• Journal of Astronomy and Space Sciences
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• v.14 no.1
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• pp.94-108
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• 1997

The temperature of the upper thermosphere is generally varied with the solar activity, and largely with geomagnetic activity in the high latitude. The data analyzed in this study are acquired at two ground stations, Thule Air Base($76,5{deg} N, 68.4{deg} W, A = 86{deg}$) and $S{psi}ndre Str{psi}mfjord (67.0{deg} N, 50.9{deg} W, A = 74{deg}$), Greenland. Both stations are located in the high latitude not only geographically but also geomagnetically. The terrestrial night glow at 6300 ${angs}$ from atomic oxygen has been observed from the two ground-based Fabry-Perot interferometers, during periods of 1986~1991 in Thule Air Base and 1986~1994 in $S{psi}ndre Str{psi}mfjord$. Some features noted in this study are as follows: (1) The correlation between the solar activity and the measured thermospheric temperature is highest in the case of $3{leq}Kp{leq}4$ in Thule, and increases with the geomagnetic activity in $S{psi}ndre Str{psi}mfjord$. (2) The measured temperatures at Thule is generally higher than those at $S{psi}ndre Str{psi}mfjord$, but the latter shows steeper slope with the solar activity. (3) The harmonic analysis shows that the diurnal variation(24hrs) is the main feature of the daily temperature variation with a temperature peak at about 13-14 LT (LT=UT-4). However, the semi-diurnal variation is evident during the period of weak solar activity. (4) Generally the predicted temperatures from both MSIS86 and VSH models are lower than the measured temperature, and this discrepancy grows as the solar activity increases. Therefore, we urge modelers to develope a new thermospheric model utilizing broader sets of measurements, especially for high solar activity.

• Korean Journal of Environment and Ecology
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• v.29 no.6
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• pp.895-906
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• 2015

This study was carried out to the structure of plant community from Sinseongam to Jungdaesa in Odaesan National Park, furthermore, it seeks to curate the basic data for planning of the Abies holophylla's forest management in Odaesan National Park. In order to identify the current ecological environment, this study explored the actual vegetation as primary research and set to twenty plots(i.e. $400m^2$) for analysing detailed structure of plant communities. The research methodology was qualitative analysis, therefore it used TWINSPAN and DCA analysis tools. Especially, TWINSPAN performed well in several comparisons of classification techniques, DCA is one of the ordination technique showed that the plant communities. The plant community was analysed classification and ordination by TWINSPAN and DCA, moreover it was analysed the structure of plant community such as importance percentage of woody species, DBH class distribution, the index of diversity and rate of sample tree growth. The main vegetation was A. holophylla-Quercus mongolica forest and Deciduous broad-leaved forest in the communities where located in low altitude and valley, whereas main vegetation where located in high altitude and slope was Q. mongolica forest. The research site's plant communities were classified four groups. In all of communities, A. holophylla was dominant species in main canopy layer, furthermore, the three communities (community I, II, III) are growing up next generation of A. holophylla excluding community IV. The communities (community I, II, III) can be sustained current status which dominates the A. holophylla communities, simultaneously, there might be expanded the Deciduous broad-leaved communities by Carpinus cordata, Betula schmidtii and so on. While, it showed that the community IV tended to be weaken the forces of A. holophylla, therefore the community IV can be transferred to C. cordata-Deciduous broad-leaved communities in the future. The age of sample trees was 79~128(i.e. A. holophylla), 75~87(i.e. Pinus koraiensis) and 190 years(i.e. Ulmus davidiana var. japonica). The index of Shannon's Species diversity (H') were ranged from 0.3889 to 1.3332 in the communities.

• Journal of Korean Society of Forest Science
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• v.87 no.4
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• pp.535-542
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• 1998

This study was carried out for the purpose of supplying the basic data for artificial forestation, natural regeneration and ecological conservation etc., and obtaining information on alpine vegetation, by establishing vegetation units on the basis of phytosociological classification of community and studying growth pattern on the basis of species composition, hierarchy structure and population dynamics, for Taxes cuspidata naturally growing at the alpine districts in Korea. The importance value of Taxus cuspidata by districts mostly showed above 100 in the upper story but at Mt. Chiri and Mt. Hanra communities its value was comparatively low. In the middle story it showed lower value than that of upper story and not quite showed at Mt. Chiri. Taxus cuspidata communities in the lower story were only in Mt. Hanra, Mt. Odae and Mt. Sobaek, and their importance values were about 10 which were relatively low values. The communities were classified into five groups as Taxus cuspidata-Males baccata var. mandshurica, Taxus cuspidata-Abies nephrolepis, Taxus cuspidata-Abies koreana, Taxus cuspidata-Acer mono and Taxus cuspidata-Euonymus quelpaertensis by TWINSPAN analysis. Taxus cuspidata-Abies koreana community was distributed at the northern aspect of the mountain ridges and at higher elevation than other communities and distributed. Taxus cuspidata-Acer mono community was relatively low than the others and distributed at the hillsides of mountain. And Taxus cuspidata-Euonymus quelpaertensis communities were distributed at the relatively high elevation and northern and eastern aspect of the mountain tap, and Taxus cuspidata-Malus baccata var. mandshurica communities were distributed at the medium elevation, and southern and eastern aspect of the mountain ridge. In the relation between communities and environmental factors, it was correlated with aspect, elevation and topography at the first axis, and elevation, slope at the second axis.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.302-311
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• 2018

Using cylindrical paper pot nursery method, three kinds of commercial tomatoes 'Dafnis', 'DOTAERANG DIA' and 'Maescala' were grafted onto a commercial rootstock 'B blocking'. From 10 to 40 days after graft-take, growth traits of seedlings were investigated by 0.5, 1.0 and 2.0S treatments of standard nutrient solution(S) for seedling growth, and top to root ratio(TRR), compactness(CP) and Dickson Quality Index(DQI) were calculated. Two weeks after transplanting of the seedlings under three different night temperature targeting to 10, 15, and $25^{\circ}C$, which were not precisely controlled, the relative growth rate (RGR) was investigated. The quantitative growth traits of grafted seedlings increased with increasing fertilizer concentration, and various range of seedling size could be produced. Compactness and DQI were significantly regressed (Adj $R^2=0.9480$). Short-term RGR after transplanting was higher at 1.0S treatment of standard nutrient solution at the seedling age of 30 days and 40 days after graft-take(DAGT). DQI and RGR were significantly regressed linearly at respective fertigation strength. Specially the diminishing slope of RGR was lower at 1.0S fertigation strength with the increase of DQI than others. The results indicate that DQI could be applied as a quality index of grafted tomato seedlings and the relation analysis between DQI and short-term RGR also could be used to determine the good quality seedlings of grafted tomato grown in cylindrical paper pot.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.1
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• pp.44-54
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• 2001

This study was conducted to estimate microclimate of natural deciduous forest in national forest of Pyungchang, Kangwon province and to investigate the effects of the microclimatic conditions on the periodic annual increment of diameter by site types. In this study, site was first classified by nine types considering both elevation (higher than 1,000 m, 700∼1,000 m, and lower than 700 m) and topographical conditions (ridge, slope and valley). For each of site types, diameter growth was measured by using increment borer and periodic annual increment of diameter was then analyzed. A topoclimatological technique, for estimating microclimatic conditions, which make use of empirical relationships between the topographical factor and the climatic normals in the study area was applied to produce monthly mean, maximum and minimum temperatures, relative humidity, precipitation and hours of sunshine. From these monthly estimtes, 17 weather variables such as warmth index, coldness index, index of aridity etc. which affect the diameter growth were computed for each of site types. The periodic annual increment of diameter was then correlated with and regressed on the 17 weather variables to examine effects of microclimatic conditions on the diameter growth by site types. From the correlation analysis, it was found that the diameter growth by site types was positively correlated with all of 17 weather variables except the warmth index. Especially, the conditions such as high relative humidity and large amount of sunshine hours provide favorable environment for the growth of diameter. On the other hand, it was also found that diameter growth was negatively iufluenced by warmth index. According to the regression analysis, the periodic annual increment of diameter could be well predicted by index of aridity and mean relative humidity for the growing season.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.259-267
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• 2006

Hydraulic conductivity is the rate of water flux on hydraulic gradient. The van Genuchten Mualem (VGM) model is frequently used for describing unsaturated state of soils, that is composed with the function of soil water potential and soil water content and requests various parameters. This study is to get the value of VGM parameters used Rosetta computer program based on neural network analysis method and to calculate VGM parameters. VGM parameters included Ko(effective saturated hydraulic conductivity), ${\theta}r$(residual soil water content), ${\theta}s$(saturated soil water content), L, n and m. The unsaturated hydraulic conductivity at 10 kPa was calculated by using Rosetta program. Unsaturated hydraulic conductivities of 17 soil series at 1, 3, 5, 7 kPa were also obtained by applying saturated hydraulic conductivity by disk tension infiltrometer based on Gardner and Wooding's equation. Water flow at the water potential of 3 kPa was very low except Namgye, Hagog, Baegsan, Sangju, Seogcheon, Yesan soil series. Unsaturated hydraulic conductivity at 1 kPa showed the highest value for Samgag soil series and was in order of Yesan, Hwabong, Hagog and Baegsan soil series. Those of Gacheon, Seocheon and Ugog soil series were very low. When the value by VGM was compared with the value by disc tension infiltrometer, there was a tendency with exponential function to soils without gravel but there was no tendency to soils including gravel. Conclusively, it would be limited that VGM model for unsaturated hydraulic conductivity analysis applies to Korean agricultural land including gravel and having steep slope, shallow soil depth.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.6
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• pp.329-333
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• 2006

Most of volcanic ash soils in South Korea are distributed in Jeju province which is an island placed on southern part of Korea and has steep slope mountain area. There are many soils containing high contents of organic matter (OM) derived from volcanic ash in Jejudo, also. Therefore, irrigation and drainage in volcanic ash soil different with general soil which has low OM content have to be applied with another management way, but studies searching appropriate methods for them are set on insufficient situation because the area of volcanic ash soil in South Korea is only 1.3% (130,000ha). This study was conducted for analysis of soil water content and irrigation quantity appropriate for crops cultivated in volcanic ash soil with high OM content. Although soils with different soil color have the same soil texture, soil water characteristics curve by soil color showed the difference of water retention capability by OM content. But, this characteristics classified with soil color could be unified by scaling technique with similitude analysis method which get dimensionless water content using a present water content, a residual water content and saturated water content (or water content at 10kPa). A relation of gravimetric soil water content (GSWC) and dimensionless water content by the results showed a form of power function. The dimensionless water content (DWC) express a relative saturation degree of present water content. This was also expressed by van Genuchten model which describe the relation between relative saturation degrees and matric potentials. These results on soil water characteristics curve (SWCC) of volcanic ash soil will be the basic of irrigation plan in area having high organic contents into soil.

• Korean Journal of Plant Resources
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• v.34 no.4
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• pp.297-310
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• 2021

Lonicera harae is a species of shrub in the Caprifoliaceae family, mostly distributed in East asia. So far, the related research on the genus of Lonicera is insufficient compared to the Lonicera japonica belonging to the same genus, which requires attention to domestic native plants. Therefore, this study aims to provide baseline data for cultivation and utilization through the growth environment and vegetation structure of the natural habitat. Lonicera harae, which plant found throughout the Korean Peninsula. The natural habitats of Lonicera harae is the forest, valley and lowland areas of the southern region. study examined 24 quadrats in 11 regions, including Gwangju, Wanju and Namhae. As a result, environmental condition of Lonicera harae was 8 to 483 m above sea level, normally distributed over 173 m, Slope was 5 to 25 degree with 8.5 degree on average. The list of plants were classified as a total of 229 taxa comprising 80 families, 166 genus, 198 species, 3 subspecies, 24 varieties, 4 forma. As a result of the clustering analysis, the three clusters were divided into three groups; Robinia pseudoacacia, Zelkova serrata, Larix kaempferi. Species diversity was 1.399 and Dominance and Evenness were found to be 0.978 and 0.022 respectively.

• Korean Journal of Environment and Ecology
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• v.34 no.6
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• pp.558-572
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• 2020

The purpose of this study was to classify the types of degraded areas of Mt. Jirisan section in Baekdudaegan and survey the actual condition of each damage type to use it as basic data for the direction of the restoration of damaged areas according to damage type based on the vegetation information of reference ecosystem. The analysis of the Mt. Jirisan section's actual degraded conditions showed that the total number of patches of degraded areas was 57, and the number of patches and size of degraded areas was higher at the low average altitude and gentle slope. Grasslands (deserted lands) and cultivated areas accounted for a high portion of the damage types, indicating that agricultural land use was a major damage factor. The survey on the conditions of 14 degraded areas showed that the types of damage were classified into the grassland, cultivated area, restoration area, logged-off land, and bare ground. The analysis of the degree of disturbance (the ratio of annual and biennial herb, urbanized index, and disturbance index) by each type showed that the simple single-layer vegetation structure mostly composed of the herbaceous and the degree of disturbance were high in the grassland and cultivated land. The double-layer vegetation structure appeared in the restoration area where the pine seedlings were planted, and the inflow of naturalized plants was especially high compared to other degraded areas due to disturbances caused by the restoration project and the nearby hiking trails. Although the inflow of naturalized plants was low because of high altitude in bare ground, the proportion of annual and biennial herb was high, indicating that all surveyed degraded areas were in early succession stages. The stand ordination by type of damage showed the restoration area on the I-axis, cultivated area, grassland, logged-off land, and bare ground in that order, indicating the arrangement by the damage type. Moreover, the stand ordination of the degraded areas and reference ecosystem based on floristic variation showed a clear difference in species composition. This study diagnosed the status of each damage type based on the reference ecosystem information according to the ecological restoration procedure and confirmed the difference in species composition between the diagnosis result and the reference ecosystem. These findings can be useful basic data for establishing the restoration goal and direction in the future.

• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.2
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• pp.23-40
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• 2022

Many constructed wetlands have been installed in dam reservoirs nationwide for ecological purification of watershed pollutants, but aging and reduced efficiency are becoming issues. To improve the management of constructed wetlands, an objective evaluation of structural suitability is required. This study evaluated 39 constructed wetlands of 15 dams. First, through fogus group interview(FGI), survey analysis, and analytic hierarchy process(AHP), eight evaluation items in the physical and vegetative aspects were selected and the evaluation criteria applied with weights were prepared. Second, as a result of the structural suitability evaluation, the average score of the overall constructed wetlands was 80.8, with 10 sites rated as 'good grade(91~100)', 22 sites rated as 'normal grade(71~90)' and 7 sites rated as 'poor grade(70 or less)'. The average score of physical structure evaluation was 52.6, with 14 sites rated as 'good', 21 sites as 'normal' and 4 sites as 'poor'. The suitability of location was good level in most constructed wetlands, but the water supply system, depth of water, ratio of length-to-width, and slope of flow channel were evaluated as 'normal' or less in constructed wetlands of 50% or more. Therefore, it was found that overall improvement was necessary for stable flow supply and flow improvement in the constructed wetland. The average score of vegetative structure evaluation was 28.2, and about 84% of them were identified as 'normal' or lower. As a result of analyzing the Spearman's correlation coefficient between the physical structure evaluation score and the vegetation structure evaluation score, there was a significant correlation(r = 0.728, p < 0.001), and it was found that each evaluation factor also influences each other. As a result of the case review of 6 constructed wetlands, the appropriateness of the evaluation results was confirmed, and it was found that the location, flow rate supply, and type of wetland had a great influence on the efficiency and operation of the wetland. Through this study, it will be possible to derive structural weaknesses of constructed wetlands in dam reservoirs as a nature-based solution, to prepare types and practical alternatives for improved management of each constructed wetland in the future, and to contribute to enhancing various environmental functions.