• Journal of the Korean Home Economics Association
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• v.44 no.7 s.221
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• pp.99-111
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• 2006

This study was conducted to investigate children's emotional response, emotion regulation strategy, and emotion regulation effect (regulation effect of strategies), and to determine the relationships among emotion regulation strategy, emotion regulation effect and children's psychological well-being in anger, (ear, and disappointment situations. Emotion regulation strategy recomposed four strategies through factor analysis based on the children's direct answers to the question inquiring on the method used to regulate anger, fear, and disappointment. A total of 359 elementary school children in glades 5 or 6 selected one strategy use to regulate anger, fear, and disappointment. The effect of that selected strategy were estimated. Psychological well-being is evaluated by a questionnaire. The results of this study showed that most of elementary school children used the attention evocation strategy to regulate anger, fear, and disappointment, and this strategy was confirmed to be the most effective. Children's psychological well-being was associated with only emotion regulation effect in anger, fear, and disappointment situations.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.932-934
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• 1993

Optimum pole shape is designed to increase the levitation and propulsion force of magnetic levitation systems. Evolution Strategy is introduced as optimization method. Evolution Strategy is random based non-deterministic method, developed by combining Genetic Algorithm with Simulated Annealing. Trasnsrapid-06, which was developed in Germany, is referenced model to be analyze. Design variables are nodes which determine fields pole shape of a linear synchronous motor, and the model analyzed by F.E.M.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1515-1527
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• 2018

This paper presents a sensorless speed control of IPMSM (Interior Permanent Magnet Synchronous Motor) using the high-frequency (HF) square wave injection method. In the proposed HF pulsating square wave injection method, injection voltage is applied into the estimated d-axis of rotor and high-frequency induced q-axis current is considered to estimate the rotor position. Conventional square wave injection methods may need complex demodulation process to find rotor position, while in the proposed method, an easy demodulation process based on the rising-falling edge of the injected voltage and carrier induced q-axis current is implemented, which needs less processing time and improves control bandwidth. Unlike some saliency-based sensorless methods, the proposed method uses maximum torque per ampere (MTPA) strategy, instead of zero d-axis command current strategy, to improve control performance. Furthermore, this paper directly uses resultant d-axis current to detect the magnet polarity and eliminates the need to add an extra pulse injection for magnet polarity detection. As experimental results show, the proposed method can quickly find initial rotor position and MTPA strategy helps to improve the control performance. The effectiveness of the proposed method and all theoretical concepts are verified by mathematical equations, simulation, and experimental tests.

• Journal of KIISE:Databases
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• v.31 no.2
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• pp.122-131
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• 2004

Traditional works on indexing have been suggested for low dimensional data under dynamic environments. But recent database applications require efficient processing of huge sire of high dimensional data under static environments. Thus many indexing strategies suggested especially in partitioning ones do not adapt to these new environments. In our study, we point out these facts and propose a new partitioning strategy, which complies with new applications' requirements and is derived from analysis. As a preliminary step to propose our method, we apply a packing technique on the one hand and exploit observations on the Minkowski-sum cost model on the other, under uniform data distribution. Observations predict that unbalanced partitioning strategy may be more query-efficient than balanced partitioning strategy for high dimensional data. Thus we propose our method, called CSP (Cyclic Spliced Partitioning method). Analysis on this method explicitly suggests metrics on how to partition high dimensional data. By the cost model, simulations, and experiments, we show excellent performance of our method over balanced strategy. By experimental studies on other indices and packing methods, we also show the superiority of our method.

• International Journal of Costume and Fashion
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• v.5 no.1
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• pp.75-89
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• 2005

The purpose of this study is to empirically ascertain how the fitness between marketing strategy each firm chooses and environment facing each firm affects the performance of firms measured by the growth rate of market share and the growth rate of profit/sales ratio. In doing so, firms are divided into three groups. With regard to the marketing strategy, firms are classified into three groups based on marketing strategy type; prospector, analyzer, and defender. The main result of this study are as follows: First, responding firms are classified into prospector, analyzer, and defender following Miles & Snow's marketing strategy types. This classification is made using a self typing method and further confirmed by a factor analysis using a number of variables relating marketing objectives and marketing mix. Second, the results show that there are significant differences across marketing strategies in the performance measures of the growth rate of market share and profit/sales ratio. It seems, however, that there is no straight forward relationship between the marketing strategy and the performance measures. This strongly implies that the type of marketing strategy to be adopted by each firm should depend on the environment facing each firm. Third, the result indicates that the growth rate of market share tends to depend only on the marketing strategy type regardless of sufficiency and variation of environment, but profit/sales ratio tends to depend on the fitness between marketing strategy type and environment. It implies that a firm should adopt different marketing strategies for different environment characteristics, in order to enhance the efficiency of resources used reflected in the profit/sales ratio.

• Journal of Power Electronics
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• v.19 no.6
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• pp.1582-1590
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• 2019

A new method for reducing the common-mode current generated by the voltage variations in a two-inverter air conditioner system by applying a synchronized pulse-width modulation (PWM) strategy is proposed. The PWM signals of the master-mode inverter are generated based on the reference voltage, while those of the slave-mode inverter are output in the opposite direction when the master-mode inverter changes its switching state. However, the slave-mode control results in a mismatch between the reference voltage and the actual output voltage that is modified by synchronized control operation. The proposed method is capable of reducing and controlling this voltage error by performing signal selection in the vector space of the slave-mode inverter, which mitigates the distortion of the phase current. The efficacy of this method in reducing conducted emissions has been validated both theoretically and experimentally.

• Journal of Electrical Engineering and Technology
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• v.8 no.3
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• pp.393-401
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• 2013

This paper deals with the operation strategy of the Cheju AC network included MIHVDC system (Multi-Infeed HVDC system). In case that where several HVDC systems are located in the vicinity of each other, there are interactions between the different HVDC systems in such network configurations. The interactions which could be generated in multi-infeed HVDC are voltage stability, power stability and inertia stability, to analyze such systems in a systematic way to ensure that there are no risks of adverse interactions is very important. The developed method until now to analyze MIHVDC interaction is extended from MAP(Maximum Available Power) method for analyzing the power stability of the single-infeed HVDC system, this method is to solve the eigenstructure using the identified factors influencing the interactions. Finally, the algorithms which are introduced in this paper, to determine the operation strategy are applied to Cheju island network which is supplied by two HVDCs.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.6
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• pp.347-353
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• 2003

In models of imperfect competition of deregulated electricity markets, the key task is to find the Nash equilibrium(NE). The approaches for finding the NE have had two major bottlenecks: computation of mixed strategy equilibrium and treatment of multi-player games. This paper proposes a payoff matrix approach that resolves these bottlenecks. The proposed method can efficiently find a mixed strategy equilibrium in a multi-player game. The formulation of the m condition for a three-player game is introduced and a basic computation scheme of solving nonlinear equalities and checking inequalities is proposed. In order to relieve the inevitable burden of searching the subspace of payoffs, several techniques are adopted in this paper. Two example application problems arising from electricity markets and involving a Cournot and a Bertrand model, respectively, are investigated for verifying the proposed method.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.11
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• pp.541-546
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• 2006

In a levitation magnet system with large air gap, numerical method is needed because analytic method cannot consider the leakage flux properly. This paper conducted an optimal design of a levitation magnet system with large air gap which was used for an OLED system, where evolution strategy was adopted for optimal design algorithm. Levitation forces near the initial design were calculated first by using finite element method to reduce the computation time. During the optimization process, levitation forces of arbitrary dimension were obtained using the interpolation of the levitation forces which were calculated previously Weight of the maget system was chosen as the object function and it was used minimized.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.12
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• pp.597-602
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• 2002

The restructuring of power industry is still going on all over the world for last several decades. Many kinds of restructuring model have been studied, proposed, and applied. Among those models, power pool is more popular than other. This paper assumes the power pool market structure having competitive generation sector, and a new method is presented to build a bidding strategy in that market. The utilities participating in the market have the perfect information of their cost and price functions, but they don't know which strategy to be chosen by others. To define one's strategy as a vector, we make utility's cost/price functions into discrete step functions. An utility knows only his own strategy, so he estimates the other's cost/price functions into discrete step functions. An utility knows only his own strategy, so he estimates the other's strategy using Nash equilibrium or stochastic methods. And he also has to forecast the system demand. According to this forecasting result, his payoffs can be changed. Considering these all conditions, we formulate a bidding game problem and apply noncooperative game theory to that problem for the optimal strategy or solution. Some restrictive assumption are added for simplification of solving process. A numerical example is given in Case Study to show essential features and concrete results of this approach.