온라인 강의 참관을 통한 한국어교육 전공생들의 현장 경험 인식 연구

노채환 ( Roh¸ Chaehwan ),송은정 ( Song¸ Eunjung ),안정민 ( Ahn¸ Jeongmin ) 한국외국어대학교 외국어교육연구소 2021 외국어교육연구 Vol.35 No.3

본 연구에서는 ‘COVID-19’로 인해 대면 강의 참관이 물리적으로 어려운 상황에서 한국어교육 전공자들이 온라인 동영상 강의 참관을 통해서 강의 참관의 목표를 달성할 수 있는지 살펴보고자 하였다. 이를 위해 본 연구에서는 서울 소재 사이버대학에서 한국어교육 실습 교과목 내 온라인 동영상 강의 참관을 통해 강의 참관을 한 수강생들을 대상으로 설문조사를 실시하여 온라인 동영상 강의 참관에 대한 한국어교육 전공자들의 인식을 살펴보았다. 설문조사 분석 결과, 수강생들은 동영상 참관 프로그램에 대해 비교적 긍정적인 인식을 가지고 있음을 알 수 있었다. 또한, 강의 참관 만족도는 수업 몰입도와 프로그램의 질과 강한 상관관계를 보였고, 프로그램의 질과 수업 몰입도, 인터페이스와 프로그램의 질 사이에서도 중간 강도의 상관관계를 보였다. 강의 참관 만족도에 어떤 요소가 영향을 끼치는지를 확인하기 위해 실시한 회귀분석 결과를 살펴보면 수업 몰입도와 프로그램의 질이 참관 수업 만족도에 유의미한 영향을 끼치고 있었다. 본고에서는 온라인으로 실시된 동영상 강의 참관에 대한 학습자의 인식을 조사하고, 이를 바탕으로 동영상 강의 참관의 개선점에 대하여 논하였다. 또, 각 요소들의 관계를 조사함으로써 강의 참관 활용과 개선을 위한 활용점을 찾고자 하였다. In this study, we tried to examine whether Korean language education majors can achieve the goal of class observation by observing VOD of face-to-face classes in a situation where it is physically difficult to observe face-to-face lectures due to 'COVID-19'. To this end, in this study, a survey was conducted on students who observed VOD in Korean language education practice courses at Cyber University in Seoul to examine the perceptions of Korean language education majors about observing VOD of face-to-face classes. As a result of the survey analysis, it was found that the students had a relatively positive perception of the online VOD observation. In addition, the observed class satisfaction showed a strong correlation with class immersion and program quality, and showed a moderate correlation between program quality and class immersion, and interface and program quality. The results of the regression analysis conducted to check which factors affect the satisfaction of the class observation program showed that the class immersion and the quality of the program had a significant effect on the satisfaction of the program. In this paper, we investigated learners' perceptions of online VOD observations, and based on this, we discussed the improvement points of the program. In addition, by examining the relationship between each element, it was attempted to find useful points for the utilization and improvement of the class observation.

비실시간 온라인 한국어 수업에 대한 학습자 인식 연구

노채환 ( Roh¸ Chae-hwan ) 반교어문학회 2020 泮橋語文硏究 Vol.0 No.56

본 연구는 COVID-19에 의해 야기된 교육 혁신의 변화 요구가 위기가 아닌 기회가 될 수 있다는 관점에서 비대면 비실시간 온라인 한국어 수업에 대한 학습자 인식을 살펴보았다. 이를 위해 온라인 한국어 수업을 수강하는 외국인 학습자들을 대상으로 설문 조사를 실시하여 온라인 수업과 온라인 수업 환경, 온라인 수업을 통한 학습 집중과 몰입, 온라인 수업에서의 상호작용에 대한 인식을 알아보았다. 학습자들의 응답을 토대로 조사 결과를 분석하고 이를 바탕으로 비대면 비실시간 온라인 한국어 교육이 나아가야 할 방향과 더불어 교육적 함의를 제시하여 향후 온라인을 통한 한국어교육을 준비하고 실시하는 데 활용될 수 있도록 하였다. This study examined learners' perception of non-face-to-face, non-real-time online Korean language classes from the perspective that the demand for change in education innovation caused by COVID-19 could be an opportunity rather than a crisis. To this end, a survey was conducted on foreign learners taking online Korean classes to find out their perceptions of online classes and online class environments, learning concentration and immersion through online classes, and interactions in online classes. Based on the responses of learners, the survey results were analyzed, and based on this, the direction for the non-face-to-face, non-real-time online Korean language education was suggested as well as educational implications. It could be used to prepare and conduct Korean language education through online in the future.

Low Carbon Nylon Materials Development

Chaehwan Hong(홍채환) 한국고분자학회 2023 한국고분자학회 학술대회 연구논문 초록집 Vol.48 No.1

Detection of Apnea Signal using UWB Radar based on Short-Time-Fourier-Transform

Chaehwan Hwang(황채환),Suyeol Kim(김수열),Deokwoo Lee(이덕우) 한국산학기술학회 2019 한국산학기술학회논문지 Vol.20 No.7

최근 비침투 또는 비접촉 방식을 활용한 호흡상태 관찰에 대한 관심이 높아지고 있다. 여러 가지 많은 생체신호들중 호흡신호를 활용하여 건강상태를 점검하는 것은 비정상적인 건강 상태에 대한 신속한 대응을 가능하게 해 준다. 본 논문에서는 국소 퓨리에 변환을 활용한 실시간 무호흡 상태 검출에 대한 방법을 제시한다. 기존의 고속 퓨리에 변환을 활용한 신호해석과 달리, 본 논문에서는 국소 퓨리에 변환을 사용하여 짧은 신호 구간에서의 주파수 응답을 분석한다. 본 연구에서 호흡 신호는 비접촉 방식을 활용하였으며, 초광대역 레이더 모듈을 활용하여 신호를 획득하였다. 국소 퓨리에 변환을 활용하여 호흡 상태를 검출한 후, 검출 결과에 따라 호흡 상태에 대한 분류가 가능하다. 특히 국소 퓨리에 변환은 실시간으로 호흡 상태에 대한 주파수 분석이 가능하도록 하였다. 호흡신호에 잡음이 존재할 경우를 대비하여 적절한 필터링 알고리즘이 적용되었다. 본 논문에서 제안하는 방법은 직관적으로 구현이 가능하고, 실질적으로 사람의 호흡상태에 대한 분석이 가능하도록 해준다. 제안한 방법을 검증하기 위해 호흡신호를 활용한 실험결과를 제시한다. Recently, monitoring respiration of people has been of interest using non-invasive method. Among the vital signals usually used for indicating health status, non-invasive and portable device based monitoring respiratory status is practically useful and enable one to promptly deal with abnormal physical status. This paper proposes the approach to real-time detection of apnea signal based on Short-Time-Fourier-Transform(STFT). Contrary to the analysis of a signal in frequency domain using Fast-Fourier Transform, this paper employs Short-time-Fourier-Transform so that frequency response can be analyzed in short time interval. The respiratory signal is acquired using UWB radar sensor that enables one to obtain respiration signal in contactless way. Detection of respiratory status is carried out by analyzing frequency response, and classification of respiratory status can be provided. In particular, STFT is employed to analyze respiratory signal in real-time, leading to effective analysis of the respiratory status in practice. In the case of existence of noise in the signal, appropriate filtering process is employed as well. The proposed method is straightforward and is workable in practice to analyze the respiratory status of people. To evaluate the proposed method, experimental results are provided.

Characterizations of i-a-Si:H and p-a-SiC:H Film using ICP-CVD Method to the Fabrication of Large-area Heterojunction Silicon Solar Cells

Chaehwan Jeong,Minsung Jeon,Koichi Kamisako 한국전기전자재료학회 2008 Transactions on Electrical and Electronic Material Vol.9 No.2

We investigated for comparison of large-area i-a-Si:H and p-a-SiC:H film quality like thickness uniformity, optical bandgap and surface roughness using both ICP-CVD and PECVD on the large-area substrate(diameter of 100 mm). As a whole, films using ICP-CVD could be achieved much uniform thickness and bandgap of that using PECVD. For i-a-Si:H films, its uniformity of thickness and optical bandgap were 2.8 % and 0.38 %, respectively. Also, thickness and optical bandgap of p-a-SiC:H films using ICP-CVD could be obtained at 1.8 % and 0.3 %, respectively. In case of surface roughness, average surface roughness (below 5 nm) of ICP-CVD film could be much better than that (below 30 nm) of PECVD film. HIT solar cell with 2 wt%-AZO/p-a-SiC:H/i-a-Si:H/c-Si/Ag structure was fabricated and characterized with diameter of 152.3 mm in this large-area ICP-CVD system. Conversion efficiency of 9.123 % was achieved with a practical area of 100 mm ´ 100 mm, which can show the potential to fabrication of the large-area solar cell using ICP- CVD method.

Markov Decision Process-based Potential Field Technique for UAV Planning

CHAEHWAN MOON,안재명 한국산업응용수학회 2021 Journal of the Korean Society for Industrial and A Vol.25 No.4

This study proposes a methodology for mission/path planning of an unmanned aerial vehicle (UAV) using an artificial potential field with the Markov Decision Process (MDP). The planning problem is formulated as an MDP. A low-resolution solution of the MDP is obtained and used to define an artificial potential field, which provides a continuous UAV mission plan. A numerical case study is conducted to demonstrate the validity of the proposed technique.

Peptide-tethered Electrochemical Biosensor for The Detection of Neutrophil Gelatinase-Associated Lipocalin (NGAL)

CHAEHWAN CHO,JIHONG KIM,MYUNGYI RYU,JONGPIL PARK 한국생물공학회 2019 한국생물공학회 학술대회 Vol.2019 No.4

The Role of Extracellular Vesicles in Senescence

Chaehwan Oh,Dahyeon Koh,Hyeong Bin Jeon,Kyoung Mi Kim 한국분자세포생물학회 2022 Molecules and cells Vol.45 No.9

Cells can communicate in a variety of ways, such as by contacting each other or by secreting certain factors. Recently, extracellular vesicles (EVs) have been proposed to be mediators of cell communication. EVs are small vesicles with a lipid bilayer membrane that are secreted by cells and contain DNA, RNAs, lipids, and proteins. These EVs are secreted from various cell types and can migrate and be internalized by recipient cells that are the same or different than those that secrete them. EVs harboring various components are involved in regulating gene expression in recipient cells. These EVs may also play important roles in the senescence of cells and the accumulation of senescent cells in the body. Studies on the function of EVs in senescent cells and the mechanisms through which nonsenescent and senescent cells communicate through EVs are being actively conducted. Here, we summarize studies suggesting that EVs secreted from senescent cells can promote the senescence of other cells and that EVs secreted from nonsenescent cells can rejuvenate senescent cells. In addition, we discuss the functional components (proteins, RNAs, and other molecules) enclosed in EVs that enter recipient cells.

Investigation on the Texture Effect of RF Magnetron-Sputtered ZnO:Al Thin Films Etched by Using an ICP Etching Method for Heterojunction Si Solar Cell Applications

Chaehwan Jeong,Seongjae Boo,Ho-Sung Kim,Duck-Rye Chang,Minsung Jeon,Koichi Kamisako 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.1

The effect of the etching gas ratio (Cl2/Ar) and the RF chuck power for dry etching of deposited aluminum-doped zinc oxide (AZO) films was investigated. The initially smooth films showed optical transparencies (T ≥ 80 %) and electrical properties (ρ = 1.14 × 10-3 Ωcm). The etch rate increased gradually with higher RF chuck power and Cl2 gas ratio, reaching a value of ~1450 Å/min. The surface morphology, electrical properties and diffuse reflectance were examined in the etched samples. Heterojunction solar cells with a AZO/p-a-SiC:H/c-Si/Al structure simulated on a textured AZO film show the higher short-circuit current (15.8 mA/㎠) and a higher quantum efficiency (75 %) in the wavelength range of 400 ~ 1100 nm, demonstrating effective light trapping. These results show the potential of a textured layer etched by using ICP etching for solar cell applications. The effect of the etching gas ratio (Cl2/Ar) and the RF chuck power for dry etching of deposited aluminum-doped zinc oxide (AZO) films was investigated. The initially smooth films showed optical transparencies (T ≥ 80 %) and electrical properties (ρ = 1.14 × 10-3 Ωcm). The etch rate increased gradually with higher RF chuck power and Cl2 gas ratio, reaching a value of ~1450 Å/min. The surface morphology, electrical properties and diffuse reflectance were examined in the etched samples. Heterojunction solar cells with a AZO/p-a-SiC:H/c-Si/Al structure simulated on a textured AZO film show the higher short-circuit current (15.8 mA/㎠) and a higher quantum efficiency (75 %) in the wavelength range of 400 ~ 1100 nm, demonstrating effective light trapping. These results show the potential of a textured layer etched by using ICP etching for solar cell applications.

Characterization of Combined Micro- and Nano-structure Silicon Solar Cells using a POCl<SUB>3</SUB> Doping Process

Chaehwan Jeong,Changheon Kim,Jonghwan Lee,Junsin Yi,Sangwoo Lim,Suk-Ho Lee 한국태양광발전학회 2013 Current Photovoltaic Research Vol.1 No.1

Combined nano- and micro-wires (CNMWs) Si arrays were prepared using PR patterning and silver-assisted electroless etching. A POCl3 doping process was applied to the fabrication of CNMWs solar cells. KOH solution was used to remove bundles in CNMWs and the etching time was varied from 30 to 240 s. The lowest reflectance of 3.83% was obtained at KOH etching time of 30 s, but the highest carrier lifetime of 354 μs was observed after the doping process at 60 s. At the same etching time, a Voc of 574 mV, Jsc of 28.41 mA/cm<SUP>2</SUP>, FF of 74.4%, and Eff. of 12.2% were achieved in the CNMWs solar cell. CNMWs solar cells have potential for higher efficiency by improving the postprocess and surface-rear side structure.