Participation in the Einstein Telescope Collaboration

Sungho Lee,Chunglee Kim,Young-Sik Ra,Soojong Pak,Kyujin Kwak,June Gyu Park,Kyung-ha Lee,Kyungmin Kim,Young-Min Kim,Jinho Kim,Chang Hee Kim,Byeong-Yoon Go,Geunhee Gwak,Hojae Ahn,Sumin Lee,Kihyun Jung,S 한국천문학회 2023 天文學會報 Vol.48 No.2

Single-port laparoscopic repair of perforated duodenal ulcer : Intracoporeal "Cross and twine" knot

Sungho Lee,Dosang Lee,Jongman Won,Ilyoung Park,Kiyoung Sung,Junhyun Lee 대한외과학회 2010 대한외과학회 학술대회 초록집 Vol.2010 No.11

Procalcitonin as a Predictive Factor for the Clinical Outcome of Patients with Coronavirus Disease 2019

Sungho Lee,Lee Jung Mo,Choi Taeyang,Park Kwanhoon,Lee Kang Yoon,Ji Young Jang 대한외상중환자외과학회 2022 Journal of Acute Care Surgery Vol.12 No.2

Purpose: The coronavirus disease 2019 (COVID-19) pandemic continues. It has been reported that patients with bacterial coinfection have a higher mortality rate than patients without coinfection. However, there are no clear standard guidelines for the use of antibacterial drugs. Therefore, the purpose of this study was to determine the usefulness of procalcitonin, a specific indicator of bacterial infection, as a biomarker for predicting death in COVID-19 patients.Methods: This was a retrospective study of confirmed COVID-19 patients (<i>N</i> = 283) between December 2020 and February 2021 who survived or died. Logistic regression analysis was performed to determine whether there was an association between the level of procalcitonin and death. In addition, receiver operating characteristic curve analysis was performed to determine the usefulness of procalcitonin as a predictor of death.Results: In the non-survivor group, age, the number of patients transferred from a health care center, segment neutrophil ratio, C reactive protein, ferritin, and procalcitonin were significantly higher in the survivor group. In multivariate analysis, procalcitonin was identified as an independent factor associated with death (hazard ratio 6.162, confidential interval 2.285-26.322, <i>p</i> = 0.014). In addition, the predictive power of procalcitonin level and mortality was statistically significant using receiver operating characteristic curve analysis which gave an area under the curve value of 0.823, a cut-off value of 0.05, a sensitivity of 72.2%, a specificity of 87.5% (<i>p</i> < 0.001).Conclusion: Measurement of procalcitonin and other biomarkers may be useful to determine whether to use or discontinue use of antibacterial drugs in patients with COVID-19.

Analysis of Usability Evaluation for a Graphic User Interface

Sungho Kim,Baekhee Lee,Jihyung Lee,Jawon Lee,Soojung Lee,Kiwon Lee,Seikwon Park,Heecheon You 대한인간공학회 2014 대한인간공학회 학술대회논문집 Vol.2014 No.11

Objective: The present study is to establish a usability evaluation framework for graphic user interface (GUI). Background: Existing studies have mainly focused on specific GUI evaluation such as mobile applications and website; however, lacked of consideration with GUIs for a specialized field such as the military. Method: A four-step approach was applied in the study: (1) literature review of twenty studies related to usability evaluation, (2) analysis of GUI usability aspects by design component, design guideline/evaluation criterion, and evaluation method, (3) development of an integrated usability evaluation framework, and (4) application to screen GUIs of a computer based training (CBT). Results: Design component in the integrated usability evaluation framework was consisted of 40 design dimensions in 9 components (e.g., alignment in layout), design guideline/evaluation criterion 33 principles and guidelines (e.g., visibility), and evaluation method 38 measures (e.g., completion time) and 19 techniques (e.g., heuristic evaluation). Conclusion: The usability evaluation framework for GUI was developed in the study. Application: The usability evaluation framework for GUI can be applicable to a variety of GUIs (e.g., console screen) and utilized to evaluate GUIs systematically.

Self-Calibrated Two-Point Delta–Sigma Modulation Technique for RF Transmitters

Sungho Lee,Jaejun Lee,Hangue Park,Kang-Yoon Lee,Sangwook Nam IEEE 2010 IEEE transactions on microwave theory and techniqu Vol.58 No.7

<P>A self-calibrated two-point delta-sigma modulation technique for CMOS RF transmitter is proposed. This calibration technique employs voltage-controlled oscillator (VCO) and delta-sigma modulator input ports in a frequency synthesizer. By monitoring the control voltage of a loop filter, the gain mismatch between two paths can be detected and completely calibrated by modifying the gain of the VCO path. The acceptable timing mismatch between the two paths is also investigated so that the timing can be controlled to ensure stable output performance. As a result, the phase modulation guarantees a robust performance against PVT variations without using any predistortion techniques. This technique is applied to a quad-band (850/900/1800/1900) GSM/EDGE transmitter for verification. For the amplitude modulation of the EDGE mode, a dc calibration is adopted to suppress unwanted carrier leakage tones. The measurement results show satisfactory GSM/EDGE spectrums and error vector magnitude performance at both low- and high-frequency bands.</P>

Usability Evaluation of Graphic User Interfaces for a Military Computer-Based Training System

Sungho Kim,Soojung Lee,Kiwon Lee,Baekhee Lee,Jihyung Lee,Seikwon Park,Heecheon You 대한인간공학회 2015 大韓人間工學會誌 Vol.34 No.5

Objective: The present study was to improve the graphic user interface (GUI) of a military computer-based training (CBT) system in terms of usability. Background: Existing studies have focused on usability evaluation of a particular GUI type such as sequence, hierarchy, or context type; however, few research has been conducted which identifies preferred GUI features based on a comparative analysis of different GUI types. Method: A comparative evaluation was conducted by 9 CBT design experts using a 7-point scale (1: very low, 4: neutral, and 7: very high) on hierarchy and context GUI types of a military CBT system in terms of 10 usability criteria. Then, preferred features of the hierarchy and context types being accommodated, a new GUI was developed and validated by 22 CBT users. Results: While the hierarchy type was found preferred by 1.6 times in terms of controllability to the context type, the opposite was found in terms of attractiveness, simplicity, and responsiveness by 0.6, 0.8, and 0.8 times, respectively. The proposed GUI was found superior to the hierarchy and context types in terms of accessibility and informativeness by more than 1.5 times, but inferior to the hierarchy and context type in terms of simplicity by 0.6 and 0.9 times, respectively. Conclusion: The new GUI developed by accommodating the preferred features of the hierarchy and context types improves usability in terms of accessibility and informativeness except simplicity. Application: The comparative analysis of various GUIs can be applied to develop an improved GUI in a systematic manner based on preferred features of the existing GUIs.

Effects of drawing process on the structure and tensile properties of textile-grade PAN fiber and its carbon fiber

Lee, Hwayoung,Lee, Lo-Woon,Lee, Seung-Wook,Joh, Han-Ik,Jo, Seong-Mu,Lee, Sungho Walter de Gruyter GmbH 2014 E-Polymers Vol.14 No.3

<B>Abstract</B><P>Carbon fibers (CFs) were prepared using low-cost, textile-grade polyacrylonitrile fibers, which were 200% to 400% drawn in a hot water bath at 90°C or/and in a tubular furnace at 180°C. X-ray diffractograms confirmed that the drawing process led to higher crystallinity and molecular orientation. These fibers were stabilized in a convection oven at 25-255°C for 390 min. After stabilization, carbonization was performed to obtain carbon fibers. The tensile strength of CFs without drawing was ∼0.8 GPa; however, CFs with 200% and 200% drawing in a hot water bath at 90°C and in a tubular furnace at 180°C, respectively, showed a tensile strength of ∼1.7 GPa. These results suggest that the drawing process of precursor fibers affected the tensile properties of the resulting CFs significantly.</P>

자율주행 센서 세척 평가를 위한 먼지의 성능 비교 연구

손성호(SungHo Son),이웅수(WoogSu Lee),정현기(HyunGi Jung),이장민(JangMin Lee),김자륭(ChaRyung Kim),이현우(HyunWoo Lee),박형원(HyungWon Park),이정기(JungKi Lee) 한국자동차공학회 2023 한국자동차공학회 부문종합 학술대회 Vol.2023 No.5

관계적 교사행위자성 개념모형에 근거한 교사 간 ‘관계재’ 조사 문항 개발 및 타당화 연구

이성회(Lee, Sunghoe),이호준(Lee, Hojun) 한국교원교육학회 2022 한국교원교육연구 Vol.39 No.1

이 연구의 목적은 교사 간 관계재를 측정할 수 있는 문항을 개발하고, 예비조사를 통해 개발한 문항의 신뢰도와 타당도를 검증하는 데 있다. 이를 위해 비판적 실재론에 기반한 ‘관계적 교사행위자성’ 개념모형(이성회 외, 2021)에 근거하여 ‘교사 관계구조’, ‘관계적 상호작용’, ‘개인적 성찰’, ‘관계적 성찰’, ‘우리의 형성’, ‘발현적 효과’를 관계재 측정의 핵심 요소로 도출한 후 50개 관계재 조사 문항을 개발하였다. A 교육청 산하 고등학교에서 근무하는 220명의 교사를 대상으로 예비조사를 실시하고, Cronbach α, 탐색적 요인분석, 확인적 요인분석을 활용해 관계재 조사 문항의 신뢰도와 타당도를 검토하였다. 교사 간 관계재 측정도구는 비판적 실재론이라는 견실한 사회과학철학을 토대로 한 관계사회학 관점에서 사회적 관계를 상징적 참조, 구조적 연대, 발현적 효과란 세 가지 의미론으로 통합적으로 개념화해 이를 문항에 반영하였다는 점에서 이론적 의의가 있다. 아울러 관계구조를 분석하기 위한 연구방법론적 도구로서의 AGIL 도식은 그간 선행연구에서 도외시되었던 관계의 질적 속성을 목적, 가치, 규범, 수단이라는 구체화된 유목화된 문항을 통해 확인할 수 있도록 했다는 점에서 방법론적 가치를 지닌다. 또한, 사회적 관계를 ‘발현적인 독자적 실재’로 개념화함으로써 개인 아니면 체제란 이분법적 담론을 넘어서서 독립적 분석단위로서의 관계(구조)에 대한 새로운 시선을 담은 교사 관계 측정도구 개발의 단초를 제공해주었다는 점에서 그 의미를 지닌다. The purpose of this study is to develop items that measure relational goods amongst school teachers and to verify the reliability and validity of the developed items. To this end, this study developed 50 measurement items based on the conceptual model of ‘Relational Teacher Agency(hereafter, RTA)’ presented by Lee et al.(2021). To examine the reliability and the validity of the developed items, a preliminary survey was conducted targeting 220 teachers working in general high schools and specialized high schools affiliated with the A Office of Education. This research employed Cronbach α, Exploratory Factor Analysis, and Confirmatory Factor Analysis to verify the reliability and the validity of measurement items concerning relational goods. As a result, 41 items were finalized as relational goods measurement items according to RTA model. Theoretically, this study is meaningful in that it conceptualizes social relations as three semantics of symbolic reference(refero), structural bond(religo) and emergent effect from the perspective of critical realist relational sociology(hereafter, CRRS) and utilizes them in the relational goods questionnaire. In addition, the AGIL as a compass for analyzing the relational structure conveys methodological value in that it enables to explore the qualitative properties of social relationships, which have been mostly neglected in the existing literature. Finally, this study is significant in that it paves a way for developing a relational goods questionnaire based on a relational gaze by conceptualizing social relationships as an siu generis reality based on CRRS.

Effect of pre-annealing on chemical configuration and heteroatom doping of highly active carbon catalysts for the oxygen reduction reaction

Hae Ri Lee,Seunggyun Han,Jong Yoon Lee,Gwanwon Lee,Sungho Lee,Han-Ik Joh 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.128 No.-

Heteroatom-doped carbon catalysts are promising alternatives to platinum group metal-free catalysts foroxygen reduction reaction (ORR). To enhance the ORR activity of carbon-based catalysts, the break ofelectroneutrality and number of active sites must be maximized. In this study, an annealing process ata mild temperature was introduced before heteroatom doping to control the content and configurationof the oxygen functional groups on the graphene oxide (GO). Pre-annealing affects the chemical configurationand the porosity of GO such that the epoxy groups are converted into carbonyl groups accompanyingthe defect formation. Interestingly, The carbonyl-enriched environment allowed ammonia borane,as a dopant with nitrogen and boron atoms, the enhanced doping performance, inducing the formation ofhigher number of heteroatom doping sites and additional defects in the graphene lattice. The aBNG-150catalyst demonstrated outstanding ORR activity in both half- and single-cell evaluations because it hadthe highest heteroatom content and meso/macropores derived from the elimination of oxygen functionalgroups, which can facilitate ORR catalytic activity and O2 diffusion pathway. Therefore, we believe thatthis approach provides an effective route for synthesizing carbon-based catalysts with remarkable ORRperformances.