Improvement of fill factor in pinhole-type integral imaging display using a retroreflector

Choi, Sungwon,Takashima, Yuzuru,Min, Sung-Wook The Optical Society 2017 Optics express Vol.25 No.26

Letter : Retrieval of background surface reflectance with pre-running BRD components

( Sungwon Choi ),( Chang Suk Lee ),( Minji Seo ),( Noh Hun Seong ),( Kyeong Sang Lee ),( Kyung Soo Han ) 대한원격탐사학회 2016 大韓遠隔探査學會誌 Vol.32 No.1

Importance of remote sensing for surface is increased than past. So many countries try to many ways to retrieve surface reflectance. In this study, we study a Bidirectional Reflectance Distribution Function (BRDF) to retrieve surface reflectance. We apply BRDF using observed surface reflectance of SPOT/ VEGETATION (VGT-S1) and angular data to get Bidirectional Reflectance Distribution (BRD) coefficients for calculating scattering. And then we apply BRDF in the opposite direction with BRD coefficients and angular data to retrieve Background Surface Reflectance (BSR). The range of BSR is not over 0.4 μm (blue), 0.45 μm (red), 0.55 μm (NIR). And for validation we compare BSR with VGT-S1, there are bias is from 0.0116 to 0.0158 and RMSE is from 0.0459 to 0.0545. As a result, we confirm that BSR is similar to VGT-S1.

Depth estimation method using depth-of-field imaging with a retroreflector

Choi, Sungwon,Min, Sung-wook The Optical Society 2018 Optics express Vol.26 No.5

Analysis of structural defects in MFI membranes by Fluorescene Confocal Optical Microscopy

Sungwon Hong,Jungkyu Choi,Dongjae Kim,Nakwon Choi,Jaewook Nam 한국막학회 2017 한국막학회 총회 및 학술발표회 Vol.2017 No.05

Defects of zeolite membranes often lower their separation performance. Thus, the investigation of the defects is highly critical in achieving high separation performance. While general characterization methods (e.g. scanning electron microscopy; SEM) that examine the membrane surface cannot detect defects, the FCOM measurement is able to identify the defective structure inside the zeolite membrane using dye molecules of appropriate size [1]. In this work, various dyeing conditions (times and concentrations) were applied to a MFI zeolite membrane in an attempt to investigate the defective structure. Furthermore, the quantitative analysis is practiced to measure the defects in numerical form.

Common occurrence of internal repeat symmetry in membrane proteins

Choi, Sungwon,Jeon, Jouhyun,Yang, Jae-Seong,Kim, Sanguk Wiley Subscription Services, Inc., A Wiley Company 2008 Proteins Vol.71 No.1

<P>Symmetry plays significant roles in protein structure and function. Particularly, symmetric interfaces are known to act as switches for two-state conformational change. Membrane proteins often undergo two-state conformational change during the transport process of ion channels or the active/inactive transitions in receptors. Here, we provide the first comprehensive analyses of internal repeat symmetry in membrane proteins. We examined the known membrane protein structures and found that, remarkably, nearly half of them have internal repeat symmetry. Moreover, we found that the conserved cores of these internal repeats are positioned at the interface of symmetric units when they are mapped on structures. Because of the large sequence divergence that occurs between internal repeats, the inherent symmetry present in protein sequences often has only been detected after structure determination. We therefore developed a sensitive procedure to predict the internal repeat symmetry from sequence information and identified 4653 proteins that are likely to have internal repeat symmetry. Proteins 2008. © 2007 Wiley-Liss, Inc.</P>

Comparison of Land Surface Temperature Algorithm Using Landsat-8 Data for South Korea

( Sungwon Choi ),( Kyeong-sang Lee ),( Minji Seo ),( Noh-hun Seong ),( Donghyun Jin ),( Daeseong Jung ),( Suyoung Sim ),( Im Gook Jung ),( Kyung-soo Han ) 대한원격탐사학회 2021 大韓遠隔探査學會誌 Vol.37 No.1

Land Surface Temperature (LST) is the radiological surface temperature which observed by satellite. It is very important factor to estimate condition of the Earth such as Global warming and Heat island. For these reasons, many countries operate their own satellite to observe the Earth condition. South Korea has many landcovers such as forest, crop land, urban. Therefore, if we want to retrieve accurate LST, we would use high-resolution satellite data. In this study, we made LSTs with 4 LST retrieval algorithms which are used widely with Landsat-8 data which has 30 m spatial resolution. We retrieved LST using equations of Price, Becker et al. Prata, Coll et al. and they showed very similar spatial distribution. We validated 4 LSTs with Moderate resolution Imaging Spectroradiometer (MODIS) LST data to find the most suitable algorithm. As a result, every LST shows 2.160 ~ 3.387 K of RMSE. And LST by Prata algorithm show the lowest RMSE than others. With this validation result, we choose LST by Prata algorithm as the most suitable LST to South Korea.

자기주도적 윤리실천으로서의 대학생 무감독 시험제도 적용 사례에 관한 연구

최송욱(Choi, Songuk),최성원(Choi, Sungwon) 학습자중심교과교육학회 2016 학습자중심교과교육연구 Vol.16 No.5

본 연구는 자기주도 학습적 측면에서 본 대학 내 무감독 시험제도의 실천적 적용 방안에 관해 고찰하였다. 데이터의 수집과 분석에는 총 8개월이 소요되었으며, 포커스 그룹으로 참여한 총 15명의 학생이 전공 수업 중 10주에 걸쳐 반복측정을 동반한 quasi 디자인 형식의 실험에 참여하였고 학기 종료 후 5개월 뒤 다시 follow-up 연구에 참여하였다. 연구결과, 학생들은 무감독 시험을 경험해보는 것만으로도 이 제도에 대해 보다 높은 신뢰감과 만족도를 느끼게 되는 것으로 평가되었다. 또한 교수자가 이 제도의 도덕적 의의에 관해 학생들과 적극적으로 의사소통하고, 만약의 부정행위 시도에 대한 예방적 조치를 선제적으로 취했을 때 이 제도를 보다 공정하다고 인식하는 것으로 분석되었다. 이러한 연구 결과를 중심으로 대학생들에 대한 자기주도적 윤리실천으로서의 무감독 시험제도의 가능성에 관한 논의를 담았다. This study aims to investigate how to build an ethically successful and student self-directed implementation plan to conduct unproctored exams in college classroom settings. We employed ten-week long longitudinal quasi-experimental design with repeated measures for fifteen business-majoring students who were participated in a focus group of the study and a follow-up survey conducted five months later. The results show that the experience of participating in unproctored exams enhances students’ trust and satisfaction on unproctored style exams. Moreover, students’ perceived level of fairness also increases when the moral meaning of unproctored exam is actively communicated to students and when a practical way of cheating prevention is implemented in class. Ethical and educational implications and future research directions were discussed.

냉방기류가 이동식부탄연소기 사용에 미치는 영향에 대한 실증 연구

최성원(Choi Sungwon),오동석(Oh Dongseok),김완구(Kim Wankoo),이준희(Lee Junhee),남성현(Nam Sunghyun),이철우(Lee Chulwoo) 한국가스학회 2023 한국가스학회 학술대회논문집 Vol.2023 No.5

Organosilicate compound filler to increase the mechanical strength of superhydrophilic layer-by-layer assembled film

Jung, Sungwon,Park, Sohyeon,Choi, Woojin,Heo, Jiwoong,Kwon, Jaesung,Choi, Sunghwan,Hong, Jinkee Elsevier 2020 Journal of industrial and engineering chemistry Vol.84 No.-

<P><B>Abstract</B></P> <P>Technologies that can overcome the poor mechanical properties of the coatings with bacterial anti-adhesion effect based on super-wetting properties are still challenging. In this study, we developed a durable superhydrophilic nanocomposite coatings composed of polysaccharide matrix and organosilicate (OS) compound filler. In brief, carboxymethylcellulose (CMC) and chitosan (CS)-based multilayer films were fabricated via Layer-by-layer (LbL) assembly then crosslinking for the films was performed to improve inner stability and induce superhydrophilicity. As second step, we synthesized a biocompatible and robust organosilicate compound via sol-gel reaction and incorporate it as reinforcing filler into the superhydrophilic films. Consequently, durable hybrid superhydrophilic nanocomposites were coated on the substrate, and various chemical analysis and performance evaluations of the coatings were performed. The mechanical properties of the composite coatings were significantly improved due to the OS acting as a reinforcing filler in the multilayer films. Furthermore, the coatings exhibited excellent biocompatibility and transparency and exerted antibacterial effect based on superhydrophilic property. This study presents a practical strategy to solve the poor durability, the limitation of super-wetting coatings widely applied in various fields.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

성적평가에 대한 대학생 감정노동이 학업소진에 미치는 영향 연구

최송욱(Choi Songuk),최성원(Choi Sungwon) 학습자중심교과교육학회 2022 학습자중심교과교육연구 Vol.22 No.4

목적 본 연구는 대학 내 성적평가에 대한 대학생들의 공정성 인식이 학생들의 교수자에 대한 감정노동과 학업소진에 끼치는 영향을 고찰하였다. 방법 총 229명의 대학생이 학기말 3주간 1회에 걸쳐 온라인 설문에 참여하였으며 신뢰도 분석, 다층적 회귀분석 및 SPSS 부트스트래핑 매크로를 활용한 매개효과 분석이 이루어졌다. 결과 대학 내 성적평가에 대해 불공정하다고 인식하고 있는 학생들은 더 큰 학업소진을 경험하고 있었다. 또한, 그 과정에서 대학생들은 성적평가의 불공정성에 대한 불만과 좌절감의 표현을 되도록 억제하고 인상관리 차원에서 교수자에게 공손하고 정중한 태도를 보이는 감정노동을 하고 있었다. 성적 불공정성 인식과 학업소진 관계에 대한 감정노동의 매개효과를 부트스트래핑 기법으로 검증한 결과, 내면연기 보다는 표면연기를 통해 보다 더 유의한 매개효과가 드러났다. 결론 이는 대학 내 교수자들의 성적 및 성과평가에 대한 공정성 증진을 통해 대학생들의 학업소진을 감소시킬 수 있으며 특히 표면연기를 통한 감정노동의 감소가 주요함을 시사한다. 이에 대학 내 성적평가의 공정성 및 감정노동과 학업소진에 대한 시사점과 향후 연구 방향을 다루었다. Objectives This study investigates the impact of students’ justice perception of performance evaluation on academic burnout and emotional labor toward college instructors. Methods There are 229 volunteers from a college who completed the survey in three weeks. Reliability testing, hierarchical regression, and bootstrapping analyses using SPSS macro were conducted to find the mediation effect of emotional labor between justice perception and burnout. Results The results sho that students’ perception of unfairness of performance evaluation increase students’ academic burnout. Students’ level of emotional labor mediates the relationship between their unfairness perception and burnout, such that the major mediating effect unfolds through surface acting rather than deep acting. Conclusions College students perceiving unfairness on their performance evaluation tend to perform surface acting, therefore experience more burnout in their academic life. Implications and future research directions are suggested.