• Journal of applied mathematics & informatics
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• v.26 no.5_6
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• pp.1057-1069
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• 2008

We consider singularly perturbed Boundary Value Problems (BVPs) for third and fourth order Ordinary Differential Equations(ODEs) of convection-diffusion type with discontinuous source term and a small positive parameter multiplying the highest derivative. Because of the type of Boundary Conditions(BCs) imposed on these equations these problems can be transformed into weakly coupled systems. In this system, the first equation does not have the small parameter but the second contains it. In this paper a computational method named as 'An asymptotic finite element method' for solving these systems is presented. In this method we first find an zero order asymptotic approximation to the solution and then the system is decoupled by replacing the first component of the solution by this approximation in the second equation. Then the second equation is independently solved by a fitted mesh Finite Element Method (FEM). Numerical experiments support our theoritical results.

• Journal of Families and Better Life
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• v.14 no.4
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• pp.71-84
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• 1996

The purposes of this study were to classify the family types based on the intra system dynamics and to examine sociodemographic backgrounds and the life satisfaction of these families. The data were collected by means of questionnaire distributed to a stratified sample of 544 housewives in Seoul who lived with housbands and children. The questionnaire included FACES II and III Communication Scale managerial behavior scale and life satisfaction Scale. Frequency percentile mean correlation factor analysis cluster analysis one-way ANOVA with scheffe test and chi-square test were used to analyze the data. This study had resulted in four major findings. The first was that highly positive relationships were found among four intra system dynamics elements. The first was that highly positive relationships were found among four intra system dynamics elements. The second finding was that families were clustered by four types named personal-oriented enervated dynamic and managerial-orien ed family. The third finding was that the four types of family were influenced by education level and job of husbands and family income. The last one was that the differences in life satisfaction were found among four types of family. The housewives of dynamic family type showed the highest level of satisfaction whereas the lowest level of life satisfaction was found among housewives of enervated family type. The recommendations for future esearch and better ways to educate and counsel families were suggested.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.3
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• pp.103-112
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• 2020

Purpose : This study aims to investigate social welfare and students' image of social workers and determine the relevance of these factors to the academic system, gender, and their motivations when selecting a major. Methods : For this study, social welfare students from two two-year colleges and two four-year universities were randomly selected, and 320 students from social welfare departments who understood and agreed to participate in the research took the survey. The data analysis of this study was conducted using SPSS 23.0. Results : The Social Welfare Department students' perception of a social worker's image was shown to be positive. In the social worker image based on academic background, the first grade was found to be more positive than the second, third, and fourth grades. The professional image was more positive than the traditional, social, and vocational images. The gender-based social worker image showed that females were more positive than males. Females were more positive for the professional image, and males were more positive for the traditional image. Regarding the image of social workers based on students' motivation when choosing their major, it was found that volunteer jobs were more positive in terms of traditional images, social images through recommendations, and professional images with aptitude and interest. Conclusion : In sum, most of the students in the social welfare departments had a positive perception of the social worker position. They had a more positive image at the time of admission. Finally, students who entered the school with an expert awareness of social welfare were more positive.

• Korean Management Science Review
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• v.32 no.4
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• pp.57-67
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• 2015

It is a familiar Wall Street adage that "It takes volume to make prices move." Numerous researches have found the positive correlation between trading volume and price changes. Recent studies have documented that informed traders have strong influences on stock market prices through their trading with distinctive information power. Ever since 1992 capital market liberalization in Korea, it is said that foreign investors make consistent profits with their superior information and analytical skills. This study aims at whether we can make a profitable trading strategy by using the foreign investors' trading information. We analyse the relation between the KOSPI index returns and the foreign investors trading volume using GARCH models and VAR models. This study suggests the profitable trading strategies based on the documented relation between the foreign investors' trading volume and KOSPI index returns. We simulate the trading system with the real stock market data. The data include the daily KOSPI index returns and foreign investors' trading volume for 2001~2013. We estimate the GARCH and VAR models using 2001~2011 data and simulate the suggested trading system with the remaining out-of-sample data. Empirical results are as follows. First, we found the significant positive relation between the KOSPI index returns and contemporaneous foreign investors' trading volume. Second, we also found the positive relation between the KOSPI index returns and lagged foreign investors' trading volume. But the relation showed no statistical significance. Third, our suggested trading system showed better trading performance than B&H strategy, especially trading system 2. Our results provide good information for uninformed traders in the Korean stock market.

• The Journal of Fisheries Business Administration
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• v.42 no.2
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• pp.113-130
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• 2011

The laver has been cultivated long time ago by Korea and Japan. Korean Laver Industry has been influenced by Japan on the many factors since 20th. Nevertheless now the both country showed widening disparities across the aspect of total Laver Industry each other. The development steps of Korea and Japan Laver Industry have been advanced differently. That is, we can keep the Laver Industry development steps of both countries separate by 4 steps. But insignificant of every step against both countries has been dissimilar. We can separate from 4 steps in Korea, 1 step is origin period from beginning of laver cultivation to 1961. Next step is First Development period from 1962 to 1978. This period come out production increase from about 10,000 tons early 1960 to 50,000 tons late 1970. Next step is Second Development period from 1979 to 2000. This period come out eminent production increase from about 50,000 tons early 1980 to 200,000 tons late 1990. Next step is Stabilization period from 2001 to now. This period come out production control the size of its production and enlargement of Laver Export. We can also separate from 4 steps in Japan, 1 step is origin period from beginning of laver cultivation to 1944. Next step is Development period from 1945 to 1975. This period come out production increase from about 4 billion sheets early 1960 to 8.5 billion sheets 1975. Next step is Peak period from 1976 to 1982. This period come out sustainable production peak by 6~8 billion sheets and high price. Next step is Decline period from 1983 to now. This period come out production control the size of its production and sustainable price down. These differences showed out facing problems of Korean and Japanese Laver Industry differently. In case of Korea, the facing problems show out 3. First is structural problem, for example, trouble between original laver producer and the finished producer by dry laver products. Second is Insufficiency of Plants Protection System. Third is low quality of Laver. In case of Japan, the facing problems also show out 3. First is sustainable decrease of laver consumption. Second is change of mind against laver, for example, the change of the propensity to consume, and decrease of brand power. Third is Influence of global system. The difference of development steps of Korea and Japan Laver Industry show out 2 point of view to us. First we need consider positive strategy against laver production system of enlargement. Second, we need consider separate strategy against high quality laver and low quality laver.

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1101-1107
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• 2017

In this paper, a robust and fast grid synchronization method of a three-phase power converter is proposed. The amplitude and phase information of grid voltages are essential for power converters to be properly connected into the utility. The phase-lock-loop in synchronous reference frame has been widely adopted for the three-phase converter system since it shows a satisfactory performance under balanced grid voltages. However, power converters often operate under abnormal grid conditions, i.e. unbalanced by grid faults and frequency variations, and thus a proper active and reactive power control cannot be guaranteed. The proposed method adopts a second order generalized integrator in synchronous reference frame to detect positive sequence components under unbalanced grid voltages. The proposed method has a fast and robust performance due to its higher gain and frequency adaptive capability. Simulation and experimental results show the verification of the proposed synchronization algorithm and the effectiveness to detect positive sequence voltage.

• Korea Journal of Hospital Management
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• v.29 no.1
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• pp.56-63
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• 2024

Purposes: This study aims to analyze the correlation with the current status of the medical resident application rate, physician's income, and non-benefit rates of majors in each specialty subject and to suggest implications. Methodology: First, it analyzes the correlation between the medical resident application rate by specialty subject and the income of physicians. Second, it analyzes the correlation between the income of specialists and the non-benefit rate for each specialty subject at the clinic level. Findings: First, a significant positive correlation was found between the medical resident application rate and the average physician's income for each specialty subject (r=.718, p<.01). Second, a significant positive correlation was observed between physician income at the practitioner level by medical specialty and the non-benefit rate (r=.726, p<.01). Practical Implications: In this study, the correlation between medical resident application rate by specialty subject and physician's income, non-payment and physician's income was confirmed. Choosing a department that is less risky and can earn higher income is a natural phenomenon, but it is necessary to adjust the physicians crowding phenomenon to a specific specialty subject at the government level to maintain the medical system.

• Journal of Korea Society of Digital Industry and Information Management
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• v.17 no.4
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• pp.121-132
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• 2021

This study analyzed the effect of the extracurricular activity management system on user satisfaction. For this purpose, the effects of content, navigation, screen frame, design, interaction, and error handling factors on user satisfaction were analyzed. A survey was conducted on 321 students of K University located in Chungcheongbuk-do, and the research results based on the survey contents are as follows. First, content, navigation, screen frame, interactivity, and error handling, which are major elements of the extracurricular activity management system, showed statistically significant results. Second, interactivity and error handling were found to have the greatest influence on the factors affecting user satisfaction of the extracurricular activity management system. In this study, it was found that the interaction of the whole system including contents is important for continuous improvement of the extracurricular activity management system, and that it has a positive effect on user satisfaction when prompt error handling is possible.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.550-551
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• 2013

Large-area RF-driven ion source is being developed at Germany for the heating and current drive of ITER plasmas. Negative hydrogen (deuterium) ion sources are major components of neutral beam injection systems in future large-scale fusion experiments such as ITER and DEMO. RF ion sources for the production of positive hydrogen ions have been successfully developed at IPP (Max-Planck- Institute for Plasma Physics, Garching) for ASDEX-U and W7-AS neutral beam injection (NBI) systems. In recent, the first NBI system (NBI-1) has been developed successfully for the KSTAR. The first and second long-pulse ion sources (LPIS-1 and LPIS-2) of NBI-1 system consist of a magnetic bucket plasma generator with multi-pole cusp fields, filament heating structure, and a set of tetrode accelerators with circular apertures. There is a development plan of large-area RF ion source at KAERI to extract the positive ions, which can be used for the second NBI (NBI-2) system of KSTAR, and to extract the negative ions for future fusion devices such as ITER and K-DEMO. The large-area RF ion source consists of a driver region, including a helical antenna (6-turn copper tube with an outer diameter of 6 mm) and a discharge chamber (ceramic and/or quartz tubes with an inner diameter of 200 mm, a height of 150 mm, and a thickness of 8 mm), and an expansion region (magnetic bucket of prototype LPIS in the KAERI). RF power can be transferred up to 10 kW with a fixed frequency of 2 MHz through a matching circuit (auto- and manual-matching apparatus). Argon gas is commonly injected to the initial ignition of RF plasma discharge, and then hydrogen gas instead of argon gas is finally injected for the RF plasma sustainment. The uniformities of plasma density and electron temperature at the lowest area of expansion region (a distance of 300 mm from the driver region) are measured by using two electrostatic probes in the directions of short- and long-dimension of expansion region.

• Journal of Korea Society of Industrial Information Systems
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• v.16 no.5
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• pp.151-161
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• 2011

Social Network Service is a web-based service that allows the people to construct relationship among users with same interest and supports various activities such as managing personal relations and sharing information or contents. Based on the IS Post-Acceptance model and Success Model, this study examines factors influencing the continuance intention in the SNS. Questionnaires are collected from 275 students who are using the SNS. The results are following: first, the perceived usefulness and satisfaction have positive effect on the continuance intention. Second, the perceived usefulness, confirmation, system quality and information quality have positive effect on the satisfaction. Third, the confirmation has positive effect on the perceived usefulness. Fourth, the system quality and information quality have positive effect on the confirmation. Fifth, the satisfaction is the strongest predictor of the continuance intention and the perceived usefulness is the strongest predictor of the satisfaction.