• 한국멀티미디어학회논문지
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• 제12권9호
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• pp.1191-1200
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• 2009

그리드 데이터 베이스에서 복제본 데이터는 응용 서비스 제공을 위한 기반 정보로서 활용되며, 응용 서비스의 종류, 정보의 특성에 따라 각각의 복제본에 대한 접근 빈도에 차이가 발생한다. 특히 많은 노드에 복제본이 저장됨으로 인해 그리드 컴퓨팅 환경에서의 각각의 복제본을 관리하는 연구가 계속 되고 있다. 그의 일환으로 접근 빈도를 기반으로 한 데이터 갱신 기법이 있으며, 복제본 노드의 접근 빈도를 기반으로 데이터를 갱신한다. 하지만 동적인 접근에 대한 고려가 부족하여 그리드 환경에는 부적합하다. 따라서 본 논문에서는 갱신 정보를 관리하기 위한 동적 접근 빈도 트리를 이용한 갱신 기법을 제안한다. 동적 접근 빈도 트리는 접근 빈도를 통하여 미리 각 노드를 그룹단위로 묶어 트리를 구축하며, 또한 트리의 불균형으로 인하여 성능이 저하되는 것을 방지한다. 제안 기법은 성능평가를 통해 빠른 갱신을 보임으로써 기존의 기법에 비하여 향상된 성능을 보인다.

• Journal of Microbiology and Biotechnology
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• 제12권3호
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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.

• 생명과학회지
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• 제11권4호
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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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• 제5권3호
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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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• 제29권6호
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• pp.531-537
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• 2006

본 연구는 월악산 국가장기생태연구지소를 중심으로 이 지역에서 다른 개체군에 비하여 상대적으로 광역 우점하는 소나무림, 굴참나무림, 그리고 신갈나무림 등 3개 주요 임분을 대상으로 그들의 종조성과 구조적 특성을 평가하였다. 종 및 개체수는 분포 경향은 흉고직경급이 증가할수록 감소하는 경향을 나타내었으며, 종 풍부성에 있어서 다양한 입지 적응 폭을 가지고 있는 신갈나무림이 다른 두 임분에 비하여 상대적으로 높게 나타남을 알 수 있었다. 천이 경향은 임분별로 천이 단계상 다소 차이가 있지만 장기적으로 보면 임분 유형에 관계없이 모두 신갈나무림으로 변화될 것으로 판단되었다. 각 임분의 우점종을 기준으로 생목과 사목의 개체 밀도 구성비를 보면 신갈나무림에서 신갈나무 개체 75:25, 굴참나무림에서 굴참나무 개체 94:6, 그리고 소나무림에서 소나무 86:14로 신갈나무림에서 개체 고사율이 가장 높고 굴참나무림이 가장 낮게 나타났다. 이것은 각 임분의 천이 단계의 차이에 따른 종간 및 종내 경쟁의 결과로 판단되었다. 한편, 임분별 구성 개체목의 건강 상태를 보면 임분유형에 관계없이 AS형이 75$\sim$85%로 가장 높게 나타났으며 DF형은 전혀 나타나지 않았다. 끝으로 본 연구를 위해 설치한 영구 방형구는 향후 정기적인 조사를 통하여 이 지역 산림 생태계 보전에 적합한 유용 정보를 제공하여 줄 수 있을 것이다.

• 한국통신학회논문지
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• 제13권5호
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• pp.390-399
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• 1988

계산 과장이 비교적 간단하고 실시간 처리가 가능한 coding방법 중의 하나인 BTC(Block Truncation Coding)를 이용하여 영상 데이터를 압축하기 위하여 2진 영상에서 주로 사용하는 quar tree 개념을 도입하여 압축율을 개선시키고, 기존의 BTC와 그 성능을 비교하였다. 이 논문에서 제안하는 방법은 그레이 레벨의 변화가 적은 영역에서는 부화상의 크기를 크게 하고, 그레이 레벨의 변화가 큰 영역에서는 부화상의 크기를 작게 하여 전체 부화상의 갯수를 줄임으\ulcorner\ulcorner영상 데이타의 압축을 행하였다. 또한 비트 평면의 효율적인 전송을 위하여 큰 크기의 부화상에 있어서는 Huffman run-length code를, 작은 크기의 부화상에 있어서는 lookup rable방식을 이용하였다. 컴퓨터 시뮬레이션 결과, 크기가 256x256이고, 그레이 레벨이 256인 영상에서 평균 0.8bit/pel의 압축 효과를 얻었다.

• Animal Systematics, Evolution and Diversity
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• 제34권1호
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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.

• 한국환경과학회지
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• 제25권1호
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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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• 제6권2호
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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.

• 유공압시스템학회논문집
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• 제2권2호
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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.