• Bulletin of the Korean Mathematical Society
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• v.38 no.1
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• pp.71-79
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• 2001

The purpose of this paper is to prove new equilibrium existence theorems of social systems with coordination under general conditions on the preference correspondence in locally convex spaces, and we also give an example which the previous existence results on SSC do not work but our theorem can be applied.

• KIEE International Transactions on Power Engineering
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• v.5A no.4
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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.

• 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.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.4
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• pp.1192-1207
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• 2014

Dynamic spectrum sharing is a key technology to improve spectrum utilization in wireless networks. The elastic spectrum management provides a new opportunity for licensed primary users and unlicensed secondary users to efficiently utilize the scarce wireless resource. In this paper, we present a game-theoretic framework for dynamic spectrum allocation where the primary users rent the unutilized spectrum to the secondary users for a monetary profit. In reality, due to the ON-OFF behavior of the primary user, the quantity of spectrum that can be opportunistically shared by the secondary users is limited. We model this situation with the renewal theory and formulate the spectrum pricing scheme with the Bertrand game, taking into account the scarcity of the spectrum. By the Nash-equilibrium pricing scheme, each player in the game continually converges to a strategy that maximizes its own profit. We also investigate the impact of several properties, including channel quality and spectrum substitutability. Based on the equilibrium analysis, we finally propose a decentralized algorithm that leads the primary users to the Nash-equilibrium, called DST. The stability of the proposed algorithm in terms of convergence to the Nash equilibrium is also studied.

• Journal of the Korea Institute of Building Construction
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• v.8 no.6
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• pp.65-74
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• 2008

The aim is to get comprehensive view point for the price of apartment. Apartment construction cost is the sun of land cost and building cost. Land price reflects the value of location where building stands. When the gap between price and affordability is narrow enough, effective demand promote apartment construction. The today's trends of rising price, which began in apartment housing, spreads to real estates market and finally overall consumer price. Problem is that price is decided only by supplier's interest. Equilibrium-pricing is common process in housing market. However it is important to review hedonic price and the factor of housing services and focused on the affordability of demanders. AHP analysis was used to study real needs and preference of demanders and dealt with 200 interviewees with brief checklists. We found that social factor is more important than building cost or site development. Especially location of apartment is most important to affect environment quality and accessibility to facilities.

• KDI Journal of Economic Policy
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• v.43 no.2
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• pp.1-22
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• 2021

The effects of social distancing measures on income distributions and aggregate variables are examined with an off-the-shelf heterogeneous-agent incomplete-market model. The model shows that social distancing measures, which limit households' labor supply, can decrease the labor supply of low-income households who hold insufficient assets and need income the most given their borrowing constraints. Social distancing measures can therefore exacerbate income inequality by lowering the incomes of the poor. An equilibrium interest rate can fall when the social distancing shock is expected to be persistent because households save more to prepare for rising consumption volatility given the possibility of binding to the labor supply constraint over time. When the shock is expected to be transitory, in contrast, the interest rate can rise upon the arrival of the shock because constrained households choose to borrow more to smooth consumption given the expectation that the shock will fade away. The model also shows that social distancing shocks, which diminish households' consumption demand, can decrease households' incomes evenly for every income quantile, having a limited impact on income inequality.

• Korean System Dynamics Review
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• v.1 no.1
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• pp.133-157
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• 2000

This paper deals with the social system from the point of system thinking consisting the fundamental construct of system dynamics. The Bertalanffy's general system theory, having been criticized because of its ambiguity, and the complex science theory, emerging system theory, are integrated by using the system thinking which is characterized with three concepts, 'feedback thinking', 'dynamic thinking', 'operational thinking'. In the integration, system thinking suggests the dynamic pattern of the social system have not only an equilibrium status but also complex status. The science of complexity gives an implication to system dynamics the important of the uncertainty and complexity if we interpret the social system as an open system. To show more concrete description, I simulate the cooperation model based on the iterated prisoner dilemma. The simulation results show the diverse patterns of cooperation and betrayal. Especially the sensitivity of initial payoff will cause the chaotic strategic landscapes as the game gose on. These results mean that we should not give the hasty prescription to control social system artificially. Because social system retains the self-organizing force in itself.

• Korean Journal of Social Welfare Studies
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• v.40 no.2
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• pp.89-122
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• 2009

This study was carried out to analyze the job of care managers in their social welfare practicing fields about the frequency of care management duties they perform, types of duties considered to be most important and the reason, and types of jobs counted to be the most difficult and the reason by qualitative case study research methods. The job area of care management was elicited using DACUM method, and those 9 job areas derived from it were analysed according to frequency of performance, importance and difficulty. The subjects were 10 social workers serving more than 3 years with major duty of care management and chosen by reputational-case selection, and those collected data analysis was operated according to embedded analysis types. We discussed the implication of this research. : The experience of participants are the process of maintaining the tension, and search the equilibrium point between client centered service and institutional pressure. According to the results we proposed ① Construction of community based social work network, ② Institutional installation for guarantee care manager's Job competence ③ Standard manual for equilibrium and upward equalization

• The Journal of Fisheries Business Administration
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• v.15 no.1
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• pp.1-57
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• 1984

The fisherman has been playing the roles of forming the fisheries village and surviving the fisheries production. Therefore, we should understand the nature of the fisherman's successor-cultivation which has been performed in order to maintain equlibrium between the fisheries economy and the national economy. Thesedays, fisherman's successor-cultivation mainly has been undertaken by the government in order to facilitate forming the economic foundation of fisherman's successor who has intended to choose "fisheries" as his own occupation in the future. From the above-mentioned, we find the meaning of the undertaking as both securing the foundation of living permanently and having the worth-while life of a professional fisherman by the survival and growth of his own business. And then, choosing the "fisheries" as an occupation, the successor should be satisfied with the requisites of occupation: 1) maintaining one's living, 2) working out one's individuality, 3) fulfilling one's social role-through engaging in the fisheries. Therefore, in order to have these requisites satisfied, I intend to suggest the followings : Firstly to maintain one's living, the environment of fisheies village should be kept in good condition to facilitate the successor's economic performance. Secondly to work out one's individuality, the fisheries' educational system should be adjusted to improve fisherman's ability. 1 hope to institute "the course of regional fisheries management" in fisheries high school and junior vocational collage, and "the school of fisheries management" for the learning of advanced fisheries knowledge. Thirdly to fulfill one's role, the opportunity actively participating in decision-making of the village's affair should be prepared more sufficiently, and the present fishing-centered fisheries system should be reformed into the fish-farming-centered fisheries system. To do this, the long-perspective vision is necessary. These three suggestions are come out from the macro-view point. Meanwhile the fisherman as an individual to improve his business is from the micro-view point. That is, the public aid, financial and legal, should be prepared. The above-mentioned suggestions are necessary to equalize fisherman's social status with other professional's especially from the result of improving the successor's economic force. Therefore, the principle of cultivating the fisherman's successor should be the principle of social equilibrium. be the principle of social equilibrium.

• Journal of applied mathematics & informatics
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• v.26 no.1_2
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• pp.337-347
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• 2008

Based on social welfare maximum theory, the optimal scale of power plants entering generation power market being is researched. A static non-cooperative game model for short-term optimization of power plants with different cost is presented. And the equilibrium solutions and the total social welfare are obtained. According to principle of maximum social welfare selection, the optimization model is solved, optimal number of power plants entering the market is determined. The optimization results can not only increase the customer surplus and improve power production efficiency, but also sustain normal profits of power plants and scale economy of power production, and the waste of resource can also be avoided. At last, case results show that the proposed model is efficient.