• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.9
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• pp.542-549
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• 2003

In this paper, a novel approach to generator maintenance scheduling strategy in competitive electricity markets based on non-cooperative dynamic game theory is presented. The main contribution of this study can be considered to develop a game-theoretic framework for analyzing strategic behaviors of generating companies (Gencos) from the standpoints of the generator maintenance-scheduling problem (GMP) game. To obtain the equilibrium solution for the GMP game, the GMP problem is formulated as a dynamic non-cooperative game with complete information. In the proposed game, the players correspond to the profit-maximizing individual Gencos, and the payoff of each player is defined as the profits from the energy market. The optimal maintenance schedule is defined by subgame perfect equilibrium of the game. Numerical results for two-Genco system by both proposed method and conventional one are used to demonstrate that 1) the proposed framework can be successfully applied in analyzing the strategic behaviors of each Genco in changed markets and 2) both methods show considerably different results in terms of market stability or system reliability. The result indicates that generator maintenance scheduling strategy is one of the crucial strategic decision-makings whereby Gencos can maximize their profits in a competitive market environment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.1
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• pp.8-15
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• 2015

This paper includes a method for estimating the parameter of a synchronous generator and exciter using the modified particle swarm optimization. A solid round rotor synchronous generator and exciter have been modeled with the saturation function. They are regarded as state of being cooperative to a infinite bus. The behavior characteristic of all particles assigned to a parameter needs to be reflected in the PSO algorithm to fine out more close result to the optimal solution. The results of the simulation to estimate the parameters of the synchronous generator and exciter in the modified PSO algorithm are described.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.2
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• pp.301-308
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• 2017

This paper proposes a disturbance observer based controller design method for generating and yawing control of windturbine with two cooperative generators. Windturbine system with two cooperative generators is a distinct structure in which the wind energy supplied by blade axis is converted into electrical energy by two cooperative generators. In this structure, two generators can be controlled independently and therefore they can generate power, simultaneously performing yawing control of nacelle without extra yawing mechanism by cooperatively controlling generating load in appropriate manner. Using this structural trait, this paper designs a disturbance observer based controller that enables the windturbine system with cooperative generators to generate and yaw stably, and verifies the performance of the controller experimentally by applying it to a small-scale windturbine system with the same structure.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.6
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• pp.63-69
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• 2008

In this paper, our goal is to find a power-effective protocol that improves the accuracy of transmission in sensor networks. Therefore we propose a cooperative communication protocol based on MRC(Maximal Ratio Combining) and cyclic code. In our proposal, one sensor node assists two others to communicate with a clusterhead that can get diversity effect and MRC can improve diversity effect also. The proposed protocol with cyclic code can correct error up to 3-bit and reduce decoding complexity compared with convolutional code. Simulation results reveal proposed protocol can save the network energy up to 6dB over single-hop protocol at BER(Bit Error Rate) of $10^{-2}$.

• Journal of KIISE:Software and Applications
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• v.34 no.2
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• pp.123-130
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• 2007

In this paper, we present an example-based natural language dialogue system for Electronic Program Guide Information Access. We introduce an effective and practical dialogue management technique incorporating dialogue examples and situation-based rules. In order to generate cooperative responses to smoothly lead the dialogue with users, our natural language dialogue system consists of natural language understanding, dialogue manager, system utterance generator. and EPG database manager. Each module is designed and implemented to make an effective and practical natural language dialogue system. In particular, in order to reflect the up-to-date EPG information which is updated frequently and periodically, we applied a web-mining technology to the EPG database manager, which builds the content database based on automatically extracted information from popular EPG websites. The automatically generated content database is used by other modules in the system for building their own resources. Evaluations show that our system performs EPG access task in high performance and can be managed with low cost.