• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.771-776
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• 2004

치수사업에서 실시하는 경제성분석은 계획하고 있는 사업의 사회적 후생의 극대화 측면에서 경제적 타당성을 분석 평가하는 것으로서 일반적으로 편익${\cdot}$비용분석이 사용되고 있다. 이러한 경제성분석시의 문제점으로 직접편익뿐 아니라 간접편익 및 비계량편익에 해당하는 사업의 효과도 편익부분의 계산에 포함할 수 있는 방법이 필요한 실정이다. 이에 따라 본 연구에서는 홍수에 의한 교통두절로 인한 피해를 간접편익으로 고려하여 오산천지역에 적용해 보았다. 교통두절피해 편익의 항목으로서 주로 차량운행비용 절감과 통행시간비용 절감의 두 항목을 고려하였으며, 이 두 항목에 내한 결과에서 홍수지체시간당(단위 1일당) 적지 않은 편익이 발생하는 것으로 나타났다. 본 연구를 통해 일반적인 치수사업 경제성분석에서 이뤄지지 않았던 교통두절에 의한 피해항목을 간접편익으로 고려함으로써 홍수로 인한 교통두절피해를 정량적으로 계량할 수 있었으며, 실질적으로 편익에 영향이 가장 큰 편익가치(재화가치, 시간가치)에 대한 연구가 계속적으로 수반된다면 이후의 다른 치수사업 경제성분석시에 효과적인 분석이 이뤄질 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.713-713
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• 2012

그동안 사회적 여러 갈등의 갈등 조정을 위한 연구나 기술들은 주로 갈등발생원인들 중 법/제도적이나 정책추진 방법론 등 한 두 가지측면을 고려하여 평면적 분석을 시도하는 것이 대부분이고 특정지역 및 사례에 제한적으로 적용되는 것이 일반적이었다. 이와 같은 갈등 조정의 한계를 극복하기 위해 최근에는 이해당사자의 참여를 유도하고 공학적으로 접근하여 여러 대안 및 시나리오에 대해 모색할 수 있는 공영시각모형이 소개되면서 많은 정책결정과 수자원관리, 수질관리 분야 등에 널리 활용되고 있다. 하지만 객체지향을 내세우고 있는 공영시각모형은 신속한 모의 및 쉽게 모형을 다룰 수가 있다는 장점이 있으나, 공간적인 분석 및 표현은 불가능하다는 단점을 가지고 있다. 이에 본 연구에서는 ArcGIS를 기반으로 HEC-RAS와 연계하여 대상지역의 선 면적 개념의 치수적인 문제점을 도출시켜 이해당사자들에게 인식 및 이해시킬 수 있도록 하였으며, 댐 규모나 다른 대안이 수립되는 경우 이에 따른 수위저감효과와 홍수범람모의 및 홍수피해액 등을 제시할 수 있도록 개발하였다. 모형의 정확성, 신속성 및 다른 지역에서의 적용성 등을 확인하기 위하여 한탄강댐 갈등사례가 있었던 임진강 유역에 적용하여 모의운영 하였다. 그 결과 가상의 여러 대안에 의한 각 결과를 잘 제시하고 있었으며, 댐 건설 갈등현안 중 치수부문에 적용되어 갈등 조정에 기여할 수 있을 것이라고 판단된다.

• Journal of the Korean Wood Science and Technology
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• v.30 no.1
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• pp.40-47
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• 2002

This study was carried out to investigate the dimensional stability of three softwoods (Pinus densiflora S. et Z., Pinus koraiensis S. et Z., Larix kaempferi C_ARR.) and two hardwoods(Quercus mongolica F., Quercus variabilis B_L.) treated with polyethylene glycol(PEG). Existence of PEG in wood was examined by an X-ray diffraction method. Shrinkage of the sample woods decreased with increasing concentration of PEG. The dimensional stability of five species had improved highly in thirty percent solutions of PEG with molecular weight 1000~4000, and the dimension of PEG-treated softwoods was more stable than that of PEG-treated hardwoods. Weight gain and bulking effect of the woods treated with PEG increased with increasing concentration of PEG. X-ray diffractograms of Pinus koraiensis wood treated with PEG showed two peaks derived from PEG crystal at 2𝜃 = 19° and 2𝜃 = 23°. However, the diffractograms of Quercus mongolica wood did not present any peaks caused by PEG crystal. From the result of X-ray diffraction, it was revealed that the content of PEG in Pinus koraiensis wood was higher than that in Quercus mongolica wood.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.2
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• pp.146-158
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• 2002

The purpose of this study was to investigate the effects of Nd:YAG laser on mechanically exposed pulp of dog by the observation of pulpal inflammatory change and heal process including dentinal bridge, structural changes of fibroblasts of thr remaining vital pulp tissue. In experimental group 1, the exposed pulps were irradiated with Nd:YAG laser(3W, 30Hz, 0.2sec) for $2{\sim}3$ second followed by capped with aluminium tin foil. In group 2 and group 3, the exposed pulps were irradiated with Nd:YAG laser via contact(Group 2) and non-contact(Group 3) methods followed by capped with calciumhydroxide paste. The animal were sacrificed at the intervals of 3, 7, 14 and 30days for histologic evaluation. The results were as follows : 1. The dentinal bridges were formwd more fast and broadly in the experimental group 1 and 2 than other groups, but there were no histologic differences in the degree of their formation among control group, experimental group 1. 2. Odontoblastic activities at amputated pulp was increased in the experimental group 2, 3 than other group but there no histologic difference in the odontblastic activitiy among control group, experimental group 1. 3. The infalmmation was severe at the postoperative 1 week of all groups, but its condition subsideed with time elapsed. At the postoperative 3, 7 days, its condition in experimental group 2, 3 were less severe than in the group 1. 4. There were no histologic differences between the experimental group 2 and 3 according to the degree of dentin bridge formation.

• 전기의세계
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• v.21 no.2
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• pp.41-46
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• 1972

가공송전선의 전기적특성은 비교적 간단한 이론공식에 의하여 정확한 치수를 구할수 있으나, 지중선의 그것은 그렇지 않다. 지중선의 전기특성은 도체 상호간 근접효과, 절연체의 유도손, pipe내의 활유손, 그리고 토양의 방열효과등이 그 영향을 미치므로 그 이론공식이 대단히 복잡하다. 본문에서는 전호에 이어 우리나라에서 시초로 건설될 pipe type cable의 허용전류의 계산방법의 미완부분을 계속해서 소개하고져 한다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.11 s.254
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• pp.1392-1400
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• 2006

Since the monolithic ceramic substrate was in introduced for automotive catalytic converters, the durability of the substrate has been a continuing requirement to reduce the emission, gas of vehicle. The substrate can occupy a volume as small as 82 $cm^3$ and as large as 8200 $cm^3$ to provide the required substrate for catalytic activity. The long-term durability varies with the size of the substrate from manufacture's point of view. Therefore this study presents that the response surface model using central composite design can explain size effect on the modulus of rupture in a cordierite ceramic monolithic substrate.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.534-538
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• 2008

최근 여름철 기상이변과 게릴라성 집중호우로 인해 대도시 유역의 첨두홍수량은 급격히 증가하고 있으나, 대도시 지역은 비도심 지역에 비해 하천 확폭이나 제방 증고에 많은 제약이 있다. 이에 대한 도심지역의 홍수 예방대책으로 유역을 전환시키는 방수로는 하천통수능력을 초과하는 홍수량을 유역상류부에서 호수나 바다로 방류할 수 있어 하류지역 홍수부하량을 감소시켜 침수피해를 막을 수 있는 매우 효과적인 방안이라고 할 수 있다. 본 연구에서는 현재 사업 진행중인 굴포천방수로를 통한 굴포천 유역의 치수효과를 수치해석 및 실제 홍수처리 사례를 통해 분석하고자 한다.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.583-589
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• 2004

One of noticeable features in the cross flow fan is that a working fluid passes through impeller blade twice without distinction between the inlet and exit angles. Also, it does produce higher circumferential velocity than other types of blade at the same flow rate in accordance with the application of the forward curved shape. However, a design theory for the cross-flow fan has not yet been formed owing to an eccentric vortex, which is the remarkable characteristics, occurred in a cross-flow fan. Furthermore, the eccentric vortex, which is difficult to control of the size and position, is the important cause of performance decrease. In this study, experiments are carried out to estimate the similarity of the cross-flow fan with various scales and rotational velocity changes. Pressure coefficients to flow coefficients with various scales of the cross-flow fan are plotted to research the application of the general similarity law of the turbomachinery in the cross-flow fan with Archimedes spital, which is the important factor haying an effect on it.

• Restorative Dentistry and Endodontics
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• v.30 no.3
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• pp.193-203
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• 2005

The induction of the IL-8 and MCP-1 by the stimulation of Substance P and TNF-${\alpha}$ (IL-8 agonist) and the specificity for SP using Spantide (SP antagonist) in the dental pulp tissues was measured quantitatively. In addition, the secretion of the IL-8 in the human dental pulp tissue 36 hrs after the stimulation of SP was observed after the stimulation of SP qualitatively. According to this study the results were as follows: 1. There was the significant IL-8 induction at 36 h after SP (10$^{-4}$M) stimulation of the pulp tissue comparing with the unstimulated dental pulp tissues (p < 0.05) . IL-8 irnmunostaining was weakly detected along the periphery of the pulp tissue after Mock stimulation and IL-8 immunostaining was detected around the fibroblast in the pulp tissue 36h After SP (10$^{-4}$M) stimulation, 2. The secretion of MCP-1 from the dental pulp tissues comparing with Mock stimulation was induced at 36 hrs after TNF-$\alpha$ (40 ng/ml) stimulation, but no induction with SP(10$^{-4}$M) TNF-${\alpha}$ (40 ng/ml) did not induce the IL-8 secretion from the pulp tissue, weak IL-8 imrnunostaining was detected along the periphery of the pulp tissue 3. Spantide (10$^{-5}$M) inhibited IL-8 induction from the pulp tissues 36 h after SP (10$^{-4}$M) stimulation These results suggest that SP significantly induces IL-8 recruiting neutrophils in localized human dental pulp tissue MCP-1 appears to be less involved in the early establishment of pulpal inflammation in response to irritation such as mechanical insult of dentin. SP may have positive relation with the inflammation of the human dental pulp tissues.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.62-69
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• 2023

Re-damage is frequently occurring for various reasons, including material factors, external factors, and factors caused by poor construction in concrete cross-section restoration work, so it is necessary to identify the cause and improve it. Cement-based materials are the most commonly used maintenance materials for concrete structures, and in particular, additional cross-sectional restoration work may be carried out due to re-damage such as cracks and excitement due to dry contraction of the repair material. In this study, a basic study was conducted to identify the characteristics of concrete while diversifying the maximum dimensions and assembly rate of thick aggregates to examine the effects of using thick aggregates in repair materials. As a result, the slump of concrete increased as the maximum size of thick aggregates increased, and the amount of air content was measured 1.88 to 2.35 times higher in the mixing using aggregates with a maximum aggregate size of 5 mm or more compared to the mixing group with a maximum aggregate size of 10 mm or more. It was found that compressive strength was greatly affected by the performance rate of thick aggregates. The compressive strength was measured the highest in the mixture using thick aggregates with the highest performance rate of 20 mm, and the compressive strength of the mixture with the lowest performance rate was more than 45%. As a result of the dry shrinkage measurement, the dry shrinkage was the lowest as the performance rate of the thick aggregate increased according to the change in the maximum dimensions and assembly rate of the thick aggregate, and the lowest performance rate was the largest in the mix. Through this study, it was confirmed that adjusting the particle size by diversifying the maximum dimensions and assembly rate of thick aggregates used in concrete structure repair materials can improve strength and workability and reduce dry shrinkage.