• 대한치과기공학회지
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• 제39권4호
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• pp.263-273
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• 2017

Purpose: This study aimed to explore the relations between class distracting factors and class satisfaction of the dental technology students and then provide a primary data to help further related studies and develop educational programs with which instructors can efficiently manage their classroom. Methods: For this study we have conducted a survey started from the beginning of May 2017 to the end of June. The subjects of the survey were Dental Technology students of D-city, K-city, W-city, selected by random sampling method. The questionnaire was self-administrated and 437 valid results were chosen for our analysis among 450 distributed questionnaires. Results: The results of the research was as follows. Firstly, The overall average point of class distracting factors was 2.5 point. The environmental factors were the highest point as 2.59 and as for the subcategories tiredness and drowsiness was the highest point as 2.76. Secondly, The overall average point of class satisfaction turned out 3,88 point and compliance with class and attitude factors gained the highest point as 4.06. Of the subcategories strict roll checking was the highest point as 4.17. Thirdly, As for class distracting factors from general characteristics a statistical significance was shown as follows; 'instructor factor'(p<.01), 'learner factor'(p<.05), 'total class distracting factor'(p<.05) in the area of gender, 'environmental factor'(p<.001), 'total class distracting factor'(p<.01), 'learner factor'(p<.05), 'instructor factor'(p<.05) in the area of gender 'learner factor'(p<.001), 'instructor factor'(p<.001), 'environmental factor'(p<.001), 'total class distracting factor'(p<.01) in the area of class grade, 'environmental factor'(p<.05) in GPA. Fourthly, A statistical significance, a negative correlation (p<.01) were shown between class distracting factors and class satisfaction. Class distracting factor that especially affects the class satisfaction was instructor factor(p<.001) and the explanatory power of the model turned out 14.7%, which was statistically meaningful (p<.001). Conclusion : Results of this study reveal that instructor factor is the key to class satisfaction of the students. So it is crucial that the instructor faithfully prepare for the class to reinforce the students' learning. Additionally further studies should be followed with more subjects and newer perspectives to develop innovative teaching methodology.

• 수산해양교육연구
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• 제28권6호
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• pp.1882-1893
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• 2016

This study intended to look into the causal relations, in which a ski class conducted at a college is linked from college students' participation motivation to satisfaction and revisit. Among others, this study intended to boost the quality of the ski class conducted at a college with focus on the difference between the influences on satisfaction and revisit according to pre/post class participation. Further, the purpose of this study is to inquire into an ultimate basic plan required for winter sports development on the basis of the deduced results, through which this study drew the conclusion as follows: First, it was found that the influence relationship between class satisfaction before/after class was established in a joy seeking factor according to ski class participation motivation. Second, the daily routine deviation factor among the sub-factors of ski class participation motivation was found to have a positive effect on revisit before/after class while friendship promotion factor, health factor and physical strength factor were found to have an influence on revisit after class.

• Computers and Concrete
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• 제8권5호
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• pp.583-595
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• 2011

This paper studied the cement efficiency factor (k factor) of high calcium Class F fly ash. This k factor represents a unit of fly ash with efficiency equivalent to k unit of cement. The high calcium Class F fly ash was used to replace cement in concrete. The modified Bolomey's law with linear relationship was used for the analysis of the result of compressive strength, cement to water ratio (c/w) and fly ash to water ratio (f/w) by using the multi-linear regression to determine the k factor and other constants in the equations. The results of analysis were compared with the results from other researcher and showed that the k factor of high calcium Class F fly ash depends on the fineness of fly ash, replacement level and curing age. While the amount of CaO content in Class F fly ash not evident. Furthermore, necessary criteria and variables for the determination of the k factor including the use of the k factor in concrete mix design containing fly ash were proposed.

• 한국과학교육학회지
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• 제32권5호
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• pp.991-1006
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• 2012

본 연구에서는 고등학교 과학 교사의 수업 전문성 신장에 시사점을 찾고자 교사의 수업 구성에 영향을 주는 요인 분석틀을 개발하였으며, 수업 관찰과 면담에서 나타난 수업 구성 요인들을 확인하고, 이 요인들의 형태와 변화 유형을 분석하였다. 연구 결과, 교사의 수업 구성에 영향을 주는 요인으로는 크게 교사의 자발적 동기가 수업 구성에 작용하는 정적 동기 요인과 외부의 요구가 수업 구성에 작용하는 부적 동기 요인으로 분류할 수 있었다. 정적 동기 요인의 세부 요인으로는 특성 반영 요인, 체험적 요소 반영 요인, 사회 문화적 신념 요인, 대안적 구성 요인, 교과 내용적 신념 요인, 철학적 신념 요인으로 구분할 수 있었으며, 부적 동기 요인의 세부 요인으로는 내용적 인식차이 요인, 사회 문화적 요구 요인, 인지적 변화 요인, 정서적 차이 요인, 부정적 환경 요인, 과정적 보완요인 등으로 구분할 수 있었다. 개발된 수업 구성 요인 분석틀을 바탕으로 수업을 관찰하고 교사를 면담한 결과 정적 동기 요인, 부적 동기 요인들은 수업을 구성하는 단계, 수업을 진행하는 단계, 수업 후 단계에서 모두 나타났으며, 각 요인들은 상황에 따라 부적요인이 정적 요인으로, 정적 요인이 더 강화된 정적 요인 등으로 변화되는 것을 확인하였다. 부적 동기 요인들을 최소화하고 극복하는 것은 교사와 학생 간의 긍정적 상호 작용을 기대할 수 있으며, 수업에 대한 교사의 성취감을 증대시켜 교사의 수업 전문성 신장에 도움을 줄 수 있으며, 더 나아가 교실 수업의 어려움을 극복하는 데 시사점을 제공할 수 있다고 보여진다.

• 디지털융복합연구
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• 제14권9호
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• pp.579-588
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• 2016

본 연구는 교양체육수업의 재미요인, 수업만족과 운동지속행동의 관계를 규명하고자 하였다. 이를 위해 경기도에 속한 4개 대학 학생을 대상으로 300부의 설문지를 회수하여 연구 자료로 사용이 가능한 275부를 분석에 사용하였다. 분석을 위해 통계프로그램은 PASW 18.0 프로그램을 이용하여 각 요인에 대한 기술통계를 제시하였으며 요인추출 및 문항 내적 일관성 확인을 위해 탐색적 요인분석중 주성분분석과 베리맥스 회전 방식을 선택하였다. 신뢰도 분석에는 크론바 알파를 통해 신뢰도를 확인하였다. 교양체육수업의 재미요인, 수업만족과 운동지속행동 요인에 대해서는 다중회귀분석을 실시하여 관계를 규명하고자 하였으며, 다음과 같은 결론을 얻었다. 첫째, 교양체육수업의 재미요인 중 교수행동, 체육성적, 체육환경, 운동능력, 운동지속행동에 유의한 영향력을 주는 것으로 나타났다. 둘째, 교양체육수업의 수업만족 중 운동지속행동에 영향을 주는 것은 교수행동, 체육성적 요인이 유의한 영향력을 주는 것으로 나타났다.

• Journal of Power Electronics
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• 제12권3호
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• pp.429-438
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• 2012

This paper presents the use of a novel, single-stage high-power-factor electronic ballast with a symmetrical class-DE low-$d{\upsilon}$/$dt$ resonant rectifier as a power-factor corrector for fluorescent lamps. The power-factor correction is achieved by using a bridge rectifier to utilize the function of a symmetrical class-DE resonant rectifier. By employing this topology, the peak and ripple values of the input current are reduced, allowing for a reduced filter inductor volume of the EMI filter. Since the conduction angle of the bridge rectifier diode current was increased, a low-line current harmonic and a power factor near unity can be obtained. A prototype ballast, operating at an 84-kHz fixed frequency and a 220-$V_{rms}$, 50-Hz line input voltage, was utilized to drive a T8-36W fluorescent lamp. Experimental results are presented which verify the theoretical analysis.

• 통상정보연구
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• 제12권4호
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• pp.67-109
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• 2010

The theory of creative class has shown that the creative people are the key factor of success in regional economic growth. The creative people strengthen the economic competitiveness which is crucial to attract, cultivate and mobilize the resources of that region. In order to examine the theory of creative class for regional economic growth and firm productivity in Korea, this study uses the panel data of 492 Korean firms of the industrial complex producing electic and electronic manufactured goods. They are grouped into 10 industrial complexes among 16 metropolitan areas. Our findings demonstrate that creative class and 3Ts are related to the ratio of creative population density and the regional economic growth. Specifically the creative core class is of more significance to the regional economic growth than the creative professional class or the creative artist class. In our findings the panel analysis of random effects model shows that the talent index of 3Ts as well as the regional climates arc related to the individual firm's total factor productivity. This also reflects a conglomeration of the other regional climates statistically. On the other hand, the research and development expenditure of individual firms shows positive influence for each second consecutive year for the total factor productivity. Sales volume also contributes to the total factor productivity. In conclusion, we recommend that it is important to upgrade the level of creative climates by attracting the creative minds and R&D investment of the enterprises for regional economic growth and firm's total factor productivity.

• 한국환경과학회지
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• 제23권8호
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• pp.1507-1512
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• 2014

Recognition of Korean pre-service elementary school teachers concerning the factor for the environmental class was investigated and analyzed by the factorial analysis. Korean pre-service elementary school teachers are aware of the factor of 'participation in environment' as well as the factor of 'environmental knowledge' for the environmental class. Furthermore, they had a very positive attitude about the factor of 'participation in environment'.

• Journal of Power Electronics
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• 제3권3호
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• pp.175-184
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• 2003

In this paper, a new control scheme of Class-E inverter for reducing the crest factor of electronic ballasts for fluorescent lamps using Pulse-Frequency-Modulation (PFM) is Introduced The lifetime of the lamps is guaranteed by decreasing the lamp crest factor and also voltage stress of the switch is significantly decreased by a new scheme although conventional Class-E Inverter is used In this paper. The proposed PFM control scheme didn't use any auxiliary circuit. The proposed control strategy is executed by feeding back the Input voltage, and the zero-voltage-switching (ZVS) is ensured by maintaining constant turn-off time of the switch Therefore, the control principles of proposed method are explained in detail and its validity is verified through several simulations and experimental results.

• International journal of advanced smart convergence
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• 제4권1호
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• pp.64-70
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• 2015

This paper proposes fluorescent electronic ballast with high power factor and low line input current harmonics. The system performance can be improved by a charged pump circuit. Details of design and circuit operation are described. The proposed electronic ballast is modified from single-stage half bridge class D electronic ballast by adding capacitor parallel with each power switch and setting the circuit parameter to operate under class DE inverter condition. By using this proposed method the DC bus voltage can be reduced around by 50% compare with conventional class D inverter circuit. Because the power switches are operated at zero voltage switching condition and low dv/dt of class DE switching. The experimental results show that the proper frequency of the prototype is around 50 kHz with input power factor of 0.982, $THD_i$ 10.2% at full load and efficiency of more than 90%.