• Journal of Electrical Engineering and Technology
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• v.11 no.3
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• pp.560-574
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• 2016

This paper presents a novel method for power system harmonic estimation based on the Park transform. The proposed method firstly extends the signal to a group of three-phase signals in a-b-c coordinate. Then, a linear fitting based method is adopted to estimate the fundamental frequency. Afterwards, the Park transform is utilized to convert the three-phase signals from a-b-c coordinate to d-q-0 coordinate. Finally, the amplitude and phase of a harmonic component of interest can be calculated using the d-axis and q-axis components obtained. Simulation studies have been conducted using matrix laboratory (MATLAB) and power system computer aided design/electromagnetic transients including direct current (PSCAD/EMTDC). Simulation studies in MATLAB have considered three scenarios, i.e., no-frequency-deviation scenario, frequency-deviation scenario and the scenario in the presence of inter-harminics. The results have demonstrated that the proposed method achieves very high accuracy in frequency, phase and amplitude estimation under noisy conditions, and suffers little influence of the inter-harmonics. Moreover, comparison studies have proved that the proposed method is superior to FFT and Interpolated FFT with the Hanning Window (IpFFTHW). Finally, a popular case in PSCAD/EMTDC has been employed to further verify the effectiveness of the proposed method.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.718-720
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• 2005

반짝이는 물체를 촬영하면 이미지에 하이라이트(highlight)와 반짝거림(specularity)이 발생한다. 하이라이트가 발생한 이미지에서 하이라이트를 제거하고 원색으로 복원하는 방법 중에 하나가 하이라이트 색 복원(inpainting)이다. 하이라이트 색을 복원하는 과정은 다음 두 단계로 구성된다. 첫 단계로 하이라이트의 위치를 알고 있다고 가정하aus 하이라이트의 주변 영역을 찾고 CL-projection을 이용해 주변 영역의 색에서 하이라이트나 반짝거림의 영향을 제거한다. 두 번째 단계로 하이라이트 주변 영역의 색을 기반으로 upper mean을 이용하여 distance transform을 수행한다. Upper mean을 이용한 distance transform의 가장 큰 장점은 하이라이트 주변을 보정하고 그 정보를 이용하기 때문에 하이라이트 색을 복원할 뿐만 아니라 반짝거림에 대한 보정도 된다.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.12
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• pp.1527-1536
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• 1999

In this paper, a triply-encoded Hadamard transform imaging spectrometer is proposed by applying the grill spectrometer to the Hadamard transform imaging spectrometer. The proposed system encodes the input radiation triply ; once through the input image mask and twice through the two masks in the grill spectrometer. We use an electro-optical mask in the grill spectrometer which is controlled by a left-cyclic simplex matrix. Then we modeled the system using $D^{-1}$ method. In this paper, the average mean square error associated with a recovered estimate is considered for performance evaluation. The relative performance is compared with those of the other conventional systems.

• JSTS:Journal of Semiconductor Technology and Science
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• v.12 no.2
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• pp.203-211
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• 2012

This paper proposes a $16{\times}16$ and $32{\times}32$ inverse transform architecture for HEVC (High Efficiency Video Coding). HEVC large transform of $16{\times}16$ and $32{\times}32$ suffers from huge computational complexity. To resolve this problem, we proposed a new large inverse transform architecture based on hardware reuse. The processing element is optimized by exploiting fully recursive and regular butterfly structure. To achieve low area, the processing element is implemented by shifters and adders without multiplier. Implementation of the proposed 2-D inverse transform architecture in 0.18 ${\mu}m$ technology shows about 300 MHz frequency and 287 Kgates area, which can process 4K ($3840{\times}2160$)@ 30 fps image.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.165-168
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• 2000

A fast estimation method using wavelet transform for a time delay system is proposed. Main point of this method is to get the wavelet transform of the correlation between the input signal and delayed signal using transformed signals. But wavelet transform using Haar wavelet functions has basis with different phases and can offers a bisection method to estimate a time delay of a signal. Selective computation of the transform of correlation is performed and the computational complexity is reduced. Computational order of this method is O(N log N) and it is much love. than a simple correlation esimation when the length of signal is long.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.617-622
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• 2002

This paper presents that the Wavelet Transform can be used to detect the various local defects in a gearbos. Two types of defects which are broken tooth and localized wear, are experimented and the signals are collected by accerometer and analyzed. Because of the complecity of the signals acquired from sensor, it is needed to identify the interesting signal. The natural frequencies of shafts and the gear mesh frequency(GMF) is calculated theretically. DWT, CWT and the aplication are used to extract a gear-localized defect feature from the vibration signal of the gearbox with the defective gear. The results shows the transform is more effective to detect the failures than the Fourier Transform.

• Communications for Statistical Applications and Methods
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• v.22 no.2
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• pp.159-172
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• 2015

This paper considers the problem of reconstructing an underlying signal from noisy data. This paper presents a reconstruction method based on synchrosqueezed wavelet transform recently developed for multiscale representation. Synchrosqueezed wavelet transform based on continuous wavelet transform is efficient to estimate the instantaneous frequency of each component that consist of a signal and to reconstruct components. However, an objective selection method for the optimal number of intrinsic mode type functions is required. The proposed method is obtained by coupling the synchrosqueezed wavelet transform with cross-validation scheme. Simulation studies and musical instrument sounds are used to compare the empirical performance of the proposed method with existing methods.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2620-2623
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• 2000

The standard approach consists of using correlation of orthogonal functions in digital filtering, such as well-known FFT(Fast Fourier Transform) and FWT(Fast Walsh Transform). But it needs much calculations, multiplications and additions. The calculation amount is m $log_2m$ in the general case. Therefore, this requires high speed processors to calculate in real time, which can calculate floating point. This study developed improved fast Walsh transform based on dyadic-ordered fast Walsh transform, then regenerated signal flow graph of improved fast Walsh transform, and used it for digital filtering, and then measured fundamental frequency and harmonics for current and voltage signals of power system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.2
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• pp.406-412
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• 2006

In this paper, we propose OHT(optimized nough Transform) algorithm for the lane extraction. Input image is changed into 256 gray revel image. Gray level image is separated into background region and road region by using limited horizontal projection value. In separated road area, we apply OHT algorithm. OHT algorithm is characterized as follows. First, the number of candidate pixels is reduced using the outline orientation of the lane. Second, each range of the left and right lane is defined by limited ${\theta}$ Experimental results show that the proposed method is better than Hough Transform.

• Journal of the Institute of Convergence Signal Processing
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• v.9 no.4
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• pp.295-303
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• 2008

In general, transform domain adaptive filters show faster convergence speed than the time domain adaptive filters, but the amount of calculation increases dramatically as the filter order increases. This problem can be solved by making use of the subband structure in transform domain adaptive filters. In this paper, to increase the convergence speed on the generalized subband decomposition FIR adaptive filters, a structure of the adaptive filter with subfilter of dyadic sparsity factor in wavelet transform domain is designed. And, in this adaptive filter, the equivalent input in transform domain is derived and, by using the input, the convergence properties for the LMS algorithm is analyzed and evaluated. By using this sub band adaptive filter, the inverse system modeling and the periodic noise canceller were designed, and, by computer simulation, the convergence speeds of the systems on LMS algorithm were compared with that of the subband adaptive filter using DFT(discrete Fourier transform).