• Journal of Korea Water Resources Association
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• v.55 no.3
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• pp.191-203
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• 2022

This study is a follow-up study of vulnerable areas according to the vulnerability assessment of groundwater resource management in Korea. In this study, an optimal operation plan for groundwater resource management was proposed for areas vulnerable to groundwater resource management in Korea derived from previous studies. Prior to presenting the optimal operation plan for groundwater resource management, this study grasped the current status of changes in groundwater level and seawater penetration area for vulnerable areas using MODFLOW, a groundwater flow analysis program. As a result of the analysis using basic data for 10 years from 2009 to 2018, the groundwater level fell and the sea infiltration area increased. The final purpose of this study, the optimal operation plan for groundwater resource management, was selected as a total of four alternatives that can be expected to have positive effects to increase groundwater level and reduce seawater penetration. As a result of analyzing the amount of change in groundwater level and seawater penetration by applying the selected optimal operation plan, positive effects were found in all methods. It is expected that the optimal operation plan for groundwater resource management proposed in this study will be applied not only to vulnerable areas of groundwater resources in Korea but also to areas requiring development to establish efficient groundwater resource management measures.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.7
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• pp.1238-1243
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• 2022

The International Maritime Organization is at the forefront of strengthening gas emission regulations for ships globally. The Korean government needs to apply measures to reduce emissions, such as setting a basic roadmap for greenhouse gas reduction. In addition, there is an urgent need to introduce a new efficient propulsion system that can reduce gas emissions. This includes applications to fishing vessels, which account for 90.6% of the greenhouse gas emissions from ships sailing along domestic coasts. In this study, an electric-combined propulsion system applicable to domestic coastal fishing vessels was developed. The target ship to which the electric-combined propulsion system could be applied was selected. A simulation system was constructed using MATLAB/Simulink to compare the expected fuel consumption when applying the developed complex electric propulsion system to the propulsion system mounted on the selected target fishing vessel. Through simulations, the differences in fuel consumption between the mechanical propulsion system and the electric hybrid propulsion system (both when charging and not charging the battery on land) were confirmed. The results show that fuel consumption can be decreased by approximately 13% and 16% when applying the electric-combined propulsion system.

• Journal of Navigation and Port Research
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• v.47 no.1
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• pp.37-48
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• 2023

Recently, the increase of international trade volume is leading to risk exposure and safety accidents in the port terminal industry. In addition, as Serious Disaster Punishment Act came into effect on January, 2021, various guidelines and laws to protect safety and life in port terminals are being enacted. However, despite these efforts, medium-to-large safety accidents in the port terminal industry have occurred. According to the Korea Occupational Safety and Health Agency, from 2016 to 2019, the number of casualties in the port handling industry increased by 4.2%. To build some effective follow-up management of port accidents and preparation of related safety laws/systems, a risk analysis in consideration of causes and damage of accidents should be conducted. Therefore, in this study, major risk factors and preventive measures were derived by conducting risk assessment based on 1,039 cases of port terminal accidents collected by the Korea Occupational Safety and Health Agency for five years. Priorities for preventive measures were then determined through IPA analysis, Borich needs analysis, and The Locus For Focus analysis.

• The Journal of the Acoustical Society of Korea
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• v.42 no.2
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• pp.133-142
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• 2023

The office environment is changing according to work types, Information Technology (IT) advancements, and the Coronavirus disease (COVID)-19 situation. In order for office space users to perform their tasks comfortably and efficiently, it is necessary to secure individual privacy as well as easy communication among members. In Korea, the demand for improving the acoustic performance of office spaces is also increasing, but the related performance criteria and guidelines have not been established. In this study, standardization of office space acoustic performance measurement and evaluation methods and European countries' acoustic performance criteria were compared and reviewed. It is proposed to comprehensively review international standardization trends and acoustic performance standards in each country and to establish and utilize criteria for evaluating the acoustic performance and satisfaction of office spaces in Korea through our survey. Considering the international standardization direction and compatibility with communication and Public Address (PA) systems, it is appropriate to establish criteria using the speech transmission index or Speech Transmission Index (STI) application index. This criterion will be highly utilizable and compatible. In addition, since the office furniture industry is interested in improving the acoustic performance of office space, it is necessary to establish a labelling system for speech level reduction of office furniture.

• Korean Journal of Environmental Biology
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• v.40 no.1
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• pp.99-111
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• 2022

Vegetation is the basis for biodiversity conservation and sustainable development. In the Environmental Impact Assessment (EIA), which is the most direct and efficient policy measure to prevent degradation of nature, vegetation-related assessment has limitations as it is not based on quantitative and scientific methods. In addition, it focuses on the presence of protected species; hence, it does not take into account the role of vegetation as a habitat on a wide-area scale. As a way to overcome these limitations, this study aims to contribute to the quantification and advancement of future EIA on vegetation. Through the review of previous studies, core areas, connectivity, and vegetation condition were derived as the items to be dealt within the macroscopic aspect of vegetation impact assessment. Each item was spatially constructed using land cover maps and satellite imageries, and time series change analysis was performed. As a result, it was found that vegetation has been continuously deteriorating due to development in all aspects, and in particular, development adversely affects not only the inside of the project site but also the surrounding area. Although this study suggested the direction for improvement of the EIA in the vegetation sector based on data analysis, a more specific methodology needs to be established in order to apply it to the actual EIA process. By actively utilizing various environmental spatial data, the impact of the development on the natural ecosystem can be minimized.

• Korean Chemical Engineering Research
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• v.61 no.3
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• pp.368-377
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• 2023

Natural Gas Combined Cycle(NGCC) recently receives lots of attention as an attractive form of power plants by virtue of its low carbon emission compared with coal-fired power plant. Nevertheless, it also needs carbon capture process since it is difficult to completely suppress carbon emission even for the NGCC. A simulation study has been performed to optimize operating condition of a carbon capture process using MEA considering low partial pressure of carbon dioxide in NGCC emission gas. For accurate optimization, overall process model including both NGCC and the carbon capture process has been built with a simulation software. Then, optimization in which various performance indices such as carbon dioxide absorption rate, solvent regeneration rate and power loss in the NGCC are simultaneously reflected has been done. Especially, it is noticeable that this study focuses on not only the amount of energy consumption but also the absorption and regeneration performance of carbon capture process. The best result considering all the performance indices has been achieved when the reboiler temperature is 120 ℃ and the reason has been analyzed.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.4
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• pp.285-303
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• 2023

Interest in building underground spaces is increasing for the creation of downtown infrastructure and efficient space utilization. A representative method of utilizing underground space is a tunnel, and in addition to road tunnels, the construction of utility tunnels such as power conduits and utility conduits is gradually increasing. The current basic tunnel construction method can be divided into NATM (New Austrian Tunnelling Method) and TBM (Tunnel Boring Machine). The NATM is a reliable method, but it is accompanied by vibration and noise due to blasting. In the case of the TBM excavation method, there are disadvantages in terms of construction period and construction cost, but it is possible to improve economic feasibility by introducing appropriate complementary methods. In this study, a blasting method was develop using the NATM after TBM pre-excavation using the protective shield method. This is a method that compensates for the disadvantages of each tunnel construction method, and is expected to reduce construction costs, blasting vibration, and noise. In order to review the performance of the developed method, an experiment was conducted to evaluate the performance of explosion-proof tube to which a protective shield scale model was applied, and the impact of blasting vibration of the protective shield method was analyzed.

• Journal of the Korean GEO-environmental Society
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• v.24 no.8
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• pp.5-11
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• 2023

Due to frequent occurrences of concentrated heavy rainfall caused by abnormal climate conditions in recent years, collapses of steep slopes have been occurring frequently due to surface erosion and increased pore water pressure. Various methods are being applied to prevent slope collapses, such as increasing the resistance to movement and reducing pore water pressure. Research on these methods has been consistently conducted as they provide an efficient response to slope collapses by satisfying both the conditions of resistance to movement and pore water pressure simultaneously. Therefore, in this study, we propose an upward slope reinforcement method by burying drainage materials with an upward slope inclination, instead of the conventional horizontal application. This approach aims to satisfy both slope reinforcement and drainage functions effectively, offering a comprehensive solution for slope stabilization. Furthermore, to determine the optimal burial angle that exhibits the most effective reinforcement and drainage effects of the proposed method, we investigated the reinforcement and drainage effects under conditions where the horizontal drainage materials were set at angles ranging from 0° to 60° in increments of 10° on a representative cross-section. Additionally, indoor model experiments were conducted under the conditions of 40°, which showed the most outstanding drainage effect, and 20°, which exhibited the highest safety factor, to validate the numerical analysis results. The results showed that the burial angle of 40° exhibits a relatively higher drainage effect as with the numerical analysis results, while the angle of 20° results in inadequate drainage and observed slope collapse.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5B
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• pp.479-486
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• 2010

Reliable hydrologic data acquisition is the basic and essential requirement for efficient water management. Especially the acquisition of various stream data in a certain location is very important to construct on alarm system to response an urban flood which occurs frequently due to the effect of climate change. Although the frequency of stream inundation flood occurrence becomes low owing to the consistent stream improvement, the urban flood due to the drainage system problems such as deterioration and bad management occurs continuously. The consistent management and current status understanding of the urban drainage system is essential to reduce the urban flood. The purpose of this study is to develop the urban runoff network flow velocity monitoring system which has the capability of collecting stream data whenever, wherever and to whomever without expert knowledge using Code Division Multiple Access technique and Bluetooth near-distance wireless communication technique. The urban runoff network flow velocity monitoring system consists of three stages. In the first stage, the stream information obtained by using ubiquitous floater is transferred to the server computer. In the second stage, the current state of the urban drainage system is assessed through the server computer. In the last stage, the information is provided to the user through a GUI. As a result of applying, the developed urban runoff network flow velocity monitoring system to Woncheon-Stream in Suwon, the information necessary for urban drainage management can be managed in real time.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.389-390
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• 2022

Recently, Recently, the increase in international trade volume and the explosive increase in cargo volume due to the non-face-to-face society are leading to an increase in risk exposure and safety accidents in the port industry. In addition, as the Serious Disaster Punishment Act came into effect on January 27, 2021, various guidelines and laws to protect safety and life in port terminals are being enacted. However, despite these efforts, medium-to-large safety accidents in the port terminal industry continue to occur. According to the Korea Occupational Safety and Health Agency, from 2016 to 2019, the number of casualties in the port handling industry increased by 4.2%. For effective follow-up management of port accidents or the preparation of related safety laws/systems, a risk analysis in consideration of the cause and damage of the accident must be conducted first, so that realistic accident reduction and prevention measures can be established. Therefore, in this study, major risk factors and preventive measures were derived by conducting risk assessment based on 1,039 cases of port terminal accidents collected by the Korea Occupational Safety and Health Agency for 5 years from 2016 to 2022. After that, the priorities for preventive measures were determined through IPA analysis, Borich needs analysis, and The Locus For Focus analysis.