• Journal of Electrical Engineering and Technology
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• 제11권4호
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• pp.1020-1026
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• 2016

Motion estimation (ME) algorithms supporting quarter-pixel accuracy have been recently introduced to retain detailed motion information for high quality of video in the state-of-the-art video compression standard of H.264/AVC. Conventional sub-pixel ME algorithms in the spatial domain are faced with a common problem of computational complexity because of embedded interpolation schemes. This paper proposes a low-complexity sub-pixel motion estimation algorithm in the transform domain utilizing shifting matrix. Simulations are performed to compare the performances of spatial-domain ME algorithms and transform-domain ME algorithms in terms of peak signal-to-noise ratio (PSNR) and the number of bits per frame. Simulation results confirm that the transform-domain approach not only improves the video quality and the compression efficiency, but also remarkably alleviates the computational complexity, compared to the spatial-domain approach.

• 대한전자공학회논문지SP
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• 제45권5호
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• pp.52-62
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• 2008

본 논문에서는 임의의 블록 변환 영역에서 영상의 특성에 적절한 필터를 사용하여 영상의 해상도를 변환하는 기법을 개발 한다. 이를 위하여 임의의 직교 transform 영역에서 해상도 변환을 수행하는 모든 과정을 matrix 곱으로 표현하여 해상도 변환을 수행하는 matrix를 유도한다. 해상도 변환을 수행하는 matrix는 영상 특성에 알맞은 필터를 선택하여 사용할 수 있도록 설계한다. 개발된 기법은 다양한 transform 영역에 적용할 수 있고, 동영상 부호화시 발생되는 inter/intra block들이 혼합되어 있는 영상의 해상도 변환에 적용 가능함을 실험을 통하여 검증하였다.

• 한국통신학회논문지
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• 제33권11C호
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• pp.917-924
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• 2008

공간 영역에서의 움직임 예측은 이전 영상에서 지정된 크기의 탐색 영역을 검색하여 현재 블록과 최소 오차를 갖는 블록을 찾는 방법으로, 탐색 영역을 검색하는 과정에서 많은 부호화 시간이 소비된다. 이러한 문제점은 공간 영역에서의 움직임 예측을 주파수 영역에서의 이동 행렬을 사용함으로써 해결할 수 있다. 본 논문에서는 기존의 이동 행렬을 새로운 재귀방정식으로 유도하여 계산량을 줄이는 동시에 영상의 화질은 기존 방식과 유사하게 유지하고자 한다. 또한 반화소 정밀도의 움직임 예측을 위하여 주파수 영역에서의 수직, 수평 이동 행렬을 간단히 수정함으로써 공간 영역에서의 양선형 보간법에 의해 더욱 증대되는 계산량 문제를 해결하고자 한다. 실험 결과 제안된 알고리듬에 의한 DCT 기반 주파수 영역에서의 움직임 예측이 공간 영역에 비하여 적은 비트량을 이용하여 보다 높은 PSNR을 제공함으로 증명한다.

• 생명과학회지
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• 제8권3호
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• pp.235-240
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• 1998

Matrix metalloproteinases(MMP)는 배발생 및 재조직화 등의 정상적인 생체형성과 관절염, 암전이, 치근막염, 골조송증 등의 질병과정에서 collagen이나 proteoglycan과 같은 세포외기질의 구성성분을 분해하는 아연(zinc)효소군이다. 지금까지 다양한 종에서 mmp의 유전자가 클로닝되고 그 기능이 연구되어 왔지만 아직 어류에서는 연구결과가 보고된 바가 없다. 본 연구에서는 한국의 부산연안에 많은 연골어유 투툽상어(Scylliorhinus toraxzame)로부터 RT-PCR(reverse transcriptase dependent polymerase chain reaction)의방법으로 mmp cDNA의 일부를 클로닝하였다. 이것은 염기서열에서 인간, 쥐 및 닭의 membrane type matrix matalloproteinase-3(mt3-mmps)의 염기서열과 74% 동일성을 보이며, 아미노산서열에서는 90%이상의 동일성을 갖고 있다. 또한 MMP에 나타나는 cysteine switch domain, zinc binding domain(HExGH motif), propeptide cleavage site, and RRKR motif등을 가지고 있다. 이러한 결과로부터 본 연구에서 클로닝된 RT-PCR단편은 두툽상어의 mt3-mmp 또는 이와 유사한 유전자의 cDNA이라 믿어진다.

• 한국전산유체공학회지
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• 제2권1호
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• pp.21-28
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• 1997

This paper presents a two-dimensional horizontal implicit model to general circulation in estuaries and coastal seas. The model is developed in non-orthogonal curvilinear coordinates system, using the Interpolating Matrix Method (IMM), in combination with a technique of multi-domain. In the propose model, the Saint-Venant equations are solved by a splitting-up technique, in the successive steps; convection, diffusion and wave propagation. The ability of the proposed model to deal with full scale nature is illustrated by the interpretation of a dye-tracing experiment in the Gironde estuary.

• 전자공학회논문지A
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• 제32A권9호
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• pp.1244-1249
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• 1995

Wavelet transform technique is applied to two important electromagnetic problems:1) to analyze the frequency-domain radar echo from finite-size targets and 2) to the integral solution of two- dimensional electromagnetic scattering problems. Since the frequency- domain radar echo consists of both small-scale natural resonances and large-scale scattering center information, the multiresolution property of the wavelet transform is well suited for analyzing such ulti-scale signals. Wavelet analysis examples of backscattered data from an open- ended waveguide cavity are presented. The different scattering mechanisms are clearly resolved in the wavelet-domain representation. In the wavelet transform domain, the moment method impedance matrix becomes sparse and sparse matrix algorithms can be utilized to solve the resulting matrix equationl. Using the fast wavelet transform in conjunction with the conjugate gradient method, we present the time performance for the solution of a dihedral corner reflector. The total computational time is found to be reduced.

• Journal of Power Electronics
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• 제14권3호
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• pp.572-579
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• 2014

As a non-linear time variant system, the four-quadrant line converter of an electric multiple unit (EMU) was expressed by linear time periodic functions near an operating point and modeled by a steady-state harmonic domain matrix. The components were then combined according to the circuit connection and relations of the feedback control loops to form a complete converter model. The proposed modeling method allows the study of the amplitude of harmonic impedances to explore harmonic coupling. Moreover, the proposed method helps provide a better design for the converter controllers, as well as solves the problem in coordination operation between the EMUs and the AC supply. On-site data from an actual $CRH_2$ high-speed train were used to validate the modeling principles presented in the paper.

• Smart Structures and Systems
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• 제26권4호
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• pp.419-433
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• 2020

Investigation of structural integrity has been a critical issue in the field of civil engineering for years. Visual inspection is one of the most available methods to explore deteriorative components in structures. Still, this method is not applicable to invisible damage of structures. Alternatively, system identification methods are capable of tracking modal properties of structures over time. The deviation of these dynamic properties can serve as indicators to access structural integrity. In this study, a modal tracking technique using frequency-domain system identification from seismic responses of structures is proposed. The method first segments the measured signals into overlapped sequential portions and then establishes multiple Hankel matrices. Each Hankel matrix is then converted to the frequency domain, and a temporal-average frequency-domain Hankel matrix can be calculated. This study also proposes the frequency band selection that can divide the frequency-domain Hankel matrix into several portions in accordance with referenced natural frequencies. Once these referenced natural frequencies are unavailable, the first few right singular vectors by the singular value decomposition can offer these references. Finally, the frequency-domain stochastic subspace identification tracks the natural frequencies and mode shapes of structures through quick stabilization diagrams. To evaluate performance of the proposed method, a numerical study is carried out. Moreover, the long-term monitoring strong motion records at a specific site are exploited to assess the tracking performance. As seen in results, the proposed method is capable of tracking modal properties through seismic responses of structures.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.44-48
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• 2009

This paper develops a methodology for resizing image resolutions in an arbitrary block transform domain. To accomplish this, we represent the procedures resizing images in an arbitrary transform domain in the form of matrix multiplications from which the matrix scaling the image resolutions is produce. The experiments showed that the proposed method produces the reliable performances without increasing the computational complexity, compared to conventional methods when applied to various transforms.

• 전자공학회논문지B
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• 제32B권9호
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• pp.1188-1197
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• 1995

This paper describes an algorithm that reduces computational requirement of the Kalman filter and estimates the signal efficiently. The reference signals are mapped onto the orthogonal wavelet transform domain so that the eigenvalue spread of its autocorrelation matrix could be smaller than that in the time domain. In the wavelet transform domain the autocorrelation matrix is nearly diagonal. Therefore, the transformed signal can be decomposed each orthogonal elements. The Kalman filter can be applied to each orthogonal elements and computational requirement is reduced. The possibility of applying the parallel Kalman filter was verified through the theory and simulation. The eigenvalue spread in the wavelet transform domain is smaller 8.35 times than that in the time domain and the computational requirement is reduced from 1.4 times to 2. 93 times than that of the conventional Kalman filter.