• Korean Journal of Optics and Photonics
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• v.2 no.3
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• pp.139-148
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• 1991

A fiber-optic magnetic sensor system for the detection of small ac magnetic field(200Hz-2 kHz) was constructed. Magnetic field sensing part was fabricated by bonding a section of optical fiber to amorphous metallic glass(2605SC) having large magnetostriction effect. And with the directional coupler, all fiber type Mach-Zehnder interferometer was constructed to measure the variation of the external magnetic field by translating it into the optical phase shift in the interferometer. The signal fading problem of the interferometer, which is due to random phase drifts originated from the environment, i.e., temperature fluctuation, vibrations, etc., was elliminated by feedback phase compensation. This allows the sensitivity to be maintained at the maximum by keeping the interferometer in quadrature phase condition. The frequency response of metallic glass was found to be nearly flat in the range of 90 Hz-2 kHz and dc bias field for the maximum ac response was 3.5 Oe. The interferometer output showed good linearity over the range $\pm$0.5 Oe. For 1 kHz ac magnetic field the scale factor S and the minimum detectable magnetic field were measured to be 8.0 rad/Oe and $3X10^{-6} Oe/\sqrt{Hz}$at 1 Hz detection bandwidth respectively.

• The Journal of Engineering Geology
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• v.28 no.4
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• pp.619-630
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• 2018

The purpose of this study is to investigate the existence of faults and intrusive rocks in the volcanic rock mass of Ulleung-do using magnetic anomalies. The magnetic survey data show that basaltic (mafic) rocks have high magnetic anomalies and that trachytic (felsic) rocks have low magnetic anomalies, implying that the anomaly distributions can be used to distinguish between different volcanic rock types that may be covered by regolith (such as alluvial and colluvial deposits) and other sedimentary layers. Our results show that basaltic rocks are not present within the Nari caldera. However, outside the caldera, the occurrence of high magnetic anomaly values of >$1,000{\gamma}$ is presumed to reflect the existence of basaltic craters or volcanic vents that formed prior to the eruption of the trachytic rocks. In particular, the area with anomaly values of >$1,000{\gamma}$ in the vicinity of Namyang-ri, southwest of Ulleung-do, is interpreted as having a high probability of hosting a crater and vent originating from mafic volcanism.

• Korean Journal of Culture and Social Issue
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• v.16 no.4
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• pp.423-445
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• 2010

Previous research have demonstrated that the external factors (ex., money, appearance) are more influential in Easterners' self-views and conditions for happiness than those of Westerners'. Based on these results, the current study examined whether 1) children and adolescents acquired these tendency as they grew up and 2) this tendency had relevance with social comparison. Total 954 students (260 elementary, 216 middle school, 260 high school and 218 college students) participated in the study. The results showed that elementary and middle school students regarded the internal factors (ex., thinking, feeling) as more important. But high school students considered the external factors as more important, and there was no difference in college students. Also, the results revealed that elementary and middle school students regarded the harmony of family and peace of mind as more important conditions for happiness. These results contrasted with preference for better educational backgrounds, better occupation, and money in high school and college students. In addition, age and social comparison tendency had positive relation with external self-concepts and negative relation with self-esteem. Especially, high school students showed strongest external self-concepts and social comparison tendency among four age groups. They also showed strongest preference for external conditions for happiness, but their self-esteem was the lowest. This might reflect fierce competition for college education in Korea, and the results of the current study have demonstrated that adolescents developed a tendency to prefer external factors to internal factors as they grew up in a competitive environment.

• Journal of Environmental Policy
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• v.6 no.4
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• pp.1-28
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• 2007

Because the result of environmental pollution of one state is not limited to the national border but spills over into neighboring countries or global environment either directly or indirectly, international discussions on environment are crucial in domestic environmental law and policy. International environmental law demands differential obligation between developed and developing countries in the principle of 'common but differentiated responsibility'. The common but differentiated responsibility is the principle that draws distinction between developed and developing countries about global environmental issues, while recognizing the common responsibility of environmental protection for all nations. Environmental technology transfer or financial support from developed countries to developing countries, for example, has been discussed. The problem is the status of Korea. Korea's international environmental policy will be different by the distinction of responsibility for international environmental protection according to the status of developed and developing countries. International communities have never established a clear standard distinguishing developed from developing countries in any international laws. The WTO entrusts each country to decide whether it is a developing country or not. In the international environmental law, the status of a country is determined by the ability to negotiate. The status of Korea, thus, cannot be fixed in general international law. Rather, the Korean government is able to choose its own status strategically, It can be a policy choice to insist that Korea's developing country so as to reduce the burden of international responsibility. But, considering an economic indicator and environmental pollution indicator at which Korea ranks about 10th, the reality of Korea is much closer to a developed country. Positive policies such as development of environment-friendly technologies and products should be preferred to defensive assertion of developing country.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.10 no.1
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• pp.50-63
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• 1999

Introduction：Test anxiety is a pervasive problem among high school students in Korea. While anxiety in test situations may actually facilitate the performance of some students, more often it is disruptive and leads to performance decrements. Over the past years, many child psychiatrists have become concerned with understanding the nature of test anxiety, but it is not clearly understood yet. In order to understand the nature of test anxiety, the relationship between test anxiety and depression, state anxiety, trait anxiety, temperament and family environment were examined. Methods：The Test Anxiety Inventory, Chidlren's Depression Inventory, State-Trait Anxiety Inventory, Temperamnet and Family Environment Scale Scale were administered to 576 high school students in Seoul. The relationships between test anxiety and other measures were tested using Pearson correlation coefficients and to test the causal relationship among the variables, regression analysis was performed. Results：The correlation coefficients between test anxiety and depression, state anxiety, trait anxiety, temperament and family environment scale were 0.42(p<0.01), 0.34(p<0.05), 0.38(p<0.05), 0.36(p<0.05) and -0.23(p<0.01), respectively. Regression analysis showed that only state and trait anxiety had direct causal relationship with test anxiety. Depression, temperament and family environment were indirecly related with test anxiety. Conclusions：This study indicates that the level of state and trait anxiety are directly related with test anxiety, and other variables such as temperament, family environment and depression are indirectly related with test anxiety. Thus, in order to develop the effective methods for treatment, these psychopathological characteristics should be kept in mind and the most important factors are the levels of state and trait anxiety.

• Korean Security Journal
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• no.21
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• pp.95-120
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• 2009

This study was designed to investigate the relationship between the stages of exercise behavior change and physical self-concept and self-efficacy of security employees in hotel casinos. The sampling was drawn from employees at 8 casinos which had more than 30 employees. Participants were selected by convenience sampling method and they completed questionnaires about Physical Self-Concept and Self- Efficacy by self-administration method under supervision of trained researchers SPSS 16.0 (Statistical Package for the Social Science) was used for data analysis in the present study. Reliability and validity were examined for the present study. The principle component factor analysis and varimax rotation were used for the present study. Eigen value 1.0 was the criterion for selecting factors. Chi-square (X) 2 test was utilized for measuring the difference in gender and types of job duties at the stages of exercise behavior change. One-way ANOVA was employed to examine the relationship between the stages of exercise behavior change as an independent variable and physical self-concept and self-efficacy as dependent variables. The Scheffe method was used to determine mean differences of groups as a follow-up test. Multiple regression analysis was utilized to test the difference of physical self-concept as dependent variable and self-efficacy as independent variable. To verify hypothesis for the study, a statistical significance level of $\alpha$=.05 was used. The results were as follow: first, there were differences found for gender and types of job responsibilities in the stages of exercise behavior change. Secondly, as security employees progressed through the stages of exercise behavior change, their physical self-concept and self-efficacy improved. Finally, physical activity and body fat had significant main effects on self-efficacy.

• Journal of Korea Society of Industrial Information Systems
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• v.25 no.2
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• pp.87-100
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• 2020

The purpose of this study is to examine whether some factors that influence the computerized accounting class in a university, namely the educational environment of the university, curriculum of the professor and his/her teaching methods, and the self-efficacy of the leaners manifest themselves in effective class satisfaction, class performance and class immersion which reflect these factors. As results, First, in the relationship between the class satisfaction, the professor, the students, and the educational environment of the university all had a significant influence. Second, in the relationship between the class performance, the professors and the students had a significant influence. However, class performance did not have a significant impact on the educational environment of the university and the program. Third, in the relationship between the factors of the classes and the classes immersion, which is one of the sub-elements of the learning performance, it was shown that the environment of the university and the students had a significant impact, while the program and the professor did not have an impact on the class immersion.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.2
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• pp.151-158
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• 2019

Objectives of this study were to identify the hotspot for displacement of the on-line water quality sensors, in order to detect illicit discharge of untreated wastewater. A total of twenty-six water quality parameters were measured in sewer networks of the industrial complex located in Daejeon city as a test-bed site of this study. For the water qualities measured on a daily basis by 2-hour interval, the self-organizing maps(SOMs), one of the artificial neural networks(ANNs), were applied to classify the catchments to the clusters in accordance with patterns of water qualities discharged, and to determine the hotspot for priority sensor allocation in the study. The results revealed that the catchments were classified into four clusters in terms of extent of water qualities, in which the grouping were validated by the Euclidean distance and Davies-Bouldin index. Of the on-line sensors, total organic carbon(TOC) sensor, selected to be suitable for organic pollutants monitoring, would be effective to be allocated in D and a part of E catchments. Pb sensor, of heavy metals, would be suitable to be displaced in A and a part of B catchments.

• Economic and Environmental Geology
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• v.22 no.2
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• pp.167-171
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• 1989

Palaeomagnetic studies accompany calculation and plotting of pole position. This paper explains three graphical methods for the determination of pole position and plotting problem. It also derives the numerical formula for pole calculation and explains the method how the pole plotted on the rear hemisphere can be transformed to the frontal hemisphere, which is not clarified elsewhere.

• Electronics and Telecommunications Trends
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• v.23 no.4
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• pp.10-18
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• 2008

본 고에서는 사용자의 자기 정보 통제권을 강화시키는 전자 ID 지갑 시스템을 기술한다. 전자 ID 지갑 시스템은 ID 정보 제공자로부터 ID 정보 소비자로 유통되는 사용자의 정보를 사용자가 직접 제어할 수 있는 기능을 제공한다. 또한 전자 ID 지갑 시스템은 사용자가 가입한 사이트, 사용자의 크리덴셜 및 사용자의 데이터 공유 정보 등을 사용자에게 모두 카드-기반의 인터페이스로 제공하여 사용자에게 편리함과 일관성을 제공한다. 전자 ID 지갑 시스템은 현재의 웹 환경뿐만 아니라 사용자의 참여와 공유가 더욱 더 중요해지는 웹 2.0 환경에 적합한 사용자 중심 ID 관리 시스템이다.