• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.11a
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• pp.276-277
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• 2010

Web2.0의 고도화와 소셜미디어의 진화에 따라 웹 기반 콘텐츠에 대한 다양한 활용이 시도되고 있다. 또한, IPTV 부분에서는 기존의 TV기반에서 Web기반, Mobile기반 서비스로 확산되고 있다. 이러한 멀티디바이스 환경과 웹기반 콘텐츠의 IPTV 활용 서비스를 위해서는 콘텐츠에 대한 정의와 이를 표현하기 위한 메타데이터에 대한 정의가 필요하다. 이를 위해서 관련 표준화 단체를 분석한 후 이들이 제공하는 콘텐츠 메타데이터의 연관관계를 비교 분석하였다. IPTV 서비스를 위한 콘텐츠 메타데이터는 TV AnyTime Phase1 을 바탕으로 각 표준기구의 네트워크 상황과 서비스 방식에 따라 선택적으로 적용하고 있으며, VOD 서비스를 위해서는 CableLab의 ADI 메타데이터를 적용하고 있다. 향후 멀티디바이스 환경에서 IPTV 서비스를 위해서는 메타데이터에 대한 확장 연구가 필요하다.

• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1381-1385
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• 2006

Cobalt (cyclam) complex has been successfully immobilized onto SBA-15, and proven to be an active catalyst for the epoxidation of styrene with tert-butyl hydroperoxide as a terminal oxidant. The selectivity for styrene oxide was observed to be up to 66% with 40% styrene conversion after 12h reaction time. The reversible redox cycle between Co(III) and Co(II) couple which was supposed to play key role during the epoxidation reaction was supported by a cyclic voltametry analysis. The textural properties of the catalyst was characterized by XRD, N2 adsorption-desorption, and TEM analysis.

• Journal of Industrial Technology
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• v.17
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• pp.183-189
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• 1997

The computation of the flow around a supercritical airfoil with a divergent trailing edge(DTE) modification(DLBA 243) is compared to that of original supercritical airfoil(DLBA 186). For this computation, Reynolds-Averaged Navier-Stokes equations are solved with a linearized block implicit ADI method and a mixing length turbulence model. Results show the effects of the shock and separated flow regions on drag reduction due to DTE modification. Results also show that DTE modification accelerates the boundary layer flow near the trailing edges which has an effect similar to a chordwise extension that increases circulation and is consistent with the calculated increase in the recirculation region in the wake. Airfoil with DTE modification achieves the same lift coefficient at a lower incidence and thus at a lower drag coefficient, so that lift-to-drag ratio is increased in transonic cruise conditions compared to the original airfoil. The reduction in drag due to DTE modification is associated with weakening of shock strength and delay of shock which is greater than the increase in base drag.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.6
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• pp.2835-2850
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• 2016

RSA is a public key cryptosystem that is currently the most popularly used in information security. Development of RSA variants has attracted many researchers since its introduction in 1978 by Ron Rivest, Adi Shamir, and Leonard Adleman. In this paper, we propose an algebraic structure for RSA and show that the proposed structure covers all known RSA variants. The usefulness of the proposed structure is then proved by showing that, following the structure we can construct a RSA variant based on the Bergman ring. We compare the original RSA and its variants from the point of view of factoring the modulus to determine why the original RSA is widely used than its variants.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.2
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• pp.153-160
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• 2000

A Particle Image Velocimetry(PIV) algorithm is developed to analyze whole flow field both qualitatively and quantitatively. The practical use of PIV requires the use of fast, reliable, computer-based methods for tracking numerous particles suspended in a flow field. The TSS, NTSS, FFT-Hybrid, which are developed in the area of image compression and coding, are introduced to develop fast vector search algorithm. The numerical solution of the lid-driven cavity flow by the ADI algorithm with the Wachspress Formula is introduced to produce synthetic data for the validation of the tracking algorithms. The algorithms are applied to image data of real flow experiments. The comparisons in CPU time and mean error show, with a small loss of accuracy, CPU time for tracking is reduced considerably.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2005.09a
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• pp.183-187
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• 2005

In this paper, we propose a heuristic method to select features using a Two-Phase Markov Blanket-based (TPMB) algorithm. The first phase, filtering phase, of TPMB algorithm works by filtering the obviously redundant features. A non-linear correlation method based on Information theory is used as a metric to measure the redundancy of a feature [1]. In second phase, approximating phase, the Markov Blanket (MB) of a system is estimated by employing the concept of cross entropy to identify the MB. We perform experiments on microarray data and report two popular dataset, AML-ALL [3] and colon tumor [4], in this paper. The experimental results show that the TPMB algorithm can significantly reduce the number of features while maintaining the accuracy of the classifiers.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.7
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• pp.2347-2355
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• 1996

Purpose of the present study is to develop a computational design program for shape optimization, combining the numerical optimization technique with the flow analysis code. The present methodology is then validated in three cases of aerodynamic shape optimization. In the numerical optimization, a feasible direction optimization algorithm and shape functions are considered. In the flow analysis, the Navier-Stokes equations are discretized by a cell-centered finite volume method, and Roe's flux difference splitting TVD scheme and ADI method are used. The developed design code is applied to a transonic channel flow over a bump, and an external flow over a NACA0012 airfoil to minimize the wave drag induced by shock waves. Also a separated subsonic flow over a NACA0024 airfoil is considered to determine a maximum allowable thickness of the airfoil without separation.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.516-518
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• 2003

This study discusses an effort to build a model to link normalized difference vegetation indices (NDVI) and socio-economic indicators derived from village survey (1990, 1993, 1996, and 2000) statistical data in Bekasi, West Java, Indonesia. Socio-economics indicators of sub-district level, in this study the number of agricultural households (AH), are aggregated from village level data. NDVI from Landsat-TM resolution data (1989 and 1997) are computed to detect land use/land cover (LULC) dynamics in the sub-district areas. Attention is mainly paid on the examination of agricultural land cover changing in the sub-district level. NDVI measurements might be used to predict AH dynamics as showed by computed linear regression models.

• Proceedings of the Korea Water Resources Association Conference
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• 1989.07a
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• pp.123-132
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• 1989

자연하천에서의 흐름특성을 해석하기 위해 Boundary - fitted(BF) coordinate system을 응용하여 유한차분법에 의한 2차원모델을 개발하였다. BF coordinates는 경계면의 형상에 관계없이 적용할 수 있으며 모든 계산은 기본식의 좌표변환을 통해 직각좌표계에서 행해지므로 경계조건의 입력에 용이하다. Physical domain(X - Y 좌표계)에서 하천의 형상을 입력하면 Grid generation에 의해 모든 계산은 Computational domain($\varepsilon$ - n 좌표계)에서 행해진다. Computational domain에서의 유한차분법은 half - time step으로 ADI 방법을 이용했고, 한 방향의 유속과 수위를 Double sweep으로 풀었다. 유속, 수위 및 하상의 격점망은 Staggered grid system을 사용했으며 geometric elements는 각 격점별로 계산하였다. 본 모델을 이용하므로써 불규칙한 수로나 하천의 흐름상태를 해석할 수 있으므로 흐름의 종단, 횡단방향의 유속분포, Superelevation을 구할 수 있고 하천의 계획, 관리, 제방의 호안이나 구조물의 설치등으로 일어나는 수리학적 영향등을 예측할 수 있다.

• Korean Journal of Microbiology
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• v.23 no.3
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• pp.235-240
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• 1985

A total of 10 main characters of 16 species of family Rhodospirllaceae were phenetically and cladistically analyzed by Farris' method. The obtained phenogram and cladistic tree were compared with Bergey's manual and other papers. The results supported that the system of 5 subgroups (genera) is available in family Rhodospirllaceae and indicated that close affinities between Rhodospirllum tenue and Rhodopseudomonas gelatinosa and between Rhodomicrobium vannielii and other species of genus Rhodopseudomonas were proved.