• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.2
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• pp.49-67
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• 2020

This study was conducted to compare and analyze forest vegetation distributed in Geumosanseong-inside in Geumosan Provincial Park from 2017.10 to 2019.6. The vegetation structure was classified by the phytosociological method and TWINSPAN and the correlation between the community structure and the environmental factors was analyzed using DCCA ordination analydsis. The vegetation structures are Quercus mongolica, Fraxinus mandshurica, Q. acutissima, Larix leptolepis, Prunus padus and Morus alba community by the phytosociological method and 16 communities under TWINSPAN. The importance value of Q. mongolica(64.5) was the highest, and followed by F. mandshurica, L. leptolepis, Acer pseudosieboldianum, M. alba, P. padus, Q. acutissima, Sorbus alnifolia, P. serrulata var. pubescens, F. sieboldiana, Rhododendron schlippenbachii and Castanea crenata which is consistent with species having the dominance status by analysis of the vegetation structure. As the results of DBH analysis for taxon with high importance values, Q. mongolica and M. alba represented normal distribution, and thus, the dominance status of these species is likely to continue. L. leptolepis will maintain the dominance status due to high density of large individuals as compared with species above medium size. However, it will decrease because of high mortality after increase in age class. F. mandshurica and P. padus continue to show dominance status due to high density of young individuals as compared with species above medium size. Q. acutissima have high density of individuals above intermediate size and low density of young individuals, and thus, will maintain the dominance status. A. pseudosieboldianum, F. sieboldiana and R.schlippenbachii which are arborescent will present continuously high dominance status because of high density of young individuals. Soil analysis shows that whereas pH, Ca²⁺ and Mg²⁺ in the research area were lower than the average values of overall forest soil and O.M, T-N, C.E.C and P₂O₅ were higher. We expected that these results were due to agricultures until 50 years ago in Geumosanseong-inside. As a result of DCCA ordination analysis using eleven environmental factors and communities classified by the phytosociological method analysis showed that Q. mongolica was distributed in the environment with higher elevation and O.M and steep slope, and lower P₂O₅, Mg²⁺ and Ca²⁺. In contrast to F. mandshurica, Q. acutissima was distributed in higher K⁺ and lower pH. L. leptolepsis was distributed in various environment.

• Journal of Korean Society of Forest Science
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• v.98 no.2
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• pp.183-188
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• 2009

It is necessary to determine the amount of carbon dioxide ($CO_2$) absorbed by plants and released from forest floor into atmosphere, to gain a better understanding how forests participate in the global carbon cycle. Soil $CO_2$ efflux, litter production, and decomposition were investigated in Q. variabilis and P. densiflora stands in the vicinity of Gwangju, Chonnam province. Soil $CO_2$ efflux was measured using Infrared Gas Analyzer (IRGA) at midday of the 10th day at every month over 12-month period, to quantify seasonal and annual budgets of soil $CO_2$ efflux. Soil temperature and soil moisture were measured at the same time. Seasonal soil $CO_2$ efflux in Q. variabilis and P. densiflora were the highest in summer season. In August, maximum soil $CO_2$ efflux in Q. variabilis and P. densiflora was 7.49, $4.61CO_2{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, respectively. Annual $CO_2$ efflux in each stand was 1.77, $1.67CO_2kg{\cdot}m^{-2}$ respectively. Soil $CO_2$ efflux increased exponentially with soil temperature and related strongly in Q. variabilis ($r^2$=0.96), and in P. densiflora ($r^2$=0.91). Litter production continued throughout the year, but showed a peak on November and December. Annual litter production in the Q. variabilis and P. densiflora stands were $613.7gdw{\cdot}m^{-2}{\cdot}yr^{-1}$ and $550.5gdw{\cdot}m^{-2}{\cdot}yr^{-1}$.$yr^{-1}$, respectively. After 1 year, % remaining mass of Q. variabilis and P. densiflora litter was 48.2, 57.1%, respectively. The soil $CO_2$ efflux rates in this study showed clear seasonal variations. In addition, the temporal variation in the $CO_2$ efflux rates was closely related to the soil temperature fluctuation rather than to variations in the soil moisture content. The range of fluctuation of soil $CO_2$ efflux and litter decomposition rate showed similar seasonal changes. The range of fluctuation of soil $CO_2$ efflux and litter decomposition rate was higher during summer and autumn than spring and winter.

• Journal of the Korean Applied Science and Technology
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• v.33 no.1
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• pp.41-50
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• 2016

In this study, the extracts from the leaves of Rhaphiolepis indica(R. indica) and Quercus salicina(Q. salicina) confirmed antioxidative effects. The antioxidative and cytotoxic effects of the two extracts were analyzed according to varied concentrations and time. The extracts of R. indica and Q. salicina showed dose-dependent DPPH radical scavenging activities. The extracts of R. indica and Q. salicina at concentrations of 5 mg/mL showed DPPH radical scavenging activities at 89.93 and 92.41%. Therefore, Q. salicina were confirmed to have higher antioxidative effects than R. indica. Total phenolic contents were 65.20 mg GAE/g for R. indica and 85.20 mg GAE/g for Q. salicina. The result that Q. salicina have higher total phenolic contents than R. indica suggested a correlation between total phenolic contents and DPPH radical scavenging activity. The cell protective effects of HepG2 and A549 cells under oxidative stress, both the extracts showed relatively low cell protective effects at around 10%. The Cytotoxic effects of A549 Cells did not show cytotoxicity at concentrations of $100{\mu}g/mL$ or below. The results of this study are likely to be used as basic data to develop antioxidants using the extract of R. indica and Q. salicina.

• Honam Mathematical Journal
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• v.39 no.3
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• pp.379-399
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• 2017

The objective of this research article is to establish two relationships between q-product identities, theta function identities and combinatorial partition identities, using elementary results.

• Journal of applied mathematics & informatics
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• v.31 no.3_4
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• pp.343-352
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• 2013

In this paper, we give a formula of $(P+Q)^D$ under the conditions $P^2Q+QPQ=0$ and $P^3Q=0$. Then applying it to give some results of block matrix $M=(^A_C^B_D)$ (A and D are square matrices) with generalized Schur complement is zero under some conditions. Finally, numerical examples are given to illustrate our results.

• Korean Journal of Mathematics
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• v.25 no.2
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• pp.201-209
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• 2017

There exists already mass formula which is the number of self orthogonal codes in $GF(q)^n$, but not proof of it. In this paper we described some theories about finite geometry and by using them proved the mass formula when $q=p^m$, p is odd prime.

• Korean Journal of Mathematics
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• v.16 no.3
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• pp.309-322
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• 2008

We prove the existence of infinitely many solutions of the nonlinear higher order elliptic equation with Dirichlet boundary condition $(-{\Delta})^mu=q(x,u)$ in ${\Omega}$, where $m{\geq}1$ is an integer and ${\Omega}{\subset}{R^n}$ is a bounded domain with smooth boundary, when q(x,u) satisfies some conditions.

• The Pure and Applied Mathematics
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• v.23 no.4
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• pp.377-383
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• 2016

The set of priors in the representation of coherent risk measure is expressed in terms of quantile function and increasing concave function. We show that the set of prior, $\mathcal{Q}_c$ in (1.2) is equal to the set of $\mathcal{Q}_m$ in (1.6), as maximal representing set $\mathcal{Q}_{max}$ defined in (1.7).

• Proceedings of the Korean Vacuum Society Conference
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• 2007.08a
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• pp.383-383
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• 2007

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.708-710
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• 2018

강화학습은 게임의 인공지능을 대체할 수 있는 수단이지만 불완전한 게임에서 학습하기 힘들다. 학습하기 복잡한 불완전안 카드게임에서 휴리스틱한 전략을 만들고 비슷한 상태끼리 묶으면서 학습의 복잡성을 낮추었다. 인공신경망 없이 Q-러닝만으로 게임을 5만판을 통해서 상태에 따른 전략을 학습하였다. 그 결과 동일한 전략만을 사용하는 대결보다 승률이 높게 나왔고, 다양한 상태에서 다른 전략을 선택하는 것을 관찰하였다.