• Proceedings of the KIEE Conference
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.450_451
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• 2009

최근 부하증가에 대한 안정적 전력공급과 환경문제 해결은 전 세계적 이슈로 등장되고 있으며, 그 해결책으로써 분산형전원(Distributed generation, DG)에 대한 관심이 높아지고 있다. DG는 경제적 효율적 이유로 기존 전력계통과 연계해 운전되는데, 태양광이나 풍력과 같은 재생에너지를 이용한 DG의 불확실하며 빈번한 출력변동은 배전계통의 전압조정을 어렵게 만든다. 배전계통의 전압조정을 위해 배전용변전소의 부하시 탭 변환기(Under Load Tap Changer, ULTC)가 이용되고 있다. ULTC는 부하변동에 따른 배전선로상 전압강하를 보상하는 선로 전압강하보상법(Line Drop Compensation, LDC)에 의해 조정된다. LDC 전압조정법에서, 측정된 뱅크전류와 미리 설정된 LDC 정정치(LDC parameters, 부하중심점 전압과 등가 임피던스)를 이용해 ULTC의 송출전압을 결정한다. LDC 정정치 설계시, 기존에는 ULTC 탭 동작횟수를 줄이는 것이 주요 목표였고, 이 목표는 DG 도입을 제한하는 큰 원인이 되고 있다. 그러므로 본 논문에서는 DG 도입을 증가시키는 새로운 ULTC 전압조정법을 제시하고 모델 배전계통 시뮬레이션을 통해 그 유효성을 확인한다.

• Journal of the Institute of Electronics and Information Engineers
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• 제50권7호
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• pp.140-148
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• 2013

This paper presents a iterative Bose-Chaudhuri-hocquenghem (i-BCH) code and its high-speed decoder architecture for 100 Gb/s optical communications. The proposed architecture features a very high data processing rate as well as excellent error correction capability. The proposed 6-iteration i-BCH code structure with interleaving method allows the decoder to achieve 9.34 dB net coding gain performance at $10^{-15}$ decoder output bit error rate to compensate for serious transmission quality degradation. The proposed high-speed i-BCH decoder architecture is synthesized using a 90-nm CMOS technology. It can operate at a clock frequency of 430 MHz and achieve a data processing rate of 100 Gb/s. Thus, it has potential applications in next generation forward error correction (FEC) schemes for 100 Gb/s optical communications.

• Journal of the Institute of Electronics Engineers of Korea SP
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• 제47권3호
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• pp.23-31
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• 2010

The increasing demands on low-power, and low-complexity video encoder have been motivating extensive research activities on distributed video coding (DVC) in which the encoder compresses frames without utilizing inter-frame statistical correlation. In DVC encoder, contrary to the conventional video encoder, an error control code compresses the video frames by representing the frames in the form of syndrome bits. In the meantime, the DVC decoder generates side information which is modeled as a noisy version of the original video frames, and a decoder of the error-control code corrects the errors in the side information with the syndrome bits. The noisy observation, i.e., the side information can be understood as the output of a virtual channel corresponding to the orignal video frames, and the conditional probability of the virtual channel model is assumed to follow a Laplacian distribution. Thus, performance improvement of DVC systems depends on performances of the error-control code and the optimal reconstruction step in the DVC decoder. In turn, the performances of two constituent blocks are directly related to a better estimation of the parameter of the correlation channel. In this paper, we propose an algorithm to estimate the parameter of the correlation channel and also a low-complexity version of the proposed algorithm. In particular, the proposed algorithm minimizes squared-error of the Laplacian probability distribution and the empirical observations. Finally, we show that the conventional algorithm can be improved by adopting a confidential window. The proposed algorithm results in PSNR gain up to 1.8 dB and 1.1 dB on Mother and Foreman video sequences, respectively.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제18권5호
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• pp.111-116
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• 2018

This paper introduces the concept of a random universal hash function to amplify security in a quantum key distribution system. It seems to provide security amplification using the relationship between quantum error correction and security. In addition, the approach in terms of security amplification shows that phase error correction offers better security. We explain how the universal hash function enhances security using the BB84 protocol, which is a typical example of QKD(Quantum Key Distribution). Finally, we show that the BB84 protocol using random privacy amplification is safe at higher key rates than Mayers' performance at the same error rate.

• (The) Research of the performance art and culture
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• 제36호
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• pp.75-102
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• 2018

Manjungpan Chunhyangga is established by Manjung Kim Sohee. She selectively chose and arranged the songs by Jung Jungryeol, Song Mangap, Jung Eungmin, Kim Yeonsoo, Park Dongsil, and Jung Kwangsil. Kim Sohee once stated that while a major section of Chunhyangga is based on the songs by Jung Jungryeol, Song Mangap, Jung Eungmin, and Kim Yeonsoo, the whole part of Okjungga is derived from Park Dongsil. However, there is not much material that will provide enough information with regard to what musical characteristics Park Dongsilje Chunhyangga possessed. Under the circumstances, the voice of Park Dongsilje, left by Kim Sohee, triggers curiosity on Park Dongsilje Chunhyangga. It can also be construed that there must be a good reason for choosing Park Dongsilje for Okjungga, unlike other parts. Therefore, this paper attempted to find out what the unique features of Par Dongsilje are and what the reasons behind Kim Sohee's musical choice were through comparison and analysis of Kim Sohee's musical features in Okjungga. The following are the results. Firstly, Okjungga is a created verse by its nature and it does not possess specific features to a school. Therefore, the reason for choosing Park Dongsilje could have been based on musical reason rather than verse. Secondly, the lyrics of Park Dongsilje Okjungga is closer to that of Song Mangap rather than that of Jung Jungryeolje. It can be argued that it falls between the two of them. Thirdly, the tone and melody of Park Dongsilje Okjungga falls in the middle section of Dongpyenje and Supyenje. Fourthly, the analysis of Jinyangjo rhythm out of the whole Manjungpan Chunhyangga shows that there are slight differences among Song Mangapje, Jung Jungryeolje, and Jung Eungminje. Park Dongsilje is very unique in the sense that it does not use utbutim in gyemyeonjo part in Manjungpan Chunhyangga. Park Dongsilje Okjungga is a song to which the tone, melody, and sigimsae of Supyeonje is added to lyric butimsae of Dongpyeonje. It can be seemed as simple and less sophisticated because, with its simple lyric butimsae, it shows a less complicated tone utilization rather than Jung Jungryeol. With lighter decoration of music, feelings can be conveyed more directly. That is probably why Kim Sohee commented on Park Dongsilje Chunhyangga that it is the most mournful song for Chunhyang and it is the song that moves anyone who listens to the song. Consequently, Kim Sohee accepted Park Dongsilje Okjungga and she created different feelings to Manjungpan Chunhyangga which has repeatedly displayed the color of Jung Jungryeol. Combining the lyric addition of Dongpyeon style and the melody of Supyeon style can crated a different language.

• Journal of IKEEE
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• 제23권4호
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• pp.1288-1294
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• 2019

The channel-achieving property made the polar code show to advantage as an error-correcting code. However, sufficient error-correction performance shows the asymptotic property that is achieved when the length of the code is long. Therefore, efficient architecture is needed to realize the implementation of very-large-scale integration for the case of long input data. Although the most basic fully parallel encoder is intuitive and easy to implement, it is not suitable for long polar codes because of the high hardware complexity. Complementing this, a partially parallel encoder was proposed which has an excellent result in terms of hardware area. Nevertheless, this method has not been completely generalized and has the disadvantage that different architectures appear depending on the hardware designer. In this paper, we propose a hardware design scheme that applies the proposed systematic approach which is optimized for bit-dimension permutations. By applying this solution, it is possible to design a generalized partially parallel encoder for long polar codes with the same intuitive architecture as a fully parallel encoder.

• Journal of the Institute of Electronics Engineers of Korea SP
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• 제41권1호
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• pp.77-82
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• 2004

In this paper we present a barcode reader to decode two-dimensional symbology PDF417 and propose a novel method to extract the bar-space Patterns directly from the gray-level barcode image, which employs the location and the distance between extreme points of each row or column of the barcode image. This algerian proves to be very robust from the high convolutional distortion environments such as defocussing and warping, even under badly illuminating condition. If the scanned barcode image is a result of the convolution of a Gaussian-shaped point spread function with a hi-level image, popular image segmentation methods such as image thresholding can not distinguish between very narrow bar-space patterns. The Proposed algorithm shows improved Performance over current barcode readers.

• Journal of the Institute of Electronics and Information Engineers
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• 제49권11호
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• pp.3-8
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• 2012

Two-dimensional product code has been studied for correcting burst errors on the storage systems. An RS-LDPC product code consists of an RS code in horizontal direction and an LDPC code in vertical direction. First, we detect the position of burst errors by using RS code, then LDPC code corrects the errors by using the burst error positions. In storage system, long burst errors are occurred by various reason. So, we need a strong code for correcting the long burst errors. RS-LDPC product code is good for long burst errors. However, as the storage density grows the length of the burst errors will be longer. Thus, we propose an LDPC-LDPC product code, it is strong for correcting the very long burst errors. Also, the proposed LDPC-LDPC product code performs better than RS-LDPC product code when the random errors are occurred, because a row direction LDPC code performs better than row direction RS code.

• The KIPS Transactions:PartC
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• 제9C권4호
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• pp.563-572
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• 2002

Wireless mobile networks tend to drop a large portion of packets due to propagation errors rather than congestion. To Improve reliability over noisy wireless channels, wireless networks can employ forward error correction (FEC) techniques. Static FEC algorithms, however, can degrade the performance by poorly matching their overhead to the degree of the underlying channel error, especially when the channel path loss rate fluctuates widely. This paper investigates the benefits of an adaptable FEC mechanism for wireless networks with severe packet loss by analytical analysis or measurements over a real wireless network called sensor network. We show that our adaptive FEC named FECA (FEC-level Adaptation) technique improves the performance by dynamically tuning FEC strength to the current amount of wireless channel loss. We quantify these benefits through a hybrid simulation integrating packet-level simulation with bit-level details and validate that FECA keeps selecting the appropriate FEC-level for a constantly changing wireless channel.

• Journal of Satellite, Information and Communications
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• 제12권4호
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• pp.152-156
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• 2017

This paper introduces the concept of random security amplification to amplify security in a quantum key distribution system. It seems to provide security amplification using the relationship between quantum error correction and security. In addition;we show that random security amplification in terms of security amplification offers better security than using existing universal hash function. We explain how the universal hash function enhances security using the BB84 protocol, which is a typical example of QKD. Finally, the proposed random security amplification and the conventional scheme compare the security according to the key generation rate in the quantum QKD.