• 정보처리학회논문지B
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• 제13B권1호
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• pp.27-34
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• 2006

본 연구에서는 엔트로피를 이용한 독립성분분석(ICA : Independent Component Analysis)에서 점수함수(score function)를 생성하는 알고리즘을 제안한다. 점수함수를 생성하기 위해서 원 신호(original signals)에 대한 확률밀도함수의 추정이 반드시 필요하고 밀도함수가 미분 가능해야 한다. 따라서 원 신호에 따른 적응적인 점수 함수를 유도할 수 있도록 커널 기반의 밀도추정(kernel density estimation)방법을 사용하였으며, 보다 빠른 밀도 추정 계산을 위해서 식의 형태를 컨볼루션(convolution) 변환 한 후, 컨볼루션을 빠르게 계산할 수 있는 FFT(Fast Fourier Transform) 알고리즘을 이용하였다. 제안한 점수함수 생성 방법은 원 신호에 확률밀도분포와 추정된 신호의 확률밀도 분포의 오차를 줄이는 역할을 한다 실험 결과, 암묵신호분리(blind source separation)문제에서 기존의 Extended Infomax 알고리즘과 Fixed Point ICA 보다 원 신호와 유사한 밀도함수를 추정하였고, 분리된 신호의 신호대잡음비등(SNR)에 있어서 향상된 성능을 얻을 수 있었다.

• ETRI Journal
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• 제32권6호
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• pp.837-842
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• 2010

This paper proposes robust source localization methods for estimating the azimuth angle, elevation angle, velocity, and range using a low-complexity planar antenna array in impulsive non-Gaussian noise environments. The proposed robust source localization methods for wireless communication applications are based on nonlinear M-estimation provided from Huber and Hampel. Simulation results show the robustness performance of the proposed robust methods in impulsive non-Gaussian noise.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.485-488
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• 1999

In this paper, a current control system for single phase PWM AC/DC converter without the source voltage sensors is proposed. The sinusoidal input current and unity effective power factor are realised based on the estimated source voltage in the controller. The estimation of source voltage is performed by the reduced-order Luenberger observer using actual currents. The estimated source voltage is used to accomplish unity power factor. The proposed method is proved by experiments.

• 전기학회논문지
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• 제57권4호
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• pp.629-634
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• 2008

In this paper, we propose a simple numerical formula which can estimate the additional delay time due to interconnection branches in general source-termination scheme. We show that interconnection branches have influence on both signal quality and time delay. Using the proposed numerical formula, time delay can be easily predicted by system designers.

• ETRI Journal
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• 제34권6호
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• pp.978-981
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• 2012

We present an analytic solution to the projector pose estimation problem for the pinhole projection model in which the source image is a centered rectangle with an unknown aspect ratio. From a single quadrilateral given as a target image, our solution gives the position and orientation of a projector as well as the aspect ratio of a source image. The proposed method decomposes the problem into two pose estimation problems of coupled line projectors aligned at each diagonal of the given quadrilateral and then computes the common solution that satisfies the relevant geometric constraints. The solution is formulated as simple analytic equations. We also provide a determinant of projectability of an arbitrary quadrilateral.

• 전기학회논문지
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• 제58권3호
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• pp.502-508
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• 2009

The method to determine the operating current of HTS magnets needs to be different from that of LTS magnets. This paper presented estimation of the critical current of pancake windings. The pancake windings can be excited by a single power source or by multiple power sources. Critical currents were determined by using field dependent E-J relation. For the better estimation of the critical current, a new method to define the magnetic field of the HTS wire has been proposed. Calculated critical currents of pancake windings were compared with measured ones of the HTS BSCCO magnet consisting of 10 pancake windings. According to the test results, the estimated critical currents of pancake windings agreed well with that of measured ones. Effects of the single and multiple power source excitation on the critical currents have been also examined.

• 한국인쇄학회지
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• 제22권1호
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• pp.9-18
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• 2004

Recently as color image processing to be become independent have been desired at the light source in an image processing and it have been enlarged. An image processing of the light source which is become independent means an image processing which uses a spectral reflectance information. We improved it in the spectral reflectance estimation method which uses existing 3-band image in this research that the improvement of an identity color population generation method which uses the hue angle and the processing speed improvement and introduces a labelling method. The precision of a spectral reflectance estimation appeared to the ${\Delta}E^*_{ab}$ of an average 2.7 comparing with the measurement price. The practical use possibility came to be fast and appeared a processing speed compared with existing method.

• Current Optics and Photonics
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• 제1권6호
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• pp.573-578
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• 2017

Position estimation of a sound source based on time difference of arrival at an array of three acousto-optic sensors is introduced. Each sensor consists of a Mach-Zehnder interferometer including a sensing part in one arm that is a piece of fiber surrounded by membrane in order to enhance the acousto-optic effect. Estimation error of a recorded gunshot sound signal was evaluated with the theoretically calculated values for two different locations.

• 한국군사과학기술학회지
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• 제16권4호
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• pp.566-574
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• 2013

In this paper, direct power control system for three-phase PFC AC/DC converter without the source voltage sensors is proposed. The sinusoidal input current and unity effective power factor are realised based on the estimated flux in the observer. Both active and reactive power calculated using estimated flux. The estimation of flux is performed based on the reduced-order virtual flux observer using the actual currents and the command control voltage. Moreover, source voltage sensors are replaced by a estimated flux. DC output voltage has been compensated by DC output ripple voltage estimation algorithm. The active and reactive powers estimation are performed based on the estimated flux and Phase angle. The proposed algorithm is verified through simulation and experiment.

• 에너지공학
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• 제13권4호
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• pp.296-300
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• 2004

본 연구는 지열원 물 대 물(water to water)히트 펌프 시스템의 냉방 및 난방 운전시 성능 특성과 경제성 평가에 관한 것이다. 5개의 보어홀당 지중 100m의 깊이로 밀폐 수직형 지중 열교환기(closed-vertical ground source)가 설치된 냉난방 시스템이 적용된 건축물에 대하여 냉난방 운전성능을 평가하였으며, 연간 소비전력을 측정하여 실제 시스템의 경제성을 분석하였다. 또한, 순환수의 입구온도에 따른 시스템의 운전 성능을 분석한 결과 난방시에는 COP가 3.0에서 4.2로 증가한 반면, 냉방시에는 5.0에서 3.7로 감소하였다. 본 실험을 통해서,대상 건축물에 대한 지열 냉난방 시스템의 수명주기비용은 기존 냉난방 시스템(보일러+에어컨)에 비해서 68%까지 절감되었으며, 시스템의 경제성을 고려해 볼 때 기존 건축물에도 지열원 냉난방 시스템을 적용하는 것이 타당하다.