• Journal of Power Electronics
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• v.14 no.3
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• pp.421-431
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• 2014

A DSP-based self-adaptive proportional-integral (PI) controller to control a DC-DC converter is proposed in this paper. The full-bridge topology is adopted here to obtain higher power output capability and higher conversion efficiency. The converter adopts the zero-voltage-switching (ZVS) technique to reduce the conduction losses. A parallel secondary active clamp circuit is added to deal with the voltage overshoot and ringing effect on the transformer's secondary side. A self-adaptive PI controller is proposed to replace the traditional PI controller. Moreover, the designed converter adopts the constant-current and constant-voltage (CC-CV) output control strategy. The secondary active clamp mechanism is discussed in detail. The effectiveness of the proposed converter was experimentally verified by an IGBT-based 10kW prototype.

• Journal of The Korean Association For Science Education
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• v.8 no.2
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• pp.1-16
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• 1988

Secondary schools in Korea have been faced with several critical problems in their science education. Among them the most fundamental are the problems which involve the development and operation of science curricula. This study had, therefore, its objective to develop the suggestions for sabstantial science curricula of secondary schools. Actually the objectives are trifold as following specific description. ${\circ}$Analysis of the rationale and theory of science curricula. ${\circ}$Status survey of secondary science curricula and identification of the problems in development and operation of the curriculum in foreign and Korean secondary schools. ${\circ}$Development of suggestions for substantial science curriculam of secondary school. In order to attain these objectives the methods of literauare survey. questionaire and interview were used. Through these methods several problems are found and identified. The major findings and problems identified in this study are: ${\circ}$aims, goals, and objectives of science education are not dfferentiated. ${\circ}$the curricula show discipline-centered seleetion and organization of the content:neglect the relationship of science-technology-society and life-world context. ${\circ}$shortage of weekly instructional hours for science subjects. Other findings and problems are described and the descriptions of the suggestions for substantial curricula are followed at the end of this paper.

• Hwankyungkyoyuk
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• v.14 no.1
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• pp.66-80
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• 2001

In this study, the current status and the desirable ways for improvement of the examination system for the employment of the environmental education teachers in the secondary school were investigated. For the study, first, problems and reasons, and the counterplan of policy on the teacher connected directly with the examination employing secondary school teachers through exploration of the related literatures were analyzed; second, it was identified that the essential quality which environmental education teachers should have ready; third, the curriculum of environmental education teacher training universities and the seventh environmental curriculum were examined to provide a basis of discussion on the principle of setting questions for the employment of environmental education teachers; fourth, the number of recruitment, the number of examinee, the principle of setting questions, the composition of questions, and the distribution of scores of the examination which were carried out in the school year 2000 and 2001 were compared and analyzed; finally, the basis of the above analyses, recommendations to consider the examination system for the employment of environmental education teachers in the secondary school were presented as follows: first, the team managing the examination for the employment should reflect the aims and special contents of environmental education to discuss and decide the principle of setting questions on the environmental course; second, the proportion of subject matter education in the examination for environmental education teachers should be increased; third, the validity of questions for the examination should be clarified and the difficulty level of the questions should be low.

• Journal of The Korean Association For Science Education
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• v.24 no.1
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• pp.48-62
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• 2004

This research aimed to investigate whether Korean education programs for secondary science teachers reflect constructivist perspectives. To identify how to introduce the idea of constructivism and STS into the courses of the current Korean education programs for secondary science teachers, two programs were selected: the Qualifying In-service Program held in Seoul and the pre-service programs established in the four departments of science education of the Korean National University of Education in Chungbuk. The course guidebooks, syllabi, and text materials prepared for implementation of the courses were collected and analyzed. E-mail correspondence with the program instructors who had conveyed both ideas to the trainees provided us more precise information about the characteristics of the classes, such as the total time provided the ideas and the teaching strategies used to implement the classes. The results indicated that the pre-service programs included the ideas of constructivism and STS more than did the Qualifying In-service Program. It is necessary that the courses included in the Korean in-service program, in particular the Qualifying In-service Program for secondary science teachers, have to be more focused on the constructivist perspectives.

• Journal of The Korean Association For Science Education
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• v.25 no.7
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• pp.794-800
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• 2005

The purpose of this study was to examine the state of management and science teachers perception of science classes and clubs in secondary schools. There ware 125 participants (75 middle school teachers and 50 high school teachers) from eight metropolitan cities and local areas, and more than 80% of the participants had managed science classes or clubs. Results found that a significant number of science teachers felt it necessary to manage science classes and/or clubs in secondary schools. They believed the classes and/or clubs to be beneficial in the activation of students' interest in science, even though they might not be effective ways of improving scientific achievement. In addition, it was found that secondary science teachers desire financial support, in-service programs, and efficacious programs supporting science class and club management.

• Journal of the Semiconductor & Display Technology
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• v.6 no.1 s.18
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• pp.53-57
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• 2007

In this paper, the intelligent estimation algorithm is developed for residual quantity estimate of lithium secondary cell and we suggest the control algorithm to get battery SOC through thermal modeling of electric cell. Lithium secondary cell gives cycle life, charge characteristic, discharge characteristic, temperature characteristic, self-discharge characteristic and the capacity recovery rate etc. Therefore, we make an accurate estimate of the capacity of battery according to thermal modeling to know the capacity of electric cell that is decreased by various special quality of lithium secondary cell. And we show effectiveness through comparison of value as result that use simulation and fuzzy logic.

• Journal of Digital Convergence
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• v.19 no.7
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• pp.227-236
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• 2021

This study aims to develop an AI education program for secondary school students to help understand AI and to provide an experience of solving real-life problems by using AI, and to analyze the effectiveness of education. The education program based on the AI education system for K-12 developed in the previous study was composed of a total of 12 lessons by selecting the self-driving cars, which is emerging as a recent issue among real life problems, as the main topic. Classes were conducted for secondary school students who had experience in software education, and the effectiveness of education and class satisfaction were analyzed. As a result of the analysis, it was confirmed that the understanding of AI and the sense of AI efficacy were improved, and the class satisfaction was high in all items such as educational content, fun in class, difficulty of class, and interest in AI. Based on these results, implications for AI education for secondary students were proposed.

• 한국과학교육학회:학술대회논문집
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• 2008.08a
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• pp.47-56
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• 2008

This article presents how in China mainland a school and a school district find their science teachers. Based on studying relevant materials and years of intensive involvement in teacher education and recruitment practices the authors draw three features of the current secondary science teachers' employment system in China mainland: certification control conducted very loosely selection criteria and process vary with schools and school districts due to the remarkable difference existed among them the normal universities/colleges established originally only for secondary science teacher education still play a vital role in shaping effecting quality of teacher candidates although no one of them for a long time have focused on only doing what they were supposed to do. For further development, changes and essential reform are expected duo to the increasing promotion toward the internal quality of education and therefore high quality of teachers and teacher candidates.

• Research in Mathematical Education
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• v.7 no.2
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• pp.91-99
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• 2003

Isik & K$_1$l$_1$c (1998: Mathematics Education and its Appraising in the Primary School Teacher Certificate) found that many prospective mathematics teachers for primary schools who attended at newly established certificate programs made significant misconception on mathematics education because they were not graduates of education faculties. The levels of conceptual knowledge and procedural knowledge of students from a secondary school in Erzurum, Turkey were investigated in order to reveal how serious misconception the teachers have been made so far. The conceptual knowledge is very important to students, however in this research, it was found that procedural knowledge was much more important than conceptual knowledge.

• East Asian mathematical journal
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• v.29 no.2
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• pp.169-187
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• 2013

The purpose of this study is to analyze whether mathematics education course can improve secondary pre-service math teacher' belief and correlation on pre-service math teacher' belief and mathematics education achievement. In order to achieve this purpose, the test was conducted to the subject of 34 pre-service secondary math teachers of the grade 2 and grade 4 who were chosen from H university in D city and we analyzed the results. Findings on this study are as follows. First, there was meaningful difference in the pre-service math teacher' belief with significant level of 0.05. This proved that mathematics education course was effective on improving pre-service math teacher' belief. Second, there was not meaningful correlation in the pre-service math teacher' belief and mathematics education achievement.