• 한국통신학회논문지
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• 제11권6호
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• pp.388-395
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• 1986

Spectral domain에서 hybrid mode 분석과 Galerkin method를 사용하여 차폐된 단일, 결합 및 edge-offset 마이크로 스트립 구조의 분산특성을 고찰하였다. 진행방향의 스트립 전류에 대한 새로운 2개의 basis function이 제안되었으며 그들을 사용한 수치해의 수렵속도를 비교하였다. 결합 마이크로 스트립의 전류분포는 단일 마이크로 스트입의 전류분포로부터 Fourier변환의 shift theorem을 이용하여 얻었으며 off-centered 스트립의 분산에 대한 영향이 논의되었다. 수치 결과들은 여러가지 구조 parameter 들을 포함하여 다른 유용한 data 들과 비교한 결과 잘 일치함을 알 수 있었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권11호
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• pp.5513-5529
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• 2016

Doppler Effect is a prominent obstacle in vehicular networks, which dramatically increase the Bit-Error-Rate (BER). This problem is accompanied with the presence of the Orthogonal Frequency Division Multiplexing (OFDM) systems in which the Doppler shift interrupts the subcarriers orthogonality. Additionally, Inter-Symbol Interference (ISI) and high Peak-to-Average Power Ratio (PAPR) are likely to occur which corrupt the received signal. In this paper, the single-carrier combined with the frequency domain equalizer (SC-FDE) is utilized as an alternative to the OFDM over the IEEE 802.11p uplink vehicular channels. The Minimum Mean Squared Error (MMSE) and Zero-Forcing (ZF) are employed in order to study the impact of these equalization techniques along with the SC-FDE on the propagation medium. In addition, we aim to enhance the BER, improve the transmitted signal quality and achieve ISI and PAPR mitigation. The proposed schemes are investigated and we found that the MMSE outperforms the ZF equalization under different Doppler shift effects and modulations.

• 대한원격탐사학회지
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• 제23권5호
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• pp.421-430
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• 2007

This paper presents the results of the ocean surface current velocity estimation using 6 Radarsat-1 SAR images acquired in west coastal area near Incheon. We extracted the surface velocity from SAR images based on the Doppler shift approach in which the azimuth frequency shift is related to the motion of surface target in the radar direction. The Doppler shift was measured by the difference between the Doppler centroid estimated in the range-compressed, azimuth-frequency domain and the nominal Doppler centroid used during the SAR focusing process. The extracted SAR current velocities were statistically compared with the current velocities from the high frequency(HF) radar in terms of averages, standard deviations, and root mean square errors. The problem of the unreliable nominal Doppler centroid for the estimation of the SAR current velocity was corrected by subtracting the difference of averages between SAR and HF-radar current velocities from the SAR current velocity. The corrected SAR current velocity inherits the average of HF-radar data while maintaining high-resolution nature of the original SAR data.

• 한국자기공명학회논문지
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• 제21권1호
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• pp.20-25
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• 2017

The cytoplasmic domains A and B of the mannitol transporter enzyme $II^{Mtl}$ are covalently linked in Escherichia coli, but separately expressed in Thermoanaerobacter Tengcongensis. The phosphorylation of domain B ($TtIIB^{Mtl}$) substantially increases the binding affinity to the domain A ($TtIIA^{Mtl}$) in T. Tengcongensis. To understand the structural basis of the enhanced domain-domain interaction by protein phosphorylation, we obtained NMR backbone assignments of the phospho-$TtIIB^{Mtl}$ using a standard suite of triple resonance experiments. Our results will be useful to monitor chemical shift changes at the active site of phosphorylation and the binding interfaces.

• BMB Reports
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• 제35권3호
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• pp.343-347
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• 2002

The human protein tyrosine kinase-6 (PTK6) polypeptide that is deduced from the cDNA sequence contains a Src homology (SH) 3 domain, SH2 domain, and catalytic domain of tyrosine kinase. We initiated biochemical and NMR characterization of PTK6 SH3 domain in order to correlate the structural role of the PTK6 using circular dichroism and heteronuclear NMR techniques. The circular dichroism data suggested that the secondary structural elements of the SH3 domain are mainly composed of $\beta$-sheet conformations. It is most stable when the pH is neutral based on the pH titration data. In addition, a number of cross peaks at the low-field area of the proton chemical shift of the NMR spectra indicated that the PTK6 SH3 domain retains a unique and folded conformation at the neutral pH condition. For other pH conditions, the SH3 domain became unstable and aggregated during NMR measurements, indicating that the structural stability is very sensitive to pH environments. Both the NMR and circular dichroism data indicate that the PTK6 SH3 domain experiences a conformational instability, even in an aqueous solution.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.117-119
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• 2006

In this work, we suggest another method to localize DFT in spatial domain. This enables DFT algorithm to be used for local pattern matching. Once calculated, it costs same load to calculate localized DFT regardless of the size or the position of local region In spatial domain. We applied this method to face detection problem and got the results which prove the utility of our method.

• 한국기계연구소 소보
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• 통권18호
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• pp.87-97
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• 1988

The algorithm for relation of contact status, track shift, and contact force caused from wheel/rail contact geometry is presented. Grafting this algorithm into a algorithm of general program analyzing mechanical system, the program for time domain simulation of railway vehicle dynamics, called CASOTD, was developed. In addition, as applied example of CASOTD, the dynamic simulation of railway vehicle running on a rail joint and a irregularly alinemented rail is done in this paper.

• 한국멀티미디어학회논문지
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• 제6권5호
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• pp.816-823
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• 2003

이 논문에서는 토널 특성을 이용한 브라인드 오디오 워터마킹을 제안한다. 먼저 기존의 심리음향연구를 통해 토널의 인지영향에 대해 살펴보고, 토널 성분이 여러 신호처리 후 변동측면에서 매우 안정적인 특성을 가짐을 다른 워터마크에 이용되는 특성들과 비교하여 보였다. 이를 기반으로 토널 마스커를 구성하는 주파수 신호들의 관계를 이용한 브라인드 오디 오 워터마킹(blind audio watermarking) 기법을 제안하였다. 이 기법이 적용된 오디오에 대한 SDG(Subjective Diff-Grades) 음질평가에서 평균 SDG 0.27의 결과를 얻었고 이는 비지각성 면에서 토널의 인지 영향을 이용한 워터마킹이 유용하다고 볼 수 있다. 또한 time shift를 제외한 여러 신호처리 후의 워터마크 추출 결과는 98%이상으로 제안한 워터마킹의 강인성을 보였다. Time shift처리에 대해서는 시간 축 상에서 최적의 위치를 찾아 추출하는 새로운 방법을 적용하여 추출율 90%의 결과를 얻었다.

• 한국통신학회논문지
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• 제28권2C호
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• pp.110-120
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• 2003

본 논문에서는 웨이블릿 변환 영역에서 저대역 이동법에 적합한 다해상도 움직임 추정을 제안하였다. 저대역 이동법(Low Band Shift Method)은 웨이블릿 계수들의 이동-변환 성질을 극복하기 위하여 제안된 방법으로 동영상 부호화시 참조 프레임에 적용하면 정확한 움직임 추정이 가능하여 일반적인 방법보다 압축대비 화질면에서 우수한 성능을 가지지만, 단점으로 메모리와 계산량이 일반적인 방법에 비해 많아지게 된다. 본 논문에서 제안된 방법(LBS-MRME)은 저대역 이동법에 적합한 다해상도 움직임 추정을 적용하여 3단계 웨이블릿 변환시 기존의 방법의 약 15.6%의 계산량으로 움직임 추정을 한다. 그리고 부호화시 움직임 벡터가 각 부대역마다 존재하게 되므로 움직임 벡터가 약 7배 늘어나게 되지만, 더 세밀한 움직임 추정을 할 수 있게 되므로 움직임 보상 예측 오차의 부호화량이 줄어들게 되어 부호화 효율이 기존의 방법보다 좋아지게 된다. 압축을 하지 않았을 경우 평균 MAD면에서 약 0.3∼11.6% 가량 개선되었고, 압축을 할 때 동일한 비트율에서 PSNR이 약 0.3∼3.0㏈ 정도 개선되었다.

• 한국자기공명학회논문지
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• 제22권3호
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• pp.64-70
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• 2018

Human Tid1, belonging to the family of the Hsp40/DnaJ, functions as a co-chaperone of cytosolic and mitochondrial Hsp70 proteins. In addition, the conserved J-domain and G/F-rich region of Tid1 has been suggested to interact with the p53 tumor suppressor protein, to translocate it to the mitochondria. Here, backbone NMR assignments were achieved for the putative p53-binding domain of Tid1. The obtained chemical shift information identified five ${\alpha}$-helices including four helices characteristic of J-domain, which are connected to a short ${\alpha}$-helix in the G/F-rich region via a flexible loop region. We expect that this structural information would contribute to our progressing studies to elucidate atomic structure and molecular interaction of the domain with p53.