• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.1
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• pp.140-145
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• 2005

The existing analytical expression for the voltage between the power and ground plane consist of metal-dielectric-metal board is expressed in the two dimensional infinite series. To reduce the computation time, the two dimensional infinite series is converted to the one dimensional infinite series using the summation formula of Fourier series. We applied these equations to the analysis of voltage between the $9‘{\times}4'$ size power-ground plane. The derived one dimensional infinite series shows the more rapid convergency and the more accurate result than the two dimensional infinite series. This equation can be applied to the power-ground plane analysis which needs a lot of the repeating computation.

• Nuclear Engineering and Technology
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• v.26 no.1
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• pp.32-40
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• 1994

A digital control system for the steam generator oater level control is developed using the optimal control technique. To describe the more realistic situation, a feedwater valve actuator of the first order lag is included in the overall control system. The optimal gains are obtained by the LQ method which imposes the constraints on the feedwater valve motion as well as on the deviation between the input demand signal and the output feedwater. Developed also is a Kalman observer on account of the flow measurement uncertainty at low power. And a digital controller on the feedback loop is designed which makes the system maintain the same stability margins for all power ranges. The simulation results show that the optimal digital system has good control characteristics despite the adverse dynamics of the steam generator at low power.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.6
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• pp.71-78
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• 1989

The imput-output relations for nonlinear systems can be explicitly represented by the Volterra series and they can be characterized by the Volterra kernels. This study is concerned with modeling an elastomer force-displacement relation due to step inputs by utilizing the truncated Volterra series. Since it is practically impossible to apply step inputs that have infinite slope at zero time, the loads due to constant penetration(displacement) rate followed by constant penetration inputs are measured as an alternative approach and estimated for step inputs and then utilized for the truncated Volterra series models. One second order and one third order truncated Volterra series models have been employed to model the force-displacement relation which is one of the prominent properties to characterize the viscoelastic material. The third order truncated Volterra series model has better results, compared with those of the second order truncated Volterra series model.

• Journal of the Korean Society for Railway
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• v.13 no.4
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• pp.357-362
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• 2010

The railroad that represents modern industry began appearing in 1899. However, after the steam locomotive that provided water stopped the service, the water towers within the railroad station were useless. Suggestions presented in this study for activating the environment around the water towers that are designated as the cultural properties results are as followed: 1) The place where people can experience the vestiges of Korean War and the region that different novels accommodated. 2) A plaza 3) A facility for exhibition of industry inheritance and local products 4) A local landmark 5) Reproduction of the historical steam locomotive and water tower Local residents should participate in the activation process. And the designer should consider the environmental context. In addition, the activation of water towers should be designed under an urban plan.

• Communications of Mathematical Education
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• v.31 no.1
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• pp.71-84
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• 2017

Taylor series has a complicated structure comprising of various concepts in college major mathematics. This subject is a strong tool which has usefulness and applications not only in calculus, analysis, and complex analysis but also in physics, engineering etc., and other study. However, students have difficulties in understanding mathematical structure of Taylor series convergence correctly. In this study, after classifying students' mathematical characteristic into three categories, we use structural image of Taylor series convergence which associated with mathematical structure and operation acted on that structure. Thus, we try to analyze the understanding of Taylor series convergence and present the results of this study.

• Water for future
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• v.28 no.6
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• pp.147-158
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• 1995

The purpose of this study is to establish a method of estimating the daily urban water demand using statistical model. This method will be used for the development of the efficient management and operation of the water supply facilities. The data used were the daily urban water use, the population, the year lapse and the weather conditions such as temperature, precipitation, relative humidity, etc. Kwangju city was selected for the case study area. The raw data used in this study were rearranged either by month or by season for the purpose of analysis, and the statistical analysis was applied to the data to obtain the regression model. As a result, the multiple linear regression model was developed to estimate the daily urban water use based on the seather condition. The regression constant and the model coefficients were determined for each month of a year. The accuracy of the model was within 3% of average error and within 10% of maximum error. The developed model was found to be useful to the practical operation and management of the water supply facilities.

• Korean Journal of Poultry Science
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• v.47 no.3
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• pp.121-126
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• 2020

This study was conducted to investigate the effect of drinking ion water on the performance, egg quality, and serum biochemical properties of laying hens in a high-temperature environment. A total of 180 laying hens with equal egg production rates were randomly divided into three treatments with five replicates. Treatments were applied from 24 to 27 weeks of age and included the supply of ion water (IW), tap water (TW), and cold water (CW). The results showed that the egg production rate, egg weight, and feed intake of hens were significantly (P<0.01) improved in the IW group compared with those in the TW group but did not differ from those in the CW group. Egg quality parameters such as albumen height, Haugh unit, and eggshell thickness were found to be higher in the IW than in the TW group (P<0.05); however, no significant differences were observed in comparison with the CW group. Serum Ca and P concentrations tended to increase (P<0.10) in the IW group, and serum high-density lipoprotein cholesterol and albumin levels were greater (P<0.05) in response to IW than those to TW. This study provides evidence that the supply of IW can relieve the high-temperature stress during the summer. In particular, because the improved effects of the IW were confirmed to be similar to those of CW, it shows potential as a method to manage the drinking water of hens in the summer season along with the supply of CW.

• Journal of the East Asian Society of Dietary Life
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• v.13 no.5
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• pp.439-446
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• 2003

Various volume of water for the optimal brewing condition of the Korean distilled liquor produced by liquefaction of rice and corn starch was investigated Pilot brewings were carried out by the liquefaction of 5kg of rice and 10kg of corn starch with 150%, 200% and 250% of water regarding the amount of rice and corn starch. The pH, alcohol production and total acidity were normal during the fermentation process. The yield was proportional to the amount of water added and the highest yield was obtained by 250% of water addition without loss of quality. All the test results were not significantly different by the one-way ANOVA and Duncan's multiple range test at p<0.05 and the flavor profiles were also not different according to the amount of water added. As a result, 250% of water addition was the most economical and optimal brewing condition in this study.

• Journal of Korea Water Resources Association
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• v.30 no.1
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• pp.45-54
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• 1997

The correct estimation of the daily or hourly urban water demand is required for the efficient management and operation of the water supply facilities. The prediction of water supply demand are regression model and time series method, the optimum ARIMA (Auto Regressive Integrated Moving Average) model was sought for the daily urban water demand estimation in this paper. The data used for this study were obtained from the city of Kwangju Korea. The raw data used in this study were rearranged 15, 30, 60, 90 days for the purpose of analysis. The statistical analysis was applied to the data to obtain the ARIMA model. As a result, the parameters determining the ARIMA model was obtained. The accuracy of the model was 2% of water supply. The developed model was found to be useful for the practical operation and management of the water supply facilities.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.170-179
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• 2017

We investigated design requirements of feed water drain and hydrogen vent systems for the sodium-water reaction pressure relief system (SWRPRS) of the prototype generation IV sodium cooled fast reactor (PGSFR). We evaluated the areas of the gas vent pipe of the water dump tank and the length of the water drain pipe of the steam generator to rapid drain of the water steam inside the steam generator for the normal and refueling operations, respectively. We also calculated the diameter of the gas vent pipe of the sodium dump tank which met its design pressure.