• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 A
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• pp.389-391
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• 2002

This paper presents the System Marginal Price(SMp) forecasting implementation using backpropagation Neural Networks in Competitive Electricity Market. SMP is very important term to seek the maximum profit to bidding participants. Demand and SMP that necessary data for training Neural Networks, supplied from Korea Power Exchange(KPX). Statistic analysis about predicted SMP presents a part of consideration in end of this paper.

• Journal of Dairy Science and Biotechnology
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• 제23권1호
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• pp.39-47
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• 2005

This paper is intended to estimate demand for milk using POS data. POS databases were taken from various retail store across the country that account for 5 percent. Own price elasticities are negative and most milk products are statistically significant. Advertising effects are marginal, and statistically significant except flavored milk. Seasonality is apparent from July through september except children's milk.

• 대한치과보철학회지
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• 제44권1호
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• pp.20-28
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• 2006

Statement of problem: The titanium has advantages of a high biocompatibility, a corrosion resistence, low density, and cheep price, so it is focused as a substituted alloy But it is quite difficult to cast with the tranditional method due to the high melting point, reacivity with element at, elevated temperature. By using the CAD-CAM system for the crown construction, it is possible to reduce the errors while proceeding the wax-up, investing, and casting procedure Purpose: The purposes of this study were to measure the marginal adaptation of the casting titanium coping and machine-milled titanium coping according to the casting methods and the marginal configurations. Material and method: The marginal configurations were used chamfer shoulder, and beveled shoulder. The total 30 copings were used, and these are divided into 6 groups according to the manufacturing method and marginal configuration. The gap between margin of the model and the restoration was measured with 3-dimensional measuring microscope. Results: The following results were obtained; 1. casting gold coping demonstrated the best marginal seal, followed by casting titanium coping finally machine-milled titanium copings. 2. In casting titanium coping, chamfer demonstrated the best marginal seal, followed by shoulder and beveled shoulder. There was no significantly difference in shoulder and beveled shoulder. But all margin form has clinically acceptable 3. In machine-milled titanium copings, chamfer demonstrated the best marginal seal, followed by shoulder and beveled shoulder. Beveled shoulder show large and uneven marginal gap Conclusions: Above result revealed that marginal adaptation of the titanim coping is avail able in the clinical range, it can be used as an alternative metal and it is prefered especially in chamfer or shoulder margin during implant superstructure fabrication. But there should be more research on machine-milled titanium in order to use it in the clinics.

• 자원ㆍ환경경제연구
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• 제19권1호
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• pp.3-21
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• 2010

발전부문의 부분적인 민영화 이후 전력의 도매가격은 한계가격(system marginal price)으로 결정되고, 이 가격은 발전사의 발전량에 의해서 달라지기 때문에 발전사 입장에서는 완전히 외생적으로 결정되는 가격이라 보기 어렵다. 본고는 Harrison(1994), Levinsohn(1993) 등이 개발한 시장의 완전경쟁성이 유지되지 않을 때에도 기업의 생산성 변화와 규모수익성, 마크업률 등을 분석할 수 있는 모형을 한국의 화력발전소 자료에 적용하였다. 분석결과 규모수익은 거의 없으며, 마크업률은 발전소의 사용 에너지 유형에 따라 크게 다른 것으로 나타났다. 아울러 완전경쟁시장을 가정하는 통상적인 분석법에 비해 발전소의 생산성 변화율 계측치도 상당한 정도 차이를 보였다.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.109-117
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• 2015

This paper proposes the comparison results of various optimal power flow algorithms (OPF) to calculate the locational marginal prices (LMP) of the unreduced full scale Korean transmission system. Five different types of optimal power flow models are employed: Full AC OPF, Cubic AC OPF, Quadratic AC OPF, Linear AC OPF and DC OPF. As the results, full AC OPF and cubic AC OPF model provides LMP calculation results very similar to each other while the calculation time of cubic AC OPF model is faster than that of the Full AC OPF. Other simplified OPF models, quadratic AC OPF, linear AC OPF and DC OPF offer erroneous results even though the calculation times are much faster than the Full AC OPF and the Cubic AC OPF. Given the condition that the OPF models sometimes fail to find the optimal solution due to the severe complexity of the Korean transmission power system, the Full AC OPF should be used as the primary OPF model while the Cubic AC OPF can be a promising backup OPF model for the LMP calculations and/or real-time operation.

• 신재생에너지
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• 제10권1호
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• pp.41-49
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• 2014

For a proper valuation of wind power project, it is necessary to consider volatilities of key parameters such as annual energy production, electricity sales price, and long term interest rate. Real option methodology allows to calculate option values of these parameters. Volatilities to be considered in wind project valuation are 1) annual energy production (AEP) estimation due to meteorological variation and estimation errors in wind speed distribution, 2) changes in system marginal price (SMP), and 3) interest rate fluctuation of project financing which provides refinancing option to be exercised during a loan tenor for commercial scale projects. Real option valuation turns out to be more than half of the sales value based on a case study for a FIT scheme wind project that was sold to a financial investor.

• 농업과학연구
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• 제22권1호
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• pp.110-126
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• 1995

Korean economy has been developed successfully in the course of implementing the five year economic development plans since 1962. The gap of incomes and quality of life between rural and urban area has been widened and it made rural farm laborers drain to urban areas. Therefore the prevailing situation of labor shortage and wage hike in rural area has made farm management deteriorate in recent years. Under the internal and international unfavorable economic conditions, marginal farm land of 66.5 thousand ha has been idled as of end of 1993. The total area outside agricultural development zone with bad farming conditions including irrigation and drainage, and land consolidation for mechanization were estimated at 360.4thousand ha equivalent to 17.5% of the total farm land area in Korea. Considering the topographical conditions of marginal lands, the effective use of marginal lands should be studied from the view point of public interest rather than from the view point of individual economic conditions. Considering the present agricultural economic settings, such as price decrease, unfavourable benefits of farm products, labour shrotage, free trade of farm products and poor physical condition of marginal lands, the institutional and realistical measures for the effective utilization of idle and marginal land should be studied as soon as possible. Detail land use pattern should be surveyed in the areas outside agricultural development zone and have to be classified as orchard farms, grass land, fish culture farms, lawn and ornamental tree farm, sight seeing and leisure farms for urban peoples, special crops production farms and common farms to be developed for farm mechanization. According to the surveyed results, the expected utilization patterns of the idle and marginal lands could be considerd as village common use, farm land base development, leisure farm development, mutual complementary utilization between urban and rural areas, G't purchase and management, credit supply and new extension services, improvement of cropping patterns and sight seeing and leisure farm patterns. For the successful and reasonable management of the marginal lands, the actions such as institutional improvement, prohibition of idle marginal land, enforcement of activities of farm management committee members and land banking system of RDC including development and utilization systems should be included.

• Journal of Electrical Engineering and Technology
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• 제5권4호
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• pp.530-537
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• 2010

By development of renewable energy and more efficient facilities in an increasingly deregulated electricity market, the operation cost of distributed generation (DG) is becoming more competitive. International environmental regulations of the leaking carbon become effective to reinforce global efforts for a low-carbon paradigm. Through increased DG, operators of DG are able to supply electric power to customers who are connected directly to DG as well as loads that are connected to entire network. In this situation, a community energy system (CES) with DGs is a new participant in the energy market. DG's purchase price from the market is different from the DG's sales price to the market due to transmission service charges and other costs. Therefore, CES who owns DGs has to control the produced electric power per hourly period in order to maximize profit. Considering the international environment regulations, CE will be an important element to decide the marginal cost of generators as well as the classified fuel unit cost and unit's efficiency. This paper introduces the optimal operation of CES's DG connected to the distribution network considering CE. The purpose of optimization is to maximize the profit of CES. A Particle Swarm Optimization (PSO) will be used to solve this complicated problem. The optimal operation of DG represented in this paper would guide CES and system operators in determining the decision making criteria.

• 자원ㆍ환경경제연구
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• 제23권4호
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• pp.719-746
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• 2014

본 연구는 수질오염물질에 대한 가상적 배출권거래시장을 상정하여 균형배출권가격을 도출함으로써 수질개선에 따른 편익을 추정하려고 시도하였다. 우리나라에서는 낙동강수계를 비롯하여 주요 수계에 수질오염물질 총량관리제도가 실시되고 있다. 사회적으로 바람직스러운 배출총량을 결정함으로써 국민과 정부는 암묵적으로 수질오염물질의 경제적 가치를 결정한 것과 같다고 할 수 있다. 각 지자체별로 수질오염물질 배출상의 제약으로 인하여 희생된 경제적 기회비용이 발생할 것이며 이 기회비용의 크기가 수질오염물질의 경제적 가치이기 때문이다. 이 가상적 배출권거래시장에서의 균형가격을 수질 총량제하의 수계전체의 배출총량과 지자체별 할당에 의하여 암묵적으로 결정된 수질오염물질 배출의 단위당 가치라고 해석할 수 있다. 배출량과 편익의 관계로부터 한계순편익함수를 도출하고 지자체별 배출허용총량을 이용하여 개별배출권 초과수요함수를 구성하여 균형배출권가격을 도출하였다. 추정 결과 배출권시장의 균형배출권가격이 1,409.3원/$kg{\cdot}BOD$으로 추산되었다. 이는 외국의 사례와 비교하여 적정한 수준이라 평가되며 이러한 배출권가격은 수질 오염물질의 단위당 경제적 가치를 산정하여 수질변화를 수반하는 사업의 B/C분석에 직접적으로 이용할 수 있을 것으로 기대된다.

• 전기학회논문지
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• 제63권7호
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• pp.889-895
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• 2014

Korea electric power industry had been under vertical monopoly but is typically getting restructured for free competition. An ideal pricing system under the competitive market system is 'unbundled pricing system' and 'marginal pricing system', but the current pricing system still adheres to the traditional bundled system and the average cost pricing system. Especially, progressive electricity rates for residential use reflect governmental policy-making which is focused on income redistribution & welfare, industrial supports and energy saving. This study proposes new and reasonable residential electricity pricing systems which are Time-Of-Use (TOU) and Real-Time Pricing (RTP) to reflect variations in the wholesale price of electricity. It also presents examples of various tariffs for residential electricity pricing systems.