• 제목/요약/키워드: cut off level

검색결과 309건 처리시간 0.024초

중성선 선로 전압강하를 이용한 단락사고 방지용 보호장치 개발 (Development of Prevention Apparatus for Short-Circuit Faults Using the Line Voltage Drop of Neutral Wire)

  • 곽동걸;김진환;이봉섭
    • 전기학회논문지
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    • 제61권12호
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    • pp.1953-1958
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    • 2012
  • 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 such electric faults, specially short circuit faults. Earth Leakage Circuit Breaker (ELB) and Molded_case Circuit Breaker (MCCB), that is, Residual Current Protective Devices (RCDs) used on low voltage distribution lines cut off earth leakage and overload, but the RCD can not cut off electric arc or spark to be a major factor of electrical fire. As the RCDs which are applied in low voltage distribution panel are prescribed to rated breaking time about 30ms(KS C 4613), the RCDs can't perceive to the periodic electric arc or spark of more short wavelength level. To improve such problem, this paper proposes a prevention apparatus using the line voltage drop of neutral wire and some semiconductor switching devices. Some experimental tests of the proposed apparatus confirm the validity of the analytical results.

아크사고 발생 시 전압 왜형파를 이용한 아크차단기 개발 (Development of Arc Fault Circuit Interrupter Using the Distorted Voltage Wave in Electric Arc Faults)

  • 곽동걸
    • 전기학회논문지
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    • 제62권6호
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    • pp.876-880
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    • 2013
  • The major causes of electrical fire are classified to short circuit fault, overload fault, electric leakage and electric contact failure. The principal factor of the fire is electric arc or spark accompanied with such electric faults. Earth Leakage Circuit Breaker (ELB) and Molded_case Circuit Breaker (MCCB), that is, Residual Current Protective Devices (RCDs) used on low voltage distribution lines cut off earth leakage and overload, but the RCD can not cut off electric arc or spark to be a major factor of electrical fire. As the RCDs which are applied in 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 improve such problems, this paper studies on an arc fault circuit interrupter (AFCI) using the distorted voltage wave in electric arc faults. The proposed voltage sensing type AFCI is an electrical fire prevention apparatus of new conception that operates a circuit breaker with sensing the instantaneous voltage drop of line voltage at electrical faults occurrence. The proposed AFCI is composed of control circuit topology using some semiconductor switching devices. Some experimental tests of the proposed AFCI confirm practicality and the validity of the analytical results.

Classification-Based Approach for Hybridizing Statistical and Rule-Based Machine Translation

  • Park, Eun-Jin;Kwon, Oh-Woog;Kim, Kangil;Kim, Young-Kil
    • ETRI Journal
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    • 제37권3호
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    • pp.541-550
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    • 2015
  • In this paper, we propose a classification-based approach for hybridizing statistical machine translation and rulebased machine translation. Both the training dataset used in the learning of our proposed classifier and our feature extraction method affect the hybridization quality. To create one such training dataset, a previous approach used auto-evaluation metrics to determine from a set of component machine translation (MT) systems which gave the more accurate translation (by a comparative method). Once this had been determined, the most accurate translation was then labelled in such a way so as to indicate the MT system from which it came. In this previous approach, when the metric evaluation scores were low, there existed a high level of uncertainty as to which of the component MT systems was actually producing the better translation. To relax such uncertainty or error in classification, we propose an alternative approach to such labeling; that is, a cut-off method. In our experiments, using the aforementioned cut-off method in our proposed classifier, we managed to achieve a translation accuracy of 81.5% - a 5.0% improvement over existing methods.

국내 연구용원자로 전출력 내부사건 1단계 확률론적안전성평가 (Internal Event Level 1 Probabilistic Safety Assessment for Korea Research Reactor)

  • 이윤환;장승철
    • 한국안전학회지
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    • 제36권3호
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    • pp.66-73
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    • 2021
  • This report documents the results of an at-power internal events Level 1 Probabilistic Safety Assessment (PSA) for a Korea research reactor (KRR). The aim of the study is to determine the accident sequences, construct an internal level 1 PSA model, and estimate the core damage frequency (CDF). The accident quantification is performed using the AIMS-PSA software version 1.2c along with a fault tree reliability evaluation expert (FTREX) quantification engine. The KRR PSA model is quantified using a cut-off value of 1.0E-15/yr to eliminate the non-effective minimal cut sets (MCSs). The final result indicates a point estimate of 4.55E-06/yr for the overall CDF attributable to internal initiating events in the core damage state for the KRR. Loss of Electric Power (LOEP) is the predominant contributor to the total CDF via a single initiating event (3.68E-6/yr), providing 80.9% of the CDF. The second largest contributor is the beam tube loss of coolant accident (LOCA), which accounts for 9.9% (4.49E-07/yr) of the CDF.

의약품 허가외사용 관리 체계 발전 방안 (Development of Regulation System for Off-Label Drug Use)

  • 이인향;서미경;이영숙;계승희;김현아;이숙향
    • 약학회지
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    • 제58권2호
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    • pp.112-124
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    • 2014
  • This study aimed to develop a regulation system for off-label drug use to secure the safe use of marketed drugs. We searched governmental documents for national and global regulating systems of off-label drug uses and a body of academic literature to explore current regulating trends. We included European Union, United Kingdom, United States of America, Australia and Japan, and critically reviewed the regulation of off-label drug use in four issues, which were a regulatory structure, safety control before and after off-label use, and information management. The findings of the present investigation called for several measures in off-label drug uses: enhancing prescribers' self-regulation, providing up-to-date information to prescribers for evidence-based practice and to patients for their informed consent, making evidence with scientific rigor, building an official registering process for off-label use in good quality and extending the role of pharmaceutical industry in pharmacovigilance. At last, we proposed a new system so as to regulate and evaluate off-label drug uses both at national and institutional level. In the new system, we suggested a clear-cut definition for clinical evidence that applicants would submit. We newly introduced an official 'Off-Label Drug Use Report' to evaluate the safety and clinical efficacy of a given off-label drug use. In addition, we developed an algorism of the regulation of off-label drug use within an institution to help set up the culture of evidence-based practices in off-label drug uses.

적응필터 알고리즘을 이용한 스피커의 왜곡율 측정 (Measurement of Distortion Level of Loudspeaker using Adaptive Filter Algorithm)

  • 김천덕;지석근
    • 수산해양기술연구
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    • 제30권2호
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    • pp.125-131
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    • 1994
  • This paper describes a method to measure the distortion level of loudspeaker using a LMS(Least Mean Square) adaptive filter. Conventional technique to measure the distortion level uses a band-pass filter with a sharp cut-off frequency characteristics. However. such the band-pass filter has a bed time response characteristics. On the other hand, the proposed method offers us an easy way to measure the specified harmonic distortion level with a small hardware. Moreover, our method is not affected by noise which has no correlation with the test signal, and the measurement can be carried out in a noisy environment. The effectiveness of the proposed method is confirmed by experiment using a loudspeaker in a noisy room.

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CA저장 사과를 이용한 Fresh-cut Apple의 제조 및 MAP저장 (Processing and MAP(modified atmosphere packaging) Storage of Fresh-cut Apples using CA Stored Apples)

  • 정헌식;문광덕;최종욱
    • 한국식품저장유통학회지
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    • 제6권4호
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    • pp.351-356
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    • 1999
  • CA 저장 사과로 제조한 신선절단 사과의 비타민 C 강화와 품질유지기간을 연장하기 위한 방법을 개발하기 위한 일환으로 신선절단 사과를 10% L-ascorbic acid 용액에 침지처리하고 0.03 mm LDPE, 0.04 mm PP 및 0.08 mm Nylon/PE(질소치환) 필름으로 포장하여 1$0^{\circ}C$에서 저장하면서 포장내 기체농도와 품질변화를 조사하였다. 저장 중 포장내 산소는 Nylon/PE 포장구에서 가장 낮게 l~3%로 유지되었고 다음으로 PP, LDPE 포장구 순이었다. 저장초기 포장내 에틸렌 농도의 증가속도는 Nylon/PE 포장구에서 가장 낮았다. 신선절단 사과의 비타민 C 함량은 241mg/100g으로 강화되었으며, 저장 중에는 저산소 조성 포장조건일수록 ascorbic acid 산화를 억제시켜서 Nylon/PE 포장구에서 가장 높게 유지되었다. 절단사과에서 갈변은 저산소 조성 포장조건일수록 억제하는 경향이었으며 LDPE, PP 및 무포장 절단사과는 저장 6일 후부터 발생되었으나 Nylon/PE 포장 절단사과는 저장 14일 후까지도 발생되지 않았다. 절단사과에서 부패와 이취는 LDPE, PP 및 무포장에서는 저장 9일 후에 인지되었으나 Nylon/PE 포장에서는 저장 14일 후까지도 인지되지 않았다. 이상의 결과에서 볼 때 장기간 CA 저장한 사과로 비타민 C 함량이 강화된 신선절단 사과의 제조가 가능하였고 이의 품질유지에 적합한 포장조건은 산소투과도가 낮은 포장재와 산소 제거 후 밀봉하는 것으로 나타났다.

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화학반응기의 안전성 향상을 위한 예방조치 개선에 관한 연구 (A Study on the Improvement of Preventive Measures for Improving the Safety of Chemical Reactor)

  • 변윤섭
    • 한국가스학회지
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    • 제24권4호
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    • pp.32-38
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    • 2020
  • 화학반응기에 발생한 화재·폭발 사고사례를 기반으로 화학반응기에 설치되어 있는 예방조치의 문제점을 분석하였다. 화학반응기는 다품종의 화학제품을 생산하며, 반응폭주시 급격히 상승하는 압력을 해소하기 위해 파열판을 설치하고 파열판의 기능을 유지하기 위해 배출물질을 대기로 배출하도록 허용하고 있어 화재·폭발사고가 발생하였다. 이를 개선하기 위한 방안으로 안전건전성수준(SIL3)을 기반으로 한 안전계장시스템(SIS)을 화학반응기의 예방조치로 적용하였다. 화학반응기의 원재료를 적하하는 배관에 긴급차단밸브를 직렬로 2개 설치하여 반응폭주시 긴급차단밸브 2개 중 1개만 작동하여도 원재료 공급을 차단할 수 있도록 하고, 반응응제제 공급배관에는 자동 ON/OFF 밸브를 병렬로 설치하여 반응폭주시 1개의 밸브만 열려도 반응억제제가 투입될 수 있게 하였다.

어린이 영양지수(NQ-C)를 이용한 중국 일부 어린이의 식행동 실태 평가 (Assessment of dietary behavior of Chinese children using nutrition quotient for children)

  • 황예순;김혜영
    • Journal of Nutrition and Health
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    • 제47권5호
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    • pp.342-350
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    • 2014
  • 본 연구는 한국영양학회 한국암웨이에서 2012년에 개발한 어린이 영양지수 (NQ-C, Nutrition Quotient for Children) 설문지를 이용하여 중국 산동성과 강수성 지역 초등학교 5, 6학년어린이 336명 (남학생: 166명, 여학생: 170명)의 식 행동을 살펴보고자 수행하였고, 그 결과를 요약하면 다음과 같다.1) 어린이의 평균 영양 지수 (NQ) 점수는 백점 만점에 69.5점으로 양호한 수준이었고, 성별에 따른 차이는 없었다. 개별영역별로는 균형점수 58.8점, 절제점수 84.9점, 다양점수 63.6점, 규칙점수 76.1점, 실천점수 73.6점으로 나타났다. 영역별 진단기준치와 비교해볼 때, 어린이들의 평균균형, 절제, 규칙, 실천 점수는 기준치에 비해 양호한 편이었으나, 다양 점수는 진단기준치에 미치지 못하였다. 2) 어린이 영양지수의 최상위 등급은 13.7%, 상위등급은 23.5%, 중위 등급은 50.3%, 하위는 9.5%, 최하위 등급은 3.0%로 나타나서 최상위와 상위 등급의 비율이 기대치인 10%와 15%를 넘었고, 반면 하위와 최하위 등급의 비율은 기대치보다 더 적어서 바람직한 모습을 보였으며, 남녀 간의 유의차는 없었다. 3) 아버지의 학력은 어린이의 균형 점수, 규칙 점수와 상관성이 있었고, NQ 점수와도 유의적인 양의 상관관계를 보였다. 어머니의 학력도 아버지와 비슷하게 균형 점수, 규칙 점수와 양의 상관관계를 보였고, 어머니가 취업을 한 경우 어린이의 규칙점수가 더 높은 것으로 나타났다. 4) 조사대상자의 1일 운동 시간이 증가할수록 NQ 점수가 유의적으로 높았고, 하루에 1시간 이상 운동을 하는 학생들은 운동을 하지 않는 학생들보다 균형, 다양, 규칙, 실천 영역의 점수가 유의적으로 높았다. 본 연구의 결과를 종합해 볼 때, 중국 중소도시 어린이의 영양지수 평균 점수는 69.5점으로 양호하였고, 균형, 절제, 규칙, 실천 점수는 양호하지만, 다양성 점수는 개선이 필요한 것으로 나타났다. 한국에서 개발된 어린이 영양지수(NQ-C) 설문지는 비슷한 생활 패턴을 가진 중국 초등학생 의 식행동 실태 평가에 활용이 가능한 것으로 사료되며, 조사대상 지역에 따라 영양지수 점수와 영역별 점수가 다르게 나타나므로, NQ-C를 활용한 영양상태 평가 후에 각 지역에 맞는 영양교육 프로그램을 개발하는 것이 필요하다고 사료된다.

개정된 가이드라인에 따른 아세트아미노펜 급성 중독환자 치료 기준의 검증 (Evaluation of Cut-off Values in Acute Acetaminophen Intoxication Following the Revised Guideline of the United Kingdom)

  • 박성진;차경만;소병학;김형민;정원중
    • 대한임상독성학회지
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    • 제16권2호
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    • pp.68-74
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    • 2018
  • Purpose: In 2012, a revised guideline for acute acetaminophen overdose was proposed in the UK, recommending that the treatment threshold should be lowered to 100 mcg/ml at 4 hours after ingestion without risk stratification of hepatotoxicity. However, the poison centers in some developing countries do not have laboratory resources to provide serum drug levels in time. The primary aim of the study is to evaluate the cut-off value of reported dose per kilogram to determine when N-acetylcysteine treatment is warranted under the revised guideline. Methods: Data were collected retrospectively from the toxicology registry of an urban emergency medical center between 1st January 2010 and 30th June 2017. Inclusion criteria were single acute overdose of more than 75 mg/kg in 15 hours from ingestion and over 14 years of age. Subgroups were created by 25 mg/kg increments of reported dose, then sensitivity, specificity, positive predictive value and negative predictive value were calculated for the cut-off values of 100 mg/kg, 125 mg/kg, 150 mg/kg and 175 mg/kg for toxic serum level over '100-treatment line'. Results: A total of 99 patients were enrolled in the study; 24 patients showed toxic serum levels (24.2%). Zero of 17 patients with an ingestion dose under 100 mg/kg showed toxic level (0%), and 0 of 15 under 125 mg/kg (0%), 2 of 14 under 150 mg/kg (14.3%), and 4 of 12 under 175 mg/kg (33.3%) had toxic levels. The higher the ingested dose per kilogram of weight, the higher the frequency of the toxic serum concentration on the first test (${\chi}^2$ test for trend, ${\chi}^2=22.66$, p-value<0.001) and the sensitivity of each value was 100%, 100%, 92% and 76%. Conclusion: In acute single acetaminophen intoxication, the ingestion dose of 100 mg/kg of weight will be useful in determining the need for the N-acetylcysteine antidote in the indigent laboratory environment.