• 대한전기학회논문지:전력기술부문A
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• 제51권4호
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• pp.196-201
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• 2002

An important aspect of the study of power system markets involves the assessment of strategic behavior of participants for maximizing their profits. In models for imperfect competition of a deregulated system, the key tack is to find the Nash equilibrium. When the constraints are not considered in the power market, the equilibrium has the form of a pure strategy. However, the constraints are considered, the equilibrium has the form of a mired strategy. In this paper the bimatrix game approach leer finding a mixed equilibrium is analyzed. The Nash equilibrium of a mixed strategy will be used adequately for the analysis of market power.

• 대한전기학회논문지:전력기술부문A
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• 제54권2호
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• pp.79-87
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• 2005

At present Cournot model is one of the most commonly used theories to analyze the gaming situation in oligopoly market. But there exist several problems to apply this model to electricity market. The representative one is to obtain the inverse demand curve able to be induced from the relationship between market price and demand response. In Cournot model, each player offers their generation quantity to accomplish maximum profit, which is accomplished by reducing their quantity compared with available total capacity. As stated above, to obtain the probable Cournot equilibrium to reflect real market situation, we have to induce the correct demand function first of all. Usually the correlation between price and demand appears on the long-term basis through the statistical data analysis (for example, regression analysis) or by investigating consumer utility functions of several consumer groups classified as residential, industrial, and commercial. However, the elasticity has a tendency to change continuously according to the total market demand size or the level of market price. Therefore it should be updated as trading period passes by. In this paper we propose a method for inducing and updating this price elasticity of demand function for more realistic market equilibrium.

• 한국경영과학회지
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• 제35권4호
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• pp.55-79
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• 2010

This study deals with a model for platform competition in a two-sided market. We suppose there are both direct and indirect network externalities between suppliers and users of each platform. Moreover, we suppose that both users and suppliers are distributed in their relative affinity for each platform type. That is, each user [supplier] has his/her own preferential position toward each platform, and users [suppliers] are horizontally differentiated over [0, 1]. And for analytical tractability, some parameters like direct and indirect network externalities are the same across the markets. Given the parameters and the pricing profile, users and suppliers conduct subscription game, where participants select the platform that gives them the highest payoffs. This game proceeds according to a replicator dynamics of the evolutionary game, which is simplified by properly defining gains from participant's strategy in the subscription game. We find that depending on the strength of these network effects, there might either be multiple stable equilibria, at which users and suppliers distribute across both platforms, or one unstable interior equilibrium corresponding to the market tipping in favor of either platform. In both cases, we also consider the pricing power of competing platform providers under the framework of the Stackelberg game. In particular, our study examines the possible effects of the type of competition between platform providers, which may constrain the equilibrium selection in the subscription game.

• 대한전기학회논문지:전력기술부문A
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• 제55권10호
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• pp.440-445
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• 2006

As an electricity industry transforms into a competitive system, an electricity market revolves into a combined market consisting of generation and operating reserve. This paper presents a market model combined by an energy market and an operating reserve market. In a competitive structure, Gencos strive to choose strategic bidding parameters that maximize total profit resulting from an energy market and a reserve market. The primary goal of the paper is to analyze power transactions of generation and operation reserve based on marginal profits and capacity limits at NE(Nash Equilibrium). In case studies, the reserve market and the energy market are compared at the n from the viewpoints of marginal profits, prices and transaction quantities. It is shown that the marginal profit in an energy market is equal to that in a reserve market, and Gencos strategic bidding is greatly influenced by capacity limit.

• 대한산업공학회지
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• 제27권2호
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• pp.181-189
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• 2001

The proliferation of the Internet and related technologies and applications has led to a new form of market place known as the electronic store. In this paper, we study competition between two shopping channels, an electronic store and traditional retailers. Based on the circular spatial market model, we derive the Nash and Stackelberg equilibria as a function of the efficiency of the electronic store. The result shows that the Stackelberg equilibrium is always superior to the Nash equilibrium for both channels. It is also shown that, in some cases, the electronic store has incentive to decrease its efficiency to gain more profit.

• 대한전기학회논문지:전력기술부문A
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• 제52권10호
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• pp.616-623
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• 2003

Competition among electric generation companies is a major goal of restructuring in the electricity industry, The trading system in an electricity market has been one of the most important issues in deregulated electricity market. This paper deals with comparisons of the major two types of the trading system: compulsory pool market and bilateral contract market. The two trading systems are compared quantitatively from the viewpoint of consumer's surplus and social welfare, This paper, also, proposes a unified model of Cournot and Bertrand for analyzing the mixed trading system of pool market and bilateral contract market. Nash equilibrium of the unified model is derived by criteria for participating in bilateral contract market. Numerical results from a sample case show that a mixed trading system of pool market and price-competitive bilateral market is beneficial to consumer from the view points of consumer's surplus.

• KIEE International Transactions on Power Engineering
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• 제5A권4호
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• pp.396-402
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• 2005

In an electricity market with imperfect competition, participants devise bidding plans and transaction strategies to maximize their own profits. The market price and the quantity are concerned with the operation reserve as well as the bidding system and demand curves in an electricity market. This paper presents a market model combined by an energy market and an operating reserve market. The competition of the generation producers in the combined market is formulated as a gaming of selecting bid parameters such as intersections and slopes in bid functions. The Nash Equilibrium (NE) is analyzed by using bi-level optimization; maximization of Social Welfare (SW) and maximization of the producers' profits.

• 전기학회논문지
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• 제61권2호
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• pp.187-193
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• 2012

Nash Equilibrium (NE) is as useful tool for investigating a participant's strategic generation quantity in a competitive electricity market. Cournot model may give a mixed strategy NE instead of a pure strategy when transmission constraints are considered. A mixed strategy is difficult to compute, complicated to understand conceptually, and hard to implement in an electricity market practically. This paper presents that a mixed strategy does not appear in Stackelberg leader-follower model even under a transmission congestion. A solution method is proposed for the leader-follower model under a nondifferentiable space of a strategy variable. Based on the pure strategy NE with a transmission line congested, the merit of leader-follower model is shown from a social welfare point of view.

• 재무관리연구
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• 제25권3호
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• pp.111-130
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• 2008

이 논문은 분수공적분 개념을 이용하여 KOSPI200지수와 지수선물가격간에 장기균형관계가 있는지를 살펴보고 있다. 이것을 위해 로그변환 현 선물가격 각각의 분수차분계수를 주파수영역 (frequency domain)의 GPH 추정량을 구한 다음, 현 선물 회귀식의 추정을 통해 도출한 균형오차의 차분계수와 비교하였다. 이 방법은 전통적인 공적분방법에서 규명하지 못한 금융시계열자료의 통계적인 특성을 분석할 수 있는 장점이 있다. 분석결과를 요약하면 다음과 같다. 첫째, 정수차원의 차분구조모형에서는 공적분검정을 통한 장기균형관계의 증거를 찾기가 어려웠다. ADF 단위근 검정과 KPSS 정상성 검정에서 상반된 결과가 제시되어 두 시계열을 I(1)으로 확정하기가 불가능하였다. 둘째, GPH 추정량를 이용하여 차분계수를 추정한 결과, 두 시계열 모두 불안정한 장기기억구조를 가지는 것으로 식별되었고 균형오차는 정상적인(stationary) 장기기억구조를 가져 현 선물가격간에 분수공적분관계가 있는 것으로 파악되었다. 이 논문은 선물시장과 현물시장이 장기균형관계를 국내 선행연구에서 이용하지 않았던 분수공적분을 이용하여 분석했다는 점에서 그 의의를 찾을 수 있다.

• KIEE International Transactions on Power Engineering
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• 제3A권1호
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• pp.47-52
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• 2003

This paper presents a schematic process based on the method of eliminating dominated strategies to obtain the optimal bidding strategy Pursuing the Nash equilibrium Point. The Proposed approach is demonstrated for a bidding game in a generation competitive market with 2-dimensional bidding strategy vectors constituting a price-quantity strategy curve.