• Journal of Korean Association for Spatial Structures
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• v.7 no.2 s.24
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• pp.105-114
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• 2007

Large span spaces have been widely used for various purposes including sports events in other countries. Due to increasing demands on multi-purpose use of such spaces, recently built large span sport facilities such dome stadiums have been required to accommodate sport events as well as performing events. Also, retractable ceilings and/or walls were generally adopted in those spaces for providing various event conditions. It seems obvious that the openings between diffuse fields and free field may cause difficulties in the acoustic design of such spaces In the present work, the acoustic characteristics of non-diffuse field has been investigated using 1/10 acoustic scale models. It was found that RTs at low- and mid-frequencies decayed faster than those at high-frequencies as the percentage of opening area increased. The decay rate of RTs at high frequencies were not influenced by increasing the area of an opening. Also high dependence of EDT on the percentage of opening area was observed at all frequency range. D50 was not improved by increasing the area of an opening up to 12.5% and then sharply increased. The application of Schroeder integration to evaluate the reverberation charateristics of coupled spaces may not be proper, since non-exponential decay process with double or triple decays of those spaces can not be properly defined. EDT seems more appropriate to predict reverberation at the early acoustic design stage of acoustically coupled spaces.

• Journal of The Korean Astronomical Society
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• v.47 no.2
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• pp.77-86
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• 2014

Using a cosmological ${\Lambda}CDM$ simulation, we analyze the differences between the widely-used spin parameters suggested by Peebles and Bullock. The dimensionless spin parameter ${\lambda}$ proposed by Peebles is theoretically well-justified but includes an annoying term, the potential energy, which cannot be directly obtained from observations and is computationally expensive to calculate in numerical simulations. The Bullock's spin parameter ${\lambda}^{\prime}$ avoids this problem assuming the isothermal density profile of a virialized halo in the Newtonian potential model. However, we find that there exists a substantial discrepancy between ${\lambda}$ and ${\lambda}^{\prime}$ depending on the adopted potential model (Newtonian or Plummer) to calculate the halo total energy and that their redshift evolutions differ to each other significantly. Therefore, we introduce a new spin parameter, ${\lambda}^{\prime\prime}$, which is simply designed to roughly recover the value of ${\lambda}$ but to use the same halo quantities as used in ${\lambda}^{\prime}$. If the Plummer potential is adopted, the ${\lambda}^{\prime\prime}$ is related to the Bullock's definition as ${\lambda}^{\prime\prime}=0.80{\times}(1+z)^{-1/12}{\lambda}^{\prime}$. Hence, the new spin parameter ${\lambda}^{\prime\prime}$ distribution becomes consistent with a log-normal distribution frequently seen for the ${\lambda}^{\prime}$ while its mean value is much closer to that of ${\lambda}$. On the other hand, in case of the Newtonian potential model, we obtain the relation of ${\lambda}^{\prime\prime}=(1+z)^{-1/8}{\lambda}^{\prime}$; there is no significant difference at z = 0 as found by others but ${\lambda}^{\prime}$ becomes more overestimated than ${\lambda}$ or ${\lambda}^{\prime\prime}$ at higher redshifts. We also investigate the dependence of halo spin parameters on halo mass and redshift. We clearly show that although the ${\lambda}^{\prime}$ for small-mass halos with $M_h$ < $2{\times}10^{12}M_{\odot}$ seems redshift independent after z = 1, all the spin parameters explored, on the whole, show a stronger correlation with the increasing halo mass at higher redshifts.

• Journal of the Korean Chemical Society
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• v.53 no.2
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• pp.118-124
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• 2009

The values of critical micelle concentration (CMC) and counter ion binding constants (B) in a micellar state of CPC (1-hexadecylpyridinium chloride) with Brij 35 (polyoxyethylene(23) lauryl ether) in water were determined as a function of ${\alpha}_1$ (the overall mole fraction of CPC) by the use of electric conductivity method. Various thermodynamic parameters ($X_i,\;{\gamma}_i,\;C_i,\;a_{i}^{M},\;\beta,\;and\;{\Delta}H_{mix}$) were calculated and analyzed by means of the equations derived from the non-ideal mixed micellar model. And thermodynamic parameters (${\Delta}{G^o}_m,\;{\Delta}{H^o}_m,\;and\;{\Delta}{S^o}_m$) for the micellization of CPC/Brij 35 mixtures were also calculated from the temperature dependence of the CMC values. The values of ${\Delta}{G^o}_m$ are all negative, but the values of ${\Delta}{S^o}_m$ and ${\Delta}{H^o}_m$ are positive or negative, depending on the measured temperature and ${\alpha}_1$.

• Journal of dental hygiene science
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• v.12 no.5
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• pp.516-524
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• 2012

The purpose of this study was to examine the relationship between the smoking experience of some middle school students and their oral health behavior in an effort to provide information on how to teach students to abstain from smoking and improve their oral health behavior to maintain or promote their oral health. The subjects in this study were the students who were in their first, second and third years in four different middle schools located in the city of Iksan, North Jeolla Province. A survey was conducted from June 14 to July 12, 2011, and the collected data were analyzed. The findings of the study were as follows: 1. The students who smoked accounted for 10.6 percent. Out of them, the rates of the boys and the girls respectively stood at 16.0 and 5.4 percent (p<0.001). 2. As for the life satisfaction of the smoker students, 9.5 percent were satisfied, and 15.0 percent were unsatisfied (p<0.05). 3. Concerning a plan for quitting smoking, 71.4 percent of the boys and 45.5 percent of the girls planned to give up smoking (p<0.01). 4. Regarding the links between smoking experience and oral health behavior, the students who had smoking experience got 2.19 in the use of oral hygiene supplies, and the others who hadn't got 1.97 (p<0.01). 5. As to the connections between nicotine dependence and oral health behavior, the students who replied they depended on nicotine got 2.68 in education and concern, and those who answered they never did got 3.21 (p<0.05).

• Journal of the Korean Dietetic Association
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• v.19 no.4
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• pp.343-355
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• 2013

This study analyzed the dietary habits and nutrient intake status of adult drinkers in Korea. Alcohol drinking patterns were obtained from the Korea National Health and Nutrition Examination Survey (KNHANES). Among 4,968 persons, 91.5% were drinkers. Classification of their drinking patterns by the Alcohol Use Disorders Identification Test (AUDIT) score showed 64.5% of the drinkers were normal drinkers, 22.4% problem drinkers and 13.2% alcohol-dependent drinkers. Overall, 47% of the drinkers were considered alcohol-dependent in the Rapid Alcohol Problems Screen (RAPS4). Significant differences were found between those who abstained from alcohol (86.8%) and alcohol-dependent drinkers (68.9%); when asked about breakfast habits 73.4% of non-drinkers often had family meals, while only 55.4% of the alcohol-dependent drinkers had family meals. Dietary energy, alcohol energy, and total energy intake significantly increased for the alcohol-dependents (P<0.001). In addition, the intake of eight nutrients (protein, vitamin A, vitamin $B_1$, vitamin $B_2$, niacin, calcium, phosphorous and iron), significantly increased in the following order (least to highest): abstainers, normal drinkers, drinkers with a moderate addiction to alcohol and alcohol-dependent drinkers (P <0.05). Nutrient Adequacy Ratios (NAR) of all nutrients, except vitamin C, and the Mean nutrient Adequacy Ratio (MAR) significantly increased in the following order (least to highest): abstainers, normal drinkers, drinkers with a moderate addiction to alcohol and alcohol-dependent drinkers (P<0.05). The intake of vitamin $B_1$, vitamin $B_2$, and niacin per 1,000 kcal, according to drinking pattern, decreased in the order of abstainers, normal drinkers, drinkers with a moderate addiction to alcohol, and alcohol-dependent drinkers (P<0.001). The above results show that the nutrient intake of normal drinkers, drinkers with a moderate addiction to alcohol, and alcohol-dependent drinkers are higher than abstainers. However, overall intake of vitamin $B_1$, vitamin $B_2$, and niacin per 1,000 kcal was low. Therefore it is necessary to increase vitamin $B_1$, vitamin $B_2$, and niacin intake for drinkers.

• Membrane Journal
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• v.15 no.3
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• pp.224-232
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• 2005

The use of the lung assist device (LAD) would be well suited for acute respiratory failure (ARF) patients, combining the simplicity of mechanical ventilation with the ability of extracoporeal membrane oxygenators (ECMO) to provide temporary relief for the natural lungs. This study's specific attention was focused on the effect of membrane vibration in the LAD. Quantitative experimental measurements were performed to evaluate the performance of the device, and to identify membrane vibration dependence on blood hemolysis. We tried to decide upon excited frequency band of limit hemolysis when blood hemolysis came to through a membrane vibration action. The excited frequency of the module type 5, consisted of 675 hollow fiber membranes, showed the maximum gas transfer rate. We concluded that the maximum oxygen transfer rate seemed to be caused by the occurrence of maximum amplitude and the transfer of vibration to hollow fiber membranes. It was excited up to $25{\pm}5$ Hz at each blood flow rate of module type 5. We found that this frequency became the 2nd mode resonance riequency of the flexible in blood flow. Blood hemolysis was low at the excited frequency of $25{\pm}5$ Hz. Therefore, we decided that limit hemolysis frequency of this LAD was $25{\pm}5$ Hz.

• Journal of the Economic Geographical Society of Korea
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• v.12 no.4
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• pp.438-453
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• 2009

Attracting advanced foreign enterprises into the less-developed regions has gained increasing importance as a regional development strategy in Korea. This study critically examines the foreign-direct investment-led regional development strategy of Wales, United Kingdom. Despite a high FDI inflow in manufacturing, the Welsh regional economy has suffered from specialization in low-skilled assembly with limited R&D activities, insufficient linkage with local domestic suppliers, and violent fluctuation in local employment in response to changes within the global business environment. This tendency shows that the foreign-invested companies have neither locally embedded themselves enough nor created the external agglomeration economies in the region. At the same time, the Welsh local government's excessive dependence on financial incentives packages to induce multinationals, rather than effort to create regional innovative capacity, has resulted in a sizable fiscal loss, an abused local planning process, and subordination of the local government's major administrative decision-making on foreign investors. The Welsh FDI case suggests that an effective FDI attraction policy should include inter-regional cooperation and coordination in the inward investment attraction procedure, a comprehensive land use planning process, and state-level concrete governance on FDI.

• Journal of the Korean GEO-environmental Society
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• v.11 no.6
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• pp.5-20
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• 2010

One-dimensional equivalent linear site response analysis is widely used in practice due to its simplicity, requiring only few input parameters, and low computational cost. The main limitation of the procedure is that it is essentially a linear method, in which the time dependent change in the soil properties cannot be modeled and constant values of shear modulus and damping is used throughout the duration of the analysis. Various forms of modified equivalent linear analyses have been developed to enhance the accuracy of the equivalent linear method by incorporating the dependence of the shear strain with the loading frequency. The methods are identical in that it uses the shear strain Fourier spectrum as the backbone of the analysis, but differ in the method in which the strain Fourier spectrum is smoothed. This study used two domestically measured soil profiles to perform a series of nonlinear, equivalent linear, and modified equivalent linear site response analyses to verify the accuracy of two modified procedures. The results of the analyses indicate that the modified equivalent linear analysis can highly overestimate the amplification of the high frequency components of the ground motion. The degree of overestimation is dependent on the characteristics of the input ground motion. Use of a motion rich in high frequency contents can result in unrealistic response.

• Journal of Energy Engineering
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• v.23 no.2
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• pp.93-101
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• 2014

How to determine the extent of national energy security? In this paper, we estimate it by comparative analysis of South Korea and other OECD countries in terms of energy diversity (fuel diversity). Energy security consists of 4 key factors such as availability, accessibility, acceptability, affordability. Especially the importance of accessibility can grow as local imbalance of supply and demand increases. As a proxy of the accessibility, fuel diversity can be a significant indicator to estimate a measure of energy security. In this paper, we use Shannon-Wiener index to measure energy diversity. If fuel diversity increases, the stability of energy security also should increase, because of the smoothing effect to lessen dependence on key energy sources. In 2012 Korean growth rate of H-index (energy diversity) is 18.38%, which is higher than other OECD countries. However, Korean H-index itself is 1.93, lesser than other countries. Shift from oil to coals/gas within fossil fuels has more impact on H-index than weight transition from fossil fuels to renewable energies in Korea. We conclude that more renewable energy is an effective solution to achieve higher energy diversity and ultimately higher energy security as the same as the German case.

• Korean Journal of Social Welfare Studies
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• no.37
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• pp.63-89
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• 2008

This study attempts to examine the factors influencing the Caregiving responsibility of sibling without disability on their adult siblings with intellectual disability. For this purpose, a questionnaire survey was conducted on siblings without disability who have adult siblings with intellectual disability aged 18 years old or more and also who use services provided by 8 welfare centers for persons with disabilities in Seoul. With 132 valid responses, multiple regression technique was adopted in exploring a model for characteristics of adult with intellectual disability, a model for characteristics of siblings without disability, a model for relationship factors, and a comprehensive model. The findings of the study showed that the degree of disability in the model for characteristics of adult siblings with intellectual disability and the intimacy of siblings and social support in the model of relationship factors were significant. The result of the comprehensive model revealed that the degree of disability, the gender of the siblings without disability, the intimacy of siblings, and social support were significant. Especially, the relationship factors including the intimacy of siblings and social support were found to be the most significant factors in order to explain the caregiving responsibility. The findings of the study suggest that sibling program needs to be developed and disseminated in order to increase the understanding and the trust between adult with intellectual disability and sibling without disability, that a help is critical for adult with intellectual disability to extend the social network in which sibling without disability receives support from sibling without disability, family, friends, and other acquaintances around, and that different approach is needed in order to reduce caregiveing difficulties depending on the dependence of disability.