• Journal of the Korean School Mathematics Society
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• v.2 no.1
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• pp.67-77
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• 1999

The purpose of this study was to design models of CAI programs for the graphing of quadratic functions. In order to achieve this aim, I researched the relationship between mathematics educations computer programing, and theoretical approaches of CAI. The CAI program, which was developed based on my research was then positively applied to the mathematics education class in a middle school. First of all, I selected two classes -An experimental class and a comparative class. The experimental class was taught using the CAI program and the comparative class was taught by conventional methods of instruction. The results of this study are as follows: 1. The class taught by using the CAI program scored higher academic achievement than the class taught by conventional methods of instruction. 2. The analysis of the two classes' academic scores shows that the instruction using CAI program is more effective than that by conventional methods in improving students' academic achievement. The followings are suggestion for developing CAI programs and students' understanding through this study. 1. Non computer specialists will require a few months to develope an effect CAI program. Thus, development of easier, more clearly defined and flexible models must be constructed. 2. Teachers should be eager to use pre-existing models to motivate their students irregardless of their own development of programs. 3. School should provide computer rooms with a perfect net work in proportion to class size. 4. CAI programs can make students understand faster and more directly than blackboard examples. However, inconsideration of mathematical characteristics, arithmetic by hand is more effective for the students' memory retention. Computers is an effective tool of instruction. But it is most effective when used in conjunction with other methods that complement its use.

• English Language & Literature Teaching
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• v.12 no.4
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• pp.159-183
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• 2006

The purpose of this study is to investigate Korean primary school English teachers' beliefs on self-directed teaching and learning for facilitating student's self-directed learning. A survey was conducted, using 315 primary school teachers as participants. According to different school areas, sex, English teaching careers, and types of English teaching like classroom teachers or English specialist teachers, beliefs on teachers' self-directed teaching were studied based on class planning, class process, utilization of human resources, development and utilization of teaching materials and class evaluation. The results of this study are as follows: first, differences were not shown except class planning according to teachers from different school areas. Second, sex and beliefs of teachers' self-directed teaching had nothing in common. Third, differences were shown in class planning and class process, according to English teaching careers. Finally, according to types of English teaching, differences were shown in class process and development and utilization of teaching materials. The study suggests that it is necessary to conduct other studies for observing primary English classrooms focusing on teacher's self-directed decision-making.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.2
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• pp.68-71
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• 2006

A class-E power amplifier is designed using 0.25$\mu$m standard CNMOS technology at 900MHz and the reliability characteristics are studied with the load network. The reliability characteristics is improved when a finite DC-feed inductor is used instead of RF choke. At the one you halt, the PAE(Power Added Efficiency) decreases from 58.0$\%$ to 35.7$\%$ and output power decreases from 120mW to 74mW in power amplifier using RF choke. However, when a finite DC-feed inductor is used with load the PAE decreases from 58.5$\%$ to 54.8$\%$ and output power decreases from 121mW to 112mW. From the simulated results, the class-E power amplifier with a finite DC-feed inductor shows superior reliability characteristics compared to rower amplifier using RF choke inductor.

• Journal of the Korea Society of Computer and Information
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• v.21 no.9
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• pp.165-176
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• 2016

This study developed the learning ability-based smart education program. The effectiveness of the developed materials was investigated using the quantitative-qualitative mixed method, and the process and results of the investigation are as follows. The quantitative investigation was conducted using the non-equivalent pretest-posttest design, in which the smart education method was applied to the experimental group, while the conventional education method was applied to the control group to analyze students' creative problem-solving potential, task concentration, and the variables required for the learning activity. The results showed significantly higher performance in the experimental group over the control group. Regarding data collection in the qualitative investigation, an analysis of the class from the instructor and class consultation logs from the class analyst were collected; the comments on the experience of each class period were collected from students. The results of the analysis of the data suggest that the perception of smart education improved for the instructor, class analyst, and learners as the course progressed.

• Journal of Information Technology Applications and Management
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• v.29 no.1
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• pp.29-45
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• 2022

The Fourth Industrial Revolution era requires people to have the ability of integrated thinking, critics, sensitivity, and creativity in an integrated manner. Therefore, teaching methods are expected to become more suitable for the trend. In this belief, current teacher-leading education method should move to students' self motivating one and consist of programs in which students voluntarily involve. In this reason, this study suggests FPBL educational method model that is combines project-based learning with flipped learning by analysing preceding research and digital painting tool class was designed by applying it. As a result of applying the designed class model to the class, all of the class satisfaction, effectiveness, and interaction were evaluated positively. Problems such as limitations of project classes due to non-face-to-face classes, large amount of learning before class, and reduced concentration during class were found. Therefore, when the FPBL class model is conducted non-face-to-face, it will be necessary to further strengthen the role of the instructor, provide lecture videos summarizing the core contents, and improve concentration by providing active participation and fun using various digital tools. The result of the study looks significant by confirming the possibility of applying FPBL model not only in design education but also other educational settings.

• Korean Journal of Child Studies
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• v.2
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• pp.67-82
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• 1981

The present study was intended to investigate ecological characteristics of poverty areas in Seoul from the perspectives of children's development. More specifically, the objectives of the study are to examine environmental ecology of the poverty areas and it's potential psycho-social development of children. Three poverty areas and 150 children currently living in the are as were sampled ; 70 children from middle class families and 88 from lower class respectively. Focal ecological aspects surveyed family environment, outdoor play ground and facilities, and village housing structures. Psycho-social dimension's development dealt with in the study included children's perceptions of parental child rearing practices and role taking, and children's future perception and perspectives. Data were collected through interviews and observations using structured formats. Following results were obtained from the data : 1. Children from the poverty families showed a higher tendency to have working mothers than those from middle class. 2. The rate of having single room is higher for children from middle class by two times than from lower class. 3. Children from lower class tended to have less favorable perceptions of attitudes tote and their own families than those from middle class. 4. The likelihood of showing discrepancy in vocational choice for children between parents and children is higher for children from lower class and those from middle class. 5. Children from lower class tended to allot more time in playing with peers than those from middle class. 6. The size of outdoor play ground are inadequately poor both for middle and lower class children. The inadequateness is particularly severe for the lower class children, showing that the size and facilities of playing ground available for the child from lower class is less than half compared with those of the children from middle class.

• MALSORI
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• no.60
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• pp.145-164
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• 2006

This paper proposes class histogram equalization (CHEQ) to compensate noisy acoustic features for robust speech recognition. CHEQ aims to compensate for the acoustic mismatch between training and test speech recognition environments as well as to reduce the limitations of the conventional histogram equalization (HEQ). In contrast to HEQ, CHEQ adopts multiple class-specific distribution functions for training and test environments and equalizes the features by using their class-specific training and test distributions. According to the class-information extraction methods, CHEQ is further classified into two forms such as hard-CHEQ based on vector quantization and soft-CHEQ using the Gaussian mixture model. Experiments on the Aurora 2 database confirmed the effectiveness of CHEQ by producing a relative word error reduction of 61.17% over the baseline met-cepstral features and that of 19.62% over the conventional HEQ.

• Journal of Preventive Medicine and Public Health
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• v.35 no.1
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• pp.76-82
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• 2002

Objective : To investigate the relationships of occupational class, educational level and deprivation with mortality in Korea Methods : This study used existing South Korean national data on occupation, educational level, and deprivation and death. Mortality was investigated using registered death data from 1993 to 1997 obtained from the Korean National Statistics Office (NSO) with denominators drawn from the 1995 Census. Statistical analysis consisted of poisson regression modeling and multilevel analysis. Results : The lower occupational class (manual workers) group had a higher mortality rate than the higher occupational class (non-manual workers) group Educational level, and deprivation were both inversely related withand mortality. Occupation was strongly associated with education. Area-based deprivation indicators and individual indices for social class made an independent contribution to the mortality risk. Conclusions : The findings of this study suggests that the relationships of occupational class, educational level and deprivation with mortality appears to be stronger in Korea than in European countries.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.1
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• pp.1-8
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• 2014

This paper proposes an emotion classifier from EEG signals based on Bayes' theorem and a machine learning using a perceptron convergence algorithm. The emotions are represented on the valence and arousal dimensions. The fast Fourier transform spectrum analysis is used to extract features from the EEG signals. To verify the proposed method, we use an open database for emotion analysis using physiological signal (DEAP) and compare it with C-SVC which is one of the support vector machines. An emotion is defined as two-level class and three-level class in both valence and arousal dimensions. For the two-level class case, the accuracy of the valence and arousal estimation is 67% and 66%, respectively. For the three-level class case, the accuracy is 53% and 51%, respectively. Compared with the best case of the C-SVC, the proposed classifier gave 4% and 8% more accurate estimations of valence and arousal for the two-level class. In estimation of three-level class, the proposed method showed a similar performance to the best case of the C-SVC.

• Journal of Power Electronics
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• v.18 no.1
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• pp.277-288
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• 2018

Wireless inductive power transfer (IPT) technology is used in many applications today. A compact and high-frequency primary side inverter is one of the most important parts of a WPT system. In this study, a modified class EF-type voltage-fed multi-resonant inverter has been proposed for WPT application at a frequency range of 85-100 kHz. Instead of an infinite input choke inductor, a resonant inductor is used to reduce loss and power density. The peak voltage stress across the MOSFET has been reduced to almost 60% from a class-E inverter using a passive clamping circuit. A simple yet effective design procedure has been presented to calculate the various component values of the proposed inverter. The overall system is simulated using MATLAB/SimPowerSystem to verify the theoretical concepts. A 500-W prototype was built and tested to validate the simulated results. The inverter exhibited 90% efficiency at nearly perfect alignment condition, and efficiency reduced gradually with the misalignment of WPT coils. The proposed inverter maintains zero-voltage switching (ZVS) during considerable load changes and possesses all the inherent advantages of class E-type inverters.