• 한국수소및신에너지학회논문집
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• 제19권4호
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• pp.322-330
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• 2008

This paper deals with an economic evaluation of domestic photobiological hydrogen production. We evaluate the economic feasibility of domestic photobiological hydrogen production utilizing green algae and cyanobacteria. In addition, we make some sensitivity analysis of hydrogen production prices by changing the values of input factors such as the price of a photo-bioreactor and the value of solar to hydrogen efficiency. The estimated hydrogen production price of the two-step indirect biophotolysis was 12,099won/kg$H_2$. It is expected that the hydrogen production price by the two-step indirect biophotolysis can be reduced to 2,143won/kg$H_2$ if the solar to hydrogen efficiency is increased to 10% and the price of a photo-bioreactor is decreased to $25/$m^2$. The two-step indirect biophotolysis is evaluated as uneconomical at this time, and we need to enhance the solar to hydrogen efficiency and to reduce the prices of the photo-bioreactor and system facilities.

• 한국항만경제학회지
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• 제36권1호
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• pp.183-196
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• 2020

현재까지 목포항의 효율성을 분석하고 우리 나라의 다른 주요 무역항만과 비교하여 항만의 개발 방향을 개선한 연구는 많지 않다. 본 논문에서는 Malmquist Productivity Index (MPI)와 함께 DEA (Data Envelopment Analysis) 모형을 사용하여 목포항을 중심으로 우리나라 주요 무역항만의 효율성과 생산성을 측정한다. 첫째, 항만의 기술적 또는 운영 규모에 따라 어떤 항만이 효율적이거나 비효율적인지, 그리고 몇 년 동안 어떤 항만이 생산성을 유치할 수 있는지 파악하고자 한다. 둘째, 이 연구는 어떤 항만의 그룹이 효율성 점수가 높거나 낮은지 분류하는 데 Fuzzy C-means (FCM) 클러스터링 방법을 적용한 후 목포항의 개선 방안을 제시하고 자 한다.

• Environmental Engineering Research
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• 제25권1호
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• pp.71-79
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• 2020

This paper uses super-efficiency DEA model and Malmquist index to evaluate the carbon emission efficiency (CEE) values of the nine western provinces along the "Silk Road Economic Belt" for the period from 2000 to 2015, and analyses the influencing factors of the CEE. The major findings of this study are the following: (1) the overall CEE of the nine western provinces is not high, and there are significant inter-provincial differences in the CEE. Meanwhile, the provinces with higher levels of economic development generally have higher CEE. (2) The annual total factor productivity (TFP) of the nine western provinces, which is mainly determined by technological change, is greater than 1. Moreover, the total average growth rate of the TFP is 15.5%. (3) The CEE of the nine western provinces is not spatially dependent. In addition, the urbanization, openness, use of energy-saving technologies and research and development (R&D) investment have a significant positive impact on the CEE values, while the industrial structure, foreign direct investment, fixed asset investment, government expenditure levels and energy structure have a significant negative impact on the CEE. Among them, R&D investment is the primary factor in promoting the development of CEE, and the government expenditure has the greatest negative impact on the CEE.

• 한국환경과학회지
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• 제22권3호
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• pp.281-289
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• 2013

For the purpose of evaluating the eco-efficiency(EE) on surplus heat generated from industrial process, techniques of life cycle assessment are adopted in this study. Because it can be indicated both environmental impacts and economic benefits, EE is well known as a useful tool for symbiosis network on the sustainable development of new projects and businesses. To evaluate environmental impacts, the categories were divided into two areas of resource depletion and global warming potential. It can be seen that environmental impact increased a little but much higher economic benefit on the company, environmental performance and economic value were improved on the apartment by the district heating, respectively. In result, eco-industrial park(EIP) project on surplus heat should be found sustainable new business because the EE was in the area of fully positively eco-efficiency and, moreover resource depletion was taken place than the reduction of greenhouse gas.

• 한국수소및신에너지학회논문집
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• 제21권1호
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• pp.64-71
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• 2010

This paper deals with an economic evaluation of domestic immersing type photoelectrochemical hydrogen production. We also make some sensitivity analysis of hydrogen production prices by changing the values of input factors such as the initial capital cost, the solar to hydrogen conversion efficiency, and the system duration time. The hydrogen production price of the immersing type photoelectrochemical system was estimated as 8,264,324 won/$kgH_2$. It is expected that the production cost by photoelectrochemical hydrogen production can be reduced to 26,961 won/$kgH_2$ if the solar to hydrogen conversion efficiency is increased to 14%, the system duration time is increased to 20,000 hours, and the initial capital cost is decreased to 10% of the current level. The photoelectrochemical hydrogen production is evaluated as uneconomical at this time, and we need to enhance the solar to hydrogen conversion efficiency and the system duration time as well as to reduce prices of the system facilities.

• 한국항만경제학회지
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• 제32권2호
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• pp.123-135
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• 2016

본 연구는 자료포락분석법(DEA)을 이용하여 기업의 경영관리비용인 접대비, 광고 선전비, 인건비를 중심으로 국내 해운기업의 경영효율성을 평가하고자 하였다. 분석의 대상은 2010년부터 2014년까지 국내증시에 상장된 해운기업이다. 투입변수로 접대비, 광고 선전비, 인건비를 설정하였으며 산출변수는 매출액과 당기순이익으로 하였다. 본 연구에서는 기술효율성, 순수기술효율성, 규모효율성 및 규모수익을 도출하였으며 비효율 DMU의 효율성 개선방안을 제시하였다. 효율성 측정 결과 CCR모형의 기술효율성 분석에서 6개의 DMU와 BCC모형의 순수기술효율성 분석에서 8개의 DMU가 효율적인 상태인 것으로 나타났다. 규모의 수익측면에서는 전체 DMU의 24%인 6개의 DMU가 규모수익체증상태이며, 전체 DMU의 52%인 13개 DMU가 규모수익체감상태인 것으로 나타났다. 기술효율성 분석결과 복수의 효율적인 상태의 DMU가 존재하여 초효율성 분석을 실시한다. 본 연구에서는 초효율성 분석 결과 가장 효율성이 높은 DMU의 효율성 수준은 1.314, 다음은 1.243으로 나타났다. 이는 광고 선전비, 접대비, 인건비 투입에서 각각 31.4%, 24.3% 증가시키더라도 현재의 효율적인 상태를 유지할 수 있다는 것을 의미한다. 본 연구는 해운기업의 접대비와 광고 선전비, 인건비의 효율성을 평가하고, 초효율성 분석을 통해 의사결정단위의 순위를 파악하였으며 비효율 의사결정단위의 비효율성 개선을 위한 목표치를 제시하였다는데 의의가 있다.

• 자원환경지질
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• 제17권4호
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• pp.237-243
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• 1984

최대 엔트로피 스펙트럼 분석 (Maximum entropy spectral analysis)에 관한 Burg알고리즘 (algorithm)의 계산효율과 안정성에 대하여 검토하였다. Burg의 방법은 Yule-Walker의 방법보다 계산효율이 낮을 뿐만 아니라 그의 수학적 불합리성으로 인하여 간혹 불안전할 때가 있다. 이러한 불합리성을 인공 시계열의 해석을 통하여 증명한 후 보다 안정하고 효과적인 방법을 소개하였다. 또한 파워 스펙트럼밀도 (Power spectral density)의 계산에서 Goertzel알고리즘을 이용하는 효율적인 방법도 소개하였다.

• 전기학회논문지
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• 제64권2호
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• pp.349-352
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• 2015

This paper estimates electrical fire damage cost-effect to analyze electrical safety efficiency by applying a cost-benefit analysis method for analyzing the efficiency of a business public interest. Electrical fire loss statistics data was presented as direct costs and casualties, including deaths due to an electrical fire, this paper adds overhead "Incidental Cost of Accidents to the Employer" by W. H. Heinrich was applied to estimate the cost of economic loss. Also wounded, including the loss of human deaths by referring to the car accident insurance claims costs and human development estimated the losses caused by an electrical fire. And to perform a cost-benefit analysis of the electrical safety as a result of future work. In this paper, the economic effect of the electric field of safety and public interest work to systematically presented.

• 전기학회논문지
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• 제61권7호
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• pp.950-956
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• 2012

As development of battery technologies, the installation of Battery Energy Storage System (BESS) increased. The BESS can be used for various purposes such like frequency response, load leveling, and fluctuation mitigation of renewable energy generators. In this paper, three state BESS model is proposed. the BESS model considering charge, discharge and keeping efficiency, and life cycle according to depth of discharge (DOD). Then, the benefit and cost of BESS installed at substation for load leveling are summarized. The economic evaluation of BESS is analyzed using net present values (NPV) analysis. In case study, the NPV analysis of NaS battery system is carried out using the proposed BESS model. Because the result of economic evaluation of BESS using nowadays cost data is not positive, the sensitivity analysis of BESS is conducted by changing the capital cost and energy cost.

• 환경정책연구
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• 제2권2호
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• pp.81-103
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• 2003

This paper compares the environmental economic performance of the South Korean and the German economy during the last decade. The analysis is based on comparable data from the Environmental Economic Accounts (EEA). The EEA is a satellite account to the National Accounts which enhances the conventional economic accounts by a description of the interactions between the economy and the environment. The data from the EEA and the national accounts are fully compatible. In absolute terms the environmental pressures caused by economic activities were with regards to the environmental factors used for the analysis generally lower in South Korea than in Germany. If the use of environmental factors is related to each country's gross domestic product (environmental productivities) a lower level of environmental productivity can be observed for most of the environmental factors in South Korea compared to Germany. For example in 1999 energy and $CO_2$ productivity were about two fifths of the German level. This corresponds to the relation regarding labour productivity (Gross domestic product per employment).