• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1799-1801
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• 2005

최근 세계 여러 나라에서는 적정한 신뢰도나 경제성을 고려해 직류송전방식에 대한 관심이 날로 높아져 가고 있다. 우리나라도 부하가 밀집된 수도권으로 올라오는 송전선로의 병목현상으로 역률이나 주파수 등의 변화가 점점 심해지면서 전력계통의 신뢰도와 안정성에 문제가 발생할 수 있다. 본 연구에서는 우리나라 계통의 부하집중지역인 수도권을 대상으로 최적 직류 송전 경로를 임의로 선정하여, 직류 송전 방식을 건설하였을 때와 가공 송전 방식을 건설하였을 때의 건설비, 운영비, 유지보수 비용 등의 경제성을 비교 검토하고 이에 따른 장점과 단점을 분석함으로써 직류송전방식의 타당성을 검토해 본다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.4
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• pp.154-159
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• 2010

Recent concrete structures have been being constructed with higher strength concrete than normal strength concrete. Therefore, it is necessary to review the applicabilities of current design codes and models for the prediction of mechanical behaviors of concrete materials such as creep. To investigate the applicability of creep model with the consideration of the strength level of concrete, three current models (ACI 209R, CEB-FIP MC90 and EC2) were studied and compared with series of experimental results. It was shown that EC2 model which is the updated model of CEB-FIP MC90 better predicts creep coefficient for high strength level concretes and showed relatively good agreements with experimental data.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.370-375
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• 2012

국가개발연구원(KDI)에서는 새만금에 40MW 용량의 국산 풍력발전단지 조성을 위한 예비타당성 조사를 실시하였다. 본 사업에 대한 KDI의 비용편익 분석 결과 순 현재가치가 0보다 작고, B/C 비율은 0.73으로 경제적 타당성이 나타나지 않았다. 하지만 모든 비용과 편익을 화폐가치로 환산해 내는 비용편익분석은 여러 가지 외부효과로 인해 사업의 타당성 연구자들에 의해 주관적인 결과물이 나오기도 한다. 이에 따라 본 논문에서는 새만금 풍력발전 시범단지의 경제성 평가 재검토 연구를 실시하였다. 본 논문에서는 기존 경제성 평가 항목에 대하여 여러 가지 쟁점을 제시하고, 그 중에서 대기오염물질 저감 비용과 학습효과(learning effect)로 인한 비용 절감 편익을 추가적으로 산정하였다. 여기서 학습효과의 학습속도(learning rate) 를 세 가지 시나리오로 나누어 분석하였다. 두 가지의 추가 편익을 KDI의 기존 예비타당성 조사 분석에 추가한 순 현재가치는 상당한 양의 값이 나왔고, B/C 비율은 8.8 로 편익이 비용에 비해 크게 증가했다. 이러한 항목들의 포함 여부에 따라 타당성 결과가 현저하게 달라짐을 알 수 있다. 향 후 비용편익 분석이 정책 결정에 적절히 반영되기 위해서는 외부효과를 고려한 환경 비용, 그리고 학습효과와 같은 추가적인 사항들이 면밀히 검토되어야 한다. 시장에 기반하지 않은 이러한 외부효과로 인한 항목들은 대상과 시기에 따라 매우 다른 결과를 보여주기에 이에 대한 세부적인 연구가 필요한 시점이다.

• Journal of the Korean Society for Library and Information Science
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• v.52 no.2
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• pp.125-142
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• 2018

Local innovation cities that have recently been being constructed have a large share of the population with highly educated young family with children. There are high demand for children's libraries because of this high percentage of children in the population. In this regard, this study analyzed the economic feasibility of establishing a new children's library in an innovation city as viewed through the case of the C innovation city, where population inflows are increasing recently. In this study, based on a survey, we conducted a cost benefit analysis, as estimating the cost of constructing the library and calculating the benefits from the construction. The economic feasibility was analyzed by calculating the benefit cost ratio, net present value, and internal rate of return.

• Journal of the Korea Concrete Institute
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• v.28 no.1
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• pp.23-31
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• 2016

In this study, Based on the constructed model in advance, we suggested the macro prediction method of shrinkage cracking reduction in concrete using expansive additives, and the method was verified. In addition, extended application of model to building, the strain of walls and slabs on building was estimated by model and the generated stress was estimated thereby comparing this with the result by existing method to verify the model's applicability and the validation of our model. From examination of theoretical model for concrete using expansive additives to examination for building levels, furthermore suggests the macro prediction method for shrinkage reduction and cracking control effects was can be supply practical data in application of expansive concrete and utility in the future.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.1
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• pp.102-109
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• 1986

Based on the Hartenberg-Denavit symbolic equation, which is one of equations for the kinematic analysis of three dimensional (3-D) linkage, a generalized kinematic motion equation is derived utilizing Euler angles and employing the coordinates transformation. The derived equation can feasibly be used for the motion analysis of any type of 3-D linkages as well as 2-D ones. In order to simulate the general motion of 3-D linkgages on digital computer, the generalized equation is programmed through the process of numerical analysis after converting the equation to the type of Newton-Raphson formula and denoting it in matrix form. The feasibility of theoretically derived equation is experimentally proved by comparing the results from the computer with those from experimental setup of three differrent but generally empolyed 3-D linkages.

• Journal of the Korean Institute of Gas
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• v.4 no.4 s.12
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• pp.50-57
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• 2000

Past accidents have shown that vapor cloud explosions are the predominant cause of the largest losses in the chemical and petrochemical industries due to the generation of significant overpressures. Prediction of such overpressure is of great concern and a knowledge of the likely overpressure is needed for the design of equipment, safety cases and emergency planning. For these reasons, risk assessment for vapor cloud explosion is crucial and this assessment can be carried out using the different models including TNT-Equivalency, TNO Hemispherical, TNO Multi-Energy and CFD models. Accordingly, in this paper, the published VCE prediction models are reviewed to provide a critical comparison of the different models used for the quantification of explosion hazards, in terms of the fundamental assumptions employed, and their predictive accuracy

• Journal of Environmental Impact Assessment
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• v.31 no.4
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• pp.250-264
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• 2022

The development projects subject to health impact assessment (HIA) in the current environmental impact assessment (EIA) system are limited to some projects under Article 12 of the Enforcement Decree of the Environmental Health Act (Additional Assessment Objects Subject to Health Impact Assessment Items), but health impact-related matters are being evaluated and reviewed during consultation. In particular, when a development site is planned around some pollutant sources in a residential development plan, it is evaluated and reviewed whether the site meets the risk criteria through a current concentration survey of major hazardous air pollutants. This study prepared a quantitative method to confirm the validity of the location of the residential area to be developed in the residential development plan and proposed a plan to expand the project subject to HIA within the EIA procedure. A detailed methodology was proposed by reviewing the screening and scoping procedures of the EIA system, and a case analysis of the urban development plan discussed in the past was conducted to verify the methodology.

• 한국체육학회지인문사회과학편
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• v.55 no.6
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• pp.417-435
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• 2016

The purpose of this study was to develop a valid, reliable instrument to measure perceived value for Taekwondo performance spectators. The perceived value scale for Taekwondo performance spectators was developed in eight phases. For the development spectators perceived value scale (1) literature review, (2) preliminary factors and items selected, (3) assessment of the items, (4) pilot test, (5) data sampling, (6) validity of development scale, (7) assess reliability of items and, (8) predictive validity of development items. Based on three processes, a new perceived value of Taekwondo performance spectators scale with six factors(cultural, social, hedonic, aesthetic, moral and utilitarian value) and 19 items were developed. The result of predictive validity of development items: first, cultural, social, aesthetics, moral of perceived value had significantly influence on spectators attitude. Second, social, hedonic, utilitarian of perceived value had significantly influence on spectators satisfaction. Third, cultural, social, aesthetics perceived value had significantly influence on future consumption behavior of spectators.

• Journal of the Korean Data and Information Science Society
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• v.21 no.6
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• pp.1203-1209
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• 2010

Internet addiction is a serious social problem in information society. The purpose of this study is to develope a small diagnostic scale in order to detect internet addiction easily. The reliability and validity of K-scale and Kimberly Young-scale is investigated. Five small diagnostic scale is suggested by factor analysis and regression. The comparision of these small scale is established by correlation coefficient, chi-square test, gamma value of concordance in contingency table. In view of reliability and validity, we suggest a small diagnostic scale. The results of this study may be useful to detect internet addiction by oneself.