• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.6
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• pp.259-264
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• 2006

This paper addresses the collusive bidding that functions as a potential obstacle to a fully competitive wholesale electricity market. Cooperative game is formulated and the equation of its Nash Equilibrium (NE) is derived on the basis of the supply function model. Gencos' willingness to selectively collude is expressed through a bargain theory. A Collusion Incentive Index(CII) for representing the willingness is defined through computing the Gencos' profits at NE. In order to keep the market non-cooperative, the market operator has to know the highest potentially collusive combination among the Gencos. Another index, which will be called the Collusion Monitoring Index(CMI), is suggested to detect the highest potential collusion and it is calculated using the marginal cost functions of the Gencos without any computation of NE. The effectiveness of CMI for detecting the highest potential collusion is verified through application on many test market cases.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.10
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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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.7
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• pp.1226-1231
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• 2010

This paper looks at the influence of Financial Transmission Rights (FTRs) on the market value(Social Welfare; SW) in the competitive electricity market. The transmission line constraints make it difficult to compute the Nash Equilibrium (NE) due to causing a mixed strategy NE instead of a pure strategy NE. Computing a mixed strategy is more complicated in a multi-player game. The aim of this paper are to compute a mixed strategy NE and analyze SW in power transaction with FTRs. This paper introduces a formula and a technique for solving NE of multi-player game with FTRs. In addition, it analyzes the influence of holding of FTRs by generation company on SW and it proposes the SW at NE is influenced by Power Transfer Distribution Factor (PTDF) where holder of FTRs are located. The assertion is verified by calculating the mixed strategy utilizing the Cournot model widely used for studies on FTRs.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.8
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• pp.403-408
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• 2002

As the electricity industry undergoes a process of fundamental restructuring, horizontal market power appears as a potential obstacle to a fully competitive wholesale electricity market. Market power is the ability profitably to maintain prices above competitive levels by restricting output below competitive levels. In models for imperfect competition under the consideration of the transmission constraints, the Nash equilibrium has the form of a mixed strategy. In this paper, the models for analyzing imperfect competition are compared using the solution of pure and mixed equilibria. The relation between market power and the capacity of a transmission line is investigated by imperfect competition analysis methods: Cournot, Bertrand, and Supply Curve model.

• The Korean Journal of Financial Management
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• v.12 no.1
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• pp.145-165
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• 1995

This paper studies a partial coordination situation where a set of countries coordinate their monetary policies among themselves;while the rest of the world choose their policies independently. Using a three-country orewlapping generations model, it is shown that nash partial-coordination equilibrium does not exist. This paper also studies the partial coordination under unanticipated productivity shocks.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1B
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• pp.1-7
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• 2012

Quasi-two dimensional numerical model (GSTARS) was applied to determine the optimal sediment discharge formula for simulating the sedimentologic characteristics of Hyeongsan river. The field measurements have been conducted to obtain the data, such as sediment discharge, bed material, and channel geometry, for model calibration and verification. The sediment discharge formulas, which have been generally used, have been assessed according to the average error, relative error, RMSE, RRMSE, discrepancy ratio and Nash-Sutcliffe efficiency coefficient for bed changes along the thalweg. From the results, Laursen formula(1958) shows the best performance to simulate the long-term bed change of Hyeongsan river.

• Industrial Engineering and Management Systems
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• v.8 no.4
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• pp.221-227
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• 2009

There are customer services jointly provided by two facilities so that each customer will complete the course made up of both facilities' sub-services. The two facilities are assumed invested respectively by an infrastructure owner and one subordinate facility owner, whose partnership is built on their capital investments. This paper presents a mathematical model of Stackelberg competition between the two facility owners to derive their optimal Nash equilibrium. In this study, each facility owner's profit is consisted of fixed revenue fractions of sold services, operating costs (including depreciation cost) and maintenance costs of her facility. The maintenance costs of one facility are incurred both by failures and deterioration due to usage. Moreover, for both facilities, failures are rectified immediately by minimal repairs and preventive maintenance is carried out at a fixed time epoch. Additional assumptions are also employed to develop the model such as customer arrivals are manipulated to follow a Poisson process, and each facility's lifetime is independently Weibull-distributed. The Stackelberg game proceeds as follows. At the first stage of decision making process, the infrastructure owner (acting as a leader) decides the allocation of revenue shares based on her self-interest. After observing the allocation of revenue shares, the subordinate facility owner determines her own optimal price of services. This paper investigates actions and reactions of the two partners in the system. Then analytical conditions are proposed to achieve a unique optimal Nash equilibrium. Finally, some suggestions for further research are discussed.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.3
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• pp.162-169
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• 2018

Net neutrality, which has not been a problem, has recently become a problem for ISPs (Internet Service Providers), and their complaints have been paid by domestic platform companies, but overseas global IT companies such as Google and YouTube, generate huge revenues from domestic markets. In this situation, domestic IT companies claim that it is natural to impose more expensive charges or restrict speed on users who generate huge traffic. On the other side, however, the telecommunication network has become an essential public good that is essential to our everyday life, and because it has been given a monopoly position by a private company to efficiently respond to the explosive demand for telecommunication services, It is necessary to provide equal and universal service and fulfill public duty. In this paper, we deal with the network neutrality problem, focusing on the price elasticity between the CP (Contents Provider) and the ISP, rather than the user who is one side of the two-sided market for the already saturated satellites communication market. We present a game model that determines the optimal price for each platform by Nash equilibrium and analyze how the net neutrality affects CP according to the change of exogenous variables through the proposed game model.

• Korea Trade Review
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• v.43 no.6
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• pp.1-24
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• 2018

This study analyzes the dispute settlement of between arbitration and litigation using a game theoretical approach. Many studies on arbitration have so far focused on the relevant institutions. However, there are few theoretical studies that have focused on the demand side of arbitration. The model presented here suggests conditions under which arbitration form a perfect Bayesian Nash equilibrium, provided that the players strategically choose a dispute settlement tool. Furthermore, the suggested model is used to analyze simple cases of international commercial dispute cases.

• Journal of Korea Water Resources Association
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• v.40 no.8
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• pp.617-628
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• 2007

The purpose of this paper is to prepare snowmelt parameters using RS and GIS and to assess the snowmelt impact in SLURP (Semi-distributed Land Use-based Runoff Process) model for Chungju-Dam watershed $(6,661.5km^2)$. Three sets of NOAA AVHRR images (1998-1999, 2000-2001, 2001-2002) were analyzed to prepare snow-related data of the model during winter period. Snow cover areas were extracted using 1, 3 and 4 channels, and the snow depth was spatially interpolated using snowfall data of ground meteorological stations. With the snowmelt parameters, DEM (Digital Elevation Model), land cover, NDVI (Normalized Difference Vegetation Index) and weather data, the model was calibrated for 3 years (1998, 2000, 2001), and verified for 1 year (1999) using the calibrated parameters. The average Nash-Sutcliffe efficiencies for 4 years (1998-2001) discharge comparison with and without snowmelt parameters were 0.76 and 0.73 for the full period, and 0.57 and 0.19 for the period of January to May. The results showed that the spatially prepared snow-related data reduced the calibration effort and enhanced the model results.