• Journal of applied mathematics & informatics
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• v.28 no.3_4
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• pp.1017-1023
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• 2010

We prove that a maximal ideal M of D[x] has two generators and is of the form where p is an irreducible element in a PID D having infinitely many nonassociate irreducible elements and q(x) is an irreducible non-constant polynomial in D[x]. Moreover, we find how minimal generators of maximal ideals of a polynomial ring D[x] over a DVR D consist of and how many generators those maximal ideals have.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.293-297
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• 1998

This paper presents a newly developed speed sensorless drive using RLS based on Neural Network Training Algorithm. The proposed algorithm has just the time-varying learning rate, while the wellknown back-propagation algorithm based on gradient descent has a constant learning rate. The number of iterations required by the new algorithm to converge is less than that of the back-propagation algorithm. The theoretical analysis and experimental results to verify the effectiveness of the proposed control strategy are described.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.179-182
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• 2002

This Paper described a robust control of an induction motor using a disturbance cancellation observer of a feedforward control, The speed response of conventional Pl controller characteristic is affected by variations of load torque disturbance. Tn the proposed system, the speed control characteristic using a feedforward control isn't affected by a load torque disturbance.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.433-437
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• 1998

Equalize SOC of the cell which effect on the charge.discharge ability and the efficiency of the battery, through the charge.discharge characteristic test of the battery source, and develope the high efficiency charge.discharge system in the series HEV have a constant engine-generator output. For this, in this paper, establish the electrical model and the condition of high efficiency charge.discharge, and proposed the improvement method of charge.discharge characteristic in the battery source that consist of twenty Ni-MH cells connected serial/parallel

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.495-498
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• 2003

Most PV (Photovoltaic) inverters are a voltage source type. Normally an input capacitor of this type is connected at the input of an inverter to keep the DC voltage constant. However, it does not seem to be well known how to determine the appropriate value of the capacitor. By developing non-linear transient analysis, the author suggests a guideline fur this approach. An implicit trapezoidal formula was used to do this calculation.

• Proceedings of the KWS Conference
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• 2002.05a
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• pp.65-67
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• 2002

The gas metal arc welding(GMAW) is regarded as one of the best candidate for welding automation in industrial joining application. It is important to monitor the weld quality for the high performance of weld automation. The measured analog signal is frequency analyzed by digital signal process method. In order to observe the welding phenomena and control welding condition, arc light, voltage, and current are measured at the same time. They are analyzed and compared with arc sound. for these experiments, a power source of constant voltage characteristics was used in the pure metal transfer mode.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.33 no.3
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• pp.100-105
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• 1984

The optimal Load-Frequency Control law is presented with the performance criterion which includes the changing rate of governor speed. The authors propose two controllers. One is a dynamic controller using the method of state augmentation and the other is a constant gain controller with use of the trace function lemma by Kleinman. For a more practical realization, a reduced-order Luenberger observer is applied in order to identify unmeasurable states and power demand. The control schemees presented here are tested through the model developed by Elgerd, and the usefulness is demonstrated.

• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.431-433
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• 2000

In this paper, we evaluated the dielectric properties and thermal analysis on sliced XLPE sheet from 154kV power cable and compared with 22kV XLPE sheet. As the result, dielectric constant was not applied voltage dependance but trended to increase with temperature. Test result presented that tan$\delta$ of XLPE with Interface was trend to increased.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2097-2099
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• 1998

This paper proposed an improvement in the Buck ZC-ZVS converter Presented in [1]. This is achieved by change the auxiliary switch position, which reduces its rating power. By employing saturable inductor, the maximum voltage stress across the main switch becomes constant and independent of the load current. Operating principle of Buck proposed topolo described and confirmed by simulation results.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.476-477
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• 2018

최근 휴대폰 등 DC 가전기기의 증대와 에너지 시간 이동이 가능한 저장장치를 겸비한 스마트그리드 출현으로 에너지를 저장하는 장치의 수요가 증가하고 있다. 본 논문에서는 충전시간이 많이 소요되는 정전압 충전 방식을 제거하고 정전류 충전방식으로만 배터리 충전을 완료할 수 있는 충전기법을 제안한다. 이를 위해 정전류 충전에 필요한 배터리 파라미터를 실시간으로 추정하여 배터리 전압을 추정할 수 있는 간략화된 알고리즘을 제안한다.