• Korean Journal of Environmental Biology
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• v.39 no.1
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• pp.19-31
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• 2021

We investigated the distribution characteristics of mussels (Mytilus coruscus) growing in the Geomundo sea area by water depth. The research was also conducted to identify the surrounding benthic organisms. Mussels showed high density and low obesity in low water depths. The lower the density, the higher the obesity level appeared in deeper water. The morphological characteristics also appeared to increase as the water depth deepened. In addition, the shell length and total weight were more strongly correlated at a depth of 12 m than at 2 m. The total weight by the growth of the shell length and shell height was affected by the water depth. The analysis showed that the density and biomass of the algae inhabiting the surroundings decreased somewhat as the water depth increased. In benthic animals, the number of mussels tended to decrease slightly at the point where oysters dominated, at a depth of 2 m. Conversely, the number of oysters tended to decrease in deeper water dominated by mussels. Thus, the spatial competition between oysters and mussels was affected by the water depth. Also, mussels did not appear in areas where large algae flourished, suggesting that the survival of mussels was affected by the presence or absence of large algae.

• Journal of Korean Society of Forest Science
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• v.106 no.3
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• pp.310-319
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• 2017

This study categorized the damaged trees by Supervised Classification using time-series-aerial photographs of Bukhan, Cheonggae and Suri mountains because oak wilt disease seemed to be concentrated in the metropolitan regions. In order to analyze the spatial characteristics of the damaged areas, the geographical characteristics such as elevation and slope were statistically analyzed to confirm their strong correlation. Based on the results from the statistical analysis of Moran's I, we have retrieved the following: (i) the value of Moran's I in Bukhan mountain is estimated to be 0.25, 0.32, and 0.24 in 2009, 2010 and 2012, respectively. (ii) the value of Moran's I in Cheonggye mountain estimated to be 0.26, 0.32 and 0.22 in 2010, 2012 and 2014, respectively and (iii) the value of Moran's I in Suri mountain estimated to be 0.42 and 0.42 in 2012 and 2014. respectively. These numbers suggest that the damaged trees are distributed in clusters. In addition, we conducted hotspot analysis to identify how the damaged tree clusters shift over time and we were able to verify that hotspots move in time series. According to our research outcome from the analysis of the entire hotspot areas (z-score>1.65), there were 80 percent probability of oak wilt disease occurring in the broadleaf or mixed-stand forests with elevation of 200~400 m and slope of 20~40 degrees. This result indicates that oak wilt disease hotspots can occur or shift into areas with the above geographical features or forest conditions. Therefore, this research outcome can be used as a basic resource when predicting the oak wilt disease spread-patterns, and it can also prevent disease and insect pest related harms to assist the policy makers to better implement the necessary solutions.

• Korean Journal of Ecology and Environment
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• v.55 no.2
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• pp.132-144
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• 2022

The fish community in the Seomjin River-Seomjin River Estuary-Gwangyang Bay coast continuum was investigated three times from March 2019 to October 2019. The collected species at the eight sites during the survey period were 49 species belonging to 31 families, including two endangered species. According to Bray-Curtis similarities, observations were divided into four groups based on the fish community composition; two groups (group 1, 2) and two uncategorized groups (group 3, 4). ANOSIM based on spatial and temporal groupings indicated that the spatial differences in fish communities (R=0.398, P=0.001) were relatively more important than the temporal differences (analysis of similarities, R=0.273, P=0.002). In particular, there were significant differences between groups 1 and 2 (analysis of similarities, R=0.556, P=0.001), and similarity percentage analysis revealed that Argyrosomus argentatus (9.4%), Favonigobius gymnauchen (6.9%) and Konosirus punctatus (5.9%) contributed to these differences of fish assemblages for each group. The fish fauna distributed in the Seomjin River-Gwangyang Bay ecosystem were spatially divided and the number of species and number of individuals showed seasonal differences. This study could be a basis for understanding changes in the fish community and implementing conservation and management strategies on major species within a continuous environment of the river-estuary-ocean continuum.

• Journal of Wetlands Research
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• v.18 no.4
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• pp.378-385
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• 2016

This study aims to suggest the framework of functional assessment on lotic area based on HGM(Hydrogeomorphic) approach targeting Wetland Protected Areas which are in the type of river channel, and to set up the fundamental data as a reference wetland. A total of 10 factors in terms of hydrology, biogeochemistry, plant habitat and animal habitat was analyzed based on the original approach of HGM and each Functional Capacity Index(FCI) of those factors was calculated. As the result of the modified FCI analysis, Damyang riverine wetland which is with artificial river bank had high values in the variables of area ratio of actual vegetation in the foreland, the number of plant per area and the area ratio of Salix spp., and those values were highly reflected on the factors of Nutrient Cycling(947,668.00), Species Richness and Maintain Characteristic Plant Communites(6.39) and Maintain Spatial Structure of Habitat(11.00). The Hanbando wetland which is keeping the natural bank had higher values in the variables of structural scale and species diversity, and the those values were highly reflected on the factors of Energy Dissipation(17,805.16), Subsurface Storage of Water(0.54), Removal of Imported Elements and Compounds(103,052.73), Maintain Characteristic Detrital Biomass(2.31), Maintenance of Interspersion and Connectivity (6.50), Species Diversity of Benthic macro-invertebrates(1.60) and Species Diversity of Vertebrate & Species Number of Other Animals(2.52/ 151.50), compared to the Damyang Riverine Wetland.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.317-324
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• 2021

This study deals with keywords from social media on domestic portal sites related to COVID-19, which is spreading widely. The data were collected between January 20 and August 15, 2020, and were divided into three stages. The precursor period is before COVID-19 started spreading widely between January 20 and February 17, the serious period denotes the spread in Daegu between February 18 and April 20, and the stable period is the decrease in numbers of confirmed infections up to August 15. The top 50 words were extracted and clustered based on TF-IDF. As a result of the analysis, the precursor period keywords corresponded to congestion of the Situation. The frequent keywords in the serious period were Nation and Infection Route, along with instability surrounding the Treatment of COVID-19. The most common keywords in all periods were infection, mask, person, occurrence, confirmation, and information. People's emotions are becoming more positive as time goes by. Cafes and blogs share text containing writers' thoughts and subjectivity via the internet, so they are the main information-sharing spaces in the non-face-to-face era caused by COVID-19. However, since selectivity and randomness in information delivery exists, a critical view of the information produced on social media is necessary.

• Journal of Marine Life Science
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• v.8 no.2
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• pp.121-127
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• 2023

The study was performed in order to understand the association between organic matter content in the sediments and the distribution of macrobenthos in the intertidal zone of the Muan bay. The sediment samples obtained from 21 sampling sites in August 2019 were analyzed for sediment composition and organic matter content (Ignition loss; IL and Total organic carbon; TOC). Further the macro benthos was sorted and enumerated. The sediments of inner area of bay has coarser composition where mouth part of bay, the sediments were predominantly silty. The highest organic matter content (both of IL and TOC) was measured at station 10 located near the Mokpo area while the lowest values was measured at station 20 adjacent to the north side of the bay. The 4 most abundant species accounted for more than 10% of all specimens were Assiminea sp., Musculista senhousia, Cerithideopsilla cingulate and Heteromastus filiformis. The maximum number of species and density were observed at station 10. Cluster analysis and non-metric multidimensional scaling (MDS) allow identification of four benthic assemblages based on species abundance. The correlation analysis revealed that there was a significant difference (p<0.05) in the density with TOC. Based on the analysis; it was found that the distribution of macrobenthos varied with the differences in sediment composition and organic matter content.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.2287-2300
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• 2015

This study examined the spatio-temporal distributions of the phytoplankton community in the coastal waters of Gogunsan Islands (CoWGIs), West Sea of Korea, from January to September 2011. A total of 104 species of phytoplankton belonging to 56 genera were identified. This was low compared to the surrounding seas of the West Sea. In particular, diatoms and dinoflagellates comprised 60.5% and 34.6%, respectively, and it was most diverse in autumn. The standing crops fluctuated from $9.6{\times}10^4cells/L$ to $1.0{\times}10^7cells/L$. This was high in winter and summer and low in spring and autumn. The seasonal dominant species were Skeletonema costatum-like species, Thalassiosira nordenskioeldii, Dactyliosolen fragillisimus, and Chaetoceros debilis in winter, Guinardia delicatula in spring, Eucampia zodiacus, Cylindrotheca closterium, Ch. debilis, and Ch. curvisetus in summer, and S. costatum-like species, Ch. debilis, Ch. curvisetus, G. delicatula, and Leptocylindrus danicus in autumn. The total number of autochthonous and tychopelagic species was 39 species. This showed a 1/3 (33.3%) decrease compared to the 1980's. The chlorophyll a concentration fluctuated from $3.82{\mu}g/L$ in autumn to $13.36{\mu}g/L$ in summer. The bio-oceanographic characteristics of the CoWGIs based on principle component analysis (PCA) showed that it was dominated by the Saemangeum water mass in the high temperature season and by the Geum River water mass in the low temperature season. In other words, there has been a conversion to a closed inner bay followed by the dramatic progress of eutrophication, even in the CoWGIs after completion of the Saemangeum embankment.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.2
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• pp.102-114
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• 2013

The basin of Lake Shihwa is one of highly industrialized region of Korea and a current environmental issue of study area is the operation of tidal power plant (TPP) to improve water quality. The application of water quality index (WQI) which integrates five physiochemical parameters (transparency, DO, DIN, DIP and chlorophyll-a) of water quality in Lake Shihwa and outer sea during 2011~2012 were performed not only to evaluate the spatial and temporal distribution of the water quality but also to assess the effect of water quality improvement by the operation of tidal power plant. The higher WQI values were observed in monitored sites near the industrial complexes in Lake Shihwa and the outfall of wastewater treatment plants (WWTPs) in outer sea. This indicates that the quality of seawater is influenced by diffuse non-point sources from industrial, municipal and agricultural areas in Lake Shihwa and by point sources from the effluence of municipal and industrial wastewater throughout WWTPs in outer sea. Mean WQI value decreased from 53.0 in 2011 to 42.8 in 2012 of Lake Shihwa. Water quality has improved significantly after TPP operation because enhancement of seawater exchange between Lake Shihwa and outer sea leads to improve a hypoxic condition which is primarily a problem in Lake Shihwa. Mean WQI of outer sea showed similar values between 2011 and 2012. However, the results of hierarchical cluster analysis and the deterioration of water quality in summer season indicate that the operation of tidal power plant was not improved the water quality in the upper most area of Lake Shihwa. To successfully improve overall water quality of Lake Shihwa, it is urgently necessary to manage and reduce of non-point pollution sources of the basin of Lake Shihwa.

• Korean Journal of Heritage: History & Science
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• v.42 no.3
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• pp.106-130
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• 2009

The aim of this paper is analysis of structure and development pattern about wooden coffin and chamber tombs in Gyeongju from the 2nd century B.C. to the 3rd century A.D. for researching to socio-political tendency and growth process of Sarokuk. Tombs buried with iron objects were built in Youngnam(嶺南) from the 2nd century B.C. with spread wooden coffin with stone mound(積石木棺墓). Also medium or small sized wooden coffin tombs buried with bronze mirror of western Han(前漢) and soft stoneware(瓦質土器) were appeared the 2nd century B.C. in Gyeongju, because of establishment of Han's commanderies(漢郡縣) in the Korean Peninsula and refuge from Daedong river(大同江) to Jinhan(辰韓). Separate tombs(獨立墓) with lots of bronze object ware assumed high ranked tombs of parsonage(司祭王) or local chief(地域首長). From the 2nd century A.D. the size of wooden coffin tombs became enlarged and funerary objects ware abundant, for example Sarari 130th tomb(舍羅里 130號). The burying pattern of this tomb is similar to wooden chamber tombs in Lelang(樂浪), which had prestige goods like lacquer ware and bronze mirror in wood box(木匣) beside coffin. Appearance of these wooden chamber tombs that were different from original wooden coffin tombs imply interaction between Lelang and these area with iron. Sarari community that held right of trade and distribution to outside through the geographical advantage grew up centered position in Gyeongju politically, socially, and culturally. Chamber in tomb as a new structural notion that can secure funerary objects became firmly was established from the 2nd century A.D. in Gyeongju and large sized wooden chamber tombs were generally built early of the 3rd century A.D. This tendency was reflected in stratification of community and growth as center of local state. After late of the 3rd century A.D. Gyeongju type wooden chamber tomb(慶州式木槨墓) which had subordinate outer coffin(副槨) was appeared and then subordinate outer coffin was as bigger as main chamber(主槨) the 4th century A.D., because of centralization and stratification in society and unification of various communities among the Gyeongju area.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.2
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• pp.59-71
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• 2014

At present, Korean one-person households have been continuously increased in spite of the reduction of total population. The increasement of one-person household has become a social and institutional issue. It is necessary to response socially and economically to not only changes of housing demand but also the disadvantaged classes such as the socially weak and single elderly household from the national level. In this respect, this research examined the spatial distribution (such as the increasing area, high-density area, and majority area) of one-person household with census data in the city of Busan. The clusters of one-person households were selected by focusing on the spatial distributions by time series changes of 2000, 2005, and 2010 and considering their housing characteristics. In terms of policy efficiency, the clusters of one-person households to be supported by priority were derived by analyzing the census data from 6066 output areas in the city of Busan. As a result, lots of one-person households of juniors were distributed around the university town, office facility, and station service area. Lots of one-person households at middle-aged class were distributed in Busan's original downtown and mountain-side road. Generalizing these characteristics, cluster analysis was conducted. As a result, one-person household dense area in Busan could be classified into four types. This research should be utilized as a counterplan for increasing the housing demand of one-person household or basic data for supporting small housing supply policies in the future.