• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1822-1824
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• 1996

Damage and upset of control and communication equipment due to transient overvoltages which occur due primarily to internal switching surge and external lightning surge are an important problems in electromagnetic compatibility(EMC). In this paper, we analyzed operation characteristic of metal oxide varistor widely used low voltage AC line using the electromagnetic transients program(EMTP) and compare it with experimental results and also, we modeled combination generator producing $1.2/50{\mu}s$ open circuit voltage and $8/20{\mu}s$ short circuit current as a source which is critical in calculating operation characteristic. Simulation results showed that most of Transient energy consumes at MOV located in service entrance side than load side, and it showed similar to experimental results. Therefore, entrance side MOV should be selected more energy capacity than that of load side MOV.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.155-156
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• 2015

Recently, electricity consumption has rapidly increased along with economic growth. The operating strategy using emergency generator is aimed, to resolve a demand response management. For strategy of peak shedding using emergency generator, it is essential to introduce the fast transfer switching device. One of the most effective solutions is to use a static transfer switch (STS) based on thyristor. However, the characteristic of natural commutated SCR thyristor should anticipate short duration voltage sag. STS system thus requires more than a quarter cycle to successfully complete transfer process. This paper proposes the operation scheme of the STS system using the forced-commutation technique to mitigate instantaneous voltage sag during peak transfer process. Proposed STS system improved turn-off characteristic thus accomplishes the peak load shedding satisfied power quality. Performance of the proposed STS system is evaluated using electromagnetic transient program (EMTP) to confirm the effectiveness.

• 대한전기학회논문지:시스템및제어부문D
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• 제51권2호
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• pp.86-88
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• 2002

An estimation method for the characteristic parameters in the low frequency signal is proposed in this paper. A low frequency signal is assumed to be modulated or distorted by high frequency terms. The algorithm proposed in this paper is designed to select set of local maximums in a successive manner, hence it is denoted as the iterative peak picking(IPP) algorithm. The IPP algorithm is operating in the time domain and is using only the comparison operation between two neighboring samples. Therefore, its computational complexity is very low and the delay caused by the computation is negligible, which make the real-time operation possible with economic hardware. The proposed algorithm is verified on the pitch estimation of speech signal and blood pulse estimation.

• Journal of electromagnetic engineering and science
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• 제2권2호
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• pp.93-99
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• 2002

The Cartesian loop chip which is one of key devices in narrow-band Walky-Talky transmitter using RZ-SSB modulation method was designed and implemented with 0.35 Um CMOS technology. The reduced size and low cost of transmitter were available by the use of direct-conversion and Cartesian loop chip, which improved the power efficiency and linearity of transmitting path. In addition, low power operation was possible through CMOS technology. The performance test results of transmitter showed -23 dBc improvement of IMD level and -30 dEc below suppression of SSB characteristic in the operation of Cartesian loop chip (closed-loop). At that time, the transmitting power was about 37 dBm (5 W). The main parameters to improve the transmitting characteristic and to compensate the distortion in feed back loop such as DC-offset, loop gain and phase value are interfaced with notebook PC to be controlled with S/W.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.494-496
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• 2003

This paper analyses the operation characteristic of distance relay when the single line to ground occurs in underground power cable systems that reduction device of sheath circulating current is installed. To apply that reduction device to actual system, the change of line impedance calculated at relay point is also analysed by the connection type of SVLs and fault location, fault inception angle with the installation of reduction device of reactor or not.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.31-33
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• 2003

Recently, KARI developed in-house meteorological sensor processing system named MESIS for GOES GVAR 5-CH Imager for better KOMPSAT EOC mission operation. MESIS consists of antenna system, receiver, serial telemetry card, processing and mapping software, and 2 NT PC systems. This paper shows system requirement, system design, characteristic and test results of processing system. System operation concept and sample image are also provided. Implemented system was proven to be fully operational through lots of operations covering from RF signal reception to web publishing.

• 산학경영연구
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• 제20권1호
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• pp.33-53
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• 2007

환경문제가 세계 각국의 중요한 이슈가 되고 있으며, 이를 해결하기 위해서는 자원순환형 사회시스템이 구축되어야 하며, 물류분야에서도 그 중요성이 부각되고 있다. 간 연구의 목적은 순환형 사회시스템 구축요인인 근원적 감축, 재사용, 재활용과 기업의 물류운영 특성인 통합성, 혁신성, 대응성과의 관계 및 물류성과와의 관계, 이들 요소가 기업규모별로 물류성과에 미치는 효과와 그 영향요인을 분석하여 방향을 제시하고자 하는데 있다. 이 목적을 달성하기 위하여 제조기업을 대상으로 문헌연구와 실증연구를 병행하였다. 본 연구는 기존의 물류 연구들과 달리 순환형 사회시스템 구축요인과 물류운영특성이 물류성과에 미치는 영향을 분석하였다는 데 의의가 있다고 하겠다.

• 한국항만경제학회지
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• 제24권1호
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• pp.85-102
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• 2008

본 연구에서는 물류정보시스템을 도입활용하고 있는 무역업체들을 대상으로 내부업무효율성과 조직혁신정도를 조절변수로 하여, 내부업무효율성과 조직혁신정도가 높은 집단과 낮은 집단으로 구분하여, 이들 각 집단의 물류정보시스템 특성변수가 성과(이용자가치와 인식된 유용성)에 미치는 영향을 분석하였다. 연구결과, 구조화된 업무 환경에서 물류정보시스템을 통한 지속적인 업무수행과 더불어 조직혁신을 위한 기업차원에서의 노력이 병행되어야 하며, 물류정보시스템 도입 무역업체들은 정기적으로 기업의 업무활동전반에 대한 정확한 평가와, 전략수립을 통해 물류정보 시스템의 성과 제고를 위한 노력을 기울여야 할 것이며, 본 연구에서 나타난 바와 같이 물류정보시스템 도입 무역업체들의 낮은 조직혁신정도를 향상시킬 수 있는 조직자체의 각성과 노력이 뒤따라야 할 것이다.

• 한국해양공학회지
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• 제9권1호
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• pp.101-110
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• 1995

In SMA(Shape Memory Alloy), the degradation by fatigue is one of the most important problems to be overcome, when SMA is used for robot-actuator materials. The actuator is operated repetitively for long time and its repeating operation develops the fatigue degradation of SMA. The fatigue degradation changes the transformation temperature and deformation behavior and results in inaccurate operation and deformation which results form repeating operation is to be investigated in advance and the scheme to resolve those problems have to be made for the design of actuator. In this paper, for the improvement of the fatigue degradation by repetive movement and better control of the correct movement by the stability of martensite transformation in the development of Robots actuator, Pre-strain(0, 1.5, 5, 8%) are loaded in the specimens and fatigue testing were carried out by the method of heating and cooling in direct condition. From the results of these experiments, the effect on pre-strain which affect the transformation characteristic and fatigue degradation phenomena were correctly investigated.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.917-921
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• 2004

Principle of mailing list was distributed messages to all subscribers in one time. But mailing list operation has constructed a network traffic problem. Because mailing list manager distributed mails without concentrate on subscriber network. If our network has many of subscribers, there will be redundant data in traffic channel. Submailing list has purpose to reduce problems. Analyses of mailing list characteristic in electronic mail were a feature of submailing list system, which manage by human hand (Network Administrator). That will cause trouble for network traffic if Network Administrator could not seek for mailing list characteristic from e-mails in due time. This article will present ideas and recognize methodology for automatic working in submailing list system. Recognize step begin with capture process, which use to trap e-mail information from transfer channel. Next process is preparing raw data into recognition format. Then the third one is recognize part and find out confidential factor. The last process is make decision and determine which electronic mail has properties of mailing list characteristic. Afterward deliver result to submailing list for carry on.