• Journal of Aerospace System Engineering
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• v.13 no.2
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• pp.51-59
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• 2019

Subsequently, Part I [1], which was about the single-cell model, a composite thin-walled beam with a multi-cell of chord-wise asymmetric cross-section, was selected in this study. Moreover, the theoretical dynamic characteristics of the model were analyzed. For this analysis, mathematical modeling was performed by considering the warping restraint effects, transverse shear effects, taper ratio and cross-section ratio. Similar to part I, the mass, stiffness coefficients and Eigen frequencies of the multi-cell section considered were investigated. In particular, the comparison between the multi-cell and single-cell sections and the effects of the cross-section ratio and taper ratio of the model on the Eigen frequencies were analyzed. However, the results compared when the asymmetry of the section was considered and warping function were not corrected.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.6
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• pp.842-851
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• 2011

A multi-cell test system with 25 independent cells is used to test different electrode materials simultaneously for polymer electrolyte membrane fuel cells (PEMFCs). Twenty-five segmented membrane electrode assemblies (MEAs) having the same or different Pt-loading are prepared to analyze the performance deviation of cells in the multi-cell test system. Improvements in the multi-cell test system are made by ensuring that the system performs voltage sensing for the cells individually and inserting optimum gaskets between the MEAs and the graphite plates. The cell performances are improved and their deviations are significantly decreased by these modifications. The performance deviations changed according to various cell configurations because the operating conditions of the cells, such as the gas flow and concentration, differed. This cell system can be used to test multiple electrodes simultaneously because it shows relatively uniform performance under the same conditions as well as linear correlation with various catalyst loadings.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.5A
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• pp.421-428
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• 2009

Inter-cell coordination has been an emerging issue for mitigating inter-cell interference in broadband wireless access networks such as IEEE802.16 and 3GPP LTE (Long Term Evolution). This paper proposes uplink/downlink hybrid inter-cell coordination patterns for a TDD (Time Division Duplex)/MC-CDMA (Multi-Carrier Code Division Multiple Access) system. For the performance analysis, closed forms of inter-cell interferences are derived when uplink and downlink transmissions coexist over a multi-cell environment. In the analysis, we find an optimal ratio of downlink transmit powers of BSs (Base Stations) based on the target outage probability and the performance according to ratios of uplink/downlink transmit powers of MSs (Mobile Stations)/BSs is explored. Our numerical results show that interference mitigation utilizing the characteristics of the uplink and downlink power ratio is very effective in improving system performance in terms of QoS.

• Journal of Information Processing Systems
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• v.15 no.1
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• pp.47-54
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• 2019

This study is concerned with the mechanism and structure of an optical microscope and an automatic multi-focus algorithm for automatically selecting sharp images from multiple foci of a cell. To obtain precise cell images quickly, a z-axis actuator with a resolution of $0.1{\mu}m$ was designed to control an optical microscope Moreover, a lighting control system was constructed to select the color and brightness of light that best suit the object being viewed. Cell images are captured by the instrument and the sharpness of each image is determined using Gaussian and Laplacian filters. Next, cubic spline interpolation and peak detection algorithms are applied to automatically find the most vivid points among multiple images of a single object. A cancer cell imaging experiment using propidium iodide staining confirmed that a sharp multipoint image can be obtained using this microscope. The proposed system is expected to save time and effort required to extract suitable cell images and increase the convenience of cell analysis.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.643-645
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• 2008

Stainless steel 304 and 316 plates were deposited with the multi-layered coatings of titanium film (0.1um) and gold film (1-2um) by an electron beam evaporation method. The XRD patterns of the stainless steel plates modified with the multi-layered coatings showed the crystalline phases of the external gold film and the stainless steel substrate. Surface microstructural morphologies of the stainless steel bipolar plates modified with multi-layered coatings were observed by AFM and FE-SEM images. The external gold films formed on the stainless steel plates showed microstructure of grains of about 100nm diameter. The grain size of the external surface of the stainless steel plates increased with the gold film thickness. The electrical resistance and water contact angle of the stainless steel bipolar plates covered with multi-layered coatings were examined with the thickness of the external gold film.

• Genomics & Informatics
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• v.16 no.4
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• pp.17.1-17.6
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• 2018

Tumor heterogeneity, the cellular mosaic of multiple lineages arising from the process of clonal evolution, has continued to thwart multi-omics analyses using traditional bulk sequencing methods. The application of single-cell sequencing, in concert with existing genomics methods, has enabled high-resolution interrogation of the genome, transcriptome, epigenome, and proteome. Applied to cancers, these single-cell multi-omics methods bypass previous limitations on data resolution and have enabled a more nuanced understanding of the evolutionary dynamics of tumor progression, immune evasion, metastasis, and treatment resistance. This review details the growing number of novel single-cell multi-omics methods applied to tumors and further discusses recent discoveries emerging from these approaches, especially in regard to immunotherapy.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.456-461
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• 2003

A fuel cell is an electrochemical device in which the energy of a chemical reaction is converted directly into electricity. By combining hydrogen fuel with oxygen from air, electricity is formed, without combustion of any form. Water and heat are the only by-products when hydrogen is used as the fuel source. Fuel cell stack consists of multi-layered unit cells. A unit cell consists of MEA and bipolar plates. The end plate of fuel cell stack should give a uniform distributed pressure to multi unit cell layers so as to reduce the contact resistance and to prevent the leakage of reactant gases and the damage of multi layer components. The current end plate is redundantly large and heavy. It makes the power per unit volume reduced. Topology optimization of end plate is conducted for mass reduction and enhancement of bending rigidity. The evaluation of the current design and the recommendation for the future design is remarked.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.11
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• pp.496-500
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• 2003

A low-cost, large area, random, maskless texturing scheme independent of crystal orientation is expected to significantly impact terrestrial photovoltaic technology. We investigated silicon surface microstructures formed by reactive ion etching (RIE) in Multi-Hollow cathode system. Desirable texturing effect has been achieved when radio-frequency (rf) power of about 20 Watt per one hollow cathode glow is applied for our RF Multi-Hollow cathode system. The black silicon etched surface shows almost zero reflectance in the visible region as well as in near IR region. The etched silicon surface is covered by columnar microstructures with diameters from 50 to 100 nm and depth of about 500 nm. We have successfully achieved 11.7% efficiency of mono-crystalline silicon solar cell and 10.2% multi-crystalline silicon solar cell.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.141-147
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• 2007

In this paper, we define the multi-states exponential cell resident time mobility model for describing the mobility characteristics of mobile user and analyzed the total cost of the hybrid method using multi-states cell resident time. Generally, the mobile user has three states for its movement, such as staying, walking and driving. This multi-states cell resident time based hybrid method reflects the movement characteristics of mobile user and adapts the location update period according to the states of mobility speed. As a results of the performance analysis, we can get the optimum parameters of the hybrid method for multi-states based mobile users.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.8A
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• pp.706-711
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• 2012

Multi-level cell NAND flash is a flash memory technology using multiple levels per cell to allow more bits to be stored. Currently, most multi-level cell NAND stores 2 bits of information per cell. This reduces the amount of margin separating the states and results in the possibility of more errors. The most error cause is coupling noise. Thus, in this paper, we studied coupling noise cancellation scheme for reduction memory on the 16-level cell NAND flash memory channel. Also, we compared the performance threshold detection and proposed scheme.