• Journal of Digital Convergence
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• v.19 no.10
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• pp.253-263
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• 2021

Machine learning is the process of constructing a cost function using learning data used for learning and an artificial neural network to predict the data, and finding parameters that minimize the cost function. Parameters are changed by using the gradient-based method of the cost function. The more complex the digital signal and the more complex the problem to be learned, the more complex and deeper the structure of the artificial neural network. Such a complex and deep neural network structure can cause over-fitting problems. In order to avoid over-fitting, a weight decay regularization method of parameters is used. We additionally use the value of the cost function in this method. In this way, the accuracy of machine learning is improved, and the superiority is confirmed through numerical experiments. These results derive accurate values for a wide range of artificial intelligence data through machine learning.

• Journal of the Korea Convergence Society
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• v.10 no.3
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• pp.193-201
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• 2019

The public's interest regarding multi-household houses, one of the small-scale housings used as profit earning property, has been increasing. Previous studies regarding price, such as the rent and sales price of multi-household houses', however, were difficult to find. Thus, this study set forth to find out what characteristics influence the sales price of multi-household houses so as to provide further suggestions to investors' decision makings and developers' strategy establishments. The data was retrieved from multi-household sales transacted in Changwon City. Through empirical analysis, this paper found that prices were high in Euichang-gu and Seongsan-gu, and meaningful variables in terms of locations were distance from major trade areas(-), distance from main streets(-), and Corner site(+). Meaningful variables related to household characteristics were total floor area(+), Studio type(+), Southern exposure(+), Building age(-), and Full-furnished(+).

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.1
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• pp.39-50
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• 2022

In this study, we suggested the optimal training period for predicting the streamflow using the LSTM (Long Short-Term Memory) model based on the deep learning and CMIP5 (The fifth phase of the Couple Model Intercomparison Project) future climate scenarios. To validate the model performance of LSTM, the Jinan-gun (Seongsan-ri) site was selected in this study. We comfirmed that the LSTM-based streamflow was highly comparable to the measurements during the calibration (2000 to 2002/2014 to 2015) and validation (2003 to 2005/2016 to 2017) periods. Additionally, we compared the LSTM-based streamflow to the SWAT-based output during the calibration (2000~2015) and validation (2016~2019) periods. The results supported that the LSTM model also performed well in simulating streamflow during the long-term period, although small uncertainties exist. Then the SWAT-based daily streamflow was forecasted using the CMIP5 climate scenario forcing data in 2011~2100. We tested and determined the optimal training period for the LSTM model by comparing the LSTM-/SWAT-based streamflow with various scenarios. Note that the SWAT-based streamflow values were assumed as the observation because of no measurements in future (2011~2100). Our results showed that the LSTM-based streamflow was similar to the SWAT-based streamflow when the training data over the 30 years were used. These findings indicated that training periods more than 30 years were required to obtain LSTM-based reliable streamflow forecasts using climate change scenarios.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.4
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• pp.287-296
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• 2002

A field trial was conducted from May to November 2000 at four regions of Jeju province(Jeju, Seogwipo, Susan Seongsan and Keumak Hallim) to estimate adaptation, dry matter yield and nutrient value of kenafs(Everglades 41 and China Choung-pi 3) and a sorghum-sudangrass hybrid(Pioneer 947). Total dry matter(DM) yields of sorghum-sudangrass hybrid Pioneer 947, kenaf Everglades 41 and kenaf China Chong-pi 3 were 7,313, 4,653 and 5,238 kg/ha(P<0.05), respectively, kenaf China Chong-pi 3 being the highest. The region specific dry matter(DM) yields of Jeju, Seogwipo, Seongsan and Hallim area were 5,040, 5,663, 7,283 and 4,950kg/ha, respectively, showing that Seogwipo was the highest. Average DM yields of two kenaf varieties were 4,946, and 3,246 kg/ha for 1st time-cutting and 2nd time-cutting, respectively. The average dry matter(DM) yield of kenaf was significantly higher in the 1st time-cutting than the 2nd time. No significant difference in neutral detergent fiber(NDF) and acid detergent fiber(ADF) contents was found among three varieties. The average crude protein(CP) content of kenaf was higher than that of sorghum-sudangrass hybrid(P<0.05) and was higher in 2nd time-cutting than in 1st time-cutting(P<0.05). There were no significant difference in the heavy metal content of soil either between the sorghum hybrid and kenafs or between two kenaf varieties. In conclusion, the average dry matter(DM) yield of kenaf was lower than that of sorghum hybrid, Contrarily the crude protein(CP) content of kenafs was higher than that of the sorghum hybrid. The average dry matter(DM) yield of kenaf showed higher in 1st time-cutting than 2nd time-cutting, while the crude protein(CP) content of kenafs decreased with time.

• Economic and Environmental Geology
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• v.44 no.2
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• pp.95-107
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• 2011

The Hwangsan volcanic rocks, hosting the Moisan epithermal Au-Ag deposit arc widely distributed throughout the Seongsan district, and associated with large hydrothermal alteration. They were analyzed as the Moisan and around voleanic rocks, and most of them show dacitic to rhyolitic compositions. Hydrothermal alteration related to epithermal system causes the host rocks to show the geochemical variation due to high mobility of alkali elements. These features can be applied for quantitative estimates of alteration intensity. Alteration intensity of volcanic rocks from the Moisan ranges from subtle to intense, based on AI vs. $Na_2O$ diagram. The pattern that ($CaO+Na_2O$) content decrease with increasing $K_2O$ content results from sericitic alteration, in which hydrothermal fluids continually provide $K^+$ into country rocks but remove $Ca^{2+}$ and $Na^{2+}$ of feldspars within country rocks. The decrease of ($CaO+Na_2O$) with decreasing $K_2O$ in some samples from the Moisan may be caused by advanced argillic alteration that all alkali elements are entirely removed from country rocks by acid hydrothermal fluids. Two alteration trends, based on Al and CCPI alteration indices suggest both sericitic alterations of feldsaprs to illite and sericite+chlorite$^{\circ}{\ae}$pyritc alteration of high Mg and Fe activities. Trace and Rare Earth Elements patterns show the similar geochemical variation related to hydrothermal alteration. Of LIL elements, strong depletion of $Sr^{2+}$, substituting for $Ca^{2+}$ in feldspars, appears to be resulted from removal of $Ca^{2+}$, during replacement of feldspars to alumino-silicates or phyllo silicates minerals by hydrothermal fluids. Relatively low total REEs contents (Moisan: 119-182 ppm; Seongsan: 111-209 ppm) and gently negative slopes suggest that significant mobility of LREEs appear to occur during hydrothermal alteration.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.2 no.1
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• pp.47-62
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• 1969

A goby, Synechogobius hasta (Temminck et Schlegel) was studied to investigate the food consumed and the biological change of the food organisms, and the fish were sampled from the closed tributary and the lower Part of the Naktong River, near Pusan, during the period from November of 1967 to December of 1968. The fish were sampled from four stations (Fig. 1), the total number of fish being 1,295 and they were grouped and analysed monthly. The content of the alimentary canal was analysed in three categories according to modified Nilsson's method (Dahl 1962) with a slight alteration: 1) The number of each item of stomach contents was counted and the percentage of each item in proportion to the total number of food organisms is indicated by the letter 'N' representing numerical percentage in Table 2. 2) The percentage of fish which contained any items of food organisms in proportion to the total number of fish caught in a given season is indicated by the letter 'O' representing frequency of occurrence. 3) Dominant groups of food items were selected and the percentage of the number of each dominant item in proportion to the number of the food organisms belonging to the dominant groups is indicated by the letter 'D' representing dominance. All food organisms were classified in 50 food item categories and then they were grouped in 13 main groups (Fig. 2-1), and they were further divided into 1) obligatory bottom animals, 2) organic drifts and 3) actively swimming forms; according to the conditions of the animal communities within the habitat. Since the majority of its food was composed of the obligatory bottom animals ($94.6\%$), the fish appeard to be a typical bottom feeder. And the dominant food organisms of the fish is generally determined by the local composition of the benthic fauna within the fish habitat. And their seasonal rhythm occurs among the food organisms in the stomach by the biological interaction. Locality variation in the population of the same food organism occurs due to the difference of food organisms in the habitat of the fish at Seonam and Garak, and at Seongsan and Hadan the condition of the niche for the fish in the both regions seems to be the same since the composition and the seasonal variation of the organisms were the same. The results may be summarized as follows: 1) The goby mainly feed on the animals of bottom fauna, and the food organisms are deter-mined by the food compositions within the habitat. 2) Seasonal variation of the stomach content shows the seasonal rhythm due to the biological variation of the population and their interaction. 3) The goby shows no preference on specific food, and the food is composed of a variety of animals. 4) Major food items of the goby are Polychaeta, Palaemon modestus, Isopoda, Gammaridea, Insecta (nymphs and larvae), Ilyoplax deschampsi, and Paratye compressa. 5) Logitudinal succession oil the population of the food organisms is apparently recognized within the community of Seongsan, Garak and Seonam. 6) The goby begins to descend toward the estuary and sea around April when the water temperature reaches $20^{\circ}C$, and they begin to return to river waters in September.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.3
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• pp.64-75
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• 2014

The purpose of this study is to analyze the effects of satisfaction in neighborhood park environments located in the Changwon-si of Gyeongsangnam-do, South Korea, on physical activity, the number of parks used for health improvement, and health levels based on Body Mass Index(BMI). Accordingly, a survey was conducted of 429 nearby residents and users of eight neighborhood parks located in urban areas of Seongsan-gu and Uichang-gu in the Changwon-si. The correlation between the environmental perception of neighborhood parks and physical activity and health, which was observed in the survey results, was analyzed using one-by-one linear regression analysis. By summarizing the study results, it was found that the primary reasons for avoiding park use were lack of time, time and effort required to reach the park(i.e., distance from the park), and lack of facilities within the park. Conversely, the primary reasons for using the park included accessibility, walking or strolling, leisure facilities, trees or shade, and diversity in exercise areas. In the case of park users, walking or strolling was the most common activity in the park. On average, park users walked to the parks for 10 minutes and exercised for an hour at least twice per week. With respect to the physical environment of the parks and surrounding areas, park users showed a high level of satisfaction with the distance between their houses and parks and the street environment. On the contrary, they exhibited low levels of satisfaction with water spaces and sightseeing within the parks. Subsequently, it was shown that the number of people using the parks for physical activities and health improvement was positively influenced(within a 5% significance level) by the intent to use the park for exercise, time spent in the park, satisfaction with park use and health improvement, distance to the park, and the convenience of using the park for the elderly. However, only the health improvement gained from park use was found to exhibit a correlation with BMI at the 10% significance level. Continuous accumulation of practical case studies on physical activities in parks and their health improvement effects is required. Through this, park spaces that are under the threat of reduction or elimination owing to various development plans can be conserved and expanded. Furthermore, such case studies can be used to provide data as the basis for deriving park plans and designs that improve parks' functions as sites of physical activity and health improvement.

• Korean Journal of Environmental Biology
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• v.38 no.2
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• pp.299-307
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• 2020

This study reported on the phytoplankton community and seasonal changes in the Seoul passage section and downstream in the Han River in 2012. Field samples were collected monthly from the upper (Paldang), middle (Cheongdam), and downstream(Seongsan) areas of the Seoul passage section. Water temperature, DO, pH, and conductivity were measured at each station. All environmental factors measured were recorded similarly at the three stations. The water temperature ranged from 2 to 30℃ and the dissolved oxygen ranged from 4.8 to 9.1 mg L^-1, showing typical patterns of temperate regions. The phytoplankton cell concentrations ranged from 990 cells mL^-1 (Paldang, December) to 2.9×10⁴ cells mL^-1 (Seongsan, March), and the chlorophyll-a content showed similar patterns to the cell numbers. The phytoplankton community was comprised of 75 genera and 95 species, including 37 diatoms, 29 Chlorophyta, 11 cyanobacteria, and two dinoflagellates. The number of species that appeared seasonally varied greatly, from nine species (Paldang, May) to 35 species (Cheongdam, December). Diatoms were the most dominant in all stations and seasons, except in summer. In contrast, chlorophytes and cyanobacteria showed sporadic high numbers in the summer and fall seasons. Four diatoms Stephanodiscus hantzschii f. tenuis, S. hantzschii, Fragilaria sp., and Aulacoseira spp., a chlorophyte Actinastrum hantzschii, and a cyanobacterium Microcystis sp. were each present in proportions greater than 10%. This study provides fundamental data from phytoplankton communities and environmental factors in the Han River for understanding water quality for long-term environmental monitoring.

• The Journal of Engineering Geology
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• v.33 no.1
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• pp.105-119
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• 2023

Water supply is decreasing due to climate change, and coastal and island regions are highly dependent on groundwater, reducing the amount of available water. For sustainable water supply in coastal and island regions, it is necessary to accurately diagnose the current condition and efficiently distribute and manage water. For a precise analysis of the groundwater flow in the coastal island region, submarine fresh groundwater discharge was calculated for the Seongsan basin in the eastern part of Jeju Island. Two methods were used to estimate the thickness of the fresh groundwater. One method employed vertical interpolation of measured electrical conductivity in a multi depth monitoring well; the other used theoretical Ghyben-Herzberg ratio. The value using the Ghyben-Herzberg ratio makes it impossible to accurately estimate the changing salt-saltwater interface, and the value analyzed by electrical conductivity can represent the current state of the freshwater-saltwater interface. Observed parameter was distributed on a virtual grid. The average of submarine fresh groundwater discharge fluxes for the virtual grid was determined as the watershed's representative flux. The submarine fresh groundwater discharge and flux distribution by year were also calculated at the basin scale. The method using electrical conductivity estimated the submarine fresh groundwater discharge from 2018 to 2020 to be 6.27 × 10⁶ m³/year; the method using the Ghyben-Herzberg ratio estimated a discharge of 10.87 × 10⁶ m³/year. The results presented in this study can be used as basis data for policies that determine sustainable water supply by using precise water budget analysis in coastal and island areas.

• Korean Journal of Environment and Ecology
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• v.28 no.3
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• pp.281-286
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• 2014

This study was conducted to investigate the individual size and age of Kaloula borealis, a pair in amplexus. In June 2013, the total 23 pairs of Kaloula borealis were captured in the wetland located in Seongsan-eup and Daejeong-eup, Jeju Island. Size and age of each individual have been examined and as a result of analyzing SVL (snout-vent length), weight, length of forelimb and hindlimb of the collected 23 pairs, the females were shown to have the heavier weight and the longer SVL and hindlimb compared to males. No significant difference in the length of forelimb has been found between the female and the male. The average age of the male of the pair in amplexus was shown to be $5.17{\pm}0.26$, whereas the female was shown to be $6.22{\pm}0.28$, which indicates the higher average age in female compared to the male. The age range of Kaloula borealis was distributed from at least 3 years to 10 years at the maximum. A positive correlation was shown between age of the male and SVL; however, no significant difference was found in female. This study result expected to be utilized as an important base data in establishing the preservation and restoration strategy of endangered species, Kaloula borealis.