• Journal of Broadcast Engineering
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• v.5 no.1
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• pp.31-40
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• 2000

In this paper, we propose an edge histogram to efficiently represent the edge distribution in the image for MPEG-7. To this end, we adopt global, semi-global, and local edge histogram bins. Also, we extract the edge information from the image in terms of image blocks rather than pixels, which reduces the extraction complexity and is also applicable to the block-based compression standards such as MPEG-1, and 2. Experimental results show that the proposed method yields better retrieval accuracy and feature extraction speed comparing to other non-homogeneous texture descriptors of MPEG-7 including the wavelet-based descriptor and local edge-based descriptor.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1A
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• pp.89-97
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• 2002

This paper proposes the adaptive digital watermarking method for the ownership protection of images. The watermarks are inserted to a selected area rather than a whole area. The proposed method reduces the distortion caused by the watermarking process. To select the regions, roughness of the image should be considered because the watermarks in the smooth regions are easily detected through the human eyes. To find the rough regions, Discrete Cosine Transform (DCT) method is used. Generally, the high frequency regions of images are lost by the compression process such as JPEG. So, the watermarks are inserted to the low frequency regions of a selected area by using the proposed method. The proposed method reduce the image loss or distortion brought by the image processing, such as compression, filtering, scaling, addition of noise, cropping, and wavelet transform.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.4 s.304
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• pp.39-48
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• 2005

This paper proposes novel texture segmentation method using Bayesian estimation method and neural networks. We use multi-scale wavelet coefficients and the context information of neighboring wavelets coefficients as the input of networks. The output of neural networks is modeled as a posterior probability. The context information is obtained by HMT(Hidden Markov Tree) model. This proposed segmentation method shows better performance than ML(Maximum Likelihood) segmentation using HMT model. And post-processed texture segmentation results as using multi-scale Bayesian image segmentation technique called HMTseg in each segmentation by HMT and the proposed method also show that the proposed method is superior to the method using HMT.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9B
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• pp.1570-1578
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• 2000

A quadrature pair of filter banks that are composed of a pair of cosine and sine modulated filter banks is applied to MC-CDMA data transmultiplexing in the view point of mitigating inter-channel interferences. Exploiting superior capabilities of wavelet properties in composing the filter banks the proposed scheme is capable of compromising inter-channel interference problems better than the conventional DFT-based MC-CDMA due to superior subchannelization effects. To verify the behavior of our proposed MC-CDMA system based on the quadrature filter banks the reverse-link bit error rates with respect to signal-to-noise ratio under Rayleigth fading and additive white Gaussian noise channel environments are computed. The results show an improved system performance over the conventional MC-CDMA in the view point of minimizing interference effects.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1C
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• pp.48-55
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• 2009

In scalable video coding, MCTF plays an important role for time-scalability and SNR-scalability. But there is image quality decreasing as MCTF level is increased because time interval of each frame is extended so that is hard to find suitable motion vector. In this paper, we propose an algorithm to prevent image quality from decreasing with unsuitable motion vector during MCTF update process using JND. We adapt JND to find errors within blocks of image and set a threshold which is used to add high frequency components during update process. We can overcome time-gap between frames and achieve better image quality through the proposed algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.1
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• pp.11-17
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• 1998

One of the main techniques for diagnosing heart disease is by examining the electrocardiogram(ECG). Many studies on detecting the QRS complex, p, and T waves have been performed because meaningful information is contained in these parameters. However, the earlier detecting techniques can not effectively extract those parameters from the ECG that is severely contaminated by noise source. In this paper, we performed the extracting parameters from and recovering the ECG signal using wavelets transform that has recently been applying to various fields.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.6B
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• pp.1002-1011
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• 2000

In this paper, we propose a multiresolution progressive image transmission with spatial and bit-rate scalabilities using a $2{\times}2$ DCT. The multiresolition image represented by a $2{\times}2$ DCT is used for the progressive image transmission with spatial and bit-rate scalabilities. Because the proposed progressive image transmission method supports both spatial and bit-rate scalabilities, it can be adaptively applied to the receiver's scalability requests. We compare the proposed progressive transmission with that of the higher-order convolution-based Wavelet method. Comparisons show that the proposed method needs much less computations, but insignificant loss of image quality.

• Journal of Internet Computing and Services
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• v.4 no.4
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• pp.27-34
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• 2003

Digital image manipulation software is now readily available on personal computers. It is therefore very simple to tamper with any image and make it available to others. Therefore. copyright protection of digital contents and insurance of digital image integrity become major issues. In this paper, we propose a hybrid watermarking method to identify locations of tampered region as well as copyright. Our proposed algorithms embed the PN-sequence into low frequency sub-band of the wavelet transform domain and it doesn't need the original image in extraction procedure. The experimental results show good robustness against any signal processing with tamper detection on still image.

• The Journal of the Acoustical Society of Korea
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• v.38 no.3
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• pp.363-369
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• 2019

Various studies have been conducted for the diagnosis of noise condition of complex rotary machines. In this study, diagnosis index using vibration signal is developed for the efficient and objective assessment of noise condition of a blower motor. The noise most commonly caused by the abnormal blower motor are Tick/Click noise and Tone noise. According to cause and noise characteristics, time-frequency analysis is used to diagnose Tick/Click noise, and smoothing in frequency domain is used to diagnose tone noise condition. The noise condition of the blower motors were diagnosed using the developed index and these results are compared with the diagnostic results by the experts. As a result, the agreement rate was about 95 %.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.172-172
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• 2021

주된 물관리 시설의 신뢰성 있는 운영 계획의 수립을 위하여 충분한 길이의 유입량을 확보하는 것은 중요하나 현실적으로 제한된 관측 자료만 존재한다. 본 연구에서는 충분한 길이의 유입량을 생성하기 위하여 유입량의 모의 방법론을 제안하고자 한다. 제안하는 모형은 크게 3가지의 방법론을 기반으로 한다. 첫 번째는 연 유입량과 월 유입량의 생성단계로 Wavelet 기반으로 Autoregressive-moving-average(ARMA)을 적용할 것이다. 다음으로 일 유입량의 생성에 있어서 과거 관측값을 기반으로 한 Z-Score-based jittering 방법론을 적용할 것이다. 이렇게 각각 생성된 연 유입량, 월 유입량 그리고 일 유입량을 K-Nearest Nedighbors (K-NN) 방법론을 이용하여 최종 유입량을 결정하고자 한다. 생성된 유입량의 유용성을 판단하기 위하여 본 연구에서는 단기와 장기에서의 시계열의 지속성을 허스트 지수와 상관계수를 사용하여 검증할 것이며 이를 과거 관측치와 비교하고자 한다. 또한 각각의 연, 월, 일별의 기준으로 주요 통계치인 평균과 표준편차를 과거 관측 시계열의 통계치와 비교하여 그 유용성을 판단할 것이다.