• 한국통신학회논문지
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• 제32권3A호
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• pp.281-289
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• 2007

본 논문에서는 부호 분할 다중 접속 (code division multiple access: CDMA) 시스템에서 의사 잡음 부호 및 반전된 의사 잡음 부호의 획득이 가능하고 데이터 복조도 가능한 위상 변이 네트워크 기반의 차동 순차 추정 기법을 제안하였다. 모의실험을 통해 제안한 기법의 성능이 이제까지의 이중 상관 순차 추정 기법에 비해 낮은 복잡도를 가지면서도 동일한 성능을 지니고 있음을 보였다.

• 응용통계연구
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• 제32권5호
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• pp.741-752
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• 2019

제1상 임상시험의 주목적은 최대허용용량(maximum tolerated dose; MTD)을 결정하는 것이다. MTD 결정을 통해 다음 임상시험에 사용될 용량이 제한되므로 투약용량 발견 시험이라고도 불리며 매우 중요한 단계이다. MTD를 결정하는 방법에는 대표적으로 DM 방법, SM 방법, CRM 방법이 있다. 본 논문에서는 기존 수정된 CRM 방법에 초기가속화 단계를 적용하여 낮은 용량에 다수의 피험자가 할당되는 문제점을 보완하는 새로운 MTD 추정 방법을 제안하였고 기존 방법들과의 비교를 위해 모의실험을 실시하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 학술대회 논문집 전문대학교육위원
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• pp.80-85
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• 2001

Frequency is an important operating parameter of a power system. Frequency of a power system remains constant if sum of all the loads plus losses equals total generation in the system. However, the frequency starts to decrease if total generation is less than the sum of loads and tosses. On the other hand, the system frequency increases if total generation exceeds the sum of loads and losses. Electric power systems sustain transient frequency swings whenever the balance between generation and load does not no longer hold. To cope with this Constraints, it requires an accurate and high speedy frequency deviation estimation technique and suitable adjustment to obtain the power system energy balance. The fundamental frequency component of 3-phase signal is first extracted by using an algorithm based on FIR(finite duration impulse response) filter, a phase angle of a voltage. The rate change of the phase angle is used for estimation and speed in its process. Also, to confirm the validity of the proposed algorithm, the simulation results obtained by using EMTP(electro magnetic transients program) are shown.

• Journal of electromagnetic engineering and science
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• 제1권1호
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• pp.105-111
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• 2001

This paper presents a new and robust technique for a coarse frequency offset estimation in OFDM systems. As an evaluation of the proposed algorithm, we apply it to Eureka 147 DAB system. The proposed coarse frequency offset estimation algorithm is based on the differential detection technique between adjacent subcarriers to eliminate the phase shift effects of symbol timing offset and fractional frequency offset. A coarse frequency offset is determined from the correlation output between a received interarrier differential phase reference symbol and several locally generated but frequency-shifted intercarrier differential phase reference symbols. The performance of our estimation algorithm is evaluated by means of computer simulation and is compared with those of previous proposed algorithms for DAB transmission modes I, II, III, and IV. Simulation results show that the proposed algorithm generates extremely accurate estimates with low complexity irrespective of the symbol timing offset.

• 한국산학기술학회논문지
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• 제6권4호
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• pp.349-354
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• 2005

컴퓨터 비전에 관한 연구는 인간의 시각 능력을 대신할 시스템을 구축하고자 하는 것으로 특히 이동 객체추적 시스템은 최근 중요한 연구 분야로 대두되고 있다. 본 연구에서는 움직임 추정에 기반 한 단일 이동객체를 추적할 수 있는 시스템을 제안하였다. 추적 시스템은 차영상 기법을 이용하여 객체의 움직임을 추정하곤 카메라의 Pan/Tilt를 제어함으로서 이동 객체를 추적할 수 있도록 하였다. 구현된 시스템은 영상획득 및 전처리 단계, 움직임 추정 단계, 객체 추적 단계로 구성하였다. 실시간 추적 실험을 실시한 결과 이동 객체의 움직임을 추정할 수 있었고, 추적 과정에서도 객체를 일어버리지 앉고 정상적으로 추적할 수 있었다.

• 한국음향학회지
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• 제26권6호
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• pp.276-285
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• 2007

본 논문에서는 현재까지 주파수 영역에서 개발된 4종류의 라우드스피커 TS 매개변수 규명법들에 대하여 비교 검토하였다. 보이스 코일 인덕터에 대한 상세한 모델링을 위해 주파수 종속 모델링 기법을 소개하였고 관련된 매개변수들을 유도하였다. 라우드스피커의 동적 질량을 알고 있을 때에 TS 매개변수를 규명하는 방법을 소개하고 이를 실제 라우드스피커에 적용할 때에 고려할 사항들도 기술하였다. 1채널 장비로 전기 임피던스를 측정할 때에는 크기만을 측정하게 되므로 위상값 추정을 위해 최소 위상 변환법을 사용하는 방법도 기술하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.443-446
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• 2002

In this paper, a phase difference of liveline insulator was measured and analyzed to estimate the contamination degree. The probability of accident rises according to the increase of the contamination. So the estimation of contamination degree is very important in design and maintenance of outdoor insulator. There are many methods to measure the contamination degree, but those methods use the spacial sense to measure the contamination degree. So, we have no information about the contamination from the liveline insulator, but there is a measurement of phase difference to estimate the contamination degree. The phase difference is varied with the increase of ESDD, so the contamination degree could be estimated by using those characteristics. The experiment is performed to analyze the interrelationship between contamination degree and phase difference. The variable condition is relative humidity that increases from 30 to 100 % in a chamber. We use the DAS program to measure and analyze the data. From the result, the variation of phase difference is different by the contamination degree, so we can confirm the possibility of estimating the contamination degree by the phase difference.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1694-1700
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• 2004

In this paper, we propose the AWLS/MFT (Adaptive Weighed Least Squares/ Modulation Function Technique) devised by A. E. Pearson et al. for the transfer function estimation of a modal system and investigate the performance of several algorithms, the Gram matrix method, a Luenberger Observer (LO), Least Squares (LS), and Recursive Least Squares (RLS), for the estimation of initial conditions. With the benefit of the Modulation Function Technique (MFT), we can separate the estimation problem into two phases: the transfer function parameters are estimated in the first phase, and the initial conditions are estimated in the second phase. The LO method produces excellent IC estimates in the noise free case, but the other three methods show better performance in the noisy case. Finally, we compared our result with the Prony based method. In the noisy case, the AWLS and one of the three methods - Gram matrix, LS, and RLS- show better performance in the output Signal to Error Ratio (SER) aspect than the Prony based method under the same simulation conditions.

• IEIE Transactions on Smart Processing and Computing
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• 제3권4호
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• pp.240-245
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• 2014

How well the self-interference cancellation (SIC) technique performs is a primary issue in realizing an in-band full-duplex (FD) wireless communication system. One factor affecting its performance is channel estimation error on the self-interference channel. We propose a new analog SIC scheme which is robust to channel estimation error. It uses phase rotators in the radio frequency (RF) chain. We also derive closed-form equations for the residual self-interference of the proposed and the conventional schemes. The analytical and numerical results show that the residual self-interference under the proposed SIC scheme is less than that using the conventional scheme, even though channel estimation error is present.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 추계학술대회 논문집
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• pp.113-118
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• 2003

The proposed rotor time constant estimation method can be applied to the direct vector control system of induction motor with flux observer In this paper the flux observer proposed by Gopinath model are used. This paper presents a new scheme for on-line estimation of rotor time constant using estimated rotor flux phase and current model rotor flux phase. The major advantage of this method are its dynamic correction capability, simplicity and accuracy as well as independence from change in motor parameter. simulation results are presented which demonstrate the effectiveness of the on line rotor time constant estimation.