• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.1
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• pp.1-5
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• 2020

In this study, the objective is to improve the criteria used for statistical comparison of the VLF tanδ (TD) database and failure rate according to water-tree degradation in underground distribution power cables. The aging condition of the KEPCO criteria is divided into 6 levels using the Weibull distribution, and the "failure imminent" condition is quantified by using the statistical end-point of the lifetime parameter of the VLF big-data group obtained from KEPCO. Moreover, new criteria with a 2-dimensional combination of TD, DTD, and a statistical normalized factor are suggested. These criteria exhibit high reproducibility for the detection of cables in an imminent failure state. Consequently, it is expected that the adoption of the extended VLF-2019 criteria will reduce the asset management cost of cable replacement compared to the VLF-2012 criteria of KEPCO.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.9
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• pp.1238-1243
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• 2008

Domestic buffalo and cattle are two extremely important livestock species in worldwide agricultural production. In this paper, to investigate genetic diversity and divergence among swamp buffalo, river buffalo and cattle, 30 microsatellite markers were screened on 168 individuals sampled from five populations. Substantial differences were observed among the three groups of animals with respect to allele frequency distribution, allele size and polymorphism. The cattle sample (Mongolian) showed significantly higher genetic variability (0.674 of gene diversity, p<0.01), and the swamp and river buffalo samples displayed similar degree of genetic variation (0.536 in swamp and 0.546 in river, p = 0.92). Results of both phylogenetic tree and multivariate analysis could distinguish three groups of animals, suggesting their deep evolutionary divergence. Additionally, using $({\delta}{\mu})^2$ genetic distance, we estimated a divergence time of 1.7 million years between swamp and river buffalo that strongly supported distinct genetic origins for the two buffalo types.

• Journal of the Korea Furniture Society
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• v.22 no.3
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• pp.199-207
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• 2011

Examined the color of ten species of Korean broadleaf trees were experimented based on $L^*a^*b^*$ values and color difference (${\Delta}E^*ab$) between sapwood and heartwood, in order to analyze and determine the color, a critical visual and decorative factor of the broadleaf trees that can be used for making woodcraft and furniture. According to the result, the entire sapwood and heartwood, except the heartwood of Populus tomentiglandulosa, showed positive value in whiteness, redness, and yellowness and therefore contained yellow and red. None of the species showed color difference between sapwood and heartwood that was trace (0~0.5), slight (0.6~1.5), or very much; whereas Populus maximowiczii showed noticeable color difference (1.5~3.0); Salix koreensis, Betula platyphylla var japonica, Carpinus laxiflora, and Castanea crenata, appreciable and Populus tomentiglandulosa, Juglans mandshurica, Betula schmidtii, Alnus japonica, and Quercus variabilis, much. The color characteristics of heartwood and sapwood of the ten Korean broadleaf tree species studied in this research can be used as basic data for woodcraft or furniture production, especially when replacing foreign woods with Korean ones, and also contribute to convergence researches for science, engineering, and design fields.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.5
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• pp.1825-1839
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• 2015

The final draft of the latest video coding standard, High Efficiency Video Coding (HEVC), was approved in January 2013. The coding efficiency of HEVC surpasses its predecessor, H.264/MPEG-4 Advanced Video Coding (AVC), by using only half of the bitrate to encode the same sequence with similar quality. However, the complexity of HEVC is sharply increased compared to H.264/AVC. In this paper, a method is proposed to decrease the complexity of intra coding in HEVC. Early pruning and an early splitting strategy are applied to the quadtree structure of coding tree units (CTU) and residual quadtree (RQT). According to our experiment, when our method is applied to sequences from Class A to Class E, the coding time is decreased by 44% at the cost of a 1.08% Bjontegaard delta rate (BD-rate) increase on average.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.33-36
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• 2001

Torque ripple control of brush less DC motor has been the main issue of the servo drive systems in which the speed fluctuation, vibration and acoustic noise should be minimized. Most methods for suppressing the torque ripples require Fourier series analysis and either the iterative or least mean square minimization. In this paper, the novel approach to achieve the ripple-tree torque control with maximum efficiency based on the d-q-0 reference frame is presented. The proposed method optimize the reference phase current waveforms including even the case of 3 phase unbalanced condition, and the motor winding currents are controlled to follow up the optimized current waveforms by delta modulation technique. As a result, the proposed approach provides a simple and clear way to obtain the optimal motor excitation currents. The validity and practical applications of the proposed control scheme are verified through the simulations and experimental results.

• ETRI Journal
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• v.38 no.1
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• pp.185-194
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• 2016

In this paper, a novel rate control scheme for low delay video coding of High Efficiency Video Coding (HEVC) is proposed. The proposed scheme is developed by considering a new temporal prediction structure of HEVC. In the proposed scheme, the relationship between bit rate and quantization step is exploited firstly to formulate an accurate quadratic rate-quantization (R-Q) model. Secondly, a method of determining the quantization parameters (QPs) for the first frames within a group of pictures is proposed. Thirdly, an accurate frame-level bit allocation method is proposed for HEVC. Finally, based on the proposed R-Q model and the target bit allocated for the frame, the QPs are predicted for coding tree units by using rate-distortion (R-D) optimization. We compare our scheme against that of three other state-of-the-art rate control schemes. Experimental results show that the proposed rate control scheme can increase the Bjøntegaard delta peak signal-to-noise ratio by 0.65 dB and 0.09 dB on average compared with the JCTVC-I0094 and JCTVC-M0036 schemes, respectively, both of which have been implemented in an HEVC test model encoder; furthermore, the proposed scheme achieves a similar R-D performance to Wang's scheme, as well as obtaining the smallest bit rate mismatch error of all the schemes.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.341-344
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• 2003

This paper proposes a tree-winding transformer protective relaying algorithm based on the ratio of increment of flux linkages (RIFL). The RIFL of the two windings is equal to the turns ratio for all operating conditions except an internal faults. For a single-phase transformer and three-phase transformer containing the wye-connected windings, the increments of flux linkages are calculated. for a three-phase transformer containing the delta-connected windings, the difference of the increments of flux linkages between the two phases are calculated using the line currents, because the winding currents are practically unavailable. Their ratios are compared with the turns ratio. The results of various tests show that the algorithm successfully discriminates internal faults from normal operation conditions such as magnetic inrush, overexcitation and external faults. The algorithm can not only detect internal winding faults, but reduce the operating time of a relay.

• Journal of Life Science
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• v.18 no.11
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• pp.1592-1599
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• 2008

The $\beta$-lactamase gene was cloned into E. coli DH5$\alpha$ from Bacillus sp. J105 with strong resistance against $\beta$-lactam antibiotics. The chromosomal DNA was partially digested with Sau3AI and ligated to BamHI digested pLAFR3. $\beta$-Lactamase positive clones were obtained by using in vitro packaging kit. The pKL11-${\Delta}4.6$ with $\beta$-lactamase activity was obtained by subcloning of the recombinant plasmid ($\beta$-lac +). The 6.5 kb fragment in the subcloned plasmid was sequenced. The DNA fragment that contains the $\beta$-lactamase gene encodes 309 amino acids. The 0.17 kb upstream region was similar to those of B. thuringinesis and B. cereus with 97% identity. The deduced amino acids sequence was also similar to those of $\beta$-lactamase from B. thuringinesis and B. cereus with 97% and 94% identity, respectively. The phylogenetic tree also showed the relationships of the $\beta$-lactamase gene of Bacillus sp. J105 to genetically related that of other Bacillus strains. Analysis of expression pattern of the pKL11-${\Delta}4.6$ in E. coli, revealed that the secretion efficiency of $\beta$-lactamase was $4{\sim}5%$ and the molecular weight was as same as that of original $\beta$-lactamase (31 kDa) from Bacillus sp. J105.

• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.622-628
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• 2017

In order to develop value-added utilization technology of domestic oaks the processing yield rate from the standing tree to the flooring material for the Quercus variabilis and Quercus mongolica were investigated. Also, to reduce drying time, improved drying schedule was applied and the physical properties were measured. The drying time was 173 hours in total, and the final moisture content was 5.39% (Quercus variabilis) and 4.17% (Quercus mongolica). The color difference of oak lumber before and after drying showed a significant change as ${\Delta}E$ value from 7 to 11. The shrinkage rates of Quercus variabilis and Quercus mongolica during drying were 8.1% and 8.5% in the tangential direction and 5.0% and 6.2% in the radial direction, respectively. The lumber manufacturing yield rate of sawn lumber was 30 to 40% and that of the final product was 8 to 15%. It is expected that the processing characteristics of the Quercus species investigated in this research could contribute to formulate an efficient production plan of domestic hardwoods that are still under utilization.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.12
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• pp.141-146
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• 2016

HEVC/H.265 is the latest joint video coding standard proposed by ITU-T SG 16 WP and ISO/IEC JTC 1/SC29/WG 11. In H.265, pictures are divided into a sequence of coding tree units(CTUs), and the CTU further is partitioned into multiple CUs to adapt to various local characteristics. Its coding efficiency is approximately two times high compared to previous standard H.264/AVC. However according to the size of extended CU(coding unit) and transform block, the hardware size of PMR(prediction/mode decision/reconstruction) block within video encoder is about 4 times larger than previous standard. In this study, we propose a new less complex hardware architecture of PMR block which has the most high complexity within encoder without any noticeable PSNR loss. Using this simplified block, we can shrink the overall size the H.265 encoder. For FHD image, it operates at clocking frequency of 300 MHz and frame rate of 60 fps. And also for the test image, the Bjøntegaard Delta (BD) bit rate increase about average 30 % in PMR prediction block, and the total estimated gate count of PMR block is around 1.8 M.