• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.254_255
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• 2009

본 논문에서는 비선형 특성의 STATCOM 시스템에 대해 강인한 PI 제어기를 설계하였다. 설계된 PI 제어기는 불확실성 변수에 대해 모든 동작 점에서 항상 안정하다는 것을 보드선도, 게인, 위상 여유, Nyquist 선도를 통해 검증하였다.

• Korean Journal of Mathematics
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• v.21 no.2
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• pp.203-212
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• 2013

We investigate the existence of solutions of the one-dimensional wave system $$u_{tt}-u_{xx}+{\mu}g(u+v)=f(u+v)\;\;in\;(-\frac{\pi}{2},\frac{\pi}{2}){\times}R,\\v_{tt}-v_{xx}+{\nu}g(u+v)=f(u+v)\;\;in\;(-\frac{\pi}{2},\frac{\pi}{2}){\times}R,$$ with Dirichlet boundary condition. We find them by applying linking inequlaities.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1991.10a
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• pp.10-11
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• 1991

In this paper, Arachidic Acid of long-chain fatty acid was soluted by chloroform and observed $\pi$-A curve in trough. In our experimental result, optimum pressure for fabricating the LB film was 30mN/m. In $\pi$-A curve measurment, temperature dependence was investigated between 20-50($^{\circ}C$). However, in this temperature range, the variation of solid phase pressure was not observed.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.825-827
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• 2001

In this paper, we made mathematical modeling of BLDC motor system and design of PI controller. Using Apache web-server and PHP web-programming, we embodied virtual laboratory for PI controller design of BLDC Motor system by using proportional constants$(K_P)$ and constants of integration$(K_I)$.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.345-347
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• 2006

신설 선로와 기존 선로와의 계통 연계시 상 배치에 따라 연계 후 발생하는 급격한 영상전류의 증가로 인하여 지락계전기의 동작 같은 계통에 악 영향을 미치는 현상이 일어난다. 이 논문은 송전선로의 연가철탑을 이용한 역상배치 시행여부에 따른 계통 해석과 상시 불평형률을 문경 변전소 신설에 따라 10월 가압 목표로 시공 중인 송전선로의 $1{\pi}$분기와 관련하여 ${\pi}$분기시의 이상적인 송전선로 상 배열을 분석한다.

• ETRI Journal
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• v.29 no.6
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• pp.838-840
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• 2007

The relation between the allowed range of variation of polarization controller wave-plates angles and the respective polarization scattering properties is investigated. It is demonstrated that a nearly uniform polarization scattering over the Poincare sphere is obtained using a concatenation of three polarization controllers with angles randomly changed between $-{\pi}$/4 and ${\pi}$/4. It is also shown that an improvement of the scattering properties is obtained if the configuration angles are allowed to change between $-{\pi}$/2 and ${\pi}$/2.

• Honam Mathematical Journal
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• v.2 no.1
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• pp.19-23
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• 1980

본(本) 논문(論文)은 Cohomotopy군(群)과 Cohomolopy군(群) 사이의 몇가지 관계(關係)를 구명(究明)한 것이다. 논문(論文)의 주부분(主部分)으로서 ⅰ) 어떤 조건하(條件下)에서 $${\pi}^m(X,A){\sim_=}H^m(X,A)$$ (Theorem 2, Corollary 3) ⅱ) 어떤 조건하(條件下)에서 $${\pi}^n(X,A)=0{\Leftarrow}{\Rightarrow}H^n(X,A)=0$$ (Theorem 4) ⅲ) 어떤 조건하(條件下)에서 $${\pi}^n(X){\sim_=}{\pi}^n(A){\Leftarrow}{\Rightarrow}H^n(X){\sim_=}H^n(A)$$ (Corollary 5) 가 성립(成立)함을 증명(證明)하였다.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.390-393
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• 1999

For high performance ac drives, the speed sensorless vector control and a speed control algorithm base on the Fuzzy PI controller have received increasing attention. A Fuzzy PI controller is used for robust and fast speed control and space vector modulation method is used for PWM wave generation in this proposed system. The computer simulation results show that the proposed controller are more excellent control characteristics than conventional PI controller in transient-state response.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.128.3-128
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• 2001

In this paper we proposed that the speed of induction motor is controlled by a PI controller, which could control unknown motor using Neural Network for auto-tuning of the PI parameter. The parameters of the PI controller were adjusted to reduce the speed error of the controlled motor. The input parameters of the Neural Network controller are the speed, q-axis current, and speed reference of the induction motor respectively. The usefulness of proposed controller will be confirmed by simulation which we compare with conventional PI controller.

• Journal of the Korean Society of Costume
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• v.34
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• pp.151-168
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• 1997

Pi was worn like a shawl or scarf in Western costume In a broad sense it means a skirt a towel a vest and a shawl However the subject of this study has limited a naarrow sense a long shawl Historically it appeared since Jin to Chung dynasty and had various names according to each dynasty Also Pi was changed its shape colour pat-terns and details with various names. Therefore the purpose of the study is to ana-lyze the formative characteristics of pi includ-ing how to wear it through Chinese history.