• 한국환경과학회지
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• 제26권2호
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• pp.221-230
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• 2017

To determine the effect of air pollution reduction policies, the long-term trend of air pollutants should be analyzed. Kolmogorov-Zurbenko (KZ) filter is a low-pass filter, produced through repeated iterations of a moving average to separate each variable into its temporal components. The moving average for a KZ(m, p) filter is calculated by a filter with window length m and p iterations. The output of the first pass subsequently becomes the input for the next pass. Adjusting the window length and the number of iterations makes it possible to control the filtering of different scales of motion. To break down the daily mean $PM_{10}$ into individual time components, we assume that the original time series comprises of a long-term trend, seasonal variation, and a short-term component. The short-term component is attributable to weather and short-term fluctuations in precursor emissions, while the seasonal component is a result of changes in the solar angle. The long-term trend results from changes in overall emissions, pollutant transport, climate, policy and/or economics. The long-term trend of the daily mean $PM_{10}$ decreased sharply from $59.6ug/m^3$ in 2002 to $44.6ug/m^3$ in 2015. This suggests that there was a long-term downward trend since 2005. The difference between the unadjusted and meteorologically adjusted long-term $PM_{10}$ is small. Therefore, we can conclude that $PM_{10}$ is unaffected by the meteorological variables (total insolation, daily mean temperature, daily mean relative humidity, daily mean wind speed, and daily mean local atmospheric pressure) in Busan.

• 한국ITS학회:학술대회논문집
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• 한국ITS학회 2003년도 제2회 정기총회 및 추계학술대회
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• pp.35-39
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• 2003

• 대한치주과학회:학술대회논문집
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• 대한치주과학회 1998년도 제38회 종합학술대회 연제초록
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• pp.112-113
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• 1998

• 한국운동역학회지
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• 제27권2호
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• pp.83-90
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• 2017

Objective: To investigate the effect of short-term vibration frequencies on muscle force generation capabilities. Method: Six healthy participants were recruited for this study and only their dominant leg was tested. The subjects were tested under five conditions of vibration frequencies with constant amplitude: 0 Hz (no vibration), 30 Hz, 60 Hz, and 90 Hz, and the vibration amplitude was 10 mm for all frequency conditions. The vibration was applied to the rectus femoris (RF). The subjects were then instructed to maintain a steady-state isometric knee joint torque (100 Nm) for the first 6 s. After the steady-state torque production, the subjects were required to produce isometric knee joint torque by leg extension as hard as possible with a start signal within the next 3 s. The vibration was applied for ~4 s starting from 1 s before initiation of the change in the steady-state knee joint torque. Results: The results showed that the maximum voluntary torque (MVT) of the knee joint increased with the vibration frequencies. On average, the MVTs were 756.47 Nm for 0 Hz (no vibration) and 809.61 Nm for 90 Hz. There was a significant positive correlation (r = 0.71) between the MVTs and integrated electromyograms (iEMGs). Further, the co-contraction indices (CCIs) were computed, which represent the ratio of the iEMGs of the antagonist muscle to the iEMGs of all involved muscles. There was a significant negative correlation (r = 0.62) between the CCIs and MVTs, which was accompanied by a significant positive correlation (r = 0.69) between the iEMGs of the vibrated muscle (RF). There was no significant correlation between the MVTs and iEMGs of the antagonist muscle. Conclusion: The results of this study suggest that the short-term vibration on the muscle increases the level of muscle activation possibly owing to the increased Ia afferent activities, which enhances the muscle force generation capability.

• 한국환경농학회지
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• 제21권1호
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• pp.69-73
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• 2002

질산태 질소의 일중 농도 변화와 단기간의 저온 처리가 질산태 질소의 흡수 및 농도에 미치는 영향을 살펴보고자 상추 (Lactuca sativa L.)를 공시 작물로 하여 온실에서 수경 재배하였다. 질산태 질소의 농도는 엽신에 비하여 주맥에서 일중 지속적으로 2배 이상 높았으며, 질산태 질소의 일중 변화는 14:00까지 지속적으로 감소하여 최저치 (8.7 mg-N/GDW)를 나타낸 후 다시 증가하였다. 질산태 질소의 일중 흡수량은 11:00$\sim$17:00에 평균 4.8 mg-N/GDW-Root/hr로 최대치를 나타내었다. 단기간의 저온 처리는 엽의 질산태 질소의 농도를 14$\sim$18%, 질산태 질소의 흡수량을 50$\sim$55%를 감소시켰다. 이러한 결과는 수확 전 단기간의 저온처리가 상추 잎의 질산태 질소함량을 낮출 수 있는 방법으로 응용될 수 있음을 보여준다.

• 운동영양학회지
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• 제24권1호
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• pp.29-36
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• 2020

[Purpose] The purpose of this study was to investigate the effects of short-term creatine intake on muscle fatigue induced by resistance exercise in healthy adolescent men, i.e., lactic acid concentration and wrist and head tremor measured by an accelerometer. [Methods] Twelve healthy adolescent men who had no experience with creatine intake were included. The subjects were randomly assigned to the creatine group and the placebo group, followed by 5 days of creatine and placebo intake, and 5 times of 5 sets of leg press, leg extension, bench press, and arm curl exercises at 70% repetition maximum (RM). The lactic acid concentration before and after exercising, rate of perceived exertion (RPE), and accelerometer-based wrist tremor and head tremor during exercise were measured. Subsequently, after 7 days to allow for creatine washout, the same exercise treatment and measurement were performed in each group after switching drug and placebo between the groups. [Results] The level of lactic acid before and after the acute resistance exercise trial was significantly lower in the creatine group than in the placebo group (P <0.05). The mean RPE during the resistance exercise was significantly lower in the creatine group than in the placebo group (P <0.05). There was no difference between the two groups in the mean wrist tremor during resistance exercise, but the mean head tremor values were significantly lower in the creatine group than in the placebo group in the arm curl, the last event of the exercise trials (P <0.05). [Conclusion] Short-term creatine intake reduces the blood fatigue factor increased by resistance exercise, and is thought to suppress fatigue, especially in the latter half of resistance exercise. Therefore, these findings indicate that short-term creatine intake can have an improved effect on anaerobic exercise performance.

• Clinical and Experimental Pediatrics
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• 제63권2호
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• pp.56-62
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• 2020

Background: Red blood cell (RBC) transfusion improves cardiorespiratory status of preterm infants by increasing circulating hemoglobin, improving tissue oxygenation, and reducing cardiac output. However, RBC transfusion itself has also been suggested to negatively affect short-term outcomes such as intraventricular hemorrhage (IVH), bronchopulmonary dysplasia (BPD), retinopathy of prematurity (ROP), and necrotizing enterocolitis (NEC) in premature infants. Purpose: This study aimed to analyze the relationship between RBC transfusion and short-term outcomes in very low birth weight (VLBW) infants (birth weight, <1,500 g). Methods: We retrospectively reviewed the medical records of VLBW infants admitted to the Soonchunhyang University Bucheon Hospital between October 2010 and December 2017. Infants who died during hospitalization were excluded. The infants were divided into 2 groups according to RBC transfusion status. We investigated the relationship between RBC transfusion and short-term outcomes including BPD, ROP, NEC, and IVH. Results: Of the 250 enrolled VLBW infants, 109 (43.6%) underwent transfusion. Univariate analysis revealed that all short-term outcomes except early-onset sepsis and patent ductus arteriosus were associated with RBC transfusion. In multivariate analysis adjusted for gestational age, birth weight and Apgar score at 1 minute, RBC transfusion was significantly correlated with BPD (odds ratio [OR], 5.42; P<0.001) and NEC (OR, 3.40; P= 0.009). Conclusion: RBC transfusion is significantly associated with adverse clinical outcomes such as NEC and BPD in VLBW infants. Careful consideration of the patient's clinical condition and appropriate guidelines is required before administration of RBC transfusions.

• 한국융합학회논문지
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• 제6권2호
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• pp.1-11
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• 2015

본 연구의 목적은 상징적 상호작용론적 견해에 바탕을 둔 근거이론 방법을 이용하여 간호대학생의 전공 융합한 해외 단기연수 경험에 대한 실체이론을 도출하고, 해외 단기연수가 나아가야 할 방향을 조명하는데 있다. 연구결과를 보면 참여자들은 연수 후 경험으로 내 안의 또 다른 '나'를 발견하고 더 넓은 세상으로 나가고자 하는 열망이 강하게 생기면서 삶에 대한 태도를 변화하기 시작하였고 이는 자아성숙으로 나타났다. 그러나 일부 참여자는 현실에 짓눌려 열망을 내려놓고 예전 삶으로의 회귀를 나타내기도 하였다. 본 연구결과를 토대로 볼 때, 전공 융합한 해외 단기연수 후에는 반드시 추후 프로그램을 운영하여 긍정적으로 변화된 열망, 동기, 자신감 등을 강화 유지시켜 주는 것이 필요하고, 개인 성향에 따른 맞춤형 추후 프로그램을 운영하는 것이 요구된다. 또한 추후 프로그램 운영 시 연수에 참여한 학생들에 대한 주기적인 평가를 통해 추후 시점마다 심리적 또는 교육적 지지자원을 분배 투입하는 것이 필요하다.

• KDI Journal of Economic Policy
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• 제31권2호
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• pp.15-45
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• 2009

본고에서는 3요인 무재정거래(3-factor no arbitrage) 조건하에서의 이자율 기간 구조를 추정하고 이를 이용하여 기간프리미엄의 추이 및 정책금리 변경의 유효성을 분석하였다. 기간프리미엄의 경우 3년물에서 높게 나타나고 있는데, 이는 장기적인 경제 상황보다 향후 3년 정도의 시계에서 경제의 불확실성이 높을 것이라는 투자자들의 인식을 반영한 것으로 해석된다. 한편, 최근 기준 지표금리의 변경에 따른 통화정책의 효과성을 살펴보기 위해 지표금리 변경시점을 전후로 하여 금융시장에서의 단기금리 변경이 채권시장의 수익률곡선의 형태에 미치는 효과를 분석해 보았다. 분석 결과, 금융시장에서의 대표적인 단기금리인 콜금리와 채권시장에서의 단기금리인 초단기이자율 간의 괴리가 지표금리 변경 이전과 비교하여 크게 확대된 점을 발견할 수 있었다. 이러한 괴리 확대가 새로운 기준금리에 대한 운용겸험 미숙에 연유한 것인지, 최근의 국제금융시장 불안에 따른 예외적인 경우인지는 현 단계에서는 명확히 결론짓기 어려우나 통화정책의 유효성을 제고하기 위해서는 이러한 괴리를 축소하는 통화정책 운용이 필요할 것이다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2021년도 학술발표회
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• pp.133-133
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• 2021

The performance of radar Quantitative Precipitation Estimation (QPE) using Long Short-Term Memory (LSTM) networks in hydrological applications depends on either the quality of data or the three-dimensional CAPPI structure from the weather radar. While radar data quality is controlled and enhanced by the more and more modern radar systems, the effect of CAPPI structure still has not yet fully investigated. In this study, three typical and important types of CAPPI structure including inverse-pyramid, cubic of grids 3x3, cubic of grids 4x4 are investigated to evaluate the effect of CAPPI structures on the performance of radar QPE using LSTM networks. The investigation results figure out that the cubic of grids 4x4 of CAPPI structure shows the best performance in rainfall estimation using the LSTM networks approach. This study give us the precious experiences in radar QPE works applying LSTM networks approach in particular and deep-learning approach in general.