• Journal of The Korean Society of Grassland and Forage Science
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• v.9 no.2
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• pp.88-95
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• 1989

This experiment 'was conducted to investigate the grazing cattle's palatability by the method of grazing time on the pasture dominated orchardgrass and on the pasture dominated perennial ryegrass from June to October, 1987. The experiment was carried out on the experimental field at Livestock Ex- Experiment Station. The results are summarized as follows: 1. In summer, the grazing time on the pasture dominated orchardgrass increased in 49.7 min, 57.4 min, 102 min, 118.7 min, respectively as sward height decreased in 50 cm, 45 cm, 35 cm, 23 cm, respectively and their correlation coefficiet was -0.9722*(P <0.05). 2. In autumn, the grazing time on the pasture dominated perennial ryegrass decreased in 182 min, 98.5 min, 49.4 min, 31.9 min, respectively as sward height decreased in 43 cm, 34 cm, 25 cm, 18 cm, respectively and their correlation coefficient was 0.9684*. (P <0.05). 3. Grazing time increased as sward height increased on the pasture dominated perennial ryegrass because the composition rate of orchardgrass and red clover which were palatability on the plot of the high sward height.was many. It was suggested that the factor that could be first related to palatability on mixture pasture was the factor of species than the factor of sward height. 4. When the eating rate on the plot of the low sward height was over 55% as the grazing day went by, it gradually decreased because the eating rate on it was high but the fresh yield was low. After all it seemed that it affected palatability because forage availability on the plot of the low sward height was degenerating.

• Journal of the Korean Data and Information Science Society
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• v.28 no.5
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• pp.1055-1067
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• 2017

Most previous works to study for the depression of the disabilities in Korea have analyzed the repeated measured data of each individual under the mutually independent assumption. In this study, Korea Welfare Panel data of the disabilities surveyed additionally every three years are analyzed to detect the significant exploratory variables by the linear mixed models. A suitable correlation matrix is considered for the dependency of repeated measurement of each individual. The random effect to reflect the characteristics of the individuals as well as the fixed effect is included in the fitted linear mixed model. By the residual plot of the fixed effect model, the problem that the averages of residuals of each individual do not seem to be around zero is described. Further, the residual plot and the Q-Q plot coming from the selected final model are shown that the problem is modified well.

• Journal of Korea Water Resources Association
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• v.42 no.4
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• pp.355-363
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• 2009

The purpose of this paper is to investigate the influence of noise on chaotic time series. We used two time series of Lorenz system and of Great Salt Lake's volume data which are well known as chaotic systems. This study investigated the attractors, correlation dimensions, and Close Returns Plots and Close Returns Histograms of two time series to investigate the influence of noise as increasing noise level. We performed Chi-square test to the relative frequency of Close Returns Histogram from Close Returns Plot for the investigation of stochastic process of chaotic time series as increasing noise level of time series. As the results, two time series were changed from chaotic to stochastic series as noise level is increased. Finally, we analyzed the effect of noise cancellation by using Simple Moving Average method. The results of applications of Simple Moving Average method to Lorenz and GSL time series showed that we could effectively cancel the noise. Then we could confirm the applicability of Simple Moving Average method to cancel the noise for the hydrologic time series having chaotic characteristics.

• Korean Journal of Applied Biomechanics
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• v.21 no.2
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• pp.253-258
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• 2011

The purpose of this study was to compare metabolic energy expenditure with the computed kinetic energy for different speeds of walking and running over the treadmill and to find the relevance for individual and group equation by performing a statistical analysis, Bland-Altman plot. Seven male subjects participated, and they were required to walk and run on the treadmill with the gas analyzer and triaxial accelerometer. Walking speeds were 3.0, 4.0, 5.0 and 6.0 km/h and running speeds were 7.0, 8.0 and 9.0 km/h respectively. Kinetic energy was calculated by the integration of acceleration data and compared with the metabolic energy measured by a gas analyzer. Correlation coefficients showed relatively good between the measured metabolic energy and the calculated kinetic energy. In addition, a dramatic increase in kinetic energy was also observed at the transition speed of walking and running, and two standard deviations in Bland-Altman plot, derived from the difference between measured and predicted values, were 1.14, 2.53, 2.93, 1.80, 2.80, 0.60 and 2.48 respectively. It was showed that there is no difference for methods of how to predict the kinetic energy expenditure for individual and group even though people had each different physical characteristic.

• Journal of The Korean Society of Grassland and Forage Science
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• v.7 no.1
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• pp.18-24
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• 1987

This experiment was carried out to investigate the effects of the final cutting time and cutting height on the winter survival, regrowth, and carbohydrate reserves in stubble, and early spring yield of orchardgrass-dominated pasture before and after the winter season. The experiment was conducted at the experimental field of the Livestock Experiment Station, in Suwon, from October 1985 to early 1986. The results obtained are summarized as follows: 1. Regrowth of plant after the final cut increased significantly (P<0.05) with plot of the early cutting time (Oct. 10) and high cutting height at the final. For winter survival, cut plant should regrow over 15cm in plant height. Therefore limit cutting time and cutting height were forced to be on Oct. 25 and at 6-9cm, respectively. 2. Total water soluble carbohydrate (TSC) content in stubble after the final cut was not significantly changed by different cutting time and cutting height. 3. The percentage of dead plant after wintering was found to be high with plot of the late cutting time and low cutting height at the final cut (P<0.05). And the correlation between the percentage of dead plant after wintering and final plant height before wintering was significantly negathe (r = -0.728**). 4. Fresh and DM yield at the early spring after wintering were increased in the plot of the early cutting time and high cutting height (P<0.05) at the final cut. And significantly positive correlation was observed between the early spring yield and final plant height before wintering (r = 0.720**).

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.1
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• pp.8-13
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• 2015

The objective of this paper is to provide design data of fin-tube heat exchanger which have a large diameter oval tube for dryer application. In this study, the heat transfer and pressure drop performance characteristics of the fin-tube heat exchanger were compared with Dittus-Boelter and a new correlation equation using Wilson plot method. The simulation results based on section by section method were compared with experimental results. These results showed that a new correlation equation using Wilson plot method provided better prediction, about 3 to 12%, than the Dittus-Boelter equation, from the experiment comparison. Also, the pressure drop of simulation results showed much more deviation with the experimental results.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2371-2374
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• 2014

A kinetic study is reported on SNAr reaction of 1-fluoro-2,4-dinitrobenzene with a series of primary amines including hydrazine in $H_2O$ at $25.0^{\circ}C$. The plots of $k_{obsd}$ vs. [amine] are linear and pass through the origin, indicating that general-base catalysis by a second amine molecule is absent. The Br${\o}$nsted-type plot exhibits an excellent linear correlation with ${\beta}_{nuc}$ = 0.46 when hydrazine is excluded from the correlation. The reaction has been suggested to proceed through a stepwise mechanism, in which expulsion of the leaving group occurs after the rate-determining step (RDS). Hydrazine is ca. 10 times more reactive than similarly basic glycylglycine (i.e., the ${\alpha}$-effect). A five-membered cyclic intermediate has been suggested for the reaction with hydrazine, in which intramolecular H-bonding interactions would facilitate expulsion of the leaving group. However, the enhanced leaving-group ability is not responsible for the ${\alpha}$-effect shown by hydrazine because expulsion of the leaving group occurs after RDS. Destabilization of the ground-state of hydrazine through the electronic repulsion between the nonbonding electron pairs is responsible for the ${\alpha}$-effect found in the current $S_NAr$ reaction.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.39-39
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• 2015

극치 수문(Hydrologic extremes)분야에서는 수문자료의 분포에 따라 Gumbel, GEV, 그리고 GLO 분포와 같은 다양한 확률통계 분포형이 존재한다. GEV와 GLO 분포형의 경우 Gumbel 분포형과 달리 형상매개변수가 포함된 3변수 분포형으로써 이상 기후 현상으로 인한 잦은 극치 수문사상을 표현하는데 좀 더 유연한 것으로 알려져 있다. 특히 GLO 분포형의 경우 영국에서 홍수빈도해석 시 적정분포형으로 선정된바 있다(Institute of Hydrology, 1999). 다양한 분포형 중에서 표본 자료를 대표할 수 있는 분포형을 선정하는 통계적 기법이 적합도 검정이다. 적합도 검정에는 $x^2$-검정, Cramer von-Mises 검정, Kolmogorov-Smirnov 검정, PPCC(probability plot correlation coefficient, 확률도시 상관계수)검정 등이 있으며 그 중 PPCC 검정은 이용방법이 간편하면서도 뛰어난 기각능력을 보이는 것으로 알려져 있다. 본 연구에서는 극치 수문분야에서 널리 이용되고 있는 GLO 분포형을 대상으로 자료의 왜곡도 영향을 고려할 수 있는 확률도시 상관계수 검정의 검정통계량을 추정하여 보았다.

• Wind and Structures
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• v.33 no.6
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• pp.423-435
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• 2021

Although existing algorithms can predict wind speed using historical observation data, for engineering feasibility, most use moment methods and probability density functions to estimate fitted parameters. However, extreme wind speed prediction accuracy for long-term return periods is not always dependent on how the optimized frequency distribution curves are obtained; long-term return periods emphasize general distribution effects rather than marginal distributions, which are closely related to potential extreme values. Moreover, there are different wind speed parent sample types; how to theoretically select the proper extreme value distribution is uncertain. The influence of different sampling time intervals has not been evaluated in the fitting process. To overcome these shortcomings, updated steps are introduced, involving parameter sensitivity analysis for different sampling time intervals. The extreme value prediction accuracy of unknown parent samples is also discussed. Probability analysis of mean wind is combined with estimation of the probability plot correlation coefficient and the maximum likelihood method; an iterative estimation algorithm is proposed. With the updated steps and comparison using a Monte Carlo simulation, a fitting policy suitable for different parent distributions is proposed; its feasibility is demonstrated in extreme wind speed evaluations at Longhua and Chuansha meteorological stations in Shanghai, China.

• Asian Journal of Turfgrass Science
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• v.6 no.2
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• pp.73-81
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• 1992

This study was designed to estimate on the interaction of the first productivity, light condition and to examine the ecophysiological 'characteristics of Zoysia japonica. Artificial community of Zoysia japonica was analyzed effect of matter production and growth construction under various shading condition. The results summarized this experiment were as follows ; 1. The relative growth rate(RGR) in all experimental plots was high during the growth stage of 20 days after transplanting and then tend to decrease. RGR value in severe shading or short day condition was remarkably decreased from the early growth stage. 2. The net assimilation rate(NAR) was high during the early growth stage after transplanting. and then decreased the growth proceeded. NAR value in the severe shading or short day condition plots was low. 3. The increasing rate of leaf ared ratio(LAR) was high during the early growth stage after transplanting in the control plot and 30% shading plot, but it appeared to be high 40 days after transplanting in the 50% and 70% shading plot. LAR was appeared to be negative correlation against RGR and NAR. 4. The crop growth rate(CGR) in each experimental plot was increased until 50 days after transplanting, and then decreased. After that time, the maximum CGR value appeared in the control plot(1.56g /g, 10days), 60days after transplanting. CGR had positive correlation with LAI. The optimum LAI in the control, 30%, 50%, and 70% shading plots was appeared as 2.10, 1.75, 1.25, and 0.90.