• The Korean Journal of Ecology
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• v.28 no.3
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• pp.149-156
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• 2005

This study was conducted to elucidate the relationship between the aboveground vegetation structure and fine roots of the topsoil (<15m), and thereafter to obtain the regression models for the estimation of the fine roots of the topsoil using the aboveground vegetation values in the burned forest areas, Korea. The FRT (fine roots of the top soil) as well as the aboveground vegetation structure showed spatial variation in the earlier successional stages after forest fire. The fine roots (<2 mm) of the topsoil in the earlier successional stages than the first 3 year after forest fire showed the range from 3 to 166 g $DM/m^2$. The FRT in the naturally regenerated sites and planted sites after forest fire was closely correlated with the vegetation indices, especially lvc, representing the development status of the aboveground vegetation. The FRT in the terrace seeding work sites after forest fire was closely correlated with year elapsed after terrace seeding work. The FRT in the terrace seeding work sites showed the much higher values because of the vigorous growth of grass species than the other sites. In the naturally regenerated sites, the FRT showed the parabola form according to the increment of aboveground vegetation value (Ivc). Although the aboveground vegetation value (Ivc) showed a tendency to increase logarithmically during the secondary succession after forest fire, the estimated fine roots of the topsoil was depicted the parabola form showing the gradual increment until the first 15 years and slight decrease thereafter. Decrease of FRT in the later successional stage showing the high vegetation value may be caused by increment of the woody species contribution to the vegetation value (Ivc). Our results represented that the aboveground vegetation value (Ivc) can be used to the estimation of the fine roots of the topsoil in burned forest areas.

• The Korean Journal of Applied Statistics
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• v.30 no.3
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• pp.363-376
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• 2017

The insurance market is saturated and its growth engine is exhausted; consequently, the insurance industry is now in a low growth period with insurance companies that face a fierce competitive environment. In such a situation, it will be an important issue to find the probability distributions that can explain the flow of insurance claims, which are the basis of the actuarial calculation of the insurance product. Insurance claims are generally known to be well fitted by lognormal distributions or Pareto distributions biased to the left with a thick tail. In recent years, skew normal distributions or skew t distributions have been considered reasonable distributions for describing insurance claims. Cooray and Ananda (2005) proposed a composite lognormal-Pareto distribution that has the advantages of both lognormal and Pareto distributions and they also showed the composite distribution has a higher fitness than single distributions. In this paper, we introduce new composite distributions based on skew normal distributions or skew t distributions and apply them to Danish fire insurance claim data and US indemnity loss data to compare their performance with the other composite distributions and single distributions.

• Journal of Forest and Environmental Science
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• v.19 no.1
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• pp.99-107
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• 2003

For the investigation of the potentials of ectomycorrhizal (ECM) fungi on pine seedlings for reforestation on fire-damaged forest lands, six months old seedlings of Pinus densiflora, which were artificially inoculated or non-inoculated with Pisolithus tinctorius, were transplanted into the fire-damaged forest land. Seedling mortality was recorded as 3.5% for the seedlings inoculated with P. tinctorius at three months after transplanting, while it was 70.5% for the non-inoculated seedlings. Mycorrhizal root formation was shown as typically Y-branched type, and thier rate was 82% for inoculated seedlings, but it was 52% for non-inoculated. Comaprisons in seedling height, fresh weight, and dry weight between pine seedlings inoculated or non-inoculated with P. tinctorius at every 3 months till 9 months after transplanting showed that the inoculated seedlings were much better in all criteria as compared to the non-inoculated at the level of 63%, 35%, 18% in seedling height, 206%, 114%, 70% in fresh weight, and 187%, 109%, 63% in dry weight, respectively. The percentages were decreased by the elapse of time, which indicate that P. tinctorius give a growth-stimulating effects on seedlings at the early stage. T/R ratio for inoculated and non-inoculated seedlings after 9 months was 1.75 and 1.90, respectively.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.3
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• pp.207-216
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• 2015

The study was conducted to determine the effects of forest restoration methods and stand structure on solar radiation, air temperature, relative humidity, soil temperature, and soil water content, based on volume, in forest stand after forest fire. The changes of the micro-climate elements in naturally and artificially restored forest after forest fire were measured in Goseong and Samcheok, Gangwon province. Pinus spp. were commonly appeared in ridges, barren lands or planted areas of the study sites while the other areas were dominated by Quercus spp. In the early stage, trees in the naturally regenerated site grow better than the trees in artificially rehabilitated site. However, the growth ratio rapidly decreased by time passed in natural regeneration area. The environmental conditions (solar radiation, air temperature, relative humidity, soil temperature and soil water content) were significantly different by the regions and the methods (p<.05). However, the coefficients of variations of the environmental conditions were not significantly different at 95% confidence level. As the coverage and tree height in crown layer increased, the relative humidity and soil water content were increased while the temperature and solar radiation were decreased. Especially, the relative humidity, solar radiation, and soil water content were clearly affected by the tree height and coverage ratio ($R^2$ means from 0.628 to 0.924). Even though the data should have collected at least more than 5 years in meteorological analysis, the two year results show some clear relationship between forest structure and microclimate elements.

• Korean Journal of Remote Sensing
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• v.38 no.5_2
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• pp.765-779
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• 2022

This study evaluates the accuracy in identifying the burned area in South Korea using multi-temporal data from Sentinel-2 MSI and Landsat 8/9 OLI. Spectral indices such as the Difference Normalized Burn Ratio (dNBR), Relative Difference Normalized Burn Ratio (RdNBR), and Burned Area Index (BAI) were used to identify the burned area in the March 2022 forest fire in Uljin. Based on the results of six indices, the accuracy to detect the burned area was assessed for four satellites using Sentinel-2 and Landsat 8/9, respectively. Sentinel-2 and Landsat 8/9 produce images every 16 and 10 days, respectively, although it is difficult to acquire clear images due to clouds. Furthermore, using images taken before and after a forest fire to examine the burned area results in a rapid shift because vegetation growth in South Korea began in April, making it difficult to detect. Because Sentinel-2 and Landsat 8/9 images from February to May are based on the same date, this study is able to compare the indices with a relatively high detection accuracy and gets over the temporal resolution limitation. The results of this study are expected to be applied in the development of new indices to detect burned areas and indices that are optimized to detect South Korean forest fires.

• Journal of the Society of Disaster Information
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• v.13 no.1
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• pp.15-25
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• 2017

Since the late 19th century, the annual average temperature of the Earth has risen due to excessive emission of greenhouse gases, and abnormal weather phenomena such as heavy rain and heavy snowfall have been increasing frequently all over the world. In a city with high population growth due to high economic growth, fire and terrorist accidents can cause serious property damage and human casualties. The purpose of this study is to propose the need for evacuated facilities to protect victims, and suggest adequate shelters' size which can be protectable them. In spite of the Ministry of Public Safety and Security designated 3.3 square meters of per capita capacity, they does not specify the basis about setting this criterion.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.1
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• pp.33-37
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• 2008

The effects of Cu and Sb on the microstructure and mechanical properties of Sn-Sb-Cu-Ni-Cd whitemetal were investigated. Any compound phase was not observed in the whitemetal with 0.05 wt% Cu, while as the Cu content was increased, star- or needle-like $Cu_6Sn_5$ phases were found. The tensile strength gradually increased with Cu up to 5 % and then remained almost constant with Cu content above 5 %, while the hardness continuously increased with Cu content because of the increased hard $Cu_6Sn_5$ phases. As the Sb content increased, SbSn cuboids were present as well as $Cu_6Sn_5$. The tensile steength and hardness continuously increased and the elongation decreased with Sb content.

• Journal of the Korean Institute of Landscape Architecture
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• v.15 no.3
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• pp.11-19
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• 1988

The purpose of this study is to investigate ways to control the wind dispersal of contton-wrapped seeds of such poplars and willows as Poplus alba, P. tomentiglandulosa, P. euramericana, P. deltoides, and Salix pseudo-lasiogyne. These trees are hated by many people because of their seeds blowing all over the place during May. These cottony seeds can be nuisance to various types of outdoor activities, pose safely threat to drivers, become fire hazards during prolonged spring dry spells, and cause many types of health hazards of allergy such as sneezing. rhinitis, asthma, and skin rashes. Four control methods can be used to resolve the problem. First, pruning can be a solution, but it is unsatisfactory in terms of costs and outcome. Second, planting of male trees only can be a solution, but it is hard to identify sexes of saplings. Third, female trees can he replaced with other species. But it requires high costs and takes at least ten years to functionally replace the removed ones. As an alternative to such unsatisfactory control methods, the possibility of applying plant growth regulators has been investigated since 1983. During the pre-test, various concentrations and mixtures of them were either sprayed or injected, but failed to achieve any promising results. But the injection of a mixture made up of 0.75g of 2-chloroethane phosphonic acid with 0.2 mg of GA in 300cc water in the end of March produced premature falling of almost all aments and capsules of treated poplars and willows. It was found that the effect of the injection lasts two years. The results of the main experiment of 1987 can be summarized as follows ; First, the injection of the mixture of 2-chloroethane phosphonic acid and GA increases the premature abscisin of aments and capsules, thus reducing the wind dispersal of the cottony seeds of S. pseudolasiogyne, P. tomentiglandulosa, and P. euramericana 1644.09, 1200.61, and 1485.11 times, respectively, than that of the naural abscisin, It is estimated that the average number of wind-blown seeds reduced are approximatively 6,185,100, 4062,900, and 2,830,670 per tree, respectively. Second, the treatment causes no observable side effects on the growth of the samples tested.

• The Plant Pathology Journal
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• v.39 no.4
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• pp.397-408
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• 2023

Fire blight disease, caused by Erwinia amylovora, is a devastating affliction in apple cultivation worldwide. Chemical pesticides have exhibited limited effectiveness in controlling the disease, and biological control options for treating fruit trees are limited. Therefore, a relatively large-scale survey is necessary to develop microbial agents for apple trees. Here we collected healthy apple trees from across the country to identify common and core bacterial taxa. We analyzed the endophytic bacterial communities in leaves and twigs and discovered that the twig bacterial communities were more conserved than those in the leaves, regardless of the origin of the sample. This finding indicates that specific endophytic taxa are consistently present in healthy apple trees and may be involved in vital functions such as disease prevention and growth. Furthermore, we compared the community metabolite pathway expression rates of these endophyte communities with those of E. amylovora infected apple trees and discovered that the endophyte communities in healthy apple trees not only had similar community structures but also similar metabolite pathway expression rates. Additionally, Pseudomonas and Methylobacterium-Methylorobrum were the dominant taxa in all healthy apple trees. Our findings provide valuable insights into the potential roles of endophytes in healthy apple trees and inform the development of strategies for enhancing apple growth and resilience. Moreover, the similarity in cluster structure and pathway analysis between healthy orchards was mutually reinforcing, demonstrating the power of microbiome analysis as a tool for identifying factors that contribute to plant health.

• Bulletin of the Korean Chemical Society
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• v.29 no.6
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• pp.1137-1140
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• 2008

M1 RNA, the catalytic subunit of Escherichia coli RNase P, is an essential ribozyme that processes the 5' leader sequence of tRNA precursors (ptRNAs). Using KS2003, an E. coli strain generating only low levels of M1 RNA, which showed growth defects, we examined whether M1 RNA is involved in polycistronic mRNA processing or degradation. Microarray analysis of total RNA from KS2003 revealed six polycistronic operon mRNAs (acpP-fabF, cysDNC, flgAMN, lepAB, phoPQ, and puuCBE) showing large differences in expression between the adjacent genes in the same mRNA transcript compared with the KS2001 wild type strain. Model substrates spanning an adjacent pair of genes for each polycistronic mRNA were tested for RNase P cleavage in vitro. Five model RNAs (cysNC, flgMN, lepAB, phoPQ, and puuBE) were cleaved by RNase P holoenzyme but not by M1 RNA alone. However, the cleavages occurred at non-ptRNA-like cleavage sites, with much less efficiency than the cleavage of ptRNA. Since cleavage products generated by RNase P from a polycistronic mRNA can have different in vivo stabilities, our results suggest that RNase P cleavage may lead to differential expression of each cistron.