• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.1066-1070
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• 2001

The PhyA gene, encoding myo-inositol hexakisphosphate phosphohydrolase in Aspergillus niger var. awamori (wild-type), was cloned and sequenced. The cDNA was overexpressed by a multicopy gene expression system in Pichia pastoris KM71. Recombinant, wild-type and commercial phytase from Aspergilus ficuum NRRL 3135 (Natuphos) were purified. The PhyA gene of Aspergillus niger var awamori showed perfect homology to the phytase of Aspergillus ficcum and $97\%$ homology to A. niger var awamori (L02421). Wild-type phytase was highly glycosylated and more thermostable than the other two, while deglycosylated farms of three phytases showed identical molecular weight, 507 kDa. After heating at $80^{\circ}C$, wild-type, commercial, and recombinant phytases retained $57\%, 32%,\;and\;8\%$ of their original activities, respectively. In conclusion, glycosylation plays a key role in the thermostability of phytase and its enzymatic characterization.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7B
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• pp.780-788
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• 2011

The lack of QoS (Quality of Service) support functionalities in IEEE 802.11 DCF mode makes it difficult to provide real-time multimedia services in WLANs. In this paper, we propose an effective available bandwidth measurement method in IEEE 802.11b DCF environments. The proposed method measures the total channel idle time and the collision probability during each measurement period. Then, the available bandwidth is calculated by considering those measured information and the transmission overheads at MAC and PRY layers. The performances of the proposed method are evaluated using OPNET simulator. The simulation results show that the proposed method provides more exact results than existing comparable schemes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.9
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• pp.2107-2113
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• 2015

This paper proposed a Prior Forecast System of Crossroad Traffic Information that allows vulnerable road users to perceive traffic signal changes beforehand and respond in concentrated traffic areas such as crossroads. Also, it mapped out information linking procedures of the proposed system and it designed a PHY based wireless communication simulator to verify the operational feasibility of wireless communications. Conclusively, by conducting performance analysis according to crossroad channel environments using the simulator designed in this paper, it verified that a Prior Forecast System of Crossroads Traffic Information service for vehicle IT based decision-making support for vulnerable road users is a possibility.

• The Plant Pathology Journal
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• v.15 no.5
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• pp.287-294
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• 1999

A technique based on the polymerase chain reaction (PCR) for the specific detection of genus Phytophthora and Phytophthora cryptogea-P. drechsleri complex group was developed using nucleotide sequence information of ribosomal DNA (rDNA) regions. The internal transcribed spacers (ITS) including 5.8S were sequenced for P. cryptogea-P. drechsleri complex group and its related species. Two pairs of oligonucleotide primers were designed. Primer pair ITS1/Phy amplified ca. 240 bp fragment in 12 out of 13 specie of Phytophthora, but not in Pythium spp., Fusarium spp.and Rhizoctonia solani. Primer pair rPhy/Pcd amplified 549 bp fragment only in P. cryptogea-P. drechsleri complex group, but not in other Phytophthora spp.and other genera. Specific PCR amplification using the primers was successful in detecting Phytophthora and P. cryptogea-P. drechsleri complex group in diseased plants.

• Journal of Life Science
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• v.7 no.2
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• pp.127-133
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• 1997

The phytase(myo-inositol hexkisphosphate phosphohydrolase ; EC 3.1.3.8) activity was observed only in the homogenate of intestinal mucosa, though the activity of alkaline phisphatase was measurable in various organs. In addition, no protein bands were detected in any other organs on immunoblotting using the anti-90kDa phytase antiserum. Thses results suggest that phytase is specifically present in small intestinal mucosa, and that hydrolysis of phytic acid(inositol-hexakisphosphate) can be allotted for a physiological role of the intestine-specific enzyme. The activities of phytase was increased during development of rat. The 70kDa phytase appeared just after birth, but the 90kDa phytase was not observed until adult period, suggesting that the 90kDa phytase was synthesized in response to weanling.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.11 s.102
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• pp.1075-1085
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• 2005

The purpose of this paper is to design the architecture for synchronization of MB-OFDM UWB system that is being processed the standardization for Alt-PHY of WPAN(Wireless Personal Area Network) at IEEE802.15.3a and to analyze the implementation loss due to 4 parallel synchronization architecture for design or link margin. First an overview of the MB-OFDM UWB system based on IEEE802.15.3a Alt-PHY standard is described. The effects of non-ideal transmission conditions of the MB-OFDM UWB system including carrier frequency offset and sampling clock offset are analyzed to design a full digital architecture for synchronization. The synchronization architecture using 4-parallel structure is then proposed to consider the VLSI implementation including algorithms for carrier frequency offset and sampling clock offset to minimize the effects of synchronization errors. The overall performance degradation due to the proposed synchronization architecture is simulated to be with maximum 3.08 dB of the ideal receiver in maximum carrier frequency offset and sampling clock offset tolerance fir MB-OFDM UWB system.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.1
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• pp.35-42
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• 2022

Visible light communication (VLC) is a method of transmitting data through LED blinking and is vulnerable to eavesdropping because the illumination affects the wide range of area. IEEE standard 802.15.7 defines On-Off Keying (OOK), Variable Pulse Position Modulation (VPPM), and Color Shift Keying (CSK) as modulation. In this paper, we propose an encryption method in VPPM for secure communication. The VPPM uses an encoding method called 4B6B where 16 different outputs are represented with 6-bit. This paper extends the number of outputs to 20, to add complexity while not violating the 4B6B generation conditions. Then each entry in the extended 4B6B table is scrambled using vigenère cipher. The probability of decrypting each 6-bit data is $\frac{1}{20}$. Eavesdropper should perform $\sum\limits_{k=1}^{n}20^k$ number of different trials to decrypt the message if the number of keys is n. The proposed method can be applied to OOK of PHY II and CSK of PHY III. We further discuss the secure encoding that can be used in OOK and CSK without performance degradation.

• Information and Communications Magazine
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• v.30 no.9
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• pp.78-84
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• 2013

최근 4세대 이동통신은 기술/경제적인 이유로 클라우드 기지국 (또는 C-RAN: Cloud Radio Access Network) 구조를 택하는 추세이다. C-RAN은 기존 일체형 기지국에서의 MAC/PHY 기능을 담당하는 BBU(Base Band Unit)와 RF신호 송수신 만을 담당하는 RRH(Remote Radio Head)로 분리된 기지국 구조를 가지며, RRH의 무선 송수신 신호는 중앙의 BBU에 집중되어 처리된다. 본고에서는 BBU와 RRH로 분리되어 설치/운용되는 C-RAN의 구조와 기지국 가상화 개념을 소개하며, 향후 이동통신시스템에서의 기술동향과 관련하여 C-RAN에서 발생할 수 있는 이슈들을 살펴본다.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.115-116
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• 2009

Home-network gateway always powered on, while network data is not transferred. And the Power consumption of networked electric devices are greatly increased, to support higher speed data transfer. To reduce the power consumption of networked electric devices, some ideas were proposed. Such as ALR, Proxying, Subset-PHY. In this paper we propose a scheme to reduce power consumption of Home-Network Gateway. Proposed Home-network Gateway architecture consumes less than 1W in passive standby mode.

• Information and Communications Magazine
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• v.33 no.10
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• pp.17-23
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• 2016

본고에서는 저전력 단말이 infra 없이 device-to-device 로 주변 기기를 탐색하여 ad hoc으로 네트워크를 구성할 수 있는 피어 인지 통신용 (Peer Aware Communication: PAC) PHY와 MAC 개발을 목표로 하는 IEEE 802.15 Task Group 8의 표준화 동향을 소개하였다. IEEE 802.15 TG8은 2016년 6월 첫번째 Working Group Letter Ballot을 끝냈으며, RevCom 승인은 2017년 7월을 목표로 하고 있다.