• 한국정보과학회논문지:시스템및이론
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• 제26권9호
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• pp.1112-1125
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• 1999

최근 들어 멀티미디어를 지원하는 응용들의 서비스 품질 보장과 멀티캐스트 지원에 대한 요구가 증가되고 있으나 기존의 멀티캐스트 프로토콜로는 이러한 요구를 수용할 수 없는 문제가 발생하고 있다. 현재 인터넷에서 사용되고 있는 라우팅 메커니즘은 네트워크 자원 정보나 세션의 QoS 요구사항을 고려하지 않고 단순히 종단간의 연결에만 초점을 맞추고 있기 때문이다. 따라서 본 논문에서는 멀티캐스트 환경에서 서비스 품질보장을 지원하기 위한 새로운 프로토콜, LayeredQoS을 제안한다. 다중의 CP (Central Point)를 채택하고 각각의 CP에 적절한 QoS 레벨을 부여하여 사용함으로써 대역폭의 공유정도를 높일 뿐만 아니라 전체 트리 비용을 감소시켜 궁극적으로 네트워크 처리량이 증가되도록 하였다. 또한 시뮬레이션 방법을 통하여 다른 프로토콜보다 나은 성능을 가지는 것으로 평가하였다.Abstract Many emerging multimedia applications often require a guaranteed quality of service and multicast connection. But the traditional multicast protocol can't meet the needs since the routing mechanisms deployed in today's Internet are focused on connectivity, not on resource availability in the network or QoS requirements of flows. In this paper, we present LayeredQoS, a new QoS-based multicast routing algorithm. We adopt the multiple CPs(Central Points) and allocate QoS-levels for each CP in order to improve the degree of resource sharing and decrease the total tree cost, and then network throughput is increased. The proposed protocol is verified by simulations and it is shown that the performance of LayeredQoS is much better than the existing protocols.

• Journal of Communications and Networks
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• 제8권1호
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• pp.85-92
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• 2006

In this paper, we study a wireless cellular network design problem. It consists of selecting the location of the base station controllers and mobile service switching centres, selecting their types, designing the network into a tree-topology, and selecting the link types, while considering the location and the demand of base transceiver stations. We propose a constraint programming model and develop a heuristic combining local search and constraint programming techniques to find very good solutions in a reasonable amount of time for this category of problem. Numerical results show that our approach, on average, improves the results from the literature.

• The Plant Pathology Journal
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• 제20권2호
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• pp.127-130
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• 2004

Grapevine leaf roll-associated virus 3 (GLRaV-3) is one of the most important viral diseases of grapevine in the world. In this study, GLRaV-3 Ampelovirus was identi-fied from grapevines in Korea by analyzing viral coat protein size, nucleotide, and amino acid sequences. The molecular weight of viral coat protein from virus-infected in vitro plantlets was determined by western blot using a commercial GLRaV-3 polyclonal antibody. Western blot analysis showed a coat protein of about 43 kDa. RT-PCR product of about 942 bp which encoded the coat protein (CP) gene was amplified with specific primers. When the viruses existed at low titers in the host plant, the dsRNA had very specific template in RT- PCR amplification of fruit tree viruses. Especially, small-scale dsRNA extraction method was very reliable and rapid. Sequence analysis revealed that the CP of the GLRaV-3 Ko consisted of 942 bp nucleotide, which encoded 314 amino acid residues. The CP gene of GLRaV-3 Ko had 98.9% nucleotide sequence and 98.7% amino acid sequence identities with earlier reported GLRaV-3. This is the first report on molecular assay of GLRaV-3 Ampelovirus identified from Korea. The GLRaV-3 Ko CP clone would be very useful for breeding of virus resistant grapevines.

• The Plant Pathology Journal
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• 제18권5호
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• pp.251-258
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• 2002

A potyvirus was isolated from cultivated Iris plants showing leaf streak mosaic symptom. Reverse transcription and polymerase chain reaction (RT-PCR) product of 1 kb long which encoded partial nuclear inclusion B and N-terminal region of viral coat protein (CP) genes for potyviruses was successfully amplified with a set of potyvirus-specific degenerate primers with viral RNA samples from the infected leaves: The RT-PCR product was cloned into the plasmid vector and its nucleotide sequences were determined. The nucleotide sequence of a CDNA clone revealed that the virus was an isolate of Ornithogalum moseic virus (OrMV) based on BLAST search analysis and was denoted as OrMV Korean isolate (OrMV-Ky). To further characterize the CP gene of the virus, a pair of OrMV-specific primers was designed and used for amplification of the entire CP gene of OrMV-Kr, The virus was easily and reliably detected from virus-infected Iris leaves by using the RT-PCR with the set of virus-specific primers. The RT-PCR product of the CP gene of the virus was cloned and its sequences were determined from selected recombinant CDNA clones. Sequence analysis revealed that the CP of OrMV-Kr consisted of 762 nucleotides, which encoded 253 amino acid residues. The CP of OrMV-Ky has 94.1-98.0% amino acid sequence identities (20 amino acid alterations) with that of other three isolates of OrMV, Two NT rich potential N-glycosylation motif sequences, NCTS and NWTM, and a DAC triple box responsible for aphid transmission were conserved in CPs of all the strains of OrMV. The virus has 58.5-86.2% amino acid sequence identities with that of other 16 potyviruses, indicating OrMV to be a distinct species of the genus. OrMV-Ky was the most related with Pterostylia virus Yin the phylogenetic tree analysis of CP at the amino acid level. This is the first report on the occurrence of OrMV in Iris plants in Korea. Data in this study indicate that OrMV is found in cultivated Iris plants, and may have mixed infection of OrMV and Iris severe mosaic virus in Korea.

• Tuberculosis and Respiratory Diseases
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• 제81권3호
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• pp.216-221
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• 2018

Background: The number of immigrants with tuberculosis (TB) increases each year in South Korea. Determining the transmission dynamics based on whole genome sequencing (WGS) to cluster the strains has been challenging. Methods: WGS, annotation refinement, and orthology assignment for the GenBank accession number acquisition were performed on two clinical isolates from Chinese immigrants. In addition, the genomes of the two isolates were compared with the genomes of Mycobacterium tuberculosis isolates, from two native Korean and five native Chinese individuals using a phylogenetic topology tree based on the Multiple Alignment of Conserved Genomic Sequence with Rearrangements (Mauve) package. Results: The newly assigned accession numbers for two clinical isolates were CP020381.2 (a Korean-Chinese from Yanbian Province) and CP022014.1 (a Chinese from Shandong Province), respectively. Mauve alignment classified all nine TB isolates into a discriminative collinear set with matched regions. The phylogenetic analysis revealed a rooted phylogenetic tree grouping the nine strains into two lineages: strains from Chinese individuals and strains from Korean individuals. Conclusion: Phylogenetic trees based on the Mauve alignments were supposed to be useful in revealing the dynamics of TB transmission from immigrants in South Korea, which can provide valuable information for scaling up the TB screening policy for immigrants.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.142-143
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• 2003

Ammi majus (white lace flower, Unbelliferae) is an ornamental plant used for cut-flower arrangements worldwide. A potyvirus was isolated from its leaves with mosaic and chlorotic symptoms in the cultivated field of Chiba, Japan. Compared with Japanese homuort mosaic virus (JHMV) previously isolated from Cryptotaenia japonica, it showed similar characteristics in host reactions and molecular properties. The nucleotide sequences of coat protein and 3'- nontranslated region were highly homologous and shared 87％ and 91％ identities with those of JHMV, respectively. This virus was thus supposed to be an isolate of JHMV and designated as JHMV-Am. Phylogenetic tree was constructed using CP nucleotide sequences of the two isolates and other potyviruses previously reported. JHMV-Am and JHMV fell into a cluster with Korean strain of Zantedeschia mosaic virus (ZaMV-KR). However, low identity in amino acid sequences was found in the termini of CP genes between the two isolates of JHMV and ZaMV-KR.

• The Plant Pathology Journal
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• 제20권2호
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• pp.147-154
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• 2004

A simple and reliable procedure for RT-PCR detection of Apple stem pitting virus (ASPV), Cherry rasp leaf virus (CRLV), and Cherry necrotic rusty mottle virus (CNRMV) was developed. Two virus specific primer sets for each virus were found to specifically detect each virus among fourteen sets of designed oligonucleotide primers. Total RNAs extracted from healthy and from ASPV-,CRLV- and CNRMV-infected plant tissues were used to synthesize cDNA using oligo dT primer and then amplified by virus-specific primers for each virus. Each primer specifically amplified DNA fragments of 578 bp and 306 bp products for ASPV (prAS CP-C and prAS CP-N primers, respectively); 697 bp and 429 bp products for CRLV (prCR4 and prCR5-JQ3D3 primers, respectively); and 370 bp and 257 bp products for CNRMV (prCN4 and prCN6-NEG 1 primers, respec-tively) by RT-PCR. DNA sequencing of amplified DNA fragments confirmed the nature of each amplified DNA. Altogether, these results suggest that these virus specific primer sets can specifically amplify viral sequences in infected tissues and thus indicate that they can be used for specific detection of each virus.

• The Plant Pathology Journal
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• 제23권4호
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• pp.245-250
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• 2007

The complete genome sequence of Zucchini yellow mosaic virus stain A (ZYMV-A) isolated from a hollyhock (Althaea rosea) was determined by using RT-PCR with a series of primer sets. The virus genome consisted of 9593 nucleotides (nt), excluding the poly(A) tract at 3' terminus of the virus genome, with 5' and 3' untranslated region of 139 and 211 nt, respectively. The deduced polyprotein of ZYMV-A consisted of 3080 amino acid (aa) residues and was 351 kDa in molecular weight. All proteolytic cleavage sites of the polyprotein of ZYMV-A were compared with those of ZYMV strains, which showed the cleavage sites were conserved among ZYMV strains. The HC-Pro contained the KITC and PTK motifs, and the DAG motif was located at CP ORF of ZYMV-A, suggesting that ZYMV-A is aphid-transmissible. Phylogenetic tree analysis based on the complete genome among ZYMV strains or CP ORFs with other potyviruses showed ZYMV strains formed a distinct group. These results clearly confirmed that ZYMV-A was another distinct strain in ZYMV population at molecular level.

• Journal of Ecology and Environment
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• 제37권1호
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• pp.21-29
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• 2014

Robinia pseudoacacia has become invasively naturalized in Japan. We investigated the role of sexual reproduction in the development of R. pseudoacacia riparian forests along the Chikumagawa River in Japan, by using five chloroplast (cpSSR) and seven nuclear (nSSR) markers. We identified eight chloroplast haplotypes and 147 nuclear genotypes from 619 R. pseudoacacia trees sampled in three plots (Plots A, B, and C) and along two line transects (Lines D and E). CpSSR analyses showed that multiple maternal lines were distributed along the river, and that some haplotypes from different populations overlapped. In addition, while Plots A and B were separated by a short distance, only these two plots exhibited genetic differentiation in the haplotypes. In the nSSR analysis, all pairwise $F_{ST}$ values among the three plots were significantly different from zero. Kinship analysis based on nSSR markers revealed that kinship connected many individuals to another individual from the same plot. These results indicate that seed dispersal near to mother trees contributes to the fine-scale genetic structure of R. pseudoacacia riparian forests. Our results indicate that sexual reproduction, in addition to asexual reproduction, is a major contributor to the fine-scale formation of R. pseudoacacia forests.

• The Plant Pathology Journal
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• 제18권6호
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• pp.317-322
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• 2002

An isolate of Odontoglossum ringspot virus (ORSV) was identified from Cymbidium var. 'Grace Kelly' showing ringspot symptom on the floral and leaf parts, and was denoted as cymbidium ringspot isolate (ORSV-CR). In ultrathin sections of leaf tissue from diseased Cymbidium plants, clusters of virus particles were observed in the vacuole and cytoplasm. In the Western blot hybridization, the virus strongly reacted with ORSV-specific antiserum indistinguishable from ORSV, suggesting that the vims is serologically identical with ORSV. ORSV-CR sap was inoculated onto 20 species belonging to 12 genera. Systemic infection occurred in Cymbidium sp., Nicotiana benthamiana and N. clevelandii, the host of which was found to be different from that of ORSV-Cy, the Korean strain of ORSV. The analysis of coat protein (CP) gene showed that ORSV-CR was highly homologous to the known isolates of ORSV, with over 95.6% identity in amino acid level. Phylogenetic tree analysis of CP showed that ORSV-CR was clustered with the known ORSV isolates, suggesting that ORSV is a very stable tobamovirus.