• Korean Journal of Soil Science and Fertilizer
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• v.41 no.5
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• pp.303-309
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• 2008

The physico-chemical properties of the rainfall interception culture (85 sites) and the open field culture soils (85 sites) in the area of Gochang-gun, Jeollabuk-do were surveyed. Soil textural distribution of the rainfall interception culture and the open field culture soils was 74% and 64% for silt loam, 16% and 35% for loam, and 10% and 1% for clay, respectively. The percentage of aggregate rates was higher in the open field culture soils (60.06%) than rainfall interception culture soils (55.84%). Electrical conductivity, exchangeable cations, and anions in the rainfall interception culture soils were higher than those in open field soils. Specially, accumulated amount of anion in rainfall interception culture soils was remarkably higher 2~3 times than open field culture soils. The results from the analyses of rainfall interception culture soils suggested that the most critical problem is the salts accumulation caused by over-fertilization of chemical fertilizer and compost. Therefore, application rates of chemical fertilizer and compost should be controlled in order to conservation of soil and water for sustainable agriculture.

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.127-136
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• 2020

This study was conducted to investigate the population characteristics of Nile tilapia (Oreochromis niloticus) in the Daegu Metropolitan City thermal effluent stream (Dalseo Stream) from January to November 2019. The collected fish were identified as 4,247 individuals of 20 species from a total of eight families. The dominant species was O. niloticus with 1,306 individuals and a high relative abundance (30.75%). The water temperature of Dalseo Stream was maintained above 10℃ throughout the year, which means that O. niloticus could inhabit it even in winter. The length-weight analysis showed a regression coefficient b of 3.1496, and a condition factor (k) of 0.0025 with a positive slope. Comparing the water temperature of Dalseo Stream and the total length of O. niloticus per investigation period, the 0-age individuals appeared May 29 when the water temperature was maintained above 22℃. In conclusion, the thermal effluent of Dalseo Stream allowed O. niloticus to survive in winter and maintain stable growth conditions and life cycles. The results of this study will inform ecological information on O. niloticus, which suggests that river management efforts should consider the management of O. niloticus populations for the conservation of fish species diversity.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.39 no.1
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• pp.37-42
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• 2021

Munseom (Island) is known as the largest native Elaeocarpus sylvestris var. ellipticus in Korea. Recently, disease damage from the E. sylvestris var. ellipticus community has been reported in Munseom. This study was conducted to understand the damage situation and growth characteristics of the E. sylvestris var. ellipticus population in Munseom. The purpose of this study was to evaluate the spontaneous regeneration potential of the community by grasping the characteristics of the population of surviving E. sylvestris var. ellipticus individuals, and to discuss ways to restore native habitats. A total population survey was conducted to determine the distribution status of E. sylvestris var. ellipticus individuals. The field survey carefully recorded the height of tree, DBH, DRH, and growing status, along with GPS location information of the individual. The growth status of E. sylvestris var. ellipticus individuals distributed in Munseom and the characteristics of tree height, DBH, DRH of each individual were analyzed. The total number of E. sylvestris var. ellipticus populations identified in Munseom was 293. The dense E. sylvestris var. ellipticus community reported in 2005 has been identified as being greatly damaged or damaged. In particular, the damage was more serious in mature trees with a height of 6m or more forming the canopy layer in the forest, and it was confirmed that 80.6% of the mature trees died. In the growth characteristics of the old-growth tree, which is an indicator of the health of the forest based on DRH, 75.4% died or the growth condition was found to be poor. In order to restore the native habitat of E. sylvestris var. ellipticus in Munseom, conservation efforts such as pest control, preservation of mature trees, control of the territory of young trees, and reintroduction after ex-situ transplantation etc. are considered necessary.

• Korean Journal of Ecology and Environment
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• v.57 no.1
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• pp.39-50
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• 2024

In ecosystems within limited resources, interspecific competition is inevitable, often leading to the competitive exclusion of inferior species. This study aims to provide foundational information for the conservation and restoration management of Microphysogobio rapidus by evaluating species' ecological response to biological factors within its habitat. To understand this relationship, we collected food web organisms from site where M. rapidus coexist with Microphysogobio yaluensis, a specie ecologically similar to M. rapidus, and evaluated the trophic levels (TL), isotopic niche space (INS), and the overlap of INS among fishes within the habitat using stable isotope analysis. Our analysis revealed that the M. rapidus exhibited a higher TL than M. yaluensis, with TL of 2.6 and 2.4, respectively. M. yaluensis exhibited a broad INS, significantly influencing the feeding characteristics of most fish. Conversely, M. rapidus showed a narrow INS and asymmetric feeding relationships with other species, in habitats with high competition levels. This feeding characteristics of M. rapidus indicate that the increase in competitors sharing the similar resources lead to a decrease in available resources and, consequently, is expected to result in a decrease in their density.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.5
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• pp.278-284
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• 2014

Water temperature due to climate change can be estimated using the air temperature because the air and water temperatures are closely related and the water temperatures have been widely used as the indicators of the environmental and ecological changes. It is highly necessary to estimate the frequency distribution of the air and water temperatures, for the climate change derives the change of the coastal water temperatures. In this study, the distribution function of the air temperatures is estimated by using the long-term coastal air temperature data sets in Korea. The candidate distribution function is the bi-modal distribution function used in the previous studies, such as Cho et al.(2003) on tidal elevation data and Jeong et al.(2013) on the coastal water temperature data. The parameters of the function are optimally estimated based on the least square method. It shows that the optimal parameters are highly correlated to the basic statistical informations, such as mean, standard deviation, and skewness coefficient. The RMS error of the parameter estimation using statistical information ranges is about 5 %. In addition, the bimodal distribution fits good to the overall frequency pattern of the air temperature. However, it can be regarded as the limitations that the distribution shows some mismatch with the rapid decreasing pattern in the high-temperature region and the some small peaks.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.5
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• pp.285-291
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• 2014

The statistical information of the coastal water temperature monitoring data can be biased because of outliers and missing intervals. Though a number of outlier detection methods have been developed, their applications are very limited to the in-situ monitoring data because of the assumptions of the a prior information of the outliers and no-missing condition, and the excessive computational time for some methods. In this study, the practical robust method is developed that can be efficiently and effectively detect the outliers in case of the big-data. This model is composed of these two parts, one part is the construction part of the approximate components of the monitoring data using the robust smoothing and data re-sampling method, and the other part is the main iterative outlier detection part using the detailed components of the data estimated by the approximate components. This model is tested using the two-years 5-minute interval water temperature data in Lake Saemangeum. It can be estimated that the outlier proportion of the data is about 1.6-3.7%. It shows that most of the outliers in the data are detected and removed with satisfaction by the model. In order to effectively detect and remove the outliers, the outlier detection using the long-span smoothing should be applied earlier than that using the short-span smoothing.

• Asian Journal of Atmospheric Environment
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• v.8 no.3
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• pp.162-174
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• 2014

An abnormal decrease in ozonesonde sensor signal occurred during air-pollution study campaigns in November 2011 and March 2012 in Mexico City Metropolitan Area (MCMA). Sharp drops in sensor signal around 5 km above sea level and above were observed in November 2011, and a reduction of signal over a broad range of altitude was observed in the convective boundary layer in March 2012. Circumstantial evidence indicated that $SO_2$ gas interfered with the electrochemical concentration cell (ECC) ozone sensors in the ozonesonde and that this interference was the cause of the reduced sensor signal output. The sharp drops in November 2011 were attributed to the $SO_2$ plume from Popocat$\acute{e}$petl volcano southeast of MCMA. Experiments on the response of the ECC sensor to representative atmospheric trace gases showed that only $SO_2$ could cause the observed abrupt drops in sensor signal. The vertical profile of the plume reproduced by a Lagrangian particle diffusion simulation supported this finding. A near-ground reduction in the sensor signal in March 2012 was attributed to an $SO_2$ plume from the Tula industrial complex north-west of MCMA. Before and at the time of ozonesonde launch, intermittent high $SO_2$ concentrations were recorded at ground-level monitoring stations north of MCMA. The difference between the $O_3$ concentration measured by the ozonesonde and that recorded by a UV-based $O_3$ monitor was consistent with the $SO_2$ concentration recorded by a UV-based monitor on the ground. The vertical profiles of the plumes estimated by Lagrangian particle diffusion simulation agreed fairly well with the observed profile. Statistical analysis of the wind field in MCMA revealed that the effect Popocat$\acute{e}$petl was most likely to have occurred from June to October, whereas the effect of the industries north of MCMA, including the Tula complex, was predicted to occur throughout the year.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.4
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• pp.47-52
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• 2014

Species distribution models have been widely applied in order to assess biodiversity, design reserve, manage habitat and predict climate change. However, SDMs has been used restrictively to the public and policy sectors owing to model uncertainty. Recent studies on ensemble and consensus models have been increased to reduce model uncertainty. This paper was carried out single model and multi model for Corylopsis coreana and compares two models. First, model evaluation was used AUC, kappa and TSS. TSS was the most effective method because it was easy to compare several models and convert binary maps. Second, both single and ensemble model show good performance and RF, Maxent and GBM was evaluated higher, GAM and SRE was evaluated lower relatively. Third, ensemble model tended to overestimate over single model. This problem can be solved by the suitable model selection and weighting through collaboration between field experts and modeler. Finally, we should identify causes and magnitude of model uncertainty and improve data quality and model methods in order to apply special decision-making support system and conservation planning, and when we make policy decisions using SDMs, we should recognize uncertainty and risk.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.5
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• pp.311-316
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• 2013

In this study, the wave energy potential (WEP) was evaluated using the wave data measured at nine stations along the Korean east coast and compared with the results of previous studies. Along the Korean east coast, seasonal variations in the WEP were around 6.4 kW/m in winter and 1.2 kW/m in summer, greater than spatial variations of 2.5~4.3 kW/m. In most stations, the wave power during June to July were shown to be smallest. The estimated annual average WEP was greatest in the Mukho and Jukbyeon stations located in the middle of the Korean east coast at around 4.3 kW/m, and smallest in the Jinha station at around 2.5 kW/m. The results found using the previous hindcast data showed WEP having a tendency to decrease from south to north. However, in this study, the WEP showed a tendency of being greatest in the middle of the Korean east coast and decreasing in both north and south directions.

• Korean Journal of Ichthyology
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• v.32 no.3
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• pp.130-135
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• 2020

Male gonadal development of the yellow catfish, Pseudobagrus fulvidraco, one of the most popular fish species in Korean aquaculture performance, was investigated by histological observation of monthly collected specimens to make comparisons between wild and cultured individuals. Their reproductive cycle was classified into the successive developmental stages as follows: a growing stage (April), a spawning stage (May), a degeneration stage (June to July), and a resting stage (August to October) in the wild and outdoor-cage individuals; a growing stage (April to June), a spawning stage (July to August), a degeneration stage (September), and a resting stage (October) in the indoor-cage ones. Values of gonadosomatic index (GSI) of wild and outdoor cages peaked in May, followed by a sudden decline in August~September and June~August, respectively. In contrast, GSI values of the indoor-cage individuals peaked in September and were followed by a sudden drop. Remarkable seasonal variation in condition factor (CF) was undetectable, peaking in June in the wild-cage individuals and November in the wild ones. Overall, our results suggest that it is suitable to use the male of the outdoor-cage individuals for artificial fertilization and that it is efficient to perform artificial fertilization in May, such as reproductive cycle of wild.