• Journal of Power System Engineering
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• v.14 no.6
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• pp.75-82
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• 2010

In this study, the topics for free-surface wave simulation, nonlinear hydrodynamic force, and the critical resonance frequency of so-called ${\tau}=U{\omega}/g$=1/4 are discussed. A high-order spectral/boundary element method is newly adapted as an efficient numerical tool. This method is one of the most efficient numerical methods by which the nonlinear gravity waves can be simulated and hydrodynamic forces also can be calculated in time domain. In this method, the velocity potential is expressed as the sum of surface potential and body potential. Then, surface potential is solved by using the high-order spectral method and body potential is solved by using the high-order boundary element method. By the combination of these two methods, the wave-making problems by a submerged sphere oscillating with forward speed under the free-surface are solved in time domain.

• Journal of Animal Science and Technology
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• v.48 no.6
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• pp.889-896
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• 2006

This study was arranged to investigate effects of maternal nursing potential on immune metabolites in blood, body weight gain and occurrence of disease in Hanwoo calves. Forty experimental calves were used and allocated into two groups with different maternal nursing potential. Thus, high or low maternal nursing potential group had twenty calves, respectively. The concentrations of IGF-I, RBC, Ca and IP in blood were similar between two groups, except for RBC. RBC concentration in blood from high maternal nursing potential group was significantly higher compared with low maternal nursing potential group at 5 days after birth (p<0.05). The concentrations of IgG, albumin, total protein and GGT in blood were similar between two groups during the whole experimental period. The days from birth had no effects on the concentration of IgG, albumin and GGT in blood from two groups, except for total protein. Similarly, the maternal nursing potential had no direct effect on body weight of calves, but body weight in high maternal nursing potential group tended to be higher compared with low maternal nursing potential group at 6 months age. The occurrence of respiratory disease and diarrhea in high maternal nursing potential group was relatively lower compared with low maternal nursing potential group. Therefore, the present study indicating that maternal nursing potential had effect on growth, and immune system in relation to disease in calves.

• Korean Journal of Mathematics
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• v.20 no.3
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• pp.323-331
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• 2012

We present a high-order potential ow model for the motion of the impulsively accelerated unstable interface of infinite density jump. The Layzer model for the evolution of the interface is extended to high-order. The time-evolution solutions of the bubble and the spike in the interface are obtained from the high-order model. We show that the high-order model gives improvement on the prediction of the evolution of the bubble and the spike.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.16 no.4
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• pp.225-234
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• 2012

We present two high-order potential flow models for the evolution of the interface in the Rayleigh-Taylor instability in two dimensions. One is the source-flow model and the other is the Layzer-type model which is based on an analytic potential. The late-time asymptotic solution of the source-flow model for arbitrary density jump is obtained. The asymptotic bubble curvature is found to be independent to the density jump of the fluids. We also give the time-evolution solutions of the two models by integrating equations numerically. We show that the two high-order models give more accurate solutions for the bubble evolution than their low-order models, but the solution of the source-flow model agrees much better with the numerical solution than the Layzer model.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1583-1585
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• 1994

In this paper, we investigated the relationship between the needle electrode current and the needle electrode potential, The needle electrode potentials have influence on the needle electrode currents absolutely. So, to increase the needle electrode currents there is necessary to keep a high electric field if the charge reducer. for this, high insulation materials must be selected, and charge density of insulating oil must be high. In this experiment, the more a charge density of insulating oil increases, the more a needle electrode potential increases. So we could know what increasement of needle electrode potential increases a needle electrode current.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.6
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• pp.141-150
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• 2021

In order to assess the impact of climate change on irrigation reservoirs, climate exposure (EI), sensitivity (SI), and potential impact (PI) were evaluated for 1,651 reservoirs nationwide. Climate exposure and sensitivity by each reservoir were calculated using data collected from 2011 to 2020 for seven proxy variables (e.g. annual rainfall) and six proxy variables (e.g. irrigation days), respectively. The potential impact was calculated as the weighted sum of climate exposure and sensitivity, and was classified into four levels: 'Low (PI<0.4)', 'Medium (PI<0.6)', 'High (PI<0.8)', and 'Critical (PI≥0.8)'. The result showed that both the climate exposure index and the sensitivity index were on average high in Daegu and Gyeongbuk with high temperature and low rainfall. About 79.8% of irrigation reservoirs in Daegu, Gyeongbuk, and Ulsan with high climate exposure and sensitivity resulted in a 'High' level of potential impact. On the contrary, 64.5% of the study reservoirs in Gyeongnam and Gangwon showed 'Low' in potential impact. In further studies, it is required to reorganize the proxy variables and the weights in accordance with practical alternatives for improving adaptive capacity to drought, and it is expected to contribute to establishing a framework for vulnerability assessment of an irrigation reservoir.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.3
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• pp.134-141
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• 2006

A potential transformer(PT) has ratio error and phase angle error. Precise measurement of the errors of PT can be achieved using high voltage capacitance bridge, high voltage capacitor and low voltage capacitor. The uncertainty for this method is evaluated and found to be $20{\times}10^{-6}$ in both ratio error and phase angle error. The values measured for PT using the method are well consistent with the those measured for same PT in NMIA(National Measurement Institute of Australia) within the corresponding uncertainty.

• Journal of Plant Biology
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• v.37 no.3
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• pp.343-347
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• 1994

In order to compare the adjustment of 6 oak species to water stress, the components of water status, tissue elastic modulus, free proline content of leaves and morphological characteristics were determined in pot culture. uercus dentata and . mongolica responded effectively to drought with high root : shoot (R/S) ratio or maintenance of high turgor pressure by large and fast osmotic adjustment and . variabilis with maintenance of high turgor pressure by low elastic modulus under drought. Meanwhile, . aliena and . serrata responded effectively with low omotic potential (Ψo) at full saturation and . acutissima with long root in spite of rigid cell wall and high osmotic potential (Ψo) at full saturation. Proline content in leaves of . dentata, . mongolica and . aliena increased early and rapidly at high leaf water potential (Ψleaf). The results indicate that 6 oak species have adjustment different from each other to water stress.

• Korean Journal of Health Education and Promotion
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• v.30 no.2
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• pp.1-10
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• 2013

Objectives: The objective of this study was to assess the relationship between internet addiction and health behaviors & mental health among Korean adolescents. Methods: Data from the 2010 Korean Youth Risk Behavior Web-based Survey was analyzed. Using the Korean Internet Addiction Proneness Scale for Youth-Short Form: Self Report developed by the Korean National Information Society Agency in 2008, subjects were classified into 3 groups for internet addiction including general user, potential-risk group, and high-risk group. The health behaviors and mental health were compared among the groups for internet addiction by gender. Results: There was significantly higher prevalence of internet addiction including potential-risk group and high-risk group in boys(14.1%) than in girls(8.8%). There were significant odds ratios of perceived stress, perceived depression, perceived health and happiness, and satisfaction of sleeping in both genders at potential-risk group and high-risk group compared to general user for the internet addiction. The odds ratios of smoking at high risk group, alcohol drinking at potential risk group, eating breakfast at high risk group, and moderate physical activity at both risk groups among boys were significant. Among girls at both risk group, the odds ratios of smoking, alcohol drinking, and eating breakfast were significant. Conclusions: This study reveals a significant association among internet addiction, and health behaviors, and mental health in Korean adolescents.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.8
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• pp.3606-3629
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• 2018

The discovered high potential utility itemsets (HPUIs) have significant influence on a variety of areas, such as retail marketing, web click analysis, and biological gene analysis. Thus, in this paper, we propose an algorithm called HPUIM-QGA (Mining high potential utility itemsets based on a quantum genetic algorithm) to mine HPUIs over uncertain datasets based on a quantum genetic algorithm (QGA). The proposed algorithm not only can handle the problem of the non-downward closure property by developing an upper bound of the potential utility (UBPU) (which prunes the unpromising itemsets in the early stage) but can also handle the problem of combinatorial explosion by introducing a QGA, which finds optimal solutions quickly and needs to set only very few parameters. Furthermore, a pruning strategy has been designed to avoid the meaningless and redundant itemsets that are generated in the evolution process of the QGA. As proof of the HPUIM-QGA, a substantial number of experiments are performed on the runtime, memory usage, analysis of the discovered itemsets and the convergence on real-life and synthetic datasets. The results show that our proposed algorithm is reasonable and acceptable for mining meaningful HPUIs from uncertain datasets.