• 대기
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• 제18권1호
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• pp.55-70
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• 2008

The global time slice approach is a transient experiment using high resolution atmosphere-only model with boundary condition from the low resolution globally coupled ocean-atmosphere model. The present study employs this "time slice concept" using ECHAM4 atmosphere-only model at a horizontal resolution of T106 with the lower boundary forcing obtained from a lower-resolution (T42) greenhouse gas + aerosol forcing experiment performed using the ECHO-G/S (ECHAM4/HOPE-G) coupled model. In order to assess the impact of horizontal resolution on simulated East Asian summer monsoon climate, the differences in climate response between the time slice experiments of the present and that of IPCC SRES AR4 participating 21 models including coarser (T30) coupled model are compared. The higher resolution model from time slice experiment in the present climate show successful performance in simulating the northward migration and the location of the maximum rainfall during the rainy season over East Asia, although its rainfall amount was somewhat weak compared to the observation. Based on the present climate simulation, the possible change of East Asian summer monsoon rainfall in the future climate by the IPCC SRES A1B scenario, tends to be increased especially over the eastern part of Japan during July and September. The increase of the precipitation over this region seems to be related with the weakening of northwestern part of North Pacific High and the formation of anticyclonic flow over the south of Yangtze River in the future climate.

• Nuclear Medicine and Molecular Imaging
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• 제43권3호
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• pp.159-164
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• 2009

Coronary artery disease is on the rise over the world. Myocardial perfusion SPECT is a well established technique to detect coronary artery disease and to assess left ventricular function. In addition, it has the unique ability to predict the prognosis of the patients. Moreover, the application of ECC-gated images provided the quantitatve data and improved the accuracy. This approach has been proved to be cost-effective and suitable for the emerging economies as well as developed countries. However, the utilization of nuclear cardiology procedures vary widely considering the different countries and region of the world. Korea exits 2-3 times less utilization than Japan, and 20 times than the United States. Recently, with the emerging of new technology, namely cardiac CT, cardiac MR and stress echocardiography, the clinical usefulness of nuclear cardiology has been called in question and its role has been redefined. For the proper promotion of nuclear cardiology, special educations should be conducted since the nuclear cardiology has the contact points between nuclear medicine and cardiology. Several innovations are in horizon which will impact the diagnostic accuracy as well as imaging time and cost savings. Development of new tracers, gamma camera technology and hybrid systems will open the new avenue in cardiac imaging. The future of nuclear cardiology based on molecular imaging is very exciting. The newly defined biologic targets involving atherosclerosis and vascular vulnerability will allow the answers for the key clinical questions. Hybrid techniques including SPECT/CT indicate the direction in which clinical nuclear cardiology may be headed in the immediate future. To what extent nuclear cardiology will be passively absorbed by other modalities, or will actively incorporate other modalities, is up to the present and next generation of nuclear cardiologists.

• 한국인터넷방송통신학회논문지
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• 제18권2호
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• pp.117-123
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• 2018

본 연구에서는 이미지 기울기 영역에서 포아송 방정식을 이용한 빠른 이미지 재구성 기법을 제안한다. 포아송 방정식을 사용하는 이 접근법에서, 유도된 벡터 필드는 제 1 단계에서 선택된 영역 내에서 원본과 대상 이미지를 사용함으로써 생성된다. 다음으로, 유도된 벡터는 결과 이미지를 생성하는데 사용된다. 우리는 원하는 기울기 집합과 데이터 항을 근사화하는 2차원 함수를 재구성하는 문제를 분석했다. 결합된 데이터와 기울기는 원본 이미지에 가깝게 머무르는 동안 이미지 기울기를 수정하는 것처럼 작동 할 수 있다. 이 공식으로부터 우리는 물리학에서 알려진 포아송 방정식을 찾아냈다. 이 방정식은 FFT 도메인의 문제에 대한 효율적인 해결책을 제시한다. 이것은 2차원으로 알려진 포아송 모델을 해결하고 기울기 비례축소는 라플라스를 확실하게 일반화하는 잘 정의된 선명한 필터임을 공간 필터에 잘 나타냅니다. 포아송 모델을 기반으로 이산 코사인 변환을 사용하여 결과를 확인할 수 있었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.2122-2136
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• 2010

도시철도 수요는 일반적으로 4단계 모형에 의해서 역별로 추정하는 경우에는 기존의 모형식으로는 한계를 가지고 있다. 기존의 모형은 행정동 기반으로 도시철도의 수요가 추정되기 때문에 도시철도의 공간적인 역세권의 특성을 반영하기 어렵다. 본 연구에서는 서울시 및 수도권의 역사를 대상으로 설문조사를 통하여 역세권의 공간적 범위별 수단선택의 행태를 분석하고, 모형개발을 위한 기초조사를 목적으로 한다. 본 연구에서는 국내 및 국외의 역세권 설정을 검토하고, 사례조사를 통한 역세권의 공간적 범위 연구, 공간적 범위에 따른 수단 선택 분석, 역세권의 사회, 경제지표의 자료를 토대로 역별 수요를 추정하는 방안이다. 이방안은 자료 수집과 분석에 많은 시간과 노력이 소요되므로 본 연구에서 설문조사한 역사를 대상으로 실적치와 모형치를 검증하는 것으로 한다. 본 연구의 추정결과 역세권을 500m,1000m로 구분하여 추정할 경우 역별 수요의 실적치와 모형치가 가장 근사한 결과를 나타내었다.

• 한방안이비인후피부과학회지
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• 제29권4호
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• pp.114-130
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• 2016

Objectives : This study is performed to investigate the therapy on tinnitus through the literature of Eastern and Western medicine. Methods : This study review the definition, etiology, classification, internal and external methods of treatment of tinnitus based on 50 articles of Eastern medicine, 16 articles of Western medicine about the treatment of tinnitus. Results : The results were as follows. 1. In Eastern medicine, the cause and mechanism of disease of tinnitus arose from the state of qi-blood deficiency, internal dampness-heat and depression stagnation. In Western medicine, there are mainly caused by damage to the auditory system the lower induced changes in the upper. 2. In Eastern medicine, differentiation of syndromes classifies clinical aspects, and cause and mechanism of disease. In Western medicine, it divides into an generating region, clinical and associated symptoms aspects. 3. In Eastern medicine, internal method of treatments of tinnitus are divided into four treatments. In Western medicine, internal methods of tinnitus are vasodilators, blood-flow improvers, Metabolism improvers etc. 4. In Eastern medicine, external method of treatments of tinnitus are paste preparation method, powder preparation method, pill preparation method, acupuncture & moxibustion method. In Western medicine, external method of treatments of Tinnitus are divided into injection, other surgical therapies and adjuvant therapy. Conclusions : Until now, there is no perfect, effective single treatment. We think that Eastern medicine approach and treatment can be helpful to overcome the limitations of tinnitus cure.

• 천문학회지
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• 제52권6호
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• pp.217-225
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• 2019

We apply a modified Convolutional Neural Network (CNN) model in conjunction with transfer learning to predict whether an active region (AR) would produce a ≥C-class or ≥M-class flare within the next 24 hours. We collect line-of-sight magnetogram samples of ARs provided by the SHARP from May 2010 to September 2018, which is a new data product from the HMI onboard the SDO. Based on these AR samples, we adopt the approach of shuffle-and-split cross-validation (CV) to build a database that includes 10 separate data sets. Each of the 10 data sets is segregated by NOAA AR number into a training and a testing data set. After training, validating, and testing our model, we compare the results with previous studies using predictive performance metrics, with a focus on the true skill statistic (TSS). The main results from this study are summarized as follows. First, to the best of our knowledge, this is the first time that the CNN model with transfer learning is used in solar physics to make binary class predictions for both ≥C-class and ≥M-class flares, without manually engineered features extracted from the observational data. Second, our model achieves relatively high scores of TSS = 0.640±0.075 and TSS = 0.526±0.052 for ≥M-class prediction and ≥C-class prediction, respectively, which is comparable to that of previous models. Third, our model also obtains quite good scores in five other metrics for both ≥C-class and ≥M-class flare prediction. Our results demonstrate that our modified CNN model with transfer learning is an effective method for flare forecasting with reasonable prediction performance.

• 콘크리트학회지
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• 제6권3호
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• pp.201-214
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• 1994

본 연구는 콘크리트용 혼화재로서 우리나라에 풍부한 천연 실리카 질 광물을 이용하여 콘크리트의 강도증진 가능성 및 유용성과 경제적인 효율성에 대해 검토한 것이다. 제반 실험을 통해 얻어진 결론을 요약하면 다음과 같다. \circled1 최적의 제오라이트 치환율은 단위 시멘트당 5~10% 정도를 나타났으며, 그 때의 강도 증진율은 무첨가 콘크리트 값에 비해 대체적으로 40%정도의 강도증진 효과를 얻었다. \circled2 최적의 이암 치환율은 단위 시멘트량당 10~15% 정도로 나타났으며, 그때의 강도 증진율은 무첨가 콘크리트 값에 비해 대체적으로 10%정도의 강도증진 효과를 얻었다. 이러한 검토로부터 우리는 혼화재로서 콘크리트의 강도성능의 향상을 목적으로 기존의 실리카 흄, 플라이 애쉬 등의 대체품으로 천연 실리카 광물을 활용할 수 있다는 결론을 얻었다.

• 한국콘텐츠학회논문지
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• 제10권3호
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• pp.364-372
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• 2010

본 연구의 목적은 자연휴양림의 방문한 이용객들의 방문동기를 통한 군집분석을 통하여 이용객을 분류하고 그에 따른 행동의도간의 차이를 검증하여 그에 따른 세분화된 이용객들의 차별화된 마케팅 및 경영전략을 수립하는데 그 목적이 있다고 할 수 있다. 이의 측정을 위하여 1년 이내에 자연휴양림을 이용한 적이 있는 방문객들을 대상으로 자연휴양림 방문동기에 대한 요인 분석을 실시한 후 군집분석을 실시하여 군집을 분류하였으며, 분류된 군집을 인구통계학적 특성과의 교차분석을 실시하여 군집의 유형화를 실시하였다. 유형화된 군집을 통하여 만족도, 재방문 및 추천의도에 대한 차이검정을 실시하였다. 분석결과 방문동기에 대한 요인분석 결과 3개의 요인으로 분류되었으며, 이를 통해 계층적 군집분석과 K-means군집분석을 통하여 2개의 군집을 도출하였으며, 2개의 군집을 다시 교차분석을 통하여 군집의 유형화를 실시하여 미혼의 100만원 미만의 군집과 기혼의 200~300만원의 군집 집단으로 유형화를 실시하였다. 이 군집을 자연휴양림 방문 후 행동의도간의 차이분석을 실시하였으며, 그 결과 전반적으로 만족, 즐거운 시간을 보냄, 방문은 현명한 선택, 재방문의도, 추천의도 모두 유의한 차이가 있는 것으로 나타났다. 군집 2인 기혼의 200~300만원의 집단에 더 높은 행동의도를 보이고 있는 것으로 나타나 차별화된 마케팅 전략이 필요시 되며, 또한 자연휴양림 공익적 성격을 고려하여 각 집단에 대하여 모두 소구할 수 있는 서설 및 서비스의 개발이 요구 된다.

• 한국응용과학기술학회지
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• 제30권1호
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• pp.49-56
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• 2013

Excellent electron transport properties with enhanced light scattering ability for light harvesting have made well-ordered one dimensional $TiO_2$ nanotube(TNT) arrays an alternative candidate over $TiO_2$ nanoparticles in the area of solar energy conversion applications. The principal drawback of TNT arrays being activated only by UV light has been addressed by coupling the TNT with secondary materials which are visible light-triggered. As well as extending the absorption region of sunlight, the introduction of these foreign components is also found to influence the charge separation and electron lifetime of TNT. In this study, a novel method to fabricate the TNT-based composite photoelectrodes employing visible responsive $CuInS_2$ (CIS) nanoparticles is presented. The developed method is a square wave pulse-assisted electrochemical deposition approach to wrap the inner and outer walls of a TNT array with CIS nanoparticles. Instead of coating as a dense compact layer of CIS by a conventional non-pulsed-electrochemical deposition method, the nanoparticles pack relatively loosely to form a rough surface which increases the surface area of the composite and results in a higher degree of light scattering within the tubular channels and hence a greater chance of absorption. The excellence coverage of CIS on the tubular $TiO_2$ allows the construction of an effective heterojunction that exhibits enhanced photoelectrochemical performance.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.18-18
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• 2010

Methods of the characteristics evaluation of turbo-molecular pumps (TMP) are well-defined in the international measurement standards such as ISO, PNEUROP, DIN, JIS, and AVS. The Vacuum Center in the Korea Research Institute of Standards and Science has recently designed, constructed, and established the integrated characteristics evaluation system of TMPs based on the international documents by continuously pursuing and acquiring the reliable international credibility through measurement perfection. The measurement of TMP pumping speed is normally performed with the throughput and orifice methods dependent on the mass flow regions. However, in the UHV range of the molecular flow region, the high uncertainties of the gauges, mass flow rates, and conductance are too critical to precisely accumulate reliable data. With UHV gauges of uncertainties less than 15% and a calculated conductance of the orifice, about 35% of pumping speed uncertainties are experimentally derived in the pressure range of less than $10^{-6}$ mbar. In order to solve the uncertainty problems of pumping speeds in the UHV range, we introduced an SRG with 1% accuracy and a constant volume flow meter (CVFM) to measure the finite mass flow rates down to $10^{-3}$ mbar-L/s with 3% uncertainty for the throughput method. In this way we have performed the measurement of pumping speed down to less than $10^{-6}$ mbar with an uncertainty of 6% for a 1000 L/s TMP. In this article we suggest that the CVFM has an ability to measure the conductance of the orifice experimentally with flowing the known mass through the orifice chambers, so that we may overcome the discontinuity problem encountering during introducing two measurement methods in one pumping speed evaluation sequence.