• Journal of the Korean Society for information Management
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• v.32 no.2
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• pp.7-23
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• 2015

While there are several measures for node centralities, such as betweenness and degree, few centrality measures for local centralities in weighted networks have been suggested. This study developed a generalized centrality measure for calculating local centralities in weighted networks. Neighbor centrality, which was suggested in this study, is the generalization of the degree centrality for binary networks and the nearest neighbor centrality for weighted networks with the parameter ${\alpha}$. The characteristics of suggested measure and the proper value of parameter ${\alpha}$ are investigated with 6 real network datasets and the results are reported.

• Journal of the Korean Chemical Society
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• v.37 no.12
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• pp.1025-1034
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• 1993

We have measured ${\pi}^*$, $\alpha$ and $\beta$ polarity parameters of 2-propanol / hexane and ethyl acetate / hexane mixed solvents over the entire range of composition. For the ethyl acetate / hexane system, only ${\pi}^*$ and $\beta$ were measured since $\alpha$ of these mixed solvents are defined zero. We have corrected the measured polarity parameters to obtain consistent data with the existing literature data assuming a good linear correlation between the measured and the true values. The variation patterns are consistent with the expected trends based on the chemistry of the solvent components. The general trends of the two solvent systems are summarized as follows. ${\pi}^*$ merely increases as the content of the more polar solvent increases while $\alpha$ and $\beta$ increase with the increase of the content of the more polar solvent, then decrease upon continuing addition of the more polar solvent.

• Journal of the Korea Convergence Society
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• v.10 no.4
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• pp.1-6
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• 2019

Neural networks have been used to predict the direction of stock index movement from past data. The conventional research that predicts the upward or downward movement of the stock index predicts a rise or fall even with small changes in the index. It is highly likely that losses will occur when trading ETFs by use of the prediction. In this paper, a neural network model that predicts the movement direction of the daily KOrea composite Stock Price Index (KOSPI) to reduce ETF trading losses and earn more than a certain amount per trading is presented. The proposed model has outputs that represent rising (change rate in index ${\geq}{\alpha}$), falling (change rate ${\leq}-{\alpha}$) and neutral ($-{\alpha}$ change rate < ${\alpha}$). If the forecast is rising, buy the Leveraged Exchange Traded Fund (ETF); if it is falling, buy the inverse ETF. The hit ratio (HR) of PNN1 implemented in this paper is 0.720 and 0.616 in the learning and the evaluation respectively. ETF trading yields a yield of 8.386 to 16.324 %. The proposed models show the better ETF trading success rate and yield than the neural network models predicting KOSPI.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.2
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• pp.137-143
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• 2008

Rapid canopy closure (RCC) is one of the physiological attributes that may enhance genetic yield potential of rice (Oryza sativa L.) in a growing season. Crop growth before canopy closure could be described by an exponential equation of $y\;=\;{\alpha}{\cdot}{\exp}({\beta}{\cdot}t)$ where $\alpha$ is the crop leaf area index (LAI) or shoot dry weight (DW), t is the thermal time, $\beta$ is the LAI or DW at the beginning of the exponential growth and is the relative growth rate of LAI ($m^2m^{-2}^{\circ}C^{-1}$) or DW($gg^{-2}^{\circ}C^{-1}$). Field experiment using 22 cultivars revealed that the exponential growth phase before canopy closure can be divided into two sections; an earlier section during which crop dry weight and LAI of varieties are highly dependent on $\alpha$ and a second section where crop dry weight and LAI are highly dependent on $\beta$. Grain weight had significantly positive correlation with $\alpha$ parameter and dry weight and LAI during early exponential phase. The parameter $\beta$ of the exponential growth curve had positive and significant correlation with the LAI and dry weight during the late exponential growth phase, grain number per unit area, and grain yield. There was genotypic difference for RCC parameters, $\alpha$ and $\beta$, indicating the possibility of genetic improvement for these traits.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.4
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• pp.381-385
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• 1992

The effect of antioxidant activity of soyasaponin on the liposomal phospholipid membrane were investigated by spectrophotometry. The oxidation index and oxidation rate of ${\alpha}-tocopherol$ containing egg phosphatidylcholine (EPC) liposomes were markedly decreased in the presence of soyasaponin relative to those of purephospholipid liposmes. ${\alpha}-tocopherol$ containing liposomes delayed the oxidation of liposomes. Especially soyasaponin stimulated the antioxidant activity of ${\alpha}-tocopheroal$ in liposomes. These results indicates that soyasaponin in liposomes had some additive effect on antioxidant of ${\alpha}-tocopherol$ toward liposomes.

• Journal of the korean Society of Automotive Engineers
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• v.5 no.3
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• pp.56-63
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• 1983

강성체로된 견인물체가 탄성무한경면으로 지지된 점탄성층 위를 미끄러져 갈 때 접촉구간에서의 압력분포와 마찰 특성을 고찰하였다. 즉, 접촉구간에서의 강성체의 모양과 압력분포에 관한 적분 방정식을 구하고, 점탄성층의 두께가 접촉구간에 비하여 충분히 두꺼울 때 압력분포와 마찰계 수의 근사해를 구하였다. 압력분포의 모양은 점탄성층의 물성을 표시하는 지수값, 즉 .alpha.<1/2, .alpha.=1/2, .alpha.>1/2에 따라서 크게 다르다. 한편, 수치해석에 의하면 마찰 계수에 대한 근 사해는 강성체의 미끄럼 속도, 점탄성 층의 두께, 탄성체의 영율 (E$_{o}$ )과 점탄성층의 시효 성탄성계수 (E$_{v}$ )의 차, 즉 E$_{o}$ /E$_{v}$ 에 따라 변화함을 알 수 있다. 즉, 탄성체가 점탄성층에 비하여 딱딱하면 할수록, 또 강성체 속도가 느리면 느릴수록 마찰계수는 작아진다. 그리고 불성의 지수(.alpha.)가 커지면 커질수록 근사해의 수렵 속도는 느려지게 되고 지 수(.alpha.)가 1에 가까워지면 점탄성층의 탄성효과는 점성효과에 비하여 거의 무시할 수 있으며 근사해는 의미가 없어지게 된다.

• Korean Journal of Ichthyology
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• v.31 no.4
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• pp.241-248
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• 2019

The freshwater fish fauna for the whole water system of Geogeumdo Island was surveyed at a total 10 sites from March 2018 to February 2019. During the surveyed period, 13 species belonging to 5 families and 4 orders were collected. Cyprinidae (68.84%) and Gobiidae (18.21%) were the dominant family, and the dominant species was Zacco temminckii (53.71%), and the subdominant species was Rhynchocypris oxycephalus (10.78%). Kichulchoia brevifasciata (1.27%) that endangered species were found in this study, but the habitat was confirmed in one site in Sinpyeongcheon compared to previous literature. Three endemic species of Korea were found in this island such as Iksookimia hugowolfeldi (5.07%), Liobagrus somjinensis (2.99%) and K. brevifasciata (1.27%). According to analysis of fish community structure based on average diversity, evenness index, dominance and richness indices in Geogeumdo Island were 1.666, 0.649, 0.645 and 1.713, respectively.

• Tuberculosis and Respiratory Diseases
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• v.61 no.4
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• pp.330-338
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• 2006

Background: The main factors associated with weight loss in patients with COPD are not well known. Since chronic inflammation and oxidative stress play a major pathogenic role in COPD, these factors may be responsible for the patients' weight loss. Therefore, this study measured the body mass index (BMI) in COPD patients and evaluated the variables, such as systemic inflammatory marker, oxidative stress and lung function, that correlate with the BMI. Method: The stable COPD patients (M:F=49:4, mean age=$68.25{\pm}6.32$) were divided into the lower (<18.5), normal (18.5-25) and higher (>25) BMI group. The severity of the airway obstruction was evaluated by measuring the $FEV_1$. The serum IL-6 and TNF-$\alpha$ levels were measured to determine the degree of systemic inflammation, and the carbonyl protein and 8-iso-prostaglandin $F_2{\alpha}$ level was measured to determine the level of oxidative stress. Each value in the COPD patients and normal control was compared with the BMI. Results: 1) Serum 8-iso-prostaglandin $F_2{\alpha}$ in COPD patients was significantly higher ($456.08{\pm}574.12pg/ml$) than that in normal control ($264.74{\pm}143.15pg/ml$) (p<0.05). However, there were no significant differences in the serum IL-6, TNF-$\alpha$, carbonyl protein between the COPD patients and normal controls. 2). In the COPD patients, the $FEV_1$ of the lower BMI group was significantly lower ($0.93{\pm}0.25L$) than that of the normal BMI ($1.34{\pm}0.52L$) and higher BMI groups ($1.72{\pm}0.41L$) (p<0.05). The lower $FEV_1$ was significantly associated with a lower BMI in COPD patients (p=0.002, r=0.42). The BMI of very severe COPD patients was significantly lower ($19.8{\pm}2.57$) than that of the patients with moderate COPD ($22.6{\pm}3.14$) (p<0.05). 3). There were no significant differences in the serum IL-6, TNF-$\alpha$, carbonyl protein and 8-iso-prostaglandin $F_2{\alpha}$ according to the BMI in the COPD patients. Conclusion: The severity of the airway obstruction, not the systemic inflammatory markers and oxidative stress, might be associated with the BMI in stable COPD patients. Further study will be needed to determine the factors associated with the decrease in the BMI of COPD patients.

• The Korean Journal of Applied Statistics
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• v.10 no.1
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• pp.105-119
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• 1997

Barnwal and Paul(1988) derived the likelihood ratio statistic and $C(\alpha)$ statistic for testing the equality of the means of several groups of count data in the presence of a common dispersion parameter. These tests are generalized to be applicable without the restriction of a common dispersion parameter. And the assumed model of data is also extended from negative binomial to double exponential Poisson model. Monte Carlo simulations show the superiority of $C(\alpha)$ statistic based on the double exponential Poisson family which has a very simple form and requires estimates of the parameters only under the null hypothesis.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.312-315
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• 2005

Visual MODFLOW 프로그램 내 MT3D 패키지를 이용하여 다공 추적자 시험 해석 모델을 제시하였으며, 개념모델을 설정하여 추적자 해석 모델 모사 시 입력상수인 수리전도도(K), 비산출률$(S_y)$, 유효공극률$(n_e)$, 종분산지수$({\alpha}_L)$ 및 횡분산지수$({\alpha}_T)$ 등에 따른 민감도를 분석하였다. 또한, 이를 이용하여 부산과 이천지역의 현장 추적자 시험 자료를 해석하였다. 민감도 분석 결과, 유효공극률과 종분산지수의 민감도가 가장 크게 나타났으며, 비산출률의 민감도가 가장 작게 나타났다. 유효공극률은 관측정에서 측정되는 추적자의 최고농도를 결정하는 인자이며, 종분산지수는 추적자 최고농도가 되는 경과시간과 관계가 깊은 것으로 나타났다. 재순환 추적자 시험 해석 모델을 적용한 부산지역의 경우 유효공극률은 0.15, 종분산지수는 5m인 것으로 모사되었으며, 수렴 흐름 추적자 시험 해석 모델을 적용한 이천지역의 경우 유효공극률은 0.01, 종분산지수는 13m로 산정되었다.