• Journal of Environmental Science International
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• v.26 no.10
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• pp.1147-1153
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• 2017

To maintain a rich biological diversity is important to develop for biomaterial resources such as Korean evergreen broad-leaved tree species, the distribution of which is restricted to the southern part of Korean peninsula. We assessed photosynthetic characteristics of Quercus acuta and Castanopsis sieboldii, the representative evergreen broad-leaved trees in Korea, in order to establish a basis for conservation strategy related to distributional change in evergreen broad-leaved tree species according to climate change. Photosynthetic characteristics were evaluated in the sun and shade leaves of the two species. Sun leaves in both species revealed higher light compensation point and maximum photosynthetic rate compared to the shade leaves. In addition, photosynthetic rate was higher in Q. acuta than C. sieboldii, which was supported by a higher leaf nitrogen content and leaf mass per area. Water use efficiency was also higher in Q. acuta as compared to that in C. sieboldii. Similar photosynthetic rate, however, was shown in photosynthetic response to $CO_2$ concentration in the intercellular space. These results suggest that both species could respond differently to the changing environmental factors including climate change, suggesting the possibility of distributional changes resulting from a differential growth rate.

• Journal of applied mathematics & informatics
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• v.37 no.3_4
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• pp.163-176
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• 2019

Given a distribution of pebbles on the vertices of a connected graph G, a pebbling move is defined as the removal of two pebbles from some vertex and the placement of one of those pebbles at an adjacent vertex. The t-pebbling number, $f_t(G)$, of a connected graph G, is the smallest positive integer such that from every placement of $f_t(G)$ pebbles, t pebbles can be moved to any specified vertex by a sequence of pebbling moves. A graph G has the 2t-pebbling property if for any distribution with more than $2f_t(G)$ - q pebbles, where q is the number of vertices with at least one pebble, it is possible, using the sequence of pebbling moves, to put 2t pebbles on any vertex. In this paper, we determine the t-pebbling number for the middle graph of a complete binary tree $M(B_h)$ and we show that the middle graph of a complete binary tree $M(B_h)$ satisfies the 2t-pebbling property.

• Journal of Korean Society of Forest Science
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• v.87 no.4
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• pp.631-641
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• 1998

The objectives of this study were 1) to classify the types of Quercus mongolica stands at Mt. Joongwang and compare their quality, and 2) to determine the proper future tree number of Q. mongolica per ha and the appropriate distance between the future trees. The results from this study were as follows : Q. mongolica stands at Mt. Joongwang was classified into four types, pure Q. mongolica stand as stand type I, Q. mongolica - hardwood stand as stand type II, Q. mongolica - Pines densiflora stand as stand type III, Hardwood - Q. mongolica stand as stand type IV, according to mixture rate in stand volume. Stand type IV showed the best quality stem of Q. mongolica among the stand types, and the stem quality of Q. mongolica in Q. mongolica stand mixed with hardwood as stand types II and IV was better than those in pure Q. mongolica stand as stand type I and in Q. mongolica - P. densiflora stand as stand type III. If the management goal for Q. mongolica stand is to produce its high quality-timber, it is desirable to sustain proper mixture rate of Q. mongolica with another hardwoods. The proper number of future trees in pure Q. mongolica stand as stand type I was 122trees/ha and reasonable distance between the future trees was 9.15m. The distance between future trees in other stand types was 7.2m to 9.3m for stand types II and IV, while 8.0m for stand type III. Thus, the classification of Q. mongolica stand type based on stand character and maturity, and proper stem number of future tree and optimum distance between future trees would be a useful forest tending work.

• Journal of Korean Society of Forest Science
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• v.89 no.1
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• pp.18-23
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• 2000

Leaves of various, 3 to 5-year-old Quercus hybrids were intermediate in size between their parental species. The petiole length was the smallest in the hybrids of Q. dentata ${\times}$ Q. crispula $F_1$ and was intermediate in the hybrids of Q. aliena ${\times}$ Q. serrata $F_1$ and Q. dentata ${\times}$ Q. aliena $F_1$ between their parents. The number of serration in hybrids was close to their mother tree's in most of crossing combinations. The serration depth and the ratio between longitudinal and transverse length of leaves were intermediate between the values of their parental species.

• Journal of applied mathematics & informatics
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• v.16 no.1_2
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• pp.115-123
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• 2004

A recursive tree is constructed by starting with a root node and repeatedly adjoining new nodes to one node of the tree already constructed. Such a tree can represent, for example, the heirarchy of a workforce of a company that grows via recruiting. At times of economic depression, the company may decide to layoff participants, and in some cases it is a fair policy to relieve the last senior worker (most recent entry in the tree). If we remove an edge from such a tree then it falls into two subtrees one of which contains the most recent entry. If we continue to remove edges from the successively smaller subtrees that contain the most recent entry, we eventually isolate the most recent entry. We consider how many randomly selected edges must be removed in average before isolating the most recent entry by this procedure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.12
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• pp.1055-1059
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• 1998

The correlation between the propagation of electrical tree and distributions of partial discharge(PD) pulses accompanying with electrical tree of bush type in low density polyethylene were discussed. We measured the growth of electrical tree by using optical microscope and PD data simultaneously. The PD data detected and analyzed were PD magnitude, repetition rate, average discharge power, average phase angle, and $\psi$-q-n distribution pattern. The average discharge power and repetition rate of PD had good linear relation with area of tree. Repetition rate and peak discharge magnitude and width of discharge phase angle increased with the tree.

• The Transactions of the Korea Information Processing Society
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• v.7 no.5
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• pp.1370-1376
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• 2000

Consider the problem to updata breadth-First Spanning Tree in response to topology change of the network. The paper proposes an efficient distributed algorithm that solves such a problem after several processors and links are added and deleted. Its message complexity and its ideal-time complexity are O(p√q+q+a+n') respectively, where n' is the number fo processors in the network after the topology change, a is the number of added links, p is the total number of links in the biconnected component (of the network before the topology change) including the detected links or added links, and q is the total number of processors in the biconnected component (of the network before the topology change) including the deleted links or added links, and q is the total number of processors in the biconnected component including the deleted links or added links.

• Mycobiology
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• v.49 no.4
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• pp.385-395
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• 2021

Fungal endophytes have been recorded in various plant species with a richness of diversity, and their presence plays an essential role in host plant protection against biotic and abiotic stresses. This study applied the Illumina MiSeq sequencing platform based on the amplification of fungal ribosomal ITS2 region to analyze fungal endophytic communities of two oak species (Quercus mongolica and Q. serrata) with different oak wilt disease susceptibilities in Korea. The results showed a total of 230,768 sequencing reads were obtained and clustered at a 97% similarity threshold into 709 operational taxonomic units (OTUs). The OTUs of Q. serrata were higher than that of Q. mongolica with the number of 617 OTUs and 512 OTUs, respectively. Shannon index also showed that Q. serrata had a significantly higher level of fungal diversity than Q. mongolica. Total of OTUs were assigned into 5 fungal phyla, 17 classes, 60 orders, 133 families, 195 genera, and 280 species. Ascomycota was the dominant phylum with 75.11% relative abundance, followed by Basidiomycota with 5.28%. Leptosillia, Aureobasidium and Acanthostigma were the most abundant genera detected in Q. serrata with the average relative abundance of 2.85, 2.76, and 2.19%, respectively. On the other hand, Peltaster, Cladosporium and Monochaetia were the most common genera detected in Q. mongolica with the average relative abundance of 4.83, 3.03, and 2.87%, respectively. Our results indicated that fungal endophytic communities were significantly different between two oak species and these differences could influence responses of host trees to oak wilt disease caused by Raffaelea quercus-mongolicae.

• Journal of Forest and Environmental Science
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• v.20 no.1
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• pp.40-50
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• 2004

This study was conducted to provide appropriate tending operation strategies for the natural deciduous forest, by the method of evaluating the stand quality, suggesting the removal plan for the undesirable trees, and predicting improvement cutting practice by tree quality evaluation. The results showed that average number of trees per ha was 717 stems, average DBH was 21.1cm. and average height was 13.6m. Canopy dominant species were in the order of Quercus serrata, Q. variabilis, Q. mongolica, Styrax obassia, and Ulmus davidiana var. japonica. Based on grades of four tree form factors for all tree in the study plots, we estimate the change of tree numbers. DBH and height with the improvement cutting by different tree grade. When the higher tree grade was applied to tending operation, the number of stem was decreased, but the values of DBH and height were not changed much, predicted to improve the stand quality.

• Journal of Plant Biology
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• v.33 no.3
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• pp.173-182
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• 1990

To investigate the structure of the plant community structure of Mt. Yongmun in Kyonggi-do, fifty-four plots were set up by the clumped sampling method. The classification by TWINSPAN and DCA ordination were applied to the study area in order to classify them into several groups based on woody plant and environmental variables. By both techniques, the plant community were divided into two groups by the aspect. the dominant species of south aspect were Pinus densiflora, Quercus aliena, Q. mongolica, Carpinus laxiflora and of north aspect were Q. ongolica, Fraxinus rhynchophylla. The successional trends of tree species in south aspect seem to be from P. densiflora through Q. serrata, Q. aliena, A. mongolica to C. laxiflora. As a result of the analysis for the relationship between the stand scores of DCA and environmental variables, they had a tendency to increase significantly from the P. densiflora and Q. mongolica community to C. laxiflora and F. rhynchophylla community that was the soil moisture, the amount of soil humus and soil pH.