• Journal of Electrical Engineering and Technology
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• 제8권5호
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• pp.991-1001
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• 2013

Instead of building new substations or transmission lines, proper installation of flexible AC transmission systems (FACTS) devices can make the transmission networks accommodate more power transfers with less expansion cost. In this paper, the problem to maximize power system loadability by optimally installing two types of FACTS devices, namely static var compensator (SVC) and thyristor controlled series compensator (TCSC), is formulated as a mixed discrete-continuous nonlinear optimization problem (MDCP). To reduce the complexity of the problem, the locations suitable for SVC and TCSC installations are first investigated with tangent vector technique and real power flow performance index (PI) sensitivity factor and, with the specified locations for SVC and TCSC installations, a set of schemes is formed. For each scheme with the specific locations for SVC and TCSC installations, the MDCP is reduced to a continuous nonlinear optimization problem and the computing efficiency can be largely improved. Finally, to cope with the technical and economic concerns simultaneously, the scheme with the biggest utilization index value is recommended. The IEEE-14 bus system and a practical power system are used to validate the proposed method.

• 환경영향평가
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• 제31권6호
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• pp.438-448
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• 2022

본 연구는 공간계획 단계에서 생태적 건전성 향상을 유도할 수 있는 계획수단으로 환경생태계획 기법과 환경계획지표인 생태면적률의 정량적인 산정지표를 개선하기 위한 연구이다. 현재 운영 중인 공간유형 및 산정지표에 대해 상대적 중요도를 파악하고 공간유형 및 가중치의 개선에 대한 의견분석을 통해 대안을 찾고자 한다. 본 연구의 방법으로는 공간유형 및 산정지표의 심층분석을 위한 공간유형의 상대적 중요도 평가를 위한 AHP 분석을 실시하였다. 연구의 신뢰성과 객관성을 확보하기 위하여 전문가 50인이 참여하였다. 본 연구를 통해 생태면적률 유형별 한계점과 개선에 대한 의견분석을 통해 발전하는 기술과 공법, 유지관리 효율성, 경제성, 시공기술의 향상 등과 연계한 생태면적률 적용을 통해 도시환경의 개선과 생태면적률 활성화에 기여할 것으로 기대된다.

• 한국지진공학회논문집
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• 제10권6호
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• pp.47-56
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• 2006

지진응답 제어를 위하여 사장교 구조물에 장착된 준능동MR 댐퍼의 경제적 효율성 평가기법을 제안하였으며, 다양한 지반운동 특성에 대하여 비용효율성을 극대화하는 MR 댐퍼의 최적용량에 대한 분석을 수행하였다. MR 댐퍼의 비용효율성 평가를 위하여 생애주기비용 개념을 적용하였으며, 생애주기비용을 이루는 비용항목 중 손상비용의 기대값을 평가하기 위하여 지진재해로 인한 사장교의 파괴확률을 추정하였다. 사장교의 파괴로 인한 직 간접 손상비용의 규모를 매개변수로 하여 비용효율성을 평가하였다. 비용효율성 평가지수는 MR 댐퍼의 장착으로 인한 추가 투자비용과 사장교 구조물의 손상비용으로 이루어진 함수로서, 탄성받침이 사용된 기존의 설계에 대한 경제적 효율성을 나타내도록 정의하였다. 사장교의 지진응답 제어를 위하여 장착된 MR 댐퍼는 경제적으로 효율적인 대안인 것으로 나타났다. 지반운동의 특성과 손상비용 규모에 대한 MR 댐퍼의 최적 용량을 분석한 결과, 지진위험도 및 손상비용 규모가 커짐에 따라 가장 높은 비용효율성을 가지는 MR 댐퍼용량이 증가하는 것을 확인할 수 있었다.

• 설비공학논문집
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• 제19권10호
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• pp.695-702
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• 2007

In this paper, the ventilation efficiencies of an underground sewage disposal plant were investigated for ventilating system without fan, ventilating system with eleven cross flow fans and ventilating system with sixteen cross flow fans by numerical method. It has been found that the air change effectiveness of the system without fan was predicted 0.44. It means that an additional ventilating equipment is needed to maintain good indoor air quality. For the ventilating system with sixteen cross flow fans, the air change effectiveness was predicted 0.55. The air change effectiveness of the ventilating system with eleven cross flow fans was predicted 0.51. It is known that the air change effectiveness above 0.5 is enough to eliminate pollutant and bad smell in the indoor. Therefore, it is recommended to select the ventilating system with eleven cross flow fans for the underground sewage disposal plant in an economic point of view.

• The Journal of Asian Finance, Economics and Business
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• 제7권9호
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• pp.169-178
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• 2020

In this paper, we provide an overview of financial development in Vietnam. Particularly, a new approach of this study is to measure financial development through improvements in depth, efficiency and access of the banking system and stock market. Further, the study examines the factors significantly affecting financial development in Vietnam. The data are collected in Vietnam, an emerging country with a limited financial development. We employ the Autoregressive Distributed Lag (ARDL) approach, which generates a high reliability and suits data characteristics of emerging countries like Vietnam. We observe that Vietnam's banking system plays a key role in supplying credits to the economy while the nascent stock market at a limited size shows its potential for a considerable growth in the future. We also find the influential determinants of financial development in Vietnam including real estate market (RE), economic growth (EG), consumer price index (CPI), and global financial crisis (GFC). These findings are essential for Vietnamese authorities in providing practical solutions in order to build a sustainable and synchronous financial development. They are also first empirical evidence relating to an overview of financial development in an emerging country, so they are not only valuable to Vietnam but also crucial to other emerging economies.

• Journal of Ginseng Research
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• 제34권3호
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• pp.175-182
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• 2010

North American ginseng seedlings (Panax quinquefolius L.) were grown in pots in heated greenhouses, in a cool greenhouse, or in the field, in 11 experiments at various times over 16 years. Crop establishment, dry matter partitioning, photosynthesis, radiation use efficiency and carbon budget were measured and/or calculated in some years. Once the seedling canopy, of about $20\;cm^2$ per seedling, and a leaf area index of 0.37, was established, about 40 days after germination, full canopy display lasted about 87 days. Only 16.6% of the incoming solar radiation was intercepted by the crop, the remainder falling on the mulched soil surface. Total and root dry matter accumulations in the cool greenhouse and in the field were about double that in the heated greenhouses. Partitioning of dry matter to roots (economic yield or harvest index) in the cool greenhouse and in the field was 73% whereas it was 62.5% in the heated greenhouses. The relationship between root dry matter and radiation interception during the full canopy period was linear with growth efficiencies of $2.92\;mg\;MJ^{-1}$ at 4.8% of incoming radiation and $0.30\;mg\;MJ^{-1}$ at 68% of incoming radiation. A photosynthetic rate of $0.39\;g\;m^{-2}\;h^{-1}$ was attained at light saturation of about $150\;{\mu}mol\;m^{-2}\;s^{-1}$ (7.5% of full sunlight); dark respiration was $0.03\;g\;m^{-2}\;h^{-1}$, about 8.5% of maximum assimilation rate. Estimates of dry matter accumulation by growth analysis and by $CO_2$ uptake were similar, 6.21 vs. 7.62 mg $CO_2$, despite several assumptions in $CO_2$ uptake calculations.

• Asian Journal of Innovation and Policy
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• 제12권2호
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• pp.200-215
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• 2023

The purpose of this paper is to analyze the Korean government's investment priorities for the establishment of a supercomputer joint utilization system using AHP. The AHP model was designed as a two-layered structure consisting of two areas of specialized infrastructure, a one-stop joint utilization system service, and four evaluation items for detailed tasks. For the weight of each evaluation item, a cost efficiency index considering the annual budget was developed for the first time and applied to the weight calculation process. AHP analysis conducted a survey targeting supercomputer experts and derived priorities with 22 data that had completed reliability verification. As a result of the analysis, the government's investment priority was high in the order of dividing infrastructure for each Specialized Center and building resources in stages. In the future, the analysis results will be used to select economic promotion plans and prepare strategies for the establishment of the government's supercomputer joint utilization system.

• 농업과학연구
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• 제9권1호
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• pp.314-356
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• 1982

산란계(産卵鷄)의 주요(主要) 경제형질(經濟形質)의 효율적(效率的)인 개량(改良)을 위(爲)하여 지금까지는 체중(體重), 초산일령(初産日令), 산란계(産卵鷄) 및 난중(卵重)을 기초(基礎)로 하여 선발(選拔)하여 왔으나, 실제(實際) 가식부분(可食部分)은 난황(卵黃) 및 난백(卵白)이므로 이들에 대한 유전적(遺傳的) 모수(母數)를 추정(推定)하여 난황(卵黃) 및 난백(卵白)의 중량(重量)을 선발지수(選拔指數) 추정(推定)에 이용(利用)하므로서 선발(選拔)의 정확도(正確度)를 높일 수 있는 가능성(可能性)을 구명(究明)하기 위(爲)하여 본(本) 연구(硏究)를 실시(實施)하였다. 공시계(供試鷄)는 국립종축장(國立種畜場) 대전지장(大田支場)에서 폐쇄군(閉鎖郡) 육종방법(育種方法)에 의(依)해서 개량(改良)되어온 S. C. W. Leghorn종(種) 351수(首)와 R. I. Red종(種) 326수(首)가 사용(使用)되었고, 난구성분(卵構成分)은 총(總) 6,097개(個)가 조사(調査)되었으며, 각(各) 형질(形質)들은 1979년(年) 3월(月) 1일(日)부터 500일간(日間) 조사(調査) 분석(分析)되었다.

• 한국항만경제학회지
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• 제25권3호
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• pp.207-228
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• 2009

본 논문에서는 컨테이너터미널의 운영사 난립으로 부산항의 경쟁력이 저하되는 것을 회복시키기 위해 컨테이너 터미널 운영사를 어떻게 통합하는 것이 효율적인 것인가를 실증분석하였다. 세계 중요항만에 비하여 부산항이 운영사가 난립되어 있으며 운영규모도 영세하여 규모의 경제효과가 떨어지는 것으로 나타나고 있다. 시장집중도를 분석하는 지표인 상위 K개사의 기업집중률($CR_K$)과 허쉬만-허핀달 지수(HHI)를 이용하여 분석한 결과 규모의 경제효과를 얻기에는 매우 미흡한 운영규모로 나타나고 있다. 이러한 문제점을 해소하기 위해 터미널 운영사 통합방식을 대통합방식인 시나리오 Ⅰ과 소통합방식인 시나리오 Ⅱ에 대해서도$CR_K$와 허쉬만-허핀달 지수(HHI)를 도출한 결과 소통합방식인 시나리오 Ⅱ는 역시 규모경제효과를 얻기에는 미흡한 수준이고 대통합방식인 시나리오 Ⅰ는 적절한 규모로 평가되고 있다. 한편, 실제로 터미널을 운영 및 관리하는 운영사 임직원과 부산항만공사 임직원을 대상으로 정밀 설모조사에 의한 AHP분석한 결과에 의하면, 대통합방식인 시나리오 Ⅰ이 소통합방식인 시나리오 Ⅱ보다 가격경쟁력효과, 경영능력제고효과 그리고 생산성효과 모두 월등히 통합효과가 높은 것으로 나타나고 있다. 이러한 분석결과에 따르면, 부산항이 글로벌 항만으로서 동북아 물류네트워크의 허브가 되기 위해서는 하루속히 터미널운영사를 통합하여야 하는 것으로 나타나고 있다.

• 한국물환경학회지
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• 제38권5호
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• pp.240-246
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• 2022

Water and energy are inextricably linked and referred to as 'Water-Energy Nexus'. Recently, this topic has been drawing a lot of attention from various studies due to the exacerbated water availability. Korea's water and energy consumption has been increasing consistently, which calls for better management. This paper aims to identify changes in electricity consumption in relation to water intake and purification processes. Using Log Mean Divisia Index (LMDI) Decomposition Analysis method, this study attributes the changes to major factors such as; Total population (population effect), household/population (structure effect), GDP/household (economic effect), and water-related energy use/GDP (unit effect). The population effect, structure effect, and economic effect contributed to an increase in water-related electricity consumption, while the unit effect contributed to a decrease. As of 2019, the economic effect increased the water supply sector's electricity consumption by 534 GWh, the population effect increased by 73 GWh, and the structure effect increased by 243 GWh. In contrast, the unit effect decreased the electricity consumption by -461 GWh. We would like to make the following suggestions based on the findings of this study; first, the unit effect must be improved by increasing the energy efficiency of water intake and purification plants and installing renewable energy power generation facilities. Second, the structure effect is expected to increase over time, and to mitigate it, water consumption must be reduced through water conservation policies and the improvement of water facilities. Finally, the findings of this study are expected to be used as foundational data for integrated water and energy management.