• Geomechanics and Engineering
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• v.12 no.3
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• pp.523-539
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• 2017

Clay soils are typical for their swelling properties upon absorption of water during rains and development of cracks during summer time owing to the profile desorption of water through the inter-connected soil pores by water vapour diffusion leading to evaporation. This type of unstable soil phenomenon by and large poses a serious threat to the strength and stability of structures when rest on such type of soils. Even as lime and cement are extensively used for stabilization of clay soils it has become imperative to find relatively cheaper alternative materials to bring out the desired properties within the clay soil domain. In the present era of catastrophic environmental degradation as a side effect to modernized manufacturing processes, industrialization and urbanization the creative idea would be treating the waste products in a beneficial way for reuse and recycling. Bottom ash and ecosand are construed as a waste product from cement industry. An optimal combination of bottom ash-eco sand can be thought of as a viable alternative to stabilize the clay soils by means of an effective dispersion dynamics associated with the inter connected network of pore spaces. A CATIA model was created and imported to ANSYS Fluent to study the dispersion dynamics. Ion migration from the bottom ash-ecosand pile was facilitated through natural formation of cracks in clay soil subjected to atmospheric conditions. Treated samples collected at different curing days from inner and outer zones at different depths were tested for, plasticity index, Unconfined Compressive Strength (UCS), free swell index, water content, Cation Exchange Capacity (CEC), pH and ion concentration to show the effectiveness of the method in improving the clay soil.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.4
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• pp.611-634
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• 2017

In rapid urbanization, demand for utility tunnel increases more, and tunnel boring machine (TBM) has been used widely. Prediction of TBM penetration rate is important for proper estimation of construction period and cost. Although there are several methods, such as NTNU model and CSM model that require many input parameters, fundamental understanding on correlations between rock properties and TBM penetration rate is critical. In this study, we explored the brittleness indices of hard rocks according to various definitions, and the correlations between the brittleness indices and the TBM penentration rates.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.6
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• pp.857-870
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• 2017

The use of shield TBM is gradually increasing due to the urbanization of social infrastructures. Reliable estimation of advance rate is very important for accurate construction period and cost. For this purpose, it is required to develop the prediction model of advance rate that can consider the ground properties reasonably. Based on the database collected from field, statistical prediction procedure for field penetration index (FPI) was modularized in this study to calculate penetration rate of shield TBM. As output parameter, FPI was selected and various systems were included in this module such as, procedure of eliminating abnormal dataset, preprocessing of dataset and ridge regression with best subset selection. And it was finally validated by using field dataset.

• Korean Journal of Environment and Ecology
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• v.27 no.2
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• pp.170-195
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• 2013

This study was carried out to investigate the vascular flora of Mt. Nam, Mt. Toham, and Mt. Danseok in Gyeongju National Park. The vascular plants were surveyed for 7 times from July 2011 to May 2012. The results were summarized as 436 taxa, 96families, 284 genera, 385 species, 4 subspecies, 41 varieties, and 6 forms. The 13 taxa were categorized as Korean endemic plants species and the other 7 taxa as rare plants species, which categorized by the Korea Forest Service. Based on the Floristic Degrees categorized by the Specific Distribution of Plants Species, one taxa grouped as the Floristic Degree V, 3 for Floristic Degree IV, and 9 for Floristic Degree III, 4 for Floristic Degree II, and 24 taxa for Floristic Degree I. The naturalized plants were recorded as 29 taxa, and their Naturalization Ratio and Urbanization Index were recorded as 6.65%, and 9.03%, respectively. 436 taxa listed consists of 182 taxa(41.7%) of pasturing plant, 176 taxa(40.4%) of edible plants, 147 taxa(33.7%) of medicinal plants, 52 taxa(11.9%) of ornamental plants, 18 taxa(4.1%) of timber plants, 16 taxa(3.7%) of stain plants, 8 taxa(1.8%) of fiber plants, 1 taxa(0.2%) of industrial plants and 79 taxa(18.1%) of unknown plants.

• Korean Journal of Environment and Ecology
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• v.23 no.2
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• pp.105-115
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• 2009

The naturalized plants in the Byeonsanbando National Park were listed 88 taxa composed of 24 families, 65 genus, 83 species and 3 varieties and 2 forms by field survey. The naturalized plants divided into pattern by survey of annual plants ratio is 38 taxa (43.2%) by life form spectrum and perennials is 28 taxa (31.8%), biennials is 19 taxa (21.6%), two trees (Robinia pseudoacacia, Ailanthus altissima) and one shrub (Amorpha furticosa) were founded. According to analysis results form place of origin, Europe covered 26 taxa (37.1%), North America covered 23 taxa (32.8%). Naturalized degree 3 plants, as common but not abundant, founded as 28 taxa (31.8%) were hold most highly ratio, naturalized degree 1 plants founded as 8 taxa (9.1%) were hold lowest. Introduction period 1 covered 39 taxa (44.3%) have had highest score and period 2 covered 16 taxa (18.2%) have had lowest scores. In addition, the urbanization index based on 271 taxa was 32.5% and Ambrosia artemisiaefolia is growing by ecosystem disturbing wild plants. Meanwhile, Ambrosia artemisiaefolia have confirmed into district of introduction in the Byeonsanbando National Park were damage the human body of plants develop an allergy to pollen. Therefore, management counterplan of the sequel of monitoring them might be required, introduction into naturalized plants are grasp of ecological characteristics and systematical management plan from this point of time by require.

• Korean Journal of Plant Resources
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• v.33 no.4
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• pp.365-397
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• 2020

To investigate the distribution of vascular plants growing at Apsan park, we surveyed from April in 2018 to October in 2019. The flora of Apsan park was classified as a total of 721 taxa comprising of 114 families, 382 genus, 619 species, 5 subspecies, 77 varieties, 12 forma, 5 hybrid, 3 cultivation. Among them, The Rare plants species 23 taxa, endemic plants 15 taxa, floristic regional indicator plants 98 taxa, naturalized plants 57 taxa were recorded. The percentage of urbanization index was 17.76%, the naturalized ratio was 7.91%, respectively.

• Economic and Environmental Geology
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• v.38 no.3 s.172
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• pp.221-236
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• 2005

In order to investigate the contamination levels and dispersion patterns of heavy metals such as Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn by urbanization, soils beneath roadside-trees and leaves of Ginkgo biloba were collected from Seoul area during October to November in 2001. All tree leaves were grouped into washed and unwashed ones. The pH of most soil ranges from 6 to 9 indicating a weak acidic and alkaline. The element couples of Cd-Co, Cr-Ni and Zn-Cu-Pb have good correlation in soils, and contamination sources of Cd-Co, Cr-Ni and Zn-Cu-Pb could be similar. High correlation coefficients among Pb, Cu and Zn in G. biloba indicates that these elements show the similar behavior during the metabolism processes. From the results of pollution index calculation for soils, industrialized and heavy traffic area were severly polluted by heavy metals such as Cd, Cu, Pb and Zn. By the discriminant analysis, industrialized and heavy traffic areas are enriched in the order of Ni> Cr> Pb. Cadmium is useful to discriminate between industrialized and heavy traffic areas, Co and Pb are highly enhanced in heavy traffic area.

• Korean Journal of Plant Resources
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• v.32 no.5
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• pp.589-614
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• 2019

To investigate the distribution of vascular plants growing at Mt. Guryong, we surveyed from March in 2016 to October in 2017. The flora of Mt. Guryong was classified as a total of 526 taxa comprising of 87 families, 298 genus, 449 species, 4 subspecies, 63 varieties, 10 forma. Among them, the endemic plants in Korea were investigated as 10 taxa of including Pseudostellaria coreana (Nakai) Ohwi. The Korean rare plants species were investigated as 16 taxa, among them degree of CR investigated as 1 taxa of Cypripedium macranthum Sw., VU investigated as 5 taxa of including Rhododendron micranthum Turcz., degree of LC investigated 9 taxa of including Clematis koreana Kom., degree of DD investigated 1 taxa of Adenophora grandiflora Nakai. Endemic plants were investigated as 14 taxa of including seudostellaria coreana (Nakai) Ohwi and The floristic special plants were a total of 84 taxa such as 2 taxa in degree V(in cluding Polypodium virginianum L.), 7 taxa in degree IV (including Anemone reflexa Steph. & Willd.), 21 taxa in degree III(including Celtis aurantiaca Nakai), 22 taxa in degree II (including Thelypteris phegopteris (L.) Sloss.) and 31 taxa in degree I (including Cimicifuga simplex (DC.) Turcz.) was carried out to provide basic data. The naturalized plants were investigated as 37 taxa of including Chenopodium ficifolium Smith., Thlaspi arvense L., Rumex crispus L. and the percentage of urbanization index was 11.53%, the naturalized ratio was 6.99% respectively.

• Ecology and Resilient Infrastructure
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• v.7 no.4
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• pp.374-387
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• 2020

This study was conducted to provide basic data for monitoring the trend of ecosystem change and establishing management plans for wetland protection areas by understanding the status of naturalized plants. In 21 wetland protection areas, 129 taxa, including 10 invasive alien species, were recorded. The naturalized plants appeared mostly as 71 taxa in the Chimsil wetland and were not observed in the Moojechineup and Sumeunmulbaengdui wetlands. Among the naturalized plants, 42 taxa (32.6%) originated from North America. Annual and biennial plants accounted for 68.2% (88 taxa). The frequencies of occurrence of naturalized plants growing in dry secondary grasses such as Erigeron annuus and Trifolium repens were high, and clonal plants that propagated by making stolons and struck roots accounted for 19.4% (25 taxa). The naturalized and urbanization indices showed positive correlations with location factors such as wetland, agricultural land, and used area. However, a negative correlation was found between altitude and forest. Therefore, a management plan that synthetically considers the occurrence frequency and growth characteristics of naturalized plants as well as the locational characteristics of wetland protection areas is required.

• Journal of the Korean Geographical Society
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• v.37 no.4
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• pp.385-402
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• 2002

This study examined temporal and spatial patterns of bioclimatic perceived sultriness in South Korea by analyzing the climatology of heat index calculated from ambient temperature and relative humidity for the period of 26 years (1973-1998). As results, spatially, bioclimatic sultriness above all thresholds frequently occurred mainly in the central western inner area, the southwestern inner area, and the southeastern inner area of South Korea. Especially, Miryang in the southeastern inner area of South Korea was proved to be, bioclimatically, the sultriest area in South Korea that has recorded frequent high heat index. Temporally, frequency of sultriness in the contiguous South Korea significantly increased in the 1990s. Specifically, In 1994, frequencies of heat index exceeding each threshold was the highest all over South Korea. Normally, the sultriness with high heat index exceeding 40.6$^{circ}C$ occurred mainly for the period of between the end of July generally after Summer Changma and the beginning of August before another small rainy season of years. These temporal-spatial distributions of bioclimatic sultriness in South Korea showed various patterns regionally, affected by physical and anthropogenic climatic factors such as topography, latitude, altitude, water bodies or aforestration, urbanization, and industrialization as well as movements of large-scale air masses.