• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.50.3-50.3
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• 2015

고립된 은하쌍 내의 두 은하의 스핀 각운동량의 각도 차이의 분포를 구하고 이를 통계적으로 분석한 결과를 관측 데이터와 수치 시뮬레이션 데이터 간에 비교함으로써 ${\Lambda}CDM$ 모형이 아닌 다른 우주 모형의 주요 변수를 규제할 수 있다. 이 연구에서는 결합된 암흑 에너지 (coupled dark energy, cDE) 모형의 주요 변수인 결합 함수를 규제하기 위해 서로 다른 조건의 cDE 모형과 ${\Lambda}CDM$ 모형에 따라서 생성한 수치 데이터의 스핀 정렬을 Argudo-Fernandez et al. (2015) 에서 인용한 관측 데이터의 스핀 정렬과 비교하였고, ${\Lambda}CDM$ 모형과 대부분의 cDE 모형의 수치 데이터는 관측 데이터와 부합하나 일부 cDE 모형은 부합하지 않아서 제외될 가능성이 높음을 확인하였다.

• Environmental and Resource Economics Review
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• v.20 no.3
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• pp.459-487
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• 2011

A/R CDM project has properties such as irreversibility and uncertainty that Real Option Analysis can be applied to its modelling. This study tries to model A/R CDM using Real Option under CER price uncertainty, and conducts empirical test with the Posco A/R CDM Project case. For precise comparison and decision-making, l-CER's expected present value is calculated from the Spot CER price. As a result, the critical value of the project is lower than the expected l-CER price, which means that the decision to invest made by the project owner is profitable. We can also find out that the level and the range of the discount rate, where is applied to, affect the result; the critical value of the project and the decision-making.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.73.2-73.2
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• 2010

암흑에너지는 우주상수만으로 여러 우주론 관측 자료들을 잘 설명하고 있지만, 최근 SN Ia 자료가 축적됨에 따라 암흑에너지의 상태방정식 파라미터 $\omega$가 우주상수에서와 같이 -1인 상수인지, 시간에 따라 변하는지를 알아내기 위한 연구가 진행되고 있다. 본 연구에서는 $\omega$가 시간에 따라 갑자기 변하는(sudden jump) transition-$\omega$CDM 모형을 이용하여 SN Ia 자료를 Markov Chain Monte Carlo(MCMC) 방법을 통해 분석했다. Transition-$\omega$CDM 모형에서는 상수인 $\omega$의 값이 임의의 적색이동에서 변한다고 가정하였다. 분석에 사용된 SN Ia 데이터는 307개의 Union 자료와 90개의 CfA3 SN Ia가 추가된 Constitution 자료이며 개별적으로 분석됐다. 그 결과 transition 시기 전후 $\omega$ 값들의 확률밀도분포를 얻어내었고, 이를 통해 SN Ia의 특성을 조사하였다.

• Korean Journal of Construction Engineering and Management
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• v.15 no.1
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• pp.111-121
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• 2014

The Clean Development Mechanism (CDM) allows New & Renewable Energy projects to make additional income by selling CER's, which represent the amount of Green House Gases(GHG) that is reduced in the project. However, forward contracts used to hedge fluctuating market prices does not allow projects to sell CER's at a premium. As an alternate approach to maximize CER revenue, CER's are modeled as a 'real option', in which CER's are sold only above the desired sales price. Using the Binomial Option Pricing model, the resultant lattices are used to determine whether to sell, defer or abandon the option at individual nodes. Overlaying Pascal's Triangle on the lattices also enabled the calculation of the annual probabilities for deferring CER sales without incurring downside losses. Application to an actual Landfill Gas project showed increased overall NPV, and that CER sales could be deferred at a maximum of 2 years. The proposed framework allows transparency in the analysis and provides valuable and strategical information when making investment decisions related to CER sales of CDM projects.

• Environmental and Resource Economics Review
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• v.19 no.4
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• pp.829-852
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• 2010

The investment in Clean Development Mechanism (CDM) projects is increasing rapidly as the first implementation period began in 2008. This paper examines on the optimal level of primary Certified Emission Reduction (CER) price, subsidiary original projects investment cost and expected issues CER per year, using UNFCCC CDM Project Design Document (PDD) data. Real option model is developed to incorporate a case where the investment is irreversible and underlying asset price is uncertainty. This study employs Real option approach which allow the optimal level regard as economic feasibility of CER price has analyzed with NPV (Net Present Value) and Black-Scholes call option(Real option) value. Finally, CER supply curve and price elasticity of supply are estimated.

• Korean small business review
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• v.41 no.3
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• pp.49-75
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• 2019

Market instability offers opportunities as well as the need for careful innovation strategies and learning for a company's survival. Companies that find new opportunities decide to carry out innovation and decide on the size of their investments by considering their position in the market they are aiming for and the intensity of competition. This study was conducted to check whether obstacles to innovation face by SMEs in the manufacturing sector vary depending on the stage of corporate growth and to identify the impact of the government support system on the decision-making process on the performance of innovation. According to the analysis, there were differences in obstacles to innovation depending on the stage of corporate growth. It was found that more innovative SMEs are, more obstacles they face, and to overcome such obstacles, they try to access government support systems more. In addition, the use of a government support system eliminated obstacles to innovation, and the positive and significant effects of investing in innovation were identified. This study is meaningful in that it explicitly approached these hypotheses by applying a multistage model to the process of innovation carried out by SMEs in the manufacturing sector.

• School Mathematics
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• v.16 no.2
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• pp.387-407
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• 2014

Gender differences have been given major attention in mathematics education in the context of pursuing gender equity in instructional and learning environment. It had been traditional belief that male students would outperform female students in mathematics, especially in the areas as geometry. This belief has been given doubts by cumulated empirical evidences that gender differences are gradually diminishing or even reversing its direction as time goes on. In this study, gender differences in geometry were explored using TIMSS 8th grade mathematics data administered in TIMSS 2003, 2007, and 2011, based on a cognitive diagnostic modeling(CDM) approach. Among various CDM models, the Fusion model was employed. The Fusion model has advantages over other CDM models in that it provides more detailed information about gender differences at the attribute level as well as item level and more mathematically tractable. The findings of this study show that Attribute 3(Three-dimensional Geometric Shapes) revealed statistically significant gender differences favoring male students in TIMSS 2003 and 2007, but did not show significant differences in TIMSS 2011, which provides an additional empirical evidence supporting the recent observation that gender gap is narrowing. In addition to the general trends in gender differences in geometry, this study also provided affluent information such as gender differences in attribute mastery profiles and gender differences in relative contributions of each attribute in solving a particular item. Based on the findings of the CDM approach exploring gender differences, instructional implications in geometry education are discussed.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.4
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• pp.131-139
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• 2022

The aim of this study was to assess the feasibility of a landfill project to reduce greenhouse gas (GHG) from La Chureca Landfill in Managua, Nicaragua ("Project"). The feasibility study involved surveying the status and composition of waste on its way in to the landfill and projecting GHG emissions from the landfill. A projection of the GHG emissions with the IPCC model based on the survey results indicated the period 2006 to 2043 would see mean yearly GHG emissions of 290,147 ton-CO₂/year with model certainty not considered, and 217,610 ton-CO₂/year with model certainty considered. Thus, the result exceeded the corresponding median and mean values of other CDM projects implemented in Central America, even after model uncertainty was considered together with the conservative estimation of carbon capture efficiency. The similar result was produced even with an analysis of sensitivity to error factors. All the findings of the study are expected to be applicable as basic data for deciding about whether & how to proceed with the Project.

• Journal of Soil and Groundwater Environment
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• v.12 no.5
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• pp.33-36
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• 2007

In recent years the convective-dispersive equation has been often discredited in predicting subsurface solute transport under field conditions due to presence of preferential flow paths. Kim et al. (2005) proposed a simple equation that can predict the breakthrough of solutes without excessive data requirements. In their Generalized Preferential Flow Model (GPFM), the soil is conceptually divided in a saturated "distribution layer" near the surface and a "conveyance zone" with preferential flow paths below. In this study, we test the model with previously published data, and compare it with a classical convective-dispersive model (CDM). With three parameters required-apparent water content of the distribution zone, and solute velocity and dispersion in the conveyance zone-GPFM was able to describe the breakthrough of solutes both through silty and sandy loam soils. Although both GPFM and CDM fitted the data well in visual, variables for GPFM were more realistic. The most sensitive parameter was the apparent water content, indicating that it is the determining factor to apply GPFM to various soil types, while Kim et al. (2005) reported that changing the velocity of GPFM reproduced solute transport when same soils were used. Overall, it seems that the GPFM has a great potential to predict solute leaching under field conditions with a wide range of generality.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.11
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• pp.2238-2249
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• 2015

The purpose of this study is to analyze the relations of innovation and productivity following the introduction of ICT and the effects in the process of innovative investments activity-innovation-productivity, not only by finding causes and effects. For this purpose we conducted surveys of SMEs classified into 7 categories by type of business. To put it concretely, this study was performed to find out the foactors which allow companies to secure competitiveness by enhancing of innovative measures through ICT, and to further analyze the political implications for the development of small and medium-size business by conducting an empirical analysis of the process, from the determination of innovative investments all the way through to production. Analysis model used CDM model using econometric methods such as multiple regression analysis and multinominal logit analysis to produce results. Also we established and analyzed models of innovation investment determinants, innovation determinants and productivity determinants to analyze specifically the relations between ICT and productivity.