Microstructured Air Cavities as High-Index Contrast Substrates with Strong Diffraction for Light-Emitting Diodes

Moon, Yoon-Jong,Moon, Daeyoung,Jang, Jeonghwan,Na, Jin-Young,Song, Jung-Hwan,Seo, Min-Kyo,Kim, Sunghee,Bae, Dukkyu,Park, Eun Hyun,Park, Yongjo,Kim, Sun-Kyung,Yoon, Euijoon American Chemical Society 2016 Nano letters Vol.16 No.5

<P>Two-dimensional high-index-contrast dielectric gratings exhibit unconventional transmission and reflection due to their morphologies. For light-emitting devices, these characteristics help guided modes defeat total internal reflections, thereby enhancing the outcoupling efficiency into an ambient medium. However, the outcoupling ability is typically impeded by the limited index contrast given by pattern media. Here, we report strong-diffraction, high-index contrast cavity engineered substrates (CESs) in which hexagonally arranged hemispherical air cavities are covered with a 80 nm thick crystallized alumina shell. Wavelength-resolved diffraction measurements and Fourier analysis on GaN-grown CESs reveal that the high-index-contrast air/alumina core/shell patterns lead to dramatic excitation of the low-order diffraction modes. Large-area (1075 x 750 mu m(2)) blue-emitting InGaN/GaN light-emitting diodes (LEDs) fabricated on a 3 mu m pitch CES exhibit similar to 39% enhancement in the optical power compared to state-of-the-art, patterned-sapphire-substrate LEDs, while preserving all of the electrical metrics that are relevant to LED devices. Full-vectorial simulations quantitatively demonstrate the enhanced optical power of CES LEDs and show a progressive increase in the extraction efficiency as the air cavity volume is expanded. This trend in light extraction is observed for both lateral- and flip-chip-geometry LEDs. Measurements of far-field profiles indicate a substantial beaming effect for CES LEDs, despite their few-micron-pitch pattern. Near-to-far-field transformation simulations and polarization analysis demonstrate that the improved extraction efficiency of CES LEDs is ascribed to the increase in emissions via the top escape route and to the extraction of transverse-magnetic polarized light.</P>

초등 메이커 교육에서 팅커링(tinkering)의 의미와 유형 탐색

문대영(Daeyoung Moon) 한국실과교육학회 2023 한국실과교육학회지 Vol.36 No.1

이 연구는 초등 메이커 교육의 맥락에서 팅커링의 의미를 탐색하고, 초등 메이커 교육에 적용 가능한 팅커링 유형을 확인하기 위해 수행되었다. 연구의 목적을 달성하기 위해서 팅커링 관련 문헌 고찰을 통해 팅커링의 의미를 탐색하고 팅커링의 유형을 분류하여 도출하였다. 또한, 초등 메이커 교육에 적용 가능한 팅커링 유형에 대한 타당도를 검증하였다. 이 연구의 주요 결과는 다음과 같다. 첫째, 초등 메이커 교육에서 팅커링의 의미를 1) 브리콜뢰르로서의 팅커링, 2) 메이커 활동의 한 분야로서 팅커링, 3) 문제 해결과 놀이로서의 팅커링, 4) 학습 과정으로서의 팅커링 등과 같은 네 가지 관점에서 탐색하였다. 둘째, 초등 메이커 교육에 적용할 수 있는 팅커링 유형을 1) 문제 해결하기, 2) 조작·표현하기, 3) 관찰·탐색하기, 4) 분해·조립하기 등의 네 가지 유형으로 구분하여 제시하였다. 또한, 각 유형의 팅커링에는 1) 손으로(with hands), 2) 놀이하듯(like playing), 3) 스스로 결정하며 (self-determined), 4) 계속 시도하는(try over and over), 5) 학습 과정 (learning process) 등과 같은 공통 요소가 전제 조건으로서 반영되어야 할 것을 제안하였다. This study was conducted to explore the meaning of tinkering in the context of elementary maker education and to identify the types of tinkering applicable to elementary maker education. To achieve this purpose, the meanings of tinkering were elucidated from a review of related literature and the types of tinkering were classified and derived. In addition, the validity of tinkering types applicable to elementary maker education was verified. The main findings of this study were as follows: First, the meaning of tinkering in elementary maker education was interpreted from the following four perspectives: 1) tinkering as bricoleur, 2) tinkering as a discipline of maker activity, 3) tinkering as problem-solving and play, and 4) tinkering as a learning process. Second, the types of tinkering that could be applied in elementary maker education were presented as the following four types: 1) problem-solving, 2) manipulation/expression, 3) observation/exploration, and 4) disassembly/assembly. In addition, the results suggested that the following common elements should be reflected as prerequisites for each type of tinkering: 1) with hands, 2) similar to playing, 3) self-determined, 4) try again, and 5) learning process.

자율주행 자동차의 안전한 평가를 위한 디지털 트윈 및 가상 환경 기반 Vehicle-In-the-Loop Simulation(VILS) 시스템 아키텍처

문대영(Daeyoung Moon),김정현(Junghyun Kim),이민기(Minki Lee),홍준(Jun Hong),이기범(Kibeom Lee) 한국자동차공학회 2022 한국자동차공학회 학술대회 및 전시회 Vol.2022 No.11

초·중등 발명교육 정책 변천에 관한 연구

문대영(Daeyoung Moon) 한국기술교육학회 2022 한국기술교육학회지 Vol.22 No.1

이 연구는 발명교사의 인식을 바탕으로 우리나라 초·중등 발명교육 정책의 변천을 탐색하기 위해 수행되었다. 연구의 목적을 달성하기 위해서 우리나라 초·중등 발명교육의 주요 정책 40개를 도출하여 질문지를 구성하고, 발명교육 경력 10년 이상인 발명교사를 대상으로 조사를 실시하였다. 연구의 주요 결과는 다음과 같다. 첫째, 발명교사가 인식하는 우리나라 초·중등 발명교육 정책의 변곡점은 1) 1995년 교육부 및 시·도교육청과 연계한 발명공작교실(現발명교육센터) 설치, 2) 2007년 학교 정규 교육과정에 발명교육 반영, 3) 2017년 발명교육법(발명교육의 활성화 및 지원에 관한 법률) 공포 등의 3개 정책이다. 둘째, 위의 3개 정책을 변곡점으로 하여 우리나라 초·중등 발명교육 정책은 1) 도입기(1973∼1994), 2) 성장기(1995∼2006), 3) 확산기(2007∼2016), 4) 성숙기(2017∼) 등으로 시기 구분할 수 있다. This study was conducted to explore the changes of primary and secondary invention education policy in Korea based on the recognition of the invention teachers. To achieve the purpose of this study, 40 major policies of elementary and secondary invention education in Korea were derived and questionnaires were constructed. Invention teachers with more than 10 years of invention education experience were surveyed. The main results of this study are as follows:First, the inflection point of the Korean elementary and secondary invention education policy recognized by the invention teachers is three policies: 1) the establishment of the invention work classroom (invention education center) in 1995, 2) the reflection of invention education in the regular school curriculum in 2007, and 3) the invention education law (the Act on the Activation and Support of Invention Education) in 2017. Second, the above three policies can be divided into four periods of elementary and secondary invention education policy in Korea: 1) Introduction period (1973∼1994), 2) Growth period (1995∼2006), 3) Diffusion period (2007∼2016), and 4) Maturity period (2017∼).

시뮬레이션 활용 자율주행 성능 평가를 위한 운전자 모델 기반 교통류 시나리오 생성

문대영(Daeyoung Moon),전승민(Seungmin Jeon),이기범(Kibeom Lee) 한국자동차공학회 2023 한국자동차공학회 학술대회 및 전시회 Vol.2023 No.11

Effects of r-plane Sapphire Substrate Tilt Angles on the Growth Behavior of Nonpolar a-plane GaN

Park, Sung Hyun,Park, Jinsub,Moon, Daeyoung,Kim, Namhyuk,You, Duck-Jae,Kim, Junghwan,Kang, Jinki,Lee, Sang-Moon,Kim, Ju-Sung,Yang, Moon-Seung,Kim, Taek,Yoon, Euijoon Korean Physical Society 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.4

실업계 고등학교 학생의 대학 '동일계열 정원 외 특별전형' 운영 방안

문대영,류창열 충남대학교 공업교육연구소 2002 論文集 Vol.25 No.1

The purpose of this study was to propose a plan to enforce the special admission system of same majors' for vocational high school students. To perfom this study, questionnaire method was used and the data were collected by mail. The return rate were 62.6%(vocational high school ), 51.3%(college), and 48.1%(university) respectively. The statistical techniques used for data analysis was descriptive statistics like as frequency distribution, mean and standard deviation. The major findings in this study were as follows: 1)Qualification for application and standard of admission as a plan to enforce the special admission system of same majors were proposed. 2)Some problems as lack of ability to study, abnormal management of curriculum, confusion of range about some majors, and the validity of admission were drawn out. 3)Some alternative proposal as intensification of records in school, strengthen of accomplishment test in special subject, open and share of information about range of same majors, and introduce monitoring system were proposed.

Energy Efficient Hybrid Relay Transmission Scheme for Multiple Hop Mobile Networks

Daeyoung Lee,Jong-Moon Chung,Seungjun Choi 대한전자공학회 2010 ICEIC:International Conference on Electronics, Inf Vol.1 No.1

In this paper, we investigate the energy consumption of mobile multi-hop relaying systems in downlink transmission with and without relay station (RS) support. First we analyze the required transmission power of a base station (BS) in single-hop direct communication and then analyze the required power of a RS in a two-hop relaying topology, where for both cases, the constraint that the end-to-end data rate must be guaranteed has been applied in the derivations. Furthermore, an optimal hybrid RS selection scheme is proposed in this paper, which can determine if relying should be used or not, and if relaying is used then which RS will result in the best performance. The experimental results demonstrate that in terms of energy consumption performance (when applicable) the proposed hybrid mode, which uses both direct transmission and a two-hop relay transmission, out performs the one-hop direct transmission scheme.

Differential Tumorigenic Effects by C-Myc Mutants in Liver Cancer

( Daeyoung Kim ),( Hyuk Moon ),( Sook In Chung ),( Simon W. Ro ),( Kwang-hyub Han ) 대한간학회 2016 춘·추계 학술대회 (KASL) Vol.2016 No.1

Aims: Liver cancer is a major health concern worldwide, ranking third in terms of cancer-related mortality. The c-Myc gene is epigenetically altered in almost 50% of human liver cancers, leading to persistent over-expression of cMyc. In addition to quantitative changes of cMyc protein in cancers, mutation leading to amino acid substitution of cMyc has been found in a certain type of cancers. In this study, we compared tumorigenic potentials among c-Myc mutants in the liver. Methods: Transgenic liver cancer mouse models expressing different c-Myc mutants were developed using hydrodynamic transfection. Transposon vectors encoding the wild-type c-Myc, c-MycT58A, and c-MycS71F were constructed. To induce liver cancer, 20 μg of transposons were mixed with plasmids expressing the Sleeping Beauty transposase and then diluted in 2.5 ml of 0.9% saline. The DNA mixtures were injected into the lateral tail veins of 6-week-old C57BL/6 mice. Mice were monitored at least twice per week and sacrificed when moribund. Tumor-bearing livers were formalin fixed for hematoxylin- eosin staining. Results: Hepatocellular carcinomas (HCC) were induced by the stable expression of c-Myc and shp53. Wild type c-Myc was less tumorigenic than c-Myc2T58A or c-Myc2S71F when co-expressed with shp53. The c-Myc mutant groups, c-Myc2T58A or c-Myc2S71F died earlier than the c-Myc wild type group (p< 0.05). There was no difference in phenotypes of malignant hepatocytes among tumors induced by cMyc mutants and wild-type. Conclusions: Co-expression of c-Myc and shp53 in the mouse liver promoted hepatocarcinogenesis. Wild type c-Myc was less tumorigenic than c-Myc2T58A or c-Myc2S71F under the condition that P53 was down-regulated.

Enhancements to FPMIPv6 for improved seamless vertical handover between LTE and heterogeneous access networks

Jong-Moon Chung,Daeyoung Lee,Song, W. J.,Sungho Choi,Chaegwon Lim,Taesun Yeoum IEEE 2013 IEEE wireless communications Vol.20 No.3

<P>Fast handovers for proxy mobile IPv6 (FPMIPv6) was created to reduce packet-delay that occurs during proxy mobile IPv6 (PMIPv6) handover. Based on vertical handover (VHO) experiments conducted between Long Term Evolution (LTE) and heterogeneous accesses over the evolved packet core (EPC) using FPMIPv6, it was recognized that consistently reliable seamless VHO operations were difficult to accomplish due to limitations in FPMIPv6. Noticeably, VHO performance degradation resulted from the serving network (SN) lacking information of the target network (TN) when the TN is a heterogeneous protocol domain, packet congestion and loss problems occurring on specific network gateway interfaces, and also from using long packet-forwarding paths. In this article, an enhanced FPMIPv6 technique is proposed to solve these problems and improve the VHO operation by using shorter data-paths and improved coordination of buffered packet-forwarding and TN switching, which results in a significantly reduced packet-delay.</P>