• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.825-828
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• 2006

The most commonly used techniques for image magnification are interpolation based. However, the magnified images produced by this technique often appear blocking and blurring phenomenon when the image is enlarged. In this paper, we enhanced image magnification algorithm using edge information. The proposed algorithm not used interpolation based but by using sub-band of input image in extrapolation. According to mapping relationship in pyramid, we calculated up-band information to magnify. In experiments, the proposed model shows solved the problem of image loss like the blocking and blurring phenomenon. As the result, it is faster and higher resolution than traditional magnification algorithms.

• Microbiology and Biotechnology Letters
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• v.43 no.3
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• pp.177-186
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• 2015

With a view to supporting the provisions of the current Korean food code for the detection of Benzo[a]pyrene, various analytical methods of detection in foods were evaluated and established in terms of linearity, limits of detection/quantitation, efficiency, and accuracy, amongst others. It was observed that to improve the technologies involved in the application of these methods, complicated and combined preparation processes of foods, including extraction, separation and purification, have been the main focus of efforts at optimization. Recently, on-site quick reaction for the detection of hazardous substances in the environment and food materials aims at developing simplified examination processes, such as lable-free and non-invasive technological analysis, to reduce the costs and time involved in the examination. Herein, current benzo[a]pyrene detection methods are reviewed in addition to new Raman spectroscopy-based trials established to pursue improve the speed, simplicity and suitability of testing.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.1
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• pp.1-10
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• 2011

Recently harbor remodeling projects are seriously considered to enhance the loading and unloading capability of old container terminals and to make decrepit ports as eco-friendly harbor and waterfront spaces in many countries. In such a case, quantitative and qualitative evaluations on concrete harbor facilities are mandatory to determine the current structural integrity condition of aged materials. Once the remodeling project is determined to be carried out, the reusability of individual structural members and facilities including caissons, cell-blocks, and tetra-pods need to be decided based on the simple and economic visual inspection and/or nondestructive testing. In this study, the systematic quantitative evaluation procedure for determining the structural integrity condition and the reusability is studied based the nondestructive testing and evaluation methods. Conventional methods including Schmidt hammer test and ultrasonicpulse velocity methods and elastic wave based methods including impact echo test and surface wave test are applied to the old harbor facilities in five different sites. The compressive tests are also carried out to determine the elastic modulus and compressive strength of concrete materials.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.39-40
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• 2008

본 논문은 네트워크 기반 제어시스템(NCS: Networked Control Systems)모델매칭 제어기법을 적용한 효율적인 제어알고리즘을 제안한다. 비선형의 특징을 가지는 제어기 및 관측기의 시간지연을 Pade 근사법으로 선형화하여 선형시스템 이론을 적용한 모델매칭 제어기를 설계하였다. 또한, 제어기의 차수를 줄이기 위하여 저차시스템으로 근사화하여 그 타당성을 검증하였다. 제안한 제어알고리즘의 타당성 및 신뢰성을 검증하기 위하여 컴퓨터 시뮬레이션을 실시하였으며 기존의 PID 제어기법과 비교분석하였다.

• ETRI Journal
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• v.11 no.3
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• pp.11-22
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• 1989

Stress에 잘 견딜 수 있는 metal-oxide-semiconductor field effect transistor(MOSFET)의 매우 얇고(10mm 이하) 고신뢰성을 갖는 게이트 절연막을 개발하기 위해서 급속열처리법을 이용하여 제조한 재산화질화산화막의 특성에 관하여 연구하였다. AES 분석에 의하여 8nm 두께의 초기산화막을 질화시킬 때 산화막의 계면이 우선적으로 질화가 일어났으며, 질화된 막을 재산화시킬 때 표면과 계면의 [N]가 감소하였다. 또한 재산화시킬 경우 두께가 약간 증가함을 보였으며, 질화가 강하게 될수록 두께 증가는 크지 않았다. 전기적 특성으로써 I-V 특성과 고주파(1MHz) C-V 특성, 정전류 stress 후의 고주파 C-V 특성 변화 들을 조사한 결과 $950^{\circ}C$ 60초 동안 질화시킨 재산화질화산화막($ONO_L막$) 은 정전류 stress에 대하여 flat band 전압 변화에 계면 상태 밀도(interface state density)변화가 적고, 절연파괴전압(breakdown voltage)특성 등이 우수하게 나타났다.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.164-164
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• 2015

최근에 고효율의 적색 발광체를 개발하고자 무기물 모체에 다양한 활성제 이온을 주입하는 연구가 상당한 관심을 끌고 있다. 본 연구에서는 발광 효율이 높은 적색 형광체 분말을 제조하고자 두 종류의 활성제 이온 $Eu^{3+}$와 $Sm^{3+}$가 도핑된 $Y_2MoO_6$형광체 분말을 고체상태 반응법을 사용하여 전기로에서 $400^{\circ}C$에서 하소와 $1100^{\circ}C$에서 소결공정을 통하여 제조하였다. 활성제 이온의 몰 비에 따른 적색 형광체의 결정 구조, 발광과 흡광 스펙트럼을 조사하였다. 파장 299 nm로 여기 시킨 $Y_2MoO_6:Eu^{3+}$ 경우, 발광 세기가 가장 강한 611 nm의 주 피크를 방출하는 적색 스펙트럼이 관측되었으며, 함량이 0.01 mol에 0.2 mol로 증가함에 따라 611 nm의 주 적색 발광 스펙트럼의 세기가 증가하는 경향을 나타내었다. 파장 611 nm로 제어한 흡광 스펙트럼은 299 nm에 피크를 갖는 전하전달밴드 (CTB) 이었다 [그림 참조].

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2224-2226
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• 1997

공간벡터 펄스폭변조법과 관련하여 과변조시의 전류제어성능을 향상시킬 수 있는 벡터 과변조의 새로운 연산 알고리즘으로 유효전압벡터를 반지름으로 하는 원을 이용하여 수정된 기준전압벡터가 위치할 섹터를 구하고, 전압제한 6각형을 나타내는 전압벡터식을 이용하여 동일한 수식으로 벡터과변조하는 간결한 새로운 알고리즘을 제시하고, 이를 전류제어 시뮬레이션에 적용하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.3
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• pp.588-594
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• 1998

Reliable three-dimensional models of woven fabric composites had scarcely been proposed for their geometric complexity. Simplified models, mostly one- or two-dimensional, currently used are not considered effective enough because of their oversimplifications. In this paper, the equivalent thermal conductivities and elasticity properties of woven fabric composites are computed using homogenization technique. The computational results show that the strength and thermal conductivity linearly increase with fiber volume fraction and that the variations of undulation of fibers has little effect on equivalent material properties. Homogenization technique is proved useful in the study of woven fabric composites and may find a lot more applications in the area.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.6
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• pp.1169-1177
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• 2002

A study of fee vibration of circular Mindlin plates is presented. The analysis is based on the pseudospctral method, which uses Chebyshev polynomials and Fourier series as basis functions. It Is demonstrated that rapid convergence and accuracy as well as the conceptual simplicity could be achieved when the pseudospectral method was apt)lied to the solution of eigenvalue problems. Numerical examples of circular Mindlin plates with clamped and simply supported boundary conditions are provided for various thickness-to-radius ratios.

• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.4
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• pp.89-99
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• 2003

Smoothed particle hydrodynamics, SPH, is a gridless Lagrangian technique which is a useful alternative numerical analysis method to simulate high velocity deformation problems as well as astrophysical and cosmological problems. The SPH method brings about some difficulties such as tensile Instability and stress oscillation. A new SPH method, so called normalized algorithm, was introduced to overcome these difficulties. In this paper we aimed to estimate this method and have developed an one-dimensional normalized SPH program. The high velocity impact model of an aluminum bar has been analysed by using the developed program and a commercial hydrocode, LS-DYNA. The obtained numerical results showed good agreement with the results of the same model in reference. The program also showed more stable results than those of LS-DYNA in stress oscillation. We hopefully expect that the developed one-dimensional normalized SPH program can be used to solve hydrodynamic problems especially for explosive detonation analysis.