• Proceedings of the Korea Contents Association Conference
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• 2016.05a
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• pp.457-458
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• 2016

KLT 알고리즘은 자기상관성을 이용하여 선정한 물체의 모서리(conner)를 추적할 특징으로 삼는데, 여기서 사용할 모서리를 검출하는 데는 Harris 방법이 많이 쓰인다. 해리스 방법에서는 강도(intensity)의 미분치를 평활화(smoothing)한 후 고유치를 구해서 모서리인지 에지인지를 판별하게 되는데, 본 논문에서는 평활화가 모서리검출의 성능에 미치는 영향을 밝힌다.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.953-954
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• 2004

• Magazine of the Korea Concrete Institute
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• v.6 no.3
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• pp.180-189
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• 1994

An approximate method of normal coordinate idealization for use in nonlinear R /C frames has been developed. Normal coordinate apporaches have been used for nonlinear problems in the past, but they are not recerved wide acceptance because of the need for eigenvector computation in each time step. The proposed method circumvents the eigenvector recalculation problem by evaluating a limited number of sets of mode shapes in performing the dynamic analysis. Then some of the predetermined sets of eigenvectors are used in the nonlinear dynamic repeatedly. The method is applied to frame structures with ductile R /C elements. The plastic hinge zones are modeled with hysteres~s loops which evince degrading stiffness and pinching effects. Effxiencies and accuracies of the method for this application are presented.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.335-338
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• 2001

잔향음은 시변동성이 존재하는 유동성 경계면 잔향음(해수면, 체적)과 시변동성이 존재하지 않는 고정 경계면 잔향음(해저면)으로 분류된다. 그러나 고정 경계면 잔향음으로 알려진 해저면 잔향음에서도 단주기적 시변동성이 존재하고 있음이 여러 실측자료에서 관측되고 있다. 본 연구는 시변동성의 원인을 파악하고자 실험실에서 부유성 퇴적물의 농토에 따른 후방산란 신호를 측정하였다. 또한 동해에서 측정된 시간에 따른 잔향음신호(80kHz)와 ADCP(4.2MHz) 자료를 비교하여 천해에서의 체적 산란체의 변동이 잔향음 신호에 영향을 미칠 수 있음을 확인하였다. 아울러 본 논문에서는 잔향음 신호의 단주기적 시변동성에 의한 잡음 성분을 제거하여 표준화된 잔향음 신호를 획득하기 위한 방법으로 Low Rank Approximation(LRA)을 제안하였다. 이 기법은 특이해 분해(Singular Value Decomposition, SVD)를 수행하여 실측 자료 행렬로부터 고유치(Eigenvalue)과 고유벡터(Eigenvector)를 추출한 후, 추출된 고유치를 제한적으로 사용하여 근사화 하는 기법으로 시변동성 신호를 제거하는데 효율적인 방법이다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.6
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• pp.683-689
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• 2014

The present study conducted a parameter effect analysis of low-frequency squeal noise using a numerical simulation. The finite element program ABAQUS was used to calculate the dynamic instability based on a complex eigenvalue analysis. A total of five parameters, including the chassis, wear, piston, material property, and contact condition, were selected to identify the factor effects on a low-frequency squeal noise between 2.5 and 3.1 kHz. The present study found the dominant level of each factor through an analysis of the means in the context of the experiment design.

• Journal of the Earthquake Engineering Society of Korea
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• v.16 no.4
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• pp.19-26
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• 2012

For a seismic design or performance evaluation of a structure, an experimental investigation on a scale model of the structure or numerical analysis based on the finite element model is considered. Regarding the numerical analysis, a three-dimensional finite element analysis is performed if a high accuracy of the results is required, while a sensitivity or fragility analysis which uses huge seismic ground motions leads to the use of a lumped-mass stick model. The conventional modeling technique to build the lumped-mass stick model calculates the amount of the lumped mass by considering the geometric shape of the structure, like a tributary area. However, the eigenvalues of the conventional model obtained through such a calculation are normally not the same as those of the actual structure. In order to overcome such a deficiency, in this study, a new lumped mass stick model is proposed. The model is named the "frequency adaptive-lumped-mass stick model." It provides the same eigenvalues and similar dynamic responses as the actual structure. A non-prismatic column is considered as an example, and its natural frequencies as well as the dynamic performance of the new lumped model are compared to those of the full-finite element model. To investigate the damping effect on the new model, 1% to 5% of the critical damping ratio is applied to the model and the corresponding results are also compared to those of the finite element model.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.10
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• pp.700-707
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• 2014

In this paper, we propose the noise reduction method by using the eigenfilter in cyclic prefix system based on SNR. To obtain the signal eigenvectors for the eigenfiltering, we propose a method of obtaining the autocorrelation matrix by exploiting the circulant property of the received block which results from the cyclic extension of the OFDM symbol. Since the structures of the transmitter and the receiver are not changed, the proposed method is easy to apply to the conventional OFDM system. To verify the proposed method, we evaluate the persistency of excitation (POE) criterion for the input and demonstrate the effectiveness of the proposed method in the simulation results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.12
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• pp.2303-2312
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• 1994

A high resolution algorithm is presented for resolving multiple narrowband plane waves that are incident on an equispaced linear array. To overcome the deleterious effects due to coherent sources, a number of noise-eigenvector-based approaches have been proposed for narrowband signal processing. For differing reasons, each f these methods provide a less than satisfactory resolution of the coherency problem. The proposed algorithm makes use of fundamental property possessed by those eigenvectors of the spatial covariance matrix that are associated with eigenvalues that are larger than the sensor noise level. This property is then used to solve the incoherent and coherent sources incident on an equispaced linear array. Simulation results are shown to illustrate the high resolution performance achieved with this new approach relative to that obtained with MUSIC and spatial smoothed MUSIC.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.2 s.344
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• pp.18-23
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• 2006

In this paper, we derive a novel eigenvalue equation of double silica layers on silicon only for TE mode and present the method as an example how to use it to determine the refractive indices and thicknesses with prism coupler. Our method to solve eigenvalue equation have good merit rather than [5] in that the equation is real and iteration parameters can be reduced from four to three. The average magnitude of the errors is less than $10^{-5}\~10^{-6}$ approximately

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.5
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• pp.976-983
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• 1988

An efficient unbalance response analysis method for rotor-bearing systems with spin speed dependent parameters is developed by utilizing a generalized modal analysis scheme. The spin speed dependent eigenvalue problem of the original system is transformed into the spin speed independent eigenvalue problem by introducing a lambda matrix, assuming the bearing dynamic coefficients are well approximated by polynomial functions of spin speed. This method features that it requires far less computational effort in unbalance response calculations and that the influence coefficients are readily available. In addition, the critical speeds and the corresponding logarithmic decrements can be readily identified from the resulting eigenvalues.