• Journal of Microbiology and Biotechnology
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• v.31 no.7
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• pp.1022-1027
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• 2021

Three compounds were isolated from marine-derived Streptomyces sp. CNQ-031, and their inhibitory activities against monoamine oxidases (MAOs), acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and β-secretase (BACE-1) were evaluated. Compound 1 (5,7-dihydroxy-2-isopropyl-4H-chromen-4-one) was a potent and selective inhibitor of MAO-A, with a 50% inhibitory concentration (IC₅₀) of 2.70 µM and a selectivity index (SI) of 10.0 versus MAO-B. Compound 2 [5,7-dihydroxy-2-(1-methylpropyl)-4H-chromen-4-one] was a potent and low-selective inhibitor of MAO-B, with an IC₅₀ of 3.42 µM and an SI value of 2.02 versus MAO-A. Compound 3 (1-methoxyphenazine) did not inhibit MAO-A or MAO-B. All three compounds showed little inhibitory activity against AChE, BChE, and BACE-1. The K_i value of compound 1 for MAO-A was 0.94 ± 0.28 µM, and the K_i values of compound 2 for MAO-A and MAO-B were 3.57 ± 0.60 and 1.89 ± 0.014 µM, respectively, with competitive inhibition. The 1-methylpropyl group in compound 2 increased the MAO-B inhibitory activity compared with the isopropyl group in compound 1. Inhibition of MAO-A and MAO-B by compounds 1 and 2 was recovered by dialysis experiments. These results suggest that compounds 1 and 2 are reversible, competitive inhibitors of MAOs and can be considered potential therapies for neurological disorders such as depression and Alzheimer's disease.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.241-246
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• 2008

A nutritional supplement was developed aiming at correcting the most common nutrient and caloric deficiencies encountered in elderly people (${\geq}60$ years old). The protein source was a mixture of whey protein isolates (WPI) and bovine collagen hydrolysate (BCH) with high nutritional and functional qualities making up 12% of the formulation. The carbohydrate fraction was composed of sucrose, inulin (soluble fiber), and fructo-oligosaccharide (prebiotic). The most commonly deficient essential minerals and vitamins were also included. Acceptance of the product was good according to both an elderly panel and a laboratory panel composing of both sexes and various ages. The stability of the formulations was evaluated and the estimated shelf life at room temperature (ca. $27^{\circ}C$) was approximately 4 months.

• Journal of Digital Contents Society
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• v.7 no.4
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• pp.251-256
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• 2006

In this paper, We proposed joint-modulation CDMA system for efficient streaming transmission. and, We analyzed joint-modulation CDMA system using nakagami fading model and impulsive interference model for transmission channel environment. Also, it can being compensate the performance degradation by using MRC diversity scheme and BCH coding scheme.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.272-274
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• 2011

최근 들어 케이블 방송망을 기반으로 한 디지털 방송, VoIP(Voice over Internet Protocol), VOD(Video on Demand), 영상전화, 이동전화, 무선 랜 로밍 등의 다양한 멀티미디어 서비스의 출현과 향후 도입될 새로운 융합형 멀티미디어 서비스의 수용을 위해 케이블 망의 고도화에 대한 요구가 제기되었다. 특히 유럽을 중심으로 이러한 요구를 만족시키기 위해 DVB(Digital Video Broadcasting)-C2 규격의 개발이 진행되었다. DVB-C2 규격에서는 기존의 게이블 전송 규격인 DVB-C에 대해 30% 이상의 전송 효율을 높이고자 새로운 변조 방식과 채널 오류정정 부호 방식을 도입하였다. 이에 본 논문은 본 논문에서는 DVB-C2 규격에서 도입된 채널 오류정정 부호인 BCH(Bose, Chaudhuri, and Hocquenghem) 부호와 LDPC(Low Density Parity Check) 부호의 연접 방식에 대한 성능을 검증하고자 한다. 이를 위해 개발된 시뮬레이터의 소개와 이를 통한 시험결과를 제시한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.278-280
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• 2011

본 논문은 이미지가 갖는 R, G, B 비율의 분산을 이용하여, 공간 영역에서 정보를 은닉하는 알고리즘을 제시한다. 웹 상에서 Jpeg, bmp, gif 등의 포멧을 갖는 이미지를 raw 파일로 변환한 후, R,G,B 비율을 구한다. 그 중 사람의 눈에 가장 둔감한 B 비율 분산을 조작하여 정보를 은닉하는데 이용한다. 또한 오류율을 낮추기 위하여 (15,7)BCH Code 를 사용한다. 제안된 알고리즘이 JPEG(Joint Photographic coding Experts Group) compression, scale(이미지의 크기 변화), Mediancut 과 같은 이미지 변화에 강한 특성과 정보은닉 후에도 화질열화가 발생하지 않는 특성을 실험을 통해 보인다.

• Journal of Advanced Navigation Technology
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• v.13 no.4
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• pp.544-550
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• 2009

In this paper, we proposed the radio wave propagation characteristics of the next-generation ultrafast wireless communication system in millimeter-wave fading channel. For considering doppler shift and Rayleigh fading simultaneously, the fading simulator of Jakes model implemented and analyzed the performance of the next-generation wireless communication system. In addition, the error rate characteristics of DS-CDMA system analyzed in the millimeter-wave fading channel and the system performance improved by coding technique and diversity technique.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.7-10
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• 1998

The error performance of 16 Square-QAM signal with Optimum Threshold Detection(OTD) under the consideration of AWGN and Rician fading was analyzed for various value of Rician fading depth K. And error performance of 16-QAM signal with OTD, which considered in AWGN and Rician fading, was compared with that of 16-QAM signal with OTD, which considered in Rician fading only. And BCH coding is adopted. From the results, the error perfomance evlauated by proposed OTD was superior to that of 16-QAM signal with OTD, which considered in Rician fading without AWGN, in low CNR.

• Natural Product Sciences
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• v.18 no.4
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• pp.233-238
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• 2012

Nine compounds (1 - 9), ${\alpha}$-linolenic acid (1), cis-5,8,11,14,17-elcosapentaenoic acid (2), phytol (3), loliolide (4), uridine (5), thymidine (6), deoxyadenosine (7), adenine (8), and adenosine (9), were isolated from the n-hexane, methylene chloride, ethyl acetate and n-butanol fractions of Capsosiphon fulvescens. The structures of these compounds were elucidated on the basis of spectroscopic evidence. Compounds 1 - 9 exhibited acetylcholinesterase (AChE) inhibitory activities with $IC_{50}$ values ranging from 114.91 to $252.40{\mu}M$, whereas 2 - 4 showed butyrylcholinesterase (BChE) inhibitory activities with $IC_{50}$ values ranging from 251.18 to $499.16{\mu}M$.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.6
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• pp.821-828
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• 1990

A forward error correction (FEC) technique is presented for speech data in 16 Kbps digital mobile communications. 14Kbps SBC-APCM(AQB) and QPSK are used as speech coding and modulation techniques, respectively. Because each bit in a speech data block had different importance, applying FEC to speech data bit-selectively in more effective than applying FEC to all speech data equally. To select bits in a speech data block to be protected by FEC the bit error sensitivity of each bit is computed. For a few BCH and Reed-Solomon codes used as bit-selective FEC the performance of the coding technique is computed.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.373-376
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• 1999

In tills paper, we design it decoder for the FLEX high speed paging protocol. The decoder that we design consists of a synchronizer, a de-interleaver, a error corrector and a packet builder In the FLEX protocol, a word is coded using HCH algorithm. In this design, we do not use a look-up table in order to decrease a chip area of the BCH decoder. The simulation result shows that the decoder is correctly designed