• Geophysics and Geophysical Exploration
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• v.8 no.1
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• pp.26-33
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• 2005

Inversion of multi-mode surface-wave phase velocity for shallow engineering site investigation has received much attention in recent years. A sensitivity analysis and inversion of both synthetic and field data demonstrates the greater effectiveness of this method over employing the fundamental mode alone. Perturbation of thickness and shear-wave velocity parameters in multi-modal Rayleigh wave phase velocities revealed that the sensitivities of higher modes: (a) concentrate in different frequency bands, and (b) are greater than the fundamental mode for deeper parameters. These observations suggest that multi-mode phase velocity inversion can provide better parameter discrimination and imaging of deep structure, especially with a velocity reversal, than can inversion of fundamental mode data alone. An inversion of the theoretical phase velocities in a model with a low velocity layer at 20 m depth can only image the soft layer when the first higher mode is incorporated. This is especially important when the lowest measurable frequency is only 6 Hz. Field tests were conducted at sites surveyed by borehole and PS logging. At the first site, an array microtremor survey, often used for deep geological surveying in Japan, was used to survey the soil down to 35 m depth. At the second site, linear multichannel spreads with a sledgehammer source were recorded, for an investigation down to 12 m depth. The f-k power spectrum method was applied for dispersion analysis, and velocities up to the second higher mode were observed in each test. The multi-mode inversion results agree well with PS logs, but models estimated from the fundamental mode alone show f large underestimation of the depth to shallow soft layers below artificial fill.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.5
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• pp.349-361
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• 2021

With the development of technology and the advancement of weather forecasting models and prediction methods, higher performance weather forecasting software has been developed, and more precise and accurate weather forecasting is possible by performing software using supercomputers. In this paper, the weather forecast model used by six major countries is investigated and its characteristics are analyzed, and the Korea Meteorological Administration currently uses it in collaboration with the UK Meteorological Administration since 2012 and explains the GloSea However, the existing GloSea was conducted only on the Meteorological Administration supercomputer, making it difficult for various researchers to perform detailed research by specialized field. Therefore, this paper aims to establish a standard experimental environment in which the low-resolution version based on GloSea6 currently used in Korea can be used in local systems and test it to present the localization of low-resolution GloSea6 that can be performed in the laboratory environment. In other words, in this paper, the local portability of low-resolution Globe6 is verified by establishing a basic architecture consisting of a user terminal-calculation server-repository server and performing execution tests of the software.

• Journal of Korea Trade
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• v.23 no.6
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• pp.33-51
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• 2019

Purpose - The purpose of this study is to provide practical implications for Korean companies searching for new market opportunities. From the experimental analysis, the impact of country image on product-country image and purchase intention of Korean products are measured. In addition, this study disaggregates the impacts of country image and product-country image and purchase intention among ethnic groups in South Africa for searching further useful implications. Design/methodology - To examine South African consumers' country image and product-country image towards Korean products, data were collected between June and July 2019 through an online questionnaire, and 335 questionnaires were used for analysis. Firstly, the multivariate analysis was conducted to examine the general tendency of South African consumers' perceptions of country image to Korea, product-country image, and purchase intention among three ethnic group consumers. Then in order to verify the country image model and hypotheses of the study, we analyzed the structural models for each of the three ethnic groups and compared the sizes of the path coefficients for each groups. To compare the difference of path coefficients across ethnic groups, configural invariance, metric invariance, and scalar invariance tests were conducted sequentially. Findings - In the black and white ethnic groups, the country image had a statistically significant impact on product-country image, but it did not affect the purchase intention to Korean products. The product-country image showed a statistically significant impact on the purchase intention to Korean products in both ethnic group. However, in the coloured ethnic group consumer, the country image had a significant effect on the product-country image, but it did not affect the purchase intention of Korean products. In addition, the product-country image did not have a significant influence on the purchase intention of coloured ethnic group consumers unlike black and white ethnic group consumers. The results of this study suggest that even though differences in terms of the impact of CoI on PCI and PI were investigated for the sample of white, coloured, and black respondents, the groups seemed to respond in a reasonably comparable manner. Originality/value - South Africa occupies more than 20% of Africa's total GDP in sub-Saharan Africa and is a hub for Southern African logistics as a hub for Korean companies to enter Africa. However, it is rare to find a study focused on the determinants of consumer behavior in South Africa. In particular, this study disaggregates the impacts of country image and product-country image on consumer behavior across ethnic groups in South Africa. Therefore, this study could provide practical implications for Korean firms which desire to diversify their export markets and pioneer future markets.

• Journal of Life Science
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• v.31 no.7
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• pp.631-640
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• 2021

Houttuynia cordata Thunberg has been studied for a variety of pharmacological actions in traditional oriental medicine. In this study, we investigated the effects of Houttuynia cordata ethanol extract (HCE) on benign prostatic hyperplasia (BPH) models induced by castration and testosterone propionate (TP) injection. Thirty rats were divided into six groups. One group was used as a normal control, and the other groups were castrated and had intraperitoneal injections of TP for 14 days to induce BPH. A positive control group was given daily doses of finasteride (5 mg/kg) to the BPH model. Rats administered HCE (0.5, 1 or 2 mg/kg) instead of finasteride were compared with controls as experimental groups. There was no statistical significance in terms of prostate weight based on 100 g of body weight. The concentrations of 5-α reductase and dehydroxytestosteronre (DHT) were determined via ELISA tests, and there was a significant decrease in all experimental groups. The 0.5 mg/kg HCE group had the lowest level of 5-α reductase, and the 2 mg/kg HCE group had the lowest level of DHT. In the histopathological observation of prostates, the control and the 2 mg/kg HCE groups had normal cell shapes and no swelling. However, in the negative control group and the 1 mg/kg HCE group, the cells were swollen, and the gap between the cells was narrowed. In particular, in the 0.5 mg/kg HCE group, some cells were bursting. Therefore, the administration of more than 2 mg/kg of HCE is suitable to protect against BPH.

• International Area Studies Review
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• v.12 no.3
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• pp.153-169
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• 2008

This paper examines the recently empirical test for the two types of endogenous growth models, which one is more fitted to real data. We adopt the non-stationary panel data methodologies for seeking empirical implication by using productivity and R&D data in the OECD over the past two decades. The Empirical tests show that there is a robust relationship Total Factor Productivity and R&D variables implied by semi-endogenous growth model. The relationship suggested by fully endogenous growth theory, however, is sensitive to R&D variables. Therefore, the estimation results provide empirical evidence in favour of endogenous growth theory of R&D expenditure role for sustaining economic growth. The sustained Total Factor Productivity, however, is maintained by more increasing R&D inputs for overcoming diminishing return to R&D efforts.

• Korean Public Health Research
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• v.44 no.4
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• pp.99-109
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• 2018

Objective : Health literacy (HL) is, defined as "the degree to which individuals have the capacity to obtain, process, and understand basic health information and services needed to make appropriate health decisions." Being old is one of the main risk factors with limited health literacy. This study aims to adapt Chew's health literacy scale into the Korean language and validate the scale for the use of the elderly. Methods : Data were drawn from the '2016 Seoul Survey on Elderly Health and Functional Assessment, which includes a total of 725 people aged 60 to 79. The sample was randomly divided into two groups for reliability and validity tests of the modified Chew's scale of 8 items. The Korean version of the questionnaire was developed by group translation, expert reviews, and forward-backward translation. Exploratory and confirmatory factor analyses were conducted to assess and validate the factor structure of the scale. Results : Results suggest the two-factor structure ("Understanding" and "Applying" of HL) with 8 items. Exploratory factor analyses of the first sample (n=400) revealed that the internal reliability of the scale was high (Cronbach's ${\alpha}=.904$). Principal axis factoring extracted two factors ("Understanding" and "Applying" of HL) and explained 78.3% of total variance (KMO=.872, Bartlett's ${\chi}^2=2431.3$, df=28, p<.001). Confirmatory factor analysis of the second sample (n=325) was performed and the two-factor model was supported (GFI=.960, CFI=.979, TLI=.969, RMSEA=0.075). Conclusions : This study provides evidence for adequate criterion and validity of the health literacy scale for the community dwelling elderly in Korea.

• Journal of vocational education research
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• v.33 no.3
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• pp.105-125
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• 2014

The purposes of this study are to develop the standardized tests of career preparation behavior of career preparation behavior for college students. For these, the 'Career Preparation Behavior Scale for College Students' which was developed in 2011 was reviewed and revised. After 609 students were involved and analyzed for the pretest, 1,244 subjects were collected by taking into account gender, grade, major, and location of colleges for developing a standardized test. The Career Preparation Behavior Scale consisted of 3 subareas and 30 items: 11 items for learning area, 12 items for counseling and information collecting area, 7 items for employment action area. The levels of reliabilities, construct validity, discriminant validity, and the concurrent validity were relatively high. Also, the suitability index of the structural model was analyzed to check the structural significance. The degree of career reparation behavior among norm groups was increased in general according to the grades. Scores of students majoring in humanities and social sciences received significantly high scores compared with those of majoring in science and technology or in art and music. But the levels of satisfaction on career preparation behavior were no difference according to gender, grade, and major. 'The Standardized Career Preparation Behavior Scale for College Students' would be used for conducting career education or programs for college students in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.732-740
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• 2019

Evaporative humidification using a humidifying element is widely used for humidification of a building or a data center. The performance of a humidifying element is commonly expressed as humidification efficiency, which is used independent of air temperature, humidity and water temperature. In this study, a series of tests were conducted at two air conditions (data center and commercial building) using two different humidifying elements (cellulose/PET and Glasdek) changing the frontal air velocity and water temperature. Results showed that the measured humidification efficiency was dependent on the air condition and water temperature. In fact, even dehumidification occurred at the inlet of the humidifying element at the air condition of commercial building. The reason was due to the inlet water temperature, which was lower than the dew point air temperature. As the difference between the inlet water and the dew point air temperature increased, the humidification efficiency decreased. This suggest that proper thermal model should account for the inlet region, where the amount of moisture transfer may be different from the other part of the humidification element. A simple analysis on the thermal performance of the cellulose/PET humidification element showed that the Sherwood number was adequately predicted, whereas the friction factor was ovepredicted, probably due to the simplification of the channel geometry and the neglection of the water film on the element surface.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.326-331
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• 2018

Evaporative humidification using a humidifying element is used widely for the humidification of a building or a data center. The performance of a humidifying element is commonly expressed as the humidification efficiency, which is assumed to be independent of the air temperature or humidity. To verify this assumption, a series of tests were conducted under two air conditions - data center ($25^{\circ}C$ DBT, $15^{\circ}C$ WBT) and commercial building ($35^{\circ}C$ DBT, $21^{\circ}C$ WBT) - using humidifying elements made from cellulose/PET and changing the frontal air velocity from 1.0 m/s to 4.5 m/s. Three samples having a 100 mm, 200 mm, or 300 mm depth were tested. The results showed that the humidification efficiency is dependent on the air condition. Indeed, even dehumidification occurred at the inlet of the humidifying element at the air condition of commercial building. This suggests that a proper thermal model should account for the inlet area, where the amount of moisture transfer may be different from the other part of the humidification element. As the depth of the element increased from 100 mm to 200 mm, the humidification efficiency increased by 29%. With further increases to 300 mm, it increased by 42%. On the other hand, the pressure drop also increased by 47% and 86%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.8-14
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• 2019

Bird-strike is one of the most important design factors for safety in the aviation industry. Bird-strikes have been the cause of significant damage to aircraft and rotorcraft structures and the loss of life. This study used DYTRAN software to simulate the transient response of an Euler-Lagrangian composite helicopter blade that has been impacted by a bird. The Arbitrary Lagrangian Eulerian (ALE) method and a suitable equation of state were applied to model the bird. ALE was applied to the bird-strike analysis due to the large difference between the properties of the blade and bird. The debris of the bird was assumed to be a fluid and applied as Euler elements after the collision. Through the analysis of bird impacts, the leading-edge of the rotor blade (50.8 mm) was used to identify a positive margin of 1.18 based on the TSAI-FILL criteria. The results are assessed to be sufficiently reliable and may be evaluated to replace tests with various analysis conditions. The structural stability of the rotor blade could be assessed by applying various load conditions and different modeling methods in the future.