• Journal of the Korean Institute of Landscape Architecture
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• v.31 no.5
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• pp.11-19
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• 2003

The main purpose of this study was to examine the application of the root system as a shore protection material through the measurement of the 개ot growth curve of Salix gracilisyla Miq. depending on the cutting size. As materials and methodology, nine group of cuttings were classified by the length(l0cm, 20cm, 40cm) and the diameter(0.72cmm$\pm$0,02, 0.58cm$\pm$0.02, 0.35cm$\pm$0.02), Each group was stuck to a flooding bed of sandy loam(Sand 60,36%, Silt 28%, Clay 11.64%) on 27th March 2001, After 65 growing days, the weight and length of the newly developed roots, shoots, and leaves were measured and analysed, This was repeated at 99, 129, 159, and 190 growing days. The major findings were as follows. The primary determinant of the root growth rate was on the weight of cutting, The secondary determinant was on the number of growing days. In addition, the dominant dimension of the cutting was the diameter rather than the length, The thicker cutting caused more rapid and stable growth however the longer cutting made the growth of the root slower and more unstable.

• Journal of Urban Science
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• v.12 no.2
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• pp.1-6
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• 2023

Due to abnormal climate patteZns, recent extreme weather events such as floods, occurring more frequently than once in a century, have become a common occurrence. This has resulted in frequent urban flooding due to the inadequate capacity of sewage pipelines, originally designed to handle floods occurring once every 20 to 30 years. To tackle this situation, measures such as partial flow retention through reservoirs, flood control facilities, and underground tanks have been implemented. In this study, the Storm Water Management Model, a sewage pipeline model developed by the U.S. Environmental Protection Agency (U.S. EPA), was used to analyze the flow capacity of sewage pipelines on the campus of Daegu University and to conduct research on pollutant reduction through superior control facilities. When the allowable flow velocity, ranging from 0.8 m/s to 3.0 m/s, could not be met, the slope of the sewage pipeline was adjusted through step junctions. The simulation demonstrated a 20% reduction in peak flow, decreasing from 0.69 cm/s to 0.55 cm/s, through the implementation of flow regulation facilities. It is anticipated that the findings of this study can serve as valuable data for adjusting flow velocity and reducing peak flow within the pipelines.

• Journal of Korean Society of Disaster and Security
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• v.17 no.2
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• pp.1-11
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• 2024

Most reservoirs in South Korea are earthen dams, mainly because they are cost-effective and easy to construct. However, earthen dams are highly vulnerable to seepage and overtopping, making them prone to sudden failure during excessive flooding. Such sudden failures can lead to a rapid increase in flood discharge, causing significant damage to downstream rivers and inhabited areas. This study investigates the effect of riprap placement on the slopes of earthen dams in delaying dam failure. Delaying the failure time is crucial as it allows more time for evacuation, significantly reducing potential casualties, which is essential from a disaster response perspective. Hydraulic experiments were conducted in a straight channel, using two different sizes of riprap for protection. Unlike previous studies, these experiments were performed under unsteady flow conditions to reflect the impact of rising water levels inside the dam. The target dam for the study was a cofferdam installed in a diversion tunnel. Experimental results indicated that the presence of riprap protection effectively prevented slope failure under the tested conditions. Without riprap protection, increasing the size of the riprap delayed the failure time. This delay can reduce peak discharge, mitigating damage downstream of the dam. Furthermore, these findings can serve as critical reference material for establishing emergency action plans (EAP) for reservoir failure.

• Journal of the Korean Society of Safety
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• v.35 no.1
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• pp.107-115
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• 2020

This paper introduces the first vital area identification (VAI) process for the physical protection of nuclear power plants (NPPs) during low power and shutdown (LPSD) operation. This LPSD VAI is based on the 3rd generation VAI method which very efficiently utilizes probabilistic safety assessment (PSA) event trees (ETs). This LPSD VAI process was implemented to the virtual NPP during LPSD operation in this study. Korea Atomic Energy Research Institute (KAERI) had developed the 2nd generation full power VAI method that utilizes whole internal and external (fire and flooding) PSA results of NPPs during full power operation. In order to minimize the huge burden of the 2nd generation full power VAI method, the 3rd generation full power VAI method was developed, which utilizes ETs and minimal PSA fault trees instead of using the whole PSA fault tree. In the 3rd generation full power VAI method, (1) PSA ETs are analyzed, (2) minimal mitigation systems for avoiding core damage are selected from ETs by calculating system-level target sets and prevention sets, (3) relatively small sabotage fault tree that has the systems in the shortest system-level prevention set is composed, (4) room-level target sets and prevention sets are calculated from this small sabotage fault tree, and (5) the rooms in the shortest prevention set are defined as vital areas that should be protected. Currently, the 3rd generation full power VAI method is being employed for the VAI of Korean NPPs. This study is the first development and application of the 3rd generation VAI method to the LPSD VAI of NPP. For the LPSD VAI, (1) many LPSD ETs are classified into a few representative LPSD ETs based on the functional similarity of accident scenarios, (2) a few representative LPSD ETs are simplified with some VAI rules, and then (3) the 3rd generation VAI is performed as mentioned in the previous paragraph. It is well known that the shortest room-level prevention sets that are calculated by the 2nd and 3rd generation VAI methods are identical.

• Journal of Digital Convergence
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• v.10 no.8
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• pp.29-37
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• 2012

Defamation is one of the most frequently occurring daily legal violation because it can easily be done by words. In the internet generation with flooding internet forum websites and social network services, internet defamation is becoming one of the most serious problems in many leading IT countries including Korea and the United States. Being such a critical issue that can lead to a suicide, Korean policy makers has undertaken efforts to prevent the internet defamation by defining the liabilities of internet users and internet service providers. Many of the policies and laws including "the Telecommunication Information Usage Promotion and Security Protection Act of 2007" are modeled after that of the United States. Thus, the study aims to explore American defamation law and internet defamation law analyzing "the Communications Decency Act of 1996" and a recently decided precedent, "Brodie" case, in Maryland state court.

• Journal of Korea Water Resources Association
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• v.40 no.5
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• pp.397-407
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• 2007

The deposition of sewer solids during dry weather in combined sewer systems results in a loss of flow capacity that may restrict flow and cause a local flooding and enhanced solids deposition. In order to solve these problems and to manage sewer systems efficiently, development of estimation equations for solid sediments In sewer systems is needed. However, estimation of solid sediments has performed using specific methods such as computer model before the development of estimation equations. In this study, solid sediments in sewer systems were estimated using MOUSE model for Gunja drainage basin in Korea and the estimated results were verified using estimation equations developed by the U.S. Environmental Protection Agency. As results, the estimated values using MOUSE model are smaller than that of equations developed in 1977 but greater than that of equations developed in 1984. Although the comparison between simulated and measured solid deposition is difficult due to the absent of measurement data, the estimated values using MOUSE model is reliable and can be used to develop estimation equations for solid sediment in Gunja drainage basin.

• Journal of the Korean Society of Safety
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• v.30 no.6
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• pp.48-55
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• 2015

A variety of safety issues were investigated for chemical reactors using a toluene solvent in case of a fire at small to middle scale chemical plants. The issues covered the operation of pressure-relieving valves and the subsequent discharges of the toluene to the atmosphere either directly or through an absorber, which represent the current practice at most small chemical plants. It was shown that the safety valve on the reactor may not operate within about twenty minutes after an external fire breaks out, but, once relieved, the toluene vapor released directly to the atmosphere may form a large explosion range on the ground. It was also shown that if the discharge is routed to an existing absorber used for the scrubbing of volatile organic compounds or dusts, the column may not operate normally due to excessive pressure drops or flooding, resulting in the hazardous release of toluene vapors. This study proposed two ways of alleviating these risks. The first is to ruduce the discharge itself from the safety valve by using adequate insulation and protection covers on the reactor and then introduce it into the circulation water at the bottom of the absorber through a dip linet pipe equipped with a ring-shaped sparger. This will enhance the condensation of toluene vapors with the reduced effluent vapors treated in the packing layers above. The second is to install a separate quench drum to condense the routed toluene vapors more effectively than the existing absorber.

• Journal of Wetlands Research
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• v.14 no.4
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• pp.547-559
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• 2012

Abandoned channel is vestiges of running in the past. Abandoned channels have been formed mostly by artificial river maintenance through channel straightening in Korea. Managed properly, these now abandoned channels can provide habitat for wildlife, maintain biodiversity of aquatic life, security against flooding and recreation area for human. However, because the areas are officially classified as abandoned, the channels is collapsing and decaying from years of neglect. This study suggested functional assessment for wetland-type abandoned channel in order to provide appropriate management and investment. For this reason, The study will examine and evaluate these channels with regard to the following four major criteria (Natureless, Habitat, Water-friendliness and Water quality) and 21 indices. Consequently, abandoned channel in two Nakdong river sites, site 1 was needed for protection or improvement in the medium to longer term, while site 2 was in good condition. This evaluation method will be helpful to manage wetland-type abandoned channel in Korea and will be able to use National River Health Program.

• Fire Science and Engineering
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• v.30 no.5
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• pp.46-53
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• 2016

Wooden cultural heritage is vulnerable to fire, flooding and other hazards. Therefore, an effective disaster prevention and mitigation strategy for them should include preventive measures in a full range of management. These were used to construct a disaster safety system for 508 wooden cultural heritage items by the Cultural Heritage Administration. According to the type of ownership and administration, national and public heritage is controlled by personal management or commissional management. Among them, it is arranged with the safety security institute for important cultural properties. In addition, they have problems of field management with no computerization about the management information for a disaster facility system. Therefore, this study aimed to develop a DB platform that can share information with many users who need to manage cultural heritage. Through a field survey, it is feasible to develop a disaster facility system to provide the information, such as the main data, quantity and location.

• The Journal of the Convergence on Culture Technology
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• v.6 no.4
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• pp.709-714
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• 2020

Forest resources are the most important element that can affect the nature environment directly in modern society. Due to the fast industrialization of our country and marginal states like China, many people suffer torments from severe environmental pollution like yellow and fine dusts everyday recently. So the interests concerned about the significance of nature and environment become major issue nowadays. Precious forest resources, however, are not properly managed and destroyed vainly due to frequent mountain fires, damages by floods, and unplanned land development in real world. Therefore, efficient forest management is required to solve these problems effectively. In this research, we design and implement the forest information database that can predict the growth of forest resources and enables us to manage forest resources efficiently, make decision for logging, build the waterway to prevent flooding, and construct a future tree-planting project easily using forest aerial photograph taken by a drone in order to deploy and manage the forest resources scientifically and systematically.