• 천문학회보
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• 제41권2호
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• pp.36.1-36.1
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• 2016

This is a presentation of the paper published as Kimm et al. 2016, ApJ, 823, 52. We investigate the formation of metal-poor globular clusters (GCs) at the center of two dark matter halos with $Mhalo{\sim}4{\times}107Msun$ at z>10 using cosmological radiation-hydrodynamics simulations. We find that very compact (${\leq}1$ pc) and massive (${\sim}6{\times}105Msun$) clusters form rapidly when pristine gas collapses isothermally with the aid of efficient $Ly{\alpha}$ emission during the transition from molecular-cooling halos to atomic-cooling halos. Because the local free-fall time of dense star-forming gas is very short (${\ll}1Myr$), a large fraction of the collapsed gas is turned into stars before stellar feedback processes blow out the gas and shut down star formation. Although the early stage of star formation is limited to a small region of the central star-forming disk, we find that the disk quickly fragments due to metal enrichment from supernovae. Sub-clusters formed in the fragmented clouds eventually merge with the main cluster at the center. The simulated clusters closely resemble the local GCs in mass and size but show a metallicity spread that is much wider than found in the local GCs. We discuss a role of pre-enrichment by Pop III and II stars as a potential solution to the latter issue. Although not without shortcomings, it is encouraging that a naive blind (not tuned) cosmological simulation presents a possible channel for the formation of at least some massive GCs.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.536-539
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• 2002

In this paper, we developed the automatic optical fiber aligner by image processing and automatic loading system. Optical fiber is indispensable for optical communication systems that transmit large volumes of data at high speed, but super-precision technology in sub-micron units is required for optical axis adjustment, we have developed 6-axis micro stage system for I/O optical fiber arrays, the initial automatic aligning system/software for a input optical array by the image processing technique, fast I/O-synchronous aligning strategy, the automatic loading/unloading system and the automatic UV bonding mechanism. In order to adjust the alignment it used on PC based motion controller, a $10\mu\textrm{mm}$ repeat-detailed drawing of automatic loading system is developed by a primary line up for high detailed drawing. Also, at this researches used the image processing system and algorithm instead of the existing a primary hand-line up. and fiber input array and waveguide chip formed in line by automatic. Therefore, the developed and manufactured optical aligning system in this research fulfills the great role of support industry for major electronics manufacturers, telecommunications companies, universities, government agencies and other research institutions.

• 대한한방부인과학회지
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• 제19권1호
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• pp.1-13
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• 2006

Purpose : Polygonum cuspidatum extract is an oriental herb which has been used for uterine diseases. In this study, the effects of Polygonum cuspidatum extract were investigated on inducing growth inhibition and apoptosis of human uterine cervical carcinoma cells. Methods : Viability of Polygonum cuspidatum extract-induced ME-180 cells was measured by MTT assay. Apoptotic cells were visualized by EtBr/AcOr staining under fluorescent microscope. Nucleosomal DNA fragmentation was assayed by agarose gel electrophoresis. Cell cycle distribution and changes in mitochondrial membrane potential were observed by flow cytometry. Results : Polygonum cuspidatum extract induced ME-180 cell death in a dose- and time-dependent manner. In the cells treated with Pc, the population of cells at sub-G1 phase significantly increased, and the condensed nuclei, apoptotic bodies and nucleosome-sized DNA were detected. Moreover, reduction in mitochondrial membrane potential was detected. Conclusion : Polygonum cuspidatum extract inhibits the growth and proliferation of ME-180 cells by apoptotic induction and facilitates its activity initiated by depolarization of mitochondria.

• 복식문화연구
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• 제7권1호
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• pp.1-12
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• 1999

Analysis of Customer Characteristics on Environment-Friendly Clothing Products The purpose of this study is to analyze the characteristics of the environment-friendly customers in Korean fashion market. The study is analyzed through questionary paper to the domestic female group of more than or equal to age of twenty living in Seoul. The collected questionary paper is analyzed with SPSS/PC/sub +/ program and the method of statistical analysis used for this study is frequency analysis, factor analysis, cluster analysis, t-test, and crosstab analysis. The result of analysis of the characteristics of the environment -friendly customers involves the following: Firstly, there were no significant difference in the demographic characteristics between the environment-friendly customer group and non-environment-friendly customers group. Secondly, environment-friendly customers had more environmental programs, had seen and heard more environmental program through current news from TV, newspapers, and magazines, and had more interest in recycling or separated collecting of garbage, and been doing better recycling or separated collecting. These serial processes of research, have the meaning in confirming that segmented market for environment-friendly customers exists in the domestic fashion market, and these will not only set up the basis of research on the market of environment-friendly fashion product but also be able to contribute to propose future direction of research.

• 아동학회지
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• 제32권1호
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• pp.157-172
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• 2011

The purpose of this study was to investigate the effect of childcare teachers' ego-resilience and directors, co-workers and family's social support to childcare teachers' burnout. The participants in this study were 326 childcare teachers from Daejeon metropolitan city and Chungnam province. They responded to the 'Maslach Burnout Inventory', 'Ego-resilience Scale', and 'Social Support Scale'. The collected data were analyzed by t-test, one-way ANOVA, Pearson's productive correlation, stepwise multiple regression, Duncan test for post hoc test, Cronbach's ${\alpha}$ for reliability, and factor analysis for validity by SPSS PC program (18.0 version). The results were as follows; first, there were significant differences in childcare teachers' burnout scores in relation to the educational levels of childcare teachers, their working hours, children's number per class, and the ages of the children they teach. Second, there were significant negative correlations (r = -.11~-.62) among childcare teachers' ego-resilience, directors, teaching colleagues and family's social supports, and their levels of burnout. Finally, childcare teachers' ego-resilience and teaching colleagues' levels of social support helped explain about 43% the childcare teachers' burnout total scores and about 17~39% of their sub-scores.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2004년도 춘계학술대회 발표 논문집
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• pp.179-184
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• 2004

This paper is an overview of the experimental work using a Planar Magnetic Levitation Stage System structure proposed by Dr. Won-Jong Kim in his PhD thesis. Based on his results, we built an Experimental Test Stand (ETS), which enabled us to get accustomed with the new technology and to create new control structures and algorithms. The ETS is controlled by a powerful controller made of 4 DSPs mastered by a PC. This controller structure increases the controller bandwidth up to 10 kHz leading to a better emulation of an analog controller and leaving enough room for further development. Based on analyzing all the factors that can affect the performances of the system, we achieved a great accurate positioning performance of sub-nanometer RMS value.

• 한국항공우주학회지
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• 제34권2호
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• pp.101-105
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• 2006

과학기술위성 2호의 탑재 컴퓨터(OBC)의 EM 모델을 개발하고 기능 및 성능평가를 완료하였다. 과학기술위성 2호의 탑재 컴퓨터는 고성능 CPU를 탑재하여 처리 성능을 향상 시켰으며 중앙 집중식 통신구조를 가지도록 설계하여 위성 시스템 내부의 다른 서브 유닛들과 직접 통신하여 위성의 각종 서브장치들을 조정하도록 하였다. 탑재 컴퓨터에 사용되는 통신모듈, 시스템 감시회로, SEU(Single Event Upset)를 극복하기 위한 로직회로 등 각종 제어 회로들을 FPGA 내에 구현함으로써 소형화, 경량화 및 저 전력화를 추구하고 기술 집약화 하도록 하였다.

• 정보보호학회논문지
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• 제19권6호
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• pp.113-119
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• 2009

최근 국내는 전자정부 인터넷 뱅킹 포털 등 대부분의 웹 사이트에서 다양하고 동적인 온라인 서비스 제공을 위해 ActiveX Control을 개발 배포하고 있다. 하지만, 안전성이 검증되지 않은 ActiveX Control은 인터넷 사용자들에게 심각한 보안위협요소가 될 수 있다. 최근 이러한 취약한 ActiveX Control로 인한 해킹 사고가 급격히 증가되고 있음에도 불구하고, 개인 PC 보안의식에만 의존할 뿐 이에 대한 국가적인 보안정책이나 대책이 마련되어 있지 않다. 이에, 본 논문에서는 ActiveX Control 개발 배포 사용의 3가지 측면 모두에서 안전하고 효율적인 보안관리가 가능한 보안인증을 통한 ActiveX Control 보안관리 모델 설계를 위한 기술적 방법론을 제안하고자 한다.

• International Journal of Advanced Culture Technology
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• 제9권4호
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• pp.188-193
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• 2021

This is a group pretest-posttest design study that aim to evaluate the effect of self-reflection promotion program of nursing students. The subjects of this study were 42 first-year nursing students. The data was collected from October 5 to November 2, 2020. A questionnaire was used to measure self-reflection and self-efficacy. The self-reflection promotion program was operated for a total of 8 hours in 4 sessions over 4 weeks. Online lectures were conducted using books, movies, and art recommended by expert. The subjects could take lectures using their smartphones, laptops, desktops, and tablet PC. As a result of the study, self-reflection was significantly improved after intervention than before intervention (t=-2.594, p=.013). In the sub-items, self-exploration and self-understanding were statistically significantly improved (t=-2.527, p=.015; t=-2.471, p=.018). However, other-exploration and other-understanding were not statistically significant (t=-1.226, p=.227; t=-.758, p=.453). The self-efficacy of the subjects was not statistically significant (t=-.170, p=.866). In future research, it will be necessary to develop and verify specific teaching and learning methods utilizing various contents that can improve self-reflection for nursing students.

• 에너지공학
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• 제23권2호
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• pp.42-48
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• 2014

미분탄의 연소 또는 열분해 과정으로부터 발생하는 tar-soot는 복사 열전달 및 질소산화물의 추가적인 발생 원인이라는 관점에서 의미 있게 다루어지고 있다. 최근 저열량탄이 증가함에 따라 시멘트의 원료로 재활용되던 석탄회에서 다량의 미연분과 tar-soot가 포함되어 오히려 다시 반입되는 사례가 빈번해지고 있다. 따라서 본 연구에서는 저열량탄 사용 확대에 따른 혼탄연소 조건에서 tar-soot의 배출특성을 살펴보기 위해 반응기로써 LFR(Laminar Flow Reactor)을 적용하였으며, 연료로는 현재 국내발전소에서 사용 중인 역청탄 2종(MOUNTAIN, MACARHTUR)과 아역청탄(KPU)을 이용하여 단탄별 tar-soot 배출특성과 혼소비에 따른 배출특성을 화염의 구조 변화와 함께 측정하였다. 휘발분이 많은 아역청탄의 soot cloud 길이는 역청탄에 비해 길었지만 전체적인 화염 길이는 짧아졌다. 단탄별 실험결과에서는 역청탄의 tar-soot 발생량이 아역청탄의 발생률보다 높았으며 역청탄 중 휘발분 함량이 많은 MOUNTAIN탄이 상대적으로 휘발분 함량이 적은 MACARHTUR탄의 tar-soot 발생률보다 높았다. 혼소시에는 단탄의 연소특성과는 다른 새로운 특성을 나타내었으며 저열량탄과 혼소되는 역 청탄의 종에 따라 tar-soot 발생량이 지배되는 것을 확인하였으나 혼소비에 따른 평균적 특성이 아닌 완전히 차별되는 배출특성을 나타냄에 따라 석탄의 등급에 따라 최적의 혼소비를 찾아서 연소시키는 것이 tar-soot 발생량을 줄일 수 있는 방법임을 의미한다.