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Dryer Design for High Altitude Engine Test (고공 엔진시험을 위한 Dryer 개발)

  • Park, Berm-Joo;Kim, Tea-In
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.11a
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    • pp.419-423
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    • 2008
  • 엔진 성능의 시험에 있어서 작동유체인 압축공기의 물성중 수분은 매우 중요한 부분으로, 엔진의 작동과 성능에 영향을 미치는 대표적인 요인이다. 특히 고공환경 시험에서는 습도의 조건에 따라 성능의 차이가 커지므로 엔진의 정확한 성능과 운용성을 파악하는데 작동유체인 압축공기중에 포함된 수분의 조건은 대단히 중요하다. 압축상태인 작동유체의 수분 함유량을 고공의 조건과 같은 $-40^{\circ}C$ 이하의 이슬점(Dew Point) 상태로 제습 하기 위한 장치인 흡착식 Air Dryer의 개발을 위해 흡착과정 및 재생과정에 대한 이해와 흡착제의 흡착효율을 극대화하고, 재생비용을 최소화하여 에너지를 저감 할 수 있는 Air Dryer System에 대하여 기술한다.

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A Study on the Status Analysis and the Improvement Method for the Information Security of Middle and High School (중·고등학교 정보보호 현황 분석 및 개선 방안 연구)

  • Hwang, Berm-Sik;Shin, Seung-Jung;Ryu, Dae-Hyun
    • Proceedings of the Korea Information Processing Society Conference
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    • 2009.04a
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    • pp.1535-1538
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    • 2009
  • 1996년 7월 교육정보화촉진계획의 입안으로부터 시작한 교육정보화사업은 많은 긍정적인 성과를 거두고 있지만 전산망이 인터넷과 연결되면서 역기능도 점차 증가하고 있다. 전산망 관리자 및 보안전문가 없이 교사가 관리하는 학교 전산망의 경우 보안에 취약해 전산망의 정상적 운용 및 개인정보보호가 위협받고 있다. 본 연구에서는 학교전산망의 정보보안 취약점을 개선하기 위해 정보보호 현황 분석하여 개선방안을 모색해 보고자 한다.

Study on the Revegetation Methods for the Rehabilitation and Restoration of the Disturbed Slopes in Limestone Mines -Case study of Ibuki mine and Bukou mine in Japan- (석회석광산의 식생녹화방법에 관한 고찰 -일본 이부키광산과 부코우광산의 사례연구-)

  • Lee, Joon-Woo;Kim, Nam-Choon;Nam, Sang-Joon;Park, Chong-Min;Cha, Du-Song
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.6 no.6
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    • pp.72-85
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    • 2003
  • The purpose of this study is to establish the basis of the ecological restoration on the limestone mines in Korea, through the research of the revegetation measures of the disturbed slopes in Japanese limestone mines and the analysis of the case of Ibuki and Bukou limestone mines to realize the restoration works successfully. According to the number of mines to carry out the revegetation works increase every year, the revegetation area and amount of planting also go on increasing in Japan. In the small mines the environmental problem is not recognized seriously, but some mines have muchly invested in the revegetation of the damaged land by mines. Ibuki mine in Shiga-gen is practicing the four principles for the restoring of the revegetation in the disturbed slopes by mines. Firstly, the mean slope preserves $37^{\circ}$ in the last rock cut slopes. Secondly, the last rock cut slopes to rehabilitate are covered with the soil dressing 30cm high. Thirdly, the grasses in the mining area are digged up beforehand, and then they are reused to the revegetation works of rock cut slopes. Lastly, from the upper rock cut slopes the revegetation works begin, the process of the above are repeated, as the result, the restoring works will be completed. Upon the ground of these principles, the complex of the original vegetation and the native species seeding, that is, the revegetation technique of Ibuki have established. In the difficult area to revegetate, sodding works, heaping up vegetation-sack, seed-spraying, heaping up soil-sacks and planting works are adapted variously. Bukou mine in Saitama-gen try to maintain the revegetation, the screening and the stability of the enormous mining rock cut slope, and for these works, the activity of 'Chichibu Working Group of Rock Wall for Limestone Mines' contributes largely. The chief technique of the revegetation in Bukou mine is following; after the making the berm on the rock cut slopes, the soil dressing is filled in it, and the trees is planted for the screening of the rock cut slopes. They devide the rock cut slopes into four typical types, and choose the different ways to make the berm and fill the soil dressing in characteristic. Most of the planting trees are consist ofthe native species of Mt. Bukou through the stages of the nursery and transplantation. Not only the revegetation of the demaged land but also the breeding of the conservational plants also are their important business.

Analysis of Shoreline Change Using Multi-temporal Remote Sensed Data on Songjeong Beach, Busan (다중시기 원격탐사 자료를 이용한 부산 송정해수욕장의 해안선 변화 분석)

  • Jang, Dong-Ho;Kim, Jang-Soo;Baek, Seung-Gyun
    • Journal of The Geomorphological Association of Korea
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    • v.19 no.4
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    • pp.59-71
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    • 2012
  • This research was carried out to analyze long-term shoreline change on Busan Songjeong Beach using multi-temporal remote sensed data, GPS survey data and grain size analysis. As a result of multi-temporal satellite imagery analysis, the beach was stable status till early 2000s, but the erosion occurred over whole beach after the construction of shore protection road since 2000. In the result of DEM analysis, the elevation of beach reduced and the slope of berm increased after construction of shore protection road along the coast, this means the erosion environment was dominant on the beach. But the sedimentation was slightly stronger than the erosion in northern region of the beach, then the slope of berm was gentle. In the result of grain size analysis using in-situ samples, the coarsening-trend was found in southeastern region (Line E) of the beach, it is caused by strong wave energy from the outer sea. Consequently, major causes of the beach erosion in the study area were the interception of sand supply from a dune owing to shore protection road construction and scouring phenomenon by strong wave energy in southeastern region of the beach. If the topographic or artificial change will not occur in the future, the erosion in this area will continue. Therefore the prevention measures are required.

A Study on the Syllable Recognition Using Neural Network Predictive HMM

  • Kim, Soo-Hoon;Kim, Sang-Berm;Koh, Si-Young;Hur, Kang-In
    • The Journal of the Acoustical Society of Korea
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    • v.17 no.2E
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    • pp.26-30
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    • 1998
  • In this paper, we compose neural network predictive HMM(NNPHMM) to provide the dynamic feature of the speech pattern for the HMM. The NNPHMM is the hybrid network of neura network and the HMM. The NNPHMM trained to predict the future vector, varies each time. It is used instead of the mean vector in the HMM. In the experiment, we compared the recognition abilities of the one hundred Korean syllables according to the variation of hidden layer, state number and prediction orders of the NNPHMM. The hidden layer of NNPHMM increased from 10 dimensions to 30 dimensions, the state number increased from 4 to 6 and the prediction orders increased from 10 dimensions to 30 dimension, the state number increased from 4 to 6 and the prediction orders increased from the second oder to the fourth order. The NNPHMM in the experiment is composed of multi-layer perceptron with one hidden layer and CMHMM. As a result of the experiment, the case of prediction order is the second, the average recognition rate increased 3.5% when the state number is changed from 4 to 5. The case of prediction order is the third, the recognition rate increased 4.0%, and the case of prediction order is fourth, the recognition rate increased 3.2%. But the recognition rate decreased when the state number is changed from 5 to 6.

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Biological Manganese Removal in Water Treatment (정수처리에서 생물학적 망간처리)

  • Kim, Berm-Soo;Yoon, Jaekyung;Ann, Hyo-Won;Kim, Chung-Hwan
    • Journal of Korean Society of Water and Wastewater
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    • v.20 no.1
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    • pp.44-52
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    • 2006
  • Bio-filtration processes using honeycomb tubes (process 1) and aeration and manganese-sand filtration (process 2) were evaluated for the biological manganese removal efficiency. The concentration of manganese at effluent was stabilized after 20days operation in process 1. It was estimated the required time for attaching and growing microorganisms to honeycomb tubes. In long term of operation periods, manganese removal efficiency was dropped for the excessively attached biofilm and manganese dioxide to honeycomb tubes. It took several days for normal operation in process 2, after that manganese removal efficiency was increased to 98% and stabilized for 1.5 years. Microorganisms in process 1 and 2 were isolated and cultured to characterize manganese-oxidizing bacteria. Among the four types of colony, light brown colony was turned blue color by leuco crystal violet spot test. Stenotropomonas genus, known as manganese-oxidizing bacteria, was identified by 16S rDNA partial sequencing analysis which was isolated in process 1 and 2. For the biological treatment to remove manganese, these two considerations are important. One is to choose the proper media attaching manganese oxidant, another one is to define the cultural condition of isolated manganese-oxidizing bacteria.

Effect of Experimental Factors on Manganese Removal in Manganese Sand Filtration (망간모래여과공정에서 망간제거에 미치는 영향인자)

  • Kim, Berm-Soo;Yoon, Jaekyung;Ann, Hyo-Won;Kim, Chung-Hwan
    • Journal of Korean Society of Water and Wastewater
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    • v.20 no.1
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    • pp.86-93
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    • 2006
  • In the drinking water treatment, the aesthetic and color problem are caused by the manganese which is occurring and present in the surface, lake and ground water. The most common treatment processes for removing manganese are known for oxidation followed by filtration. In this study, the manganese sand process was used for removing manganese with river bank filtrate as a source. In the manganese sand process, the residual chlorine and pH are important factors on the continuous manganese oxidation. In addition, space velocity (SV) and alum dosage are play a role of manganese removal. Even though manganese removal increased with increasing chlorine concentration, the control of residual chlorine is actually difficult in this process As the results of tests, the residual chlorine concentration as well as manganese removal were effectively achieved at pH 7.5. The optimum attached manganese concentration on manganese sand was confirmed to 0.3mg/L by the experimental result of a typical sand converting to manganese sand.

Jinan red ginseng extract inhibits triglyceride synthesis via the regulation of LXR-SCD expression in hepatoma cells

  • Hwang, Seung-mi;Park, Chung-berm
    • Korean Journal of Food Science and Technology
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    • v.51 no.6
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    • pp.558-564
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    • 2019
  • Hypertriglyceridemia is one of the metabolic syndrome that is often observed as a result of lipid abnormalities. It is associated with other lipids, metabolic disorders, cardiovascular disease and liver disease. Korean red ginseng is known to affect obesity, dyslipidemia, liver disease and liver function, but the mechanism of its effect is not clear. This study examined the beneficial effects of hypertriglyceridemia and the mechanism of action of Jinan red ginseng extract (JRG) in hepatoma cells. To measure the levels of triglyceride accumulation, we studied the expression of proteins and mRNAs related to lipidogenesis in hepatoma cells (Huh7 and HepG2). JRG decreases the lipidogenic markers, peroxisome proliferator-activated receptor γ (PPARγ), CCAAT-enhancer-binding proteins α (C/EBPα) and C/EBPβ which are major regulators of triglyceride synthesis in hepatoma cells. We also found that JRG reduced sterol regulatory element binding proteins 1c (SREBP-1c), C/EBPα and C/EBPβ by regulating liver X receptor (LXR) and stearoyl CoA desaturase (SCD) expressions. In addition, the first-limited step of synthesis triglyceride (TG), glycerol-3-phosphate (G3P) is decreased by JRG. These results suggest that the anti-hypertriglyceride effect of JRG in hepatoma cells could be accompanied with the inhibition of lipidogenic transcription factors by regulating LXR and SCD expression.

Surface Roughness and Sintering Characteristics of Fe-8 wt%Ni Component Fabricated by PIM (Fe-8 wt%Ni 나노합금분말 사출성형체의 소결특성 및 표면조도)

  • Cha, Berm-Ha;Lee, Jai-Sung
    • Journal of Powder Materials
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    • v.16 no.5
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    • pp.342-350
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    • 2009
  • Development of nanoparticulate materials technology is essential to processing of highly functional nanoparticulate materials and components with small and complex shape. In this paper, the effect of particle size on surface roughness and shrinkage of sintered Fe-8 wt%Ni nanopowder components fabricated by PIM were investigated. The Fe-8 wt%Ni nanopowder was prepared by hydrogen reduction of ball-milled Fe$_2$O$_3$-NiO powder. Feedstock of nanopowder prepared with the wet-milled powder was injection molded into double gear shaped part at 120$^{\circ}C$. After sintering, the sintered part showed near full densified microstructure having apparently no porosity (98%T.D.). Surface roughness of sintered bulk using nanopowder was less than 815 nm and it was about seven times lower than 7 $\mu$m that is typically obtainable from a sintered part produced from PIM.