• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.5
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• pp.355-364
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• 2009

Electro-Luminescence (EL) sheets have been widely used in lighting displays, mainly used as advertisement panels. To drive the ELs in optimal conditions, it is required to understand the load profile of the EL. Hence, in this paper, a modeling for an EL sheet was performed to analyze the load characteristics of the EL. Based on the extracted model of the EL, a topology for inverter system was chosen and the optimal design parameters were obtained. The validity of the designed EL driver system was verified through computer simulations and experiments.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.11
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• pp.922-927
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• 2001

Single-layer green ELs was fabricated with using molecularly-dispersed Bu-PBD into poly-N-vinylcarbazole(PVK) which has low operating voltage and high quantum efficiency. A EL cell structure of glass substrate/indium-tin-oxide/PVK:Bu-PBD:C6(∼ 100nm)/Ca(20nm)/Al(20nm) was employed with variable doping concentration. The keys to obtain high quantum efficiency was excellent film forming capability of molecularly dispersed into PVK and appropriate combination of cathode for avoiding exciplex. We obtained the turn-on voltage of 4.2V and quantum efficiency of 0.52% at 0.lmol% of C6 concentration which has been improved about a factor of 50 in comparison with the undoped cell. The PL peak wavelengths wouldn\`t be turned by changing the concentration of the C6 dopant. Green EL emission peak and FWHM were 520nm and 70nm respectively. PL emission peak was obtained at 495nm.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.876-878
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• 2019

본 연구에서는 금융 분야에서 AI 기술을 이용하여 챗봇 기반의 예측 시스템을 구축하는데 목적이 있다. 사용자가 이해하기 쉽게 챗봇 기반으로 실시간 서비스를 제공하며 투자 경험이 없는 사용자를 타겟으로 투자 추천을 하는 것을 목표로 개발하였다. 챗봇 기반의 금융 어플리케이션에서는 종목 주가조회, 코스피 상위 조회, 예측결과 조회, ELS상품추천 등으로 크게 네 가지의 의도파악을 하며 자연어 처리와 단어 매칭 처리를 통해서 사용자에게 최적화된 정보를 제공한다. 정보의 질을 높이기 위해서 인공지능 학습은 10년 치의 데이터를 학습시켰으며 비슷한 패턴을 예측해서 제공한다. 상장기업의 주식과 은행에서 판매하는 ELS를 추천하고 있으며, 챗봇 서비스를 통해 사용자와 실시간적으로 소통할 수 있는 AI기반의 금융 시스템을 제공한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.04a
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• pp.928-933
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• 2000

정보 사회에서 교육 패러다임의 급격한 변화는 학교, 교사, 학생의 역할 변화를 포함하고 있다. 수업의 방향이 교사주도에서 학습자 주도로 바뀌어감에 따라 학생들은 자기 주도적 학습을 수행하는 동안에 다양한 지원을 필요로 한다. EPSS(Electronic Performance Support System)는 기업체, 기관, 학교 등에서 업무 수행자가 원하는 순간에 지원을 의뢰할 수 있는 수행 지원 시스템으로, 본 논문에서는 이러한 EPSS를 프로토타입으로 설정하여, 학습 패러다임의 변화를 지원해 줄 수 있는 ELSS(Electronic Learning Support System)에 관한 모델 개발을 시도하고 학습 적용 가능성을 타진하였다. 먼저, EPSS에 관한 다양한 이론들을 고찰해 보았고 이를 토대로 ELSS의 개념, 설계시 고려사항, 구성요소 등으로 구성된 ELSS 모델을 제안하였다.

• Bulletin of the Korean Chemical Society
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• v.20 no.5
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• pp.559-566
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• 1999

Gas-phase alkylations of delocalized ambident anions, Y---CH---X- where X, Y=CH2, O, or S, have been investigated theoretically at the MP2/6-31+G*//MP2/6-31+G* and QCISD/6-31+G*//MP2/6-31+G* lev-els. O-and S-alkylations (X=O and S) are more favored kinetically by ΔE^≠ = 4.6 and 9.8 kcal mol-1 than the respective C-alkylations even though they are thermodynamically less favored by 22.4 and 6.0 kcal mol-1 respectively. It was found that the transition structures for the C-alkylations are imbalanced due to the endoergic rehybridi-zation of the carbon center from sp2 to sp3 which leads to premature bond contraction of the C-Y bond and delayed bond stretching of the C-X bond. In the O-, or S-alkylation, such endoergic process is not required since the σ-lone pair on O or S is involved in the initial stage of alkylation. The imbalanced TSs for the C-alkylation are accompanied by higher intrinsic barriers and deformation energies.

• Journal of Life Science
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• v.29 no.9
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• pp.1002-1009
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• 2019

Early life stress (ELS) increases the risk of depression. ELS may be involved in the susceptibility to subsequent stress exposure during adulthood. We investigated whether epigenetic mechanisms of p11 promoter affect the vulnerability to chronic unpredictable stress (CUS) induced by the maternal separation (MS). Mice pups were separated from their dams (3 hr/day from P1-P21). When the pups reached adulthood, we applied CUS (daily for 3 weeks). The levels of hippocampal p11 expression were analyzed by quantitative real-time PCR. The levels of acetylated and methylated histone H3 at p11 promoter were measured by chromatin immunoprecipitation. Depression-like behavior was measured by the forced swimming test (FST). The MS and CUS group exhibited significant decreases in p11 mRNA level and the MS plus CUS group had a greater reduction in this level than the CUS group. The MS plus CUS group also resulted in greater reduction in H3 acetylation than the CUS group. This reduction was associated with an upregulation of histone deacetylase 5. Additionally, the MS plus CUS group showed a greater decrease in H3K4met3 level and a greater increase in H3K27 met3 level than the CUS group. Consistent with the reduction of p11 expression, the MS plus CUS group displayed longer immobility times in the FST compared to the control group. Mice exposed to MS followed by CUS had much greater epigenetic alterations in the hippocampus compared to adult mice that only experienced CUS. ELS can exacerbate the effect of stress exposure during adulthood through histone modification of p11 gene.

• Journal of Chest Surgery
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• v.31 no.12
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• pp.1206-1211
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• 1998

Background: Pulmonary sequestration is not common and it's diagnosis needs special care such as an aortogram ar tomography. Material and Method: We have experienced 13 patients who had pulmonary sequestration from January 1990 to September 1997. Result: Six men and seven women were treated and their mean age was 25.8±14.3 years. Their chief complaints were coughing, chest pain, and no symptoms in decreasing order. There were nine intralobar(ILS) and three extralobar(ELS) pulmonary sequestrations and one patient had both. There was no preference in location of either left or right. They were mainly diagnosed by aortography and their feeding arteries commonly originated from the lower thoracic aorta. The patients with ILS were treated by lobectomy and those with ELS by sequestrectomy. Conclusion: to treat pulmonary sequestration properhy, aortogram or chest CT is warranted to iidenty the abnormal origin of feeding artery.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.311-319
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• 2019

The purpose of this study was to evaluate the effects of a computerized cognitive training(CCT) on cognitive, depression, life satisfaction and activity of daily living in older adults with mild dementia. The participants were 32 older adults diagnosed with mild dementia who reside in nursing hospital and were randomly divided into an 16 for an experimental group and 16 for a control group. A CCT was performed for a day/week for 8 weeks in an experimental group. The CoTras-G was used for CCT. The MMSE-K, SGDS-K, ELS and BI were administered to the experimental group and the control group in the same way in order to examine the effects of CCT. The difference of the effects between before and after a CCT conduction were identified by paired t-test. Moreover, the Mann-Whitney U-test was conducted to identify differences in variances between groups. Only participants in the experimental group reported significant improvements in cognitive function, depression, life satisfaction and activity of daily living when compared to those in the control group after CCT. There was a significant difference in cognitive function, depression, life satisfaction and activity of daily living between the experimental group and the control group after CCT. These findings suggest that the CCT can be used as effective cognitive training program to improve cognitive function, depression, life satisfaction and activity of daily living in older adults with mild dementia.

• Korean Journal of Plant Tissue Culture
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• v.27 no.4
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• pp.245-258
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• 2000

Somatic embryogenesis has become a major tool in the study of plant embryology, as it is possible in culture to manipulate cells of many plant species to produce somatic embryos in a process that is remarkably similar to zygotic embryogenesis. Traditionally, the process has been studied by an examination of the ex vitro factors which influence embryo formation. Later structural, physiological and biochemical approaches have been applied. Host recently, molecular tools are being used. Together, these various approaches are giving valuable information on the process. This article gives an overview of somatic embryogenesis by reviewing information on the morphogenesis, physiology, biochemistry and molecular biology of the process. Topics covered include a brief description of the factors involved in the production of embryogenic cells. Carrot cell suspension is most commonly used, and the development of a high frequency and synchronous system is outlined. At the physiological and biochemical lev-els various topics, including the reactivation of the cell cycle, changes in endogenous growth regulators, amino acid, polyamine, DNA, RNA and protein metabolism, and embryogenic factors in conditioned medium are all discussed. Lastly, recent information on genes and molecular markers of the embryogenic process are outlined. Somatic embryogenesis, the best example of totipotency in plant cells, is not only an important tool in studies in basic biology, but is potentially of equal significance in the micropropagation of economically important plants.

• Magazine of the Korea Concrete Institute
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• v.2 no.1
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• pp.101-108
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• 1990

An experimental and analytical invest.igation was conducted regarding the behavior of reinforced concrete skew bridge decb with Ontario-type reinforcement. A full-scale model repmsenting the essential behavior of a full skew bridge was built and tested. The test specimen had details similar to those required by the Ontario Highway Bridge Design Code, modified as recommended by the Texas State Highway Dopartment. The skuw bridge deck performed sati:,factorily under the current AASHTO design load le"els as well as the overload conditions(about :3 times the current AASHTO design wheel load). The skew edges failed by shear ; the center by punching shear. The calculated flexural capacity considering arching action always far exceeded the actual failure load (shear or punching shear) at each test location. To check the experimental results a detailed finite element model of the specimen was developed using a general-purpose structural analysis pmgram. Analytical predictions and exper'imental results agreed c1osuly.