• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.263-269
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• 2018

In this study, a selective inverter operation between a 2-level voltage source converter (VSC) and a 3-level T-type VSC (3LT VSC) is proposed to improve the efficiency of a 3LT VSC. The 3LT VSC topology, except for its neutral-point switches, has similar operations as that of the 2-level VSC. If an operation mode is changed according to efficiency, the efficiency can be improved because efficiencies of each methods are depending on current and MI (Modulation Index). The proposed method calculates the power losses of the two topologies and operates as the having lower losses. To calculate the losses, the switching and conduction losses based on the operation mode of each topology were analyzed. The controller determined the operation mode of the 2- or 3-level VSC based on the power loss calculated during every cycle. The validity of the proposed control scheme was investigated through simulation and experiments. The waveform and average efficiency of each method were compared.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
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• pp.108-111
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• 2001

The electric power industries in Korea are launched into deregulation by introducing the CBP(Cost Based Pool), where generation sector of KEPCO was divided into six generation companies and the other sectors of KEPCO remains vertically integrated system. In deregulated market, participants are concerned with maximization of their profit rather than minimization of system-wide costs. Consequently, there are difficulties in applying the cost minimization for the scheduling of generation resources to CBP, because of the operation of pumped-storage hydroplants. This paper presents an operation method of pumped storage hydroplants which is helpful for the economic operation of power system considering the market in the CBP.

• 전자공학회논문지B
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• 제33B권6호
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• pp.54-63
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• 1996

We propose a 3rd order blind equalizer that incorporates a new transform method using either square root operation ($\sqrt{x]$) or reciprocal operation (1/x) in order to transform symmetric distribution of PAM signals at the transmitter, to asymmetric one. At the receiver, either the square operation or the reciprocal operation is needed to recover the asymmetrically transformed signals to the original ones after eualization. The reslts of the computer simulation, using the new method are better than the existing transform method using natural logarithm operation by the maximum of 8 dB in MSE. In addition, as the skewness of the asymmetrically transformed distribution has small values, the performances are improved.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1303-1308
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• 2004

This paper proposes a reduction method for the mis-operation analysis of the DC High Speed Circuit Breaker(HSCB) in electric railway substation system. The analysis method is based on present condition of operation which is a method for accuracy level up. There is reason to operation of HSCB that it is mis-operation of fault detection relay(50F), operation of ground fault relay(64P), and trouble of electric car. A countermeasure is relay resetting through field test, induction of GTOCB(Gate Turn Off Thyristor Circuit Breaker), HSVCB(High Speed Vacuum Circuit Breaker), coordination with electric car. The results presented in the paper can be used as a reference for maintenance free in electric railway substation system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.151-156
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• 2003

The Communication Based Train Control(CBTC) System generally used to improving existing lines in the world is efficient and stable for improvement. Also it is efficient for improvement because it does not cause any problems in operation of existing lines. We examined the mixed operation scheme for more efficient and stable improvement when improvement is implemented depending on aged equipment and the increased number of passengers in the Korean city railroad. The biggest point in the mixed operation is to implement a stable test without interfering with the operation of the existing lines. For this purpose, we deduced a method of installing the equipment, a method of testing depending on the installed equipment, and the types of mixed operation, and presented a scheme of execution of the methods depending on the mixed operation.

• 한국통신학회:학술대회논문집
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• 한국통신학회 1991년도 추계종합학술발표회논문집
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• pp.86-91
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• 1991

A capability of performing the optical logic and arithmetic operations is followed by an effective encoding technique. In this paper, we proposed the color light encoding technique. By using this encoding technique, the space bandwidth product(SBP) is minimized in the output plane. In addition, we proposed the pre-operation pro-carry processing method that performs faster than the same time operation and carry processing method in optical computing. We proposed that the color liquid crystal device(CLCD) is used as the encoded color light input source.

• 전자공학회논문지B
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• 제32B권6호
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• pp.862-867
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• 1995

In this paper a method to perform Exclusive-OR operation between two tabular type Boolean expressions is presented. The proposed method allows to solve the switching equations and the simultaneous equations in a rather direct manner, compared with Unger's method.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 추계학술대회
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• pp.1023-1024
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• 2015

본 논문에서는 Galois체에 기초를 둔 고효율 산술연산기 구성에 관한 한가지 방법을 제안하였다. 제안한 연산기는 기존의 방법에 비해 좀 더 규칙적이고 확장성이 용이한 이점이 있으며, 또한, 각종 멀티미디어 하드웨어 구성시의 기본인 연산기로 적용 및 응용할 수 있다. 향 후 연구과제로는 좀 더 콤팩트하고 효과적인 산술연산 알고리즘의 도출이 필요하며, 이에 논리연산기를 접목하여 산술연산 및 논리연산을 수행하는 연산전용 프로세서의 개발이 필요하다.

• 한국산학기술학회논문지
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• 제11권7호
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• pp.2603-2609
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• 2010

최근 항만에서는 이송장비의 운영 효율성 제고를 위해 운영방식의 개선에 관한 다양한 시도가 이루어지고 있다. 기존 조별운영 방식에서는 특정 안벽크레인에 지연이 발생하면 배정된 YT들도 함께 작업을 중단해야만 하는 문제가 생겼다. 이 문제를 해결하기 위해 본 연구에서는 운영 방식을 풀링운영 방식으로 전환하고 운영 효과를 높이기 위해 장치장 내에 무선 측위 장비를 설치하고 YT의 위치와 혼잡도를 측정하였다. 본 연구를 통해 풀링운영을 위한 YT의 이동을 실시간으로 추적할 수 있게 되었고 장치장의 혼잡도를 객관적으로 분석하고 평가하는 작업통제 방법이 마련되었다.

• 대한전기학회논문지
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• 제33권8호
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• pp.281-288
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• 1984

A new method of protecting 3-phase squirrel-cage induction motor aginst burning-out by unbalance operation is proposed. This paper studied various kinds of situations occurred by unbalance operating in 3-phase induction motor, and we provided the search coils in the slots of stator and rotor for the purpose of detecting electrical phenpmena during unbalance operation. Through experiments, we find that search coils in the slots of stator is effective method for protecting the induction motor from unbalance operating.