• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.3
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• pp.89-95
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• 1996

In this ppaer, temeprature dependent transport and heat transport models have been incorperated to the two dimensional device simulator SNU-2D provides a solid bse for nonisothermal device simulation. As an example to study the nonisothermal problem. we consider SOI MOSFET's I-V characteristics have been simulated and compared with the measurements. It is shown that negative slopes in the Ids-Vds characteristics are casused by the temperature dependence of the saturation velocity and the degradation of the temperature dependence mobility. Also it is shown that the kink effect occurs when impact ionization near the drain produces a buildup of holes in this isolated device island, and the hysteresis is caused by the creation of holes in the channel and their flow to the source.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.21-24
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• 2005

A computational analysis of hygro-thermal and mechanical behaviour of concrete column at high temperature is presented. The objective of this study is to develop a finite difference model that simulates coupled heat and transport phenomena in reinforced concrete structures exposed to rapid heating conditions such as fires. The theoretical basis for the integrated finite difference method is presented to describe a powerful numerical technique for solving of fluid flow in porous media. The numerical results predict the phenomena of 'moisture clog' and the explosive spalling of concrete under fire. The investigations show that high-strength concrete(HSC) and normal-strength concrete(NSC) exposed to high temperature have different pore pressure buildup dependent on porosity, permeability and moisture contents. HSC has more possibility than NSC on spalling.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1188-1191
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• 2009

In this study, cyclic triaxial tests were performed with the samples which were anisotropically consolidated using irregular earthquake loading to consider in-situ condition and seismic wave. The consolidation pressure ratio(K) was changed from 0.5 to 1.0. The Ofunato and Hachinohe wave are applied as irregular earthquake loading and liquefaction resistance strength was estimated from excess pore water pressure(EPWP) ratio. As results of the cyclic triaxial tests, buildup of EPWP ratio increased as K value increased. It shows, that the isotropically consolidated sands is more susceptible to liquefaction than anisotropically consolidated sands under equal conditions such as confining pressure and dynamic loading.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.349-352
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• 2001

The transient response in TDFA(Thulium-Doped Fiber Amplifier) is theoretically investigated. The TDFA has the spectral gain band in 1.47 ${\mu}{\textrm}{m}$. The transient model includes the transient buildup of the population inversion, the pump power, the signal power and their transient variation along the fiber amplifier. The results of numerical analysis can predict the gain saturation and recovery time at the fiber amplifier. It also shows the gain saturation and recovery effect depending on the pumping and saturation rate.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2227-2230
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• 2008

Crossover of nitrogen from cathode to anode is inevitable in typical membranes used in PEM fuel cells. This crossovered nitrogen accumulates in anode recirculation system and excessive buildup of nitrogen in the recirculating anode gas lowers the hydrogen concentration and finally affects the performance of fuel cell stacks. In this study, characterization of nitrogen gas crossover was investigated in PEM fuel cell stacks. The mass spectroscopy (MS) has been applied to measure the amount of the crossovered nitrogen at the exit of anode. Results show that anode and cathode stoichiometric number ($SR_c$) have a big effect of nitrogen crossover.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.1
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• pp.36-41
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• 2003

The purpose of this study was to find a way to lengthen the life of hot closed forging die. The fluid interpretation on the plastic deformation of billet of billet was performed by finite element method. And design modification on the impression shape was also performed. The defaced part on the impression surface was mended by the developed build-up welding method. The die life was 3,000 units but alter the procedure it was lengthened up to 5,000.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.90-93
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• 1987

Phase conjugate wavefront generation via real-time holography in degenerate four-wave mixing experiments in photo-refractive crystal $Bi_{12}$ Si $O_{20}$ is presented. Depending on the respective values of applied field $E_o$ and fringe spacing, drift or diffusion of the photecarriers dominates the space-charge buildup and affects the Phasa- Conjugate Wavefront intensity. The experimental results for wavefront reflectivity as a function of the intensity ratio of the writing beams agree with the theoretical predictions.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.4
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• pp.619-626
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• 2010

ROK Joint Chiefs of Staff in developing an WMA-EA(Warfighting Mission Area-Enterprise Architecture) tries to create the practical buildup requirements of military power through precise requirements and operational capabilities based on the architectures. However, it is difficult to verify the effectiveness of target architectures and do efficient requirement planning because we cannot know the gap of quantitative combat effectiveness between current and target WMA-EAs. This study presents an evaluation method of combat effectiveness and focuses on combat's positive effects in WMA-EAs. The method proposed is based on C2 model which is appropriate for the evaluation of combat effectiveness in architectures. We verify the effectiveness of the proposed method through a case study of an anti-ship warfare architecture.

• Proceedings of the Technology Innovation Conference
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• 2005.02a
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• pp.140-157
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• 2005

Industrial technological competitiveness is the major issue for many countries. therefore, many experts have concerned with how to measure competitiveness of industrial technologies. The purpose of this paper was to suggest the reasonable methodology of investigating competitiveness of industrial technologies. For such reasons, the technological competitiveness should analyzed on national, industrial an d firm level. In Korean case of the technological competitiveness has been assessed and analyzed industrial vision or target and looking for industrial demand survey for growing industries or requiring to investment of a large scale in dimension, such as 'Growing Engine Industries for Next Generation' However, it has not made a. thorough and systematic study on the assessment and analysis of the technological competitiveness, on this account developing of a systemic method and taking proper process of the technological competitiveness in industrial sector, and buildup the database system in adoptable real firms in sector. This paper will provide political counterproposal by surveying, assessing, and analyzing for technological competitiveness objectively through it can be leaded by technological innovations.

• Journal of the Korea Safety Management & Science
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• v.3 no.4
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• pp.19-34
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• 2001

Since the introduction of product liability law from America in 1960s, product liability has been on the rise as an important problem to the quality management of company and consumer's safety. Together with this, before the legislation of product liability system in Korea, the sense and level of company and consumer about product safety are rapidly changing, In times like the present, ensuring more systematic product safety and consumer safety, and the buildup need of competitive power in accordance with product liability prevention of company grows raising. Therefore, this study presents the most effectively manageable ways of product liability the side of safety management of consumers and companies through the ensuring ways and activity models of product safety and certification system in company.