• Journal of Korean Society of Forest Science
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• v.94 no.6
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• pp.410-419
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• 2005

Community structure of evergreen broad-leaved forest of Mt. Yeogwi in Jin-do was investigated to secure sustainable conservation of evergreen broad-leaved forest. Twenty survey plots of $20m{\times}20m$ were established along the elevation from 200 m to 390 m above the sea level in the northwestern slope. The woody species were tallied at each plots. DBH distribution of the major evergreen broad-leaved trees was investigated to find out the spatial distribution. Cluster analysis was applied to a set of vegetation data, that is, importance value to classify the forest community. Species diversity, evenness and species correlation were analysed. Canonical correspondence analysis was also applied to vegetation data and soil environmental data. Cluster analysis showed that the forests of Mt. Yeogwi were classified into 2 community groups, such as Camellia japonica community group and Quercus acuta community group. C japonica community group was subdivided into C japonica- evergreen broad-leaved trees community, C. japonica-Neolitsea sericea community, and C. japonica-deciduous broad-leaved trees community. Q. acuta community group was subdivided into Q. acuta-C. japonica community, and Q. acuta community. C. japonica, Q. acuta, N. sericea, Machilus thunbergii and Illicium religiosum were dominant evergreen broad-leaved tree species, while Styrax japonica, Lindera erythrocarpa, Cornus kousa, Prunus sargentii, Albizzia julibrisin and Quercus acutissima were major deciduous tree species. Species diversity was greater in Q. acuta community group (0.8231 for Q. acuta-C. japonica community, and 0.8135 for Q. acuta community) than in C. japonica community group (0.7674 for C. japonica-evergreen broad-leaved trees community, 0.6164 for C. japonica-N. sericea community, and 0.7931 for C. japonica-deciduous broad-leaved trees community). DBH 2 cm~10 cm of major evergreen broad-leaved trees occupied 80% of all. C. japonica of less than DBH 5 cm tended to aggregate but distribute randomly or regularly with increasing DBH. Q. acuta distributed more aggregately than C. japonica and Machilus thunbergii for more than 15 cm of DBH. C. japonica correlated negatively with Q. acuta, I. religiosum and C. kousa, but positively with N. sericea. with significance at 1% level. Q. acuta correlated negatively with C. japonica, N. sericea and M. thunbergii but positively with l. religiosum. There were also negative correlation between N. sericea and C. kousa. CCA showed that forest communities were correlated with soil variables such as CEC, soil organic matter and soil pH. With increased soil organic matter and CEC, and decreased soil pH, C. japonica was dominant and forest community and Q. acuta and N. sericea tended to develop in the evergreen broad-leaved forest.

• Korean Journal of Environment and Ecology
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• v.30 no.5
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• pp.829-836
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• 2016

This study was carried out on Kongju National University and its neighboring area, Mt. Gyeryong national park and Mt. Worak national park in the breeding season of long-tailed tits Aegithalos caudaatus from 2008 to 2012. The result of the inquiry, the nests were found in 15 species of trees, and this result shows me it's not choosy about them. But after having classified them according to the features and analyzed them, long-tailed tits preferred evergreen needleleaf tree and deciduous broad-leaf tree and deciduous bush, especially evergreen needleleaf tree. The concealment rate of long-tailed tits' nests was $11.61{\pm}4.79%]\;4.38{\pm}2.19%$(n=29) in Kongju National University and it's neighboring area, $6.06{\pm}2.31%$(n=43) in Mt. Gyeryong national park and $4.38{\pm}2.19%$(n=32) in Mt. Worak national park. By regional groups, the concealment rates of neighboring nests were almost same, but there are no differences among the areas. The average of the color codes was $26.52{\pm}16.14$(n=32) that those of the nest subtract from those of surroundings of the nest. The nests were procryptic according to their surroundings, and if their nest in a tree were evergreen needleleaf trees, they were made of moss. while if the trees of nest in a tree were yellow because of fungus, made of dried moss, they were yellow, too.

• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.356-364
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• 2009

In 2006 and 2007, there was a big outbreak of the Ussur Brown Katydid, Paratlanticus ussurriensis in the central part of Korea attacking some orchard trees. Until 2000, the katydid had not been regarded as an agricultural pest because they were distributed widely in Korea with low population density and their habitats were confined mainly to hillsides of forested areas. The fact that katydid attacked orchard trees with a higher population density seemed to be related to a change in feeding environment. And the shift of their habitats from oak woodlands to commercial orchards was thought to be related to the nutritional contents of their feed. In an attempt to understand these relationships, we conducted an ecological study of the affected areas. When the katydids changed their habitats in early May of 2008 and 2009, they shifted their host plants from oak trees to peach trees. The habitat shift was closely related to the nitrogen (N) content of the host plant leaves. When katydid moved to the hillside adjacent to orchard farm, N content of oak tree leaves decreased dramatically from 5.3% to 2.2%. At that time N content of peach tree leaves were higher than the 2.2% of oak leaves, showing 3.5~5.0%. This range of N content of peach tree leaves has been consistent until late June. And feed preference analysis carried out in the laboratory showed that katydid prefered peach tree leaves to peach fruit to oak tree leaves.

• Journal of Ecology and Environment
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• v.37 no.1
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• pp.21-29
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• 2014

Robinia pseudoacacia has become invasively naturalized in Japan. We investigated the role of sexual reproduction in the development of R. pseudoacacia riparian forests along the Chikumagawa River in Japan, by using five chloroplast (cpSSR) and seven nuclear (nSSR) markers. We identified eight chloroplast haplotypes and 147 nuclear genotypes from 619 R. pseudoacacia trees sampled in three plots (Plots A, B, and C) and along two line transects (Lines D and E). CpSSR analyses showed that multiple maternal lines were distributed along the river, and that some haplotypes from different populations overlapped. In addition, while Plots A and B were separated by a short distance, only these two plots exhibited genetic differentiation in the haplotypes. In the nSSR analysis, all pairwise $F_{ST}$ values among the three plots were significantly different from zero. Kinship analysis based on nSSR markers revealed that kinship connected many individuals to another individual from the same plot. These results indicate that seed dispersal near to mother trees contributes to the fine-scale genetic structure of R. pseudoacacia riparian forests. Our results indicate that sexual reproduction, in addition to asexual reproduction, is a major contributor to the fine-scale formation of R. pseudoacacia forests.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.30 no.2
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• pp.28-36
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• 2012

Forests are one of the basic assets nearest our daily lives that provide the foundation of life necessities, culture and even survival. These assets pervade local residents' lives as culture and the necessities of life, and they will be handed down to posterity. Therefore, this study was conducted to carry out a field survey on old trees, plant communities and forests in the southern coastal areas in Korea, where not many surveys were not conducted on the forest cultural assets, further examining a possibility that some of the trees should be designated as law-protected. As for the survey of plants, this study investigated 80 different spots of old trees, plant communities and forests, located in 11 cities and counties in Gyengnam Province and Jeonnam Province adjacent to the southern coast of Korea. To measure the health and actual maintenance conditions of old trees and plant communities objectively, the standard of judgment was established through the brain storming of experts. As a result of the field survey, out of all the old trees and plant communities that are not law-protected, this study selected old trees and plant communities that are in good health and likely to pass the standard of designating law-protected trees according to the Established Rule 574 of the Korea Forest Service Regulation. As for the plant community and old trees likely to be law-protected, this study judged that the torreya forest in Naneum Li, Namhae and old trees in 13 spots, in cluding so-called 'Couple Pine Tree' in Pyeongsa Li, Hadong, have a high possibility of being designated as a law-protected plant community and old trees. As for the species of old trees, there were 3 zelkova serrata trees, 3 celtis sinensis persoon trees, 2 pinus densiflora trees, 1 castanopsis cuspidata tree, 1 salix chaenomeloides tree and 1 machilus thunbergii tree found in the survey areas. Overall, this study judged that those old trees and plant communities require a national systematic maintenance by being designated as law-protected ones, and their values should be handed down to posterity as our forest cultural assets.

• Asian Journal of Atmospheric Environment
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• v.11 no.1
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• pp.29-32
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• 2017

Ozone concentration in Tokyo Metropolitan area is one of the most serious issues of the local air quality. Tropospheric ozone is formed by radical reaction including volatile organic compound (VOC) and nitrogen oxides ($NO_x$). Reduction of the emission of reactive VOC is a key to reducing ozone concentrations. VOC is emitted from anthropogenic sources and also from vegetation (biogenic VOC or BVOC). BVOC also forms ozone through $NO_x$ and radical reactions. Especially, in urban area, the BVOC is emitted into the atmosphere with high $NO_x$ concentration. Therefore, trees bordering streets and green spaces in urban area may contribute to tropospheric ozone. On the other hand, not all trees emit BVOC which will produce ozone locally. In this study, BVOC emissions have been investigated (terpenoids: isoprene, monoterpenes, sesquiterpenes) for 29 tree species. Eleven in the 29 species were tree species that did not emit BVOCs. Three in 12 cultivars for future planting (25 %) were found to emit no terpenoid BVOCs. Eight in 17 commonly planted trees (47%) were found to emit no terpenoid BVOC. Lower-emitting species have many advantages for urban planting. Therefore, further investigation is required to find the species which do not emit terpenoid BVOC. Emission of reactive BVOC should be added into guideline for the urban planting to prevent the creation of sources of ozone. It is desirable that species with no reactive BVOC emission are planted along urban streets and green areas in urban areas, such as Tokyo.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.9_10
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• pp.476-484
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• 2008

Most string problems and their solutions are relevant to diverse applications such as pattern matching, data compression, recently bioinformatics, and so on. However, there have been few works on the relations between string problems and cryptographic problems. In this paper, we consider the following string reconstruction problems and show how these problems can be applied to cryptography. Given a string x of length n over a constant-sized alphabet ${\sum}$ and a set W of strings of lengths at most an integer $k({\leq}n)$, the first problem is to find the sequence of strings in W that reconstruct x by the minimum number of concatenations. We propose an O(kn+L)-time algorithm for this problem, where L is the sum of all lengths of strings in a given set, using suffix trees and a shortest path algorithm for directed acyclic graphs. The other is a dynamic version of the first problem and we propose an $O(k^3n+L)$-time algorithm. Finally, we show that exponentiation problems that arise in cryptography can be successfully reduced to these problems and propose a new solution for exponentiation.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.2
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• pp.136-141
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• 2013

Lowering tree height has been a key practice for efficient management of persimmon orchards. This experiment was conducted to assess whether fertilization rates could be reduced after lowering the tree height by heavy pruning. Twelve-year-old 'Uenishiwase' persimmon trees were lowered to 2 m from over 3 m by severe dormant pruning, and then conventional fertilization rate was applied to some trees in April (N 224 g, $P_2O_5$ 172 g, and $K_2O$ 172 g per tree), June (N 112 g and $K_2O$ 99 g per tree), and October (N 112 g and $K_2O$ 99 g per tree). At the same time, 1/3 or 2/3 of the conventional rate and none were applied to other trees, respectively. Non-application decreased shoot length and reduced number of unnecessary secondary shoots by 39% compared with the conventional rate, not affecting yield and weight, color, firmness, and soluble solids of fruits. No significant difference was also found in the yield and the fruit characteristics among the trees fertilized with different rates. Concentrations of soluble sugars, starch, N, and K of dormant shoots in March of the following year were not significantly changed by the different treatments of the previous year. There was no significant difference of shoot growth and yield among the treatments the following year when the same fertilization rate was supplied to all the trees. Results indicated that fertilization rate could be reduced to less than 1/3 of conventional rate to save the cost and stabilize shoot vigor when tree height is lowered by severe pruning.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.3
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• pp.380-388
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• 1999

본 논문에서는 완전삼트리를 재귀원형군에 임베딩하는 문제를 고려한다. 재귀원형군 G(N,d)는 N개의 노드와 N보다 작은 d의 거듭제곱에 의한 점프에지를 가지는 원형군그래프이다. 임베딩 문제를 해결하고자 본 논문에서는 노드수가 3k인 삼항트리 Tk새롭게 도입한다. 먼저 N개 이하의 정점을 가지는 삼항트리가 G(N, 2)와 G(N,3)의 부그래프임을 보인다. 또한 완전 삼진트리가 삼항트리에 연장률 2, 확장률2, 밀집률 2로 임베딩됨을 보인다. 이러한 결과들을 결합하면서 N개 이하의 정점을 가지는 완전삼진 트리가 재귀원형군G(2N, 2)과 G(2N, 3)에 연장률 2, 밀집률 2로 임베딩 가능하게 한다. 임베딩 과정에서 이용된 삼항트리는 2 -포트 방송모델에서 최소방송트리임을 보이고, 이를 이용하여 재귀원형군 G(2m, 2)가 2-포트 방송모델에서 최소방송시간을 가짐을 보인다.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.12
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• pp.880-884
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• 2006

In an edge-weighted(positive, negative, or zero weights are possible) tree, we want to solve the problem of finding a longest path such that the sum of the weights of the edges in tile path is non-negative. To find a longest non-negative path of a tree we present a sequential algorithm with O(n logn) time and a CREW PRAM parallel algorithm with $O(log^2n)$ time and O(n) processors. where n is the number of nodes in the tree.