• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.9
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• pp.993-1000
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• 2015

Mel-Frequency Cepstral Coefficients(: MFCC) is one of the noble feature vectors for speech signal processing. An evident drawback in MFCC is that the phase information is lost by taking the magnitude of the Fourier transform. In this paper, we consider a method of utilizing the phase information by treating the magnitudes of real and imaginary components of FFT separately. By applying this method to speech recognition with FVQ/HMM, the speech recognition error rate is found to decrease compared to the conventional MFCC. By numerical analysis, we show also that the optimal value of MFCC components is 12 which come from 6 real and imaginary components of FFT each.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.05a
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• pp.203-207
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• 2006

This paper deals with a problem of detecting BCC using confocal raman spectrum. Specially, we propose Fisher measure based filtering for rejection of frequency components being noisy or non-discriminative. we use PCA (principal component analysis) for reduction of feature space dimension. Also, we apply MAP detector for classification of BCC raman spectrum. The experimental results shows that our proposed method can reduce the feature dimension and also raise the detection ratio.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.9
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• pp.76-90
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• 1999

In this paper, a color image retrieval algorithm is proposed based on color histogram and color texture. The representative color vectors of a color image are made from k-means clustering of its color histogram, and color texture is generated by centering around the color of pixels with its color vector. Thus the color texture means texture properties emphasized by its color histogram, and it is analyzed by Gaussian Markov Random Field (GMRF) model. The proposed algorithm can work efficiently because it does not require any low level image processing such as segmentation or edge detection, so it outperforms the traditional algorithms which use color histogram only or texture properties come from image intensity.

• The Journal of Korean Association of Computer Education
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• v.9 no.2
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• pp.101-109
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• 2006

We propose an adaptive digital watermarking algorithm using HVS(human visual system) and SOM(Self-Organizing Map) among neural networks. This method adjusts adaptively the strength of the watermark which is embedded in different blocks according to block classification in DCT(Discrete Cosine Transform) domain. All blocks in 3 classes out of 4 are selected to embed a watermark. Watermark sequences are embedded in 6 lowest frequency coefficients of each block except the DC component. The experimental results are excellent.

• Geophysics and Geophysical Exploration
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• v.23 no.1
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• pp.50-54
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• 2020

Herein, the closed-form expressions of the magnetic field due to an axially symmetric body such as a right cylinder, are derived. The magnetic field due to a right cylinder is converted from the gravity gradient tensor using Poisson's relation; the magnetic field induced by a constant magnetization can be obtained from the gravity gradient tensor with a constant density. Because of the axial symmetry of the cylinder, the expressions of gravity gradient tensor are derived in cylindrical coordinate and then transformed into Cartesian coordinates for the three components of the magnetic field using an arbitrary magnetization direction.

• The Journal of the Acoustical Society of Korea
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• v.25 no.1
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• pp.14-20
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• 2006

In this paper. a novel technique to set up the initial weights in BSS of delayed mixtures is proposed. After analyzing Eigendecomposition for the correlation matrix of mixing data. the initial weights are set from the Eigenvectors ith delay information. The Proposed setting of initial weighting method for conventional FDICA technique improved the separation Performance. The computer simulation shows that the Proposed method achieves the improved SIR and faster convergence speed of learning curve.

• Journal of the Korean Data and Information Science Society
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• v.25 no.3
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• pp.547-554
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• 2014

This paper discusses a method of estimating variance components for random effects model. Henderson's method I and III are discussed for the esimation of variance components. This paper shows how to use projections instead of using Henderson's methods for the calculation of sums of squares which are quadratic forms in the observations. It also discusses that eigenvalues can be used for getting the expectations of sums of squares in place of using the method of Hartley's synthesis. It shows the suggested method is much more effective than those methods.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.2
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• pp.119-125
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• 2004

The direction component uses mainly the sobel and FFT method. The sobel method is difficult to set representative direction when we wish to extract representative direction when we wish to extract representative direction component and the complicated processing process of sobel mask because same value appears in the low provision image or high provision image and we cannot accumulate tilt size in case of making accumulate after making unit vector to pixel. The method that uses FFT conversion for direction extraction is possible in case that ridge has correct direction specification and must use a special direction filter. After thinning the binary image to supplement above weak point in the paper, we extract direction component by pixel unit, and we extract the most direction components of pixel that exist in block of 8${\times}$8 pixels size as representative direction of ridge.

• Journal of the Korea Society of Computer and Information
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• v.18 no.9
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• pp.131-138
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• 2013

In this paper, I propose and evaluate the method that classifies emotional type of characters with their emotional words. Emotional types are classified as three types such as positive, negative and neutral. They are selected by classification of emotional words that characters speak. I propose the method to extract emotional words based on WordNet, and to represent as emotional vector. WordNet is thesaurus of network structure connected by hypernym, hyponym, synonym, antonym, and so on. Emotion word is extracted by calculating its emotional distance to each emotional category. The number of emotional category is 30. Therefore, emotional vector has 30 levels. When all emotional vectors of some character are accumulated, her/his emotion of a movie can be represented as a emotional vector. Also, thirty emotional categories can be classified as three elements of positive, negative, and neutral. As a result, emotion of some character can be represented by values of three elements. The proposed method was evaluated for 12 characters of four movies. Result of evaluation showed the accuracy of 75%.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.136-136
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• 2019

원형 실린더를 주변 흐름에 관한 연구는 오랜 기간 유체역학 전 영역에서 모형실험이나 수치모형으로 광범위하게 연구되었다. 이 흐름은 하천의 교각이나, 바다의 시추선과 같은 수공구조물 주변에서 관측된다. 난류와 와류가 공존하는 복잡한 특성 때문에, 이 흐름은 수공학에서 유사이송, 세굴, 오염물 확산 등에 영향을 준다. 본 연구는 실험실 수로에 설치된 원형 실린더(D=9cm) 후방의 근접 와류 구간에서(x/D<5) 유속을 ADV로 측정한 후, 난류 특성을 Power Spectral Estimation(PSE)와 Singular Spectral Analysis(SSA) 방법으로 연구하였다. PSE는 샘플 스펙트럼의 한계를 보완하고자 자료를 분할하고, window 함수를 적용하여 ensemble 평균을 구하는 경험적 방법이다. PSE를 이용하여 스펙트럼을 계산한 결과, 주 흐름 및 횡방향 흐름은 Inertial subrange에서 Kolmogorov의 가정과 일치하는 추세를 보였다. 그러나 수심방향 흐름의 스펙트럼은 -5/3보다 빠르게 감소하는 추세를 보였다. Inertial subrange 스펙트럼에서 난류 에너지 소산율은 원형 실린더에서 멀어짐에 따라 감소하는 추세를 보였고, 주 흐름방향과 횡방향 흐름은 비슷한 크기를 보였다. 난류 에너지 소산율과 동점성계수를 이용하여 Kolmogorov 길이, 유속, 시간 스케일을 계산했다. 난류의 운동에너지를 계산하기 위해 Triple decomposition 방법 중 하나인 SSA를 적용하였다. SSA는 유속행렬을 이용하여 고윳값과 고유벡터를 계산하고, 유속에서 기여도가 큰 부분을 추출하는 방법이다. SSA를 통해 실린더 후방 흐름에서 와류 성분과 난류 성분을 나누었다. 횡방향 흐름은 강한 와류로 큰 기여도를 갖는 고유벡터가 나타났지만, 주 흐름과 수심방향 흐름은 상대적으로 낮은 기여도를 갖는 고유벡터가 나타났다. 와류를 제외한 흐름에서 난류 운동에너지는 실린더와 멀어짐에 따라 감소하고, 흐름 중앙에서(y/D=0) 가장 큰 값을 보였다.