• 한국항행학회논문지
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• 제23권5호
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• pp.444-451
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• 2019

본 논문에서는 항공기 탑재장비의 RS-170a 영상 신호에 대한 EMI 및 낙뢰 간접영향에 대한 보호 대책을 설명한다. 항공기 탑재장비는 외부 환경으로부터 발생하는 전자파 간섭과 항공기 낙뢰 피격시 발생하는 낙뢰 간접영향으로 부터 발생하는 서지 전압에 의해 장비의 오작동이나 물리적 손상의 위험에 노출되어있다. 이러한 위험으로부터 장비를 보호하기 위해서는 전자파 간섭 및 간접 낙뢰 효과에 대한 보호 설계를 장비에 적용해야 하는데, 신호의 전압이 낮고 주파수 대역이 높을수록 보호 회로에 의한 신호 왜곡이 문제가 된다. 따라서 본 논문에서는 EMI 및 낙뢰 간접영향에 대한 일반적인 보호 설계 방법과, RS-170a 신호를 기준으로 보호 설계 적용에 따른 영상 신호 왜곡 현상을 최소화하기 위한 고려 사항을 소개한다. 그리고 이 과정에서 논한 고려 사항을 적용해 실제 장비 설계를 개선한 사례를 소개한다.

• 한국항행학회논문지
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• 제26권2호
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• pp.78-84
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• 2022

본 논문에서는 다중 신호원이 존재하는 경우에 닫힌 형태 기반의 3차원 위치 추정 기법을 제안한다. TDOA나 AOA, FDOA와 같은 일반적인 위치 추정 기술은 단일 신호원이 존재하는 경우에 위치를 추정할 수 있으며, 미상의 다중 신호원이 존재하는 경우에 이를 구분하여 위치를 추정하는데 한계가 있다. 제안된 기법은 배열 안테나를 갖는 센서에 수신된 신호의 상호상관 벡터를 계산하고, 상호상관 값으로부터 TDOA값과 AOA값을 추정한다. 그리고 기준 센서의 위치를 이용하여 좌표 변환을 수행하고, 변환된 좌표에 대해 추정된 AOA값을 이용하여 좌표 회전을 수행한 후 각 신호원에 대한 3차원 위치를 추정한다. 제안된 기법은 컴퓨터 모의실험을 통해 그 성능을 검증한다.

• 한국발생생물학회지:발생과생식
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• 제25권3호
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• pp.133-143
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• 2021

In contrast to the human lutropin receptor (hLHR) and rat LHR (rLHR), very few naturally occurring mutants in other mammalian species have been identified. The present study aimed to delineate the mechanism of signal transduction by three constitutively activating mutants (designated M410T, L469R, and D590Y) and two inactivating mutants (D383N and Y546F) of the eel LHR, known to be naturally occurring in human LHR transmembrane domains. The mutants were constructed and measured cyclic adenosine monophosphate (cAMP) accumulation via homogeneous time-resolved fluorescence assays in Chinese hamster ovary (CHO)-K1 cells. The activating mutant cells expressing eel LHR-M410T, L469R, and D590Y exhibited a 4.0-, 19.1-, and 7.8-fold increase in basal cAMP response without agonist treatment, respectively. However, inactivating mutant cells expressing D417N and Y558F did not completely impaired signal transduction. Specifically, signal transduction in the cells expressing activating mutant L469R was not occurred with a further ligand stimulation, showing that the maximal response exhibited approximately 53% of those of wild type receptor. Our results suggested that the constitutively activating mutants of the eel LHR consistently occurred without agonist treatment. These results provide important information of LHR function in fish and regulation with regard to mutations of highly conserved amino acids in glycoprotein hormone receptors.

• KIEE International Transactions on Power Engineering
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• 제3A권3호
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• pp.139-147
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• 2003

The paper presents a novel approach of constructing the state matrix of the multi-machine power system for SSR (subsynchronous resonance) analysis using the linearized equations of individual devices including electrical transmission network dynamics. The machine models in the local d-q reference frame are integrated with the network models in the common R-I reference frame by simply transforming their output equations into the R-I frame where the transformed output is used as the input to the network dynamics or vice versa. The salient feature of the formulation is that it allows for modular construction of various component models without rearranging the overall state space formulation. This universal SSR small signal stability program provides a flexible tool for systematic analyses of SSR small-signal stability impacts of both conventional devices such as generation systems and novel devices such as power electronic apparatus and their controllers. The paper also presents its application results to IEEE benchmark models.

• Journal of electromagnetic engineering and science
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• 제5권3호
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• pp.132-139
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• 2005

Wireless bio-signal sensing system, which is based on the principle of Doppler radar, can measure a respiration and heart rates with a periodic movement of skin and muscle near the heart. Though the sensing monostatic system using a circulator has been studied, this bistatic system can be improved by using a circular polarized antenna which has a high isolation between transmitter and receiver. In this paper, we measured the bio-signal without the direct contact with the person. The design of each system and experimental results are discussed.

• ETRI Journal
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• 제30권3호
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• pp.461-468
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• 2008

This paper presents a chromatic dispersion monitoring technique using a clock-frequency component for carrier-suppressed return-to-zero (CSRZ) signal. The clock-frequency component is extracted by a clock-extraction (CE) process. To discover which CE methods are most efficient for dispersion monitoring, we evaluate the monitoring performance of each extracted clock signal. We also evaluate the monitoring ability to detect the optimum amount of dispersion compensation when optical nonlinearity exists, since it is more important in nonlinear transmission systems. We demonstrate efficient CE methods of CSRZ signal to monitor chromatic dispersion for optimum compensation in high-speed optical communication systems.

• Design & Manufacturing
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• 제9권2호
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• pp.1-5
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• 2015

Recently, as small-sized display products such as mobile phones and digital cameras have become lighter and smaller, the size of electric signal delivery part, connector for the mobile display products, also, needs to become smaller, so high-density integration like shortening the distance between signal delivery media, conductors is necessary. With the micro and high-density integration of the connector, it is necessary to maintain contact to a certain degree for keeping intensity and delivering electric signal smoothly to prevent a defect with a specific impact. Accordingly, this study carried out a structural analysis according to the operating mechanisms of 0.16CHP Class Bottom Contact FPC Connector and 0.24CHP Class BTB Connector mostly used in small-sized mobile display products such as mobile phones and digital cameras. As a result of the analysis, both connectors had lower than 997MPa, yield strength of connector material C5240-XSH, so it is judged that permanent plastic deformation would not occur, and that a contact force between the connector and FPC film occurs to a certain degree, so that there would not be any defect in electric signal delivery.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권5호
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• pp.2434-2453
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• 2019

To improve the separation performance of time-frequency overlapped radar and communication signals from a single channel, this paper proposes an effective separation method based on an improved empirical wavelet transform (EWT) that introduces a fast boundary detection mechanism. The fast boundary detection mechanism can be regarded as a process of searching, difference optimization, and continuity detection of the important local minima in the Fourier spectrum that enables determination of the sub-band boundary and thus allows multiple signal components to be distinguished. An orthogonal empirical wavelet filter bank that was designed for signal adaptive reconstruction is then used to separate the input time-frequency overlapped signals. The experimental results show that if two source components are completely overlapped within the time domain and the spectrum overlap ratio is less than 60%, the average separation performance is improved by approximately 32.3% when compared with the classic EWT; the proposed method also improves the suitability for multiple frequency shift keying (MFSK) and reduces the algorithm complexity.

• 한국정보전자통신기술학회논문지
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• 제1권1호
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• pp.7-12
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• 2008

본 논문에서는 심전도(ECG)에서 R-파의 추출을 어렵게 하는 기저선 변동의 최소화 방법을 연구하였다. 이 방법에서는 기저선의 변동을 최소화하기 위하여 심전도와 상승 기울기 추적파의 차신호를 이용하였다. 여기서 상승 기울기 추적파는 심전도 신호에서 기울기가 하강할 때는 그대로 심전도 신호를 추적하고 기울기가 상승할 때는 그 시작시간의 심전도 신호를 기준값으로 일정시간 유지시켜 준 후 다시 원신호를 추적하는 파형이다. 구현된 방법의 효용성을 검증하기 위하여 MIT/BIH 데이터 베이스의 심전도에 적용하여 그 실효성을 확인하였다.

• 한국컴퓨터정보학회논문지
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• 제19권8호
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• pp.107-117
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• 2014

본 논문에서는 심전도 파형에서 P, R, T-wave와 같은 local maxima 신호 영역과 Q, S-wave와 같은 local minima 신호영역을 제거하여 기저선 변동 잡음을 제거하기 위한 방법을 제시한다. 이를 위해 형태연산을 개선한 morphology-pair 연산을 심전도 파형에 적용하고, 그 결과 발생되는 돌출 파형을 제거하고자 중간 값 연산을 적용하였다. 제안한 알고리즘의 성능을 확인하기 위해 실제 심전도 임상 데이터인 MIT/BIH 데이터베이스를 이용하였으며, 실험 결과 원 신호를 왜곡 하지 않고, 기저선 변동 잡음을 효과적으로 제거함을 확인하였다.