• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.174-176
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• 2008

HYOSUNG manufactured and tested 1kw class PEFC systems to generate electrical and thermal energy for each residential usage. In particular, HYOSUNG developed Power conditioning system that performs about 91% electrical conversion ratio specified in 1kW class PEFC systems. Prior to system integration, we tested each performances of components to derive control issues from it. In addition, we have been developing the adequate simulator to describe and predict system performance. In this paper, we verified HYOSUNG's 1kW class PEFC systems are valid for residential energy sureces by testing the characteristics of systems and performances of main component.

• 대한전기학회논문지
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• 제41권4호
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• pp.331-338
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• 1992

The application of Connectionist expert system using neural network to fault diagnosis of power system is presented and compared with rule-based expert system. Also, the merits of Connectionist model using neural network is presented. In this paper, the neural network for fault diagnosis is hierarchically composed by 3 neural network classes. The whole power system is divided into subsystems, the neural networks (Class II) which take charge of each subsystem and the neural network (Class III) which connects subsystems are composed. Every section of power system is classified into one of the typical sections which can be applied with same diagnosis rules, as line-section, bus-section, transformer-section. For each typical section, only one neural network (Class I) is composed. As the proposed model has hierarchical structure, the great reduction of learning structure is achieved. With parallel distributed processing, we show the possibility of on-line fault diagnosis.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.57-60
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• 2008

KEPRI has studied planar type SOFC stacks using anode-supported single cells and kW class co-generation systems for residential power generation. A 1kW class SOFC system consisted of a hot box part, a cold BOP part and a water reservoir. A hot box part contains a SOFC stack made up of 48 single cells and ferritic stainless steel interconnectors, a fuel reformer, a catalytic combustor and heat exchangers. Thermal management and insulation system were especially designed for self-sustainable operation. A cold BOP part was composed of blowers, pumps, a water trap and system control units. When a 1kW class SOFC system was operated at $750^{\circ}C$ with hydrogen after pre-treatment process, the stack power was 1.2kW at 30 A and 1.6kW at 50A. Turning off an electric furnace, the SOFC system was operated using hydrogen and city gas without any external heat source. Under self-sustainable operation conditions, the stack power was about 1.3kW with hydrogen and 1.2kW with city gas respectively. The system also recuperated heat of about 1.1kW by making hot water.

• 정보교육학회논문지
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• 제12권2호
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• pp.131-139
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• 2008

본 연구는 협력적 지식구축을 목적으로 하는 CSCL (Computer-Supported Collaborative Learning) 환경을 이용하여 교육주체간의 협동적 상호작용이 원활히 이루어질 수 있도록 하는 모바일 학급경영지원시스템을 구현하는데 목적이 있다. 이러한 목적을 위해 학급경영과 CSCL, 무선인터넷을 이론적으로 탐색하고 학급경영과 무선인터넷의 관계를 파악하여 학급경영을 지원하는 모바일 학급경영지원 시스템의 설계요소 및 전략을 수립하였다. 이를 기반으로 모바일 학급경영지원시스템을 설계하고 개발하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.1167-1168
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• 2006

Recently, the concern for environmental issue has been rising in the world such as global warming and breaking of ozone barrier by exhausting carbon dioxide(CO2) and Freon. In this situation, Photovoltaic(PV) and hydrogen energy system for utilizing clean and renewable energy was highlighted to contribute very much against the global warming prevention. Until now, authors have studied EMTDC model Development of Solar-powered Hydrogen production system and manufactured the 600W class actual PV-SPE system. Which was established in 2004 to produce highly pure hydrogen energized by PV power generation system. Sooner, authors will establish 100kW class PV-SPE system. Economically, this system produce large amount of hydrogen. In this paper, all data of 100kW class PV-SPE system will be simulated by using PSCAD/EMTDC.

• 수산해양교육연구
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• 제25권4호
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• pp.781-800
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• 2013

The purpose of this study was to investigate perception of primary school teachers about operation of after-school computer class. Research questions were set up as follows: First, what type is preferred on the operation type for after-school computer class? Second, what is the perception about the adequacy of contents for after-school computer class? Third, what is the perception about instructors' expertise? Fourth, what is the perception about the effects of after-school computer class? Finally, what is the perception about facilities/ equipment and evaluation system of after-school computer class? To figure out these questions, this study conducted literature review and questionnaire survey. The results of this study are as follows: First, approximately 82% of respondents preferred to have after-school computer class operated by outsourced agency. Second, overall, the perceptions about the operation of after-school computer class were positive: The adequacy of contents, instructors' expertise, the effects, facilities/ equipment and evaluation system are seen as mostly positive. Third, its differences between school self-operated computer class and private sector computer class were insignificant. Fourth, its differences among various sizes of the school were significant. The implementaion of after-school computer class was considered as more positive in small schools. Finally, researchers suggested that it was necessary to develop an plan considering school sizes for more efficient implementation of after-school computer class.

• 대한수학회지
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• 제56권4호
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• pp.869-915
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• 2019

Let H be a Krull monoid with class group G such that every class contains a prime divisor. Then every nonunit $a{\in}H$ can be written as a finite product of irreducible elements. If $a=u_1{\cdot}\;{\ldots}\;{\cdot}u_k$ with irreducibles $u_1,{\ldots},u_k{\in}H$, then k is called the length of the factorization and the set L(a) of all possible k is the set of lengths of a. It is well-known that the system ${\mathcal{L}}(H)=\{{\mathcal{L}}(a){\mid}a{\in}H\}$ depends only on the class group G. We study the inverse question asking whether the system ${\mathcal{L}}(H)$ is characteristic for the class group. Let H' be a further Krull monoid with class group G' such that every class contains a prime divisor and suppose that ${\mathcal{L}}(H)={\mathcal{L}}(H^{\prime})$. We show that, if one of the groups G and G' is finite and has rank at most two, then G and G' are isomorphic (apart from two well-known exceptions).

• 비교교육연구
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• 제28권2호
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• pp.77-95
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• 2018

본 연구는 수업관찰을 위한 양적 측정도구로서 CLASS (Classroom Assessment Scoring System)를 소개하고 그 특성을 이해하는데 목적이 있다. CLASS는 수업의 질을 평가하기 위해 개발되었고 미국 전역에서 활용되고 있다. CLASS는 수업에서 교사와 학생의 상호 작용을 측정하고 주제 영역 및 학생연령 별로 상호 작용을 확인하는 도구로서 세 가지 질적 영역, 즉, 정서적 지원, 학급 조직, 교육지원 등으로 구성된다. CLASS는 학생들의 학습을 위한 핵심으로 교사와 학생들 간의 상호 작용 패턴에 중점을 둔다. 관찰자가 교사와 학생을 10분~15분 동안 3~4번 관찰하며, 관찰은 행동과 반응의 유형에 따라 1에서 7사이의 연속된 등급척도로 평가된다. CLASS의 활용 가능성을 확인하기 위해, 경력이 많은 전문가 교사의 학급과 초임교사의 학급에 적용하여 분석해 보았다. 전문가 교사는 학생들이 주도적으로 수업을 이끌어가는 데 집중을 하였고, 초임 교사는 교과의 내용을 다루는 데 집중을 하였다. 초임교사는 학급 분위기를 긍정적으로 만들고, 학생들에게 피드백 해주는 데 비교적 많은 노력을 기울였다. 전문가 교사는 학생의 의견, 질문, 미세한 감정 등을 파악하고 드러내는 데 보다 많은 노력을 기울였다. CLASS는 교실에서 어떤 유형의 행동과 상호 작용이 발생하는지를 기록하고 이를 분석하는 관찰도구로서 활용이 가능할 것이다.

• 한국도서관정보학회지
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• 제32권2호
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• pp.323-347
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• 2001

이 연구는 군사학 분야의 인터넷 학술정보자원을 효율적으로 조직, 활용하기 위한 청문서 분류체계의 모형을 제시하기 위해 시도된 것이다. 이를 위해, 우선 일반문헌분류표 가운데 군사정보에 관한 항목을 상세하게 전개하고 있는 LCC의 Class U(Military Science)와 Class V(Naval Class)를 상세히 분석하고, 웹 문서 분류체계 중 체계적 분류방식을 도입하고 있는 Yahoo!의 분류항목(처음/정부/군사)을 비교 분석하였다. 아울러 웹 문서 분류체계의 새로운 설계를 위해 기존의 Yahoo! Korea와 심마니, Yahoo! US를 종합적으로 비교 분석하였다. 이와 같은 비교 분석의 결과를 바탕으로, 실제적인 분류체계의 모형을 제시하였다.

• 교육녹색환경연구
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• 제9권3호
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• pp.20-33
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• 2010

The purpose of this research is to investigate and analyze the recognition of students and teachers towards an influence of a subject classroom system to teacher's learning activities and student's learning attitude. The study was subjected to students and teachers at a school that has innovatively operated subject classroom system from before 2009. The results of the research are as follows. First, the result of investigation shows that the quality of class has been improved. The formats of managing class and class materials have become various. Second, there is an affirmative exchange in student's learning attitude, such as student's active participation, concentration, preparation and interest toward a class. Third, the fifty percent of teachers answered it that a block time system and intensive study system is required to manage an efficient subject classroom system. Lastly, the investigation shows that teachers and students are generally satisfied with running the subject classroom system. However, the satisfaction ratio of students is lower than the one of teachers.