• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
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• pp.181-183
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• 1999

As one of ancillary services, voltage support and reactive power service should be compensed properly for its contribution. In this paper, a cost-based reactive power planning is presented. which minimizes the total cost of reactive power support of generators and VAR compensation facility installation. Reactive power support of generator is evaluated by the opportunity costs of reduced energy sale considering the varying SMP(system marginal price) in power market, Gradient projection method is applied to solve this reactive power planning using IEEE14 bus system.

• The Journal of Asian Finance, Economics and Business
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• 제9권1호
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• pp.153-166
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• 2022

The study estimates the Structured VAR and the Dynamic Stochastic General Equilibrium Model for the Vietnamese economy based on the new Keynesian model for small and open economies, with the output gap, inflation, policy interest rate, the Vietnamese exchange rate, and the inflation and interest rate in the United States. The paper aims to clarify the impulse response of the macro variables through their shocks. It offers to model the SVAR and DSGE processes, as well as describe why and how interest rate policy is important in the impulse response of macro variables like the output gap and inflation process. The study supports the central role of monetary policy by giving empirical evidence for the new Keynesian theory, according to which an interest rate shock causes the output gap to widen and inflation to decrease. Finally, the application of the DSGE model is becoming more and more popular in the State Bank of Viet Nam to improve its policy planning, analyzing, and forecasting policy towards sustainable and stable growth.

• 한국산학기술학회논문지
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• 제16권9호
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• pp.6315-6324
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• 2015

본 연구에서는 2008년 금융위기 이후 부동산 정책에서 많은 비중을 차지하는 서울의 아파트 전세가격에 가계경제가 어떤 영향을 미치는지 2009년 1월부터 2013년 12월까지 자료를 이용하여 VAR모형을 통해 실증분석하였다. 서울의 전세가격에 미치는 가계경제변수들은 서울 아파트 매매가격, 소비자물가지수, 고용률, 실질GNI, 가계대출금액으로 구성하였다. 분석결과에 따르면, 서울 아파트 전세가격은 단기적으로 가계경제변수들에 영향력을 받는 것으로 나타났다. 또한 가계경제변수들의 구조적 충격에 따른 서울 아파트 전세가격 변동의 상대적 기여도는 단기적으로는 서울 아파트 전세가격 자체 충격에 가장 큰 영향력을 받으며, 시간이 지날수록 가계변수들의 영향력이 커지는 것으로 나타났다. 본 연구결과를 통해 가계경제를 이루는 어떤 요인들이 주택전세가격에 많은 영향을 미치는지 파악할 수 있어 향후 주택가격 안정화를 위한 정책수립에 기여할 것으로 기대된다.

• 한국컴퓨터산업학회논문지
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• 제2권8호
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• pp.1069-1074
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• 2001

본 논문에서는 퍼지수리계획법에 의한 최적화 문제의 해 분석에 ASP(Active Server Page)를 적용한 알고리즘을 제시하였다. 수리문제에서 목적함수의 목표와 제약조건의 만족도레벨의 애매성을 다루는데 있어서 퍼지 이론은 강력한 도구가 되고 있다. 제시한 알고리즘은 IEEE-30모선 시스템을 이용하여 유효성을 검증하였다.

• 한국환경복원기술학회지
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• 제18권3호
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• pp.1-11
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• 2015

This research was conducted to compare the effect of soil amendment and loess on physial and chemical properties of dredged soil and primary height growth of Ulmus davidiana var. japonica. Three types of research plots: control plot (Dredged soil only), DC treatment plot (Dredged soil + soil amendment) and DCL treatment plot (Dredged soil + soil amendment + Loess) were set at Okgu research site in Saemanguem. 32 trees of U. davidiana var. japonica were planted in each plots after 14 months from the construction. Soil texture, pH, electrical conductivity (EC), organic matter (OM), total nitrogen (TN), available P, exchangeable cation ($K^+$, $Na^+$, $Mg^{2+}$, $Ca^{2+}$) and sodium chloride were measured after 3 years from the construction. Also, survival rate and height of U. davidiana var. japonica were measured 22 months after planting, and the correlation between height of trees and the physico-chemical properties of soil were analyzed. Even though pH in both DC and DCL treatment plots are lower than control plot, they are still alkaline (> pH 8). OM, TN and available P in both DC and DCL treatment were higher than the control. Particularly, the content of available P in both DC and DCL treatment plots are 1.4~5.1 times and 2.0~3.1 times higher than the control respectively. The concentration of exchangeable Mg in DCL treatment plot was 1.1~5.5 times higher than the control (p < .05). The survival rate of the species was the highest in DCL treatment plot (98%) followed by DC treatment plot and the control. The average height of the trees in both DC and DCL treatment plots is 1.1m while the control is 0.8m. OM, TN, available P, K+ were significantly related to the height of U. davidiana var. japonica(p < .01). The results indicate that soil amendment affects on soil physial and chemical properties of dredged soil and height growth of U. davidiana var. japonica.

• 한국환경복원기술학회지
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• 제14권6호
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• pp.29-39
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• 2011

This study aimed to select evergreen broad-leaved trees (EBT) that can be produced and planted in Korea by analyzing the current use of the trees for landscaping in the Kyushu area of Japan, a warm temperate region. The results revealed the total production of EBT was higher than that of conifers and due to the suitable growth environment of the area and the subsequent high demand for them. The landscape tree production methods in Japan were divided into container nursery and outdoor nursery, and the uses and species of the trees varied depending on the method; a variety of native species were produced in container nursery rather than in outdoor nursery, whereas trees used as ornamental, gardening, and shade plants were produced in outdoor nursery rather than in container nursery. The results also showed that in Fukuoka, a major city in Kyushu that is adjacent to Korea, the planting rate of EBT, used as ornamental, gardening, and shade plants, was higher than that of deciduous broad-leaved trees and conifers. In the city, the planting rate of Cinnamomum camphora was the highest, Elaeocarpus sylvestris var. ellipticus, Ternstroemia gymnanthera, Ilex rotunda, Quercus glauca, Camellia sasanqua, Eurya emarginata, Pittosporum tobira, Raphiolepis indica var. umbellata, Hedera rhombea, Kadsura japonica, Trachelospermum asiaticum var. asiaticum. These species were verified in Kyushu area for their application as landscape trees and are expected to serve as landscape trees in Korea if the planting areas of them are expanded by global warming, urban heat island and regional microclimate.

• 한국환경생태학회지
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• 제25권3호
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• pp.267-283
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• 2011

내장산국립공원지역에서 확인된 환경부 지정 멸종위기종은 진노랑상사화, 노랑붓꽃, 대흥란 및 백운란 4분류군이었으며, 식물구계학적 특정식물종은 총 159분류군으로 I 등급에 해당하는 분류군은 옥녀꽃대, 가는갈퀴나물 및 말오줌때등으로 91분류군, II 등급에 해당하는 분류군은 참개별꽃, 퍼진고사리 및 토끼고사리 등으로 17분류군, III 등급에 해당하는 분류군은 고려엉겅퀴, 어리병풍 및 솜분취 등으로 32분류군, IV 등급에 꼬리말발도리, 갈사초 및 측백나무 등으로 9분류군, V 등급에 백양더부살이, 진노랑상사화 및 백양꽃 등으로 10분류군이 확인되었다. 한국고유생물종은 애기닥나무, 참개별꽃 및 가는장구채 등으로 총 40분류군이 확인되었다. 굴거리나무림(제 91호)와 비자나무림(제 153호)이 천연기념물로 지정되어 보호되고 있다. 귀화식물은 닭의덩굴, 털여뀌 및 소리쟁이 등으로 30분류군이 확인되었고, 생태계교란야생식물은 나타나지 않았다.

• Journal of Electrical Engineering and Technology
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• 제4권1호
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• pp.55-65
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• 2009

Due to the rapid increase of electricity demand, consideration of environmental constraints in optimal power flow (OPF) problems is increasingly important. In Algeria, up to 90% of electricity is produced by thermal generators (vapor, gas). In order to keep the emission of gaseous pollutants like sulfur dioxide (SO2) and Nitrogen (NO2) under the admissible ecological limits, many conventional and global optimization methods have been proposed to study the trade-off relation between fuel cost and emissions. This paper presents an efficient decomposed Parallel GA to solve the multi-objective environmental/economic dispatch problem. At the decomposed stage the length of the original chromosome is reduced successively and adapted to the topology of the new partition. Two subproblems are proposed: the first subproblem is related to the active power planning to minimize the total fuel cost, and the second subproblem is a reactive power planning design based in practical rules to make fine corrections to the voltage deviation and reactive power violation using a specified number of shunt dynamic compensators named Static Var Compensators (SVC). To validate the robustness of the proposed approach, the algorithm proposed was tested on the Algerian 59-bus network test and compared with conventional methods and with global optimization methods (GA, FGA, and ACO). The results show that the approach proposed can converge to the near solution and obtain a competitive solution at a critical situation and within a reasonable time.

• Journal of Electrical Engineering and Technology
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• 제6권6호
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• pp.786-792
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• 2011

The present paper presents an optimal capacitor placement (OCP) algorithm for voltagestability enhancement. The OCP issue is represented using a mixed-integer problem and a highly nonlinear problem. The hybrid particle swarm optimization (HPSO) algorithm is proposed to solve the OCP problem. The HPSO algorithm combines the optimal power flow (OPF) with the primal-dual interior-point method (PDIPM) and ordinary PSO. It takes advantage of the global search ability of PSO and the very fast simulation running time of the OPF algorithm with PDIPM. In addition, OPF gives intelligence to PSO through the information provided by the dual variable of the OPF. Numerical results illustrate that the HPSO algorithm can improve the accuracy and reduce the simulation running time. Test results evaluated with the three-bus, New England 39-bus, and Korea Electric Power Corporation systems show the applicability of the proposed algorithm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.273-275
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• 1998

This paper presents a method of determining the minimum amount of reactive power capacity installation and minimizing transmission line losses. It deals with maintaining voltage profile within an acceptable range with respect to the increase in load demand. Our approach provides three-different stages to power system planner. First stage considers existing capacitors. Second stage considers expanding the size of the installed capacitors. Third stage considers existing capacitors and newly installed capacitors whose locations are irrelevant to the locations of existing ones. Validity and effectiveness of the proposed algorithm are confirmed by results on modified New England 30 bus test system.