• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.669-672
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• 2002

Establishment of the Quantum Hall Resistance(QHR) Standard as national resistance standard using a room temperature DCC resistance bridge is described. A simple method are used to obtain the current dependence and error of 10: 1 ratio of the bridge instead of the method using a cryogenic resistance bridge. Measurement uncertainty of the system is estimated as $0.14{\times}10^{-6}$ and it is confirmed that the QHR standard is agreed well with the QHR of other NMIs using the cryogenic resistance bridge within the uncertainty, More improvement about performance of the QHR device and 10: 1 ratio accuracy is still under progress.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.155-158
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• 2008

In this study we compared corrosion resistance tests which were carried out according to the national technique standard and the UL standard to ensure the reliability of smoke detectors in foul weather. The sensitivity of smoke detectors became so blunt that the least operational smoke concentration was a maximum change of 13% in the national technique standard, while it was a maximum change of 145% in the UL standard. As a result of this study the test method of corrosion resistance was made an objective evaluation in the national technique standard. Therefore it could be said that a basis of developing the test method of corrosion resistance was prepared for our country.

• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.185-189
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• 2012

While there is no standards on slip risk for contaminants on surface, glycerol is described in standard contaminant for measuring coefficient of friction(COF) and slip resistance such as ISO 13287. But that is just used to measure the slip resistance of surface materials and shoes not to evaluate the contaminant materials. Therefore the objective of this study was to find out the relationship between standard contaminant and the contaminants used usually at the workplaces. For this, some measurement criteria were acquired from the analysis based on biomechanics and kinetics of human gait during slips. The slip resistance according to viscosity of the contaminants was measured applying the criteria and slip probability was determined by the gait analysis. Some factors which should be considered when measuring the slip resistance were identified. The velocity, acceleration, contact time and contact pressure should be 1 m/sec, 10 $m/sec^2$, 350 kPa and less than 0.5sec respectively. The variation of viscosity according to temperature for working oils was different from that of standard contaminant. The static coefficient of friction (SCOF) of working oils was almost 0.5 times as large as the SCOF of standard contaminant. So it was assumed to be difficult to compare the contaminants at the workplaces with the glycerol as a standard contaminant for estimating the slip risk.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.1 s.232
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• pp.107-114
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• 2005

In order to analyze the elastic-plastic fracture behavior of a structure, the fracture resistance curve of the material should be known first. The standard CT specimen was used to obtain the fracture resistance curves of a piping system. However, it is known that the fracture resistance curve by the standard CT specimen is very conservative to evaluate the integrity of a structure. Also the fracture resistance curve is effected by the specimen geometry and the dimensions because of the constraint effect. The objective of this paper is to be certain the conservativeness of the fracture resistance curve by the standard CT specimen and to provide an additional safety margin. For these, the fracture tests using a real pipe specimen and the standard CT specimen test were performed. A 4-point bending jig was manufactured for the pipe test and the direct current potential drop method was used to measure the crack extension and the length for the pipe test. Also finite element analyses were performed with a CT specimen and a pipe in order to prove the additional safety margin. From the result of tests and analyses of the pipe and the standard CT specimen, it was observed that the fracture analysis with the standard CT specimen is conservative and the additional safety margin was proved.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.597-601
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• 2009

Green car such as a hybrid electrical vehicle and fuel cell vehicle is developed as a commercial target. UN/ECE/WP29 is developing GTR of HFCV and establishing the regulation and standard of electrical safety by ELSA. The regulation and standard about Electrical safety of vehicle are prescribed in ISO, UN/ECE, FMVSS, Japanese Attachment and so on, in case of insulation resistance is referred to keep more than 100/Vdc, 500/Vac. However, accurate method to measure insulation resistance agreeable to structure of vehicle does not exist now, it is actually that correctness of measurement drops according to the feature of battery and fuel cell stack. In this paper, the method to measure insulation resistance for protection against electrical shock by direct contact or indirect contact in Green Car will be indicated by making a comparison between the insulation measurement in standard of electrical safety and the experiment results for HEV and HFCV.

• Journal of the Korean Applied Science and Technology
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• v.22 no.3
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• pp.289-297
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• 2005

In order to improve resistant properties of water-borne acrylic pressure sensitive adhesives(PSAs) for automobiles, this study was carried out. Removable PSAs for automobiles were synthesized by emulsion polymerization of monomers, n-butyl acrylate(BA), n-butyl methacrylate(BMA), acrylonitrile(AN), acrylic acid(AA) and 2-hydroxyethyl methacrylate(2-HEMA), and AA and 2-HEMA could act as functional monomers for crosslink. Emulsion polymerization was carried out in a semi-batch type reactor. Water resistance, heat resistance, acid resistance, alkali resistance and smoke resistance were examined. As a result, water resistance increased with the amount of BMA, however, the effect of BMA content on the water resistance was insignificant at a range of over 14 wt%. The water resistance also increased with the amount of functional monomers, AA and 2-HEMA. The prepared PSAs satisfied all the standard for automobiles except heat resistance. However, the heat resistance comes nearly up to the standard. Also, acid resistance, alkali resistance and smoke resistance of the prepared PSAs satisfied with the standard.

• Journal of The Korea Institute of Healthcare Architecture
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• v.25 no.3
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• pp.75-83
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• 2019

Purpose: There are no clear criteria for slip performance in the BF certification process, so the evaluator relies on subjective judgments depending on the field situation. Physical criteria for determining the slip performance of various floor finishes are not clear. C.S.R., the only criterion currently being used to check slip performance, may raise questions about its coverage, feasibility and reliability. Method: For an analysis of domestic standards and status, KS L 1001, KS M 3510, and KS F 2375. External standards are analyzed for ADA Standard, ANSI Standard, and BS EN Standard. Analyze the test methods and evaluation criteria of O-Y-PSM, BPT, and the dynamic slip resistance test used in these criteria. It also presents an improvement plan for the rational presentation of standards. Results: To date, various kinds of test methods and measuring devices of the slip resistance coefficient have been developed, but there are not many ways to trust useful results related to user safety. Reliability and thoroughly verified test methods and criteria should be used to assess the slip performance of the floor. In order to improve the standard for the evaluation of slip performance in Korea, the existing standard should first be raised to the same level as the overseas standard, and the application of the discriminatory standard should be applied considering the characteristics and usage patterns of each space. Implication: Currently, Korean standards propose various test methods, but the proper use of test methods, scope and assessment criteria are not established, so improvement of the comprehensive standard is necessary.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.911-917
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• 2018

Influence of the adaptors on the calibration of $100{\mu}H$ inductance standard was studied as a function of torque, applied when tightening the standard inductor terminal with the adaptor. Two different homemade adaptors of BPO gold-plated brass (BPO-Au) and banana-copper (BN-Cu) were made for the connection between the LCR meter and the inductance standard. The measured inductance (L) of the standard inductor and the contact resistance ($R_C$) between the adaptor and the standard inductor terminal showed exponential decreases against the torque increase from $25cN{\cdot}m$ to $150cN{\cdot}m$. The measured L and the calculated equivalence series resistance ($R_S$) were dependent on the adaptor type as well as on the $R_C$. The results of the adaptor analysis imply that the BPO-Au adaptor with the lower $R_C$ is more suitable for the inductance calibration. The calculated inductance of $99.956{\mu}H$ corrected by subtraction of the adaptor inductance and the contact resistance contributions from the measured value using the BPO-Au adaptor agreed well with the certificate ($99.948{\mu}H$) of the PTB within the measurement uncertainty of $140{\mu}H/H$.

• Fire Science and Engineering
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• v.30 no.5
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• pp.67-73
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• 2016

This paper examined the structure, fire resistance of brass fittings type CSST employed in gas appliances and the reliability verification. Brass fittings of type CSST consisted of cladding, tubing, nut, clamp ring, socket, and ball valve. The applicable JIA standard regulates the maximum working pressure to be 4.2 kPa, which is the highest pressure of the relevant standards and the KS D 3625 stipulates the maximum pressure to be 3.24 kPa. With a normal product, the average resistance within the confidence interval was found to be $7.36m{\Omega}$. The average resistance within the confidence interval was $6.67m{\Omega}$ after the fire resistance tests. The analysis indicated that the AD was 1.584 and the standard deviation was 0.3972 with respect of a normal product. Compared to the normal product, however, the damaged product after the fire resistance test showed better features, such as an AD of 1.145 and a standard deviation of 0.2467. Moreover, the average resistance of the normal product was $7.359m{\Omega}$ and the standard deviation in histogram analysis was 0.3972. The average resistance of the damaged product after the fire resistance test in the histogram was $6.67m{\Omega}$ and the standard deviation was 0.2467.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.4
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• pp.105-111
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• 2018

Institutional inertia anti-disaster standard was presented mainly on the upper surface, it is necessary to improve to the soil type standard and uplift the resistance standard greenhouse that are vulnerable to strong winds. In this study, we carried out a field test using the load control method in order to evaluate the uplift resistance of continuous foundation of greenhouse with different depths of the rafters. Institutional inertia anti-disaster standard of greenhouse foundation did not protect the greenhouse structure from the damages caused by strong winds and heavy snow. Therefore, field tests for behavior characteristics of continuous greenhouse foundation were carried out to ensure stable facility cultivation. The field test condition was evaluated using different embedded depth as follows: 30cm, 40cm, 50cm and spacing 50cm, 60cm, 70 cm. As a result of the uplift resistance field tests using the load control method, the minimum uplift resistance was found to be over 90kg and uplift resistance displacement was 9.4mm. Uplift resistance of the continuous greenhouse foundation was in the range of 90-180 kg according to embedded depth and spacing. Using the test condition, there was no constant trend in the uplift resistance.