• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.201-210
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• 2019

Recently, due to the efforts to mitigate traffic congestion and expansion of space efficiency, the construction of underground roads has been increased in big-scale cities. Since tunnels in the city have a higher chance for a fire leading to a great tragedy during a severe traffic jam than mountain tunnels, it is highly likely that it will be constructed as a tunnel, having a small cross section, for small vehicles. However, if they are constructed as such small-vehicle tunnels, it would be possible to reduce the design fire intensity while the concentration of harmful gases would increase due to a reduction in the small cross sectional area, led by a decrease in the tunnel height. In this study, behaviors of fire smoke by the installation interval and format of large-scale exhaust-gas ports were examined and compared in the analysis of temperatures and CO concentrations of a tunnel and its results were as the following. Although there were no significant differences in the smoke spreading distance between installation intervals, but in this study, 100 m was found to be the most effective installation interval. The smoke exhaustion performance was found to be excellent in the order of $4m{\times}3m$, $6m{\times}2m$, and $3m{\times}2m$ (2 lane) of the smoke spreading distance. Although there was no significant difference in the smoke spreading distance between formats of large-scale exhaust-gas ports, it was found that the smoke spreading distance was larger than other cases when it was $3m{\times}2m$ in the fire growing process. The analysis of smoke spreading distances by the aspect ratio showed that a smoke spreading distance was shorted when its the smoke spreading distance was found to be shorter when its traverse distance was relatively longer than its longitudinal distance.

• Ecology and Resilient Infrastructure
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• v.7 no.4
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• pp.262-273
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• 2020

Amending biopolymers such as β-glucan (BG) and Xanthan gum (XG) generally enhances soil strength by ionic and hydrogen bonds between soil particles. Thus, biopolymers have been studied as eco-friendly construction materials in levees. However, physiological responses of plants grown on soil amended with biopolymers are not fully understood. This study focuses on the effects of biopolymers on the growth of Camelina sativa L. (Camelina) under excess zinc (Zn) stress. The optimal concentrations of BG and XG were confirmed to have a 0.5% ratio in soil depending on the physiological parameters of Camelina under excess Zn stress. The Zn binding capacity of biopolymers was investigated using 1,5-diphenylthiocarbazone (DTZ). The reduction of Zn damage in Camelina was evaluated by analyzing the Zn content and expression of heavy metal ATPase (HMA) genes under excess Zn stress. Amendments of BG and XG improved Camelina growth under excess Zn stress. In DTZ staining and ICP-OES analysis, Camelina grown on BG and XG soil showed less Zn uptake than normal soil under excess Zn stress. The Zn-inducible CsHMA3 gene was not stimulated by either BG or XG amendment under excess Zn stress. Moreover, both BG and XG amendments in soil exhibit Zn-stress mitigation similar to that of Zn-tolerant CsHMA3 overexpres sed Camelina. These results indicate that biopolymer-amended soils may influence the prevention of Zn absorption in Camelina under excess Zn stress. Thus, BG and XG are proven to be suitable materials for levee construction and can protect plants from soil contamination by Zn.

• Korean Journal of Environmental Biology
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• v.39 no.2
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• pp.184-194
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• 2021

Since the construction of a dike in 1983, the water quality in the Bunam Lake has continued to deteriorate due to algal bloom caused by agricultural nutrient loading. Therefore, we evaluated the change in water quality and phytoplankton ecological characteristics in Bunam Lake and Cheonsu Bay, Korea. Water temperature, salinity, dissolved oxygen, chemical oxygen demand (COD), chlorophyll, and phytoplankton community were surveyed in April during the dry season and in July during the rainy reason. As a result, during the dry period, phytoplankton proliferated greatly and stagnated in the Bunam Lake while a very high population of cyanobacteria Oscillatoria spp. (8.61×10⁷ cells L^-1) was recorded. Most of the nutrients, except, nitrate and nitrite, were consumed due to the large growth of phytoplankton. However, during the rainy period, concentrations of ammonia, phosphate, silicate, nitrate, and nitrite, were very high towards the upper station due to the inflow of fresh water. Cyanobacteria Oscillatoria and Microcystis spp. were dominant in the Bunam Lake during the rainy period. Even in the Cheonsu Bay, cyanobacteria dominated due to the effect of discharge and diatoms, such as, Chaetoceros spp. and Eucampia zodiacus, which also proliferated significantly due to increased levels of nutrients. Since the eutrophication index was above 1 in Bunam Lake, it was classified as eutrophic water and the Cheonsu Bay was classified as eutrophic water only during the rainy season. In addition, a stagnant seawater-derived hypoxia water mass was observed at a depth of8m in the Bunam Lake adjacent to the tide embankment and the COD concentration reached 206 mg L^-1 in the bottom layer at B3. Based on this result, it is considered that the water quality will continue to deteriorate if organic matters settle due to continuous inflow of nutrients and growth of organisms while the bottom water mass is stagnant.

• Journal of the Korean earth science society
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• v.42 no.1
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• pp.39-54
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• 2021

Damyang Wetland, a riverine wetland, has been designated as the first wetland protection area in South Korea and is a candidate area for the Mudeungsan Area UNESCO Global Geopark. The Damyang Wetland area is the upstream part of the Yeongsan River and is now a relatively wide plain. To reconstruct the sedimentary environment around the Damyang Wetland, core samples were obtained, and sedimentary facies analysis, AMS and OSL age dataings, grain size, and geochemical analyses were carried out. In addition, comprehensive sedimentary environment changes were reconstructed using previous core data obtained from this wetland area. In the Yeongsan River upstream area, where the Damyang Wetland is located, fluvial terrace deposits formed during the late Pleistocene are distributed in an area relatively far from the river. As a gravel layer is widely distributed throughout the plains, Holocene sediments were likely deposited in a braided river environment when the sea level stabilized after the middle Holocene. Then, as the sedimentary environment changed from a braided river to a meandering river, the influx of sand-dominated sediments increased, and a floodplain environment was formed around the river. In addition, based on the pollen data, it is inferred that the climate was warm and humid around 6,000 years ago, with wetland deposits forming afterward. The the trench survey results of the river area around the Damyang Wetland show that a well-rounded gravel layer occurs in the lower part, covered by the sand layer. The Damyang Wetland was likely formed after the construction of Damyang Lake in the 1970s, as muddy sediments were deposited on the sand layer.

• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.4
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• pp.20-36
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• 2022

This study aims to provide basic data for high-quality street tree management by setting reasonable management items and appropriate unit prices by reviewing the adequacy of current street tree management. Currently, street tree management items, except for street tree pruning, use general landscape tree quantity per unit for the street tree management quantity per unit. KEPCO (Korea Electric Power Corporation) applied pruning items from standard electric production infrastructure and carried out the activities at an average unit price of 51% lower for heavy pruning and 39% lower for light pruning than the standard estimate. This was judged to be a level that could not maintain or increase the quality of street tree management. It was determined that an appropriate standard unit price for street tree management was necessary. To improve the quantity per unit for the proper management of street trees, it was necessary to review costs in the field. However, due to the absence of data on actual construction costs in the domestic landscape field, detailed items of the US RSMeans Building Construction Cost Data (RSMeans) were reviewed, and the actual construction costs were calculated by applying personal domestic expenses. As a result, the standard of the estimated unit showed a good ratio of 107% for heavy pruning of street tree pruning compared to the actual construction cost, but light pruning was underestimated with a 59% ratio. Shrub pruning was 82%, weeding was 92%, tree fertilization was 87%, and windbreak wall installation was 91% under-engineered. In addition, it was also confirmed that the watering by sprinkler trucks and chemical spraying were over-designed compared to the actual construction cost at the rates of 118% and 124%, respectively. Due to the specificity of the street trees, the increase in personal expenses and the input cost of equipment, such as road safety controls, were judged to be the main cause of the underestimation of items. Therefore, it is necessary to add items related to street trees and general landscape trees to the landscape maintenance items of the standard of the estimated unit.

• Journal of the Daesoon Academy of Sciences
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• v.28
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• pp.207-241
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• 2017

In the scripture of Daesoon Jinrihoe, the expression 'Dosu (度數)' is frequently used and Jeungsan, Jeongsan, and Wudang also left behind many teachings related to Dosu. In this paper, the concept of Dosu is analyzed in detail and the achievement of an in-depth understanding of the concept of Dosu is attempted. The term Dosu is often used in traditional literature. In the classics, Dosu was used to mean institutions, standards, rules, law, figures, and the laws of heavenly bodies. In other words, Dosu is used to mean the laws of astronomy and the norms of human society. This meaning is expanded and used as the principle of the universe and nature. This concept of Dosu is related to the mathematical cosmological understanding of numbers as the principle of the universe. This type of mathematical cosmology was systematized by Shao Yong (邵雍). In the Joseon Dynasty, Seo Gyungduk (徐敬德) accepted it positively, and it thereby became an influential trend in Korean thought. In the world view of Daesoon thought, there exists the view that numbers as a principle of the universe, and of course this world view is connected to mathematical cosmology. In Daesoon thought, the concept of Dosu is based on the concept of traditional Dosu and adds an additional meaning which connects it to the Reordering of the Universe (Cheonjigongsa). Also, Dosu is used to mean the process of changing the principles and laws of cosmos through Jeungsan's Reordering of the Universe. It is especially the case that discourse about Dosu is widely used when describing the Reordering of the Universe. Jeungsan corrected, reorganized, and adjusted Dosu, as well as establishing new Dosu. Jeongsan, who succeeded Jeungsan, followed the Reordering of the Universe by Jeungsan, and also realized Dosu. In other words, Jeongsan acted and practiced according to the Dosu that had been enacted by Jeungsan. Also, Dosu means the process of the transformation of principle according to the Reordering of the Universe, and Wudang used the concept of Dosu to describe the historical process of Daesoon Jinrihoe. This means that the foundation of Mugeukdo, the change to Taegukdo, the establishment of Daesoon Jinrihoe, and the contruction of Yeoju headquarters are episodes in a divine history carried out through Dosu. Through this discourse, Daesoon Jinrihoe asserts a legitimacy that distinguishes itself from other sects, and believers can be inspired by the sacred meaning that they are participating in the Dosu of heaven and earth. This empowers their devotion and sincerity.

• Korean Journal of Ecology and Environment
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• v.55 no.1
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• pp.1-9
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• 2022

An estuary is an area where a freshwater river or stream meets the ocean. Even before the importance of the value of estuaries was recognized, the estuary was lost because of large-scale conversion by draining, filling, damming, and dredging. In South Korea, 643 estuaries are located, and the total area is 3,248,300 ha, accounting for 32.5% of the total area of South Korea. Over 35% of Korean estuaries are closed estuaries which are only temporally connected with the sea, either permanently or periodically. Since 2008, in order to preserve the estuary ecosystem and solve major issues in the estuary by accumulating knowledge about the estuarine ecosystem, the Ministry of Environment of Republic of Korea has been conducting the "Estuarine Ecosystem Monitoring and Assessment Project". At 668 sites of 325 estuaries, epilithic diatom, benthic macroinvertebrate, fish, and vegetation are investigated, and the habitat condition of each site is evaluated using the newly developed biotic index. More than 100 researchers annually record 2,097 species of estuaries according to the standardized survey guidelines over the past 14 years and provide strictly managed data necessary for establishing estuaries conservation policies. As a result of bibliometric analysis of 1,195 research articles related to the monitoring and assessment of the estuarine ecosystem, research on pollutants such as heavy metals and sediment control have recently been conducted. "Estuarine Ecosystem Monitoring and Assessment Project" is an ecological monitoring type of long-term mandated monitoring that is usually focused on identifying trends. Although it is difficult to identify the mechanism influencing a change in an ecosystem through long-term mandated monitoring, providing empirical data for supporting evidence-based policy, decision-making, and the management of ecosystems. In order to increase the efficiency of the project, research to investigate the relationship between sediments and pollutants and organisms can be conducted at specific estuaries or sites to compensate for the shortcomings of mandatory monitoring.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.6-7
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• 2021

Vegetation development in rivers is one of the important issues not only in academic fields such as geomorphology, ecology, hydraulics, etc., but also in river management practices. The problem of river vegetation is directly connected to the harmony of conflicting values of flood management and ecosystem conservation. In Korea, since the 2000s, the issue of river vegetation and land formation has been continuously raised under various conditions, such as the regulating rivers downstream of the dams, the small eutrophicated tributary rivers, and the floodplain sites for the four major river projects. In this background, this study proposes a method for classifying the distribution of vegetation in rivers based on remote sensing data, and presents the results of applying this to the Naeseong Stream. The Naeseong Stream is a representative example of the river landscape that has changed due to vegetation development from 2014 to the latest. The remote sensing data used in the study are images of Sentinel 1 and 2 satellites, which is operated by the European Aerospace Administration (ESA), and provided by Google Earth Engine. For the ground truth, manually classified dataset on the surface of the Naeseong Stream in 2016 were used, where the area is divided into eight types including water, sand and herbaceous and woody vegetation. The classification method used a random forest classification technique, one of the machine learning algorithms. 1,000 samples were extracted from 10 pre-selected polygon regions, each half of them were used as training and verification data. The accuracy based on the verification data was found to be 82~85%. The model established through training was also applied to images from 2016 to 2020, and the process of changes in vegetation zones according to the year was presented. The technical limitations and improvement measures of this paper were considered. By providing quantitative information of the vegetation distribution, this technique is expected to be useful in practical management of vegetation such as thinning and rejuvenation of river vegetation as well as technical fields such as flood level calculation and flow-vegetation coupled modeling in rivers.

• Journal of Korea Water Resources Association
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• v.56 no.1
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• pp.53-62
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• 2023

Recently, due to the influence of climate change, the occurrence of damage to heavy rain is increasing around the world, and the frequency of heavy rain with a large amount of rain in a short period of time is also increasing. Heavy rains generate a large amount of outflow in a short time, causing flooding in the downstream part of the mountainous area before joining the small and medium-sized rivers. In order to reduce damage to downstream areas caused by flooding, it is very important to calculate the outflow of mountainous areas due to torrential rains. However, the sewage network flooding analysis, which is currently conducting the most analysis in Korea, uses the time and area method using the existing data rather than calculating the rainfall outflow in the mountainous area, which is difficult to determine that the soil characteristics of the region are accurately applied. Therefore, if the rainfall is analyzed for mountainous areas that can cause flooding in the downstream area in a short period of time due to large outflows, the accuracy of the analysis of flooding characteristics that can occur in the downstream area can be improved and used as data for evacuating residents and calculating the extent of damage. In order to calculate the rainfall outflow in the mountainous area, the rainfall outflow in the mountainous area was calculated using MIKE SHE among the MIKE series, and the flooding analysis in the downstream area was conducted through MIKE 21 FM (Flood model). Through this study, it was possible to confirm the amount of outflow and the time to reach downstream in the event of rainfall in the mountainous area, and the results of this analysis can be used to protect human and material resources through pre-evacuation in the downstream area in the future.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1D
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• pp.25-32
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• 2009

Currently, various types of TDM (Transportation Demand Management) policies are being studied and implemented in an attempt to overcome the limitations of supply oriented policies. In this context, this paper addressed issues of effectiveness and possible domestic implementation of the HOT lane. The possible site of implementation selected for this simulation study is part of the Kyung-bu freeway, where a dedicated bus lane is currently being operated. Minimum length of distance required in between interchanges and access points of the HOT lane for vehicles to safely enter and exit the lane, and traffic management policies for effectively managing the weaving traffic trying to enter and exit the HOT lane were presented. A 5.2km section of freeway from Ki-heuing IC to Suwon IC and a 8.3km section from Hak-uei JC to Pan-gyo JC have been selected as possible sites of implementation for the HOT lane, in which congestion occurs regularly due to the high level of travel demand. VISSIM simulation program has been used to analyze the effects of the HOT lane under the assumption that one-lane HOT lane has been put into operation in these sections and that the lane change rate were in between 5% to 30%. The results of each possible scenario have proven that overall travel speed on the general lanes have increased as well by 1.57~2.62km/h after the implementation of the HOT lane. It is meaningful that this study could serve as a basic reference data for possible follow-up studies on the HOT lane as one effective method of TDM policies. Considering that the bus travel rate would continue increase and assuming the improvement in travel speed on general lanes, similar case study can be implemented where gaps between buses on bus lane are available, as a possible alternative of efficient bus lane management policies.