• Title/Summary/Keyword: dft

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개미산에서 수소 생산용 Pd 기반 합금 촉매의 제일원리 설계

  • Jo, Jin-Won;Lee, Sang-Heon;Ham, Hyeong-Cheol
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.128.2-128.2
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    • 2016
  • 본 발표에서는 DFT를 사용하여 개미산으로부터 수소 생산용 Pd 기반 합금 촉매의 합리적 설계를 다룰 것이다. 특히, 합금 촉매 효과 [ligand (electronic) 및 strain effect)]가 어떻게 개미산으로부터 수소 생산의 반응성과 선택도에 영향을 미칠 수 있는지를 조사하였다. 이러한 결과는 높은 촉매 성능을 달성하기 위해서 다성분 촉매의 표면 활성을 타당하게 제어하는 것이 얼마는 중요한지를 보여준다 [J. Phys. Chem. C, 118, 22254-22560 (2014), J. Nanosci. and Nanotech., 15, 8233-8237 (2015), ACS Catalysis 6 (1), 134-142 (2016)].

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A Comparative Analysis of fault Detection Algorithm for AC Generator Protection (교류발전기 보호를 위한 고장검출 알고리즘의 비교 분석)

  • Park, Chul-Won;Shin, Kwang-Chul;Shin, Myong-Chul
    • Proceedings of the KIEE Conference
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    • 2007.11b
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    • pp.75-77
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    • 2007
  • Current percentage differential relaying has been recognized as the principal basis of main protection for stator windings of AC generator. The DWT has merit of obtaining frequency characteristics in time domain. In order to compensate for DFT's defects, we proposed fault detection algorithm using DWT. This paper describes a comparative analysis about conventional DFT-based DFR and advanced DWT-based relaying.

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Development of High Performance Dynamic System Monitor for Dynamic Modeling and Disturbance Monitoring (다이나믹 모델링 및 외란감시를 위한 고성능 Dynamic System Monitor 장비 개발)

  • Kim, D.J.;Lee, J.J.;Moon, Y.H.
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.50_51
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    • 2009
  • This paper describes the novel real-time embeded Dynamic System Monitor(KDSM) for dynamic device modeling and disturbace monitoring. The KDSM uses the variable resampling technique together with DFT algorithm so that it overcomes the shortcomings of the existing DFT algorithm at the big deviation of network frequency. The suggested algorithm is implemented by using the NI-PXI system, and verified by applying to the generator testing.

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Fault Detection Technique of Power System using DWT (DWT를 이용한 전력시스템의 고장검출 기법)

  • Park, Chul-Won;Ban, Yu-Hyeon
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.2017_2018
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    • 2009
  • DFT는 보호계전기의 알고리즘이나 디지털 미터에서 필수적으로 사용되고 있다. 그런데 DFT 필터는 시간 영역의 신호를 주파수 영역으로 변환하는 과정에서 시간 정보가 손실된다는 단점이 있기 때문에 이를 개선한 DWT가 제안되었다. 본 연구에서는 광역보호계전 지능화를 위한 네트워크 기반 주파수 모니터링 및 고장예측 시스템 개발을 위한 기초적인 연구로서 전력시스템의 초기고장검출과 고장징후 판단을 DWT의 상세계수 에너지성분의 합에 의하여 모색하였다.

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Mechanistic Investigation of the Copper(I)-Catalyzed Trifluoromethylthiolation Using Sulfonyl Hypervalent Iodonium Ylide as the SCF3 Source: A DFT Study

  • Park, Yoonsu;Jung, Yousung
    • Proceeding of EDISON Challenge
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    • 2014.03a
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    • pp.337-346
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    • 2014
  • Trifluoromethylthiol functional group(이하 -SCF3)은 약학적으로 유용한 물질이다. 이 연구는 최근 개발된 Shibata의 Direct trifluoromethylthiolation reaction의 반응 메커니즘을 계산화학적으로 평가했다. 반응 메커니즘은 크게 Carbene formation, Rearrangement, Electrophilic SCF3 reagent generation 세 단계로 나눌 수 있다. 각 과정에 대해 구조에 대한 full optimization이 진행되었고, 특히 alpha-carbene sulfonyl species의 thermal rearrangement에 관한 첫번째 계산화학적 평가가 이루어졌다.

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An FPGA implementation of phasor measurement algorithm for single-tone signal (단일 톤 신호의 페이저 측정기법 및 FPGA구현)

  • 안병선;김종윤;장태규
    • Proceedings of the IEEK Conference
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    • 2002.06d
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    • pp.171-174
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    • 2002
  • This paper presents an implementation method of phasor measurement device, which is based on the FPGA implementation of the sliding-DFT The design is verified by the timing simulation of its operation. The error effect of coefficient approximation and frequency deviation in the recursive implementation of the sliding-DFT is analytically derived and verified with the computer simulations.

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Efficient Signal Analysis of TDX-families PCM Signal Acquisition System with the Modified DFT

  • Lee, Jae-Kyung;Yoon, Dal-Hwan
    • Proceedings of the IEEK Conference
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    • 2002.07c
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    • pp.1913-1916
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    • 2002
  • In this paper, we have developed a PCM signal analysis system which can analyze status of signals sent from/received to the TDX-families PCM signaling service equipment. We propose the modified DFT to analyze the status of an acquired CM signal, discuss the algorithm and the discrimination of the analyzed signal.

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Iris Pattern Recognition Using the DFT Coefficients (DFT계수를 이용한 홍채 인식)

  • 고현주;전명근
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2001.05a
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    • pp.237-240
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    • 2001
  • In this work, we will present an iris pattern recognition method as a biometrically based technology for personal identification and authentication. For this, we propose a new algorithm for extraction unique feature from images of the iris of the human eye and representing these feature using the discrete fourier transform. From the computational simplicity of the adopted transform, we can obtain more fast and efficient results than previous ones.

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