• 한국농공학회논문집
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• 제51권3호
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• pp.53-62
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• 2009

This study was carried out to select optimal probability distribution based on design accumulated monthly mean inflow from the viewpoint of drought by Gamma (GAM), Generalized extreme value (GEV), Generalized logistic (GLO), Generalized normal (GNO), Generalized pareto (GPA), Gumbel (GUM), Normal (NOR), Pearson type 3 (PT3), Wakeby (WAK) and Kappa (KAP) distributions for the observed accumulative monthly mean inflow of Chungjudam. L-moment ratio was calculated using observed accumulative monthly mean inflow. Parameters of 10 probability distributions were estimated by the method of L-moments with the observed accumulated monthly mean inflow. Design accumulated monthly mean inflows obtained by the method of L-moments using different methods for plotting positions formulas in the 10 probability distributions were compared by relative mean error (RME) and relative absolute error (RAE) respectively. It has shown that the design accumulative monthly mean inflow derived by the method of L-moments using Weibull plotting position formula in WAK and KAP distributions were much closer to those of the observed accumulative monthly mean inflow in comparison with those obtained by the method of L-moment with the different formulas for plotting positions in other distributions from the viewpoint of RME and RAE.

• Journal of Nutrition and Health
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• 제36권8호
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• pp.851-858
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• 2003

Sister chromatid exchange (SCE) has recently become a common cytogenic assay system for detecting exposure to chemical mutagens and carcinogens. One application of SCE is the monitoring of populations believed to have been exposed to such agents. A cross-sectional study of SCE frequency in peripheral blood lymphocytes from 45 Koreans aged 61 to 84 years was conducted. The effect of cigarette smoking and age on SCE was assessed by different degrees of smoking status such as smokers (n = 14), ex-smokers (n = 16) and non-smokers (n = 15). Mean spontaneous SCE per cell for the smokers (11.5 $\pm$ 1.1) was significantly higher (p < 0.05) than that for the non-smokers (8.8 $\pm$ 0.3). However, mean SCE frequencies per cell for the ex-smokers (10.3 $\pm$ 0.6) were not significantly different from those of the smokers or the non-smokers. The smokers showed an increased number of high SCE frequency cells (HFCs) when compared to the ex-smokers and non-smokers (p < 0.05). The mean SCE frequencies of the non-smokers showed a statistically significant increase (p < 0.05) with the subject's age. These results show that age and smoking habits contribute a great deal in setting a higher degree of basal DNA damage in elderly Koreans, and smoking appeared to be a more significant damaging factor than age.

• 한국도로학회논문집
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• 제15권6호
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• pp.79-91
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• 2013

PURPOSES : The methods of measuring the sound from the noise source are Pass-by method and NCPX (Noble Close Proximity) method. These measuring methods were used to determine the linkage of TAPL (Total Acoustic Pressure Level) and SPL (Sound Pressure Level) in terms of frequencies. METHODS : The frequency analysis methods are DFT (Discrete Fourier Transform) and FFT (Fast Fourier Transform), CPB (Constant Percentage Bandwidth). The CPB analysis was used in this study, based on the 1/3 octave band option configured for the frequency analysis. Furthermore, the regression analysis was used at the condition related to the sound attenuation effect. The MPE (Mean Percentage Error) and RMSE (Root Mean Squared Error) were utilized for calculating the error. RESULTS : From the results of the CPB frequency analysis, the predicted SPL along the frequency has 99.1% maximum precision with the measured SPL, resulting in roughly 1 dB(A) error. The TAPL results have precision by 99.37% with the measured TAPL. The predicted TAPL results at this study by using the SPL prediction model along the frequency have the maximum precision of 98.37% with the vehicle velocity. CONCLUSIONS : The Predicted SPL model along the frequency and the TAPL result by using the predicted SPL model have a high level of accuracy through this study. But the vehicle velocity-TAPL prediction model from the previous study by using the log regression analysis cannot be consistent with the TAPL result by using the predicted SPL model.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 추계학술대회 논문집
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• pp.28-33
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• 1992

The paper describes a new mean specific cutting pressure model in order to improve the accuracy of prediction of cutting force for face milling. The new mean specific cutting pressure model produces a mean specific cutting pressure and coefficients applied to existing cutting model not by traditional method but by considering intermittence and variation of chip width according to insert cutting position to take into cutter geometry machining condition and width of workpiece, and considering a mean measure force according to spindle eccentricity and mean measure force according to spindle eccentricity and insert initial position errors.. The simulated forces in X, Y, Z directions resulted from the simulated cutting model and the new cutting model are compared with measured forces in the time end frequency domains. The simulated forces in the time and frequency domains. The simulated forces resulted from the new cutting model have a good degreement with measured forces in comparison with these resulted from the existing cutting model

• 대한의용생체공학회:의공학회지
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• 제11권2호
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• pp.203-208
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• 1990

A possible asymmetry in airway inertance was modeled based on previously reported radiographic visualization data of the airway wall fluctuation in intact dogs. Effects of asymmetric Inertance on mean lung volume during high frequency ventilation (HFV) were evaluated in terms of mean inertive pressure drop across the airways. It was found that a negligible inertlve pressure drop was expected ($<1{\;}cmH_20$) in normal subjects, while a sig- nificant rise in mean alveolar pressure compared to mean mouth pressure by approximately $3{\;}cmH_20$ was resulted for about 40% airway fluctuation representing bronchoconstriction state by Histamine induction. These results demonstrate that asymmetric Inertance could lead patients with airway diseases to a significant lung hyperinflation (LHI), and bronchodilation treatment is recommended prior to applying HFV to prevent those patients from a possible barotrauma.

• 한국산학기술학회논문지
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• 제21권2호
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• pp.124-132
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• 2020

본 연구는 노년기 Alpha 리듬의 진폭, 비대칭 및 평균 주파수가 뇌건강 상태를 반영할 수 있는 뇌파 지표로써 임상적 활용 가능성이 있는지 알아보고자 하였다. 이를 위하여 평균 나이 73세 남녀 노인 72명을 대상으로 폐안 시 전전두엽의 뇌파를 4분간 측정하였다. 집단 구분은 Alpha 진폭, 비대칭 및 평균주파수의 평균값을 각각 기준으로 높은집단과 낮은집단으로 분류하였다. 뇌파 지표들 간 상관관계와 t-검정을 실시한 결과는 다음과 같다. 첫 번째, Alpha 진폭이 높아지면 육체적·정신적 스트레스 저항도와 좌·우뇌 소통수준도 높아졌으며, Alpha 평균주파수 위치는 낮아졌다. 또한 Alpha 비대칭이 높아지면 좌·우뇌의 소통수준은 낮아지는 상관관계를 보였다. 두 번째, 좌뇌에 비해 우뇌의 Alpha 파워가 높아지면 Alpha 진폭과 정신적 스트레스 저항도, 좌·우뇌 소통수준도 높아졌다. 세 번째, Alpha 평균주파수 위치가 높아지면 Alpha 진폭과 정신적 항스트레스 지표는 낮아지고 각성 수준은 높아졌다. 이상과 같이 정량화 뇌파 지표들은 서로 간 관련성이 높고, 보완적 의미가 있어 노년기 뇌건강 상태를 반영하는 생체 표지자로써의 가능성을 보여주었다.

• 부모자녀건강학회지
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• 제3권2호
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• pp.41-48
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• 2000

The sleep is the most important problem for new parents. However, there were very rare the study about sleep of normal neonates and early infants in Korea. So we attempted pilot survey study of neonates' sleep pattern. The purpose of this study was to investigate the sleep pattern of normal neonates in Seoul and Kyungki area and to provide for basis for nursing intervention for parents of them. The subjects of this study were 37 normal full-term neonates of 2~3weeks of age who were visited by researcher or assistant at postpartum care unit, health care clinic, outpatient clinic located in Seoul and Kyungki area from April 20, 1999 to March 15, 2000. This study was descriptive survey study under the convenient sampling method. The instrument of this study was the NCASA translated by Korean Parent Child Health Academic Association. The collected data were coded as 1/4hour unit, and analyzed by MS Office Excel program. The result of this study were as followed: 1. The mean amount of total sleep was 15.1hours. The mean amount of daytime sleep was 9.5hours. The mean amount of nighttime sleep was 5.7 hours. The mean amount of longest sleep was 2.9hours. The mean amount of shortest sleep was 0.6hour. 2. The mean amount of total activity was 8.9hours. The mean amount of daytime activity was 6.5 hours. The mean amount of nighttime activity was 2.3hours. The frequency of feeding was 10.4 times a day. The frequency of daytime feeding was 7.3 times. The frequency of nighttime feeding was 3.1 times. It is suggested that various subjects and more data according to age, and comparative study among different cultures are needed for further study in the future.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1338-1341
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• 2002

The Weibull probability density function and the Rayleigh function are compared by analyzing the relations of the capacity factors which are compared the actual wind speed frequency curve with which are modelled using the probability density functions with different mean wind speeds. For this analysis, the wind speed means of arithmetic, root mean square, cubic mean cuberoot, and standard deviations are computed from the measured wind speed data of a specific site and the coefficients of probability density functions are calculated. The capacity factors for Vestas 850[kW] wind turbine are calculated and analyzed. The results shows that the wind speed frequency curve by Rayleigh function is more close to the actual curve than by Weibull function. The more the wind speed frequency curve is close to the actual one, the more the capacity factors become large values.

• 한국대기환경학회지
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• 제5권1호
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• pp.88-95
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• 1989

The aspects of the occurence frequency of $SO_2$ concentration were studied with the observed data in Seoul and the scheme that is capable of estimating not only highest concentration for a variety of averaging times but also concentrations for arbitary occurrence frequency with long term arithmatic mean and geometric standard deviation data, was evaluated. The results of the statistical analysis show that the occurrence frequency is almost log normal except a few cases, and 3rd highest values of daily mean concentration were about 4.2 $\sim$ 5.2 times higher than annual arithmatic mean. The evaluation with the observed hourly concentration shows that the scheme fairly well estimate the short concentration of arbitary occurrence frequence and it can be used for air quality management and environmental impact assessment.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1985년도 학술발표회 논문집
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• pp.87-94
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• 1985

In this paper, enhancement of speech corrupted by additive white or colored noise is stuided. The nuconstrained frequency-domain block least-mean-square (UFBLMS) adaptation algorithm and its frequency-weighted version are newly applied to speech enhancement. For enhancement of speech degraded by white noise, the performance of the UFBLMS algorithm is superior to the spectral subtraction method or Wiener filtering technique by more than 3 dB in segmented frequency-weighted signal-to-noise ratio(FWSNERSEG) when SNR of speech is in the range of 0 to 10 dB. As for enhancement of noisy speech corrupted by colored noise, the UFBLMS algorithm is superior to that of the spectral subtraction method by about 3 to 5 dB in FWSNRSEG. Also, it yields better performance by about 2 dB in FWSNR and FWSNRSEG than that of time-domain least-mean-square (TLMS) adaptive prediction filter(APF). In view of the computational complexity and performance improvement in speech quality and intelligibility, the frequency-weighted UFBLMS algorithm appears to yield the best performance among various algorithms in enhancing noisy speech corrupted by white or colored noise.