• Journal of the Chungcheong Mathematical Society
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• v.30 no.1
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• pp.21-29
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• 2017

We review a partial trace alternatively defined by the composition of positive linear maps, and see how the partial trace acts on the matrix geometric means. We also study the quantum Tsallis relative entropy under partial trace related with the fidelity.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2001.11a
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• pp.121-126
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• 2001

In this paper, for n = 2m and odd prime p, new generalized bent functions from the finite field F$\_$p$^n$/ to the prime field F$\_$p/ are constructed from the partial spreads for F$\_$p$^n$/. Closed form expressions for the proposed generalized bent functions and their trace transform are derived in the form of the trace functions. The trace expressions for the bent functions and their trace transforms defined on F(equation omitted) constructed by using PS- are also derived.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1786-1795
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• 2015

It is common practice to identify the insulation faults of GIS through monitor the contents of SF₆ decomposed components. Partial discharges (PD) could lead to the decomposition of SF₆ dielectric, so new reactions usually occur in the mixture of the newly decomposed components including traces of H₂O and O₂. The new reactions also cause the decomposed components to differ due to the different amounts of H₂O and O₂ even under the same strength of PD. Thus, the accuracy of assessing the insulation faults is definitely influenced when using the concentration and corresponding change of decomposed components. In the present research, a needle-plate electrode was employed to simulate the PD event of a metal protrusion insulation fault for two main characteristic components SO₂F₂ and SOF₂, and to carry out influence analysis of trace H₂O and O₂ on the characteristic components. The research shows that trace H₂O has the capability of catching an F atom, which inhibits low-sulfide SF_x from recombining into high-sulfide SF₆. Thus, the amount of SOF₂ strongly correlates to the amount of trace H₂O, whereas the amount of SO₂F₂ is weakly related to trace H₂O. Furthermore, the dilution effect of trace O₂ on SOF₂ obviously exceeds that of SO₂F₂.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.10
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• pp.515-522
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• 2004

In this study, we tried to investigate that the advantages of SOM(Self Organizing Map) algorithm such as data accumulation ability and the degradation trend trace ability would be adaptable to the analysis of partial discharge pattern recognition. For the purpose, we analyzed partial discharge data obtained from the typical artificial defects in GIS and XLPE power cable system through SOM algorithm. As a result, partial discharge pattern recognition could be well carried out with an acceptable error by use of Kohonen map in SOM algorithm. Also, it was clarified that the additional data could be accumulated during the operation of the algorithm. Especially, we found out that the data accumulation ability of Kohonen map could make it possible to suggest new patterns, which is impossible through the conventional BP(Back Propagation) algorithm. In addition, it is confirmed that the degradation trend could be easily traced in accordance with the degradation process. Therefore, it is expected to improve on-site applicability and to trace real-time degradation trends using SOM algorithm in the partial discharge pattern recognition

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.6A
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• pp.549-554
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• 2002

In this paper, for n=2m and odd prime p, new generalized bent functions from the finite field $F_{p^n}$ to the prime field $F_p$ are constructed from the partial spreads for $F_{p^n}$. Closed form expressions for the proposed generalized bent functions and their trace transform are derived in the form of the trace functions.

• Journal of Communications and Networks
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• v.5 no.1
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• pp.1-6
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• 2003

In this paper, we extend the derivation of the iterative soft-output Viterbi algorithm (SOVA) for partial response (PR) channels, and modify its decoding process such that it works consistently for arbitrary high code rates, e.g., rate 64/65. We show that the modified SOVA always outperforms the conventional SOVA that appears in the literature with a significant difference for high code rates. It also offers a significant cut down in the trace-back computations. We further examine its performance for parallel and serial concatenated codes on a precoded Class IC partial response (PR4) channel. Code rates of the form $\frac{k_0}{k_0+1}$($k_0$ = 4, 8, and 64) are considered. Our simulations indicate that the loss suffered by the modified SOVA, relative to the APP algorithm, is consistent for all code rates and is at most 1.2 dB for parallel concatenations and at most 1.6 dB for serial concatenations at $P_b$ = $10^{-5}$.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.12
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• pp.553-557
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• 2005

This paper describes the application results of an ultrasonic detection system for the power transformer. The ultrasonic detection system with 6 sensors was applied to detect partial discharge in a 154kV transformer with a dangerous levels of $C_{2}H_{2},\;C_{2}H_4$ and $CH_{4}$ gases. The ultrasonic detection tests were carried out 2 times, respectively, to confirm the existence and location of the partial discharge in the transformer. As a result of internal inspection, the arc trace between the pressure ring and core due to the partial discharge was found at the estimated position based on the amplitude and arriving time of the ultrasonic signals. Therefore, it was verified that the ultrasonic detection system is effective as a preventive diagnosis method for the power transformer. Also, the reliability of the ultrasonic detection system in detecting partial discharges in the transformer was also confirmed. It is expected, therefore, that the ultrasonic detection system will have beneficial effects on applications and verifications in detecting partial discharges for the power transformer.

• The Journal of the Petrological Society of Korea
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• v.21 no.2
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• pp.217-233
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• 2012

Major elements abundances of Cretaceous to Tertiary volcanic rocks in Kyongsang basin are similar with Southern Volcanic Zone (SVZ) in Andes. Sr, K, Rb, $Ba{\pm}Th$ abundances, which have low ionic charge, are selectively fertile, on the other hand Ta, Nb, Ce, P, Zr, Hf, Sm, Ti, Y, Yb, Sc, Cr abundances are low. K, Sr, Th show characteristic spikes and Nb show remarkable trough on trace elements spider diagram. Trace elements abundances are higher than that of Andes which is supposed to mantle sources of Kyongsang basin volcanic rocks are produced lower degree of partial melting than SVZ in Andes.

• Proceedings of the KIEE Conference
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• 2004.05b
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• pp.109-112
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• 2004

In this study, the applicability of SOM(Self Organizing Map) algorithm to partial discharge pattern recognition have been investigated. For the purpose, using acquired data from the artificial defects in GIS, SOM algorithm which has some advantages such as data accumulation ability and the degradation trend trace ability was compared with conventionally used BP(Back Propagation) algorithm. As a result, basically BP algorithm was found out to be better than SOM algorithm. Therefore, it is needed to apply SOM algorithm in combination with BP algorithm in order to improve on-site applicability using the advantages of SOM. Also, for the pattern recognition by use of PRPDA(Phase Resolved Partial Discharge Analysis) it is required the normalization of the PRPDA graph. However, in case of the normalization both BP and SOM algorithm have shown worse results, so that it is required further study to solve the problem.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.6
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• pp.36-42
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• 2007

According to the increased demand of high quality multimedia content, it needs to recover an old movies. But the film of old movie is damaged with line scratches and dust. In this paper, the detection and restoration algorithm of B/W line scratch is proposed. Our scheme estimates and interpolates the damaged partial information of line scratch using the linear recursive curve trace which consider the intensity values of left and right region of line scratch and then median filtering processed. As a result, the film image PSNR 44.68 with B/W line scratch is increased up to 48.60 and the intensity of the interpolate pixel is approached about 14 against the pixel of original image.