• Title/Summary/Keyword: National Measurement Standards

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Development of relative radiometric calibration system for in-situ measurement spectroradiometers (현장관측용 분광 광도계의 상대 검교정 시스템 개발)

  • Oh, Eunsong;Ahn, Ki-Beom;Kang, Hyukmo;Cho, Seong-Ick;Park, Young-Je
    • Korean Journal of Remote Sensing
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    • v.30 no.4
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    • pp.455-464
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    • 2014
  • After launching the Geostationary Ocean Color Imager (GOCI) on June 2010, field campaigns were performed routinely around Korean peninsula to collect in-situ data for calibration and validation. Key measurements in the campaigns are radiometric ones with field radiometers such as Analytical Spectral Devices FieldSpec3 or TriOS RAMSES. The field radiometers must be regularly calibrated. We, in the paper, introduce the optical laboratory built in KOSC and the relative calibration method for in-situ measurement spectroradiometer. The laboratory is equipped with a 20-inch integrating sphere (USS-2000S, LabSphere) in 98% uniformity, a reference spectrometer (MCPD9800, Photal) covering wavelengths from 360 nm to 1100 nm with 1.6 nm spectral resolution, and an optical table ($3600{\times}1500{\times}800mm^3$) having a flatness of ${\pm}0.1mm$. Under constant temperature and humidity maintainance in the room, the reference spectrometer and the in-situ measurement instrument are checked with the same light source in the same distance. From the test of FieldSpec3, we figured out a slight difference among in-situ instruments in blue band range, and also confirmed the sensor spectral performance was changed about 4.41% during 1 year. These results show that the regular calibrations are needed to maintain the field measurement accuracy and thus GOCI data reliability.

Experimental Study on Ignition and Explosion Hazard by Measuring the Amount of Non-volatile (NVR) and Explosion Limit of Biodiesel Mixture (바이오디젤 혼합물의 가열잔분측정과 폭발한계 측정을 통한 발화 및 폭발위험성에 대한 실험적인 연구)

  • Kim, Ju Suk;Koh, Jae-Sun
    • Journal of the Society of Disaster Information
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    • v.18 no.1
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    • pp.182-193
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    • 2022
  • Purpose: By measuring and evaluating the risk of biodiesel through non-volatile residue (NVR) and flash point and explosion limit measurement at a specific temperature according to ASTM test standards, the risk of chemical fire causative substances is identified and a universal evaluation method By derivation and securing the risk-related data of the material, it can be used for the identification and analysis of the cause of the fire, and it can be applied to the risk assessment of other chemical substances Method: In order to measure the risk of biodiesel, it was measured using the non-volatile residue(NVR) measurement method, which measures how much flammable liquid is generated at a specific temperature. Heating was tested by applying KS M 5000: 2009 Test Method 4111. In addition, the flash point was measured using the method specified in ASTM E659-782005, and the energy supply method was measured using the constant temperature method. In addition, the explosion limit measurement was conducted in accordance with ASTM E 681-04 「Standard test method for concentration limits of flammability of chemicals(Vapors and gases)」 test standard. Result: As a result of checking the amount of combustible liquid by the non-volatile residue (NVR)measurement method, the non-volatile residue(NVR) of general diesel when left at 105±2℃ for 3 hours was about 30% (70% of volatile matter) and about 4% of biodiesel. In addition, similar results were obtained for the non-volatile residue(NVR)heating temperature of 150±2℃, 3 hours and 200±2℃ for 1 hour, and white smoke was generated at 200℃ or higher. In addition, similar values were obtained as a result of experimentally checking the explosion (combustion) limits of general diesel, general diesel containing 20% biodiesel, and 100% biodiesel. Therefore, it was confirmed that the flammability risk did not significantly affect the explosion risk. Conclusion: The results of this study suggested the risk judgment criteria for mixtures through experimental research on flammable mixtures for the purpose of securing the effectiveness, reliability, and reproducibility of the details of the criteria for determining dangerous substances in the existing Dangerous Materials Safety Management Act. It will be possible to provide reference data for the judgment criteria for flammable liquids that are regulated in the field. In addition, if the know-how for each test method is accumulated through this study, it is expected that it will be used as basic data in the research on risk assessment of dangerous substances and as a basis for research on the determination of dangerous substances.

A Practical Method to Quantify Very Low Fluxes of Nitrous Oxide from a Rice Paddy (벼논에서 미량 아산화질소 플럭스의 정량을 위한 실용적 방법)

  • Okjung, Ju;Namgoo, Kang;Hoseup, Soh;Jung-Soo, Park
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.24 no.4
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    • pp.285-294
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    • 2022
  • In order to accurately calculate greenhouse gas emissions in the agricultural field, Korea has been developing national-specific emission factors through direct measurement of gas fluxes using the closed-chamber method. In the rice paddy, only national-specific emission factors for methane (CH4) have been developed. It is thus necessary to develop those for nitrous oxide (N2O) affected by the application of nitrogen fertilizer. However, since the concentration of N2O emission from rice cultivation is very low, the QA/QC methods such as method detection and practical quantification limits are important. In this study, N2O emission from a rice paddy was evaluated affected by the amount of nitrogen fertilizer, by taking into account both method detection and practical quantification limits for N2O concentration. The N2O emission from a rice paddy soils affected by the nitrogen fertilizer application was estimated in the following order. The method detection limit (MDL) of N2O concentration was calculated at 95% confidence level based on the pooled standard deviation of concentration data sets using a standard gas with 98 nmol mol-1 N2O 10 times for 3 days. The practical quantification limit (PQL) of the N2O concentration is estimated by multiplying 10 to the pooled standard deviation. For the N2O flux data measured during the rice cultivation period in 2021, the MDL and PQL of N2O concentration were 18 nmol mol-1 and 87 nmol mol-1, respectively. The measured values above the PQL were merely about 12% of the total data. The cumulative N2O emission estimated based on the MDL and PQL was higher than the cumulative emission without nitrogen fertilizer application. This research would contribute to improving the reliability in quantification of the N2O flux data for accurate estimates of greenhouse gas emissions and uncertainties.

Comparison of General Test Methods of Various Organs on Synthetic Food Colors (여러 기관의 일반시험법에 의한 식용 타르색소의 규격 비교 시험)

  • Shin Dong-Hwa;Kim Yong-Suk;Lee Young-Hwan;Bang Jeong-Ho;Om Ae-Son;Shin Jae-Wook;Lee Tal-Soo;Hong Ki-Hyoung;Park Sung-Kwan;Choi Duck-Jang;Kim Hee-Yun
    • Journal of Food Hygiene and Safety
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    • v.20 no.1
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    • pp.64-68
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    • 2005
  • An analytical method of nine synthetic foods colors in Korea, Japan, Joint FAO/WHO Expert Committee of Food Additives (JECFA), and USA were compared. Contents of water insoluble matter in synthetic food colors tested were not different by general test methods of various organs. Contents of chloride and sulfate salts in Food Green No.3, Food Red No.3, Food Blue No.2, and Food Yellow No.4 slightly differed in various methods, and but up to the standard, and general test methods of JECFA and USA needed far more time. For the measurement of arsenic contents in food colors, colorimetric method in Korea and Japan, and silver diethyldithiocarbamate colorimetric method in USA and JECFA were used, but the standards of them were different. Content of heavy metals was up to the standard, but the methods were used colorimetric method in Korea, atomic absorption method in Japan, and both methods in JECFA and USA.

A Validation Study of Retrospective Pre-post Testin the Affective Domain in Science Learning:for Scientifically Gifted Elementary Students (과학학습의 정의적 영역에서 사전-사후 통합 검사 설계의 타당화 연구: 과학영재를 대상으로)

  • Lim, Chae-Seong;Park, Hyoung-Min
    • Journal of Korean Elementary Science Education
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    • v.36 no.3
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    • pp.219-226
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    • 2017
  • In this study, the reliability and validity of the retrospective pre-post test were analyzed in order to solve the problem of traditional pre-post test including response shift bias. Samples of the study were 162 elementary school students who are studying at the S university gifted education center in Seoul. Before completion of the field trip, we conducted pre test of science-related attitudes. After completion of the field trip, respondents were asked to compare their responses of pre and post science-related attitudes to quantitatively analyze the commonalities and differences of the two tests. To find out more characteristics, qualitative data such as daily records and interview were also gathered and analyzed. The major results of the study are as follows. First, for the paired t-test, there was no statistically significant difference between separate pre-test scores and retrospective pre-test. There was a very high correlation between the separate pre-test scores and the retrospective pre-test. Second, there were significant differences in all seven sub-factors of science-related attitudes between the retrospective pre-test and the post-test. Third, the separate pre-test scores showed a slightly higher tendency than the retrospective pre-test scores. This suggests that the response shift bias appears when it is performed the separate pre-test in affective domain. As a result of the interview, it was found that the evaluation standards of separate pre-test did not match with those of post-test. Forth, internal consistency reliability of the retrospective pre-test was higher than that of the separate pre-test. However, there were significant differences in six factors of science-related attitudes excluding the 'social implications of science' between the separate pre-test and the post-test. Based on these results, the retrospective pre-post test design provides simplicity and convenience to both respondents and investigators, as it is done with one test. The retrospective pre-post test design can be regarded as a valid design for the self-report measurement of affective domain on a single experimental group.

Comparison of General Test Methods of Various Organs on Synthetic Food Colors (여러 기관의 일반시험법에 의한 식용 타르색소의 규격 비교 시험)

  • Shin Dong-Hwa;Kim Yong-Suk;Lee Young-Hwan;Bang Jeong-Ho;Om Ae-Son;Shin Jae-Wook;Lee Tal-Soo;Hong Ki-Hyoung;Park Sung-Kwan;Choi Jang-Duck;Kim Hee-Yun
    • Journal of Food Hygiene and Safety
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    • v.19 no.4
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    • pp.171-175
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    • 2004
  • An analytical method of nine synthetic food colors in Korea, Japan, Joint FAO/WHO Expert Committee of Food Additives (JECFA), and USA were compared. Contents of water insoluble matter in synthetic food colors tested were not different by general test methods of various organs. Contents of chloride and sulfate salts in Food Green No.3, Food Red No.3, Food Blue No.2, and Food Yellow No.4 slightly differed in various methods, and but up to the standard, and general test methods of JECFA and USA needed far more time. For the measurement of arsenic contents in food colors, colorimetric method in Korea and Japan, and silver diethyldithiocarbamate colorimetric method in USA and JECFA were used, but the standards of them were different. Content of heavy metals was up to the standard, but the methods were used colorimetric method in Korea, atomic absorption method in Japan, and both methods in JECFA and USA.

A Study on the Sasang Constitutional Characteristics by Obesity Grade (비만도에 따른 사상체질별 체형 특성 분석)

  • Yeo, Hye-Rin;Kim, Kyu-Kon;Lee, Myung-Hee;Park, Yoon-Chang;Jeon, Soo-Hyung;Kwon, Suk-Dong;Jung, Sung-Il;Kim, Jong-Won
    • Journal of Sasang Constitutional Medicine
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    • v.20 no.1
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    • pp.89-99
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    • 2008
  • 1. Objectives The objective of this study is to offer some standards for the distinction of Sasang Constitutions through analyzing the characteristics of their body shapes that are classified by BMI. 2. Methods The subject of this study were 1341 female and 927 male patients who aged from 17 to 80 in Seoul, Pusan, Daeku and Jeonju. They were treated with Sasang Constitutional medicine. 8 circumferences, 5 widths, weight, height of their body were measured with measuring tape, large sliding caliper, scale and anthropometer. Collected 15 anthropometric datas were analyzed by Analysis of Contingency table, ANOVA and Duncan test. 3. Results (1) The Body shapes according to obesity grade are classified Underweight type that BMI is less than 18.5, Normal weight type that BMI is $18.5{\sim}23.0$ and Overweight type that BMI is mote than 23.0. (2) Soeumin represents Underweight type and Taeeumin represents Overweight type regardless of gender differences. Soeumin stands for Normal weight type in women and Soyangin stands for Normal weight type in men. (3) In case of Underweight type, 13 measurements are not suitable to estimate Sasang Constitutions regardless of gender differences. (4) In case of Normal weight type, 12 measurements except for W3 in women and W7 in men are suitable to estimate Sasang Constitutions. And there are no gender differences in Soyangin and Soeumin, but there are gender differences in Taeyangin and Taeeumin. (5) In case of Overweight type, 9 measurements except for C2, C5, C6, W7 in women and 12 measurements except for W3 in men are suitable to estimate Sasang Constitutions. And there are no gender differences in 4 Sasang Constitutions. 4. Conclusions From the above results, we have to consider not only gender differences and age groups but also obesity grade when we distinguish Sasang Constitutions.

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The Development of Assessment Method for Parking Lot Remodeling Alternative Adopted Asset Management Technique (자산관리 기법을 적용한 주차장 리모델링 대안평가 기법 개발)

  • Yu, Yongsin;Lee, Chansik
    • Korean Journal of Construction Engineering and Management
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    • v.18 no.3
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    • pp.52-62
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    • 2017
  • The purpose of this study is to develope an assessment method for parking lot remodeling alternative by adopting the asset management technique. In order to identify the Level of Service(LOS) and the Evaluation Measurement(EM), literatures was implemented which documented the consideration of parking lot plan, needs of the apartments' tenant, and various design standards. In addition, the authors conducted a three-time delphi survey for the identified 5 LOS and 19 EM to evaluate suitability and necessity of them and to collect additional opinion of experts. The LOS of parking lot were categorized into 5 areas such as Environmental effect and Convenience, Accessibility and so on. The 19 EM were determined to estimate the LOS quantitatively. The researchers analyzed the degree of importance of LOS and EM by using the Analytic Hierarchy Process (AHP) method. But construction cost was excepted from the analysis, because it is used as an independent variable in alternative assessment. In conclusion, the authors proposed the estimation criteria for EM, and the method and process for alternative assessment be performed to benefit-cost analysis using the LOS variation and construction cost. The assessment method for parking lot remodeling alternative was demonstrated effective to assess the parking lot remodeling alternative by case-study. This study has a academic significance by adopting the asset management techniques in the area of the parking lot remodeling. And the assessment method is expected to help deciding a reasonable remodeling alternative of parking lot, as it ensures the diversity for remodeling of the parking lot and reflects the needs of the occupant.

Low Frequency Noise and It's Psychological Effects

  • Eom, Jin-Sup;Kim, Sook-Hee;Jung, Sung-Soo;Sohn, Jin-Hun
    • Journal of the Ergonomics Society of Korea
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    • v.33 no.1
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    • pp.39-48
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    • 2014
  • Objective: This entire study has two parts. Study I aimed to develop a psychological assessment scale and the study II aimed to investigate the effects of LFN (low frequency noise) on the psychological responses in humans, using the scale developed in the study I. Background: LFN is known to have a negative impact on the functioning of humans. The negative impact of LFN can be categorized into two major areas of functioning of humans, physiological and psychological areas of functioning. The physiological impact can cause abnormalities in threshold, balancing and/or vestibular system, cardiovascular system and, hormone changes. Psychological functioning includes cognition, communication, mental health, and annoyance. Method: 182 college students participated in the study I in development of a psychological assessment scale and 42 paid volunteers participated in the study II to measure psychological responses. The LFN stimuli consisted of 12 different pure tones and 12 different 1 octave-band white noises and each stimulus had 4 different frequencies and 3 different sounds pressure levels. Results: We developed the psychological assessment scale consisting of 17 items with 3 dimensions of psychological responses (i.e., perceived physical, perceived physiological, and emotional responses). The main findings of LFN on the responses were as follows: 1. Perceived psychological responses showed a linear relation with SPL (sound pressure level), that is the higher the SPL is, the higher the negative psychological responses were. 2. Psychological responses showed quadric relations with SPL in general. 3. More negative responses at 31.5Hz LFN than those of 63 and 125Hz were reported, which is deemed to be caused by perceived vibration by 31.5Hz. 'Perceived vibration' at 31.5Hz than those of other frequencies of LFN is deemed to have amplified the negative psychological response. Consequently there found different effects of low frequency noise with different frequencies and intensity (SPL) on multiple psychological responses. Conclusion: Three dimensions of psychological responses drawn in regard to this study differed from others in the frequencies and SLP of LFN. Negative psychological responses are deemed to be differently affected by the frequency, SPL of the LFN and 'feel vibration' induced by the LFN. Application: The psychological scale from our study can be applied in quantitative psychological measurement of LFN at home or industrial environment. In addition, it can also help design systems to block LFN to provide optimal conditions if used the study outcome, .i.e., the relations between physical and psychological responses of LFN.

Validation of the Korean Version of the Perfectionism Inventory (PI) for Gifted Students (한국판 PI(Perfectionism Inventory)의 타당화 연구: 영재학생을 대상으로)

  • Yoon, So-Young;Han, Ki-Soon
    • Journal of Gifted/Talented Education
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    • v.25 no.5
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    • pp.749-765
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    • 2015
  • This study is aimed at validation of the Korean Version of the Perfectionism Inventory which was developed by Hill et al.(2004). To do so, exploratory factor analysis and confirmatory factor analysis with 167 science high school and 161 middle school gifted students were conducted. It appeared 6 factor structure consisting of 'Self-Evaluative Perfection Strivings', 'Parental Pressure', 'Planfulness', 'Striving for Excellence', 'High Standards for Others', and 'Organization', which does not support 8 factor of the original scale. As a result, Cronbach's ${\alpha}$ ranged from .78 to .92 for subscale of PI and .93 for the total scale. The fit of measurement model was found to be ${\chi}^2=1257.618$ (df=792, p=.00), TLI=.903, CFI=.911, RMSEA=.047, indicating most of fit indexes were acceptable. Also, the validity of the scale was examined by the correlations between the PI and MPS. PI Korean version is significant to confirm the factor structure and validity of perfectionism which was influenced by characteristics of gifted students and Korean culture. These results show that the PI is quite reliable and valid tool for measuring perfectionism for gifted students.