• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.11
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• pp.1925-1929
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• 2007

This paper is studied on a novel Electric Safety Protection Device (ESPD) of high speed for incapable operation of Earth Leakage Circuit Breaker (ELB) and Molded_case Circuit Breaker (MCCB) using the low voltage distribution line. The major causes of electrical fire are classified to short circuit fault, overload fault, electric leakage and electric contact failure. The occurrence factor of the fire is electric arc or spark accompanied with electrical faults. Residual Current Protective Device (RCD), that is ELB and MCCB, of high sensitivity type used at low voltage wiring cuts off earth leakage and overload, but the RCD can't cut off electric arc or spark to be a major factor of electrical fire. As the RCDs which are applied low voltage distribution panel are prescribed to rated breaking time about 30[ms] (KS C 4613), the RCDs can't perceive to the periodic electric arc or spark of more short wavelength level. To be improved on such problem, this research development is proposed to a novel ESPD of high speed to trip of distribution line on electric arc or spark due to electrical fire. Some experimental results of the proposed ESPD are confirmed to the validity of the analytical results.

• Journal of Soil and Groundwater Environment
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• v.10 no.6
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• pp.68-74
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• 2005

This study was carried out to evaluate the feasibility of field-scale sequential soil washing process for remediation on Kyongsangnamdo D mine soils which was heavily contaminated by arsonic. Arsenic concentration of untreated soils was $321\pm32mg/kg$. By applying the basic operating condition which was proposed from several pilot-scale experiments, arsenic concentration of treated soils was reduced 2.04 mg/kg ($99\%$ removal efficiency). We optimized the basic operating condition (mainly on washing solution concentration, cut-off size, and mixing ratio) to improve efficiently and economically the field-scale sequential soil washing process. The resulting optimized conditions were that solution concentration is 0.2M HCl, 1.0M HCl, 1.0M NaOH, that the cut-off size is 0.15mm (seive $\sharp$100), and that the mixing ratio is 1 3. Also, the optimized pH value for soil washing effluent treatment was 6 (33 ppb), in which the precipitation disruption caused by supersaturation of the floe did not occur. Results of TCLP tests showed that arsenic concentration from the washed gravels was 1.043 mg/L, that from soils ND (not detected), and that from filter cakes 0.066 mg/L. Also, the water content as a percentage of dewatered sludges was low $(48\%)$ and so the dewatered sludges can be disposed by landfilling. Through these results, we can concluded that tile field-scale sequential soil washing process developed in this study is adopted for remediation of arsenic-contaminated soils.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.1
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• pp.125-131
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• 2001

In this study, we compared the properties of 23 high and 55 low price sunglass lenses with the standards in the ordinary optical properties, materials, coloration, UV, IR and luminous transmittance, color acceptance for traffic signal, chromaticity and contrast sensitivity. The ordinary optical properties of the lenses met comparatively the requirements of the KS standard. The HIGH-type and LOW-type lenses were primarily made by glass and acrylate, respectively. In the coloration, HIGH-type was in group around neutral color but LOW-type was distributed widely on the line between 570 nm and 485 nm. There are fails in 7% of HIGH-type and 18% of LOW-type in the stimulus purity of the luminous transmittance. Wavelength of the UV/VIS cut-off was over 350 nm for HIGH-type but 6% of LOW-type was under 350 nm. In the erythemal UV, all HIGH-type met the needs of standards but 5 LOW-type failed with DIN standard In the near UV, KS standard worked in stringency, and HIGH-type showed more failure than LOW-type. The characteristics of the IR transmittance of HIGH-type was better than that of LOW-type. In the color acceptance of traffic signal, all HIGH-type met the needs of ANSI standards but 21.8% of LOW-type failed with the standard. In the contrast sensitivity tested with various coloured sunglasses, the value increased with increasing of Land decreasing of test distance. In view of the results so far, HIGH-type met with excellent properties as compared with LOW-type.

• Journal of Biomedical Engineering Research
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• v.14 no.3
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• pp.221-226
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• 1993

Modules of hemodiafilter were manufactured by using MC-Hp200 and RC-HP4DOA hoi low fiber membranes of Enka Co. in a unique design. The performances of she hemodiafillers were evaluated by measuring the molecular weight cut-off, ultrafiltration rate, clearance, and pressure drop across the hemodiafiter. As a whole, the performances of the RC-HP400A module were superior to those of the MC-Hp200 module. The modules prepared in thls study showed the satisfactory performances for hemodiafiltration.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1887-1891
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• 2008

In this paper, we dealt with a partial discharge (PD) measurement method that has been accepted as an effective and non-destructive technique to estimate insulation performance of low-voltage induction motors. The PD measurement system consists of a coupling network, a low noise amplifier, and associated electronics. A shielded box was used to reduce environmental noise. Frequency characteristic of the coupling network was estimated by a sinusoidal signal input, and the low cut-off frequency of the coupling network was 1 MHz (-3 dB). Also, we carried out a calibration test for the PD measurement system. Sensitivity of the system was of 84 m$V_{max}$/pC between stator winding and enclosure. In application test on a low-voltage three phase induction motor (5 HP), we could detect 88 pC at AC 800 $V_{max}$.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.1
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• pp.33-38
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• 2012

An experimental study was carried out to observe the characteristics of impingement of assist gas from a rectangular supersonic nozzle on kerf surface in laser machining. A micro-scale supersonic (Mach number 2.0) rectangular nozzle system was designed and fabricated for the purposes, and hot tests of the performance of the nozzle system was proceeded in the ITI corporation laboratory. For various related parameters such as laser powers, nozzle pressures and cutting speeds, the quality of the frontal view of cut edge surfaces was observed by a microscope. In the study, it was shown that the application of the present micro-rectangular supersonic nozzle in an off-axis configuration made it possible to cut a mild steel, by combinations of relatively low laser - powers, large standoff distances, and assist gas with no oxygen, which was not achieved by conventional laser cutting processes.

• Journal of Sensor Science and Technology
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• v.29 no.3
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• pp.180-186
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• 2020

In this study, we applied edge-pulse modulation to prevent the flicker of light-emitting diode (LED) light in a visible light identification system. In the visible light transmitter, positive pulses were transmitted at the edges of the low-to-high transition points, and negative pulses were transmitted at the edges of the high-to-low transition points of the non-return-to-zero (NRZ) data waveforms. In the visible light receiver, the NRZ waveforms were regenerated by making low-to-high and high-to-low transitions at the point of the positive and negative pulses, respectively. This method has two advantages. First, it ensures that the LED light is flicker-free because the average optical power of the LED was kept constant during data transmission in the transmitter. Second, the 120 Hz optical noise from the adjacent lighting lamps was easily cut off using a simple RC-high pass filter in the receiver.

• Journal of the Korean Data and Information Science Society
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• v.17 no.2
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• pp.355-366
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• 2006

Customer Satisfaction (CS) in Auto insurance market is the important factor which makes customer loyalty and retention increase. Recently On-line companies are threatening the existing Off-line companies with taking advantage of the low price through cut-offing the price by internet marketing. Therefore, the CS is becoming an indispensable survival strategy to the Off-line companies. Under these circumstances, this study finds out what the CS factors are in the auto insurance market, and produces levels of CS, customer loyalty and satisfaction Index of each category. The purpose of this study is to suggest the strategic improvement factor for elevating CS level and strategic direction for CS management by CS portfolio analysis based on the survey result.

• Journal of Acupuncture Research
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• v.32 no.1
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• pp.109-118
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• 2015

Objectives : This study aimed to investigate the correlation between fear-avoidance beliefs and neck pain/neck disability caused by traffic accidents. Methods : We surveyed 52 patients who were injured in traffic accidents. The patients completed baseline measures of pain, disability, fear-avoidance beliefs according to the visual analogue scale(VAS), neck disability index(NDI) and a fear-avoidance beliefs questionnaire (FABQ). At the end of medical treatment, VAS and NDI were reassessed. In order to determine the relationship between FABQ(including its subscales), change of VAS and NDI, Pearson correlation coefficients were used. To examine the accuracy of previously reported cut-off scores, we classified the patients into low and high groups and analyzed the change of VAS and NDI. The relationship was measured by Mann-Whitney U-test and a student's T-test. Results : FABQ and its subscales(total, physical activity and work) were significantly correlated with final VAS and NDI. FABQ-T showed low significant negative correlation with change of NDI. Previously reported cut-off scores did not show a statistical significance in this study Conclusions : This study suggests that screening for fear-avoidance beliefs may be useful for identifying patients at risk of prolonged pain after traffic accidents.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.13 no.2
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• pp.190-199
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• 2006

Purpose: To provide basic data and to identify the risk of pressure ulcers among neurological patients in ICU. Method: The participants in the study were on 78 neurological patients in the ICU of 3 hospitals. Data were collected every other day from 24 hours after admission, for up to 40 days or until discharge. The total period of data collection was 3 months. The risk assessment scales used for pressure ulcer were the Cubbin & Jackson(1991) scale and the National Pressure Ulcer Advisory Panel(1989) skin assessment tool. Results: There was a significant relationship between having a pressure ulcers and weight, skin condition, mental status, respiration, hygiene and hemodynamic status compared to not having a pressure ulcer. The incidence rate of the pressure ulcer was 28.2%(n=22). Of these patients the mean number of hospitalization days until pressure ulcer development was 5.2 days. The most common pressure ulcer site was the coccyx(39.3%). Based on a cut-off point of 24, 9 patients with risk scores <24 on admission also showed risk score for development of pressure ulcers, 10 patients with pressure ulcer scores ${\geq}24$ were older, hospitalized for a longer time, had low serum albumin, low hemoglobin, diabetes mellitus and surgery. Conclusion: In order to make the Cubbin & Jackson risk assessment scales more useful, there is a need to determine the reliability of the upper cut-off point 24. The result also showed a need to assess other risk factors and for early identification of at-risk patients in order to provide preventive care from admission to discharge.