• 대한치과기공학회지
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• 제31권4호
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• pp.25-30
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• 2009

Zirconia($ZrO_2$) has attracted much attention in science and technology because of its high refractive index, high melting temperature, hardness, low thermal conductivity and corrosion barrier properties. And it is widely used as the dental restoration material because of its esthetic appearance. In this research, we analyzed the particle size and composition of the imported dental porcelain for zirconia. And the glass frit was produced. To decrease the glass transition temperature and softening temperature of the glass frit, $Li_2O$ was added into it and the effect of $Li_2O$ on the firing temperature was researched. Then the glass which contains leucite crystal with a high coefficient of thermal expansion(CTE) was manufactured and it was mixed with the glass frit to control the CTE. The phase composition were analyzed using the X-ray diffraction. The morphologies of the samples were observed by the scanning electron microscope. The 4wt% $Li_2O$-added glass frit has the optimal glass transition temperature and softening temperature. And 6 wt% leucite crystal was mixed with the glass frit to control the CTE. From the experimental results of crystallization, the crystal phase was found only leucite crystal.

• Journal of the Optical Society of Korea
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• 제7권3호
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• pp.188-192
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• 2003

The modal characteristics of the photonic crystal fibers are analyzed using the reliable and efficient plane wave expansion method. The mode profile, effective index and group velocity dispersion are obtained by solving Maxwell's vector wave equations without any approximation. The zero dispersion condition of a photonic crystal fiber is derived over a wide range of wavelengths. Higher-order modes are also easily found as a by-product of the plane wave expansion method. This method can be used to quickly and accurately design various optical properties of photonic crystal fibers.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권6호
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• pp.2619-2643
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• 2018

In this paper, a new clustering algorithm based on the connected region generation (CRG-clustering) is proposed. It is an effective and robust approach to clustering on the basis of the connectivity of the points and their neighbors. In the new algorithm, a connected region generating (CRG) algorithm is developed to obtain the connected regions and an isolated point set. Each connected region corresponds to a homogeneous cluster and this ensures the separability of an arbitrary data set theoretically. Then, a region expansion strategy and a consensus criterion are used to deal with the points in the isolated point set. Experimental results on the synthetic datasets and the real world datasets show that the proposed algorithm has high performance and is insensitive to noise.

• 대한건축학회논문집:구조계
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• 제34권3호
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• pp.3-10
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• 2018

It's not practical to collect all information at the entire degrees of freedom of finite element model. The incomplete measurements should be expanded for subsequent analysis and damage detection. This work presents the analytical methods to expand the incomplete static or dynamic response data. Using the expanded data, introducing the concept of residual force, and minimizing the performance index expressed as the stiffness matrix and its difference before and after damage, the variation in stiffness matrix is derived. Based on the difference in the stiffness matrix, the damage detection method of structures is also provided. The validity of the proposed methods is illustrated in a numerical application, the numerical results are analyzed for applications, and the applicability of both methods is investigated.

• 한국식생활문화학회지
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• 제25권6호
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• pp.755-763
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• 2010

The purpose of this study was to select market variables that a foodservice company should consider when expanding overseas and to regional market analysis by variables. Twenty-three different variables were derived from 17 previous studies. These were: population, urbanization rate, women employed, enrollment in tertiary education, gross domestic product, value added by service, total number of mobile cellular telephone subscribers, number of internet users, total Asian highway, inward foreign direct investment, total service imports, inflation rate, international tourist arrivals, energy use by industry, growth rates of the food consumer price index, access to urban sanitation, per capita total expenditure on health, male life expectancy at birth, adult literacy rate, contributing women family workers, passenger car, and country risk assessment. The selected variables were collected as secondary data from the UN, Asian Development Bank, International Bank for Reconstruction and Development, and Michigan State University.

• 전기학회논문지
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• 제59권1호
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• pp.26-32
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• 2010

This paper proposes a new effective installed reserve rate in order to evaluate reliability of power system considering renewable generators, which include uncertainty of resource supply. It is called EIRR(effective installed reserve rate) in this paper. It is developed with considering capacity credit based on ELCC by using LOLE reliability criterion. While the conventional installed reserve rate index yields over-evaluation reliability of renewable generators, the proposed EIRR describes actual effective installed reserve rate. However, it is not the probabilistic reliability index as like as LOLE or EENS but another deterministic effective reliability index. The proposed EIRR is able to evaluate the realistic contribution to the reliability level for power system considering wind turbine generators and solar cell generators with high uncertainty in resource supply. The case study in model system as like as Jeju power system size presents a possibility that the proposed EIRR can be used practically as a new deterministic reliability index for generation expansion planning or operational planning in future.

• 산경연구논집
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• 제8권6호
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• pp.33-40
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• 2017

Purpose - This study attempted to discover the impact of the Korea-China FTA(Free Trade Agreement) on electronic products distribution industry. Strategies will be provided to expand both countries' trade after the Korea-China FTA. Research design, data, and methodology - This study analyzed the differences before and after the Korea-China FTA, using an RCA(Revealed Comparative Advantage) index, TC(Technology Sophistication Index) index and TSI(Trade Specialization Index) that considered the FTA tariff situation. Data was collected from the International Trade Statistics Database and Korea, China Customs Service. Results - The results indicate that following the Korea-China FTA, China and Korea's bilateral trade of electronic products is expected to expand, and both countries will experience net welfare gains from the markets' expansion. Korea is competitive in several key products, although it faces competition from China. China's electronic products' competitiveness have indicated an increasing trend. Conclusions - The two countries should closely cooperate and communicate with each other. Ultimately, Korea should focus on high-tech, sophisticated techniques to gain market advantage. On the other hand, with the tariff decrease as well as the labor cost and labor force base, China will greatly be able to benefit from the manufacturing of medium- to low-end products in the future.

• Journal of Chest Surgery
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• 제7권1호
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• pp.1-8
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• 1974

Acute pulmonary edema was induced by intravenous injection of epinephrine, intravenous infusion of dextran and intratracheal instillation of acid solution index was determined from pressure volume curves in excised lungs. Surface activity was also investigated with measurements of maximum and minimum surface tension and stability index on saline extracts of same lungs. The results were as follows. 1. The expansion index of excised lung in which pulmonary edema was induced by intravenous injection of epinephrine, intravenous infusion of dextran and intratracheal instillation of acid solution was ignificantly decreased as compared with the normal control of $0.86{\pm}0.017$ to $0.74{\pm}0.03$, $0.71{\pm}0.081$and $0.76{\pm}0.02$, respectively. 2. The deflation curves of excised lungs in which pulmonary edema was induced were significantly decreased as compared with the normal controls. 3. The minimum surface tension of excised lung in which pulmonary edema was induced was significantly increased in each groups and stability index was significantly decreased as compared with the normal controls 0.78 to $0.35{\pm}0.039$, $0.29{\pm}0.02 $ and $0.31{\pm}0.083$, respectively. 4. The decrease of pulmonary surface activity in acute pulmonary edema was in proportion to the degree of pulmonary edema regardless of their etiology.

• Journal of the Korean Data and Information Science Society
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• 제20권6호
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• pp.1049-1060
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• 2009

국내 금융시장의 변동성의 확대는 개인투자자들의 직접투자를 어렵게 만들면서 펀드를 통한 간접 투자 비중을 증가시켰다. 본 연구의 목적은 여러 가지 형태의 펀드 중에서도 인덱스펀드를 바탕으로 초과수익을 추구하는 인핸스드 인덱스 펀드 모델을 구축하는데 있다. 유전자알고리즘을 활용하여 인덱스펀드 관리를 위한 포트폴리오 최적화 모델을 제안하고, 이렇게 얻은 인덱스펀드의 수익에 초과수익을 얻을 수 있도록 기준지수의 일별 거래대금과 종가를 활용하였다. 실증분석 결과 본 연구의 제안모델은 코스피 200의 움직임을 잘 반영하고 있으며, 이를 활용한 전략은 순수 인덱스펀드에 의한 단순매수 후 보유 전략보다 적절한 개수의 종목을 편입시킨다면 높은 수익률을 가져다줌을 알 수 있었다.

• 디지털융복합연구
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• 제14권11호
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• pp.135-142
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• 2016

최근 중동의 주요 국가들의 경제 성장과 맞물려 우리나라와의 다양한 분야에서의 경제협력 및 교류의 가능성에도 불구하고 그동안 이 지역과 경제협력과 관련된 연구와 자료가 부족했으며 특히, 이 지역과의 교역구조 및 동향과 관련된 논문은 거의 찾아 볼 수 없었다. 이에 본 연구는 우리나라와 주요 GCC(Gulf Cooperation Council) 국가(사우디아라비아, 아랍에미레이트, 카타르) 간에 최근 5년 동안 무역결합도 지수 분석과, 무역보완도, 국별편향도 지수 분석을 통해 향후 GCC 국가로의 한국의 수출 및 교류의 확대의 가능성을 살펴보고, 더 나아가 FTA 체결에 대한 시사점을 검토해 보는 것을 목적으로 하였다. 분석결과 중동의 주요 3개 국가 모두 산업구조상 한국과 상호보완 관계가 이루어져 있어 국가 간 자본이동을 점증적으로 증가시키거나 무역장벽을 낮추도록 노력한다면 향후 무역보완도와 국별편향도를 더욱 증가 시킬 수 있을 것으로 나타났다. 특히 한국과 사우디 간의 무역 및 교역 구조는 3국 중에서 가장 상호 보완관계가 높아 미래 FTA의 체결을 통해 우리나라의 수출증대와 더불어 양국 간 교역을 활성화 할 수 있는 새로운 기회를 창출할 수 있을 것으로 기대된다.