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온라인수업 환경에서 학습실재감이 학습몰입 및 만족도에 미치는 영향 - 호텔·관광전공 학생들을 중심으로 -
최상수 ( Choi¸ Sangsu ),이진영 ( Lee¸ Jinyoung ) 한국호텔리조트학회 2021 호텔리조트연구 Vol.20 No.5
The objective of this study is to verify the relations of learning presence, learning flow, and learning satisfaction in online education environment, and also to understand which factors of learning presence would have significant effects on learning flow and learning satisfaction. To achieve the objective of this study, a survey was conducted targeting the students majoring in hotel & tourism of three universities in Gangwon-do, Gyeonggi-do, and Chungcheongbuk-do for about a month from April 20th to June 18th 2021. After distributing total 180 questionnaires, total 151 questionnaires were used for the analysis by excluding 29 questionnaires with insincere responses. Using the SPSS.18.0 Program, the multiple regression analysis was conducted. In the results of the analysis, of the subfactors of learning presence, the cognitive presence and emotional presence had significantly positive(+) effects on the formation of learning flow and learning satisfaction of students while the social presence did not have significant effects on learning flow and learning satisfaction. Based on such results, this study aims to present the importance of learning presence in online.
Transient Engine Test Bed를 이용한 가솔린엔진의 F/E 및 Emission개선에 관한 연구
이상수(Sangsu Lee),이창준(Changjun Lee),이근봉(Keunbong Lee),이문식(Moonsig Lee),이정근(Jeongkeun Rhee) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The fuel economy and emissions in a developing port injection gasoline engine with manual transmission were studied using a transient engine test bed. Because the fuel economy and emissions in the first few minutes during engine warmup show great importance, the first ECE cycle in NEDC mode was simulated. To match the fuel economy and emission levels with the roller bed test results, driver model on clutch and acceleration pedal actions were thoroughly adjusted to match engine speed and engine load of the vehicle. The faster catalyst light-off was investigated by varying crank-to-run air-fuel ratio and idle spark timing. and results showed that slightly lean air fuel ratio was more effective in heating lip the catalyst than retarding idle spark timing in terms of fuel economy. The additional engine EMS calibrations were performed to improve cruise operation points and idle regions using DOE method with L9 orthogonal test array. The overall results showed that both the fuel economy and emissions were improved during first ECE cycle in the NEDC mode test by the EMS calibration performed in this study.
Dynamic Engine Test Bench를 이용한 가솔린 차량의 Emission Test에 관한 연구
이상수(Sangsu Lee),이근봉(Keunbong Lee),이문식(Moonsig Lee),김숭기(Soongkee Kim) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4
The fuel consumption and emissions from gasoline vehicle with MT and AT were tested using a dynamic engine test bench. The engine was dynamically controlled to simulate the dynamic behavior of engine inside the vehicle in motion. The variation of EMS data in vehicle such as engine speed, MAP and gear stage was closely reproduced with engine test bench by using inertia simulation and control software and found to reproduce fuel economy around ±1%, and emissions around ±10%. The forced soaking procedure, signal generator for TCU, realistic coolant temperature profile and idle MAP increased by dyno friction were tried for better correlation with vehicle data.
Lee, Wootae,Park, Jubong,Kim, Seonghyun,Woo, Jiyong,Shin, Jungho,Choi, Godeuni,Park, Sangsu,Lee, Daeseok,Cha, Euijun,Lee, Byoung Hun,Hwang, Hyunsang American Chemical Society 2012 ACS NANO Vol.6 No.9
<P>We demonstrate a high-performance selection device by utilizing the concept of crested oxide barrier to suppress the sneak current in bipolar resistive memory arrays. Using a TaO(x)/TiO(2)/TaO(x) structure, high current density over 10(7) A cm(-2) and excellent nonlinear characteristics up to 10(4) were successfully demonstrated. On the basis of the defect chemistry and SIMS depth profile result, we found that some Ta atoms gradually diffused into TiO(2) film, and consequently, the energy band of the TiO(2) film was symmetrically bent at the top and bottom TaO(x)/TiO(2) interfaces and modified as a crested oxide barrier. Furthermore, the one selector-one resistor device exhibited significant suppression of the leakage current, indicating excellent selector characteristics.</P>
Creepage Discharge Characteristics of Solid Insulation Materials for Superconducting Power Cable
Lee, Onyou,Jeong, Minkyung,Jeon, Sangsu,Lee, Hongseok,Hong, Jonggi,Kang, Hyoungku Institute of Electrical and Electronics Engineers 2018 IEEE transactions on applied superconductivity Vol.28 No.3
<P>Solid insulation materials need to be robust in terms of both mechanical and electrical performance for application in a high-voltage superconducting apparatus. It is known that creepage discharge characteristics of solid insulation materials are inferior to their electrical breakdown characteristics with penetration. Therefore, electrical breakdown accidents in a superconducting apparatus could occur as a form of creepage discharge rather than electrical breakdown with penetration. In this study, we conduct dielectric experiments on the penetration and creepage discharge characteristics of epoxy resin and polypropylene laminated paper under cryogenic temperature by using three kinds of electrode systems. The first is for creepage discharge experiments along the surfaces of solid insulation materials in liquid nitrogen. The second is for creepage discharge experiments across the interface between two different solid insulation materials making contact in liquid nitrogen. The third is for experiments of electrical breakdown with penetration on solid insulation materials in liquid nitrogen. Dielectric experiments are conducted with an absolute pressure of 0.1 MPa under alternating current and lightning impulse voltages. Experimental results for electrical breakdown characteristics of solid insulation materials with penetration are compared with the creepage discharge characteristics on the surface and interfaces between solid insulation materials. Moreover, the criteria for electric field intensities at creepage discharge voltages in various conditions are deduced as empirical formulas.</P>
Lee, Eun-Mee,Shin, Sangsu,Cha, Hwa Jun,Yoon, Youngmin,Bae, Seunghee,Jung, Jin Hyuk,Lee, Sun-Mi,Lee, Su-Jae,Park, In-Chul,Jin, Young-Woo,An, Sungkwan D.A. Spandidos 2009 INTERNATIONAL JOURNAL OF MOLECULAR MEDICINE Vol.24 No.1
<P>Suberoylanilide hydroxamic acid (SAHA) is a histone deacetylase inhibitor (HDACI) with antitumor effects that is being explored as a therapeutic drug. However, it has been reported that non-small cell lung cancer (NSCLC) is resistant to HDACIs. MicroRNAs (miRNAs) are a key class of small, non-coding RNA molecules that modulate post-transcriptional regulation of gene expression in multi-cellular organisms. miRNA expression patterns are involved in deregulation of gene expression in human lung cancer. Here we identified miRNA expression profile changes in response to SAHA treatment in the human lung carcinoma cell line A549. We also examined potential mRNA targets of SAHA-responsive miRNAs by using a target prediction program. Using microarray analysis, we found 64 miRNAs with >2-fold expression changes in SAHA-treated A549 cells. Among them, two unique miRNAs were altered in 2.5 microM SAHA-treated cells, 31 unique miRNAs were altered in 5.0 microM SAHA-treated cells and 31 miRNAs were altered with both doses. These miRNAs are predicted to have several target genes related to angiogenesis, apoptosis, chromatin modification, cell proliferation and differentiation. In conclusion, we have identified a unique set of miRNAs and their expression profiles that are influenced significantly by SAHA in the A549 NSCLC cell line model, which might provide useful information for understanding the anticancer mechanism of SAHA.</P>
Lee, Sangsu,Kim, Dongho American Chemical Society 2016 The Journal of physical chemistry A Vol.120 No.46
<P>Intramolecular charge transfer (ICT) processes in two-photon (TP) allowed states were investigated using three pyrene derivatives NI, N2C, and N2T, which have different molecular symmetry depending on the number and position of N,N-dimethylaniline donating substituents. On the basis of steady-state and nondegenerate two-photon absorption measurements, we investigated femtosecond transient absorption (TA) spectra by one-photon (OPE) and two-photon excitation (TPE). In the analysis of TA spectra, we discovered that the transfer rate from locally excited state to the ICT state by TPE is slower than that by OPE, indicating that the energy barrier between the TP and ICT states is higher than that between the one-photon (OP) allowed and ICT states. Furthermore, we demonstrated that ICT dynamics in a TP state are affected by molecular symmetry through the disappearance of stimulated emission from the locally excited state in the TA spectra of N2T obtained by TPE. We believe that our findings will provide fundamental information for a better understanding of excited-state ICT dynamics.</P>