• Korean Journal of Ecology and Environment
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• v.45 no.1
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• pp.129-138
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• 2012

We investigated an ecological impact of drought simulated by discharge depletion on the water quality and benthic diatom community in the indoor experimental channel. As artificial substrates slide-glass was installed in acrylic channel for 16 days. Channels were supplied continuously with eutrophic lake water with a discharge rate of 6 L $min^{-1}$ in duplication during the colonized period. And then during the discharge depletion period, three discharge rates were provided: NDF (No depletion of flow rate (Control): 6 L $min^{-1}$), LDF (Low depletion of flow rate: 3 L $min^{-1}$) and HDF (High depletion of flow rate: 1 L $min^{-1}$). Environmental factors in the water, such as suspended solid, Chl-$a$ and nutrients concentration, were measured with periphytic algae including AFDM (ash free dry matter), Chl-$a$ concentration and cell density at 1-day intervals. Light intensity increased significantly with discharge depletion (F=229.5, p= 0.000). $NH_4$-N concentration was highest at HDF. Suspended solid in outflowing water decreased at HDF (88%), LDF (97%) and NDF (99%), compared to inflowing water (100 %). Chl-$a$ in substrates increased more than two times at LDF and HDF than NDF (F= 8.399, p=0.001). Also AFDM and benthic diatom density increased significantly at LDF and HDF than NDF (F=9.390, p=0.001; F=6.088, p=0.007). In all experimental groups, $Aulacoseira$ $ambigua$, $Achnanthes$ $minutissima$ and $Aulacoseira$ $granulata$ were dominant species accounting for greater than 10% of benthic diatom density. The most dominant species, $A.$ $ambigua$ was highest at LDF, followed by HDF and NDF (F=8.551, p=0.001). In conclusion, the effect of drought simulated by discharge depletion in an artificial stream ecosystem caused significant changes on water quality and benthic diatom biomass. This result provides a useful data to understand the effect of draught on stream ecosystem in situ.

• Korean Journal of Ecology and Environment
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• v.45 no.1
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• pp.110-122
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• 2012

This study examined the benthic diatom community distribution, land cover/use and water quality in relation to stream shape complexity (SSC) in the Seom River watershed. SSC showed a significant relation to the riparian land cover/use pattern and also water quality variables of the studied streams. Streams with high stream shape complexity (HSC) appeared to have a high proportion of forest and farmland, while streams having a low stream shape complexity (LSC) appeared to have high proportion of city. Streams with lower SSC showed higher nutrients concentration in the stream waters. Benthic diatom species composition and dominant species appeared to be similar regardless of SSC differences among the studied streams, while the variation of diatom density was manifested with SSC. The relative abundance of dominant benthic diatoms varied with SSC. Saprophilic diatoms were dominant in the streams of LSC, while saproxenic diatoms were dominant in the streams of HSC. During the evaluation of biological water quality using the benthic diatom indices, Trophic Diatom Index (TDI) and Diatom Assemblage Index to organic water pollution (DAIpo), the streams of LSC generally showed poorer water quality than those of MSC (Middle stream shape complexity) and HSC. In particular, BOD, TP, and $PO_4$-P showed significant relationships with DAIpo. In conclusion, shape complexity of streams in the Seom River watershed showed a close relation with benthic diatom distribution. This relation seemed to primarily be resulted from the effect of proximate factors, such as water quality, which might be affected by the land use types determining the degree of SSC.

• Korean Journal of Ecology and Environment
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• v.47 no.2
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• pp.103-115
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• 2014

Forest vegetation of Noinbong (1,338 m) in Odaesan National Park is classified into mountain forest vegetation. Mountain forest vegetation is subdivided into deciduous broad-leaved forest, mountain valley forest, coniferous forest, subalpine coniferous forest, subalpine deciduous forest, shrub forest, riparian forest, afforestation and other vegetation. Including 196 communities of mountain forest vegetation and 7 communities of other vegetation, the total of 203 communities were researched; mountain forest vegetation classified by physiognomy classification are 62 communities deciduous broad-leaved forest, 85 communities of mountain valley forest, 18 communities of coniferous forests, 3 communities of subalpine coniferous forests, 4 communities of subapine deciduous forests, 2 communities of shrub forests, 1 communities of riparian forests, 21 afforestation and 7 other vegetation. As for the distribution rate for surveyed main communities, Quercus mongolica, Quercus serrata, Quercus variabilis communities account for 54.856 percent of deciduous broad-leaved forest, Fraxinus mandshurica - Cornus controversa community takes up 15.482 percent of mountain valley forest, Pinus densiflora community holds 78.091 percent of mountain coniferous forest holds. In conclusion, minority species consisting of Quercus mongolica, Pinus densiflora, Tilia amurensis, Fraxinus mandshurica, Cornus controversa, Quercus serrata, and Quercus variabilis are distributed as dominant species of the uppermost part in a forest vegetation region in Odaesan National Park. In addition, because of vegetation succession and climate factors, numerous colonies formed by the two species are expected to be replaced by Quercus mongolica, Carpinus laxiflora and Fraxinus mandshurica which are climax species in the area.

• Korean Journal of Ecology and Environment
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• v.47 no.2
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• pp.91-102
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• 2014

Forest vegetation of Birobong (1,563 m) in Odaesan National Park is classified into mountain forest vegetation and flatland forest vegetation. Mountain forest vegetation is subdivided into deciduous broad-leaved forest, valley forest, coniferous forest, subalpine coniferous forest, subalpine broad-leaved forest, afforestation and etc., while riparian forest was found under the category of flatland forest vegetation. Including 196 communities of mountain forest vegetation, 1 community of flatland forest vegetation and 4 communities of other vegetation, the total of 201 communities were researched; the distributed colonies classified by physiognomy classification are 62 communities deciduous broad-leaved forest, 84 communities of valley forest, 15 communities of coniferous forests, 16 communities of subalpine coniferous forest, 3 communities of subalpine broad-leaved forest, 16 afforestation, 1 community of flatland forest and 4 other communities. As for the distribution rate for surveyed main communities, Quercus mongolica, Quercus variabilis, Tilia amurensis communities account for 37.08 percent of deciduous broad-leaved forest, Juglans mandshurica, Fraxinus mandshurica, Cornus controversa, Populus koreana community takes up 1.59 percent of mountain valley forest, Pinus densiflora community holds 6.65 percent of mountain coniferous forest holds. In conclusion, minority species consisting of Quercus mongolica, Quercus variabilis, Tilia amurensis, Juglans mandshurica, Fraxinus mandshurica, Cornus controversa, Populus koreana, Pinus densiflora are distributed as dominant species of the uppermost part in a forest vegetation of Birobong in Odaesan National Park. In addition, because of vegetation succession and climate factors, numerous colonies formed by the two species are expected to be replaced by Quercus mongolica, Tilia amurensis and Juglans mandshurica which are climax species in the area. However, the distribution rate of deciduous broad-leaved forest seems to increase gradually due to global warming and artificial disturbance.

• Korean Journal of Ecology and Environment
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• v.46 no.4
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• pp.570-580
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• 2013

The forest vegetation of the Deogyusan National Park is classified into mountain forest vegetation and riparian forest vegetation. Mountain forest vegetation in the forest vegetation is subdivided into deciduous broad-leaved forest, valley forest, coniferous forest, subalpine coniferous forest, shrub forest, afforestation and other vegetation. Including 192 communities of mountain forest vegetation and 3 communities of other vegetation, the total of 195 communities were researched; the distributed colonies classified by physiognomy classification are 61 communities deciduous broad-leaved forest, 55 communities of valley forest, 17 communities of coniferous forests, 6 communities of subalpine coniferous forest, 3 communities of shrub forest, 50 afforestation and 3 other vegetation. As for the distribution rate for surveyed main communities, Quercus mongolica, Quercus serrata, Quercus variabilis communities account for 66.00 percent of deciduous broad-leaved forest, Fraxinus mandshurica, Cornus controversa community takes up 64.40 percent of mountain valley forest, Pinus densiflora community holds 70.40 percent of mountain coniferous forest holds. In conclusion, minority species consisting of Quercus mongolica, Quercus serrata, Quercus variabilis, Fraxinus mandshurica, Cornus controversa, Pinus densiflora are distributed as dominant species of the uppermost part in a forest vegetation of Geochilbong in Deogyusan National Park. In addition, because of vegetation succession and climate factors, numerous colonies formed by the two species are expected to be replaced by Quercus mongolica, Carpinus laxiflora and Fraxinus mandshurica which are climax species in the area. However, the distribution rate of deciduous broad-leaved forest seems to increase gradually due to global warming and artificial disturbance.

• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.289-300
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• 2013

Forest vegetation of Hyangjeokbong (1,614 m) in Deogyusan National Park is classified into mountain forest vegetation and flatland forest vegetation. Mountain forest vegetation is subdivided into deciduous broad-leaved forest, valley forest, coniferous forest, subalpine coniferous forest, shrub forest, grassland forest, afforestation and etc., while riparian forest was found under the category of flatland forest vegetation. Including 122 communities of mountain forest vegetation and 2 communities of riparian forest, the total of 124 communities were researched; the distributed colonies classified by physiognomy classification are 42 communities deciduous broad-leaved forest, 37 communities of valley forest, 8 communities of coniferous forests, 6 communities of subalpine coniferous forest, 3 communities of shrub forest, 1 communities of grassland forest, 21 afforestation and 4 other communities. As for the distribution rate for surveyed main communities, Quercus mongolica, Quercus serrata, Quercus variabilis communities account for 47.02 percent of deciduous broad-leaved forest, Fraxinus mandshurica community takes up 57.48 percent of mountain valley forest, Pinus densiflora community holds 77.53 percent of mountain coniferous forest holds, and Taxus cuspidate-Abies koreana community takes up about 50 percent of subalpine coniferous forest. Mountain shrub forest and mountain grassland forest vegetation are concentrated mainly on the top of Hyangjeokbong and the ridge connecting the top and Jungbong. Meanwhile, riparian forest vegetation comprises 0.024% of the whole vegetation area in a study area. In conclusion, minority species consisting of Quercus mongolica, Quercus serrata, Quercus variabilis, Fraxinus mandshurica, Cornus controversa, Pinus densiflora, Abies koreana and Taxus cuspidata are distributed as dominant species of the uppermost part in a forest vegetation region in Deogyusan National Park. In addition, because of vegetation succession and climate factors, numerous colonies formed by the two species are expected to be replaced by Quercus mongolica, Carpinus laxiflora and Fraxinus mandshurica which are climax species in the area. However, in respect of subalpine coniferous forest, the distribution rate of deciduous broad-leaved forest seems to increase gradually due to global warming and artificial disturbance.

• Korean Journal of Ecology and Environment
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• v.46 no.4
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• pp.551-560
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• 2013

Environmental factors and epilithic diatom communities in the lower streams near the harbor region of South Korean peninsula were examined during no monsoon period in May 2013. The sampling of water and epilithic diatoms was conducted at both streams, 19 regulated streams (RS) that there are one or several dams constructed in the river system, and 19 un-regulated streams (US) that there are no dams within the river. A cluster analysis based on the number of species and abundance of epilithic diatoms through the stations, divided into three groups such as groups I (mainly US), II (mixed with US and RS) and III (mainly RS), respectively. Group I showed that water quality is good and high diversity of diatom, while Group II and III was water quality is relatively poor, but not differed in biomass of diatom from Group I. In addition, Group II that had high conductivity, nitrogen and phosphorus, was the lowest in diatom diversity among them. Dominant species were Nitzschia palea (17%) and Navicula seminuloides (11%) in Group I, Nitzschia inconspicua (19%) and Navicula perminuta (9%) in Group II, and Nitzschia inconspicua (15%) and Nitzschia palea (14%) in Group III, respectively. These taxa were widely distributed in brackish water, and not closely related with specific water quality, like eutrophic water. However, the groups II and III belonged to RS, had not only little biomass, but bad water quality such as high concentrations of nutrient and chlorophyll-a. Therefore, to determine the effect of dam construction on the lower water ecosystem, the planktonic algae, which can occur algal bloom in the estuary, also was considered to be a parallel investigation.

• Journal of Yeungnam Medical Science
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• v.15 no.2
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• pp.325-340
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• 1998

A cross-sectional study was conducted to evaluate the relationship between sick building syndrome(SBS) and the environmental factors affecting SBS on 130 underground workers and 60 controls. The study consisted of 1) a review of environmental condition 2) measurement of temperature, $O_2$, $CO_2$, CO, and formaldehyde and 3) a questionnaire survey of symptom prevalence and perception of environmental conditions using indoor Air Quality questionnaire recommended by National Institute for Occupational Safety and Health. Bronchitis and dust allergy were more prevalent in underground workers significantly(p < 0.05). Among the 18 symptoms related to the indoor air pollution, the experience rate of dry, itching or irritated eyes, sore or dry throat, chest tightness, tired or strained eyes and dry or itchy skin symptom was significantly different between the underground workers and controls. The diagnostic criteria of SBS was defined as at least 1 symptom is experienced 1-3 times a week during the last 1 month among 18 indoor air pollution related symptoms which can be relieved by moving out of the underground. Applying the criteria, the mean symptom score was significant higher in underground workers than controls significantly (p < 0.05). These resalts indicated that underground workers are under inappropriate ergonomic and physical condition and inadequate ventilation. Their experience rate of symptoms related to indoor air pollution and prevalence of SBS was significantly higher than controls. To reduce the prevalence of SBS of underground workers, the surveillance system of indoor air quality, restriction of using fuel in underground and legislative regulations for the environment are needed to establish a better indoor air quality. Early detection, treatment and prevention of SBS through medical attention is also needed.

• Journal of Korea Port Economic Association
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• v.30 no.3
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• pp.163-185
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• 2014

The growth of a city requires substantial resources, an appropriate environment, and the alignment of several factors. City growth also evolves through changes in its history, culture, economics, societies, groups, and government systems. However, current port city development plans designed to encourage the growth of local businesses fail to provide the support needed for both the city and businesses. The recent actions of urban administrations and federal and local governments have revealed that they have yet to create a mature decentralized management system, or perhaps have ignored the reality of needing one. Taking a clear look at the differences between port regions, such as Gwangyang and Pyeongtaek, and understanding their effect on city growth would be a prudent course of action when preparing for future developments. The purpose of this study is to determine the relationship between ports and cities by analyzing the effect of port characteristics on nearby city growth. This study used a comparison analysis to determine how port characteristics affected the growth of Pyeongtaek and Gwangyang. One result of this analysis showed that an increase in the number of goods being imported or exported had a positive effect on the growth of both port cities, In this respect, an aggressive plan and cooperation between the federal and local government should occur simultaneously. Furthermore, efficient local policies that focus on the increase of personnel and material resources should be pursued as a standard strategy, which would also promote the international status of these locations. The results of this study show the importance of government cooperation. The federal government should lead with aggressive strategies that aim to optimize efficiency, while the local government should provide the necessary assistance and coordination in order to achieve optimal results.

• Economic and Environmental Geology
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• v.53 no.1
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• pp.45-69
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• 2020

In Danyang area, various geological structures as well as various lithology and strata are well developed, which are useful for studying paleo-environment and structural movements, and also typical karst landforms, wethering landforms and river landforms. If geologically and geomorphologically valuable resources are used in terms of geotourim perspective, it is expected that revitalization of regional economy through diversification of attracting factors and employment creation of local people. Danyang has many excellent geological resources for geological field trip, they can greatly contribute to the development of geology such as expanding the base of geology and cultivating successive generations. In this study, we have evaluated newly discovered sites and previously excavated resources based on academical and educational values. By using these geological and geomorphological resources, we suggest three geotrail courses as follows. First, Geo-trail A is mainly focused on geological structures (Route A: Jeong Hwan Route), where we can learn geological deformation and movement through various brittle and ductile deformation structures. Second, Geo-trail B is mainly focused on stratigraphic importance (Route B: Soon-Bok Route), which emphasizes on various rocks, strata and contact relationship. Third, Geo-trail C is mainly focused on geomorphological landforms and landscapes (Route C: Satgat Route), which provide information about different geomorphological landforms and the interaction between different geological agents. In order to operate these geotrail courses efficiently, installation of explanation boards and view points, cultivate local commentators, and visitor centers and experience programs should be properly prepared together.