• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.4
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• pp.527-536
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• 2022

The purpose of this study is to predict changing traffic environments and related economic effects by reflecting the changed KTDB and socio-economic indicators pertaining to Mulgeum station, a general railway stop, when it is confirmed as a KTX stop. To analyze the data of this study, socioeconomic indicators and the general status of transportation facility operations were investigated with reference to related statistical data, centered on the country overall and on Yangsan city in particular. In addition, we investigated and referenced the railroad facility construction plan and train operation plan, which are national high-level plans related to land development and transportation network construction. Currently, there are only ITX trains (4 times/day) and Mugunghwa trains (29 times/day) that stop at Mulgeum station in Yangsan, meaning that passengers cannot use KTX trains in the Yangsan area. In particular, the need for a KTX stop at Mulgeum station has been continuously raised because train users in the Yangsan area have inconvenient transportation in that they must travel 40 minutes to Ulsan station or 30 minutes to Gupo station to use the KTX. As a result of analyzing railroad transportation demand that will change in the future as the KTX stop at Mulgeum station is confirmed, the number of passengers boarding and arriving at Mulgeum station is predicted to be 1,674 passengers/day by 2025. In addition, the numbers of train passengers that are converted from Ulsan and Gupo stations due to the stop at Mulgeum station are predicted to be 594 passengers/day boarding and 562 passengers/day arriving by 2025. In the future, if Yangsan citizens use the KTX Mulgeum station, the access time to Mulgeum station can be shortened to 22 minutes from 65 minutes, and it is predicted that the inconvenience of transferring between railroads will be resolved, with the waiting time for transfers reduced by up to a maximum of 40 minutes. Therefore, the economic effect of creating a KTX stop at Mulgeum station was analyzed to be B/C=1.823 when general railroad operating costs are not taken into account and B/C=2.127 when general railroad operating costs are considered. In conclusion, when using KTX trains to visit the Seoul Metropolitan Area, it takes 2 hours and 43 minutes to use Mulgeum station without using Ulsan station or Gupo station, which is considered to be very effective for reducing travel times and improving the economic feasibility of this development; it is also expected that Yangsan city will be able to improve accessibility and mobility to the Seoul Metropolitan Area by breaking free from the disgrace of being a remote location given its link to KTX in the future.

• Journal of Korean Society on Water Environment
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• v.25 no.6
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• pp.832-839
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• 2009

Since construction of the estuarine barrage at the mouth of the Nakdong River, eutrophication and increased abundance of phytoplankton have occurred mainly due to the increased retention time in the reach. However, during the spring, there is a decrease in chlorophyll-a, as a result of an increase in zooplankton number, which preys upon phytoplankton and affects the value of chlorophyll-a. In order to emphasize the importance of zooplankton data in water quality simulation, zooplankton community data were used to simulate water quality and eutrophication at Mulgeum located in 27 km upstream from the barrage. WASP 7.2 was used as the water quality model for the river, using a monthly data set from 2003 to 2005 for model calibration and verification. The results showed that chlorophyll-a, DO, and total nitrogen in the river were simulated well during the verification period. The results of water quality simulation using zooplankton community data in the model were better than those with phytoplankton death rate, in terms of the absolute value of percent bias, root mean square error, and Nash-Sutcliffe efficiency. Those results indicate the use of zooplankton data provides more accurate simulation results for chlorophyll-a and eutrophication.

• Proceedings of the Korean Geotechical Society Conference
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• 1996.10a
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• pp.257-266
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• 1996

• Journal of Environmental Science International
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• v.25 no.3
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• pp.361-371
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• 2016

Ministry of Environment has been operating water quality monitoring network in order to obtain the basic data for the water environment policies and comprehensively understand the water quality status of public water bodies such as rivers and lakes. The observed water quality data is very important to analyze by applying statistical methods because there are seasonal fluctuations. Typically, monthly water quality data has to analyze that the transition comprise a periodicity since the change has the periodicity according to the change of seasons. In this study, trends, SOM and RDA analysis were performed at the Mulgeum station using water quality data for temperature, BOD, COD, pH, SS, T-N, T-P, Chl-a and Colon-bacterium observed from 1989 to 2013 in the Nakdong River. As a result of trends, SOM and RDA, the Mulgeum station was found that the water quality is improved, but caution is required in order to ensure safe water supply because concentrations in water quality were higher in the early spring(1~3 month) the most.

• Korean Journal of Medicinal Crop Science
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• v.20 no.6
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• pp.421-433
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• 2012

This study was carried out to survey the vascular plants in 6 regions including around Hopo-Bridge of Yangsan region at waterfronts of Nakdong river, Korea. Distributed plants were surveyed from April to November, 2011. The vascular plants in 6 regions (around Mulgeum-chuisujang, Mulgeum-station, Jeungsan-ri, Hopo-bridge, Kumoh-bridge and lower part of Yangsan-stream) were total 135 taxa of 3 divisions, 4 classes, 37 orders, 66 families, 116 genera, 114 species, 2 subspecies and 19 varieties. The most number of species is Campanulales of 14.1% in Dicotyledoneae of 81.5% among total species. Regional distribution of species is mainly around Mulgeum-chuisujang and Jeungsan-ri as 61% among total species, and other regions is in 24 ~ 44%. Ecologically, there were herbaceous plants 75% and woody plants 25%, and 9 species of aquatic plants in herbaceous plants. Medicinal (herbal) plants included in KP (The Korean Pharmacopoeia) and KHP (The Korean Herbal Pharmacopoeia) were 56 species including Platycodon grandiflorum (Jacq.) A. De Candolle, Peucedanum japonicum Thunberg and etc., and folk herb plants were 14 species including Metaplexis japonica Makino, Commelina communis Linn$\acute{e}$ and etc. among total 135 species.

• Journal of Life Science
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• v.33 no.10
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• pp.783-790
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• 2023

Modern people have an increased incidence of metabolic diseases due to changed eating habits, and diabetes is considered the most significant metabolic disease. Given that existing diabetes treatments are accompanied by side effects, the aim of this study was to identify traditional natural products that have anti-diabetic activity. The potential anti-diabetic and antioxidant activities of natural products were examined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay, α-glucosidase assay, and protein tyrosine phosphatase 1B (PTP1B) inhibition assay. Methanol extracts of Ulmus davidiana var. japonica, Acer tegmentosum branches, Nelumbo nucifera seeds, and Carthamus tinctorius seeds were found to have high anti-diabetic activity and further fractionated with solvents using ethyl acetate and butanol. Consequently, the ethyl acetate fraction of C. tinctorius seeds (MG-11-E) with high α-glucosidase and PTP1B inhibitory activity was selected. MG-11-E was subjected to preparative thin layer chromatography, and fraction #6 showed high α-glucosidase and PTP1B inhibitory activity. Fraction #6 was analyzed and fractionated via high performance liquid chromatography with 50% methanol as the mobile phase, and anti-diabetic activity was observed in the sample that eluted after 4 min as a single peak. The α-glucosidase inhibitory activity exhibited by this sample seemed to be greater than the PTP1B inhibitory activity; thus, it was concluded that a greater anti-diabetic therapeutic effect may be achieved by combining this agent with natural products that inhibit PTP1B activity.

• Journal of the Mineralogical Society of Korea
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• v.25 no.4
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• pp.305-312
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• 2012

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.4
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• pp.467-487
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• 2013

Long-term and systematic monitoring of phytoplankton is important, as phytoplankton serve as indicators of water quality status in aquatic environments. In the present study, the plankton community structure of the Nakdong River estuary over the past 30 years was investigated by literature survey to provide references for the occurrence of planktonic species. A total of 876 species from 18 taxonomic lineages were reported and, among them, 569 species were identified to occur seasonally at the Mulgeum, Seonam and Eulsukdo sites. Diatoms and chlorophytes were dominant in the microscopic studies. The 54 species at the Mulgeum and the 96 species at the Eulsukdo sites have not been reported since the river barrage construction in 1987. The majority of reports speculate that there has been a change in the aquatic environment, particularly the plankton community structure, due to operation of a river barrage since 1987.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.3
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• pp.103-108
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• 1980

The contents of inorganic conservative constituents in Nagdong River water were determined at Mulgeum where the intake station for Busan city water is located. Samples were taken at intervals of one hour from 7 a.m. to 7 p.m. at spring and neap tides of every month from January 1979 to April 1980. Annual ranges and means of the chemical constituents were as follows: electrical conductivity $99-912\mu\mho/cm,\;200\mu\mho/cm;$ chlorides 6.0-256 ppm, 17.2 ppm; sulfates 4.1-37.9 ppm, 23.5 ppm; calcium 4.2-28 ppm, 13 ppm; magnesium 2.2-23 ppm, 5.6 ppm; sodium 5,0-126 ppm, 14 ppm; and potassium 1.2-10.8 ppm, 2.6 ppm respectively. At several times in this period, the concentrations of chloride ion exceeded 150 ppm that is the criteria for drinking water. The chloride ion concentration was higher at spring tides than that at neap tides and the contents of inorganic conservative constituents were higher in winter than those in summer. The chloride ion concentration showed the highest value at Mulgeum about 4 hors after the high water in Busan harbour.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.123-130
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• 1999

This paper presents a study of geotechnical treatment for artesian pressure after extensive investigation was performed on the distribution and characteristics of artesian condition which exists at Yangsan/Mulgeurn site. The result of analysis indicates that the artesian pressure seems to be up to 2.9M above the existing ground surface, originating from the higher ground water recharging sources in the surrounding hills and mountains. There is no harmful effect after the site development since the height of embankment is more than 4M above the existing ground surface.