• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.486-489
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• 2002

Temperature(T) dependence of the sheet resistance( $R_{$\square$}$) has been investigated on the c-axis oriented thin films of the (Bi2212/Bi2201) mixed crystal with different molar fractions. The $R_{$\square$}$-T superconducting characteristic deteriorated with reduction of the Bi2212 fraction, and almost disappears at 48 mol% where a superconductor-to-insulator transition took place, with the resistance on the normal state, RN, reaching 4.l㏀ at 80 K. This $R_{N}$ value is close to the universal quantum number, h/(2e)$^2$≡6.5㏀ predicted by the Kosterlitz-Thouless(KT) transition theory. The $R_{$\square$}$-T characteristics of the 48 mol% thin film can be elucidated as a competitive process of KT transition brought about by charge or vortex in the two-dimensional layer structure.e.

• Transactions on Electrical and Electronic Materials
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• v.3 no.2
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• pp.20-23
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• 2002

Temperature (T) dependence of the sheet resistance (R$\_$$\square$/) has been investigated an the c-axis oriented thin films of the (Bi2212/Bi2201) mixed crystal with different molar fractions. The R$\_$$\square$/-T superconducting characteristic deteriorated with reduction of the Bi2212 fraction, and almost disappears at 48 mol% where a superconductor-to-insulator transition too k place, with the resistance on the normal state, R$\_$N/, reaching 4.1 kΩka at 80 K. This R$\_$$\square$/ value is close to the universal quantum number, h/(2e)$_2$≡ 6.5 kΩ predicted by the Kosterlitz-Thouless (KT) transition theory. The R$\_$$\square$/-T characteristics of the 48 mol% thin film can be elucidated as a competitive process of KT transition brought about by charge or vortex in the two-dimensional layer structure.

• ETRI Journal
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• v.30 no.2
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• pp.261-267
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• 2008

In this paper, we propose and demonstrate a cost-effective technique to upgrade the capacity of dense wavelength division multiplexing (DWDM) networks to a 40 Gb/s line rate using the existing 10 Gb/s-based infrastructure. To accommodate 40 Gb/s over the link optimized for 10 Gb/s, we propose applying a combination of super-FEC, carrier-suppressed return-to-zero, and pre-emphasis to the 40 Gb/s transponder. The transmission of 40 Gb/s DWDM channels over existing 10 Gb/s line-rate long-haul DWDM links, including $40{\times}40$ Gb/s transmission over KT's standard single-mode fiber optimized for 10 Gb/s achieves successful results. The proposed upgrading technique allows the Q-value margin for a 40 Gb/s line rate to be compatible with that of 10 Gb/s.

• Journal of the Korean Chemical Society
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• v.49 no.3
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• pp.247-254
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• 2005

• Atmosphere
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• v.18 no.3
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• pp.159-169
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• 2008

The characteristics of the typhoon's extratropical transition (ET) over the western North Pacific area were investigated using the cyclone phase space (CPS) diagram method suggested by Hart (2003). The data used in this study were the global data assimilation prediction system (GDAPS) and NCEP data set. The number of typhoons selected were 75 cases during 2002 to 2007, and the three parameters were analyzed : the motion relative thickness asymmetry of the storm (B), the upper thermal wind shear and the lower thermal wind shear. Comparing the best-track data provided by the Regional Specialized Meteorological Center /Tokyo, the time of the ET based on CPS was 2~6 hours earlier than the best-track data. And it was shown that the 400- km and 30 kt wind radius of storm for the CPS method were better agreement than the previous suggested radius 500- km.

• The Journal of Bigdata
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• v.4 no.2
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• pp.13-22
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• 2019

This study was conducted with funding from the government (Ministry of Agriculture, Food and Rural Affairs) in 2018 with support from the Agricultural, Food, and Rural Affairs Agency, 318069-03-HD040, and is based on artificial intelligence-based HPAI spread analysis and patterning. The inflow of highly pathogenic avian influenza is coming through migratory birds from abroad, but it is not known exactly what pathways provide the farm with the cause of the infection. And the transition between farms from the generated farms only assumes that the vehicle is the main cause, and the main cause of the spread is not exactly known. Based on the call detailed records (CDR) data provided by KT, the study aims to see how people visiting migratory bird-watching sites, presumed to be the site of the outbreak, will flow through infected farms.

• Transactions on Electrical and Electronic Materials
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• v.3 no.2
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• pp.32-37
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• 2002

This paper gives the basic mechanical properties of indium-tin-oxide (ITO) films on polymer substrates which are exposed to externally and thermally induced bending force. By using modified Storney formula including triple layer structure and bulge test measuring the conductive changes of patterned ITO islands as a function of bending curvature, the mechanical stability of ITO films on polymer substrates was intensively investigated. The numerical analyses and experimental results show thermally and externally induced mechanical stresses in the films are responsible for the difference of thermal expansion between the ITO film and the substrate, and leer substrate material and its thickness, respectively. Therefore, a gradually ramped heating process and an organic buffer layer were employed to improve the mechanical stability, and then, the effects of the buffer layer were also quantified in terms of conductivity-strain variations. As a result, it is uncovered that a buffer layer is also a critical factor determining the magnitude of mechanical stress and the layer with the Young's modulus lower than a specific value can contribute to relieving the mechanical stress of the films.

• Journal of the Korean Ceramic Society
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• v.25 no.4
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• pp.321-328
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• 1988

The sintering phenomena, electrical resistivity, dielectric and piezoelectric properties of lead titanate ceramics modified by the partial substitution of La for Pb and Mn for Ti, (Pb1-1.5xLax)(Ti1-yMny)O3 ceramics, have been investigated. In (Pb1-1.5xLax)(Ti1-yMny)O3 system, with increasing lanthanum content, the realtive bulk density increased, but the Curie point and tetragonality (c/a) decreased. The tetragonal-to-cubic phase transition boundary existed in the range of 0.20

• Journal of Multimedia Information System
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• v.9 no.2
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• pp.93-102
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• 2022

Dependency parsing is a decision problem of the syntactic relation between words in a sentence. Recently, deep learning models are used for dependency parsing based on the word representations in a continuous vector space. However, it causes a mislabeled tagging problem for the proper nouns that rarely appear in the training corpus because it is difficult to express out-of-vocabulary (OOV) words in a continuous vector space. To solve the OOV problem in dependency parsing, we explored the proper noun embedding method according to the embedding unit. Before representing words in a continuous vector space, we replace the proper nouns with a special token and train them for the contextual features by using the multi-layer bidirectional LSTM. Two models of the syllable-based and morpheme-based unit are proposed for proper noun embedding and the performance of the dependency parsing is more improved in the ensemble model than each syllable and morpheme embedding model. The experimental results showed that our ensemble model improved 1.69%p in UAS and 2.17%p in LAS than the same arc-eager approach-based Malt parser.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8B
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• pp.699-706
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• 2003

This paper is to verify that 2-state MMPP Model conform to ATM VBR traffic characteristics by measuring and analyzing real-time VBR traffic in KT's ATM network. As a result, we validated the fact that real-time VBR traffic of ATM network cannot be apply to MMPP model and must be represented by previously general On-Off Model with characteristics as follows: arrival rate of On state (λ$_1$) is deterministic, arrival rate of Off state (λ$_2$) is zero, and two transition rate (T$_1$,T$_2$) is only random variable. As research results are to handle real traffic, these results can be used to all ATM network traffic model with traffic management function such as KT's ATM network.