• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.4
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• pp.354-363
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• 2012

Now there are a lot of expired satellites or space debris around the earth orbit and they threaten the operating satellites and manned space missions. KOMPSAT-2 that scheduled to operate the mission by July, 2013 also has to consider the space debris. This paper introduces the '25 years rules' that must be re-entered within 25 years after the space mission for LEO satellites and describes the removal trajectory design that satisfies the '25 years rules' and minimizes fuel consumption. And this paper suggests monte-carlo simulation for risk analysis that causes the approaching object to the removal trajectory. The result shows that the collision probability of worst case presents 6.0741E-07 and it need to more analysis about precise satellite safety during removal maneuver because there is no information about the object size that approaching to the satellites.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.396-399
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• 2002

A roughing process is the one of most important shoe manufacturing processes. Especially, it is indispensable to manufacture the leather shoes such as dress shoes, safety shoes, golf shoes, etc. The roughing process relies greatly on the operator's skill and experience. Therefore, the automation of roughing process is necessary to establish the improvement of productivity. We are trying to develop the Automatic Roughing Machine controlled by NC. As pre-study to do this, we need to measure the roughing path for NC, because there is no study on this pan and no reference about this. In this study, we proposed the 3-Dimensional Scanner System to measure the roughing path with new concept. The developed 3-D scanner System generates the roughing path using the 3 images obtained from 3 CCD cameras. The experimental results show that the proposed system can measure accurately the roughing path.

• Korean Journal of Plant Resources
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• v.27 no.5
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• pp.439-446
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• 2014

This study describes a preliminary evaluation of the anti-inflammatory activity of Castanopsis cuspidata extracts. C. cuspidata was extracted using 80% ethanol and then fractionated sequentially with n-hexane, dichloromethane, ethylacetate, and butanol. To screen for anti-inflammatory agents effectively, we first examined the inhibitory effect of the C. cuspidata extracts on the production of pro-inflammatory factors and cytokines stimulated with lipopolysaccharide. In addition, we examined the inhibitory effect of C. cuspidata extracts on pro-inflammatory mediators (NO, iNOS, COX-2) in murine macrophage RAW 264.7 cells. The amounts of protein levels were determined by immunoblotting. Of the sequential solvent fractions of C. cuspidata, the n-hexane, dichloromethane and ethylacetate fractions inhibited the mRNA expression of pro-inflammatory cytokines (IL-$1{\beta}$ and IL-6), production of NO, and the protein level of iNOS and COX-2. These results suggest that C. cuspidata may have significant effects on inflammatory factors and may be provided as a possible anti-inflammatory therapeutic plant.

• Food Science and Preservation
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• v.31 no.3
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• pp.462-473
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• 2024

The anti-inflammatory effect of beluga lentil extract (BLE) and its underlying mechanisms were investigated in lipopolysaccharide (LPS)-treated RAW 264.7 cells. Treatment with BLE significantly decreased nitric oxide (NO) production and protein and mRNA expressions of inducible NO synthase (iNOS) in LPS-treated RAW 264.7 cells. Down-regulation of this inflammatory gene expression was not associated with NF-κB/MAPK signaling pathways, and further mechanistic studies demonstrated that BLE decreased LPS-induced iNOS expression through upregulation of the nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated heme oxygenase-1 (HO-1) expression. These results suggest that beluga lentil represent a potential source of natural anti-inflammatory agents, and further studies will be necessary to determine its anti-inflammatory effects in vivo.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10B
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• pp.872-882
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• 2006

The Wireless Mesh Network uses a wireless communication technology with transmission rates similar to that of a cable, which is used as a backbone network. The topology structure is in a Mesh form which resembles an Ad-hoc network, however a metric is needed in order to set the channel and channel methods since the operation intentions and interior motions are different. This thesis proposes a metric(ETR : Expected Transmission Rate) that sets the channel with physical link performance and multi hop transmission capabilities. This metric will also be based on multi channel creation methods and Hop-by-hop routing techniques for an effective multi hop transmission with no loops.

• Proceedings of the Korea Contents Association Conference
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• 2019.05a
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• pp.445-446
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• 2019

빅데이터 시대의 도래로 다양한 NoSQL 데이터베이스 엔진이 활용되고 있다. NoSQL 데이터베이스 엔진 기반의 다양한 응용들이 수행될 때 스토리지의 성능을 평가하기 위한 스토리지 벤치마킹 툴이 요구된다. 본 논문에서는 NoSQL 데이터베이스를 이용한 스토리지 벤치마킹 시스템을 설계한다. 제안하는 스토리지 벤치마킹 시스템은 IO 추적기를 통해 스토리지의 성능을 측정하고, 웹 UI를 통해 사용자 정의 워크로드 생성, 벤치마킹 실행, 결과 확인을 수행할 수 있다.

• Microbiology and Biotechnology Letters
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• v.5 no.1
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• pp.36-45
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• 1977

A piscicidal substance was isolated from the culture medium of Streptomyces umbrosus by avicel column chromatography and avicel thin layer chromatography after extration with chroloform. Bluegreen fluorescence was emitted under UV irradiation. Factors which govern toxin production and nutrition requirement for high toxin titres were observed. Nutritional uptake for toxin production was not curresponded with that for cell growth. Alanine, valine, serine asparagine, arginine, histidine, urea and sodium nitrate as a carbon source and glucose, mannose, rhamnose, xylose, arabitol and starch as a carbon source were recognized as a favorable nutrient for high toxin production. Magnesium was essential factor whereas vitamins were not of effective. Most of toxin was formed simultaneously with cell growth in esponential phase. Maximal production was observed for six day culture at 3$0^{\circ}C$. Tissues of gill, kidney and pnacreas in Cyprinus carpio were denatured extreamly after treating with the substance. Atrophied nucleous, indented membrane and degradated cytoplasm with necrotic affectness were noted on each tissue. The chemical formula of the substance was designated as $C_{38}$ $H_{66}$ $NO_4$.

• Journal of Life Science
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• v.21 no.4
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• pp.534-541
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• 2011

Retinoic acid (RA), a metabolite of vitamin A, is known to regulate dedifferentiation of rabbit articular chondrocytes. The regulatory mechanism of dedifferentiation by RA is not yet understood. Thus, the effect of RA on the regulation of nitric oxide (NO)-induced dedifferentiation was investigated in rabbit articular chondrocytes. RA caused loss of the differentiated chondrocyte phenotype as demonstrated by inhibition of type II collagen expression and proteoglycan synthesis. RA also accelerated NO-induced dedifferentiation in rabbit articular chondrocytes as detected by expression of type II collagen and Sox-9 using Western blot analysis and production of sulfated proteoglycan using Alcain blue staining. Further, RA potentiated NO-induced activation of ERK. Inhibition of ERK with PD98059 (PD) recovered the expression of type II collagen and Sox-9 and production of sulfate proteoglycan in NO-induced dedifferentiated chondrocytes by RA treatment. Our findings suggest that RA accelerates NO-induced dedifferentiation of rabbit articular chondrocytes via the ERK pathway.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.4
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• pp.400-412
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• 2022

Hydrogen with high chemical reactivity and combustion efficiency, is expected to reduce greenhouse gas and CO emission. However, there is a problem of increase in NOx emission due to hydrogen combustion. MILD combustion technology has been proposed to resolve NOx emission. In this study, the characteristics of MILD combustion and NOx formation by flue gas recirculation (KV) in CH₄-H₂ mixture were analyzed and predicted using 0D premixed combustion model. The ignition delay time became shorter as the hydrogen co-firing rate increased, and longer as the recirculation rate increased. For NOx emission, EINO decreased as the KV increased, but EINO increased as the hydrogen co- firing rate increased. In particular, EINO was predicted to increase significiently above 80% hydrogen. Through the pathway analysis of NO formation, it was found that the influence of N₂O intermediate route and NNH route was enhanced for hydrogen co-firing.

• Clean Technology
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• v.27 no.4
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• pp.341-349
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• 2021

In combustion facilities, the nitrogen and sulfur in fossil fuels react with oxygen to generate air pollutants such as nitrogen oxides (NO_X) and sulfur oxides (SO_X), which are harmful to the human body and cause environmental pollution. There are regulations worldwide to reduce NO_X and SO_X, and various technologies are being applied to meet these regulations. There are commercialized methods to reduce NO_X and SO_X emissions such as selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR) and wet flue gas desulfurization (WFGD), but due to the disadvantages of these methods, many studies have been conducted to simultaneously remove NO_X and SO_X. However, even in the NO_X and SO_X simultaneous removal methods, there are problems with wastewater generation due to oxidants and absorbents, costs incurred due to the use of catalysts and electrolysis to activate specific oxidants, and the harmfulness of gas oxidants themselves. Therefore, in this research, microbubbles generated in a high-pressure disperser and reducing agents were used to reduce costs and facilitate wastewater treatment in order to compensate for the shortcomings of the NO_X, SO_X simultaneous treatment method. It was confirmed through image processing and ESR (electron spin resonance) analysis that the disperser generates real microbubbles. NO_X and SO_X removal tests according to temperature were also conducted using only microbubbles. In addition, the removal efficiencies of NO_X and SO_X are about 75% and 99% using a reducing agent and microbubbles to reduce wastewater. When a small amount of oxidizing agent was added to this microbubble system, both NO_X and SO_X removal rates achieved 99% or more. Based on these findings, it is expected that this suggested method will contribute to solving the cost and environmental problems associated with the wet oxidation removal method.