• Atmosphere
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• v.34 no.2
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• pp.177-185
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• 2024

As increasing global interest in renewable energy due to the ongoing climate crisis, there is a growing need for efficient technologies to manage such resources. This study focuses on the predictive skill of daily solar power generation using weather observation and forecast data. Meteorological data from the Korea Meteorological Administration and solar power generation data from the Korea Power Exchange were utilized for the period from January 2017 to May 2023, considering both inland (Daejeon) and coastal (Busan) regions. Temperature, wind speed, relative humidity, and precipitation were selected as relevant meteorological variables for solar power prediction. All data was preprocessed by removing their systematic components to use only their residuals and the residual of solar data were further processed with weighted adjustments for homoscedasticity. Four models, MLR (Multiple Linear Regression), RF (Random Forest), DNN (Deep Neural Network), and RNN (Recurrent Neural Network), were employed for solar power prediction and their performances were evaluated based on predicted values utilizing observed meteorological data (used as a reference), 1-day-ahead forecast data (referred to as fore1), and 2-day-ahead forecast data (fore2). DNN-based prediction model exhibits superior performance in both regions, with RNN performing the least effectively. However, MLR and RF demonstrate competitive performance comparable to DNN. The disparities in the performance of the four different models are less pronounced than anticipated, underscoring the pivotal role of fitting models using residuals. This emphasizes that the utilized preprocessing approach, specifically leveraging residuals, is poised to play a crucial role in the future of solar power generation forecasting.

• Microbiology and Biotechnology Letters
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• v.39 no.4
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• pp.317-323
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• 2011

Strain A-3, an amylase-producing bacteria, was isolated from coastal seawater near Daecheon in the Republic of Korea. It was seen to possess a single polar flagella and grow well, on ASW-YP agar plates, at temperatures of between $20-37^{\circ}C$. However, it grew more slowly at the temperatures of $15^{\circ}C$ and $40^{\circ}C$. Similarly, it was observed to grow abundantly, in an Artificial Sea Water-Yeast extract-Peptone (ASW-YP) liquid medium, in a pH range of 6-9, but not grow at pHs of 4-5 and a pH of 10. Strain A-3 was noted as being close to Pseudoalteromonas phenolica O-$BC30^T$, Pseudoalteromonas luteoviolacea $NCIMB1893^T$, Pseudoalteromonas rubra $ATCC29570^T$, and Pseudoalteromonas byunsanensis $FR1199^T$, with 98.30%, 97.86%, 97.78%, and 97.25% similarities respectively, in its 16S rRNA sequence. A phylogenetic tree revealed that strain A-3 and P. phenolica O-$BC30^T$ belong to a clade. However, strain A-3 differed from P. phenolica O-$BC30^T$ in relation to a number of physiological characteristics. Strain A-3 exhibited no growth above 5% NaCl concentrations, no utilization of D-glucose, D-mannose, D-maltose, or D-melibose, and no lipase (C-14) activity. All of these properties strongly indicate that strain A-3 is distant from P. phenolica O-$BC30^T$ and thus led us to name it Pseudoalteromonas sp. A-3. Pseudoalteromonas sp. A-3 produces ${\alpha}$-amylase throughout growth. Maximal amylase activities of 144.48 U/mL and 149.20 U/mL were seen at pH 7.0 and $37^{\circ}C$, respectively. Pseudoalteromonas sp. A-3's high, stable production of ${\alpha}$-amylase in addition to its biochemical features, such as alkalitolerance, suggest that it is a good candidate for industrial applications.

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.4
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• pp.224-236
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• 2002

A long-term growth simulation was performed at 496 land units in the western coastal plains (WCP) of North Korea to test the potential adaptability of each land unit for growing South Korean rice cultivars. The land units for rice cultivation (CZU), each of them represented by a geographically referenced 5 by 5 km grid tell, were identified by analyzing satellite remote sensing data. Surfaces of monthly climatic normals for daily maximum and minimum temperature, precipitation number of rain days and solar radiation were generated at a 1 by 1 km interval by spatial statistical methods using observed data at 51 synoptic weather stations in North and South Korea during 1981-2000. Grid cells felling within a same CZU and, at the same time, corresponding to the satellite data- identified rice growing pixels were extracted and aggregated to make a spatially explicit climatic normals relevant to the rice growing area of the CZU. Daily weather dataset for 30 years was randomly generated from the monthly climatic normals of each CZU. Growth and development parameters of CERES-rice model suitable for 11 major South Korean cultivars were derived from long-term field observations. Eight treatments comprised of 2 transplanting dates $\times$ 2 cropping systems $\times$ 2 irrigation methods were assigned to each cultivar. Each treatment was simulated with the randomly generated 30 years' daily weather data (from planting to physiological maturity) for 496 land units in WCP to simulate the growth and yield responses to the interannual climate variation. The same model was run with the input data from the 3 major crop experiment stations in South Korea to obtain a 30 year normal performance of each cultivar, which was used as a "reference" for comparison. Results were analyzed with respect to spatial and temporal variation in yield and maturity, and used to evaluate the suitability of each land unit for growing a specific South Korean cultivar. The results may be utilized as decision aids for agrotechnology transfer to North Korea, for example, germplasm evaluation, resource allocation and crop calendar preparation.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.36 no.1
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• pp.55-66
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• 2018

The cactus habitat in Jeju Island has a phytogeographically specific distribution in the East Asian region, and forms a unique landscape as the only native cactus (Opuntia ficus-indica (L.) Mill.) habitat in Korea. However, there has been no detailed investigation on the distribution of cacti in the habitat and no investigation on the diversity of the mixed composition of plants in the habitats and their correlation with the distribution of cactus populations. This study attempted to investigate the diversity of vascular plants in the Wollyeong-ri cactus habitat and record the actual distribution and trends of cactus distribution. In addition to the distribution characteristics of cacti, we also discuss the characteristics of species reflecting the characteristics of the habitat among the mixed population of plant species, as well as the biological and environmental factors that threaten the maintenance of cactus populations or require management for preservation of cacti. Considering the phenological character, we conducted the field surveys for flora identification six times between June 2015 and September 2017. The Engler classification system was used for the arrangement sequence and names of plants, and the Korean Plant Names Index was adopted for the Korean name of the species. The study results showed that the Wolryung-ri cactus habitat in Jeju Island has the characteristic physiognomy of an area dominated by cactus. For the vascular plants, a total of 125 taxa were identified, including 53 families, 104 genera, 109 species, 15 varieties and 1 forma. Endangered plants specified by the Ministry of Environment were not found. Two species, Cyrtomium falcatum and Asplenium incisum, were identified as the ferns, and no gymnosperms were found. In addition, 123 taxa of angiosperms, 91 taxa of dicotyledones and 32 taxa of monocotyledons were identified. The distributions of cacti were confirmed in 289 meshes corresponding to 59.3% of the total 487 meshes in the cactus protected area, which showed various coverage distributions ranging from 5% to 95%. Most of the meshes where no cacti were found are coastal areas with exposed basalt rocks where the soil depth has not developed or extremely restricted due to repeated waves, or areas where artificial facilities, grasslands, and observation paths have been constructed. On the other hand, there were 71 lattice points in 14.5% of the total area where the cactus showed 70% or higher dominance. Cacti are randomly distributed in these areas. They have adapted to the microhabitat environment and are found to be opportunistically distributed along the growable locations. Considering that the reproduction of cacti in the habitat is mostly dependent on parthenogenesis, the present distribution seems to reflect the potentially distributable regions of cacti in the habitat. Based on the results of field surveys, a management plan for conservation and protection of the protected areas has been proposed.

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.959-974
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• 2021

Forel-Ule Index (FUI) is an index which classifies the colors of inland and seawater exist in nature into 21 gradesranging from indigo blue to cola brown. FUI has been analyzed in connection with the eutrophication, water quality, and light characteristics of water systems in many studies, and the possibility as a new water quality index which simultaneously contains optical information of water quality parameters has been suggested. In thisstudy, Ocean Colour-Climate Change Initiative (OC-CCI) based 4 km FUI was spatially downscaled to the resolution of 500 m using the Geostationary Ocean Color Imager (GOCI) data and Random Forest (RF) machine learning. Then, the RF-derived FUI was examined in terms of its correlation with various water quality parameters measured in coastal areas and its spatial distribution and seasonal characteristics. The results showed that the RF-derived FUI resulted in higher accuracy (Coefficient of Determination (R²)=0.81, Root Mean Square Error (RMSE)=0.7784) than GOCI-derived FUI estimated by Pitarch's OC-CCI FUI algorithm (R²=0.72, RMSE=0.9708). RF-derived FUI showed a high correlation with five water quality parameters including Total Nitrogen, Total Phosphorus, Chlorophyll-a, Total Suspended Solids, Transparency with the correlation coefficients of 0.87, 0.88, 0.97, 0.65, and -0.98, respectively. The temporal pattern of the RF-derived FUI well reflected the physical relationship with various water quality parameters with a strong seasonality. The research findingssuggested the potential of the high resolution FUI in coastal water quality management in the Korean Peninsula.

• Korean Journal of Environment and Ecology
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• v.26 no.3
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• pp.426-436
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• 2012

This study was carried out to investigate actual vegetation, the structure of plant community, and ecological succession sere of coastal forest ecosystem in warm temperate climate zone, Taejongdae, Busan City, Korea to provide the basic data for planning of the forest management. As a result of analysis of actual vegetation, vegetation types divided into 35 types, and the area of survey site was $1,750,461m^2$. The ratio of vegetation type dominated by Pinus thunbergii was 80.7%, dominated by Quercus spp. was just 5.0%, and dominated by Carpinus tschonoskii was just 0.4%. Eighteen plots(size is $20m{\times}20m$) were set up and the results analyzed by DCA which is one of the ordination technique showed that the plant communities were divided into four groups which are community I(P. thunbergii community), community II(P. thunbergii-Quercus serrata community), community III(Q. serrata-P. thunbergii community), and community IV(Carpinus tschonoskii-P. thunbergii community). The age of community I was from 38 to 59 years old, that of community II was from 35 to 71 years old, that of community III was from 37 to 53 years old, that of community IV was from 50 to 72 years old, thus we supposed that the age of the study site is about from 38 to 72 years old. We supposed that the successional sere of the study site is in the early stage of ecological succession in the warm temperate climate zone. The dominant species will be changed from P. thunbergii to Q. serrata or Carpinus tschonoskii in the canopy layer, on the other hand, Eurya japonica will be dominant species in the understory layer, and E. japonica and Trachelospermum asiaticum var. intermediumwill be dominant species in the shrub layer for a while. According to the index of Shnnon's diversity(unit: $400m^2$), community I ranged from 0.8640 to 1.3986, community II was from 0.1731 to 1.1885, community III was from 0.8250 to 1.0042, and community IV was from 0.3436 to 0.6986.

• Journal of the Korean Geographical Society
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• v.41 no.2 s.113
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• pp.168-187
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• 2006

Windy meteorological conditions and dried fire fuels due to higher atmospheric instability and dryness in the lower troposphere can exacerbate fire controls and result in more losses of forest resources and residential properties due to enhanced large wildland fires. Long-term (1979-2005) climatology of the Haines Index reconstructed in this study reveals that spatial patterns and intra-annual variability of the atmospheric instability and dryness in the lower troposphere affect the frequency of wildland fire incidences over the Korean Peninsula. Exponential regression models verify that daily high Haines Index and its monthly frequency has statistically significant correlations with the frequency of the wildland fire occurrences during the fire season (December-April) in South Korea. According to the climatic maps of the Haines Index created by the Geographic Information System (GIS) using the Digital Elevation Model (DEM), the lowlands below 500m from the mean sea level in the northwestern regions of the Korean Peninsula demonstrates the high frequency of the Haines Index equal to or greater than five in April and May. The annual frequency of the high Haines Index represents an increasing trend across the Korean Peninsula since the mid-1990s, particularly in Gyeongsangbuk-do and along the eastern coastal areas. The composite of synoptic weather maps at 500hPa for extreme events, in which the high Haines Index lasted for several days consecutively, illustrates that the cold low pressure system developed around the Sea of Okhotsk in the extreme event period enhances the pressure gradient and westerly wind speed over the Korean Peninsula. These results demonstrate the need for further consideration of the spatial-temporal characteristics of vertical atmospheric components, such as atmospheric instability and dryness, in the current Korean fire prediction system.

• Korean Journal of Environment and Ecology
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• v.35 no.6
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• pp.579-593
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• 2021

In order to understand the types of vegetation in warm temperate-climate zones, vegetation was investigated in several island areas in Jeollanam-do (Jindo, Wando, Gangjin, Goheung, and Yeosu). The evaluation standard for degraded level of warm temperate forests were proposed based on the importance percentage (IP) in canopy layer of the evergreen broad-leaf forests and the number of arboreal evergreen broad-leaf species. Through these measurements, the restoration types and techniques for each degraded level were estimated, and it is intended to be used in establishing restoration plans for the southwest coast island area. The vegetation was analyzed using the two-way indicator species analysis (TWINSPAN) method using survey data of 307 plots. As a result, it was divided into 8 communities, and the appearance characteristics of evergreen broad-leaf species were identified in each community. Community I was located on the lower slope at an altitude of 86.6 m, and Neolitsea sericea and Castanopsis sieboldii were dominant. Communities II and III were the vegetation types that appear on the coast below an altitude of 10.5 to 22.5 m, and Machilus thunbergii, Cinnamomum japonicum, N. sericea, and C. sieboldii were dominant. Communities IV and V were vegetation types that appeared in the lower and middle slops between the altitudes of 71.9 to 153.4m, and C. sieboldii was dominant. In community VI, the N. sericea was dominant in the lower and middle slops at an altitude of 166.9 m. The last communities VII and VIII were the vegetation types that appeared on the middle slop at an altitude of 187.8 to 246.2 m. Also, Quercus acuta and Q. salicina were present. In summary, the evergreen broad-leaf forests dominated by M. thunbergii, C. japonicum, and N. sericea appeared mainly in the coastal areas of the lowlands. The community of C. sieboldii was distributed higher inland than this community. The communities that appeared mainly in the inland highlands at levels above these two communities were Q. acuta and Q. salicina. The degraded level was classified as 0 to V, according to the IP of arboreal evergreen broad-leaf species and the number of arboreal evergreen broad-leaf species. According to the degraded level, the restoration types (preservation, induction, improvement, creation) and the restoration techniques were determined.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.1
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• pp.100-113
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• 2007

In Korea, there has been no revegetation applicable standard for slopes formed by road construction work up to now, so revegetation work has been done using mostly foreign varieties in the manner of early revegetation. However, foreign varieties have some shortcomings; for example, they tend to be dried to death after construction work. Besides, due to the rift in the supporting soil, these revegetated varieties are often displaced from the slopes. Thus, the Ministry of Construction & Transportation on July, 2005 established revegetation standard on the slopes suited for the natural eco-system of Korea and organized positively recommending directions for using self-sewn plants growing near the slopes in overall consideration of soil, weather, regional conditions. The locations specified in this direction are the slopes at the road construction jobsite like the expressway, highways, and local roads. In addition, the Ministry's standard and directions stipulated that damaged slopes's natural environment and eco-system due to various road construction work should be restored, and thus a feeling of stability and pleasantness should be provided to road users as well. Also, the Ministry tried to select seed plants and revegetation measures suited for surrounding environment to put the environment-friendly slope revegetation measures into practice through the test revegetation work in order to prevent illegal construction practices and to improve the quality of revegetation. According to the direction, revegetation districts aimed at the slopes are divided into three ones in consideration of weather environment, regional environment, and forest environment as follows : national territory's core ecological green-land based district centering on the Taebaek Mountains; coastal ecosystem district including islands off the coast; inland eco-system district. The combination of revegetation plants according to environment revegetation districts, should be executed by dividing into herb-oriented type, woody plant colony type, and bio-species versatility restoration type, and the selection of seeding plants should be done in the presence of a supervisor and through test construction results and technology counseling from a specialist in natural eco-system restoration and revegetation measure seed combination standard according to environment revegetation districts. This direction will be executed in the manner of monitoring until the yea 2008 and 2009 it will be finalized and enforced on December, 2009.

• The Korean Journal of Quaternary Research
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• v.14 no.1
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• pp.33-48
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• 2000

Vegetation disturbance history of the Korean Peninsula from the Palaeolithic Age to the Koryo Dynasty (1392) has reconstructed by the use of various data sources. Active vegetation disturbance, which has begun during the Neolithic Age, seems to be more widespread on lowland and coastal areas in the early stages, but later expanded into inland areas. The ploughing of a field and the selective cutting of certain trees, such as oak trees, nettle trees and pine trees are noticeable, and eventually caused deforestation during the Bronze Age. The use of iron tools of the Iron Age has enabled the forest clearing to develope the dry fields. During the Three Kingdoms period (BC 57∼AD 918) extensive deforestation has maintained for the development of cultivated fields, as well as other activities, such as timber, lumbering, production of iron farm implement, ploughing by cattle. The encouragement of disafforestation on mountain slope and creation of terraced field during the Koryo Dynasty (918∼1392) has caused the deforestation over the country, along with the consumption of large amount of wood and timber for fire-wood, ship-building, mining, xylography and so on.