• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.8
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• pp.1441-1444
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• 2007

This paper presents a novel electrostatic drop-an-demand ejector with a conductive pole inside nozzle. The MEMS fabricated pole-type nozzle shows a significant improvement in the performance and reliability of forming meniscus and generating a micro dripping mode of droplet out of the meniscus. It is verified experimentally that the use of the pole-type nozzle. The liquid is used D20+SDS+SWNT (5 %wt). The gap between upper electrode and nozzle is about 600 um. Electrostatic drop-an-demand ejection is observed when a DC voltage of 1.5 kV is applied between the control electrode and ground electrode. Droplet diameter is $100{\mu}m$.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.360-364
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• 1995

A zero voltage switching (ZVS) three level resonant pole inverter is presented for high power GTO inverters. The concept of auxiliary resonant commutated pole(ARCP) for two level inverter is extended to the three level inverter. The proposed auxiliary commutation circuit consists of one resonant inductor and two bi-directional switches, which provides ZVS condition to the main devices without increasing device voltage or current stresses. The auxiliary device operates with zero current switching(ZCS) which enables use of the low cost thyristors. The proposed circuit can handle higher voltage and higher power(1-10MVA) comparing to the two level one. Operation and analysis of the proposed circuit are illustrated. Experimental results with 10 KW, 4 kHz prototype are presented to verify the principle of operation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.6
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• pp.118-124
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• 2009

In order to know the range of install possibles of the horizontal stay without general stay, strength characteristic tests were performed for the Vertical and 80[$^{\circ}$] inclined concrete poles. From the results of one cycle strength tests, the safety factors were 2.8, 2.5 and 2.1 for the poles of general load, heavy load and high strength load, respectively. However, the crack was occurred when the bending bounds of upper part of pole was above 2[$^{\circ}$], and working load was similar to the rated load of pole at this time. Therefore, it could be concluded that the reinforcement by the installation of the stay and the support was necessary certainly, if the bending bounds of pole, which was installed on a solid foundation, are above 2[$^{\circ}$].

• The Journal of Engineering Geology
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• v.32 no.4
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• pp.525-534
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• 2022

This investigation used two different geophysical logging techniques to confirm the depth to which a sheet pile was driven. Depth was estimated through analysis of the movement speed and three-component movement directions of a P-wave transmitted through the ground. It was also estimated by pole-pole and pole-dipole methods using electrical data logging to measure apparent resistivity. The two methods' respective results were 9.0 m (±1.5 m) and 7.5 m. As field ground conditions will include mixtures of various materials, electrical data logging is judged to be suitable for assessing depth due to its low signal-to-noise ratio.

• 한국지구물리탐사학회:학술대회논문집
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• 2000.09a
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• pp.19-40
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• 2000

We applied both SP monitoring and pole-pole array resistivity surveys and SP survey and dipole-dipole array resistivity survey to leakage problems in several embankments and dike, respectively, to estimate and detect the zone of leakage. The embankment is generally affected by tidal variation and has low resistivity characteristics due to the high saturation of seawater. According to this situation, SP monitoring and resistivity survey using pole-pole electrode array, which is relatively more effective to the conductive media, were carried out to delineate the leakage zones of sea water through the embankment. We checked out electrical conductivity(EC) and temperature variations along the inner part of the embankment to detect the zone of seawater leakage and found that the measured EC value agreed to that of seawater in the leakage zone and the temperature was lower than that of the vicinity of leakage zone. SP monitoring results were coincide with tidal variations at each embankment. Based on the survey results, it is concluded that both SP monitoring and the pole-pole array resistivity method are quite effective for investigation of seawater leakage zones in the embankment.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.2
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• pp.59-64
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• 2004

Study of an accurate and robust braking control method is required as a technical improvement to the servo system. In particular, the braker exhibiting constant braking performance under speed variation conditions of the prime mover needs to be investigated. In this paper, the braking torque of the eddy current braker between the electromagnet stator and rotating disk is analyzed. The torque-speed characteristics and accurate disk construction are represented. From the computer simulation results, it was found that eddy current braking torque is linear or approximately constant over the desired speed range depending on the rotor material, disk construction, pole number and pole displacement of the stator. These relations are confirmed by experimental results.

• Journal of information and communication convergence engineering
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• v.8 no.3
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• pp.333-338
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• 2010

This paper derives a nominal state relationship (NSR) from the data of a nominal system. Through an example of a second order system, it is shown that the relationship can be derived only in the system with different real eigenvalues. In higher order system, the relationship is expressed by using neural network (NN). The derived NSR is used to design a noble sliding surface with a nominal system characteristic. By using the sliding surface, the robustness of the sliding mode control (SMC) is added to the pole-placement control.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1551-1552
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• 2008

본 논문은 네트워크 기반 제어시스템(NCS: Networked Control Systems)에 모델매칭 제어기법을 적용한 효율적인 제어알고리즘을 제안한다. 비선형의 특징을 가지는 제어기 및 관측기의 시간지연을 Taylor 근사법으로 선형화하여 선형시스템 이론을 적용한 모델매칭 제어기를 설계하였다. 또한, 제어기의 차수를 우세극 기법과 극,영점 상쇄기법(Pole-Zero Cancelation)을 통해 저차화한 후 그 타당성을 검증하였다. 제안한 제어알고리즘의 컴퓨터 시뮬레이션을 실시하였으며 기존의 고차 모델매칭 제어기와 비교분석하여 타당성 및 신뢰성을 검증하였다.

• Journal of information and communication convergence engineering
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• v.7 no.3
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• pp.356-360
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• 2009

A novel method to derive a Nominal States Relationship (NSR) of a control system is proposed. The obtained relationship is used to design a sliding surface which can have the characteristic of a nominal system. With this sliding surface, a Sliding Mode Control (SMC) system which has the characteristics of the nominal system controlled by pole placement is designed for an uncertain system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.9
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• pp.40-46
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• 2012

The single-phase switched reluctance motor(SRM) has only one inductance variation and the positive torque is generated in the restricted section. So, it cannot be started by itself. To solve this problem, many researchers have addressed the several starting method for the single-phase SRM. This paper is focused on the torque characteristics of the single-phase SRM according to starting method. The four major starting method - permanent magnet, saturable stator pole, to grade the rotor, stepped rotor pole - is selected to analyze the torque characteristics. The analysis model of each starting method is designed to changed the pole shape or inserting other material in the basic model. The torque characteristics of each analysis model is obtained by using FEM analysis. The FEM analysis is performed at incremental rotor positions over half inductance cycle in any one pole with 250AT, 500AT, 750AT. The distortion factor of each analysis model is analyzed through the FFT to compare the distortion between basic model and four analysis model.