• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.55 no.5
• /
• pp.514-523
• /
• 2022

Concentrations of perfluoroalkyl substances (PFASs) were measured in seawater, sediment, and biota collected from Gunsan coast, Korea to investigate their occurrence, distribution, and risk of exposure to humans through seafood consumption. The total concentrations of PFASs in seawater, sediment, and biota ranged from 5.97 to 74.9 ng/L, 0.01 to 13.3 ng/g dry weight, and 0.02 to 5.73 ng/g wet weight, respectively. Predominant PFAS compounds differed across matrices, indicating that the distribution of PFASs in multiple environmental samples is governed by their carbon-chain length. The concentrations of PFASs in seawater were significantly negatively correlated with salinity (P<0.01), suggesting terrestrial input (including land-used PFASs) as the major source of PFAS contamination in coastal environments. The estimated daily intakes (EDIs) of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) through seafood consumption were 0.05 and 0.06 ng/kg body weight/day, respectively. The EDIs of PFOA and PFOS measured in this study were lower those the proposed by the United States Environmental Protection Agency and Canada guidelines, indicating limited health risk for Korean population from PFASs through consumption of seafood from Gunsan coastal environment.

• Journal of Information Technology Services
• /
• v.21 no.3
• /
• pp.63-72
• /
• 2022

The extinction crisis of local cities, caused by a population density increase phenomenon in capital regions, directly causes the increase of vacant houses in local cities. According to population and housing census, Gunsan-si has continuously shown increasing trend of vacant houses during 2015 to 2019. In particular, since Gunsan-si is the city which suffers from doughnut effect and industrial decline, problems regrading to vacant house seems to exacerbate. This study aims to provide a foundation of a system which can predict and deal with the building that has high risk of becoming vacant house through implementing a data driven vacant house prediction machine learning model. Methodologically, this study analyzes three types of machine learning model by differing the data components. First model is trained based on building register, individual declared land value, house price and socioeconomic data and second model is trained with the same data as first model but with additional POI(Point of Interest) data. Finally, third model is trained with same data as the second model but with excluding water usage and electricity usage data. As a result, second model shows the best performance based on F1-score. Random Forest, Gradient Boosting Machine, XGBoost and LightGBM which are tree ensemble series, show the best performance as a whole. Additionally, the complexity of the model can be reduced through eliminating independent variables that have correlation coefficient between the variables and vacant house status lower than the 0.1 based on absolute value. Finally, this study suggests XGBoost and LightGBM based machine learning model, which can handle missing values, as final vacant house prediction model.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.15 no.4
• /
• pp.297-313
• /
• 2009

Long-term trends and distribution patterns of water quality were investigated in the Gunsan coastal areas of Yellow Sea, Korea from 1972 to 2006. Water samples were collected at 6 stations and physicochemical parameters were analyzed including water temperature, salinity, suspended solids(SS), chemical oxygen demand(COD), dissolved oxygen(DO) and nutrients. Spatial distribution patterns of temperature, DO and SS were not clear among stations but the seasonal variations were distinct except COD and SS. The trend analysis by principal component analysis(PCA) during 24 years revealed the significant variations in water quality in the study area. Spatial water qualities were clearly classified into 3 clusters by PCA; station cluster 1, 2~4, and 5~6. Annual water qualities were clearly classified into 4 surface water clusters and 5 bottom water clusters by PCA. By this multi-variate analysis. The annual trends were summarized as follows; Salinity, pH and DO tended to increase since late 1970's, COD to increase since 1987, and SS to decrease and nutrients to increase in Gunsan coastal waters due to the input of fresh water from land same as in Kyoungin coastal area, Asan coastal area and Choensoo bay.

• Journal of Korea Port Economic Association
• /
• v.24 no.4
• /
• pp.139-152
• /
• 2008

China's rapid growth of economy and developing logistics facilities such as sea and air ports can give the good effects to increase the trade and logistics cargo volumes within Pan Yellow Sea Economic Bloc which consists of Korea, China, Japan and Russia. These phenomenon also stimulate the development of the West Coastal Integrated Belt in South Korea. In the past 20th century, South Korea's advanced and developed areas were located on the Kyeong-Bu Axis, the straight line of Seoul and Busan. However, due to the china's effect, this axis is moving into the West Coast area between Incheon (Seoul) and Mokpo, which is closely located to China. In this aspect, sea ports located in West Coast of Korea have shown the steep increase in container and non-container cargo volumes. With regard to the changing environments in sea ports, this paper's aim is to investigate the developing potential of Gunsan (Saemangum) area located on mid of West Coast. As results, targeted area have shown the potential in terms of port network, supply chain management and transferring location for container cargoes. Moreover, for implementing the suitable roles, construction of New Saemangun port, closely located in Gunsan port, is needed to overcome the limitations of Gunsan port.

• Journal of Korean Society for Atmospheric Environment
• /
• v.25 no.6
• /
• pp.550-561
• /
• 2009

This study is to investigate the air pollution characteristics of an industrialized midsize west-coastal city by comparing air quality to a neighboring inland city. The hourly averaged data of $O_3$, $SO_2$, $NO_2$, CO, and $PM_{10}$ measured from continuous air quality monitoring sites in Gunsan (coastal) and Jeonju (inland) were analyzed. The data set covers the period from 2004 to 2006. The annual average concentrations of the air pollutants in two cities were compared in their abundances and temporal trends as well. $O_3$ and $SO_2$ in Gunsan were relatively higher than those in Jeonju, while vice versa in case of $NO_2$ and $PM_{10}$. It seems that heavy automobile emissions from Jeonju mainly bring on higher $NO_2$ and $PM_{10}$ than those in Gunsan on annual base. $NO_2$ concentrations in both cities showed bimodal diurnal variations with peaks in the morning and in the late evening. These peaks correspond to the coupled effects of rush hour traffic and meteorological conditions (i.e., variation of mixing height and dispersion conditions). Maximum hourly averages of $NO_2$ ranged from 18 ppb to 28 ppb at Jeonju, and from 12 ppb to 20 ppb at Gunsan. $O_3$ showed typical diurnal variation with a maximum in the afternoon between 14:00 and 16:00 LST. Diurnal variations of CO and $PM_{10}$ were similar to $NO_2$ while $SO_2$ was similar to $O_3$. Seasonal variations of $PM_{10}$ in both cities indicated that their concentrations during spring season were significantly high. Asian dust storms occur frequently during spring and seem to affect increase in $PM_{10}$. High $O_3$ and $PM_{10}$ days were selected from both cities. The analyses based on the HYSPLIT trajectory model during the high $O_3$ and $PM_{10}$ showed these episodes (six cases) were mostly coincident with Asian dust storm originated from northern China and Mongolia. However, these high air pollution episodes in the west coastal cities may not only be caused by the Asian dust but also affected by other air pollutants transported from China accompanying the Asian dust.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.15 no.1
• /
• pp.17-24
• /
• 2009

This study was conducted to find out the effects of relationship between ocean-meteorological factors and snowfall at Incheon, Gunsan and Mokpo when cold and dry continental air mass passed through the West Sea of Korea in winter. Mean snowfall from December to February showed the order of Gunsan (12.7 cm), Mokpo (9.0 cm) and Incheon (7.8 cm). In particular, the snowfall in the three regions showed the regional difference in December and February. It was well consistent with the extension of continental high. Extension of continental high can cause effect on snowfall at the west regions (Inchoen, Gunsan, Mokpo) of the Korean Peninsula. The continental high extended from the southern China to western coastal region of the Korean Peninsula in December, it extended from the northern China to central area of the Korean Peninsula in January. It also extended from the north side of China through Bohai Sea and Yodong Peninsula to central area of the Korean Peninsula in February. Therefore, more snowfall recorded in Incheon is higher in February than December whereas Gunsan and Mokpo is the opposite. The heavy snowfall at the three regions was caused by loss of the heat from the ocean to air when the heat loss was higher than 100 $W/m^2$. The heavy snowfall was also observed when the arrangement of continental high atmospheric pressure and low pressure was high at the west and low at the east, which formed a front in West and when the wind blow from the North or North West at the speed of 4${\sim}$8 m/sec.

• Economic and Environmental Geology
• /
• v.51 no.3
• /
• pp.233-248
• /
• 2018

Strata of the Central sub-basin in the Gunsan Basin, offshore, western Korea were analyzed by using integrated stratigraphy approach. As a result, five distinct unconformity-bounded units are recognized in the basin: Sequence I (Cretaceous or older(?)), Sequence II (Late Cretaceous), Sequence III (late Late Cretaceous or younger(?)), Sequence IV (Early Miocene or older(?)), Sequence V (Middle Miocene). Since the late Late Jurassic, along the Tan-Lu fault system wrench faults were developed and caused a series of small-scale strike-slip extensional basins. The sinistral movement of wrench faults continued until the Late Cretaceous forming a large-scale pull-apart basin. However, in the Early Tertiary, the orogenic event, called the Himalayan Orogeny, caused basin to be modified. From Late Eocene to Early Miocene, tectonic inversion accompanied by NW strike folds occurred in the East China. Therefore, the late Eocene to Oligocene was the main period of severe tectonic modification of the basin and Oligocene formation is hiatus. The rate of tectonic movements in Gunsan Basin slowed considerably. In that case, thermal subsidence up to the present has maintained with marine transgressions, which enable this area to change into the land part of the present basin.

• Journal of Korea Water Resources Association
• /
• v.46 no.5
• /
• pp.531-545
• /
• 2013

This paper was considered on the applicability of EFDC KUNSAN_SEDTRAN MODEL (2012) to calculate Gunsan Port sediment deposition height efficiently and to use for grasping its aspects quantitatively and providing its prevention measures reasonably based on well-known 3-dimensional EFDC sediment transport module. This model was calibrated and verified with various measured field data of A Report of Hydrological Variation on Kum River Estuary (2004). Due to the model calibration and relevant literature investigation for cohesive sediment parameters, settling velocity (WS), critical deposition stress (TD), reference surface erosion rate (RSE), critical erosion stress (TE) were identified as 2.2E-04m/s, 0.20 $N/m^2$, 0.003 $g/s{\cdot}m^2$, 0.40 $N/m^2$ respectivly on this model. In order to examine the applicability and precision of the model computation, the calculated model data of sediment deposition height at 13 stations for 71 days and suspended-sediment concentration at 2 stations, inner port and outer port for 15 days were compared and analyzed with the measured field data. As a result, the model applicability for sediment deposition height simulation was evaluated as NSE coefficient 0.86 and the precision for suspended-sediment concentration computation was evaluated as time averaged relative error (RE) 23%.

• Journal of Popular Narrative
• /
• v.27 no.3
• /
• pp.151-191
• /
• 2021

This paper examines what is the content of Gusan's urban identity, represented by the film and how the contents and aspects of this city's identity interact with the structure of the films' discourse. weaves Gunsan and Seoul into continuously reorganized cities based on an interactive relation, rather than literal ones. Seoul in which the time for a film narrative is closed is converted into the starting point for tour to Gunsan. The both points in which audiences' ex post return occurs are the starting point for the time for the film discourse and the other point in which the title is suggested. The journey-type of the narrative structure in this film is a3-dimensional spiral-shaped, rather than a 2-dimensional circular regression. embodies the characteristics and the identity and apriority of two cities, based on such a spiral-shaped temporal and spatial structure. Seoul severs the relation between grand narrative/collective memory and small narrative/individual memory as an agnostic one, in other words, it is a city that cuts off cities, relations and memory and rejects the continuity of memory. On the other hand, Gunsan is a city in which both grand and small narrative and collective and individual memory coexist and both split and isolated mind are cured and mutually consoled. It describes Gunsan as the surplus space as a being for others, while expressing its identity as robust and literal thing. The film describes it as the field in which oppositional concepts such as historical interruption and continuity and spatial being for others and originality become 3-dimensional spiral ones, through the reciprocity between the narrative and the discourse structure. This paper has an implication, in that it examines how temporal and spatial relationship constituting the urban identity interacts with the structure of the film narrative.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 2009.10a
• /
• pp.13-16
• /
• 2009