• Journal of Korean Society of Industrial and Systems Engineering
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• 제37권1호
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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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• 제18권1호
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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.

• Human Ecology Research
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• 제61권2호
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• pp.195-218
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• 2023

The purpose of this study was to present a class case that verified the validity, reliability, and usefulness of a portfolio assessment in a cohousing class in the housing area of home economics. To achieve this objective, 241 male and female students in eight classes of the third grade of a junior high school in Gyeonggi-do, Korea, were enrolled in a project class on establishing a cohousing village in which the portfolio assessment method was applied for a total of 10 sessions for approximately four weeks from May 24 to June 16, 2021. To ensure the validity of the portfolio assessment, we designed the lesson after presenting the curriculum goals in detail using the backward design model and developed a specific rubric and conducted all evaluations and feedback based on the rubric to ensure objectivity and reliability. The online tool Padlet was used as a portfolio, which allowed students to easily upload their work, receive feedback from the teacher, and interact with their peers. After the class, the students reflected on the rubric and were generally satisfied with the class using portfolio assessment. This study is expected to facilitate the use of the portfolio assessment method in the classroom, while also supporting student growth and development.

• Journal for History of Mathematics
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• 제15권2호
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• pp.113-124
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• 2002

The main purpose of this study is to classify types of class using computer in the school mathematics classroom. For this purpose, we will first survey the Tyle's theory relate to the curriculum model and its details. Then we will investigate the crucial points using computer in the school mathematics classroom in the viewpoint of Glaser's teaching model. From this, we will device several types of mathematics class using computer.

• Proceedings of the KIEE Conference
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1466-1467
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• 2007

A new parameter W/R for the class I test have been introduced in the IEC 61643-1 published in 2005. One of the possible test impulses which meets the parameters for class I test is the 10/350 [${\mu}s$] waveshape proposed in IEC61312-1. 10/350 [${\mu}s$] waveshape meets parameters for class I test in the IEC 61643-1. The impulse generator for making the 10/350 [${\mu}s$] waveshape is consist of IVG, ICG, crowbar coil and crowbar switch. The electric change Q and the specific energy W/R were measured and calculated using the exclusive use measuring software according to the formula of IEC 611643-1. We verified the correspondence between measured results using impulse generator and recommended parameters by IEC 61643-1.

• The korean journal of orthodontics
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• 제42권4호
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• pp.182-189
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• 2012

Objective: The aims of this study were to use a 3-dimensional (3D) system to compare molar relationship assessments performed from the buccal and lingual aspects, and to measure differences in occlusal contact areas between Class II and Class I molar relationships. Methods: Study casts (232 pairs from 232 subjects, yielding a total of 380 sides) were evaluated from both the buccal and lingual aspects, so that molar relationships could be classified according to the scheme devised by Liu and Melsen. Occlusal contact areas were quantified using 3D digital models, which were generated through surface scanning of the study casts. Results: A cusp-to-central fossa relationship was observed from the lingual aspect in the majority of cases classified from the buccal aspect as Class I (89.6%) or mild Class II (86.7%). However, severe Class II cases had lingual cusp-to-mesial triangular fossa or marginal ridge relationships. Mean occlusal contact areas were similar in the Class I and mild Class II groups, while the severe Class II group had significantly lower values than either of the other 2 groups (p < 0.05). Conclusions: Buccal and lingual assessments of molar relationships were not always consistent. Occlusal contact areas were lowest for the Class II-severe group, which seems to have the worst molar relationships - especially as seen from the lingual aspect.

• Journal of the Institute of Electronics Engineers of Korea TC
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• 제45권1호
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• pp.110-114
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• 2008

In this paper, high efficient class F power amplifier with dual band has been realized. Dual band power amplifier have used modify stub matching for single FET, center frequency 2.14GHz and 5.2GHz respectively. Dual band amplifier is 32.65dBm output power, gain 11dB and PAE 36% at the 2.14GHz, 7dB gain at the 5.2GHz. Design of a dual band class F power amplifier using harmonic control circuit. The measured are 9.9dB gain, 30dBm output power and PAE 55% at the 2.14GHz, 11.7dB gain at the 5.2GHz. This paper is being used the load-pull method and it maximizes output power and it is using the only one transistor in the paper. As a result, this research will obtain a dual band high PAE power amplifier.

• Journal of Korean Elementary Science Education
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• 제33권1호
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• pp.69-81
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• 2014

This study was to find out the effects of out-of-class environmental experience learning on elementary students' environmental literacy. For this study, we developed and applied environmental education program utilizing out-of-class facilities and ecological park for the 5th-grade students. The subjects of this study were the 5th grade students of an elementary school located in Si-hung city. The study was carried out for two groups, an experiment group of 29 students and control group of 29 students. The education program using out-of-class environmental experience learning was provided to the experiment group while lecture-oriented education program was provided to the control group. The questionnaire used in this study to assess the environmental literacy of the study objects consists of 41 questions under 4 domains (knowledge, emotion, skill, behavior). After observing and analyzing the effects of out-of-class environmental experience learning on students' environmental literacy, we found that the program using the out-of-class environmental experience learning posed greater impacts than lecture-oriented program. By domains, environmental literacy in 3 domains illustrated positive improvement. In particular, skill domain illustrated much more improvement in environmental literacy. But, domain of behavior didn't illustrated improvement in environmental literacy. The result of this study signified that the out-of-class environmental experience learning has positive and effective impact on the environmental literacy. And out-of-class environmental experience learning is more suitable to improve the skill domain of the environmental literacy than lecture-oriented learning. But, it is couldn't improve the domain of behavior. Therefore, in order to improve behavior domain, the program must apply with effective evaluation and home training.

• Asian Pacific Journal of Cancer Prevention
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• 제13권4호
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• pp.1371-1376
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• 2012

Background: Economic status is known to be directly or indirectly related to cancer incidence since it affects accessibility to health-related social resources, preventive medical checkups, and lifestyle. This study investigates the relationship between cancer incidence and family income in Korea. Methods:Using the Korean National Health Insurance cancer registration data in 2009, the relationship between their family income class and cancer risk was analyzed. The age-standardized incidence rates of the major cancers were calculated for men and women separately. After adjusting for age, residential area, and number of family members, cancer risks for major cancers according to family income class were estimated using a logistic regression model. Results: In men, the risk of stomach cancer for Income Class 5 (lowest) was 1.12 times (95% CI 1.02-1.23) higher than that of Income Class 1 (highest), for lung cancer 1.61 times (95% CI 1.43-1.81) higher, for liver cancer 1.22 times (95% CI 1.08-1.37) higher, and for rectal cancer 1.37 times higher (95% CI 1.18-1.59). In women, the risk of stomach cancer for Income Class 5 was 1.22 times higher (95% CI 1.08-1.37) than that for Income Class 1, while for cervical cancer it was 2.47 times higher (95% CI 2.08-2.94). In contrast, in men, Income Class 1 showed a higher risk of thyroid cancer and prostate cancer than that of Income Class 5, while, in women the same was the case for thyroid cancer. Conclusions: The results show the relationship between family income and cancer risk differs according to type of cancer.

• 한국데이터정보과학회:학술대회논문집
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• 한국데이터정보과학회 2003년도 추계학술대회
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• pp.123-123
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• 2003

More elaborated methods allowing the usage of binary classifiers for the resolution of multi-class classification problems are briefly presented. This way of using FSVC to learn a K-class classification problem consists in choosing the maximum applied to the outputs of K FSVC solving a one-per-class decomposition of the general problem.