• Journal of Technologic Dentistry
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• v.39 no.4
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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.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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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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• v.8 no.5
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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.

• Journal of The Korean Association For Science Education
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• v.32 no.5
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• pp.991-1006
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• 2012

The purpose of this research is to find factors that affect high school science teachers' class compositions. In this research, we developed the class composing factor analysis framework and we observed teachers' class to figure out the class composing factors. The results from this research were as follows: First, the class composing factor was classified with 'positive motive factor' and 'negative motive factor'. It is the positive motive factor that teachers' voluntary motives operate to teacher for class compositions. It is the negative motive factor that outer demands operate to teacher for class compositions. Second, both positive and negative motive factors were shown in all the steps, which included preparing a class, progressing a class, and after a class. Also, according to the circumstances, each factor changed. Minimizing and overcoming negative motive factors will lead to positive interaction between the teacher and students. It will also increase a teachers' achievements in class and maximize the effectiveness of class. Therefore, it is expected that this will be a great help for teachers to enhance their teaching professionalism.

• Journal of Digital Convergence
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• v.14 no.9
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• pp.579-588
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• 2016

This study is to identify the relationship between cultural physical education class of enjoyment factor, class satisfaction, and exercise continuation behavior. For this purpose, 275 out of 300 copies of survey aimed at students in four universities located in Gyeong-gi province were used. PAWS 18.0 program was used for analysis to present descriptive statistics. Principal component analysis and rotation of Max Berry were used among exploratory factor analysis to check factor extraction and internal consistency. Cronbach's alpha was used for checking reliability. Multiple regression analysis was used to clarify the relationship between enjoyment factor, class satisfaction, and exercise continuation behavior of cultural physical education. These are the following conclusions. First, instructional behavior, grade in physical education, environment, and exercise ability among the enjoyment factors in cultural physical education class have a significant effect on persistence of exercise. Second, instructional behavior and grade in physical education are the factors of class satisfaction and the have a significant effect on persistence of exercise.

• Journal of Power Electronics
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• v.12 no.3
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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.

• International Commerce and Information Review
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• v.12 no.4
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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.

• Journal of Environmental Science International
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• v.23 no.8
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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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• v.3 no.3
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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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• v.4 no.1
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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%.