• 한국정보통신학회논문지
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• 제8권3호
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• pp.517-522
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• 2004

본 논문에서는 마이크로웨이브 채널 환경에서 대역제한필터(BL-PSF)를 이용하는 OFDM/QPSK-DMR 시스템의 성능개선에 관한 연구를 수행하였다. 성능개선을 위해 단일적응등화기(one-tap adaptive equalizer)를 OFDM/QPSK-DMR 시스템에 적용하였으며, 단일 반송파방식의 DMR 시스템과 BER 및 특성 곡선(signature curve) 성능을 비교분석하였다. 시뮬레이션 결과 마이크로웨이브 채널 환경에서 OFDM/QPSK-DMR 시스템에 단일적응등화기를 적용한 경우, 부 반송파의 수가 16일때 단일 반송파방식의 DMR 시스템보다 2 dB 이상의 페이드 마진을 갖는다. 그리고 OFDM/QPSK-DMR 시스템의 부 반송파의 수가 많을수록 페이드 마진이 더욱 증가하여 성능이 향상 되는 것을 알 수 있었다.

• International Journal of Industrial Entomology and Biomaterials
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• 제4권2호
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• pp.109-115
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• 2002

With the objective of selecting suitable breeding resource material, 10 polyvoltine and 10 bivoltine breeds were drawn from the germplasm collection of Central Sericultural Research and Training Institute, Mysore, and evaluated for 3 seasons comprising one year (6 trials). Data were collected on seven traits of economic importance such as fecundity, pupation rate, cocoon yield, cocoon weight, cocoon shell weight, cocoon shell ratio and filament length, and statistically analysed with two-way classification, Joint scoring method and evaluation index. Significant seasonal variations (P < 0.01) were observed in both polyvoltine and bivoltine breeds. Polyvoltines BL27, BL36 and BL54 and bivoltines CSR2, CSR4 and Daizo scored highest ranking values in all the three methods. Hybridization was initiated based on larval markings and cocoon shapes. Seasonal variations were discussed.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.398-402
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• 2003

In this paper, we have analyzed the performance enhancement of OFDM/QPSK-DMR(Orthogonal Frequency Division Multiplexing/Quadrature Phase Shift Keying Modulation-Digital Microwave Radio)system using BL-PSF(Band Limited-Pulse Shaping Filter) over the microwave channel. For performance enhancement, we apply the one-tap adaptive equalizer for OFDM/QPSK-DMR system and compare with the BER performance of single carrier DMR system. Computer simulations confirm that the OFDM/QPSK-DMR system using one-tap adaptive equalizer has the same BER performance for the single carrier DMR system.

• 대한전자공학회논문지
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• 제22권5호
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• pp.45-49
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• 1985

자동이득 제어장치에서 신호대잡음비가 큰 신호나 중첩신호(ova.lapped signal)인 경우, 장치의 출력단에서 신호 감쇄가 일어나게 된다. 이런 문제점을 해결하기 위해 guasi-noise alone reference (QNAR)알고리즘이 발표 되었다. 그러나 이 QNAR 알고리즘을 계산의 복잡성 때문에 real time processing 이 어려운 단점을 가지고 있다. 본 논문에서는 이 문제점을 해결 하기위해 새로운 방법 즉 QNAR-Bl알고리즘을 제시 하였다. 제시된 QNAR-Bl 알고리즘은 계산의 복잡성을 대폭 감소시키면서도, 시abf레이션 결과 성능은 기존의 QNAR 알고리즘 보다 향상 되었다.

• 한국통신학회논문지
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• 제34권3B호
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• pp.255-263
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• 2009

본 논문에서는 IEEE 802.15.4 클러스터-트리 기반 LR-WPAN(Low Rate-Wireless Personal Area Network)에서 각 노드가 데이터량의 변화에 따라 실제 데이터 수신 구간을 조절하기 위한 적응적 Beacon 스케줄링 알고리즘을 제안한다. Beacon Interval을 짧게 조절하면, 노드는 일정한 시간동안에 더 많은 양의 데이터를 수신할 수 있다. 그러나 짧은 Beacon Interval을 가진 노드는 에너지 소비가 증가하게 되므로, 다시 수신할 데이터량이 줄어들면 Beacon Interval을 길게 조절함으로써 에너지 소비를 최적화시킨다. NS-2 시뮬레이터를 이용하여 검증한 결과, 제안하는 적응적 Beacon 스케줄링 알고리즘은 고정된 Beacon Interval을 사용하는 기법에 비해, 패킷 손실률과 End-to-End 전달 지연시간 측면에서 더 나은 성능을 보인다. 따라서 본 알고리즘과 결과는 향후 클러스터-트리 기반 LR-WPAN 설계 시, 서비스의 지연시간을 보장해야 하는 응용분야에 유용하게 사용될 수 있다.

• 대한전기학회논문지
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• 제39권1호
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• pp.92-106
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• 1990

Active compliance is often used in the control of robot manipulators for the implementation of complex tasks such as assembly, multi-finger fine motion, legged-vehicle adaptive control,etc. This technique balances the interactive force between the manipulator tip and its working environment with its position and velocity errors to achieve the operation of a damped spring. This paper investigates the effecft of passive compliance on system stability with regard to force feedback implementation for actively compliant motion. Usually it is understood that accurate position control require a stiff system. However, theoretical examination of control experiments on a legged suspension vehicle suggests that, if the control includes discrete-time force feedback, some passive compliance is necessssary at the legs of the vehicle for system stability. This can be an important factor to bl considered in manipulator design and control. A theoretical analysis, numerical simulation, and experimental result, confirming the above conclusion, are introduced in this paper.

• Journal of Microbiology and Biotechnology
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• 제24권11호
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• pp.1484-1489
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• 2014

A novel esterase gene, est01, was successfully unearthed from a biogas digester microbiota metagenomic library. The 1,194 bp est01 gene encodes a protein of 44,804 Da (designated Est01). The amino acid sequence of Est01 shows only moderate (33%) identity to a lipase/esterase. Phylogenetic analysis and biochemical characterization confirmed that Est01 is a new member of family VIII esterases. The purified Est01 from recombinant Escherichia coli BL21 (DE3) showed high hydrolytic activity against short-chain fatty acid esters, suggesting that it is a typical carboxylesterase rather than a lipase. Furthermore, the Est01 was even active at $10^{\circ}C$ (43% activity remained), with the optimal temperature at $20^{\circ}C$, and had a broad pH range from 5.0 to 10.0, with the optimal pH of 8.0. These properties suggest that Est01 is a cold-adaptive esterase and could have good potential for low-temperature hydrolysis application.

• Biomolecules & Therapeutics
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• 제23권4호
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• pp.345-349
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• 2015

Betulinic acid, a pentacyclic triterpene isolated from Jujube tree (Zizyphus jujuba Mill), has been known for a wide range of biological and medicinal properties such as antibacterial, antimalarial, anti-inflammatory, antihelmintic, antinociceptive, and anticancer activities. In the study, we investigated the antiviral activity on influenza A/PR/8 virus infected A549 human lung adenocarcinoma epithelial cell line and C57BL/6 mice. Betulinic acid showed the anti-influenza viral activity at a concentration of $50{\mu}M$ without a significant cytotoxicity in influenza A/PR/8 virus infected A549 cells. Also, betulinic acid significantly attenuated pulmonary pathology including increased necrosis, numbers of inflammatory cells and pulmonary edema induced by influenza A/PR/8 virus infection compared with vehicle- or oseltamivir-treated mice in vivo model. The down-regulation of IFN-${\gamma}$ level, which is critical for innate and adaptive immunity in viral infection, after treating of betulinic acid in mouse lung. Based on the obtained results, it is suggested that betulinic acid can be the potential therapeutic agent for virus infection via anti-inflammatory activity.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권8호
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• pp.4092-4104
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• 2017

In this paper, an efficient 4K and 8K UHD(Ultra High Definition) transmission scheme is proposed on the convergence networks with broadcasting and LTE(Long Term Evolution) by using CoMP(Coordinated Multi-Point). A video data is compressed and divided into BL(Base Layer), E(Enhanced layer)1, E2 and E3 by scalable HEVC(High Efficiency Video Coding). The divided layers can be combined by the scalable HEVC such as mobile HD, full HD, 4K and 8K UHD(Ultra High Definition). The divided layers are transmitted through the convergence networks with DVB-T2(Digital Video Broadcasting-$2^{nd}$ Generation Terrestrial) broadcasting system and LTE CoMP. This scheme transmits mobile HD and full HD layers through DVB-T2 broadcasting system by using M-PLP(Multiple-physical Layer Pipes), and adaptively transmits 4K or 8K UHD layer through LTE CoMP with MMT(MPEG Media Transport) server. An adaptive transmitting and receiving scheme in the LTE CoMP system provides 4K or 8K UHD layer to a user according to the user status. The proposed scheme is verified by showing the system-level simulation results which is better BER(bit-error-rate) performance than the conventional scheme. The results show that the proposed scheme provides the stable video contents to the user especially at the cell edge.