• Nuclear Engineering and Technology
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• 제53권2호
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• pp.484-497
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• 2021

This paper proposes an extended time uncertainty analysis approach in Level 2 human reliability analysis (HRA) considering severe accident management (SAM) strategies. The method is a time-based model that classifies two time distribution functions-time required and time available-to calculate human failure probabilities from delayed action when implementing SAM strategies. The time required function can be obtained by the combination of four time factors: 1) time for diagnosis and decision by the technical support center (TSC) for a given strategy, 2) time for strategy implementation mainly by the local emergency response organization (ERO), 3) time to verify the effectiveness of the strategy and 4) time for portable equipment transport and installation. This function can vary depending on the given scenario and includes a summation of lognormal distributions and a choice regarding shifting the distribution. The time available function can be obtained via thermal-hydraulic code simulation (MAAP 5.03). The proposed approach was applied to assess SAM strategies that use portable equipment and safety depressurization system valves in a total loss of component cooling water event that could cause reactor vessel failure. The results from the proposed method are more realistic (i.e., not conservative) than other existing methods in evaluating SAM strategies involving the use of portable equipment.

• 수산해양교육연구
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• 제28권5호
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• pp.1358-1364
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• 2016

Maritime accidents caused by a ship include collisions, sinking, stranding and fire etc. This study is intending to consider fire accidents among such diverse marine accidents. It is much likely that various sorts of fires break out because crewmen are living in a narrow space for long periods of time consequent on the ship's characteristic of sailing on the sea. According to the ship fire survey, about 50% of the total fire accidents occurred at an engine room, and the main fire origin was analyzed to be oil. In addition, ship fire breaks out in the order of baggage racks and living quarter. In short, the survey indicates that all sorts of fires belonging to A, B, C and D-class have occurred. This study, targeting an actual passenger ship 'A', found the response time to evacuation, during which the people on board a ship recognize the outbreak of fire, and act, and the travel time for evacuation which is the actual travel time. In addition, this study carried out a simulation through the special program for fire analysis - FDS (Fire Dynamics Simulator) in order to find the effective evacuation time, i.e. life survival time. Particularly, this study did comparative analysis of the influence on the survival of passengers and crew based on the collected simulation data by fire size and sort. As a result of the analysis, it was found that when examining the only actual evacuation movement time excepting the response time to evacuation, people are safe by completing evacuation before the effective evacuation time only in case fire size is 100Kw among all sorts of fires. In other words, in case of the outbreak of fire more than 1 MW, it was found to fail to meet evacuation safety regardless of fire size.

• 한국응용과학기술학회지
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• 제33권4호
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• pp.777-787
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• 2016

본 연구는 표면 반응 분석법을 이용하여 곤드레 데치기 최적 공정 조건을 확립하고 각각의 공정으로부터 생산된 곤드레 추출물로부터 총 페놀 화합물, 플라보노이드의 함량, DPPH 라디칼 소거능을 분석하였다. 최적 공정 확립을 위한 데치기 공정 범위로 온도는 $70^{\circ}C-99^{\circ}C$, 시간은 70 - 170 sec.로 하였다. 데치기 공정 후 총 페놀 함량의 범위는 13.00 - 35.48 mg/g 이고 최대 예측 총 페놀함량은 35.48 mg/g, 총 페놀 함량의 경향을 보면 데치기 온도에 따라 급격히 감소하다가 증가하는 것으로 보여 지므로 온도에 의해 더 많은 영향을 받는 것으로 나타난다. 플라보노이드의 함량의 범위는 2.31 - 8.38 mg/g 이고 최대 예측 플라보노이드 함량은 8.38 mg/g 이었다. 플라보노이드 함량의 경향을 보면 데치기 시간에 따라 서서히 증가하다가 급격히 감소하는 것으로 보여 지므로 시간에 의해 더 많은 영향을 받는 것으로 나타났다. DPPH 라디칼 소거능의 범위는 42.10 - 67.14%이고 최대 예측 DPPH 라디칼 소거능은 67.14%로 측정 되었다. DPPH의 경향을 보면 데치기 온도에 따라 증가하다가 급격히 감소하는 것으로 보여 지므로 온도에 의해 더 많은 영향을 받는 것으로 나타난다. 따라서 데치기 공정 최적조건은 온도 $85^{\circ}C$와 시간 150 sec. 로 결정되었다.

• Current Research on Agriculture and Life Sciences
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• 제28권
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• pp.53-62
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• 2010

원적외선 조사가 포도씨 기능성분의 변화에 미치는 영향을 알아보고자 가열출력(0, 900, 1800 W) 및 가열시간(0, 20, 40 min)을 달리하여 원적외선 조사 후 마이크로파를 이용하여 포도씨 추출물을 제조하고 기능성분으로서 가용성 고형분, 기계적 색도, 카테킨, 총 페놀, 총 플라보노이드 함량 및 전자공여능과 아질산염 소거능을 각각 측정하였다. 가용성 고형분 함량 및 백색도 및 적색도는 유의적인 차이가 없는 것으로 나타났다. Cathechin류는 가열시간에 따라 catechin, procyanidin $B_2$, epicatechin 함량의 변화가 있음을 확인하였으며, 총 catechin 함량은 총 카테킨 함량은 900 W 및 20분 처리 시 가장 높게 나타났다. 총 페놀성화합물 및 플라보노이드 함량 또한 가열출력 900W 및 가열시간 20분 일 때 가장 높게 나타났다. 그에 따라 전자공여능도 가열출력 900 W 및 가열시간 20분 일 때 가장 높은 것으로 나타났다. 이상의 결과는 원적외선 처리에 의해 총 페놀성 화합물 함량, 총 플라보노이드 함량이 증가됨을 볼 수 있었으며, 특히 cathechin류의 변화가 있음을 확인할 수 있었다. 또한 이로 인해 항산화능도 증가됨을 알 수 있었다. 또한 포도씨의 원적외선 가열처리 최적조건을 설정하고자 가열출력 및 가열시간을 달리하여 중심합성실험계획으로 반응표면분석한 결과 가열출력 621.82~818.18 W, 가열시간 16.3~19.83 min의 범위가 최적 가열조건범위로 설정되었다.

• 대한임상전기생리학회지
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• 제7권1호
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• pp.7-10
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• 2009

Purpose : The purpose of this study was to investigate the effect of electrical stimulation applied in dominant forearm on autonomic nervous system response of both hands. Methods : Fourteen healthy subjects (women) received low frequency-high intensity electrical stimulation to one forearm. The subjects assigned to two groups; a ipsilateral stimulation group (n=7) and a contralateral stimulation group (n=7). The electrode attachment was arranged on the forearm of the dominant arm and the electricity stimulus time was set as 15 minutes. Measuring items were the skin conduction velocity, the blood flow, and the pulse rate, which were measured total 3 times (pre, post, and post 10 min.). Results : The skin conduction velocity showed a significant difference according to the change of the time in both hands, but there was no significant difference according to time in the blood flow, and the change of the pulse frequency regardless of stimulus side. Conclusion : These results demonstrate that the low frequency-high intensity electrical stimulation applied dominant forearm can increase selectively only with the skin conduction velocity, which may be helpful for the activation of the sudomotor function of both hands by the activation of sympathetic nerve.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.955-959
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• 2003

A technique for realizing linear phase IIR filters has been proposed by Powell-Chau which gives a real-time implementation of H(z-1).H(z), where H(z) is a causal nonlinear phase IIR filter. Powell-Chau system is linear but not timeinvariant system. Therefore, that system has group delay response that exhibits a minor sinusoidal variation superimposed on a constant value. In the signal processing, this oscillation seriously degrade the signal quality. Unfortunately, that system has a large sample delay of 4L and also more computational complexity. Proposed system is present a reduced computational complexity technique by moved the numerator polynomial of H(1/z) out to cascade with causal filter H(z) and remain only all-pole of H(1/z), then applied truncated infinite impulse response to finite with truncated IIR filtel $H_L$(z) and L sample delay to subtract the output sequence from the top and bottom filter. Proposed system is linear time invariance and group delay response and total harmonic distortion are also improved.

• Journal of Biosystems Engineering
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• 제36권6호
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• pp.476-483
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• 2011

The aerial application using an unmanned helicopter has been already utilized and an attitude controller would be developed to enhance the operational convenience and safety of the operator. For a preliminary study of designing flight controller, a state space model for an RC helicopter would be identified. Frequency sweep flight tests were performed and time history data were acquired in the previous study. In this study, frequency response of the flight test data of a small unmanned helicopter was analyzed by using the CIFER software. The time history flight data consisted of three replications each for collective pitch, aileron, elevator and rudder sweep inputs. A total of 36 frequency responses were obtained for the four control stick inputs and nine outputs including linear velocities and accelerations and angular velocities in 3-axis. The results showed coherence values higher than 0.6 for every primary control inputs and corresponding on-axis outputs for the frequency range from 0.07 to 4 Hz. Also the analysis of conditioned frequency response showed its effectiveness in evaluating cross coupling effects. Based on the results, the dynamic characteristics of the model helicopter can further be analyzed in terms of transfer functions and the undamped natural frequency and damping ratio of each critical mode.

• Journal of Applied Biological Chemistry
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• 제58권2호
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• pp.117-124
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• 2015

The extract of white rose petals has an antioxidant effect and can be used to treat allergic disease. The purpose of this study was to identify optimal conditions for extracting antioxidative compounds from white rose petals with 2,2-diphenyl-1-picrylhydrazyl scavenging activities. A response surface methodology based on a central composite design was used to investigate the effects of three independent variables: ethanol concentration ($X_1$), extraction temperature ($X_2$), and extraction time ($X_3$). The estimated optimal conditions for obtaining phenolic compounds with antioxidant activities were as follows: ethanol concentration of 42% ($X_1$), extraction time of 80 min ($X_3$), and extraction temperature of $75^{\circ}C$ ($X_2$). The estimated optimal conditions for obtaining flavonoid compounds with antioxidant effects were an ethanol concentration of 41% ($X_1$), extraction time of 119 min ($X_3$), and an extraction temperature of $75^{\circ}C$ ($X_2$). Under these conditions, predicted response values for the phenolic and flavonoid contents were 243.5 mg gallic acid equivalent/g dry mass and 19.93 mg catechin equivalent (CE)/g dry mass, respectively.

• 한국식품과학회지
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• 제41권3호
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• pp.245-250
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• 2009

사과 pomace의 알콜 추출 조건을 최적화하기 위하여 중심합성계획법을 이용하여 용매비와 침지시간, 추출시간, 추출온도는 독립변수로 수율과 총 폴리페놀 함량은 종속변수로 설정하였다. 실험 결과 최적조건은 반응표면분석을 이용하여 모니터링하였다. 반응표면그래프 분석 결과 사과 pomace의 알콜 추출 시 수율은 침지시간과 추출시간에는 큰 영향을 받지 않았으며, 시료에 대한 용매비가 높을수록 또는 추출온도가 높아질수록 증가하였다. 총폴리페놀 함량은 모든 독립변수에 영향을 받아 비례적으로 함께 증가하였으나 최고점을 보인 후 다시 감소되는 경향을 나타내었다. 총 폴리페놀 함량을 최대로 하는 최적 알콜 추출 조건은 사과 pomace에 용매비를 13.00 mL/g로 하고 89.02분 동안 침지시킨 후 $70^{\circ}C$에서 180분 추출하였을 때로서 그 때의 수율은 3.76%, 총 폴리페놀 함량은 29.68 mg catechin equiv./g으로 나타났다.

• 한국물환경학회지
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• 제30권3호
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• pp.304-310
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• 2014

The conventional methods for total residual chlorine such as iodometry and DPD colorimetric can cause secondary pollution due to additional agents, also have a wide error range. As for alternative, electrochemical method can measure TRC(Total residual chlorine), and is not required as additional agents, also very suitable for using the fields of ballast water because test time is relatively fast. Therefore, this study was investigated for changing charge by agitation, salt concentration, and temperature change. Charge showed differences based on changes of reduction peak with or without agitation. In contrast, TRC and charge were well correlated in constant agitation speed. As TRC and charge were analyzed with high correlations in constant salinity and temperature of ocean, thereby conductivity was firstly measured, and charge had high correlation for TRC in spite of changing salinity and temperature Pt electrode revealed high reliability ($r^2=0.960$) because it was rarely effected by TRC, On the other hand, Au electrode appeared inadequate ($r^2=0.767$) to use sensor in less than 1.0 ppm of TRC. For high accuracy and detection of TRC, Pt and Au electrodes for test time were, respectively, 14 and 22 seconds. As a result, Pt electrode was more valuable than Au electrode in terms of response time.