• Journal of Korean Society of Forest Science
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• v.103 no.3
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• pp.339-352
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• 2014

The study was carried out to analyze vegetation structure of Pinus densiflora and Quercus mongolica forests located in Jochimryeong to Shinbaeryeong of the Baekdudaegan mountain range. The survey for 50 plots was conducted from April 2012 to August 2013 in the permanent plots ($100m{\times}100m$) using phytosociological analysis. As a result, the vegetations were classified into five vegetation units. In species composition, they were classified into Q. mongolica community group divided into 2 community such as Fraxinus rhynchophylla community and Carpinus cordata community, F. rhynchophylla community was subdivided Pinus densiflor group (into Euonymus sachalinensis subgroup, Vitis coignetiae subgroup) and Juglans mandshurica group. C. cordata community was subdivided Acer komarovii group and Betula ermanii group. In terms of importance value, P. densiflora and Q. mongolica were more than 20% respectively. P. densiflora was found to have the highest relative coverage. Analysis of interspecific association showed four types which were coincident with differential species and character species on the constancy table. Based on the diameter class distribution, P. densiflora forest presented a normal distribution pattern except for other species which showed a reverse Jshaped distribution pattern, therefore P. densiflora forest would likely be replaced by Q. mongolica forests. While in Q. mongolica forest, diameter class distribution of all species population presented a reverse J-shaped distribution pattern, therefore Q. mongolica forest could likely remain in the future.

• Korean Journal of Environment and Ecology
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• v.28 no.5
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• pp.574-587
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• 2014

In this study, vertical distribution patterns of Quercus mongolica Fisch. ex Ledeb. and Q. serrata Murray in Korea were recognized and possibility of introgressive hybridization and gene flow between Q. mongolica and Q. serrata in Mt. Jiri was inferred by flavonoid analyses. The most critical factor on distribution patterns was the altitude in accordance with temperature condition. A zonal distribution was recognized: Quercus mongolica zone in the upper area and Q. serrata zone in the lower area. In Central Korea, the range of vertical distribution of Q. mongolica was above alt. 100m, almost everywhere, whereas that of Q. serrata was from alt. 0 m to alt. 500(-700) m, and the species is rare above that altitude. But in Southern Korea, Q. serrata is found up to above alt. 1,000 m, whereas frequency of Q. mongolica reduces as elevation in decline and the species is rare below alt. 300 m, even though pure stands being formed on higher mountain slope. Altitudinal distribution of the two species, however, overlaps, where the two species occur together. Thirty-seven individuals of Q. mongolica and Q. serrata in Mt. Jiri and other area were examined for leaf flavonoid constituents. Twenty-three flavonoid compounds were isolated and identified; they were glycosylated derivatives of the flavonols kaempferol, quercetin, isorhamnetin, myricetin, and four compounds among the flavonoid compounds were acylated. Kaempferol 3-O-glucoside, quercetin 3-O-glucoside, quercetin 3-O-galactoside and its acylated compounds were major constituents and present in all individuals. Quercus mongolica is distinguished from Q. serrata by the presence of quercetin 3-O-arabinosylglucoside and by high concentration of three acylated compounds, acylated kaempferol 3-O-glucoside, quercetin 3-O-glucoside, quercetin 3-O-galactoside, and by relatively low concentration or lacking of rhamnosyl flavonol compounds. There are intraspecific variations in flavonoid profiles for Q. mongolica and Q. serrata, the flavonoid profiles for individuals of two species in hybrid zone (sympatric zone) tend to be similar to each other, qualitatively and quantitatively. These findings strongly suggest that gene exchange or gene flow occurs through the introgressive hybridization between Q. mongolica and Q. serrata in Mt. Jiri. Therefore, Quercus crispula, occupying morphologically intermediate position between Q. mongolica and Q. serrata, is suspected of being a hybrid taxon of two putative parental species.

• The Korean Journal of Applied Statistics
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• v.14 no.1
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• pp.91-101
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• 2001

It has been shown that the multiple trees predictors are more accurate in reducing test set error than a single tree predictor. There are two ways of generating multiple trees. One is to generate modified training sets by resampling the original training set, and then construct trees. It is known that arcing algorithm is efficient. The other is to perturb randomly the working split at each node from a list of best splits, which is expected to generate reasonably good trees for the original training set. We propose a new combined multiple regression trees predictor which uses the latter multiple regression tree predictor as a predictor based on a modified training set at each stage of arcing. The efficiency of those prediction methods are compared by applying to high throughput screening of chemical compounds for biological effects.

• Korean Journal of Environment and Ecology
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• v.7 no.2
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• pp.155-163
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• 1994

To investigate the structure and the conservation strategy of natural forest at Paekryunsa-Hyangcho kpong area in Tokyusan, 21 plots (400$m^2$) set up with random sampling method. Four groups were classified by cluster analysis. High positive correlations was proved between Tripterygium regelii and Acer tschonoskii var. rubripes, Viburnum sargentii and Betula ermanii, Corylus heterophylla var. thunbergii and Stephanandra incisa, Betula costata and Cornus controversa, Acer mono and Tilia amurensis, Tilia amurensis and Kalopanax pictum, Lonicera maackii and Viburum sargentii, and Betula ermanii, Acer tschonoskii var. rubripes and Taxus cuspidata, and Viburnum sargentii, and High negative correlations was proved between Acer pseudo-sieboldianum and Viburnum sargentii, Tripterygium regelii and Stephanandra incisa, Acer tschonoskii var. rubripes, and Stephanandra incisa. Species diversity(H') of investigated area was calculated 0.9402~1.2473. Taxus cuspidata, Betula ermanii and Abies koreana at Hyangchokpong area in Tokyusan should be conserved.

• Korean Journal of Plant Taxonomy
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• v.35 no.4
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• pp.247-272
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• 2005

The Philadelphus schrenkii complex including P. schrenkii var. schrenkii, P. schrenkii var. jackii, P. schrenkii var. mandshuricus, P. tenuifolius, P. pekinensis, P. seoulensis, P. lasiogynus, and P. scaber, is distributed in China, Korea, japan, and far eastern Russia. Their taxonomic delimitations are obscure because quantitative characters, such as presence/absence and density of hair on leaf, petiole, style, disc, calyx-tube, and pedicel, are highly variable with no apparent characteristics that consistently distinguish from each other within the group. Thus, these morphological characters are reexamined using univariate analyses. P. pekinenesis is distinct from other taxa in having glabrous disk, calyx, pedicel, and leaf blade. In addition, the number of flowers in an inflorescence [(5)7-9(11) vs 5-7 in other taxa], smaller calyx tube [2.5-3 mm vs. (2.5)3-4(5.9) in other taxa], and slightly divided styles help distinguish P. pekinenesis from other related taxa in Korea. However, P. schrenkii var. schrenkii, P. schrenkii var. jackii, P. schrenkii var. mandshuricus, and P. lasiogynus show continuous variation in the pubescence of disk, calyx, pedicel, and leaf blade, and this may reflect a lack of divergence among them. Particular emphases are placed on P. tenuifolius and P. seoulensis, because of the high degree of morphological intergradation with respect to the degree of pubescence in disk, calyx, pedicel, and leaf blade and their inconsistent circumscription across various systematic treatments. P. scaber, distributed in the southern Korea, has often been treated as an independent species having exfoliated branchlets, distinct serrated leaf margin, and recurved styles. However, this current study suggests that P. scaber should be recognized as a form of P. tenuifolius because these distinguishing characters are continuous between P. tenuifolius and P. scaber. In geographical distribution, P. pekinensis is mainly distributed in the southern part of Korea, while P. tenuifoilus and P. schrenkii are commonly found all over the country.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.38-38
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• 2011

일반적으로 레일마모는 열차의 주행안전 및 승차감에 미치는 영향이 크고, 소음 진동의 주요원인으로 작용한다. 또한 레일마모가 발생할 경우 궤도구조의 파괴를 촉진시킴으로써 차량 및 궤도유지보수비를 크게 증가시킨다. 따라서 구간 특성 및 환경 영향 인자 등 현장에서 발생하는 마모 원인을 체계적으로 분석함으로써 마모를 저감할 수 있도록 차량운행 조건과 선로선형 및 궤도구조를 설계하는 것은 중요한 과제이다. CART(Classification And Regression Tree; 분류와 회귀나무) 분석은 패키지화된 좋은 분류 및 예측도구 기법으로 나무의 상위 분리수준에서 일반적으로 나타나는 가장 중요한 입력변수들을 사용하는 등의 입력변수를 선정하는 경우 매우 유용하다. 본 연구에서는 다변수 구간특성 및 환경인자를 고려한 검측 자료 상관관계 분석을 위한 회귀 나무기반 모델(TBM: Tree Based Model) 분석 수행을 위해 지하철 2호선 마모 데이터와 마모 데이터에 영향을 미치는 각종 다변수 구간특성 및 환경인자를 사용하였다. 2호선 지하철의 구간특성 인자 및 환경인자는 레일의 종류, 레일의 위치, 도상, 곡률반경, 캔트 슬랙 및 운행 일수 등으로 구분하였다. 레일의 종류는 ks-50kg과 ks-60kg 두 종류의 레일이 있으며, 레일의 위치는 지상과 지하로 크게 구분할 수 있다. 도상은 콘크리트 도상, 자갈 도상과 일부 구간의 방진상 콘크리트 도상으로 구분할 수 있으며, 곡률반경은 직선구간과 완화곡선 구간 및 최소 250m부터 627m까지 분포된 원 곡선 구간으로 구분할 수 있다. 캔트 간격은 최소 96cm 부터 120cm 간격으로 구분하며, 슬랙은 5~9cm에 분포하고, 운행 기간은 해당 기간 동안 유지보수 이력이 없는 구간을 선정하여 2005년부터 2006년까지 4번에 걸쳐 검측된 지하철 2호선 내선 마모데이터를 사용하였다. 총 X1부터 X7까지 총 7개의 구간특성 또는 환경특성을 영향인자로 선정하였으며, 이러한 영향인자에 의해 결정되는 종속 인자로 Y1인 직마모와 Y2인 측마모를 선정하여 이 중 실질적으로 지하철 궤도의 성능 평가에 주요 판단인자로 사용되는 측마모와 구간특성 및 환경영향인자와의 상관관계 분석을 수행하였다. 해당 마모 데이터가 검측되는 기간 동안 유지보수 이력이 없는 12272 point의 데이터를 검출하였고 CART 프로그램을 이용하여 데이터를 분석하였으며, CART 프로그램의 해석을 위해 종속변수인 직마모량은 각 검측 지점의 마모량에 해당하는 등급으로 변환하여 분석을 수행하였다. 레일의 마모에 영향을 미치는 구간특성 및 환경인자와 종속 변수로 사용된 레일의 마모량 사이의 CART를 이용한 상관관계 분석은 실제 구조물에서 영향인자간의 상관 관계와 유사하며, 추후 연구에서는 이를 바탕으로 하여 정량화된 검측 데이터를 종속변수로 하여 구간특성 또는 환경인자 등 외부 영향인자를 고려한 궤도 검측데이터와의 상관관계 분석을 수행할 계획이다.

• Journal of the Korean Data and Information Science Society
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• v.21 no.5
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• pp.917-926
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• 2010

It is known that bagging and boosting techniques improve the performance in classification problem. A number of researchers have proved the high performance of bagging and boosting through experiments for categorical response but not for continuous response. We study whether bagging and boosting improve data mining methods for continuous responses such as linear regression, decision tree, neural network through bagging and boosting. The analysis of eight real data sets prove the high performance of bagging and boosting empirically.

• Korean Journal of Environment and Ecology
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• v.7 no.2
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• pp.172-180
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• 1994

The forest of Choksangsansong area was studied to investigate vegetational structure with twenty-five plots(20m$\times$25m). Relative importance values, DBH class distribution, species, diversity indices, DCA ordination and TWINSPAN classification were used for vegetational structure analysis. Quercus mongolica, Carpinus cordata, Quercus serrata and Cornus controversa were appeared to be dominant species in each plot and dominant species in the Choksangsansong area was Quercus mongolica. The forest of Choksangsansong area was classified into four groups and showed seral stage from Quercus mongolica to Carpinus cordata. Vegetational succession in the Choksangsansong area shall be accelerated to moist and shade tolerant species due to cool and humid climatic condition by upper dam construction of the Mujuyangspalchonso (pumping up power station).

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.1
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• pp.11-21
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• 2014

The purpose of this study was to furnish basic information for forest community ecology and to accumulate vegetational datum related to hierarchy of forest community for the efficient management of forest vegetation in Mt. Mani. Samples were collected and analyzed by 32 releves from August to October in 2010 using phytosociological analysis methodology of Z-M school and importance value analysis. The results were summarized that the forest vegetation was classified into 5 units in total. Importance value at vegetation unit 1 indicated Pinus densiflora 54.31 (18.10%), Quercus mongolica 39.21 (13.07%), Carpinus coreana 37.29 (12.43%), at vegetation unit 2 Quercus mongolica 89.43 (22.23%), Rhododendron mucronulatum 57.75 (14.43%), Carpinus coreana 47.19(11.80%), at vegetation unit 3 Styrax japonica 53.97 (13.50%), Acer mono 33.60 (8.40%), Carpinus coreana 26.48 (6.62%), Quercus serrata 22.51 (5.64%), at vegetation unit 4 Carpinus coreana 47.70 (11.92%), Quercus acutissima 38.40 (9.60%) and at vegetation unit 5 Evodia daniellii 80.59 (20.14%), Robinia pseudoacacia 35.00 (8.74%), Pueraria thunbergiana 28.63 (7.15%), Quercus dentata 28.20 (7.05%) in the order, respectively.

• Journal of Korean Society of Forest Science
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• v.80 no.4
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• pp.360-368
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• 1991

Utilizing chi-square test statistics, inter-species association and covariation were analyzed for the 37 woody plant species in a deciduous forest dominated by Quercus mongolica and Q. variabilis. within 50 temporarily established $20m{\times}20m$ square quadrats, the association for each pair of species was presented based on the presence-absence parameters. Acer palmatum had significant positive association with Acer mono and Kalopanax pictus, but negative association with Pinus densiflora. Other positively associated species pairs were Prunus sargentii-Macckia amurensis, Quercus serrata-Kalopanax pictus, Symplocos chinensis var. pilosa-Euonymus oxyphyllus, and Ulmus davidiana var. japonica-Lindera obtusiloba. The covariation far each pair of species was evaluated based on the quantitative measures, density and basal area. Overall results showed that the association and covariation values among species generally agreed with each other. Because covariation was calculated by density and basal area of the tallied species in the sample plots, the number of species pairs of covariation tended to be greater than those of association. Especially, Pinus densiflora, considered to be pioneer species in the successional stage, had negative covariation with most of climax species. These ecological information could be applied to silvicultural practices, such as ecosystem classification, establishment of mixed hardwood forest, and tending operations for marking crop trees and desirable species.