• Journal of Digital Convergence
• /
• v.19 no.2
• /
• pp.69-81
• /
• 2021

Coastal shipping performs a pivotal role as a national transportation network and is highly valuable in terms of enabling more economical transportation at affordable prices than road transportation. In this regard, this study aimed to examine changes in the characteristics and centrality of South Korea's costal shipping sea-route networks by analyzing the centrality of domestic coastal shipping. To this end, social network analysis was used as an analysis technique that enables an analysis on the characteristics of coastal shipping networks. As a result, Jeollanam-do showed the highest degree centrality, ranking first in both the in-degree and the out-degree. Jeollanam-do also exhibited the highest betweenness centrality, and Gangwon-do registered the highest closeness centrality. In terms of hub and authority centrality, Jeollanam-do topped the list, followed by Gyeongsangnam-do and Gangwon-do in order. Lastly, Jeollanam-do ranked highest in the hub index, followed by Incheon, other regions, and Gangwon-do in order. This study is significant for suggesting the cities and provinces that play a key role in coastal shipping each year and their corresponding items. Future studies are recommended to identify the trend of coastal shipping through more detailed research on each port by city and province.

• The Korean Journal of Ecology
• /
• v.16 no.1
• /
• pp.63-74
• /
• 1993

The ecotypic variation of Phragmites communis Trin. was studied from Aug. 1989 to March 1992 in three populations of salt marsh, estuary and fresh water areas of the western coastal regions in Korea. The length growth and aboveground total dry weight of Phragmites communis Trin. From three habitates were measured monthly and the seeds from them collected. Chlorophyll contents, bud number and width of Phragmites communis Trin. populations after their seeds were sown in seedbeds, and the growth of seedlings according to salt contents were also determined. The results lare summarized as follows: The height and basal diameter of shoot, leaf length and width, and total dry weight of Phragmites communis Trin. were very different from each other according to their natural habitats. The bud number of seeds was increased as sample sites moved from estuary to fresh water areas and salt marsh. The but the bud diameter turned out to be in reverse proportion to the bud number. The chlorophyll content of the population from fresh water was $8.6901{\mu}g/ml$, whereas that from estuary and salt marsh was $9.61801{\mu}g/ml$ and $10.3160{\mu}g/ml$, respectively. The average length growth and total dry weight of seedlings grown at different salt contents were compared. Those of fresh water area decreased at salt contents lower than 0.5% in culture solution and those of estuary at higher than 0.5%, but the population of salt marsh was shown to be capable of sustaining itself at 1.0%. All of these results suggested that the populations of Phragmites communis Trin. in the western coastal regions of Korea have undergone ecotypic variations: fresh water type, estuary type and salt marsh type.

• Journal of Environmental Health Sciences
• /
• v.24 no.3
• /
• pp.77-86
• /
• 1998

The concentrations of atmospheric dimethylsulfide (DMS) and the relevant environmental parameters were measured as part of the 3rd year project (August 1997-July 1998) to investigate the long range transport of atmospheric pollutants (LRTAP) between China and Korea. The main purpose of this study was to derive the contribution of natural sulfur emissions (represented by oceanic DMS fluxes) in estimating the total budgets of sulfur transported across the Yellow Sea. To this end, DMS concentrations were determined from the two western coastal monitoring sites (Cheju and Kang Hwa islands) during three field intensive experiments covering fall, winter, and spring seasons. From these series of experiments, we found that DMS concentrations of Cheju and Kang Iffwa were averaged at 74 $\pm$ 49.5 (range: 19~282 pptv (N=81)) and 63.7 $\pm$ 35.1 (range:25.8~131 pptv (N=19)), respectively. By combining these 3rd year data with those measured previously from the 2nd year, we were able to derive some general pictures of seasonal distribution patterns of DMS. Although DMS data were difficult to derive relationships with other parameters determined simultaneously, they were rarely exhibiting good correlations with temperature or wind speed. The oceanic flux of DMS for the western coastal regions of Korea, when estimated based on our data from two islands, was found on the range of 8.8~12.2 GgS/yr. By considering the relationship between DMS and non-seasalt sulfate, we could also provide rough estimate of relative significance of natural emissions of sulfur. If oceanic DMS emitted from those regions is entirely converted to sulfate, it could represent 10 to 25% of total sulfur budgets in the western Sea of Korea.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.15 no.4
• /
• pp.232-241
• /
• 2003

The interaction of incident monochromiatic waves with N bottom-mounted porous circular cylinders is investigated in the frame of three-dimensional linear potential theory. The fluid domain is divided into N+l regions i.e. a single exterior region and N interior regions, and the diffraction potential in each fluid region is expressed by an eigenfunction expansion method (Williams and Li,2000). The analytic results show that the porous structure reduces both the wave forces and the run-up wave around the cylinder. To verify the developed model, the systematic model test with a line array of porous cylinders is conducted at the wave tank (30m$\times$7m$\times$1.5m). The analytic results are in good agreement with the experimental results within measured frequency range. It is concluded that the breakwater constructed with an array of porous circular cylinders shows the performance of an effective wave barrier together with the seawater-exchange effect and is considered to have vast potentials for the use of seawater-exchanging breakwater in the future.

• Korean Journal of Medicinal Crop Science
• /
• v.11 no.3
• /
• pp.212-215
• /
• 2003

There were so many Asparagus cochinchinensis (Lour.) Merr. in the past in Korea. Now a day, it is under diminishing circumstance because of over exploitation for pharmacy materials. The amount of domestic market demand of it was imported. The autochthonous planting areas were mainly surveyed along coastal region and island. Autochthonous A. cochinchinensis was mainly distributed in sea shore below 1km from sea and founded 26 regions among 45 surveyed regions. Northern and eastern limited distribution of A. cochinchinensis was $N36^{\circ}15'$ in the west coast and $E128^{\circ}02'$ in the south coast of Korean peninsula, respectively. But it was not founded in the east coastal region. Dominant vegetation of surveyed area was pine with shrub. The number of tuberous roots of A. cochinchinensis growing in good light penetration was more than growing in bad light penetration.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.16 no.2
• /
• pp.83-91
• /
• 2004

The performance of wave control by a surface-mounted horizontal membrane is analyzed in the frame of linear potential theory. To employ the eigenfunction expansion method, the fluid domain is divided into two regions i.e. region without membrane and membrane-covered region. By matching the each solutions at boundaries of adjacent regions, the complete solution is obtained. The present analytical method solving the scattering problem directly gives the same results as Cho and Kim(1998)'s method solving the diffraction and the radiation problem separately. To verify the developed model, the model test with a surface-mounted horizontal membrane is conducted at the wave tank(36m${\times}$0.91m${\times}$l.22m). The analytic results are in good agreement with the experimental results. The reflection and transmission coefficients are investigated according to the change of membrane tension, length and incident frequencies.

• Journal of Korean Society for Atmospheric Environment
• /
• v.16 no.E2
• /
• pp.85-96
• /
• 2000

The concentrations of Pb, Mn, Al and Na were measured from a total of 26 snow samples collected from a 1.5-m deep snow pit in Livingston Island, South Shetland Islands, at the northern tip of the Antarctic Peninsula. Ore sampling location is great concern, because of its proximity to the southern extremity of south America, a candidate for the source regions of pollutant aerosols entering Antarctica. The mean concentrations of Pb and Mn were found to be 4.97 pg g(sup)-1 and 20.6 pgg(sup)-1, respectively. These concentrations levels are similar to those reported for recent snow at other Antarctic sites with pronounced spring maxima for both metals. Contributions form natural sources are estimated to be minor (∼16%) for Pb. For Mn, on the other hand, contribution from rock and soil dusts is found to be very important. Excess Pb over Pb from natural sources is likely to be anthropogenic, especially from South Americal. Our results show that yearly Pb fallout flux is much greater in Antarctic coastal areas than at other Antarctic locations far from the coast , indicating that the transport and deposition patterns of pollutant aerosols are not simple is Antarctica. It is also suggested that the recycling of anthropogenic Pb in seawater to the atmosphere could significantly contribute to the Pb fallout flux in the Antarctic coastal regions.

• Journal of Korean Neurosurgical Society
• /
• v.42 no.4
• /
• pp.258-264
• /
• 2007

Objective : The purpose of this study is to investigate the incidence of aneurysmal subarachnoid hemorrhage (SAH) in Youngdong district for 10 years. Methods : From Jan. 1997 to Dec. 2006, 732 patients (327 males, 405 females, mean age: $54.8{\pm}13.1$ years) with spontaneous SAH were admitted to our hospital. We reviewed the medical records and radiological findings regarding to the ictus of SAH, location and size of the ruptured aneurysms, Hunt-Hess grade and Fisher grade on admission, personal details such as address, age, and sex, and previous history of medical diseases. Results : In these 732 patients, 672 cases were confirmed as aneurysmal SAH. Among them, 611 patients (262 males, 349 females, mean age: $54.9{\pm}13.2$ years) came from Youngdong district. The average crude annual incidence of aneurysmal SAH for men, women, and both sexes combined in Youngdong district was $7.8{\pm}1.7$, $10.5{\pm}2.7$, and $9.1{\pm}2.1$ per 100,000 population, respectively. Because of the problems related to the observation period and geographical confinement, it was suspected that the representative incidence of aneurysmal SAH in Youngdong district should be made during the later eight years in six coastal regions. Therefore, the average age-adjusted annual incidence for men, women, and both sexes combined was $8.8{\pm}1.4$, $11.2{\pm}1.3$ and $10.0{\pm}1.0$, respectively in the coastal regions of Youngdong district from 1999 to 2006. Conclusion : In overall, our results on the incidence of aneurysmal SAH was not very different from previous observations from other studies.

• Journal of the Economic Geographical Society of Korea
• /
• v.16 no.2
• /
• pp.233-246
• /
• 2013

This paper investigates both the spatial patterns of aging population and its formal regional structure in 2010. The results are as follows: first, aging index shows high values in remote mountainous and coastal regions while showing relatively low values in Capital Region and large provincial cities. Aging index has low negative correlation with such variables as population increasing rate, ratio of youth population, ratio of apartments, and ratio of newly built housing. However, aging index shows high positive correlation with variables including ratio of single unit house, ratio of aged peoples' house ownerships, ratio of welfare recipients, ratio of old housing, and number of public healthcare facilities. Secondly, four factors are identified from factor analysis including aging factor, welfare factor, economic vitality factor, and new town factor. The aging level of a region is negatively related to the strong level of those factors. Thirdly, cluster analysis results in four different types of formal regions including rural mountainous coastal type, rural non-capital region type, large metropolitan type, and provincial industrial city type.

• Korean Journal of Environmental Biology
• /
• v.28 no.1
• /
• pp.40-48
• /
• 2010

A total of 63 taxa was identified with a mean abundance of total zooplankton ranging from 85~28,087 indiv.$m^{-3}$. Cluster and nMDS analysis showed that the study sites could be divided into two regions: North and East part of the sampling area (group A) and South part of the sampling area (group B). The number of taxa and species varied significantly among the two regions (ANOVA, p<0.05). The pattern of the spatio-temporal distribution of the zooplankton community in the coastal waters around the Wolseong Nuclear Power Plant is affected by the variations of seasonal water temperature. However, zooplankton community were no significant between the water temperature and heated discharge.