• Journal of applied mathematics & informatics
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• v.18 no.1_2
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• pp.639-647
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• 2005

We count the number of maximal independent sets of binary trees and planted plane trees.

• Journal of Environmental Science International
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• v.25 no.1
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• pp.57-65
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• 2016

This study's purpose was to provide basic data for the monitoring of ecological changes caused by change of vegetation structure of Abies koreana forest in a study site susceptible to climatic change in Yeongsil area of Hallasan Mountain, Jeju Island. Surveys revealed this: in Yeongsil area of Hallasan Mountain, per 1 ha of A. koreana forests, total number 1,781, and A. koreana number 989, accounting for 55.5% of the total number of trees. 190 A. koreana or 19.2% were found to be dead. For the number of individual trees by DBH, trees standing 5 cm - 10 cm tall formed the largest portion at 39.9%, and in the case of other trees except A. koreana, the number of individual trees below 5 cm accounted for 23.5% of the total number of trees. The survey of importance by height revealed this: at the top level, the importance of A. koreana was the highest at 106.23, but the sum of importance of temperate deciduous broad-leaved trees (Prunus maximowiczii, Quercus mongolica, and Taxus cuspidata) was higher at 142.84 than that of A. koreana. The analysis of species diversity revealed 0.645 species diversity for the tree layer and 0.817 for the shrub layer; for evenness, 0.549 for the tree layer and 0.664 for the shrub layer; for dominance value; 0.451 for the tree layer and 0.336 for the shrub layer. The analysis of tree vitality revealed that for the A. koreana forests in Yeongsil, the composition ratio of A. koreana by type is AS type>AL type>DS type>DB type, and that of the other trees is AL type>AS type>AF type>AB type. Compared with the forests in other areas, the A. koreana forests in the Yeongsil area have a very high occurrence rate of dead trees, and a high importance of trees is shown in the deciduous broad-leaved tree forests. Compared with the A. koreana forests in the Jindallaebat area, with the same level above sea, the vegetation structures are fast changing. Also, due to dryness and other non-physical environmental changes caused by a lack of rainwater and dry winds in winter, dead trees are fast increasing in number. Environmental changes such as climate change diversely affect the maintenance of A. koreana in individual areas, and if environmental changes are fast and continue long, of the A. koreana forest areas in the Hallasan Mountain, the A. koreana forests in the Yeongsil area will decrease fastest in number and will experience changes in the vegetation structure. Thus, it is necessary to survey the vegetation changes in A. koreana forests, which are distributed in all directions but are centered on Hallasan Mountain, and to thus conduct long-term monitoring and research.

• Journal of Industrial Technology
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• v.15
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• pp.235-244
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• 1995

In this paper, we propose a bulk-load algorithm for $B^+-trees$, the most widely used index structures in database systems. The main characteristic of our algorithm is to simultaneously process all the keys to be placed on each $B^+-trees$ page when accessing the page. This avoids the overhead for accessing the same page multiple times, which results from applying the $B^+-trees$ insertion algorithm repeatedly. For performance evaluation, we analyze our algorithm in terms of the number of disk accesses. The results show that the number of disk accesses excluding those in the redistribution process in identical to the number of $B^+-trees$ pages. Considering that the redistribution process is an unavoidable preprocessing step for bulk-loading, our algorithm requires just one disk access per $B^+-trees$ page, and therefore turns out to be optimal. We also present performance tendancy according to the changes of parameter values via simulation.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.2
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• pp.194-206
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• 1998

In 1977, Local governments' planting regulations for the development projects were established in accordance with the revised building law in Korea. A landscaped area, planting densities of trees and shrubs, a percentage of evergreen plants, minimum tree size and species were prescribed in the planting regulations. But the clauses for an excessive planting density and a high ratio of evergreen trees that the regulations includes, have been gradually in the way to a creative planting design, and raise a problem of poor growth of trees an a disordered planting landscape. Therefore, in this study the present planting regulations of 124 local governments throughout the country were analyzed and compared with 13 foreign local governments' of 4 countries ; Japan, the United States of America, Canada and Singapore. And the linitations and characteristics of the regulations are drawn as follows ; 1. The regulations focus on controlling the green spaces and plantings by quantitative methods such as controlling the number of trees and the landscaped area, which are inadequate for estimating the crown coverage of mature trees, and which areinadequate for estimating the crown coverage of mature trees, and implementing the function of polantings and the use of green spaces. 2. Minimums of tree densities are higher than those of foreign countries, especially higher about 10 times to 100 times than those of the United States of America. 3.Excessive number of evergreen trees and fruit trees should be planted under the present planting regulations, that results in constricting the creativity in planting design. 4. An article for using specific tree size, 2.0ms over in height makes it difficult to use a wide variety of different sizes of trees. And there is no incentive measures when larger trees are planted. To enhance the quality of green spaces and plantings, it is needed that the function and locating of green spaces and plantings have to be emphasized, and the planting density should be concerned about the mature tree size. The incentive measure to use various sizes of trees is also needed, and the regulations to use excessive number of evergreen trees or fruit trees should be loosened.

• Bulletin of the Korean Mathematical Society
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• v.59 no.1
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• pp.167-177
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• 2022

A vertex v of a graph G = (V, E) is said to ve-dominate every edge incident to v, as well as every edge adjacent to these incident edges. A set S ⊆ V is called a double vertex-edge dominating set if every edge of E is ve-dominated by at least two vertices of S. The minimum cardinality of a double vertex-edge dominating set of G is the double vertex-edge domination number γ_dve(G). In this paper, we provide an upper bound on the double vertex-edge domination number of trees in terms of the order n, the number of leaves and support vertices, and we characterize the trees attaining the upper bound. Finally, we design a polynomial time algorithm for computing the value of γ_dve(T) for any trees. This gives an answer of an open problem posed in [4].

• Journal of the Korean Data and Information Science Society
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• v.21 no.2
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• pp.371-377
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• 2010

In this study, we propose two informal hypothesis tests which may be useful in determining the number of trees in a random forest for use in classification. The first test declares that a case is 'easy' if the hypothesis of the equality of probabilities of two most popular classes is rejected. The second test declares that a case is 'hard' if the hypothesis that the relative difference or the margin of victory between the probabilities of two most popular classes is greater than or equal to some small number, say 0.05, is rejected. We propose to continue generating trees until all (or all but a small fraction) of the training cases are declared easy or hard. The advantage of combining the second test along with the first test is that the number of trees required to stop becomes much smaller than the first test only, where all (or all but a small fraction) of the training cases should be declared easy.

• Journal of the Korean Institute of Landscape Architecture
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• v.21 no.1
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• pp.31-50
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• 1993

This study was conducted to investigate the plants status of the woody landscape plants species of 38 elementary, middle, and high school in Iri city, and to obtain some fundamental information for development and use of native species of trees. The results are summarized as follows: 1. Landscape plants species of 38 elementary, middle and high school in Iri city was 55 families, 164 species, and 85, 045 trees and the average of landscape plants species of 17 elementary schools was 50.5 families, 3, 010 trees, on the other hand, middle and high school was 42.4 families, 1, 609 trees. 2. Plants species by type was Deciduous Broadleaved Tree 32.9%, Deciduous Broadleaved Shrub 25.6%, Evergreen Coniferous Tree 14.6%, Evergreen Broadleaved Shrub 9.7%, Vine 4.8%. Evergreen Trees on the other hand, according to the utilization rate 'others' was 32.2%. 3. The rate of plants species of the Evergreen Trees to the Deciduous (except Vine and 'others') was 34:66. on the other hand, rate of quantity was 50.5:49.5 and the rate of the trees to the shrubs(except Vine and 'others') was 58:42. to the plants species and to the quantity of the number of trees was 25.9:74.1. 4. Plants species of fruit plants of 38 elementary, middle and high school in Iri city was 31 species to the 164 species. The rate of frequency was Poncirus trifoliata 27.8%, Lycium chinense 25.1%, Ginkgo biloba 16.7%, to the quantity of the number of trees, fruit plants was 2, 605 trees to the 85, 045 trees and the frequency was 3%. 5. School trees and flowers of 38 elementary, middle and high school in Iri city were appointed 17 elementary school, on the other hand, middle and high schools were only 4 middle and high schools. Plants species of the best of frequency school tree was Zelkova serrata and school flower was Rosa spp.. 6. The rate of the native species to the introduced species was 73.8:26.2. on the other hand, the rate of quantity by the number of trees was 84.7:15.3 to the type, the rate of frequency of plants of native species Evergreen trees was Thuja orientalis, deciduous was Ginkgo biloba, Vine was Wisteria floribunda and 'others' was Sasa borealis. on the other hand, to the introduced species, Evergreen Trees was Juniperus chinensis. Deciduous Trees was Metasequoia glyptostroboides, and Vine was Vitis labrusca and 'others' was Phyllostachys pubescens. 7. As the fundament of the results of above the optimum selecting of woody landscape plants according to native species of trees was 29 families, 58 species. on the basis of 30 points, 28 points was 8 species Ginkgo biloba, Ulmus davidiana var. japonica, Parthenocissus tricuspidata, Elaeagnus umbellata, Fraxinus rhynchophylla, Weigela subsessilis, Koelreuteria paniculata, Lonicera japonica, 26 points was 27 species Thuja orientalis, Zelk ova serrata, Euonymus japonica etc., and 24 points was 23 species Populus tomen tiglandulosa, Juglans sinensis, Sophora japonica etc..

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.2
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• pp.269-286
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• 2011

In this paper, we study a problem that is concerning how to construct a delay-constrained multicast tree on a wireless mesh network (WMN) such that the number of serviced clients is maximized. In order to support high-quality and concurrent interference-free transmission streams, multiple radios are implemented in each mesh node in the WMNs. Instead of only orthogonal channels used for the multicast in the previous works, both orthogonal and partially overlapping channels are considered in this study. As a result, the number of links successfully allocated channels can be expected to be much larger than that of the approaches in which only orthogonal channels are considered. The number of serviced subscribers is then increased dramatically. Hence, the goal of this study is to find interference-free and delay-constrained multicast trees that can lead to the maximal number of serviced subscribers. This problem is referred as the MRDCM problem. Two heuristics, load-based greedy algorithm and load-based MCM algorithm, are developed for constructing multicast trees. Furthermore, two load-based channel assignment procedures are provided to allocate interference-free channels to the multicast trees. A set of experiments is designed to do performance, delay and efficiency comparisons for the multicast trees generated by all the approximation algorithms proposed in this study.

• Communications of the Korean Mathematical Society
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• v.18 no.1
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• pp.181-192
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• 2003

We count the numbers of independent dominating sets of rooted labeled trees, ordinary labeled trees, and recursive trees, respectively.

• The Journal of Natural Sciences
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• v.16 no.1
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• pp.77-86
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• 2005

The study was designed to learn about features of landscape trees and shrubs on an exclusive area-specific outer space planting plan in Noeun Apartment Complex in Daejeon Metropolitan City. the exclusive areas were no more than $60m^2$ and $85m^2$ and the landscape areas ranged from 15% and 30%, respectively according to exclusive area-to-plottage ratios. The study showed that trees were likely to be more densely planted in exclusive areas not exceeding $60m^2$ than in exclusive areas over $85m^2$. It also found that the greater the exclusive areas were, the larger the number of species became. Regardless of the size of an exclusive use, however, the species number of evergreen trees and shrubs remained small, while there was no remarkable difference in vegetation due largely to a massive influx of special trees or shrubs such as Eastern white pines (Pinus strobus) and Korean azaleas (Rhododendron yedoensis var. poukhanense). The introduction of trees with the height over four meters and the diameter of breast height (DBH) exceeding 15 meters was strictly limited to Japanese red pins (Pinus densiflora) and Japanese zelkovas (Zelkova serrata). In conclusion, it is necessary for us to introduce fresh species of trees and especially develop evergreen trees and shrubs to make the environment of the apartment complex more comfortable and make a vegetation experience feasible.