• Journal of The Korean Society of Clinical Toxicology
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• v.14 no.2
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• pp.144-150
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• 2016

Purpose: Glyphosate is a widely used non-selective herbicide. Previous studies have shown that glyphosate has genotoxicity, and that even low-doses of glyphosate can cause DNA damage. Melatonin is a hormone produced and secreted by the pineal gland that is known to be a potent anti-carcinogen, anti-oxidant, and genetic protector. This study was conducted to investigate the genoprotective effect of melatonin against glyphosate in human blood lymphocytes. Methods: Human peripheral blood was obtained from 15 young, healthy volunteers and cultured under four different toxicologic conditions. The four groups consisted of a control group, glyphosate only group (300 ng/mL), glyphosate with low level of melatonin group ($50{\mu}M$), and glyphosate with high level of melatonin group ($200{\mu}M$). The mean Sister Chromatid Exchange (SCE) frequency of each group was then analyzed. Results: Glyphosate exposed groups had a higher mean SCE frequency ($10.33{\pm}2.50$) than the control group ($6.78{\pm}2.31$, p<0.001). Interestingly, the group that received a low-level of melatonin had a lower mean SCE frequency ($8.67{\pm}2.58$) than the glyphosate-only group, while the group that received a high level of melatonin had a much lower mean SCE frequency ($8.06{\pm}2.50$) than the glyphosate-only group. There was statistical significance. Conclusion: Melatonin exerted a potent gene protective effect against the genotoxicity of glyphosate on human blood lymphocytes in a dose-dependent fashion.

• Wind and Structures
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• v.13 no.6
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• pp.529-556
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• 2010

This paper investigates the correlation of wind characteristics monitored on a cable-stayed bridge. Total five anemoscopes are implemented into the bridge. Two out of 5 anemoscopes in inflow and two out of 5 anemoscopes in wake-flow along the longitudinal direction of the bridge are installed. Four anemoscopes are respectively distributed at two cross-sections. Another anemoscope is installed at the top of the tower. The correlation of mean wind speed and direction, power spectral density, the turbulent intensity and integral length of wind in flow at two cross-sections are investigated. In addition, considering the non-stationary characteristics of wind, the spatial correlation in time-frequency is analyzed using wavelet transform and different phenomenon from those obtained through FFT is observed. The time-frequency analysis further indicates that intermittence, coherence structures and self-similar structures are distinctly observed from fluctuant wind. The flow characteristics around the bridge deck at two positions are also investigated using the field measurement. The results indicate that the mean wind speed decrease when the flow passing through the deck, but the turbulence intensity become much larger and the turbulence integral lengths become much smaller compared with those of inflow. The relationship of RMS (root mean square) of wake-flow and the mean wind speed of inflow is approximately linear. The special structures of wake-flow in time-frequency domain are also analyzed using wavelet transform, which aids to reveal the forming process of wake-flow.

• Phonetics and Speech Sciences
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• v.8 no.4
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• pp.15-22
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• 2016

This study aims to examine whether the fundamental frequency (F0) varies depending on languages or distinguishes between L1 (first language) and L2 (second language) speech and whether the type of materials which vary in control of consonant voicing affects the use of F0-especially, mean F0. For this purpose, we compared productions of two languages produced by Korean L2 learners of English to those of Korean-English bilingual speakers. Twelve Korean L2 speakers of English and twelve Korean-English bilingual speakers participated in this study. The subjects read aloud 22 declarative sentences-balanced and unbalanced-once in English and once in Korean. Mean F0 of Korean was higher than that of English for both speaker groups, and the difference in the value of mean F0 between the Korean and English sentences was different depending on the type of materials that the participants read. With regard to F0 range, the L2 speakers had a larger F0 range in English than in Korean; however, the effect of language on F0 range was not statistically significant for the bilingual speakers. These results indicate that language-specific properties may affect the use of F0, in particular, mean F0.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.4
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• pp.427-432
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• 2010

To reduce the outage probability and to increase the transmission capacity, the importance of repeaters in cellular systems is increasing. But a RF(Radio Frequency) repeater has a problem that the output of the transmit antenna is partially feedback to the receive antenna, which is feedback interference. In this paper, we proposed adaptive Sign-Sign LMS(Least Mean Square) algorithm using correlations for the performance enhancement of RF repeater. The weight vector is updated by using sign of input signal and error signal to the least squared error of the conventional algorithms. When compared with the conventional method, the proposed canceller achieves the maximum 10 dB performance gain in terms of the MSE(Mean Square Error).

• The Journal of the Petrological Society of Korea
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• v.25 no.1
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• pp.13-27
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• 2016

The characteristics of the rock cleavage inherent in Jurassic granite from Geochang were analysed. The phases of distribution of microcrack spacings were derived from the enlarged photomicrographs(${\times}6.7$) of the thin section. The evaluation for the six directions of rock cleavages was performed using nine parameters such as (1) frequency of microcrack spacing(N), (2) frequency ratio(${\leq}1mm$ and 4 mm >) to total spacing frequency(N:191), (3) spacing ratio(${\leq}1mm$) to total spacing(118.49 mm), (4) mean spacing($S_{mean}$), (5) difference value($S_{mean}-S_{median}$) between mean spacing and median spacing($S_{median}$), (6) density of spacing, (7) median spacing, (8) reduction ratio of spacing frequency to length frequency and (9) magnitude of exponent(${\lambda}$ and b) related to the distribution type of diagram. Especially the close dependence between the above spacing parameters and the parameters from the spacing-cumulative frequency diagrams was derived. The results of correlation analysis between the values of parameters for three rock cleavages and those for three planes are as follows. The values of (I) parameters(1, 2 and 3), (II) parameters(4, 5 and 6), (III) parameter(7), (IV) parameter(8) and (V) parameter(9) show the various orders of H(hardway, H1+H2) < G(grain, G1+G2) < R(rift, R1+R2), R < G < H, R < H < G, G < H < R and H < G < R, respectively. On the contrary, the values of the above four groups(I~IV) of parameters for three planes show reverse orders. This type of correlation analysis is useful for discriminating three quarrying planes. Six spacing-cumulative frequency diagrams were arranged in increasing order on the value of main parameter($S_{mean}-S_{median}$). These diagrams show an order of R2 < R1 < G2 < G1 < H2 < H1 from the related chart. In other words, the above six diagrams can be summarized in order of rift(R1+R2) < grain(G1+G2) < hardway(H1+H2). These results indicate a relative magnitude of rock cleavage related to microcrack spacing. Especially, the above main parameter could provide advanced information for prediction the order of arrangement among the diagrams.

• Korean Journal of Community Nutrition
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• v.12 no.1
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• pp.13-24
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• 2007

This study was to investigate dietary life and eating-out style related to breakfast frequency of male students in culinary college. This survey was conducted using questionnaires for 110 male students at college in Hongseung. Mean height and body weight of those we investigated was 174 cm and 70.5 kg. The one to two times per week breakfast eating group was 34.55%, which is exceedingly numerous; none per week breakfast eating group was 30%; three to tow times per week breakfast eating group was 15.45%; everyday breakfast eating group was only 9.09%. The breakfast frequency was very low, and the not-eating breakfast problem is serious to think of in male college students. Mean weight, body fat and body mass index(BMI) of the everyday breakfast eating group was lower than the other group even it was not significant. The self-boarding house or dormitory living condition group was not eating breakfast was significant. So a correct dietary lift and eating habit should be taught further for male college students. The smoking group was a significant low frequency of breakfast eating, as well as the lower frequency of breakfast, or worse recognition of self health condition. Higher frequency of breakfast showed more contentment of self body weight. Cooked rice was significantly the most preferable for breakfast. The lower breakfast frequency tended to eat breads or cereals. The lower frequency of breakfast, self recognition of eating rate as speedier was significant, and tended to have a higher frequency of eating-out because of being annoyed by cooking. The lower breakfast frequency ate out more. Twenty five percent of the everyday breakfast eating group ate out because of a special day, and thirty five percent of the not eating breakfast group did so because of being annoyed by cooking. Their mean dietary evaluation grade was under the normal grade, which means that culinary college male students' dietary lives were poor. The lower frequency of breakfast and lower grade of food life evaluation, indicates the importance of nutritional breakfasts education should be improved for male culinary college students also.

• Journal of Korea Water Resources Association
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• v.38 no.1
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• pp.1-9
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• 2005

The study shows the possible use of the index flood frequency curves for an estimation of flood quantiles at ungauged locations. Flood frequency analysis were made for the annual maximum flood data series at 9 available stations in the Han river basin. From the flood frquency curve at each station the mean annual flood of 2.33-year return period was determined and the ratios of the flood magnitude of various return period to the mean annual flood at each station were averaged throughout the Han river basin, resulting mean flood ratios of different return periods. A correlation analysis was made between the mean annual flood and physiographic parameters of the watersheds i.e, the watershed area and mean river channel slope, resulting an empirical multiple linear regression equation over the whole Han river basin. For unguaged watershed the flood of a specified return period could be estimated by multiplying the mead flood ratio corresponding the return period with the mean annual flood computed by the empirical formula developed in terms of the watershed area and river channel slope. To verify the applicability of the methodology developed in the present study the floods of various return periods determined for the watershed in the river channel improvement plan formulation by the Ministry of Construction and Transportation(MOCT) were compared with those estimated by the present method. The result proved a resonable agreement up to the watershed area of approximately 2,000k $m^2$. It is suggested that the practice of design flood estimation based on the rainfall-runoff analysis might have to be reevaluated because it involves too much uncertainties in the hydrologic data and rainfall-runoff model calibration.

• Journal of Biomedical Engineering Research
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• v.14 no.1
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• pp.89-96
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• 1993

During high frequency ventilation (HFV), mean alveolar pressure has been measured to increase with mean airway opening pressure controlled at a constant level in both humans and experimental animals. Since this phenomenon could potentiate barotrauma limiting advantages of HFV, the present study theoretically predicted the difference between menu alveolar and airway opening pressures ($MP_{alv}$). In a Weibel's trumpet airway model, approximated formula for $MP_{alv}$ was derived based on momentum conservation assuming a uniform velocity profile. The prediction, equation was a func pion of gas density($\rho$), mean flow rate(Q), and diameter of the airway opening where the pressure measurement was made($D_0$) : $MP_{alv}=4{\rho}(Q/D_0^{2})^2$. This was a result of the difference in crosssectional area between the alveoli and the airway opening. A simple aireway model experiment was performed and the results well fitted to the prediction, which demonstrated the validity of the present analysis. Previously reported $MP_{alv}$ data from anesthetized dogs in supine position were comparable to the predicted values, indicating that the observed dissociation between mean alveolar and airway opening pressures during HFV can be explained by this innate geometric (or cross-sectional area) asymmetry of the airways. In lateral position, however, the prediction substantially underestimated the measurements suggesting involvement of other important physiological mechanisms.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.727-732
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• 2001

The purpose of this study is to compare the time mean velocity distribution, the time mean kinetic energy, and the time mean turbulence intensity between vertical and horizontal flow fields in a coaxial circular pipe by PIV measurement. Experiments are performed at a Reynolds number 2,000, measuring regions divided as the section regions A, B, C, D in flow fields. The angle of the high-frequency ultrasonic is selected in the direction of $45^{\circ}$ to the flow axes and it is reflected several times. In results, it is clarified that the effect of gravity is given in the vertical flow field compared with the horizontal flow field and the ultrasonic affects the turbulence enhancement. And kinetic energy and turbulence intensity with ultrasonic are shown slightly bigger than those in flow field without it.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2261-2266
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• 2011

Being the most widely used in ultrasound Doppler color flow mapping, the Kasai algorithm, also known as lag-1 autocorrelation method, is capable of estimating the Doppler mean frequency relatively accurately with a modest amount of computation. Particularly in the case of imaging deep lying areas, however, its performance suffers due to low signal-to-noise ratios. The purpose of this paper is to propose a dealiased lag-2 autocorrelation method which is superior to the Kasai algorithm even at low signal-to-noise ratios and to compare their performances through simulations. The proposed algorithm is found to be better by about 2 to 3 dB than the Kasai algorithm in terms of Doppler mean frequency estimation error in the presence of measurement noise.