• KIEE International Transactions on Power Engineering
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• v.5A no.1
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• pp.85-92
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• 2005

In this paper, Nash equilibriums of generation markets are investigated using a game theory application for simplified competitive electricity markets. We analyze the characteristics of equilibrium states in N-company spot markets modeled by uniform pricing auctions and propose a new method for obtaining Nash equilibriums of the auction. We assume that spot markets are operated as uniform pricing auctions and that each generation company submits its bids into the auction in the form of a seal-bid. Depending on the bids of generation companies, market demands are allocated to each company accordingly. The uniform pricing auction in this analysis can be formulated as a non-cooperative and static game in which generation companies correspond to players of the game. The coefficient of the bidding function of company-n is the strategy of player-n (company-n) and the payoff of player-n is defined as its profit from the uniform price auction. The solution of this game can be obtained using the concept of the non-cooperative equilibrium originating from the Nash idea. Based on the so called residual demand curve, we can derive the best response function of each generation company in the uniform pricing auction with N companies, analytically. Finally, we present an efficient means to obtain all the possible equilibrium set pairs and to examine their feasibilities as Nash equilibriums. A simple numerical example with three generation companies is demonstrated to illustrate the basic idea of the proposed methodology. From this, we can see the applicability of the proposed method to the real-world problem, even though further future analysis is required.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.7
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• pp.1299-1305
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• 2017

In this paper, we consider a beamforming game between the transmitters in a two-user multiple-input single-output interference channel using limited feedback and investigate how each transmitter is able to find a modified strategy from the quantized channel state information (CSI). In the beamforming game, each of the transmitters (i.e., a player) tries to maximize the achievable rate (i.e., a payoff function) via a proper beamforming strategy. In our case, each transmitter's beamforming strategy is represented by a linear combining factor between the maximum ratio transmission (MRT) and the zero forcing (ZF) beamforming vectors, which is the Pareto optimal achieving strategy. With the quantized CSI, the transmitters' strategies may not be valid because of the quantization errors. We propose a modified solution, which takes into account the effects of the quantization errors.

• Journal of the Korean Operations Research and Management Science Society
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• v.34 no.1
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• pp.1-10
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• 2009

Consumers earn a number of points for every purchase and then they can exchange a specified number of points for a desired reward in a typical loyalty program. The immediate payoff of their effort given as points is not the real reward they actually care about. It is merely an instrument (or medium) which has no value in itself. In a real world, consumers frequently choose the option with a bigger medium even though the economic value of the option is not changed by the medium. We call it 'medium effect.' In this study we explored if the size of medium affects consumers' preferences. For this we controlled the reward options with three types of medium (small, medium, big) and measured the magnitude of preference difference among the three types of reward options. In addition, we manipulated comparability of reward options with wine and gas discount coupon. We confirmed that choosing one of two wines was easier than that of the two gas coupons. 123 respondents were allocated into three experimental groups. In three experimental grounds, the ratios of the focused reward option's medium to the compared reward option's medium were different. For example, the focused reward option has 10 million points whereas the compared reward option has 10 million points for 1 million won purchase amount in the first group. Then each respondent was asked to choose one of two loyalty programs (focused program vs. compared program) in two different conditions (comparability between reward options. easiness vs. difficulty). To compare the medium effects among the experiment conditions we used chi-squares tests. The empirical results show consumer preference increases and then decreases as reward mile-ages/points given according to purchase amount increase. Additionally, they let us know that comparability of alter natives affects change of consumer preference by reward mileages/points.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2008.10a
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• pp.179-190
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• 2008

Consumers earn a number of points for every purchase and then they can exchange a specified number of points for a desired reward in a typical loyalty program. The immediate payoff of their effort given as points is not the real reward they actually care about. It is merely an instrument (or medium) which has no value in itself. In a real world, consumers frequently choose the option with a bigger medium even though the economic value of the option is not changed by the medium. We call it 'medium effect'. In this study we explored if the size of medium affects on consumers' preferences. For this we controlled the reward options with three types of medium (small, medium, big) and measured the magnitude of preference difference among the three types of reward options. In addition, we manipulated comparability of reward options with wine and gas discount coupon. We confirmed that choosing one of two wines was easier than that of the two gas coupons. 164 respondents were allocated into three experimental groups and one control group. In three experimental groups, the ratios of the focused reward option's medium to the compared reward option's medium were different. For example, the focused reward option has 10 million points whereas the compared reward option has 10 million points for 1 million won purchase amount in the first group. Then each respondent was asked to choose one of two loyalty programs (focused program vs. compared program) in two different conditions (comparability between reward options: easiness vs. difficulty). To compare the medium effects among the experiment conditions we used chi-squares tests. The empirical results show the medium effect increases and then decreases as the ratio of reward mileages/points to purchase amount increases. Additionally, they let us know that comparability of alternatives affects on the medium effects depending on the ratio of reward mileages/points to purchase amount.

• Communications for Statistical Applications and Methods
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• v.29 no.1
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• pp.85-101
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• 2022

Derivative-linked securities (DLS) is a type of derivatives that offer an agreed return when the underlying asset price moves within a specified range by the maturity date. The underlying assets of DLS are diverse such as interest rates, exchange rates, crude oil, or gold. A German 10-year bond rate-linked DLS and a USD-GBP CMS rate-linked DLS have recently become a social issue in Korea due to a huge loss to investors. In this regard, this paper accounts for the payoff structure of these products and evaluates their prices and fair coupon rates as well as risk measures such as Value-at-Risk (VaR) and Tail-Value-at-Risk (TVaR). We would like to examine how risky these products were and whether or not their coupon rates were appropriate. We use Hull-White Model as the stochastic model for the underlying assets and Monte Carlo (MC) methods to obtain numerical results. The no-arbitrage prices of the German 10-year bond rate-linked DLS and the USD-GBP CMS rate-linked DLS at the center of the social issue turned out to be 0.9662% and 0.9355% of the original investment, respectively. Considering that Korea government bond rate for 2018 is about 2%, these values are quite low. The fair coupon rates that make the prices of DLS equal to the original investment are computed as 4.76% for the German 10-year bond rate-linked DLS and 7% for the USD-GBP CMS rate-linked DLS. Their actual coupon rates were 1.4% and 3.5%. The 95% VaR and TVaR of the loss for German 10-year bond rate-linked DLS are 37.30% and 64.45%, and those of the loss for USD-GBP CMS rate-linked DLS are 73.98% and 87.43% of the initial investment. Summing up the numerical results obtained, we could see that the DLS products of our interest were indeed quite unfavorable to individual investors.

• Journal of Korea Trade
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• v.23 no.5
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• pp.118-128
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• 2019

Purpose - This paper examines the international R&D contest in which the extent of intellectual property right (IPR) affects both the size of prize for the winning firm and the extent of positive spillover through cost of firms. Recognizing the possibility of incomplete protection of IPR, the present paper analyzes the effect of changes in the extent of IPR on payoffs to firms and social welfare. Design/methodology - This paper examines coordination of IPRs by countries in economic integration. The paper then develops a general model of international R&D contest with incomplete protection of IPR. An increase in the extent of IPR augments the share of the prize the winning firm can appropriate, while decreasing the positive cost externality. To derive sharper results, the paper considers the cases of linear and fixed spillovers. Findings - Under plausible assumptions, an increase in the IPR augments the payoff to each firm and the aggregate payoffs as well. The paper also shows that the number of firms participating in the R&D contest can be endogenously determined in the two-stage R&D contest. The higher the extent of cost spillover, and the larger the effective prize, the more firms participate in the international R&D contest. Originality/value - Existing studies assume that firms winning the R&D contest enjoy perfect IPR to the output of their R&D activities. This is a very restrictive assumption in that other firms can copy the new products or processes. By allowing for the incompleteness of the IPR, the present paper develops a more realistic model of R&D contest. The novelty of the present paper is to allow for the possibility that the higher extent of IPR increases the prize and decreases positive cost externality at the same time. The findings of the present paper can serve as a basis for government policy toward R&D activities of firms and protection of IPRs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.11
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• pp.790-802
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• 2014

In cognitive radio technology, secondary users can determine the absence of PU by periodic sensing operation and cooperative sensing between SUs yields a significant sensing performance improvement. However, there exists a trade off between the gains in terms of probability of detection of the primary users and the costs of false alarm probability. Therefore, the cooperation group must maintain the suitable size. And secondary users should sense not only the currently using channels and but also other candidates channel to switch in accordance with sudden appearance of the primary user. In this paper, we propose an effective group cooperative sensing algorithm in distributed network situations that is considering both of inband and outband sensing using evolutionary game theory. We derived that the strategy group of secondary users converges to an ESS(Evolutionary sable state). Using a learning algorithm, each secondary user can converge to the ESS without the exchange of information to each other.

• Korean Journal of Agricultural Science
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• v.29 no.1
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• pp.55-65
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• 2002

The most representative fruit in Yanbian area is Applepear(Ping Guo Li). It has been a important resource of farm income. According to the economic growth and income Increase of individual consumers, food consumption pattern will be changed from grain to high value cash crops such as Applepear and vegetables. The globalization and adapt ion of free market oriented economic policy of China government have led to change the collective farming system to individual farm management system. The institutional transformation have brought about high productivity of farm products and incomes of farmers. Therefore the plantation area of Applepear and requirement of investment cost for establishment of Applepear farms have increased rapidly since the 1980's, the time of perestroika and glasnost in Chinese economy. In prosperity of Chinese agriculture, individual farmer's decision making as free selection of farmland use, selection of high pay-off crops, free sale of the products in free market and credit support for the project might be the most important factors. In case of Applepear farm development, net present value of the project net benefit was estimated at 55.518won per hectare and financial rate of return was 21%. The benefit/cost ratio of the project was 2.11. Considering 10% of discounting rate or the opportunity cost of capital in China the Applepear farm development project showed us economically feasible in the light of the above efficiency indices. The Chinese government has to support Applepear farm development project financially and institutionally considering the high-payoff benefit of the fruit and farmer's in come increase in the future.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.7
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• pp.543-552
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• 2013

For the safety messages in IEEE 802.11p/WAVE vehicles network environment, strict periodic beacon broadcasting requires status advertisement to assist the driver for safety. In crowded networks where beacon message are broadcasted at a high number of frequencies by many vehicles, which used for beacon sending, will be congested by the wireless medium due to the contention-window based IEEE 802.11p MAC. To resolve the congestion, we consider a MAC scheme based on slotted p-persistent CSMA as a simple non-cooperative Bayesian game which involves payoffs reflecting the attempt probability. Then, we derive Bayesian Nash Equilibrium (BNE) in a closed form. Using the BNE, we propose new congestion control algorithm to improve the performance of the beacon rate under saturation condition in IEEE 802.11p/WAVE vehicular networks. This algorithm explicitly computes packet delivery probability as a function of contention window (CW) size and number of vehicles. The proposed algorithm is validated against numerical simulation results to demonstrate its stability.

• Management & Information Systems Review
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• v.33 no.1
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• pp.45-63
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• 2014

A trading system is a computer trading program that automatically submits trades to an exchange. Mechanical a trading system to execute trade is spreading in the stock market. However, a trading system to trade a single asset might occur instability of the profit because payoff of this system is determined a asset movement. Therefore, it is necessary to develop a trading system that is trade two assets such as a pair trading that is to sell overvalued assets and buy the undervalued ones. The aim of this study is to propose a relative value based trading system designed to yield stable and profitable profits regardless of market conditions. In fact, we propose a procedure for building a trading system that is based on the rough set analysis of indicators derived from a price ratio between two assets. KOSPI 200 index futures and S&P 500 index futures are used as a data for evaluation of the proposed trading system. We intend to examine the usefulness of this model through an empirical study.