• Journal of Institute of Control, Robotics and Systems
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• v.6 no.2
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• pp.271-271
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• 2000

Although inverter-driven hydraulic elevators(HEL's) have advantages over traditional valve-controlled HEL's energy efficiency and performance they need robustness in performance and stability to accomodate nonlinearities big parametric variations and resonances in mechanical-hydraulic inner system. In this paper a robust controller based on DGKF/μ mixed approach is applied to a HEL system with carring capacity of 24 persons for Incheon International Airport. The results of a test tower(T/T) has shown good ro-bustness in performance and stability of the proposed controller thereby proving a feasibility of this robust controller-based approach for other HEL problems.

• Journal of the Korean Society of Combustion
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• v.14 no.3
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• pp.24-28
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• 2009

To improve its efficiency, most of the industrial furnace had been used recuperator. However, commonly used metal recuperator is not suitable under condition of temperature higher than $1000^{\circ}C$. The other hand, ceramic recuperator is able to use in high temperature condition. In the present study, the design program based on the basic heat exchanger design theory, and CFD modelling are applied to ceramic recuperator to verify the design results. Using design program to find the optimum design factor on the variation of recuperator condition. The result of this study are as follows : Thinner fin-plate thickness reduces pressure drop and increases heat-transfer rate, However, thin plate or plate with thin thickness(< 5 mm) is difficult to manufacture, due to limited mechanically strength.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.246-248
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• 2009

본 논문에서는 장력 검출 장치(로드셀, 댄서 등) 가장착되어 있는 생산 설비에서 강선, 강판, 제지, 섬유, 비닐 등과 같은 소재의 장력을 정밀하게 제어하기 위한 인버터의 장력 제어 전용 PID 제어기와 직경 또는 소재의 두께를 실시간으로 추정하여 인버터의 출력 주파수를 보정하는 추정기를 제안한다. 본 논문에서 제안된 방법을 다양한 용량(0.37kW~160kW) 대의 인버터에 탑재하여 실제 부하에 적용함으로써 산업 현장에서 요구하는 수준이상의 우수한 제어 성능을 나타냄을 확인하였다.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.4
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• pp.281-285
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• 2018

An isolated feedback method for measuring the inverter DC-link voltage is proposed. This method provides a simple and economical solution to inverter control systems that use a flyback converter as a controller power supply. In the proposed method, data on the DC-link voltage are acquired when the primary side voltage appears on the secondary side of the flyback transformer, thereby eliminating the need to adopt an extra signal isolation method. To solve the non-synchronization problem between the flyback converter switching and main controller sampling, the external interrupt function of the micro-controller is used as a trigger signal for the A/D conversion.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.290-291
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• 2011

본 논문에서는 전압 사용율 증대를 통한 매입형 영구자석 동기 전동기의 약자속 운전 성능 향상 방법을 제시한다. 팬, 펌프 등과 같이 고속 운전이 빈번한 분야에 사용되는 매입형 영구자석 동기 전동기는 운전 속도에 따라, 적절한 약자속 운전 방법이 필요하다. 본 논문에서는 전류 지령 수정을 하는 매입형 영구자석 동기전동기의 약자속 운전 방법을 제시하고, 실험을 통하여 그 타당성을 입증하였다.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.294-295
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• 2011

This paper presents the design and development of Web control algorithm of continuous process control system using vector inverter. Web algorithm used tension control without the tension sensor, and it is to calculate the diameter of Web materials with maintain Web tension. The performance of Web control in this paper is verified by experiment.

• Journal for History of Mathematics
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• v.22 no.4
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• pp.67-82
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• 2009

We study Choi Suk Jung's on perspective of philosophy of mathematics. He explains Chosun mathematics as systems of Changes through and redefines on So Kang Gul's Sasang theory. This is the unique view on Chosun mathematics. we conjecture that Choi Suk Jung tries to establish the mathematical principle on So Kang Gul's Sasang theory.

• KLA journal
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• v.47 no.1 s.368
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• pp.24-45
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• 2006

지난 연말의‘도서관계 10대뉴스’에서 보았듯이 2005년에는 도서관법 전면개정 추진, 도서관에 개인정보인권 보호조치 권고, 저작권법 개정, 사서교사 임용, 주40시간 근무제, 독서문화 확산 등 여러가지 큼직한 일들이 있었다. 2006년도에는 그 어느 해보다 많은 변화가 예상된다. 특히 세계도서관인들의 축제인 <2006서울세계도서관정보대회>가 서울에서 열린다. 세계에 한국의 도서관문화와 사서들의 활동을 알릴 수 있는 좋은 기회가 될 수 있도록 도서관인 모두의 적극적인 관심과 홍보, 참여가 매우 중요하다. 이외에도 도서관법, 저작권법, 학교도서관진흥법 등 도서관 관련법의 제도 정비, 여전히 풀어야할 과제로 남아있는 공공도서관 민간위탁 등이 주요 이슈로 부각 될 전망이다. 프랑스의 석학 자크 아탈리는“변화를 받아들일 줄 모르면 그 존재가 사라진다.”“변화를 수용할 줄 알아야 살아남을 수 있다.”고 강조한바 있다. 변화는 21세기를 살아가는 우리들에게 매우 중요한 메시지를 남긴다. 그“변화”의 중심에 도서관계가 자리잡아 사회 속에 더 큰 부분으로 자리 매김 할 수 있는 한 해가 되기를 바란다. ■ 편집자 주

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.12
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• pp.649-654
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• 2003

The simplest method for measuring output currents of the three phase inverters is to measure them with three current sensors such as hall sensors. This method requires at least two current sensors, and these types of sensors are somewhat expensive. More economical method is measuring DC link current with a simple shunt resistor, then, reconstructing output current using the DC link current value and the switching status. However, in low speed region, the measurement becomes difficult and even impossible due to the requirement of minimum switching duration for A/D conversion. These problems can be overcome by limitation of switching duration. Limitation of switching, however, causes voltage and current distortion. Owing to compensation, distortion can be effectively suppressed. However these increase acoustic noise due to increment of current ripple. In this paper, a current measurement method is proposed, which can reduce minimum switching duration resulting in reduction of acoustic noise. The validity of proposed method is confirmed through experiment.

• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.263-268
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• 2008

In a residential complex case, the efficiency of land use are maximized, but a variation of external condition such as load in-equality, the increase in wind velocity and solar radiation by a height causes increasing energy in a building. Besides, because of increasing window size for a lighting and a view, it comes heating load in winter and cooling load in summer. A choice of cooling-system is important for this reason. Recently an internal high-rise residential complex installs an air-cooling system and operates individual heating. However, this study applies water-cooling used one public cooling-tower instead of an air-cooling system, also with an efficiency test of an air and a water-cooling system, consider an internal applicability.