• Journal of Korean society of Dental Hygiene
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• v.16 no.1
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• pp.1-9
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• 2016

Objectives: The purpose of the study was to identify the oral care status and periodontal disease of middle aged daibetic patients in Korea. Methods: The primitive data were taken from 238 diabetic people in the 5th Korea National Health and Nutrition Examination Survey(KNHANES) in 2010 - 2012. The variables included general profiles(gender, age, occupied area, education, and smoking), oral care status(brushing time, brushing time, use of oral hygienic supplies, availability of oral hygienic supplies, oral examination, and recognition of oral health state), and diabetes management(morbidity period, treatment, education, and glycosylated hemoglobin levels). Results: Most of the subjects took gargling more than twice a day and it accounted for 73.5%. Oral hygienic supply users accounted for 24.8%, and most of them used floss brush. Oral examination was done in 19.3% of the respondents and 55.0% thought that their oral health status were very poor. The prevalence rate of the periodontal diseases was 46.6%. Female tended to have a higher rate of periodontal disease than the male. Oral hygienic supply users had lower rate of periodntal disease than those who did not use. Those who had poor subjective oral health status had higher prevalence rate of periodontal disease than those who did not. Conclusions: Periodontal disease is closely related to good oral care of middle aged diabetic patients. It is necessary to develop the program for the prevention of the periodontal disease for the diabetic patients.

• Journal of Power Electronics
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• v.19 no.5
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• pp.1122-1132
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• 2019

In this paper, aiming at high-voltage applications, transformer windings schemes of multiple-output two-transistor flyback converters are investigated, which are mainly based on the stray capacitances effect. First, based on a transformer model including equivalent stray capacitors, the operational principle of the converter is presented, and the main influence of its stay capacitors is determined. Second, the windings structures of the transformer are analyzed and designed based on the stray capacitances effect. Third, the windings arrangements of the transformer are analyzed and designed through a coupling analysis of the secondary windings and a stray capacitance analysis between the primary and secondary windings. Finally, the analysis and design conclusions are verified by experimental results obtained from a 60W laboratory prototype of a multiple-output two-transistor flyback converter.

• Current Optics and Photonics
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• v.8 no.3
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• pp.225-229
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• 2024

This paper introduces a rapid measurement technique for the stress-optic coefficient, using terahertz time-domain spectroscopy. First we propose a design combining a four-point bending device with a scanning stage to streamline the loading process. Then we detail the measurement principle and outline the signal-processing algorithm. The experiments are carried out on Al₂O₃, a representative ceramic material. The experimental data reveal that the refractive index of Al₂O₃ exhibits a linear decrease with increasing stress. This work supplies an efficient method for stress measurement rooted in the stress-optic effect.

• 대한예방의학회:학술대회논문집
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• 1999.10a
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• pp.69-70
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• 1999

• Korean Journal of Health Education and Promotion
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• v.19 no.2
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• pp.57-72
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• 2002

Students spend most of their time in school. Schools have the possibility of unanticipated accidents, however, and the rate of accidents in schools is increasing. The purpose of this study were to understand the accidents that arise in schools as well as the school safety management system and by analyzing affects that school safety management system has on accidents in schools, to come lip with a preventive plan. 906 high school sophomore students attending in Seoul were surveyed 1Tom November 12th to 23rd 2001. The results were following: 1. Students surveyed comprised of the following: Male 48.9%, Female 51.1% Public Schools 32.6%, Private Schools 67.4% Boys Schools 48.9%, Girls Schools 51.1% 2. In the past year, male students had more accidents(p〈.05) in school. 3. In examining students safety management control, 94.0% said that, there is an infirmary, there is a clear distinction between the playing fields and pathways(74.8%), and the chemicals in the labs are kept in a safe manner(77.2%). The above items were generally well maintained. However, the following recorded low scores. There are warning signs in hazardous places and facilities(30.5%), There is guiding principle to examine the safeness on a regular basis(24.9%), and There are slogans and posters preventing accidents(40.3%). 4. In examining the facilities of the schools that were surveyed, the majority answered, yes to the following. There are hazardous facilities or materials at school(62.9%), There are sharp edges in educational supplies and equipment(59.8%), There are nails or other components that are sticking out of desks and chairs(75.9%), There are slippery spots in the corridors and classrooms(69.3%), There are stones, scrap metal, broken glass, and trash on the playing fields(66.6%). Furthermore, the students surveyed said, yes to the following although in low percentages. The amount of sand on the playing fields is sufficient(49.1%), The soccer and basket goal posts are fastened (53.7%), There are safety bars on the windows of classrooms and corridors (27.4%), There are safety mats on the entrance to restrooms preventing slips (14.2%), The stairs have slip protection measures(49.1%). 5. In analyzing the affect that the school safety management system has on accidents in school, schools that had slogans and posters preventing accidents had a 50% less chance of accidents(p〈.05), schools with chemicals and equipment in the labs that were safely maintained had an 80% less probability of accidents(p〈.0l), and the schools that had sharp edges in the educational supplies and equipment had an 80% greater chance of accidents(p〈.01).

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.461-464
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• 2008

Plan of Human Resource Development is essential to strategically promote poor domestic fire protection industry and as a consequent to grow it to a high value added service industry. To foster fire protection industry, any reform will be needed to for a smooth supplies of work force by training customized high class work force. Consequently, In this study, We will investigate and analyze the status and problems of current domestic fire protection industry so that We can suggest the direction for a way to improve these.

• School Mathematics
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• v.4 no.3
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• pp.347-360
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• 2002

This study analyzed the mathematical and didactical contexts of the Euclid's proof about Pythagorean theorem and compared with the teaching methods about Pythagorean theorem in school mathematics. Euclid's proof about Pythagorean theorem which does not use the algebraic methods provide students with the spatial intuition and the geometric thinking in school mathematics. Furthermore, it relates to various mathematical concepts including the cosine rule, the rotation, and the transfor-mation which preserve the area, and so forth. Visual demonstrations can help students analyze and explain mathematical relationship. Compared with Euclid's proof, Algebraic proof about Pythagorean theorem is very simple and it supplies the typical example which can give the relationship between algebraic and geometric representation. However since it does not include various spatial contexts, it forbid many students to understand Pythagorean theorem intuitively. Since both approaches have positive and negative aspects, reciprocal complementary role is required in pedagogical aspects.

• Journal of Electrical Engineering and Technology
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• v.11 no.1
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• pp.55-64
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• 2016

The development of high-speed rail (HSR) has had a major impact on the power supply grid. Based on the monitored waveforms of HSR, a pattern recognition approach is proposed for the first time in this paper to identify the operating conditions. To reduce the data dimensions for monitored waveforms, the principal component analysis (PCA) algorithm was used to extract the characteristics and their waveforms from the monitored waveforms data. The dynamic time wrapping (DTW) algorithm was then used to identify the operating conditions of the HSR. Cases studies show that the proposed approach is effective and feasible, and that it is possible to identify the real-time operating conditions based on the monitored waveforms.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.263-264
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• 2006

A new method for the electrostatic suspension of disk-shaped objects is proposed which is based on a time-optimal control scheme and deploys only high-voltage power supplies that can deliver do voltages of positive and/or negative polarity. This method possesses the unique feature that no high-voltage amplifiers are needed which leads to a remarkable system simplification and objects can be suspended stably even in vacuum environment. Using this scheme, an Aluminium disk employed in a 3.5-inch HDD was suspended stably at an airgap of 0.3mm.

• Journal of Korean Home Economics Education Association
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• v.9 no.2
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• pp.161-174
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• 1997

The purpose of this study is to investigate the effects of self-concept, reference group, consumer education, and materialism on the propensity for conspicuous consumption of adolescents. The data used in this study were collected through questionnaires on 604 adolescents living in Cheju City. The data were analyzed by using SPSS PC(sup)+ program. The propensity for conspicuous consumption of adolescents differed significantly according to their age and allowance, and sex. The propensity for conspicuous consumption of the middle school students was higher than that of the high school students. The propensity for conspicuous consumption of boys was higher than of girl’s. The propensity for conspicuous consumption of the adolscents was influenced by materialism and the reference group. According to the results of the multiple regression analysis, the most influential factor was materialism and reference group. In clothing materialism was the most influential factor and the reference group was the second influential factor. But In shoes, bag, and school supplies the reference group was the most influential factor and materialism was the second influential factor.