• Journal of Korea Multimedia Society
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• v.12 no.9
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• pp.1191-1200
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• 2009

The replicas in the Grid database is utilized for a lot of application services. And for deferent services or for deferent information depends on location, the access frequency of each replica is dissimilar. When one replica is stored in many nodes, each replicas applies the week-consistency in the grid computing environment. Especially, when a node work load or operation capacity is varied from others, the replica management would cost expansive. Therefore, this paper proposed the Update Method based on Dynamic Access-Frequency Tree. The dynamic access-frequency tree is pre-constructed by grouping nodes based on each nodes access frequency to manage the replica efficiently and avoid unbalance replica tree. The performance evaluation shows the proposed methods support more quick update than current methods.

• Journal of Microbiology and Biotechnology
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• v.12 no.3
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• pp.508-513
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• 2002

Human endogenous retroviral long terminal repeats (LTRs) have been found to be coexpressed with sequences of genes located nearby. It has been suggested that the LTR elements have contributed to the structural change or genetic variation of human genome connected to various diseases. The HERV-W family has been identified in the cerebrospinal fluids and brains of individuals with schizophrenia. Using a cDNA library derived from a human brain, the HERV-W LTR elements were examined and five new LTR elements were identified. These elements were examined using a YAC clone panel from the Xq21.3 region linked to psychosis that was replicated on the Y chromosome after the separation of the chimpanzee and human lineages. Fourteen elements of the HERV-W LTR were identified in that region. Those LTR elements showed a high degree of sequence similarity ($91.8-99.5\%$) with previously reported HERV-W LTR. A phylogenetic tree obtained from the neighbor-joining method revealed that new HERV-W LTR elements were closely related to the AXt000960, AF072504, and AF072506 from the GenBank database. The data indicates that several copy numbers of the HERV-W LTR elements exist on the Xq21.3 region and are also expressed in the human brain. These LTR elements need to be further investigated as potential leads to neuropsychiatric diseases.

• Journal of Life Science
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• v.11 no.4
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• pp.379-384
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• 2001

Long terminal repeats(LTRs) of the human endogenous retrovirus(HERV) heve been found to be coexpresed with genes located nearby. It has been suggested that the LTR elements have contributed to the genetic variation of human genome connected to various diseases. Recently, HERV-W family was identified in the cerebrospinal fluids and brains of individuals with schizophrenia. Using cHNA library derived from human fetal brain, we performed PCR amplification and identified seven new HERV-W LTR elements. Those LTR elements showed a high degree of sequence similarity(98∼99%) with HERV-W (AF072500). A phylogentic tree obtained by the neighbor-joining method revealed that seven new HERV-W LTR elements(FB-1, 2, 4, 8, 9, 10, 12) were closely related to the AX000960, AF072504, and AF072506 from Gen Bank database. Our data suggest that several copy numbers of the HERV-W LTR elements are expressed in human feta brain and may contribute to an understanding of biological function connected to neuropsychiatric diseases.

• Animal cells and systems
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• v.5 no.3
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• pp.243-246
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• 2001

Human endoqenous retroviral long terminal repeats (LTRs) have been found to be coexpressed with sequences of genes closely located nearby. It has been suggested that the LTR elements have contributed to structural changes or genetic variations of human genome connected to various diseases and evolution. Using cDNA library derived from placenta tissue, we performed PCR amplification and identified five new HERV-W LTR elements. Those LTR elements showed a high degree of sequence similarity (98-99%) with HERV-W LTR (AF072500). A phylogenetic tree obtained by the neighbor-joining method revealed that HERV-W LTR elements could be mainly divided into two groups through evolutionary divergence. Five new HERV-W LTR elements (pla-1, 4, 5, 6, 7) belonged to the group I with AX000960, AF072504, and AF072506 from GenBank database. The data suggest that several copy numbers of the HERV-W LTR elements are transcribed in placenta and may contribute to the understanding of biological function such as human placental morphogenesis.

• Journal of Ecology and Environment
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• v.29 no.6
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• pp.531-537
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• 2006

We assessed the species composition and structure of the three representative forest stands(Pinus densiflora stand, Quercus variabilis stand, and Ouercus mongolica stand), dominated in the National Long-Term Ecological Research Sites of Mt. Worak, Korea and established a benchmark series of permanent plots and transects with which future changes in forest composition and structure could be monitored. Species richness of Q. mongolica stand was greater than other two stands, due in large part to the greater habitat heterogeneity. Number of trees and species are decreased with increasing DBH classes. The successional trends of the three study stands would be mostly changed as Q. mongolica forest, regardless of forest types. Mean density ratio between alive trees and dead trees of three forest stands appeared with Q. mongolica stand 75:25, Q. variabilis stand 94:6, and P. densiflora stand 86:14, Q. mongolica stand appeared most highly from in three stands. This may be due to interspecific or intraspecific competition that it follows in various successesional stages. One side, when it saw the tree status which shows the tree health, the three forest stands all standing alive type (AS) appeared most highly with 75% to 85% and fallen dead type (DF) did not appear entirely. Remeasurement of permanent plots at periodic intervals will provide useful information on the dynamics of the forest vegetation that can be used in the development of adaptive conservation plans.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.5
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• pp.390-399
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• 1988

A conventional BTC has the merit of real time processing and simple computation, but has the problem that its compression rate is low. In this paper, a modified BTC using the Quad Tree which is frequently used in binary image is proposed. The method results in the low compression rate by decreasing the total number of subblocks by mean of making the size of a subblock large in the small variation area of graty level and the size af a subblock small in the large variation area of gary level. For the effective transmission of bit plane, the Huffman run-lengh code for the large size of a subblock and the lookup table for tha small size of a subblock are used. The proposed BTC method show the result of coding 256 level image at the average data rate of about 0.8 bit/pixel.

• Animal Systematics, Evolution and Diversity
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• v.34 no.1
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• pp.37-49
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• 2018

Two hypotrich ciliates, Australocirrus shii (Shi et al., 1997) Kumar & Foissner, 2015 and Afrokeronopsis aurea (Foissner & Stoeck, 2008) Foissner et al., 2010 isolated from freshwater habitats in Korea and were studied based on the specimens from live and after protargol impregnation. Australocirrus shii is redescribed based on morphology and 18S rRNA gene sequence, whereas Af. aurea is the first record for Korea. Main morphological features of the Korean population of Au. shii are as following: body size $100-200{\times}40-80{\mu}m$ in vivo; elongate to ellipsoidal or slightly elongate obovate, dorsoventrally flattened; transverse cirri arranged in (3+2) pattern, anterior pretransverse ventral cirrus distantly anterior of the first transverse cirrus; eight or nine dorsal kineties; and three caudal cirri. Main morphological features of the Korean population of Af. aurea are as following: body size $230-375{\times}70-145{\mu}m$ in vivo; shape elongate obovate or ellipsoidal, widest at the mid-body; undulating membranes in Australocirrus pattern with a buccal depression; and three caudal cirri. The Korean population of A. shii is similar in morphology with previous descriptions except for the presence of indentation at the posterior end in the Korean population. The Korean population of A. aurea is slightly shorter than the South African population and has slightly less marginal and mid-ventral cirri. The phylogenetic analysis of present two Korean hypotrichs and relevant species based on 18S rRNA gene sequences generated almost similar tree topologies compared with previous studies.

• Journal of Environmental Science International
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• v.25 no.1
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• pp.57-65
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• 2016

This study's purpose was to provide basic data for the monitoring of ecological changes caused by change of vegetation structure of Abies koreana forest in a study site susceptible to climatic change in Yeongsil area of Hallasan Mountain, Jeju Island. Surveys revealed this: in Yeongsil area of Hallasan Mountain, per 1 ha of A. koreana forests, total number 1,781, and A. koreana number 989, accounting for 55.5% of the total number of trees. 190 A. koreana or 19.2% were found to be dead. For the number of individual trees by DBH, trees standing 5 cm - 10 cm tall formed the largest portion at 39.9%, and in the case of other trees except A. koreana, the number of individual trees below 5 cm accounted for 23.5% of the total number of trees. The survey of importance by height revealed this: at the top level, the importance of A. koreana was the highest at 106.23, but the sum of importance of temperate deciduous broad-leaved trees (Prunus maximowiczii, Quercus mongolica, and Taxus cuspidata) was higher at 142.84 than that of A. koreana. The analysis of species diversity revealed 0.645 species diversity for the tree layer and 0.817 for the shrub layer; for evenness, 0.549 for the tree layer and 0.664 for the shrub layer; for dominance value; 0.451 for the tree layer and 0.336 for the shrub layer. The analysis of tree vitality revealed that for the A. koreana forests in Yeongsil, the composition ratio of A. koreana by type is AS type>AL type>DS type>DB type, and that of the other trees is AL type>AS type>AF type>AB type. Compared with the forests in other areas, the A. koreana forests in the Yeongsil area have a very high occurrence rate of dead trees, and a high importance of trees is shown in the deciduous broad-leaved tree forests. Compared with the A. koreana forests in the Jindallaebat area, with the same level above sea, the vegetation structures are fast changing. Also, due to dryness and other non-physical environmental changes caused by a lack of rainwater and dry winds in winter, dead trees are fast increasing in number. Environmental changes such as climate change diversely affect the maintenance of A. koreana in individual areas, and if environmental changes are fast and continue long, of the A. koreana forest areas in the Hallasan Mountain, the A. koreana forests in the Yeongsil area will decrease fastest in number and will experience changes in the vegetation structure. Thus, it is necessary to survey the vegetation changes in A. koreana forests, which are distributed in all directions but are centered on Hallasan Mountain, and to thus conduct long-term monitoring and research.

• Animal cells and systems
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• v.6 no.2
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• pp.167-170
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• 2002

The long terminal repeats (LTRs) of human endogenous retrovirus (HERV) have been found to be coexpressed with sequences of closely located genes. It has been suggested that the LTR elements have contributed to the structural change or genetic variation of human genome connected to various diseases and evolution. We examined the HERV-W LTR elements in various cancer cells (2F7, A43l , A549, HepG2, MIA-PaCa-2, PC-3, RT4, SiHa, U-937, and UO-31). Using genomic DNA from the cancer cells, we performed PCR amplification and identified twelve new HERV-W LTR elements. Those LTR elements showed a high degree of sequence similarity (88-99％) with HERV-W LTR (AF072500). A phylogenetic tree obtained by the neighbor-joining method revealed that HERV-W LTR elements could be mainly divided into two groups through evolutionary divergence. Three HERV-W LTR elements (RT4-2, A43l-1, and UO3l-2) belonged to Group 1, whereas nine LTR elements (2F7-2, A549-1, A549-3, HepG2-3, MP2-2, PC3-1, SiHa-8, SiHa-10, and U937-1) belonged to Group 11. Taken together, our new sequence data of the HERV-W LTR elements may contribute to an understanding of tissue-specific cancer by genomic instability of LTR integration.

• Transactions of The Korea Fluid Power Systems Society
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• v.2 no.2
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• pp.1-7
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• 2005

For the reliability evaluation of the track drive unit(TDU), firstly, we analyzed the major failure modes through FMEA(failure mode & effects analysis), FTA(failure tree analysis), and 2-stage QFD(quality function deployment), and then quantitatively determined the priority order of test items. The Minitab analysis was also performed for prediction of life distribution and parameters of TDU by use of field failure data collected from 430 excavators for two years. In addition, we converted the fluctuation load in field conditions into the equivalent load, and for evaluation of the accelerated lift by the cumulative fatigues, the equivalent load is again divided into the fluctuation load by reference of test time. And then, by use of the test method in this paper, the acceleration factor(AF) of needle bearing inside planetary gear which is the most weakly designed part of TDU is achieved as 5.3. This paper presents the quantitative selection method of test items for reliability evaluation, the determination method of the accelerated life test time, and the method of non-failure test time based on a few of samples. And, we proved the propriety of the proposed methods by experiments using a TDU for a 30 ton excavator.