• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.182-188
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• 2017

An arc eliminator allows a surge current bypass rapidly into the earth to facilitate the circuit breaking process and increase the stability of the load circuit. Thomson coil actuator (TCA) is a type of actuator that can function as an arc eliminator. The TCA has a simple structure and significantly rapid speed compared to the other types of actuators. In this paper, significant variables, which have a dominant effect on the performance of the TCA, are investigated in detail. Using these variables and an optimization algorithm, an optimal design strategy for the TCA is proposed in this research. The efficacy of the proposed optimal design strategy and the feasibility of the application of the designed TCA for a high power circuit breaker as the arc eliminators are validated through the experiment.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2082-2084
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• 1997

This paper proposes a new control strategy of bidirectional uninterruptible power supply(UPS) with the performance of active power filter which compensate the harmonics and reactive power. To improve the transient response for the effective compensation in active power filter mode, it is considered that a simple and precise calculation method of the compensation reference current for the harmonics and reactive power compensation. So a novel closed-loop control strategy is used to calculate the reference current. And the current regulated instantaneous voltage control scheme is used in back-up power mode. The system model and control algorithm are described and analyzed, and the system Performance is verified by the simulation and experimental results.

• Journal of Families and Better Life
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• v.15 no.1
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• pp.13-26
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• 1997

The study was to explore the housework time management strategies and time spent in housework of employed wives and to understand the variables influenced on them. The samples were composed of 271 employed wives living in Chunlabuk-Do. The results were as follows: 1) The employed wives spends average 4.5 hours a day on the housework. The significant differences were ground in the housework time related to all demo-graphic variables. 2) The level of the housework time management strategies of employed wives was lower than the average. The most influential variable on the housework time management strategies of employed wives was the level of education the monthly income and employment types. A employed wives with the higher work status education level and income level utilized more efficient time strategies. 3) The major strategy which influences the housework time is that of simplification. Especially occupation of housewives and type of house interact with the strategy of sim lification. That is as the housewives with the jobs of blue-collar production-technology and clergycal technology use the simplification strategy much their amount of housework time was reduced.

• Korean Management Science Review
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• v.14 no.2
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• pp.139-159
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• 1997

Recently banking industry is experiencing fundamental changes by advancement of information technology. The traditional role of branches is rapidly being replaced with new electronic service channels such as ATM. Phone and PC for they are time-saving and convenient. Automated service channel strategy of retail banks is divided into two different ways, automation and networking. Automation is mainly focused on cost reduction related to the branch operation, while networking is on expansion of customer contact points. Strategic types of banks can be defined from a matrix model shere the positioning is determined by the extent of automation and networking. The effectiveness of automated channel strategy depends on how separate strategic types show their performance. Results for deposits and productivity will be given to verify the economic performance of each strategic type.

• ICROS
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• v.1 no.1
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• pp.16-16
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• 1995

Like the usual systems, the industrial robot manipulator has some constraints for motion. Usually we hope that the manipulators move fast to accomplish the given task. The problem can be formulated as the time-optimal control problem under the constraints such as the limits of velocity, acceleration and jerk. But it is very difficult to obtain the exact solution of the time-optimal control problem. This paper solves this problem in two steps. In the first step, we find the minimum time trajectories by optimizing cubic polynomial joint trajectories under the physical constraints using the modified evolution strategy. In the second step, the controller is optimized for robot manipulator to track precisely the optimized trajectory found in the previous step. Experimental results for SCARA type manipulator show that the proposed method is very useful.

• Transactions on Control, Automation and Systems Engineering
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• v.1 no.1
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• pp.16-20
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• 1999

Like the usual systems, the industrial robot manipulator has some constraints for motion. Usually we hope that the manipulators move fast to accomplish the given task. The problem can be formulated as the time-optimal control problem under the constraints such as the limits of velocity, acceleration and jerk. But it is very difficult to obtain the exact solution of the time-optimal control problem. This paper solves this problem in two steps. In the first step, we find the minimum time trajectories by optimizing cubic polynomial joint trajectories under the physical constraints using the modified evolution strategy. In the second step, the controller is optimized for robot manipulator to track precisely the optimized trajectory found in the previous step. Experimental results for SCARA type manipulator show that the proposed method is very useful.

• ETRI Journal
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• v.28 no.1
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• pp.77-83
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• 2006

In order to improve the accuracy of cell selection in heterogeneous cellular systems, this paper proposes a fuzzy multiple-objective decision-based cell selection (FMDCS) strategy. Since heterogeneous cellular systems have different access technologies and multiple traffic classes, the strategy adopts cell type, data rate, coverage, transmission delay, and call arrival rate as evaluation indices, and uses different weight vectors according to the traffic classes of the mobile host. Then, a fuzzy multiple-objective decision algorithm is applied to select the optimal cell from all candidates. This paper also gives an instance analysis and simulation. The instance analysis shows FMDCS makes different selections for different traffic classes. Simulation results of the after-handoff quality-of-service (QoS) show the selected cell can provide MH optimal service.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.3
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• pp.262-269
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• 2005

Automatic landing of UAVs receives increasing interest these days, with increasing number of the developed UAV systems. In this paper, a glidepath tracking algorithm of the subscale UAV was proposed and the performance was analyzed. Flight data analysis shows that the existing autolanding flight control algorithm has a classical type glidepath control. This paper presents an alternative glidepath tracking strategy based on embedded flight control law. The performance of the proposed strategy was investigated through the TDP(Touch Down Point) error analysis with regard to various flight environment: steady headwind, atmospheric disturbance, communication transfer delay. It was verified that the proposed glidepath tracking strategy can be successfully applied to the practical autolanding of UAV systems.

• Journal of the Korean Operations Research and Management Science Society
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• v.14 no.2
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• pp.139-139
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• 1989

Recently banking industry is experiencing fundamental changes by advancement of information technology. The traditional role of branches is rapidly being replaced with new electronic service channels such as ATM. Phone and PC for they are time-saving and convenient. Automated service channel strategy of retail banks is divided into two different ways, automation and networking. Automation is mainly focused on cost reduction related to the branch operation, while networking is on expansion of customer contact points. Strategic types of banks can be defined from a matrix model where the positioning is determined by the extent of automation and networking. The effectiveness of automated channel strategy depends on how separate strategic types show their performance. Results for deposits and productivity will be given to verify the economic performance of each strategic type.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.21-23
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• 1997

The analysis of the permanent type synchronous motor is performed by using the finite element method (FEM). The optimal design of the permanent magnet is presented for minimizing cogging torque in this paper. The cogging torque is expressed in terms of scalar potential computed by the virtual work formula. The minimization of cogging torque is achieved by using the ( ${\mu}$ + ${\lambda}$ ) Evolution Strategy (ES) and the selected flux densities are used to a constraint.