• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.4
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• pp.244-258
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• 2019

The reliability of power electronic systems becomes increasingly important, as power electronic systems have gradually gained an essential status in a wide range of industrial applications. Accordingly, recent research has made an effort to improve the reliability of power electronic systems to comply with stringent constraints on safety, cost, and availability. The condition monitoring of power electronic components is one of the main topics in the research area of the reliability of power electronic systems. In this paper, condition-monitoring methods of reliability-critical components in power electronic systems are discussed to provide the current state of knowledge by organizing and evaluating current representative literature.

• Coupled systems mechanics
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• v.11 no.4
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• pp.297-313
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• 2022

The objective of this paper is to study the effect of frequency in a two-dimensional orthotropic thermoelastic rotating solid with fractional order heat transfer in generalized thermoelasticity with two-temperature due to inclined load. As an application the bounding surface is subjected to uniformly and linearly distributed loads (mechanical and thermal source). The problem is solved with the help of Fourier transform. Assuming the disturbances to be harmonically time dependent, the expressions for displacement components, stress components, conductive temperature and temperature change are derived in frequency domain. Numerical inversion technique has been used to determine the results in physical domain. The results are depicted graphically to show the effect of frequency on various components. Some particular cases are also discussed in the present research.

• ETRI Journal
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• v.41 no.1
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• pp.23-31
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• 2019

Since the late 20th century, there has been rapid development in the display industry. Only 30 years ago, we used big cathode ray tube displays with poor resolution, but now most people use televisions or smartphones with very high-quality displays. People now want images that are more realistic, beyond the two-dimensional images that exist on the flat screen, and digital holography-one of the next-generation displaysis expected to meet that need. The most important parameter that determines the performance of a digital hologram is the pixel pitch. The smaller the pixel pitch, the higher the level of hologram implementation possible. In this study, we fabricated the world-smallest $3-{\mu}m$-pixel-pitch holographic backplane based on the spatial light modulator technology. This panel could display images with a viewing angle of more than $10^{\circ}$. Furthermore, a comparative study was conducted on the fabrication processes and the corresponding holographic results from the large to the small pixel-pitch panels.

• ETRI Journal
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• v.38 no.4
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• pp.665-674
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• 2016

We designed and fabricated a semiconductor optical amplifier-integrated dual-mode laser (SOA-DML) as a compact and widely tunable continuous-wave terahertz (CW THz) beat source, and a pin-photodiode (pin-PD) integrated with a log-periodic planar antenna as a CW THz emitter. The SOA-DML chip consists of two distributed feedback lasers, a phase section for a tunable beat source, an amplifier, and a tapered spot-size converter for high output power and fiber-coupling efficiency. The SOA-DML module exhibits an output power of more than 15 dBm and clear four-wave mixing throughout the entire tuning range. Using integrated micro-heaters, we were able to tune the optical beat frequency from 380 GHz to 1,120 GHz. In addition, the effect of benzocyclobutene polymer in the antenna design of a pin-PD was considered. Furthermore, a dual active photodiode (PD) for high output power was designed, resulting in a 1.7-fold increase in efficiency compared with a single active PD at 220 GHz. Finally, herein we successfully show the feasibility of the CW THz system by demonstrating THz frequency-domain spectroscopy of an ${\alpha}$-lactose pellet using the modularized SOA-DML and a PD emitter.

• Journal of Korea Game Society
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• v.16 no.3
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• pp.45-54
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• 2016

This study analyzes cable TV Program "From Start to Till the End" televised by ONGAMENET from 2009 to 2015. "From Start to Till the End" is a game program that guests try to finish certain game or to complete mission once they started. Unlike other game programs, most of guests are not professional gamers thus it brings out comical challenges and enjoyments. This study examines the several components of video games played in the program. Specifically, those components are categorized according to the genre, platform, nationality, and clear time. In doing so, this study not only unpacks diverse structures of the program but also provides the blueprint of the game program.

• Nuclear Engineering and Technology
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• v.46 no.5
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• pp.655-666
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• 2014

The CUPID code has been developed at KAERI for a transient, three-dimensional analysis of a two-phase flow in light water nuclear reactor components. It can provide both a component-scale and a CFD-scale simulation by using a porous media or an open media model for a two-phase flow. In this paper, recent advances in the CUPID code are presented in three sections. First, the domain decomposition parallel method implemented in the CUPID code is described with the parallel efficiency test for multiple processors. Then, the coupling of CUPID-MARS via heat structure is introduced, where CUPID has been coupled with a system-scale thermal-hydraulics code, MARS, through the heat structure. The coupled code has been applied to a multi-scale thermal-hydraulic analysis of a pool mixing test. Finally, CUPID-SG is developed for analyzing two-phase flows in PWR steam generators. Physical models and validation results of CUPID-SG are discussed.

• Journal of Internet Computing and Services
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• v.13 no.4
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• pp.73-82
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• 2012

The worldwide increase of cognitive surplus leads to successful social authoring projects. In this research, social authoring mechanisms used in Linux and Wikipedia projects were analyzed to identify the key success factors. In addition, tools used in the recent successful social media such as Facebook and Ushahidi were evaluated to extract components which may be applied in social authoring systems. Based on these analyses, the improvement factors in the design of social authoring projects were suggested. The social authoring projects are expected to be more successfully achieved by providing the core components proposed in this article.

• Korean Journal of Microbiology
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• v.42 no.3
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• pp.172-176
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• 2006

In order to increase the productivity of lipstatin by Steptomyces toxytricini, the effect of medium components on the lipstatin production was investigated. Using TSB medium as a basal medium, a variety of carbon sources, nitrogen sources, lipid and fatty acids was supplemented into a fermentation medium. The seed culture of S. toxytricini grown in 25 ml TSB medium at $28^{\circ}C$ for 3 days with agitation at 200 rpm was inoculated in the size of 2% in fermentation media containing different components and fermented at $28^{\circ}C$ for 60 more hrs. In the examination of the effect of carbon sources, the best cell growth was observed in fermentation media supplemented with glucose or glycerol, but the lipstatin productivity was the highest in media containing lactose or sucrose. Among complex nitrogen sources, yeast extract was the best one for cell growth, but the highest lipstatin production was found in TSB media composed of 1.7% casitone and 0.3% soytone. The increased concentration of triolein as a lipid caused the promotion of cell growth but the significant suppression of lipstatin production. When 0.5% fatty acids were supplemented to fermentation medium, unsaturated fatty acids like linoleic or oleic acid suppressed cell growth as well as lipstatin production, but 2 times higher lipstatin production was achieved by stearic acid, a saturated fatty acid, differently from expectation.

• KSBB Journal
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• v.4 no.2
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• pp.162-166
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• 1989

When various strains of Streptomyces griseus and S. galbus were examined for the ability on the production of streptomycin in tryptic soy(TS) broth, S. griseus ATCC 27001 was found to be the best. S. griseus ATCC 12475 and ATCC 23345 showed also good growth and favorable production of streptomycin. Examination of various complex media reported in fermentation literatures for the industrial production of streptomycin indicated that glucose-soybean media-sodium chloride (GSS) broth and K (Chucken) broth gave higher yields of streptomycin than others studied by us. Examination of the ingredients of media producing streptomycin in high yield indicated that some components in soybean activated the production of streptomycin. Addition of meat extract enhanced the yield of streptomycin but it could be substituted with distillers solubles without much effect on the yield. Addition of corn steep liquor decreased the production of streptomycin.

• Computers and Concrete
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• v.25 no.3
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• pp.205-214
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• 2020

Cytoskeleton components in living cell bear large compressive force and are responsible in maintaining the cell shape. Actually these filaments are surrounded by viscoelastic media within the cell. This surrounding, viscoelastic media affects the buckling behavior of these filaments when external force is applied on these filaments by exerting continuous pressure in opposite directions to the incipient buckling of the filaments. In this article a mechanical model is applied to account the effects of this media on the buckling behavior of intermediate filaments network of cytoskeleton. The model immeasurably associates; filament's bending rigidity, adjacent system elasticity, and cytosol viscosity with buckling wavelength, buckling growth rate and buckling amplitude of the filaments.