• Transactions of the Korean hydrogen and new energy society
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• v.7 no.1
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• pp.19-28
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• 1996

Ti-Mn based hydrogen storage alloy were modified by substituting alloying elements such as Zr, V and Ni in order to design a high capacity MH electrode for Ni/MH rechargeable battery. When V was substituted in Ti-Mn binary system, the crystal structure was maintained as $Cl_4$ Laves phase at a composition of $Ti_{0.2}V_{0.4}Mn_{0.4}$ and $Ti_{0.4}V_{0.2}Mn_{0.4}$ and equilibrium pressure decreased below 1 atm without decreasing hydrogen storage capacity considerably. It was found that Ni should be included in Ti-V-Mn alloy in order to hydrogenate it electrochemically in KOH electrolyte. But substitution of Ni for Mn in Ti-V-Mn system caused the increase of equilibrium pressure above 1atm and decrease of hydrogen storage capacity. Zr was able to increase the reversible hydrogen storage capacity of Ti-V-Mn-Ni alloy without considerable change of hydrogenation properties. The electrochemical discharge capacity of Ti-Zr-V-Mn-Ni system were in the range of 350 - 464mAh/g and among them $Ti_{0.8}Zr_{0.2}V_{0.5}Mn_{0.5}Ni_{1.0}$ alloy had $Cl_4$ Laves single phase and very high electrochemical discharge capacity of 464mAh/g.

• Journal of the Korean Data and Information Science Society
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• v.26 no.1
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• pp.89-99
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• 2015

The World Economic Forum and the Korean Ministry of Knowledge Economy have selected big data as one of the top 10 in core information technology. The key of big data is to analyze effectively the properties that do have data. Clustering analysis method of big data techniques is a method of assigning a set of objects into the clusters so that the objects in the same cluster are more similar to each other clusters. Similarity measures being used in the cluster analysis may be classified into various types depending on the nature of the data. In this paper, we studied upper and lower bounds for binary similarity measures with negative matches such as Russel and Rao measure, simple matching measure by Sokal and Michener, Rogers and Tanimoto measure, Sokal and Sneath measure, Hamann measure, and Baroni-Urbani and Buser mesures I, II. And the comparative studies with these measures were shown by real data and simulated experiment.

• BMB Reports
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• v.38 no.5
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• pp.584-590
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• 2005

Glucose 6-phosphate dehydrogenase (EC 1.1.1.49) was purified from Aspergillus aculeatus, a filamentous fungus previously isolated from infected tongue of a patient. The enzyme, apparently homogeneous, had a specific activity of $220\;units\;mg^{-1}$/, a molecular weight of $105,000{\pm}5,000$ Dal by gel filtration and subunit size of $52,000{\pm}1,100$ Dal by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The substrate specificity was extremely strict, with glucose 6-phosphate (G6P) being oxidized by nicotinamide adenine dinucleotide phosphate (NADP) only. At assay pH of 7.5, the enzyme had $K_m$ values of $6\;{\mu}m$ and $75\;{\mu}m$ for NADP and G6P respectively. The $k_{cat}$ was $83\;s^{-1}$. Steady-state kinetics at pH 7.5 produced converging linear Lineweaver-Burk plots as expected for ternary-complex mechanism. The patterns of product and dead-end inhibition suggested that the enzyme can bind NADP and G6P separately to form a binary complex, indicating a random-order mechanism. The enzyme was irreversibly inactivated by heat in a linear fashion, with G6P providing a degree of protection. Phosphoenolpyruvate (PEP), adenosinetriphosphate (ATP), and fructose 6-phosphate (F6P), in decreasing order, are effective inhibitors. Zinc and Cobalt ions were effective inhibitors although cobalt ion was more potent; the two divalent metals were competitive inhibitors with respect to G6P, with $K_i$ values of $6.6\;{\mu}m$ and $4.7\;{\mu}m$ respectively. It is proposed that inhibition by divalent metal ions, at low NADPH /NADP ratio, is another means of controlling pentosephosphate pathway.

• 전자공학회논문지 IE
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• v.46 no.4
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• pp.16-24
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• 2009

In this paper, we propose a new noise cancellation system for the NDIR based optical analyzer, that can measure various environmental air-pollution materials (CO, $SO_2$, NOx, etc.) in real-time. The sensed signals are contaminated by the different noise sources that measurement noise with high frequencies and the drift noise with the low frequencies. They can be eliminated by a pre-processing that considering their time-domian properties and by a post-processing that using sub-power ratios in subband structure. In the proposed method, the ore and pose-processing for noise cancelling are useful for hardware implementation of the NDIR based optical analyzer with a precision measuring.

• Journal of the Korean Ceramic Society
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• v.34 no.1
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• pp.70-78
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• 1997

3Y-TZP/SUS316 Functionally Graded Material (FGM) was fabricated by slip casting method. Alumina mold was used to overcome problems of gypsum mold in slip casting process, and the optimal dispersion con-ditions of 3Y-TZP/SUS316 binary slurries was determined using electrokinetic sonic amplitude and a viscometer, and observing sedimentation behavior. The properties of the specimens casted by gypsum mold and alumina mold were compared in terms of changes in shrinkage rate, drying and sintering conditions, and microstructure. It was found that the specimens obtaine from the alumina mold showed a clean surface, easier thickness control of each layer, and higher productivity. Especially, no degradation was observed in the SUS316 prepared using alumina mold. Thus it is desirable to use porous alumina mold rather than gyp-sum mold for the slip casting of 3Y-TZP/SUS316-FGM.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.2
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• pp.245-251
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• 2008

Although many studies have been carried out about binary gas mixtures with $SF_6$, few studies were presented about breakdown characteristics of $SF_6/CF_4$ mixtures. At present study the breakdown characteristics of $SF_6/CF_4$ mixtures in non-uniform field was performed. The experiments were carried out under AC voltage and standard lightning impulse(SLI) voltage. Breakdown characteristics were investigated for $SF_6/CF_4$ mixtures when AC voltages and standard lighting impulse voltage was applied in a needle-plane. The needle-plane electrode whose gap distance was 3 mm were used in a test chamber. $SF_6/CF_4$ mixtures contained from 0 to 100% $SF_6$ and the experimental gas pressure ranged from 0.1 to 0.5 MPa. The breakdown characteristics of $SF_6/CF_4$ mixtures in non-uniform field may be influenced by defects like needle-shaped protrusions. In case of slowly rising SLI voltage and AC voltage it is enhanced by corona-stabilization. This phenomena caused by the ion drift during streamer development and the resulting space-charge is investigated. In non-uniform field under negative SLI voltage the breakdown voltage was increase linearly but under positive SLI voltage the breakdown voltage increase non-linearly. The breakdown voltage in needle-plane electrode displayed N shape characteristics for increasing the content of $SF_6$ at AC voltage. $SF_6/CF_4$ mixture has good dielectric strength and arc-extinguishing properties than pure SF6. This paper presents experimental results on breakdown characteristics for various mixtures of $SF_6/CF_4$ at practical pressures. We could make an environment friendly gas insulation material with maintaining dielectric strength by combing $SF_6\;and\;CF_4$ which generates a lower lever of the global warming effect.

• Journal of KIISE:Software and Applications
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• v.26 no.10
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• pp.1247-1259
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• 1999

본 논문에서는 한국어 문장형성원리를 간결하게 제시할 수 있도록 X-바 이론의 중심어 개념을 도입한 한국어 자질기반 문법을 제안한다. 제안하는 문법은 어절에 관계없이 나타나는 한국어의 문법현상을 명확히 설명할 수 있도록 어절 대신 형태소를 기본단위로 한다. 그리고, 한국어의 구문범주가 지닌 의미정보와 기능정보를 자질을 이용하여 독립적으로 표현하며, 구문범주간의 결합관계를 바탕으로 하는 자질연산을 수행하여 문장을 분석한다. 또한, 한국어의 부분자유어순과 생략현상에 대해 견고하게 분석할 수 있도록 자질연산을 이진결합중심의 CNF(Chomsky Normal Form)로 제한한다. 이렇게 구성된 한국어 자질기반 문법은 규칙을 직관적이고도 간단하게 기술하며, 한국어의 다양한 문장들을 견고하게 분석한다. SERI Test Suites 97과 신문기사에서 746문장을 추출하여 실험한 결과 94%~99%의 적용율을 보였다.Abstract In this paper, we propose a Korean feature-based grammar(KFG) which adopts the X-bar theoretic notion of headedness for a precise representation of Korean syntactic structure. In order to explain various language phenomena in a given sentence, we use not the word but the morpheme as a constituent unit of KFG. We use features manifesting both the syntactic information and the semantic information of Korean syntactic categories, and feature operations based on the association relationship between two categories. In addition, we restrict feature operations to CNF(Chomsky Normal Form) binary form, which provides a robust representation for properties in Korean such as the frequent ellipsis and the partial free-order. The KFG is intuitive, simple, and versatile in representing most Korean sentences. The experimental result shows 94%~99% coverage on 746 sentences extracted from SERI Test Suites 97 and newspaper sentences.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.199-199
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• 2011

Recently, Thin film transistors (TFTs) with amorphous oxide semiconductors (AOSs) can offer an important aspect for next generation displays with high mobility. Several oxide semiconductor such as ZnO, $SnO_2$ and InGaZnO have been extensively researched. Especially, as a well-known binary metal oxide, tin oxide ($SnO_2$), usually acts as n-type semiconductor with a wide band gap of 3.6eV. Over the past several decades intensive research activities have been conducted on $SnO_2$ in the bulk, thin film and nanostructure forms due to its interesting electrical properties making it a promising material for applications in solar cells, flat panel displays, and light emitting devices. But, its application to the active channel of TFTs have been limited due to the difficulties in controlling the electron density and n-type of operation with depletion mode. In this study, we fabricated staggered bottom-gate structure $SnO_2$-TFTs and patterned channel layer used a shadow mask. Then we compare to the performance intrinsic $SnO_2$-TFTs and doping hafnium $SnO_2$-TFTs. As a result, we suggest that can be control the defect formation of $SnO_2$-TFTs by doping hafnium. The hafnium element into the $SnO_2$ thin-films maybe acts to control the carrier concentration by suppressing carrier generation via oxygen vacancy formation. Furthermore, it can be also control the mobility. And bias stability of $SnO_2$-TFTs is improvement using doping hafnium. Enhancement of device stability was attributed to the reduced defect in channel layer or interface. In order to verify this effect, we employed to measure activation energy that can be explained by the thermal activation process of the subthreshold drain current.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.11C
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• pp.1140-1151
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• 2003

This paper proposes a face recognition method based on modified Otsu's binarization and Hu moment. Proposed method is robust to brightness, contrast, scale, rotation, and translation changes. As the proposed modified Otsu's binarization computes other thresholds from conventional Otsu's binarization, namely we create two binary images, we can extract higher dimensional feature vector. Here the feature vector has properties of robustness to brightness and contrast changes because the proposed method is based on Otsu's binarization. And our face recognition system is robust to scale, rotation, and translation changes because of using Hu moment. In the perspective of brightness, contrast, scale, rotation, and translation changes, experimental results with Olivetti Research Laboratory (ORL) database and the AR database showed that average recognition rates of conventional well-known principal component analysis (PCA) are 93.2% and 81.4%, respectively. Meanwhile, the proposed method for the same databases has superior performance of the average recognition rates of 93.2% and 81.4%, respectively.

• Journal of Communications and Networks
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• v.13 no.6
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• pp.602-611
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• 2011

The inter-domain routing scalability issue is a major challenge facing the Internet. Recent wide deployments of multihoming and traffic engineering urge for solutions to this issue. So far, tunnel-based proposals and compact routing schemes have been suggested. An implicit assumption in the routing community is that structured address labels are crucial for routing scalability. This paper first systematically examines the properties of identifiers and address labels and their functional differences. It develops a simple Internet routing model and shows that a binary relation T defined on the address label set A determines the cardinality of the compact label set L. Furthermore, it is shown that routing schemes based on flat address labels are not scalable. This implies that routing scalability and routing stability are inherently related and must be considered together when a routing scheme is evaluated. Furthermore, a metric is defined to measure the efficiency of the address label coding. Simulations show that given a 3000-autonomous system (AS) topology, the required length of address labels in compact routing schemes is only 9.12 bits while the required length is 10.64 bits for the Internet protocol (IP) upper bound case. Simulations also show that the ${\alpha}$ values of the compact routing and IP routing schemes are 0.80 and 0.95, respectively, for a 3000-AS topology. This indicates that a compact routing scheme with necessary routing stability is desirable. It is also seen that using provider allocated IP addresses in multihomed stub ASs does not significantly reduce the global routing size of an IP routing system.