• The Korean Journal of Ecology
• /
• v.23 no.5
• /
• pp.407-421
• /
• 2000

The forest vegetation surrounding Taegu area was investigated by the methodology of the ZM school of phytosociology, from September, 1994 to August, 1997. The forest vegetation was classified into 7 communities, 8 subcommunities and 5 afforestations as follows : Quercus mongolica community (Typical subcommunity, Carex siderosticta subcommunity), Quercus variabilis community, Quercus acutissima community, Quercus dentate community, Carpinus cordata-Acer mono community (Typical subcommunity, Quercus serrata subcommunity, Cornus controversa subcommunity), Pinus densiflora community (Typical subcommunity, Sanguisorba officinalis subcommunity, Rhododendron schlippenbachii subcommunity), Lespedeza maximowiczii-Rhododendron mucronulatum community , Robinia pseudo-acacia afforestation, Pinus rigida afforestation, Larix leptolepis afforestation, Pinus thunbergii afforestation, Pinus koraiensis afforestation. The differential species of the Quercus mongolica community were Quercus mongolica, Athyrium yokoscense, Rhododendron schlippenbachii, Fraxinus sieboldiana, Acer pseudo-sieboldianum, Symplocos chinensis for. pilosa, Astilbe chinensis var. davidii, Weigela subsessilis, and Melampyrum roseum, those of the Carpinus cordata-Acer mono community were Acer mono, Carpinus cordata, Carpinus laxiflora, and Staphylea bumalda, those of the Pinus densiflora community were Pinus densiflora, Quercus serrata, Cocculus trilobus, and Juniperus rigida. Constance degree of the Quercus serrate was especially high in shrub and herb layers of the Pinus densiflora community. The results of factor analysis by DCA showed that distribution pattern of the communities were similar to that by Z-M method and that communities were arranged according to soil moisture gradient. Rhododendron schlippenbachii subcommunity of the P. densiflora community and the Typical subcommunity of the Q. mongolica community were distributed in similar environments.

• Journal of Korean Society of Forest Science
• /
• v.90 no.3
• /
• pp.249-256
• /
• 2001

The objective of this study was to analyze characters of the vegetation structure, vegetation-environment relationships of Kyeryongsan forest community. Fifty plots were sampled in the valley forest of Donghaksa, Gabsa, Sanghasinri and Shinwonsa regions in Kyeryongsan. Field survey was carried out in August of 1999 to examine a vegetation type and measure a diameter. The classification by TWINSPAN, the DCCA ordination, and structure of stand were used to analyze data. The results of this study are as follows : 1. With the classification by TWINSPAN, the community was categorized into four groups, such as Carpinus laxiflora, Quercus variabilis-Quercus serrata, Zelkova serrata-Celtis jessoensis and Carpinus cordata communities. 2. The dominant species in Carpinus laxiflora community were Carpinus laxiflora, Quercus variabilis, Quercus serrata, Pinus densiflora and Styrax japonica. The dominant species in Quercus variabilis-Quercus serrata community were Quercus variabilis, Quercus serrata, Styrax japonica, Castanea crenata and Platycarya strobilacea. The dominant species in Zelkova serrata-Celtic jessoensis community were Quercus serrata, Castanea crenata, Lindera erythrocarpa, Zelkova serrata and Styrax japonica. The dominant species in Carpinus cordata community were Carpinus cordata, Carpinus laxiflora, Sapium japonicum, Cornus controversa and Zelkova serrata. 3. The results of the correlation between Kyeryongsan valley forest community and environmental factors by DCCA ordination method are as follows; The Carpinus laxiflora community was found in low elevation and steep slope area. The Quercus variabilis-Quercus serrata community was found in low elevation and lower slope area. The Zelkova serrata-Celtis jessoensis community was found in high elevation and lower slope area. The Carpinus cordata community was found in high elevation and midium slope area.

• Korean Journal of Plant Taxonomy
• /
• v.39 no.3
• /
• pp.193-198
• /
• 2009

Chromosome analysis using karyotyping and bicolor FISH were carried out for two Maackia species (M. fauriei and M. amurensis) found in Korea. The somatic metaphase chromosome number was 2n = 2x = 18 in both, and the size of these chromosomes ranged from 3.58 to $5.82{\mu}m$. The chromosome complements consisted of two pairs of metacentric (chromosomes 1 and 7), four pairs of submetacentrics (chromosomes 4, 6, 8 and 9) and three pairs of subtelocentrics (chromosomes 2, 3 and 5) in M. fauriei but, chromosomes 4 (subtelocentric) and 7 (submetacentric) of M. amurensis have different morphology. Using bicolor FISH, a pair of 45S rDNA loci were observed for both M. fauriei and M. amurensis, but the number and site of the 5S rDNA signal were different in the two species. M. fauriei has two pairs of 5S signals on chromosomes 7 and 8 but, M. amurensis has four paris on chromosomes 3, 4, 7 and 7. Hence, the 5S rDNA is a useful FISH for Maackia species.

• Journal of agriculture & life science
• /
• v.46 no.4
• /
• pp.41-55
• /
• 2012

On the basis of vegetation data collected by point-centered quarter method in analysis in Baekdudaegan of Gangwon province in the area of Hyangrobong, Odaesan, Seokbyeongsan, Dutasan, Deokhangsan and Hambaeksan, the study was carried out to classify forest communities and to evaluate the successional trends. The classification method of cluster analysis was used to make various disordered forests into several common groups for 1,004 sample points all together. By clustering the forests in the six study areas were classified into 28 forest communities, which were subjected to aggregate 8 representative forest communities on the count of species composition and species diversity. They were Mesophytic mixed forest community, others deciduous forest community, Quercus mongolica (dominant) community, Q. mongolica (pure) community, Pinus densiflora - Q. mongolica community, P. densiflora community, Betula ermanii community and Q. mongolica - Pinus koraiensis community. The ecological outlook from the result indicated that P. densiflora community and P. densiflora - Q. mongolica community, which were located in Seokbyeongsan, Dutasan and Deokhangsan around 1,000m above the sea level showed lower species diversity index. On the contrary Mesophytic mixed forest community, others deciduous forest community which was located in Hyangrobong, Odaesan and Hambaeksan mostly in protected area and national park around 1,500m above the sea level displayed higher species diversity index. As the composition ratio of Q. mongolica within a certain community was decreased, the species diversity was generally increased, assumed that abundance of Q. mongolica might be negatively associated with species diversity in the national deciduous forest.

• Korean Journal of Environment and Ecology
• /
• v.28 no.2
• /
• pp.197-204
• /
• 2014

The purpose of this study was to investigate the vegetation structure of Daphniphyllum macropodum community in the Yeong-sil and Seong-panack. To do so, 26plots ($(20m{\times}20m)$) were set up and surveyed. Plant communities were classified with 3 groups according to the analysis of classification by TWINSPAN and DCA Ordination; Pinus densiflora-Carpinus laxiflora (I), Carpinus laxiflora-Quercus serrata (II) and Carpinus tschonoskii (III). Daphniphyllum macropodum is appearing in understory and shrub layer of all groups. We found that Daphniphyllum macropodum will be dominated in understory and shrub layer. These results was judeged that these influence is depended on difference of altitude and accompanied species. Accompanied species were lived in similar growth environment to Daphniphyllum macropodum. That species were Styrax japonica, Quercus serrata of understory and Ilex crenata, Taxus cuspidata of shrub layer.

• The Korean Journal of Applied Statistics
• /
• v.17 no.3
• /
• pp.445-457
• /
• 2004

Given class-imbalanced data in two-class classification problem, we often do over-sampling and/or under-sampling of training data to make it balanced. We investigate the validity of such practice. Also we study the effect of such sampling practice on boosting of classification trees. Through experiments on twelve real datasets it is observed that keeping the natural distribution of training data is the best way if you plan to apply boosting methods to class-imbalanced data.

• 한국벤처창업학회:학술대회논문집
• /
• 2021.11a
• /
• pp.185-187
• /
• 2021

관리종목 지정 제도는 상장 기업 내 기업의 부실화를 경고하여 기업에게는 회생 기회를 주고, 투자자들에게는 투자 위험을 경고하기 위한 시장규제 제도이다. 본 연구는 관리종목과 비관리종목의 기업의 재무 데이터를 표본으로 하여 관리종목 지정 예측에 대한 연구를 진행하였다. 분석에 쓰인 분석 방법은 로지스틱 회귀분석, 의사결정나무, 서포트 벡터 머신, 소프트 보팅, 랜덤 포레스트, LightGBM이며 분류 정확도가 82.73%인 LightGBM이 가장 우수한 예측 모형이었으며 분류 정확도가 가장 낮은 예측 모형은 정확도가 71.94%인 의사결정나무였다. 대체적으로 앙상블을 이용한 학습 모형이 단일 학습 모형보다 예측 성능이 높았다.

• Korean Journal of Environment and Ecology
• /
• v.32 no.1
• /
• pp.118-131
• /
• 2018

The forest vegetation of Juwangsan National Park, which is famous for its towering scenic valleys, was syntaxonomically described. The study adopted the $Z{\ddot{u}}rich$-Montpellier School's method emphasizing a matching between species composition and habitat conditions. A combined cover degree and the r-NCD (relative net contribution degree) were used to determine a performance of 265 plant species listed-up in a total of 52 phytosociological $relev{\acute{e}}s$. Nine plant communities were classified through a series of table manipulations, and their distribution and actual homotoneity($H_{act}$) were analyzed. Syntaxa described were Carex gifuensis-Quercus mongolica community, Athyrium yokoscense-Quercus mongolica communiy, Arisaema amurense-Quercus serrata community, Lespedeza maximowiczii var. tomentella-Quercus variabilis community, Tilia rufa-Quercus dentata community, Carex ciliatomarginata-Carpinus laxiflora community, Aristolochia manshuriensis-Zelkova serrata community, Onoclea orientalis-Fraxinus mandshurica community, and Carex humilis var. nana-Pinus densiflora community. A zonal distribution was reviewed and the altitude of about 700 m was the transition zone between the cool-temperate central montane zone (Lindero-Quercenion mongolicae region) and southern submontane zone (Callicarpo-Quercenion serratae region). Only 19 taxa were associated with r-NCD 10% or more, most of which were tree species occurring in the Lindero-Quercenion and some of which was a member of open forests. Species composition of forest vegetation was much less homogeneous, showing the lowest $H_{act}$. Nearly natural forests and/or secondary forests in the Juwangsan National Park were defined as a regional vegetation type, which reflects much stronger continental climate in the Daegu regional bioclimatic subdistrict, rhyolitic tuff predominant, and wildfire interference.

• The Journal of the Korea Contents Association
• /
• v.7 no.8
• /
• pp.13-20
• /
• 2007

Decision tree is one of the most useful analysis methods for various data mining functions, including prediction, classification, etc, from massive data. Decision tree grows by splitting nodes, during which the purity increases. It is needed to stop splitting nodes when the purity does not increase effectively or new leaves does not contain meaningful number of records. Pruning is done if a branch does not show certain level of performance. By pruning, the structure of decision tree is changed and it is implied that the previous splitting of the parent node was not effective. It is also implied that the splitting of the ancestor nodes were not effective and the choices of attributes and criteria in splitting them were not successful. It should be noticed that new attributes or criteria might be selected to split such nodes for better tries. In this paper, we suggest a procedure to modify decision tree by Fuzzy theory and splitting as an integrated approach.

• Korean Journal of Plant Taxonomy
• /
• v.34 no.3
• /
• pp.189-203
• /
• 2004

Numerical analysis based on 33 morphological characters from 25 populations of 8 species of tribe Forsythieae in Korea was conducted to investigate the taxonomic delimitation and discuss the systematic relationships. In this study, Fontanesia phyllyreoides Labill was adopted as comparing outgroup to discuss the taxonomic status of Abeliophyllum distichum and elucidate the taxonomic relationships between tribe Forsythieae and tribe Fontanesiae. Based on the results of PCA, the sum of contributions for the total variance of three major principal components was 79.6% (PC1 54.2%, PC2 15.4% and PC3 10.0%, repectively). Two dimensional plotting from PCA results recognized three distinct generic clusters. Among the populations of Forsythia, two distinct groups were clustered as I. koreana-saxatilis-viridissima and II. ovata-nakaii. However, 15 populations of Abeliophyllum distichum were arranged randomly without any tendency, and the infraspecies of Abeliophyllum distichum could be recognized as individual variations. Fontanesia phyllyreoides Labill was clustered independently and intertribal limitation was clearly distinguished.