• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.75-75
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• 2015

오염원과 취수장이 동일 구간 내에 공존하는 국내하천의 특성상, 하천 평면 내에서 오염물의 거동 및 혼합 특성을 보다 정확하게 해석하기 위해서는 2차원 이송-분산 모형의 적용이 필요하다. 이를 위해서는 2차원 모형의 주요 매개변수인 종분산계수와 횡분산계수의 적절한 입력이 매우 중요하다. 하지만 국내외적으로 횡분산계수에 대한 연구는 많이 진행된 반면, 현재까지 종분산계수에 대한 연구는 충분히 이루어지지 않은 실정이다. 분산계수를 결정하는 방법에는 실측된 농도 자료의 유무에 따라 크게 두 가지로 분류된다. 실측된 농도 자료가 없는 경우, 이론식이나 경험식을 이용하는 방법이 있다. 반면에 추적자 실험 등을 수행하여 실측된 농도 자료가 있는 경우, 모멘트법 또는 추적법을 적용하여 농도-시간 분포 곡선으로부터 분산계수를 계산하는 것이다. 모멘트법은 임의 지점에서 농도의 횡분포를 통해 얻을 수 있는 2차 모멘트의 종방향 변화율이 횡분산계수와 비례한다는 원리를 이용한 것이며, 추적법은 상류부의 관측된 농도를 입력자료로 하여 하류부의 농도를 계산한 후 계산된 농도와 실측된 하류부 농도의 비교를 통해 분산계수를 산정하는 방법이다. 본 연구에서는 불규칙한 단면 형상을 가지는 자연하천에서의 2차원 종 횡분산계수를 산정하기 위해서 Baek & Seo(2010)가 제안한 2차원 유관추적법(2D Stream-tube Routing Procedure)을 적용하였다. 본 연구에서는 국내 자연하천 중 다양한 사행형태를 갖으며 수질오염 사고의 위험이 높은 구간을 선정하고, 추적자로서 Rhodamine WT를 이용하여 현장실험을 수행하였다. 실험에서 수집된 수리량 및 농도자료로부터 추적자의 2차원적 거동을 분석하였으며, 2차원 유관추적법을 적용하여 종분산계수를 산정하였다. 그 결과 하폭 대 수심비(W/H)와 마찰손실관련 무차원변수(U/U*)의 증가에 따라 종분산계수가 증가됨을 확인 할 수 있었다. 본 연구에서 산출된 종분산계수와 선행 연구에서 수집된 자료를 이용하여 추정식을 개발하였다. 차원해석을 통해 무차원 종분산계수에 영향을 미치는 무차원 인자를 선별하고 회귀분석을 이용하여 종분산계수 추정식을 유도하였다. 추정식을 이용하여 산정한 종분산계수의 범위는 Elder (1959)가 제안한 이론값보다 약 10배 정도로 크게 나타났다. 혼합 특성이 밝혀지지 않은 자연하천에 2차원 확산모형을 적용하고자 할 때 본 연구에서 개발된 추정식으로부터 계산된 종분산계수를 사용할 수 있을 것이다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2A
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• pp.137-148
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• 2010

This study proposes the optimal ratio of vertical load-carrying capacity (${\beta}$) by investigating structural performances and economic efficiency in the extradosed bridges. Without design standards for the extradosed bridge, Japanese design standards have been used domestically. For the design live load, DL24 is found to be more adequate than DB24. Using the DL24 load, parameter studies are carried out. The parameters are 'main tower height', 'main girder stiffness', and 'cable arrangement'. As a result, it is found that one side cable-stayed extradosed bridges are more economical than double side cable-stayed extradosed bridges. This study also shows that when the ratio of vertical load-carrying capacity(${\beta}$) is 30~50% in the extradosed bridge with the ratio of tower height to main span length 1/6, the extradosed bridge is most economical because of the cable stress less than the allowable stress.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.4
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• pp.491-505
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• 2018

As an alternative to deep geological disposal technology, which is considered as a reference concept, the domestic applicability of deep borehole disposal technology for high level radioactive waste, including spent fuel, has been preliminarily evaluated. Usually, the environment of deep borehole disposal, at a depth of 3 to 5 km, has more stable geological and geo-hydrological conditions. For this purpose, the characteristics of rock distribution in the domestic area were analyzed and drilling and investigation technologies for deep boreholes with large diameter were evaluated. Based on the results of these analyses, design criteria and requirements for the deep borehole disposal system were reviewed, and preliminary reference concept for a deep borehole disposal system, including disposal container and sealing system meeting the criteria and requirements, was developed. Subsequently, various performance assessments, including thermal stability analysis of the system and simulation of the disposal process, were performed in a 3D graphic disposal environment. With these analysis results, the preliminary evaluation of the domestic applicability of the deep borehole disposal system was performed from various points of view. In summary, due to disposal depth and simplicity, the deep borehole disposal system should bring many safety and economic benefits. However, to reduce uncertainty and to obtain the assent of the regulatory authority, an in-situ demonstration of this technology should be carried out. The current results can be used as input to establish a national high-level radioactive waste management policy. In addition, they may be provided as basic information necessary for stakeholders interested in deep borehole disposal technology.

• Explosives and Blasting
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• v.28 no.2
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• pp.99-107
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• 2010

Domestic explosive demolition techniques have been developed and applied for low-rise structures up to now. However, the demand for the development of those techniques that can be applied economically, safely and environment-friendly rapidly increases because the old high-rise RC rahmen structures that were built since around 1970s are now required to rebuild. As a result, element technologies of explosive demolition for low-rise structures were applied to take advantage of technology in high-rise structures that performed application testing at Chungang Department demolition field in Daejeon city. It could judge elements technology establishment for high-rise structure demolition and field application and suggest the improvements when the problems occurred to develop High-rise building demolition techniques for method of protection a field test and the dust reduction test. The water cannon test was applied to reduce the dust site and the drilling tests are performed to select the best components for explosives demolition elements techniques of the reliability. This paper shows that we have the ability to remove a high-rise building using environmentally friendly safe and economical explosives demolition method. It would contribute to prevent a foreign company from entering the domestic market and should contribute to acquire competitiveness of domestic demolition industry.

• Journal of Korean Society of Forest Science
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• v.96 no.6
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• pp.644-651
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• 2007

This study compared and estimated the changes in carbon stocks and emissions of harvested wood products (HWP) by applying FAO statistics and domestic statistics for Korean HWP production, import, and export volume, which is almost always supposed to be included in the carbon emissions and removals inventory by country in negotiations since the 2nd commitment period (2013~2017) of the Kyoto Protocol, for assessing the changes in carbon stocks and emissions of HWP. As a result, when applying FAO statistics to the changes in carbon stocks of HWP as of 2005, stock-change approach (SCA) was estimated at 1.434 Tg C, atmospheric-flow approach (AFA) -1.330 Tg C, and production approach (PA) 0.597 Tg C. When applying Korean statistics, SCA was estimated at 1.246 Tg C, AFA -11.520 Tg C, and PA 0.444 Tg C. When applying FAO statistics to $CO_2$ emissions and removals from HWP, SCA showed a decrease of $-5,258Gg\;CO_2$ (removals), AFA showed an increase of $4,877Gg\;CO_2$ (emissions), and PA showed a decrease of $-2,189Gg\;CO_2$ (removals). When applying Korean statistics, SCA showed a decrease of $-4,569Gg\;CO_2$ (removals), AFA showed an increase of $5,573Gg\;CO_2$ (emissions), and PA showed a decrease of $-1,628Gg\;CO_2$, (removals). Therefore, the application of FAO statistics was shown to be more beneficial for the estimation of both the changes in carbon stocks and emissions of HWP by all methods other than that of Korean statistics.

• Korean Journal of Construction Engineering and Management
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• v.17 no.1
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• pp.10-17
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• 2016

Domestic CM market has continued to grow since the enactment of CM policies in 1996. In addition, future CM market is forecasted to have potential high growth. Therefore, it is necessary to apply various CM business models reflecting the owner's requirements and characteristics in order to improve in the CM industry and to strengthen the competitiveness in the overseas construction market. In this context, the purpose of this study is to suggest strategies of various CM applications based on comparison of 4 cases analyzed by 'business weight' and 'business depth' in terms of business function as well as by the types of 'CM market' and 'CM practice'. Result of this comparative analysis shows that each case presents differences in terms of type, business weight, and business depth of CM practice. However, domestic public CM services are currently being challenged to strengthen capability throughout the project life-cycle against the limitation of government's CM policies focused on the construction supervision. In order to address this problem, this study proposes the strategies of various CM applciations from several different perspectives

• Journal of Digital Convergence
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• v.19 no.12
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• pp.311-320
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• 2021

This study aims to explore the applicability of the HyFlex Learning Model as a new form of early childhood education in the post-COVID-19 era. In order to achieve the purpose of this study, first, the current challenges of early childhood education and the form of early childhood distance education in Korea were examined. Second, after examining the outline and characteristics of the HyFlex Learning Model(HLM) and the application cases of overseas institutions, in particular, the cases of applying the HLM in overseas early childhood education institutions were reviewed. Third, things to consider when applying the HLM in the field of early childhood education in Korea were derived. As a result, the HLM was investigated to be applicable not only in higher education but also in early childhood education as a model that emphasizes the learner's choice, learner-centered/directed, and activity. In order to apply the HLM to the early childhood education field in Korea, several points to be considered were proposed. Finally, the contribution of this study and further study were suggested.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.381_382
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• 2009

전력계통시스템에서 고효율 친환경 에너지 공급시스템 구축의 중요성이 크게 대두되면서 미래 전력계통시스템의 대안으로 초전도케이블이 제안되고 있으며, 이미 해외에서는 오래전부터 초전도케이블 연구개발을 수행하였으며 현재 실계통 적용 운전사례가 다수 있다. 국내에서도 2000년부터 본격적으로 초전도케이블에 대한 연구개발과 실증시험을 통하여 신뢰성 확보를 하였고 지금은 국내 실계통 적용 가능성을 확인하기 위한 배전급(22.9kV) 초전도케이블의 실계통 적용기술개발을 위한 연구과제가 KEPCO 주도로 LS전선이 참여하여 정부지원으로 착수하게 되었다. 본 논문에서는 대용량 친환경 초전도케이블의 실계통 적용을 위한 보호협조의 기술적 검토와 더불어 실계통에 적용하기 위한 기본적 설계 개념에 대하여 기술하고자 한다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.243-246
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• 2007

Traditionally, a domestic construction industry has recognized the relationship between a primary contractor and a subcontractor as a subordinated trade connection. To improve this unfair connection, the primary contractor and subcontractor's relationship must be recognized as Co-Development, and a new construction circumstances are needed, too. To apply benefit sharing to this relationship for Mutual Corporation, this needs the application method which could be reflected the specific aspects such as construction production method and production organization. Therefore, this study is aimed for the suggesting of basic data for Benefit Sharing application in the domestic construction industry by researching the problems and Benefit Sharing application States.

• Journal of the Korea Society of Computer and Information
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• v.27 no.9
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• pp.121-129
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• 2022

In this paper, the virtual environment using rack server type HPC and 3U VPX server type HPC was applied and tested to the basic functions of the Jangbogo-III class submarine combat system developed for the first time in Korea. Based on this test results, the possibility of applying virtualization to the domestic submarine combat system to be developed in the future is confirmed. Existing studies have been limited to deriving applicable virtualization solutions through simple performance analysis of virtualization solutions or applying virtualization to some functions of the surface ship combat system, but in this paper, the application of virtualization is expanded to the submarine combat system through testing.