• 한국생산제조학회지
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• 제21권5호
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• pp.733-740
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• 2012

This paper studies with structural and vibration analysis to evaluate the structural safety according to the types of steering wheels. This study models are two, three and four spoke types. As the number of spokes increases, the maximum equivalent stress becomes smaller but the maximum total deformation becomes a little higher. The natural frequency at three models are shown from 180 to 230Hz as the maximum deformation. The frequency responses as maximum amplitude displacement are happened at 200Hz, 500Hz and 500Hz respectively. In this study, the steering wheel with three spoke type is shown to become suitable at durability and production.

• 제어로봇시스템학회논문지
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• 제13권2호
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• pp.173-178
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• 2007

This paper is to establish an appropriate model for predicting the temperature decreases in the batch transferred from the refining process to the caster in steel-making companies. Mathematical modeling of the temperature decreases between the processes is difficult, since the reaction mechanism by which the temperature changes in a molten steel batch is dynamic, uncertain and complex. Three soft computing techniques are examined using the same data, namely the multiple regression, fuzzy regression, and neural net (NN) models. To compare the accuracy of these three models, a limited number of input variables are selected from those variables significantly affecting the temperature decrease. The results show that the difference in accuracy between the three models is not statistically significant. Nonetheless, the NN model is recommended because of its adaptive ability and robustness. The method presented in this paper allows the temperature decrease to be predicted without requiring any precise metallurgical knowledge.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2008년도 제39차 학술발표회
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• pp.73-74
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• 2008

Three primary color super hydrophobic dyes were used to dye unmodified polypropylene fiber for various practical color. The color values of the dyed fibers were displayed on CIE 1931 Yxy chromaticity diagram. It was found that they showed various colors between three primary colors on the unmodified polypropylene fiber.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2001년도 종합학술발표회 논문집 Vol.11 No.1
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• pp.140-144
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• 2001

This paper describes to extend the MLFMA(Multi-Level Fast Multipole Algorithm) for three-dimensional capacitance computation in the case of conductors embedded in an arbitrary dielectric medium. The triangular meshes are used and refined in the area which has heavy charge density. This technique is applied to the capacitance extraction of three-dimensional structures with multiple dielectrics. The results show good convergence with the comparable accuracy, and this adaptive technique coupled with MLFMA is useful to reduce computing time and the number of elements without additional computational efforts in large three dimensional problems.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제4권4호
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• pp.215-220
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• 2000

This study on the incineration ash and sintering pellet from sewage sludge was carried out to evaluate the possibility of recycling in sewage sludge disposal. The samples used in this experiment were raw sewage sludge, its incineration ash, and sintering pellet. The characteristics of the three sample types were identified using X-ray diffraction(XRD), X-ray fluorescence(XRF), atomic absorption spectroscopy(AAS), and inductively coupled plasma spectroscopy(ICP). The chemical compositions of all three sample types were similar in their clay component, however, the sewage sludge had a high content of organic materials. From an analysis of the mineral content of the three sample types, the conversion of their compositions was found to be relative to temperature. Accordingly, incineration ash and sintering pellet both have potential for use as a functional construction material.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.384-386
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• 2006

본 논문에서는 AC Plasma display panel(AC-PDP) 구동을 위한 Six-switch를 적용한 Three-level PDP Sustain 회로를 제안한다. 제안 회로는 기존 회로의 Sustain 스위치와 Clamp 다이오드의 내압이 절반이 되어 특성이 우수한 반도체 소자의 채택이 가능하며, 환류 전류가 저감되어 높은 전력 효율을 가지는 장점을 가지므로 AC-PDP 구동 회로 설계에 매우 적합하다. 본 논문에서는 기존 회로와 제안 회로의 전도 손실 계산 및 시뮬레이션과 실험 결과를 보였다.

• Ocean and Polar Research
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• 제27권2호
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• pp.215-219
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• 2005

We isolated and identified three protease-producing bacteria that had inhabited the region around the Korean Arctic Research Station Dasan located at Ny-Alesund, Svalbard, Norway $(79^{\circ}N,\;12^{\circ}E)$. Biofilms were collected from the surface of a floating pier and from dead brown algae in a tide pool near the seashore. The biofilm samples were transported to the Korea Polar Research Institute (KOPRI) under frozen conditions, diluted in sterilized seawater, and cultured on Zobell agar plates with 1% skim milk at $10^{\circ}C$. Three clear zone forming colonies were selected as protease-producing bacteria. Phylogenetic analysis based on 16S rDNA sequences showed that these three stains shared high sequence similarities with Pseudoalteromonas elyakovii, Exiguobacterium oxidotofewm Pseudomonas jessenii, respectively. We expect these Arctic bacteria may be used to develop new varieties of protease that are active at low temperatures.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 총회 및 춘계학술발표회
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• pp.405-407
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• 2005

To evaluate the main hydrogeochemical characteristics, river waters are investigated using element리 and isotopic compositions in South Korea. In this area, the chemical compositions are mostly classified into three groups; $Ca^{2+}-{HCO_3}^-$ type, $Ca^{2+}-Cl^{-}-{NO_3}^-$ type and $Ca^{2+}-{HCO_3}^{-}-Cl^{-}-{NO_3}^-$ type. These types are affected by two major factors: water-rock interaction and anthropogenic inputs such as sewage and fertilizers. Based on the values of ${\delta}^{18}O$ and ${\delta}D$, most of waters are originated from precipitation except two samples contaminated. The lithology and geography of basins mainly control the water chemistry. Elemental and isotopic compositions show that water chemistry are mainly controlled by three end members, especially by carbonate dissolution, and suggest that anthropogenic input affect the water chemistry. Also, three weathering sources are identified: silicates, dolomite and limestone.

• 대한지구과학교육학회지
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• 제3권3호
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• pp.248-256
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• 2010

This study analyzed National Assessment of Educational Achievement items surveying to sixth-year student in elementary school utilizing three dimentional scientific assessment framework. Study's findings are as following. Science contents territory of national level study achievements estimation were set a problem energy, substance, life, earth relatively evenly. Action territory was set a problem most 'Comprehension' territory. In the case of science situation area, 'Purity scientific situation' among 5 category appeared the most.

• 한국시스템다이내믹스연구
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• 제11권3호
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• pp.61-86
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• 2010

This research analyzed on the future energy society of Korea in 2030 using system thinking approach. Key uncertainty factors determining the future energy society were analyzed in a multi disciplinary view point such as politics, economy, society, ecology and technology. Three causal loop diagrams for the future energy system in Korea and related policy leverages were shown as well. 'Global economic trends', 'change of industrial structure' and 'energy price' were identified as key uncertainty factors determining the Korean energy future. Three causal loop diagrams named as 'rate of energy self－sufficiency and alternative energy production', 'economic activity and energy demand' and 'Excavation of new growth engines' were developed. We integrated those causal loop diagrams into one to understand the entire energy system of the future, proposed three strategic scenarios(optimistic, pessimistic and most likely) and discussed implications and limits of this research.