• Journal of Forest and Environmental Science
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• 제27권1호
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• pp.47-54
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• 2011

Allometry and basal area equations were developed with various tree measurement variables for the major species; Quercus variabilis, Quercus mongolica, Pinus koraiensis and Larix leptolepis in Korea. For allometry models, the relationships between total height-DBH, crown width-DBH, height to the widest portion of the crown-total height, and height to base of crown-total height were investigated. Multiple regression methods were used to relate annual basal area growth to tree variables of initial size (DBH, total height, and crown width), relative size (relative diameter and relative height) as well as competition measures (competition index, crown class, and live crown ratio).

• Journal of the Korean Society of Safety
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• 제35권1호
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• pp.97-106
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• 2020

The objective of this paper is to suggest a new quantification method for multi-unit probabilistic safety assessment (PSA) that removes the overestimation error caused by the existing delete-term approximation (DTA) based quantification method. So far, for the actual plant PSA model quantification, a fault tree with negates have been solved by the DTA method. It is well known that the DTA method induces overestimated core damage frequency (CDF) of nuclear power plant (NPP). If a PSA fault tree has negates and non-rare events, the overestimation in CDF drastically increases. Since multi-unit seismic PSA model has plant level negates and many non-rare events in the fault tree, it should be very carefully quantified in order to avoid CDF overestimation. Multi-unit PSA fault tree has normal gates and negates that represent each NPP status. The NPP status means core damage or non-core damage state of individual NPPs. The non-core damage state of a NPP is modeled in the fault tree by using a negate (a NOT gate). Authors reviewed and compared (1) quantification methods that generate exact or approximate Boolean solutions from a fault tree, (2) DTA method generating approximate Boolean solution by solving negates in a fault tree, and (3) probability calculation methods from the Boolean solutions generated by exact quantification methods or DTA method. Based on the review and comparison, a new intersection removal by probability (IRBP) method is suggested in this study for the multi-unit PSA. If the IRBP method is adopted, multi-unit PSA fault tree can be quantified without the overestimation error that is caused by the direct application of DTA method. That is, the extremely overestimated CDF can be avoided and accurate CDF can be calculated by using the IRBP method. The accuracy of the IRBP method was validated by simple multi-unit PSA models. The necessity of the IRBP method was demonstrated by the actual plant multi-unit seismic PSA models.

• Korean Journal of Environment and Ecology
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• 제27권5호
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• pp.544-549
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• 2013

We studied the habitat sites of Siberian flying squirrel in Guhak-ri, Sillim-myeon, Wonju-si, Gangwon-do from March to April in 2009. We were found total 30 points of inhabitation trace types; nests 15 points(Tree nest types were 13 points, used Tree hole types hole types were 2 points) and droppings 15 points. We observed 3 individuals of Siberian flying squirrels and founded that 2 individuals of them used tree holes, and another individual used tree nest which were located in branches of Pinus densiflora. Most utilized nest trees of Siberian flying squirrel were Larix leptolepis, and also used Pinus densiflora, Betula davurica, Styrax japonica, Cornus controversa, Acer mono. Droppings trees were Prunus sargentii, Cornus controversa, Quercus xmccormickii, Acer palmatum, Acer palmatum, Betula davurica. Through the observation, we defined that flying squirrels mainly used Conifer trees as nest sites, and decideous trees as droppings.

• Journal of the Korean Institute of Intelligent Systems
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• 제21권3호
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• pp.317-322
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• 2011

Korean adults' internet addiction diagnosis measure, K-scale developed by Korea National Information Society Agency (NIA), has composed of 4 categories including 20 items. This scale can diagnose user's internet addiction with individual's questionnaire items. Most of previous research works were tried to know reasons of internet addiction and to judge whether adolescents are addicted or not with their samples. In this research, it is the goal to find the key component to judge individual's internet addiction by using a decision tree in the data mining field and a principal component analysis in statistics. From the experimental results, we would discover that tolerance and preoccupation factor is the most important one to affect adult's internet addiction.

• The Korean Journal of Ecology
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• 제16권1호
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• pp.75-91
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• 1993

Structure and dynamics of Abies koreana community in Mt. Gaya were studied to provide the basic data for conservation of Abies koreana community, an endemic species in Korea. A. koreana community of this study site was composed of tree layer (4~7m), subtree layer (2~4m), shrub layer (1~2m), and herb layer (below 1m). The heights of tree and subtree layers were low. Floristic composition showed that this study site was subalpine and dry site. In frequency distribution diagram of diameter classes of major species consisting of A. koreana community, those of both A. koreana and other species showed reverse J-shaped types. From these results, it was estimated that A. koreana community of this site might be maintained continuously as a stable climax state like present state. In the spatal distribution diagram of major species, saplings of A. koreana were established under the canopy of A. koreana and Pinus koraiensis and under the dead tree of A. koreana. From these results, it was known that A. koreana saplings were recruited before the community was disturbed and regeneration was accomplished by advance regeneration pattern, in which these saplings established before occurrence of disturbance fill with open site originated from death of mature tree. Growth of annual rings was variable among individuals, it was estimated that such variation was originated in that growth of each individual relates to microclimatic conditions rather than macroclimatic ones. Ecological longevity of A. koreana in this study site estimated by disturbance types and age of dead trees was about 120 years.

• The Plant Pathology Journal
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• 제30권1호
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• pp.43-50
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• 2014

Microorganisms have many roles in nature. They may act as decomposers that obtain nutrients from dead materials, while some are pathogens that cause diseases in animals, insects, and plants. Some are symbionts that enhance plant growth, such as arbuscular mycorrhizae and nitrogen fixation bacteria. However, roles of plant pathogens and diseases in natural ecosystems are still poorly understood. Thus, the current study addressed this deficiency by investigating possible roles of plant diseases in natural ecosystems, particularly, their positive effects on arthropod diversity. In this study, the model system was the oak tree (Quercus spp.) and the canker disease caused by Annulohypoxylon truncatum, and its effects on arthropod diversity. The oak tree site contained 44 oak trees; 31 had canker disease symptoms while 13 were disease-free. A total of 370 individual arthropods were detected at the site during the survey period. The arthropods belonged to 25 species, 17 families, and seven orders. Interestingly, the cankered trees had significantly higher biodiversity and richness compared with the canker-free trees. This study clearly demonstrated that arthropod diversity was supported by the oak tree canker disease.

• Journal of Korean Society for Geospatial Information Science
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• 제5권2호
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• pp.45-54
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• 1997

A mathodology to manage effectively urban open space using GIS(Geographic Information System) was developed to explore the methology of efficient urban open space management focusing on landscaped trees. Cartographic modeling technique was used for practical use of GIS as a case study of the Childeren's park in Kwangju city. First, spatial and attribute information for efficient landscaped tree management was acqired through the development of a tree management cartographic model. Second the information of location and the attribute of individual trees can be applied as a means of decision making in tree management. Thira optimal path of tree management and priority of management in work process of the selected urban open space could be determined according to the objective of park management.

• Journal of Korean Society for Atmospheric Environment
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• 제18권6호
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• pp.515-525
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• 2002

A field study was conducted to estimate the emission rate of biogenic volatile organic compounds (BVOCs) from pine trees. In addition, the influences of meteological variables on their distribution characteristics have been investigated. A vegetation enclosure chamber was designed and constructed of Tedlar bag and acril. Sorbent tubes made up of Tenax TA and Carbotrap were used to collect biogenic VOCs emitted from each individual tree. Analysis of BVOCs was performed using a GC-FID system. The fundamental analytical parameters including linearity, retention time, recovery efficiency, and breakthrough volume were examined and verified for the determination of monoterpene emission rates. Total average concentration of each component is found to be $\alpha$-pinene (16.5), $\beta$-pinene (4.61) from pine trees, and $\alpha$-pinene (42.4), $\beta$-pinene (18.7 ng(gdw)$^{-1}$ hr$^{-1}$ ) from Korean pine trees. On the basis of our study, $\alpha$-pinene was found to be the major monoterpene emitted from both pine and Korean pine trees which were accompanied by $\beta$-pinene, camphene, and limonene. In ambient air, variable monoterpene compositions of emissions from pine trees were similar to Korean pine trees. Emission rates of monoterpene from each tree were found to depend on such parameters as temperature and solar radiation.

• Proceedings of the KIEE Conference
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2330-2332
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• 1998

This paper suggests a method to recognize the various defect patterns of cold mill strip using binary decision tree automatically constructed by genetic algorithm. The genetic algorithm and K-means algorithm were used to select a subset of the suitable features at each node in binary decision tree. The feature subset with maximum fitness is chosen and the patterns are classified into two classes by a linear decision boundary. This process was repeated at each node until all the patterns are classified into individual classes. The final recognizer is accomplished by neural network learning of a set of standard patterns at each node. Binary decision tree classifier was applied to the recognition of the defect patterns of cold mill strip and the experimental results were given to demonstrate the usefulness of the proposed scheme.

• Journal of Forest and Environmental Science
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• 제33권4호
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• pp.270-280
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• 2017

Selection of superior phenotypes of fruit trees and products based on established criteria by local people is a prerequisite for future species domestication and conservation. Thus the study objective was to identify the local people's perceptions and preferences on baobab trees and products. A sample of 142 respondents was randomly selected using structured interviews in Blue Nile and North Kordofan, Sudan in 2013. Descriptive analysis was employed using SPSS and Excel programs. The study results indicated that local people use the morphological characteristics of the tree (leaves, fruits, seeds, kernels and bark) to differentiate individual trees. Based on the perceptions, local people recorded trees with delicious leaves, white pulp color, big fruit size and mature capsule size, and high pulp yield as criteria for differentiating between baobab trees in the study areas. In contrast, the undesirable traits were connected to trees with acidic pulp, slimy pulp, bitter leaves, and low pulp yield. The study concluded that the ethnobotanical knowledge of the baobab tree and its products may play an important role in tree domestication and improvement in Sudan. However, further research on tree genetics is needed to complement the ethnobotanical knowledge for baobab resources domestication and conservation.