• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.905_906
• /
• 2009

본 논문은 한전 전력연구원이 주관하고 명지대학교와 (주)효성이 참여하는 연구과제의 결과물로써 다중펄스 컨버터와 PWM 컨버터로 구성된 20MVA급 Back-to-Back STATCOM의 시스템 구성 및 제어 동작특성에 대하여 정리하였다. 한전 전력연구원과 (주)효성이 국책과제를 통해 순수 국내기술로 개발한 10MVA급 다중펄스 STATCOM의 활용방안으로 10MVA급 PWM STATCOM 1기를 추가하여 두 STATCOM 각각의 DC link단을 연계시킨 20MVA급 Back-to-Back STATCOM을 구성하고 제어 알고리즘을 개발하였다. 또한 PSCAD/EMTDC 소프트웨어를 이용하여 개발한 Back-to-Back STATCOM의 제어 및 동작특성을 분석하였다.

• Korean Journal of Child Studies
• /
• v.24 no.2
• /
• pp.15-33
• /
• 2003

The 120 participants of this study were 5- and 9-year-old children and their mothers. Children responded to 24 prosocial moral reasoning dilemmas and 8 prosocial decision-making tasks. Mothers' prosocial moral reasoning was assessed with questionnaires. Level of moral reasoning was higher in distant than in close relationships. 5-year-olds in preoperational stage used the complex situational cues in their reasoning, and prosocial moral reasoning of 9-year-olds was positively related to mothers' prosocial moral reasoning in the situation with conditions of distant relationship, low costs, and internal responsibility. Children made more helping decisions in close than in distant relationship situations, low rather than high cost situations, and external rather than internal responsibility situations. 5-year-olds whose mothers were high in level of prosocial moral reasoning were more helpful.

• Proceedings of the KIEE Conference
• /
• 2000.07b
• /
• pp.1377-1380
• /
• 2000

본 논문은 산업자원부 중기거점기술개발사업의 일환인 '전동차 추진장치 기술 개발 과제'로 개발된 전동차 구동 시스템에 대하여 서술하고 있다. 개발된 전동차 구동 시스템은 4대의 210kW 유도전동기를 병렬로 구동하며 주 전력 소자로 IGBT(Insulated Gate Bipolar Transisotr)를 사용하여 스너버 회로가 없는 간단하고 신뢰성 있는 시스템을 구현하였다. 제어 기법으로는 벡터 제어 기법을 적용하여 저속 기동 및 가속시의 토오크 제어 특성을 향상시켰다. 본 논문에서는 전체시스템의 구성 및 특성을 약술하고, 적용된 벡터제어에 대하여 논하였다. 그리고 본 과제를 위해 새로 제작된 전동차 1편성을 이용하여 한국철도차량주식회사 상주공장의 시험 전차선에서 주행 시험을 실시한 결과 개발된 전동차 구동 시스템의 성능이 목표 사양을 만족함을 확인하였다.

• Nuclear Engineering and Technology
• /
• v.25 no.3
• /
• pp.480-496
• /
• 1993

원자력발전 핵연료주기에서 고려하여야 할 중요한 요소의 하나는 사용후핵연료에서 비롯되는 고준위 방사성핵종이다. 고준위 방사성핵종의 처분 방법으로서 심지층처분방식은 가장 손쉬운 방법이기는 하나 매우 장시간의 감시가 필요하며, 특히 자연환경으로의 누출가능성이 커서 이의 대안으로서 외국 몇 나라에서는 소위 소멸처리(Transmutation)방법에 대한 연구를 활발히 하고 있다. 현시점에서 소멸처리 방법으로 가장 타당성이 있는 것으로 여겨지는 것은 원자로를 이용하는 것과 가속기 구동 미임계 시스템 (Accelerator-Driven Subcritical System)을 이용하는 방법이다. 본 기고문에서는 이들 방법을 중심으로 다양한 소멸처리 방법의 소개와 기술적인 문제점(특히 핵 특성관점에서)에 대한 고찰 그리고 향후 연구과제 등에 대하여 기술하고자 한다. 비록 소멸처리 시스템의 현실화를 위해서는 해결되어야 할 과제가 많이 남아 있지만, 기술적인 가능성과 방사능의 소멸이란 면을 고려할 때 소멸처리시스템은 궁극적인 방사성핵종 처리기술로서 연구·개발할 충분한 가치가 있는 것으로 판단된다.

• Journal of The Korean Association For Science Education
• /
• v.31 no.5
• /
• pp.694-708
• /
• 2011

In this study, we developed tasks including cognitive scaffolding for students to explain scientific phenomena using valid evidences in science classroom and sought to investigate how tasks influence the development of small group scientific argumentation. Heterogeneous small groups in gender and achievement were organized in one classroom and the tasks were applied to the class. Students were asked to write down their own ideas, share individual ideas, and then choose the most plausible opinion in a group. One group was chosen for investigating the effect of tasks on the development of small group argumentation through the analysis of discourse transcripts of the group in 10 lessons, students' semi-structured interview, field note, and students' pre- and post argument tests. The discrepant argument examples were included in the tasks for students to refute an argument presenting evidences. Moreover, comparing opinion within the group and persuading others were included in the tasks to prompt small group argumentation. As a result, students' post-argument test grades were increased than pre-test grades, and they argued involving evidences and reasoning. The high level of arguments has appeared with high ratio of advanced utterances and lengthening of reasoning chain as lessons went on. Students had elaborate claims involving valid evidences and reasoning by reflective and critical thinking while discussing about the tasks. In addition, tasks which could have various warrants based on the data led to students' spontaneous participation. Therefore, this study has significance in understanding the context of developing small group argumentation, providing information about teaching and learning context prompting students to construct arguments in science inquiry lessons in middle school.

• Water for future
• /
• v.51 no.10
• /
• pp.31-37
• /
• 2018

• 전기의세계
• /
• v.46 no.4
• /
• pp.15-21
• /
• 1997

이 논문에서는 기능성유기박막의 박막제조방법과 박막의 특성, 금후의 연구과제 등에 대해 기술하고자 한다.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.19 no.2
• /
• pp.165-171
• /
• 2016

In this study, the characterization of projects and analysis of R&D products and commercialization performances were done to serve some implications on the policy decisions related to the commercialization of R&D in marine and fisheries sector. A total of 212 R&D projects with 144 ones for marine and 68 for fisheries performed for 5 years, from 2010 to 2014, were sorted and analyzed on the respect of government budget, main performing body, and research period. The R&D result and commercialization performance were substituted to quantitative indicators, such as the number of published papers, the number of patents, the amount of the technology royalty, the number of technology transfers, and the improvement of public service, which were subjects to be analysed. Based on the results, this study suggests the policy implications for the success of national R&D program; 1) diversifying the main performing body, 2) operating the system for sharing research infrastructures among researchers, 3) introducing the adaptable R&D program management, 4) expending the portion of grants without detailed requests for proposal, and 5) leaning the investigation of R&D budgets on projects focusing on the practicalization and commercialization.

• Journal of the Korean School Mathematics Society
• /
• v.16 no.1
• /
• pp.241-263
• /
• 2013

The purpose of this paper is to investigate high school students' reasoning characteristics in problem solving. To do this, we selected five high school students as participants and presented them some open problems which allow diverse solving approaches, and recorded their problem solving process. Through analyzing their problem solving process relate to their solution, we found the followings: First, students quickly try to calculate without understanding the given problem. Second, students concern whether their solution is right or not rather than consider mathematical warrants for the results of their strategies. Third, students have difficulties to consider more than two conditions at the same time necessary to solve problem. Forth, students are not familiar to use precedence knowledge relate to given tasks. Fifth, students could have difficulties in problem solving because of easy generalization.

• Journal of Elementary Mathematics Education in Korea
• /
• v.17 no.1
• /
• pp.165-184
• /
• 2013

In order to utilize Sphinx Puzzle in shape education or deductive reasoning, a lesson employing Dienes' six-stage theory of learning mathematics was structured to be applied to students of 6th grade of elementary school. 4 students of 6th grade of elementary school, the researcher's current workplace, were selected as subjects. The academic achievement level of 4 subjects range across top to medium, who are generally enthusiastic and hardworking in learning activities. During the 3 lessons, the researcher played role as the guide and observer, recorded observation, collected activity sheet written by subjects, presentation materials, essays on the experience, interview data, and analyzed them to the detail. A task of finding every possible triangle out of pieces of Sphinx Puzzle was given, and until 6 steps of formalization was set, students' attitude to find a better way of mathematical deduction, especially that of operational thinking and deductive thinking, was carefully observed and analyzed.