국제 학술지 분석을 통한 시각장애학생의 학습 관련 보조공학 도구 연구 동향 조사

류현,이해균 한국특수교육학회 2014 한국특수교육학회 학술대회 Vol.2014 No.-

마음의 돌

류현 중앙대학교 예술대학 문예창작학과 1991 창작문화 Vol.8 No.-

자기구동 동기 정류의 공진 토플로지 응용에 대한 연구

柳鉉,朴鍾伯 조선대학교 생산기술연구소 1996 生産技術硏究 Vol.18 No.2

The MOSFET devices are driver in a resonant fashion by the power circuit, resulting in partial recovery of the energy stored in the parasitic capacitances. The necessity of developing high efficiency-low output voltage converters with very high efficiency for distributed power supply systems, leads to the substitution of the recifier diodes of the output stage by synchronous rectifiers. Resonanl synchronous rectification is, when feasible, the best synchronous rectification technique in high switching frequency resonant topologies. The main feature of this circuit is the addition of a capacitor in parallel with the drain-source of the MOSFET used as a rectifying device. A selection of the resonant topologies where it can be implemented and considerations about the resonant synchronous rectifier are presented in this paper. To verify the utility of these techniques. a 100W(SV,20A)Forward ZVS-MRC has been built and tested, obtaining efficiency over 87%. This converter has also been tested at 3.3V, obtaining efficiency of 84%.

당선소감

류현 천년의시작 2018 (계간)시작 Vol.17 No.1

[당선작] 교양 외 4편

류현 천년의시작 2018 (계간)시작 Vol.17 No.1

순 방향 DC-DC 변환기의 간단하고 효과적인 동기 정류기에 대한 연구

柳鉉,朴鍾伯 조선대학교 생산기술연구소 1997 生産技術硏究 Vol.19 No.1

A simple and efficient MOSFET synchronous rectiflcation circuit suitable for forward DC-DC converters is proposed. The main feature of this circuit is the addition of a capacitor in parallel with the drain-source of the MOSFET used as a rectifying device. This capacitor extends the conduction period of the MOSFET used as a freewheeling device. As a result, a 92% efficiency at 5V for 10A output is achieved.

유기농 아이 외 1편

류현 천년의시작 2018 (계간)시작 Vol.17 No.3

시각장애학교 중등학생의 수학적 성향 분석

류현,이해균 한국시각장애교육&재활학회 2013 시각장애연구 Vol.29 No.2

The Purpose of this study is to analyze mathematical disposition of secondary course students in schools for the blind. It offers basic materials to develope methods and strategies that can enhance their interest and motivation in learning mathematics. To carry out the purpose, secondary course students attending 12 schools for the blind throughout the nation were categorized as gender, course, time at onset of the visual impairment, primary literacy medium for learning, and experience of general education. Questionnaire was distributed and analyzed on behalf of their mathematical disposition. Confidence, adaptability, continuity, interest, self-monitoring and awareness of mathematical applicability were contained in mathematical disposition. The results on mathematical disposition and its components from this investigation were as follows. The mathematical disposition level of secondary course students attending schools for the blind is revealed average. Awareness of mathematical applicability indicates highest level in the mathematical disposition components. Male students indicate higher level than female students do in the mathematical disposition of secondary course students attending schools for the blind. Male students indicate higher level than female students do in their adaptability, continuity, interest of mathematics and awareness of mathematical applicability. Middle school course students indicate higher level than high school course students do in their continuity of mathematics. Braille users indicate higher level than regular print (including regular-sized, large-sized, and enlarged materials) users do in their mathematical adaptability. Students who had taken general education indicate higher level than those who had not taken general education in their mathematical confidence. 본 연구는 시각장애학교 중등학생의 수학 교과 관련 학습 특성을 파악하기 위하여 전국 12개 시각장애학교 중등학생 319명을 대상으로 수학적 성향에 관하여 분석하였다. 이를 수행하기 위해 수학적 성향의 하위 6개요인 24문항의 설문지를 구성하여 도출한 연구 결과를 요약하면 다음과 같다. 첫째, 시각장애학교 중등학생의 수학적 성향은 보통 수준이었고, 하위 요인 중 수학의 가치 인식이 가장 높았다. 둘째, 시각장애학교 중등학생 중 남학생이 여학생보다 수학적 성향이 더 높았으며, 사고 과정의 융통성, 문제 해결에 대한 의지, 수학적 호기심, 수학의 가치 인식도 더 높았다. 중학생이 고등학생보다 문제 해결에 대한 의지가 더 높았고, 사용하는 문자매체가 점자인 학생이 묵자인 학생보다 사고 과정의 융통성이 더 높았다. 일반학교 재학 경험이 있는 학생이 없는 학생보다 수학에 대한 자신감이 더 높았다. 이러한 연구결로 시각장애학교 중등학생의 수학적 성향은 보통의 수준이며, 성별ㆍ과정별 차이는 정안학생과 유사함을 할 수 있다. 이를 중심으로 후속 연구에 필요한 제언을 하였다.

특수교육지원센터 웹 사이트 접근성 및 준수율 분석

류현,강종구 한국지적장애교육학회 2019 지적장애연구 Vol.21 No.1

The purpose of this study was to investigate how special education support center websites guarantee the web accessibility and compliance rate per items for students with disabilities. For the purpose of this study, we investigated the level of accessibility per inspection items of 34 special education support center websites and the compliance rate of investigation items through 24 inspection items of Korean web content accessibility guidelines 2.1. The results of this study were as follows: First, the level of accessibility of special education support center websites was shown less than web accessibility quality certification criteria(95%) for quality certification for web accessibility. Second, the exploration on the compliance rate per investigation items of special education support center websites showed all the four areas(ease of perception, ease of operation, ease of understanding, and robustness) were lower than certification criteria of quality. This study shows that students with disabilities can experience difficulties in the use of web because the accessibility of special education support center websites was not guaranteed. Therefore, web accessibility needs to be urgently improved. In addition, this study shows the necessity of various improvements related to specail education support center website such as the improvement of awareness on website development and operating personnels, the acquisition of techniques related to web accessibility, and the improvement of laws or systems related to web accessibility. 본 연구는 특수교육지원센터의 웹 사이트들이 장애학생들에 대한 웹 사이트의 접근성 및 항목별 준수율이 어느 정도 지키고 있는지를 알아보기 위한 연구이다. 이를 위해 한국형 웹 콘텐츠 접근성 지침 2.1의 24개 검사 항목을 통해 34개 특수교육지원센터의 웹 사이트 접근성 수준과 검사 항목별 준수율을 알아보았다. 본 연구의 결과는 다음과 같다. 첫째, 특수교육지원센터 웹 사이트의 접근성 수준은 웹 접근성을 위한 품질인증 심사 기준(95%)보다 낮게 나타났다. 둘째, 특수교육지원센터 웹 사이트의 검사 항목별 준수율은 4개 영역(인식의 용이성, 운용의 용이성, 이해의 용이성, 견고성) 모두에서 품질인증 심사 기준보다 낮게 나타났다. 본 연구는 특수교육지원센터 웹 사이트의 접근성이 보장되지 않아 웹 사이트에 있는 정보를 장애학생이 웹을 활용하는 데 어려움을 경험할 수 있음을 보여주고 있다. 따라서 웹 접근성은 시급히 개선될 필요가 있다. 이와 함께 본 연구는 특수교육지원센터 웹 사이트와 관련하여 웹 사이트 개발 및 운영 인력의 인식 개선, 웹 접근성 관련 기술 습득, 웹 접근성 관련 법령이나 제도의 개선 등이 필요함을 보여주고 있다.

Effects of Tooth Whitening and Topical Fluoride Application on Shade and Translucency Changes in Tooth with Early Caries Lesion

류현,김정숙,이명구,김용성 대한예방치과학회 2010 International Journal of Clinical Preventive Denti Vol.6 No.1

Objective: The purpose of this study was to evaluate shade and translucency change by means of various topical fluoride application after tooth whitening on teeth with artificial caries lesions. Materials and method: 84 extracted anterior teeth were selected and induced to artificial caries by 0.1 M lactic acid-sodium hydroxide buffer solution, then tooth whitening treatment were performed for 2 weeks. Topical fluoride application was sequentially applied for 4 times. Improvement of shade and translucency were checked by Shadescan and evaluated according to types of whitening agents, topical fluoride agents and application methods. Results: By application of tooth whitening agent, translucency seemed to be increased in all groups (p<0.05), but after 2 weeks, there was no significant difference within group and also between group comparisons (p>0.05). Except of 22% carbamide peroxide gel application group, value difference ratio was decreased significantly and value difference between the lesion and normal tooth area seemed to be increased (p<0.05). At the beginning of fluoride application, translucency was improved significantly in 0.1% sodium fluoride strip group and fluoride varnish application groups (p<0.05) ; at 4 weeks, all groups showed the significantly increased translucency (p<0.05). There was no significant difference between groups comparisons (p>0.05). Control group and 2% sodium fluoride strip application group showed constant increasing of value difference ratio between the lesion and normal tooth area (p<0.05) ; 0.1% sodium fluoride strip group seemed to be steady state ; fluoride varnish group showed continuous recovery of value difference ratio (p<0.05). Conclusion: It seemed that demineralized area of tooth with early caries was remineralized without any treatment, in addtion fluoride application could make it possible to accelerate recovery of tooth shade and translucency. Clinically in case of patient showed incipient caries in their anterior teeth, just applying whitening agent had any alternative plan could make additional inconsistency and demineralization. It was suggested that fluoride application after whitening to such patients could make more desirable improvement of shade and advanced remineralization.