• Journal of Electrical Engineering and Technology
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• v.11 no.1
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• pp.125-134
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• 2016

We propose an efficient high voltage level shifter for a high side Buck converter driving a light-emitting diode (LED) lamp. The proposed circuit is comprised of a low voltage pulse width modulation (PWM) signal driver, a coupling capacitor, a resistor, and a diode. The proposed method uses a property of a PWM signal. The property is that the signal repeatedly transits between a low and high level at a certain frequency. A low voltage PWM signal is boosted to a high voltage PWM signal through a coupling capacitor using the property of the PWM signal, and the boosted high voltage PWM signal drives a p-channel metal oxide semiconductor (PMOS) transistor on the high side Buck converter. Experimental results show that the proposed level shifter boosts a low voltage (0 to 20 V) PWM signal at 125 kHz to a high voltage (370 to 380 V) PWM signal with a duty ratio of up to 0.9941.

• Phonetics and Speech Sciences
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• v.3 no.3
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• pp.35-47
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• 2011

The purpose of this study is to examine the influence of Chinese high and level vs. rising tone on the pitch pattern of corresponding Sino-Korean words delivered by Chinese learners of Korean and to examine the aspects how these two tones of corresponding Chinese words affect the pitch patterns of Sino-Korean words. Scope of this research is limited to the Chinese learners of Korean, especially when they pronounce same-form-same-meaning Sino-Korean words. In this study, Chinese learners pronounced both Chinese words and corresponding Sino-Korean words. By using the software learners' pitch pattern were recorded, analyzed, and compared with the tone of corresponding Chinese words. Experimental results showed that Sino-Korean words were affected by Chinese 'high and level tone - high and level tone', 'high and level tone - rising tone', 'high and level tone - falling-rising tone', 'high and level tone - falling tone' and 'rising tone - falling tone' when they started with lenis sounds. On the other hand when Sino-Korean words started with aspirated sounds they were affected by Chinese 'rising tone - high and level tone', 'rising tone - rising tone', 'rising tone - falling-rising tone', 'rising tone - falling tone'. In conclusion, the Chinese learners' pitch patterns of Sino-Korean words are affected by both Chinese high and level & rising tone, especially when Sino-Korean words started with lenis sounds they were more affected by Chinese high and level tone, on the other hand Chinese rising tone influence Sino-Korean words more when they were started with aspirated sounds.

• Journal of Electrical Engineering and information Science
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• v.1 no.2
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• pp.109-118
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• 1996

This paper deals with a new multi-level high voltage source inverter with GTO Thyristors. Recently, a multi-level approach seems to be the best suited for implementing high voltage conversion systems because it leads to harmonic reduction and deals with safe high power conversion systems independent of the dynamic switching characteristics of each power semiconductor device. A conventional multi-level inverter has some problems; voltage unbalance between DC-link capacitors and larger blocking voltage across the inner switching devices. To solve these problems, the novel multi-level inverter structure is proposed.

• Educational Technology International
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• v.19 no.1
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• pp.93-122
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• 2018

It is crucial to understand the characteristics of learner questioning due to the effects it has on learning. This study focuses on the effects of middle school students questioning on their academic achievement in an online inquiry learning environment. A survey of 827 middle school students was conducted; the students took part in an online math and science program offered by a center for the gifted. Throughout the survey, learner questioning was analyzed, and its correlation with academic achievement was investigated. An analysis was based on questioning categories of a low- and high-level questions from previous studies. Through the survey, it was found that the number of learner questions asked in the online environment was small, but the number of low- and high-level questions were almost equal. Secondly, the higher the academic achievement level of the student, the higher the possibility they would ask either low- or high-level questions. Lastly the group of students in both low- and high-levels of questioning earned the highest average scores on formative evaluations and inquiry tasks. This indicates that regardless of the level of questions, the act of questioning itself is highly related to the academic achievement. However, in the case of advanced learning projects, the quality of questioning and high-level questioning affected the academic achievement of students. Based on these results, implications for the encouragement of learner questioning and support for asking high-level question are suggested.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.7
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• pp.791-798
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• 1988

Films of Cr, Cu, and Al were deposited by the evaporation technique at the high vacuum level-high evaporation rate and the low vacuum level-low evaporation rate. We measured sheet resistance and light transmittance, and observed microstructure and diffraction pattern by TEM, and investigated oxygen content in thin film by AES. We discussed the relations among microstructure, sheet resistance, and light transmittance with AES data. We found that the films deposited at the high vacuum level-high evaporation rate have small oxygen content in thin film comparing to the films deposited at the low vacuum level-low vacuum level-low evaporation rate, and that the films having crystalline structure and larger grain size were formed in the case of the high vacuum level-high evaporation rate and they showed lower sheet resistance and lower light transmittance.

• Journal of the Korean Home Economics Association
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• v.8 no.1
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• pp.198-215
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• 1970

The basic purpose of this study is to explore the household economic effects on home administration. The major goals of home administration is to promote mental and physical welfare of the family members. In order to realize mental and physical welfare, the stability and satisfaction is needed. And to promote stability and satisfaction, the efficiency must be accomplished and the efforts is required. So the four variables to measure home administration situation are as follows. 1) The degree of the stability 2) The degree of the efficiency 3) The degree of the efforts 4) The degree of the satisfaction. The factor of Household economic level is the size of the family's money income. Although size of income is not the bases for either standard of living or Socioeconomic status, it is closely related to both. To solve this problem. Some hypotheses are specified as follows. Hypotheses I The degree of the stability is different among the groups by income level. The group which is high income level will be more stable than low income level. Hypothesis II The degree of the efficiencies different among the groups by income level. The group which is high income level will be more efficient than low income level. Hypothesis III The degree of the efforts is different among the groups by income level. The group which is high income level will more effort than low income level. Hypothesis IV The degree of the satisfaction is different among the groups by income level. The group which is high income level will feel more satisfaction than low income level. In order to test those hypotheses random selection of 190 subjects from the four girls high schools in Seoul was made, and the parents of the students reported their home administration situation. The results of this study show that; 1) the group which is high income level revealed more stability than low income level. The differences of each group are revealed very significant. 2) The differences of the degree of the efficiency among the groups are unsignificant. 3) the group which is high income level revealed more effort than low income level. The differences of each group are revealed significant. 4) The group which is high income level revealed more satisfaction than low income level. The differences of each group are particularly significant. So the conclusion can be drawn from this study. Every group by income level revealed significant differences in home administration. So the household economy greatly effects on home administration.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.4
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• pp.337-343
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• 2015

The multi-level inverters are highly efficient for high-power and medium-voltage AC driving applications, such as high-speed railway systems and renewable energy resources, because such inverters generate lower total harmonic distortion (THD) and electromagnetic interface (EMI). Lower switching stress occurs on switching devices compared with conventional two-level inverters. Depending on the multi-level inverter topology, the required components and number of switching devices are different, influencing the overall efficiency. Comparative studies of multi-level inverters based on loss analysis and output characteristic are necessary to apply multi-level inverters in high-power AC conversion systems. This paper proposes a theoretical loss analysis method based on piecewise linearization of characteristic curves of power semiconductor devices as well as loss analysis and output performance comparison of five-level neutral-point clamped, flying capacitor inverters, and high-level cascaded H-bridge multi-level inverters.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.1
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• pp.99-111
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• 2016

This paper presents an integrated fault diagnosis algorithm for driving motor of In-wheel independent drive electric vehicle. Especially, this paper proposes a method that integrated the high level fault diagnosis and the low level fault diagnosis in order to improve a robustness and performance of the fault diagnosis system. The high level fault diagnosis is performed using the vehicle dynamics analysis and the low level fault diagnosis is carried using the motor system analysis. The validity of the high level fault diagnosis algorithms was verified through $Carsim^{(R)}$ and MATLAB/$Simulink^{(R)}$ cosimulation and the low level fault diagnosis's validity was shown by applying it to a MATLAB/$Simulink^{(R)}$ interior permanent magnet synchronous motor control system. Finally, this paper presents a fault diagnosis strategy by combining the high level fault diagnosis and the low level fault diagnosis.

• Journal of Korea Entertainment Industry Association
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• v.15 no.4
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• pp.309-315
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• 2021

Purpose of this study is to analyze the correlation between the level of smartphone overdependence and depression among the high school student. Study subjects were 50 high school student. The assessment of the level of smartphone overdependence was used by the smartphone overdependence scale for adolescents and the assessment of the level of depression was used by Korean ver. of patient health questionnaire-9. As the results, the positive correlation was showed between the level of smartphone overdependence and depression and the statistically significant difference was showed. It was found that the higher the level of smartphone overdependence among high school students, the higher the level of depression. The smartphone overdependence among high school students could contribute to increase the level of depression. Thus, based on these results of this study, it is necessary to consider to reduce the level of smartphone overdependence and depression among high school students and subsequent studies should be conducted to clarify the casual relationship and influences of the level of smartphone overdependence and depression among high school students.

• Journal of the Korean Society of School Health
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• v.4 no.2
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• pp.119-135
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• 1991

The study was designed to gain necessary basic data order to grasp health knowledge, attitude, practice level of middle and high school students and to analyse th problem and to point out the method of improvement in the field of school health education. The survery was carried out through this reporter's interview for 2,400 students who attend to ten schools in Young Nam area during the period of a month from 25 the June to 25th July 1989. The result of this study can be summaried as follows. 1. The total number of answers on the question was 2,346. As for general characteristics the percent of female middle school students was 60.6% and the percent of male students was 77.7%, 45.9% of high school students was evening school students. 52.9% of middle school students and 42.3% of high school students were borne in rural area. 2. The percentage of unknown and misunderstanding for Epidemic Hepatitis infection was 46.3% of middle school students and 29.6% of high school students. 3. The percentage of unknown and misunderstanding for Epidemic Hemorrhage fever infection was 85.6% of middle school students and 66.9% of high school students. 4. The percentage of right knowledge for AIDS infection was 66.0% of middle school students and 90.4% of high school students. 5. The percentage of right knowledge for Typhoid infection was 47.8% of middle school students and 69.4% of high school students. 6. The percentage of unknown and misunderstanding for Tuberculosis infection was 71.6% of middle school students and 62.2% of high school students. 7. As for personal hygiene, the percentage of toothbrushing after every meal was high level : 44.2% of middle school students and 42.0% of high school students. 8. 60.9% of middle school students take a bath twice a week, 49.2% oh high school students take a bath a week. Times of bath of middle school students was higher than that of high school students. 9.The percentage of washing hand after using toilet was 42.1% of middle school students and 35.1% of high school students. 49.0% of middle school students and 55.1% of high school students wash hand sometimes after using toilet. 10. The percentage of change of underwear twice a week was 57.6% of middle school students and 49.8% of high school students. 11. The percentage of habit of unbalanced diet was 30.% of middle school students and 27.6% of high school students. 50.8% of middle school students and 51.7% of high school students have balanced diet. 12. Index of health practice of personal hygiene can be summarized as follows. A. A case of middle school students. 1) The percentage of health practice index in male and female was 49.6% and 48.1% respectively. Index of female students was higher than that of male students. 2) As for parent's occupation, public servants and company emplyee was upper level. Farming was low level. 3) As for income level, middle, level with 56.5% was highest in high income level and low level with 27.4% was highest in low income level. B. A case of high school students. 1) Middle level of health practice index was 46.0% of male students, upper and low level was 32.4% and 28.0% of female students respectively. 2) Middle level of health practice index was high in farming and company employee and upper level was high in commerce and service, low level with 60.0% was high in unemployed. 3) Upper practice index 35.7% appears in the rich and low practice index 38.3% appears in the poor. 13. Average points of Health practice about personal hygiene were as follows. (Full marks at 4). A. A case of middle school. Female (1.87 point) was higher than male (1.26 point). Night time (2.03 point) was higher than day time (1.66 point) and middle or small cities (2.17 point) are high than any other places. As for parent's occupation, students whose parents are company clerk get high marks (2.32) and ten students whose parent's job are service get next high marks (2.20). B. A case of high school. Female (1.53 point) was higher than male (1.22 point), as parents educational level were higher the point were higher, and as income level was higher, the points of health practice (1.78) were higher, and as for parents occupation, service get highest point (1.93) and commerce get next high point (1.86) public servant get low point (1.66). 14. The percentage of experience in smoking was 11.9% of middle school students and 60.9% of high school students. 15. The percentage of experience in inhalation of bond and administrating LSD was 4.3% of male middle school students, 8.4% of female middle school students, 6.9% of male high school students and 4.2% of female high school students. The knowledge level of communicable disease infection are very low in middle and high school students and practice level of personal hygiene are also very low. As a whole we can evaluate that middle and high school students are low level of health knowledge and practice. In conclusion, we must consider preparation for school health education program through establishing of health subjects in the carriculum, and securing of health education teachers and using materials and media program of health education. It is very important to establish macroscopic policy and strategy for public health education and to get people have right knowledge and practice for health.