• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.10
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• pp.1343-1350
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• 2000

The evolutionary structure of tip vortices has been investigated with a two-dimensional LDV system for a plain and a slotted blade, respectively. To analyze the effect of slots which bypasses a part of main stream into the tip face, velocity profiles, vortex sizes, their displacements and turbulence intensities during one revolution of the rotor were measured by the phase averaging process. For the comparison of circumferential velocity components of the plain blade and the slotted blade, the peak values of the slotted blade were lower than those of the plain blade, and axial velocity components of the slotted blade were considerably larger than those of the plain blade. The slotted rotor blade enlarged the core size and made the vortex delayed compared with those of the plain blade at the same wake ages. Turbulence profiles had peaks inside the core radii and decayed gradually in the radial direction of vortex coordinate. Also, using a quasi 3-D LDV measurement technique the budget of turbulence kinetic energy was analyzed in radial direction of the vortex core.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2012.06a
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• pp.155-156
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• 2012

In the modern age, as man's demand of energy is continuously grew, tidal becomes one of the sustainable energy sources that have been investigating thoroughly recently. Tidal turbine has proved high potential as a future power-generating device. To effectively capture tidal energy on site, a group of tidal turbines should be used and positioned in some formation with proper size and space so that energy can be absorbed from multiple point. Thus, the turbines together with the flow filed becomes a huge domain, a tidal farm. So, it becomes more convenient if a whole turbine farm is simulated by means of actuator discs since the time and cost for analysis can be reduced. This paper aims to evaluate the operating performance (power efficiency and energy restoration rate), mutual influence (for different longitudinal and lateral spaces), the influence of velocity profiles, turbulence intensity and the far wake characteristic of tidal turbines operating in farm formation. The results of this study help contributing to the present development of tidal turbine as the future potential energy conversion machinery.

• Journal of Digital Contents Society
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• v.10 no.3
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• pp.447-452
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• 2009

In information age, sharing about the information and various techniques to control other computers which are connected in network started to appear. One of these techniques is remote control system. However, conventional remote control systems have had a lot of inconvenience to use because of limited functions. For example, it always has to connect to the electricity supply to operate the server program. Also, one-to-one remote control is only possible by one's permission. In order to solve the problems of the conventional remote control system's limited functions, this paper implements the system which applies the WOL(Wake On Lan) function to be possible remote power control to multi client computers by one server computer connected to a lot of client computers not one-to-one.

• Journal of Environmental Science International
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• v.12 no.1
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• pp.1-14
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• 2003

This research attempts to describe and explain the development of Korean environmental movement. It finds that the emergence of Korean environmental movement was constrained by the authoritarian nature of Korean politics. In 1970s, environmental movements were primitive and were not organized ones. With the wake of democratization in the 1980s, Korean environmental movement began to get some momentum. And in the 1990s, environmental movement to save clean water has achieved some success in certain areas. However, the emphasis on the growth of local economy in the age of local autonomy system has brought heavy degradation of local environment. The coming of the phenomena of Globalization and Cyber-Age has brought positive effects on Korean environmental movement.

• The Korean Journal of Food & Health Convergence
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• v.8 no.3
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• pp.1-9
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• 2022

Purpose-Meat plays an important role in the Chinese daily diet, however, due to the spread of COVID-19, food supply and safety have become a major concern. The safety and health features of chilled fresh meat have attracted the attention of consumers. To study consumers' purchasing behavior and willingness to pay for chilled meat under the influence of the epidemic. Research methodology- The data were obtained by questionnaire survey, major issues include consumers' meat consumption habits in the wake of the COVID-19 and their awareness of meat product quality labels. In addition, the gender, age, family income, and other basic personal information of the interviewees were also counted. Based on the binary Logit regression method, we study consumers' purchasing behavior and willingness to pay for chilled meat under different demographic characteristics. Results-The results showed that brand and quality certification are important factors influencing purchases. In addition, the presence of children under the age of 12 in the household and the level of income and education also influence consumers' purchase intention of the chilled fresh meat. However, mart promotions and city ratings can significantly lower consumers' propensity to buy the chilled fresh meat. Apart from this, such factors as gender, age, and living conditions have no significant influence on consumers' purchase of chilled fresh meat.

• Sleep Medicine and Psychophysiology
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• v.13 no.1
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• pp.15-21
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• 2006

Introduction: The objective of the present study was to investigate bedtime, rise time and time-in-bed of Korean college students, separately on weekday and on weekend and to compare them. In addition, this study also aimed to evaluate the influence of gender, age and grade on the above sleep parmeters in Korean college students. Methods: Information regarding bedtime and rise time, separately on weekday and on weekend, of Korean college students were obtained by self-administered questionnaire. Questionnaires of 1,825 students (1,416 females and 409 males, age 18-30；mean age $21.1{\pm}2.2$) were used for statistical analyses. Results: Korean college students retired to bed 50 minutes later (00：49 on weekday；01：40 on weekend；t=39.67, p<0.001), rose 1 hour 58 minutes later (07：52 on weekday；09：50 on weekend；t=39.46, p<0.001), and slept 1 hour 8 minutes longer (t=13.33, p<0.001) on weekend. Compared to male students, female students had earlier rise time (t=8.96, p<0.01；t=3.89, p<0.01) and earlier bedtime both on weekday and weekend (t=7.10, p<0.01；t=6.04, p<0.01), and shorter time-in-bed on weekday (t=1.99, p<0.01). In addition, rise time delay and time-in-bed increase on weekend were more prominent in female students than in male students (t=3.41, p<0.01; t=3.68, p<0.01). Grade was correlated with bedtime and rise time on weekday (${\beta}=0.1022$, p<0.01；${\beta}=0.1009$, p<0.01), bedtime and time-in-bed on weekend (${\beta}=0.1096$, p<0.01；${\beta}=-0.0990$, p<0.01), and differences between week-day and weekend of the rise time and the time-in-bed (${\beta}=-0.0906$, p<0.01；${\beta}=-0.1115$, p=0.02). Conclusions: In this study, Korean college students had earlier bedtime/rise time and shorter time-in-bed on weekday than on weekend. These findings suggest that weekday sleep-wake schedule of Korean college students may be advanced relative to their biological sleep-wake cycle and that this discrepancy may be associated with weekday sleep deprivation. In addition, differences of sleep patterns between weekday and weekend were more prominent in female students and students with lower grade. Therefore, discrepancy between weekday sleep-wake schedule and biological sleep-wake cycle, as well as weekday sleep deprivation, might be more serious in female or lower-grade students.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.2
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• pp.171-183
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• 2013

We examined breakfast patterns and preferences in 420 elementary school students (216 boys, 206 girls) in the Chung-nam area. About thirty percent of the subjects had breakfast irregularly. The main reasons for skipping breakfast were having a 'poor appetite' and being 'busy'. The person who prepared breakfast was the 'mother' in both groups. Subjects were satisfied with 'Korean style' menu but dissatisfied with 'rice porridge-style'. Multiple regression analysis indicated that the 'frequency of having breakfast' was positively related to the subject's 'frequency of having breakfast with their mother'. On the other hand, the frequency of having breakfast was negatively related to feeling obligated to have breakfast. The multiple regression analysis also indicated that a Korean style 'breakfast preference' was positively related to the mother's age and negatively related to their 'wake-up time'. A 'breakfast preference for bread and milk' was positively related to 'bed time' and negatively related to the 'age of the father'. Our results will provide critical information for the nutritional education of elementary school students.

• Journal of Fashion Business
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• v.16 no.1
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• pp.83-102
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• 2012

The instant trend of mobile functionality in the digital age is performing a mediating role of promoting the hybrid tendency in fashion and cosmetics industry. Consumers' needs, which are getting complex and diversified along with development in scientific technology, are requiring product of technology equipped with multi-tasking function in the whole industry. The social and cultural factors, which are shown in cosmetics due to the instant trend of mobile functionality, came to be known on the basis of a ground for classification caused by a change in nomadic lifestyle and by the advance in scientific technology. The irst, The mobile functionality, which is being developed in fashion in the digital age, was indicated to be types such as mobility, one-off, and unity. Second, Even the types of mobile functionality, which are also being developed in make-up and cosmetics in digital age, were indicated to be mobility, one-off, and unity. Third, The trend caused by mobile functionality in fashion was consistent with a type in mobile functionality, which is being developed in cosmetics, thereby having been indicated to be the same type. This implies that there is the same type through independent trend in each sphere even while fashion and cosmetics organically function in the middle of the whole frame, which expresses a human being's external beauty, and implies that even the cosmetics are influenced by fashion. Swift-type beauty product, which is thrown away within one week lengthily and after being used once, are being launched diversely. This quick product can be said to be product that best reflected the characteristic of digital age. However, at this point of time that fast fashion and instant cosmetics, which are thrown away in the wake of being worn easily, are overflowing, the clothing and product with perfection, which has philosophy and thinking of being put more devotion, exert more value and are felt to be necessary.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.20 no.3
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• pp.146-151
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• 2009

Objectives : We conducted this study to investigate the relationship between sleep duration and body mass index (BMI), in Korean children. Methods : We performed a cross-sectional analysis of data collected on 3,639 boys and girls (aged 7-12) in Daegu, Korea. The data included each child's age, sex, weight, height, extracurricular activities, bedtime, wake-up time, sleep latency, total sleep duration, parents' occupations, and parents' educational levels. The relationship between sleep duration and each variable was examined via analysis of variance (ANOVA). Results : The analysis showed an association between short sleep duration and high BMI. Boys showed a graded inverse relationship between sleep duration and BMI. However, there was no significant corresponding result for girls. In the total sample, hours of computer use, time when the computer was turned off, time when the television was turned off, mother's bedtime, and hours of extracurricular activity were associated with longer sleep duration. No association was found between sleep duration and hours of watching television, child's wake-up time, or educational level of the parents. Conclusion : The results of this study show an inverse relationship between a child's sleep duration and BMI；thus, children with shorter sleep duration tend to have higher BMIs.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.3
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• pp.303-309
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• 2022

The goal of this research is to examine how credit (loan) can help rural households in Tra Vinh province create jobs in the wake of the COVID-19 outbreak in Vietnam over the last two years. The authors performed a direct survey, using a questionnaire, with 300 customers who had loan records at the Tra Vinh VBSP branch under the loan programs. From January to April 2021, jobs will be available at 07 transaction offices in districts and cities (Cau Ngang; Duyen Hai, Tieu Can, Cang Long, Tra Vinh City, Chau Thanh, Tra Cu). Using the multivariate regression method, the research has found 12 factors affecting the ability to access the employment loan program: Age, Educational Level, Occupation of households, Income, Household land area, Asset, Loan, Interest rates, Loan procedures, Loan purpose, Credit relations. From the above research results, the authors have proposed solutions to improve the ability to access credit to create jobs for each subject group at Viet Nam Bank for Social Policies, Tra Vinh Province in the future.