• 자원ㆍ환경경제연구
• /
• 제21권3호
• /
• pp.441-464
• /
• 2012

2000년 이래로 석유, 가스 등 에너지 가격이 지속적으로 상승하면서 에너지 안보는 그 어느 때보다 중요한 이슈가 되었다. 그 결과 에너지 확보를 위해 세계각국은 적극적으로 해외 자원개발에 나서고 있는 상황이며 관련 경쟁은 점점 치열해져 가고 있다. 이와 관련하여 본 연구에서는 우리나라가 비교적 쉽게 접근할 수 있는 독립계 E&P기업의 투자 행태 분석을 시도하였다. 본 연구에서는 자원의 고갈을 고려한 실물옵션 모형을 이용하여 북미 독립계 E&P기업의 투자 옵션에 대하여 분석하였다. 분석결과, 대상기간인 2004년부터 2008년까지의 전반적인 시장 환경에서 독립계 E&P기업은 석유 프로젝트와 가스 프로젝트 모두 충분한 투자 타당성을 가지고 있는 것으로 나타났다. 특히 석유 프로젝트가 가스 프로젝트보다 기대 수익이 더 높은 것으로 나타났는데, 이는 가스의 가격이 석유보다 낮고 가스 가격의 변동성이 석유가격보다 높은 것에서 기인한다.

• 한국에너지공학회:학술대회논문집
• /
• 한국에너지공학회 1998년도 추계 학술발표회 논문집
• /
• pp.3-8
• /
• 1998

The present work proposes the potential fuzzy framework, based on fuzzy set theory, for supporting decision-making problems, especially, selection problems of a best design in the area of nuclear energy system. The framework proposed is composed of the hierarchical structure module, the assignment module, the fuzzification module, and the defuzzification module. In the structure module, the relationship among decision objectives, decision criteria, decision sub-criteria, and decision alternatives is hierarchically structured. In the assignment module, linguistic or rank scoring approach can be used to assign subjective and/or vague values to the decision analyst's judgment on decision variables. In the fuzzification module, fuzzy numbers are assigned to these values of decision variables. Using fuzzy arithmetic operations, for each alternative, fuzzy preference index as a fuzzy synthesis measure is obtained. In the defuzzification module, using one of methods ranking fuzzy numbers, these indices are defuzzified to overall utility values as a cardinality measure determining final scores. According these values, alternatives of interest are ranked and an optimal alternative is chosen. To illustrate the applicability of the framework proposed to selection problem, as a case example, the best option choice of four design options under five decision criteria for primary containment wall thickening around large penetrations in an advanced nuclear energy system is studied.

• Steel and Composite Structures
• /
• 제12권3호
• /
• pp.249-260
• /
• 2012

In this study, stress and deflection behaviours of T-type welding joint applied to HE200M steel beam and column were investigated in finite element method (FEM) under different distributed loads. In the 3D-FEM modelling, glue option was used to contact between steel materials and weld nuggets. Geometrical model was designed as 3-dimensional solid in ANSYS software program. After that, homogeneous, linear and isotropic properties were used to design to materials of model. Solid-92 having 3-dimensional, 4 faced and 10-noded was selected as element type. In consequence of mesh operation, elements of 13285 and nodes of 28086 were occurred. Load distribution was applied to top surface of steel beam to determine behaviours of stress and deflection. As a result of FEM analysis applied with the loads of 55,000 N, 110,000 N and 220,000 N, maximum values were obtained as 116 N/$mm^2$, 232 N/$mm^2$ and 465 N/$mm^2$ for stress and obtainedas 1,083 mm, 2,166 mm and 4.332 mm for deflection, respectively. When modelling results and classical calculation values were compared, it was obtained difference of 10 % for stress values and 2.5% for deflection values.

• 한국환경과학회지
• /
• 제31권8호
• /
• pp.727-733
• /
• 2022

The contingent valuation method (CVM) is one of the most commonly used and effective methods to evaluate non-use value of resources. Reasonable application of CVM to value the cultural heritage is the key process of evaluation. CVM was used to evaluate the non-use value of cultural heritage of Taishan Mountain combined with questionnaire survey and field research in this study. The results indicated that the importance of the degree of the three components of non-use value was heritage value ranked highest (40.22%) > followed by existence value (38.58%) >then option value (21.20%). In addition, the rate of willingness to pay was 54.52%, the average and median values of per person were 40.17 CNY·a^-1 and 20.00 CNY·a^-1 and the non-use values of Taishan Mountain cultural heritage was 33 million CNY·a^-1. The median value of WTP was consistent with Asian countries but was lower than European and American countries. Factors influencing WTP showed that monthly income and satisfaction with Taishan Mountain were correlated to WTP, and family location and willingness to revist were correlated remarkably with WTP. In addition, monthly income was correlated remarkably with WTP value, however other factors were not. The results showed the importance and necessity of protective development of Taishan Mountain cultural heritage, which would be used as an important reference for decision makers.

• Toxicological Research
• /
• 제29권2호
• /
• pp.99-106
• /
• 2013

Clostridium difficile infection (CDI) has become a significant threat to public health. Although broad-spectrum antibiotic therapy is the primary treatment option for CDI, its use has evident limitations. Probiotics have been proved to be effective in the treatment of CDI and are a promising therapeutic option for CDI. In this study, 4 strains of lactic acid bacteria (LAB), namely, Lactobacillus rhamnosus (LR5), Lactococcuslactis (SL3), Bifidobacterium breve (BR3), and Bifidobacterium lactis (BL3) were evaluated for their anti-C. difficile activity. Co-culture incubation of C. difficile ($10^6$ and $10^{10}$ CFU/ml) with each strain of LAB indicated that SL3 possessed the highest antimicrobial activity over a 24-hr period. The cell-free supernatants of the 4 LAB strains exhibited $MIC_{50}$ values between 0.424 mg/ml (SL3) and 1.318 (BR3) mg/ml. These results may provide a basis for alternative therapies for the treatment of C. difficile-associated gut disorders.

• 경영과학
• /
• 제31권2호
• /
• pp.71-86
• /
• 2014

There is a growing need for technology transactions between the technology providers, who develop technologies, and the technology consumers, who purchase and commercialize technologies, to be smooth, when technologies, as intangible assets, are traded as items that can be purchased and sold. In response to these challenges, this study examines new approaches to assessing the fair market value of technologies. Because corporations are the main force behind technology development and commercialization in the existing business environment, applying one valuation method to technology assets is viable; however, as the subjects of technology development and technology commercialization are separate, the need for price negotiations between the subjects of technology transaction has grown. Moreover, as the investigations into and the application of transaction prices have been performed separately by technology providers, technology consumers, and technology assessment financial institutions, the research on technology valuation methods has shown that there are differences in perceived transaction prices between the subjects involved. This research presents a new method, appropriate to technology transactions; unlike existing methods, it grants option values to the technology provider and newly defined key variables to the technology consumer.

• 한국축산식품학회지
• /
• 제41권1호
• /
• pp.8-15
• /
• 2021

Vegetarians have claimed and actively promoted the advantages of plant-based alternative milks as the best option for human nutrition and health, compared to the natural dairy milk. However, numerous scientific evidences and reports have demonstrated that the natural milk possesses more beneficial nutrients and bioactive components than artificially manufactured plant-derived milks. The biochemical and nutritional advantages and functionalities of natural dairy milk cannot be replaced by man-made or crafted plant-based beverage products. On the other hand, the tremendous increase in production and consumption of the plant-based alternative milks in recent years has led a serious business downturn in traditional roles and stability of the dairy industry, especially in the major dairy producing Western countries. Although plant-based milk alternatives may have some benefits on nutrition and health of certain consumers, the plant-derived alternative milks may not overshadow the true values of natural milk. Milk is not a high fat and high cholesterol food as animal meat products. Unlike plant-based alternative milks, natural milk contains many bioactive as well as antiappetizing peptides, which can reduce body weight. It has proven that taking low-fat, cultured and lactase treated milk and dairy products with other diversified nutritionally balanced diets have been shown to be healthier dietary option than plant-based milk/foods alone.

• 자원ㆍ환경경제연구
• /
• 제21권3호
• /
• pp.465-491
• /
• 2012

지구온난화에 대처하기 위한 한 가지 방안으로, 최근 녹색성장과 녹색금융이 활성화되고 있다. 특히, 금융시장을 통하여 기온상승에 대한 적응을 가능케 하는 기온파생상품은 녹색금융의 능동적 형태로서 주목받고 있다. 본 논문에서는 서울의 일별평균기온에 대한 특성을 파악하여 계절성, 주기성 등을 포함한 일별평균기온 예측모형을 설정한 후, 기온옵션의 일종인 CDD 옵션가격과 HDD 옵션가격을 시뮬레이션을 통해 분석한다. 오차항의 주기성 모형여부에 따라 구분하여 분석을 진행한 결과, CDD 콜옵션과 HDD 풋옵션의 위험중립가치가 시간이 지남에 따라 상승한 것으로 나타나 기온상승의 추세를 금융시장에서 정량적으로 파악할 수 있는 것으로 나타났다. 기존 모형과는 달리, Vasicek 모형에 기반한 CDD 콜옵션가치분석시, 특정 행사가격 이상에서 옵션의 가치가 존재하여, 기온상승위험회피를 위한 금융상품으로서 활용이 가능하다.

• 한국건설관리학회논문집
• /
• 제18권2호
• /
• pp.81-90
• /
• 2017

임진강 유역은 1996년부터 1999년까지 3번의 대규모 홍수가 발생하여 많은 인명피해와 9천억원의 재산피해를 입었다. 우리나라는 기후변화로 인하여 홍수피해가 앞으로 증가할 것으로 예상된다. 본 연구는 기후시나리오를 활용하여 미래의 홍수피해를 예측하고, 실물옵션 기반 경제성분석 방법을 제시하였으며, 임진강유역의 홍수방지시설물 투자사업의 사례연구를 통해 경제성분석을 실시하였다. RCP (Representative Concentration Pathway) 기후시나리오에서 모의된 강수량 자료를 활용하여 홍수피해액을 계산하고, 홍수방지시설물 투자에 의한 저감이익을 분석하였다. 향후 RCP8.5와 RCP4.5 기후시나리오가 실현되는 조건을 가정하여 홍수피해 저감이익의 변동성을 구하고, 2071년에 200년 재현주기에 적응하도록 하는 확장을 위한 투자를 할 수 있는 확장옵션을 적용하여 프로젝트의 옵션가치를 구했다. 옵션가치 분석결과, 두 가지 시나리오 하에서 경제성을 확보하고 있음을 확인하였고, RCP8.5 기후시나리오가 실현될 때가 RCP4.5의 경우보다 홍수피해 저감이익이 더 많이 발생하였다. 본 연구는 정부 의사결정권자가 실물옵션분석방법을 활용하여 홍수방재시설물의 경제성분석에 기후변화 불확실성을 고려할 수 있도록 도와줄 것으로 기대되며, 기후시나리오에서 제공하는 강우자료를 활용하여 기후위험요소를 경제적 가치로 정량화하는 방법을 제시하였다.

• Journal of Astronomy and Space Sciences
• /
• 제37권1호
• /
• pp.1-9
• /
• 2020

Frozen orbit is an attractive option for orbital design owing to its characteristics (its argument of pericenter and eccentricity are kept constant on an average). Solar sails are attractive solutions for massive and expensive missions. However, the solar radiation pressure effect represents an additional force on the solar sail that may greatly affect its orbital behavior in the long run. Thus, this force must be included as a perturbation force in the dynamical model for more accuracy. This study shows the calculations of initial conditions for a lunar solar sail frozen orbit. The disturbing function of the problem was developed to include the lunar gravitational field that is characterized by uneven mass distribution, third body perturbation, and the effect of solar radiation. An averaging technique was used to reduce the dynamical problem to a long period system. Lagrange planetary equations were utilized to formulate the rate of change of the argument of pericenter and eccentricity. Using the reduced system, frozen orbits for the Moon sail orbiter were constructed. The resulting frozen orbits are shown by two 3Dsurface (semi-major, eccentricity, inclination) figures. To simplify the analysis, we showed inclination-eccentricity contours for different values of semi-major axis, argument of pericenter, and values of sail lightness number.