• 한국정밀공학회지
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• 제20권9호
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• pp.109-117
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• 2003

With development of high advanced technologies and skills, micro machining techniques also are being more functional and smaller. Some of the recently developed micro machining technologies are micro drilling, micro EDM, WEDG, LBM, micro milling, micro UVM etc. In these micro machining techniques, Micro -EDM is generally used for machining micro holes, pockets, and micro structures in difficult-cut-materials. For machining micro structures, first of all, tool electrode should be fabricated by WEDG process. In micro-EDM, parameters such as peak current, pulse width, duration time are very important to fabricate the tool electrode and micro structures. Developed experimental equipments are composed of RLC circuit with PWM. In this paper, using developed micro EDM machine, the characteristics of micro electro discharge machining are investigated at micro holes, slot, and pocket machining etc. Also the trends of tool wear are investigated in case of hole and slot machining.

• JSTS:Journal of Semiconductor Technology and Science
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• 제7권4호
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• pp.260-266
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• 2007

Analytical compact form models for the signal transients and crosstalk noise of inductive-effect-prominent multi-coupled RLC lines are developed. Capacitive and inductive coupling effects are investigated and formulated in terms of the equivalent transmission line model and transmission line parameters for fundamental modes. The signal transients and crosstalk noise expressions of two coupled lines are derived by using a waveform approximation technique. It is shown that the models have excellent agreement with SPICE simulation.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2001년도 가을 학술발표논문집 Vol.28 No.2 (3)
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• pp.499-501
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• 2001

무선 채널 상태는 같은 셀 안의 사용자의 수 또는 사용자의 움직이는 속도 등과 같은 많은 변수들로 인해 급격히 변화한다. 따라서 무선 채널의 효율적 관리는 무선 통신에 있어서 가장 중요한 고려사항이다. 효율적인 무선 채널 관리를 위해서는 정량적인 근거를 제시해 주는 기준인 트래픽 양 측정방안이 요구된다. 현재 3GPP의 UMTS문서에서 제시하고 있는 정량적인 근거는 오직 RLC 대회에 있는 양만을 참조한다. 이 경우 일정한 레이트(rate)론 유지하는 음성형 서비스(conversational service)에는 적당할 수 있지만 멀티미디어와 같이 레이트가 일정하지 않은 서데스에 대해서는 이후에 전송될 데이터에 대한 정확한 트래픽 양 측정이 불가능하다. 따라서 본 논문에서는 토큰 버켓 모델을 이용하여 이후에 들어올 데이터 양에 대하여 보다 정확한 트래픽 양을 예측할 수 있는 메커니즘을 제안한다.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권4호
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• pp.246-251
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• 2003

This paper proposes a new methodology for the estimation of impedance characteristics, which is one of the important issue in the power distribution network design of printed circuit boards. The modeling process of the proposed method divides the power distribution network into uniform segment, and each segment is modeled by distributed RLC transmission lines. Then, for the efficient computation of impedance characteristics in frequency domain. the proposed method uses a model-order reduction method.

• 디지털콘텐츠학회 논문지
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• 제6권3호
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• pp.169-174
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• 2005

본 논문은 Verilog HDL로 FPGA에 JPEG Decoder를 구현하여 TV에 JPEG 영상을 디스플레이 하기 위한 JPEG Image Display Board 설계 방법을 제안한다. 본 논문은 FPGA에 Decoder Algorithm을 구현하기 위한 효율적인 방안을 제시하였으며 JPEG Decoder Algorithm은 JPEG Standard Baseline에 기준으로 하여 설계 하였다. 압축된 JPEG bit stream을 저장하기 위하여 Nand Flash Memory를 사용하였으며, JPEG Decoding된 영상을 TV화면에서 확인하기 위하여 Video Encoder를 사용하였다. 또 한 JPEG 영상에 Text data를 쓰기 위하여 YCbCr의 출력 bit를 RGB 24bit로 변환하였다. Video Encoder에 변환된 RGB Data를 동기시켜 출력하기 위하여 CVBS 입력을 Sync Separator에 의해 Hsync, Vsync, Sync, Field signal로 분리하였다. 또한 Display B/D상의 스위치를 통하여 JPEG 모드와 일반영상 모드를 선택할 수 있게 입증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 추계학술대회 논문집
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• pp.133-137
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• 2004

PV system's islanding occurs when the uitilty grid is removed but local sources continue to operate and provide power to local loads. Islanding is one of the serious problems m an electric power system connected with dispersed power sources. Also, this can present safety hazards and the possibility of damage to other electric equipments. If the real and reactive power of RLC load and PV system are closely matched, islanding detection by passive methods becomes difficult. Novel islanding detection method using frequency drift is proposed for grid-connected PV system.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권6호
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• pp.294-302
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• 2005

PV system's islanding occurs when the uitilty grid is removed but local sources continue to operate and provide power to local loads. Islanding is one of the serious problems in an electric power system connected with dispersed power sources. Also, this can present safety hazards and the possibility of damage to other electric equipments. If the real and reactive power of RLC load and PV system are closely matched, islanding detection by passive methods becomes difficult. This paper shows the simulation and comparision for the previous active methods and novel islanding detection method using frequency drift is proposed for grid-connected PV system.

• Journal of electromagnetic engineering and science
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• 제11권3호
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• pp.192-200
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• 2011

This paper proposes a new modeling method for estimating the impedance of an on-chip power/ground meshed plane. Frequency dependent R, L, and C parameters are extracted based on the proposed method so that the model can be applied from DC to high frequencies. The meshed plane model is composed of two parts: coplanar multi strip (CMS) and conductor-backed CMS. The conformal mapping technique and the scaled conductivity concept are used for accurate modeling of the CMS. The developed microstrip approach is applied to model the conductor-backed CMS. The proposed modeling method has been successfully verified by comparing the impedance of RLC circuit based on extracted parameters and the simulated impedance using a 3D-field solver.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.591-594
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• 2005

Islanding of PV systems occurs when the uitilty grid is removed but local sources continue to operate and provide power to local loads. Islanding Is one of the serious problems in an electric power system connected with dispersed power sources. Also, this scan present safety hazards and the possibility of damage to other electric equipments. If the real and reactive power of RLC load and PV system are closely matched, islanding phenomena can't be detected by the passive methods. Several active methods were proposed to detect islanding phenomena. The most effective method is SFS method which was suggested by Sandia National Laboratory. In this paper, a new anti-islanding algorithm is proposed and its validity is verified through simulation and experimental results for utility interconnection of PV system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.769-771
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• 2000

저 주파수에서 인덕턴스를 정밀하게 측정하는 방법은 RLC를 이용한 resonance 방법과 교류브리지를 이용한 방법이 있다. 현재 선진 국가표준기관에서의 인덕턴스 표준유지는 약 5 ppm정도이고, 인덕턴스 측정브리지는 국가에 따라 자체 개발하여 사용하며 평균적으로 약 20 ppm의 불확도로 보급을 하고 있다. 이러한 세계적 수준으로 인덕턴스 표준을 유지, 보급하기 위하여 10nF의 전기용량 표준으로부터 10 mH의 인덕턴스를 유도할 수 있는 Maxwell-wein bridge가 개발이 되었다. 이 브리지가 개발됨으로서 10 mH의 경우 400 Hz$\sim$5 kHz의 주파수 범위내에서 약 8 ppm($2{\sigma}$)의 불화도로서 인덕턴스 표준을 유지할 수가 있게 되었다.