-of-mercury cells, the uncertainty in the comparison of the triple-point-of-mercury cells was 0.08 mK, and the uncertainty in the realization of the triple-point temperature of mercury was 0.19 mK. The results of the intralaboratory comparison validated that utilizing any of the four triple-point-of-mercury cells would result in the realization of a temperature within 0.3 mK of the average value determined by two key international comparisons for the realization of -38.3844℃ following the ITS-90.