• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.14-15
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• 2013

본 논문에서는 공간 계층 분해를 이용한 3 차원 메쉬 시퀀스 압축 기법을 제안한다. 제안하는 기법은 우선 각 점에 대한 시간적 궤적을 공분산 행렬로 표현하고, PCA(Principal component analysis)를 적용하여 시간 궤적에 대한 고유 벡터와 PCA 계수를 획득한다. 공간적인 예측을 통해 PCA 계수에 대한 벡터 차를 추출하고, 벡터 차와 그것에 대한 고유 벡터를 전송한다. 제안하는 방법은 PCA 계수 예측의 성능을 높이기 위해 점진적 압축에서 사용하는 공간 계층 분해 기법을 적용하여, 계수 예측에 효과적인 이웃 점을 지정하도록 한다. 또한, 이웃 점 개수를 사용자가 임의로 지정할 수 있도록 하여, 성능과 복잡도간의 트레이드 오프를 제어할 수 있도록 한다. 다양한 모델에 대한 실험 결과를 통해 제안하는 방법의 성능을 확인한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.9
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• pp.848-855
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• 2004

In this paper, we propose a new channel identification technique for long code DS/CDMA DMB down link system which estimate the channel response based on the signal space vector only, unlike the most conventional subspace method relying on the orthogonal property of noise space vectors to the signal space vector. Because of this property of the proposed method, it is optimum and practical in manipulation of the covariance matrix to be analyzed. In the paper, we derive the mathematical expression necessary to clarify the proposed method and show the relevant simulation and numerical results to verify the validity of the proposed algorithm.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.1
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• pp.77-86
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• 2002

This paper proposes a modified Duvall beamformer performing spatial smoothing with spatial interpolation. In the proposed beamformer, virtual array signals are generated by spatial interpolation between each neighbor array elements, then all signals are used to perform spatial smoothing. The proposed beamformer overcomes the loss of degrees of freedom caused by spatial smoothing by forming subarrays with interpolated signals. Mathematical description shows that the proposed beamformer can restore the rank of away covariance matrix. Accordingly, the proposed beamformer can minimize the loss of degrees of freedom. Simulation results show that the proposed beamformer can remove all coherent interferences while conventional beamformers cannot.

• The Journal of the Acoustical Society of Korea
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• v.36 no.2
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• pp.100-107
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• 2017

The focused MVDR (Minimum Variance Distortionless Response) can be applied for source localization in near field. However, if the number of sensors are increased, it requires a large amount of calculation to obtain the inverse of the covariance matrix. In this paper we propose a focused MVDR method using that beam space is formed from output of far field beamformer at the subarray. The performances of the proposed method was evaluated by simulation. As a result of simulation, the proposed method has the higher spatial resolution performance then the conventional delay-and-sum beamformer.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.4
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• pp.333-339
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• 2017

Transmission signal in wireless environment receives a signal in which a source signal, interference, and noise are mixed. The goal of this study is to estimate the desired signal from the received signal. In this paper, we have studied a method correctly estimating a target in spatial by modified beamformer method. The modified bemaformer uses an adaptive array antenna and perturbation matrix to obtain the optimal weight, and estimate the desired signal by radiating the beam in spatial. We estimate a desired signal of the target by improving resolution with the modified beamformer method which does not have complicated calculation amount. Through simulation, we compare and analyze the modified beamformer method and the MUSIC method with good resolution. In result of simulation, we showed that modified beamformer method has better resolution of 10degree than classical beamformer method and showed similar performance as the MUSIC method. The resolution of this paper was estimated to be about 5 degrees.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2003.04a
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• pp.94-99
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• 2003

다중분광 영상의 정확한 지형지물 분류를 수행하기 위하여 분류 클래스의 훈련지역 선정과 선정된 클래스의 분리도 분포가 중요하다. 최근에 이용되고 있는 위성탑재 초다중분광 영상은 많은 밴드를 포함하고 있기 때문에 데이터 처리가 어렵고, 노이즈로 인하여 다중분광 영상보다 분류 결과가 나쁜 경우도 나타난다. 특히 대상지역의 클래스에 따른 훈련지역의 선정시 밴드수에 비해 상대적으로 제한된 훈련화소 크기로 인하여 공분산 행렬의 계산에 어려움이 따른다. 따라서 본 연구에서는 Hyperion 데이터를 이용한 분류를 수행하기 위하여 필요한 유효 밴드 추출 방식을 알아보고, 분류영상의 정확도 평가를 통하여 추출된 밴드와 분류 클래스의 적합성 관계를 확인하고자 한다 이 과정에서 클래스 분리도를 이용하여 정확도 평가 이전에 밴드와 클래스 선정의 타당성을 확인할 수 있다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.5
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• pp.400-404
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• 2015

In this paper, we study for direction of arrival MUSIC spatial spectrum algorithm in order to desired signal estimation in spatial. Proposal MUSIC spatial spectrum algorithm in paper use model error and Bayesian method to estimation on correct target position. Receiver array response vector using adaptive array antenna use Bayesian method, and target position estimate to update weight value with model error method. Target's signal estimation of desired direction of arrival in this paper apply weight value of signal covariance matrix for array response vector after removing incident signal interference and noise, respectively. Though simulation, we analyze to compare proposed method with general method.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.6
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• pp.162-170
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• 2010

Adaptive arrays reject interferences while preserving the desired signal, exploiting a priori information on its arrival angle. Subspace-based adaptive arrays, which adjust their weight vectors in the signal subspace, have the advantages of fast convergence and robustness to steering vector errors, as compared with the ones in the full dimensional space. However, the complexity of theses subspace-based methods is high because the eigendecomposition of the covariance matrix is required. In this paper, we present a simple subspace-based method based on the PASTd (projection approximation subspace tracking with deflation). The orignal PASTd algorithm is modified such that eigenvectora are orthogonal to each other. The proposed method allows us to significantly reduce the computational complexity, substantially having the same performance as the beamformer with the direct eigendecomposition. In addition to the simple beamforming method, we present theoretical analyses on the SINR (signal-to-interference plus noise ratio) of subspace beamformers to see their behaviors.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.89-93
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• 2013

This paper is estimating a target direction of arrival with incident to receiver in spatial. This paper presented covariance using constraint matrix to correlation interference signal cancellation in multi input multi output array antennas system. we proposed a target direction of arrival estimation algorithm using cost function and minimum variance method. Through simulation, we were analysis a performance to compare general SPT-LCMV algorithm and proposal algorithm. We showed that proposal algorithm improve more target estimation than general SPT-LCMV algorithm in direction of arrival.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.5
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• pp.133-138
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• 2010

In this paper, we make up a feature image including spatial properties and statistical properties on image, and format covariance matrices using region variance magnitudes. By using it to texture classification, this paper puts a proposal for tough texture classification way to illumination, noise and rotation. Also we offer a way to minimalize performance time of texture classification using integral image expressing middle image for fast calculation of region sum. To estimate performance evaluation of proposed way, this paper use a Brodatz texture image, and so conduct a noise addition and histogram specification and create rotation image. And then we conduct an experiment and get better performance over 96%.