• Journal of Korean Society of Steel Construction
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• v.18 no.6
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• pp.747-758
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• 2006

With the growth of economy, the esthetic values of bridges become significant points in the decision process of a type of new bridges. So, it is common that a long-span bridge or a multi-purpose bridge are selected as the type of new bridges. Also, the economic growth derives increase in traffic and then the increased traffic derives multi purpose bridges from the decision process of bridge types. In the multi-purpose bridges with private fund, the construction cost is simply alloted to several organizations according to the percentage of participation and usage. But the allotment of the maintenance cost is not simple. Because the loads and safety factors in design are different between the criterion of design of highway bridges and that of railway bridges. In this study, we verify the possible problems in case of allotment method of maintenance cost in foreign examples as well as domestic example. As one of the method of determination of allotment ratio in maintenance cost, the method based on the stress of structural analysis is presented and it can be an example in the similar problem later.

• Proceedings of the Turfgrass Society of Korea Conference
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• 2011.02a
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• pp.25-32
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• 2011

본 연구는 화력발전의 부산물로 발생하는 석탄바닥재가 골프장 사질 토양의 개량재로 사용 적합한지를 평가하기 위해 수행되었으며, 결과를 요약하면 다음과 같다. 1. 석탄바닥재의 화학성을 분석한 결과 총질소 0.34%, 가용성 인산 $52mgL^{-1}$, 치환성 칼륨 $51mgL^{-1}$ 뿐만 아니라 소량의 치환성 칼슘과 마그네슘을 함유하고 있어 식물생육에 이롭고, 유해중금속함량은 Cd, $Cr^{6+}$, Pb, Ni, As는 $1mgL^{-1}$ 이하, Cu 농도는 $1.25mgL^{-1}$ 검출되어 토양환경보전법의 토양오염우려기준 이하이므로 석탄바닥재 재활용으로 인한 토양오염 가능성은 매우 낮은 것으로 판단된다. 2. 모래 토양에 석탄바닥재를 부피비로 0~50% 비율로 혼합한 시료의 투수계수와 유효수분함량을 측정한 결과 석탄바닥재 혼합비율이 증가할수록 투수계수는 유의성 있게 감소하고 유효수분함량은 유의성 있게 증가해 석탄바닥재가 모래 토양의 낮은 수분보유력을 개선하는 효과가 있음을 확인하였다. 3. 모래 토양에 석탄바닥재를 부피비로 0~50% 비율로 혼합한 시료를 잔디식재층으로 조성한 라이시미터에 잔디종자 파종 후 약 4개월 뒤 잔디밀도가 완전히 형성된 후에 시비 후 3일 간격으로 채취한 용탈수를 분석한 결과 1일과 4일 후에 채취한 초기 용탈수에서는 석탄바닥재 혼합비율이 높을수록 $NO_3-N$, $NH_4-N$ 및 K함량이 유의성 있게 감소했으며, 대조구에 비해 석탄바닥재 혼합비율이 높은 처리구일수록 $NO_3-N$, $NH_4-N$ 및 K함량이 용탈수 채취기간 동안 지속적으로 용탈되었다. 이 결과로 석탄바닥재가 모래 토양의 낮은 양분 보유력을 개선하는데 효과적이고 석탄바닥재처리가 대조구에 비해 오랫동안 식물 생육에 필요한 양분을 공급하는 효과가 있음을 확인하였다. 4. 골프장 그린상구조와 동일한 시험포장을 만들고 모래 토양에 석탄바닥재 10%와 20% 그리고 피트, 액시스, 이소라이트를 부피비로 10% 비율로 혼합한 시료를 잔디식재층으로 조성하고 크리핑 벤트그래스(Agrostis paulstris Huds), Penn A-4 $10gm^{-2}$을 파종한 후에 처리구별로 잔디 품질을 평가하기 위해 잔디 밀도, 뿌리길이, 색상 및 시각적 품질을 조사한 결과 석탄바닥재 처리구는 기존에 사용하는 개량제인 피트, 액시스, 이소라이트 처리구와 동등한 잔디생육 촉진 효과가 있는 것으로 조사되었다. 5. 결론적으로 석탄바닥재는 골프장 토양의 물리적 특성과 화학적 특성을 개선하고 잔디생육에 필요한 양분을 공급하는데 효과적인 토양개량재라고 할 수 있다.

• Korea Trade Review
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• v.41 no.1
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• pp.41-66
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• 2016

This paper analyzes the firms value and the business performance before and after Chinese firms got listed in the U.S. First of all, it was separated into term before U.S listed and after listed, and looked whether there was any change in the Tobin'Q. After listed, as time went on Tobin'Q decreased more. In terms of net sales growth rate, it dropped significantly after U.S IPO. Operating profits and net profits rate increased more after being listed in large corporation, but in small corporation cases, it produced an opposite effect on debt ratio and net interest cost. Interest burden continued to fall after being listed in small corporation, and it couldn't find the investment profitability, nor could it utilize ROE, ROI variable. ROE, ROI continued to fall after being listed, but current ratio and quick ratio increased significantly in small corporation. From this results, we can infer that the financial liquidity showed signs of improvement after being listed.

• Culinary science and hospitality research
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• v.10 no.3
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• pp.135-154
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• 2004

This study surveyed ancestral service preparation and sacrificial consciousness of housewives living in Pusan and Yeosu area. Statistical analysis of chi-square test was carried out by using SAS program. The results are summarized as follows. l. In major general characteristics of subjects, the forties(35.56%), Buddhism (57.79%), high school education(52.54%), a couple with children(63.45%) were the most abundant. 2. The time of sacrificial rites in both areas was usually hold from 23:00 to 01:00 (47.16%). The housewives having a job hold earlier the service than the full-time housewives(p<0.05). 3. The range of ancestor-memorial rites was usually up to 3rd generation(34.47%). The leader of sacrificial ceremony was mainly the eldest grandson by the eldest son (78.28%) in the old subjects and a person of wealth in the young subjects(p<0.05). 4. There were more positive answers for the necessity of a sacrificial ceremony (57.32%). Older than 50 years of subjects thought the sacrificial rites should be held(70.77%), while as the age of subjects was younger, they realized less necessity for that(p<0.05). Sacrificial consciousness was higher in Buddhists than the other religionists(p<0.0001). The sacrificial rites was thought to be needed for their harmonious family(50.43%). Younger subjects thought that it is necessary to succeed that as the tradition, while older housewives thought that it would contribute toward peace in their family(p<0.05). Buddhists and Christians answered that it was good for harmonious family, and Catholics and the others for tradition(p<0.01). Their consideration of sacrificial rites in the future was higher in keeping the traditional practice (37.04%) and Buddhists took higher these consideration(43.17%). Considering the sacrificial consciousness, there were statistical differences among the religionists (p<0.0001). The eldest daughter-in-raw had a different opinion about the following up the method of sacrificial ceremony from second eldest daughter-in-raw and the next one(p<0.05). The housewives in Pusan were showing more the affirmative attitudes to keep the traditional practice than those in Yeosu.

• The Korean Journal of Financial Studies
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• v.6 no.1
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• pp.117-140
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• 2000

본 연구는 그간 실무계와 학계에서 주목을 받고 있는 EVA 모형과 기업가치모형간의 상호 관계를 보여주고 실증적으로 예측치 경상이익과 순이익을 이용하여 EVA와 기업가치를 측정하고 이러한 예측가치와 실제가치와의 관계를 살펴보았다. 1990년부터 5년간 모두 535 기업을 대상으로 분석한 결과 강효석과 남명수 (1998)의 연구와 같이 모든 연도에 부의 EVA를 보여 주고 있으며 1년 예측치보다 2년 예측치를 기초로 산정한 기업가치가 실제가치에 근접하였다. 각 연도 별로 보면 예상경상이익을 사용한 경우 70%부터 94%까지의 높은 설명력을 보여주며, 5년 누계는 83%의 설명력을 나타냈다. 경상이익 대신 순이익을 사용한 경우도 유사한 결과를 보여주고 있다. 끝으로 가치평가오차를 원천별로 그리고 유형별로 분석하였는데 기업가치 예측오차 중 경제전반이 설명하는 부분은 10%정도, 산업은 $13{\sim}15%$, 그리고 개별기업이 $75{\sim}77%$를 차지하고 있어 개별기업의 중요도가 미국에 비하여 낮은 수준을 보여주고 있다. 유형별로도 편의비율이나 회귀비율이 $5{\sim}8%$수준인데 비하여 무작위 비율이 86%수준을 보여 주고있다.

• Proceedings of the Korean Statistical Society Conference
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• 2003.10a
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• pp.319-324
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• 2003

본 논문에서는 matched-pair design에서의 두 처리간 동등성/ 비열등성 검정에 대해 고려하였다. 기존에 비율차이나 risk ratio관점에서 동등성/비열등성 검정을 시행한 것과는 달리, 본 논문에서는 odds ratio에 기초하여 두 가지 검정통계량을 유도하였다. (1) constrained maximum likelihood estimator(mle)를 이용한 fieller type 통계량 (2) 제약없이 구한 mle를 사용한 wald-type 통계량). 비율 차이나 risk ratio에 기초한 기존의 통계적 방법들(비율차이에 근거한 (3) score-type 통계량과 (4) wald-type 통계량, risk ratio에 기초한 (5) fieller-type 통계량과 (6) wald-type 통계량)과 본 논문에서 제시한 두가지 통계량의 성능을 비교하기 위해 모의실험을 시행하였다. 모의실험 결과, 본 논문에서 제안한 constrained mle를 사용한 fieller type 통계량은 empirical type I error 측면에서 매우 만족스러운 결과를 보이고 있으며, 특히 비대각 셀의 확률이 작아질 경우에도 안정적인 성능을 보여준다.

• Tunnel and Underground Space
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• v.25 no.5
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• pp.423-434
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• 2015

Scaled model tests were performed to investigate the influence of pillar width, rock strength and isotropy/anisotropy on the stability of twin tunnels. Test models had respectively different pillar widths, uniaxial compressive strengths of modelling materials and model types, where both the deformation behaviors around tunnels and the biaxial pressure data at a time of pillar cracking were analysed. The cracking pressures of the higher strength models were higher than the lower strength models, whereas the percentage of cracking pressure to uniaxial compressive strength of modelling materials showed an opposite tendency. The cracking pressures of the shallower pillar width models were lower than the thicker models, moreover the percentage of that showed a same tendency. It has been found that the pillar width was one of the main factors influencing on the stability of twin tunnels. Model types such as isotropy/anisotropy also influenced on the stability of twin tunnels. The anisotropic models showed lower values of both cracking pressures and the percentage of that than the isotropic models, where the pillar cracks of anisotropic models were generated with regard to the pre-existing joint planes.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.66-71
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• 2012

We deal with a problem to determine experimentally as well as theoretically permeability of incompressible viscous flow through packed bed of bidisperse hard spheres in size. For the size ratios of large to small spheres ${\lambda}$=1.25 and 2, we set up bidisperse packing and measured porosity and permeability at various volumetric ratios of small to large spheres ${\gamma}$. Bidisperse packing shows lower porosity and permeability than monodisperse packing does. Variation of porosity as a function of ${\gamma}$ does not match with that of permeability. A theoretical expression for predicting permeability of a viscous flow for packed bed of bidisperse packing is derived based on calculation of drag force acting on each sphere and its predictions are compared with the experimental data and those from some relations previously suggested. It is found that our theory shows better agreement with experimental results than the previous studies and is proved to be quite simple and accurate in estimating the permeability.

• The Journal of Sustainable Design and Educational Environment Research
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• v.14 no.1
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• pp.1-9
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• 2015

The accurate estimation of construction cost is critical for effective budgeting and financing of the project. Accurate estimates also allow for informed decisions when considering the responsiveness of bids or proposals and for a contractor to better monitor construction progress. However, current method for construction cost of the public educational facility uses a basic criteria in Korea, e.g, construction cost per unit floor area. Therefore, the purpose of this study is to examine present architectural work cost rate of elementary, middle, and high school delivered by BTL(Build-Transfer-Lease). We examined real construction cost of educational facility according to level of school, such as elementary, middle, and high school. The examination revealed that unit price of BTL educational construction cost are different to the level of school, but the composing rate of architectural work cost of the educational facility are very similar. As a result, it is recommended that future researches are initiated to create specific methods to support the accurate cost estimation of educational facility.

• Journal of the Korean Geosynthetics Society
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• v.16 no.2
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• pp.47-54
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• 2017

This study aims to develop a bio-grouting material in a powder form like cement. Sand gel samples were produced with the ratio of sodium silicate No.3 to water (50 : 50, 35 : 65, 20 : 80), and the ratio of cement to bio-grouting material (100 : 0, 90 : 10, 70 : 30) to select a mixing ratio of bio-grouting, respectively, and then analyzed the geltime over time. The uniaxial compressive strength was evaluated to select and suggest a mixing ratio optimized for construction conditions. The indoor test reveals that preferred geltime and uniaxial compressive strength is obtained in 35 : 65 with respect to the ratio of sodium silicate No.3 to water, and 90 : 10 with respect to the ratio of cement to bio-grouting material to demonstrate best optimal mixing ratios.