• Journal of Korean Association for Spatial Structures
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• v.11 no.4
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• pp.61-69
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• 2011

It is hard to predict the mechanical characteristics of discontinuous stone masonry structures with the use of by the static analysis method, because of irregularity of face stones and also due to randomness of backfill materials. Inversely, one can estimate the mechanical characteristics by comparing the natural frequencies between measured from the field tests and computed from the analytical models. The aim of this paper is to investigate the effectiveness and confidence of the computational modeling method of ancient stone arch bridges in Korea and to find the factors influencing their dynamic characteristics. The results revealed that the rigidity of spandrel walls and backfill materials are the most important factors influencing the natural frequencies of stone arch bridges, which are the critical for the stability of the stone arch structure.

• The Journal of the Acoustical Society of Korea
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• v.40 no.3
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• pp.192-200
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• 2021

Korean bell is a macroscopically axi-symmetrical structure, but has a slight asymmetry due to complex patterns and casting irregularity. Small asymmetry separates one vibration mode into a mode pair with slight frequency difference. The mode pair interferes and creates a beat. The vivid beat with an appropriate period makes the bell sound magnificent and lively feeling. In this study, we propose a method to make the vivid beat using artificial dumshoi. This method creates the vivid beat by designing artificial dumshoi that overwhelms the bell asymmetry. To this end, the asymmetry of Korean bell is quantified by analyzing the beat period data of a number of Korean bells cast in modern times. Based on the measured beat period data, the magnitude of asymmetry is quantified using an equivalent bell model and artificial dumshoi is applied. The movement of mode pair by dumshoi is predicted through finite element analysis. Finally, a design example of the artificial dumshoi for clear beat is introduced.

• Journal of the Society of Disaster Information
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• v.7 no.4
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• pp.259-265
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• 2011

After the commercial opening of the KTX in 2005, the high speed railroad has been rapidly emerged as the major transportation means due to its high energy efficiency. Recently, the government has announced its plan to build the future transportation system around the high speed railroad. Based on this policy, the existing lines as well as the lines under construction or design are planning to increase design speed. In this paper, the suitability of the mid-span PSC girder bridges for the high speed railroad is evaluated via dynamic analysis. IT, Precom, and WPC girder bridges are considered for the purpose of this study and, for comparison, the identical modeling method and the analysis technique are utilized. The performance indices used for dynamic performance evaluation are the natural frequency, the vertical displacement, the end axial displacement, track irregularity, etc. The KTX train is utilized as a dynamic load, and the dynamic analysis is performed up to the train speed of 420km/hr with the increment of 10km/hr.

• KIISE Transactions on Computing Practices
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• v.23 no.9
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• pp.557-563
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• 2017

When large-scale gene expression data are analyzed using lasso regression, the estimation of regression coefficients may be unstable due to the highly correlated expression values between associated genes. This irregularity, in which the coefficients are reduced by L1 regularization, causes difficulty in variable selection. To address this problem, we propose a regression model which exploits the repetitive bootstrapping of gene expression values prior to lasso regression. The genes selected with high frequency were used to build each regression model. Our experimental results show that several genes were consistently selected in all regression models and we verified that these genes were not false positives. We also identified that the sign distribution of the regression coefficients of the selected genes from each model was correlated to the real dependent variables.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2005.09a
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• pp.201-212
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• 2005

[ $Epoxy/BaTiO_3$ ] composite embedded capacitor films (ECFs) were newly designed fur high dielectric constant and low tolerance (less than ${\pm}15\%$) embedded capacitor fabrication for organic substrates. In terms of material formulation, ECFs are composed of specially formulated epoxy resin and latent curing agent, and in terms of coating process, a comma roll coating method is used for uniform film thickness in large area. Dielectric constant of $BaTiO_3\;&\;SrTiO_3$ composite ECF is measured with MIM capacitor at 100 kHz using LCR meter. Dielectric constant of $BaTiO_3$ ECF is bigger than that of $SrTiO_3$ ECF, and it is due to difference of permittivity of $BaTiO_3\;and\;SrTiO_3$ particles. Dielectric constant of $BaTiO_3\;&\;SrTiO_3$ ECF in high frequency range $(0.5\~10GHz)$ is measured using cavity resonance method. In order to estimate dielectric constant, the reflection coefficient is measured with a network analyzer. Dielectric constant is calculated by observing the frequencies of the resonant cavity modes. About both powders, calculated dielectric constants in this frequency range are about 3/4 of the dielectric constants at 1 MHz. This difference is due to the decrease of the dielectric constant of epoxy matrix. For $BaTiO_3$ ECF, there is the dielectric relaxation at $5\~9GHz$. It is due to changing of polarization mode of $BaTiO_3$ powder. In the case of $SrTiO_3$ ECF, there is no relaxation up to 10GHz. Alternative material for embedded capacitor fabrication is $epoxy/BaTiO_3$ composite embedded capacitor paste (ECP). It uses similar materials formulation like ECF and a screen printing method for film coating. The screen printing method has the advantage of forming capacitor partially in desired part. But the screen printing makes surface irregularity during mask peel-off, Surface flatness is significantly improved by adding some additives and by applying pressure during curing. As a result, dielectric layer with improved thickness uniformity is successfully demonstrated. Using $epoxy/BaTiO_3$ composite ECP, dielectric constant of 63 and specific capacitance of 5.1nF/cm2 were achieved.

• The Korean Journal of Zoology
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• v.14 no.4
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• pp.175-180
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• 1971

The effects of X-irradiation on the mitotic activity, the chromosome aberration and the DNA synthetic pattern in synchronized human kidney cells treated with 5-AU were measured in the present experiment. When 5-AU was added, mitotic activity was markedly suppressed. After removal of the cells from the chemical, its activity proceeded synchronouly and reached peaks at hours 10. In 5-AU+100R groups, it was observed the X-ray caused mitotic delay, the irregularity of the time when mitotic peak appeared and the inhibiton of mitotic activity. In the control group, chromosome aerrations per cell was 0.030, whereas 0.147 in 5-AU treated group. In 5-AU+100R and 5-AU+200R groups, chromosome aberrations per cell were 0.583 and 0.669 respectively and the average chromosome aberrations per cell per R was 0.0035. 5-AU increased the frequency of labeled metaphases together with labeling intensity, and this is thought to be due to the accumulation of cells by 5-AU at S stage. On the contrary, X-ray decreased the labeling intensity and the frequency of labeled metaphases.

• Korean Journal of Community Nutrition
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• v.7 no.6
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• pp.749-761
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• 2002

This study investigated the anthropometric and biochemical indices, and the health and nutritional factors influencing the two indices among 194 middle-aged and elderly subjects (108 middle-aged and 86 elderly) residing in a medium sized city for more than 10 years. In the examination of their dietary habits, 8.3% of the middle-aged subjects and 14.0% of the elderly subjects had two meals a day, and more female subjects had two meals per day. Of the subjects who ate meals at regular times, 75.0% were middle-aged and 79.1% were elderly, and the degree of irregularity of meals was greater for female subjects. The study of the dietary behavior of the subjects indicated that 71.3% and 66.3% of the middle-aged and elderly, respectively responded that the amount of food in each meal was sufficient. The subjects ate alone comprised 19.7% of the middle-aged females and 31.5% of the elderly females. The prevalence of smoking among the subjects was 28.1% for the middle-aged, 18.8% for the elderly male and 7.4% for the elderly females. The percentage of the subjects who drank alcohol was 34.4% of the middle-aged males and 13.2% of the middle-aged females. Slightly less than half of the subjects exercised more than once a week, with the male subjects showing a higher rate than the female subjects. The average body mass indices (BMI) were 24.5 and 24.6 for the middle-aged male and female, respectively, and 22.6 and 24.0 for the elderly male and female, respectively. BMI assessment showed that underweight subjects (BMI ＜ 20) comprised 3.7% of the middle-aged, 14.0% of the elderly, and that 40.7% of the middle-aged and 24.4% of the elderly were overweight (25 ＜ BMI ＜ 30) , and 0.9% of the middle-aged and 1.2% of the elderly were classified as obese (BMI $\geq$ 30) . A waist/hip ratio (WHR) greater than 0.8 was found in 89.5% of the middle-aged females and 90.7% of the elderly females, showing high abdominal fat deposition in the majority of females. The average systolic blood pressure of females was 121.1 $\pm$ 17.1 mmHg for the middle-aged and 129.6 $\pm$ 21.3 mmHg for the elderly subjects. The systolic blood pressures showed a significantly difference between the two age groups. Those defined as anemic subjects based on hemoglobin values comprised 13.0% of the middled-aged group and 16.3% of the elderly group. There was a tendency for higher fasting glucose levels among the elderly subjects. An increase in total plasma cholesterol levels with age was shown. The female subjects had higher cholesterol levels than the males'The study of the correlation between the daily habits and health status showed that the amount of food eaten at each meal, the frequency of eating out, and the use of dietary supplements appeared to influence BMI, WHR, the plasma triglyceride and plasma cholesterol levels; omitting one meal had a positive correlation with the systolic blood pressure and plasma cholesterol. These results suggest that desirable dietary habits and concerns for health are contributing factors for maintaining good health, as indicated by normal blood lipid levels.

• Physical Therapy Korea
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• v.3 no.3
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• pp.67-81
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• 1996

This study was performed to assess the efficacy of high voltage pulsed galvanic current for the healing of wounds in rabbits. Skin wounds were created laterally on the flank of 12 domestic rabbits($3{\times}3cm$). The wounds of each group were treated with an intensity of 170 V at a frequency of 70 pulses per second, which was applied for 30 minutes a day for 10 days. The experimental groups were randomly assigned to either EXP I (n=3), EXP II(n=3), EXP III(n=3) or control(n=3). Each group was stimulated under the following conditions : 1) EXP I (Negative polarity), 2) EXP II (Change in polarity, negative electrode stimulation during the first 3 days and then positive electrode stimulation from 4 to 10 days), 3) EXP III(Positive polarity), 4) control(No stimulation). An active electrode was placed over the wound and a dispersive electrode on the buttock. The rate of wound closure was compared with the original wound size, evaluated by a tracing film in each measurement period. Finally, on the wound in each group, skin tissue was excised for histological evaluation after treatment for 10 days. The results obtained are as follows : 1) It was found that the control group did not show a complete remodeling of epitherial layer and had a chronic inflammatory response. Judging from the irregularity of intercellular space and the loose alignment of connective tissue, these findings show that wound healing was delayed. 2) EXP I showed a significant bactericidal effect, but a moderate response of vasodilation. The rate of wound closure was slower when compared with EXP II, III. 3) EXP II showed a complete remodeling of epitherial layer and a positive repair of connective tissue. Its rate of wound closure was best when compared with the others. 4) EXP III had a slower rate of wound closure than EXP II, but judging from the greater proliferation of collagen fibers and the dense alignment of connective tissue, this positive electrode was very effective in the formation of neo - connective tissue.

• Korean Journal of Community Nutrition
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• v.13 no.4
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• pp.489-498
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• 2008

This study was carried out to identify bone mineral density(BMD), body composition, lifestyle and dietary habits of young women by physical measurement and questionnaires. The study subjects, 190 young women living in Seoul, were divided into three age groups: $20{\sim}24$ years(93), $25{\sim}29$ years(44) and $30{\sim}39$ years(53). There was no significant difference in mean body muscle mass, protein, mineral, body fat and BMI among the three age groups. The rate of low weight(18%) in 20 years group was higher that of the 30 years(11.3%). The mean BMD and T-score were $0.44g/cm^2$ and -0.66. BMD and T-score of the forearm bone were significantly higher in the $30{\sim}39$ years group. But BMD and T-score of calcanues were not significantly different among the three age groups. The rate of normal, osteopenia and osteoporosis subjects by BMD were 60.5%, 38.4%, 1.1%, respectively. The rate of osteopenia in $20{\sim}24$ years group was significantly higher than the other age groups. The rate of meal irregularity was significantly higher in $20{\sim}24$ years group. The rate of women who walk and are exposed to sunlight more than 1hr per day were significantly higher in $20{\sim}24$ years group than the others. However, the score of food behaviors is significantly higher(bad) in $20{\sim}24$ years group than the others. The relationship between BMD and frequency of food intake showed significant differences in beans, broom, seaweed and rice wine. In conclusion, the risk rate of BMD was very high, 40% of the subjects, and the risk rate of BMD was higher in 20 years group than 30 years group, and the rate of low weight in 20 years group was higher than in 30 years group. The food habits and behaviors were not healthy enough. Therefore, nutrition education is needed for bone health.

• The Journal of Korean Physical Therapy
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• v.12 no.3
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• pp.319-329
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• 2000

The purpose of this study w8s to evaluate the effects of pulsed electromagnetic energy(Diapulse) and microcurrent on the wound healing in rabbits. 15 domestic rabbits were randomly assigned to the PRME(n=5). MC(n=5) and CON(n=91 group. Each rabbits were anesthetized with lidocaine HCL $2\%$. Skin wounds were created laterally on the back of IS domestic rabbits(33cm). From 24 hours after being injured, the rabbits of the PEME group were irradiated with an intensity of 3 at a 300 pulses per second, which were applied for 15 minutes every day during the 12 days. The MC group were stimulated with an intensity of $50{\mu}A$ at frequency of40 pulses per second, which were applied for 15 minutes every day during the 12 days. The CON group were not stimulated. The rabbits were sacrificed and the incised wound pans were processed appropriately for the light microscopic examination on the 3rd day, 6th day and 12th day before the beginning of wound treatment. The areas of wound were measured with metric graph paper. The results were as tallows. 1 The PRME and MC group compared with control group showed that wound closure rate increased on 6th, 12th day. 2. It was found that the CON group did not show a complete maturation and had a chronic inflammatory response. Judging from the irregularity of intercellular space and the loose alignment of connective tissue. these findings showed that wound healing was delayed. 3. It showed that inflammatory cells. fibroblasts and epithelial cells activity rapidly processed in the PEME group compared with the CON group. It was found that the PEMI; group showed a advanced remodeling of epithelial layer and a positive repair of connective tissue. 4. It showed that fibroblasts, epithelial cells and inflammatory cells activity rapidly processed in the MC group compared with the CON group. It was found that the MC group showed a improved remodeling of epithelial layer and a dense connective tissue.