• 한국유체기계학회 논문집
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• 제7권1호
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• pp.24-29
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• 2004

The inter-comparison of standards is required to be recognized the calibration results. The sonic nozzle package is developed to do inter-comparison of the bell preyer used to calibrate many gas flow meters for industries. Four national metrology institutes (KRISS, CMS, CENAM, NEL) were participated in this inter-comparison. The deviation of calibration data from the average value was small at the low flow rate and large at the high flow rate, respectively At the high flow rate, the deviation was larger than the expected value from uncertainties asserted by NMIs. This means there are some problems in the uncertainty evaluation and experiment procedures in some of the participated NMIs.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2217-2219
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• 2005

In this paper, an inter-comparison test of lightning impulse reference measurement system between Korea and Japan is reported. At present, such a direct comparison test as the activity to sustain the traceability of the measurement system is generally proposed. Due to the inter-comparison test, ascertaining the grade of the measurement uncertainty and maintaining the level of reference system are accomplished.

• 한국대기환경학회지
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• 제23권6호
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• pp.689-698
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• 2007

Particular attention is paid to the validity of PM-10 measurement using beta attenuation method. In this study, the inter-comparison studies were undertaken for PM-10 sampler with different measuring methods. The three beta attenuation monitoring instruments (BAM1020, FH C-14, and DIGS-150) and filter based gravitational method using High Volume Air Sampler were collocated and mass concentrations were compared from August to November, 2006. The results of the investigation show that beta attenuation monitoring instruments are comparable with gravitational method within 10% of measurement error. For specific conditions under high humidity and high concentrations, the inter-comparison results also showed a relatively good agreement and this can be explained as the effect of inlet heating of beta attenuation instrument. Subsequently, this study shows that beta attenuation monitoring instruments can be equivalently used with reasonable validity when compared gravimetric method.

• 환경영향평가
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• 제19권4호
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• pp.431-441
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• 2010

In this study, inter-comparison for PM-2.5 was undertaken. The PM-2.5 mass concentrations using the gravimetric and beta-attenuation methods were compared during the winter in 2007. Two different types of conventional filter-based measurements (Cyclone type and Impactor type) were also collocated and the measurement data was compared with each other. As a result, continuous PM-2.5 data using beta attenuation method show a comparable mass concentration with gravimetric measurement when the inlet of beta-gauge sampler is heated. The results also showed that the cyclone type shows a little high PM-2.5 concentration than Impactor type. In all the sampling cases, the correlations between measurement methods are high. Subsequently, this study suggests that highly correlated relationship between PM-2.5 measurement instruments can be obtained through the inter-comparison results based on filterb-ased gravimetric method and more intensive measurement and theoretical studies are needed in order to clarify the measurement errors for different sampler types.

• 환경분석과 독성보건
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• 제21권4호
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• pp.229-236
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• 2018

In this study, inter-laboratory comparison was done using elemental analyzer-isotope ratio mass spectrometers (EA-IRMSs) to determine carbon and nitrogen contents as well as stable carbon and nitrogen isotopic compositions (${\delta}^{13}C$ and ${\delta}^{15}N$) of five environmental samples containing lake and marine sediments, higher plant leaves, and fish muscle, and one organic analytical standard (Protein (Casein) Standard OAS). Five national laboratories participated in this comparison study, and each laboratory analyzed all five samples and the analytical standard. Results showed that variations in total organic carbon (TOC) and total nitrogen (TN) contents as well as ${\delta}^{13}C_{TOC}$ and ${\delta}^{15}N_{TN}$ values among the laboratories were large compared to the analytical uncertainties. The results highlighted the inhomogeneity of the test samples and thus, the need to select suitable standard reference materials for future inter-laboratory studies. Further inter-laboratory comparison exercises could promote good measurement practices in the acquisition of stable carbon and nitrogen isotopic composition data.

• Nuclear Engineering and Technology
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• 제54권7호
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• pp.2599-2605
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• 2022

The Korea Retrospective Dosimetry network (KREDOS) performed an inter-laboratory comparison to confirm the harmonization and reliability of the results of retrospective dosimetry using mobile phone. The mobile phones were exposed to ¹⁹²Ir while attached to the human phantoms in the field experiment, and the exposure doses read by each laboratory were compared. This paper describes the reference dosimetry performed to present the reference values for inter-comparison and to obtain additional information about the dose distribution. Reference dosimetry included both measurement using LiF:Mg,Cu,Si and calculation via MCNP simulation to allow a comparison of doses obtained with the two different methodologies. When irradiating the phones, LiF elements were attached to the phones and phantoms and irradiated at the same time. The comparison results for the front of the phantoms were in good agreement, with an average relative difference of about 10%, while an average of about 16% relative difference occurred for the back and side of the phantom. The differences were attributed to the different characteristics of the physical and simulated phantoms, such as anatomical structure and constituent materials. Nevertheless, there was about 4% of under-estimation compared to measurements in the overall linear fitting, indicating the calculations were well matched to the measurements.

• 한국군사과학기술학회지
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• 제10권2호
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• pp.100-106
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• 2007

In this paper, the performance of OFDM(Orthogonal Frequency Division Multiplexing) and FMT(Filtered Multi-tone) Systems is compared under jamming environment. Two systems are multi-carrier systems to improve data rates. Through the comparison of two systems under jamming environment, the characteristics and strong/weak points of each system are analyzed.

• 센서학회지
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• 제18권1호
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• pp.86-94
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• 2009

Temperature measurement capability was inter-compared using the transfer standard platinum resistance thermometers(SPRT) among four laboratories of KRISS. The transfer SPRTs were primarily calibrated at the triple point of water and Ga melting point, then used at inter-comparison experiment. Temperature difference of calibration value between temperature laboratory and length laboratory at $20^{\circ}C$ was -0.7 mK and +2.4 mK at density laboratory. Temperature measured near $20^{\circ}C$, $25^{\circ}C$ and $30^{\circ}C$ at fluid flow laboratory was deviated by $34.2{\sim}80.4\;mK$ from the calibration values of the transfer SPRT. Ga melting points was inter-compared among three laboratories, and the difference of Ga melting points against the standard Ga melting point of temperature laboratory were $0.03{\sim}0.54\;mK$ at length laboratory and 0.02 mK at density laboratory.

• Ocean and Polar Research
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• 제38권3호
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• pp.247-257
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• 2016

The inter-comparison project for seawater salinity measurements, in which 25 laboratories from 16 countries took part, was conducted by JCOMM (Joint WMO/IOC Technical Commission for Oceanography and Marine Meteorology) for the first time in 2014. Two seawater samples of different salinity values ranging from 30-35 and 20-25 for Sample A and Sample B respectively and which had sufficient homogeneity and stability were distributed to all participants. Participants measured the salinity in their own laboratories at least 3 times and reported the results. Statistical treatments were applied to the results to assess discrepancies among laboratories. 20 out of the 25 laboratories used laboratory salinometers and statistics for this group were denoted as belonging to group ${\alpha}$; while 5 out of the 25 laboratories used hand-held measuring instruments and statistics for this group were denoted as belonging to group ${\beta}$. Bias described as discrepancy among laboratories in group ${\alpha}$ was within ${\pm}0.001$ and expanded uncertainty (k = 2) was in the vicinity of 0.002. The bias and the uncertainty of Korea Institute of Ocean Science and Technology (KIOST), in group ${\alpha}$, were 0.000 and 0.002, respectively. The biases of group ${\beta}$ were greater than group ${\alpha}$ because of constraints related to instrument accuracy. Biases from 3 laboratories in group ${\beta}$ exceed the accuracy specification of the corresponding instruments. Considering that the uncertainty of Standard Seawater (SSW) is of the order 0.001 to 0.002, the inter-comparison results show that 16 laboratories among the 25 laboratories made high quality measurements, largely indistinguishable from one another.

• Earthquakes and Structures
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• 제17권1호
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• pp.1-15
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• 2019

In the structures with high level of ductility, the earthquake energy dissipation in structural components is an important factor that describes their seismic behavior. Since the connection details play a major role in the ductile behavior of structure, in this paper, the seismic response of 3-, 5- and 8-story steel special moment frames (SMFs) is investigated by considering the effects of panel zone modeling and the influence of forward-directivity near-field ground motions. To provide a reasonable comparison, selected records of both near and far-field are used in the nonlinear time-history analysis of models. The results of the comparison of the median maximum inter-story drift under excitation by near-field (NF) records and the far-field (FF) ground motions show that the inter-story drift demands can be obtained 3.47, 4.86 and 5.92 times in 3-, 5- and 8-story structures, respectively, undergoing near-field earthquakes.