The Experts below are selected from a list of 147 Experts worldwide ranked by ideXlab platform
Sang-hee Kang - One of the best experts on this subject based on the ideXlab platform.
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Fourier transform-based modified phasor estimation method immune to the effect of the DC offsets
2009 IEEE Power & Energy Society General Meeting, 2009Co-Authors: Sang-hee Kang, P A Crossley, Yong Cheol KangAbstract:Summary form only given. This paper proposes a Fourier transform-based modified phasor estimation method to eliminate the adverse influence of the exponentially decaying DC offsets when discrete Fourier transform (DFT) is used to calculate the phasor of the fundamental frequency component in a relaying signal. By subtracting the result of Odd-Sample-set DFT from the result of even-Sample-set DFT, the information of DC offsets can be obtained. Two DC offsets in a secondary relaying signal are treated as one DC offset which is piecewise approximated in one cycle data window. The effect of the DC offsets can be eliminated by the approximated DC offset. The performance of the proposed algorithm is evaluated by using computer-simulated signals and EMTP-generated signals. The algorithm is also tested on a hardware board with TMS320C32 microprocessor. The evaluation results indicate that the proposed algorithm can estimate the accurate phasor of the fundamental frequency component regardless of not only the primary decaying DC offset but also the secondary decaying DC offset caused by CT circuit itself including its burden.
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fourier transform based modified phasor estimation method immune to the effect of the dc offsets
Power and Energy Society General Meeting, 2009Co-Authors: Sang-hee Kang, P A Crossley, Yong Cheol KangAbstract:This paper proposes a Fourier transform-based modified phasor estimation method to eliminate the adverse influence of the exponentially decaying dc offsets when Discrete Fourier Transform (DFT) is used to calculate the phasor of the fundamental frequency component in a relaying signal. By subtracting the result of Odd-Sample-set DFT from the result of even-Sample-set DFT, the information of dc offsets can be obtained. Two dc offsets in a secondary relaying signal are treated as one dc offset which is piecewise approximated in one cycle data window. The effect of the dc offsets can be eliminated by the approximated dc offset. The performance of the proposed algorithm is evaluated by using computer-simulated signals and EMTP-generated signals. The algorithm is also tested on a hardware board with TMS320C32 microprocessor. The evaluation results indicate that the proposed algorithm can estimate the accurate phasor of the fundamental frequency component regardless of not only the primary decaying dc offset but also the secondary decaying dc offset caused by CT circuit itself including its burden.
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fourier transform based modified phasor estimation method immune to the effect of the dc offsets
IEEE Transactions on Power Delivery, 2009Co-Authors: Sang-hee Kang, P A Crossley, Yong Cheol KangAbstract:This paper proposes a Fourier transform-based modified phasor estimation method to eliminate the adverse influence of the exponentially decaying dc offsets when discrete Fourier transform (DFT) is used to calculate the phasor of the fundamental frequency component in a relaying signal. By subtracting the result of Odd-Sample-set DFT from the result of even-Sample-set DFT, the information of dc offsets can be obtained. Two dc offsets in a secondary relaying signal are treated as one dc offset which is piecewise approximated in one cycle data window. The effect of the dc offsets can be eliminated by the approximated dc offset. The performance of the proposed algorithm is evaluated by using computer-simulated signals and Electromagnetic Transients Program-generated signals. The algorithm is also tested on a hardware board with TMS320C32 microprocessor. The evaluation results indicate that the proposed algorithm can estimate the accurate phasor of the fundamental frequency component regardless of not only the primary decaying dc offset but also the secondary decaying dc offset caused by CT circuit itself including its burden.
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Distance relaying algorithm using a DFT-based modified phasor estimation method
2009 IEEE Bucharest PowerTech, 2009Co-Authors: Ye-jim Oh, Sang-hee KangAbstract:In this paper, we propose a distance relaying algorithm using a discrete Fourier transform (DFT)-based modified phasor estimation method to eliminate the adverse influence of exponentially decaying DC offsets. Most distance relays are based on estimating phasors of the voltage and current signals. A DFT is generally used to calculate the phasor of the fundamental frequency component in digital protective relays. However, the output of the DFT contains an error due to exponentially decaying DC offsets. For this reason, distance relays have a tendency to over-reach or under-reach in the presence of DC offset components in a fault current. Therefore, the decaying DC components should be taken into consideration when calculating the phasor of the fundamental frequency component of a relaying signal. The error due to DC offsets in a DFT is calculated and eliminated using the outputs of an even-Sample-set DFT and an Odd-Sample-set DFT, so that the phasor of the fundamental component can be accurately estimated. The performance of the proposed algorithm is evaluated for a-phase to ground faults on a 345 kV, 50 km, simple overhead transmission line. The Electromagnetic Transient Program (EMTP) is used to generate fault signals. The evaluation results indicate that adopting the proposed algorithm in distance relays can effectively suppress the adverse influence of DC offsets.
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New modified fourier algorithm to eliminate the effect of the DC offset on phasor estimation using DFT
2008 IEEE PES Transmission and Distribution Conference and Exposition, 2008Co-Authors: Sang-hee KangAbstract:This paper proposes a new modified Fourier algorithm to eliminate the adverse influence of a decaying dc offset when Discrete Fourier transform (DFT) is used to estimate the phasor of the fundamental frequency component. The proposed algorithm decomposes the DFT process into even Sample set DFT and Odd Sample set DFT. The effect of the dc offset is eliminated by using the recursive relationship between the outputs of even Sample set DFT and Odd Sample set DFT. The performance of the algorithm is evaluated by using computer- simulated signals and EMTP-generated signals. The evaluation results indicate that the proposed algorithm can estimate the accurate phasor of the fundamental frequency component regardless of not only the primary decaying dc offset but also the secondary decaying dc offset caused by CT circuit itself including its burden.
Yong Cheol Kang - One of the best experts on this subject based on the ideXlab platform.
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Fourier transform-based modified phasor estimation method immune to the effect of the DC offsets
2009 IEEE Power & Energy Society General Meeting, 2009Co-Authors: Sang-hee Kang, P A Crossley, Yong Cheol KangAbstract:Summary form only given. This paper proposes a Fourier transform-based modified phasor estimation method to eliminate the adverse influence of the exponentially decaying DC offsets when discrete Fourier transform (DFT) is used to calculate the phasor of the fundamental frequency component in a relaying signal. By subtracting the result of Odd-Sample-set DFT from the result of even-Sample-set DFT, the information of DC offsets can be obtained. Two DC offsets in a secondary relaying signal are treated as one DC offset which is piecewise approximated in one cycle data window. The effect of the DC offsets can be eliminated by the approximated DC offset. The performance of the proposed algorithm is evaluated by using computer-simulated signals and EMTP-generated signals. The algorithm is also tested on a hardware board with TMS320C32 microprocessor. The evaluation results indicate that the proposed algorithm can estimate the accurate phasor of the fundamental frequency component regardless of not only the primary decaying DC offset but also the secondary decaying DC offset caused by CT circuit itself including its burden.
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fourier transform based modified phasor estimation method immune to the effect of the dc offsets
Power and Energy Society General Meeting, 2009Co-Authors: Sang-hee Kang, P A Crossley, Yong Cheol KangAbstract:This paper proposes a Fourier transform-based modified phasor estimation method to eliminate the adverse influence of the exponentially decaying dc offsets when Discrete Fourier Transform (DFT) is used to calculate the phasor of the fundamental frequency component in a relaying signal. By subtracting the result of Odd-Sample-set DFT from the result of even-Sample-set DFT, the information of dc offsets can be obtained. Two dc offsets in a secondary relaying signal are treated as one dc offset which is piecewise approximated in one cycle data window. The effect of the dc offsets can be eliminated by the approximated dc offset. The performance of the proposed algorithm is evaluated by using computer-simulated signals and EMTP-generated signals. The algorithm is also tested on a hardware board with TMS320C32 microprocessor. The evaluation results indicate that the proposed algorithm can estimate the accurate phasor of the fundamental frequency component regardless of not only the primary decaying dc offset but also the secondary decaying dc offset caused by CT circuit itself including its burden.
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fourier transform based modified phasor estimation method immune to the effect of the dc offsets
IEEE Transactions on Power Delivery, 2009Co-Authors: Sang-hee Kang, P A Crossley, Yong Cheol KangAbstract:This paper proposes a Fourier transform-based modified phasor estimation method to eliminate the adverse influence of the exponentially decaying dc offsets when discrete Fourier transform (DFT) is used to calculate the phasor of the fundamental frequency component in a relaying signal. By subtracting the result of Odd-Sample-set DFT from the result of even-Sample-set DFT, the information of dc offsets can be obtained. Two dc offsets in a secondary relaying signal are treated as one dc offset which is piecewise approximated in one cycle data window. The effect of the dc offsets can be eliminated by the approximated dc offset. The performance of the proposed algorithm is evaluated by using computer-simulated signals and Electromagnetic Transients Program-generated signals. The algorithm is also tested on a hardware board with TMS320C32 microprocessor. The evaluation results indicate that the proposed algorithm can estimate the accurate phasor of the fundamental frequency component regardless of not only the primary decaying dc offset but also the secondary decaying dc offset caused by CT circuit itself including its burden.
N Balakrishnan - One of the best experts on this subject based on the ideXlab platform.
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on simultaneous closeness probabilities of order statistics from Odd Sample sizes to the population median
Statistical Methodology, 2011Co-Authors: N Balakrishnan, Jerome P KeatingAbstract:Abstract In this note, we present alternative derivations for the probability that an individual order statistic is closest to the target parameter among all order statistics from a complete random Sample. This approach is simpler than the geometric arguments used earlier. We also provide a simple direct proof for the symmetry property of the simultaneous closeness probabilities among order statistics for the estimation of percentiles from a symmetric family. Finally, we offer an alternative simpler proof for the result that Sample medians from larger Odd Sample sizes are Pitman closer to the population median than Sample medians from smaller Odd Sample sizes.
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an Odd property of Sample median from Odd Sample sizes
Statistical Methodology, 2010Co-Authors: George Iliopoulos, N BalakrishnanAbstract:Abstract In this paper, we establish some Pitman closeness results concerning the Sample median from a symmetric continuous distribution. We show that when an Odd Sample size is increased by one, the Sample median becomes Pitman-closer to the population median, while when an even Sample size is increased by one, the Sample median need not be Pitman-closer. We establish the former through probabilistic derivations while the latter is through a counterexample. We also discuss the situation when the Sample is increased by two observations.
Jiyoung Yoon - One of the best experts on this subject based on the ideXlab platform.
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confirmation of Odd Sample bias in triadic design preference tests with a no preference option using confusable stimuli and a solution
Food Quality and Preference, 2020Co-Authors: Jiyoung YoonAbstract:Abstract Two preference test methods utilizing triadic designs (i.e., presenting two identical products and a different product in a test) have been proposed to improve the validity of the paired preference test using a no-preference response option, by considering responses generated from preference bias (i.e., consumers’ responses are tilted toward a preference response rather than a no-preference response, resulting in the overestimation of preference responses). One of the test methods was the replicated duo-trio difference-preference (DT-Preference) test method, which had a balanced-reference design, while the other was the triadic preference test method. These two methods were designed to provide more conservative preference results in different ways. For the DT-Preference test method, it was assumed that the preference responses that were simply generated from the preference bias would also be prone to an Odd Sample bias (i.e., consumers tilted the preference against the stimulus that was most different from the other two) in the triadic design. For the triadic preference test method, the responses were screened out if the subjects reported a preference between the identical stimuli, assuming no bias in the triadic design. In the present study, the Odd Sample bias assumed in the triadic design was tested by the triadic preference test method and the DT-Preference test method by using two pairs of confusable orange juice stimuli assumed to have negligible preference by 256 consumers. For the DT-Preference test method, two variants of the duo-trio test designs were used. The Odd Sample bias was confirmed for all test methods using triadic designs, invalidating the application of the triadic preference test method without replication.
S. Dhanjal - One of the best experts on this subject based on the ideXlab platform.
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Artificial neural networks in speech processing: problems and challenges
2001 IEEE Pacific Rim Conference on Communications Computers and Signal Processing (IEEE Cat. No.01CH37233), 2001Co-Authors: S. DhanjalAbstract:The author previously (1993, 1996, 1997) designed several new speech processing techniques, including an efficient analysis/synthesis technique named Odd Sample linear prediction (OSLP), and a speech enhancement (noise cancellation) technique, delayed linear prediction noise cancellation (DLPNC). Traditional digital speech processing approaches have been used while designing these techniques. I conducted a preliminary survey in the field of artificial neural nets (ANN) in speech processing, so that I could apply ANN to these techniques to further improve their performance. While conducting the survey, I realized that the research profile in the area of artificial neural networks is not as mature as in the area of speech processing. Consequently, the research field under consideration (ANN in speech processing) is a relatively young field. This paper summarizes the results of my survey, with special reference to the problems, associated challenges, and limitations I encountered.
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OSLP: a new technique in linear prediction of speech
1997 IEEE Pacific Rim Conference on Communications Computers and Signal Processing PACRIM. 10 Years Networking the Pacific Rim 1987-1997, 1997Co-Authors: S. DhanjalAbstract:Odd Sample linear prediction (OSLP) is a relatively new and efficient technique for analysis/synthesis of speech signals. OSLP is based on the classical theory of linear prediction. The performance of OSLP was further improved by the author. Pitch detection constitutes an important component of this technique. In the work reported so far, the SIFT algorithm, due to Markel and Grey (1976), was used for pitch detection mainly because the SIFT is also based on the classical theory of linear prediction. However, many, virtually dozens of, pitch detection algorithms have been reported in literature. In the work reported in this paper, pitch detection algorithms, other than the SIFT, were employed to investigate if the overall performance of OSLP can be further improved.
