• 대한전자공학회논문지SP
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• 제41권3호
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• pp.221-229
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• 2004

The Continuous Wavelets Transform project signal f(t) to "Time-scale"plan utilizing the time varied function which called "wavelets". This Transformation permit to analyze scale time dependence of signal f(t) thus the local or global scale properties can be extracted. Moreover, the signal f(t) can be reconstructed stably by utilizing the Inverse Continuous Wavelets Transform. In this paper, the EEG signal is analyzed by wavelets coherence method and the De-noising procedure is represented.

• Korean Journal of Mathematics
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• 제28권4호
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• pp.649-671
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• 2020

In this paper we give the harmonic analysis associated with the Cherednik operators, next we define and study the Cherednik wavelets and the Cherednik windowed transforms on ℝd, in the W-invariant case, and we prove for these transforms Plancherel and inversion formulas. As application we give these results for the Gaussian Cherednik wavelets and the Gaussian Cherednik windowed transform on ℝd in the W-invariant case.

• Journal of applied mathematics & informatics
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• 제30권3_4호
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• pp.561-570
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• 2012

Fourier transform is well known for trigonometric systems. It is also a very useful tool for the construction of wavelets. The method of constructing wavelets has evolved as times went by. We review some methods. Then we do some calculations on wavelets defined by its Fourier transform.

• 반도체디스플레이기술학회지
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• 제19권4호
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• pp.77-83
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• 2020

The Linear system analysis for physical system is very powerful tool for system diagnostic utilizing relationship between the input signal and output signal. This method utilized generally to investigate physical properties of system and the nondestructive test by ultrasonic signals. This method can be explained by linear system theory. In this paper the Continuous Wavelets Transform is utilized to search the relation between the linear system and continuous wavelets transform.

• IEIE Transactions on Smart Processing and Computing
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• 제5권6호
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• pp.403-417
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• 2016

This paper reviews recent published works dealing with the application of wavelets to image processing based on multiresolution analysis. After revisiting the basics of wavelet transform theory, various applications of wavelets and multiresolution analysis are reviewed, including image denoising, image enhancement, super-resolution, and image compression. In addition, we introduce the concept and theory of quaternion wavelets for the future advancement of wavelet transform and quaternion multiresolution applications.

• 한국전자통신학회논문지
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• 제19권1호
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• pp.113-118
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• 2024

본 논문에서는 음향신호의 배경잡음을 소거하기 위한 시스템에서 최적의 wavelet을 제안한다. 이 시스템은 기존의 단구간 푸리에변환(STFT: Short Time Fourier Transform) 대신 이산 웨이블릿변환(DWT: Discrete Wavelet Transform)을 수행한 후 심층학습과정을 통하여 잡음소거 성능을 개선하였다. DWT는 다해상도 대역통과필터 기능을 하며 각 레벨에서 모 웨이블릿을 시간 이동시키고 크기를 스케일링한 여러 웨이블릿을 이용하여 변환 파라미터를 구한다. 여기서 음성을 분석하는데 가장 적합한 모(mother) 웨이블릿을 선정하기 위해 여러 웨이블릿에 대한 잡음소거 성능을 실험하였다. 본 연구에서 여러 웨이블릿에 대한 잡음소거시스템의 성능을 검증하기 위하여 Tensorflow와 Keras 라이브러리를 사용한 시뮬레이션 프로그램을 작성하고 가장 많이 사용되는 4개의 wavelet에 대해 모의실험을 수행하였다. 실험 결과, Haar 또는 Daubechies 웨이블릿을 사용하는 경우가 가장 우수한 잡음소거 성능을 나타냈으며 타 웨이블릿을 사용하는 경우보다 평균자승오차(MSE: Mean Square Error)가 크게 개선되는 것을 볼 수 있었다.

• Korean Journal of Mathematics
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• 제24권2호
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• pp.235-271
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• 2016

By using the Heckman-Opdam theory on ${\mathbb{R}}^d$ given in [20], we define and study in this paper, the generalized wavelets on ${\mathbb{R}}^d$ and the generalized wavelet transform on ${\mathbb{R}}^d$, and we establish their properties. Next, we prove for the generalized wavelet transform Plancherel and inversion formulas.

• 대한전기학회논문지:전력기술부문A
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• 제49권9호
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• pp.425-432
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• 2000

Wavelet transform is a new method fro electric power quality analysis. Several types of mother wavelets are compared using voltage sag data. Investigations on the use of some mother wavelets, namely Daubechies, Symlets, Coiflets, Biorthogonal, are carried out. On the basis of extensive investigations, optimal mother wavelets for the detection of voltage sag are chosen. The recommended mother wavelet is 'Daubechies 4(db4)' wavelet. 'db4', the most commonly applied mother wavelet in the power quality analysis, can be used most properly in disturbance phenomena which occurs rapidly for a short time. This paper presents a discrete wavelet transform approach for determining the beginning time and end time of voltage sags. The technique is based on utilising the maximum value of d1(at scale 1) coefficients in multiresolution analysis(MRA) based on the discrete wavelet transform. The procedure is fully described, and the results are compared with other methods for determining voltage sag duration, such as the RMS voltage and STFT(Short-Time Fourier Transform) methods. As a result, the voltage sag detection using wavelet transform appears to be a reliable method for detecting and measuring voltage sags in power quality disturbance analysis.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.589-592
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• 1998

One of the main techniques for diagnosing heart disease is by examining the electrocardiogram(ECG). The earlier noise reduction techniques can not effectively cancellation complex noise from the noisy ECG such powrline interference, baseline drift, muscle artifact. In this paper, we performed the extrude noise from and recovering the ECG signal using wavelets transform that has recently been applying to various fields.

• 한국염색가공학회지
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• 제18권5호
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• pp.88-93
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• 2006

A data compression system has been developed by combining adaptive wavelets and optimization technique. The adaptive wavelets were made by optimizing the coefficients of the wavelet matrix. The optimization procedure has been performed by criteria of minimizing the reconstruction error. The resulting adaptive basis outperformed such conventional basis as Daubechies-5 by 5-10%. It was also shown that the yarn density profiles could be compressed by over 95% without a significant loss of information.